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 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 #include <sys/types.h>
29 #include <sys/stream.h>
30 #include <sys/strsun.h>
31 #include <sys/strsubr.h>
32 #include <sys/debug.h>
33 #include <sys/sdt.h>
34 #include <sys/cmn_err.h>
35 #include <sys/tihdr.h>
36
37 #include <inet/common.h>
38 #include <inet/optcom.h>
39 #include <inet/ip.h>
40 #include <inet/ip_impl.h>
41 #include <inet/tcp.h>
42 #include <inet/tcp_impl.h>
43 #include <inet/ipsec_impl.h>
44 #include <inet/ipclassifier.h>
45 #include <inet/ipp_common.h>
46
47 /*
48 * This file implements TCP fusion - a protocol-less data path for TCP
49 * loopback connections. The fusion of two local TCP endpoints occurs
50 * at connection establishment time. Various conditions (see details
51 * in tcp_fuse()) need to be met for fusion to be successful. If it
52 * fails, we fall back to the regular TCP data path; if it succeeds,
53 * both endpoints proceed to use tcp_fuse_output() as the transmit path.
54 * tcp_fuse_output() enqueues application data directly onto the peer's
55 * receive queue; no protocol processing is involved. After enqueueing
56 * the data, the sender can either push (putnext) data up the receiver's
57 * read queue; or the sender can simply return and let the receiver
58 * retrieve the enqueued data via the synchronous streams entry point
59 * tcp_fuse_rrw(). The latter path is taken if synchronous streams is
60 * enabled (the default). It is disabled if sockfs no longer resides
61 * directly on top of tcp module due to a module insertion or removal.
62 * It also needs to be temporarily disabled when sending urgent data
63 * because the tcp_fuse_rrw() path bypasses the M_PROTO processing done
64 * by strsock_proto() hook.
65 *
66 * Sychronization is handled by squeue and the mutex tcp_non_sq_lock.
67 * One of the requirements for fusion to succeed is that both endpoints
68 * need to be using the same squeue. This ensures that neither side
69 * can disappear while the other side is still sending data. By itself,
70 * squeue is not sufficient for guaranteeing safety when synchronous
71 * streams is enabled. The reason is that tcp_fuse_rrw() doesn't enter
72 * the squeue and its access to tcp_rcv_list and other fusion-related
73 * fields needs to be sychronized with the sender. tcp_non_sq_lock is
74 * used for this purpose. When there is urgent data, the sender needs
75 * to push the data up the receiver's streams read queue. In order to
76 * avoid holding the tcp_non_sq_lock across putnext(), the sender sets
77 * the peer tcp's tcp_fuse_syncstr_plugged bit and releases tcp_non_sq_lock
78 * (see macro TCP_FUSE_SYNCSTR_PLUG_DRAIN()). If tcp_fuse_rrw() enters
79 * after this point, it will see that synchronous streams is plugged and
80 * will wait on tcp_fuse_plugcv. After the sender has finished pushing up
81 * all urgent data, it will clear the tcp_fuse_syncstr_plugged bit using
82 * TCP_FUSE_SYNCSTR_UNPLUG_DRAIN(). This will cause any threads waiting
83 * on tcp_fuse_plugcv to return EBUSY, and in turn cause strget() to call
84 * getq_noenab() to dequeue data from the stream head instead. Once the
85 * data on the stream head has been consumed, tcp_fuse_rrw() may again
86 * be used to process tcp_rcv_list. However, if TCP_FUSE_SYNCSTR_STOP()
87 * has been called, all future calls to tcp_fuse_rrw() will return EBUSY,
88 * effectively disabling synchronous streams.
89 *
90 * The following note applies only to the synchronous streams mode.
91 *
92 * Flow control is done by checking the size of receive buffer and
93 * the number of data blocks, both set to different limits. This is
94 * different than regular streams flow control where cumulative size
95 * check dominates block count check -- streams queue high water mark
96 * typically represents bytes. Each enqueue triggers notifications
97 * to the receiving process; a build up of data blocks indicates a
98 * slow receiver and the sender should be blocked or informed at the
99 * earliest moment instead of further wasting system resources. In
100 * effect, this is equivalent to limiting the number of outstanding
101 * segments in flight.
102 */
103
104 /*
105 * Setting this to false means we disable fusion altogether and
106 * loopback connections would go through the protocol paths.
107 */
108 boolean_t do_tcp_fusion = B_TRUE;
109
110 /*
111 * Enabling this flag allows sockfs to retrieve data directly
112 * from a fused tcp endpoint using synchronous streams interface.
113 */
114 boolean_t do_tcp_direct_sockfs = B_TRUE;
115
116 /*
117 * This is the minimum amount of outstanding writes allowed on
118 * a synchronous streams-enabled receiving endpoint before the
119 * sender gets flow-controlled. Setting this value to 0 means
120 * that the data block limit is equivalent to the byte count
121 * limit, which essentially disables the check.
122 */
123 #define TCP_FUSION_RCV_UNREAD_MIN 8
124 uint_t tcp_fusion_rcv_unread_min = TCP_FUSION_RCV_UNREAD_MIN;
125
126 static void tcp_fuse_syncstr_enable(tcp_t *);
127 static void tcp_fuse_syncstr_disable(tcp_t *);
128 static boolean_t strrput_sig(queue_t *, boolean_t);
129
130 /*
131 * Return true if this connection needs some IP functionality
132 */
133 static boolean_t
134 tcp_loopback_needs_ip(tcp_t *tcp, netstack_t *ns)
135 {
136 ipsec_stack_t *ipss = ns->netstack_ipsec;
137
138 /*
139 * If ire is not cached, do not use fusion
140 */
141 if (tcp->tcp_connp->conn_ire_cache == NULL) {
142 /*
143 * There is no need to hold conn_lock here because when called
144 * from tcp_fuse() there can be no window where conn_ire_cache
145 * can change. This is not true whe called from
146 * tcp_fuse_output(). conn_ire_cache can become null just
147 * after the check, but it's ok if a few packets are delivered
148 * in the fused state.
149 */
150 return (B_TRUE);
151 }
152 if (tcp->tcp_ipversion == IPV4_VERSION) {
153 if (tcp->tcp_ip_hdr_len != IP_SIMPLE_HDR_LENGTH)
154 return (B_TRUE);
155 if (CONN_OUTBOUND_POLICY_PRESENT(tcp->tcp_connp, ipss))
156 return (B_TRUE);
157 if (CONN_INBOUND_POLICY_PRESENT(tcp->tcp_connp, ipss))
158 return (B_TRUE);
159 } else {
160 if (tcp->tcp_ip_hdr_len != IPV6_HDR_LEN)
161 return (B_TRUE);
162 if (CONN_OUTBOUND_POLICY_PRESENT_V6(tcp->tcp_connp, ipss))
163 return (B_TRUE);
164 if (CONN_INBOUND_POLICY_PRESENT_V6(tcp->tcp_connp, ipss))
165 return (B_TRUE);
166 }
167 if (!CONN_IS_LSO_MD_FASTPATH(tcp->tcp_connp))
168 return (B_TRUE);
169 return (B_FALSE);
170 }
171
172
173 /*
174 * This routine gets called by the eager tcp upon changing state from
175 * SYN_RCVD to ESTABLISHED. It fuses a direct path between itself
176 * and the active connect tcp such that the regular tcp processings
177 * may be bypassed under allowable circumstances. Because the fusion
178 * requires both endpoints to be in the same squeue, it does not work
179 * for simultaneous active connects because there is no easy way to
180 * switch from one squeue to another once the connection is created.
181 * This is different from the eager tcp case where we assign it the
182 * same squeue as the one given to the active connect tcp during open.
