Update to per-CPU hardware resources format.
[dragonfly.git] / sys / netinet / tcp_sack.c
CommitLineData
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1/*
2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved.
4 *
5 * This code is derived from software contributed to The DragonFly Project
6 * by Jeffrey M. Hsu.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
12f68b86 33 * $DragonFly: src/sys/netinet/tcp_sack.c,v 1.8 2008/08/15 21:37:16 nth Exp $
91489f6b
JH
34 */
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/kernel.h>
39#include <sys/malloc.h>
40#include <sys/queue.h>
41#include <sys/thread.h>
42#include <sys/types.h>
43#include <sys/socket.h>
44#include <sys/socketvar.h>
45
46#include <net/if.h>
47
48#include <netinet/in.h>
49#include <netinet/in_systm.h>
50#include <netinet/ip.h>
51#include <netinet/in_var.h>
52#include <netinet/in_pcb.h>
53#include <netinet/ip_var.h>
54#include <netinet/tcp.h>
55#include <netinet/tcp_seq.h>
56#include <netinet/tcp_var.h>
57
bf55dc6d
SZ
58/*
59 * Implemented:
60 *
61 * RFC 2018
62 * RFC 2883
63 * RFC 3517
64 */
65
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66struct sackblock {
67 tcp_seq sblk_start;
68 tcp_seq sblk_end;
69 TAILQ_ENTRY(sackblock) sblk_list;
70};
71
72#define MAXSAVEDBLOCKS 8 /* per connection limit */
73
01d244e6
SZ
74static int insert_block(struct scoreboard *scb,
75 const struct raw_sackblock *raw_sb);
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76static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una,
77 u_int maxseg);
78
12f68b86 79static MALLOC_DEFINE(M_SACKBLOCK, "sblk", "sackblock struct");
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80
81/*
82 * Per-tcpcb initialization.
83 */
84void
85tcp_sack_tcpcb_init(struct tcpcb *tp)
86{
87 struct scoreboard *scb = &tp->scb;
88
89 scb->nblocks = 0;
90 TAILQ_INIT(&scb->sackblocks);
91 scb->lastfound = NULL;
92}
93
94/*
95 * Find the SACK block containing or immediately preceding "seq".
96 * The boolean result indicates whether the sequence is actually
97 * contained in the SACK block.
98 */
99static boolean_t
100sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb)
101{
102 struct sackblock *hint = scb->lastfound;
103 struct sackblock *cur, *last, *prev;
104
105 if (TAILQ_EMPTY(&scb->sackblocks)) {
106 *sb = NULL;
107 return FALSE;
108 }
109
110 if (hint == NULL) {
111 /* No hint. Search from start to end. */
112 cur = TAILQ_FIRST(&scb->sackblocks);
113 last = NULL;
114 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list);
115 } else {
116 if (SEQ_GEQ(seq, hint->sblk_start)) {
117 /* Search from hint to end of list. */
118 cur = hint;
119 last = NULL;
120 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list);
121 } else {
122 /* Search from front of list to hint. */
123 cur = TAILQ_FIRST(&scb->sackblocks);
124 last = hint;
125 prev = TAILQ_PREV(hint, sackblock_list, sblk_list);
126 }
127 }
128
129 do {
130 if (SEQ_GT(cur->sblk_end, seq)) {
131 if (SEQ_GEQ(seq, cur->sblk_start)) {
132 *sb = scb->lastfound = cur;
133 return TRUE;
134 } else {
135 *sb = scb->lastfound =
136 TAILQ_PREV(cur, sackblock_list, sblk_list);
137 return FALSE;
138 }
139 }
140 cur = TAILQ_NEXT(cur, sblk_list);
141 } while (cur != last);
142
143 *sb = scb->lastfound = prev;
144 return FALSE;
145}
146
147/*
148 * Allocate a SACK block.
