1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25 * Copyright 2019 Joyent, Inc.
26 * Copyright (c) 2014, 2016 by Delphix. All rights reserved.
27 */
28
29 /* This file contains all TCP input processing functions. */
30
31 #include <sys/types.h>
32 #include <sys/stream.h>
33 #include <sys/strsun.h>
34 #include <sys/strsubr.h>
35 #include <sys/stropts.h>
36 #include <sys/strlog.h>
37 #define _SUN_TPI_VERSION 2
38 #include <sys/tihdr.h>
39 #include <sys/suntpi.h>
40 #include <sys/xti_inet.h>
41 #include <sys/squeue_impl.h>
42 #include <sys/squeue.h>
43 #include <sys/tsol/tnet.h>
44
45 #include <inet/common.h>
46 #include <inet/ip.h>
47 #include <inet/tcp.h>
48 #include <inet/tcp_impl.h>
49 #include <inet/tcp_cluster.h>
50 #include <inet/proto_set.h>
51 #include <inet/ipsec_impl.h>
52
53 /*
54 * RFC7323-recommended phrasing of TSTAMP option, for easier parsing
55 */
56
57 #ifdef _BIG_ENDIAN
58 #define TCPOPT_NOP_NOP_TSTAMP ((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | \
59 (TCPOPT_TSTAMP << 8) | 10)
60 #else
61 #define TCPOPT_NOP_NOP_TSTAMP ((10 << 24) | (TCPOPT_TSTAMP << 16) | \
62 (TCPOPT_NOP << 8) | TCPOPT_NOP)
63 #endif
64
65 /*
66 * PAWS needs a timer for 24 days. This is the number of ticks in 24 days
67 */
68 #define PAWS_TIMEOUT ((clock_t)(24*24*60*60*hz))
69
70 /*
71 * Since tcp_listener is not cleared atomically with tcp_detached
72 * being cleared we need this extra bit to tell a detached connection
73 * apart from one that is in the process of being accepted.
74 */
75 #define TCP_IS_DETACHED_NONEAGER(tcp) \
76 (TCP_IS_DETACHED(tcp) && \
77 (!(tcp)->tcp_hard_binding))
78
79 /*
80 * Steps to do when a tcp_t moves to TIME-WAIT state.
81 *
82 * This connection is done, we don't need to account for it. Decrement
83 * the listener connection counter if needed.
84 *
85 * Decrement the connection counter of the stack. Note that this counter
86 * is per CPU. So the total number of connections in a stack is the sum of all
87 * of them. Since there is no lock for handling all of them exclusively, the
88 * resulting sum is only an approximation.
89 *
90 * Unconditionally clear the exclusive binding bit so this TIME-WAIT
91 * connection won't interfere with new ones.
92 *
93 * Start the TIME-WAIT timer. If upper layer has not closed the connection,
94 * the timer is handled within the context of this tcp_t. When the timer
95 * fires, tcp_clean_death() is called. If upper layer closes the connection
96 * during this period, tcp_time_wait_append() will be called to add this
97 * tcp_t to the global TIME-WAIT list. Note that this means that the
98 * actual wait time in TIME-WAIT state will be longer than the
99 * tcps_time_wait_interval since the period before upper layer closes the
100 * connection is not accounted for when tcp_time_wait_append() is called.
101 *
102 * If upper layer has closed the connection, call tcp_time_wait_append()
103 * directly.
104 *
105 */
106 #define SET_TIME_WAIT(tcps, tcp, connp) \
107 { \
108 (tcp)->tcp_state = TCPS_TIME_WAIT; \
109 if ((tcp)->tcp_listen_cnt != NULL) \
110 TCP_DECR_LISTEN_CNT(tcp); \
111 atomic_dec_64( \
112 (uint64_t *)&(tcps)->tcps_sc[CPU->cpu_seqid]->tcp_sc_conn_cnt); \
113 (connp)->conn_exclbind = 0; \
114 if (!TCP_IS_DETACHED(tcp)) { \
115 TCP_TIMER_RESTART(tcp, (tcps)->tcps_time_wait_interval); \
116 } else { \
117 tcp_time_wait_append(tcp); \
118 TCP_DBGSTAT(tcps, tcp_rput_time_wait); \
119 } \
120 }
121
122 /*
123 * If tcp_drop_ack_unsent_cnt is greater than 0, when TCP receives more
124 * than tcp_drop_ack_unsent_cnt number of ACKs which acknowledge unsent
125 * data, TCP will not respond with an ACK. RFC 793 requires that
126 * TCP responds with an ACK for such a bogus ACK. By not following
127 * the RFC, we prevent TCP from getting into an ACK storm if somehow
128 * an attacker successfully spoofs an acceptable segment to our
129 * peer; or when our peer is "confused."
130 */
131 static uint32_t tcp_drop_ack_unsent_cnt = 10;
132
133 /*
134 * To protect TCP against attacker using a small window and requesting
135 * large amount of data (DoS attack by conuming memory), TCP checks the
136 * window advertised in the last ACK of the 3-way handshake. TCP uses
137 * the tcp_mss (the size of one packet) value for comparion. The window
138 * should be larger than tcp_mss. But while a sane TCP should advertise
139 * a receive window larger than or equal to 4*MSS to avoid stop and go
140 * tarrfic, not all TCP stacks do that. This is especially true when
141 * tcp_mss is a big value.
142 *
143 * To work around this issue, an additional fixed value for comparison
144 * is also used. If the advertised window is smaller than both tcp_mss
145 * and tcp_init_wnd_chk, the ACK is considered as invalid. So for large
146 * tcp_mss value (say, 8K), a window larger than tcp_init_wnd_chk but
147 * smaller than 8K is considered to be OK.
148 */
149 static uint32_t tcp_init_wnd_chk = 4096;
150
151 /* Process ICMP source quench message or not. */
152 static boolean_t tcp_icmp_source_quench = B_FALSE;
153
154 static boolean_t tcp_outbound_squeue_switch = B_FALSE;
155
156 static mblk_t *tcp_conn_create_v4(conn_t *, conn_t *, mblk_t *,
157 ip_recv_attr_t *);
158 static mblk_t *tcp_conn_create_v6(conn_t *, conn_t *, mblk_t *,
159 ip_recv_attr_t *);
160 static boolean_t tcp_drop_q0(tcp_t *);
161 static void tcp_icmp_error_ipv6(tcp_t *, mblk_t *, ip_recv_attr_t *);
162 static mblk_t *tcp_input_add_ancillary(tcp_t *, mblk_t *, ip_pkt_t *,
163 ip_recv_attr_t *);
164 static void tcp_input_listener(void *, mblk_t *, void *, ip_recv_attr_t *);
165 static void tcp_process_options(tcp_t *, tcpha_t *);
166 static mblk_t *tcp_reass(tcp_t *, mblk_t *, uint32_t);
167 static void tcp_reass_elim_overlap(tcp_t *, mblk_t *);
168 static void tcp_rsrv_input(void *, mblk_t *, void *, ip_recv_attr_t *);
169 static void tcp_set_rto(tcp_t *, hrtime_t);
170 static void tcp_setcred_data(mblk_t *, ip_recv_attr_t *);
171
172 /*
173 * CC wrapper hook functions
174 */
175 static void
176 cc_ack_received(tcp_t *tcp, uint32_t seg_ack, int32_t bytes_acked,
177 uint16_t type)
178 {
179 uint32_t old_cwnd = tcp->tcp_cwnd;
180
181 tcp->tcp_ccv.bytes_this_ack = bytes_acked;
182 if (tcp->tcp_cwnd <= tcp->tcp_swnd)
183 tcp->tcp_ccv.flags |= CCF_CWND_LIMITED;
184 else
185 tcp->tcp_ccv.flags &= ~CCF_CWND_LIMITED;
186
187 if (type == CC_ACK) {
188 if (tcp->tcp_cwnd > tcp->tcp_cwnd_ssthresh) {
189 if (tcp->tcp_ccv.flags & CCF_RTO)
190 tcp->tcp_ccv.flags &= ~CCF_RTO;
191
192 tcp->tcp_ccv.t_bytes_acked +=
193 min(tcp->tcp_ccv.bytes_this_ack,
194 tcp->tcp_tcps->tcps_abc_l_var * tcp->tcp_mss);
195 if (tcp->tcp_ccv.t_bytes_acked >= tcp->tcp_cwnd) {
196 tcp->tcp_ccv.t_bytes_acked -= tcp->tcp_cwnd;
197 tcp->tcp_ccv.flags |= CCF_ABC_SENTAWND;
198 }
199 } else {
200 tcp->tcp_ccv.flags &= ~CCF_ABC_SENTAWND;
201 tcp->tcp_ccv.t_bytes_acked = 0;
202 }
203 }
204
205 if (CC_ALGO(tcp)->ack_received != NULL) {
206 /*
207 * The FreeBSD code where this originated had a comment "Find
208 * a way to live without this" in several places where curack
209 * got set. If they eventually dump curack from the cc
210 * variables, we'll need to adapt our code.
211 */
212 tcp->tcp_ccv.curack = seg_ack;
213 CC_ALGO(tcp)->ack_received(&tcp->tcp_ccv, type);
214 }
215
216 DTRACE_PROBE3(cwnd__cc__ack__received, tcp_t *, tcp, uint32_t, old_cwnd,
217 uint32_t, tcp->tcp_cwnd);
218 }
219
220 void
221 cc_cong_signal(tcp_t *tcp, uint32_t seg_ack, uint32_t type)
222 {
223 uint32_t old_cwnd = tcp->tcp_cwnd;
224 uint32_t old_cwnd_ssthresh = tcp->tcp_cwnd_ssthresh;
225 switch (type) {
226 case CC_NDUPACK:
227 if (!IN_FASTRECOVERY(tcp->tcp_ccv.flags)) {
228 tcp->tcp_rexmit_max = tcp->tcp_snxt;
229 if (tcp->tcp_ecn_ok) {
230 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
231 tcp->tcp_cwr = B_TRUE;
232 tcp->tcp_ecn_cwr_sent = B_FALSE;
233 }
234 }
235 break;
236 case CC_ECN:
237 if (!IN_CONGRECOVERY(tcp->tcp_ccv.flags)) {
238 tcp->tcp_rexmit_max = tcp->tcp_snxt;
239 if (tcp->tcp_ecn_ok) {
240 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
241 tcp->tcp_cwr = B_TRUE;
242 tcp->tcp_ecn_cwr_sent = B_FALSE;
243 }
244 }
245 break;
246 case CC_RTO:
247 tcp->tcp_ccv.flags |= CCF_RTO;
248 tcp->tcp_dupack_cnt = 0;
249 tcp->tcp_ccv.t_bytes_acked = 0;
250 /*
251 * Give up on fast recovery and congestion recovery if we were
252 * attempting either.
253 */
254 EXIT_RECOVERY(tcp->tcp_ccv.flags);
255 if (CC_ALGO(tcp)->cong_signal == NULL) {
256 /*
257 * RFC5681 Section 3.1
258 * ssthresh = max (FlightSize / 2, 2*SMSS) eq (4)
259 */
260 tcp->tcp_cwnd_ssthresh = max(
261 (tcp->tcp_snxt - tcp->tcp_suna) / 2 / tcp->tcp_mss,
262 2) * tcp->tcp_mss;
263 tcp->tcp_cwnd = tcp->tcp_mss;
264 }
265
266 if (tcp->tcp_ecn_ok) {
267 tcp->tcp_cwr = B_TRUE;
268 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
269 tcp->tcp_ecn_cwr_sent = B_FALSE;
270 }
271 break;
272 }
273
274 if (CC_ALGO(tcp)->cong_signal != NULL) {
275 tcp->tcp_ccv.curack = seg_ack;
276 CC_ALGO(tcp)->cong_signal(&tcp->tcp_ccv, type);
277 }
278
279 DTRACE_PROBE6(cwnd__cc__cong__signal, tcp_t *, tcp, uint32_t, old_cwnd,
280 uint32_t, tcp->tcp_cwnd, uint32_t, old_cwnd_ssthresh,
281 uint32_t, tcp->tcp_cwnd_ssthresh, uint32_t, type);
282 }
283
284 static void
285 cc_post_recovery(tcp_t *tcp, uint32_t seg_ack)
286 {
287 uint32_t old_cwnd = tcp->tcp_cwnd;
288
289 if (CC_ALGO(tcp)->post_recovery != NULL) {
290 tcp->tcp_ccv.curack = seg_ack;
291 CC_ALGO(tcp)->post_recovery(&tcp->tcp_ccv);
292 }
293 tcp->tcp_ccv.t_bytes_acked = 0;
294
295 DTRACE_PROBE3(cwnd__cc__post__recovery, tcp_t *, tcp,
296 uint32_t, old_cwnd, uint32_t, tcp->tcp_cwnd);
297 }
298
299 /*
300 * Set the MSS associated with a particular tcp based on its current value,
301 * and a new one passed in. Observe minimums and maximums, and reset other
302 * state variables that we want to view as multiples of MSS.
303 *
304 * The value of MSS could be either increased or descreased.
305 */
306 void
307 tcp_mss_set(tcp_t *tcp, uint32_t mss)
308 {
309 uint32_t mss_max;
310 tcp_stack_t *tcps = tcp->tcp_tcps;
311 conn_t *connp = tcp->tcp_connp;
312
313 if (connp->conn_ipversion == IPV4_VERSION)
314 mss_max = tcps->tcps_mss_max_ipv4;
315 else
316 mss_max = tcps->tcps_mss_max_ipv6;
317
318 if (mss < tcps->tcps_mss_min)
319 mss = tcps->tcps_mss_min;
320 if (mss > mss_max)
321 mss = mss_max;
322 /*
323 * Unless naglim has been set by our client to
324 * a non-mss value, force naglim to track mss.
325 * This can help to aggregate small writes.
326 */
327 if (mss < tcp->tcp_naglim || tcp->tcp_mss == tcp->tcp_naglim)
328 tcp->tcp_naglim = mss;
329 /*
330 * TCP should be able to buffer at least 4 MSS data for obvious
331 * performance reason.
332 */
333 if ((mss << 2) > connp->conn_sndbuf)
334 connp->conn_sndbuf = mss << 2;
335
336 /*
337 * Set the send lowater to at least twice of MSS.
338 */
339 if ((mss << 1) > connp->conn_sndlowat)
340 connp->conn_sndlowat = mss << 1;
341
342 /*
343 * Update tcp_cwnd according to the new value of MSS. Keep the
344 * previous ratio to preserve the transmit rate.
345 */
346 tcp->tcp_cwnd = (tcp->tcp_cwnd / tcp->tcp_mss) * mss;
347 tcp->tcp_cwnd_cnt = 0;
348
349 tcp->tcp_mss = mss;
350 (void) tcp_maxpsz_set(tcp, B_TRUE);
351 }
352
353 /*
354 * Extract option values from a tcp header. We put any found values into the
355 * tcpopt struct and return a bitmask saying which options were found.
356 */
357 int
358 tcp_parse_options(tcpha_t *tcpha, tcp_opt_t *tcpopt)
359 {
360 uchar_t *endp;
361 int len;
362 uint32_t mss;
363 uchar_t *up = (uchar_t *)tcpha;
364 int found = 0;
365 int32_t sack_len;
366 tcp_seq sack_begin, sack_end;
367 tcp_t *tcp;
368
369 endp = up + TCP_HDR_LENGTH(tcpha);
370 up += TCP_MIN_HEADER_LENGTH;
371 /*
372 * If timestamp option is aligned as recommended in RFC 7323 Appendix
373 * A, and is the only option, return quickly.
374 */
375 if (TCP_HDR_LENGTH(tcpha) == (uint32_t)TCP_MIN_HEADER_LENGTH +
376 TCPOPT_REAL_TS_LEN &&
377 OK_32PTR(up) &&
378 *(uint32_t *)up == TCPOPT_NOP_NOP_TSTAMP) {
379 tcpopt->tcp_opt_ts_val = ABE32_TO_U32((up+4));
380 tcpopt->tcp_opt_ts_ecr = ABE32_TO_U32((up+8));
381
382 return (TCP_OPT_TSTAMP_PRESENT);
383 }
384 while (up < endp) {
385 len = endp - up;
386 switch (*up) {
387 case TCPOPT_EOL:
388 break;
389
390 case TCPOPT_NOP:
391 up++;
392 continue;
393
394 case TCPOPT_MAXSEG:
395 if (len < TCPOPT_MAXSEG_LEN ||
396 up[1] != TCPOPT_MAXSEG_LEN)
397 break;
398
399 mss = BE16_TO_U16(up+2);
400 /* Caller must handle tcp_mss_min and tcp_mss_max_* */
401 tcpopt->tcp_opt_mss = mss;
402 found |= TCP_OPT_MSS_PRESENT;
403
404 up += TCPOPT_MAXSEG_LEN;
405 continue;
406
407 case TCPOPT_WSCALE:
408 if (len < TCPOPT_WS_LEN || up[1] != TCPOPT_WS_LEN)
409 break;
410
411 if (up[2] > TCP_MAX_WINSHIFT)
412 tcpopt->tcp_opt_wscale = TCP_MAX_WINSHIFT;
413 else
414 tcpopt->tcp_opt_wscale = up[2];
415 found |= TCP_OPT_WSCALE_PRESENT;
416
417 up += TCPOPT_WS_LEN;
418 continue;
419
420 case TCPOPT_SACK_PERMITTED:
421 if (len < TCPOPT_SACK_OK_LEN ||
422 up[1] != TCPOPT_SACK_OK_LEN)
423 break;
424 found |= TCP_OPT_SACK_OK_PRESENT;
425 up += TCPOPT_SACK_OK_LEN;
426 continue;
427
428 case TCPOPT_SACK:
429 if (len <= 2 || up[1] <= 2 || len < up[1])
430 break;
431
432 /* If TCP is not interested in SACK blks... */
433 if ((tcp = tcpopt->tcp) == NULL) {
434 up += up[1];
435 continue;
436 }
437 sack_len = up[1] - TCPOPT_HEADER_LEN;
438 up += TCPOPT_HEADER_LEN;
439
440 /*
441 * If the list is empty, allocate one and assume
442 * nothing is sack'ed.
443 */
444 if (tcp->tcp_notsack_list == NULL) {
445 tcp_notsack_update(&(tcp->tcp_notsack_list),
446 tcp->tcp_suna, tcp->tcp_snxt,
447 &(tcp->tcp_num_notsack_blk),
448 &(tcp->tcp_cnt_notsack_list));
449
450 /*
451 * Make sure tcp_notsack_list is not NULL.
452 * This happens when kmem_alloc(KM_NOSLEEP)
453 * returns NULL.
454 */
455 if (tcp->tcp_notsack_list == NULL) {
456 up += sack_len;
457 continue;
458 }
459 tcp->tcp_fack = tcp->tcp_suna;
460 }
461
462 while (sack_len > 0) {
463 if (up + 8 > endp) {
464 up = endp;
465 break;
466 }
467 sack_begin = BE32_TO_U32(up);
468 up += 4;
469 sack_end = BE32_TO_U32(up);
470 up += 4;
471 sack_len -= 8;
472 /*
473 * Bounds checking. Make sure the SACK
474 * info is within tcp_suna and tcp_snxt.
475 * If this SACK blk is out of bound, ignore
476 * it but continue to parse the following
477 * blks.
478 */
479 if (SEQ_LEQ(sack_end, sack_begin) ||
480 SEQ_LT(sack_begin, tcp->tcp_suna) ||
481 SEQ_GT(sack_end, tcp->tcp_snxt)) {
482 continue;
483 }
484 tcp_notsack_insert(&(tcp->tcp_notsack_list),
485 sack_begin, sack_end,
486 &(tcp->tcp_num_notsack_blk),
487 &(tcp->tcp_cnt_notsack_list));
488 if (SEQ_GT(sack_end, tcp->tcp_fack)) {
489 tcp->tcp_fack = sack_end;
490 }
491 }
492 found |= TCP_OPT_SACK_PRESENT;
493 continue;
494
495 case TCPOPT_TSTAMP:
496 if (len < TCPOPT_TSTAMP_LEN ||
497 up[1] != TCPOPT_TSTAMP_LEN)
498 break;
499
500 tcpopt->tcp_opt_ts_val = BE32_TO_U32(up+2);
501 tcpopt->tcp_opt_ts_ecr = BE32_TO_U32(up+6);
502
503 found |= TCP_OPT_TSTAMP_PRESENT;
504
505 up += TCPOPT_TSTAMP_LEN;
506 continue;
507
508 default:
509 if (len <= 1 || len < (int)up[1] || up[1] == 0)
510 break;
511 up += up[1];
512 continue;
513 }
514 break;
515 }
516 return (found);
517 }
518
519 /*
520 * Process all TCP option in SYN segment. Note that this function should
521 * be called after tcp_set_destination() is called so that the necessary info
522 * from IRE is already set in the tcp structure.
523 *
524 * This function sets up the correct tcp_mss value according to the
525 * MSS option value and our header size. It also sets up the window scale
526 * and timestamp values, and initialize SACK info blocks. But it does not
527 * change receive window size after setting the tcp_mss value. The caller
528 * should do the appropriate change.
529 */
530 static void
531 tcp_process_options(tcp_t *tcp, tcpha_t *tcpha)
532 {
533 int options;
534 tcp_opt_t tcpopt;
535 uint32_t mss_max;
536 char *tmp_tcph;
537 tcp_stack_t *tcps = tcp->tcp_tcps;
538 conn_t *connp = tcp->tcp_connp;
539
540 tcpopt.tcp = NULL;
541 options = tcp_parse_options(tcpha, &tcpopt);
542
543 /*
544 * Process MSS option. Note that MSS option value does not account
545 * for IP or TCP options. This means that it is equal to MTU - minimum
546 * IP+TCP header size, which is 40 bytes for IPv4 and 60 bytes for
547 * IPv6.
548 */
549 if (!(options & TCP_OPT_MSS_PRESENT)) {
550 if (connp->conn_ipversion == IPV4_VERSION)
551 tcpopt.tcp_opt_mss = tcps->tcps_mss_def_ipv4;
552 else
553 tcpopt.tcp_opt_mss = tcps->tcps_mss_def_ipv6;
554 } else {
555 if (connp->conn_ipversion == IPV4_VERSION)
556 mss_max = tcps->tcps_mss_max_ipv4;
557 else
558 mss_max = tcps->tcps_mss_max_ipv6;
559 if (tcpopt.tcp_opt_mss < tcps->tcps_mss_min)
560 tcpopt.tcp_opt_mss = tcps->tcps_mss_min;
561 else if (tcpopt.tcp_opt_mss > mss_max)
562 tcpopt.tcp_opt_mss = mss_max;
563 }
564
565 /* Process Window Scale option. */
566 if (options & TCP_OPT_WSCALE_PRESENT) {
567 tcp->tcp_snd_ws = tcpopt.tcp_opt_wscale;
568 tcp->tcp_snd_ws_ok = B_TRUE;
569 } else {
570 tcp->tcp_snd_ws = B_FALSE;
571 tcp->tcp_snd_ws_ok = B_FALSE;
572 tcp->tcp_rcv_ws = B_FALSE;
573 }
574
575 /* Process Timestamp option. */
576 if ((options & TCP_OPT_TSTAMP_PRESENT) &&
577 (tcp->tcp_snd_ts_ok || TCP_IS_DETACHED(tcp))) {
578 tmp_tcph = (char *)tcp->tcp_tcpha;
579
580 tcp->tcp_snd_ts_ok = B_TRUE;
581 tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val;
582 tcp->tcp_last_rcv_lbolt = ddi_get_lbolt64();
583 ASSERT(OK_32PTR(tmp_tcph));
584 ASSERT(connp->conn_ht_ulp_len == TCP_MIN_HEADER_LENGTH);
585
586 /* Fill in our template header with basic timestamp option. */
587 tmp_tcph += connp->conn_ht_ulp_len;
588 tmp_tcph[0] = TCPOPT_NOP;
589 tmp_tcph[1] = TCPOPT_NOP;
590 tmp_tcph[2] = TCPOPT_TSTAMP;
591 tmp_tcph[3] = TCPOPT_TSTAMP_LEN;
592 connp->conn_ht_iphc_len += TCPOPT_REAL_TS_LEN;
593 connp->conn_ht_ulp_len += TCPOPT_REAL_TS_LEN;
594 tcp->tcp_tcpha->tha_offset_and_reserved += (3 << 4);
595 } else {
596 tcp->tcp_snd_ts_ok = B_FALSE;
597 }
598
599 /*
600 * Process SACK options. If SACK is enabled for this connection,
601 * then allocate the SACK info structure. Note the following ways
602 * when tcp_snd_sack_ok is set to true.
603 *
604 * For active connection: in tcp_set_destination() called in
605 * tcp_connect().
606 *
607 * For passive connection: in tcp_set_destination() called in
608 * tcp_input_listener().
609 *
610 * That's the reason why the extra TCP_IS_DETACHED() check is there.
611 * That check makes sure that if we did not send a SACK OK option,
612 * we will not enable SACK for this connection even though the other
613 * side sends us SACK OK option. For active connection, the SACK
614 * info structure has already been allocated. So we need to free
615 * it if SACK is disabled.
616 */
617 if ((options & TCP_OPT_SACK_OK_PRESENT) &&
618 (tcp->tcp_snd_sack_ok ||
619 (tcps->tcps_sack_permitted != 0 && TCP_IS_DETACHED(tcp)))) {
620 ASSERT(tcp->tcp_num_sack_blk == 0);
621 ASSERT(tcp->tcp_notsack_list == NULL);
622
623 tcp->tcp_snd_sack_ok = B_TRUE;
624 if (tcp->tcp_snd_ts_ok) {
625 tcp->tcp_max_sack_blk = 3;
626 } else {
627 tcp->tcp_max_sack_blk = 4;
628 }
629 } else if (tcp->tcp_snd_sack_ok) {
630 /*
631 * Resetting tcp_snd_sack_ok to B_FALSE so that
632 * no SACK info will be used for this
633 * connection. This assumes that SACK usage
634 * permission is negotiated. This may need
635 * to be changed once this is clarified.
636 */
637 ASSERT(tcp->tcp_num_sack_blk == 0);
638 ASSERT(tcp->tcp_notsack_list == NULL);
639 tcp->tcp_snd_sack_ok = B_FALSE;
640 }
641
642 /*
643 * Now we know the exact TCP/IP header length, subtract
644 * that from tcp_mss to get our side's MSS.
645 */
646 tcp->tcp_mss -= connp->conn_ht_iphc_len;
647
648 /*
649 * Here we assume that the other side's header size will be equal to
650 * our header size. We calculate the real MSS accordingly. Need to
651 * take into additional stuffs IPsec puts in.
652 *
653 * Real MSS = Opt.MSS - (our TCP/IP header - min TCP/IP header)
654 */
655 tcpopt.tcp_opt_mss -= connp->conn_ht_iphc_len +
656 tcp->tcp_ipsec_overhead -
657 ((connp->conn_ipversion == IPV4_VERSION ?
658 IP_SIMPLE_HDR_LENGTH : IPV6_HDR_LEN) + TCP_MIN_HEADER_LENGTH);
659
660 /*
661 * Set MSS to the smaller one of both ends of the connection.
662 * We should not have called tcp_mss_set() before, but our
663 * side of the MSS should have been set to a proper value
664 * by tcp_set_destination(). tcp_mss_set() will also set up the
665 * STREAM head parameters properly.
666 *
667 * If we have a larger-than-16-bit window but the other side
668 * didn't want to do window scale, tcp_rwnd_set() will take
669 * care of that.
670 */
671 tcp_mss_set(tcp, MIN(tcpopt.tcp_opt_mss, tcp->tcp_mss));
672
673 /*
674 * Initialize tcp_cwnd value. After tcp_mss_set(), tcp_mss has been
675 * updated properly.
676 */
677 TCP_SET_INIT_CWND(tcp, tcp->tcp_mss, tcps->tcps_slow_start_initial);
678
679 if (tcp->tcp_cc_algo->conn_init != NULL)
680 tcp->tcp_cc_algo->conn_init(&tcp->tcp_ccv);
681 }
682
683 /*
684 * Add a new piece to the tcp reassembly queue. If the gap at the beginning
685 * is filled, return as much as we can. The message passed in may be
686 * multi-part, chained using b_cont. "start" is the starting sequence
687 * number for this piece.
688 */
689 static mblk_t *
690 tcp_reass(tcp_t *tcp, mblk_t *mp, uint32_t start)
691 {
692 uint32_t end, bytes;
693 mblk_t *mp1;
694 mblk_t *mp2;
695 mblk_t *next_mp;
696 uint32_t u1;
697 tcp_stack_t *tcps = tcp->tcp_tcps;
698
699
700 /* Walk through all the new pieces. */
701 do {
702 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
703 (uintptr_t)INT_MAX);
704 end = start + (int)(mp->b_wptr - mp->b_rptr);
705 next_mp = mp->b_cont;
706 if (start == end) {
707 /* Empty. Blast it. */
708 freeb(mp);
709 continue;
710 }
711 bytes = end - start;
712 mp->b_cont = NULL;
713 TCP_REASS_SET_SEQ(mp, start);
714 TCP_REASS_SET_END(mp, end);
715 mp1 = tcp->tcp_reass_tail;
716 if (mp1 == NULL || SEQ_GEQ(start, TCP_REASS_END(mp1))) {
717 if (mp1 != NULL) {
718 /*
719 * New stuff is beyond the tail; link it on the
720 * end.
721 */
722 mp1->b_cont = mp;
723 } else {
724 tcp->tcp_reass_head = mp;
725 }
726 tcp->tcp_reass_tail = mp;
727 TCPS_BUMP_MIB(tcps, tcpInDataUnorderSegs);
728 TCPS_UPDATE_MIB(tcps, tcpInDataUnorderBytes, bytes);
729 tcp->tcp_cs.tcp_in_data_unorder_segs++;
730 tcp->tcp_cs.tcp_in_data_unorder_bytes += bytes;
731 continue;
732 }
733 mp1 = tcp->tcp_reass_head;
734 u1 = TCP_REASS_SEQ(mp1);
735 /* New stuff at the front? */
736 if (SEQ_LT(start, u1)) {
737 /* Yes... Check for overlap. */
738 mp->b_cont = mp1;
739 tcp->tcp_reass_head = mp;
740 tcp_reass_elim_overlap(tcp, mp);
741 continue;
742 }
743 /*
744 * The new piece fits somewhere between the head and tail.
745 * We find our slot, where mp1 precedes us and mp2 trails.
