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 * Copyright (c) 2015 by Delphix. All rights reserved.
24 */
25
26#include <sys/types.h>
27#include <sys/stream.h>
28#include <sys/strsun.h>
29#include <sys/strsubr.h>
30#include <sys/debug.h>
31#include <sys/sdt.h>
32#include <sys/cmn_err.h>
33#include <sys/tihdr.h>
34
35#include <inet/common.h>
36#include <inet/optcom.h>
37#include <inet/ip.h>
38#include <inet/ip_if.h>
39#include <inet/ip_impl.h>
40#include <inet/tcp.h>
41#include <inet/tcp_impl.h>
42#include <inet/ipsec_impl.h>
43#include <inet/ipclassifier.h>
44#include <inet/ipp_common.h>
45#include <inet/ip_if.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.
56 *
57 * Sychronization is handled by squeue and the mutex tcp_non_sq_lock.
58 * One of the requirements for fusion to succeed is that both endpoints
59 * need to be using the same squeue.  This ensures that neither side
60 * can disappear while the other side is still sending data. Flow
61 * control information is manipulated outside the squeue, so the
62 * tcp_non_sq_lock must be held when touching tcp_flow_stopped.
63 */
64
65/*
66 * Setting this to false means we disable fusion altogether and
67 * loopback connections would go through the protocol paths.
68 */
69boolean_t do_tcp_fusion = B_TRUE;
70
71/*
72 * This routine gets called by the eager tcp upon changing state from
73 * SYN_RCVD to ESTABLISHED.  It fuses a direct path between itself
74 * and the active connect tcp such that the regular tcp processings
75 * may be bypassed under allowable circumstances.  Because the fusion
76 * requires both endpoints to be in the same squeue, it does not work
77 * for simultaneous active connects because there is no easy way to
78 * switch from one squeue to another once the connection is created.
79 * This is different from the eager tcp case where we assign it the
80 * same squeue as the one given to the active connect tcp during open.
81 */
82void
83tcp_fuse(tcp_t *tcp, uchar_t *iphdr, tcpha_t *tcpha)
84{
85	conn_t		*peer_connp, *connp = tcp->tcp_connp;
86	tcp_t		*peer_tcp;
87	tcp_stack_t	*tcps = tcp->tcp_tcps;
88	netstack_t	*ns;
89	ip_stack_t	*ipst = tcps->tcps_netstack->netstack_ip;
90
91	ASSERT(!tcp->tcp_fused);
92	ASSERT(tcp->tcp_loopback);
93	ASSERT(tcp->tcp_loopback_peer == NULL);
94	/*
95	 * We need to inherit conn_rcvbuf of the listener tcp,
96	 * but we can't really use tcp_listener since we get here after
97	 * sending up T_CONN_IND and tcp_tli_accept() may be called
98	 * independently, at which point tcp_listener is cleared;
99	 * this is why we use tcp_saved_listener. The listener itself
100	 * is guaranteed to be around until tcp_accept_finish() is called
101	 * on this eager -- this won't happen until we're done since we're
102	 * inside the eager's perimeter now.
103	 */
104	ASSERT(tcp->tcp_saved_listener != NULL);
105	/*
106	 * Lookup peer endpoint; search for the remote endpoint having
107	 * the reversed address-port quadruplet in ESTABLISHED state,
108	 * which is guaranteed to be unique in the system.  Zone check
109	 * is applied accordingly for loopback address, but not for
110	 * local address since we want fusion to happen across Zones.
111	 */
112	if (connp->conn_ipversion == IPV4_VERSION) {
113		peer_connp = ipcl_conn_tcp_lookup_reversed_ipv4(connp,
114		    (ipha_t *)iphdr, tcpha, ipst);
115	} else {
116		peer_connp = ipcl_conn_tcp_lookup_reversed_ipv6(connp,
117		    (ip6_t *)iphdr, tcpha, ipst);
118	}
119
120	/*
121	 * We can only proceed if peer exists, resides in the same squeue
122	 * as our conn and is not raw-socket. We also restrict fusion to
123	 * endpoints of the same type (STREAMS or non-STREAMS). The squeue
124	 * assignment of this eager tcp was done earlier at the time of SYN
125	 * processing in ip_fanout_tcp{_v6}.  Note that similar squeues by
126	 * itself doesn't guarantee a safe condition to fuse, hence we perform
127	 * additional tests below.
128	 */
129	ASSERT(peer_connp == NULL || peer_connp != connp);
130	if (peer_connp == NULL || peer_connp->conn_sqp != connp->conn_sqp ||
131	    !IPCL_IS_TCP(peer_connp) ||
132	    IPCL_IS_NONSTR(connp) != IPCL_IS_NONSTR(peer_connp)) {
133		if (peer_connp != NULL) {
134			TCP_STAT(tcps, tcp_fusion_unqualified);
135			CONN_DEC_REF(peer_connp);
136		}
137		return;
138	}
139	peer_tcp = peer_connp->conn_tcp;	/* active connect tcp */
140
141	ASSERT(peer_tcp != NULL && peer_tcp != tcp && !peer_tcp->tcp_fused);
142	ASSERT(peer_tcp->tcp_loopback_peer == NULL);
143	ASSERT(peer_connp->conn_sqp == connp->conn_sqp);
144
145	/*
146	 * Due to IRE changes the peer and us might not agree on tcp_loopback.