149 */
150static __inline struct sackblock *
006af0db 151alloc_sackblock(struct scoreboard *scb, const struct raw_sackblock *raw_sb)
91489f6b 152{
26d3f1fb
SZ
153 struct sackblock *sb;
154
006af0db
SZ
155 if (scb->freecache != NULL) {
156 sb = scb->freecache;
157 scb->freecache = NULL;
158 tcpstat.tcps_sacksbfast++;
01d244e6 159 } else {
006af0db
SZ
160 sb = kmalloc(sizeof(struct sackblock), M_SACKBLOCK, M_NOWAIT);
161 if (sb == NULL) {
162 tcpstat.tcps_sacksbfailed++;
163 return NULL;
164 }
26d3f1fb 165 }
006af0db
SZ
166 sb->sblk_start = raw_sb->rblk_start;
167 sb->sblk_end = raw_sb->rblk_end;
26d3f1fb 168 return sb;
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169}
170
01d244e6
SZ
171static __inline struct sackblock *
172alloc_sackblock_limit(struct scoreboard *scb,
173 const struct raw_sackblock *raw_sb)
174{
175 if (scb->nblocks == MAXSAVEDBLOCKS) {
176 /*
177 * Should try to kick out older blocks XXX JH
178 * May be able to coalesce with existing block.
179 * Or, go other way and free all blocks if we hit
180 * this limit.
181 */
182 tcpstat.tcps_sacksboverflow++;
183 return NULL;
184 }
006af0db 185 return alloc_sackblock(scb, raw_sb);
01d244e6
SZ
186}
187
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188/*
189 * Free a SACK block.
190 */
191static __inline void
006af0db 192free_sackblock(struct scoreboard *scb, struct sackblock *s)
91489f6b 193{
006af0db
SZ
194 if (scb->freecache == NULL) {
195 /* YYY Maybe use the latest freed block? */
196 scb->freecache = s;
197 return;
198 }
12f68b86 199 kfree(s, M_SACKBLOCK);
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200}
201
202/*
203 * Free up SACK blocks for data that's been acked.
204 */
205static void
206tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack)
207{
208 struct sackblock *sb, *nb;
209
210 sb = TAILQ_FIRST(&scb->sackblocks);
211 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) {
212 nb = TAILQ_NEXT(sb, sblk_list);
9e3d6c96 213 if (scb->lastfound == sb)
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214 scb->lastfound = NULL;
215 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
006af0db 216 free_sackblock(scb, sb);
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217 --scb->nblocks;
218 KASSERT(scb->nblocks >= 0,
219 ("SACK block count underflow: %d < 0", scb->nblocks));
220 sb = nb;
221 }
222 if (sb && SEQ_GT(th_ack, sb->sblk_start))
223 sb->sblk_start = th_ack; /* other side reneged? XXX */
224}
225
226/*
227 * Delete and free SACK blocks saved in scoreboard.
228 */
229void
230tcp_sack_cleanup(struct scoreboard *scb)
231{
232 struct sackblock *sb, *nb;
233
234 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) {
006af0db 235 free_sackblock(scb, sb);
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JH
236 --scb->nblocks;
237 }
238 KASSERT(scb->nblocks == 0,
239 ("SACK block %d count not zero", scb->nblocks));
240 TAILQ_INIT(&scb->sackblocks);
241 scb->lastfound = NULL;
242}
243
006af0db
SZ
244/*
245 * Delete and free SACK blocks saved in scoreboard.
246 * Delete the one slot block cache.
247 */
248void
249tcp_sack_destroy(struct scoreboard *scb)
250{
251 tcp_sack_cleanup(scb);
252 if (scb->freecache != NULL) {
253 kfree(scb->freecache, M_SACKBLOCK);
254 scb->freecache = NULL;
255 }
256}
257
d58ca578
SZ
258/*
259 * Cleanup the reported SACK block information
260 */
261void
262tcp_sack_report_cleanup(struct tcpcb *tp)
263{
264 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT);
265 tp->reportblk.rblk_start = tp->reportblk.rblk_end;
266}
267
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JH
268/*
269 * Returns 0 if not D-SACK block,
270 * 1 if D-SACK,
271 * 2 if duplicate of out-of-order D-SACK block.
272 */
273int
274tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks,
275 tcp_seq snd_una)
276{
277 if (numblocks == 0)
278 return 0;
279
280 if (SEQ_LT(blocks[0].rblk_start, snd_una))
281 return 1;
282
283 /* block 0 inside block 1 */
284 if (numblocks > 1 &&
285 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) &&
286 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end))
287 return 2;
288
289 return 0;
290}
291
292/*
293 * Update scoreboard on new incoming ACK.