746 */
747 for (; (mp2 = mp1->b_cont) != NULL; mp1 = mp2) {
748 u1 = TCP_REASS_SEQ(mp2);
749 if (SEQ_LEQ(start, u1))
750 break;
751 }
752 /* Link ourselves in */
753 mp->b_cont = mp2;
754 mp1->b_cont = mp;
755
756 /* Trim overlap with following mblk(s) first */
757 tcp_reass_elim_overlap(tcp, mp);
758
759 /* Trim overlap with preceding mblk */
760 tcp_reass_elim_overlap(tcp, mp1);
761
762 } while (start = end, mp = next_mp);
763 mp1 = tcp->tcp_reass_head;
764 /* Anything ready to go? */
765 if (TCP_REASS_SEQ(mp1) != tcp->tcp_rnxt)
766 return (NULL);
767 /* Eat what we can off the queue */
768 for (;;) {
769 mp = mp1->b_cont;
770 end = TCP_REASS_END(mp1);
771 TCP_REASS_SET_SEQ(mp1, 0);
772 TCP_REASS_SET_END(mp1, 0);
773 if (!mp) {
774 tcp->tcp_reass_tail = NULL;
775 break;
776 }
777 if (end != TCP_REASS_SEQ(mp)) {
778 mp1->b_cont = NULL;
779 break;
780 }
781 mp1 = mp;
782 }
783 mp1 = tcp->tcp_reass_head;
784 tcp->tcp_reass_head = mp;
785 return (mp1);
786 }
787
788 /* Eliminate any overlap that mp may have over later mblks */
789 static void
790 tcp_reass_elim_overlap(tcp_t *tcp, mblk_t *mp)
791 {
792 uint32_t end;
793 mblk_t *mp1;
794 uint32_t u1;
795 tcp_stack_t *tcps = tcp->tcp_tcps;
796
797 end = TCP_REASS_END(mp);
798 while ((mp1 = mp->b_cont) != NULL) {
799 u1 = TCP_REASS_SEQ(mp1);
800 if (!SEQ_GT(end, u1))
801 break;
802 if (!SEQ_GEQ(end, TCP_REASS_END(mp1))) {
803 mp->b_wptr -= end - u1;
804 TCP_REASS_SET_END(mp, u1);
805 TCPS_BUMP_MIB(tcps, tcpInDataPartDupSegs);
806 TCPS_UPDATE_MIB(tcps, tcpInDataPartDupBytes,
807 end - u1);
808 break;
809 }
810 mp->b_cont = mp1->b_cont;
811 TCP_REASS_SET_SEQ(mp1, 0);
812 TCP_REASS_SET_END(mp1, 0);
813 freeb(mp1);
814 TCPS_BUMP_MIB(tcps, tcpInDataDupSegs);
815 TCPS_UPDATE_MIB(tcps, tcpInDataDupBytes, end - u1);
816 }
817 if (!mp1)
818 tcp->tcp_reass_tail = mp;
819 }
820
821 /*
822 * This function does PAWS protection check, per RFC 7323 section 5. Requires
823 * that timestamp options are already processed into tcpoptp. Returns B_TRUE if
824 * the segment passes the PAWS test, else returns B_FALSE.
825 */
826 boolean_t
827 tcp_paws_check(tcp_t *tcp, const tcp_opt_t *tcpoptp)
828 {
829 if (TSTMP_LT(tcpoptp->tcp_opt_ts_val,
830 tcp->tcp_ts_recent)) {
831 if (LBOLT_FASTPATH64 <
832 (tcp->tcp_last_rcv_lbolt + PAWS_TIMEOUT)) {
833 /* This segment is not acceptable. */
834 return (B_FALSE);
835 } else {
836 /*
837 * Connection has been idle for
838 * too long. Reset the timestamp
839 */
840 tcp->tcp_ts_recent =
841 tcpoptp->tcp_opt_ts_val;
842 }
843 }
844 return (B_TRUE);
845 }
846
847 /*
848 * Defense for the SYN attack -
849 * 1. When q0 is full, drop from the tail (tcp_eager_prev_drop_q0) the oldest
850 * one from the list of droppable eagers. This list is a subset of q0.
851 * see comments before the definition of MAKE_DROPPABLE().
852 * 2. Don't drop a SYN request before its first timeout. This gives every
853 * request at least til the first timeout to complete its 3-way handshake.
854 * 3. Maintain tcp_syn_rcvd_timeout as an accurate count of how many
855 * requests currently on the queue that has timed out. This will be used
856 * as an indicator of whether an attack is under way, so that appropriate
857 * actions can be taken. (It's incremented in tcp_timer() and decremented
858 * either when eager goes into ESTABLISHED, or gets freed up.)
859 * 4. The current threshold is - # of timeout > q0len/4 => SYN alert on
860 * # of timeout drops back to <= q0len/32 => SYN alert off
861 */
862 static boolean_t
863 tcp_drop_q0(tcp_t *tcp)
864 {
865 tcp_t *eager;
866 mblk_t *mp;
867 tcp_stack_t *tcps = tcp->tcp_tcps;
868
869 ASSERT(MUTEX_HELD(&tcp->tcp_eager_lock));
870 ASSERT(tcp->tcp_eager_next_q0 != tcp->tcp_eager_prev_q0);
871
872 /* Pick oldest eager from the list of droppable eagers */
873 eager = tcp->tcp_eager_prev_drop_q0;
874
875 /* If list is empty. return B_FALSE */
876 if (eager == tcp) {
877 return (B_FALSE);
878 }
879
880 /* If allocated, the mp will be freed in tcp_clean_death_wrapper() */
881 if ((mp = allocb(0, BPRI_HI)) == NULL)
882 return (B_FALSE);
883
884 /*
885 * Take this eager out from the list of droppable eagers since we are
886 * going to drop it.
887 */
888 MAKE_UNDROPPABLE(eager);
889
890 if (tcp->tcp_connp->conn_debug) {
891 (void) strlog(TCP_MOD_ID, 0, 3, SL_TRACE,
892 "tcp_drop_q0: listen half-open queue (max=%d) overflow"
893 " (%d pending) on %s, drop one", tcps->tcps_conn_req_max_q0,
894 tcp->tcp_conn_req_cnt_q0,
895 tcp_display(tcp, NULL, DISP_PORT_ONLY));
896 }
897
898 TCPS_BUMP_MIB(tcps, tcpHalfOpenDrop);
899
900 /* Put a reference on the conn as we are enqueueing it in the sqeue */
901 CONN_INC_REF(eager->tcp_connp);
902
903 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
904 tcp_clean_death_wrapper, eager->tcp_connp, NULL,
905 SQ_FILL, SQTAG_TCP_DROP_Q0);
906
907 return (B_TRUE);
908 }
909
910 /*
911 * Handle a SYN on an AF_INET6 socket; can be either IPv4 or IPv6
912 */
913 static mblk_t *
914 tcp_conn_create_v6(conn_t *lconnp, conn_t *connp, mblk_t *mp,
915 ip_recv_attr_t *ira)
916 {
917 tcp_t *ltcp = lconnp->conn_tcp;
918 tcp_t *tcp = connp->conn_tcp;
919 mblk_t *tpi_mp;
920 ipha_t *ipha;
921 ip6_t *ip6h;
922 sin6_t sin6;
923 uint_t ifindex = ira->ira_ruifindex;
924 tcp_stack_t *tcps = tcp->tcp_tcps;
925
926 if (ira->ira_flags & IRAF_IS_IPV4) {
927 ipha = (ipha_t *)mp->b_rptr;
928
929 connp->conn_ipversion = IPV4_VERSION;
930 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_dst, &connp->conn_laddr_v6);
931 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_src, &connp->conn_faddr_v6);
932 connp->conn_saddr_v6 = connp->conn_laddr_v6;
933
934 sin6 = sin6_null;
935 sin6.sin6_addr = connp->conn_faddr_v6;
936 sin6.sin6_port = connp->conn_fport;
937 sin6.sin6_family = AF_INET6;
938 sin6.__sin6_src_id = ip_srcid_find_addr(&connp->conn_laddr_v6,
939 IPCL_ZONEID(lconnp), tcps->tcps_netstack);
940
941 if (connp->conn_recv_ancillary.crb_recvdstaddr) {
942 sin6_t sin6d;
943
944 sin6d = sin6_null;
945 sin6d.sin6_addr = connp->conn_laddr_v6;
946 sin6d.sin6_port = connp->conn_lport;
947 sin6d.sin6_family = AF_INET;
948 tpi_mp = mi_tpi_extconn_ind(NULL,
949 (char *)&sin6d, sizeof (sin6_t),
950 (char *)&tcp,
951 (t_scalar_t)sizeof (intptr_t),
952 (char *)&sin6d, sizeof (sin6_t),
953 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
954 } else {
955 tpi_mp = mi_tpi_conn_ind(NULL,
956 (char *)&sin6, sizeof (sin6_t),
957 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
958 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
959 }
960 } else {
961 ip6h = (ip6_t *)mp->b_rptr;
962
963 connp->conn_ipversion = IPV6_VERSION;
964 connp->conn_laddr_v6 = ip6h->ip6_dst;
965 connp->conn_faddr_v6 = ip6h->ip6_src;
966 connp->conn_saddr_v6 = connp->conn_laddr_v6;
967
968 sin6 = sin6_null;
969 sin6.sin6_addr = connp->conn_faddr_v6;
970 sin6.sin6_port = connp->conn_fport;
971 sin6.sin6_family = AF_INET6;
972 sin6.sin6_flowinfo = ip6h->ip6_vcf & ~IPV6_VERS_AND_FLOW_MASK;
973 sin6.__sin6_src_id = ip_srcid_find_addr(&connp->conn_laddr_v6,
974 IPCL_ZONEID(lconnp), tcps->tcps_netstack);
975
976 if (IN6_IS_ADDR_LINKSCOPE(&ip6h->ip6_src)) {
977 /* Pass up the scope_id of remote addr */
978 sin6.sin6_scope_id = ifindex;
979 } else {
980 sin6.sin6_scope_id = 0;
981 }
982 if (connp->conn_recv_ancillary.crb_recvdstaddr) {
983 sin6_t sin6d;
984
985 sin6d = sin6_null;
986 sin6.sin6_addr = connp->conn_laddr_v6;
987 sin6d.sin6_port = connp->conn_lport;
988 sin6d.sin6_family = AF_INET6;
989 if (IN6_IS_ADDR_LINKSCOPE(&connp->conn_laddr_v6))
990 sin6d.sin6_scope_id = ifindex;
991
992 tpi_mp = mi_tpi_extconn_ind(NULL,
993 (char *)&sin6d, sizeof (sin6_t),
994 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
995 (char *)&sin6d, sizeof (sin6_t),
996 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
997 } else {
998 tpi_mp = mi_tpi_conn_ind(NULL,
999 (char *)&sin6, sizeof (sin6_t),
1000 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
1001 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
1002 }
1003 }
1004
1005 tcp->tcp_mss = tcps->tcps_mss_def_ipv6;
1006 return (tpi_mp);
1007 }
1008
1009 /* Handle a SYN on an AF_INET socket */
1010 static mblk_t *
1011 tcp_conn_create_v4(conn_t *lconnp, conn_t *connp, mblk_t *mp,
1012 ip_recv_attr_t *ira)
1013 {
1014 tcp_t *ltcp = lconnp->conn_tcp;
1015 tcp_t *tcp = connp->conn_tcp;
1016 sin_t sin;
1017 mblk_t *tpi_mp = NULL;
1018 tcp_stack_t *tcps = tcp->tcp_tcps;
1019 ipha_t *ipha;
1020
1021 ASSERT(ira->ira_flags & IRAF_IS_IPV4);
1022 ipha = (ipha_t *)mp->b_rptr;
1023
1024 connp->conn_ipversion = IPV4_VERSION;
1025 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_dst, &connp->conn_laddr_v6);
1026 IN6_IPADDR_TO_V4MAPPED(ipha->ipha_src, &connp->conn_faddr_v6);
1027 connp->conn_saddr_v6 = connp->conn_laddr_v6;
1028
1029 sin = sin_null;
1030 sin.sin_addr.s_addr = connp->conn_faddr_v4;
1031 sin.sin_port = connp->conn_fport;
1032 sin.sin_family = AF_INET;
1033 if (lconnp->conn_recv_ancillary.crb_recvdstaddr) {
1034 sin_t sind;
1035
1036 sind = sin_null;
1037 sind.sin_addr.s_addr = connp->conn_laddr_v4;
1038 sind.sin_port = connp->conn_lport;
1039 sind.sin_family = AF_INET;
1040 tpi_mp = mi_tpi_extconn_ind(NULL,
1041 (char *)&sind, sizeof (sin_t), (char *)&tcp,
1042 (t_scalar_t)sizeof (intptr_t), (char *)&sind,
1043 sizeof (sin_t), (t_scalar_t)ltcp->tcp_conn_req_seqnum);
1044 } else {
1045 tpi_mp = mi_tpi_conn_ind(NULL,
1046 (char *)&sin, sizeof (sin_t),
1047 (char *)&tcp, (t_scalar_t)sizeof (intptr_t),
1048 (t_scalar_t)ltcp->tcp_conn_req_seqnum);
1049 }
1050
1051 tcp->tcp_mss = tcps->tcps_mss_def_ipv4;
1052 return (tpi_mp);
1053 }
1054
1055 /*
1056 * Called via squeue to get on to eager's perimeter. It sends a
1057 * TH_RST if eager is in the fanout table. The listener wants the
1058 * eager to disappear either by means of tcp_eager_blowoff() or
1059 * tcp_eager_cleanup() being called. tcp_eager_kill() can also be
1060 * called (via squeue) if the eager cannot be inserted in the
1061 * fanout table in tcp_input_listener().
1062 */
1063 /* ARGSUSED */
1064 void
1065 tcp_eager_kill(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1066 {
1067 conn_t *econnp = (conn_t *)arg;
1068 tcp_t *eager = econnp->conn_tcp;
1069 tcp_t *listener = eager->tcp_listener;
1070
1071 /*
1072 * We could be called because listener is closing. Since
1073 * the eager was using listener's queue's, we avoid
1074 * using the listeners queues from now on.
1075 */
1076 ASSERT(eager->tcp_detached);
1077 econnp->conn_rq = NULL;
1078 econnp->conn_wq = NULL;
1079
1080 /*
1081 * An eager's conn_fanout will be NULL if it's a duplicate
1082 * for an existing 4-tuples in the conn fanout table.
1083 * We don't want to send an RST out in such case.
1084 */
1085 if (econnp->conn_fanout != NULL && eager->tcp_state > TCPS_LISTEN) {
1086 tcp_xmit_ctl("tcp_eager_kill, can't wait",
1087 eager, eager->tcp_snxt, 0, TH_RST);
1088 }
1089
1090 /* We are here because listener wants this eager gone */
1091 if (listener != NULL) {
1092 mutex_enter(&listener->tcp_eager_lock);
1093 tcp_eager_unlink(eager);
1094 if (eager->tcp_tconnind_started) {
1095 /*
1096 * The eager has sent a conn_ind up to the
1097 * listener but listener decides to close
1098 * instead. We need to drop the extra ref
1099 * placed on eager in tcp_input_data() before
1100 * sending the conn_ind to listener.
1101 */
1102 CONN_DEC_REF(econnp);
1103 }
1104 mutex_exit(&listener->tcp_eager_lock);
1105 CONN_DEC_REF(listener->tcp_connp);
1106 }
1107
1108 if (eager->tcp_state != TCPS_CLOSED)
1109 tcp_close_detached(eager);
1110 }
1111
1112 /*
1113 * Reset any eager connection hanging off this listener marked
1114 * with 'seqnum' and then reclaim it's resources.
1115 */
1116 boolean_t
1117 tcp_eager_blowoff(tcp_t *listener, t_scalar_t seqnum)
1118 {
1119 tcp_t *eager;
1120 mblk_t *mp;
1121
1122 eager = listener;
1123 mutex_enter(&listener->tcp_eager_lock);
1124 do {
1125 eager = eager->tcp_eager_next_q;
1126 if (eager == NULL) {
1127 mutex_exit(&listener->tcp_eager_lock);
1128 return (B_FALSE);
1129 }
1130 } while (eager->tcp_conn_req_seqnum != seqnum);
1131
1132 if (eager->tcp_closemp_used) {
1133 mutex_exit(&listener->tcp_eager_lock);
1134 return (B_TRUE);
1135 }
1136 eager->tcp_closemp_used = B_TRUE;
1137 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1138 CONN_INC_REF(eager->tcp_connp);
1139 mutex_exit(&listener->tcp_eager_lock);
1140 mp = &eager->tcp_closemp;
1141 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp, tcp_eager_kill,
1142 eager->tcp_connp, NULL, SQ_FILL, SQTAG_TCP_EAGER_BLOWOFF);
1143 return (B_TRUE);
1144 }
1145
1146 /*
1147 * Reset any eager connection hanging off this listener
1148 * and then reclaim it's resources.
1149 */
1150 void
1151 tcp_eager_cleanup(tcp_t *listener, boolean_t q0_only)
1152 {
1153 tcp_t *eager;
1154 mblk_t *mp;
1155 tcp_stack_t *tcps = listener->tcp_tcps;
1156
1157 ASSERT(MUTEX_HELD(&listener->tcp_eager_lock));
1158
1159 if (!q0_only) {
1160 /* First cleanup q */
1161 TCP_STAT(tcps, tcp_eager_blowoff_q);
1162 eager = listener->tcp_eager_next_q;
1163 while (eager != NULL) {
1164 if (!eager->tcp_closemp_used) {
1165 eager->tcp_closemp_used = B_TRUE;
1166 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1167 CONN_INC_REF(eager->tcp_connp);
1168 mp = &eager->tcp_closemp;
1169 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
1170 tcp_eager_kill, eager->tcp_connp, NULL,
1171 SQ_FILL, SQTAG_TCP_EAGER_CLEANUP);
1172 }
1173 eager = eager->tcp_eager_next_q;
1174 }
1175 }
1176 /* Then cleanup q0 */
1177 TCP_STAT(tcps, tcp_eager_blowoff_q0);
1178 eager = listener->tcp_eager_next_q0;
1179 while (eager != listener) {
1180 if (!eager->tcp_closemp_used) {
1181 eager->tcp_closemp_used = B_TRUE;
1182 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1183 CONN_INC_REF(eager->tcp_connp);
1184 mp = &eager->tcp_closemp;
1185 SQUEUE_ENTER_ONE(eager->tcp_connp->conn_sqp, mp,
1186 tcp_eager_kill, eager->tcp_connp, NULL, SQ_FILL,
1187 SQTAG_TCP_EAGER_CLEANUP_Q0);
1188 }
1189 eager = eager->tcp_eager_next_q0;
1190 }
1191 }
1192
1193 /*
1194 * If we are an eager connection hanging off a listener that hasn't
1195 * formally accepted the connection yet, get off its list and blow off
1196 * any data that we have accumulated.
1197 */
1198 void
1199 tcp_eager_unlink(tcp_t *tcp)
1200 {
1201 tcp_t *listener = tcp->tcp_listener;
1202
1203 ASSERT(listener != NULL);
1204 ASSERT(MUTEX_HELD(&listener->tcp_eager_lock));
1205 if (tcp->tcp_eager_next_q0 != NULL) {
1206 ASSERT(tcp->tcp_eager_prev_q0 != NULL);
1207
1208 /* Remove the eager tcp from q0 */
1209 tcp->tcp_eager_next_q0->tcp_eager_prev_q0 =
1210 tcp->tcp_eager_prev_q0;
1211 tcp->tcp_eager_prev_q0->tcp_eager_next_q0 =
1212 tcp->tcp_eager_next_q0;
1213 ASSERT(listener->tcp_conn_req_cnt_q0 > 0);
1214 listener->tcp_conn_req_cnt_q0--;
1215
1216 tcp->tcp_eager_next_q0 = NULL;
1217 tcp->tcp_eager_prev_q0 = NULL;
1218
1219 /*
1220 * Take the eager out, if it is in the list of droppable
1221 * eagers.
1222 */
1223 MAKE_UNDROPPABLE(tcp);
1224
1225 if (tcp->tcp_syn_rcvd_timeout != 0) {
1226 /* we have timed out before */
1227 ASSERT(listener->tcp_syn_rcvd_timeout > 0);
1228 listener->tcp_syn_rcvd_timeout--;
1229 }
1230 } else {
1231 tcp_t **tcpp = &listener->tcp_eager_next_q;
1232 tcp_t *prev = NULL;
1233
1234 for (; tcpp[0]; tcpp = &tcpp[0]->tcp_eager_next_q) {
1235 if (tcpp[0] == tcp) {
1236 if (listener->tcp_eager_last_q == tcp) {
1237 /*
1238 * If we are unlinking the last
1239 * element on the list, adjust
1240 * tail pointer. Set tail pointer
1241 * to nil when list is empty.
1242 */
1243 ASSERT(tcp->tcp_eager_next_q == NULL);
1244 if (listener->tcp_eager_last_q ==
1245 listener->tcp_eager_next_q) {
1246 listener->tcp_eager_last_q =
1247 NULL;
1248 } else {
1249 /*
1250 * We won't get here if there
1251 * is only one eager in the
1252 * list.
1253 */
1254 ASSERT(prev != NULL);
1255 listener->tcp_eager_last_q =
1256 prev;
1257 }
1258 }
1259 tcpp[0] = tcp->tcp_eager_next_q;
1260 tcp->tcp_eager_next_q = NULL;
1261 tcp->tcp_eager_last_q = NULL;
1262 ASSERT(listener->tcp_conn_req_cnt_q > 0);
1263 listener->tcp_conn_req_cnt_q--;
1264 break;
1265 }
1266 prev = tcpp[0];
1267 }
1268 }
1269 tcp->tcp_listener = NULL;
1270 }
1271
1272 /* BEGIN CSTYLED */
1273 /*
1274 *
1275 * The sockfs ACCEPT path:
1276 * =======================
1277 *
1278 * The eager is now established in its own perimeter as soon as SYN is
1279 * received in tcp_input_listener(). When sockfs receives conn_ind, it
1280 * completes the accept processing on the acceptor STREAM. The sending
1281 * of conn_ind part is common for both sockfs listener and a TLI/XTI
1282 * listener but a TLI/XTI listener completes the accept processing
1283 * on the listener perimeter.
1284 *
1285 * Common control flow for 3 way handshake:
1286 * ----------------------------------------
1287 *
1288 * incoming SYN (listener perimeter) -> tcp_input_listener()
1289 *
1290 * incoming SYN-ACK-ACK (eager perim) -> tcp_input_data()
1291 * send T_CONN_IND (listener perim) -> tcp_send_conn_ind()
1292 *
1293 * Sockfs ACCEPT Path:
1294 * -------------------
1295 *
1296 * open acceptor stream (tcp_open allocates tcp_tli_accept()
1297 * as STREAM entry point)
1298 *
1299 * soaccept() sends T_CONN_RES on the acceptor STREAM to tcp_tli_accept()
1300 *
1301 * tcp_tli_accept() extracts the eager and makes the q->q_ptr <-> eager
1302 * association (we are not behind eager's squeue but sockfs is protecting us
1303 * and no one knows about this stream yet. The STREAMS entry point q->q_info
1304 * is changed to point at tcp_wput().
1305 *
1306 * tcp_accept_common() sends any deferred eagers via tcp_send_pending() to
1307 * listener (done on listener's perimeter).
1308 *
1309 * tcp_tli_accept() calls tcp_accept_finish() on eagers perimeter to finish
1310 * accept.
1311 *
1312 * TLI/XTI client ACCEPT path:
1313 * ---------------------------
1314 *
1315 * soaccept() sends T_CONN_RES on the listener STREAM.
1316 *
1317 * tcp_tli_accept() -> tcp_accept_swap() complete the processing and send
1318 * a M_SETOPS mblk to eager perimeter to finish accept (tcp_accept_finish()).
1319 *
1320 * Locks:
1321 * ======
1322 *
1323 * listener->tcp_eager_lock protects the listeners->tcp_eager_next_q0 and
1324 * and listeners->tcp_eager_next_q.
1325 *
1326 * Referencing:
1327 * ============
1328 *
1329 * 1) We start out in tcp_input_listener by eager placing a ref on
1330 * listener and listener adding eager to listeners->tcp_eager_next_q0.
1331 *
1332 * 2) When a SYN-ACK-ACK arrives, we send the conn_ind to listener. Before
1333 * doing so we place a ref on the eager. This ref is finally dropped at the
1334 * end of tcp_accept_finish() while unwinding from the squeue, i.e. the
1335 * reference is dropped by the squeue framework.
1336 *
1337 * 3) The ref on listener placed in 1 above is dropped in tcp_accept_finish
1338 *
1339 * The reference must be released by the same entity that added the reference
1340 * In the above scheme, the eager is the entity that adds and releases the
1341 * references. Note that tcp_accept_finish executes in the squeue of the eager
1342 * (albeit after it is attached to the acceptor stream). Though 1. executes
1343 * in the listener's squeue, the eager is nascent at this point and the
1344 * reference can be considered to have been added on behalf of the eager.
1345 *
1346 * Eager getting a Reset or listener closing:
1347 * ==========================================
1348 *
1349 * Once the listener and eager are linked, the listener never does the unlink.
1350 * If the listener needs to close, tcp_eager_cleanup() is called which queues
1351 * a message on all eager perimeter. The eager then does the unlink, clears
1352 * any pointers to the listener's queue and drops the reference to the
1353 * listener. The listener waits in tcp_close outside the squeue until its
1354 * refcount has dropped to 1. This ensures that the listener has waited for
1355 * all eagers to clear their association with the listener.
1356 *
1357 * Similarly, if eager decides to go away, it can unlink itself and close.
1358 * When the T_CONN_RES comes down, we check if eager has closed. Note that
1359 * the reference to eager is still valid because of the extra ref we put
1360 * in tcp_send_conn_ind.
1361 *
1362 * Listener can always locate the eager under the protection
1363 * of the listener->tcp_eager_lock, and then do a refhold
1364 * on the eager during the accept processing.
1365 *
1366 * The acceptor stream accesses the eager in the accept processing
1367 * based on the ref placed on eager before sending T_conn_ind.
1368 * The only entity that can negate this refhold is a listener close
1369 * which is mutually exclusive with an active acceptor stream.
1370 *
1371 * Eager's reference on the listener
1372 * ===================================
1373 *
1374 * If the accept happens (even on a closed eager) the eager drops its
1375 * reference on the listener at the start of tcp_accept_finish. If the
1376 * eager is killed due to an incoming RST before the T_conn_ind is sent up,
1377 * the reference is dropped in tcp_closei_local. If the listener closes,
1378 * the reference is dropped in tcp_eager_kill. In all cases the reference
1379 * is dropped while executing in the eager's context (squeue).
1380 */
1381 /* END CSTYLED */
1382
1383 /* Process the SYN packet, mp, directed at the listener 'tcp' */
1384
1385 /*
1386 * THIS FUNCTION IS DIRECTLY CALLED BY IP VIA SQUEUE FOR SYN.
1387 * tcp_input_data will not see any packets for listeners since the listener
1388 * has conn_recv set to tcp_input_listener.
1389 */
1390 /* ARGSUSED */
1391 static void
1392 tcp_input_listener(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
1393 {
1394 tcpha_t *tcpha;
1395 uint32_t seg_seq;
1396 tcp_t *eager;
1397 int err;
1398 conn_t *econnp = NULL;
1399 squeue_t *new_sqp;
1400 mblk_t *mp1;
1401 uint_t ip_hdr_len;
1402 conn_t *lconnp = (conn_t *)arg;
1403 tcp_t *listener = lconnp->conn_tcp;
1404 tcp_stack_t *tcps = listener->tcp_tcps;
1405 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
1406 uint_t flags;
1407 mblk_t *tpi_mp;
1408 uint_t ifindex = ira->ira_ruifindex;
1409 boolean_t tlc_set = B_FALSE;
1410
1411 ip_hdr_len = ira->ira_ip_hdr_length;
1412 tcpha = (tcpha_t *)&mp->b_rptr[ip_hdr_len];
1413 flags = (unsigned int)tcpha->tha_flags & 0xFF;
1414
1415 DTRACE_TCP5(receive, mblk_t *, NULL, ip_xmit_attr_t *, lconnp->conn_ixa,
1416 __dtrace_tcp_void_ip_t *, mp->b_rptr, tcp_t *, listener,
1417 __dtrace_tcp_tcph_t *, tcpha);
1418
1419 if (!(flags & TH_SYN)) {
1420 if ((flags & TH_RST) || (flags & TH_URG)) {
1421 freemsg(mp);
1422 return;
1423 }
1424 if (flags & TH_ACK) {
1425 /* Note this executes in listener's squeue */
1426 tcp_xmit_listeners_reset(mp, ira, ipst, lconnp);
1427 return;
1428 }
1429
1430 freemsg(mp);
1431 return;
1432 }
1433
1434 if (listener->tcp_state != TCPS_LISTEN)
1435 goto error2;
1436
1437 ASSERT(IPCL_IS_BOUND(lconnp));
1438
1439 mutex_enter(&listener->tcp_eager_lock);
1440
1441 /*
1442 * The system is under memory pressure, so we need to do our part
1443 * to relieve the pressure. So we only accept new request if there
1444 * is nothing waiting to be accepted or waiting to complete the 3-way
1445 * handshake. This means that busy listener will not get too many
1446 * new requests which they cannot handle in time while non-busy
1447 * listener is still functioning properly.
1448 */
1449 if (tcps->tcps_reclaim && (listener->tcp_conn_req_cnt_q > 0 ||
1450 listener->tcp_conn_req_cnt_q0 > 0)) {
1451 mutex_exit(&listener->tcp_eager_lock);
1452 TCP_STAT(tcps, tcp_listen_mem_drop);
1453 goto error2;
1454 }
1455
1456 if (listener->tcp_conn_req_cnt_q >= listener->tcp_conn_req_max) {
1457 mutex_exit(&listener->tcp_eager_lock);
1458 TCP_STAT(tcps, tcp_listendrop);
1459 TCPS_BUMP_MIB(tcps, tcpListenDrop);
1460 if (lconnp->conn_debug) {
1461 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE|SL_ERROR,
1462 "tcp_input_listener: listen backlog (max=%d) "
1463 "overflow (%d pending) on %s",
1464 listener->tcp_conn_req_max,
1465 listener->tcp_conn_req_cnt_q,
1466 tcp_display(listener, NULL, DISP_PORT_ONLY));
1467 }
1468 goto error2;
1469 }
1470
1471 if (listener->tcp_conn_req_cnt_q0 >=
1472 listener->tcp_conn_req_max + tcps->tcps_conn_req_max_q0) {
1473 /*
1474 * Q0 is full. Drop a pending half-open req from the queue
1475 * to make room for the new SYN req. Also mark the time we
1476 * drop a SYN.
1477 *
1478 * A more aggressive defense against SYN attack will
1479 * be to set the "tcp_syn_defense" flag now.
1480 */
1481 TCP_STAT(tcps, tcp_listendropq0);
1482 listener->tcp_last_rcv_lbolt = ddi_get_lbolt64();
1483 if (!tcp_drop_q0(listener)) {
1484 mutex_exit(&listener->tcp_eager_lock);
1485 TCPS_BUMP_MIB(tcps, tcpListenDropQ0);
1486 if (lconnp->conn_debug) {
1487 (void) strlog(TCP_MOD_ID, 0, 3, SL_TRACE,
1488 "tcp_input_listener: listen half-open "
1489 "queue (max=%d) full (%d pending) on %s",
1490 tcps->tcps_conn_req_max_q0,
1491 listener->tcp_conn_req_cnt_q0,
1492 tcp_display(listener, NULL,
1493 DISP_PORT_ONLY));
1494 }
1495 goto error2;
1496 }
1497 }
1498
1499 /*
1500 * Enforce the limit set on the number of connections per listener.