147	 * We bail in that case.
148	 */
149	if (!peer_tcp->tcp_loopback) {
150		TCP_STAT(tcps, tcp_fusion_unqualified);
151		CONN_DEC_REF(peer_connp);
152		return;
153	}
154	/*
155	 * Fuse the endpoints; we perform further checks against both
156	 * tcp endpoints to ensure that a fusion is allowed to happen.
157	 */
158	ns = tcps->tcps_netstack;
159	ipst = ns->netstack_ip;
160
161	if (!tcp->tcp_unfusable && !peer_tcp->tcp_unfusable &&
162	    tcp->tcp_xmit_head == NULL && peer_tcp->tcp_xmit_head == NULL) {
163		mblk_t *mp = NULL;
164		queue_t *peer_rq = peer_connp->conn_rq;
165
166		ASSERT(!TCP_IS_DETACHED(peer_tcp));
167		ASSERT(tcp->tcp_fused_sigurg_mp == NULL);
168		ASSERT(peer_tcp->tcp_fused_sigurg_mp == NULL);
169
170		/*
171		 * We need to drain data on both endpoints during unfuse.
172		 * If we need to send up SIGURG at the time of draining,
173		 * we want to be sure that an mblk is readily available.
174		 * This is why we pre-allocate the M_PCSIG mblks for both
175		 * endpoints which will only be used during/after unfuse.
176		 * The mblk might already exist if we are doing a re-fuse.
177		 */
178		if (!IPCL_IS_NONSTR(tcp->tcp_connp)) {
179			ASSERT(!IPCL_IS_NONSTR(peer_tcp->tcp_connp));
180
181			if (tcp->tcp_fused_sigurg_mp == NULL) {
182				if ((mp = allocb(1, BPRI_HI)) == NULL)
183					goto failed;
184				tcp->tcp_fused_sigurg_mp = mp;
185			}
186
187			if (peer_tcp->tcp_fused_sigurg_mp == NULL) {
188				if ((mp = allocb(1, BPRI_HI)) == NULL)
189					goto failed;
190				peer_tcp->tcp_fused_sigurg_mp = mp;
191			}
192
193			if ((mp = allocb(sizeof (struct stroptions),
194			    BPRI_HI)) == NULL)
195				goto failed;
196		}
197
198		/* Fuse both endpoints */
199		peer_tcp->tcp_loopback_peer = tcp;
200		tcp->tcp_loopback_peer = peer_tcp;
201		peer_tcp->tcp_fused = tcp->tcp_fused = B_TRUE;
202
203		/*
204		 * We never use regular tcp paths in fusion and should
205		 * therefore clear tcp_unsent on both endpoints.  Having
206		 * them set to non-zero values means asking for trouble
207		 * especially after unfuse, where we may end up sending
208		 * through regular tcp paths which expect xmit_list and
209		 * friends to be correctly setup.
210		 */
211		peer_tcp->tcp_unsent = tcp->tcp_unsent = 0;
212
213		tcp_timers_stop(tcp);
214		tcp_timers_stop(peer_tcp);
215
216		/*
217		 * Set receive buffer and max packet size for the
218		 * active open tcp.
219		 * eager's values will be set in tcp_accept_finish.
220		 */
221		(void) tcp_rwnd_set(peer_tcp, peer_tcp->tcp_connp->conn_rcvbuf);
222
223		/*
224		 * Set the write offset value to zero since we won't
225		 * be needing any room for TCP/IP headers.
226		 */
227		if (!IPCL_IS_NONSTR(peer_tcp->tcp_connp)) {
228			struct stroptions *stropt;
229
230			DB_TYPE(mp) = M_SETOPTS;
231			mp->b_wptr += sizeof (*stropt);
232
233			stropt = (struct stroptions *)mp->b_rptr;
234			stropt->so_flags = SO_WROFF | SO_MAXBLK;
235			stropt->so_wroff = 0;
236			stropt->so_maxblk = INFPSZ;
237
238			/* Send the options up */
239			putnext(peer_rq, mp);
240		} else {
241			struct sock_proto_props sopp;
242
243			/* The peer is a non-STREAMS end point */
244			ASSERT(IPCL_IS_TCP(peer_connp));
245
246			sopp.sopp_flags = SOCKOPT_WROFF | SOCKOPT_MAXBLK;
247			sopp.sopp_wroff = 0;
248			sopp.sopp_maxblk = INFPSZ;
249			(*peer_connp->conn_upcalls->su_set_proto_props)
250			    (peer_connp->conn_upper_handle, &sopp);
251		}
252	} else {
253		TCP_STAT(tcps, tcp_fusion_unqualified);
254	}
255	CONN_DEC_REF(peer_connp);
256	return;
257
258failed:
259	if (tcp->tcp_fused_sigurg_mp != NULL) {
260		freeb(tcp->tcp_fused_sigurg_mp);
261		tcp->tcp_fused_sigurg_mp = NULL;
262	}
263	if (peer_tcp->tcp_fused_sigurg_mp != NULL) {
264		freeb(peer_tcp->tcp_fused_sigurg_mp);
265		peer_tcp->tcp_fused_sigurg_mp = NULL;
266	}
267	CONN_DEC_REF(peer_connp);
268}
269
270/*
271 * Unfuse a previously-fused pair of tcp loopback endpoints.
