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 (c) 2014, 2016 by Delphix. All rights reserved.
25 * Copyright 2019 Joyent, Inc.
26 */
27
28 /* This file contains all TCP output processing functions. */
29
30 #include <sys/types.h>
31 #include <sys/stream.h>
32 #include <sys/strsun.h>
33 #include <sys/strsubr.h>
34 #include <sys/stropts.h>
35 #include <sys/strlog.h>
36 #define _SUN_TPI_VERSION 2
37 #include <sys/tihdr.h>
38 #include <sys/suntpi.h>
39 #include <sys/xti_inet.h>
40 #include <sys/timod.h>
41 #include <sys/pattr.h>
42 #include <sys/squeue_impl.h>
43 #include <sys/squeue.h>
44 #include <sys/sockio.h>
45 #include <sys/tsol/tnet.h>
46
47 #include <inet/common.h>
48 #include <inet/ip.h>
49 #include <inet/tcp.h>
50 #include <inet/tcp_impl.h>
51 #include <inet/snmpcom.h>
52 #include <inet/proto_set.h>
53 #include <inet/ipsec_impl.h>
54 #include <inet/ip_ndp.h>
55
56 static mblk_t *tcp_get_seg_mp(tcp_t *, uint32_t, int32_t *);
57 static void tcp_wput_cmdblk(queue_t *, mblk_t *);
58 static void tcp_wput_flush(tcp_t *, mblk_t *);
59 static void tcp_wput_iocdata(tcp_t *tcp, mblk_t *mp);
60 static int tcp_xmit_end(tcp_t *);
61 static int tcp_send(tcp_t *, const int, const int, const int,
62 const int, int *, uint32_t *, int *, mblk_t **, mblk_t *);
63 static void tcp_xmit_early_reset(char *, mblk_t *, uint32_t, uint32_t,
64 int, ip_recv_attr_t *, ip_stack_t *, conn_t *);
65 static boolean_t tcp_send_rst_chk(tcp_stack_t *);
66 static void tcp_process_shrunk_swnd(tcp_t *, uint32_t);
67 static void tcp_fill_header(tcp_t *, uchar_t *, int);
68
69 /*
70 * Functions called directly via squeue having a prototype of edesc_t.
71 */
72 static void tcp_wput_nondata(void *, mblk_t *, void *, ip_recv_attr_t *);
73 static void tcp_wput_ioctl(void *, mblk_t *, void *, ip_recv_attr_t *);
74 static void tcp_wput_proto(void *, mblk_t *, void *, ip_recv_attr_t *);
75
76 /*
77 * This controls how tiny a write must be before we try to copy it
78 * into the mblk on the tail of the transmit queue. Not much
79 * speedup is observed for values larger than sixteen. Zero will
80 * disable the optimisation.
81 */
82 static int tcp_tx_pull_len = 16;
83
84 int
85 tcp_wput(queue_t *q, mblk_t *mp)
86 {
87 conn_t *connp = Q_TO_CONN(q);
88 tcp_t *tcp;
89 void (*output_proc)();
90 t_scalar_t type;
91 uchar_t *rptr;
92 struct iocblk *iocp;
93 size_t size;
94
95 ASSERT(connp->conn_ref >= 2);
96
97 switch (DB_TYPE(mp)) {
98 case M_DATA:
99 tcp = connp->conn_tcp;
100 ASSERT(tcp != NULL);
101
102 size = msgdsize(mp);
103
104 mutex_enter(&tcp->tcp_non_sq_lock);
105 tcp->tcp_squeue_bytes += size;
106 if (TCP_UNSENT_BYTES(tcp) > connp->conn_sndbuf) {
107 tcp_setqfull(tcp);
108 }
109 mutex_exit(&tcp->tcp_non_sq_lock);
110
111 CONN_INC_REF(connp);
112 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, tcp_output, connp,
113 NULL, tcp_squeue_flag, SQTAG_TCP_OUTPUT);
114 return (0);
115
116 case M_CMD:
117 tcp_wput_cmdblk(q, mp);
118 return (0);
119
120 case M_PROTO:
121 case M_PCPROTO:
122 /*
123 * if it is a snmp message, don't get behind the squeue
124 */
125 tcp = connp->conn_tcp;
126 rptr = mp->b_rptr;
127 if ((mp->b_wptr - rptr) >= sizeof (t_scalar_t)) {
128 type = ((union T_primitives *)rptr)->type;
129 } else {
130 if (connp->conn_debug) {
131 (void) strlog(TCP_MOD_ID, 0, 1,
132 SL_ERROR|SL_TRACE,
133 "tcp_wput_proto, dropping one...");
134 }
135 freemsg(mp);
136 return (0);
137 }
138 if (type == T_SVR4_OPTMGMT_REQ) {
139 /*
140 * All Solaris components should pass a db_credp
141 * for this TPI message, hence we ASSERT.
142 * But in case there is some other M_PROTO that looks
143 * like a TPI message sent by some other kernel
144 * component, we check and return an error.
145 */
146 cred_t *cr = msg_getcred(mp, NULL);
147
148 ASSERT(cr != NULL);
149 if (cr == NULL) {
150 tcp_err_ack(tcp, mp, TSYSERR, EINVAL);
151 return (0);
152 }
153 if (snmpcom_req(q, mp, tcp_snmp_set, ip_snmp_get,
154 cr)) {
155 /*
156 * This was a SNMP request
157 */
158 return (0);
159 } else {
160 output_proc = tcp_wput_proto;
161 }
162 } else {
163 output_proc = tcp_wput_proto;
164 }
165 break;
166 case M_IOCTL:
167 /*
168 * Most ioctls can be processed right away without going via
169 * squeues - process them right here. Those that do require
170 * squeue (currently _SIOCSOCKFALLBACK)
171 * are processed by tcp_wput_ioctl().
172 */
173 iocp = (struct iocblk *)mp->b_rptr;
174 tcp = connp->conn_tcp;
175
176 switch (iocp->ioc_cmd) {
177 case TCP_IOC_ABORT_CONN:
178 tcp_ioctl_abort_conn(q, mp);
179 return (0);
180 case TI_GETPEERNAME:
181 case TI_GETMYNAME:
182 mi_copyin(q, mp, NULL,
183 SIZEOF_STRUCT(strbuf, iocp->ioc_flag));
184 return (0);
185
186 default:
187 output_proc = tcp_wput_ioctl;
188 break;
189 }
190 break;
191 default:
192 output_proc = tcp_wput_nondata;
193 break;
194 }
195
196 CONN_INC_REF(connp);
197 SQUEUE_ENTER_ONE(connp->conn_sqp, mp, output_proc, connp,
198 NULL, tcp_squeue_flag, SQTAG_TCP_WPUT_OTHER);
199 return (0);
200 }
201
202 /*
203 * The TCP normal data output path.
204 * NOTE: the logic of the fast path is duplicated from this function.
205 */
206 void
207 tcp_wput_data(tcp_t *tcp, mblk_t *mp, boolean_t urgent)
208 {
209 int len;
210 mblk_t *local_time;
211 mblk_t *mp1;
212 uint32_t snxt;
213 int tail_unsent;
214 int tcpstate;
215 int usable = 0;
216 mblk_t *xmit_tail;
217 int32_t mss;
218 int32_t num_sack_blk = 0;
219 int32_t total_hdr_len;
220 int32_t tcp_hdr_len;
221 int rc;
222 tcp_stack_t *tcps = tcp->tcp_tcps;
223 conn_t *connp = tcp->tcp_connp;
224 clock_t now = LBOLT_FASTPATH;
225
226 tcpstate = tcp->tcp_state;
227 if (mp == NULL) {
228 /*
229 * tcp_wput_data() with NULL mp should only be called when
230 * there is unsent data.
231 */
232 ASSERT(tcp->tcp_unsent > 0);
233 /* Really tacky... but we need this for detached closes. */
234 len = tcp->tcp_unsent;
235 goto data_null;
236 }
237
238 ASSERT(mp->b_datap->db_type == M_DATA);
239 /*
240 * Don't allow data after T_ORDREL_REQ or T_DISCON_REQ,
241 * or before a connection attempt has begun.
242 */
243 if (tcpstate < TCPS_SYN_SENT || tcpstate > TCPS_CLOSE_WAIT ||
244 (tcp->tcp_valid_bits & TCP_FSS_VALID) != 0) {
245 if ((tcp->tcp_valid_bits & TCP_FSS_VALID) != 0) {
246 #ifdef DEBUG
247 cmn_err(CE_WARN,
248 "tcp_wput_data: data after ordrel, %s",
249 tcp_display(tcp, NULL,
250 DISP_ADDR_AND_PORT));
251 #else
252 if (connp->conn_debug) {
253 (void) strlog(TCP_MOD_ID, 0, 1,
254 SL_TRACE|SL_ERROR,
255 "tcp_wput_data: data after ordrel, %s\n",
256 tcp_display(tcp, NULL,
257 DISP_ADDR_AND_PORT));
258 }
259 #endif /* DEBUG */
260 }
261 if (tcp->tcp_snd_zcopy_aware &&
262 (mp->b_datap->db_struioflag & STRUIO_ZCNOTIFY))
263 tcp_zcopy_notify(tcp);
264 freemsg(mp);
265 mutex_enter(&tcp->tcp_non_sq_lock);
266 if (tcp->tcp_flow_stopped &&
267 TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat) {
268 tcp_clrqfull(tcp);
269 }
270 mutex_exit(&tcp->tcp_non_sq_lock);
271 return;
272 }
273
274 /* Strip empties */
275 for (;;) {
276 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <=
277 (uintptr_t)INT_MAX);
278 len = (int)(mp->b_wptr - mp->b_rptr);
279 if (len > 0)
280 break;
281 mp1 = mp;
282 mp = mp->b_cont;
283 freeb(mp1);
284 if (mp == NULL) {
285 return;
286 }
287 }
288
289 /* If we are the first on the list ... */
290 if (tcp->tcp_xmit_head == NULL) {
291 tcp->tcp_xmit_head = mp;
292 tcp->tcp_xmit_tail = mp;
293 tcp->tcp_xmit_tail_unsent = len;
294 } else {
295 /* If tiny tx and room in txq tail, pullup to save mblks. */
296 struct datab *dp;
297
298 mp1 = tcp->tcp_xmit_last;
299 if (len < tcp_tx_pull_len &&
300 (dp = mp1->b_datap)->db_ref == 1 &&
301 dp->db_lim - mp1->b_wptr >= len) {
302 ASSERT(len > 0);
303 ASSERT(!mp1->b_cont);
304 if (len == 1) {
305 *mp1->b_wptr++ = *mp->b_rptr;
306 } else {
307 bcopy(mp->b_rptr, mp1->b_wptr, len);
308 mp1->b_wptr += len;
309 }
310 if (mp1 == tcp->tcp_xmit_tail)
311 tcp->tcp_xmit_tail_unsent += len;
312 mp1->b_cont = mp->b_cont;
313 if (tcp->tcp_snd_zcopy_aware &&
314 (mp->b_datap->db_struioflag & STRUIO_ZCNOTIFY))
315 mp1->b_datap->db_struioflag |= STRUIO_ZCNOTIFY;
316 freeb(mp);
317 mp = mp1;
318 } else {
319 tcp->tcp_xmit_last->b_cont = mp;
320 }
321 len += tcp->tcp_unsent;
322 }
323
324 /* Tack on however many more positive length mblks we have */
325 if ((mp1 = mp->b_cont) != NULL) {
326 do {
327 int tlen;
328 ASSERT((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <=
329 (uintptr_t)INT_MAX);
330 tlen = (int)(mp1->b_wptr - mp1->b_rptr);
331 if (tlen <= 0) {
332 mp->b_cont = mp1->b_cont;
333 freeb(mp1);
334 } else {
335 len += tlen;
336 mp = mp1;
337 }
338 } while ((mp1 = mp->b_cont) != NULL);
339 }
340 tcp->tcp_xmit_last = mp;
341 tcp->tcp_unsent = len;
342
343 if (urgent)
344 usable = 1;
345
346 data_null:
347 snxt = tcp->tcp_snxt;
348 xmit_tail = tcp->tcp_xmit_tail;
349 tail_unsent = tcp->tcp_xmit_tail_unsent;
350
351 /*
352 * Note that tcp_mss has been adjusted to take into account the
353 * timestamp option if applicable. Because SACK options do not
354 * appear in every TCP segments and they are of variable lengths,
355 * they cannot be included in tcp_mss. Thus we need to calculate
356 * the actual segment length when we need to send a segment which
357 * includes SACK options.
358 */
359 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
360 int32_t opt_len;
361
362 num_sack_blk = MIN(tcp->tcp_max_sack_blk,
363 tcp->tcp_num_sack_blk);
364 opt_len = num_sack_blk * sizeof (sack_blk_t) + TCPOPT_NOP_LEN *
365 2 + TCPOPT_HEADER_LEN;
366 mss = tcp->tcp_mss - opt_len;
367 total_hdr_len = connp->conn_ht_iphc_len + opt_len;
368 tcp_hdr_len = connp->conn_ht_ulp_len + opt_len;
369 } else {
370 mss = tcp->tcp_mss;
371 total_hdr_len = connp->conn_ht_iphc_len;
372 tcp_hdr_len = connp->conn_ht_ulp_len;
373 }
374
375 if ((tcp->tcp_suna == snxt) && !tcp->tcp_localnet &&
376 (TICK_TO_MSEC(now - tcp->tcp_last_recv_time) >= tcp->tcp_rto)) {
377 TCP_SET_INIT_CWND(tcp, mss, tcps->tcps_slow_start_after_idle);
378 }
379 if (tcpstate == TCPS_SYN_RCVD) {
380 /*
381 * The three-way connection establishment handshake is not
382 * complete yet. We want to queue the data for transmission
383 * after entering ESTABLISHED state (RFC793). A jump to
384 * "done" label effectively leaves data on the queue.
385 */
386 goto done;
387 } else {
388 int usable_r;
389
390 /*
391 * In the special case when cwnd is zero, which can only
392 * happen if the connection is ECN capable, return now.
393 * New segments is sent using tcp_timer(). The timer
394 * is set in tcp_input_data().
395 */
396 if (tcp->tcp_cwnd == 0) {
397 /*
398 * Note that tcp_cwnd is 0 before 3-way handshake is
399 * finished.
400 */
401 ASSERT(tcp->tcp_ecn_ok ||
402 tcp->tcp_state < TCPS_ESTABLISHED);
403 return;
404 }
405
406 /* NOTE: trouble if xmitting while SYN not acked? */
407 usable_r = snxt - tcp->tcp_suna;
408 usable_r = tcp->tcp_swnd - usable_r;
409
410 /*
411 * Check if the receiver has shrunk the window. If
412 * tcp_wput_data() with NULL mp is called, tcp_fin_sent
413 * cannot be set as there is unsent data, so FIN cannot
414 * be sent out. Otherwise, we need to take into account
415 * of FIN as it consumes an "invisible" sequence number.
416 */
417 ASSERT(tcp->tcp_fin_sent == 0);
418 if (usable_r < 0) {
419 /*
420 * The receiver has shrunk the window and we have sent
421 * -usable_r date beyond the window, re-adjust.
422 *
423 * If TCP window scaling is enabled, there can be
424 * round down error as the advertised receive window
425 * is actually right shifted n bits. This means that
426 * the lower n bits info is wiped out. It will look
427 * like the window is shrunk. Do a check here to
428 * see if the shrunk amount is actually within the
429 * error in window calculation. If it is, just
430 * return. Note that this check is inside the
431 * shrunk window check. This makes sure that even
432 * though tcp_process_shrunk_swnd() is not called,
433 * we will stop further processing.
434 */
435 if ((-usable_r >> tcp->tcp_snd_ws) > 0) {
436 tcp_process_shrunk_swnd(tcp, -usable_r);
437 }
438 return;
439 }
440
441 /* usable = MIN(swnd, cwnd) - unacked_bytes */
442 if (tcp->tcp_swnd > tcp->tcp_cwnd)
443 usable_r -= tcp->tcp_swnd - tcp->tcp_cwnd;
444
445 /* usable = MIN(usable, unsent) */
446 if (usable_r > len)
447 usable_r = len;
448
449 /* usable = MAX(usable, {1 for urgent, 0 for data}) */
450 if (usable_r > 0) {
451 usable = usable_r;
452 } else {
453 /* Bypass all other unnecessary processing. */
454 goto done;
455 }
456 }
457
458 local_time = (mblk_t *)(intptr_t)gethrtime();
459
460 /*
461 * "Our" Nagle Algorithm. This is not the same as in the old
462 * BSD. This is more in line with the true intent of Nagle.
463 *
464 * The conditions are:
465 * 1. The amount of unsent data (or amount of data which can be
466 * sent, whichever is smaller) is less than Nagle limit.
467 * 2. The last sent size is also less than Nagle limit.
468 * 3. There is unack'ed data.
469 * 4. Urgent pointer is not set. Send urgent data ignoring the
470 * Nagle algorithm. This reduces the probability that urgent
471 * bytes get "merged" together.
472 * 5. The app has not closed the connection. This eliminates the
473 * wait time of the receiving side waiting for the last piece of
474 * (small) data.
475 *
476 * If all are satisified, exit without sending anything. Note
477 * that Nagle limit can be smaller than 1 MSS. Nagle limit is
478 * the smaller of 1 MSS and global tcp_naglim_def (default to be
479 * 4095).
480 */
481 if (usable < (int)tcp->tcp_naglim &&
482 tcp->tcp_naglim > tcp->tcp_last_sent_len &&
483 snxt != tcp->tcp_suna &&
484 !(tcp->tcp_valid_bits & TCP_URG_VALID) &&
485 !(tcp->tcp_valid_bits & TCP_FSS_VALID)) {
486 goto done;
487 }
488
489 /*
490 * If tcp_zero_win_probe is not set and the tcp->tcp_cork option
491 * is set, then we have to force TCP not to send partial segment
492 * (smaller than MSS bytes). We are calculating the usable now
493 * based on full mss and will save the rest of remaining data for
494 * later. When tcp_zero_win_probe is set, TCP needs to send out
495 * something to do zero window probe.