1501 * Note that tlc_cnt starts with 1. So need to add 1 to tlc_max
1502 * for comparison.
1503 */
1504 if (listener->tcp_listen_cnt != NULL) {
1505 tcp_listen_cnt_t *tlc = listener->tcp_listen_cnt;
1506 int64_t now;
1507
1508 if (atomic_inc_32_nv(&tlc->tlc_cnt) > tlc->tlc_max + 1) {
1509 mutex_exit(&listener->tcp_eager_lock);
1510 now = ddi_get_lbolt64();
1511 atomic_dec_32(&tlc->tlc_cnt);
1512 TCP_STAT(tcps, tcp_listen_cnt_drop);
1513 tlc->tlc_drop++;
1514 if (now - tlc->tlc_report_time >
1515 MSEC_TO_TICK(TCP_TLC_REPORT_INTERVAL)) {
1516 zcmn_err(lconnp->conn_zoneid, CE_WARN,
1517 "Listener (port %d) connection max (%u) "
1518 "reached: %u attempts dropped total\n",
1519 ntohs(listener->tcp_connp->conn_lport),
1520 tlc->tlc_max, tlc->tlc_drop);
1521 tlc->tlc_report_time = now;
1522 }
1523 goto error2;
1524 }
1525 tlc_set = B_TRUE;
1526 }
1527
1528 mutex_exit(&listener->tcp_eager_lock);
1529
1530 /*
1531 * IP sets ira_sqp to either the senders conn_sqp (for loopback)
1532 * or based on the ring (for packets from GLD). Otherwise it is
1533 * set based on lbolt i.e., a somewhat random number.
1534 */
1535 ASSERT(ira->ira_sqp != NULL);
1536 new_sqp = ira->ira_sqp;
1537
1538 econnp = tcp_get_conn(arg2, tcps);
1539 if (econnp == NULL)
1540 goto error2;
1541
1542 ASSERT(econnp->conn_netstack == lconnp->conn_netstack);
1543 econnp->conn_sqp = new_sqp;
1544 econnp->conn_initial_sqp = new_sqp;
1545 econnp->conn_ixa->ixa_sqp = new_sqp;
1546
1547 econnp->conn_fport = tcpha->tha_lport;
1548 econnp->conn_lport = tcpha->tha_fport;
1549
1550 err = conn_inherit_parent(lconnp, econnp);
1551 if (err != 0)
1552 goto error3;
1553
1554 /* We already know the laddr of the new connection is ours */
1555 econnp->conn_ixa->ixa_src_generation = ipst->ips_src_generation;
1556
1557 ASSERT(OK_32PTR(mp->b_rptr));
1558 ASSERT(IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION ||
1559 IPH_HDR_VERSION(mp->b_rptr) == IPV6_VERSION);
1560
1561 if (lconnp->conn_family == AF_INET) {
1562 ASSERT(IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION);
1563 tpi_mp = tcp_conn_create_v4(lconnp, econnp, mp, ira);
1564 } else {
1565 tpi_mp = tcp_conn_create_v6(lconnp, econnp, mp, ira);
1566 }
1567
1568 if (tpi_mp == NULL)
1569 goto error3;
1570
1571 eager = econnp->conn_tcp;
1572 eager->tcp_detached = B_TRUE;
1573 SOCK_CONNID_INIT(eager->tcp_connid);
1574
1575 /*
1576 * Initialize the eager's tcp_t and inherit some parameters from
1577 * the listener.
1578 */
1579 tcp_init_values(eager, listener);
1580
1581 ASSERT((econnp->conn_ixa->ixa_flags &
1582 (IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE |
1583 IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO)) ==
1584 (IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE |
1585 IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO));
1586
1587 if (!tcps->tcps_dev_flow_ctl)
1588 econnp->conn_ixa->ixa_flags |= IXAF_NO_DEV_FLOW_CTL;
1589
1590 /* Prepare for diffing against previous packets */
1591 eager->tcp_recvifindex = 0;
1592 eager->tcp_recvhops = 0xffffffffU;
1593
1594 if (!(ira->ira_flags & IRAF_IS_IPV4) && econnp->conn_bound_if == 0) {
1595 if (IN6_IS_ADDR_LINKSCOPE(&econnp->conn_faddr_v6) ||
1596 IN6_IS_ADDR_LINKSCOPE(&econnp->conn_laddr_v6)) {
1597 econnp->conn_incoming_ifindex = ifindex;
1598 econnp->conn_ixa->ixa_flags |= IXAF_SCOPEID_SET;
1599 econnp->conn_ixa->ixa_scopeid = ifindex;
1600 }
1601 }
1602
1603 if ((ira->ira_flags & (IRAF_IS_IPV4|IRAF_IPV4_OPTIONS)) ==
1604 (IRAF_IS_IPV4|IRAF_IPV4_OPTIONS) &&
1605 tcps->tcps_rev_src_routes) {
1606 ipha_t *ipha = (ipha_t *)mp->b_rptr;
1607 ip_pkt_t *ipp = &econnp->conn_xmit_ipp;
1608
1609 /* Source routing option copyover (reverse it) */
1610 err = ip_find_hdr_v4(ipha, ipp, B_TRUE);
1611 if (err != 0) {
1612 freemsg(tpi_mp);
1613 goto error3;
1614 }
1615 ip_pkt_source_route_reverse_v4(ipp);
1616 }
1617
1618 ASSERT(eager->tcp_conn.tcp_eager_conn_ind == NULL);
1619 ASSERT(!eager->tcp_tconnind_started);
1620 /*
1621 * If the SYN came with a credential, it's a loopback packet or a
1622 * labeled packet; attach the credential to the TPI message.
1623 */
1624 if (ira->ira_cred != NULL)
1625 mblk_setcred(tpi_mp, ira->ira_cred, ira->ira_cpid);
1626
1627 eager->tcp_conn.tcp_eager_conn_ind = tpi_mp;
1628 ASSERT(eager->tcp_ordrel_mp == NULL);
1629
1630 /* Inherit the listener's non-STREAMS flag */
1631 if (IPCL_IS_NONSTR(lconnp)) {
1632 econnp->conn_flags |= IPCL_NONSTR;
1633 /* All non-STREAMS tcp_ts are sockets */
1634 eager->tcp_issocket = B_TRUE;
1635 } else {
1636 /*
1637 * Pre-allocate the T_ordrel_ind mblk for TPI socket so that
1638 * at close time, we will always have that to send up.
1639 * Otherwise, we need to do special handling in case the
1640 * allocation fails at that time.
1641 */
1642 if ((eager->tcp_ordrel_mp = mi_tpi_ordrel_ind()) == NULL)
1643 goto error3;
1644 }
1645 /*
1646 * Now that the IP addresses and ports are setup in econnp we
1647 * can do the IPsec policy work.
1648 */
1649 if (ira->ira_flags & IRAF_IPSEC_SECURE) {
1650 if (lconnp->conn_policy != NULL) {
1651 /*
1652 * Inherit the policy from the listener; use
1653 * actions from ira
1654 */
1655 if (!ip_ipsec_policy_inherit(econnp, lconnp, ira)) {
1656 CONN_DEC_REF(econnp);
1657 freemsg(mp);
1658 goto error3;
1659 }
1660 }
1661 }
1662
1663 /*
1664 * tcp_set_destination() may set tcp_rwnd according to the route
1665 * metrics. If it does not, the eager's receive window will be set
1666 * to the listener's receive window later in this function.
1667 */
1668 eager->tcp_rwnd = 0;
1669
1670 if (is_system_labeled()) {
1671 ip_xmit_attr_t *ixa = econnp->conn_ixa;
1672
1673 ASSERT(ira->ira_tsl != NULL);
1674 /* Discard any old label */
1675 if (ixa->ixa_free_flags & IXA_FREE_TSL) {
1676 ASSERT(ixa->ixa_tsl != NULL);
1677 label_rele(ixa->ixa_tsl);
1678 ixa->ixa_free_flags &= ~IXA_FREE_TSL;
1679 ixa->ixa_tsl = NULL;
1680 }
1681 if ((lconnp->conn_mlp_type != mlptSingle ||
1682 lconnp->conn_mac_mode != CONN_MAC_DEFAULT) &&
1683 ira->ira_tsl != NULL) {
1684 /*
1685 * If this is an MLP connection or a MAC-Exempt
1686 * connection with an unlabeled node, packets are to be
1687 * exchanged using the security label of the received
1688 * SYN packet instead of the server application's label.
1689 * tsol_check_dest called from ip_set_destination
1690 * might later update TSF_UNLABELED by replacing
1691 * ixa_tsl with a new label.
1692 */
1693 label_hold(ira->ira_tsl);
1694 ip_xmit_attr_replace_tsl(ixa, ira->ira_tsl);
1695 DTRACE_PROBE2(mlp_syn_accept, conn_t *,
1696 econnp, ts_label_t *, ixa->ixa_tsl)
1697 } else {
1698 ixa->ixa_tsl = crgetlabel(econnp->conn_cred);
1699 DTRACE_PROBE2(syn_accept, conn_t *,
1700 econnp, ts_label_t *, ixa->ixa_tsl)
1701 }
1702 /*
1703 * conn_connect() called from tcp_set_destination will verify
1704 * the destination is allowed to receive packets at the
1705 * security label of the SYN-ACK we are generating. As part of
1706 * that, tsol_check_dest() may create a new effective label for
1707 * this connection.
1708 * Finally conn_connect() will call conn_update_label.
1709 * All that remains for TCP to do is to call
1710 * conn_build_hdr_template which is done as part of
1711 * tcp_set_destination.
1712 */
1713 }
1714
1715 /*
1716 * Since we will clear tcp_listener before we clear tcp_detached
1717 * in the accept code we need tcp_hard_binding aka tcp_accept_inprogress
1718 * so we can tell a TCP_IS_DETACHED_NONEAGER apart.
1719 */
1720 eager->tcp_hard_binding = B_TRUE;
1721
1722 tcp_bind_hash_insert(&tcps->tcps_bind_fanout[
1723 TCP_BIND_HASH(econnp->conn_lport)], eager, 0);
1724
1725 CL_INET_CONNECT(econnp, B_FALSE, err);
1726 if (err != 0) {
1727 tcp_bind_hash_remove(eager);
1728 goto error3;
1729 }
1730
1731 SOCK_CONNID_BUMP(eager->tcp_connid);
1732
1733 /*
1734 * Adapt our mss, ttl, ... based on the remote address.
1735 */
1736
1737 if (tcp_set_destination(eager) != 0) {
1738 TCPS_BUMP_MIB(tcps, tcpAttemptFails);
1739 /* Undo the bind_hash_insert */
1740 tcp_bind_hash_remove(eager);
1741 goto error3;
1742 }
1743
1744 /* Process all TCP options. */
1745 tcp_process_options(eager, tcpha);
1746
1747 /* Is the other end ECN capable? */
1748 if (tcps->tcps_ecn_permitted >= 1 &&
1749 (tcpha->tha_flags & (TH_ECE|TH_CWR)) == (TH_ECE|TH_CWR)) {
1750 eager->tcp_ecn_ok = B_TRUE;
1751 }
1752
1753 /*
1754 * The listener's conn_rcvbuf should be the default window size or a
1755 * window size changed via SO_RCVBUF option. First round up the
1756 * eager's tcp_rwnd to the nearest MSS. Then find out the window
1757 * scale option value if needed. Call tcp_rwnd_set() to finish the
1758 * setting.
1759 *
1760 * Note if there is a rpipe metric associated with the remote host,
1761 * we should not inherit receive window size from listener.
1762 */
1763 eager->tcp_rwnd = MSS_ROUNDUP(
1764 (eager->tcp_rwnd == 0 ? econnp->conn_rcvbuf :
1765 eager->tcp_rwnd), eager->tcp_mss);
1766 if (eager->tcp_snd_ws_ok)
1767 tcp_set_ws_value(eager);
1768 /*
1769 * Note that this is the only place tcp_rwnd_set() is called for
1770 * accepting a connection. We need to call it here instead of
1771 * after the 3-way handshake because we need to tell the other
1772 * side our rwnd in the SYN-ACK segment.
1773 */
1774 (void) tcp_rwnd_set(eager, eager->tcp_rwnd);
1775
1776 ASSERT(eager->tcp_connp->conn_rcvbuf != 0 &&
1777 eager->tcp_connp->conn_rcvbuf == eager->tcp_rwnd);
1778
1779 ASSERT(econnp->conn_rcvbuf != 0 &&
1780 econnp->conn_rcvbuf == eager->tcp_rwnd);
1781
1782 /* Put a ref on the listener for the eager. */
1783 CONN_INC_REF(lconnp);
1784 mutex_enter(&listener->tcp_eager_lock);
1785 listener->tcp_eager_next_q0->tcp_eager_prev_q0 = eager;
1786 eager->tcp_eager_next_q0 = listener->tcp_eager_next_q0;
1787 listener->tcp_eager_next_q0 = eager;
1788 eager->tcp_eager_prev_q0 = listener;
1789
1790 /* Set tcp_listener before adding it to tcp_conn_fanout */
1791 eager->tcp_listener = listener;
1792 eager->tcp_saved_listener = listener;
1793
1794 /*
1795 * Set tcp_listen_cnt so that when the connection is done, the counter
1796 * is decremented.
1797 */
1798 eager->tcp_listen_cnt = listener->tcp_listen_cnt;
1799
1800 /*
1801 * Tag this detached tcp vector for later retrieval
1802 * by our listener client in tcp_accept().
1803 */
1804 eager->tcp_conn_req_seqnum = listener->tcp_conn_req_seqnum;
1805 listener->tcp_conn_req_cnt_q0++;
1806 if (++listener->tcp_conn_req_seqnum == -1) {
1807 /*
1808 * -1 is "special" and defined in TPI as something
1809 * that should never be used in T_CONN_IND
1810 */
1811 ++listener->tcp_conn_req_seqnum;
1812 }
1813 mutex_exit(&listener->tcp_eager_lock);
1814
1815 if (listener->tcp_syn_defense) {
1816 /* Don't drop the SYN that comes from a good IP source */
1817 ipaddr_t *addr_cache;
1818
1819 addr_cache = (ipaddr_t *)(listener->tcp_ip_addr_cache);
1820 if (addr_cache != NULL && econnp->conn_faddr_v4 ==
1821 addr_cache[IP_ADDR_CACHE_HASH(econnp->conn_faddr_v4)]) {
1822 eager->tcp_dontdrop = B_TRUE;
1823 }
1824 }
1825
1826 /*
1827 * We need to insert the eager in its own perimeter but as soon
1828 * as we do that, we expose the eager to the classifier and
1829 * should not touch any field outside the eager's perimeter.
1830 * So do all the work necessary before inserting the eager
1831 * in its own perimeter. Be optimistic that conn_connect()
1832 * will succeed but undo everything if it fails.
1833 */
1834 seg_seq = ntohl(tcpha->tha_seq);
1835 eager->tcp_irs = seg_seq;
1836 eager->tcp_rack = seg_seq;
1837 eager->tcp_rnxt = seg_seq + 1;
1838 eager->tcp_tcpha->tha_ack = htonl(eager->tcp_rnxt);
1839 TCPS_BUMP_MIB(tcps, tcpPassiveOpens);
1840 eager->tcp_state = TCPS_SYN_RCVD;
1841 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
1842 econnp->conn_ixa, void, NULL, tcp_t *, eager, void, NULL,
1843 int32_t, TCPS_LISTEN);
1844
1845 mp1 = tcp_xmit_mp(eager, eager->tcp_xmit_head, eager->tcp_mss,
1846 NULL, NULL, eager->tcp_iss, B_FALSE, NULL, B_FALSE);
1847 if (mp1 == NULL) {
1848 /*
1849 * Increment the ref count as we are going to
1850 * enqueueing an mp in squeue
1851 */
1852 CONN_INC_REF(econnp);
1853 goto error;
1854 }
1855
1856 /*
1857 * We need to start the rto timer. In normal case, we start
1858 * the timer after sending the packet on the wire (or at
1859 * least believing that packet was sent by waiting for
1860 * conn_ip_output() to return). Since this is the first packet
1861 * being sent on the wire for the eager, our initial tcp_rto
1862 * is at least tcp_rexmit_interval_min which is a fairly
1863 * large value to allow the algorithm to adjust slowly to large
1864 * fluctuations of RTT during first few transmissions.
1865 *
1866 * Starting the timer first and then sending the packet in this
1867 * case shouldn't make much difference since tcp_rexmit_interval_min
1868 * is of the order of several 100ms and starting the timer
1869 * first and then sending the packet will result in difference
1870 * of few micro seconds.
1871 *
1872 * Without this optimization, we are forced to hold the fanout
1873 * lock across the ipcl_bind_insert() and sending the packet
1874 * so that we don't race against an incoming packet (maybe RST)
1875 * for this eager.
1876 *
1877 * It is necessary to acquire an extra reference on the eager
1878 * at this point and hold it until after tcp_send_data() to
1879 * ensure against an eager close race.
1880 */
1881
1882 CONN_INC_REF(econnp);
1883
1884 TCP_TIMER_RESTART(eager, eager->tcp_rto);
1885
1886 /*
1887 * Insert the eager in its own perimeter now. We are ready to deal
1888 * with any packets on eager.
1889 */
1890 if (ipcl_conn_insert(econnp) != 0)
1891 goto error;
1892
1893 ASSERT(econnp->conn_ixa->ixa_notify_cookie == econnp->conn_tcp);
1894 freemsg(mp);
1895 /*
1896 * Send the SYN-ACK. Use the right squeue so that conn_ixa is
1897 * only used by one thread at a time.
1898 */
1899 if (econnp->conn_sqp == lconnp->conn_sqp) {
1900 DTRACE_TCP5(send, mblk_t *, NULL, ip_xmit_attr_t *,
1901 econnp->conn_ixa, __dtrace_tcp_void_ip_t *, mp1->b_rptr,
1902 tcp_t *, eager, __dtrace_tcp_tcph_t *,
1903 &mp1->b_rptr[econnp->conn_ixa->ixa_ip_hdr_length]);
1904 (void) conn_ip_output(mp1, econnp->conn_ixa);
1905 CONN_DEC_REF(econnp);
1906 } else {
1907 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp1, tcp_send_synack,
1908 econnp, NULL, SQ_PROCESS, SQTAG_TCP_SEND_SYNACK);
1909 }
1910 return;
1911 error:
1912 freemsg(mp1);
1913 eager->tcp_closemp_used = B_TRUE;
1914 TCP_DEBUG_GETPCSTACK(eager->tcmp_stk, 15);
1915 mp1 = &eager->tcp_closemp;
1916 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp1, tcp_eager_kill,
1917 econnp, NULL, SQ_FILL, SQTAG_TCP_CONN_REQ_2);
1918
1919 /*
1920 * If a connection already exists, send the mp to that connections so
1921 * that it can be appropriately dealt with.
1922 */
1923 ipst = tcps->tcps_netstack->netstack_ip;
1924
1925 if ((econnp = ipcl_classify(mp, ira, ipst)) != NULL) {
1926 if (!IPCL_IS_CONNECTED(econnp)) {
1927 /*
1928 * Something bad happened. ipcl_conn_insert()
1929 * failed because a connection already existed
1930 * in connected hash but we can't find it
1931 * anymore (someone blew it away). Just
1932 * free this message and hopefully remote
1933 * will retransmit at which time the SYN can be
1934 * treated as a new connection or dealth with
1935 * a TH_RST if a connection already exists.
1936 */
1937 CONN_DEC_REF(econnp);
1938 freemsg(mp);
1939 } else {
1940 SQUEUE_ENTER_ONE(econnp->conn_sqp, mp, tcp_input_data,
1941 econnp, ira, SQ_FILL, SQTAG_TCP_CONN_REQ_1);
1942 }
1943 } else {
1944 /* Nobody wants this packet */
1945 freemsg(mp);
1946 }
1947 return;
1948 error3:
1949 CONN_DEC_REF(econnp);
1950 error2:
1951 freemsg(mp);
1952 if (tlc_set)
1953 atomic_dec_32(&listener->tcp_listen_cnt->tlc_cnt);
1954 }
1955
1956 /*
1957 * In an ideal case of vertical partition in NUMA architecture, its
1958 * beneficial to have the listener and all the incoming connections
1959 * tied to the same squeue. The other constraint is that incoming
1960 * connections should be tied to the squeue attached to interrupted
1961 * CPU for obvious locality reason so this leaves the listener to
1962 * be tied to the same squeue. Our only problem is that when listener
1963 * is binding, the CPU that will get interrupted by the NIC whose
1964 * IP address the listener is binding to is not even known. So
1965 * the code below allows us to change that binding at the time the
1966 * CPU is interrupted by virtue of incoming connection's squeue.
1967 *
1968 * This is usefull only in case of a listener bound to a specific IP
1969 * address. For other kind of listeners, they get bound the
1970 * very first time and there is no attempt to rebind them.
1971 */
1972 void
1973 tcp_input_listener_unbound(void *arg, mblk_t *mp, void *arg2,
1974 ip_recv_attr_t *ira)
1975 {
1976 conn_t *connp = (conn_t *)arg;
1977 squeue_t *sqp = (squeue_t *)arg2;
1978 squeue_t *new_sqp;
1979 uint32_t conn_flags;
1980
1981 /*
1982 * IP sets ira_sqp to either the senders conn_sqp (for loopback)
1983 * or based on the ring (for packets from GLD). Otherwise it is
1984 * set based on lbolt i.e., a somewhat random number.
1985 */
1986 ASSERT(ira->ira_sqp != NULL);
1987 new_sqp = ira->ira_sqp;
1988
1989 if (connp->conn_fanout == NULL)
1990 goto done;
1991
1992 if (!(connp->conn_flags & IPCL_FULLY_BOUND)) {
1993 mutex_enter(&connp->conn_fanout->connf_lock);
1994 mutex_enter(&connp->conn_lock);
1995 /*
1996 * No one from read or write side can access us now
1997 * except for already queued packets on this squeue.
1998 * But since we haven't changed the squeue yet, they
1999 * can't execute. If they are processed after we have
2000 * changed the squeue, they are sent back to the
2001 * correct squeue down below.
2002 * But a listner close can race with processing of
2003 * incoming SYN. If incoming SYN processing changes
2004 * the squeue then the listener close which is waiting
2005 * to enter the squeue would operate on the wrong
2006 * squeue. Hence we don't change the squeue here unless
2007 * the refcount is exactly the minimum refcount. The
2008 * minimum refcount of 4 is counted as - 1 each for
2009 * TCP and IP, 1 for being in the classifier hash, and
2010 * 1 for the mblk being processed.
2011 */
2012
2013 if (connp->conn_ref != 4 ||
2014 connp->conn_tcp->tcp_state != TCPS_LISTEN) {
2015 mutex_exit(&connp->conn_lock);
2016 mutex_exit(&connp->conn_fanout->connf_lock);
2017 goto done;
2018 }
2019 if (connp->conn_sqp != new_sqp) {
2020 while (connp->conn_sqp != new_sqp)
2021 (void) atomic_cas_ptr(&connp->conn_sqp, sqp,
2022 new_sqp);
2023 /* No special MT issues for outbound ixa_sqp hint */
2024 connp->conn_ixa->ixa_sqp = new_sqp;
2025 }
2026
2027 do {
2028 conn_flags = connp->conn_flags;
2029 conn_flags |= IPCL_FULLY_BOUND;
2030 (void) atomic_cas_32(&connp->conn_flags,
2031 connp->conn_flags, conn_flags);
2032 } while (!(connp->conn_flags & IPCL_FULLY_BOUND));
2033
2034 mutex_exit(&connp->conn_fanout->connf_lock);
2035 mutex_exit(&connp->conn_lock);
2036
2037 /*
2038 * Assume we have picked a good squeue for the listener. Make
2039 * subsequent SYNs not try to change the squeue.
2040 */
2041 connp->conn_recv = tcp_input_listener;
2042 }
2043
2044 done:
2045 if (connp->conn_sqp != sqp) {
2046 CONN_INC_REF(connp);
2047 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, connp->conn_recv, connp,
2048 ira, SQ_FILL, SQTAG_TCP_CONN_REQ_UNBOUND);
2049 } else {
2050 tcp_input_listener(connp, mp, sqp, ira);
2051 }
2052 }
2053
2054 /*
2055 * Send up all messages queued on tcp_rcv_list.
2056 */
2057 uint_t
2058 tcp_rcv_drain(tcp_t *tcp)
2059 {
2060 mblk_t *mp;
2061 uint_t ret = 0;
2062 #ifdef DEBUG
2063 uint_t cnt = 0;
2064 #endif
2065 queue_t *q = tcp->tcp_connp->conn_rq;
2066
2067 /* Can't drain on an eager connection */
2068 if (tcp->tcp_listener != NULL)
2069 return (ret);
2070
2071 /* Can't be a non-STREAMS connection */
2072 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
2073
2074 /* No need for the push timer now. */
2075 if (tcp->tcp_push_tid != 0) {
2076 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
2077 tcp->tcp_push_tid = 0;
2078 }
2079
2080 /*
2081 * Handle two cases here: we are currently fused or we were
2082 * previously fused and have some urgent data to be delivered
2083 * upstream. The latter happens because we either ran out of
2084 * memory or were detached and therefore sending the SIGURG was
2085 * deferred until this point. In either case we pass control
2086 * over to tcp_fuse_rcv_drain() since it may need to complete
2087 * some work.
2088 */
2089 if ((tcp->tcp_fused || tcp->tcp_fused_sigurg)) {
2090 if (tcp_fuse_rcv_drain(q, tcp, tcp->tcp_fused ? NULL :
2091 &tcp->tcp_fused_sigurg_mp))
2092 return (ret);
2093 }
2094
2095 while ((mp = tcp->tcp_rcv_list) != NULL) {
2096 tcp->tcp_rcv_list = mp->b_next;
2097 mp->b_next = NULL;
2098 #ifdef DEBUG
2099 cnt += msgdsize(mp);
2100 #endif
2101 putnext(q, mp);
2102 }
2103 #ifdef DEBUG
2104 ASSERT(cnt == tcp->tcp_rcv_cnt);
2105 #endif
2106 tcp->tcp_rcv_last_head = NULL;
2107 tcp->tcp_rcv_last_tail = NULL;
2108 tcp->tcp_rcv_cnt = 0;
2109
2110 if (canputnext(q))
2111 return (tcp_rwnd_reopen(tcp));
2112
2113 return (ret);
2114 }
2115
2116 /*
2117 * Queue data on tcp_rcv_list which is a b_next chain.
2118 * tcp_rcv_last_head/tail is the last element of this chain.
2119 * Each element of the chain is a b_cont chain.
2120 *
2121 * M_DATA messages are added to the current element.
2122 * Other messages are added as new (b_next) elements.
2123 */
2124 void
2125 tcp_rcv_enqueue(tcp_t *tcp, mblk_t *mp, uint_t seg_len, cred_t *cr)
2126 {
2127 ASSERT(seg_len == msgdsize(mp));
2128 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_rcv_last_head != NULL);
2129
2130 if (is_system_labeled()) {
2131 ASSERT(cr != NULL || msg_getcred(mp, NULL) != NULL);
2132 /*
2133 * Provide for protocols above TCP such as RPC. NOPID leaves
2134 * db_cpid unchanged.
2135 * The cred could have already been set.
2136 */
2137 if (cr != NULL)
2138 mblk_setcred(mp, cr, NOPID);
2139 }
2140
2141 if (tcp->tcp_rcv_list == NULL) {
2142 ASSERT(tcp->tcp_rcv_last_head == NULL);
2143 tcp->tcp_rcv_list = mp;
2144 tcp->tcp_rcv_last_head = mp;
2145 } else if (DB_TYPE(mp) == DB_TYPE(tcp->tcp_rcv_last_head)) {
2146 tcp->tcp_rcv_last_tail->b_cont = mp;
2147 } else {
2148 tcp->tcp_rcv_last_head->b_next = mp;
2149 tcp->tcp_rcv_last_head = mp;
2150 }
2151
2152 while (mp->b_cont)
2153 mp = mp->b_cont;
2154
2155 tcp->tcp_rcv_last_tail = mp;
2156 tcp->tcp_rcv_cnt += seg_len;
2157 tcp->tcp_rwnd -= seg_len;
2158 }
2159
2160 /* Generate an ACK-only (no data) segment for a TCP endpoint */
2161 mblk_t *
2162 tcp_ack_mp(tcp_t *tcp)
2163 {
2164 uint32_t seq_no;
2165 tcp_stack_t *tcps = tcp->tcp_tcps;
2166 conn_t *connp = tcp->tcp_connp;
2167
2168 /*
2169 * There are a few cases to be considered while setting the sequence no.
2170 * Essentially, we can come here while processing an unacceptable pkt
2171 * in the TCPS_SYN_RCVD state, in which case we set the sequence number
2172 * to snxt (per RFC 793), note the swnd wouldn't have been set yet.
2173 * If we are here for a zero window probe, stick with suna. In all
2174 * other cases, we check if suna + swnd encompasses snxt and set
2175 * the sequence number to snxt, if so. If snxt falls outside the
2176 * window (the receiver probably shrunk its window), we will go with
2177 * suna + swnd, otherwise the sequence no will be unacceptable to the
2178 * receiver.
2179 */
2180 if (tcp->tcp_zero_win_probe) {
2181 seq_no = tcp->tcp_suna;
2182 } else if (tcp->tcp_state == TCPS_SYN_RCVD) {
2183 ASSERT(tcp->tcp_swnd == 0);
2184 seq_no = tcp->tcp_snxt;
2185 } else {
2186 seq_no = SEQ_GT(tcp->tcp_snxt,
2187 (tcp->tcp_suna + tcp->tcp_swnd)) ?
2188 (tcp->tcp_suna + tcp->tcp_swnd) : tcp->tcp_snxt;
2189 }
2190
2191 if (tcp->tcp_valid_bits) {
2192 /*
2193 * For the complex case where we have to send some
2194 * controls (FIN or SYN), let tcp_xmit_mp do it.