272 */
273void
274tcp_unfuse(tcp_t *tcp)
275{
276	tcp_t *peer_tcp = tcp->tcp_loopback_peer;
277	tcp_stack_t *tcps = tcp->tcp_tcps;
278
279	ASSERT(tcp->tcp_fused && peer_tcp != NULL);
280	ASSERT(peer_tcp->tcp_fused && peer_tcp->tcp_loopback_peer == tcp);
281	ASSERT(tcp->tcp_connp->conn_sqp == peer_tcp->tcp_connp->conn_sqp);
282	ASSERT(tcp->tcp_unsent == 0 && peer_tcp->tcp_unsent == 0);
283
284	/*
285	 * Cancel any pending push timers.
286	 */
287	if (tcp->tcp_push_tid != 0) {
288		(void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
289		tcp->tcp_push_tid = 0;
290	}
291	if (peer_tcp->tcp_push_tid != 0) {
292		(void) TCP_TIMER_CANCEL(peer_tcp, peer_tcp->tcp_push_tid);
293		peer_tcp->tcp_push_tid = 0;
294	}
295
296	/*
297	 * Drain any pending data; Note that in case of a detached tcp, the
298	 * draining will happen later after the tcp is unfused.  For non-
299	 * urgent data, this can be handled by the regular tcp_rcv_drain().
300	 * If we have urgent data sitting in the receive list, we will
301	 * need to send up a SIGURG signal first before draining the data.
302	 * All of these will be handled by the code in tcp_fuse_rcv_drain()
303	 * when called from tcp_rcv_drain().
304	 */
305	if (!TCP_IS_DETACHED(tcp)) {
306		(void) tcp_fuse_rcv_drain(tcp->tcp_connp->conn_rq, tcp,
307		    &tcp->tcp_fused_sigurg_mp);
308	}
309	if (!TCP_IS_DETACHED(peer_tcp)) {
310		(void) tcp_fuse_rcv_drain(peer_tcp->tcp_connp->conn_rq,
311		    peer_tcp,  &peer_tcp->tcp_fused_sigurg_mp);
312	}
313
314	/* Lift up any flow-control conditions */
315	mutex_enter(&tcp->tcp_non_sq_lock);
316	if (tcp->tcp_flow_stopped) {
317		tcp_clrqfull(tcp);
318		TCP_STAT(tcps, tcp_fusion_backenabled);
319	}
320	mutex_exit(&tcp->tcp_non_sq_lock);
321
322	mutex_enter(&peer_tcp->tcp_non_sq_lock);
323	if (peer_tcp->tcp_flow_stopped) {
324		tcp_clrqfull(peer_tcp);
325		TCP_STAT(tcps, tcp_fusion_backenabled);
326	}
327	mutex_exit(&peer_tcp->tcp_non_sq_lock);
328
329	/*
330	 * Update tha_seq and tha_ack in the header template
331	 */
332	tcp->tcp_tcpha->tha_seq = htonl(tcp->tcp_snxt);
333	tcp->tcp_tcpha->tha_ack = htonl(tcp->tcp_rnxt);
334	peer_tcp->tcp_tcpha->tha_seq = htonl(peer_tcp->tcp_snxt);
335	peer_tcp->tcp_tcpha->tha_ack = htonl(peer_tcp->tcp_rnxt);
336
337	/* Unfuse the endpoints */
338	peer_tcp->tcp_fused = tcp->tcp_fused = B_FALSE;
339	peer_tcp->tcp_loopback_peer = tcp->tcp_loopback_peer = NULL;
340}
341
342/*
343 * Fusion output routine used to handle urgent data sent by STREAMS based
344 * endpoints. This routine is called by tcp_fuse_output() for handling
345 * non-M_DATA mblks.
346 */
347void
348tcp_fuse_output_urg(tcp_t *tcp, mblk_t *mp)
349{
350	mblk_t *mp1;
351	struct T_exdata_ind *tei;
352	tcp_t *peer_tcp = tcp->tcp_loopback_peer;
353	mblk_t *head, *prev_head = NULL;
354	tcp_stack_t	*tcps = tcp->tcp_tcps;
355
356	ASSERT(tcp->tcp_fused);
357	ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
358	ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
359	ASSERT(DB_TYPE(mp) == M_PROTO || DB_TYPE(mp) == M_PCPROTO);
360	ASSERT(mp->b_cont != NULL && DB_TYPE(mp->b_cont) == M_DATA);
361	ASSERT(MBLKL(mp) >= sizeof (*tei) && MBLKL(mp->b_cont) > 0);
362
363	/*
364	 * Urgent data arrives in the form of T_EXDATA_REQ from above.