183 */
184 void
185 tcp_fuse(tcp_t *tcp, uchar_t *iphdr, tcph_t *tcph)
186 {
187 conn_t *peer_connp, *connp = tcp->tcp_connp;
188 tcp_t *peer_tcp;
189 tcp_stack_t *tcps = tcp->tcp_tcps;
190 netstack_t *ns;
191 ip_stack_t *ipst = tcps->tcps_netstack->netstack_ip;
192
193 ASSERT(!tcp->tcp_fused);
194 ASSERT(tcp->tcp_loopback);
195 ASSERT(tcp->tcp_loopback_peer == NULL);
196 /*
197 * We need to inherit q_hiwat of the listener tcp, but we can't
198 * really use tcp_listener since we get here after sending up
199 * T_CONN_IND and tcp_wput_accept() may be called independently,
200 * at which point tcp_listener is cleared; this is why we use
201 * tcp_saved_listener. The listener itself is guaranteed to be
202 * around until tcp_accept_finish() is called on this eager --
203 * this won't happen until we're done since we're inside the
204 * eager's perimeter now.
205 */
206 ASSERT(tcp->tcp_saved_listener != NULL);
207
208 /*
209 * Lookup peer endpoint; search for the remote endpoint having
210 * the reversed address-port quadruplet in ESTABLISHED state,
211 * which is guaranteed to be unique in the system. Zone check
212 * is applied accordingly for loopback address, but not for
213 * local address since we want fusion to happen across Zones.
214 */
215 if (tcp->tcp_ipversion == IPV4_VERSION) {
216 peer_connp = ipcl_conn_tcp_lookup_reversed_ipv4(connp,
217 (ipha_t *)iphdr, tcph, ipst);
218 } else {
219 peer_connp = ipcl_conn_tcp_lookup_reversed_ipv6(connp,
220 (ip6_t *)iphdr, tcph, ipst);
221 }
222
223 /*
224 * We can only proceed if peer exists, resides in the same squeue
225 * as our conn and is not raw-socket. The squeue assignment of
226 * this eager tcp was done earlier at the time of SYN processing
227 * in ip_fanout_tcp{_v6}. Note that similar squeues by itself
228 * doesn't guarantee a safe condition to fuse, hence we perform
229 * additional tests below.
230 */
231 ASSERT(peer_connp == NULL || peer_connp != connp);
232 if (peer_connp == NULL || peer_connp->conn_sqp != connp->conn_sqp ||
233 !IPCL_IS_TCP(peer_connp)) {
234 if (peer_connp != NULL) {
235 TCP_STAT(tcps, tcp_fusion_unqualified);
236 CONN_DEC_REF(peer_connp);
237 }
238 return;
239 }
240 peer_tcp = peer_connp->conn_tcp; /* active connect tcp */
241
242 ASSERT(peer_tcp != NULL && peer_tcp != tcp && !peer_tcp->tcp_fused);
243 ASSERT(peer_tcp->tcp_loopback && peer_tcp->tcp_loopback_peer == NULL);
244 ASSERT(peer_connp->conn_sqp == connp->conn_sqp);
245
246 /*
247 * Fuse the endpoints; we perform further checks against both
248 * tcp endpoints to ensure that a fusion is allowed to happen.
249 * In particular we bail out for non-simple TCP/IP or if IPsec/
250 * IPQoS policy/kernel SSL exists.
251 */
252 ns = tcps->tcps_netstack;
253 ipst = ns->netstack_ip;
254
255 if (!tcp->tcp_unfusable && !peer_tcp->tcp_unfusable &&
256 !tcp_loopback_needs_ip(tcp, ns) &&
257 !tcp_loopback_needs_ip(peer_tcp, ns) &&
258 tcp->tcp_kssl_ent == NULL &&
259 !IPP_ENABLED(IPP_LOCAL_OUT|IPP_LOCAL_IN, ipst)) {
260 mblk_t *mp;
261 struct stroptions *stropt;
262 queue_t *peer_rq = peer_tcp->tcp_rq;
263
264 ASSERT(!TCP_IS_DETACHED(peer_tcp) && peer_rq != NULL);
265 ASSERT(tcp->tcp_fused_sigurg_mp == NULL);
266 ASSERT(peer_tcp->tcp_fused_sigurg_mp == NULL);
267 ASSERT(tcp->tcp_kssl_ctx == NULL);
268
269 /*
270 * We need to drain data on both endpoints during unfuse.
271 * If we need to send up SIGURG at the time of draining,
272 * we want to be sure that an mblk is readily available.
273 * This is why we pre-allocate the M_PCSIG mblks for both
274 * endpoints which will only be used during/after unfuse.
275 */
276 if ((mp = allocb(1, BPRI_HI)) == NULL)
277 goto failed;
278
279 tcp->tcp_fused_sigurg_mp = mp;
280
281 if ((mp = allocb(1, BPRI_HI)) == NULL)
282 goto failed;
283
284 peer_tcp->tcp_fused_sigurg_mp = mp;
285
286 /* Allocate M_SETOPTS mblk */
287 if ((mp = allocb(sizeof (*stropt), BPRI_HI)) == NULL)
288 goto failed;
289
290 /* If either tcp or peer_tcp sodirect enabled then disable */
291 if (tcp->tcp_sodirect != NULL) {
292 mutex_enter(tcp->tcp_sodirect->sod_lock);
293 SOD_DISABLE(tcp->tcp_sodirect);
294 mutex_exit(tcp->tcp_sodirect->sod_lock);
295 tcp->tcp_sodirect = NULL;
296 }
297 if (peer_tcp->tcp_sodirect != NULL) {
298 mutex_enter(peer_tcp->tcp_sodirect->sod_lock);
299 SOD_DISABLE(peer_tcp->tcp_sodirect);
300 mutex_exit(peer_tcp->tcp_sodirect->sod_lock);
301 peer_tcp->tcp_sodirect = NULL;
302 }
303
304 /* Fuse both endpoints */
305 peer_tcp->tcp_loopback_peer = tcp;
306 tcp->tcp_loopback_peer = peer_tcp;
307 peer_tcp->tcp_fused = tcp->tcp_fused = B_TRUE;
308
309 /*
310 * We never use regular tcp paths in fusion and should
311 * therefore clear tcp_unsent on both endpoints. Having
312 * them set to non-zero values means asking for trouble
313 * especially after unfuse, where we may end up sending
314 * through regular tcp paths which expect xmit_list and
315 * friends to be correctly setup.
316 */
317 peer_tcp->tcp_unsent = tcp->tcp_unsent = 0;
318
319 tcp_timers_stop(tcp);
320 tcp_timers_stop(peer_tcp);
321
322 /*
323 * At this point we are a detached eager tcp and therefore
324 * don't have a queue assigned to us until accept happens.
325 * In the mean time the peer endpoint may immediately send
326 * us data as soon as fusion is finished, and we need to be
327 * able to flow control it in case it sends down huge amount
328 * of data while we're still detached. To prevent that we
329 * inherit the listener's q_hiwat value; this is temporary
330 * since we'll repeat the process in tcp_accept_finish().
331 */
332 (void) tcp_fuse_set_rcv_hiwat(tcp,
333 tcp->tcp_saved_listener->tcp_rq->q_hiwat);
334
335 /*
336 * Set the stream head's write offset value to zero since we
337 * won't be needing any room for TCP/IP headers; tell it to
338 * not break up the writes (this would reduce the amount of
339 * work done by kmem); and configure our receive buffer.
340 * Note that we can only do this for the active connect tcp
341 * since our eager is still detached; it will be dealt with
342 * later in tcp_accept_finish().
343 */
344 DB_TYPE(mp) = M_SETOPTS;
345 mp->b_wptr += sizeof (*stropt);
346
347 stropt = (struct stroptions *)mp->b_rptr;
348 stropt->so_flags = SO_MAXBLK | SO_WROFF | SO_HIWAT;
349 stropt->so_maxblk = tcp_maxpsz_set(peer_tcp, B_FALSE);
350 stropt->so_wroff = 0;
351
352 /*
353 * Record the stream head's high water mark for
354 * peer endpoint; this is used for flow-control
355 * purposes in tcp_fuse_output().