2195 */
2196 return (tcp_xmit_mp(tcp, NULL, 0, NULL, NULL, seq_no, B_FALSE,
2197 NULL, B_FALSE));
2198 } else {
2199 /* Generate a simple ACK */
2200 int data_length;
2201 uchar_t *rptr;
2202 tcpha_t *tcpha;
2203 mblk_t *mp1;
2204 int32_t total_hdr_len;
2205 int32_t tcp_hdr_len;
2206 int32_t num_sack_blk = 0;
2207 int32_t sack_opt_len;
2208 ip_xmit_attr_t *ixa = connp->conn_ixa;
2209
2210 /*
2211 * Allocate space for TCP + IP headers
2212 * and link-level header
2213 */
2214 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
2215 num_sack_blk = MIN(tcp->tcp_max_sack_blk,
2216 tcp->tcp_num_sack_blk);
2217 sack_opt_len = num_sack_blk * sizeof (sack_blk_t) +
2218 TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN;
2219 total_hdr_len = connp->conn_ht_iphc_len + sack_opt_len;
2220 tcp_hdr_len = connp->conn_ht_ulp_len + sack_opt_len;
2221 } else {
2222 total_hdr_len = connp->conn_ht_iphc_len;
2223 tcp_hdr_len = connp->conn_ht_ulp_len;
2224 }
2225 mp1 = allocb(total_hdr_len + tcps->tcps_wroff_xtra, BPRI_MED);
2226 if (!mp1)
2227 return (NULL);
2228
2229 /* Update the latest receive window size in TCP header. */
2230 tcp->tcp_tcpha->tha_win =
2231 htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
2232 /* copy in prototype TCP + IP header */
2233 rptr = mp1->b_rptr + tcps->tcps_wroff_xtra;
2234 mp1->b_rptr = rptr;
2235 mp1->b_wptr = rptr + total_hdr_len;
2236 bcopy(connp->conn_ht_iphc, rptr, connp->conn_ht_iphc_len);
2237
2238 tcpha = (tcpha_t *)&rptr[ixa->ixa_ip_hdr_length];
2239
2240 /* Set the TCP sequence number. */
2241 tcpha->tha_seq = htonl(seq_no);
2242
2243 /* Set up the TCP flag field. */
2244 tcpha->tha_flags = (uchar_t)TH_ACK;
2245 if (tcp->tcp_ecn_echo_on)
2246 tcpha->tha_flags |= TH_ECE;
2247
2248 tcp->tcp_rack = tcp->tcp_rnxt;
2249 tcp->tcp_rack_cnt = 0;
2250
2251 /* fill in timestamp option if in use */
2252 if (tcp->tcp_snd_ts_ok) {
2253 uint32_t llbolt = (uint32_t)LBOLT_FASTPATH;
2254
2255 U32_TO_BE32(llbolt,
2256 (char *)tcpha + TCP_MIN_HEADER_LENGTH+4);
2257 U32_TO_BE32(tcp->tcp_ts_recent,
2258 (char *)tcpha + TCP_MIN_HEADER_LENGTH+8);
2259 }
2260
2261 /* Fill in SACK options */
2262 if (num_sack_blk > 0) {
2263 uchar_t *wptr = (uchar_t *)tcpha +
2264 connp->conn_ht_ulp_len;
2265 sack_blk_t *tmp;
2266 int32_t i;
2267
2268 wptr[0] = TCPOPT_NOP;
2269 wptr[1] = TCPOPT_NOP;
2270 wptr[2] = TCPOPT_SACK;
2271 wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk *
2272 sizeof (sack_blk_t);
2273 wptr += TCPOPT_REAL_SACK_LEN;
2274
2275 tmp = tcp->tcp_sack_list;
2276 for (i = 0; i < num_sack_blk; i++) {
2277 U32_TO_BE32(tmp[i].begin, wptr);
2278 wptr += sizeof (tcp_seq);
2279 U32_TO_BE32(tmp[i].end, wptr);
2280 wptr += sizeof (tcp_seq);
2281 }
2282 tcpha->tha_offset_and_reserved +=
2283 ((num_sack_blk * 2 + 1) << 4);
2284 }
2285
2286 ixa->ixa_pktlen = total_hdr_len;
2287
2288 if (ixa->ixa_flags & IXAF_IS_IPV4) {
2289 ((ipha_t *)rptr)->ipha_length = htons(total_hdr_len);
2290 } else {
2291 ip6_t *ip6 = (ip6_t *)rptr;
2292
2293 ip6->ip6_plen = htons(total_hdr_len - IPV6_HDR_LEN);
2294 }
2295
2296 /*
2297 * Prime pump for checksum calculation in IP. Include the
2298 * adjustment for a source route if any.
2299 */
2300 data_length = tcp_hdr_len + connp->conn_sum;
2301 data_length = (data_length >> 16) + (data_length & 0xFFFF);
2302 tcpha->tha_sum = htons(data_length);
2303
2304 if (tcp->tcp_ip_forward_progress) {
2305 tcp->tcp_ip_forward_progress = B_FALSE;
2306 connp->conn_ixa->ixa_flags |= IXAF_REACH_CONF;
2307 } else {
2308 connp->conn_ixa->ixa_flags &= ~IXAF_REACH_CONF;
2309 }
2310 return (mp1);
2311 }
2312 }
2313
2314 /*
2315 * Dummy socket upcalls for if/when the conn_t gets detached from a
2316 * direct-callback sonode via a user-driven close(). Easy to catch with
2317 * DTrace FBT, and should be mostly harmless.
2318 */
2319
2320 /* ARGSUSED */
2321 static sock_upper_handle_t
2322 tcp_dummy_newconn(sock_upper_handle_t x, sock_lower_handle_t y,
2323 sock_downcalls_t *z, cred_t *cr, pid_t pid, sock_upcalls_t **ignored)
2324 {
2325 ASSERT(0); /* Panic in debug, otherwise ignore. */
2326 return (NULL);
2327 }
2328
2329 /* ARGSUSED */
2330 static void
2331 tcp_dummy_connected(sock_upper_handle_t x, sock_connid_t y, cred_t *cr,
2332 pid_t pid)
2333 {
2334 ASSERT(x == NULL);
2335 /* Normally we'd crhold(cr) and attach it to socket state. */
2336 /* LINTED */
2337 }
2338
2339 /* ARGSUSED */
2340 static int
2341 tcp_dummy_disconnected(sock_upper_handle_t x, sock_connid_t y, int blah)
2342 {
2343 ASSERT(0); /* Panic in debug, otherwise ignore. */
2344 return (-1);
2345 }
2346
2347 /* ARGSUSED */
2348 static void
2349 tcp_dummy_opctl(sock_upper_handle_t x, sock_opctl_action_t y, uintptr_t blah)
2350 {
2351 ASSERT(x == NULL);
2352 /* We really want this one to be a harmless NOP for now. */
2353 /* LINTED */
2354 }
2355
2356 /* ARGSUSED */
2357 static ssize_t
2358 tcp_dummy_recv(sock_upper_handle_t x, mblk_t *mp, size_t len, int flags,
2359 int *error, boolean_t *push)
2360 {
2361 ASSERT(x == NULL);
2362
2363 /*
2364 * Consume the message, set ESHUTDOWN, and return an error.
2365 * Nobody's home!
2366 */
2367 freemsg(mp);
2368 *error = ESHUTDOWN;
2369 return (-1);
2370 }
2371
2372 /* ARGSUSED */
2373 static void
2374 tcp_dummy_set_proto_props(sock_upper_handle_t x, struct sock_proto_props *y)
2375 {
2376 ASSERT(0); /* Panic in debug, otherwise ignore. */
2377 }
2378
2379 /* ARGSUSED */
2380 static void
2381 tcp_dummy_txq_full(sock_upper_handle_t x, boolean_t y)
2382 {
2383 ASSERT(0); /* Panic in debug, otherwise ignore. */
2384 }
2385
2386 /* ARGSUSED */
2387 static void
2388 tcp_dummy_signal_oob(sock_upper_handle_t x, ssize_t len)
2389 {
2390 ASSERT(x == NULL);
2391 /* Otherwise, this would signal socket state about OOB data. */
2392 }
2393
2394 /* ARGSUSED */
2395 static void
2396 tcp_dummy_set_error(sock_upper_handle_t x, int err)
2397 {
2398 ASSERT(0); /* Panic in debug, otherwise ignore. */
2399 }
2400
2401 /* ARGSUSED */
2402 static void
2403 tcp_dummy_onearg(sock_upper_handle_t x)
2404 {
2405 ASSERT(0); /* Panic in debug, otherwise ignore. */
2406 }
2407
2408 static sock_upcalls_t tcp_dummy_upcalls = {
2409 tcp_dummy_newconn,
2410 tcp_dummy_connected,
2411 tcp_dummy_disconnected,
2412 tcp_dummy_opctl,
2413 tcp_dummy_recv,
2414 tcp_dummy_set_proto_props,
2415 tcp_dummy_txq_full,
2416 tcp_dummy_signal_oob,
2417 tcp_dummy_onearg,
2418 tcp_dummy_set_error,
2419 tcp_dummy_onearg
2420 };
2421
2422 /*
2423 * Handle M_DATA messages from IP. Its called directly from IP via
2424 * squeue for received IP packets.
2425 *
2426 * The first argument is always the connp/tcp to which the mp belongs.
2427 * There are no exceptions to this rule. The caller has already put
2428 * a reference on this connp/tcp and once tcp_input_data() returns,
2429 * the squeue will do the refrele.
2430 *
2431 * The TH_SYN for the listener directly go to tcp_input_listener via
2432 * squeue. ICMP errors go directly to tcp_icmp_input().
2433 *
2434 * sqp: NULL = recursive, sqp != NULL means called from squeue
2435 */
2436 void
2437 tcp_input_data(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
2438 {
2439 int32_t bytes_acked;
2440 int32_t gap;
2441 mblk_t *mp1;
2442 uint_t flags;
2443 uint32_t new_swnd = 0;
2444 uchar_t *iphdr;
2445 uchar_t *rptr;
2446 int32_t rgap;
2447 uint32_t seg_ack;
2448 int seg_len;
2449 uint_t ip_hdr_len;
2450 uint32_t seg_seq;
2451 tcpha_t *tcpha;
2452 int urp;
2453 tcp_opt_t tcpopt;
2454 ip_pkt_t ipp;
2455 boolean_t ofo_seg = B_FALSE; /* Out of order segment */
2456 uint32_t cwnd;
2457 int mss;
2458 conn_t *connp = (conn_t *)arg;
2459 squeue_t *sqp = (squeue_t *)arg2;
2460 tcp_t *tcp = connp->conn_tcp;
2461 tcp_stack_t *tcps = tcp->tcp_tcps;
2462 sock_upcalls_t *sockupcalls;
2463
2464 /*
2465 * RST from fused tcp loopback peer should trigger an unfuse.
2466 */
2467 if (tcp->tcp_fused) {
2468 TCP_STAT(tcps, tcp_fusion_aborted);
2469 tcp_unfuse(tcp);
2470 }
2471
2472 iphdr = mp->b_rptr;
2473 rptr = mp->b_rptr;
2474 ASSERT(OK_32PTR(rptr));
2475
2476 ip_hdr_len = ira->ira_ip_hdr_length;
2477 if (connp->conn_recv_ancillary.crb_all != 0) {
2478 /*
2479 * Record packet information in the ip_pkt_t
2480 */
2481 ipp.ipp_fields = 0;
2482 if (ira->ira_flags & IRAF_IS_IPV4) {
2483 (void) ip_find_hdr_v4((ipha_t *)rptr, &ipp,
2484 B_FALSE);
2485 } else {
2486 uint8_t nexthdrp;
2487
2488 /*
2489 * IPv6 packets can only be received by applications
2490 * that are prepared to receive IPv6 addresses.
2491 * The IP fanout must ensure this.
2492 */
2493 ASSERT(connp->conn_family == AF_INET6);
2494
2495 (void) ip_find_hdr_v6(mp, (ip6_t *)rptr, B_TRUE, &ipp,
2496 &nexthdrp);
2497 ASSERT(nexthdrp == IPPROTO_TCP);
2498
2499 /* Could have caused a pullup? */
2500 iphdr = mp->b_rptr;
2501 rptr = mp->b_rptr;
2502 }
2503 }
2504 ASSERT(DB_TYPE(mp) == M_DATA);
2505 ASSERT(mp->b_next == NULL);
2506
2507 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2508 seg_seq = ntohl(tcpha->tha_seq);
2509 seg_ack = ntohl(tcpha->tha_ack);
2510 ASSERT((uintptr_t)(mp->b_wptr - rptr) <= (uintptr_t)INT_MAX);
2511 seg_len = (int)(mp->b_wptr - rptr) -
2512 (ip_hdr_len + TCP_HDR_LENGTH(tcpha));
2513 if ((mp1 = mp->b_cont) != NULL && mp1->b_datap->db_type == M_DATA) {
2514 do {
2515 ASSERT((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <=
2516 (uintptr_t)INT_MAX);
2517 seg_len += (int)(mp1->b_wptr - mp1->b_rptr);
2518 } while ((mp1 = mp1->b_cont) != NULL &&
2519 mp1->b_datap->db_type == M_DATA);
2520 }
2521
2522 DTRACE_TCP5(receive, mblk_t *, NULL, ip_xmit_attr_t *, connp->conn_ixa,
2523 __dtrace_tcp_void_ip_t *, iphdr, tcp_t *, tcp,
2524 __dtrace_tcp_tcph_t *, tcpha);
2525
2526 if (tcp->tcp_state == TCPS_TIME_WAIT) {
2527 tcp_time_wait_processing(tcp, mp, seg_seq, seg_ack,
2528 seg_len, tcpha, ira);
2529 return;
2530 }
2531
2532 if (sqp != NULL) {
2533 /*
2534 * This is the correct place to update tcp_last_recv_time. Note
2535 * that it is also updated for tcp structure that belongs to
2536 * global and listener queues which do not really need updating.
2537 * But that should not cause any harm. And it is updated for
2538 * all kinds of incoming segments, not only for data segments.
2539 */
2540 tcp->tcp_last_recv_time = LBOLT_FASTPATH;
2541 }
2542
2543 flags = (unsigned int)tcpha->tha_flags & 0xFF;
2544
2545 TCPS_BUMP_MIB(tcps, tcpHCInSegs);
2546 DTRACE_PROBE2(tcp__trace__recv, mblk_t *, mp, tcp_t *, tcp);
2547
2548 if ((flags & TH_URG) && sqp != NULL) {
2549 /*
2550 * TCP can't handle urgent pointers that arrive before
2551 * the connection has been accept()ed since it can't
2552 * buffer OOB data. Discard segment if this happens.
2553 *
2554 * We can't just rely on a non-null tcp_listener to indicate
2555 * that the accept() has completed since unlinking of the
2556 * eager and completion of the accept are not atomic.
2557 * tcp_detached, when it is not set (B_FALSE) indicates
2558 * that the accept() has completed.
2559 *
2560 * Nor can it reassemble urgent pointers, so discard
2561 * if it's not the next segment expected.
2562 *
2563 * Otherwise, collapse chain into one mblk (discard if
2564 * that fails). This makes sure the headers, retransmitted
2565 * data, and new data all are in the same mblk.
2566 */
2567 ASSERT(mp != NULL);
2568 if (tcp->tcp_detached || !pullupmsg(mp, -1)) {
2569 freemsg(mp);
2570 return;
2571 }
2572 /* Update pointers into message */
2573 iphdr = rptr = mp->b_rptr;
2574 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2575 if (SEQ_GT(seg_seq, tcp->tcp_rnxt)) {
2576 /*
2577 * Since we can't handle any data with this urgent
2578 * pointer that is out of sequence, we expunge
2579 * the data. This allows us to still register
2580 * the urgent mark and generate the M_PCSIG,
2581 * which we can do.
2582 */
2583 mp->b_wptr = (uchar_t *)tcpha + TCP_HDR_LENGTH(tcpha);
2584 seg_len = 0;
2585 }
2586 }
2587
2588 sockupcalls = connp->conn_upcalls;
2589 /* A conn_t may have belonged to a now-closed socket. Be careful. */
2590 if (sockupcalls == NULL)
2591 sockupcalls = &tcp_dummy_upcalls;
2592
2593 switch (tcp->tcp_state) {
2594 case TCPS_SYN_SENT:
2595 if (connp->conn_final_sqp == NULL &&
2596 tcp_outbound_squeue_switch && sqp != NULL) {
2597 ASSERT(connp->conn_initial_sqp == connp->conn_sqp);
2598 connp->conn_final_sqp = sqp;
2599 if (connp->conn_final_sqp != connp->conn_sqp) {
2600 DTRACE_PROBE1(conn__final__sqp__switch,
2601 conn_t *, connp);
2602 CONN_INC_REF(connp);
2603 SQUEUE_SWITCH(connp, connp->conn_final_sqp);
2604 SQUEUE_ENTER_ONE(connp->conn_sqp, mp,
2605 tcp_input_data, connp, ira, ip_squeue_flag,
2606 SQTAG_CONNECT_FINISH);
2607 return;
2608 }
2609 DTRACE_PROBE1(conn__final__sqp__same, conn_t *, connp);
2610 }
2611 if (flags & TH_ACK) {
2612 /*
2613 * Note that our stack cannot send data before a
2614 * connection is established, therefore the
2615 * following check is valid. Otherwise, it has
2616 * to be changed.
2617 */
2618 if (SEQ_LEQ(seg_ack, tcp->tcp_iss) ||
2619 SEQ_GT(seg_ack, tcp->tcp_snxt)) {
2620 freemsg(mp);
2621 if (flags & TH_RST)
2622 return;
2623 tcp_xmit_ctl("TCPS_SYN_SENT-Bad_seq",
2624 tcp, seg_ack, 0, TH_RST);
2625 return;
2626 }
2627 ASSERT(tcp->tcp_suna + 1 == seg_ack);
2628 }
2629 if (flags & TH_RST) {
2630 if (flags & TH_ACK) {
2631 DTRACE_TCP5(connect__refused, mblk_t *, NULL,
2632 ip_xmit_attr_t *, connp->conn_ixa,
2633 void_ip_t *, iphdr, tcp_t *, tcp,
2634 tcph_t *, tcpha);
2635 (void) tcp_clean_death(tcp, ECONNREFUSED);
2636 }
2637 freemsg(mp);
2638 return;
2639 }
2640 if (!(flags & TH_SYN)) {
2641 freemsg(mp);
2642 return;
2643 }
2644
2645 /* Process all TCP options. */
2646 tcp_process_options(tcp, tcpha);
2647 /*
2648 * The following changes our rwnd to be a multiple of the
2649 * MIN(peer MSS, our MSS) for performance reason.
2650 */
2651 (void) tcp_rwnd_set(tcp, MSS_ROUNDUP(connp->conn_rcvbuf,
2652 tcp->tcp_mss));
2653
2654 /* Is the other end ECN capable? */
2655 if (tcp->tcp_ecn_ok) {
2656 if ((flags & (TH_ECE|TH_CWR)) != TH_ECE) {
2657 tcp->tcp_ecn_ok = B_FALSE;
2658 }
2659 }
2660 /*
2661 * Clear ECN flags because it may interfere with later
2662 * processing.
2663 */
2664 flags &= ~(TH_ECE|TH_CWR);
2665
2666 tcp->tcp_irs = seg_seq;
2667 tcp->tcp_rack = seg_seq;
2668 tcp->tcp_rnxt = seg_seq + 1;
2669 tcp->tcp_tcpha->tha_ack = htonl(tcp->tcp_rnxt);
2670 if (!TCP_IS_DETACHED(tcp)) {
2671 /* Allocate room for SACK options if needed. */
2672 connp->conn_wroff = connp->conn_ht_iphc_len;
2673 if (tcp->tcp_snd_sack_ok)
2674 connp->conn_wroff += TCPOPT_MAX_SACK_LEN;
2675 if (!tcp->tcp_loopback)
2676 connp->conn_wroff += tcps->tcps_wroff_xtra;
2677
2678 (void) proto_set_tx_wroff(connp->conn_rq, connp,
2679 connp->conn_wroff);
2680 }
2681 if (flags & TH_ACK) {
2682 /*
2683 * If we can't get the confirmation upstream, pretend
2684 * we didn't even see this one.
2685 *
2686 * XXX: how can we pretend we didn't see it if we
2687 * have updated rnxt et. al.
2688 *
2689 * For loopback we defer sending up the T_CONN_CON
2690 * until after some checks below.
2691 */
2692 mp1 = NULL;
2693 /*
2694 * tcp_sendmsg() checks tcp_state without entering
2695 * the squeue so tcp_state should be updated before
2696 * sending up connection confirmation. Probe the
2697 * state change below when we are sure the connection
2698 * confirmation has been sent.
2699 */
2700 tcp->tcp_state = TCPS_ESTABLISHED;
2701 if (!tcp_conn_con(tcp, iphdr, mp,
2702 tcp->tcp_loopback ? &mp1 : NULL, ira)) {
2703 tcp->tcp_state = TCPS_SYN_SENT;
2704 freemsg(mp);
2705 return;
2706 }
2707 TCPS_CONN_INC(tcps);
2708 /* SYN was acked - making progress */
2709 tcp->tcp_ip_forward_progress = B_TRUE;
2710
2711 /* One for the SYN */
2712 tcp->tcp_suna = tcp->tcp_iss + 1;
2713 tcp->tcp_valid_bits &= ~TCP_ISS_VALID;
2714
2715 /*
2716 * If SYN was retransmitted, need to reset all
2717 * retransmission info. This is because this
2718 * segment will be treated as a dup ACK.
2719 */
2720 if (tcp->tcp_rexmit) {
2721 tcp->tcp_rexmit = B_FALSE;
2722 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
2723 tcp->tcp_rexmit_max = tcp->tcp_snxt;
2724 tcp->tcp_ms_we_have_waited = 0;
2725
2726 /*
2727 * Set tcp_cwnd back to 1 MSS, per
2728 * recommendation from
2729 * draft-floyd-incr-init-win-01.txt,
2730 * Increasing TCP's Initial Window.
2731 */
2732 DTRACE_PROBE3(cwnd__retransmitted__syn,
2733 tcp_t *, tcp, uint32_t, tcp->tcp_cwnd,
2734 uint32_t, tcp->tcp_mss);
2735 tcp->tcp_cwnd = tcp->tcp_mss;
2736 }
2737
2738 tcp->tcp_swl1 = seg_seq;
2739 tcp->tcp_swl2 = seg_ack;
2740
2741 new_swnd = ntohs(tcpha->tha_win);
2742 tcp->tcp_swnd = new_swnd;
2743 if (new_swnd > tcp->tcp_max_swnd)
2744 tcp->tcp_max_swnd = new_swnd;
2745
2746 /*
2747 * Always send the three-way handshake ack immediately
2748 * in order to make the connection complete as soon as
2749 * possible on the accepting host.
2750 */
2751 flags |= TH_ACK_NEEDED;
2752
2753 /*
2754 * Trace connect-established here.
2755 */
2756 DTRACE_TCP5(connect__established, mblk_t *, NULL,
2757 ip_xmit_attr_t *, tcp->tcp_connp->conn_ixa,
2758 void_ip_t *, iphdr, tcp_t *, tcp, tcph_t *, tcpha);
2759
2760 /* Trace change from SYN_SENT -> ESTABLISHED here */
2761 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
2762 connp->conn_ixa, void, NULL, tcp_t *, tcp,
2763 void, NULL, int32_t, TCPS_SYN_SENT);
2764
2765 /*
2766 * Special case for loopback. At this point we have
2767 * received SYN-ACK from the remote endpoint. In
2768 * order to ensure that both endpoints reach the
2769 * fused state prior to any data exchange, the final
2770 * ACK needs to be sent before we indicate T_CONN_CON
2771 * to the module upstream.
2772 */
2773 if (tcp->tcp_loopback) {
2774 mblk_t *ack_mp;
2775
2776 ASSERT(!tcp->tcp_unfusable);
2777 ASSERT(mp1 != NULL);
2778 /*
2779 * For loopback, we always get a pure SYN-ACK
2780 * and only need to send back the final ACK
2781 * with no data (this is because the other
2782 * tcp is ours and we don't do T/TCP). This
2783 * final ACK triggers the passive side to
2784 * perform fusion in ESTABLISHED state.
2785 */
2786 if ((ack_mp = tcp_ack_mp(tcp)) != NULL) {
2787 if (tcp->tcp_ack_tid != 0) {
2788 (void) TCP_TIMER_CANCEL(tcp,
2789 tcp->tcp_ack_tid);
2790 tcp->tcp_ack_tid = 0;
2791 }
2792 tcp_send_data(tcp, ack_mp);
2793 TCPS_BUMP_MIB(tcps, tcpHCOutSegs);
2794 TCPS_BUMP_MIB(tcps, tcpOutAck);
2795
2796 if (!IPCL_IS_NONSTR(connp)) {
2797 /* Send up T_CONN_CON */
2798 if (ira->ira_cred != NULL) {
2799 mblk_setcred(mp1,
2800 ira->ira_cred,
2801 ira->ira_cpid);
2802 }
2803 putnext(connp->conn_rq, mp1);
2804 } else {
2805 (*sockupcalls->su_connected)
2806 (connp->conn_upper_handle,
2807 tcp->tcp_connid,
2808 ira->ira_cred,
2809 ira->ira_cpid);
2810 freemsg(mp1);
2811 }
2812
2813 freemsg(mp);
2814 return;
2815 }
2816 /*
2817 * Forget fusion; we need to handle more
2818 * complex cases below. Send the deferred
2819 * T_CONN_CON message upstream and proceed
2820 * as usual. Mark this tcp as not capable
2821 * of fusion.
2822 */
2823 TCP_STAT(tcps, tcp_fusion_unfusable);
2824 tcp->tcp_unfusable = B_TRUE;
2825 if (!IPCL_IS_NONSTR(connp)) {
2826 if (ira->ira_cred != NULL) {
2827 mblk_setcred(mp1, ira->ira_cred,
2828 ira->ira_cpid);
2829 }
2830 putnext(connp->conn_rq, mp1);
2831 } else {
2832 (*sockupcalls->su_connected)
2833 (connp->conn_upper_handle,
2834 tcp->tcp_connid, ira->ira_cred,
2835 ira->ira_cpid);
2836 freemsg(mp1);
2837 }
2838 }
2839
2840 /*
2841 * Check to see if there is data to be sent. If
2842 * yes, set the transmit flag. Then check to see
2843 * if received data processing needs to be done.
2844 * If not, go straight to xmit_check. This short
2845 * cut is OK as we don't support T/TCP.
2846 */
2847 if (tcp->tcp_unsent)
2848 flags |= TH_XMIT_NEEDED;
2849
2850 if (seg_len == 0 && !(flags & TH_URG)) {
2851 freemsg(mp);
2852 goto xmit_check;
2853 }
2854
2855 flags &= ~TH_SYN;
2856 seg_seq++;
2857 break;
2858 }
2859 tcp->tcp_state = TCPS_SYN_RCVD;
2860 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
2861 connp->conn_ixa, void_ip_t *, NULL, tcp_t *, tcp,
2862 tcph_t *, NULL, int32_t, TCPS_SYN_SENT);
2863 mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, tcp->tcp_mss,
2864 NULL, NULL, tcp->tcp_iss, B_FALSE, NULL, B_FALSE);
2865 if (mp1 != NULL) {
2866 tcp_send_data(tcp, mp1);
2867 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
2868 }
2869 freemsg(mp);
2870 return;
2871 case TCPS_SYN_RCVD:
2872 if (flags & TH_ACK) {
2873 uint32_t pinit_wnd;
2874
2875 /*
2876 * In this state, a SYN|ACK packet is either bogus
2877 * because the other side must be ACKing our SYN which
2878 * indicates it has seen the ACK for their SYN and
2879 * shouldn't retransmit it or we're crossing SYNs
2880 * on active open.
2881 */
2882 if ((flags & TH_SYN) && !tcp->tcp_active_open) {
2883 freemsg(mp);
2884 tcp_xmit_ctl("TCPS_SYN_RCVD-bad_syn",
2885 tcp, seg_ack, 0, TH_RST);
2886 return;
2887 }
2888 /*
2889 * NOTE: RFC 793 pg. 72 says this should be
2890 * tcp->tcp_suna <= seg_ack <= tcp->tcp_snxt
2891 * but that would mean we have an ack that ignored
2892 * our SYN.
2893 */
2894 if (SEQ_LEQ(seg_ack, tcp->tcp_suna) ||
2895 SEQ_GT(seg_ack, tcp->tcp_snxt)) {
2896 freemsg(mp);
2897 tcp_xmit_ctl("TCPS_SYN_RCVD-bad_ack",
2898 tcp, seg_ack, 0, TH_RST);
2899 return;
2900 }
2901 /*
2902 * No sane TCP stack will send such a small window
2903 * without receiving any data. Just drop this invalid
2904 * ACK. We also shorten the abort timeout in case
2905 * this is an attack.
2906 */
2907 pinit_wnd = ntohs(tcpha->tha_win) << tcp->tcp_snd_ws;
2908 if (pinit_wnd < tcp->tcp_mss &&
2909 pinit_wnd < tcp_init_wnd_chk) {
2910 freemsg(mp);
2911 TCP_STAT(tcps, tcp_zwin_ack_syn);
2912 tcp->tcp_second_ctimer_threshold =
2913 tcp_early_abort * SECONDS;
2914 return;
2915 }
2916 }
2917 break;
2918 case TCPS_LISTEN:
2919 /*
2920 * Only a TLI listener can come through this path when a
2921 * acceptor is going back to be a listener and a packet
2922 * for the acceptor hits the classifier. For a socket
2923 * listener, this can never happen because a listener
2924 * can never accept connection on itself and hence a
2925 * socket acceptor can not go back to being a listener.
2926 */
2927 ASSERT(!TCP_IS_SOCKET(tcp));
2928 /*FALLTHRU*/
2929 case TCPS_CLOSED:
2930 case TCPS_BOUND: {
2931 conn_t *new_connp;
2932 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
2933
2934 /*
2935 * Don't accept any input on a closed tcp as this TCP logically
2936 * does not exist on the system. Don't proceed further with
2937 * this TCP. For instance, this packet could trigger another
2938 * close of this tcp which would be disastrous for tcp_refcnt.
2939 * tcp_close_detached / tcp_clean_death / tcp_closei_local must
2940 * be called at most once on a TCP. In this case we need to
2941 * refeed the packet into the classifier and figure out where
2942 * the packet should go.
2943 */
2944 new_connp = ipcl_classify(mp, ira, ipst);
2945 if (new_connp != NULL) {
2946 /* Drops ref on new_connp */
2947 tcp_reinput(new_connp, mp, ira, ipst);
2948 return;
2949 }
2950 /* We failed to classify. For now just drop the packet */
2951 freemsg(mp);
2952 return;
2953 }
2954 case TCPS_IDLE:
2955 /*
2956 * Handle the case where the tcp_clean_death() has happened
2957 * on a connection (application hasn't closed yet) but a packet
2958 * was already queued on squeue before tcp_clean_death()
2959 * was processed. Calling tcp_clean_death() twice on same
2960 * connection can result in weird behaviour.
2961 */
2962 freemsg(mp);
2963 return;
2964 default:
2965 break;
2966 }
2967
2968 /*
2969 * Already on the correct queue/perimeter.
2970 * If this is a detached connection and not an eager
2971 * connection hanging off a listener then new data
2972 * (past the FIN) will cause a reset.
2973 * We do a special check here where it
2974 * is out of the main line, rather than check
2975 * if we are detached every time we see new
2976 * data down below.