496 */
497 if (tcp->tcp_cork && !tcp->tcp_zero_win_probe) {
498 if (usable < mss)
499 goto done;
500 usable = (usable / mss) * mss;
501 }
502
503 /* Update the latest receive window size in TCP header. */
504 tcp->tcp_tcpha->tha_win = htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
505
506 /* Send the packet. */
507 rc = tcp_send(tcp, mss, total_hdr_len, tcp_hdr_len,
508 num_sack_blk, &usable, &snxt, &tail_unsent, &xmit_tail,
509 local_time);
510
511 /* Pretend that all we were trying to send really got sent */
512 if (rc < 0 && tail_unsent < 0) {
513 do {
514 xmit_tail = xmit_tail->b_cont;
515 xmit_tail->b_prev = local_time;
516 ASSERT((uintptr_t)(xmit_tail->b_wptr -
517 xmit_tail->b_rptr) <= (uintptr_t)INT_MAX);
518 tail_unsent += (int)(xmit_tail->b_wptr -
519 xmit_tail->b_rptr);
520 } while (tail_unsent < 0);
521 }
522 done:;
523 tcp->tcp_xmit_tail = xmit_tail;
524 tcp->tcp_xmit_tail_unsent = tail_unsent;
525 len = tcp->tcp_snxt - snxt;
526 if (len) {
527 /*
528 * If new data was sent, need to update the notsack
529 * list, which is, afterall, data blocks that have
530 * not been sack'ed by the receiver. New data is
531 * not sack'ed.
532 */
533 if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) {
534 /* len is a negative value. */
535 tcp->tcp_pipe -= len;
536 tcp_notsack_update(&(tcp->tcp_notsack_list),
537 tcp->tcp_snxt, snxt,
538 &(tcp->tcp_num_notsack_blk),
539 &(tcp->tcp_cnt_notsack_list));
540 }
541 tcp->tcp_snxt = snxt + tcp->tcp_fin_sent;
542 tcp->tcp_rack = tcp->tcp_rnxt;
543 tcp->tcp_rack_cnt = 0;
544 if ((snxt + len) == tcp->tcp_suna) {
545 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
546 }
547 } else if (snxt == tcp->tcp_suna && tcp->tcp_swnd == 0) {
548 /*
549 * Didn't send anything. Make sure the timer is running
550 * so that we will probe a zero window.
551 */
552 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
553 }
554 /* Note that len is the amount we just sent but with a negative sign */
555 tcp->tcp_unsent += len;
556 mutex_enter(&tcp->tcp_non_sq_lock);
557 if (tcp->tcp_flow_stopped) {
558 if (TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat) {
559 tcp_clrqfull(tcp);
560 }
561 } else if (TCP_UNSENT_BYTES(tcp) >= connp->conn_sndbuf) {
562 if (!(tcp->tcp_detached))
563 tcp_setqfull(tcp);
564 }
565 mutex_exit(&tcp->tcp_non_sq_lock);
566 }
567
568 /*
569 * Initial STREAMS write side put() procedure for sockets. It tries to
570 * handle the T_CAPABILITY_REQ which sockfs sends down while setting
571 * up the socket without using the squeue. Non T_CAPABILITY_REQ messages
572 * are handled by tcp_wput() as usual.
573 *
574 * All further messages will also be handled by tcp_wput() because we cannot
575 * be sure that the above short cut is safe later.
576 */
577 int
578 tcp_wput_sock(queue_t *wq, mblk_t *mp)
579 {
580 conn_t *connp = Q_TO_CONN(wq);
581 tcp_t *tcp = connp->conn_tcp;
582 struct T_capability_req *car = (struct T_capability_req *)mp->b_rptr;
583
584 ASSERT(wq->q_qinfo == &tcp_sock_winit);
585 wq->q_qinfo = &tcp_winit;
586
587 ASSERT(IPCL_IS_TCP(connp));
588 ASSERT(TCP_IS_SOCKET(tcp));
589
590 if (DB_TYPE(mp) == M_PCPROTO &&
591 MBLKL(mp) == sizeof (struct T_capability_req) &&
592 car->PRIM_type == T_CAPABILITY_REQ) {
593 tcp_capability_req(tcp, mp);
594 return (0);
595 }
596
597 tcp_wput(wq, mp);
598 return (0);
599 }
600
601 /* ARGSUSED */
602 int
603 tcp_wput_fallback(queue_t *wq, mblk_t *mp)
604 {
605 #ifdef DEBUG
606 cmn_err(CE_CONT, "tcp_wput_fallback: Message during fallback \n");
607 #endif
608 freemsg(mp);
609 return (0);
610 }
611
612 /*
613 * Call by tcp_wput() to handle misc non M_DATA messages.
614 */
615 /* ARGSUSED */
616 static void
617 tcp_wput_nondata(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
618 {
619 conn_t *connp = (conn_t *)arg;
620 tcp_t *tcp = connp->conn_tcp;
621
622 ASSERT(DB_TYPE(mp) != M_IOCTL);
623 /*
624 * TCP is D_MP and qprocsoff() is done towards the end of the tcp_close.
625 * Once the close starts, streamhead and sockfs will not let any data
626 * packets come down (close ensures that there are no threads using the
627 * queue and no new threads will come down) but since qprocsoff()
628 * hasn't happened yet, a M_FLUSH or some non data message might
629 * get reflected back (in response to our own FLUSHRW) and get
630 * processed after tcp_close() is done. The conn would still be valid
631 * because a ref would have added but we need to check the state
632 * before actually processing the packet.
633 */
634 if (TCP_IS_DETACHED(tcp) || (tcp->tcp_state == TCPS_CLOSED)) {
635 freemsg(mp);
636 return;
637 }
638
639 switch (DB_TYPE(mp)) {
640 case M_IOCDATA:
641 tcp_wput_iocdata(tcp, mp);
642 break;
643 case M_FLUSH:
644 tcp_wput_flush(tcp, mp);
645 break;
646 default:
647 ip_wput_nondata(connp->conn_wq, mp);
648 break;
649 }
650 }
651
652 /* tcp_wput_flush is called by tcp_wput_nondata to handle M_FLUSH messages. */
653 static void
654 tcp_wput_flush(tcp_t *tcp, mblk_t *mp)
655 {
656 uchar_t fval = *mp->b_rptr;
657 mblk_t *tail;
658 conn_t *connp = tcp->tcp_connp;
659 queue_t *q = connp->conn_wq;
660
661 /* TODO: How should flush interact with urgent data? */
662 if ((fval & FLUSHW) && tcp->tcp_xmit_head != NULL &&
663 !(tcp->tcp_valid_bits & TCP_URG_VALID)) {
664 /*
665 * Flush only data that has not yet been put on the wire. If
666 * we flush data that we have already transmitted, life, as we
667 * know it, may come to an end.
668 */
669 tail = tcp->tcp_xmit_tail;
670 tail->b_wptr -= tcp->tcp_xmit_tail_unsent;
671 tcp->tcp_xmit_tail_unsent = 0;
672 tcp->tcp_unsent = 0;
673 if (tail->b_wptr != tail->b_rptr)
674 tail = tail->b_cont;
675 if (tail) {
676 mblk_t **excess = &tcp->tcp_xmit_head;
677 for (;;) {
678 mblk_t *mp1 = *excess;
679 if (mp1 == tail)
680 break;
681 tcp->tcp_xmit_tail = mp1;
682 tcp->tcp_xmit_last = mp1;
683 excess = &mp1->b_cont;
684 }
685 *excess = NULL;
686 tcp_close_mpp(&tail);
687 if (tcp->tcp_snd_zcopy_aware)
688 tcp_zcopy_notify(tcp);
689 }
690 /*
691 * We have no unsent data, so unsent must be less than
692 * conn_sndlowat, so re-enable flow.
693 */
694 mutex_enter(&tcp->tcp_non_sq_lock);
695 if (tcp->tcp_flow_stopped) {
696 tcp_clrqfull(tcp);
697 }
698 mutex_exit(&tcp->tcp_non_sq_lock);
699 }
700 /*
701 * TODO: you can't just flush these, you have to increase rwnd for one
702 * thing. For another, how should urgent data interact?
703 */
704 if (fval & FLUSHR) {
705 *mp->b_rptr = fval & ~FLUSHW;
706 /* XXX */
707 qreply(q, mp);
708 return;
709 }
710 freemsg(mp);
711 }
712
713 /*
714 * tcp_wput_iocdata is called by tcp_wput_nondata to handle all M_IOCDATA
715 * messages.
716 */
717 static void
718 tcp_wput_iocdata(tcp_t *tcp, mblk_t *mp)
719 {
720 mblk_t *mp1;
721 struct iocblk *iocp = (struct iocblk *)mp->b_rptr;
722 STRUCT_HANDLE(strbuf, sb);
723 uint_t addrlen;
724 conn_t *connp = tcp->tcp_connp;
725 queue_t *q = connp->conn_wq;
726
727 /* Make sure it is one of ours. */
728 switch (iocp->ioc_cmd) {
729 case TI_GETMYNAME:
730 case TI_GETPEERNAME:
731 break;
732 default:
733 /*
734 * If the conn is closing, then error the ioctl here. Otherwise
735 * use the CONN_IOCTLREF_* macros to hold off tcp_close until
736 * we're done here.
737 */
738 mutex_enter(&connp->conn_lock);
739 if (connp->conn_state_flags & CONN_CLOSING) {
740 mutex_exit(&connp->conn_lock);
741 iocp->ioc_error = EINVAL;
742 mp->b_datap->db_type = M_IOCNAK;
743 iocp->ioc_count = 0;
744 qreply(q, mp);
745 return;
746 }
747
748 CONN_INC_IOCTLREF_LOCKED(connp);
749 ip_wput_nondata(q, mp);
750 CONN_DEC_IOCTLREF(connp);
751 return;
752 }
753 switch (mi_copy_state(q, mp, &mp1)) {
754 case -1:
755 return;
756 case MI_COPY_CASE(MI_COPY_IN, 1):
757 break;
758 case MI_COPY_CASE(MI_COPY_OUT, 1):
759 /* Copy out the strbuf. */
760 mi_copyout(q, mp);
761 return;
762 case MI_COPY_CASE(MI_COPY_OUT, 2):
763 /* All done. */
764 mi_copy_done(q, mp, 0);
765 return;
766 default:
767 mi_copy_done(q, mp, EPROTO);
768 return;
769 }
770 /* Check alignment of the strbuf */
771 if (!OK_32PTR(mp1->b_rptr)) {
772 mi_copy_done(q, mp, EINVAL);
773 return;
774 }
775
776 STRUCT_SET_HANDLE(sb, iocp->ioc_flag, (void *)mp1->b_rptr);
777
778 if (connp->conn_family == AF_INET)
779 addrlen = sizeof (sin_t);
780 else
781 addrlen = sizeof (sin6_t);
782
783 if (STRUCT_FGET(sb, maxlen) < addrlen) {
784 mi_copy_done(q, mp, EINVAL);
785 return;
786 }
787
788 switch (iocp->ioc_cmd) {
789 case TI_GETMYNAME:
790 break;
791 case TI_GETPEERNAME:
792 if (tcp->tcp_state < TCPS_SYN_RCVD) {
793 mi_copy_done(q, mp, ENOTCONN);
794 return;
795 }
796 break;
797 }
798 mp1 = mi_copyout_alloc(q, mp, STRUCT_FGETP(sb, buf), addrlen, B_TRUE);
799 if (!mp1)
800 return;
801
802 STRUCT_FSET(sb, len, addrlen);
803 switch (((struct iocblk *)mp->b_rptr)->ioc_cmd) {
804 case TI_GETMYNAME:
805 (void) conn_getsockname(connp, (struct sockaddr *)mp1->b_wptr,
806 &addrlen);
807 break;
808 case TI_GETPEERNAME:
809 (void) conn_getpeername(connp, (struct sockaddr *)mp1->b_wptr,
810 &addrlen);
811 break;
812 }
813 mp1->b_wptr += addrlen;
814 /* Copy out the address */
815 mi_copyout(q, mp);
816 }
817
818 /*
819 * tcp_wput_ioctl is called by tcp_wput_nondata() to handle all M_IOCTL
820 * messages.
821 */
822 /* ARGSUSED */
823 static void
824 tcp_wput_ioctl(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
825 {
826 conn_t *connp = (conn_t *)arg;
827 tcp_t *tcp = connp->conn_tcp;
828 queue_t *q = connp->conn_wq;
829 struct iocblk *iocp;
830
831 ASSERT(DB_TYPE(mp) == M_IOCTL);
832 /*
833 * Try and ASSERT the minimum possible references on the
834 * conn early enough. Since we are executing on write side,
835 * the connection is obviously not detached and that means
836 * there is a ref each for TCP and IP. Since we are behind
837 * the squeue, the minimum references needed are 3. If the
838 * conn is in classifier hash list, there should be an
839 * extra ref for that (we check both the possibilities).
840 */
841 ASSERT((connp->conn_fanout != NULL && connp->conn_ref >= 4) ||
842 (connp->conn_fanout == NULL && connp->conn_ref >= 3));
843
844 iocp = (struct iocblk *)mp->b_rptr;
845 switch (iocp->ioc_cmd) {
846 case _SIOCSOCKFALLBACK:
847 /*
848 * Either sockmod is about to be popped and the socket
849 * would now be treated as a plain stream, or a module
850 * is about to be pushed so we could no longer use read-
851 * side synchronous streams for fused loopback tcp.
852 * Drain any queued data and disable direct sockfs
853 * interface from now on.
854 */
855 if (!tcp->tcp_issocket) {
856 DB_TYPE(mp) = M_IOCNAK;
857 iocp->ioc_error = EINVAL;
858 } else {
859 tcp_use_pure_tpi(tcp);
860 DB_TYPE(mp) = M_IOCACK;
861 iocp->ioc_error = 0;
862 }
863 iocp->ioc_count = 0;
864 iocp->ioc_rval = 0;
865 qreply(q, mp);
866 return;
867 }
868
869 /*
870 * If the conn is closing, then error the ioctl here. Otherwise bump the
871 * conn_ioctlref to hold off tcp_close until we're done here.
872 */
873 mutex_enter(&(connp)->conn_lock);
874 if ((connp)->conn_state_flags & CONN_CLOSING) {
875 mutex_exit(&(connp)->conn_lock);
876 iocp->ioc_error = EINVAL;
877 mp->b_datap->db_type = M_IOCNAK;
878 iocp->ioc_count = 0;
879 qreply(q, mp);
880 return;
881 }
882
883 CONN_INC_IOCTLREF_LOCKED(connp);
884 ip_wput_nondata(q, mp);
885 CONN_DEC_IOCTLREF(connp);
886 }
887
888 /*
889 * This routine is called by tcp_wput() to handle all TPI requests.
890 */
891 /* ARGSUSED */
892 static void
893 tcp_wput_proto(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
894 {
895 conn_t *connp = (conn_t *)arg;
896 tcp_t *tcp = connp->conn_tcp;
897 union T_primitives *tprim = (union T_primitives *)mp->b_rptr;
898 uchar_t *rptr;
899 t_scalar_t type;
900 cred_t *cr;
901
902 /*
903 * Try and ASSERT the minimum possible references on the
904 * conn early enough. Since we are executing on write side,
905 * the connection is obviously not detached and that means
906 * there is a ref each for TCP and IP. Since we are behind
907 * the squeue, the minimum references needed are 3. If the
908 * conn is in classifier hash list, there should be an
909 * extra ref for that (we check both the possibilities).
910 */
911 ASSERT((connp->conn_fanout != NULL && connp->conn_ref >= 4) ||
912 (connp->conn_fanout == NULL && connp->conn_ref >= 3));
913
914 rptr = mp->b_rptr;
915 ASSERT((uintptr_t)(mp->b_wptr - rptr) <= (uintptr_t)INT_MAX);
916 if ((mp->b_wptr - rptr) >= sizeof (t_scalar_t)) {
917 type = ((union T_primitives *)rptr)->type;
918 if (type == T_EXDATA_REQ) {
919 tcp_output_urgent(connp, mp, arg2, NULL);
920 } else if (type != T_DATA_REQ) {
921 goto non_urgent_data;
922 } else {
923 /* TODO: options, flags, ... from user */
924 /* Set length to zero for reclamation below */
925 tcp_wput_data(tcp, mp->b_cont, B_TRUE);
926 freeb(mp);
927 }
928 return;
929 } else {
930 if (connp->conn_debug) {
931 (void) strlog(TCP_MOD_ID, 0, 1, SL_ERROR|SL_TRACE,
932 "tcp_wput_proto, dropping one...");
933 }
934 freemsg(mp);
935 return;
936 }
937
938 non_urgent_data:
939
940 switch ((int)tprim->type) {
941 case O_T_BIND_REQ: /* bind request */
942 case T_BIND_REQ: /* new semantics bind request */
943 tcp_tpi_bind(tcp, mp);
944 break;
945 case T_UNBIND_REQ: /* unbind request */
946 tcp_tpi_unbind(tcp, mp);
947 break;
948 case O_T_CONN_RES: /* old connection response XXX */
949 case T_CONN_RES: /* connection response */
950 tcp_tli_accept(tcp, mp);
951 break;
952 case T_CONN_REQ: /* connection request */
953 tcp_tpi_connect(tcp, mp);
954 break;
955 case T_DISCON_REQ: /* disconnect request */
956 tcp_disconnect(tcp, mp);
957 break;
958 case T_CAPABILITY_REQ:
959 tcp_capability_req(tcp, mp); /* capability request */
960 break;
961 case T_INFO_REQ: /* information request */
962 tcp_info_req(tcp, mp);
963 break;
964 case T_SVR4_OPTMGMT_REQ: /* manage options req */
965 case T_OPTMGMT_REQ:
966 /*
967 * Note: no support for snmpcom_req() through new
968 * T_OPTMGMT_REQ. See comments in ip.c
969 */
970
971 /*
972 * All Solaris components should pass a db_credp
973 * for this TPI message, hence we ASSERT.
974 * But in case there is some other M_PROTO that looks
975 * like a TPI message sent by some other kernel
976 * component, we check and return an error.
977 */
978 cr = msg_getcred(mp, NULL);
979 ASSERT(cr != NULL);
980 if (cr == NULL) {
981 tcp_err_ack(tcp, mp, TSYSERR, EINVAL);
982 return;
983 }
984 /*
985 * If EINPROGRESS is returned, the request has been queued
986 * for subsequent processing by ip_restart_optmgmt(), which
987 * will do the CONN_DEC_REF().
988 */
989 if ((int)tprim->type == T_SVR4_OPTMGMT_REQ) {
990 svr4_optcom_req(connp->conn_wq, mp, cr, &tcp_opt_obj);
991 } else {
992 tpi_optcom_req(connp->conn_wq, mp, cr, &tcp_opt_obj);
993 }
994 break;
995
996 case T_UNITDATA_REQ: /* unitdata request */
997 tcp_err_ack(tcp, mp, TNOTSUPPORT, 0);
998 break;
999 case T_ORDREL_REQ: /* orderly release req */
1000 freemsg(mp);
1001
1002 if (tcp->tcp_fused)
1003 tcp_unfuse(tcp);
1004
1005 if (tcp_xmit_end(tcp) != 0) {
1006 /*
1007 * We were crossing FINs and got a reset from
1008 * the other side. Just ignore it.