365	 * Each occurence denotes a new urgent pointer.  For each new
366	 * urgent pointer we signal (SIGURG) the receiving app to indicate
367	 * that it needs to go into urgent mode.  This is similar to the
368	 * urgent data handling in the regular tcp.  We don't need to keep
369	 * track of where the urgent pointer is, because each T_EXDATA_REQ
370	 * "advances" the urgent pointer for us.
371	 *
372	 * The actual urgent data carried by T_EXDATA_REQ is then prepended
373	 * by a T_EXDATA_IND before being enqueued behind any existing data
374	 * destined for the receiving app.  There is only a single urgent
375	 * pointer (out-of-band mark) for a given tcp.  If the new urgent
376	 * data arrives before the receiving app reads some existing urgent
377	 * data, the previous marker is lost.  This behavior is emulated
378	 * accordingly below, by removing any existing T_EXDATA_IND messages
379	 * and essentially converting old urgent data into non-urgent.
380	 */
381	ASSERT(tcp->tcp_valid_bits & TCP_URG_VALID);
382	/* Let sender get out of urgent mode */
383	tcp->tcp_valid_bits &= ~TCP_URG_VALID;
384
385	/*
386	 * This flag indicates that a signal needs to be sent up.
387	 * This flag will only get cleared once SIGURG is delivered and
388	 * is not affected by the tcp_fused flag -- delivery will still
389	 * happen even after an endpoint is unfused, to handle the case
390	 * where the sending endpoint immediately closes/unfuses after
391	 * sending urgent data and the accept is not yet finished.
392	 */
393	peer_tcp->tcp_fused_sigurg = B_TRUE;
394
395	/* Reuse T_EXDATA_REQ mblk for T_EXDATA_IND */
396	DB_TYPE(mp) = M_PROTO;
397	tei = (struct T_exdata_ind *)mp->b_rptr;
398	tei->PRIM_type = T_EXDATA_IND;
399	tei->MORE_flag = 0;
400	mp->b_wptr = (uchar_t *)&tei[1];
401
402	TCP_STAT(tcps, tcp_fusion_urg);
403	TCPS_BUMP_MIB(tcps, tcpOutUrg);
404
405	head = peer_tcp->tcp_rcv_list;
406	while (head != NULL) {
407		/*
408		 * Remove existing T_EXDATA_IND, keep the data which follows
409		 * it and relink our list.  Note that we don't modify the
410		 * tcp_rcv_last_tail since it never points to T_EXDATA_IND.
411		 */
412		if (DB_TYPE(head) != M_DATA) {
413			mp1 = head;
414
415			ASSERT(DB_TYPE(mp1->b_cont) == M_DATA);
416			head = mp1->b_cont;
417			mp1->b_cont = NULL;
418			head->b_next = mp1->b_next;
419			mp1->b_next = NULL;
420			if (prev_head != NULL)
421				prev_head->b_next = head;
422			if (peer_tcp->tcp_rcv_list == mp1)
423				peer_tcp->tcp_rcv_list = head;
424			if (peer_tcp->tcp_rcv_last_head == mp1)
425				peer_tcp->tcp_rcv_last_head = head;
426			freeb(mp1);
427		}
428		prev_head = head;
429		head = head->b_next;
430	}
431}
432
433/*
434 * Fusion output routine, called by tcp_output() and tcp_wput_proto().
435 * If we are modifying any member that can be changed outside the squeue,
436 * like tcp_flow_stopped, we need to take tcp_non_sq_lock.
437 */
438boolean_t
439tcp_fuse_output(tcp_t *tcp, mblk_t *mp, uint32_t send_size)
440{
441	conn_t		*connp = tcp->tcp_connp;
442	tcp_t		*peer_tcp = tcp->tcp_loopback_peer;
443	conn_t		*peer_connp = peer_tcp->tcp_connp;
444	boolean_t	flow_stopped, peer_data_queued = B_FALSE;
445	boolean_t	urgent = (DB_TYPE(mp) != M_DATA);
446	boolean_t	push = B_TRUE;
447	mblk_t		*mp1 = mp;
448	uint_t		ip_hdr_len;
449	uint32_t	recv_size = send_size;
450	tcp_stack_t	*tcps = tcp->tcp_tcps;
451	netstack_t	*ns = tcps->tcps_netstack;
452	ip_stack_t	*ipst = ns->netstack_ip;
453	ipsec_stack_t	*ipss = ns->netstack_ipsec;
454	iaflags_t	ixaflags = connp->conn_ixa->ixa_flags;
455	boolean_t	do_ipsec, hooks_out, hooks_in, ipobs_enabled;
456
457	ASSERT(tcp->tcp_fused);
458	ASSERT(peer_tcp != NULL && peer_tcp->tcp_loopback_peer == tcp);
459	ASSERT(connp->conn_sqp == peer_connp->conn_sqp);
460	ASSERT(DB_TYPE(mp) == M_DATA || DB_TYPE(mp) == M_PROTO ||
461	    DB_TYPE(mp) == M_PCPROTO);
462
463	if (send_size == 0) {
464		freemsg(mp);
465		return (B_TRUE);
466	}
467
468	/*
469	 * Handle urgent data; we either send up SIGURG to the peer now
470	 * or do it later when we drain, in case the peer is detached
471	 * or if we're short of memory for M_PCSIG mblk.