2977 */
2978 if (TCP_IS_DETACHED_NONEAGER(tcp) &&
2979 (seg_len > 0 && SEQ_GT(seg_seq + seg_len, tcp->tcp_rnxt))) {
2980 TCPS_BUMP_MIB(tcps, tcpInClosed);
2981 DTRACE_PROBE2(tcp__trace__recv, mblk_t *, mp, tcp_t *, tcp);
2982 freemsg(mp);
2983 tcp_xmit_ctl("new data when detached", tcp,
2984 tcp->tcp_snxt, 0, TH_RST);
2985 (void) tcp_clean_death(tcp, EPROTO);
2986 return;
2987 }
2988
2989 mp->b_rptr = (uchar_t *)tcpha + TCP_HDR_LENGTH(tcpha);
2990 urp = ntohs(tcpha->tha_urp) - TCP_OLD_URP_INTERPRETATION;
2991 new_swnd = ntohs(tcpha->tha_win) <<
2992 ((tcpha->tha_flags & TH_SYN) ? 0 : tcp->tcp_snd_ws);
2993
2994 /*
2995 * We are interested in two TCP options: timestamps (if negotiated) and
2996 * SACK (if negotiated). Skip option parsing if neither is negotiated.
2997 */
2998 if (tcp->tcp_snd_ts_ok || tcp->tcp_snd_sack_ok) {
2999 int options;
3000 if (tcp->tcp_snd_sack_ok)
3001 tcpopt.tcp = tcp;
3002 else
3003 tcpopt.tcp = NULL;
3004 options = tcp_parse_options(tcpha, &tcpopt);
3005 /*
3006 * RST segments must not be subject to PAWS and are not
3007 * required to have timestamps.
3008 * We do not drop keepalive segments without
3009 * timestamps, to maintain compatibility with legacy TCP stacks.
3010 */
3011 boolean_t keepalive = (seg_len == 0 || seg_len == 1) &&
3012 (seg_seq + 1 == tcp->tcp_rnxt);
3013 if (tcp->tcp_snd_ts_ok && !(flags & TH_RST) && !keepalive) {
3014 /*
3015 * Per RFC 7323 section 3.2., silently drop non-RST
3016 * segments without expected TSopt. This is a 'SHOULD'
3017 * requirement.
3018 * We accept keepalives without TSopt to maintain
3019 * interoperability with tcp implementations that omit
3020 * the TSopt on these. Keepalive data is discarded, so
3021 * there is no risk corrupting data by accepting these.
3022 */
3023 if (!(options & TCP_OPT_TSTAMP_PRESENT)) {
3024 /*
3025 * Leave a breadcrumb for people to detect this
3026 * behavior.
3027 */
3028 DTRACE_TCP1(droppedtimestamp, tcp_t *, tcp);
3029 freemsg(mp);
3030 return;
3031 }
3032
3033 if (!tcp_paws_check(tcp, &tcpopt)) {
3034 /*
3035 * This segment is not acceptable.
3036 * Drop it and send back an ACK.
3037 */
3038 freemsg(mp);
3039 flags |= TH_ACK_NEEDED;
3040 goto ack_check;
3041 }
3042 }
3043 }
3044 try_again:;
3045 mss = tcp->tcp_mss;
3046 gap = seg_seq - tcp->tcp_rnxt;
3047 rgap = tcp->tcp_rwnd - (gap + seg_len);
3048 /*
3049 * gap is the amount of sequence space between what we expect to see
3050 * and what we got for seg_seq. A positive value for gap means
3051 * something got lost. A negative value means we got some old stuff.
3052 */
3053 if (gap < 0) {
3054 /* Old stuff present. Is the SYN in there? */
3055 if (seg_seq == tcp->tcp_irs && (flags & TH_SYN) &&
3056 (seg_len != 0)) {
3057 flags &= ~TH_SYN;
3058 seg_seq++;
3059 urp--;
3060 /* Recompute the gaps after noting the SYN. */
3061 goto try_again;
3062 }
3063 TCPS_BUMP_MIB(tcps, tcpInDataDupSegs);
3064 TCPS_UPDATE_MIB(tcps, tcpInDataDupBytes,
3065 (seg_len > -gap ? -gap : seg_len));
3066 /* Remove the old stuff from seg_len. */
3067 seg_len += gap;
3068 /*
3069 * Anything left?
3070 * Make sure to check for unack'd FIN when rest of data
3071 * has been previously ack'd.
3072 */
3073 if (seg_len < 0 || (seg_len == 0 && !(flags & TH_FIN))) {
3074 /*
3075 * Resets are only valid if they lie within our offered
3076 * window. If the RST bit is set, we just ignore this
3077 * segment.
3078 */
3079 if (flags & TH_RST) {
3080 freemsg(mp);
3081 return;
3082 }
3083
3084 /*
3085 * The arriving of dup data packets indicate that we
3086 * may have postponed an ack for too long, or the other
3087 * side's RTT estimate is out of shape. Start acking
3088 * more often.
3089 */
3090 if (SEQ_GEQ(seg_seq + seg_len - gap, tcp->tcp_rack) &&
3091 tcp->tcp_rack_cnt >= 1 &&
3092 tcp->tcp_rack_abs_max > 2) {
3093 tcp->tcp_rack_abs_max--;
3094 }
3095 tcp->tcp_rack_cur_max = 1;
3096
3097 /*
3098 * This segment is "unacceptable". None of its
3099 * sequence space lies within our advertized window.
3100 *
3101 * Adjust seg_len to the original value for tracing.
3102 */
3103 seg_len -= gap;
3104 if (connp->conn_debug) {
3105 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3106 "tcp_rput: unacceptable, gap %d, rgap %d, "
3107 "flags 0x%x, seg_seq %u, seg_ack %u, "
3108 "seg_len %d, rnxt %u, snxt %u, %s",
3109 gap, rgap, flags, seg_seq, seg_ack,
3110 seg_len, tcp->tcp_rnxt, tcp->tcp_snxt,
3111 tcp_display(tcp, NULL,
3112 DISP_ADDR_AND_PORT));
3113 }
3114
3115 /*
3116 * Arrange to send an ACK in response to the
3117 * unacceptable segment per RFC 793 page 69. There
3118 * is only one small difference between ours and the
3119 * acceptability test in the RFC - we accept ACK-only
3120 * packet with SEG.SEQ = RCV.NXT+RCV.WND and no ACK
3121 * will be generated.
3122 *
3123 * Note that we have to ACK an ACK-only packet at least
3124 * for stacks that send 0-length keep-alives with
3125 * SEG.SEQ = SND.NXT-1 as recommended by RFC1122,
3126 * section 4.2.3.6. As long as we don't ever generate
3127 * an unacceptable packet in response to an incoming
3128 * packet that is unacceptable, it should not cause
3129 * "ACK wars".
3130 */
3131 flags |= TH_ACK_NEEDED;
3132
3133 /*
3134 * Continue processing this segment in order to use the
3135 * ACK information it contains, but skip all other
3136 * sequence-number processing. Processing the ACK
3137 * information is necessary in order to
3138 * re-synchronize connections that may have lost
3139 * synchronization.
3140 *
3141 * We clear seg_len and flag fields related to
3142 * sequence number processing as they are not
3143 * to be trusted for an unacceptable segment.
3144 */
3145 seg_len = 0;
3146 flags &= ~(TH_SYN | TH_FIN | TH_URG);
3147 goto process_ack;
3148 }
3149
3150 /* Fix seg_seq, and chew the gap off the front. */
3151 seg_seq = tcp->tcp_rnxt;
3152 urp += gap;
3153 do {
3154 mblk_t *mp2;
3155 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
3156 (uintptr_t)UINT_MAX);
3157 gap += (uint_t)(mp->b_wptr - mp->b_rptr);
3158 if (gap > 0) {
3159 mp->b_rptr = mp->b_wptr - gap;
3160 break;
3161 }
3162 mp2 = mp;
3163 mp = mp->b_cont;
3164 freeb(mp2);
3165 } while (gap < 0);
3166 /*
3167 * If the urgent data has already been acknowledged, we
3168 * should ignore TH_URG below
3169 */
3170 if (urp < 0)
3171 flags &= ~TH_URG;
3172 }
3173 /*
3174 * rgap is the amount of stuff received out of window. A negative
3175 * value is the amount out of window.
3176 */
3177 if (rgap < 0) {
3178 mblk_t *mp2;
3179
3180 if (tcp->tcp_rwnd == 0) {
3181 TCPS_BUMP_MIB(tcps, tcpInWinProbe);
3182 tcp->tcp_cs.tcp_in_zwnd_probes++;
3183 } else {
3184 TCPS_BUMP_MIB(tcps, tcpInDataPastWinSegs);
3185 TCPS_UPDATE_MIB(tcps, tcpInDataPastWinBytes, -rgap);
3186 }
3187
3188 /*
3189 * seg_len does not include the FIN, so if more than
3190 * just the FIN is out of window, we act like we don't
3191 * see it. (If just the FIN is out of window, rgap
3192 * will be zero and we will go ahead and acknowledge
3193 * the FIN.)
3194 */
3195 flags &= ~TH_FIN;
3196
3197 /* Fix seg_len and make sure there is something left. */
3198 seg_len += rgap;
3199 if (seg_len <= 0) {
3200 /*
3201 * Resets are only valid if they lie within our offered
3202 * window. If the RST bit is set, we just ignore this
3203 * segment.
3204 */
3205 if (flags & TH_RST) {
3206 freemsg(mp);
3207 return;
3208 }
3209
3210 /* Per RFC 793, we need to send back an ACK. */
3211 flags |= TH_ACK_NEEDED;
3212
3213 /*
3214 * Send SIGURG as soon as possible i.e. even
3215 * if the TH_URG was delivered in a window probe
3216 * packet (which will be unacceptable).
3217 *
3218 * We generate a signal if none has been generated
3219 * for this connection or if this is a new urgent
3220 * byte. Also send a zero-length "unmarked" message
3221 * to inform SIOCATMARK that this is not the mark.
3222 *
3223 * tcp_urp_last_valid is cleared when the T_exdata_ind
3224 * is sent up. This plus the check for old data
3225 * (gap >= 0) handles the wraparound of the sequence
3226 * number space without having to always track the
3227 * correct MAX(tcp_urp_last, tcp_rnxt). (BSD tracks
3228 * this max in its rcv_up variable).
3229 *
3230 * This prevents duplicate SIGURGS due to a "late"
3231 * zero-window probe when the T_EXDATA_IND has already
3232 * been sent up.
3233 */
3234 if ((flags & TH_URG) &&
3235 (!tcp->tcp_urp_last_valid || SEQ_GT(urp + seg_seq,
3236 tcp->tcp_urp_last))) {
3237 if (IPCL_IS_NONSTR(connp)) {
3238 if (!TCP_IS_DETACHED(tcp)) {
3239 (*sockupcalls->su_signal_oob)
3240 (connp->conn_upper_handle,
3241 urp);
3242 }
3243 } else {
3244 mp1 = allocb(0, BPRI_MED);
3245 if (mp1 == NULL) {
3246 freemsg(mp);
3247 return;
3248 }
3249 if (!TCP_IS_DETACHED(tcp) &&
3250 !putnextctl1(connp->conn_rq,
3251 M_PCSIG, SIGURG)) {
3252 /* Try again on the rexmit. */
3253 freemsg(mp1);
3254 freemsg(mp);
3255 return;
3256 }
3257 /*
3258 * If the next byte would be the mark
3259 * then mark with MARKNEXT else mark
3260 * with NOTMARKNEXT.
3261 */
3262 if (gap == 0 && urp == 0)
3263 mp1->b_flag |= MSGMARKNEXT;
3264 else
3265 mp1->b_flag |= MSGNOTMARKNEXT;
3266 freemsg(tcp->tcp_urp_mark_mp);
3267 tcp->tcp_urp_mark_mp = mp1;
3268 flags |= TH_SEND_URP_MARK;
3269 }
3270 tcp->tcp_urp_last_valid = B_TRUE;
3271 tcp->tcp_urp_last = urp + seg_seq;
3272 }
3273 /*
3274 * If this is a zero window probe, continue to
3275 * process the ACK part. But we need to set seg_len
3276 * to 0 to avoid data processing. Otherwise just
3277 * drop the segment and send back an ACK.
3278 */
3279 if (tcp->tcp_rwnd == 0 && seg_seq == tcp->tcp_rnxt) {
3280 flags &= ~(TH_SYN | TH_URG);
3281 seg_len = 0;
3282 goto process_ack;
3283 } else {
3284 freemsg(mp);
3285 goto ack_check;
3286 }
3287 }
3288 /* Pitch out of window stuff off the end. */
3289 rgap = seg_len;
3290 mp2 = mp;
3291 do {
3292 ASSERT((uintptr_t)(mp2->b_wptr - mp2->b_rptr) <=
3293 (uintptr_t)INT_MAX);
3294 rgap -= (int)(mp2->b_wptr - mp2->b_rptr);
3295 if (rgap < 0) {
3296 mp2->b_wptr += rgap;
3297 if ((mp1 = mp2->b_cont) != NULL) {
3298 mp2->b_cont = NULL;
3299 freemsg(mp1);
3300 }
3301 break;
3302 }
3303 } while ((mp2 = mp2->b_cont) != NULL);
3304 }
3305 ok:;
3306 /*
3307 * TCP should check ECN info for segments inside the window only.
3308 * Therefore the check should be done here.
3309 */
3310 if (tcp->tcp_ecn_ok) {
3311 if (flags & TH_CWR) {
3312 tcp->tcp_ecn_echo_on = B_FALSE;
3313 }
3314 /*
3315 * Note that both ECN_CE and CWR can be set in the
3316 * same segment. In this case, we once again turn
3317 * on ECN_ECHO.
3318 */
3319 if (connp->conn_ipversion == IPV4_VERSION) {
3320 uchar_t tos = ((ipha_t *)rptr)->ipha_type_of_service;
3321
3322 if ((tos & IPH_ECN_CE) == IPH_ECN_CE) {
3323 tcp->tcp_ecn_echo_on = B_TRUE;
3324 }
3325 } else {
3326 uint32_t vcf = ((ip6_t *)rptr)->ip6_vcf;
3327
3328 if ((vcf & htonl(IPH_ECN_CE << 20)) ==
3329 htonl(IPH_ECN_CE << 20)) {
3330 tcp->tcp_ecn_echo_on = B_TRUE;
3331 }
3332 }
3333 }
3334
3335 /*
3336 * Check whether we can update tcp_ts_recent. This test is from RFC
3337 * 7323, section 5.3.
3338 */
3339 if (tcp->tcp_snd_ts_ok && !(flags & TH_RST) &&
3340 TSTMP_GEQ(tcpopt.tcp_opt_ts_val, tcp->tcp_ts_recent) &&
3341 SEQ_LEQ(seg_seq, tcp->tcp_rack)) {
3342 tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val;
3343 tcp->tcp_last_rcv_lbolt = LBOLT_FASTPATH64;
3344 }
3345
3346 if (seg_seq != tcp->tcp_rnxt || tcp->tcp_reass_head) {
3347 /*
3348 * FIN in an out of order segment. We record this in
3349 * tcp_valid_bits and the seq num of FIN in tcp_ofo_fin_seq.
3350 * Clear the FIN so that any check on FIN flag will fail.
3351 * Remember that FIN also counts in the sequence number
3352 * space. So we need to ack out of order FIN only segments.
3353 */
3354 if (flags & TH_FIN) {
3355 tcp->tcp_valid_bits |= TCP_OFO_FIN_VALID;
3356 tcp->tcp_ofo_fin_seq = seg_seq + seg_len;
3357 flags &= ~TH_FIN;
3358 flags |= TH_ACK_NEEDED;
3359 }
3360 if (seg_len > 0) {
3361 /* Fill in the SACK blk list. */
3362 if (tcp->tcp_snd_sack_ok) {
3363 tcp_sack_insert(tcp->tcp_sack_list,
3364 seg_seq, seg_seq + seg_len,
3365 &(tcp->tcp_num_sack_blk));
3366 }
3367
3368 /*
3369 * Attempt reassembly and see if we have something
3370 * ready to go.
3371 */
3372 mp = tcp_reass(tcp, mp, seg_seq);
3373 /* Always ack out of order packets */
3374 flags |= TH_ACK_NEEDED | TH_PUSH;
3375 if (mp) {
3376 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
3377 (uintptr_t)INT_MAX);
3378 seg_len = mp->b_cont ? msgdsize(mp) :
3379 (int)(mp->b_wptr - mp->b_rptr);
3380 seg_seq = tcp->tcp_rnxt;
3381 /*
3382 * A gap is filled and the seq num and len
3383 * of the gap match that of a previously
3384 * received FIN, put the FIN flag back in.
3385 */
3386 if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) &&
3387 seg_seq + seg_len == tcp->tcp_ofo_fin_seq) {
3388 flags |= TH_FIN;
3389 tcp->tcp_valid_bits &=
3390 ~TCP_OFO_FIN_VALID;
3391 }
3392 if (tcp->tcp_reass_tid != 0) {
3393 (void) TCP_TIMER_CANCEL(tcp,
3394 tcp->tcp_reass_tid);
3395 /*
3396 * Restart the timer if there is still
3397 * data in the reassembly queue.
3398 */
3399 if (tcp->tcp_reass_head != NULL) {
3400 tcp->tcp_reass_tid = TCP_TIMER(
3401 tcp, tcp_reass_timer,
3402 tcps->tcps_reass_timeout);
3403 } else {
3404 tcp->tcp_reass_tid = 0;
3405 }
3406 }
3407 } else {
3408 /*
3409 * Keep going even with NULL mp.
3410 * There may be a useful ACK or something else
3411 * we don't want to miss.
3412 *
3413 * But TCP should not perform fast retransmit
3414 * because of the ack number. TCP uses
3415 * seg_len == 0 to determine if it is a pure
3416 * ACK. And this is not a pure ACK.
3417 */
3418 seg_len = 0;
3419 ofo_seg = B_TRUE;
3420
3421 if (tcps->tcps_reass_timeout != 0 &&
3422 tcp->tcp_reass_tid == 0) {
3423 tcp->tcp_reass_tid = TCP_TIMER(tcp,
3424 tcp_reass_timer,
3425 tcps->tcps_reass_timeout);
3426 }
3427 }
3428 }
3429 } else if (seg_len > 0) {
3430 TCPS_BUMP_MIB(tcps, tcpInDataInorderSegs);
3431 TCPS_UPDATE_MIB(tcps, tcpInDataInorderBytes, seg_len);
3432 tcp->tcp_cs.tcp_in_data_inorder_segs++;
3433 tcp->tcp_cs.tcp_in_data_inorder_bytes += seg_len;
3434
3435 /*
3436 * If an out of order FIN was received before, and the seq
3437 * num and len of the new segment match that of the FIN,
3438 * put the FIN flag back in.
3439 */
3440 if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) &&
3441 seg_seq + seg_len == tcp->tcp_ofo_fin_seq) {
3442 flags |= TH_FIN;
3443 tcp->tcp_valid_bits &= ~TCP_OFO_FIN_VALID;
3444 }
3445 }
3446 if ((flags & (TH_RST | TH_SYN | TH_URG | TH_ACK)) != TH_ACK) {
3447 if (flags & TH_RST) {
3448 freemsg(mp);
3449 switch (tcp->tcp_state) {
3450 case TCPS_SYN_RCVD:
3451 (void) tcp_clean_death(tcp, ECONNREFUSED);
3452 break;
3453 case TCPS_ESTABLISHED:
3454 case TCPS_FIN_WAIT_1:
3455 case TCPS_FIN_WAIT_2:
3456 case TCPS_CLOSE_WAIT:
3457 (void) tcp_clean_death(tcp, ECONNRESET);
3458 break;
3459 case TCPS_CLOSING:
3460 case TCPS_LAST_ACK:
3461 (void) tcp_clean_death(tcp, 0);
3462 break;
3463 default:
3464 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
3465 (void) tcp_clean_death(tcp, ENXIO);
3466 break;
3467 }
3468 return;
3469 }
3470 if (flags & TH_SYN) {
3471 /*
3472 * See RFC 793, Page 71
3473 *
3474 * The seq number must be in the window as it should
3475 * be "fixed" above. If it is outside window, it should
3476 * be already rejected. Note that we allow seg_seq to be
3477 * rnxt + rwnd because we want to accept 0 window probe.
3478 */
3479 ASSERT(SEQ_GEQ(seg_seq, tcp->tcp_rnxt) &&
3480 SEQ_LEQ(seg_seq, tcp->tcp_rnxt + tcp->tcp_rwnd));
3481 freemsg(mp);
3482 /*
3483 * If the ACK flag is not set, just use our snxt as the
3484 * seq number of the RST segment.
3485 */
3486 if (!(flags & TH_ACK)) {
3487 seg_ack = tcp->tcp_snxt;
3488 }
3489 tcp_xmit_ctl("TH_SYN", tcp, seg_ack, seg_seq + 1,
3490 TH_RST|TH_ACK);
3491 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
3492 (void) tcp_clean_death(tcp, ECONNRESET);
3493 return;
3494 }
3495 /*
3496 * urp could be -1 when the urp field in the packet is 0
3497 * and TCP_OLD_URP_INTERPRETATION is set. This implies that the urgent
3498 * byte was at seg_seq - 1, in which case we ignore the urgent flag.
3499 */
3500 if ((flags & TH_URG) && urp >= 0) {
3501 if (!tcp->tcp_urp_last_valid ||
3502 SEQ_GT(urp + seg_seq, tcp->tcp_urp_last)) {
3503 /*
3504 * Non-STREAMS sockets handle the urgent data a litte
3505 * differently from STREAMS based sockets. There is no
3506 * need to mark any mblks with the MSG{NOT,}MARKNEXT
3507 * flags to keep SIOCATMARK happy. Instead a
3508 * su_signal_oob upcall is made to update the mark.
3509 * Neither is a T_EXDATA_IND mblk needed to be
3510 * prepended to the urgent data. The urgent data is
3511 * delivered using the su_recv upcall, where we set
3512 * the MSG_OOB flag to indicate that it is urg data.
3513 *
3514 * Neither TH_SEND_URP_MARK nor TH_MARKNEXT_NEEDED
3515 * are used by non-STREAMS sockets.
3516 */
3517 if (IPCL_IS_NONSTR(connp)) {
3518 if (!TCP_IS_DETACHED(tcp)) {
3519 (*sockupcalls->su_signal_oob)
3520 (connp->conn_upper_handle, urp);
3521 }
3522 } else {
3523 /*
3524 * If we haven't generated the signal yet for
3525 * this urgent pointer value, do it now. Also,
3526 * send up a zero-length M_DATA indicating
3527 * whether or not this is the mark. The latter
3528 * is not needed when a T_EXDATA_IND is sent up.
3529 * However, if there are allocation failures
3530 * this code relies on the sender retransmitting
3531 * and the socket code for determining the mark
3532 * should not block waiting for the peer to
3533 * transmit. Thus, for simplicity we always
3534 * send up the mark indication.
3535 */
3536 mp1 = allocb(0, BPRI_MED);
3537 if (mp1 == NULL) {
3538 freemsg(mp);
3539 return;
3540 }
3541 if (!TCP_IS_DETACHED(tcp) &&
3542 !putnextctl1(connp->conn_rq, M_PCSIG,
3543 SIGURG)) {
3544 /* Try again on the rexmit. */
3545 freemsg(mp1);
3546 freemsg(mp);
3547 return;
3548 }
3549 /*
3550 * Mark with NOTMARKNEXT for now.
3551 * The code below will change this to MARKNEXT
3552 * if we are at the mark.
3553 *
3554 * If there are allocation failures (e.g. in
3555 * dupmsg below) the next time tcp_input_data
3556 * sees the urgent segment it will send up the
3557 * MSGMARKNEXT message.
3558 */
3559 mp1->b_flag |= MSGNOTMARKNEXT;
3560 freemsg(tcp->tcp_urp_mark_mp);
3561 tcp->tcp_urp_mark_mp = mp1;
3562 flags |= TH_SEND_URP_MARK;
3563 #ifdef DEBUG
3564 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3565 "tcp_rput: sent M_PCSIG 2 seq %x urp %x "
3566 "last %x, %s",
3567 seg_seq, urp, tcp->tcp_urp_last,
3568 tcp_display(tcp, NULL, DISP_PORT_ONLY));
3569 #endif /* DEBUG */
3570 }
3571 tcp->tcp_urp_last_valid = B_TRUE;
3572 tcp->tcp_urp_last = urp + seg_seq;
3573 } else if (tcp->tcp_urp_mark_mp != NULL) {
3574 /*
3575 * An allocation failure prevented the previous
3576 * tcp_input_data from sending up the allocated
3577 * MSG*MARKNEXT message - send it up this time
3578 * around.
3579 */
3580 flags |= TH_SEND_URP_MARK;
3581 }
3582
3583 /*
3584 * If the urgent byte is in this segment, make sure that it is
3585 * all by itself. This makes it much easier to deal with the
3586 * possibility of an allocation failure on the T_exdata_ind.
3587 * Note that seg_len is the number of bytes in the segment, and
3588 * urp is the offset into the segment of the urgent byte.
3589 * urp < seg_len means that the urgent byte is in this segment.
3590 */
3591 if (urp < seg_len) {
3592 if (seg_len != 1) {
3593 uint32_t tmp_rnxt;
3594 /*
3595 * Break it up and feed it back in.
3596 * Re-attach the IP header.
3597 */
3598 mp->b_rptr = iphdr;
3599 if (urp > 0) {
3600 /*
3601 * There is stuff before the urgent
3602 * byte.
3603 */
3604 mp1 = dupmsg(mp);
3605 if (!mp1) {
3606 /*
3607 * Trim from urgent byte on.
3608 * The rest will come back.
3609 */
3610 (void) adjmsg(mp,
3611 urp - seg_len);
3612 tcp_input_data(connp,
3613 mp, NULL, ira);
3614 return;
3615 }
3616 (void) adjmsg(mp1, urp - seg_len);
3617 /* Feed this piece back in. */
3618 tmp_rnxt = tcp->tcp_rnxt;
3619 tcp_input_data(connp, mp1, NULL, ira);
3620 /*
3621 * If the data passed back in was not
3622 * processed (ie: bad ACK) sending
3623 * the remainder back in will cause a
3624 * loop. In this case, drop the
3625 * packet and let the sender try
3626 * sending a good packet.
3627 */
3628 if (tmp_rnxt == tcp->tcp_rnxt) {
3629 freemsg(mp);
3630 return;
3631 }
3632 }
3633 if (urp != seg_len - 1) {
3634 uint32_t tmp_rnxt;
3635 /*
3636 * There is stuff after the urgent
3637 * byte.
3638 */
3639 mp1 = dupmsg(mp);
3640 if (!mp1) {
3641 /*
3642 * Trim everything beyond the
3643 * urgent byte. The rest will
3644 * come back.
3645 */
3646 (void) adjmsg(mp,
3647 urp + 1 - seg_len);
3648 tcp_input_data(connp,
3649 mp, NULL, ira);
3650 return;
3651 }
3652 (void) adjmsg(mp1, urp + 1 - seg_len);
3653 tmp_rnxt = tcp->tcp_rnxt;
3654 tcp_input_data(connp, mp1, NULL, ira);
3655 /*
3656 * If the data passed back in was not
3657 * processed (ie: bad ACK) sending
3658 * the remainder back in will cause a
3659 * loop. In this case, drop the
3660 * packet and let the sender try
3661 * sending a good packet.
3662 */
3663 if (tmp_rnxt == tcp->tcp_rnxt) {
3664 freemsg(mp);
3665 return;
3666 }
3667 }
3668 tcp_input_data(connp, mp, NULL, ira);
3669 return;
3670 }
3671 /*
3672 * This segment contains only the urgent byte. We
3673 * have to allocate the T_exdata_ind, if we can.
3674 */
3675 if (IPCL_IS_NONSTR(connp)) {
3676 int error;
3677
3678 (*sockupcalls->su_recv)
3679 (connp->conn_upper_handle, mp, seg_len,
3680 MSG_OOB, &error, NULL);
3681 /*
3682 * We should never be in middle of a
3683 * fallback, the squeue guarantees that.
3684 */
3685 ASSERT(error != EOPNOTSUPP);
3686 mp = NULL;
3687 goto update_ack;
3688 } else if (!tcp->tcp_urp_mp) {
3689 struct T_exdata_ind *tei;
3690 mp1 = allocb(sizeof (struct T_exdata_ind),
3691 BPRI_MED);
3692 if (!mp1) {
3693 /*
3694 * Sigh... It'll be back.
3695 * Generate any MSG*MARK message now.
3696 */
3697 freemsg(mp);
3698 seg_len = 0;
3699 if (flags & TH_SEND_URP_MARK) {
3700
3701
3702 ASSERT(tcp->tcp_urp_mark_mp);
3703 tcp->tcp_urp_mark_mp->b_flag &=
3704 ~MSGNOTMARKNEXT;
3705 tcp->tcp_urp_mark_mp->b_flag |=
3706 MSGMARKNEXT;
3707 }
3708 goto ack_check;
3709 }
3710 mp1->b_datap->db_type = M_PROTO;
3711 tei = (struct T_exdata_ind *)mp1->b_rptr;
3712 tei->PRIM_type = T_EXDATA_IND;
3713 tei->MORE_flag = 0;
3714 mp1->b_wptr = (uchar_t *)&tei[1];
3715 tcp->tcp_urp_mp = mp1;
3716 #ifdef DEBUG
3717 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3718 "tcp_rput: allocated exdata_ind %s",
3719 tcp_display(tcp, NULL,
3720 DISP_PORT_ONLY));
3721 #endif /* DEBUG */
3722 /*
3723 * There is no need to send a separate MSG*MARK
3724 * message since the T_EXDATA_IND will be sent
3725 * now.
3726 */
3727 flags &= ~TH_SEND_URP_MARK;
3728 freemsg(tcp->tcp_urp_mark_mp);
3729 tcp->tcp_urp_mark_mp = NULL;
3730 }
3731 /*
3732 * Now we are all set. On the next putnext upstream,
3733 * tcp_urp_mp will be non-NULL and will get prepended
3734 * to what has to be this piece containing the urgent
3735 * byte. If for any reason we abort this segment below,
3736 * if it comes back, we will have this ready, or it
3737 * will get blown off in close.
3738 */
3739 } else if (urp == seg_len) {
3740 /*
3741 * The urgent byte is the next byte after this sequence
3742 * number. If this endpoint is non-STREAMS, then there
3743 * is nothing to do here since the socket has already
3744 * been notified about the urg pointer by the
3745 * su_signal_oob call above.
3746 *
3747 * In case of STREAMS, some more work might be needed.
3748 * If there is data it is marked with MSGMARKNEXT and
3749 * and any tcp_urp_mark_mp is discarded since it is not
3750 * needed. Otherwise, if the code above just allocated
3751 * a zero-length tcp_urp_mark_mp message, that message
3752 * is tagged with MSGMARKNEXT. Sending up these
3753 * MSGMARKNEXT messages makes SIOCATMARK work correctly
3754 * even though the T_EXDATA_IND will not be sent up
3755 * until the urgent byte arrives.