1009 */
1010 if (connp->conn_debug) {
1011 (void) strlog(TCP_MOD_ID, 0, 1,
1012 SL_ERROR|SL_TRACE,
1013 "tcp_wput_proto, T_ORDREL_REQ out of "
1014 "state %s",
1015 tcp_display(tcp, NULL,
1016 DISP_ADDR_AND_PORT));
1017 }
1018 }
1019 break;
1020 case T_ADDR_REQ:
1021 tcp_addr_req(tcp, mp);
1022 break;
1023 default:
1024 if (connp->conn_debug) {
1025 (void) strlog(TCP_MOD_ID, 0, 1, SL_ERROR|SL_TRACE,
1026 "tcp_wput_proto, bogus TPI msg, type %d",
1027 tprim->type);
1028 }
1029 /*
1030 * We used to M_ERROR. Sending TNOTSUPPORT gives the user
1031 * to recover.
1032 */
1033 tcp_err_ack(tcp, mp, TNOTSUPPORT, 0);
1034 break;
1035 }
1036 }
1037
1038 /*
1039 * Handle special out-of-band ioctl requests (see PSARC/2008/265).
1040 */
1041 static void
1042 tcp_wput_cmdblk(queue_t *q, mblk_t *mp)
1043 {
1044 void *data;
1045 mblk_t *datamp = mp->b_cont;
1046 conn_t *connp = Q_TO_CONN(q);
1047 tcp_t *tcp = connp->conn_tcp;
1048 cmdblk_t *cmdp = (cmdblk_t *)mp->b_rptr;
1049
1050 if (datamp == NULL || MBLKL(datamp) < cmdp->cb_len) {
1051 cmdp->cb_error = EPROTO;
1052 qreply(q, mp);
1053 return;
1054 }
1055
1056 data = datamp->b_rptr;
1057
1058 switch (cmdp->cb_cmd) {
1059 case TI_GETPEERNAME:
1060 if (tcp->tcp_state < TCPS_SYN_RCVD)
1061 cmdp->cb_error = ENOTCONN;
1062 else
1063 cmdp->cb_error = conn_getpeername(connp, data,
1064 &cmdp->cb_len);
1065 break;
1066 case TI_GETMYNAME:
1067 cmdp->cb_error = conn_getsockname(connp, data, &cmdp->cb_len);
1068 break;
1069 default:
1070 cmdp->cb_error = EINVAL;
1071 break;
1072 }
1073
1074 qreply(q, mp);
1075 }
1076
1077 /*
1078 * The TCP fast path write put procedure.
1079 * NOTE: the logic of the fast path is duplicated from tcp_wput_data()
1080 */
1081 /* ARGSUSED */
1082 void
1083 tcp_output(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1084 {
1085 int len;
1086 int hdrlen;
1087 int plen;
1088 mblk_t *mp1;
1089 uchar_t *rptr;
1090 uint32_t snxt;
1091 tcpha_t *tcpha;
1092 struct datab *db;
1093 uint32_t suna;
1094 uint32_t mss;
1095 ipaddr_t *dst;
1096 ipaddr_t *src;
1097 uint32_t sum;
1098 int usable;
1099 conn_t *connp = (conn_t *)arg;
1100 tcp_t *tcp = connp->conn_tcp;
1101 uint32_t msize;
1102 tcp_stack_t *tcps = tcp->tcp_tcps;
1103 ip_xmit_attr_t *ixa;
1104 clock_t now;
1105
1106 /*
1107 * Try and ASSERT the minimum possible references on the
1108 * conn early enough. Since we are executing on write side,
1109 * the connection is obviously not detached and that means
1110 * there is a ref each for TCP and IP. Since we are behind
1111 * the squeue, the minimum references needed are 3. If the
1112 * conn is in classifier hash list, there should be an
1113 * extra ref for that (we check both the possibilities).
1114 */
1115 ASSERT((connp->conn_fanout != NULL && connp->conn_ref >= 4) ||
1116 (connp->conn_fanout == NULL && connp->conn_ref >= 3));
1117
1118 ASSERT(DB_TYPE(mp) == M_DATA);
1119 msize = (mp->b_cont == NULL) ? MBLKL(mp) : msgdsize(mp);
1120
1121 mutex_enter(&tcp->tcp_non_sq_lock);
1122 tcp->tcp_squeue_bytes -= msize;
1123 mutex_exit(&tcp->tcp_non_sq_lock);
1124
1125 /* Bypass tcp protocol for fused tcp loopback */
1126 if (tcp->tcp_fused && tcp_fuse_output(tcp, mp, msize))
1127 return;
1128
1129 mss = tcp->tcp_mss;
1130 /*
1131 * If ZEROCOPY has turned off, try not to send any zero-copy message
1132 * down. Do backoff, now.
1133 */
1134 if (tcp->tcp_snd_zcopy_aware && !tcp->tcp_snd_zcopy_on)
1135 mp = tcp_zcopy_backoff(tcp, mp, B_FALSE);
1136
1137
1138 ASSERT((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)INT_MAX);
1139 len = (int)(mp->b_wptr - mp->b_rptr);
1140
1141 /*
1142 * Criteria for fast path:
1143 *
1144 * 1. no unsent data
1145 * 2. single mblk in request
1146 * 3. connection established
1147 * 4. data in mblk
1148 * 5. len <= mss
1149 * 6. no tcp_valid bits
1150 */
1151 if ((tcp->tcp_unsent != 0) ||
1152 (tcp->tcp_cork) ||
1153 (mp->b_cont != NULL) ||
1154 (tcp->tcp_state != TCPS_ESTABLISHED) ||
1155 (len == 0) ||
1156 (len > mss) ||
1157 (tcp->tcp_valid_bits != 0)) {
1158 tcp_wput_data(tcp, mp, B_FALSE);
1159 return;
1160 }
1161
1162 ASSERT(tcp->tcp_xmit_tail_unsent == 0);
1163 ASSERT(tcp->tcp_fin_sent == 0);
1164
1165 /* queue new packet onto retransmission queue */
1166 if (tcp->tcp_xmit_head == NULL) {
1167 tcp->tcp_xmit_head = mp;
1168 } else {
1169 tcp->tcp_xmit_last->b_cont = mp;
1170 }
1171 tcp->tcp_xmit_last = mp;
1172 tcp->tcp_xmit_tail = mp;
1173
1174 /* find out how much we can send */
1175 /* BEGIN CSTYLED */
1176 /*
1177 * un-acked usable
1178 * |--------------|-----------------|
1179 * tcp_suna tcp_snxt tcp_suna+tcp_swnd
1180 */
1181 /* END CSTYLED */
1182
1183 /* start sending from tcp_snxt */
1184 snxt = tcp->tcp_snxt;
1185
1186 /*
1187 * Check to see if this connection has been idle for some time and no
1188 * ACK is expected. If so, then the congestion window size is no longer
1189 * meaningfully tied to current network conditions.
1190 *
1191 * We reinitialize tcp_cwnd, and slow start again to get back the
1192 * connection's "self-clock" as described in Van Jacobson's 1988 paper
1193 * "Congestion avoidance and control".
1194 */
1195 now = LBOLT_FASTPATH;
1196 if ((tcp->tcp_suna == snxt) && !tcp->tcp_localnet &&
1197 (TICK_TO_MSEC(now - tcp->tcp_last_recv_time) >= tcp->tcp_rto)) {
1198 TCP_SET_INIT_CWND(tcp, mss, tcps->tcps_slow_start_after_idle);
1199 }
1200
1201 usable = tcp->tcp_swnd; /* tcp window size */
1202 if (usable > tcp->tcp_cwnd)
1203 usable = tcp->tcp_cwnd; /* congestion window smaller */
1204 usable -= snxt; /* subtract stuff already sent */
1205 suna = tcp->tcp_suna;
1206 usable += suna;
1207 /* usable can be < 0 if the congestion window is smaller */
1208 if (len > usable) {
1209 /* Can't send complete M_DATA in one shot */
1210 goto slow;
1211 }
1212
1213 mutex_enter(&tcp->tcp_non_sq_lock);
1214 if (tcp->tcp_flow_stopped &&
1215 TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat) {
1216 tcp_clrqfull(tcp);
1217 }
1218 mutex_exit(&tcp->tcp_non_sq_lock);
1219
1220 /*
1221 * determine if anything to send (Nagle).
1222 *
1223 * 1. len < tcp_mss (i.e. small)
1224 * 2. unacknowledged data present
1225 * 3. len < nagle limit
1226 * 4. last packet sent < nagle limit (previous packet sent)
1227 */
1228 if ((len < mss) && (snxt != suna) &&
1229 (len < (int)tcp->tcp_naglim) &&
1230 (tcp->tcp_last_sent_len < tcp->tcp_naglim)) {
1231 /*
1232 * This was the first unsent packet and normally
1233 * mss < xmit_hiwater so there is no need to worry
1234 * about flow control. The next packet will go
1235 * through the flow control check in tcp_wput_data().
1236 */
1237 /* leftover work from above */
1238 tcp->tcp_unsent = len;
1239 tcp->tcp_xmit_tail_unsent = len;
1240
1241 return;
1242 }
1243
1244 /*
1245 * len <= tcp->tcp_mss && len == unsent so no sender silly window. Can
1246 * send now.
1247 */
1248
1249 if (snxt == suna) {
1250 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
1251 }
1252
1253 /* we have always sent something */
1254 tcp->tcp_rack_cnt = 0;
1255
1256 tcp->tcp_snxt = snxt + len;
1257 tcp->tcp_rack = tcp->tcp_rnxt;
1258
1259 if ((mp1 = dupb(mp)) == 0)
1260 goto no_memory;
1261 mp->b_prev = (mblk_t *)(intptr_t)gethrtime();
1262 mp->b_next = (mblk_t *)(uintptr_t)snxt;
1263
1264 /* adjust tcp header information */
1265 tcpha = tcp->tcp_tcpha;
1266 tcpha->tha_flags = (TH_ACK|TH_PUSH);
1267
1268 sum = len + connp->conn_ht_ulp_len + connp->conn_sum;
1269 sum = (sum >> 16) + (sum & 0xFFFF);
1270 tcpha->tha_sum = htons(sum);
1271
1272 tcpha->tha_seq = htonl(snxt);
1273
1274 TCPS_BUMP_MIB(tcps, tcpOutDataSegs);
1275 TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, len);
1276 BUMP_LOCAL(tcp->tcp_obsegs);
1277
1278 /* Update the latest receive window size in TCP header. */
1279 tcpha->tha_win = htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
1280
1281 tcp->tcp_last_sent_len = (ushort_t)len;
1282
1283 plen = len + connp->conn_ht_iphc_len;
1284
1285 ixa = connp->conn_ixa;
1286 ixa->ixa_pktlen = plen;
1287
1288 if (ixa->ixa_flags & IXAF_IS_IPV4) {
1289 tcp->tcp_ipha->ipha_length = htons(plen);
1290 } else {
1291 tcp->tcp_ip6h->ip6_plen = htons(plen - IPV6_HDR_LEN);
1292 }
1293
1294 /* see if we need to allocate a mblk for the headers */
1295 hdrlen = connp->conn_ht_iphc_len;
1296 rptr = mp1->b_rptr - hdrlen;
1297 db = mp1->b_datap;
1298 if ((db->db_ref != 2) || rptr < db->db_base ||
1299 (!OK_32PTR(rptr))) {
1300 /* NOTE: we assume allocb returns an OK_32PTR */
1301 mp = allocb(hdrlen + tcps->tcps_wroff_xtra, BPRI_MED);
1302 if (!mp) {
1303 freemsg(mp1);
1304 goto no_memory;
1305 }
1306 mp->b_cont = mp1;
1307 mp1 = mp;
1308 /* Leave room for Link Level header */
1309 rptr = &mp1->b_rptr[tcps->tcps_wroff_xtra];
1310 mp1->b_wptr = &rptr[hdrlen];
1311 }
1312 mp1->b_rptr = rptr;
1313
1314 /* Fill in the timestamp option. */
1315 if (tcp->tcp_snd_ts_ok) {
1316 U32_TO_BE32(now,
1317 (char *)tcpha + TCP_MIN_HEADER_LENGTH + 4);
1318 U32_TO_BE32(tcp->tcp_ts_recent,
1319 (char *)tcpha + TCP_MIN_HEADER_LENGTH + 8);
1320 } else {
1321 ASSERT(connp->conn_ht_ulp_len == TCP_MIN_HEADER_LENGTH);
1322 }
1323
1324 /* copy header into outgoing packet */
1325 dst = (ipaddr_t *)rptr;
1326 src = (ipaddr_t *)connp->conn_ht_iphc;
1327 dst[0] = src[0];
1328 dst[1] = src[1];
1329 dst[2] = src[2];
1330 dst[3] = src[3];
1331 dst[4] = src[4];
1332 dst[5] = src[5];
1333 dst[6] = src[6];
1334 dst[7] = src[7];
1335 dst[8] = src[8];
1336 dst[9] = src[9];
1337 if (hdrlen -= 40) {
1338 hdrlen >>= 2;
1339 dst += 10;
1340 src += 10;
1341 do {
1342 *dst++ = *src++;
1343 } while (--hdrlen);
1344 }
1345
1346 /*
1347 * Set the ECN info in the TCP header. Note that this
1348 * is not the template header.
1349 */
1350 if (tcp->tcp_ecn_ok) {
1351 TCP_SET_ECT(tcp, rptr);
1352
1353 tcpha = (tcpha_t *)(rptr + ixa->ixa_ip_hdr_length);
1354 if (tcp->tcp_ecn_echo_on)
1355 tcpha->tha_flags |= TH_ECE;
1356 if (tcp->tcp_cwr && !tcp->tcp_ecn_cwr_sent) {
1357 tcpha->tha_flags |= TH_CWR;
1358 tcp->tcp_ecn_cwr_sent = B_TRUE;
1359 }
1360 }
1361
1362 if (tcp->tcp_ip_forward_progress) {
1363 tcp->tcp_ip_forward_progress = B_FALSE;
1364 connp->conn_ixa->ixa_flags |= IXAF_REACH_CONF;
1365 } else {
1366 connp->conn_ixa->ixa_flags &= ~IXAF_REACH_CONF;
1367 }
1368 tcp_send_data(tcp, mp1);
1369 return;
1370
1371 /*
1372 * If we ran out of memory, we pretend to have sent the packet
1373 * and that it was lost on the wire.
1374 */
1375 no_memory:
1376 return;
1377
1378 slow:
1379 /* leftover work from above */
1380 tcp->tcp_unsent = len;
1381 tcp->tcp_xmit_tail_unsent = len;
1382 tcp_wput_data(tcp, NULL, B_FALSE);
1383 }
1384
1385 /* ARGSUSED2 */
1386 void
1387 tcp_output_urgent(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1388 {
1389 int len;
1390 uint32_t msize;
1391 conn_t *connp = (conn_t *)arg;
1392 tcp_t *tcp = connp->conn_tcp;
1393
1394 msize = msgdsize(mp);
1395
1396 len = msize - 1;
1397 if (len < 0) {
1398 freemsg(mp);
1399 return;
1400 }
1401
1402 /*
1403 * Try to force urgent data out on the wire. Even if we have unsent
1404 * data this will at least send the urgent flag.
1405 * XXX does not handle more flag correctly.
1406 */
1407 len += tcp->tcp_unsent;
1408 len += tcp->tcp_snxt;
1409 tcp->tcp_urg = len;
1410 tcp->tcp_valid_bits |= TCP_URG_VALID;
1411
1412 /* Bypass tcp protocol for fused tcp loopback */
1413 if (tcp->tcp_fused && tcp_fuse_output(tcp, mp, msize))
1414 return;
1415
1416 /* Strip off the T_EXDATA_REQ if the data is from TPI */
1417 if (DB_TYPE(mp) != M_DATA) {
1418 mblk_t *mp1 = mp;
1419 ASSERT(!IPCL_IS_NONSTR(connp));
1420 mp = mp->b_cont;
1421 freeb(mp1);
1422 }
1423 tcp_wput_data(tcp, mp, B_TRUE);
1424 }
1425
1426 /*
1427 * Called by streams close routine via squeues when our client blows off its
1428 * descriptor, we take this to mean: "close the stream state NOW, close the tcp
1429 * connection politely" When SO_LINGER is set (with a non-zero linger time and
1430 * it is not a nonblocking socket) then this routine sleeps until the FIN is
1431 * acked.
1432 *
1433 * NOTE: tcp_close potentially returns error when lingering.
1434 * However, the stream head currently does not pass these errors
1435 * to the application. 4.4BSD only returns EINTR and EWOULDBLOCK
1436 * errors to the application (from tsleep()) and not errors
1437 * like ECONNRESET caused by receiving a reset packet.
1438 */
1439
1440 /* ARGSUSED */
1441 void
1442 tcp_close_output(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1443 {
1444 char *msg;
1445 conn_t *connp = (conn_t *)arg;
1446 tcp_t *tcp = connp->conn_tcp;
1447 clock_t delta = 0;
1448 tcp_stack_t *tcps = tcp->tcp_tcps;
1449
1450 /*
1451 * When a non-STREAMS socket is being closed, it does not always
1452 * stick around waiting for tcp_close_output to run and can therefore
1453 * have dropped a reference already. So adjust the asserts accordingly.
1454 */
1455 ASSERT((connp->conn_fanout != NULL &&
1456 connp->conn_ref >= (IPCL_IS_NONSTR(connp) ? 3 : 4)) ||
1457 (connp->conn_fanout == NULL &&
1458 connp->conn_ref >= (IPCL_IS_NONSTR(connp) ? 2 : 3)));
1459
1460 mutex_enter(&tcp->tcp_eager_lock);
1461 if (tcp->tcp_conn_req_cnt_q0 != 0 || tcp->tcp_conn_req_cnt_q != 0) {
1462 /*
1463 * Cleanup for listener. For non-STREAM sockets sockfs will
1464 * close all the eagers on 'q', so in that case only deal
1465 * with 'q0'.
1466 */
1467 tcp_eager_cleanup(tcp, IPCL_IS_NONSTR(connp) ? 1 : 0);
1468 tcp->tcp_wait_for_eagers = 1;
1469 }
1470 mutex_exit(&tcp->tcp_eager_lock);
1471
1472 tcp->tcp_lso = B_FALSE;
1473
1474 msg = NULL;
1475 switch (tcp->tcp_state) {
1476 case TCPS_CLOSED:
1477 case TCPS_IDLE:
1478 break;
1479 case TCPS_BOUND:
1480 if (tcp->tcp_listener != NULL) {
1481 ASSERT(IPCL_IS_NONSTR(connp));
1482 /*
1483 * Unlink from the listener and drop the reference
1484 * put on it by the eager. tcp_closei_local will not
1485 * do it because tcp_tconnind_started is TRUE.
