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 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25 #include <sys/types.h>
26 #include <sys/stream.h>
27 #include <sys/strsun.h>
28 #include <sys/strsubr.h>
29 #include <sys/debug.h>
30 #include <sys/sdt.h>
31 #include <sys/cmn_err.h>
32 #include <sys/tihdr.h>
33
34 #include <inet/common.h>
35 #include <inet/optcom.h>
36 #include <inet/ip.h>
37 #include <inet/ip_if.h>
38 #include <inet/ip_impl.h>
39 #include <inet/tcp.h>
40 #include <inet/tcp_impl.h>
41 #include <inet/ipsec_impl.h>
42 #include <inet/ipclassifier.h>
43 #include <inet/ipp_common.h>
44 #include <inet/ip_if.h>
45
46 /*
47 * This file implements TCP fusion - a protocol-less data path for TCP
48 * loopback connections. The fusion of two local TCP endpoints occurs
49 * at connection establishment time. Various conditions (see details
50 * in tcp_fuse()) need to be met for fusion to be successful. If it
51 * fails, we fall back to the regular TCP data path; if it succeeds,
52 * both endpoints proceed to use tcp_fuse_output() as the transmit path.
53 * tcp_fuse_output() enqueues application data directly onto the peer's
54 * receive queue; no protocol processing is involved.
55 *
56 * Sychronization is handled by squeue and the mutex tcp_non_sq_lock.
57 * One of the requirements for fusion to succeed is that both endpoints
58 * need to be using the same squeue. This ensures that neither side
59 * can disappear while the other side is still sending data. Flow
60 * control information is manipulated outside the squeue, so the
61 * tcp_non_sq_lock must be held when touching tcp_flow_stopped.
62 */
63
64 /*
65 * Setting this to false means we disable fusion altogether and
66 * loopback connections would go through the protocol paths.
67 */
68 boolean_t do_tcp_fusion = B_TRUE;
69
70 /*
71 * This routine gets called by the eager tcp upon changing state from
72 * SYN_RCVD to ESTABLISHED. It fuses a direct path between itself
73 * and the active connect tcp such that the regular tcp processings
74 * may be bypassed under allowable circumstances. Because the fusion
75 * requires both endpoints to be in the same squeue, it does not work
76 * for simultaneous active connects because there is no easy way to
77 * switch from one squeue to another once the connection is created.
78 * This is different from the eager tcp case where we assign it the
79 * same squeue as the one given to the active connect tcp during open.
80 */
81 void
82 tcp_fuse(tcp_t *tcp, uchar_t *iphdr, tcpha_t *tcpha)
83 {
84 conn_t *peer_connp, *connp = tcp->tcp_connp;
85 tcp_t *peer_tcp;
86 tcp_stack_t *tcps = tcp->tcp_tcps;
87 netstack_t *ns;
88 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
89
90 ASSERT(!tcp->tcp_fused);
91 ASSERT(tcp->tcp_loopback);
92 ASSERT(tcp->tcp_loopback_peer == NULL);
93 /*
94 * We need to inherit conn_rcvbuf of the listener tcp,
95 * but we can't really use tcp_listener since we get here after
96 * sending up T_CONN_IND and tcp_tli_accept() may be called
97 * independently, at which point tcp_listener is cleared;
98 * this is why we use tcp_saved_listener. The listener itself
99 * is guaranteed to be around until tcp_accept_finish() is called
100 * on this eager -- this won't happen until we're done since we're
101 * inside the eager's perimeter now.
102 */
103 ASSERT(tcp->tcp_saved_listener != NULL);
104 /*
105 * Lookup peer endpoint; search for the remote endpoint having
106 * the reversed address-port quadruplet in ESTABLISHED state,
107 * which is guaranteed to be unique in the system. Zone check
108 * is applied accordingly for loopback address, but not for
109 * local address since we want fusion to happen across Zones.
110 */
111 if (connp->conn_ipversion == IPV4_VERSION) {
112 peer_connp = ipcl_conn_tcp_lookup_reversed_ipv4(connp,
113 (ipha_t *)iphdr, tcpha, ipst);
114 } else {
115 peer_connp = ipcl_conn_tcp_lookup_reversed_ipv6(connp,
116 (ip6_t *)iphdr, tcpha, ipst);
117 }
118
119 /*
120 * We can only proceed if peer exists, resides in the same squeue
121 * as our conn and is not raw-socket. We also restrict fusion to
122 * endpoints of the same type (STREAMS or non-STREAMS). The squeue
123 * assignment of this eager tcp was done earlier at the time of SYN
124 * processing in ip_fanout_tcp{_v6}. Note that similar squeues by
125 * itself doesn't guarantee a safe condition to fuse, hence we perform
126 * additional tests below.