356 */
357 stropt->so_hiwat = tcp_fuse_set_rcv_hiwat(peer_tcp,
358 peer_rq->q_hiwat);
359
360 /* Send the options up */
361 putnext(peer_rq, mp);
362 } else {
363 TCP_STAT(tcps, tcp_fusion_unqualified);
364 }
365 CONN_DEC_REF(peer_connp);
366 return;
367
368 failed:
369 if (tcp->tcp_fused_sigurg_mp != NULL) {
370 freeb(tcp->tcp_fused_sigurg_mp);
371 tcp->tcp_fused_sigurg_mp = NULL;
372 }
373 if (peer_tcp->tcp_fused_sigurg_mp != NULL) {
374 freeb(peer_tcp->tcp_fused_sigurg_mp);
375 peer_tcp->tcp_fused_sigurg_mp = NULL;
376 }
377 CONN_DEC_REF(peer_connp);
378 }
379
380 /*
381 * Unfuse a previously-fused pair of tcp loopback endpoints.
382 */
383 void
384 tcp_unfuse(tcp_t *tcp)
385 {
386 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
387
388 ASSERT(tcp->tcp_fused && peer_tcp != NULL);
389 ASSERT(peer_tcp->tcp_fused && peer_tcp->tcp_loopback_peer == tcp);
390 ASSERT(tcp->tcp_connp->conn_sqp == peer_tcp->tcp_connp->conn_sqp);
391 ASSERT(tcp->tcp_unsent == 0 && peer_tcp->tcp_unsent == 0);
392 ASSERT(tcp->tcp_fused_sigurg_mp != NULL);
393 ASSERT(peer_tcp->tcp_fused_sigurg_mp != NULL);
394
395 /*
396 * We disable synchronous streams, drain any queued data and
397 * clear tcp_direct_sockfs. The synchronous streams entry
398 * points will become no-ops after this point.
399 */
400 tcp_fuse_disable_pair(tcp, B_TRUE);
401
402 /*
403 * Update th_seq and th_ack in the header template
404 */
405 U32_TO_ABE32(tcp->tcp_snxt, tcp->tcp_tcph->th_seq);
406 U32_TO_ABE32(tcp->tcp_rnxt, tcp->tcp_tcph->th_ack);
407 U32_TO_ABE32(peer_tcp->tcp_snxt, peer_tcp->tcp_tcph->th_seq);
408 U32_TO_ABE32(peer_tcp->tcp_rnxt, peer_tcp->tcp_tcph->th_ack);
409
410 /* Unfuse the endpoints */
411 peer_tcp->tcp_fused = tcp->tcp_fused = B_FALSE;
412 peer_tcp->tcp_loopback_peer = tcp->tcp_loopback_peer = NULL;
413 }
414
415 /*
416 * Fusion output routine for urgent data. This routine is called by
417 * tcp_fuse_output() for handling non-M_DATA mblks.
418 */
419 void
420 tcp_fuse_output_urg(tcp_t *tcp, mblk_t *mp)
421 {
422 mblk_t *mp1;
423 struct T_exdata_ind *tei;
424 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
425 mblk_t *head, *prev_head = NULL;
426 tcp_stack_t *tcps = tcp->tcp_tcps;
427
428 ASSERT(tcp->tcp_fused);
429 ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
430 ASSERT(DB_TYPE(mp) == M_PROTO || DB_TYPE(mp) == M_PCPROTO);
431 ASSERT(mp->b_cont != NULL && DB_TYPE(mp->b_cont) == M_DATA);
432 ASSERT(MBLKL(mp) >= sizeof (*tei) && MBLKL(mp->b_cont) > 0);
433
434 /*
435 * Urgent data arrives in the form of T_EXDATA_REQ from above.
436 * Each occurence denotes a new urgent pointer. For each new
437 * urgent pointer we signal (SIGURG) the receiving app to indicate
438 * that it needs to go into urgent mode. This is similar to the
439 * urgent data handling in the regular tcp. We don't need to keep
440 * track of where the urgent pointer is, because each T_EXDATA_REQ
441 * "advances" the urgent pointer for us.
442 *
443 * The actual urgent data carried by T_EXDATA_REQ is then prepended
444 * by a T_EXDATA_IND before being enqueued behind any existing data
445 * destined for the receiving app. There is only a single urgent
446 * pointer (out-of-band mark) for a given tcp. If the new urgent
447 * data arrives before the receiving app reads some existing urgent
448 * data, the previous marker is lost. This behavior is emulated
449 * accordingly below, by removing any existing T_EXDATA_IND messages
450 * and essentially converting old urgent data into non-urgent.
451 */
452 ASSERT(tcp->tcp_valid_bits & TCP_URG_VALID);
453 /* Let sender get out of urgent mode */
454 tcp->tcp_valid_bits &= ~TCP_URG_VALID;
455
456 /*
457 * This flag indicates that a signal needs to be sent up.
458 * This flag will only get cleared once SIGURG is delivered and
459 * is not affected by the tcp_fused flag -- delivery will still
460 * happen even after an endpoint is unfused, to handle the case
461 * where the sending endpoint immediately closes/unfuses after
462 * sending urgent data and the accept is not yet finished.
463 */
464 peer_tcp->tcp_fused_sigurg = B_TRUE;
465
466 /* Reuse T_EXDATA_REQ mblk for T_EXDATA_IND */
467 DB_TYPE(mp) = M_PROTO;
468 tei = (struct T_exdata_ind *)mp->b_rptr;
469 tei->PRIM_type = T_EXDATA_IND;
470 tei->MORE_flag = 0;
471 mp->b_wptr = (uchar_t *)&tei[1];
472
473 TCP_STAT(tcps, tcp_fusion_urg);
474 BUMP_MIB(&tcps->tcps_mib, tcpOutUrg);
475
476 head = peer_tcp->tcp_rcv_list;
477 while (head != NULL) {
478 /*
479 * Remove existing T_EXDATA_IND, keep the data which follows
480 * it and relink our list. Note that we don't modify the
481 * tcp_rcv_last_tail since it never points to T_EXDATA_IND.
482 */
483 if (DB_TYPE(head) != M_DATA) {
484 mp1 = head;
485
486 ASSERT(DB_TYPE(mp1->b_cont) == M_DATA);
487 head = mp1->b_cont;
488 mp1->b_cont = NULL;
489 head->b_next = mp1->b_next;
490 mp1->b_next = NULL;
491 if (prev_head != NULL)
492 prev_head->b_next = head;
493 if (peer_tcp->tcp_rcv_list == mp1)
494 peer_tcp->tcp_rcv_list = head;
495 if (peer_tcp->tcp_rcv_last_head == mp1)
496 peer_tcp->tcp_rcv_last_head = head;
497 freeb(mp1);
498 }
499 prev_head = head;
500 head = head->b_next;
501 }
502 }
503
504 /*
505 * Fusion output routine, called by tcp_output() and tcp_wput_proto().
506 * If we are modifying any member that can be changed outside the squeue,
507 * like tcp_flow_stopped, we need to take tcp_non_sq_lock.
508 */
509 boolean_t
510 tcp_fuse_output(tcp_t *tcp, mblk_t *mp, uint32_t send_size)
511 {
512 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
513 uint_t max_unread;
514 boolean_t flow_stopped, peer_data_queued = B_FALSE;
515 boolean_t urgent = (DB_TYPE(mp) != M_DATA);
516 mblk_t *mp1 = mp;
517 ill_t *ilp, *olp;
518 ipha_t *ipha;
519 ip6_t *ip6h;
520 tcph_t *tcph;
521 uint_t ip_hdr_len;
522 uint32_t seq;
523 uint32_t recv_size = send_size;
524 tcp_stack_t *tcps = tcp->tcp_tcps;
525 netstack_t *ns = tcps->tcps_netstack;
526 ip_stack_t *ipst = ns->netstack_ip;
527
528 ASSERT(tcp->tcp_fused);
529 ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
530 ASSERT(tcp->tcp_connp->conn_sqp == peer_tcp->tcp_connp->conn_sqp);
531 ASSERT(DB_TYPE(mp) == M_DATA || DB_TYPE(mp) == M_PROTO ||
532 DB_TYPE(mp) == M_PCPROTO);
533
534
535 /* If this connection requires IP, unfuse and use regular path */
536 if (tcp_loopback_needs_ip(tcp, ns) ||
537 tcp_loopback_needs_ip(peer_tcp, ns) ||
538 IPP_ENABLED(IPP_LOCAL_OUT|IPP_LOCAL_IN, ipst)) {
539 TCP_STAT(tcps, tcp_fusion_aborted);
540 goto unfuse;
541 }
542
543 if (send_size == 0) {
544 freemsg(mp);
545 return (B_TRUE);
546 }
547 max_unread = peer_tcp->tcp_fuse_rcv_unread_hiwater;
548
549 /*
550 * Handle urgent data; we either send up SIGURG to the peer now
551 * or do it later when we drain, in case the peer is detached
552 * or if we're short of memory for M_PCSIG mblk.