294 */
295static void
296tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to)
297{
298 const int numblocks = to->to_nsackblocks;
299 struct raw_sackblock *blocks = to->to_sackblocks;
300 struct scoreboard *scb = &tp->scb;
91489f6b
JH
301 int startblock;
302 int i;
303
304 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0)
305 startblock = 1;
306 else
307 startblock = 0;
308
309 for (i = startblock; i < numblocks; i++) {
310 struct raw_sackblock *newsackblock = &blocks[i];
311
312 /* don't accept bad SACK blocks */
02cc2f35
SZ
313 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) {
314 tcpstat.tcps_rcvbadsackopt++;
91489f6b 315 break; /* skip all other blocks */
02cc2f35
SZ
316 }
317 tcpstat.tcps_sacksbupdate++;
91489f6b 318
01d244e6
SZ
319 if (insert_block(scb, newsackblock))
320 break;
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JH
321 }
322}
323
324void
325tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to)
326{
327 struct scoreboard *scb = &tp->scb;
a098966f 328 int rexmt_high_update = 0;
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329
330 tcp_sack_ack_blocks(scb, tp->snd_una);
331 tcp_sack_add_blocks(tp, to);
332 update_lostseq(scb, tp->snd_una, tp->t_maxseg);
a098966f 333 if (SEQ_LT(tp->rexmt_high, tp->snd_una)) {
91489f6b 334 tp->rexmt_high = tp->snd_una;
a098966f
SZ
335 rexmt_high_update = 1;
336 }
337 if (tp->t_flags & TF_SACKRESCUED) {
338 if (SEQ_LT(tp->rexmt_rescue, tp->snd_una)) {
339 tp->t_flags &= ~TF_SACKRESCUED;
340 } else if (rexmt_high_update &&
341 SEQ_LT(tp->rexmt_rescue, tp->rexmt_high)) {
342 /* Drag RescueRxt along with HighRxt */
343 tp->rexmt_rescue = tp->rexmt_high;
344 }
345 }
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JH
346}
347
348/*
349 * Insert SACK block into sender's scoreboard.
350 */
01d244e6
SZ
351static int
352insert_block(struct scoreboard *scb, const struct raw_sackblock *raw_sb)
91489f6b
JH
353{
354 struct sackblock *sb, *workingblock;
355 boolean_t overlap_front;
356
2ed615e0 357 if (TAILQ_EMPTY(&scb->sackblocks)) {
01d244e6
SZ
358 struct sackblock *newblock;
359
2ed615e0 360 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks"));
01d244e6 361
006af0db 362 newblock = alloc_sackblock(scb, raw_sb);
01d244e6
SZ
363 if (newblock == NULL)
364 return ENOMEM;
2ed615e0 365 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list);
01d244e6
SZ
366 scb->nblocks = 1;
367 return 0;
2ed615e0 368 }
91489f6b 369
01d244e6
SZ
370 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks"));
371 KASSERT(scb->nblocks <= MAXSAVEDBLOCKS,
91489f6b
JH
372 ("too many SACK blocks %d", scb->nblocks));
373
01d244e6 374 overlap_front = sack_block_lookup(scb, raw_sb->rblk_start, &sb);
91489f6b
JH
375
376 if (sb == NULL) {
01d244e6
SZ
377 workingblock = alloc_sackblock_limit(scb, raw_sb);
378 if (workingblock == NULL)
379 return ENOMEM;
380 TAILQ_INSERT_HEAD(&scb->sackblocks, workingblock, sblk_list);
91489f6b
JH
381 ++scb->nblocks;
382 } else {
01d244e6
SZ
383 if (overlap_front || sb->sblk_end == raw_sb->rblk_start) {
384 /* Extend old block */
91489f6b 385 workingblock = sb;
01d244e6
SZ
386 if (SEQ_GT(raw_sb->rblk_end, sb->sblk_end))
387 sb->sblk_end = raw_sb->rblk_end;
02cc2f35 388 tcpstat.tcps_sacksbreused++;
91489f6b 389 } else {
01d244e6
SZ
390 workingblock = alloc_sackblock_limit(scb, raw_sb);
391 if (workingblock == NULL)
392 return ENOMEM;
393 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, workingblock,
394 sblk_list);