127 */
128 ASSERT(peer_connp == NULL || peer_connp != connp);
129 if (peer_connp == NULL || peer_connp->conn_sqp != connp->conn_sqp ||
130 !IPCL_IS_TCP(peer_connp) ||
131 IPCL_IS_NONSTR(connp) != IPCL_IS_NONSTR(peer_connp)) {
132 if (peer_connp != NULL) {
133 TCP_STAT(tcps, tcp_fusion_unqualified);
134 CONN_DEC_REF(peer_connp);
135 }
136 return;
137 }
138 peer_tcp = peer_connp->conn_tcp; /* active connect tcp */
139
140 ASSERT(peer_tcp != NULL && peer_tcp != tcp && !peer_tcp->tcp_fused);
141 ASSERT(peer_tcp->tcp_loopback_peer == NULL);
142 ASSERT(peer_connp->conn_sqp == connp->conn_sqp);
143
144 /*
145 * Due to IRE changes the peer and us might not agree on tcp_loopback.
146 * We bail in that case.
147 */
148 if (!peer_tcp->tcp_loopback) {
149 TCP_STAT(tcps, tcp_fusion_unqualified);
150 CONN_DEC_REF(peer_connp);
151 return;
152 }
153 /*
154 * Fuse the endpoints; we perform further checks against both
155 * tcp endpoints to ensure that a fusion is allowed to happen.
156 */
157 ns = tcps->tcps_netstack;
158 ipst = ns->netstack_ip;
159
160 if (!tcp->tcp_unfusable && !peer_tcp->tcp_unfusable &&
161 tcp->tcp_xmit_head == NULL && peer_tcp->tcp_xmit_head == NULL) {
162 mblk_t *mp;
163 queue_t *peer_rq = peer_connp->conn_rq;
164
165 ASSERT(!TCP_IS_DETACHED(peer_tcp));
166 ASSERT(tcp->tcp_fused_sigurg_mp == NULL);
167 ASSERT(peer_tcp->tcp_fused_sigurg_mp == NULL);
168
169 /*
170 * We need to drain data on both endpoints during unfuse.
171 * If we need to send up SIGURG at the time of draining,
172 * we want to be sure that an mblk is readily available.
173 * This is why we pre-allocate the M_PCSIG mblks for both
174 * endpoints which will only be used during/after unfuse.
175 * The mblk might already exist if we are doing a re-fuse.
176 */
177 if (!IPCL_IS_NONSTR(tcp->tcp_connp)) {
178 ASSERT(!IPCL_IS_NONSTR(peer_tcp->tcp_connp));
179
180 if (tcp->tcp_fused_sigurg_mp == NULL) {
181 if ((mp = allocb(1, BPRI_HI)) == NULL)
182 goto failed;
183 tcp->tcp_fused_sigurg_mp = mp;
184 }
185
186 if (peer_tcp->tcp_fused_sigurg_mp == NULL) {
187 if ((mp = allocb(1, BPRI_HI)) == NULL)
188 goto failed;
189 peer_tcp->tcp_fused_sigurg_mp = mp;
190 }
191
192 if ((mp = allocb(sizeof (struct stroptions),
193 BPRI_HI)) == NULL)
194 goto failed;
195 }
196
197 /* Fuse both endpoints */
198 peer_tcp->tcp_loopback_peer = tcp;
199 tcp->tcp_loopback_peer = peer_tcp;
200 peer_tcp->tcp_fused = tcp->tcp_fused = B_TRUE;
201
202 /*
203 * We never use regular tcp paths in fusion and should
204 * therefore clear tcp_unsent on both endpoints. Having
205 * them set to non-zero values means asking for trouble
206 * especially after unfuse, where we may end up sending
207 * through regular tcp paths which expect xmit_list and
208 * friends to be correctly setup.
209 */
210 peer_tcp->tcp_unsent = tcp->tcp_unsent = 0;
211
212 tcp_timers_stop(tcp);
213 tcp_timers_stop(peer_tcp);
214
215 /*
216 * Set receive buffer and max packet size for the
217 * active open tcp.
218 * eager's values will be set in tcp_accept_finish.
219 */
220 (void) tcp_rwnd_set(peer_tcp, peer_tcp->tcp_connp->conn_rcvbuf);
221
222 /*
223 * Set the write offset value to zero since we won't
224 * be needing any room for TCP/IP headers.