3756 */
3757 if (!IPCL_IS_NONSTR(tcp->tcp_connp)) {
3758 if (seg_len != 0) {
3759 flags |= TH_MARKNEXT_NEEDED;
3760 freemsg(tcp->tcp_urp_mark_mp);
3761 tcp->tcp_urp_mark_mp = NULL;
3762 flags &= ~TH_SEND_URP_MARK;
3763 } else if (tcp->tcp_urp_mark_mp != NULL) {
3764 flags |= TH_SEND_URP_MARK;
3765 tcp->tcp_urp_mark_mp->b_flag &=
3766 ~MSGNOTMARKNEXT;
3767 tcp->tcp_urp_mark_mp->b_flag |=
3768 MSGMARKNEXT;
3769 }
3770 }
3771 #ifdef DEBUG
3772 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3773 "tcp_rput: AT MARK, len %d, flags 0x%x, %s",
3774 seg_len, flags,
3775 tcp_display(tcp, NULL, DISP_PORT_ONLY));
3776 #endif /* DEBUG */
3777 }
3778 #ifdef DEBUG
3779 else {
3780 /* Data left until we hit mark */
3781 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
3782 "tcp_rput: URP %d bytes left, %s",
3783 urp - seg_len, tcp_display(tcp, NULL,
3784 DISP_PORT_ONLY));
3785 }
3786 #endif /* DEBUG */
3787 }
3788
3789 process_ack:
3790 if (!(flags & TH_ACK)) {
3791 freemsg(mp);
3792 goto xmit_check;
3793 }
3794 }
3795 bytes_acked = (int)(seg_ack - tcp->tcp_suna);
3796
3797 if (bytes_acked > 0)
3798 tcp->tcp_ip_forward_progress = B_TRUE;
3799 if (tcp->tcp_state == TCPS_SYN_RCVD) {
3800 /*
3801 * tcp_sendmsg() checks tcp_state without entering
3802 * the squeue so tcp_state should be updated before
3803 * sending up a connection confirmation or a new
3804 * connection indication.
3805 */
3806 tcp->tcp_state = TCPS_ESTABLISHED;
3807
3808 /*
3809 * We are seeing the final ack in the three way
3810 * hand shake of a active open'ed connection
3811 * so we must send up a T_CONN_CON
3812 */
3813 if (tcp->tcp_active_open) {
3814 if (!tcp_conn_con(tcp, iphdr, mp, NULL, ira)) {
3815 freemsg(mp);
3816 tcp->tcp_state = TCPS_SYN_RCVD;
3817 return;
3818 }
3819 /*
3820 * Don't fuse the loopback endpoints for
3821 * simultaneous active opens.
3822 */
3823 if (tcp->tcp_loopback) {
3824 TCP_STAT(tcps, tcp_fusion_unfusable);
3825 tcp->tcp_unfusable = B_TRUE;
3826 }
3827 /*
3828 * For simultaneous active open, trace receipt of final
3829 * ACK as tcp:::connect-established.
3830 */
3831 DTRACE_TCP5(connect__established, mblk_t *, NULL,
3832 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3833 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3834 } else if (IPCL_IS_NONSTR(connp)) {
3835 /*
3836 * 3-way handshake has completed, so notify socket
3837 * of the new connection.
3838 *
3839 * We are here means eager is fine but it can
3840 * get a TH_RST at any point between now and till
3841 * accept completes and disappear. We need to
3842 * ensure that reference to eager is valid after
3843 * we get out of eager's perimeter. So we do
3844 * an extra refhold.
3845 */
3846 CONN_INC_REF(connp);
3847
3848 if (!tcp_newconn_notify(tcp, ira)) {
3849 /*
3850 * The state-change probe for SYN_RCVD ->
3851 * ESTABLISHED has not fired yet. We reset
3852 * the state to SYN_RCVD so that future
3853 * state-change probes report correct state
3854 * transistions.
3855 */
3856 tcp->tcp_state = TCPS_SYN_RCVD;
3857 freemsg(mp);
3858 /* notification did not go up, so drop ref */
3859 CONN_DEC_REF(connp);
3860 /* ... and close the eager */
3861 ASSERT(TCP_IS_DETACHED(tcp));
3862 (void) tcp_close_detached(tcp);
3863 return;
3864 }
3865 /*
3866 * tcp_newconn_notify() changes conn_upcalls and
3867 * connp->conn_upper_handle. Fix things now, in case
3868 * there's data attached to this ack.
3869 */
3870 if (connp->conn_upcalls != NULL)
3871 sockupcalls = connp->conn_upcalls;
3872 /*
3873 * For passive open, trace receipt of final ACK as
3874 * tcp:::accept-established.
3875 */
3876 DTRACE_TCP5(accept__established, mlbk_t *, NULL,
3877 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3878 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3879 } else {
3880 /*
3881 * 3-way handshake complete - this is a STREAMS based
3882 * socket, so pass up the T_CONN_IND.
3883 */
3884 tcp_t *listener = tcp->tcp_listener;
3885 mblk_t *mp = tcp->tcp_conn.tcp_eager_conn_ind;
3886
3887 tcp->tcp_tconnind_started = B_TRUE;
3888 tcp->tcp_conn.tcp_eager_conn_ind = NULL;
3889 ASSERT(mp != NULL);
3890 /*
3891 * We are here means eager is fine but it can
3892 * get a TH_RST at any point between now and till
3893 * accept completes and disappear. We need to
3894 * ensure that reference to eager is valid after
3895 * we get out of eager's perimeter. So we do
3896 * an extra refhold.
3897 */
3898 CONN_INC_REF(connp);
3899
3900 /*
3901 * The listener also exists because of the refhold
3902 * done in tcp_input_listener. Its possible that it
3903 * might have closed. We will check that once we
3904 * get inside listeners context.
3905 */
3906 CONN_INC_REF(listener->tcp_connp);
3907 if (listener->tcp_connp->conn_sqp ==
3908 connp->conn_sqp) {
3909 /*
3910 * We optimize by not calling an SQUEUE_ENTER
3911 * on the listener since we know that the
3912 * listener and eager squeues are the same.
3913 * We are able to make this check safely only
3914 * because neither the eager nor the listener
3915 * can change its squeue. Only an active connect
3916 * can change its squeue
3917 */
3918 tcp_send_conn_ind(listener->tcp_connp, mp,
3919 listener->tcp_connp->conn_sqp);
3920 CONN_DEC_REF(listener->tcp_connp);
3921 } else if (!tcp->tcp_loopback) {
3922 SQUEUE_ENTER_ONE(listener->tcp_connp->conn_sqp,
3923 mp, tcp_send_conn_ind,
3924 listener->tcp_connp, NULL, SQ_FILL,
3925 SQTAG_TCP_CONN_IND);
3926 } else {
3927 SQUEUE_ENTER_ONE(listener->tcp_connp->conn_sqp,
3928 mp, tcp_send_conn_ind,
3929 listener->tcp_connp, NULL, SQ_NODRAIN,
3930 SQTAG_TCP_CONN_IND);
3931 }
3932 /*
3933 * For passive open, trace receipt of final ACK as
3934 * tcp:::accept-established.
3935 */
3936 DTRACE_TCP5(accept__established, mlbk_t *, NULL,
3937 ip_xmit_attr_t *, connp->conn_ixa, void_ip_t *,
3938 iphdr, tcp_t *, tcp, tcph_t *, tcpha);
3939 }
3940 TCPS_CONN_INC(tcps);
3941
3942 tcp->tcp_suna = tcp->tcp_iss + 1; /* One for the SYN */
3943 bytes_acked--;
3944 /* SYN was acked - making progress */
3945 tcp->tcp_ip_forward_progress = B_TRUE;
3946
3947 /*
3948 * If SYN was retransmitted, need to reset all
3949 * retransmission info as this segment will be
3950 * treated as a dup ACK.
3951 */
3952 if (tcp->tcp_rexmit) {
3953 tcp->tcp_rexmit = B_FALSE;
3954 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
3955 tcp->tcp_rexmit_max = tcp->tcp_snxt;
3956 tcp->tcp_ms_we_have_waited = 0;
3957 DTRACE_PROBE3(cwnd__retransmitted__syn,
3958 tcp_t *, tcp, uint32_t, tcp->tcp_cwnd,
3959 uint32_t, tcp->tcp_mss);
3960 tcp->tcp_cwnd = mss;
3961 }
3962
3963 /*
3964 * We set the send window to zero here.
3965 * This is needed if there is data to be
3966 * processed already on the queue.
3967 * Later (at swnd_update label), the
3968 * "new_swnd > tcp_swnd" condition is satisfied
3969 * the XMIT_NEEDED flag is set in the current
3970 * (SYN_RCVD) state. This ensures tcp_wput_data() is
3971 * called if there is already data on queue in
3972 * this state.
3973 */
3974 tcp->tcp_swnd = 0;
3975
3976 if (new_swnd > tcp->tcp_max_swnd)
3977 tcp->tcp_max_swnd = new_swnd;
3978 tcp->tcp_swl1 = seg_seq;
3979 tcp->tcp_swl2 = seg_ack;
3980 tcp->tcp_valid_bits &= ~TCP_ISS_VALID;
3981
3982 /* Trace change from SYN_RCVD -> ESTABLISHED here */
3983 DTRACE_TCP6(state__change, void, NULL, ip_xmit_attr_t *,
3984 connp->conn_ixa, void, NULL, tcp_t *, tcp, void, NULL,
3985 int32_t, TCPS_SYN_RCVD);
3986
3987 /* Fuse when both sides are in ESTABLISHED state */
3988 if (tcp->tcp_loopback && do_tcp_fusion)
3989 tcp_fuse(tcp, iphdr, tcpha);
3990
3991 }
3992 /* This code follows 4.4BSD-Lite2 mostly. */
3993 if (bytes_acked < 0)
3994 goto est;
3995
3996 /*
3997 * If TCP is ECN capable and the congestion experience bit is
3998 * set, reduce tcp_cwnd and tcp_ssthresh. But this should only be
3999 * done once per window (or more loosely, per RTT).
4000 */
4001 if (tcp->tcp_cwr && SEQ_GT(seg_ack, tcp->tcp_cwr_snd_max))
4002 tcp->tcp_cwr = B_FALSE;
4003 if (tcp->tcp_ecn_ok && (flags & TH_ECE) && !tcp->tcp_cwr) {
4004 cc_cong_signal(tcp, seg_ack, CC_ECN);
4005 /*
4006 * If the cwnd is 0, use the timer to clock out
4007 * new segments. This is required by the ECN spec.
4008 */
4009 if (tcp->tcp_cwnd == 0)
4010 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
4011 tcp->tcp_cwr = B_TRUE;
4012 /*
4013 * This marks the end of the current window of in
4014 * flight data. That is why we don't use
4015 * tcp_suna + tcp_swnd. Only data in flight can
4016 * provide ECN info.
4017 */
4018 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
4019 }
4020
4021 mp1 = tcp->tcp_xmit_head;
4022 if (bytes_acked == 0) {
4023 if (!ofo_seg && seg_len == 0 && new_swnd == tcp->tcp_swnd) {
4024 int dupack_cnt;
4025
4026 TCPS_BUMP_MIB(tcps, tcpInDupAck);
4027 /*
4028 * Fast retransmit. When we have seen exactly three
4029 * identical ACKs while we have unacked data
4030 * outstanding we take it as a hint that our peer
4031 * dropped something.
4032 *
4033 * If TCP is retransmitting, don't do fast retransmit.
4034 */
4035 if (mp1 && tcp->tcp_suna != tcp->tcp_snxt &&
4036 ! tcp->tcp_rexmit) {
4037 /* Do Limited Transmit */
4038 if ((dupack_cnt = ++tcp->tcp_dupack_cnt) <
4039 tcps->tcps_dupack_fast_retransmit) {
4040 cc_ack_received(tcp, seg_ack,
4041 bytes_acked, CC_DUPACK);
4042 /*
4043 * RFC 3042
4044 *
4045 * What we need to do is temporarily
4046 * increase tcp_cwnd so that new
4047 * data can be sent if it is allowed
4048 * by the receive window (tcp_rwnd).
4049 * tcp_wput_data() will take care of
4050 * the rest.
4051 *
4052 * If the connection is SACK capable,
4053 * only do limited xmit when there
4054 * is SACK info.
4055 *
4056 * Note how tcp_cwnd is incremented.
4057 * The first dup ACK will increase
4058 * it by 1 MSS. The second dup ACK
4059 * will increase it by 2 MSS. This
4060 * means that only 1 new segment will
4061 * be sent for each dup ACK.
4062 */
4063 if (tcp->tcp_unsent > 0 &&
4064 (!tcp->tcp_snd_sack_ok ||
4065 (tcp->tcp_snd_sack_ok &&
4066 tcp->tcp_notsack_list != NULL))) {
4067 tcp->tcp_cwnd += mss <<
4068 (tcp->tcp_dupack_cnt - 1);
4069 flags |= TH_LIMIT_XMIT;
4070 }
4071 } else if (dupack_cnt ==
4072 tcps->tcps_dupack_fast_retransmit) {
4073
4074 /*
4075 * If we have reduced tcp_ssthresh
4076 * because of ECN, do not reduce it again
4077 * unless it is already one window of data
4078 * away. After one window of data, tcp_cwr
4079 * should then be cleared. Note that
4080 * for non ECN capable connection, tcp_cwr
4081 * should always be false.
4082 *
4083 * Adjust cwnd since the duplicate
4084 * ack indicates that a packet was
4085 * dropped (due to congestion.)
4086 */
4087 if (!tcp->tcp_cwr) {
4088 cc_cong_signal(tcp, seg_ack,
4089 CC_NDUPACK);
4090 cc_ack_received(tcp, seg_ack,
4091 bytes_acked, CC_DUPACK);
4092 }
4093 if (tcp->tcp_ecn_ok) {
4094 tcp->tcp_cwr = B_TRUE;
4095 tcp->tcp_cwr_snd_max = tcp->tcp_snxt;
4096 tcp->tcp_ecn_cwr_sent = B_FALSE;
4097 }
4098
4099 /*
4100 * We do Hoe's algorithm. Refer to her
4101 * paper "Improving the Start-up Behavior
4102 * of a Congestion Control Scheme for TCP,"
4103 * appeared in SIGCOMM'96.
4104 *
4105 * Save highest seq no we have sent so far.
4106 * Be careful about the invisible FIN byte.
4107 */
4108 if ((tcp->tcp_valid_bits & TCP_FSS_VALID) &&
4109 (tcp->tcp_unsent == 0)) {
4110 tcp->tcp_rexmit_max = tcp->tcp_fss;
4111 } else {
4112 tcp->tcp_rexmit_max = tcp->tcp_snxt;
4113 }
4114
4115 /*
4116 * For SACK:
4117 * Calculate tcp_pipe, which is the
4118 * estimated number of bytes in
4119 * network.
4120 *
4121 * tcp_fack is the highest sack'ed seq num
4122 * TCP has received.
4123 *
4124 * tcp_pipe is explained in the above quoted
4125 * Fall and Floyd's paper. tcp_fack is
4126 * explained in Mathis and Mahdavi's
4127 * "Forward Acknowledgment: Refining TCP
4128 * Congestion Control" in SIGCOMM '96.
4129 */
4130 if (tcp->tcp_snd_sack_ok) {
4131 if (tcp->tcp_notsack_list != NULL) {
4132 tcp->tcp_pipe = tcp->tcp_snxt -
4133 tcp->tcp_fack;
4134 tcp->tcp_sack_snxt = seg_ack;
4135 flags |= TH_NEED_SACK_REXMIT;
4136 } else {
4137 /*
4138 * Always initialize tcp_pipe
4139 * even though we don't have
4140 * any SACK info. If later
4141 * we get SACK info and
4142 * tcp_pipe is not initialized,
4143 * funny things will happen.
4144 */
4145 tcp->tcp_pipe =
4146 tcp->tcp_cwnd_ssthresh;
4147 }
4148 } else {
4149 flags |= TH_REXMIT_NEEDED;
4150 } /* tcp_snd_sack_ok */
4151
4152 } else {
4153 cc_ack_received(tcp, seg_ack,
4154 bytes_acked, CC_DUPACK);
4155 /*
4156 * Here we perform congestion
4157 * avoidance, but NOT slow start.
4158 * This is known as the Fast
4159 * Recovery Algorithm.
4160 */
4161 if (tcp->tcp_snd_sack_ok &&
4162 tcp->tcp_notsack_list != NULL) {
4163 flags |= TH_NEED_SACK_REXMIT;
4164 tcp->tcp_pipe -= mss;
4165 if (tcp->tcp_pipe < 0)
4166 tcp->tcp_pipe = 0;
4167 } else {
4168 /*
4169 * We know that one more packet has
4170 * left the pipe thus we can update
4171 * cwnd.
4172 */
4173 cwnd = tcp->tcp_cwnd + mss;
4174 if (cwnd > tcp->tcp_cwnd_max)
4175 cwnd = tcp->tcp_cwnd_max;
4176 DTRACE_PROBE3(cwnd__fast__recovery,
4177 tcp_t *, tcp,
4178 uint32_t, tcp->tcp_cwnd,
4179 uint32_t, cwnd);
4180 tcp->tcp_cwnd = cwnd;
4181 if (tcp->tcp_unsent > 0)
4182 flags |= TH_XMIT_NEEDED;
4183 }
4184 }
4185 }
4186 } else if (tcp->tcp_zero_win_probe) {
4187 /*
4188 * If the window has opened, need to arrange
4189 * to send additional data.
4190 */
4191 if (new_swnd != 0) {
4192 /* tcp_suna != tcp_snxt */
4193 /* Packet contains a window update */
4194 TCPS_BUMP_MIB(tcps, tcpInWinUpdate);
4195 tcp->tcp_zero_win_probe = 0;
4196 tcp->tcp_timer_backoff = 0;
4197 tcp->tcp_ms_we_have_waited = 0;
4198
4199 /*
4200 * Transmit starting with tcp_suna since
4201 * the one byte probe is not ack'ed.
4202 * If TCP has sent more than one identical
4203 * probe, tcp_rexmit will be set. That means
4204 * tcp_ss_rexmit() will send out the one
4205 * byte along with new data. Otherwise,
4206 * fake the retransmission.
4207 */
4208 flags |= TH_XMIT_NEEDED;
4209 if (!tcp->tcp_rexmit) {
4210 tcp->tcp_rexmit = B_TRUE;
4211 tcp->tcp_dupack_cnt = 0;
4212 tcp->tcp_rexmit_nxt = tcp->tcp_suna;
4213 tcp->tcp_rexmit_max = tcp->tcp_suna + 1;
4214 }
4215 }
4216 }
4217 goto swnd_update;
4218 }
4219
4220 /*
4221 * Check for "acceptability" of ACK value per RFC 793, pages 72 - 73.
4222 * If the ACK value acks something that we have not yet sent, it might
4223 * be an old duplicate segment. Send an ACK to re-synchronize the
4224 * other side.
4225 * Note: reset in response to unacceptable ACK in SYN_RECEIVE
4226 * state is handled above, so we can always just drop the segment and
4227 * send an ACK here.
4228 *
4229 * In the case where the peer shrinks the window, we see the new window
4230 * update, but all the data sent previously is queued up by the peer.
4231 * To account for this, in tcp_process_shrunk_swnd(), the sequence
4232 * number, which was already sent, and within window, is recorded.
4233 * tcp_snxt is then updated.
4234 *
4235 * If the window has previously shrunk, and an ACK for data not yet
4236 * sent, according to tcp_snxt is recieved, it may still be valid. If
4237 * the ACK is for data within the window at the time the window was
4238 * shrunk, then the ACK is acceptable. In this case tcp_snxt is set to
4239 * the sequence number ACK'ed.
4240 *
4241 * If the ACK covers all the data sent at the time the window was
4242 * shrunk, we can now set tcp_is_wnd_shrnk to B_FALSE.
4243 *
4244 * Should we send ACKs in response to ACK only segments?
4245 */
4246
4247 if (SEQ_GT(seg_ack, tcp->tcp_snxt)) {
4248 if ((tcp->tcp_is_wnd_shrnk) &&
4249 (SEQ_LEQ(seg_ack, tcp->tcp_snxt_shrunk))) {
4250 uint32_t data_acked_ahead_snxt;
4251
4252 data_acked_ahead_snxt = seg_ack - tcp->tcp_snxt;
4253 tcp_update_xmit_tail(tcp, seg_ack);
4254 tcp->tcp_unsent -= data_acked_ahead_snxt;
4255 } else {
4256 TCPS_BUMP_MIB(tcps, tcpInAckUnsent);
4257 /* drop the received segment */
4258 freemsg(mp);
4259
4260 /*
4261 * Send back an ACK. If tcp_drop_ack_unsent_cnt is
4262 * greater than 0, check if the number of such
4263 * bogus ACks is greater than that count. If yes,
4264 * don't send back any ACK. This prevents TCP from
4265 * getting into an ACK storm if somehow an attacker
4266 * successfully spoofs an acceptable segment to our
4267 * peer. If this continues (count > 2 X threshold),
4268 * we should abort this connection.
4269 */
4270 if (tcp_drop_ack_unsent_cnt > 0 &&
4271 ++tcp->tcp_in_ack_unsent >
4272 tcp_drop_ack_unsent_cnt) {
4273 TCP_STAT(tcps, tcp_in_ack_unsent_drop);
4274 if (tcp->tcp_in_ack_unsent > 2 *
4275 tcp_drop_ack_unsent_cnt) {
4276 (void) tcp_clean_death(tcp, EPROTO);
4277 }
4278 return;
4279 }
4280 mp = tcp_ack_mp(tcp);
4281 if (mp != NULL) {
4282 TCPS_BUMP_MIB(tcps, tcpHCOutSegs);
4283 TCPS_BUMP_MIB(tcps, tcpOutAck);
4284 tcp_send_data(tcp, mp);
4285 }
4286 return;
4287 }
4288 } else if (tcp->tcp_is_wnd_shrnk && SEQ_GEQ(seg_ack,
4289 tcp->tcp_snxt_shrunk)) {
4290 tcp->tcp_is_wnd_shrnk = B_FALSE;
4291 }
4292
4293 /*
4294 * TCP gets a new ACK, update the notsack'ed list to delete those
4295 * blocks that are covered by this ACK.
4296 */
4297 if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) {
4298 tcp_notsack_remove(&(tcp->tcp_notsack_list), seg_ack,
4299 &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list));
4300 }
4301
4302 /*
4303 * If we got an ACK after fast retransmit, check to see
4304 * if it is a partial ACK. If it is not and the congestion
4305 * window was inflated to account for the other side's
4306 * cached packets, retract it. If it is, do Hoe's algorithm.
4307 */
4308 if (tcp->tcp_dupack_cnt >= tcps->tcps_dupack_fast_retransmit) {
4309 ASSERT(tcp->tcp_rexmit == B_FALSE);
4310 if (SEQ_GEQ(seg_ack, tcp->tcp_rexmit_max)) {
4311 tcp->tcp_dupack_cnt = 0;
4312
4313 cc_post_recovery(tcp, seg_ack);
4314
4315 tcp->tcp_rexmit_max = seg_ack;
4316
4317 /*
4318 * Remove all notsack info to avoid confusion with
4319 * the next fast retrasnmit/recovery phase.
4320 */
4321 if (tcp->tcp_snd_sack_ok) {
4322 TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list,
4323 tcp);
4324 }
4325 } else {
4326 if (tcp->tcp_snd_sack_ok &&
4327 tcp->tcp_notsack_list != NULL) {
4328 flags |= TH_NEED_SACK_REXMIT;
4329 tcp->tcp_pipe -= mss;
4330 if (tcp->tcp_pipe < 0)
4331 tcp->tcp_pipe = 0;
4332 } else {
4333 /*
4334 * Hoe's algorithm:
4335 *
4336 * Retransmit the unack'ed segment and
4337 * restart fast recovery. Note that we
4338 * need to scale back tcp_cwnd to the
4339 * original value when we started fast
4340 * recovery. This is to prevent overly
4341 * aggressive behaviour in sending new
4342 * segments.
4343 */
4344 cwnd = tcp->tcp_cwnd_ssthresh +
4345 tcps->tcps_dupack_fast_retransmit * mss;
4346 DTRACE_PROBE3(cwnd__fast__retransmit__part__ack,
4347 tcp_t *, tcp, uint32_t, tcp->tcp_cwnd,
4348 uint32_t, cwnd);
4349 tcp->tcp_cwnd = cwnd;
4350 tcp->tcp_cwnd_cnt = tcp->tcp_cwnd;
4351 flags |= TH_REXMIT_NEEDED;
4352 }
4353 }
4354 } else {
4355 tcp->tcp_dupack_cnt = 0;
4356 if (tcp->tcp_rexmit) {
4357 /*
4358 * TCP is retranmitting. If the ACK ack's all
4359 * outstanding data, update tcp_rexmit_max and
4360 * tcp_rexmit_nxt. Otherwise, update tcp_rexmit_nxt
4361 * to the correct value.
4362 *
4363 * Note that SEQ_LEQ() is used. This is to avoid
4364 * unnecessary fast retransmit caused by dup ACKs
4365 * received when TCP does slow start retransmission
4366 * after a time out. During this phase, TCP may
4367 * send out segments which are already received.
4368 * This causes dup ACKs to be sent back.
4369 */
4370 if (SEQ_LEQ(seg_ack, tcp->tcp_rexmit_max)) {
4371 if (SEQ_GT(seg_ack, tcp->tcp_rexmit_nxt)) {
4372 tcp->tcp_rexmit_nxt = seg_ack;
4373 }
4374 if (seg_ack != tcp->tcp_rexmit_max) {
4375 flags |= TH_XMIT_NEEDED;
4376 }
4377 } else {
4378 tcp->tcp_rexmit = B_FALSE;
4379 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
4380 }
4381 tcp->tcp_ms_we_have_waited = 0;
4382 }
4383 }
4384
4385 TCPS_BUMP_MIB(tcps, tcpInAckSegs);
4386 TCPS_UPDATE_MIB(tcps, tcpInAckBytes, bytes_acked);
4387 tcp->tcp_suna = seg_ack;
4388 if (tcp->tcp_zero_win_probe != 0) {
4389 tcp->tcp_zero_win_probe = 0;
4390 tcp->tcp_timer_backoff = 0;
4391 }
4392
4393 /*
4394 * If tcp_xmit_head is NULL, then it must be the FIN being ack'ed.
4395 * Note that it cannot be the SYN being ack'ed. The code flow
4396 * will not reach here.
4397 */
4398 if (mp1 == NULL) {
4399 goto fin_acked;
4400 }
4401
4402 /*
4403 * Update the congestion window.
4404 *
4405 * If TCP is not ECN capable or TCP is ECN capable but the
4406 * congestion experience bit is not set, increase the tcp_cwnd as
4407 * usual.
4408 */
4409 if (!tcp->tcp_ecn_ok || !(flags & TH_ECE)) {
4410 if (IN_RECOVERY(tcp->tcp_ccv.flags)) {
4411 EXIT_RECOVERY(tcp->tcp_ccv.flags);
4412 }
4413 cc_ack_received(tcp, seg_ack, bytes_acked, CC_ACK);
4414 }
4415
4416 /* See if the latest urgent data has been acknowledged */
4417 if ((tcp->tcp_valid_bits & TCP_URG_VALID) &&
4418 SEQ_GT(seg_ack, tcp->tcp_urg))
4419 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
4420
4421 /*
4422 * Update the RTT estimates. Note that we don't use the TCP
4423 * timestamp option to calculate RTT even if one is present. This is
4424 * because the timestamp option's resolution (CPU tick) is
4425 * too coarse to measure modern datacenter networks' microsecond
4426 * latencies. The timestamp field's resolution is limited by its
4427 * 4-byte width (see RFC1323), and since we always store a
4428 * high-resolution nanosecond presision timestamp along with the data,
4429 * there is no point to ever using the timestamp option.
4430 */
4431 if (SEQ_GT(seg_ack, tcp->tcp_csuna)) {
4432 /*
4433 * An ACK sequence we haven't seen before, so get the RTT
4434 * and update the RTO. But first check if the timestamp is
4435 * valid to use.
4436 */
4437 if ((mp1->b_next != NULL) &&
4438 SEQ_GT(seg_ack, (uint32_t)(uintptr_t)(mp1->b_next))) {
4439 tcp_set_rto(tcp, gethrtime() -
4440 (hrtime_t)(intptr_t)mp1->b_prev);
4441 } else {
4442 TCPS_BUMP_MIB(tcps, tcpRttNoUpdate);
4443 }
4444
4445 /* Remeber the last sequence to be ACKed */
4446 tcp->tcp_csuna = seg_ack;
4447 if (tcp->tcp_set_timer == 1) {
4448 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
4449 tcp->tcp_set_timer = 0;
4450 }
4451 } else {
4452 TCPS_BUMP_MIB(tcps, tcpRttNoUpdate);
4453 }
4454
4455 /* Eat acknowledged bytes off the xmit queue. */
4456 for (;;) {
4457 mblk_t *mp2;
4458 uchar_t *wptr;
4459
4460 wptr = mp1->b_wptr;
4461 ASSERT((uintptr_t)(wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX);
4462 bytes_acked -= (int)(wptr - mp1->b_rptr);
4463 if (bytes_acked < 0) {
4464 mp1->b_rptr = wptr + bytes_acked;
4465 /*
4466 * Set a new timestamp if all the bytes timed by the
4467 * old timestamp have been ack'ed.
4468 */
4469 if (SEQ_GT(seg_ack,
4470 (uint32_t)(uintptr_t)(mp1->b_next))) {
4471 mp1->b_prev =
4472 (mblk_t *)(intptr_t)gethrtime();
4473 mp1->b_next = NULL;
4474 }
4475 break;
4476 }
4477 mp1->b_next = NULL;
4478 mp1->b_prev = NULL;
4479 mp2 = mp1;
4480 mp1 = mp1->b_cont;
4481
4482 /*
4483 * This notification is required for some zero-copy
4484 * clients to maintain a copy semantic. After the data
4485 * is ack'ed, client is safe to modify or reuse the buffer.
4486 */
4487 if (tcp->tcp_snd_zcopy_aware &&
4488 (mp2->b_datap->db_struioflag & STRUIO_ZCNOTIFY))
4489 tcp_zcopy_notify(tcp);
4490 freeb(mp2);
4491 if (bytes_acked == 0) {
4492 if (mp1 == NULL) {
4493 /* Everything is ack'ed, clear the tail. */
4494 tcp->tcp_xmit_tail = NULL;
4495 /*
4496 * Cancel the timer unless we are still
4497 * waiting for an ACK for the FIN packet.