1486 */
1487 mutex_enter(&tcp->tcp_saved_listener->tcp_eager_lock);
1488 tcp_eager_unlink(tcp);
1489 mutex_exit(&tcp->tcp_saved_listener->tcp_eager_lock);
1490 CONN_DEC_REF(tcp->tcp_saved_listener->tcp_connp);
1491 }
1492 break;
1493 case TCPS_LISTEN:
1494 break;
1495 case TCPS_SYN_SENT:
1496 msg = "tcp_close, during connect";
1497 break;
1498 case TCPS_SYN_RCVD:
1499 /*
1500 * Close during the connect 3-way handshake
1501 * but here there may or may not be pending data
1502 * already on queue. Process almost same as in
1503 * the ESTABLISHED state.
1504 */
1505 /* FALLTHRU */
1506 default:
1507 if (tcp->tcp_fused)
1508 tcp_unfuse(tcp);
1509
1510 /*
1511 * If SO_LINGER has set a zero linger time, abort the
1512 * connection with a reset.
1513 */
1514 if (connp->conn_linger && connp->conn_lingertime == 0) {
1515 msg = "tcp_close, zero lingertime";
1516 break;
1517 }
1518
1519 /*
1520 * Abort connection if there is unread data queued.
1521 */
1522 if (tcp->tcp_rcv_list || tcp->tcp_reass_head) {
1523 msg = "tcp_close, unread data";
1524 break;
1525 }
1526
1527 /*
1528 * Abort connection if it is being closed without first
1529 * being accepted. This can happen if a listening non-STREAM
1530 * socket wants to get rid of the socket, for example, if the
1531 * listener is closing.
1532 */
1533 if (tcp->tcp_listener != NULL) {
1534 ASSERT(IPCL_IS_NONSTR(connp));
1535 msg = "tcp_close, close before accept";
1536
1537 /*
1538 * Unlink from the listener and drop the reference
1539 * put on it by the eager. tcp_closei_local will not
1540 * do it because tcp_tconnind_started is TRUE.
1541 */
1542 mutex_enter(&tcp->tcp_saved_listener->tcp_eager_lock);
1543 tcp_eager_unlink(tcp);
1544 mutex_exit(&tcp->tcp_saved_listener->tcp_eager_lock);
1545 CONN_DEC_REF(tcp->tcp_saved_listener->tcp_connp);
1546 break;
1547 }
1548
1549 /*
1550 * Transmit the FIN before detaching the tcp_t.
1551 * After tcp_detach returns this queue/perimeter
1552 * no longer owns the tcp_t thus others can modify it.
1553 */
1554 (void) tcp_xmit_end(tcp);
1555
1556 /*
1557 * If lingering on close then wait until the fin is acked,
1558 * the SO_LINGER time passes, or a reset is sent/received.
1559 */
1560 if (connp->conn_linger && connp->conn_lingertime > 0 &&
1561 !(tcp->tcp_fin_acked) &&
1562 tcp->tcp_state >= TCPS_ESTABLISHED) {
1563 if (tcp->tcp_closeflags & (FNDELAY|FNONBLOCK)) {
1564 tcp->tcp_client_errno = EWOULDBLOCK;
1565 } else if (tcp->tcp_client_errno == 0) {
1566
1567 ASSERT(tcp->tcp_linger_tid == 0);
1568
1569 /* conn_lingertime is in sec. */
1570 tcp->tcp_linger_tid = TCP_TIMER(tcp,
1571 tcp_close_linger_timeout,
1572 connp->conn_lingertime * MILLISEC);
1573
1574 /* tcp_close_linger_timeout will finish close */
1575 if (tcp->tcp_linger_tid == 0)
1576 tcp->tcp_client_errno = ENOSR;
1577 else
1578 return;
1579 }
1580
1581 /*
1582 * Check if we need to detach or just close
1583 * the instance.
1584 */
1585 if (tcp->tcp_state <= TCPS_LISTEN)
1586 break;
1587 }
1588
1589 /*
1590 * Make sure that no other thread will access the conn_rq of
1591 * this instance (through lookups etc.) as conn_rq will go
1592 * away shortly.
1593 */
1594 tcp_acceptor_hash_remove(tcp);
1595
1596 mutex_enter(&tcp->tcp_non_sq_lock);
1597 if (tcp->tcp_flow_stopped) {
1598 tcp_clrqfull(tcp);
1599 }
1600 mutex_exit(&tcp->tcp_non_sq_lock);
1601
1602 if (tcp->tcp_timer_tid != 0) {
1603 delta = TCP_TIMER_CANCEL(tcp, tcp->tcp_timer_tid);
1604 tcp->tcp_timer_tid = 0;
1605 }
1606 /*
1607 * Need to cancel those timers which will not be used when
1608 * TCP is detached. This has to be done before the conn_wq
1609 * is set to NULL.
1610 */
1611 tcp_timers_stop(tcp);
1612
1613 tcp->tcp_detached = B_TRUE;
1614 if (tcp->tcp_state == TCPS_TIME_WAIT) {
1615 tcp_time_wait_append(tcp);
1616 TCP_DBGSTAT(tcps, tcp_detach_time_wait);
1617 ASSERT(connp->conn_ref >=
1618 (IPCL_IS_NONSTR(connp) ? 2 : 3));
1619 goto finish;
1620 }
1621
1622 /*
1623 * If delta is zero the timer event wasn't executed and was
1624 * successfully canceled. In this case we need to restart it
1625 * with the minimal delta possible.
1626 */
1627 if (delta >= 0)
1628 tcp->tcp_timer_tid = TCP_TIMER(tcp, tcp_timer,
1629 delta ? delta : 1);
1630
1631 ASSERT(connp->conn_ref >= (IPCL_IS_NONSTR(connp) ? 2 : 3));
1632 goto finish;
1633 }
1634
1635 /* Detach did not complete. Still need to remove q from stream. */
1636 if (msg) {
1637 if (tcp->tcp_state == TCPS_ESTABLISHED ||
1638 tcp->tcp_state == TCPS_CLOSE_WAIT)
1639 TCPS_BUMP_MIB(tcps, tcpEstabResets);
1640 if (tcp->tcp_state == TCPS_SYN_SENT ||
1641 tcp->tcp_state == TCPS_SYN_RCVD)
1642 TCPS_BUMP_MIB(tcps, tcpAttemptFails);
1643 tcp_xmit_ctl(msg, tcp, tcp->tcp_snxt, 0, TH_RST);
1644 }
1645
1646 tcp_closei_local(tcp);
1647 CONN_DEC_REF(connp);
1648 ASSERT(connp->conn_ref >= (IPCL_IS_NONSTR(connp) ? 1 : 2));
1649
1650 finish:
1651 /*
1652 * Don't change the queues in the case of a listener that has
1653 * eagers in its q or q0. It could surprise the eagers.
1654 * Instead wait for the eagers outside the squeue.
1655 *
1656 * For non-STREAMS sockets tcp_wait_for_eagers implies that
1657 * we should delay the su_closed upcall until all eagers have
1658 * dropped their references.
1659 */
1660 if (!tcp->tcp_wait_for_eagers) {
1661 tcp->tcp_detached = B_TRUE;
1662 connp->conn_rq = NULL;
1663 connp->conn_wq = NULL;
1664
1665 /* non-STREAM socket, release the upper handle */
1666 if (IPCL_IS_NONSTR(connp)) {
1667 ASSERT(connp->conn_upper_handle != NULL);
1668 (*connp->conn_upcalls->su_closed)
1669 (connp->conn_upper_handle);
1670 connp->conn_upper_handle = NULL;
1671 connp->conn_upcalls = NULL;
1672 }
1673 }
1674
1675 /* Signal tcp_close() to finish closing. */
1676 mutex_enter(&tcp->tcp_closelock);
1677 tcp->tcp_closed = 1;
1678 cv_signal(&tcp->tcp_closecv);
1679 mutex_exit(&tcp->tcp_closelock);
1680 }
1681
1682 /* ARGSUSED */
1683 void
1684 tcp_shutdown_output(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1685 {
1686 conn_t *connp = (conn_t *)arg;
1687 tcp_t *tcp = connp->conn_tcp;
1688
1689 freemsg(mp);
1690
1691 if (tcp->tcp_fused)
1692 tcp_unfuse(tcp);
1693
1694 if (tcp_xmit_end(tcp) != 0) {
1695 /*
1696 * We were crossing FINs and got a reset from
1697 * the other side. Just ignore it.
1698 */
1699 if (connp->conn_debug) {
1700 (void) strlog(TCP_MOD_ID, 0, 1,
1701 SL_ERROR|SL_TRACE,
1702 "tcp_shutdown_output() out of state %s",
1703 tcp_display(tcp, NULL, DISP_ADDR_AND_PORT));
1704 }
1705 }
1706 }
1707
1708 #pragma inline(tcp_send_data)
1709
1710 void
1711 tcp_send_data(tcp_t *tcp, mblk_t *mp)
1712 {
1713 conn_t *connp = tcp->tcp_connp;
1714
1715 /*
1716 * Check here to avoid sending zero-copy message down to IP when
1717 * ZEROCOPY capability has turned off. We only need to deal with
1718 * the race condition between sockfs and the notification here.
1719 * Since we have tried to backoff the tcp_xmit_head when turning
1720 * zero-copy off and new messages in tcp_output(), we simply drop
1721 * the dup'ed packet here and let tcp retransmit, if tcp_xmit_zc_clean
1722 * is not true.
1723 */
1724 if (tcp->tcp_snd_zcopy_aware && !tcp->tcp_snd_zcopy_on &&
1725 !tcp->tcp_xmit_zc_clean) {
1726 ip_drop_output("TCP ZC was disabled but not clean", mp, NULL);
1727 freemsg(mp);
1728 return;
1729 }
1730
1731 DTRACE_TCP5(send, mblk_t *, NULL, ip_xmit_attr_t *, connp->conn_ixa,
1732 __dtrace_tcp_void_ip_t *, mp->b_rptr, tcp_t *, tcp,
1733 __dtrace_tcp_tcph_t *,
1734 &mp->b_rptr[connp->conn_ixa->ixa_ip_hdr_length]);
1735
1736 ASSERT(connp->conn_ixa->ixa_notify_cookie == connp->conn_tcp);
1737 (void) conn_ip_output(mp, connp->conn_ixa);
1738 }
1739
1740 /* ARGSUSED2 */
1741 void
1742 tcp_send_synack(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *dummy)
1743 {
1744 conn_t *econnp = (conn_t *)arg;
1745 tcp_t *tcp = econnp->conn_tcp;
1746 ip_xmit_attr_t *ixa = econnp->conn_ixa;
1747
1748 /* Guard against a RST having blown it away while on the squeue */
1749 if (tcp->tcp_state == TCPS_CLOSED) {
1750 freemsg(mp);
1751 return;
1752 }
1753
1754 /*
1755 * In the off-chance that the eager received and responded to
1756 * some other packet while the SYN|ACK was queued, we recalculate
1757 * the ixa_pktlen. It would be better to fix the SYN/accept
1758 * multithreading scheme to avoid this complexity.
1759 */
1760 ixa->ixa_pktlen = msgdsize(mp);
1761 (void) conn_ip_output(mp, ixa);
1762 }
1763
1764 /*
1765 * tcp_send() is called by tcp_wput_data() and returns one of the following:
1766 *
1767 * -1 = failed allocation.
1768 * 0 = We've either successfully sent data, or our usable send window is too
1769 * small and we'd rather wait until later before sending again.
1770 */
1771 static int
1772 tcp_send(tcp_t *tcp, const int mss, const int total_hdr_len,
1773 const int tcp_hdr_len, const int num_sack_blk, int *usable,
1774 uint32_t *snxt, int *tail_unsent, mblk_t **xmit_tail, mblk_t *local_time)
1775 {
1776 int num_lso_seg = 1;
1777 uint_t lso_usable;
1778 boolean_t do_lso_send = B_FALSE;
1779 tcp_stack_t *tcps = tcp->tcp_tcps;
1780 conn_t *connp = tcp->tcp_connp;
1781 ip_xmit_attr_t *ixa = connp->conn_ixa;
1782
1783 /*
1784 * Check LSO possibility. The value of tcp->tcp_lso indicates whether
1785 * the underlying connection is LSO capable. Will check whether having
1786 * enough available data to initiate LSO transmission in the for(){}
1787 * loops.
1788 */
1789 if (tcp->tcp_lso && (tcp->tcp_valid_bits & ~TCP_FSS_VALID) == 0)
1790 do_lso_send = B_TRUE;
1791
1792 for (;;) {
1793 struct datab *db;
1794 tcpha_t *tcpha;
1795 uint32_t sum;
1796 mblk_t *mp, *mp1;
1797 uchar_t *rptr;
1798 int len;
1799
1800 /*
1801 * Calculate the maximum payload length we can send at one
1802 * time.
1803 */
1804 if (do_lso_send) {
1805 /*
1806 * Determine whether or not it's possible to do LSO,
1807 * and if so, how much data we can send.
1808 */
1809 if ((*usable - 1) / mss >= 1) {
1810 lso_usable = MIN(tcp->tcp_lso_max, *usable);
1811 num_lso_seg = lso_usable / mss;
1812 if (lso_usable % mss) {
1813 num_lso_seg++;
1814 tcp->tcp_last_sent_len = (ushort_t)
1815 (lso_usable % mss);
1816 } else {
1817 tcp->tcp_last_sent_len = (ushort_t)mss;
1818 }
1819 } else {
1820 do_lso_send = B_FALSE;
1821 num_lso_seg = 1;
1822 lso_usable = mss;
1823 }
1824 }
1825
1826 ASSERT(num_lso_seg <= IP_MAXPACKET / mss + 1);
1827
1828 len = mss;
1829 if (len > *usable) {
1830 ASSERT(do_lso_send == B_FALSE);
1831
1832 len = *usable;
1833 if (len <= 0) {
1834 /* Terminate the loop */
1835 break; /* success; too small */
1836 }
1837 /*
1838 * Sender silly-window avoidance.
1839 * Ignore this if we are going to send a
1840 * zero window probe out.
1841 *
1842 * TODO: force data into microscopic window?
1843 * ==> (!pushed || (unsent > usable))
1844 */
1845 if (len < (tcp->tcp_max_swnd >> 1) &&
1846 (tcp->tcp_unsent - (*snxt - tcp->tcp_snxt)) > len &&
1847 !((tcp->tcp_valid_bits & TCP_URG_VALID) &&
1848 len == 1) && (! tcp->tcp_zero_win_probe)) {
1849 /*
1850 * If the retransmit timer is not running
1851 * we start it so that we will retransmit
1852 * in the case when the receiver has
1853 * decremented the window.
1854 */
1855 if (*snxt == tcp->tcp_snxt &&
1856 *snxt == tcp->tcp_suna) {
1857 /*
1858 * We are not supposed to send
1859 * anything. So let's wait a little
1860 * bit longer before breaking SWS
1861 * avoidance.
1862 *
1863 * What should the value be?
1864 * Suggestion: MAX(init rexmit time,
1865 * tcp->tcp_rto)
1866 */
1867 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
1868 }
1869 break; /* success; too small */
1870 }
1871 }
1872
1873 tcpha = tcp->tcp_tcpha;
1874
1875 /*
1876 * The reason to adjust len here is that we need to set flags
1877 * and calculate checksum.
1878 */
1879 if (do_lso_send)
1880 len = lso_usable;
1881
1882 *usable -= len; /* Approximate - can be adjusted later */
1883 if (*usable > 0)
1884 tcpha->tha_flags = TH_ACK;
1885 else
1886 tcpha->tha_flags = (TH_ACK | TH_PUSH);
1887
1888 /*
1889 * Prime pump for IP's checksumming on our behalf.
1890 * Include the adjustment for a source route if any.
1891 * In case of LSO, the partial pseudo-header checksum should
1892 * exclusive TCP length, so zero tha_sum before IP calculate
1893 * pseudo-header checksum for partial checksum offload.
1894 */
1895 if (do_lso_send) {
1896 sum = 0;
1897 } else {
1898 sum = len + tcp_hdr_len + connp->conn_sum;
1899 sum = (sum >> 16) + (sum & 0xFFFF);
1900 }
1901 tcpha->tha_sum = htons(sum);
1902 tcpha->tha_seq = htonl(*snxt);
1903
1904 /*
1905 * Branch off to tcp_xmit_mp() if any of the VALID bits is
1906 * set. For the case when TCP_FSS_VALID is the only valid
1907 * bit (normal active close), branch off only when we think
1908 * that the FIN flag needs to be set. Note for this case,
1909 * that (snxt + len) may not reflect the actual seg_len,
1910 * as len may be further reduced in tcp_xmit_mp(). If len
1911 * gets modified, we will end up here again.
1912 */
1913 if (tcp->tcp_valid_bits != 0 &&
1914 (tcp->tcp_valid_bits != TCP_FSS_VALID ||
1915 ((*snxt + len) == tcp->tcp_fss))) {
1916 uchar_t *prev_rptr;
1917 uint32_t prev_snxt = tcp->tcp_snxt;
1918
1919 if (*tail_unsent == 0) {
1920 ASSERT((*xmit_tail)->b_cont != NULL);
1921 *xmit_tail = (*xmit_tail)->b_cont;
1922 prev_rptr = (*xmit_tail)->b_rptr;
1923 *tail_unsent = (int)((*xmit_tail)->b_wptr -
1924 (*xmit_tail)->b_rptr);
1925 } else {
1926 prev_rptr = (*xmit_tail)->b_rptr;
1927 (*xmit_tail)->b_rptr = (*xmit_tail)->b_wptr -
1928 *tail_unsent;
1929 }
1930 mp = tcp_xmit_mp(tcp, *xmit_tail, len, NULL, NULL,
1931 *snxt, B_FALSE, (uint32_t *)&len, B_FALSE);
1932 /* Restore tcp_snxt so we get amount sent right. */
1933 tcp->tcp_snxt = prev_snxt;
1934 if (prev_rptr == (*xmit_tail)->b_rptr) {
1935 /*
1936 * If the previous timestamp is still in use,
1937 * don't stomp on it.