225 */
226 if (!IPCL_IS_NONSTR(peer_tcp->tcp_connp)) {
227 struct stroptions *stropt;
228
229 DB_TYPE(mp) = M_SETOPTS;
230 mp->b_wptr += sizeof (*stropt);
231
232 stropt = (struct stroptions *)mp->b_rptr;
233 stropt->so_flags = SO_WROFF | SO_MAXBLK;
234 stropt->so_wroff = 0;
235 stropt->so_maxblk = INFPSZ;
236
237 /* Send the options up */
238 putnext(peer_rq, mp);
239 } else {
240 struct sock_proto_props sopp;
241
242 /* The peer is a non-STREAMS end point */
243 ASSERT(IPCL_IS_TCP(peer_connp));
244
245 sopp.sopp_flags = SOCKOPT_WROFF | SOCKOPT_MAXBLK;
246 sopp.sopp_wroff = 0;
247 sopp.sopp_maxblk = INFPSZ;
248 (*peer_connp->conn_upcalls->su_set_proto_props)
249 (peer_connp->conn_upper_handle, &sopp);
250 }
251 } else {
252 TCP_STAT(tcps, tcp_fusion_unqualified);
253 }
254 CONN_DEC_REF(peer_connp);
255 return;
256
257 failed:
258 if (tcp->tcp_fused_sigurg_mp != NULL) {
259 freeb(tcp->tcp_fused_sigurg_mp);
260 tcp->tcp_fused_sigurg_mp = NULL;
261 }
262 if (peer_tcp->tcp_fused_sigurg_mp != NULL) {
263 freeb(peer_tcp->tcp_fused_sigurg_mp);
264 peer_tcp->tcp_fused_sigurg_mp = NULL;
265 }
266 CONN_DEC_REF(peer_connp);
267 }
268
269 /*
270 * Unfuse a previously-fused pair of tcp loopback endpoints.
271 */
272 void
273 tcp_unfuse(tcp_t *tcp)
274 {
275 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
276 tcp_stack_t *tcps = tcp->tcp_tcps;
277
278 ASSERT(tcp->tcp_fused && peer_tcp != NULL);
279 ASSERT(peer_tcp->tcp_fused && peer_tcp->tcp_loopback_peer == tcp);
280 ASSERT(tcp->tcp_connp->conn_sqp == peer_tcp->tcp_connp->conn_sqp);
281 ASSERT(tcp->tcp_unsent == 0 && peer_tcp->tcp_unsent == 0);
282
283 /*
284 * Cancel any pending push timers.
285 */
286 if (tcp->tcp_push_tid != 0) {
287 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
288 tcp->tcp_push_tid = 0;
289 }
290 if (peer_tcp->tcp_push_tid != 0) {
291 (void) TCP_TIMER_CANCEL(peer_tcp, peer_tcp->tcp_push_tid);
292 peer_tcp->tcp_push_tid = 0;
293 }
294
295 /*
296 * Drain any pending data; Note that in case of a detached tcp, the
297 * draining will happen later after the tcp is unfused. For non-
298 * urgent data, this can be handled by the regular tcp_rcv_drain().
299 * If we have urgent data sitting in the receive list, we will
300 * need to send up a SIGURG signal first before draining the data.
301 * All of these will be handled by the code in tcp_fuse_rcv_drain()
302 * when called from tcp_rcv_drain().
303 */
304 if (!TCP_IS_DETACHED(tcp)) {
305 (void) tcp_fuse_rcv_drain(tcp->tcp_connp->conn_rq, tcp,
306 &tcp->tcp_fused_sigurg_mp);
307 }
308 if (!TCP_IS_DETACHED(peer_tcp)) {
309 (void) tcp_fuse_rcv_drain(peer_tcp->tcp_connp->conn_rq,
310 peer_tcp, &peer_tcp->tcp_fused_sigurg_mp);
311 }
312
313 /* Lift up any flow-control conditions */
314 mutex_enter(&tcp->tcp_non_sq_lock);
315 if (tcp->tcp_flow_stopped) {
316 tcp_clrqfull(tcp);
317 TCP_STAT(tcps, tcp_fusion_backenabled);
318 }
319 mutex_exit(&tcp->tcp_non_sq_lock);
320
321 mutex_enter(&peer_tcp->tcp_non_sq_lock);
322 if (peer_tcp->tcp_flow_stopped) {
323 tcp_clrqfull(peer_tcp);
324 TCP_STAT(tcps, tcp_fusion_backenabled);
325 }
326 mutex_exit(&peer_tcp->tcp_non_sq_lock);
327
328 /*
329 * Update tha_seq and tha_ack in the header template
330 */
331 tcp->tcp_tcpha->tha_seq = htonl(tcp->tcp_snxt);
332 tcp->tcp_tcpha->tha_ack = htonl(tcp->tcp_rnxt);
333 peer_tcp->tcp_tcpha->tha_seq = htonl(peer_tcp->tcp_snxt);
334 peer_tcp->tcp_tcpha->tha_ack = htonl(peer_tcp->tcp_rnxt);
335
336 /* Unfuse the endpoints */
337 peer_tcp->tcp_fused = tcp->tcp_fused = B_FALSE;
338 peer_tcp->tcp_loopback_peer = tcp->tcp_loopback_peer = NULL;
339 }
340
341 /*
342 * Fusion output routine used to handle urgent data sent by STREAMS based
343 * endpoints. This routine is called by tcp_fuse_output() for handling
344 * non-M_DATA mblks.