4498 */
4499 if (tcp->tcp_timer_tid != 0 &&
4500 tcp->tcp_snxt == tcp->tcp_suna) {
4501 (void) TCP_TIMER_CANCEL(tcp,
4502 tcp->tcp_timer_tid);
4503 tcp->tcp_timer_tid = 0;
4504 }
4505 goto pre_swnd_update;
4506 }
4507 if (mp2 != tcp->tcp_xmit_tail)
4508 break;
4509 tcp->tcp_xmit_tail = mp1;
4510 ASSERT((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <=
4511 (uintptr_t)INT_MAX);
4512 tcp->tcp_xmit_tail_unsent = (int)(mp1->b_wptr -
4513 mp1->b_rptr);
4514 break;
4515 }
4516 if (mp1 == NULL) {
4517 /*
4518 * More was acked but there is nothing more
4519 * outstanding. This means that the FIN was
4520 * just acked or that we're talking to a clown.
4521 */
4522 fin_acked:
4523 ASSERT(tcp->tcp_fin_sent);
4524 tcp->tcp_xmit_tail = NULL;
4525 if (tcp->tcp_fin_sent) {
4526 /* FIN was acked - making progress */
4527 if (!tcp->tcp_fin_acked)
4528 tcp->tcp_ip_forward_progress = B_TRUE;
4529 tcp->tcp_fin_acked = B_TRUE;
4530 if (tcp->tcp_linger_tid != 0 &&
4531 TCP_TIMER_CANCEL(tcp,
4532 tcp->tcp_linger_tid) >= 0) {
4533 tcp_stop_lingering(tcp);
4534 freemsg(mp);
4535 mp = NULL;
4536 }
4537 } else {
4538 /*
4539 * We should never get here because
4540 * we have already checked that the
4541 * number of bytes ack'ed should be
4542 * smaller than or equal to what we
4543 * have sent so far (it is the
4544 * acceptability check of the ACK).
4545 * We can only get here if the send
4546 * queue is corrupted.
4547 *
4548 * Terminate the connection and
4549 * panic the system. It is better
4550 * for us to panic instead of
4551 * continuing to avoid other disaster.
4552 */
4553 tcp_xmit_ctl(NULL, tcp, tcp->tcp_snxt,
4554 tcp->tcp_rnxt, TH_RST|TH_ACK);
4555 panic("Memory corruption "
4556 "detected for connection %s.",
4557 tcp_display(tcp, NULL,
4558 DISP_ADDR_AND_PORT));
4559 /*NOTREACHED*/
4560 }
4561 goto pre_swnd_update;
4562 }
4563 ASSERT(mp2 != tcp->tcp_xmit_tail);
4564 }
4565 if (tcp->tcp_unsent) {
4566 flags |= TH_XMIT_NEEDED;
4567 }
4568 pre_swnd_update:
4569 tcp->tcp_xmit_head = mp1;
4570 swnd_update:
4571 /*
4572 * The following check is different from most other implementations.
4573 * For bi-directional transfer, when segments are dropped, the
4574 * "normal" check will not accept a window update in those
4575 * retransmitted segemnts. Failing to do that, TCP may send out
4576 * segments which are outside receiver's window. As TCP accepts
4577 * the ack in those retransmitted segments, if the window update in
4578 * the same segment is not accepted, TCP will incorrectly calculates
4579 * that it can send more segments. This can create a deadlock
4580 * with the receiver if its window becomes zero.
4581 */
4582 if (SEQ_LT(tcp->tcp_swl2, seg_ack) ||
4583 SEQ_LT(tcp->tcp_swl1, seg_seq) ||
4584 (tcp->tcp_swl1 == seg_seq && new_swnd > tcp->tcp_swnd)) {
4585 /*
4586 * The criteria for update is:
4587 *
4588 * 1. the segment acknowledges some data. Or
4589 * 2. the segment is new, i.e. it has a higher seq num. Or
4590 * 3. the segment is not old and the advertised window is
4591 * larger than the previous advertised window.
4592 */
4593 if (tcp->tcp_unsent && new_swnd > tcp->tcp_swnd)
4594 flags |= TH_XMIT_NEEDED;
4595 tcp->tcp_swnd = new_swnd;
4596 if (new_swnd > tcp->tcp_max_swnd)
4597 tcp->tcp_max_swnd = new_swnd;
4598 tcp->tcp_swl1 = seg_seq;
4599 tcp->tcp_swl2 = seg_ack;
4600 }
4601 est:
4602 if (tcp->tcp_state > TCPS_ESTABLISHED) {
4603
4604 switch (tcp->tcp_state) {
4605 case TCPS_FIN_WAIT_1:
4606 if (tcp->tcp_fin_acked) {
4607 tcp->tcp_state = TCPS_FIN_WAIT_2;
4608 DTRACE_TCP6(state__change, void, NULL,
4609 ip_xmit_attr_t *, connp->conn_ixa,
4610 void, NULL, tcp_t *, tcp, void, NULL,
4611 int32_t, TCPS_FIN_WAIT_1);
4612 /*
4613 * We implement the non-standard BSD/SunOS
4614 * FIN_WAIT_2 flushing algorithm.
4615 * If there is no user attached to this
4616 * TCP endpoint, then this TCP struct
4617 * could hang around forever in FIN_WAIT_2
4618 * state if the peer forgets to send us
4619 * a FIN. To prevent this, we wait only
4620 * 2*MSL (a convenient time value) for
4621 * the FIN to arrive. If it doesn't show up,
4622 * we flush the TCP endpoint. This algorithm,
4623 * though a violation of RFC-793, has worked
4624 * for over 10 years in BSD systems.
4625 * Note: SunOS 4.x waits 675 seconds before
4626 * flushing the FIN_WAIT_2 connection.
4627 */
4628 TCP_TIMER_RESTART(tcp,
4629 tcp->tcp_fin_wait_2_flush_interval);
4630 }
4631 break;
4632 case TCPS_FIN_WAIT_2:
4633 break; /* Shutdown hook? */
4634 case TCPS_LAST_ACK:
4635 freemsg(mp);
4636 if (tcp->tcp_fin_acked) {
4637 (void) tcp_clean_death(tcp, 0);
4638 return;
4639 }
4640 goto xmit_check;
4641 case TCPS_CLOSING:
4642 if (tcp->tcp_fin_acked) {
4643 SET_TIME_WAIT(tcps, tcp, connp);
4644 DTRACE_TCP6(state__change, void, NULL,
4645 ip_xmit_attr_t *, connp->conn_ixa, void,
4646 NULL, tcp_t *, tcp, void, NULL, int32_t,
4647 TCPS_CLOSING);
4648 }
4649 /*FALLTHRU*/
4650 case TCPS_CLOSE_WAIT:
4651 freemsg(mp);
4652 goto xmit_check;
4653 default:
4654 ASSERT(tcp->tcp_state != TCPS_TIME_WAIT);
4655 break;
4656 }
4657 }
4658 if (flags & TH_FIN) {
4659 /* Make sure we ack the fin */
4660 flags |= TH_ACK_NEEDED;
4661 if (!tcp->tcp_fin_rcvd) {
4662 tcp->tcp_fin_rcvd = B_TRUE;
4663 tcp->tcp_rnxt++;
4664 tcpha = tcp->tcp_tcpha;
4665 tcpha->tha_ack = htonl(tcp->tcp_rnxt);
4666
4667 /*
4668 * Generate the ordrel_ind at the end unless the
4669 * conn is detached or it is a STREAMS based eager.
4670 * In the eager case we defer the notification until
4671 * tcp_accept_finish has run.
4672 */
4673 if (!TCP_IS_DETACHED(tcp) && (IPCL_IS_NONSTR(connp) ||
4674 (tcp->tcp_listener == NULL &&
4675 !tcp->tcp_hard_binding)))
4676 flags |= TH_ORDREL_NEEDED;
4677 switch (tcp->tcp_state) {
4678 case TCPS_SYN_RCVD:
4679 tcp->tcp_state = TCPS_CLOSE_WAIT;
4680 DTRACE_TCP6(state__change, void, NULL,
4681 ip_xmit_attr_t *, connp->conn_ixa,
4682 void, NULL, tcp_t *, tcp, void, NULL,
4683 int32_t, TCPS_SYN_RCVD);
4684 /* Keepalive? */
4685 break;
4686 case TCPS_ESTABLISHED:
4687 tcp->tcp_state = TCPS_CLOSE_WAIT;
4688 DTRACE_TCP6(state__change, void, NULL,
4689 ip_xmit_attr_t *, connp->conn_ixa,
4690 void, NULL, tcp_t *, tcp, void, NULL,
4691 int32_t, TCPS_ESTABLISHED);
4692 /* Keepalive? */
4693 break;
4694 case TCPS_FIN_WAIT_1:
4695 if (!tcp->tcp_fin_acked) {
4696 tcp->tcp_state = TCPS_CLOSING;
4697 DTRACE_TCP6(state__change, void, NULL,
4698 ip_xmit_attr_t *, connp->conn_ixa,
4699 void, NULL, tcp_t *, tcp, void,
4700 NULL, int32_t, TCPS_FIN_WAIT_1);
4701 break;
4702 }
4703 /* FALLTHRU */
4704 case TCPS_FIN_WAIT_2:
4705 SET_TIME_WAIT(tcps, tcp, connp);
4706 DTRACE_TCP6(state__change, void, NULL,
4707 ip_xmit_attr_t *, connp->conn_ixa, void,
4708 NULL, tcp_t *, tcp, void, NULL, int32_t,
4709 TCPS_FIN_WAIT_2);
4710 if (seg_len) {
4711 /*
4712 * implies data piggybacked on FIN.
4713 * break to handle data.
4714 */
4715 break;
4716 }
4717 freemsg(mp);
4718 goto ack_check;
4719 }
4720 }
4721 }
4722 if (mp == NULL)
4723 goto xmit_check;
4724 if (seg_len == 0) {
4725 freemsg(mp);
4726 goto xmit_check;
4727 }
4728 if (mp->b_rptr == mp->b_wptr) {
4729 /*
4730 * The header has been consumed, so we remove the
4731 * zero-length mblk here.
4732 */
4733 mp1 = mp;
4734 mp = mp->b_cont;
4735 freeb(mp1);
4736 }
4737 update_ack:
4738 tcpha = tcp->tcp_tcpha;
4739 tcp->tcp_rack_cnt++;
4740 {
4741 uint32_t cur_max;
4742
4743 cur_max = tcp->tcp_rack_cur_max;
4744 if (tcp->tcp_rack_cnt >= cur_max) {
4745 /*
4746 * We have more unacked data than we should - send
4747 * an ACK now.
4748 */
4749 flags |= TH_ACK_NEEDED;
4750 cur_max++;
4751 if (cur_max > tcp->tcp_rack_abs_max)
4752 tcp->tcp_rack_cur_max = tcp->tcp_rack_abs_max;
4753 else
4754 tcp->tcp_rack_cur_max = cur_max;
4755 } else if (TCP_IS_DETACHED(tcp)) {
4756 /* We don't have an ACK timer for detached TCP. */
4757 flags |= TH_ACK_NEEDED;
4758 } else if (seg_len < mss) {
4759 /*
4760 * If we get a segment that is less than an mss, and we
4761 * already have unacknowledged data, and the amount
4762 * unacknowledged is not a multiple of mss, then we
4763 * better generate an ACK now. Otherwise, this may be
4764 * the tail piece of a transaction, and we would rather
4765 * wait for the response.
4766 */
4767 uint32_t udif;
4768 ASSERT((uintptr_t)(tcp->tcp_rnxt - tcp->tcp_rack) <=
4769 (uintptr_t)INT_MAX);
4770 udif = (int)(tcp->tcp_rnxt - tcp->tcp_rack);
4771 if (udif && (udif % mss))
4772 flags |= TH_ACK_NEEDED;
4773 else
4774 flags |= TH_ACK_TIMER_NEEDED;
4775 } else {
4776 /* Start delayed ack timer */
4777 flags |= TH_ACK_TIMER_NEEDED;
4778 }
4779 }
4780 tcp->tcp_rnxt += seg_len;
4781 tcpha->tha_ack = htonl(tcp->tcp_rnxt);
4782
4783 if (mp == NULL)
4784 goto xmit_check;
4785
4786 /* Update SACK list */
4787 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
4788 tcp_sack_remove(tcp->tcp_sack_list, tcp->tcp_rnxt,
4789 &(tcp->tcp_num_sack_blk));
4790 }
4791
4792 if (tcp->tcp_urp_mp) {
4793 tcp->tcp_urp_mp->b_cont = mp;
4794 mp = tcp->tcp_urp_mp;
4795 tcp->tcp_urp_mp = NULL;
4796 /* Ready for a new signal. */
4797 tcp->tcp_urp_last_valid = B_FALSE;
4798 #ifdef DEBUG
4799 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
4800 "tcp_rput: sending exdata_ind %s",
4801 tcp_display(tcp, NULL, DISP_PORT_ONLY));
4802 #endif /* DEBUG */
4803 }
4804
4805 /*
4806 * Check for ancillary data changes compared to last segment.
4807 */
4808 if (connp->conn_recv_ancillary.crb_all != 0) {
4809 mp = tcp_input_add_ancillary(tcp, mp, &ipp, ira);
4810 if (mp == NULL)
4811 return;
4812 }
4813
4814 if (IPCL_IS_NONSTR(connp)) {
4815 /*
4816 * Non-STREAMS socket
4817 */
4818 boolean_t push = flags & (TH_PUSH|TH_FIN);
4819 int error;
4820
4821 if ((*sockupcalls->su_recv)(connp->conn_upper_handle,
4822 mp, seg_len, 0, &error, &push) <= 0) {
4823 /*
4824 * We should never be in middle of a
4825 * fallback, the squeue guarantees that.
4826 */
4827 ASSERT(error != EOPNOTSUPP);
4828 if (error == ENOSPC)
4829 tcp->tcp_rwnd -= seg_len;
4830 } else if (push) {
4831 /* PUSH bit set and sockfs is not flow controlled */
4832 flags |= tcp_rwnd_reopen(tcp);
4833 }
4834 } else if (tcp->tcp_listener != NULL || tcp->tcp_hard_binding) {
4835 /*
4836 * Side queue inbound data until the accept happens.
4837 * tcp_accept/tcp_rput drains this when the accept happens.
4838 * M_DATA is queued on b_cont. Otherwise (T_OPTDATA_IND or
4839 * T_EXDATA_IND) it is queued on b_next.
4840 * XXX Make urgent data use this. Requires:
4841 * Removing tcp_listener check for TH_URG
4842 * Making M_PCPROTO and MARK messages skip the eager case
4843 */
4844
4845 tcp_rcv_enqueue(tcp, mp, seg_len, ira->ira_cred);
4846 } else {
4847 /* Active STREAMS socket */
4848 if (mp->b_datap->db_type != M_DATA ||
4849 (flags & TH_MARKNEXT_NEEDED)) {
4850 if (tcp->tcp_rcv_list != NULL) {
4851 flags |= tcp_rcv_drain(tcp);
4852 }
4853 ASSERT(tcp->tcp_rcv_list == NULL ||
4854 tcp->tcp_fused_sigurg);
4855
4856 if (flags & TH_MARKNEXT_NEEDED) {
4857 #ifdef DEBUG
4858 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
4859 "tcp_rput: sending MSGMARKNEXT %s",
4860 tcp_display(tcp, NULL,
4861 DISP_PORT_ONLY));
4862 #endif /* DEBUG */
4863 mp->b_flag |= MSGMARKNEXT;
4864 flags &= ~TH_MARKNEXT_NEEDED;
4865 }
4866
4867 if (is_system_labeled())
4868 tcp_setcred_data(mp, ira);
4869
4870 putnext(connp->conn_rq, mp);
4871 if (!canputnext(connp->conn_rq))
4872 tcp->tcp_rwnd -= seg_len;
4873 } else if ((flags & (TH_PUSH|TH_FIN)) ||
4874 tcp->tcp_rcv_cnt + seg_len >= connp->conn_rcvbuf >> 3) {
4875 if (tcp->tcp_rcv_list != NULL) {
4876 /*
4877 * Enqueue the new segment first and then
4878 * call tcp_rcv_drain() to send all data
4879 * up. The other way to do this is to
4880 * send all queued data up and then call
4881 * putnext() to send the new segment up.
4882 * This way can remove the else part later
4883 * on.
4884 *
4885 * We don't do this to avoid one more call to
4886 * canputnext() as tcp_rcv_drain() needs to
4887 * call canputnext().
4888 */
4889 tcp_rcv_enqueue(tcp, mp, seg_len,
4890 ira->ira_cred);
4891 flags |= tcp_rcv_drain(tcp);
4892 } else {
4893 if (is_system_labeled())
4894 tcp_setcred_data(mp, ira);
4895
4896 putnext(connp->conn_rq, mp);
4897 if (!canputnext(connp->conn_rq))
4898 tcp->tcp_rwnd -= seg_len;
4899 }
4900 } else {
4901 /*
4902 * Enqueue all packets when processing an mblk
4903 * from the co queue and also enqueue normal packets.
4904 */
4905 tcp_rcv_enqueue(tcp, mp, seg_len, ira->ira_cred);
4906 }
4907 /*
4908 * Make sure the timer is running if we have data waiting
4909 * for a push bit. This provides resiliency against
4910 * implementations that do not correctly generate push bits.
4911 */
4912 if (tcp->tcp_rcv_list != NULL && tcp->tcp_push_tid == 0) {
4913 /*
4914 * The connection may be closed at this point, so don't
4915 * do anything for a detached tcp.
4916 */
4917 if (!TCP_IS_DETACHED(tcp))
4918 tcp->tcp_push_tid = TCP_TIMER(tcp,
4919 tcp_push_timer,
4920 tcps->tcps_push_timer_interval);
4921 }
4922 }
4923
4924 xmit_check:
4925 /* Is there anything left to do? */
4926 ASSERT(!(flags & TH_MARKNEXT_NEEDED));
4927 if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_ACK_NEEDED|
4928 TH_NEED_SACK_REXMIT|TH_LIMIT_XMIT|TH_ACK_TIMER_NEEDED|
4929 TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
4930 goto done;
4931
4932 /* Any transmit work to do and a non-zero window? */
4933 if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_NEED_SACK_REXMIT|
4934 TH_LIMIT_XMIT)) && tcp->tcp_swnd != 0) {
4935 if (flags & TH_REXMIT_NEEDED) {
4936 uint32_t snd_size = tcp->tcp_snxt - tcp->tcp_suna;
4937
4938 TCPS_BUMP_MIB(tcps, tcpOutFastRetrans);
4939 if (snd_size > mss)
4940 snd_size = mss;
4941 if (snd_size > tcp->tcp_swnd)
4942 snd_size = tcp->tcp_swnd;
4943 mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, snd_size,
4944 NULL, NULL, tcp->tcp_suna, B_TRUE, &snd_size,
4945 B_TRUE);
4946
4947 if (mp1 != NULL) {
4948 tcp->tcp_xmit_head->b_prev =
4949 (mblk_t *)(intptr_t)gethrtime();
4950 tcp->tcp_csuna = tcp->tcp_snxt;
4951 TCPS_BUMP_MIB(tcps, tcpRetransSegs);
4952 TCPS_UPDATE_MIB(tcps, tcpRetransBytes,
4953 snd_size);
4954 tcp->tcp_cs.tcp_out_retrans_segs++;
4955 tcp->tcp_cs.tcp_out_retrans_bytes += snd_size;
4956 tcp_send_data(tcp, mp1);
4957 }
4958 }
4959 if (flags & TH_NEED_SACK_REXMIT) {
4960 tcp_sack_rexmit(tcp, &flags);
4961 }
4962 /*
4963 * For TH_LIMIT_XMIT, tcp_wput_data() is called to send
4964 * out new segment. Note that tcp_rexmit should not be
4965 * set, otherwise TH_LIMIT_XMIT should not be set.
4966 */
4967 if (flags & (TH_XMIT_NEEDED|TH_LIMIT_XMIT)) {
4968 if (!tcp->tcp_rexmit) {
4969 tcp_wput_data(tcp, NULL, B_FALSE);
4970 } else {
4971 tcp_ss_rexmit(tcp);
4972 }
4973 }
4974 /*
4975 * Adjust tcp_cwnd back to normal value after sending
4976 * new data segments.
4977 */
4978 if (flags & TH_LIMIT_XMIT) {
4979 tcp->tcp_cwnd -= mss << (tcp->tcp_dupack_cnt - 1);
4980 /*
4981 * This will restart the timer. Restarting the
4982 * timer is used to avoid a timeout before the
4983 * limited transmitted segment's ACK gets back.
4984 */
4985 if (tcp->tcp_xmit_head != NULL) {
4986 tcp->tcp_xmit_head->b_prev =
4987 (mblk_t *)(intptr_t)gethrtime();
4988 }
4989 }
4990
4991 /* Anything more to do? */
4992 if ((flags & (TH_ACK_NEEDED|TH_ACK_TIMER_NEEDED|
4993 TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
4994 goto done;
4995 }
4996 ack_check:
4997 if (flags & TH_SEND_URP_MARK) {
4998 ASSERT(tcp->tcp_urp_mark_mp);
4999 ASSERT(!IPCL_IS_NONSTR(connp));
5000 /*
5001 * Send up any queued data and then send the mark message
5002 */
5003 if (tcp->tcp_rcv_list != NULL) {
5004 flags |= tcp_rcv_drain(tcp);
5005
5006 }
5007 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_fused_sigurg);
5008 mp1 = tcp->tcp_urp_mark_mp;
5009 tcp->tcp_urp_mark_mp = NULL;
5010 if (is_system_labeled())
5011 tcp_setcred_data(mp1, ira);
5012
5013 putnext(connp->conn_rq, mp1);
5014 #ifdef DEBUG
5015 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
5016 "tcp_rput: sending zero-length %s %s",
5017 ((mp1->b_flag & MSGMARKNEXT) ? "MSGMARKNEXT" :
5018 "MSGNOTMARKNEXT"),
5019 tcp_display(tcp, NULL, DISP_PORT_ONLY));
5020 #endif /* DEBUG */
5021 flags &= ~TH_SEND_URP_MARK;
5022 }
5023 if (flags & TH_ACK_NEEDED) {
5024 /*
5025 * Time to send an ack for some reason.
5026 */
5027 mp1 = tcp_ack_mp(tcp);
5028
5029 if (mp1 != NULL) {
5030 tcp_send_data(tcp, mp1);
5031 TCPS_BUMP_MIB(tcps, tcpHCOutSegs);
5032 TCPS_BUMP_MIB(tcps, tcpOutAck);
5033 }
5034 if (tcp->tcp_ack_tid != 0) {
5035 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_ack_tid);
5036 tcp->tcp_ack_tid = 0;
5037 }
5038 }
5039 if (flags & TH_ACK_TIMER_NEEDED) {
5040 /*
5041 * Arrange for deferred ACK or push wait timeout.
5042 * Start timer if it is not already running.
5043 */
5044 if (tcp->tcp_ack_tid == 0) {
5045 tcp->tcp_ack_tid = TCP_TIMER(tcp, tcp_ack_timer,
5046 tcp->tcp_localnet ?
5047 tcps->tcps_local_dack_interval :
5048 tcps->tcps_deferred_ack_interval);
5049 }
5050 }
5051 if (flags & TH_ORDREL_NEEDED) {
5052 /*
5053 * Notify upper layer about an orderly release. If this is
5054 * a non-STREAMS socket, then just make an upcall. For STREAMS
5055 * we send up an ordrel_ind, unless this is an eager, in which
5056 * case the ordrel will be sent when tcp_accept_finish runs.
5057 * Note that for non-STREAMS we make an upcall even if it is an
5058 * eager, because we have an upper handle to send it to.
5059 */
5060 ASSERT(IPCL_IS_NONSTR(connp) || tcp->tcp_listener == NULL);
5061 ASSERT(!tcp->tcp_detached);
5062
5063 if (IPCL_IS_NONSTR(connp)) {
5064 ASSERT(tcp->tcp_ordrel_mp == NULL);
5065 tcp->tcp_ordrel_done = B_TRUE;
5066 (*sockupcalls->su_opctl)(connp->conn_upper_handle,
5067 SOCK_OPCTL_SHUT_RECV, 0);
5068 goto done;
5069 }
5070
5071 if (tcp->tcp_rcv_list != NULL) {
5072 /*
5073 * Push any mblk(s) enqueued from co processing.
5074 */
5075 flags |= tcp_rcv_drain(tcp);
5076 }
5077 ASSERT(tcp->tcp_rcv_list == NULL || tcp->tcp_fused_sigurg);
5078
5079 mp1 = tcp->tcp_ordrel_mp;
5080 tcp->tcp_ordrel_mp = NULL;
5081 tcp->tcp_ordrel_done = B_TRUE;
5082 putnext(connp->conn_rq, mp1);
5083 }
5084 done:
5085 ASSERT(!(flags & TH_MARKNEXT_NEEDED));
5086 }
5087
5088 /*
5089 * Attach ancillary data to a received TCP segments for the
5090 * ancillary pieces requested by the application that are
5091 * different than they were in the previous data segment.
5092 *
5093 * Save the "current" values once memory allocation is ok so that
5094 * when memory allocation fails we can just wait for the next data segment.
5095 */
5096 static mblk_t *
5097 tcp_input_add_ancillary(tcp_t *tcp, mblk_t *mp, ip_pkt_t *ipp,
5098 ip_recv_attr_t *ira)
5099 {
5100 struct T_optdata_ind *todi;
5101 int optlen;
5102 uchar_t *optptr;
5103 struct T_opthdr *toh;
5104 crb_t addflag; /* Which pieces to add */
5105 mblk_t *mp1;
5106 conn_t *connp = tcp->tcp_connp;
5107
5108 optlen = 0;
5109 addflag.crb_all = 0;
5110 /* If app asked for pktinfo and the index has changed ... */
5111 if (connp->conn_recv_ancillary.crb_ip_recvpktinfo &&
5112 ira->ira_ruifindex != tcp->tcp_recvifindex) {
5113 optlen += sizeof (struct T_opthdr) +
5114 sizeof (struct in6_pktinfo);
5115 addflag.crb_ip_recvpktinfo = 1;
5116 }
5117 /* If app asked for hoplimit and it has changed ... */
5118 if (connp->conn_recv_ancillary.crb_ipv6_recvhoplimit &&
5119 ipp->ipp_hoplimit != tcp->tcp_recvhops) {
5120 optlen += sizeof (struct T_opthdr) + sizeof (uint_t);
5121 addflag.crb_ipv6_recvhoplimit = 1;
5122 }
5123 /* If app asked for tclass and it has changed ... */
5124 if (connp->conn_recv_ancillary.crb_ipv6_recvtclass &&
5125 ipp->ipp_tclass != tcp->tcp_recvtclass) {
5126 optlen += sizeof (struct T_opthdr) + sizeof (uint_t);
5127 addflag.crb_ipv6_recvtclass = 1;
5128 }
5129 /*
5130 * If app asked for hopbyhop headers and it has changed ...
5131 * For security labels, note that (1) security labels can't change on
5132 * a connected socket at all, (2) we're connected to at most one peer,
5133 * (3) if anything changes, then it must be some other extra option.
5134 */
5135 if (connp->conn_recv_ancillary.crb_ipv6_recvhopopts &&
5136 ip_cmpbuf(tcp->tcp_hopopts, tcp->tcp_hopoptslen,
5137 (ipp->ipp_fields & IPPF_HOPOPTS),
5138 ipp->ipp_hopopts, ipp->ipp_hopoptslen)) {
5139 optlen += sizeof (struct T_opthdr) + ipp->ipp_hopoptslen;
5140 addflag.crb_ipv6_recvhopopts = 1;
5141 if (!ip_allocbuf((void **)&tcp->tcp_hopopts,
5142 &tcp->tcp_hopoptslen, (ipp->ipp_fields & IPPF_HOPOPTS),
5143 ipp->ipp_hopopts, ipp->ipp_hopoptslen))
5144 return (mp);
5145 }
5146 /* If app asked for dst headers before routing headers ... */
5147 if (connp->conn_recv_ancillary.crb_ipv6_recvrthdrdstopts &&
5148 ip_cmpbuf(tcp->tcp_rthdrdstopts, tcp->tcp_rthdrdstoptslen,
5149 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5150 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen)) {
5151 optlen += sizeof (struct T_opthdr) +
5152 ipp->ipp_rthdrdstoptslen;
5153 addflag.crb_ipv6_recvrthdrdstopts = 1;
5154 if (!ip_allocbuf((void **)&tcp->tcp_rthdrdstopts,
5155 &tcp->tcp_rthdrdstoptslen,
5156 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5157 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen))
5158 return (mp);
5159 }
5160 /* If app asked for routing headers and it has changed ... */
5161 if (connp->conn_recv_ancillary.crb_ipv6_recvrthdr &&
5162 ip_cmpbuf(tcp->tcp_rthdr, tcp->tcp_rthdrlen,
5163 (ipp->ipp_fields & IPPF_RTHDR),
5164 ipp->ipp_rthdr, ipp->ipp_rthdrlen)) {
5165 optlen += sizeof (struct T_opthdr) + ipp->ipp_rthdrlen;
5166 addflag.crb_ipv6_recvrthdr = 1;
5167 if (!ip_allocbuf((void **)&tcp->tcp_rthdr,
5168 &tcp->tcp_rthdrlen, (ipp->ipp_fields & IPPF_RTHDR),
5169 ipp->ipp_rthdr, ipp->ipp_rthdrlen))
5170 return (mp);
5171 }
5172 /* If app asked for dest headers and it has changed ... */
5173 if ((connp->conn_recv_ancillary.crb_ipv6_recvdstopts ||
5174 connp->conn_recv_ancillary.crb_old_ipv6_recvdstopts) &&
5175 ip_cmpbuf(tcp->tcp_dstopts, tcp->tcp_dstoptslen,
5176 (ipp->ipp_fields & IPPF_DSTOPTS),
5177 ipp->ipp_dstopts, ipp->ipp_dstoptslen)) {
5178 optlen += sizeof (struct T_opthdr) + ipp->ipp_dstoptslen;
5179 addflag.crb_ipv6_recvdstopts = 1;
5180 if (!ip_allocbuf((void **)&tcp->tcp_dstopts,
5181 &tcp->tcp_dstoptslen, (ipp->ipp_fields & IPPF_DSTOPTS),
5182 ipp->ipp_dstopts, ipp->ipp_dstoptslen))
5183 return (mp);
5184 }
5185
5186 if (optlen == 0) {
5187 /* Nothing to add */
5188 return (mp);
5189 }
5190 mp1 = allocb(sizeof (struct T_optdata_ind) + optlen, BPRI_MED);
5191 if (mp1 == NULL) {
5192 /*
5193 * Defer sending ancillary data until the next TCP segment
5194 * arrives.