91489f6b
JH
395 ++scb->nblocks;
396 }
397 }
398
399 /* Consolidate right-hand side. */
400 sb = TAILQ_NEXT(workingblock, sblk_list);
401 while (sb != NULL &&
402 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) {
403 struct sackblock *nextblock;
404
405 nextblock = TAILQ_NEXT(sb, sblk_list);
9e3d6c96
MD
406 if (scb->lastfound == sb)
407 scb->lastfound = NULL;
91489f6b
JH
408 /* Remove completely overlapped block */
409 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
006af0db 410 free_sackblock(scb, sb);
91489f6b
JH
411 --scb->nblocks;
412 KASSERT(scb->nblocks > 0,
413 ("removed overlapped block: %d blocks left", scb->nblocks));
414 sb = nextblock;
415 }
416 if (sb != NULL &&
417 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) {
418 /* Extend new block to cover partially overlapped old block. */
419 workingblock->sblk_end = sb->sblk_end;
9e3d6c96
MD
420 if (scb->lastfound == sb)
421 scb->lastfound = NULL;
91489f6b 422 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
006af0db 423 free_sackblock(scb, sb);
91489f6b
JH
424 --scb->nblocks;
425 KASSERT(scb->nblocks > 0,
426 ("removed partial right: %d blocks left", scb->nblocks));
427 }
01d244e6 428 return 0;
91489f6b
JH
429}
430
431#ifdef DEBUG_SACK_BLOCKS
432static void
433tcp_sack_dump_blocks(struct scoreboard *scb)
434{
435 struct sackblock *sb;
436
a6ec04bc 437 kprintf("%d blocks:", scb->nblocks);
91489f6b 438 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
a6ec04bc
SW
439 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end);
440 kprintf("\n");
91489f6b
JH
441}
442#else
443static __inline void
444tcp_sack_dump_blocks(struct scoreboard *scb)
445{
446}
447#endif
448
449/*
450 * Optimization to quickly determine which packets are lost.
451 */
452static void
453update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg)
454{
455 struct sackblock *sb;
456 int nsackblocks = 0;
457 int bytes_sacked = 0;
458
459 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list);
460 while (sb != NULL) {
461 ++nsackblocks;
462 bytes_sacked += sb->sblk_end - sb->sblk_start;
463 if (nsackblocks == tcprexmtthresh ||
464 bytes_sacked >= tcprexmtthresh * maxseg) {
465 scb->lostseq = sb->sblk_start;
466 return;
467 }
468 sb = TAILQ_PREV(sb, sackblock_list, sblk_list);
469 }
470 scb->lostseq = snd_una;
471}
472
473/*
474 * Return whether the given sequence number is considered lost.
475 */
476static boolean_t
477scb_islost(struct scoreboard *scb, tcp_seq seqnum)
478{
479 return SEQ_LT(seqnum, scb->lostseq);
480}
481
482/*
483 * True if at least "amount" has been SACKed. Used by Early Retransmit.
484 */
485boolean_t
486tcp_sack_has_sacked(struct scoreboard *scb, u_int amount)
487{
488 struct sackblock *sb;
489 int bytes_sacked = 0;
490
491 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
492 bytes_sacked += sb->sblk_end - sb->sblk_start;
493 if (bytes_sacked >= amount)
494 return TRUE;
495 }
496 return FALSE;
497}
498
9a5b142f
JH
499/*
500 * Number of bytes SACKed below seq.
501 */
502int
503tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq)
504{
505 struct sackblock *sb;
506 int bytes_sacked = 0;
507
508 sb = TAILQ_FIRST(&scb->sackblocks);
509 while (sb && SEQ_GT(seq, sb->sblk_start)) {
510 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start;
511 sb = TAILQ_NEXT(sb, sblk_list);
512 }
513 return bytes_sacked;
514}
515
91489f6b
JH
516/*
517 * Return estimate of the number of bytes outstanding in the network.