345 */
346 void
347 tcp_fuse_output_urg(tcp_t *tcp, mblk_t *mp)
348 {
349 mblk_t *mp1;
350 struct T_exdata_ind *tei;
351 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
352 mblk_t *head, *prev_head = NULL;
353 tcp_stack_t *tcps = tcp->tcp_tcps;
354
355 ASSERT(tcp->tcp_fused);
356 ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
357 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
358 ASSERT(DB_TYPE(mp) == M_PROTO || DB_TYPE(mp) == M_PCPROTO);
359 ASSERT(mp->b_cont != NULL && DB_TYPE(mp->b_cont) == M_DATA);
360 ASSERT(MBLKL(mp) >= sizeof (*tei) && MBLKL(mp->b_cont) > 0);
361
362 /*
363 * Urgent data arrives in the form of T_EXDATA_REQ from above.
364 * Each occurence denotes a new urgent pointer. For each new
365 * urgent pointer we signal (SIGURG) the receiving app to indicate
366 * that it needs to go into urgent mode. This is similar to the
367 * urgent data handling in the regular tcp. We don't need to keep
368 * track of where the urgent pointer is, because each T_EXDATA_REQ
369 * "advances" the urgent pointer for us.
370 *
371 * The actual urgent data carried by T_EXDATA_REQ is then prepended
372 * by a T_EXDATA_IND before being enqueued behind any existing data
373 * destined for the receiving app. There is only a single urgent
374 * pointer (out-of-band mark) for a given tcp. If the new urgent
375 * data arrives before the receiving app reads some existing urgent
376 * data, the previous marker is lost. This behavior is emulated
377 * accordingly below, by removing any existing T_EXDATA_IND messages
378 * and essentially converting old urgent data into non-urgent.
379 */
380 ASSERT(tcp->tcp_valid_bits & TCP_URG_VALID);
381 /* Let sender get out of urgent mode */
382 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
383
384 /*
385 * This flag indicates that a signal needs to be sent up.
386 * This flag will only get cleared once SIGURG is delivered and
387 * is not affected by the tcp_fused flag -- delivery will still
388 * happen even after an endpoint is unfused, to handle the case
389 * where the sending endpoint immediately closes/unfuses after
390 * sending urgent data and the accept is not yet finished.
391 */
392 peer_tcp->tcp_fused_sigurg = B_TRUE;
393
394 /* Reuse T_EXDATA_REQ mblk for T_EXDATA_IND */
395 DB_TYPE(mp) = M_PROTO;
396 tei = (struct T_exdata_ind *)mp->b_rptr;
397 tei->PRIM_type = T_EXDATA_IND;
398 tei->MORE_flag = 0;
399 mp->b_wptr = (uchar_t *)&tei[1];
400
401 TCP_STAT(tcps, tcp_fusion_urg);
402 TCPS_BUMP_MIB(tcps, tcpOutUrg);
403
404 head = peer_tcp->tcp_rcv_list;
405 while (head != NULL) {
406 /*
407 * Remove existing T_EXDATA_IND, keep the data which follows
408 * it and relink our list. Note that we don't modify the
409 * tcp_rcv_last_tail since it never points to T_EXDATA_IND.
410 */
411 if (DB_TYPE(head) != M_DATA) {
412 mp1 = head;
413
414 ASSERT(DB_TYPE(mp1->b_cont) == M_DATA);
415 head = mp1->b_cont;
416 mp1->b_cont = NULL;
417 head->b_next = mp1->b_next;
418 mp1->b_next = NULL;
419 if (prev_head != NULL)
420 prev_head->b_next = head;
421 if (peer_tcp->tcp_rcv_list == mp1)
422 peer_tcp->tcp_rcv_list = head;
423 if (peer_tcp->tcp_rcv_last_head == mp1)
424 peer_tcp->tcp_rcv_last_head = head;
425 freeb(mp1);
426 }
427 prev_head = head;
428 head = head->b_next;
429 }
430 }
431
432 /*
433 * Fusion output routine, called by tcp_output() and tcp_wput_proto().
434 * If we are modifying any member that can be changed outside the squeue,
435 * like tcp_flow_stopped, we need to take tcp_non_sq_lock.