553 */
554 if (urgent) {
555 /*
556 * We stop synchronous streams when we have urgent data
557 * queued to prevent tcp_fuse_rrw() from pulling it. If
558 * for some reasons the urgent data can't be delivered
559 * below, synchronous streams will remain stopped until
560 * someone drains the tcp_rcv_list.
561 */
562 TCP_FUSE_SYNCSTR_PLUG_DRAIN(peer_tcp);
563 tcp_fuse_output_urg(tcp, mp);
564
565 mp1 = mp->b_cont;
566 }
567
568 if (tcp->tcp_ipversion == IPV4_VERSION &&
569 (HOOKS4_INTERESTED_LOOPBACK_IN(ipst) ||
570 HOOKS4_INTERESTED_LOOPBACK_OUT(ipst)) ||
571 tcp->tcp_ipversion == IPV6_VERSION &&
572 (HOOKS6_INTERESTED_LOOPBACK_IN(ipst) ||
573 HOOKS6_INTERESTED_LOOPBACK_OUT(ipst))) {
574 /*
575 * Build ip and tcp header to satisfy FW_HOOKS.
576 * We only build it when any hook is present.
577 */
578 if ((mp1 = tcp_xmit_mp(tcp, mp1, tcp->tcp_mss, NULL, NULL,
579 tcp->tcp_snxt, B_TRUE, NULL, B_FALSE)) == NULL)
580 /* If tcp_xmit_mp fails, use regular path */
581 goto unfuse;
582
583 ASSERT(peer_tcp->tcp_connp->conn_ire_cache->ire_ipif != NULL);
584 olp = peer_tcp->tcp_connp->conn_ire_cache->ire_ipif->ipif_ill;
585 /* PFHooks: LOOPBACK_OUT */
586 if (tcp->tcp_ipversion == IPV4_VERSION) {
587 ipha = (ipha_t *)mp1->b_rptr;
588
589 DTRACE_PROBE4(ip4__loopback__out__start,
590 ill_t *, NULL, ill_t *, olp,
591 ipha_t *, ipha, mblk_t *, mp1);
592 FW_HOOKS(ipst->ips_ip4_loopback_out_event,
593 ipst->ips_ipv4firewall_loopback_out,
594 NULL, olp, ipha, mp1, mp1, 0, ipst);
595 DTRACE_PROBE1(ip4__loopback__out__end, mblk_t *, mp1);
596 } else {
597 ip6h = (ip6_t *)mp1->b_rptr;
598
599 DTRACE_PROBE4(ip6__loopback__out__start,
600 ill_t *, NULL, ill_t *, olp,
601 ip6_t *, ip6h, mblk_t *, mp1);
602 FW_HOOKS6(ipst->ips_ip6_loopback_out_event,
603 ipst->ips_ipv6firewall_loopback_out,
604 NULL, olp, ip6h, mp1, mp1, 0, ipst);
605 DTRACE_PROBE1(ip6__loopback__out__end, mblk_t *, mp1);
606 }
607 if (mp1 == NULL)
608 goto unfuse;
609
610
611 /* PFHooks: LOOPBACK_IN */
612 ASSERT(tcp->tcp_connp->conn_ire_cache->ire_ipif != NULL);
613 ilp = tcp->tcp_connp->conn_ire_cache->ire_ipif->ipif_ill;
614
615 if (tcp->tcp_ipversion == IPV4_VERSION) {
616 DTRACE_PROBE4(ip4__loopback__in__start,
617 ill_t *, ilp, ill_t *, NULL,
618 ipha_t *, ipha, mblk_t *, mp1);
619 FW_HOOKS(ipst->ips_ip4_loopback_in_event,
620 ipst->ips_ipv4firewall_loopback_in,
621 ilp, NULL, ipha, mp1, mp1, 0, ipst);
622 DTRACE_PROBE1(ip4__loopback__in__end, mblk_t *, mp1);
623 if (mp1 == NULL)
624 goto unfuse;
625
626 ip_hdr_len = IPH_HDR_LENGTH(ipha);
627 } else {
628 DTRACE_PROBE4(ip6__loopback__in__start,
629 ill_t *, ilp, ill_t *, NULL,
630 ip6_t *, ip6h, mblk_t *, mp1);
631 FW_HOOKS6(ipst->ips_ip6_loopback_in_event,
632 ipst->ips_ipv6firewall_loopback_in,
633 ilp, NULL, ip6h, mp1, mp1, 0, ipst);
634 DTRACE_PROBE1(ip6__loopback__in__end, mblk_t *, mp1);
635 if (mp1 == NULL)
636 goto unfuse;
637
638 ip_hdr_len = ip_hdr_length_v6(mp1, ip6h);
639 }
640
641 /* Data length might be changed by FW_HOOKS */
642 tcph = (tcph_t *)&mp1->b_rptr[ip_hdr_len];
643 seq = ABE32_TO_U32(tcph->th_seq);
644 recv_size += seq - tcp->tcp_snxt;
645
646 /*
647 * The message duplicated by tcp_xmit_mp is freed.
648 * Note: the original message passed in remains unchanged.
649 */
650 freemsg(mp1);
651 }
652
653 mutex_enter(&peer_tcp->tcp_non_sq_lock);
654 /*
655 * Wake up and signal the peer; it is okay to do this before
656 * enqueueing because we are holding the lock. One of the
657 * advantages of synchronous streams is the ability for us to
658 * find out when the application performs a read on the socket,
659 * by way of tcp_fuse_rrw() entry point being called. Every
660 * data that gets enqueued onto the receiver is treated as if
661 * it has arrived at the receiving endpoint, thus generating
662 * SIGPOLL/SIGIO for asynchronous socket just as in the strrput()
663 * case. However, we only wake up the application when necessary,
664 * i.e. during the first enqueue. When tcp_fuse_rrw() is called
665 * it will send everything upstream.
666 */
667 if (peer_tcp->tcp_direct_sockfs && !urgent &&
668 !TCP_IS_DETACHED(peer_tcp)) {
669 /* Update poll events and send SIGPOLL/SIGIO if necessary */
670 STR_WAKEUP_SENDSIG(STREAM(peer_tcp->tcp_rq),
671 peer_tcp->tcp_rcv_list);
672 }
673
674 /*
675 * Enqueue data into the peer's receive list; we may or may not
676 * drain the contents depending on the conditions below.
677 */
678 tcp_rcv_enqueue(peer_tcp, mp, recv_size);
679
680 /* In case it wrapped around and also to keep it constant */
681 peer_tcp->tcp_rwnd += recv_size;
682 /*
683 * We increase the peer's unread message count here whilst still
684 * holding it's tcp_non_sq_lock. This ensures that the increment
685 * occurs in the same lock acquisition perimeter as the enqueue.
686 * Depending on lock hierarchy, we can release these locks which
687 * creates a window in which we can race with tcp_fuse_rrw()
688 */
689 peer_tcp->tcp_fuse_rcv_unread_cnt++;
690
691 /*
692 * Exercise flow-control when needed; we will get back-enabled
693 * in either tcp_accept_finish(), tcp_unfuse(), or tcp_fuse_rrw().
694 * If tcp_direct_sockfs is on or if the peer endpoint is detached,
695 * we emulate streams flow control by checking the peer's queue
696 * size and high water mark; otherwise we simply use canputnext()
697 * to decide if we need to stop our flow.