1938 */
1939 if ((*xmit_tail)->b_next == NULL) {
1940 (*xmit_tail)->b_prev = local_time;
1941 (*xmit_tail)->b_next =
1942 (mblk_t *)(uintptr_t)(*snxt);
1943 }
1944 } else
1945 (*xmit_tail)->b_rptr = prev_rptr;
1946
1947 if (mp == NULL) {
1948 return (-1);
1949 }
1950 mp1 = mp->b_cont;
1951
1952 if (len <= mss) /* LSO is unusable (!do_lso_send) */
1953 tcp->tcp_last_sent_len = (ushort_t)len;
1954 while (mp1->b_cont) {
1955 *xmit_tail = (*xmit_tail)->b_cont;
1956 (*xmit_tail)->b_prev = local_time;
1957 (*xmit_tail)->b_next =
1958 (mblk_t *)(uintptr_t)(*snxt);
1959 mp1 = mp1->b_cont;
1960 }
1961 *snxt += len;
1962 *tail_unsent = (*xmit_tail)->b_wptr - mp1->b_wptr;
1963 BUMP_LOCAL(tcp->tcp_obsegs);
1964 TCPS_BUMP_MIB(tcps, tcpOutDataSegs);
1965 TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, len);
1966 tcp_send_data(tcp, mp);
1967 continue;
1968 }
1969
1970 *snxt += len; /* Adjust later if we don't send all of len */
1971 TCPS_BUMP_MIB(tcps, tcpOutDataSegs);
1972 TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, len);
1973
1974 if (*tail_unsent) {
1975 /* Are the bytes above us in flight? */
1976 rptr = (*xmit_tail)->b_wptr - *tail_unsent;
1977 if (rptr != (*xmit_tail)->b_rptr) {
1978 *tail_unsent -= len;
1979 if (len <= mss) /* LSO is unusable */
1980 tcp->tcp_last_sent_len = (ushort_t)len;
1981 len += total_hdr_len;
1982 ixa->ixa_pktlen = len;
1983
1984 if (ixa->ixa_flags & IXAF_IS_IPV4) {
1985 tcp->tcp_ipha->ipha_length = htons(len);
1986 } else {
1987 tcp->tcp_ip6h->ip6_plen =
1988 htons(len - IPV6_HDR_LEN);
1989 }
1990
1991 mp = dupb(*xmit_tail);
1992 if (mp == NULL) {
1993 return (-1); /* out_of_mem */
1994 }
1995 mp->b_rptr = rptr;
1996 /*
1997 * If the old timestamp is no longer in use,
1998 * sample a new timestamp now.
1999 */
2000 if ((*xmit_tail)->b_next == NULL) {
2001 (*xmit_tail)->b_prev = local_time;
2002 (*xmit_tail)->b_next =
2003 (mblk_t *)(uintptr_t)(*snxt-len);
2004 }
2005 goto must_alloc;
2006 }
2007 } else {
2008 *xmit_tail = (*xmit_tail)->b_cont;
2009 ASSERT((uintptr_t)((*xmit_tail)->b_wptr -
2010 (*xmit_tail)->b_rptr) <= (uintptr_t)INT_MAX);
2011 *tail_unsent = (int)((*xmit_tail)->b_wptr -
2012 (*xmit_tail)->b_rptr);
2013 }
2014
2015 (*xmit_tail)->b_prev = local_time;
2016 (*xmit_tail)->b_next = (mblk_t *)(uintptr_t)(*snxt - len);
2017
2018 *tail_unsent -= len;
2019 if (len <= mss) /* LSO is unusable (!do_lso_send) */
2020 tcp->tcp_last_sent_len = (ushort_t)len;
2021
2022 len += total_hdr_len;
2023 ixa->ixa_pktlen = len;
2024
2025 if (ixa->ixa_flags & IXAF_IS_IPV4) {
2026 tcp->tcp_ipha->ipha_length = htons(len);
2027 } else {
2028 tcp->tcp_ip6h->ip6_plen = htons(len - IPV6_HDR_LEN);
2029 }
2030
2031 mp = dupb(*xmit_tail);
2032 if (mp == NULL) {
2033 return (-1); /* out_of_mem */
2034 }
2035
2036 len = total_hdr_len;
2037 /*
2038 * There are four reasons to allocate a new hdr mblk:
2039 * 1) The bytes above us are in use by another packet
2040 * 2) We don't have good alignment
2041 * 3) The mblk is being shared
2042 * 4) We don't have enough room for a header
2043 */
2044 rptr = mp->b_rptr - len;
2045 if (!OK_32PTR(rptr) ||
2046 ((db = mp->b_datap), db->db_ref != 2) ||
2047 rptr < db->db_base) {
2048 /* NOTE: we assume allocb returns an OK_32PTR */
2049
2050 must_alloc:;
2051 mp1 = allocb(connp->conn_ht_iphc_allocated +
2052 tcps->tcps_wroff_xtra, BPRI_MED);
2053 if (mp1 == NULL) {
2054 freemsg(mp);
2055 return (-1); /* out_of_mem */
2056 }
2057 mp1->b_cont = mp;
2058 mp = mp1;
2059 /* Leave room for Link Level header */
2060 len = total_hdr_len;
2061 rptr = &mp->b_rptr[tcps->tcps_wroff_xtra];
2062 mp->b_wptr = &rptr[len];
2063 }
2064
2065 /*
2066 * Fill in the header using the template header, and add
2067 * options such as time-stamp, ECN and/or SACK, as needed.
2068 */
2069 tcp_fill_header(tcp, rptr, num_sack_blk);
2070
2071 mp->b_rptr = rptr;
2072
2073 if (*tail_unsent) {
2074 int spill = *tail_unsent;
2075
2076 mp1 = mp->b_cont;
2077 if (mp1 == NULL)
2078 mp1 = mp;
2079
2080 /*
2081 * If we're a little short, tack on more mblks until
2082 * there is no more spillover.
2083 */
2084 while (spill < 0) {
2085 mblk_t *nmp;
2086 int nmpsz;
2087
2088 nmp = (*xmit_tail)->b_cont;
2089 nmpsz = MBLKL(nmp);
2090
2091 /*
2092 * Excess data in mblk; can we split it?
2093 * If LSO is enabled for the connection,
2094 * keep on splitting as this is a transient
2095 * send path.
2096 */
2097 if (!do_lso_send && (spill + nmpsz > 0)) {
2098 /*
2099 * Don't split if stream head was
2100 * told to break up larger writes
2101 * into smaller ones.
2102 */
2103 if (tcp->tcp_maxpsz_multiplier > 0)
2104 break;
2105
2106 /*
2107 * Next mblk is less than SMSS/2
2108 * rounded up to nearest 64-byte;
2109 * let it get sent as part of the
2110 * next segment.
2111 */
2112 if (tcp->tcp_localnet &&
2113 !tcp->tcp_cork &&
2114 (nmpsz < roundup((mss >> 1), 64)))
2115 break;
2116 }
2117
2118 *xmit_tail = nmp;
2119 ASSERT((uintptr_t)nmpsz <= (uintptr_t)INT_MAX);
2120 /* Stash for rtt use later */
2121 (*xmit_tail)->b_prev = local_time;
2122 (*xmit_tail)->b_next =
2123 (mblk_t *)(uintptr_t)(*snxt - len);
2124 mp1->b_cont = dupb(*xmit_tail);
2125 mp1 = mp1->b_cont;
2126
2127 spill += nmpsz;
2128 if (mp1 == NULL) {
2129 *tail_unsent = spill;
2130 freemsg(mp);
2131 return (-1); /* out_of_mem */
2132 }
2133 }
2134
2135 /* Trim back any surplus on the last mblk */
2136 if (spill >= 0) {
2137 mp1->b_wptr -= spill;
2138 *tail_unsent = spill;
2139 } else {
2140 /*
2141 * We did not send everything we could in
2142 * order to remain within the b_cont limit.
2143 */
2144 *usable -= spill;
2145 *snxt += spill;
2146 tcp->tcp_last_sent_len += spill;
2147 TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, spill);
2148 /*
2149 * Adjust the checksum
2150 */
2151 tcpha = (tcpha_t *)(rptr +
2152 ixa->ixa_ip_hdr_length);
2153 sum += spill;
2154 sum = (sum >> 16) + (sum & 0xFFFF);
2155 tcpha->tha_sum = htons(sum);
2156 if (connp->conn_ipversion == IPV4_VERSION) {
2157 sum = ntohs(
2158 ((ipha_t *)rptr)->ipha_length) +
2159 spill;
2160 ((ipha_t *)rptr)->ipha_length =
2161 htons(sum);
2162 } else {
2163 sum = ntohs(
2164 ((ip6_t *)rptr)->ip6_plen) +
2165 spill;
2166 ((ip6_t *)rptr)->ip6_plen =
2167 htons(sum);
2168 }
2169 ixa->ixa_pktlen += spill;
2170 *tail_unsent = 0;
2171 }
2172 }
2173 if (tcp->tcp_ip_forward_progress) {
2174 tcp->tcp_ip_forward_progress = B_FALSE;
2175 ixa->ixa_flags |= IXAF_REACH_CONF;
2176 } else {
2177 ixa->ixa_flags &= ~IXAF_REACH_CONF;
2178 }
2179
2180 if (do_lso_send) {
2181 /* Append LSO information to the mp. */
2182 lso_info_set(mp, mss, HW_LSO);
2183 ixa->ixa_fragsize = IP_MAXPACKET;
2184 ixa->ixa_extra_ident = num_lso_seg - 1;
2185
2186 DTRACE_PROBE2(tcp_send_lso, int, num_lso_seg,
2187 boolean_t, B_TRUE);
2188
2189 tcp_send_data(tcp, mp);
2190
2191 /*
2192 * Restore values of ixa_fragsize and ixa_extra_ident.
2193 */
2194 ixa->ixa_fragsize = ixa->ixa_pmtu;
2195 ixa->ixa_extra_ident = 0;
2196 tcp->tcp_obsegs += num_lso_seg;
2197 TCP_STAT(tcps, tcp_lso_times);
2198 TCP_STAT_UPDATE(tcps, tcp_lso_pkt_out, num_lso_seg);
2199 } else {
2200 /*
2201 * Make sure to clean up LSO information. Wherever a
2202 * new mp uses the prepended header room after dupb(),
2203 * lso_info_cleanup() should be called.
2204 */
2205 lso_info_cleanup(mp);
2206 tcp_send_data(tcp, mp);
2207 BUMP_LOCAL(tcp->tcp_obsegs);
2208 }
2209 }
2210
2211 return (0);
2212 }
2213
2214 /*
2215 * Initiate closedown sequence on an active connection. (May be called as
2216 * writer.) Return value zero for OK return, non-zero for error return.
2217 */
2218 static int
2219 tcp_xmit_end(tcp_t *tcp)
2220 {
2221 mblk_t *mp;
2222 tcp_stack_t *tcps = tcp->tcp_tcps;
2223 iulp_t uinfo;
2224 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
2225 conn_t *connp = tcp->tcp_connp;
2226
2227 if (tcp->tcp_state < TCPS_SYN_RCVD ||
2228 tcp->tcp_state > TCPS_CLOSE_WAIT) {
2229 /*
2230 * Invalid state, only states TCPS_SYN_RCVD,
2231 * TCPS_ESTABLISHED and TCPS_CLOSE_WAIT are valid
2232 */
2233 return (-1);
2234 }
2235
2236 tcp->tcp_fss = tcp->tcp_snxt + tcp->tcp_unsent;
2237 tcp->tcp_valid_bits |= TCP_FSS_VALID;
2238 /*
2239 * If there is nothing more unsent, send the FIN now.
2240 * Otherwise, it will go out with the last segment.
2241 */
2242 if (tcp->tcp_unsent == 0) {
2243 mp = tcp_xmit_mp(tcp, NULL, 0, NULL, NULL,
2244 tcp->tcp_fss, B_FALSE, NULL, B_FALSE);
2245
2246 if (mp) {
2247 tcp_send_data(tcp, mp);
2248 } else {
2249 /*
2250 * Couldn't allocate msg. Pretend we got it out.
2251 * Wait for rexmit timeout.
2252 */
2253 tcp->tcp_snxt = tcp->tcp_fss + 1;
2254 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
2255 }
2256
2257 /*
2258 * If needed, update tcp_rexmit_snxt as tcp_snxt is
2259 * changed.
2260 */
2261 if (tcp->tcp_rexmit && tcp->tcp_rexmit_nxt == tcp->tcp_fss) {
2262 tcp->tcp_rexmit_nxt = tcp->tcp_snxt;
2263 }
2264 } else {
2265 /*
2266 * If tcp->tcp_cork is set, then the data will not get sent,
2267 * so we have to check that and unset it first.
2268 */
2269 if (tcp->tcp_cork)
2270 tcp->tcp_cork = B_FALSE;
2271 tcp_wput_data(tcp, NULL, B_FALSE);
2272 }
2273
2274 /*
2275 * If TCP does not get enough samples of RTT or tcp_rtt_updates
2276 * is 0, don't update the cache.
2277 */
2278 if (tcps->tcps_rtt_updates == 0 ||
2279 tcp->tcp_rtt_update < tcps->tcps_rtt_updates)
2280 return (0);
2281
2282 /*
2283 * We do not have a good algorithm to update ssthresh at this time.
2284 * So don't do any update.
2285 */
2286 bzero(&uinfo, sizeof (uinfo));
2287 uinfo.iulp_rtt = NSEC2MSEC(tcp->tcp_rtt_sa);
2288 uinfo.iulp_rtt_sd = NSEC2MSEC(tcp->tcp_rtt_sd);
2289
2290 /*
2291 * Note that uinfo is kept for conn_faddr in the DCE. Could update even
2292 * if source routed but we don't.
2293 */
2294 if (connp->conn_ipversion == IPV4_VERSION) {
2295 if (connp->conn_faddr_v4 != tcp->tcp_ipha->ipha_dst) {
2296 return (0);
2297 }
2298 (void) dce_update_uinfo_v4(connp->conn_faddr_v4, &uinfo, ipst);
2299 } else {
2300 uint_t ifindex;
2301
2302 if (!(IN6_ARE_ADDR_EQUAL(&connp->conn_faddr_v6,
2303 &tcp->tcp_ip6h->ip6_dst))) {
2304 return (0);
2305 }
2306 ifindex = 0;
2307 if (IN6_IS_ADDR_LINKSCOPE(&connp->conn_faddr_v6)) {
2308 ip_xmit_attr_t *ixa = connp->conn_ixa;
2309
2310 /*
2311 * If we are going to create a DCE we'd better have
2312 * an ifindex
2313 */
2314 if (ixa->ixa_nce != NULL) {
2315 ifindex = ixa->ixa_nce->nce_common->ncec_ill->
2316 ill_phyint->phyint_ifindex;
2317 } else {
2318 return (0);
2319 }
2320 }
2321
2322 (void) dce_update_uinfo(&connp->conn_faddr_v6, ifindex, &uinfo,
2323 ipst);
2324 }
2325 return (0);
2326 }
2327
2328 /*
2329 * Send out a control packet on the tcp connection specified. This routine
2330 * is typically called where we need a simple ACK or RST generated.
2331 */
2332 void
2333 tcp_xmit_ctl(char *str, tcp_t *tcp, uint32_t seq, uint32_t ack, int ctl)
2334 {
2335 uchar_t *rptr;
2336 tcpha_t *tcpha;
2337 ipha_t *ipha = NULL;
2338 ip6_t *ip6h = NULL;
2339 uint32_t sum;
2340 int total_hdr_len;
2341 int ip_hdr_len;
2342 mblk_t *mp;
2343 tcp_stack_t *tcps = tcp->tcp_tcps;
2344 conn_t *connp = tcp->tcp_connp;
2345 ip_xmit_attr_t *ixa = connp->conn_ixa;
2346
2347 /*
2348 * Save sum for use in source route later.
2349 */
2350 sum = connp->conn_ht_ulp_len + connp->conn_sum;
2351 total_hdr_len = connp->conn_ht_iphc_len;
2352 ip_hdr_len = ixa->ixa_ip_hdr_length;
2353
2354 /* If a text string is passed in with the request, pass it to strlog. */
2355 if (str != NULL && connp->conn_debug) {
2356 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
2357 "tcp_xmit_ctl: '%s', seq 0x%x, ack 0x%x, ctl 0x%x",
2358 str, seq, ack, ctl);
2359 }
2360 mp = allocb(connp->conn_ht_iphc_allocated + tcps->tcps_wroff_xtra,
2361 BPRI_MED);
2362 if (mp == NULL) {
2363 return;
2364 }
2365 rptr = &mp->b_rptr[tcps->tcps_wroff_xtra];
2366 mp->b_rptr = rptr;
2367 mp->b_wptr = &rptr[total_hdr_len];
2368 bcopy(connp->conn_ht_iphc, rptr, total_hdr_len);
2369
2370 ixa->ixa_pktlen = total_hdr_len;
2371
2372 if (ixa->ixa_flags & IXAF_IS_IPV4) {
2373 ipha = (ipha_t *)rptr;
2374 ipha->ipha_length = htons(total_hdr_len);
2375 } else {
2376 ip6h = (ip6_t *)rptr;
2377 ip6h->ip6_plen = htons(total_hdr_len - IPV6_HDR_LEN);
2378 }
2379 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2380 tcpha->tha_flags = (uint8_t)ctl;
2381 if (ctl & TH_RST) {
2382 TCPS_BUMP_MIB(tcps, tcpOutRsts);
2383 TCPS_BUMP_MIB(tcps, tcpOutControl);
2384 /*
2385 * Don't send TSopt w/ TH_RST packets per RFC 1323.
2386 */
2387 if (tcp->tcp_snd_ts_ok &&
2388 tcp->tcp_state > TCPS_SYN_SENT) {
2389 mp->b_wptr = &rptr[total_hdr_len - TCPOPT_REAL_TS_LEN];
2390 *(mp->b_wptr) = TCPOPT_EOL;
2391
2392 ixa->ixa_pktlen = total_hdr_len - TCPOPT_REAL_TS_LEN;
2393
2394 if (connp->conn_ipversion == IPV4_VERSION) {
2395 ipha->ipha_length = htons(total_hdr_len -
2396 TCPOPT_REAL_TS_LEN);
2397 } else {
2398 ip6h->ip6_plen = htons(total_hdr_len -
2399 IPV6_HDR_LEN - TCPOPT_REAL_TS_LEN);
2400 }
2401 tcpha->tha_offset_and_reserved -= (3 << 4);
2402 sum -= TCPOPT_REAL_TS_LEN;
2403 }
2404 }
2405 if (ctl & TH_ACK) {
2406 if (tcp->tcp_snd_ts_ok) {
2407 uint32_t llbolt = (uint32_t)LBOLT_FASTPATH;
2408
2409 U32_TO_BE32(llbolt,
2410 (char *)tcpha + TCP_MIN_HEADER_LENGTH+4);
2411 U32_TO_BE32(tcp->tcp_ts_recent,
2412 (char *)tcpha + TCP_MIN_HEADER_LENGTH+8);
2413 }
2414
2415 /* Update the latest receive window size in TCP header. */
2416 tcpha->tha_win = htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
2417 /* Track what we sent to the peer */
2418 tcp->tcp_tcpha->tha_win = tcpha->tha_win;
2419 tcp->tcp_rack = ack;
2420 tcp->tcp_rack_cnt = 0;
2421 TCPS_BUMP_MIB(tcps, tcpOutAck);
2422 }
2423 BUMP_LOCAL(tcp->tcp_obsegs);
2424 tcpha->tha_seq = htonl(seq);
2425 tcpha->tha_ack = htonl(ack);
2426 /*
2427 * Include the adjustment for a source route if any.