436 */
437 boolean_t
438 tcp_fuse_output(tcp_t *tcp, mblk_t *mp, uint32_t send_size)
439 {
440 conn_t *connp = tcp->tcp_connp;
441 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
442 conn_t *peer_connp = peer_tcp->tcp_connp;
443 boolean_t flow_stopped, peer_data_queued = B_FALSE;
444 boolean_t urgent = (DB_TYPE(mp) != M_DATA);
445 boolean_t push = B_TRUE;
446 mblk_t *mp1 = mp;
447 uint_t ip_hdr_len;
448 uint32_t recv_size = send_size;
449 tcp_stack_t *tcps = tcp->tcp_tcps;
450 netstack_t *ns = tcps->tcps_netstack;
451 ip_stack_t *ipst = ns->netstack_ip;
452 ipsec_stack_t *ipss = ns->netstack_ipsec;
453 iaflags_t ixaflags = connp->conn_ixa->ixa_flags;
454 boolean_t do_ipsec, hooks_out, hooks_in, ipobs_enabled;
455
456 ASSERT(tcp->tcp_fused);
457 ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
458 ASSERT(connp->conn_sqp == peer_connp->conn_sqp);
459 ASSERT(DB_TYPE(mp) == M_DATA || DB_TYPE(mp) == M_PROTO ||
460 DB_TYPE(mp) == M_PCPROTO);
461
462 if (send_size == 0) {
463 freemsg(mp);
464 return (B_TRUE);
465 }
466
467 /*
468 * Handle urgent data; we either send up SIGURG to the peer now
469 * or do it later when we drain, in case the peer is detached
470 * or if we're short of memory for M_PCSIG mblk.
471 */
472 if (urgent) {
473 tcp_fuse_output_urg(tcp, mp);
474
475 mp1 = mp->b_cont;
476 }
477
478 /*
479 * Check that we are still using an IRE_LOCAL or IRE_LOOPBACK before
480 * further processes.
481 */
482 if (!ip_output_verify_local(connp->conn_ixa))
483 goto unfuse;
484
485 /*
486 * Build IP and TCP header in case we have something that needs the
487 * headers. Those cases are:
488 * 1. IPsec
489 * 2. IPobs
490 * 3. FW_HOOKS
491 *
492 * If tcp_xmit_mp() fails to dupb() the message, unfuse the connection
493 * and back to regular path.
494 */
495 if (ixaflags & IXAF_IS_IPV4) {
496 do_ipsec = (ixaflags & IXAF_IPSEC_SECURE) ||
497 CONN_INBOUND_POLICY_PRESENT(peer_connp, ipss);
498
499 hooks_out = HOOKS4_INTERESTED_LOOPBACK_OUT(ipst);
500 hooks_in = HOOKS4_INTERESTED_LOOPBACK_IN(ipst);
501 ipobs_enabled = (ipst->ips_ip4_observe.he_interested != 0);
502 } else {
503 do_ipsec = (ixaflags & IXAF_IPSEC_SECURE) ||
504 CONN_INBOUND_POLICY_PRESENT_V6(peer_connp, ipss);
505
506 hooks_out = HOOKS6_INTERESTED_LOOPBACK_OUT(ipst);
507 hooks_in = HOOKS6_INTERESTED_LOOPBACK_IN(ipst);
508 ipobs_enabled = (ipst->ips_ip6_observe.he_interested != 0);
509 }
510
511 /* We do logical 'or' for efficiency */
512 if (ipobs_enabled | do_ipsec | hooks_in | hooks_out) {
513 if ((mp1 = tcp_xmit_mp(tcp, mp1, tcp->tcp_mss, NULL, NULL,
514 tcp->tcp_snxt, B_TRUE, NULL, B_FALSE)) == NULL)
515 /* If tcp_xmit_mp fails, use regular path */
516 goto unfuse;
517
518 /*
519 * Leave all IP relevant processes to ip_output_process_local(),
520 * which handles IPsec, IPobs, and FW_HOOKS.
521 */
522 mp1 = ip_output_process_local(mp1, connp->conn_ixa, hooks_out,
523 hooks_in, do_ipsec ? peer_connp : NULL);
524
525 /* If the message is dropped for any reason. */
526 if (mp1 == NULL)
527 goto unfuse;
528
529 /*
530 * Data length might have been changed by FW_HOOKS.
531 * We assume that the first mblk contains the TCP/IP headers.
532 */
533 if (hooks_in || hooks_out) {
534 tcpha_t *tcpha;
535
536 ip_hdr_len = (ixaflags & IXAF_IS_IPV4) ?
537 IPH_HDR_LENGTH((ipha_t *)mp1->b_rptr) :
538 ip_hdr_length_v6(mp1, (ip6_t *)mp1->b_rptr);
539
540 tcpha = (tcpha_t *)&mp1->b_rptr[ip_hdr_len];
541 ASSERT((uchar_t *)tcpha + sizeof (tcpha_t) <=
542 mp1->b_wptr);
543 recv_size += htonl(tcpha->tha_seq) - tcp->tcp_snxt;
544
545 }
546
547 /*
548 * The message duplicated by tcp_xmit_mp is freed.
549 * Note: the original message passed in remains unchanged.
550 */
551 freemsg(mp1);
552 }
553
554 /*
555 * Enqueue data into the peer's receive list; we may or may not
556 * drain the contents depending on the conditions below.