698 *
699 * The outstanding unread data block check does not apply for a
700 * detached receiver; this is to avoid unnecessary blocking of the
701 * sender while the accept is currently in progress and is quite
702 * similar to the regular tcp.
703 */
704 if (TCP_IS_DETACHED(peer_tcp) || max_unread == 0)
705 max_unread = UINT_MAX;
706
707 /*
708 * Since we are accessing our tcp_flow_stopped and might modify it,
709 * we need to take tcp->tcp_non_sq_lock. The lock for the highest
710 * address is held first. Dropping peer_tcp->tcp_non_sq_lock should
711 * not be an issue here since we are within the squeue and the peer
712 * won't disappear.
713 */
714 if (tcp > peer_tcp) {
715 mutex_exit(&peer_tcp->tcp_non_sq_lock);
716 mutex_enter(&tcp->tcp_non_sq_lock);
717 mutex_enter(&peer_tcp->tcp_non_sq_lock);
718 } else {
719 mutex_enter(&tcp->tcp_non_sq_lock);
720 }
721 flow_stopped = tcp->tcp_flow_stopped;
722 if (((peer_tcp->tcp_direct_sockfs || TCP_IS_DETACHED(peer_tcp)) &&
723 (peer_tcp->tcp_rcv_cnt >= peer_tcp->tcp_fuse_rcv_hiwater ||
724 peer_tcp->tcp_fuse_rcv_unread_cnt >= max_unread)) ||
725 (!peer_tcp->tcp_direct_sockfs && !TCP_IS_DETACHED(peer_tcp) &&
726 !canputnext(peer_tcp->tcp_rq))) {
727 peer_data_queued = B_TRUE;
728 }
729
730 if (!flow_stopped && (peer_data_queued ||
731 (TCP_UNSENT_BYTES(tcp) >= tcp->tcp_xmit_hiwater))) {
732 tcp_setqfull(tcp);
733 flow_stopped = B_TRUE;
734 TCP_STAT(tcps, tcp_fusion_flowctl);
735 DTRACE_PROBE4(tcp__fuse__output__flowctl, tcp_t *, tcp,
736 uint_t, send_size, uint_t, peer_tcp->tcp_rcv_cnt,
737 uint_t, peer_tcp->tcp_fuse_rcv_unread_cnt);
738 } else if (flow_stopped && !peer_data_queued &&
739 (TCP_UNSENT_BYTES(tcp) <= tcp->tcp_xmit_lowater)) {
740 tcp_clrqfull(tcp);
741 TCP_STAT(tcps, tcp_fusion_backenabled);
742 flow_stopped = B_FALSE;
743 }
744 mutex_exit(&tcp->tcp_non_sq_lock);
745
746 /*
747 * If we are in synchronous streams mode and the peer read queue is
748 * not full then schedule a push timer if one is not scheduled
749 * already. This is needed for applications which use MSG_PEEK to
750 * determine the number of bytes available before issuing a 'real'
751 * read. It also makes flow control more deterministic, particularly
752 * for smaller message sizes.
753 */
754 if (!urgent && peer_tcp->tcp_direct_sockfs &&
755 peer_tcp->tcp_push_tid == 0 && !TCP_IS_DETACHED(peer_tcp) &&
756 canputnext(peer_tcp->tcp_rq)) {
757 peer_tcp->tcp_push_tid = TCP_TIMER(peer_tcp, tcp_push_timer,
758 MSEC_TO_TICK(tcps->tcps_push_timer_interval));
759 }
760 mutex_exit(&peer_tcp->tcp_non_sq_lock);
761 ipst->ips_loopback_packets++;
762 tcp->tcp_last_sent_len = send_size;
763
764 /* Need to adjust the following SNMP MIB-related variables */
765 tcp->tcp_snxt += send_size;
766 tcp->tcp_suna = tcp->tcp_snxt;
767 peer_tcp->tcp_rnxt += recv_size;
768 peer_tcp->tcp_rack = peer_tcp->tcp_rnxt;
769
770 BUMP_MIB(&tcps->tcps_mib, tcpOutDataSegs);
771 UPDATE_MIB(&tcps->tcps_mib, tcpOutDataBytes, send_size);
772
773 BUMP_MIB(&tcps->tcps_mib, tcpInSegs);
774 BUMP_MIB(&tcps->tcps_mib, tcpInDataInorderSegs);
775 UPDATE_MIB(&tcps->tcps_mib, tcpInDataInorderBytes, send_size);
776
777 BUMP_LOCAL(tcp->tcp_obsegs);
778 BUMP_LOCAL(peer_tcp->tcp_ibsegs);
779
780 DTRACE_PROBE2(tcp__fuse__output, tcp_t *, tcp, uint_t, send_size);
781
782 if (!TCP_IS_DETACHED(peer_tcp)) {
783 /*
784 * Drain the peer's receive queue it has urgent data or if
785 * we're not flow-controlled. There is no need for draining
786 * normal data when tcp_direct_sockfs is on because the peer
787 * will pull the data via tcp_fuse_rrw().
788 */
789 if (urgent || (!flow_stopped && !peer_tcp->tcp_direct_sockfs)) {
790 ASSERT(peer_tcp->tcp_rcv_list != NULL);
791 /*
792 * For TLI-based streams, a thread in tcp_accept_swap()
793 * can race with us. That thread will ensure that the
794 * correct peer_tcp->tcp_rq is globally visible before
795 * peer_tcp->tcp_detached is visible as clear, but we
796 * must also ensure that the load of tcp_rq cannot be
797 * reordered to be before the tcp_detached check.
798 */
799 membar_consumer();
800 (void) tcp_fuse_rcv_drain(peer_tcp->tcp_rq, peer_tcp,
801 NULL);
802 /*
803 * If synchronous streams was stopped above due
804 * to the presence of urgent data, re-enable it.
805 */
806 if (urgent)
807 TCP_FUSE_SYNCSTR_UNPLUG_DRAIN(peer_tcp);
808 }
809 }
810 return (B_TRUE);
811 unfuse:
812 tcp_unfuse(tcp);
813 return (B_FALSE);
814 }
815
816 /*
817 * This routine gets called to deliver data upstream on a fused or
818 * previously fused tcp loopback endpoint; the latter happens only
819 * when there is a pending SIGURG signal plus urgent data that can't
820 * be sent upstream in the past.
821 */
822 boolean_t
823 tcp_fuse_rcv_drain(queue_t *q, tcp_t *tcp, mblk_t **sigurg_mpp)
824 {
825 mblk_t *mp;
826 #ifdef DEBUG
827 uint_t cnt = 0;
828 #endif
829 tcp_stack_t *tcps = tcp->tcp_tcps;
830 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
831 boolean_t sd_rd_eof = B_FALSE;
832
833 ASSERT(tcp->tcp_loopback);
834 ASSERT(tcp->tcp_fused || tcp->tcp_fused_sigurg);
835 ASSERT(!tcp->tcp_fused || tcp->tcp_loopback_peer != NULL);
836 ASSERT(sigurg_mpp != NULL || tcp->tcp_fused);
837
838 /* No need for the push timer now, in case it was scheduled */
839 if (tcp->tcp_push_tid != 0) {
840 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
841 tcp->tcp_push_tid = 0;
842 }
843 /*
844 * If there's urgent data sitting in receive list and we didn't
845 * get a chance to send up a SIGURG signal, make sure we send
846 * it first before draining in order to ensure that SIOCATMARK
847 * works properly.
848 */
849 if (tcp->tcp_fused_sigurg) {
850 /*
851 * sigurg_mpp is normally NULL, i.e. when we're still
852 * fused and didn't get here because of tcp_unfuse().
853 * In this case try hard to allocate the M_PCSIG mblk.