472	 */
473	if (urgent) {
474		tcp_fuse_output_urg(tcp, mp);
475
476		mp1 = mp->b_cont;
477	}
478
479	/*
480	 * Check that we are still using an IRE_LOCAL or IRE_LOOPBACK before
481	 * further processes.
482	 */
483	if (!ip_output_verify_local(connp->conn_ixa))
484		goto unfuse;
485
486	/*
487	 * Build IP and TCP header in case we have something that needs the
488	 * headers. Those cases are:
489	 * 1. IPsec
490	 * 2. IPobs
491	 * 3. FW_HOOKS
492	 *
493	 * If tcp_xmit_mp() fails to dupb() the message, unfuse the connection
494	 * and back to regular path.
495	 */
496	if (ixaflags & IXAF_IS_IPV4) {
497		do_ipsec = (ixaflags & IXAF_IPSEC_SECURE) ||
498		    CONN_INBOUND_POLICY_PRESENT(peer_connp, ipss);
499
500		hooks_out = HOOKS4_INTERESTED_LOOPBACK_OUT(ipst);
501		hooks_in = HOOKS4_INTERESTED_LOOPBACK_IN(ipst);
502		ipobs_enabled = (ipst->ips_ip4_observe.he_interested != 0);
503	} else {
504		do_ipsec = (ixaflags & IXAF_IPSEC_SECURE) ||
505		    CONN_INBOUND_POLICY_PRESENT_V6(peer_connp, ipss);
506
507		hooks_out = HOOKS6_INTERESTED_LOOPBACK_OUT(ipst);
508		hooks_in = HOOKS6_INTERESTED_LOOPBACK_IN(ipst);
509		ipobs_enabled = (ipst->ips_ip6_observe.he_interested != 0);
510	}
511
512	/* We do logical 'or' for efficiency */
513	if (ipobs_enabled | do_ipsec | hooks_in | hooks_out) {
514		if ((mp1 = tcp_xmit_mp(tcp, mp1, tcp->tcp_mss, NULL, NULL,
515		    tcp->tcp_snxt, B_TRUE, NULL, B_FALSE)) == NULL)
516			/* If tcp_xmit_mp fails, use regular path */
517			goto unfuse;
518
519		/*
520		 * Leave all IP relevant processes to ip_output_process_local(),
521		 * which handles IPsec, IPobs, and FW_HOOKS.
522		 */
523		mp1 = ip_output_process_local(mp1, connp->conn_ixa, hooks_out,
524		    hooks_in, do_ipsec ? peer_connp : NULL);
525
526		/* If the message is dropped for any reason. */
527		if (mp1 == NULL)
528			goto unfuse;
529
530		/*
531		 * Data length might have been changed by FW_HOOKS.
532		 * We assume that the first mblk contains the TCP/IP headers.
533		 */
534		if (hooks_in || hooks_out) {
535			tcpha_t *tcpha;
536
537			ip_hdr_len = (ixaflags & IXAF_IS_IPV4) ?
538			    IPH_HDR_LENGTH((ipha_t *)mp1->b_rptr) :
539			    ip_hdr_length_v6(mp1, (ip6_t *)mp1->b_rptr);
540
541			tcpha = (tcpha_t *)&mp1->b_rptr[ip_hdr_len];
542			ASSERT((uchar_t *)tcpha + sizeof (tcpha_t) <=
543			    mp1->b_wptr);
544			recv_size += htonl(tcpha->tha_seq) - tcp->tcp_snxt;
545
546		}
547
548		/*
549		 * The message duplicated by tcp_xmit_mp is freed.
550		 * Note: the original message passed in remains unchanged.
551		 */
552		freemsg(mp1);
553	}
554
555	/*
556	 * Enqueue data into the peer's receive list; we may or may not
557	 * drain the contents depending on the conditions below.
558	 *
559	 * For non-STREAMS sockets we normally queue data directly in the
560	 * socket by calling the su_recv upcall. However, if the peer is
561	 * detached we use tcp_rcv_enqueue() instead. Queued data will be
562	 * drained when the accept completes (in tcp_accept_finish()).