518 */
519uint32_t
520tcp_sack_compute_pipe(struct tcpcb *tp)
521{
522 struct scoreboard *scb = &tp->scb;
523 struct sackblock *sb;
524 int nlost, nretransmitted;
525 tcp_seq end;
526
527 nlost = tp->snd_max - scb->lostseq;
528 nretransmitted = tp->rexmt_high - tp->snd_una;
529
530 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
531 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) {
532 end = seq_min(sb->sblk_end, tp->rexmt_high);
533 nretransmitted -= end - sb->sblk_start;
534 }
535 if (SEQ_GEQ(sb->sblk_start, scb->lostseq))
536 nlost -= sb->sblk_end - sb->sblk_start;
537 }
538
539 return (nlost + nretransmitted);
540}
541
542/*
543 * Return the sequence number and length of the next segment to transmit
544 * when in Fast Recovery.
545 */
546boolean_t
547tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen,
1bdfd728 548 boolean_t *rescue)
91489f6b
JH
549{
550 struct scoreboard *scb = &tp->scb;
551 struct socket *so = tp->t_inpcb->inp_socket;
552 struct sackblock *sb;
553 const struct sackblock *lastblock =
554 TAILQ_LAST(&scb->sackblocks, sackblock_list);
555 tcp_seq torexmt;
556 long len, off;
557
558 /* skip SACKed data */
559 tcp_sack_skip_sacked(scb, &tp->rexmt_high);
560
561 /* Look for lost data. */
562 torexmt = tp->rexmt_high;
1bdfd728 563 *rescue = FALSE;
91489f6b
JH
564 if (lastblock != NULL) {
565 if (SEQ_LT(torexmt, lastblock->sblk_end) &&
566 scb_islost(scb, torexmt)) {
567sendunsacked:
568 *nextrexmt = torexmt;
569 /* If the left-hand edge has been SACKed, pull it in. */
570 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb))
571 *plen = sb->sblk_start - torexmt;
572 else
573 *plen = tp->t_maxseg;
574 return TRUE;
575 }
576 }
577
578 /* See if unsent data available within send window. */
579 off = tp->snd_max - tp->snd_una;
6d49aa6f 580 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off;
91489f6b
JH
581 if (len > 0) {
582 *nextrexmt = tp->snd_max; /* Send new data. */
583 *plen = tp->t_maxseg;
584 return TRUE;
585 }
586
587 /* We're less certain this data has been lost. */
1bdfd728 588 if (lastblock != NULL && SEQ_LT(torexmt, lastblock->sblk_end))
91489f6b
JH
589 goto sendunsacked;
590
a098966f 591 /* Rescue retransmission */
1bdfd728
SZ
592 if (tcp_do_rescuesack) {
593 tcpstat.tcps_sackrescue_try++;
a098966f
SZ
594 if (tp->t_flags & TF_SACKRESCUED) {
595 if (!tcp_aggressive_rescuesack)
596 return FALSE;
1bdfd728 597
a098966f
SZ
598 /*
599 * Aggressive variant of the rescue retransmission.
600 *
601 * The idea of the rescue retransmission is to sustain
602 * the ACK clock thus to avoid timeout retransmission.
603 *
604 * Under some situations, the conservative approach
605 * suggested in the draft
606 * http://tools.ietf.org/html/
607 * draft-nishida-tcpm-rescue-retransmission-00
608 * could not sustain ACK clock, since it only allows
609 * one rescue retransmission before a cumulative ACK
610 * covers the segement transmitted by rescue
611 * retransmission.
612 *
613 * We try to locate the next unSACKed segment which
614 * follows the previously sent rescue segment. If
615 * there is no such segment, we loop back to the first
616 * unacknowledged segment.
617 */
618
619 /*
620 * Skip SACKed data, but here we follow
621 * the last transmitted rescue segment.
