tcp/sack: Take FIN bit into consideration when setup report SACK block end
[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 $
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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
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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
74static void insert_block(struct scoreboard *scb, struct sackblock *newblock);
75static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una,
76 u_int maxseg);
77
12f68b86 78static MALLOC_DEFINE(M_SACKBLOCK, "sblk", "sackblock struct");
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79
80/*
81 * Per-tcpcb initialization.
82 */
83void
84tcp_sack_tcpcb_init(struct tcpcb *tp)
85{
86 struct scoreboard *scb = &tp->scb;
87
88 scb->nblocks = 0;
89 TAILQ_INIT(&scb->sackblocks);
90 scb->lastfound = NULL;
91}
92
93/*
94 * Find the SACK block containing or immediately preceding "seq".
95 * The boolean result indicates whether the sequence is actually
96 * contained in the SACK block.
97 */
98static boolean_t
99sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb)
100{
101 struct sackblock *hint = scb->lastfound;
102 struct sackblock *cur, *last, *prev;
103
104 if (TAILQ_EMPTY(&scb->sackblocks)) {
105 *sb = NULL;
106 return FALSE;
107 }
108
109 if (hint == NULL) {
110 /* No hint. Search from start to end. */
111 cur = TAILQ_FIRST(&scb->sackblocks);
112 last = NULL;
113 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list);
114 } else {
115 if (SEQ_GEQ(seq, hint->sblk_start)) {
116 /* Search from hint to end of list. */
117 cur = hint;
118 last = NULL;
119 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list);
120 } else {
121 /* Search from front of list to hint. */
122 cur = TAILQ_FIRST(&scb->sackblocks);
123 last = hint;
124 prev = TAILQ_PREV(hint, sackblock_list, sblk_list);
125 }
126 }
127
128 do {
129 if (SEQ_GT(cur->sblk_end, seq)) {
130 if (SEQ_GEQ(seq, cur->sblk_start)) {
131 *sb = scb->lastfound = cur;
132 return TRUE;
133 } else {
134 *sb = scb->lastfound =
135 TAILQ_PREV(cur, sackblock_list, sblk_list);
136 return FALSE;
137 }
138 }
139 cur = TAILQ_NEXT(cur, sblk_list);
140 } while (cur != last);
141
142 *sb = scb->lastfound = prev;
143 return FALSE;
144}
145
146/*
147 * Allocate a SACK block.
148 */
149static __inline struct sackblock *
150alloc_sackblock(void)
151{
12f68b86 152 return (kmalloc(sizeof(struct sackblock), M_SACKBLOCK, M_NOWAIT));
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153}
154
155/*
156 * Free a SACK block.
157 */
158static __inline void
159free_sackblock(struct sackblock *s)
160{
12f68b86 161 kfree(s, M_SACKBLOCK);
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162}
163
164/*
165 * Free up SACK blocks for data that's been acked.
166 */
167static void
168tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack)
169{
170 struct sackblock *sb, *nb;
171
172 sb = TAILQ_FIRST(&scb->sackblocks);
173 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) {
174 nb = TAILQ_NEXT(sb, sblk_list);
9e3d6c96 175 if (scb->lastfound == sb)
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176 scb->lastfound = NULL;
177 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
178 free_sackblock(sb);
179 --scb->nblocks;
180 KASSERT(scb->nblocks >= 0,
181 ("SACK block count underflow: %d < 0", scb->nblocks));
182 sb = nb;
183 }
184 if (sb && SEQ_GT(th_ack, sb->sblk_start))
185 sb->sblk_start = th_ack; /* other side reneged? XXX */
186}
187
188/*
189 * Delete and free SACK blocks saved in scoreboard.
190 */
191void
192tcp_sack_cleanup(struct scoreboard *scb)
193{
194 struct sackblock *sb, *nb;
195
196 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) {
197 free_sackblock(sb);
198 --scb->nblocks;
199 }
200 KASSERT(scb->nblocks == 0,
201 ("SACK block %d count not zero", scb->nblocks));
202 TAILQ_INIT(&scb->sackblocks);
203 scb->lastfound = NULL;
204}
205
206/*
207 * Returns 0 if not D-SACK block,
208 * 1 if D-SACK,
209 * 2 if duplicate of out-of-order D-SACK block.
210 */
211int
212tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks,
213 tcp_seq snd_una)
214{
215 if (numblocks == 0)
216 return 0;
217
218 if (SEQ_LT(blocks[0].rblk_start, snd_una))
219 return 1;
220
221 /* block 0 inside block 1 */
222 if (numblocks > 1 &&
223 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) &&
224 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end))
225 return 2;
226
227 return 0;
228}
229
230/*
231 * Update scoreboard on new incoming ACK.