854 */
855 if (sigurg_mpp == NULL &&
856 (mp = allocb(1, BPRI_HI)) == NULL &&
857 (mp = allocb_tryhard(1)) == NULL) {
858 /* Alloc failed; try again next time */
859 tcp->tcp_push_tid = TCP_TIMER(tcp, tcp_push_timer,
860 MSEC_TO_TICK(tcps->tcps_push_timer_interval));
861 return (B_TRUE);
862 } else if (sigurg_mpp != NULL) {
863 /*
864 * Use the supplied M_PCSIG mblk; it means we're
865 * either unfused or in the process of unfusing,
866 * and the drain must happen now.
867 */
868 mp = *sigurg_mpp;
869 *sigurg_mpp = NULL;
870 }
871 ASSERT(mp != NULL);
872
873 tcp->tcp_fused_sigurg = B_FALSE;
874 /* Send up the signal */
875 DB_TYPE(mp) = M_PCSIG;
876 *mp->b_wptr++ = (uchar_t)SIGURG;
877 putnext(q, mp);
878 /*
879 * Let the regular tcp_rcv_drain() path handle
880 * draining the data if we're no longer fused.
881 */
882 if (!tcp->tcp_fused)
883 return (B_FALSE);
884 }
885
886 /*
887 * In the synchronous streams case, we generate SIGPOLL/SIGIO for
888 * each M_DATA that gets enqueued onto the receiver. At this point
889 * we are about to drain any queued data via putnext(). In order
890 * to avoid extraneous signal generation from strrput(), we set
891 * STRGETINPROG flag at the stream head prior to the draining and
892 * restore it afterwards. This masks out signal generation only
893 * for M_DATA messages and does not affect urgent data. We only do
894 * this if the STREOF flag is not set which can happen if the
895 * application shuts down the read side of a stream. In this case
896 * we simply free these messages to approximate the flushq behavior
897 * which normally occurs when STREOF is on the stream head read queue.
898 */
899 if (tcp->tcp_direct_sockfs)
900 sd_rd_eof = strrput_sig(q, B_FALSE);
901
902 /* Drain the data */
903 while ((mp = tcp->tcp_rcv_list) != NULL) {
904 tcp->tcp_rcv_list = mp->b_next;
905 mp->b_next = NULL;
906 #ifdef DEBUG
907 cnt += msgdsize(mp);
908 #endif
909 if (sd_rd_eof) {
910 freemsg(mp);
911 } else {
912 putnext(q, mp);
913 TCP_STAT(tcps, tcp_fusion_putnext);
914 }
915 }
916
917 if (tcp->tcp_direct_sockfs && !sd_rd_eof)
918 (void) strrput_sig(q, B_TRUE);
919
920 ASSERT(cnt == tcp->tcp_rcv_cnt);
921 tcp->tcp_rcv_last_head = NULL;
922 tcp->tcp_rcv_last_tail = NULL;
923 tcp->tcp_rcv_cnt = 0;
924 tcp->tcp_fuse_rcv_unread_cnt = 0;
925 tcp->tcp_rwnd = q->q_hiwat;
926
927 if (peer_tcp->tcp_flow_stopped && (TCP_UNSENT_BYTES(peer_tcp) <=
928 peer_tcp->tcp_xmit_lowater)) {
929 tcp_clrqfull(peer_tcp);
930 TCP_STAT(tcps, tcp_fusion_backenabled);
931 }
932
933 return (B_TRUE);
934 }
935
936 /*
937 * Synchronous stream entry point for sockfs to retrieve
938 * data directly from tcp_rcv_list.
939 * tcp_fuse_rrw() might end up modifying the peer's tcp_flow_stopped,
940 * for which it must take the tcp_non_sq_lock of the peer as well
941 * making any change. The order of taking the locks is based on
942 * the TCP pointer itself. Before we get the peer we need to take
943 * our tcp_non_sq_lock so that the peer doesn't disappear. However,
944 * we cannot drop the lock if we have to grab the peer's lock (because
945 * of ordering), since the peer might disappear in the interim. So,
946 * we take our tcp_non_sq_lock, get the peer, increment the ref on the
947 * peer's conn, drop all the locks and then take the tcp_non_sq_lock in the
948 * desired order. Incrementing the conn ref on the peer means that the
949 * peer won't disappear when we drop our tcp_non_sq_lock.
950 */
951 int
952 tcp_fuse_rrw(queue_t *q, struiod_t *dp)
953 {
954 tcp_t *tcp = Q_TO_CONN(q)->conn_tcp;
955 mblk_t *mp;
956 tcp_t *peer_tcp;
957 tcp_stack_t *tcps = tcp->tcp_tcps;
958
959 mutex_enter(&tcp->tcp_non_sq_lock);
960
961 /*
962 * If tcp_fuse_syncstr_plugged is set, then another thread is moving
963 * the underlying data to the stream head. We need to wait until it's
964 * done, then return EBUSY so that strget() will dequeue data from the
965 * stream head to ensure data is drained in-order.
966 */
967 plugged:
968 if (tcp->tcp_fuse_syncstr_plugged) {
969 do {
970 cv_wait(&tcp->tcp_fuse_plugcv, &tcp->tcp_non_sq_lock);
971 } while (tcp->tcp_fuse_syncstr_plugged);
972
973 mutex_exit(&tcp->tcp_non_sq_lock);
974 TCP_STAT(tcps, tcp_fusion_rrw_plugged);
975 TCP_STAT(tcps, tcp_fusion_rrw_busy);
976 return (EBUSY);
977 }
978
979 peer_tcp = tcp->tcp_loopback_peer;
980
981 /*
982 * If someone had turned off tcp_direct_sockfs or if synchronous
983 * streams is stopped, we return EBUSY. This causes strget() to
984 * dequeue data from the stream head instead.
985 */
986 if (!tcp->tcp_direct_sockfs || tcp->tcp_fuse_syncstr_stopped) {
987 mutex_exit(&tcp->tcp_non_sq_lock);
988 TCP_STAT(tcps, tcp_fusion_rrw_busy);
989 return (EBUSY);
990 }
991
992 /*
993 * Grab lock in order. The highest addressed tcp is locked first.
994 * We don't do this within the tcp_rcv_list check since if we
995 * have to drop the lock, for ordering, then the tcp_rcv_list
996 * could change.
997 */
998 if (peer_tcp > tcp) {
999 CONN_INC_REF(peer_tcp->tcp_connp);
1000 mutex_exit(&tcp->tcp_non_sq_lock);
1001 mutex_enter(&peer_tcp->tcp_non_sq_lock);
1002 mutex_enter(&tcp->tcp_non_sq_lock);
1003 /*
1004 * This might have changed in the interim
1005 * Once read-side tcp_non_sq_lock is dropped above
1006 * anything can happen, we need to check all
1007 * known conditions again once we reaquire
1008 * read-side tcp_non_sq_lock.
1009 */
1010 if (tcp->tcp_fuse_syncstr_plugged) {
1011 mutex_exit(&peer_tcp->tcp_non_sq_lock);
1012 CONN_DEC_REF(peer_tcp->tcp_connp);
1013 goto plugged;
1014 }
1015 if (!tcp->tcp_direct_sockfs || tcp->tcp_fuse_syncstr_stopped) {
1016 mutex_exit(&tcp->tcp_non_sq_lock);
1017 mutex_exit(&peer_tcp->tcp_non_sq_lock);
1018 CONN_DEC_REF(peer_tcp->tcp_connp);
1019 TCP_STAT(tcps, tcp_fusion_rrw_busy);
1020 return (EBUSY);
1021 }
1022 CONN_DEC_REF(peer_tcp->tcp_connp);
1023 } else {
1024 mutex_enter(&peer_tcp->tcp_non_sq_lock);
1025 }
1026
1027 if ((mp = tcp->tcp_rcv_list) != NULL) {
1028
1029 DTRACE_PROBE3(tcp__fuse__rrw, tcp_t *, tcp,
1030 uint32_t, tcp->tcp_rcv_cnt, ssize_t, dp->d_uio.uio_resid);
1031
1032 tcp->tcp_rcv_list = NULL;
1033 TCP_STAT(tcps, tcp_fusion_rrw_msgcnt);
1034
1035 /*
1036 * At this point nothing should be left in tcp_rcv_list.