557 *
558 * For non-STREAMS sockets we normally queue data directly in the
559 * socket by calling the su_recv upcall. However, if the peer is
560 * detached we use tcp_rcv_enqueue() instead. Queued data will be
561 * drained when the accept completes (in tcp_accept_finish()).
562 */
563 if (IPCL_IS_NONSTR(peer_connp) &&
564 !TCP_IS_DETACHED(peer_tcp)) {
565 int error;
566 int flags = 0;
567
568 if ((tcp->tcp_valid_bits & TCP_URG_VALID) &&
569 (tcp->tcp_urg == tcp->tcp_snxt)) {
570 flags = MSG_OOB;
571 (*peer_connp->conn_upcalls->su_signal_oob)
572 (peer_connp->conn_upper_handle, 0);
573 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
574 }
575 if ((*peer_connp->conn_upcalls->su_recv)(
576 peer_connp->conn_upper_handle, mp, recv_size,
577 flags, &error, &push) < 0) {
578 ASSERT(error != EOPNOTSUPP);
579 peer_data_queued = B_TRUE;
580 }
581 } else {
582 if (IPCL_IS_NONSTR(peer_connp) &&
583 (tcp->tcp_valid_bits & TCP_URG_VALID) &&
584 (tcp->tcp_urg == tcp->tcp_snxt)) {
585 /*
586 * Can not deal with urgent pointers
587 * that arrive before the connection has been
588 * accept()ed.
589 */
590 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
591 freemsg(mp);
592 return (B_TRUE);
593 }
594
595 tcp_rcv_enqueue(peer_tcp, mp, recv_size,
596 tcp->tcp_connp->conn_cred);
597
598 /* In case it wrapped around and also to keep it constant */
599 peer_tcp->tcp_rwnd += recv_size;
600 }
601
602 /*
603 * Exercise flow-control when needed; we will get back-enabled
604 * in either tcp_accept_finish(), tcp_unfuse(), or when data is
605 * consumed. If peer endpoint is detached, we emulate streams flow
606 * control by checking the peer's queue size and high water mark;
607 * otherwise we simply use canputnext() to decide if we need to stop
608 * our flow.
609 *
610 * Since we are accessing our tcp_flow_stopped and might modify it,
611 * we need to take tcp->tcp_non_sq_lock.
612 */
613 mutex_enter(&tcp->tcp_non_sq_lock);
614 flow_stopped = tcp->tcp_flow_stopped;
615 if ((TCP_IS_DETACHED(peer_tcp) &&
616 (peer_tcp->tcp_rcv_cnt >= peer_connp->conn_rcvbuf)) ||
617 (!TCP_IS_DETACHED(peer_tcp) &&
618 !IPCL_IS_NONSTR(peer_connp) && !canputnext(peer_connp->conn_rq))) {
619 peer_data_queued = B_TRUE;
620 }
621
622 if (!flow_stopped && (peer_data_queued ||
623 (TCP_UNSENT_BYTES(tcp) >= connp->conn_sndbuf))) {
624 tcp_setqfull(tcp);
625 flow_stopped = B_TRUE;
626 TCP_STAT(tcps, tcp_fusion_flowctl);
627 DTRACE_PROBE3(tcp__fuse__output__flowctl, tcp_t *, tcp,
628 uint_t, send_size, uint_t, peer_tcp->tcp_rcv_cnt);
629 } else if (flow_stopped && !peer_data_queued &&
630 (TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat)) {
631 tcp_clrqfull(tcp);
632 TCP_STAT(tcps, tcp_fusion_backenabled);
633 flow_stopped = B_FALSE;
634 }
635 mutex_exit(&tcp->tcp_non_sq_lock);
636
637 ipst->ips_loopback_packets++;
638 tcp->tcp_last_sent_len = send_size;
639
640 /* Need to adjust the following SNMP MIB-related variables */
641 tcp->tcp_snxt += send_size;
642 tcp->tcp_suna = tcp->tcp_snxt;
643 peer_tcp->tcp_rnxt += recv_size;
644 peer_tcp->tcp_last_recv_len = recv_size;
645 peer_tcp->tcp_rack = peer_tcp->tcp_rnxt;
646
647 TCPS_BUMP_MIB(tcps, tcpOutDataSegs);
648 TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, send_size);
649
650 TCPS_BUMP_MIB(tcps, tcpHCInSegs);
651 TCPS_BUMP_MIB(tcps, tcpInDataInorderSegs);
652 TCPS_UPDATE_MIB(tcps, tcpInDataInorderBytes, send_size);
653
654 BUMP_LOCAL(tcp->tcp_obsegs);
655 BUMP_LOCAL(peer_tcp->tcp_ibsegs);
656
657 DTRACE_TCP5(send, void, NULL, ip_xmit_attr_t *, connp->conn_ixa,
658 __dtrace_tcp_void_ip_t *, NULL, tcp_t *, tcp,
659 __dtrace_tcp_tcph_t *, NULL);
660 DTRACE_TCP5(receive, void, NULL, ip_xmit_attr_t *,
661 peer_connp->conn_ixa, __dtrace_tcp_void_ip_t *, NULL,
662 tcp_t *, peer_tcp, __dtrace_tcp_tcph_t *, NULL);
663
664 if (!IPCL_IS_NONSTR(peer_tcp->tcp_connp) &&
665 !TCP_IS_DETACHED(peer_tcp)) {
666 /*
667 * Drain the peer's receive queue it has urgent data or if
668 * we're not flow-controlled.