2428 */
2429 sum = (sum >> 16) + (sum & 0xFFFF);
2430 tcpha->tha_sum = htons(sum);
2431 tcp_send_data(tcp, mp);
2432 }
2433
2434 /*
2435 * Generate a reset based on an inbound packet, connp is set by caller
2436 * when RST is in response to an unexpected inbound packet for which
2437 * there is active tcp state in the system.
2438 *
2439 * IPSEC NOTE : Try to send the reply with the same protection as it came
2440 * in. We have the ip_recv_attr_t which is reversed to form the ip_xmit_attr_t.
2441 * That way the packet will go out at the same level of protection as it
2442 * came in with.
2443 */
2444 static void
2445 tcp_xmit_early_reset(char *str, mblk_t *mp, uint32_t seq, uint32_t ack, int ctl,
2446 ip_recv_attr_t *ira, ip_stack_t *ipst, conn_t *connp)
2447 {
2448 ipha_t *ipha = NULL;
2449 ip6_t *ip6h = NULL;
2450 ushort_t len;
2451 tcpha_t *tcpha;
2452 int i;
2453 ipaddr_t v4addr;
2454 in6_addr_t v6addr;
2455 netstack_t *ns = ipst->ips_netstack;
2456 tcp_stack_t *tcps = ns->netstack_tcp;
2457 ip_xmit_attr_t ixas, *ixa;
2458 uint_t ip_hdr_len = ira->ira_ip_hdr_length;
2459 boolean_t need_refrele = B_FALSE; /* ixa_refrele(ixa) */
2460 ushort_t port;
2461
2462 if (!tcp_send_rst_chk(tcps)) {
2463 TCP_STAT(tcps, tcp_rst_unsent);
2464 freemsg(mp);
2465 return;
2466 }
2467
2468 /*
2469 * If connp != NULL we use conn_ixa to keep IP_NEXTHOP and other
2470 * options from the listener. In that case the caller must ensure that
2471 * we are running on the listener = connp squeue.
2472 *
2473 * We get a safe copy of conn_ixa so we don't need to restore anything
2474 * we or ip_output_simple might change in the ixa.
2475 */
2476 if (connp != NULL) {
2477 ASSERT(connp->conn_on_sqp);
2478
2479 ixa = conn_get_ixa_exclusive(connp);
2480 if (ixa == NULL) {
2481 TCP_STAT(tcps, tcp_rst_unsent);
2482 freemsg(mp);
2483 return;
2484 }
2485 need_refrele = B_TRUE;
2486 } else {
2487 bzero(&ixas, sizeof (ixas));
2488 ixa = &ixas;
2489 /*
2490 * IXAF_VERIFY_SOURCE is overkill since we know the
2491 * packet was for us.
2492 */
2493 ixa->ixa_flags |= IXAF_SET_ULP_CKSUM | IXAF_VERIFY_SOURCE;
2494 ixa->ixa_protocol = IPPROTO_TCP;
2495 ixa->ixa_zoneid = ira->ira_zoneid;
2496 ixa->ixa_ifindex = 0;
2497 ixa->ixa_ipst = ipst;
2498 ixa->ixa_cred = kcred;
2499 ixa->ixa_cpid = NOPID;
2500 }
2501
2502 if (str && tcps->tcps_dbg) {
2503 (void) strlog(TCP_MOD_ID, 0, 1, SL_TRACE,
2504 "tcp_xmit_early_reset: '%s', seq 0x%x, ack 0x%x, "
2505 "flags 0x%x",
2506 str, seq, ack, ctl);
2507 }
2508 if (mp->b_datap->db_ref != 1) {
2509 mblk_t *mp1 = copyb(mp);
2510 freemsg(mp);
2511 mp = mp1;
2512 if (mp == NULL)
2513 goto done;
2514 } else if (mp->b_cont) {
2515 freemsg(mp->b_cont);
2516 mp->b_cont = NULL;
2517 DB_CKSUMFLAGS(mp) = 0;
2518 }
2519 /*
2520 * We skip reversing source route here.
2521 * (for now we replace all IP options with EOL)
2522 */
2523 if (IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION) {
2524 ipha = (ipha_t *)mp->b_rptr;
2525 for (i = IP_SIMPLE_HDR_LENGTH; i < (int)ip_hdr_len; i++)
2526 mp->b_rptr[i] = IPOPT_EOL;
2527 /*
2528 * Make sure that src address isn't flagrantly invalid.
2529 * Not all broadcast address checking for the src address
2530 * is possible, since we don't know the netmask of the src
2531 * addr. No check for destination address is done, since
2532 * IP will not pass up a packet with a broadcast dest
2533 * address to TCP. Similar checks are done below for IPv6.
2534 */
2535 if (ipha->ipha_src == 0 || ipha->ipha_src == INADDR_BROADCAST ||
2536 CLASSD(ipha->ipha_src)) {
2537 BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsInDiscards);
2538 ip_drop_input("ipIfStatsInDiscards", mp, NULL);
2539 freemsg(mp);
2540 goto done;
2541 }
2542 } else {
2543 ip6h = (ip6_t *)mp->b_rptr;
2544
2545 if (IN6_IS_ADDR_UNSPECIFIED(&ip6h->ip6_src) ||
2546 IN6_IS_ADDR_MULTICAST(&ip6h->ip6_src)) {
2547 BUMP_MIB(&ipst->ips_ip6_mib, ipIfStatsInDiscards);
2548 ip_drop_input("ipIfStatsInDiscards", mp, NULL);
2549 freemsg(mp);
2550 goto done;
2551 }
2552
2553 /* Remove any extension headers assuming partial overlay */
2554 if (ip_hdr_len > IPV6_HDR_LEN) {
2555 uint8_t *to;
2556
2557 to = mp->b_rptr + ip_hdr_len - IPV6_HDR_LEN;
2558 ovbcopy(ip6h, to, IPV6_HDR_LEN);
2559 mp->b_rptr += ip_hdr_len - IPV6_HDR_LEN;
2560 ip_hdr_len = IPV6_HDR_LEN;
2561 ip6h = (ip6_t *)mp->b_rptr;
2562 ip6h->ip6_nxt = IPPROTO_TCP;
2563 }
2564 }
2565 tcpha = (tcpha_t *)&mp->b_rptr[ip_hdr_len];
2566 if (tcpha->tha_flags & TH_RST) {
2567 freemsg(mp);
2568 goto done;
2569 }
2570 tcpha->tha_offset_and_reserved = (5 << 4);
2571 len = ip_hdr_len + sizeof (tcpha_t);
2572 mp->b_wptr = &mp->b_rptr[len];
2573 if (IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION) {
2574 ipha->ipha_length = htons(len);
2575 /* Swap addresses */
2576 v4addr = ipha->ipha_src;
2577 ipha->ipha_src = ipha->ipha_dst;
2578 ipha->ipha_dst = v4addr;
2579 ipha->ipha_ident = 0;
2580 ipha->ipha_ttl = (uchar_t)tcps->tcps_ipv4_ttl;
2581 ixa->ixa_flags |= IXAF_IS_IPV4;
2582 ixa->ixa_ip_hdr_length = ip_hdr_len;
2583 } else {
2584 ip6h->ip6_plen = htons(len - IPV6_HDR_LEN);
2585 /* Swap addresses */
2586 v6addr = ip6h->ip6_src;
2587 ip6h->ip6_src = ip6h->ip6_dst;
2588 ip6h->ip6_dst = v6addr;
2589 ip6h->ip6_hops = (uchar_t)tcps->tcps_ipv6_hoplimit;
2590 ixa->ixa_flags &= ~IXAF_IS_IPV4;
2591
2592 if (IN6_IS_ADDR_LINKSCOPE(&ip6h->ip6_dst)) {
2593 ixa->ixa_flags |= IXAF_SCOPEID_SET;
2594 ixa->ixa_scopeid = ira->ira_ruifindex;
2595 }
2596 ixa->ixa_ip_hdr_length = IPV6_HDR_LEN;
2597 }
2598 ixa->ixa_pktlen = len;
2599
2600 /* Swap the ports */
2601 port = tcpha->tha_fport;
2602 tcpha->tha_fport = tcpha->tha_lport;
2603 tcpha->tha_lport = port;
2604
2605 tcpha->tha_ack = htonl(ack);
2606 tcpha->tha_seq = htonl(seq);
2607 tcpha->tha_win = 0;
2608 tcpha->tha_sum = htons(sizeof (tcpha_t));
2609 tcpha->tha_flags = (uint8_t)ctl;
2610 if (ctl & TH_RST) {
2611 if (ctl & TH_ACK) {
2612 /*
2613 * Probe connection rejection here.
2614 * tcp_xmit_listeners_reset() drops non-SYN segments
2615 * that do not specify TH_ACK in their flags without
2616 * calling this function. As a consequence, if this
2617 * function is called with a TH_RST|TH_ACK ctl argument,
2618 * it is being called in response to a SYN segment
2619 * and thus the tcp:::accept-refused probe point
2620 * is valid here.
2621 */
2622 DTRACE_TCP5(accept__refused, mblk_t *, NULL,
2623 void, NULL, void_ip_t *, mp->b_rptr, tcp_t *, NULL,
2624 tcph_t *, tcpha);
2625 }
2626 TCPS_BUMP_MIB(tcps, tcpOutRsts);
2627 TCPS_BUMP_MIB(tcps, tcpOutControl);
2628 }
2629
2630 /* Discard any old label */
2631 if (ixa->ixa_free_flags & IXA_FREE_TSL) {
2632 ASSERT(ixa->ixa_tsl != NULL);
2633 label_rele(ixa->ixa_tsl);
2634 ixa->ixa_free_flags &= ~IXA_FREE_TSL;
2635 }
2636 ixa->ixa_tsl = ira->ira_tsl; /* Behave as a multi-level responder */
2637
2638 if (ira->ira_flags & IRAF_IPSEC_SECURE) {
2639 /*
2640 * Apply IPsec based on how IPsec was applied to
2641 * the packet that caused the RST.
2642 */
2643 if (!ipsec_in_to_out(ira, ixa, mp, ipha, ip6h)) {
2644 BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
2645 /* Note: mp already consumed and ip_drop_packet done */
2646 goto done;
2647 }
2648 } else {
2649 /*
2650 * This is in clear. The RST message we are building
2651 * here should go out in clear, independent of our policy.
2652 */
2653 ixa->ixa_flags |= IXAF_NO_IPSEC;
2654 }
2655
2656 DTRACE_TCP5(send, mblk_t *, NULL, ip_xmit_attr_t *, ixa,
2657 __dtrace_tcp_void_ip_t *, mp->b_rptr, tcp_t *, NULL,
2658 __dtrace_tcp_tcph_t *, tcpha);
2659
2660 /*
2661 * NOTE: one might consider tracing a TCP packet here, but
2662 * this function has no active TCP state and no tcp structure
2663 * that has a trace buffer. If we traced here, we would have
2664 * to keep a local trace buffer in tcp_record_trace().
2665 */
2666
2667 (void) ip_output_simple(mp, ixa);
2668 done:
2669 ixa_cleanup(ixa);
2670 if (need_refrele) {
2671 ASSERT(ixa != &ixas);
2672 ixa_refrele(ixa);
2673 }
2674 }
2675
2676 /*
2677 * Generate a "no listener here" RST in response to an "unknown" segment.
2678 * connp is set by caller when RST is in response to an unexpected
2679 * inbound packet for which there is active tcp state in the system.
2680 * Note that we are reusing the incoming mp to construct the outgoing RST.
2681 */
2682 void
2683 tcp_xmit_listeners_reset(mblk_t *mp, ip_recv_attr_t *ira, ip_stack_t *ipst,
2684 conn_t *connp)
2685 {
2686 uchar_t *rptr;
2687 uint32_t seg_len;
2688 tcpha_t *tcpha;
2689 uint32_t seg_seq;
2690 uint32_t seg_ack;
2691 uint_t flags;
2692 ipha_t *ipha;
2693 ip6_t *ip6h;
2694 boolean_t policy_present;
2695 netstack_t *ns = ipst->ips_netstack;
2696 tcp_stack_t *tcps = ns->netstack_tcp;
2697 ipsec_stack_t *ipss = tcps->tcps_netstack->netstack_ipsec;
2698 uint_t ip_hdr_len = ira->ira_ip_hdr_length;
2699
2700 TCP_STAT(tcps, tcp_no_listener);
2701
2702 /*
2703 * DTrace this "unknown" segment as a tcp:::receive, as we did
2704 * just receive something that was TCP.
2705 */
2706 DTRACE_TCP5(receive, mblk_t *, NULL, ip_xmit_attr_t *, NULL,
2707 __dtrace_tcp_void_ip_t *, mp->b_rptr, tcp_t *, NULL,
2708 __dtrace_tcp_tcph_t *, &mp->b_rptr[ip_hdr_len]);
2709
2710 if (IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION) {
2711 policy_present = ipss->ipsec_inbound_v4_policy_present;
2712 ipha = (ipha_t *)mp->b_rptr;
2713 ip6h = NULL;
2714 } else {
2715 policy_present = ipss->ipsec_inbound_v6_policy_present;
2716 ipha = NULL;
2717 ip6h = (ip6_t *)mp->b_rptr;
2718 }
2719
2720 if (policy_present) {
2721 /*
2722 * The conn_t parameter is NULL because we already know
2723 * nobody's home.
2724 */
2725 mp = ipsec_check_global_policy(mp, (conn_t *)NULL, ipha, ip6h,
2726 ira, ns);
2727 if (mp == NULL)
2728 return;
2729 }
2730 if (is_system_labeled() && !tsol_can_reply_error(mp, ira)) {
2731 DTRACE_PROBE2(
2732 tx__ip__log__error__nolistener__tcp,
2733 char *, "Could not reply with RST to mp(1)",
2734 mblk_t *, mp);
2735 ip2dbg(("tcp_xmit_listeners_reset: not permitted to reply\n"));
2736 freemsg(mp);
2737 return;
2738 }
2739
2740 rptr = mp->b_rptr;
2741
2742 tcpha = (tcpha_t *)&rptr[ip_hdr_len];
2743 seg_seq = ntohl(tcpha->tha_seq);
2744 seg_ack = ntohl(tcpha->tha_ack);
2745 flags = tcpha->tha_flags;
2746
2747 seg_len = msgdsize(mp) - (TCP_HDR_LENGTH(tcpha) + ip_hdr_len);
2748 if (flags & TH_RST) {
2749 freemsg(mp);
2750 } else if (flags & TH_ACK) {
2751 tcp_xmit_early_reset("no tcp, reset", mp, seg_ack, 0, TH_RST,
2752 ira, ipst, connp);
2753 } else {
2754 if (flags & TH_SYN) {
2755 seg_len++;
2756 } else {
2757 /*
2758 * Here we violate the RFC. Note that a normal
2759 * TCP will never send a segment without the ACK
2760 * flag, except for RST or SYN segment. This
2761 * segment is neither. Just drop it on the
2762 * floor.
2763 */
2764 freemsg(mp);
2765 TCP_STAT(tcps, tcp_rst_unsent);
2766 return;
2767 }
2768
2769 tcp_xmit_early_reset("no tcp, reset/ack", mp, 0,
2770 seg_seq + seg_len, TH_RST | TH_ACK, ira, ipst, connp);
2771 }
2772 }
2773
2774 /*
2775 * Helper function for tcp_xmit_mp() in handling connection set up flag
2776 * options setting.
2777 */
2778 static void
2779 tcp_xmit_mp_aux_iss(tcp_t *tcp, conn_t *connp, tcpha_t *tcpha, mblk_t *mp,
2780 uint_t *flags)
2781 {
2782 uint32_t u1;
2783 uint8_t *wptr = mp->b_wptr;
2784 tcp_stack_t *tcps = tcp->tcp_tcps;
2785 boolean_t add_sack = B_FALSE;
2786
2787 /*
2788 * If TCP_ISS_VALID and the seq number is tcp_iss,
2789 * TCP can only be in SYN-SENT, SYN-RCVD or
2790 * FIN-WAIT-1 state. It can be FIN-WAIT-1 if
2791 * our SYN is not ack'ed but the app closes this
2792 * TCP connection.
2793 */
2794 ASSERT(tcp->tcp_state == TCPS_SYN_SENT ||
2795 tcp->tcp_state == TCPS_SYN_RCVD ||
2796 tcp->tcp_state == TCPS_FIN_WAIT_1);
2797
2798 /*
2799 * Tack on the MSS option. It is always needed
2800 * for both active and passive open.
2801 *
2802 * MSS option value should be interface MTU - MIN
2803 * TCP/IP header according to RFC 793 as it means
2804 * the maximum segment size TCP can receive. But
2805 * to get around some broken middle boxes/end hosts
2806 * out there, we allow the option value to be the
2807 * same as the MSS option size on the peer side.
2808 * In this way, the other side will not send
2809 * anything larger than they can receive.
2810 *
2811 * Note that for SYN_SENT state, the ndd param
2812 * tcp_use_smss_as_mss_opt has no effect as we
2813 * don't know the peer's MSS option value. So
2814 * the only case we need to take care of is in
2815 * SYN_RCVD state, which is done later.
2816 */
2817 wptr[0] = TCPOPT_MAXSEG;
2818 wptr[1] = TCPOPT_MAXSEG_LEN;
2819 wptr += 2;
2820 u1 = tcp->tcp_initial_pmtu - (connp->conn_ipversion == IPV4_VERSION ?