5195 */
5196 return (mp);
5197 }
5198 mp1->b_cont = mp;
5199 mp = mp1;
5200 mp->b_wptr += sizeof (*todi) + optlen;
5201 mp->b_datap->db_type = M_PROTO;
5202 todi = (struct T_optdata_ind *)mp->b_rptr;
5203 todi->PRIM_type = T_OPTDATA_IND;
5204 todi->DATA_flag = 1; /* MORE data */
5205 todi->OPT_length = optlen;
5206 todi->OPT_offset = sizeof (*todi);
5207 optptr = (uchar_t *)&todi[1];
5208 /*
5209 * If app asked for pktinfo and the index has changed ...
5210 * Note that the local address never changes for the connection.
5211 */
5212 if (addflag.crb_ip_recvpktinfo) {
5213 struct in6_pktinfo *pkti;
5214 uint_t ifindex;
5215
5216 ifindex = ira->ira_ruifindex;
5217 toh = (struct T_opthdr *)optptr;
5218 toh->level = IPPROTO_IPV6;
5219 toh->name = IPV6_PKTINFO;
5220 toh->len = sizeof (*toh) + sizeof (*pkti);
5221 toh->status = 0;
5222 optptr += sizeof (*toh);
5223 pkti = (struct in6_pktinfo *)optptr;
5224 pkti->ipi6_addr = connp->conn_laddr_v6;
5225 pkti->ipi6_ifindex = ifindex;
5226 optptr += sizeof (*pkti);
5227 ASSERT(OK_32PTR(optptr));
5228 /* Save as "last" value */
5229 tcp->tcp_recvifindex = ifindex;
5230 }
5231 /* If app asked for hoplimit and it has changed ... */
5232 if (addflag.crb_ipv6_recvhoplimit) {
5233 toh = (struct T_opthdr *)optptr;
5234 toh->level = IPPROTO_IPV6;
5235 toh->name = IPV6_HOPLIMIT;
5236 toh->len = sizeof (*toh) + sizeof (uint_t);
5237 toh->status = 0;
5238 optptr += sizeof (*toh);
5239 *(uint_t *)optptr = ipp->ipp_hoplimit;
5240 optptr += sizeof (uint_t);
5241 ASSERT(OK_32PTR(optptr));
5242 /* Save as "last" value */
5243 tcp->tcp_recvhops = ipp->ipp_hoplimit;
5244 }
5245 /* If app asked for tclass and it has changed ... */
5246 if (addflag.crb_ipv6_recvtclass) {
5247 toh = (struct T_opthdr *)optptr;
5248 toh->level = IPPROTO_IPV6;
5249 toh->name = IPV6_TCLASS;
5250 toh->len = sizeof (*toh) + sizeof (uint_t);
5251 toh->status = 0;
5252 optptr += sizeof (*toh);
5253 *(uint_t *)optptr = ipp->ipp_tclass;
5254 optptr += sizeof (uint_t);
5255 ASSERT(OK_32PTR(optptr));
5256 /* Save as "last" value */
5257 tcp->tcp_recvtclass = ipp->ipp_tclass;
5258 }
5259 if (addflag.crb_ipv6_recvhopopts) {
5260 toh = (struct T_opthdr *)optptr;
5261 toh->level = IPPROTO_IPV6;
5262 toh->name = IPV6_HOPOPTS;
5263 toh->len = sizeof (*toh) + ipp->ipp_hopoptslen;
5264 toh->status = 0;
5265 optptr += sizeof (*toh);
5266 bcopy((uchar_t *)ipp->ipp_hopopts, optptr, ipp->ipp_hopoptslen);
5267 optptr += ipp->ipp_hopoptslen;
5268 ASSERT(OK_32PTR(optptr));
5269 /* Save as last value */
5270 ip_savebuf((void **)&tcp->tcp_hopopts, &tcp->tcp_hopoptslen,
5271 (ipp->ipp_fields & IPPF_HOPOPTS),
5272 ipp->ipp_hopopts, ipp->ipp_hopoptslen);
5273 }
5274 if (addflag.crb_ipv6_recvrthdrdstopts) {
5275 toh = (struct T_opthdr *)optptr;
5276 toh->level = IPPROTO_IPV6;
5277 toh->name = IPV6_RTHDRDSTOPTS;
5278 toh->len = sizeof (*toh) + ipp->ipp_rthdrdstoptslen;
5279 toh->status = 0;
5280 optptr += sizeof (*toh);
5281 bcopy(ipp->ipp_rthdrdstopts, optptr, ipp->ipp_rthdrdstoptslen);
5282 optptr += ipp->ipp_rthdrdstoptslen;
5283 ASSERT(OK_32PTR(optptr));
5284 /* Save as last value */
5285 ip_savebuf((void **)&tcp->tcp_rthdrdstopts,
5286 &tcp->tcp_rthdrdstoptslen,
5287 (ipp->ipp_fields & IPPF_RTHDRDSTOPTS),
5288 ipp->ipp_rthdrdstopts, ipp->ipp_rthdrdstoptslen);
5289 }
5290 if (addflag.crb_ipv6_recvrthdr) {
5291 toh = (struct T_opthdr *)optptr;
5292 toh->level = IPPROTO_IPV6;
5293 toh->name = IPV6_RTHDR;
5294 toh->len = sizeof (*toh) + ipp->ipp_rthdrlen;
5295 toh->status = 0;
5296 optptr += sizeof (*toh);
5297 bcopy(ipp->ipp_rthdr, optptr, ipp->ipp_rthdrlen);
5298 optptr += ipp->ipp_rthdrlen;
5299 ASSERT(OK_32PTR(optptr));
5300 /* Save as last value */
5301 ip_savebuf((void **)&tcp->tcp_rthdr, &tcp->tcp_rthdrlen,
5302 (ipp->ipp_fields & IPPF_RTHDR),
5303 ipp->ipp_rthdr, ipp->ipp_rthdrlen);
5304 }
5305 if (addflag.crb_ipv6_recvdstopts) {
5306 toh = (struct T_opthdr *)optptr;
5307 toh->level = IPPROTO_IPV6;
5308 toh->name = IPV6_DSTOPTS;
5309 toh->len = sizeof (*toh) + ipp->ipp_dstoptslen;
5310 toh->status = 0;
5311 optptr += sizeof (*toh);
5312 bcopy(ipp->ipp_dstopts, optptr, ipp->ipp_dstoptslen);
5313 optptr += ipp->ipp_dstoptslen;
5314 ASSERT(OK_32PTR(optptr));
5315 /* Save as last value */
5316 ip_savebuf((void **)&tcp->tcp_dstopts, &tcp->tcp_dstoptslen,
5317 (ipp->ipp_fields & IPPF_DSTOPTS),
5318 ipp->ipp_dstopts, ipp->ipp_dstoptslen);
5319 }
5320 ASSERT(optptr == mp->b_wptr);
5321 return (mp);
5322 }
5323
5324 /* The minimum of smoothed mean deviation in RTO calculation (nsec). */
5325 #define TCP_SD_MIN 400000000
5326
5327 /*
5328 * Set RTO for this connection based on a new round-trip time measurement.
5329 * The formula is from Jacobson and Karels' "Congestion Avoidance and Control"
5330 * in SIGCOMM '88. The variable names are the same as those in Appendix A.2
5331 * of that paper.
5332 *
5333 * m = new measurement
5334 * sa = smoothed RTT average (8 * average estimates).
5335 * sv = smoothed mean deviation (mdev) of RTT (4 * deviation estimates).
5336 */
5337 static void
5338 tcp_set_rto(tcp_t *tcp, hrtime_t rtt)
5339 {
5340 hrtime_t m = rtt;
5341 hrtime_t sa = tcp->tcp_rtt_sa;
5342 hrtime_t sv = tcp->tcp_rtt_sd;
5343 tcp_stack_t *tcps = tcp->tcp_tcps;
5344
5345 TCPS_BUMP_MIB(tcps, tcpRttUpdate);
5346 tcp->tcp_rtt_update++;
5347 tcp->tcp_rtt_sum += m;
5348 tcp->tcp_rtt_cnt++;
5349
5350 /* tcp_rtt_sa is not 0 means this is a new sample. */
5351 if (sa != 0) {
5352 /*
5353 * Update average estimator (see section 2.3 of RFC6298):
5354 * SRTT = 7/8 SRTT + 1/8 rtt
5355 *
5356 * We maintain tcp_rtt_sa as 8 * SRTT, so this reduces to:
5357 * tcp_rtt_sa = 7 * SRTT + rtt
5358 * tcp_rtt_sa = 7 * (tcp_rtt_sa / 8) + rtt
5359 * tcp_rtt_sa = tcp_rtt_sa - (tcp_rtt_sa / 8) + rtt
5360 * tcp_rtt_sa = tcp_rtt_sa + (rtt - (tcp_rtt_sa / 8))
5361 * tcp_rtt_sa = tcp_rtt_sa + (rtt - (tcp_rtt_sa / 2^3))
5362 * tcp_rtt_sa = tcp_rtt_sa + (rtt - (tcp_rtt_sa >> 3))
5363 *
5364 * (rtt - tcp_rtt_sa / 8) is simply the difference
5365 * between the new rtt measurement and the existing smoothed
5366 * RTT average. This is referred to as "Error" in subsequent
5367 * calculations.
5368 */
5369
5370 /* m is now Error. */
5371 m -= sa >> 3;
5372 if ((sa += m) <= 0) {
5373 /*
5374 * Don't allow the smoothed average to be negative.
5375 * We use 0 to denote reinitialization of the
5376 * variables.
5377 */
5378 sa = 1;
5379 }
5380
5381 /*
5382 * Update deviation estimator:
5383 * mdev = 3/4 mdev + 1/4 abs(Error)
5384 *
5385 * We maintain tcp_rtt_sd as 4 * mdev, so this reduces to:
5386 * tcp_rtt_sd = 3 * mdev + abs(Error)
5387 * tcp_rtt_sd = tcp_rtt_sd - (tcp_rtt_sd / 4) + abs(Error)
5388 * tcp_rtt_sd = tcp_rtt_sd - (tcp_rtt_sd / 2^2) + abs(Error)
5389 * tcp_rtt_sd = tcp_rtt_sd - (tcp_rtt_sd >> 2) + abs(Error)
5390 */
5391 if (m < 0)
5392 m = -m;
5393 m -= sv >> 2;
5394 sv += m;
5395 } else {
5396 /*
5397 * This follows BSD's implementation. So the reinitialized
5398 * RTO is 3 * m. We cannot go less than 2 because if the
5399 * link is bandwidth dominated, doubling the window size
5400 * during slow start means doubling the RTT. We want to be
5401 * more conservative when we reinitialize our estimates. 3
5402 * is just a convenient number.
5403 */
5404 sa = m << 3;
5405 sv = m << 1;
5406 }
5407 if (sv < TCP_SD_MIN) {
5408 /*
5409 * Since a receiver doesn't delay its ACKs during a long run of
5410 * segments, sa may not have captured the effect of delayed ACK
5411 * timeouts on the RTT. To make sure we always account for the
5412 * possible delay (and avoid the unnecessary retransmission),
5413 * TCP_SD_MIN is set to 400ms, twice the delayed ACK timeout of
5414 * 200ms on older SunOS/BSD systems and modern Windows systems
5415 * (as of 2019). This means that the minimum possible mean
5416 * deviation is 100 ms.
5417 */
5418 sv = TCP_SD_MIN;
5419 }
5420 tcp->tcp_rtt_sa = sa;
5421 tcp->tcp_rtt_sd = sv;
5422
5423 tcp->tcp_rto = tcp_calculate_rto(tcp, tcps, 0);
5424
5425 /* Now, we can reset tcp_timer_backoff to use the new RTO... */
5426 tcp->tcp_timer_backoff = 0;
5427 }
5428
5429 /*
5430 * On a labeled system we have some protocols above TCP, such as RPC, which
5431 * appear to assume that every mblk in a chain has a db_credp.
5432 */
5433 static void
5434 tcp_setcred_data(mblk_t *mp, ip_recv_attr_t *ira)
5435 {
5436 ASSERT(is_system_labeled());
5437 ASSERT(ira->ira_cred != NULL);
5438
5439 while (mp != NULL) {
5440 mblk_setcred(mp, ira->ira_cred, NOPID);
5441 mp = mp->b_cont;
5442 }
5443 }
5444
5445 uint_t
5446 tcp_rwnd_reopen(tcp_t *tcp)
5447 {
5448 uint_t ret = 0;
5449 uint_t thwin;
5450 conn_t *connp = tcp->tcp_connp;
5451
5452 /* Learn the latest rwnd information that we sent to the other side. */
5453 thwin = ((uint_t)ntohs(tcp->tcp_tcpha->tha_win))
5454 << tcp->tcp_rcv_ws;
5455 /* This is peer's calculated send window (our receive window). */
5456 thwin -= tcp->tcp_rnxt - tcp->tcp_rack;
5457 /*
5458 * Increase the receive window to max. But we need to do receiver
5459 * SWS avoidance. This means that we need to check the increase of
5460 * of receive window is at least 1 MSS.
5461 */
5462 if (connp->conn_rcvbuf - thwin >= tcp->tcp_mss) {
5463 /*
5464 * If the window that the other side knows is less than max
5465 * deferred acks segments, send an update immediately.
5466 */
5467 if (thwin < tcp->tcp_rack_cur_max * tcp->tcp_mss) {
5468 TCPS_BUMP_MIB(tcp->tcp_tcps, tcpOutWinUpdate);
5469 ret = TH_ACK_NEEDED;
5470 }
5471 tcp->tcp_rwnd = connp->conn_rcvbuf;
5472 }
5473 return (ret);
5474 }
5475
5476 /*
5477 * Handle a packet that has been reclassified by TCP.
5478 * This function drops the ref on connp that the caller had.
5479 */
5480 void
5481 tcp_reinput(conn_t *connp, mblk_t *mp, ip_recv_attr_t *ira, ip_stack_t *ipst)
5482 {
5483 ipsec_stack_t *ipss = ipst->ips_netstack->netstack_ipsec;
5484
5485 if (connp->conn_incoming_ifindex != 0 &&
5486 connp->conn_incoming_ifindex != ira->ira_ruifindex) {
5487 freemsg(mp);
5488 CONN_DEC_REF(connp);
5489 return;
5490 }
5491
5492 if (CONN_INBOUND_POLICY_PRESENT_V6(connp, ipss) ||
5493 (ira->ira_flags & IRAF_IPSEC_SECURE)) {
5494 ip6_t *ip6h;
5495 ipha_t *ipha;
5496
5497 if (ira->ira_flags & IRAF_IS_IPV4) {
5498 ipha = (ipha_t *)mp->b_rptr;
5499 ip6h = NULL;
5500 } else {
5501 ipha = NULL;
5502 ip6h = (ip6_t *)mp->b_rptr;
5503 }
5504 mp = ipsec_check_inbound_policy(mp, connp, ipha, ip6h, ira);
5505 if (mp == NULL) {
5506 BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsInDiscards);
5507 /* Note that mp is NULL */
5508 ip_drop_input("ipIfStatsInDiscards", mp, NULL);
5509 CONN_DEC_REF(connp);
5510 return;
5511 }
5512 }
5513
5514 if (IPCL_IS_TCP(connp)) {
5515 /*
5516 * do not drain, certain use cases can blow
5517 * the stack
5518 */
5519 SQUEUE_ENTER_ONE(connp->conn_sqp, mp,
5520 connp->conn_recv, connp, ira,
5521 SQ_NODRAIN, SQTAG_IP_TCP_INPUT);
5522 } else {
5523 /* Not TCP; must be SOCK_RAW, IPPROTO_TCP */
5524 (connp->conn_recv)(connp, mp, NULL,
5525 ira);
5526 CONN_DEC_REF(connp);
5527 }
5528
5529 }
5530
5531 /* ARGSUSED */
5532 static void
5533 tcp_rsrv_input(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
5534 {
5535 conn_t *connp = (conn_t *)arg;
5536 tcp_t *tcp = connp->conn_tcp;
5537 queue_t *q = connp->conn_rq;
5538
5539 ASSERT(!IPCL_IS_NONSTR(connp));
5540 mutex_enter(&tcp->tcp_rsrv_mp_lock);
5541 tcp->tcp_rsrv_mp = mp;
5542 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5543
5544 if (TCP_IS_DETACHED(tcp) || q == NULL) {
5545 return;
5546 }
5547
5548 if (tcp->tcp_fused) {
5549 tcp_fuse_backenable(tcp);
5550 return;
5551 }
5552
5553 if (canputnext(q)) {
5554 /* Not flow-controlled, open rwnd */
5555 tcp->tcp_rwnd = connp->conn_rcvbuf;
5556
5557 /*
5558 * Send back a window update immediately if TCP is above
5559 * ESTABLISHED state and the increase of the rcv window
5560 * that the other side knows is at least 1 MSS after flow
5561 * control is lifted.
5562 */
5563 if (tcp->tcp_state >= TCPS_ESTABLISHED &&
5564 tcp_rwnd_reopen(tcp) == TH_ACK_NEEDED) {
5565 tcp_xmit_ctl(NULL, tcp,
5566 (tcp->tcp_swnd == 0) ? tcp->tcp_suna :
5567 tcp->tcp_snxt, tcp->tcp_rnxt, TH_ACK);
5568 }
5569 }
5570 }
5571
5572 /*
5573 * The read side service routine is called mostly when we get back-enabled as a
5574 * result of flow control relief. Since we don't actually queue anything in
5575 * TCP, we have no data to send out of here. What we do is clear the receive
5576 * window, and send out a window update.
5577 */
5578 int
5579 tcp_rsrv(queue_t *q)
5580 {
5581 conn_t *connp = Q_TO_CONN(q);
5582 tcp_t *tcp = connp->conn_tcp;
5583 mblk_t *mp;
5584
5585 /* No code does a putq on the read side */
5586 ASSERT(q->q_first == NULL);
5587
5588 /*
5589 * If tcp->tcp_rsrv_mp == NULL, it means that tcp_rsrv() has already
5590 * been run. So just return.
5591 */
5592 mutex_enter(&tcp->tcp_rsrv_mp_lock);
5593 if ((mp = tcp->tcp_rsrv_mp) == NULL) {
5594 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5595 return (0);
5596 }
5597 tcp->tcp_rsrv_mp = NULL;
5598 mutex_exit(&tcp->tcp_rsrv_mp_lock);
5599
5600 CONN_INC_REF(connp);
5601 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, tcp_rsrv_input, connp,
5602 NULL, SQ_PROCESS, SQTAG_TCP_RSRV);
5603 return (0);
5604 }
5605
5606 /* At minimum we need 8 bytes in the TCP header for the lookup */
5607 #define ICMP_MIN_TCP_HDR 8
5608
5609 /*
5610 * tcp_icmp_input is called as conn_recvicmp to process ICMP error messages
5611 * passed up by IP. The message is always received on the correct tcp_t.
5612 * Assumes that IP has pulled up everything up to and including the ICMP header.
5613 */
5614 /* ARGSUSED2 */
5615 void
5616 tcp_icmp_input(void *arg1, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
5617 {
5618 conn_t *connp = (conn_t *)arg1;
5619 icmph_t *icmph;
5620 ipha_t *ipha;
5621 int iph_hdr_length;
5622 tcpha_t *tcpha;
5623 uint32_t seg_seq;
5624 tcp_t *tcp = connp->conn_tcp;
5625
5626 /* Assume IP provides aligned packets */
5627 ASSERT(OK_32PTR(mp->b_rptr));
5628 ASSERT((MBLKL(mp) >= sizeof (ipha_t)));
5629
5630 /*
5631 * It's possible we have a closed, but not yet destroyed, TCP
5632 * connection. Several fields (e.g. conn_ixa->ixa_ire) are invalid
5633 * in the closed state, so don't take any chances and drop the packet.
5634 */
5635 if (tcp->tcp_state == TCPS_CLOSED) {
5636 freemsg(mp);
5637 return;
5638 }
5639
5640 /*
5641 * Verify IP version. Anything other than IPv4 or IPv6 packet is sent
5642 * upstream. ICMPv6 is handled in tcp_icmp_error_ipv6.
5643 */
5644 if (!(ira->ira_flags & IRAF_IS_IPV4)) {
5645 tcp_icmp_error_ipv6(tcp, mp, ira);
5646 return;
5647 }
5648
5649 /* Skip past the outer IP and ICMP headers */
5650 iph_hdr_length = ira->ira_ip_hdr_length;
5651 icmph = (icmph_t *)&mp->b_rptr[iph_hdr_length];
5652 /*
5653 * If we don't have the correct outer IP header length
5654 * or if we don't have a complete inner IP header
5655 * drop it.
5656 */
5657 if (iph_hdr_length < sizeof (ipha_t) ||
5658 (ipha_t *)&icmph[1] + 1 > (ipha_t *)mp->b_wptr) {
5659 noticmpv4:
5660 freemsg(mp);
5661 return;
5662 }
5663 ipha = (ipha_t *)&icmph[1];
5664
5665 /* Skip past the inner IP and find the ULP header */
5666 iph_hdr_length = IPH_HDR_LENGTH(ipha);
5667 tcpha = (tcpha_t *)((char *)ipha + iph_hdr_length);
5668 /*
5669 * If we don't have the correct inner IP header length or if the ULP
5670 * is not IPPROTO_TCP or if we don't have at least ICMP_MIN_TCP_HDR
5671 * bytes of TCP header, drop it.
5672 */
5673 if (iph_hdr_length < sizeof (ipha_t) ||
5674 ipha->ipha_protocol != IPPROTO_TCP ||
5675 (uchar_t *)tcpha + ICMP_MIN_TCP_HDR > mp->b_wptr) {
5676 goto noticmpv4;
5677 }
5678
5679 seg_seq = ntohl(tcpha->tha_seq);
5680 switch (icmph->icmph_type) {
5681 case ICMP_DEST_UNREACHABLE:
5682 switch (icmph->icmph_code) {
5683 case ICMP_FRAGMENTATION_NEEDED:
5684 /*
5685 * Update Path MTU, then try to send something out.
5686 */
5687 tcp_update_pmtu(tcp, B_TRUE);
5688 tcp_rexmit_after_error(tcp);
5689 break;
5690 case ICMP_PORT_UNREACHABLE:
5691 case ICMP_PROTOCOL_UNREACHABLE:
5692 switch (tcp->tcp_state) {
5693 case TCPS_SYN_SENT:
5694 case TCPS_SYN_RCVD:
5695 /*
5696 * ICMP can snipe away incipient
5697 * TCP connections as long as
5698 * seq number is same as initial
5699 * send seq number.
5700 */
5701 if (seg_seq == tcp->tcp_iss) {
5702 (void) tcp_clean_death(tcp,
5703 ECONNREFUSED);
5704 }
5705 break;
5706 }
5707 break;
5708 case ICMP_HOST_UNREACHABLE:
5709 case ICMP_NET_UNREACHABLE:
5710 /* Record the error in case we finally time out. */
5711 if (icmph->icmph_code == ICMP_HOST_UNREACHABLE)
5712 tcp->tcp_client_errno = EHOSTUNREACH;
5713 else
5714 tcp->tcp_client_errno = ENETUNREACH;
5715 if (tcp->tcp_state == TCPS_SYN_RCVD) {
5716 if (tcp->tcp_listener != NULL &&
5717 tcp->tcp_listener->tcp_syn_defense) {
5718 /*
5719 * Ditch the half-open connection if we
5720 * suspect a SYN attack is under way.
5721 */
5722 (void) tcp_clean_death(tcp,
5723 tcp->tcp_client_errno);
5724 }
5725 }
5726 break;
5727 default:
5728 break;
5729 }
5730 break;
5731 case ICMP_SOURCE_QUENCH: {
5732 /*
5733 * use a global boolean to control
5734 * whether TCP should respond to ICMP_SOURCE_QUENCH.
5735 * The default is false.
5736 */
5737 if (tcp_icmp_source_quench) {
5738 /*
5739 * Reduce the sending rate as if we got a
5740 * retransmit timeout
5741 */
5742 uint32_t npkt;
5743
5744 npkt = ((tcp->tcp_snxt - tcp->tcp_suna) >> 1) /
5745 tcp->tcp_mss;
5746 tcp->tcp_cwnd_ssthresh = MAX(npkt, 2) * tcp->tcp_mss;
5747
5748 DTRACE_PROBE3(cwnd__source__quench, tcp_t *, tcp,
5749 uint32_t, tcp->tcp_cwnd,
5750 uint32_t, tcp->tcp_mss);
5751 tcp->tcp_cwnd = tcp->tcp_mss;
5752 tcp->tcp_cwnd_cnt = 0;
5753 }
5754 break;
5755 }
5756 }
5757 freemsg(mp);
5758 }
5759
5760 /*
5761 * tcp_icmp_error_ipv6 is called from tcp_icmp_input to process ICMPv6
5762 * error messages passed up by IP.
5763 * Assumes that IP has pulled up all the extension headers as well
5764 * as the ICMPv6 header.
5765 */
5766 static void
5767 tcp_icmp_error_ipv6(tcp_t *tcp, mblk_t *mp, ip_recv_attr_t *ira)
5768 {
5769 icmp6_t *icmp6;
5770 ip6_t *ip6h;
5771 uint16_t iph_hdr_length = ira->ira_ip_hdr_length;
5772 tcpha_t *tcpha;
5773 uint8_t *nexthdrp;
5774 uint32_t seg_seq;
5775
5776 /*
5777 * Verify that we have a complete IP header.
5778 */
5779 ASSERT((MBLKL(mp) >= sizeof (ip6_t)));
5780
5781 icmp6 = (icmp6_t *)&mp->b_rptr[iph_hdr_length];
5782 ip6h = (ip6_t *)&icmp6[1];
5783 /*
5784 * Verify if we have a complete ICMP and inner IP header.
5785 */
5786 if ((uchar_t *)&ip6h[1] > mp->b_wptr) {
5787 noticmpv6:
5788 freemsg(mp);
5789 return;
5790 }
5791
5792 if (!ip_hdr_length_nexthdr_v6(mp, ip6h, &iph_hdr_length, &nexthdrp))
5793 goto noticmpv6;
5794 tcpha = (tcpha_t *)((char *)ip6h + iph_hdr_length);
5795 /*
5796 * Validate inner header. If the ULP is not IPPROTO_TCP or if we don't
5797 * have at least ICMP_MIN_TCP_HDR bytes of TCP header drop the
5798 * packet.
5799 */
5800 if ((*nexthdrp != IPPROTO_TCP) ||
5801 ((uchar_t *)tcpha + ICMP_MIN_TCP_HDR) > mp->b_wptr) {
5802 goto noticmpv6;
5803 }
5804
5805 seg_seq = ntohl(tcpha->tha_seq);
5806 switch (icmp6->icmp6_type) {
5807 case ICMP6_PACKET_TOO_BIG:
5808 /*
5809 * Update Path MTU, then try to send something out.
5810 */
5811 tcp_update_pmtu(tcp, B_TRUE);
5812 tcp_rexmit_after_error(tcp);
5813 break;
5814 case ICMP6_DST_UNREACH:
5815 switch (icmp6->icmp6_code) {
5816 case ICMP6_DST_UNREACH_NOPORT:
5817 if (((tcp->tcp_state == TCPS_SYN_SENT) ||
5818 (tcp->tcp_state == TCPS_SYN_RCVD)) &&
5819 (seg_seq == tcp->tcp_iss)) {
5820 (void) tcp_clean_death(tcp, ECONNREFUSED);
5821 }
5822 break;
5823 case ICMP6_DST_UNREACH_ADMIN:
5824 case ICMP6_DST_UNREACH_NOROUTE:
5825 case ICMP6_DST_UNREACH_BEYONDSCOPE:
5826 case ICMP6_DST_UNREACH_ADDR:
5827 /* Record the error in case we finally time out. */
5828 tcp->tcp_client_errno = EHOSTUNREACH;
5829 if (((tcp->tcp_state == TCPS_SYN_SENT) ||
5830 (tcp->tcp_state == TCPS_SYN_RCVD)) &&
5831 (seg_seq == tcp->tcp_iss)) {
5832 if (tcp->tcp_listener != NULL &&
5833 tcp->tcp_listener->tcp_syn_defense) {
5834 /*
5835 * Ditch the half-open connection if we
5836 * suspect a SYN attack is under way.
5837 */
5838 (void) tcp_clean_death(tcp,
5839 tcp->tcp_client_errno);
5840 }
5841 }
5842
5843
5844 break;
5845 default:
5846 break;
5847 }
5848 break;
5849 case ICMP6_PARAM_PROB:
5850 /* If this corresponds to an ICMP_PROTOCOL_UNREACHABLE */
5851 if (icmp6->icmp6_code == ICMP6_PARAMPROB_NEXTHEADER &&
5852 (uchar_t *)ip6h + icmp6->icmp6_pptr ==
5853 (uchar_t *)nexthdrp) {
5854 if (tcp->tcp_state == TCPS_SYN_SENT ||
5855 tcp->tcp_state == TCPS_SYN_RCVD) {
5856 (void) tcp_clean_death(tcp, ECONNREFUSED);
5857 }
5858 break;
5859 }
5860 break;
5861
5862 case ICMP6_TIME_EXCEEDED:
5863 default:
5864 break;
5865 }
5866 freemsg(mp);
5867 }
5868
5869 /*
5870 * CALLED OUTSIDE OF SQUEUE! It can not follow any pointers that tcp might
5871 * change. But it can refer to fields like tcp_suna and tcp_snxt.
5872 *
5873 * Function tcp_verifyicmp is called as conn_verifyicmp to verify the ICMP
5874 * error messages received by IP. The message is always received on the correct
5875 * tcp_t.
5876 */
5877 /* ARGSUSED */
5878 boolean_t
5879 tcp_verifyicmp(conn_t *connp, void *arg2, icmph_t *icmph, icmp6_t *icmp6,
5880 ip_recv_attr_t *ira)
5881 {
5882 tcpha_t *tcpha = (tcpha_t *)arg2;
5883 uint32_t seq = ntohl(tcpha->tha_seq);
5884 tcp_t *tcp = connp->conn_tcp;
5885
5886 /*
5887 * TCP sequence number contained in payload of the ICMP error message
5888 * should be within the range SND.UNA <= SEG.SEQ < SND.NXT. Otherwise,
5889 * the message is either a stale ICMP error, or an attack from the
5890 * network. Fail the verification.
5891 */
5892 if (SEQ_LT(seq, tcp->tcp_suna) || SEQ_GEQ(seq, tcp->tcp_snxt))
5893 return (B_FALSE);
5894
5895 /* For "too big" we also check the ignore flag */
5896 if (ira->ira_flags & IRAF_IS_IPV4) {
5897 ASSERT(icmph != NULL);
5898 if (icmph->icmph_type == ICMP_DEST_UNREACHABLE &&
5899 icmph->icmph_code == ICMP_FRAGMENTATION_NEEDED &&
5900 tcp->tcp_tcps->tcps_ignore_path_mtu)
5901 return (B_FALSE);
5902 } else {
5903 ASSERT(icmp6 != NULL);
5904 if (icmp6->icmp6_type == ICMP6_PACKET_TOO_BIG &&
5905 tcp->tcp_tcps->tcps_ignore_path_mtu)
5906 return (B_FALSE);
5907 }
5908 return (B_TRUE);
5909 }