1037 * The only possible case where we would have a chain of
1038 * b_next-linked messages is urgent data, but we wouldn't
1039 * be here if that's true since urgent data is delivered
1040 * via putnext() and synchronous streams is stopped until
1041 * tcp_fuse_rcv_drain() is finished.
1042 */
1043 ASSERT(DB_TYPE(mp) == M_DATA && mp->b_next == NULL);
1044
1045 tcp->tcp_rcv_last_head = NULL;
1046 tcp->tcp_rcv_last_tail = NULL;
1047 tcp->tcp_rcv_cnt = 0;
1048 tcp->tcp_fuse_rcv_unread_cnt = 0;
1049
1050 if (peer_tcp->tcp_flow_stopped &&
1051 (TCP_UNSENT_BYTES(peer_tcp) <=
1052 peer_tcp->tcp_xmit_lowater)) {
1053 tcp_clrqfull(peer_tcp);
1054 TCP_STAT(tcps, tcp_fusion_backenabled);
1055 }
1056 }
1057 mutex_exit(&peer_tcp->tcp_non_sq_lock);
1058 /*
1059 * Either we just dequeued everything or we get here from sockfs
1060 * and have nothing to return; in this case clear RSLEEP.
1061 */
1062 ASSERT(tcp->tcp_rcv_last_head == NULL);
1063 ASSERT(tcp->tcp_rcv_last_tail == NULL);
1064 ASSERT(tcp->tcp_rcv_cnt == 0);
1065 ASSERT(tcp->tcp_fuse_rcv_unread_cnt == 0);
1066 STR_WAKEUP_CLEAR(STREAM(q));
1067
1068 mutex_exit(&tcp->tcp_non_sq_lock);
1069 dp->d_mp = mp;
1070 return (0);
1071 }
1072
1073 /*
1074 * Synchronous stream entry point used by certain ioctls to retrieve
1075 * information about or peek into the tcp_rcv_list.
1076 */
1077 int
1078 tcp_fuse_rinfop(queue_t *q, infod_t *dp)
1079 {
1080 tcp_t *tcp = Q_TO_CONN(q)->conn_tcp;
1081 mblk_t *mp;
1082 uint_t cmd = dp->d_cmd;
1083 int res = 0;
1084 int error = 0;
1085 struct stdata *stp = STREAM(q);
1086
1087 mutex_enter(&tcp->tcp_non_sq_lock);
1088 /* If shutdown on read has happened, return nothing */
1089 mutex_enter(&stp->sd_lock);
1090 if (stp->sd_flag & STREOF) {
1091 mutex_exit(&stp->sd_lock);
1092 goto done;
1093 }
1094 mutex_exit(&stp->sd_lock);
1095
1096 /*
1097 * It is OK not to return an answer if tcp_rcv_list is
1098 * currently not accessible.
1099 */
1100 if (!tcp->tcp_direct_sockfs || tcp->tcp_fuse_syncstr_stopped ||
1101 tcp->tcp_fuse_syncstr_plugged || (mp = tcp->tcp_rcv_list) == NULL)
1102 goto done;
1103
1104 if (cmd & INFOD_COUNT) {
1105 /*
1106 * We have at least one message and
1107 * could return only one at a time.
1108 */
1109 dp->d_count++;
1110 res |= INFOD_COUNT;
1111 }
1112 if (cmd & INFOD_BYTES) {
1113 /*
1114 * Return size of all data messages.
1115 */
1116 dp->d_bytes += tcp->tcp_rcv_cnt;
1117 res |= INFOD_BYTES;
1118 }
1119 if (cmd & INFOD_FIRSTBYTES) {
1120 /*
1121 * Return size of first data message.
1122 */
1123 dp->d_bytes = msgdsize(mp);
1124 res |= INFOD_FIRSTBYTES;
1125 dp->d_cmd &= ~INFOD_FIRSTBYTES;
1126 }
1127 if (cmd & INFOD_COPYOUT) {
1128 mblk_t *mp1;
1129 int n;
1130
1131 if (DB_TYPE(mp) == M_DATA) {
1132 mp1 = mp;
1133 } else {
1134 mp1 = mp->b_cont;
1135 ASSERT(mp1 != NULL);
1136 }
1137
1138 /*
1139 * Return data contents of first message.
1140 */
1141 ASSERT(DB_TYPE(mp1) == M_DATA);
1142 while (mp1 != NULL && dp->d_uiop->uio_resid > 0) {
1143 n = MIN(dp->d_uiop->uio_resid, MBLKL(mp1));
1144 if (n != 0 && (error = uiomove((char *)mp1->b_rptr, n,
1145 UIO_READ, dp->d_uiop)) != 0) {
1146 goto done;
1147 }
1148 mp1 = mp1->b_cont;
1149 }
1150 res |= INFOD_COPYOUT;
1151 dp->d_cmd &= ~INFOD_COPYOUT;
1152 }
1153 done:
1154 mutex_exit(&tcp->tcp_non_sq_lock);
1155
1156 dp->d_res |= res;
1157
1158 return (error);
1159 }
1160
1161 /*
1162 * Enable synchronous streams on a fused tcp loopback endpoint.
1163 */
1164 static void
1165 tcp_fuse_syncstr_enable(tcp_t *tcp)
1166 {
1167 queue_t *rq = tcp->tcp_rq;
1168 struct stdata *stp = STREAM(rq);
1169
1170 /* We can only enable synchronous streams for sockfs mode */
1171 tcp->tcp_direct_sockfs = tcp->tcp_issocket && do_tcp_direct_sockfs;
1172
1173 if (!tcp->tcp_direct_sockfs)
1174 return;
1175
1176 mutex_enter(&stp->sd_lock);
1177 mutex_enter(QLOCK(rq));
1178
1179 /*
1180 * We replace our q_qinfo with one that has the qi_rwp entry point.
1181 * Clear SR_SIGALLDATA because we generate the equivalent signal(s)
1182 * for every enqueued data in tcp_fuse_output().
1183 */
1184 rq->q_qinfo = &tcp_loopback_rinit;
1185 rq->q_struiot = tcp_loopback_rinit.qi_struiot;
1186 stp->sd_struiordq = rq;
1187 stp->sd_rput_opt &= ~SR_SIGALLDATA;
1188
1189 mutex_exit(QLOCK(rq));
1190 mutex_exit(&stp->sd_lock);
1191 }
1192
1193 /*
1194 * Disable synchronous streams on a fused tcp loopback endpoint.
1195 */
1196 static void
1197 tcp_fuse_syncstr_disable(tcp_t *tcp)
1198 {
1199 queue_t *rq = tcp->tcp_rq;
1200 struct stdata *stp = STREAM(rq);
1201
1202 if (!tcp->tcp_direct_sockfs)
1203 return;
1204
1205 mutex_enter(&stp->sd_lock);
1206 mutex_enter(QLOCK(rq));
1207
1208 /*
1209 * Reset q_qinfo to point to the default tcp entry points.
1210 * Also restore SR_SIGALLDATA so that strrput() can generate
1211 * the signals again for future M_DATA messages.
1212 */
1213 rq->q_qinfo = &tcp_rinitv4; /* No open - same as rinitv6 */
1214 rq->q_struiot = tcp_rinitv4.qi_struiot;
1215 stp->sd_struiordq = NULL;
1216 stp->sd_rput_opt |= SR_SIGALLDATA;
1217 tcp->tcp_direct_sockfs = B_FALSE;
1218
1219 mutex_exit(QLOCK(rq));
1220 mutex_exit(&stp->sd_lock);
1221 }
1222
1223 /*
1224 * Enable synchronous streams on a pair of fused tcp endpoints.
1225 */
1226 void
1227 tcp_fuse_syncstr_enable_pair(tcp_t *tcp)
1228 {
1229 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
1230
1231 ASSERT(tcp->tcp_fused);
1232 ASSERT(peer_tcp != NULL);
1233
1234 tcp_fuse_syncstr_enable(tcp);
1235 tcp_fuse_syncstr_enable(peer_tcp);
1236 }
1237
1238 /*
1239 * Used to enable/disable signal generation at the stream head. We already
1240 * generated the signal(s) for these messages when they were enqueued on the
1241 * receiver. We also check if STREOF is set here. If it is, we return false
1242 * and let the caller decide what to do.