669 */
670 if (urgent || !flow_stopped) {
671 ASSERT(peer_tcp->tcp_rcv_list != NULL);
672 /*
673 * For TLI-based streams, a thread in tcp_accept_swap()
674 * can race with us. That thread will ensure that the
675 * correct peer_connp->conn_rq is globally visible
676 * before peer_tcp->tcp_detached is visible as clear,
677 * but we must also ensure that the load of conn_rq
678 * cannot be reordered to be before the tcp_detached
679 * check.
680 */
681 membar_consumer();
682 (void) tcp_fuse_rcv_drain(peer_connp->conn_rq, peer_tcp,
683 NULL);
684 }
685 }
686 return (B_TRUE);
687 unfuse:
688 tcp_unfuse(tcp);
689 return (B_FALSE);
690 }
691
692 /*
693 * This routine gets called to deliver data upstream on a fused or
694 * previously fused tcp loopback endpoint; the latter happens only
695 * when there is a pending SIGURG signal plus urgent data that can't
696 * be sent upstream in the past.
697 */
698 boolean_t
699 tcp_fuse_rcv_drain(queue_t *q, tcp_t *tcp, mblk_t **sigurg_mpp)
700 {
701 mblk_t *mp;
702 conn_t *connp = tcp->tcp_connp;
703
704 #ifdef DEBUG
705 uint_t cnt = 0;
706 #endif
707 tcp_stack_t *tcps = tcp->tcp_tcps;
708 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
709
710 ASSERT(tcp->tcp_loopback);
711 ASSERT(tcp->tcp_fused || tcp->tcp_fused_sigurg);
712 ASSERT(!tcp->tcp_fused || tcp->tcp_loopback_peer != NULL);
713 ASSERT(IPCL_IS_NONSTR(connp) || sigurg_mpp != NULL || tcp->tcp_fused);
714
715 /* No need for the push timer now, in case it was scheduled */
716 if (tcp->tcp_push_tid != 0) {
717 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
718 tcp->tcp_push_tid = 0;
719 }
720 /*
721 * If there's urgent data sitting in receive list and we didn't
722 * get a chance to send up a SIGURG signal, make sure we send
723 * it first before draining in order to ensure that SIOCATMARK
724 * works properly.
725 */
726 if (tcp->tcp_fused_sigurg) {
727 ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
728
729 tcp->tcp_fused_sigurg = B_FALSE;
730 /*
731 * sigurg_mpp is normally NULL, i.e. when we're still
732 * fused and didn't get here because of tcp_unfuse().
733 * In this case try hard to allocate the M_PCSIG mblk.
734 */
735 if (sigurg_mpp == NULL &&
736 (mp = allocb(1, BPRI_HI)) == NULL &&
737 (mp = allocb_tryhard(1)) == NULL) {
738 /* Alloc failed; try again next time */
739 tcp->tcp_push_tid = TCP_TIMER(tcp,
740 tcp_push_timer, tcps->tcps_push_timer_interval);
741 return (B_TRUE);
742 } else if (sigurg_mpp != NULL) {
743 /*
744 * Use the supplied M_PCSIG mblk; it means we're
745 * either unfused or in the process of unfusing,
746 * and the drain must happen now.
747 */
748 mp = *sigurg_mpp;
749 *sigurg_mpp = NULL;
750 }
751 ASSERT(mp != NULL);
752
753 /* Send up the signal */
754 DB_TYPE(mp) = M_PCSIG;
755 *mp->b_wptr++ = (uchar_t)SIGURG;
756 putnext(q, mp);
757
758 /*
759 * Let the regular tcp_rcv_drain() path handle
760 * draining the data if we're no longer fused.