2821 IP_SIMPLE_HDR_LENGTH : IPV6_HDR_LEN) - TCP_MIN_HEADER_LENGTH;
2822 U16_TO_BE16(u1, wptr);
2823 wptr += 2;
2824
2825 /* Update the offset to cover the additional word */
2826 tcpha->tha_offset_and_reserved += (1 << 4);
2827
2828 switch (tcp->tcp_state) {
2829 case TCPS_SYN_SENT:
2830 *flags = TH_SYN;
2831
2832 if (tcp->tcp_snd_sack_ok)
2833 add_sack = B_TRUE;
2834
2835 if (tcp->tcp_snd_ts_ok) {
2836 uint32_t llbolt = (uint32_t)LBOLT_FASTPATH;
2837
2838 if (add_sack) {
2839 wptr[0] = TCPOPT_SACK_PERMITTED;
2840 wptr[1] = TCPOPT_SACK_OK_LEN;
2841 add_sack = B_FALSE;
2842 } else {
2843 wptr[0] = TCPOPT_NOP;
2844 wptr[1] = TCPOPT_NOP;
2845 }
2846 wptr[2] = TCPOPT_TSTAMP;
2847 wptr[3] = TCPOPT_TSTAMP_LEN;
2848 wptr += 4;
2849 U32_TO_BE32(llbolt, wptr);
2850 wptr += 4;
2851 ASSERT(tcp->tcp_ts_recent == 0);
2852 U32_TO_BE32(0L, wptr);
2853 wptr += 4;
2854 tcpha->tha_offset_and_reserved += (3 << 4);
2855 }
2856
2857 /*
2858 * Set up all the bits to tell other side
2859 * we are ECN capable.
2860 */
2861 if (tcp->tcp_ecn_ok)
2862 *flags |= (TH_ECE | TH_CWR);
2863
2864 break;
2865
2866 case TCPS_SYN_RCVD:
2867 *flags |= TH_SYN;
2868
2869 /*
2870 * Reset the MSS option value to be SMSS
2871 * We should probably add back the bytes
2872 * for timestamp option and IPsec. We
2873 * don't do that as this is a workaround
2874 * for broken middle boxes/end hosts, it
2875 * is better for us to be more cautious.
2876 * They may not take these things into
2877 * account in their SMSS calculation. Thus
2878 * the peer's calculated SMSS may be smaller
2879 * than what it can be. This should be OK.
2880 */
2881 if (tcps->tcps_use_smss_as_mss_opt) {
2882 u1 = tcp->tcp_mss;
2883 /*
2884 * Note that wptr points just past the MSS
2885 * option value.
2886 */
2887 U16_TO_BE16(u1, wptr - 2);
2888 }
2889
2890 /*
2891 * tcp_snd_ts_ok can only be set in TCPS_SYN_RCVD
2892 * when the peer also uses timestamps option. And
2893 * the TCP header template must have already been
2894 * updated to include the timestamps option.
2895 */
2896 if (tcp->tcp_snd_sack_ok) {
2897 if (tcp->tcp_snd_ts_ok) {
2898 uint8_t *tmp_wptr;
2899
2900 /*
2901 * Use the NOP in the header just
2902 * before timestamps opton.
2903 */
2904 tmp_wptr = (uint8_t *)tcpha +
2905 TCP_MIN_HEADER_LENGTH;
2906 ASSERT(tmp_wptr[0] == TCPOPT_NOP &&
2907 tmp_wptr[1] == TCPOPT_NOP);
2908 tmp_wptr[0] = TCPOPT_SACK_PERMITTED;
2909 tmp_wptr[1] = TCPOPT_SACK_OK_LEN;
2910 } else {
2911 add_sack = B_TRUE;
2912 }
2913 }
2914
2915
2916 /*
2917 * If the other side is ECN capable, reply
2918 * that we are also ECN capable.
2919 */
2920 if (tcp->tcp_ecn_ok)
2921 *flags |= TH_ECE;
2922 break;
2923
2924 default:
2925 /*
2926 * The above ASSERT() makes sure that this
2927 * must be FIN-WAIT-1 state. Our SYN has
2928 * not been ack'ed so retransmit it.
2929 */
2930 *flags |= TH_SYN;
2931 break;
2932 }
2933
2934 if (add_sack) {
2935 wptr[0] = TCPOPT_NOP;
2936 wptr[1] = TCPOPT_NOP;
2937 wptr[2] = TCPOPT_SACK_PERMITTED;
2938 wptr[3] = TCPOPT_SACK_OK_LEN;
2939 wptr += TCPOPT_REAL_SACK_OK_LEN;
2940 tcpha->tha_offset_and_reserved += (1 << 4);
2941 }
2942
2943 if (tcp->tcp_snd_ws_ok) {
2944 wptr[0] = TCPOPT_NOP;
2945 wptr[1] = TCPOPT_WSCALE;
2946 wptr[2] = TCPOPT_WS_LEN;
2947 wptr[3] = (uchar_t)tcp->tcp_rcv_ws;
2948 wptr += TCPOPT_REAL_WS_LEN;
2949 tcpha->tha_offset_and_reserved += (1 << 4);
2950 }
2951
2952 mp->b_wptr = wptr;
2953 u1 = (int)(mp->b_wptr - mp->b_rptr);
2954 /*
2955 * Get IP set to checksum on our behalf
2956 * Include the adjustment for a source route if any.
2957 */
2958 u1 += connp->conn_sum;
2959 u1 = (u1 >> 16) + (u1 & 0xFFFF);
2960 tcpha->tha_sum = htons(u1);
2961 TCPS_BUMP_MIB(tcps, tcpOutControl);
2962 }
2963
2964 /*
2965 * Helper function for tcp_xmit_mp() in handling connection tear down
2966 * flag setting and state changes.
2967 */
2968 static void
2969 tcp_xmit_mp_aux_fss(tcp_t *tcp, ip_xmit_attr_t *ixa, uint_t *flags)
2970 {
2971 if (!tcp->tcp_fin_acked) {
2972 *flags |= TH_FIN;
2973 TCPS_BUMP_MIB(tcp->tcp_tcps, tcpOutControl);
2974 }
2975 if (!tcp->tcp_fin_sent) {
2976 tcp->tcp_fin_sent = B_TRUE;
2977 switch (tcp->tcp_state) {
2978 case TCPS_SYN_RCVD:
2979 tcp->tcp_state = TCPS_FIN_WAIT_1;
2980 DTRACE_TCP6(state__change, void, NULL,
2981 ip_xmit_attr_t *, ixa, void, NULL,
2982 tcp_t *, tcp, void, NULL,
2983 int32_t, TCPS_SYN_RCVD);
2984 break;
2985 case TCPS_ESTABLISHED:
2986 tcp->tcp_state = TCPS_FIN_WAIT_1;
2987 DTRACE_TCP6(state__change, void, NULL,
2988 ip_xmit_attr_t *, ixa, void, NULL,
2989 tcp_t *, tcp, void, NULL,
2990 int32_t, TCPS_ESTABLISHED);
2991 break;
2992 case TCPS_CLOSE_WAIT:
2993 tcp->tcp_state = TCPS_LAST_ACK;
2994 DTRACE_TCP6(state__change, void, NULL,
2995 ip_xmit_attr_t *, ixa, void, NULL,
2996 tcp_t *, tcp, void, NULL,
2997 int32_t, TCPS_CLOSE_WAIT);
2998 break;
2999 }
3000 if (tcp->tcp_suna == tcp->tcp_snxt)
3001 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
3002 tcp->tcp_snxt = tcp->tcp_fss + 1;
3003 }
3004 }
3005
3006 /*
3007 * tcp_xmit_mp is called to return a pointer to an mblk chain complete with
3008 * ip and tcp header ready to pass down to IP. If the mp passed in is
3009 * non-NULL, then up to max_to_send bytes of data will be dup'ed off that
3010 * mblk. (If sendall is not set the dup'ing will stop at an mblk boundary
3011 * otherwise it will dup partial mblks.)
3012 * Otherwise, an appropriate ACK packet will be generated. This
3013 * routine is not usually called to send new data for the first time. It
3014 * is mostly called out of the timer for retransmits, and to generate ACKs.
3015 *
3016 * If offset is not NULL, the returned mblk chain's first mblk's b_rptr will
3017 * be adjusted by *offset. And after dupb(), the offset and the ending mblk
3018 * of the original mblk chain will be returned in *offset and *end_mp.
3019 */
3020 mblk_t *
3021 tcp_xmit_mp(tcp_t *tcp, mblk_t *mp, int32_t max_to_send, int32_t *offset,
3022 mblk_t **end_mp, uint32_t seq, boolean_t sendall, uint32_t *seg_len,
3023 boolean_t rexmit)
3024 {
3025 int data_length;
3026 int32_t off = 0;
3027 uint_t flags;
3028 mblk_t *mp1;
3029 mblk_t *mp2;
3030 uchar_t *rptr;
3031 tcpha_t *tcpha;
3032 int32_t num_sack_blk = 0;
3033 int32_t sack_opt_len = 0;
3034 tcp_stack_t *tcps = tcp->tcp_tcps;
3035 conn_t *connp = tcp->tcp_connp;
3036 ip_xmit_attr_t *ixa = connp->conn_ixa;
3037
3038 /* Allocate for our maximum TCP header + link-level */
3039 mp1 = allocb(connp->conn_ht_iphc_allocated + tcps->tcps_wroff_xtra,
3040 BPRI_MED);
3041 if (mp1 == NULL)
3042 return (NULL);
3043 data_length = 0;
3044
3045 /*
3046 * Note that tcp_mss has been adjusted to take into account the
3047 * timestamp option if applicable. Because SACK options do not
3048 * appear in every TCP segments and they are of variable lengths,
3049 * they cannot be included in tcp_mss. Thus we need to calculate
3050 * the actual segment length when we need to send a segment which
3051 * includes SACK options.
3052 */
3053 if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) {
3054 num_sack_blk = MIN(tcp->tcp_max_sack_blk,
3055 tcp->tcp_num_sack_blk);
3056 sack_opt_len = num_sack_blk * sizeof (sack_blk_t) +
3057 TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN;
3058 if (max_to_send + sack_opt_len > tcp->tcp_mss)
3059 max_to_send -= sack_opt_len;
3060 }
3061
3062 if (offset != NULL) {
3063 off = *offset;
3064 /* We use offset as an indicator that end_mp is not NULL. */
3065 *end_mp = NULL;
3066 }
3067 for (mp2 = mp1; mp && data_length != max_to_send; mp = mp->b_cont) {
3068 /* This could be faster with cooperation from downstream */
3069 if (mp2 != mp1 && !sendall &&
3070 data_length + (int)(mp->b_wptr - mp->b_rptr) >
3071 max_to_send)
3072 /*
3073 * Don't send the next mblk since the whole mblk
3074 * does not fit.
3075 */
3076 break;
3077 mp2->b_cont = dupb(mp);
3078 mp2 = mp2->b_cont;
3079 if (!mp2) {
3080 freemsg(mp1);
3081 return (NULL);
3082 }
3083 mp2->b_rptr += off;
3084 ASSERT((uintptr_t)(mp2->b_wptr - mp2->b_rptr) <=
3085 (uintptr_t)INT_MAX);
3086
3087 data_length += (int)(mp2->b_wptr - mp2->b_rptr);
3088 if (data_length > max_to_send) {
3089 mp2->b_wptr -= data_length - max_to_send;
3090 data_length = max_to_send;
3091 off = mp2->b_wptr - mp->b_rptr;
3092 break;
3093 } else {
3094 off = 0;
3095 }
3096 }
3097 if (offset != NULL) {
3098 *offset = off;
3099 *end_mp = mp;
3100 }
3101 if (seg_len != NULL) {
3102 *seg_len = data_length;
3103 }
3104
3105 /* Update the latest receive window size in TCP header. */
3106 tcp->tcp_tcpha->tha_win = htons(tcp->tcp_rwnd >> tcp->tcp_rcv_ws);
3107
3108 rptr = mp1->b_rptr + tcps->tcps_wroff_xtra;
3109 mp1->b_rptr = rptr;
3110 mp1->b_wptr = rptr + connp->conn_ht_iphc_len + sack_opt_len;
3111 bcopy(connp->conn_ht_iphc, rptr, connp->conn_ht_iphc_len);
3112 tcpha = (tcpha_t *)&rptr[ixa->ixa_ip_hdr_length];
3113 tcpha->tha_seq = htonl(seq);
3114
3115 /*
3116 * Use tcp_unsent to determine if the PUSH bit should be used assumes
3117 * that this function was called from tcp_wput_data. Thus, when called
3118 * to retransmit data the setting of the PUSH bit may appear some
3119 * what random in that it might get set when it should not. This
3120 * should not pose any performance issues.
3121 */
3122 if (data_length != 0 && (tcp->tcp_unsent == 0 ||
3123 tcp->tcp_unsent == data_length)) {
3124 flags = TH_ACK | TH_PUSH;
3125 } else {
3126 flags = TH_ACK;
3127 }
3128
3129 if (tcp->tcp_ecn_ok) {
3130 if (tcp->tcp_ecn_echo_on)
3131 flags |= TH_ECE;
3132
3133 /*
3134 * Only set ECT bit and ECN_CWR if a segment contains new data.
3135 * There is no TCP flow control for non-data segments, and
3136 * only data segment is transmitted reliably.
3137 */
3138 if (data_length > 0 && !rexmit) {
3139 TCP_SET_ECT(tcp, rptr);
3140 if (tcp->tcp_cwr && !tcp->tcp_ecn_cwr_sent) {
3141 flags |= TH_CWR;
3142 tcp->tcp_ecn_cwr_sent = B_TRUE;
3143 }
3144 }
3145 }
3146
3147 /* Check if there is any special processing needs to be done. */
3148 if (tcp->tcp_valid_bits) {
3149 uint32_t u1;
3150
3151 /* We don't allow having SYN and FIN in the same segment... */
3152 if ((tcp->tcp_valid_bits & TCP_ISS_VALID) &&
3153 seq == tcp->tcp_iss) {
3154 /* Need to do connection set up processing. */
3155 tcp_xmit_mp_aux_iss(tcp, connp, tcpha, mp1, &flags);
3156 } else if ((tcp->tcp_valid_bits & TCP_FSS_VALID) &&
3157 (seq + data_length) == tcp->tcp_fss) {
3158 /* Need to do connection tear down processing. */
3159 tcp_xmit_mp_aux_fss(tcp, ixa, &flags);
3160 }
3161
3162 /*
3163 * Need to do urgent pointer processing.
3164 *
3165 * Note the trick here. u1 is unsigned. When tcp_urg
3166 * is smaller than seq, u1 will become a very huge value.
3167 * So the comparison will fail. Also note that tcp_urp
3168 * should be positive, see RFC 793 page 17.
3169 */
3170 u1 = tcp->tcp_urg - seq + TCP_OLD_URP_INTERPRETATION;
3171 if ((tcp->tcp_valid_bits & TCP_URG_VALID) && u1 != 0 &&
3172 u1 < (uint32_t)(64 * 1024)) {
3173 flags |= TH_URG;
3174 TCPS_BUMP_MIB(tcps, tcpOutUrg);
3175 tcpha->tha_urp = htons(u1);
3176 }
3177 }
3178 tcpha->tha_flags = (uchar_t)flags;
3179 tcp->tcp_rack = tcp->tcp_rnxt;
3180 tcp->tcp_rack_cnt = 0;
3181
3182 /* Fill in the current value of timestamps option. */
3183 if (tcp->tcp_snd_ts_ok) {
3184 if (tcp->tcp_state != TCPS_SYN_SENT) {
3185 uint32_t llbolt = (uint32_t)LBOLT_FASTPATH;
3186
3187 U32_TO_BE32(llbolt,
3188 (char *)tcpha + TCP_MIN_HEADER_LENGTH+4);
3189 U32_TO_BE32(tcp->tcp_ts_recent,
3190 (char *)tcpha + TCP_MIN_HEADER_LENGTH+8);
3191 }
3192 }
3193
3194 /* Fill in the SACK blocks. */
3195 if (num_sack_blk > 0) {
3196 uchar_t *wptr = (uchar_t *)tcpha + connp->conn_ht_ulp_len;
3197 sack_blk_t *tmp;
3198 int32_t i;
3199
3200 wptr[0] = TCPOPT_NOP;
3201 wptr[1] = TCPOPT_NOP;
3202 wptr[2] = TCPOPT_SACK;
3203 wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk *
3204 sizeof (sack_blk_t);
3205 wptr += TCPOPT_REAL_SACK_LEN;
3206
3207 tmp = tcp->tcp_sack_list;
3208 for (i = 0; i < num_sack_blk; i++) {
3209 U32_TO_BE32(tmp[i].begin, wptr);
3210 wptr += sizeof (tcp_seq);
3211 U32_TO_BE32(tmp[i].end, wptr);
3212 wptr += sizeof (tcp_seq);
3213 }
3214 tcpha->tha_offset_and_reserved += ((num_sack_blk * 2 + 1) << 4);
3215 }
3216 ASSERT((uintptr_t)(mp1->b_wptr - rptr) <= (uintptr_t)INT_MAX);
3217 data_length += (int)(mp1->b_wptr - rptr);
3218
3219 ixa->ixa_pktlen = data_length;
3220
3221 if (ixa->ixa_flags & IXAF_IS_IPV4) {
3222 ((ipha_t *)rptr)->ipha_length = htons(data_length);
3223 } else {
3224 ip6_t *ip6 = (ip6_t *)rptr;
3225
3226 ip6->ip6_plen = htons(data_length - IPV6_HDR_LEN);
3227 }
3228
3229 /*
3230 * Prime pump for IP
3231 * Include the adjustment for a source route if any.
3232 */
3233 data_length -= ixa->ixa_ip_hdr_length;
3234 data_length += connp->conn_sum;
3235 data_length = (data_length >> 16) + (data_length & 0xFFFF);
3236 tcpha->tha_sum = htons(data_length);
3237 if (tcp->tcp_ip_forward_progress) {
3238 tcp->tcp_ip_forward_progress = B_FALSE;
3239 connp->conn_ixa->ixa_flags |= IXAF_REACH_CONF;
3240 } else {
3241 connp->conn_ixa->ixa_flags &= ~IXAF_REACH_CONF;
3242 }
3243 return (mp1);
3244 }
3245
3246 /*
3247 * If this routine returns B_TRUE, TCP can generate a RST in response
3248 * to a segment. If it returns B_FALSE, TCP should not respond.
3249 */
3250 static boolean_t
3251 tcp_send_rst_chk(tcp_stack_t *tcps)
3252 {
3253 int64_t now;
3254
3255 /*
3256 * TCP needs to protect itself from generating too many RSTs.
3257 * This can be a DoS attack by sending us random segments
3258 * soliciting RSTs.
3259 *
3260 * What we do here is to have a limit of tcp_rst_sent_rate RSTs
3261 * in each 1 second interval. In this way, TCP still generate
3262 * RSTs in normal cases but when under attack, the impact is
3263 * limited.