563	 */
564	if (IPCL_IS_NONSTR(peer_connp) &&
565	    !TCP_IS_DETACHED(peer_tcp)) {
566		int error;
567		int flags = 0;
568
569		if ((tcp->tcp_valid_bits & TCP_URG_VALID) &&
570		    (tcp->tcp_urg == tcp->tcp_snxt)) {
571			flags = MSG_OOB;
572			(*peer_connp->conn_upcalls->su_signal_oob)
573			    (peer_connp->conn_upper_handle, 0);
574			tcp->tcp_valid_bits &= ~TCP_URG_VALID;
575		}
576		if ((*peer_connp->conn_upcalls->su_recv)(
577		    peer_connp->conn_upper_handle, mp, recv_size,
578		    flags, &error, &push) < 0) {
579			ASSERT(error != EOPNOTSUPP);
580			peer_data_queued = B_TRUE;
581		}
582	} else {
583		if (IPCL_IS_NONSTR(peer_connp) &&
584		    (tcp->tcp_valid_bits & TCP_URG_VALID) &&
585		    (tcp->tcp_urg == tcp->tcp_snxt)) {
586			/*
587			 * Can not deal with urgent pointers
588			 * that arrive before the connection has been
589			 * accept()ed.
590			 */
591			tcp->tcp_valid_bits &= ~TCP_URG_VALID;
592			freemsg(mp);
593			return (B_TRUE);
594		}
595
596		tcp_rcv_enqueue(peer_tcp, mp, recv_size,
597		    tcp->tcp_connp->conn_cred);
598
599		/* In case it wrapped around and also to keep it constant */
600		peer_tcp->tcp_rwnd += recv_size;
601	}
602
603	/*
604	 * Exercise flow-control when needed; we will get back-enabled
605	 * in either tcp_accept_finish(), tcp_unfuse(), or when data is
606	 * consumed. If peer endpoint is detached, we emulate streams flow
607	 * control by checking the peer's queue size and high water mark;
608	 * otherwise we simply use canputnext() to decide if we need to stop
609	 * our flow.
610	 *
611	 * Since we are accessing our tcp_flow_stopped and might modify it,
612	 * we need to take tcp->tcp_non_sq_lock.
613	 */
614	mutex_enter(&tcp->tcp_non_sq_lock);
615	flow_stopped = tcp->tcp_flow_stopped;
616	if ((TCP_IS_DETACHED(peer_tcp) &&
617	    (peer_tcp->tcp_rcv_cnt >= peer_connp->conn_rcvbuf)) ||
618	    (!TCP_IS_DETACHED(peer_tcp) &&
619	    !IPCL_IS_NONSTR(peer_connp) && !canputnext(peer_connp->conn_rq))) {
620		peer_data_queued = B_TRUE;
621	}
622
623	if (!flow_stopped && (peer_data_queued ||
624	    (TCP_UNSENT_BYTES(tcp) >= connp->conn_sndbuf))) {
625		tcp_setqfull(tcp);
626		flow_stopped = B_TRUE;
627		TCP_STAT(tcps, tcp_fusion_flowctl);
628		DTRACE_PROBE3(tcp__fuse__output__flowctl, tcp_t *, tcp,
629		    uint_t, send_size, uint_t, peer_tcp->tcp_rcv_cnt);
630	} else if (flow_stopped && !peer_data_queued &&
631	    (TCP_UNSENT_BYTES(tcp) <= connp->conn_sndlowat)) {
632		tcp_clrqfull(tcp);
633		TCP_STAT(tcps, tcp_fusion_backenabled);
634		flow_stopped = B_FALSE;
635	}
636	mutex_exit(&tcp->tcp_non_sq_lock);
637
638	ipst->ips_loopback_packets++;
639	tcp->tcp_last_sent_len = send_size;
640
641	/* Need to adjust the following SNMP MIB-related variables */
642	tcp->tcp_snxt += send_size;
643	tcp->tcp_suna = tcp->tcp_snxt;
644	peer_tcp->tcp_rnxt += recv_size;
645	peer_tcp->tcp_last_recv_len = recv_size;
646	peer_tcp->tcp_rack = peer_tcp->tcp_rnxt;
647
648	TCPS_BUMP_MIB(tcps, tcpOutDataSegs);
649	TCPS_BUMP_MIB(tcps, tcpHCOutSegs);
650	TCPS_UPDATE_MIB(tcps, tcpOutDataBytes, send_size);
651	tcp->tcp_cs.tcp_out_data_bytes += send_size;
652	tcp->tcp_cs.tcp_out_data_segs++;
653
654	TCPS_BUMP_MIB(tcps, tcpHCInSegs);
655	TCPS_BUMP_MIB(tcps, tcpInDataInorderSegs);
656	TCPS_UPDATE_MIB(tcps, tcpInDataInorderBytes, send_size);
657	peer_tcp->tcp_cs.tcp_in_data_inorder_bytes += send_size;
658	peer_tcp->tcp_cs.tcp_in_data_inorder_segs++;
659
660	DTRACE_TCP5(send, void, NULL, ip_xmit_attr_t *, connp->conn_ixa,
661	    __dtrace_tcp_void_ip_t *, NULL, tcp_t *, tcp,
662	    __dtrace_tcp_tcph_t *, NULL);
663	DTRACE_TCP5(receive, void, NULL, ip_xmit_attr_t *,
664	    peer_connp->conn_ixa, __dtrace_tcp_void_ip_t *, NULL,
665	    tcp_t *, peer_tcp, __dtrace_tcp_tcph_t *, NULL);
666
667	if (!IPCL_IS_NONSTR(peer_tcp->tcp_connp) &&
668	    !TCP_IS_DETACHED(peer_tcp)) {
669		/*
670		 * Drain the peer's receive queue it has urgent data or if
671		 * we're not flow-controlled.