761 */
762 if (!tcp->tcp_fused)
763 return (B_FALSE);
764 }
765
766 /* Drain the data */
767 while ((mp = tcp->tcp_rcv_list) != NULL) {
768 tcp->tcp_rcv_list = mp->b_next;
769 mp->b_next = NULL;
770 #ifdef DEBUG
771 cnt += msgdsize(mp);
772 #endif
773 ASSERT(!IPCL_IS_NONSTR(connp));
774 putnext(q, mp);
775 TCP_STAT(tcps, tcp_fusion_putnext);
776 }
777
778 #ifdef DEBUG
779 ASSERT(cnt == tcp->tcp_rcv_cnt);
780 #endif
781 tcp->tcp_rcv_last_head = NULL;
782 tcp->tcp_rcv_last_tail = NULL;
783 tcp->tcp_rcv_cnt = 0;
784 tcp->tcp_rwnd = tcp->tcp_connp->conn_rcvbuf;
785
786 mutex_enter(&peer_tcp->tcp_non_sq_lock);
787 if (peer_tcp->tcp_flow_stopped && (TCP_UNSENT_BYTES(peer_tcp) <=
788 peer_tcp->tcp_connp->conn_sndlowat)) {
789 tcp_clrqfull(peer_tcp);
790 TCP_STAT(tcps, tcp_fusion_backenabled);
791 }
792 mutex_exit(&peer_tcp->tcp_non_sq_lock);
793
794 return (B_TRUE);
795 }
796
797 /*
798 * Calculate the size of receive buffer for a fused tcp endpoint.
799 */
800 size_t
801 tcp_fuse_set_rcv_hiwat(tcp_t *tcp, size_t rwnd)
802 {
803 tcp_stack_t *tcps = tcp->tcp_tcps;
804 uint32_t max_win;
805
806 ASSERT(tcp->tcp_fused);
807
808 /* Ensure that value is within the maximum upper bound */
809 if (rwnd > tcps->tcps_max_buf)
810 rwnd = tcps->tcps_max_buf;
811 /*
812 * Round up to system page size in case SO_RCVBUF is modified
813 * after SO_SNDBUF; the latter is also similarly rounded up.
814 */
815 rwnd = P2ROUNDUP_TYPED(rwnd, PAGESIZE, size_t);
816 max_win = TCP_MAXWIN << tcp->tcp_rcv_ws;
817 if (rwnd > max_win) {
818 rwnd = max_win - (max_win % tcp->tcp_mss);
819 if (rwnd < tcp->tcp_mss)
820 rwnd = max_win;
821 }
822
823 /*
824 * Record high water mark, this is used for flow-control
825 * purposes in tcp_fuse_output().
826 */
827 tcp->tcp_connp->conn_rcvbuf = rwnd;
828 tcp->tcp_rwnd = rwnd;
829 return (rwnd);
830 }
831
832 /*
833 * Calculate the maximum outstanding unread data block for a fused tcp endpoint.
834 */
835 int
836 tcp_fuse_maxpsz(tcp_t *tcp)
837 {
838 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
839 conn_t *connp = tcp->tcp_connp;
840 uint_t sndbuf = connp->conn_sndbuf;
841 uint_t maxpsz = sndbuf;
842
843 ASSERT(tcp->tcp_fused);
844 ASSERT(peer_tcp != NULL);
845 ASSERT(peer_tcp->tcp_connp->conn_rcvbuf != 0);
846 /*
847 * In the fused loopback case, we want the stream head to split
848 * up larger writes into smaller chunks for a more accurate flow-
849 * control accounting. Our maxpsz is half of the sender's send
850 * buffer or the receiver's receive buffer, whichever is smaller.
851 * We round up the buffer to system page size due to the lack of
852 * TCP MSS concept in Fusion.
853 */
854 if (maxpsz > peer_tcp->tcp_connp->conn_rcvbuf)
855 maxpsz = peer_tcp->tcp_connp->conn_rcvbuf;
856 maxpsz = P2ROUNDUP_TYPED(maxpsz, PAGESIZE, uint_t) >> 1;
857
858 return (maxpsz);
859 }
860
861 /*
862 * Called to release flow control.
863 */
864 void
865 tcp_fuse_backenable(tcp_t *tcp)
866 {
867 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
868
869 ASSERT(tcp->tcp_fused);
870 ASSERT(peer_tcp != NULL && peer_tcp->tcp_fused);
871 ASSERT(peer_tcp->tcp_loopback_peer == tcp);
872 ASSERT(!TCP_IS_DETACHED(tcp));
873 ASSERT(tcp->tcp_connp->conn_sqp ==
874 peer_tcp->tcp_connp->conn_sqp);
875
876 if (tcp->tcp_rcv_list != NULL)
877 (void) tcp_fuse_rcv_drain(tcp->tcp_connp->conn_rq, tcp, NULL);
878
879 mutex_enter(&peer_tcp->tcp_non_sq_lock);
880 if (peer_tcp->tcp_flow_stopped &&
881 (TCP_UNSENT_BYTES(peer_tcp) <=
882 peer_tcp->tcp_connp->conn_sndlowat)) {
883 tcp_clrqfull(peer_tcp);
884 }
885 mutex_exit(&peer_tcp->tcp_non_sq_lock);
886
887 TCP_STAT(tcp->tcp_tcps, tcp_fusion_backenabled);
888 }