3264 */
3265 if (tcps->tcps_rst_sent_rate_enabled != 0) {
3266 now = ddi_get_lbolt64();
3267 if (TICK_TO_MSEC(now - tcps->tcps_last_rst_intrvl) >
3268 1*SECONDS) {
3269 tcps->tcps_last_rst_intrvl = now;
3270 tcps->tcps_rst_cnt = 1;
3271 } else if (++tcps->tcps_rst_cnt > tcps->tcps_rst_sent_rate) {
3272 return (B_FALSE);
3273 }
3274 }
3275 return (B_TRUE);
3276 }
3277
3278 /*
3279 * This function handles all retransmissions if SACK is enabled for this
3280 * connection. First it calculates how many segments can be retransmitted
3281 * based on tcp_pipe. Then it goes thru the notsack list to find eligible
3282 * segments. A segment is eligible if sack_cnt for that segment is greater
3283 * than or equal tcp_dupack_fast_retransmit. After it has retransmitted
3284 * all eligible segments, it checks to see if TCP can send some new segments
3285 * (fast recovery). If it can, set the appropriate flag for tcp_input_data().
3286 *
3287 * Parameters:
3288 * tcp_t *tcp: the tcp structure of the connection.
3289 * uint_t *flags: in return, appropriate value will be set for
3290 * tcp_input_data().
3291 */
3292 void
3293 tcp_sack_rexmit(tcp_t *tcp, uint_t *flags)
3294 {
3295 notsack_blk_t *notsack_blk;
3296 int32_t usable_swnd;
3297 int32_t mss;
3298 uint32_t seg_len;
3299 mblk_t *xmit_mp;
3300 tcp_stack_t *tcps = tcp->tcp_tcps;
3301
3302 ASSERT(tcp->tcp_notsack_list != NULL);
3303 ASSERT(tcp->tcp_rexmit == B_FALSE);
3304
3305 /* Defensive coding in case there is a bug... */
3306 if (tcp->tcp_notsack_list == NULL) {
3307 return;
3308 }
3309 notsack_blk = tcp->tcp_notsack_list;
3310 mss = tcp->tcp_mss;
3311
3312 /*
3313 * Limit the num of outstanding data in the network to be
3314 * tcp_cwnd_ssthresh, which is half of the original congestion wnd.
3315 */
3316 usable_swnd = tcp->tcp_cwnd_ssthresh - tcp->tcp_pipe;
3317
3318 /* At least retransmit 1 MSS of data. */
3319 if (usable_swnd <= 0) {
3320 usable_swnd = mss;
3321 }
3322
3323 /* Make sure no new RTT samples will be taken. */
3324 tcp->tcp_csuna = tcp->tcp_snxt;
3325
3326 notsack_blk = tcp->tcp_notsack_list;
3327 while (usable_swnd > 0) {
3328 mblk_t *snxt_mp, *tmp_mp;
3329 tcp_seq begin = tcp->tcp_sack_snxt;
3330 tcp_seq end;
3331 int32_t off;
3332
3333 for (; notsack_blk != NULL; notsack_blk = notsack_blk->next) {
3334 if (SEQ_GT(notsack_blk->end, begin) &&
3335 (notsack_blk->sack_cnt >=
3336 tcps->tcps_dupack_fast_retransmit)) {
3337 end = notsack_blk->end;
3338 if (SEQ_LT(begin, notsack_blk->begin)) {
3339 begin = notsack_blk->begin;
3340 }
3341 break;
3342 }
3343 }
3344 /*
3345 * All holes are filled. Manipulate tcp_cwnd to send more
3346 * if we can. Note that after the SACK recovery, tcp_cwnd is
3347 * set to tcp_cwnd_ssthresh.
3348 */
3349 if (notsack_blk == NULL) {
3350 usable_swnd = tcp->tcp_cwnd_ssthresh - tcp->tcp_pipe;
3351 if (usable_swnd <= 0 || tcp->tcp_unsent == 0) {
3352 tcp->tcp_cwnd = tcp->tcp_snxt - tcp->tcp_suna;
3353 ASSERT(tcp->tcp_cwnd > 0);
3354 return;
3355 } else {
3356 usable_swnd = usable_swnd / mss;
3357 tcp->tcp_cwnd = tcp->tcp_snxt - tcp->tcp_suna +
3358 MAX(usable_swnd * mss, mss);
3359 *flags |= TH_XMIT_NEEDED;
3360 return;
3361 }
3362 }
3363
3364 /*
3365 * Note that we may send more than usable_swnd allows here
3366 * because of round off, but no more than 1 MSS of data.
3367 */
3368 seg_len = end - begin;
3369 if (seg_len > mss)
3370 seg_len = mss;
3371 snxt_mp = tcp_get_seg_mp(tcp, begin, &off);
3372 ASSERT(snxt_mp != NULL);
3373 /* This should not happen. Defensive coding again... */
3374 if (snxt_mp == NULL) {
3375 return;
3376 }
3377
3378 xmit_mp = tcp_xmit_mp(tcp, snxt_mp, seg_len, &off,
3379 &tmp_mp, begin, B_TRUE, &seg_len, B_TRUE);
3380 if (xmit_mp == NULL)
3381 return;
3382
3383 usable_swnd -= seg_len;
3384 tcp->tcp_pipe += seg_len;
3385 tcp->tcp_sack_snxt = begin + seg_len;
3386
3387 tcp_send_data(tcp, xmit_mp);
3388
3389 /*
3390 * Update the send timestamp to avoid false retransmission.
3391 */
3392 snxt_mp->b_prev = (mblk_t *)(intptr_t)gethrtime();
3393
3394 TCPS_BUMP_MIB(tcps, tcpRetransSegs);
3395 TCPS_UPDATE_MIB(tcps, tcpRetransBytes, seg_len);
3396 TCPS_BUMP_MIB(tcps, tcpOutSackRetransSegs);
3397 /*
3398 * Update tcp_rexmit_max to extend this SACK recovery phase.
3399 * This happens when new data sent during fast recovery is
3400 * also lost. If TCP retransmits those new data, it needs
3401 * to extend SACK recover phase to avoid starting another
3402 * fast retransmit/recovery unnecessarily.
3403 */
3404 if (SEQ_GT(tcp->tcp_sack_snxt, tcp->tcp_rexmit_max)) {
3405 tcp->tcp_rexmit_max = tcp->tcp_sack_snxt;
3406 }
3407 }
3408 }
3409
3410 /*
3411 * tcp_ss_rexmit() is called to do slow start retransmission after a timeout
3412 * or ICMP errors.
3413 */
3414 void
3415 tcp_ss_rexmit(tcp_t *tcp)
3416 {
3417 uint32_t snxt;
3418 uint32_t smax;
3419 int32_t win;
3420 int32_t mss;
3421 int32_t off;
3422 mblk_t *snxt_mp;
3423 tcp_stack_t *tcps = tcp->tcp_tcps;
3424
3425 /*
3426 * Note that tcp_rexmit can be set even though TCP has retransmitted
3427 * all unack'ed segments.
3428 */
3429 if (SEQ_LT(tcp->tcp_rexmit_nxt, tcp->tcp_rexmit_max)) {
3430 smax = tcp->tcp_rexmit_max;
3431 snxt = tcp->tcp_rexmit_nxt;
3432 if (SEQ_LT(snxt, tcp->tcp_suna)) {
3433 snxt = tcp->tcp_suna;
3434 }
3435 win = MIN(tcp->tcp_cwnd, tcp->tcp_swnd);
3436 win -= snxt - tcp->tcp_suna;
3437 mss = tcp->tcp_mss;
3438 snxt_mp = tcp_get_seg_mp(tcp, snxt, &off);
3439
3440 while (SEQ_LT(snxt, smax) && (win > 0) && (snxt_mp != NULL)) {
3441 mblk_t *xmit_mp;
3442 mblk_t *old_snxt_mp = snxt_mp;
3443 uint32_t cnt = mss;
3444
3445 if (win < cnt) {
3446 cnt = win;
3447 }
3448 if (SEQ_GT(snxt + cnt, smax)) {
3449 cnt = smax - snxt;
3450 }
3451 xmit_mp = tcp_xmit_mp(tcp, snxt_mp, cnt, &off,
3452 &snxt_mp, snxt, B_TRUE, &cnt, B_TRUE);
3453 if (xmit_mp == NULL)
3454 return;
3455
3456 tcp_send_data(tcp, xmit_mp);
3457
3458 snxt += cnt;
3459 win -= cnt;
3460 /*
3461 * Update the send timestamp to avoid false
3462 * retransmission.
3463 */
3464 old_snxt_mp->b_prev = (mblk_t *)(intptr_t)gethrtime();
3465 TCPS_BUMP_MIB(tcps, tcpRetransSegs);
3466 TCPS_UPDATE_MIB(tcps, tcpRetransBytes, cnt);
3467
3468 tcp->tcp_rexmit_nxt = snxt;
3469 }
3470 /*
3471 * If we have transmitted all we have at the time
3472 * we started the retranmission, we can leave
3473 * the rest of the job to tcp_wput_data(). But we
3474 * need to check the send window first. If the
3475 * win is not 0, go on with tcp_wput_data().
3476 */
3477 if (SEQ_LT(snxt, smax) || win == 0) {
3478 return;
3479 }
3480 }
3481 /* Only call tcp_wput_data() if there is data to be sent. */
3482 if (tcp->tcp_unsent) {
3483 tcp_wput_data(tcp, NULL, B_FALSE);
3484 }
3485 }
3486
3487 /*
3488 * Do slow start retransmission after ICMP errors of PMTU changes.
3489 */
3490 void
3491 tcp_rexmit_after_error(tcp_t *tcp)
3492 {
3493 /*
3494 * All sent data has been acknowledged or no data left to send, just
3495 * to return.
3496 */
3497 if (!SEQ_LT(tcp->tcp_suna, tcp->tcp_snxt) ||
3498 (tcp->tcp_xmit_head == NULL))
3499 return;
3500
3501 if ((tcp->tcp_valid_bits & TCP_FSS_VALID) && (tcp->tcp_unsent == 0))
3502 tcp->tcp_rexmit_max = tcp->tcp_fss;
3503 else
3504 tcp->tcp_rexmit_max = tcp->tcp_snxt;
3505
3506 tcp->tcp_rexmit_nxt = tcp->tcp_suna;
3507 tcp->tcp_rexmit = B_TRUE;
3508 tcp->tcp_dupack_cnt = 0;
3509 tcp_ss_rexmit(tcp);
3510 }
3511
3512 /*
3513 * tcp_get_seg_mp() is called to get the pointer to a segment in the
3514 * send queue which starts at the given sequence number. If the given
3515 * sequence number is equal to last valid sequence number (tcp_snxt), the
3516 * returned mblk is the last valid mblk, and off is set to the length of
3517 * that mblk.
3518 *
3519 * send queue which starts at the given seq. no.
3520 *
3521 * Parameters:
3522 * tcp_t *tcp: the tcp instance pointer.
3523 * uint32_t seq: the starting seq. no of the requested segment.
3524 * int32_t *off: after the execution, *off will be the offset to
3525 * the returned mblk which points to the requested seq no.
3526 * It is the caller's responsibility to send in a non-null off.
3527 *
3528 * Return:
3529 * A mblk_t pointer pointing to the requested segment in send queue.
3530 */
3531 static mblk_t *
3532 tcp_get_seg_mp(tcp_t *tcp, uint32_t seq, int32_t *off)
3533 {
3534 int32_t cnt;
3535 mblk_t *mp;
3536
3537 /* Defensive coding. Make sure we don't send incorrect data. */
3538 if (SEQ_LT(seq, tcp->tcp_suna) || SEQ_GT(seq, tcp->tcp_snxt))
3539 return (NULL);
3540
3541 cnt = seq - tcp->tcp_suna;
3542 mp = tcp->tcp_xmit_head;
3543 while (cnt > 0 && mp != NULL) {
3544 cnt -= mp->b_wptr - mp->b_rptr;
3545 if (cnt <= 0) {
3546 cnt += mp->b_wptr - mp->b_rptr;
3547 break;
3548 }
3549 mp = mp->b_cont;
3550 }
3551 ASSERT(mp != NULL);
3552 *off = cnt;
3553 return (mp);
3554 }
3555
3556 /*
3557 * This routine adjusts next-to-send sequence number variables, in the
3558 * case where the reciever has shrunk it's window.
3559 */
3560 void
3561 tcp_update_xmit_tail(tcp_t *tcp, uint32_t snxt)
3562 {
3563 mblk_t *xmit_tail;
3564 int32_t offset;
3565
3566 tcp->tcp_snxt = snxt;
3567
3568 /* Get the mblk, and the offset in it, as per the shrunk window */
3569 xmit_tail = tcp_get_seg_mp(tcp, snxt, &offset);
3570 ASSERT(xmit_tail != NULL);
3571 tcp->tcp_xmit_tail = xmit_tail;
3572 tcp->tcp_xmit_tail_unsent = xmit_tail->b_wptr -
3573 xmit_tail->b_rptr - offset;
3574 }
3575
3576 /*
3577 * This handles the case when the receiver has shrunk its win. Per RFC 1122
3578 * if the receiver shrinks the window, i.e. moves the right window to the
3579 * left, the we should not send new data, but should retransmit normally the
3580 * old unacked data between suna and suna + swnd. We might has sent data
3581 * that is now outside the new window, pretend that we didn't send it.
3582 */
3583 static void
3584 tcp_process_shrunk_swnd(tcp_t *tcp, uint32_t shrunk_count)
3585 {
3586 uint32_t snxt = tcp->tcp_snxt;
3587
3588 ASSERT(shrunk_count > 0);
3589
3590 if (!tcp->tcp_is_wnd_shrnk) {
3591 tcp->tcp_snxt_shrunk = snxt;
3592 tcp->tcp_is_wnd_shrnk = B_TRUE;
3593 } else if (SEQ_GT(snxt, tcp->tcp_snxt_shrunk)) {
3594 tcp->tcp_snxt_shrunk = snxt;
3595 }
3596
3597 /* Pretend we didn't send the data outside the window */
3598 snxt -= shrunk_count;
3599
3600 /* Reset all the values per the now shrunk window */
3601 tcp_update_xmit_tail(tcp, snxt);
3602 tcp->tcp_unsent += shrunk_count;
3603
3604 /*
3605 * If the SACK option is set, delete the entire list of
3606 * notsack'ed blocks.
3607 */
3608 TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list, tcp);
3609
3610 if (tcp->tcp_suna == tcp->tcp_snxt && tcp->tcp_swnd == 0)
3611 /*
3612 * Make sure the timer is running so that we will probe a zero
3613 * window.
3614 */
3615 TCP_TIMER_RESTART(tcp, tcp->tcp_rto);
3616 }
3617
3618 /*
3619 * tcp_fill_header is called by tcp_send() to fill the outgoing TCP header
3620 * with the template header, as well as other options such as time-stamp,
3621 * ECN and/or SACK.
3622 */
3623 static void
3624 tcp_fill_header(tcp_t *tcp, uchar_t *rptr, int num_sack_blk)
3625 {
3626 tcpha_t *tcp_tmpl, *tcpha;
3627 uint32_t *dst, *src;
3628 int hdrlen;
3629 conn_t *connp = tcp->tcp_connp;
3630
3631 ASSERT(OK_32PTR(rptr));
3632
3633 /* Template header */
3634 tcp_tmpl = tcp->tcp_tcpha;
3635
3636 /* Header of outgoing packet */
3637 tcpha = (tcpha_t *)(rptr + connp->conn_ixa->ixa_ip_hdr_length);
3638
3639 /* dst and src are opaque 32-bit fields, used for copying */
3640 dst = (uint32_t *)rptr;
3641 src = (uint32_t *)connp->conn_ht_iphc;
3642 hdrlen = connp->conn_ht_iphc_len;
3643
3644 /* Fill time-stamp option if needed */
3645 if (tcp->tcp_snd_ts_ok) {
3646 U32_TO_BE32(LBOLT_FASTPATH,
3647 (char *)tcp_tmpl + TCP_MIN_HEADER_LENGTH + 4);
3648 U32_TO_BE32(tcp->tcp_ts_recent,
3649 (char *)tcp_tmpl + TCP_MIN_HEADER_LENGTH + 8);
3650 } else {
3651 ASSERT(connp->conn_ht_ulp_len == TCP_MIN_HEADER_LENGTH);
3652 }
3653
3654 /*
3655 * Copy the template header; is this really more efficient than
3656 * calling bcopy()? For simple IPv4/TCP, it may be the case,
3657 * but perhaps not for other scenarios.
3658 */
3659 dst[0] = src[0];
3660 dst[1] = src[1];
3661 dst[2] = src[2];
3662 dst[3] = src[3];
3663 dst[4] = src[4];
3664 dst[5] = src[5];
3665 dst[6] = src[6];
3666 dst[7] = src[7];
3667 dst[8] = src[8];
3668 dst[9] = src[9];
3669 if (hdrlen -= 40) {
3670 hdrlen >>= 2;
3671 dst += 10;
3672 src += 10;
3673 do {
3674 *dst++ = *src++;
3675 } while (--hdrlen);
3676 }
3677
3678 /*
3679 * Set the ECN info in the TCP header if it is not a zero
3680 * window probe. Zero window probe is only sent in
3681 * tcp_wput_data() and tcp_timer().
3682 */
3683 if (tcp->tcp_ecn_ok && !tcp->tcp_zero_win_probe) {
3684 TCP_SET_ECT(tcp, rptr);
3685
3686 if (tcp->tcp_ecn_echo_on)
3687 tcpha->tha_flags |= TH_ECE;
3688 if (tcp->tcp_cwr && !tcp->tcp_ecn_cwr_sent) {
3689 tcpha->tha_flags |= TH_CWR;
3690 tcp->tcp_ecn_cwr_sent = B_TRUE;
3691 }
3692 }
3693
3694 /* Fill in SACK options */
3695 if (num_sack_blk > 0) {
3696 uchar_t *wptr = rptr + connp->conn_ht_iphc_len;
3697 sack_blk_t *tmp;
3698 int32_t i;
3699
3700 wptr[0] = TCPOPT_NOP;
3701 wptr[1] = TCPOPT_NOP;
3702 wptr[2] = TCPOPT_SACK;
3703 wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk *
3704 sizeof (sack_blk_t);
3705 wptr += TCPOPT_REAL_SACK_LEN;
3706
3707 tmp = tcp->tcp_sack_list;
3708 for (i = 0; i < num_sack_blk; i++) {
3709 U32_TO_BE32(tmp[i].begin, wptr);
3710 wptr += sizeof (tcp_seq);
3711 U32_TO_BE32(tmp[i].end, wptr);
3712 wptr += sizeof (tcp_seq);
3713 }
3714 tcpha->tha_offset_and_reserved +=
3715 ((num_sack_blk * 2 + 1) << 4);
3716 }
3717 }