672		 */
673		if (urgent || !flow_stopped) {
674			ASSERT(peer_tcp->tcp_rcv_list != NULL);
675			/*
676			 * For TLI-based streams, a thread in tcp_accept_swap()
677			 * can race with us.  That thread will ensure that the
678			 * correct peer_connp->conn_rq is globally visible
679			 * before peer_tcp->tcp_detached is visible as clear,
680			 * but we must also ensure that the load of conn_rq
681			 * cannot be reordered to be before the tcp_detached
682			 * check.
683			 */
684			membar_consumer();
685			(void) tcp_fuse_rcv_drain(peer_connp->conn_rq, peer_tcp,
686			    NULL);
687		}
688	}
689	return (B_TRUE);
690unfuse:
691	tcp_unfuse(tcp);
692	return (B_FALSE);
693}
694
695/*
696 * This routine gets called to deliver data upstream on a fused or
697 * previously fused tcp loopback endpoint; the latter happens only
698 * when there is a pending SIGURG signal plus urgent data that can't
699 * be sent upstream in the past.
700 */
701boolean_t
702tcp_fuse_rcv_drain(queue_t *q, tcp_t *tcp, mblk_t **sigurg_mpp)
703{
704	mblk_t *mp;
705	conn_t	*connp = tcp->tcp_connp;
706
707#ifdef DEBUG
708	uint_t cnt = 0;
709#endif
710	tcp_stack_t	*tcps = tcp->tcp_tcps;
711	tcp_t		*peer_tcp = tcp->tcp_loopback_peer;
712
713	ASSERT(tcp->tcp_loopback);
714	ASSERT(tcp->tcp_fused || tcp->tcp_fused_sigurg);
715	ASSERT(!tcp->tcp_fused || tcp->tcp_loopback_peer != NULL);
716	ASSERT(IPCL_IS_NONSTR(connp) || sigurg_mpp != NULL || tcp->tcp_fused);
717
718	/* No need for the push timer now, in case it was scheduled */
719	if (tcp->tcp_push_tid != 0) {
720		(void) TCP_TIMER_CANCEL(tcp, tcp->tcp_push_tid);
721		tcp->tcp_push_tid = 0;
722	}
723	/*
724	 * If there's urgent data sitting in receive list and we didn't
725	 * get a chance to send up a SIGURG signal, make sure we send
726	 * it first before draining in order to ensure that SIOCATMARK
727	 * works properly.
728	 */
729	if (tcp->tcp_fused_sigurg) {
730		ASSERT(!IPCL_IS_NONSTR(tcp->tcp_connp));
731
732		tcp->tcp_fused_sigurg = B_FALSE;
733		/*
734		 * sigurg_mpp is normally NULL, i.e. when we're still
735		 * fused and didn't get here because of tcp_unfuse().
736		 * In this case try hard to allocate the M_PCSIG mblk.
737		 */
738		if (sigurg_mpp == NULL &&
739		    (mp = allocb(1, BPRI_HI)) == NULL &&
740		    (mp = allocb_tryhard(1)) == NULL) {
741			/* Alloc failed; try again next time */
742			tcp->tcp_push_tid = TCP_TIMER(tcp,
743			    tcp_push_timer, tcps->tcps_push_timer_interval);
744			return (B_TRUE);
745		} else if (sigurg_mpp != NULL) {
746			/*
747			 * Use the supplied M_PCSIG mblk; it means we're
748			 * either unfused or in the process of unfusing,
749			 * and the drain must happen now.
750			 */
751			mp = *sigurg_mpp;
752			*sigurg_mpp = NULL;
753		}
754		ASSERT(mp != NULL);
755
756		/* Send up the signal */
757		DB_TYPE(mp) = M_PCSIG;
758		*mp->b_wptr++ = (uchar_t)SIGURG;
759		putnext(q, mp);
760
761		/*
762		 * Let the regular tcp_rcv_drain() path handle
763		 * draining the data if we're no longer fused.