1243 */
1244 static boolean_t
1245 strrput_sig(queue_t *q, boolean_t on)
1246 {
1247 struct stdata *stp = STREAM(q);
1248
1249 mutex_enter(&stp->sd_lock);
1250 if (stp->sd_flag == STREOF) {
1251 mutex_exit(&stp->sd_lock);
1252 return (B_TRUE);
1253 }
1254 if (on)
1255 stp->sd_flag &= ~STRGETINPROG;
1256 else
1257 stp->sd_flag |= STRGETINPROG;
1258 mutex_exit(&stp->sd_lock);
1259
1260 return (B_FALSE);
1261 }
1262
1263 /*
1264 * Disable synchronous streams on a pair of fused tcp endpoints and drain
1265 * any queued data; called either during unfuse or upon transitioning from
1266 * a socket to a stream endpoint due to _SIOCSOCKFALLBACK.
1267 */
1268 void
1269 tcp_fuse_disable_pair(tcp_t *tcp, boolean_t unfusing)
1270 {
1271 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
1272 tcp_stack_t *tcps = tcp->tcp_tcps;
1273
1274 ASSERT(tcp->tcp_fused);
1275 ASSERT(peer_tcp != NULL);
1276
1277 /*
1278 * Force any tcp_fuse_rrw() calls to block until we've moved the data
1279 * onto the stream head.
1280 */
1281 TCP_FUSE_SYNCSTR_PLUG_DRAIN(tcp);
1282 TCP_FUSE_SYNCSTR_PLUG_DRAIN(peer_tcp);
1283
1284 /*
1285 * Cancel any pending push timers.
1286 */
1287 if (tcp->tcp_push_tid != 0) {
1288 (void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
1289 tcp->tcp_push_tid = 0;
1290 }
1291 if (peer_tcp->tcp_push_tid != 0) {
1292 (void) TCP_TIMER_CANCEL(peer_tcp, peer_tcp->tcp_push_tid);
1293 peer_tcp->tcp_push_tid = 0;
1294 }
1295
1296 /*
1297 * Drain any pending data; the detached check is needed because
1298 * we may be called as a result of a tcp_unfuse() triggered by
1299 * tcp_fuse_output(). Note that in case of a detached tcp, the
1300 * draining will happen later after the tcp is unfused. For non-
1301 * urgent data, this can be handled by the regular tcp_rcv_drain().
1302 * If we have urgent data sitting in the receive list, we will
1303 * need to send up a SIGURG signal first before draining the data.
1304 * All of these will be handled by the code in tcp_fuse_rcv_drain()
1305 * when called from tcp_rcv_drain().
1306 */
1307 if (!TCP_IS_DETACHED(tcp)) {
1308 (void) tcp_fuse_rcv_drain(tcp->tcp_rq, tcp,
1309 (unfusing ? &tcp->tcp_fused_sigurg_mp : NULL));
1310 }
1311 if (!TCP_IS_DETACHED(peer_tcp)) {
1312 (void) tcp_fuse_rcv_drain(peer_tcp->tcp_rq, peer_tcp,
1313 (unfusing ? &peer_tcp->tcp_fused_sigurg_mp : NULL));
1314 }
1315
1316 /*
1317 * Make all current and future tcp_fuse_rrw() calls fail with EBUSY.
1318 * To ensure threads don't sneak past the checks in tcp_fuse_rrw(),
1319 * a given stream must be stopped prior to being unplugged (but the
1320 * ordering of operations between the streams is unimportant).
1321 */
1322 TCP_FUSE_SYNCSTR_STOP(tcp);
1323 TCP_FUSE_SYNCSTR_STOP(peer_tcp);
1324 TCP_FUSE_SYNCSTR_UNPLUG_DRAIN(tcp);
1325 TCP_FUSE_SYNCSTR_UNPLUG_DRAIN(peer_tcp);
1326
1327 /* Lift up any flow-control conditions */
1328 if (tcp->tcp_flow_stopped) {
1329 tcp_clrqfull(tcp);
1330 TCP_STAT(tcps, tcp_fusion_backenabled);
1331 }
1332 if (peer_tcp->tcp_flow_stopped) {
1333 tcp_clrqfull(peer_tcp);
1334 TCP_STAT(tcps, tcp_fusion_backenabled);
1335 }
1336
1337 /* Disable synchronous streams */
1338 tcp_fuse_syncstr_disable(tcp);
1339 tcp_fuse_syncstr_disable(peer_tcp);
1340 }
1341
1342 /*
1343 * Calculate the size of receive buffer for a fused tcp endpoint.
1344 */
1345 size_t
1346 tcp_fuse_set_rcv_hiwat(tcp_t *tcp, size_t rwnd)
1347 {
1348 tcp_stack_t *tcps = tcp->tcp_tcps;
1349
1350 ASSERT(tcp->tcp_fused);
1351
1352 /* Ensure that value is within the maximum upper bound */
1353 if (rwnd > tcps->tcps_max_buf)
1354 rwnd = tcps->tcps_max_buf;
1355
1356 /* Obey the absolute minimum tcp receive high water mark */
1357 if (rwnd < tcps->tcps_sth_rcv_hiwat)
1358 rwnd = tcps->tcps_sth_rcv_hiwat;
1359
1360 /*
1361 * Round up to system page size in case SO_RCVBUF is modified
1362 * after SO_SNDBUF; the latter is also similarly rounded up.
1363 */
1364 rwnd = P2ROUNDUP_TYPED(rwnd, PAGESIZE, size_t);
1365 tcp->tcp_fuse_rcv_hiwater = rwnd;
1366 return (rwnd);
1367 }
1368
1369 /*
1370 * Calculate the maximum outstanding unread data block for a fused tcp endpoint.
1371 */
1372 int
1373 tcp_fuse_maxpsz_set(tcp_t *tcp)
1374 {
1375 tcp_t *peer_tcp = tcp->tcp_loopback_peer;
1376 uint_t sndbuf = tcp->tcp_xmit_hiwater;
1377 uint_t maxpsz = sndbuf;
1378
1379 ASSERT(tcp->tcp_fused);
1380 ASSERT(peer_tcp != NULL);
1381 ASSERT(peer_tcp->tcp_fuse_rcv_hiwater != 0);
1382 /*
1383 * In the fused loopback case, we want the stream head to split
1384 * up larger writes into smaller chunks for a more accurate flow-
1385 * control accounting. Our maxpsz is half of the sender's send
1386 * buffer or the receiver's receive buffer, whichever is smaller.
1387 * We round up the buffer to system page size due to the lack of
1388 * TCP MSS concept in Fusion.
1389 */
1390 if (maxpsz > peer_tcp->tcp_fuse_rcv_hiwater)
1391 maxpsz = peer_tcp->tcp_fuse_rcv_hiwater;
1392 maxpsz = P2ROUNDUP_TYPED(maxpsz, PAGESIZE, uint_t) >> 1;
1393
1394 /*
1395 * Calculate the peer's limit for the number of outstanding unread
1396 * data block. This is the amount of data blocks that are allowed
1397 * to reside in the receiver's queue before the sender gets flow
1398 * controlled. It is used only in the synchronous streams mode as
1399 * a way to throttle the sender when it performs consecutive writes
1400 * faster than can be read. The value is derived from SO_SNDBUF in
1401 * order to give the sender some control; we divide it with a large
1402 * value (16KB) to produce a fairly low initial limit.
1403 */
1404 if (tcp_fusion_rcv_unread_min == 0) {
1405 /* A value of 0 means that we disable the check */
1406 peer_tcp->tcp_fuse_rcv_unread_hiwater = 0;
1407 } else {
1408 peer_tcp->tcp_fuse_rcv_unread_hiwater =
1409 MAX(sndbuf >> 14, tcp_fusion_rcv_unread_min);
1410 }
1411 return (maxpsz);
1412 }