622 */
623 torexmt = tp->rexmt_rescue;
624 tcp_sack_skip_sacked(scb, &torexmt);
625 if (torexmt == tp->snd_max) {
626 /* Nothing left to retransmit; restart */
627 torexmt = tp->snd_una;
628 }
629 }
1bdfd728 630 *rescue = TRUE;
1bdfd728
SZ
631 goto sendunsacked;
632 } else if (tcp_do_smartsack && lastblock == NULL) {
a098966f
SZ
633 tcpstat.tcps_sackrescue_try++;
634 *rescue = TRUE;
1bdfd728
SZ
635 goto sendunsacked;
636 }
637
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638 return FALSE;
639}
640
641/*
642 * Return the next sequence number higher than "*prexmt" that has
643 * not been SACKed.
644 */
645void
646tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt)
647{
648 struct sackblock *sb;
649
650 /* skip SACKed data */
651 if (sack_block_lookup(scb, *prexmt, &sb))
652 *prexmt = sb->sblk_end;
653}
654
655#ifdef later
656void
657tcp_sack_save_scoreboard(struct scoreboard *scb)
658{
659 struct scoreboard *scb = &tp->scb;
660
661 scb->sackblocks_prev = scb->sackblocks;
662 TAILQ_INIT(&scb->sackblocks);
663}
664
665void
666tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
667 u_int maxseg)
668{
669 struct sackblock *sb;
670
671 scb->sackblocks = scb->sackblocks_prev;
672 scb->nblocks = 0;
673 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
674 ++scb->nblocks;
675 tcp_sack_ack_blocks(scb, snd_una);
676 scb->lastfound = NULL;
677}
678#endif
679
680#ifdef DEBUG_SACK_HISTORY
681static void
682tcp_sack_dump_history(char *msg, struct tcpcb *tp)
683{
684 int i;
685 static int ndumped;
686
687 /* only need a couple of these to debug most problems */
688 if (++ndumped > 900)
689 return;
690
a6ec04bc 691 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory);
91489f6b 692 for (i = 0; i < tp->nsackhistory; ++i)
a6ec04bc 693 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start,
91489f6b 694 tp->sackhistory[i].rblk_end);
a6ec04bc 695 kprintf("\n");
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696}
697#else
698static __inline void
699tcp_sack_dump_history(char *msg, struct tcpcb *tp)
700{
701}
702#endif
703
704/*
705 * Remove old SACK blocks from the SACK history that have already been ACKed.
706 */
707static void
708tcp_sack_ack_history(struct tcpcb *tp)
709{
710 int i, nblocks, openslot;
711
712 tcp_sack_dump_history("before tcp_sack_ack_history", tp);
713 nblocks = tp->nsackhistory;
714 for (i = openslot = 0; i < nblocks; ++i) {
715 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) {
716 --tp->nsackhistory;
717 continue;
718 }
719 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt))
720 tp->sackhistory[i].rblk_start = tp->rcv_nxt;
721 if (i == openslot)
722 ++openslot;
723 else
724 tp->sackhistory[openslot++] = tp->sackhistory[i];
725 }
726 tcp_sack_dump_history("after tcp_sack_ack_history", tp);
727 KASSERT(openslot == tp->nsackhistory,
728 ("tcp_sack_ack_history miscounted: %d != %d",
729 openslot, tp->nsackhistory));
730}
731
732/*
733 * Add or merge newblock into reported history.
734 * Also remove or update SACK blocks that will be acked.