764		 */
765		if (!tcp->tcp_fused)
766			return (B_FALSE);
767	}
768
769	/* Drain the data */
770	while ((mp = tcp->tcp_rcv_list) != NULL) {
771		tcp->tcp_rcv_list = mp->b_next;
772		mp->b_next = NULL;
773#ifdef DEBUG
774		cnt += msgdsize(mp);
775#endif
776		ASSERT(!IPCL_IS_NONSTR(connp));
777		putnext(q, mp);
778		TCP_STAT(tcps, tcp_fusion_putnext);
779	}
780
781#ifdef DEBUG
782	ASSERT(cnt == tcp->tcp_rcv_cnt);
783#endif
784	tcp->tcp_rcv_last_head = NULL;
785	tcp->tcp_rcv_last_tail = NULL;
786	tcp->tcp_rcv_cnt = 0;
787	tcp->tcp_rwnd = tcp->tcp_connp->conn_rcvbuf;
788
789	mutex_enter(&peer_tcp->tcp_non_sq_lock);
790	if (peer_tcp->tcp_flow_stopped && (TCP_UNSENT_BYTES(peer_tcp) <=
791	    peer_tcp->tcp_connp->conn_sndlowat)) {
792		tcp_clrqfull(peer_tcp);
793		TCP_STAT(tcps, tcp_fusion_backenabled);
794	}
795	mutex_exit(&peer_tcp->tcp_non_sq_lock);
796
797	return (B_TRUE);
798}
799
800/*
801 * Calculate the size of receive buffer for a fused tcp endpoint.
802 */
803size_t
804tcp_fuse_set_rcv_hiwat(tcp_t *tcp, size_t rwnd)
805{
806	tcp_stack_t	*tcps = tcp->tcp_tcps;
807	uint32_t	max_win;
808
809	ASSERT(tcp->tcp_fused);
810
811	/* Ensure that value is within the maximum upper bound */
812	if (rwnd > tcps->tcps_max_buf)
813		rwnd = tcps->tcps_max_buf;
814	/*
815	 * Round up to system page size in case SO_RCVBUF is modified
816	 * after SO_SNDBUF; the latter is also similarly rounded up.
817	 */
818	rwnd = P2ROUNDUP_TYPED(rwnd, PAGESIZE, size_t);
819	max_win = TCP_MAXWIN << tcp->tcp_rcv_ws;
820	if (rwnd > max_win) {
821		rwnd = max_win - (max_win % tcp->tcp_mss);
822		if (rwnd < tcp->tcp_mss)
823			rwnd = max_win;
824	}
825
826	/*
827	 * Record high water mark, this is used for flow-control
828	 * purposes in tcp_fuse_output().
829	 */
830	tcp->tcp_connp->conn_rcvbuf = rwnd;
831	tcp->tcp_rwnd = rwnd;
832	return (rwnd);
833}
834
835/*
836 * Calculate the maximum outstanding unread data block for a fused tcp endpoint.
837 */
838int
839tcp_fuse_maxpsz(tcp_t *tcp)
840{
841	tcp_t *peer_tcp = tcp->tcp_loopback_peer;
842	conn_t *connp = tcp->tcp_connp;
843	uint_t sndbuf = connp->conn_sndbuf;
844	uint_t maxpsz = sndbuf;
845
846	ASSERT(tcp->tcp_fused);
847	ASSERT(peer_tcp != NULL);
848	ASSERT(peer_tcp->tcp_connp->conn_rcvbuf != 0);
849	/*
850	 * In the fused loopback case, we want the stream head to split
851	 * up larger writes into smaller chunks for a more accurate flow-
852	 * control accounting.  Our maxpsz is half of the sender's send
853	 * buffer or the receiver's receive buffer, whichever is smaller.
854	 * We round up the buffer to system page size due to the lack of
855	 * TCP MSS concept in Fusion.
856	 */
857	if (maxpsz > peer_tcp->tcp_connp->conn_rcvbuf)
858		maxpsz = peer_tcp->tcp_connp->conn_rcvbuf;
859	maxpsz = P2ROUNDUP_TYPED(maxpsz, PAGESIZE, uint_t) >> 1;
860
861	return (maxpsz);
862}
863
864/*
865 * Called to release flow control.
866 */
867void
868tcp_fuse_backenable(tcp_t *tcp)
869{
870	tcp_t *peer_tcp = tcp->tcp_loopback_peer;
871
872	ASSERT(tcp->tcp_fused);
873	ASSERT(peer_tcp != NULL && peer_tcp->tcp_fused);
874	ASSERT(peer_tcp->tcp_loopback_peer == tcp);
875	ASSERT(!TCP_IS_DETACHED(tcp));
876	ASSERT(tcp->tcp_connp->conn_sqp ==
877	    peer_tcp->tcp_connp->conn_sqp);
878
879	if (tcp->tcp_rcv_list != NULL)
880		(void) tcp_fuse_rcv_drain(tcp->tcp_connp->conn_rq, tcp, NULL);
881
882	mutex_enter(&peer_tcp->tcp_non_sq_lock);
883	if (peer_tcp->tcp_flow_stopped &&
884	    (TCP_UNSENT_BYTES(peer_tcp) <=
885	    peer_tcp->tcp_connp->conn_sndlowat)) {
886		tcp_clrqfull(peer_tcp);
887	}
888	mutex_exit(&peer_tcp->tcp_non_sq_lock);
889
890	TCP_STAT(tcp->tcp_tcps, tcp_fusion_backenabled);
891}
892