735 */
736static void
737tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end)
738{
739 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS];
740 int i, cindex;
741
742 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp);
743 /*
744 * Six cases:
745 * 0) no overlap
746 * 1) newblock == oldblock
747 * 2) oldblock contains newblock
748 * 3) newblock contains oldblock
749 * 4) tail of oldblock overlaps or abuts start of newblock
750 * 5) tail of newblock overlaps or abuts head of oldblock
751 */
752 for (i = cindex = 0; i < tp->nsackhistory; ++i) {
753 struct raw_sackblock *oldblock = &tp->sackhistory[i];
754 tcp_seq old_start = oldblock->rblk_start;
755 tcp_seq old_end = oldblock->rblk_end;
756
757 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) {
758 /* Case 0: no overlap. Copy old block. */
759 copy[cindex++] = *oldblock;
760 continue;
761 }
762
763 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) {
764 /* Cases 1 & 2. Move block to front of history. */
765 int j;
766
767 start = old_start;
768 end = old_end;
769 /* no need to check rest of blocks */
770 for (j = i + 1; j < tp->nsackhistory; ++j)
771 copy[cindex++] = tp->sackhistory[j];
772 break;
773 }
774
775 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) {
776 /* Case 4: extend start of new block. */
777 start = old_start;
778 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) {
779 /* Case 5: extend end of new block */
780 end = old_end;
781 } else {
782 /* Case 3. Delete old block by not copying it. */
783 KASSERT(SEQ_LEQ(start, old_start) &&
784 SEQ_GEQ(end, old_end),
785 ("bad logic: old [%u, %u), new [%u, %u)",
786 old_start, old_end, start, end));
787 }
788 }
789
790 /* insert new block */
791 tp->sackhistory[0].rblk_start = start;
792 tp->sackhistory[0].rblk_end = end;
793 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1);
794 for (i = 0; i < cindex; ++i)
795 tp->sackhistory[i + 1] = copy[i];
796 tp->nsackhistory = cindex + 1;
797 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp);
798}
799
800/*
801 * Fill in SACK report to return to data sender.
802 */
803void
804tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen)
805{
806 u_int optlen = *plen;
807 uint32_t *lp = (uint32_t *)(opt + optlen);
808 uint32_t *olp;
809 tcp_seq hstart = tp->rcv_nxt, hend;
810 int nblocks;
811
812 KASSERT(TCP_MAXOLEN - optlen >=
813 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK,
814 ("no room for SACK header and one block: optlen %d", optlen));
815
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816 if (tp->t_flags & TF_DUPSEG)
817 tcpstat.tcps_snddsackopt++;
818 else
819 tcpstat.tcps_sndsackopt++;
820
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821 olp = lp++;
822 optlen += TCPOLEN_SACK_ALIGNED;
823
824 tcp_sack_ack_history(tp);
825 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) {
826 *lp++ = htonl(tp->reportblk.rblk_start);
827 *lp++ = htonl(tp->reportblk.rblk_end);
828 optlen += TCPOLEN_SACK_BLOCK;
829 hstart = tp->reportblk.rblk_start;
830 hend = tp->reportblk.rblk_end;
831 if (tp->t_flags & TF_ENCLOSESEG) {
832 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK,
833 ("no room for enclosing SACK block: oplen %d",
834 optlen));
835 *lp++ = htonl(tp->encloseblk.rblk_start);
836 *lp++ = htonl(tp->encloseblk.rblk_end);
837 optlen += TCPOLEN_SACK_BLOCK;
838 hstart = tp->encloseblk.rblk_start;
839 hend = tp->encloseblk.rblk_end;
840 }
841 if (SEQ_GT(hstart, tp->rcv_nxt))
842 tcp_sack_update_reported_history(tp, hstart, hend);
843 }
844 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) {
845 /* Fill in from left! Walk re-assembly queue. */
846 struct tseg_qent *q;
847
848 q = LIST_FIRST(&tp->t_segq);
849 while (q != NULL &&
850 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
851 *lp++ = htonl(q->tqe_th->th_seq);
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852 *lp++ = htonl(TCP_SACK_BLKEND(
853 q->tqe_th->th_seq + q->tqe_len,
854 q->tqe_th->th_flags));
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855 optlen += TCPOLEN_SACK_BLOCK;
856 q = LIST_NEXT(q, tqe_q);
857 }
858 } else {
859 int n = 0;
860
861 /* Fill in SACK blocks from right side. */
862 while (n < tp->nsackhistory &&
863 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
864 if (tp->sackhistory[n].rblk_start != hstart) {
865 *lp++ = htonl(tp->sackhistory[n].rblk_start);
866 *lp++ = htonl(tp->sackhistory[n].rblk_end);
867 optlen += TCPOLEN_SACK_BLOCK;
868 }
869 ++n;
870 }
871 }
872 tp->reportblk.rblk_start = tp->reportblk.rblk_end;
873 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT);
874 nblocks = (lp - olp - 1) / 2;
875 *olp = htonl(TCPOPT_SACK_ALIGNED |
876 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK));
877 *plen = optlen;
878}