232 */
233static void
234tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to)
235{
236 const int numblocks = to->to_nsackblocks;
237 struct raw_sackblock *blocks = to->to_sackblocks;
238 struct scoreboard *scb = &tp->scb;
239 struct sackblock *sb;
240 int startblock;
241 int i;
242
243 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0)
244 startblock = 1;
245 else
246 startblock = 0;
247
248 for (i = startblock; i < numblocks; i++) {
249 struct raw_sackblock *newsackblock = &blocks[i];
250
251 /* don't accept bad SACK blocks */
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252 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) {
253 tcpstat.tcps_rcvbadsackopt++;
91489f6b 254 break; /* skip all other blocks */
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255 }
256 tcpstat.tcps_sacksbupdate++;
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257
258 sb = alloc_sackblock();
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259 if (sb == NULL) { /* do some sort of cleanup? XXX */
260 tcpstat.tcps_sacksbfailed++;
91489f6b 261 break; /* just skip rest of blocks */
02cc2f35 262 }
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263 sb->sblk_start = newsackblock->rblk_start;
264 sb->sblk_end = newsackblock->rblk_end;
265 if (TAILQ_EMPTY(&scb->sackblocks)) {
266 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks"));
267 scb->nblocks = 1;
268 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list);
269 } else {
270 insert_block(scb, sb);
271 }
272 }
273}
274
275void
276tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to)
277{
278 struct scoreboard *scb = &tp->scb;
279
280 tcp_sack_ack_blocks(scb, tp->snd_una);
281 tcp_sack_add_blocks(tp, to);
282 update_lostseq(scb, tp->snd_una, tp->t_maxseg);
283 if (SEQ_LT(tp->rexmt_high, tp->snd_una))
284 tp->rexmt_high = tp->snd_una;
285}
286
287/*
288 * Insert SACK block into sender's scoreboard.
289 */
290static void
291insert_block(struct scoreboard *scb, struct sackblock *newblock)
292{
293 struct sackblock *sb, *workingblock;
294 boolean_t overlap_front;
295
296 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks"));
297
298 if (scb->nblocks == MAXSAVEDBLOCKS) {
299 /*
300 * Should try to kick out older blocks XXX JH
301 * May be able to coalesce with existing block.
302 * Or, go other way and free all blocks if we hit this limit.
303 */
304 free_sackblock(newblock);
02cc2f35 305 tcpstat.tcps_sacksboverflow++;
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306 return;
307 }
308 KASSERT(scb->nblocks < MAXSAVEDBLOCKS,
309 ("too many SACK blocks %d", scb->nblocks));
310
311 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb);
312
313 if (sb == NULL) {
314 workingblock = newblock;
315 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list);
316 ++scb->nblocks;
317 } else {
318 if (overlap_front || sb->sblk_end == newblock->sblk_start) {
319 /* extend old block and discard new one */
320 workingblock = sb;
321 if (SEQ_GT(newblock->sblk_end, sb->sblk_end))
322 sb->sblk_end = newblock->sblk_end;
323 free_sackblock(newblock);
02cc2f35 324 tcpstat.tcps_sacksbreused++;
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325 } else {
326 workingblock = newblock;
327 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock,
328 sblk_list);
329 ++scb->nblocks;
330 }
331 }
332
333 /* Consolidate right-hand side. */
334 sb = TAILQ_NEXT(workingblock, sblk_list);
335 while (sb != NULL &&
336 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) {
337 struct sackblock *nextblock;
338
339 nextblock = TAILQ_NEXT(sb, sblk_list);
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340 if (scb->lastfound == sb)
341 scb->lastfound = NULL;
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342 /* Remove completely overlapped block */
343 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
344 free_sackblock(sb);
345 --scb->nblocks;
346 KASSERT(scb->nblocks > 0,
347 ("removed overlapped block: %d blocks left", scb->nblocks));
348 sb = nextblock;
349 }
350 if (sb != NULL &&
351 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) {
352 /* Extend new block to cover partially overlapped old block. */
353 workingblock->sblk_end = sb->sblk_end;
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MD
354 if (scb->lastfound == sb)
355 scb->lastfound = NULL;
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356 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
357 free_sackblock(sb);
358 --scb->nblocks;
359 KASSERT(scb->nblocks > 0,
360 ("removed partial right: %d blocks left", scb->nblocks));
361 }
362}
363
364#ifdef DEBUG_SACK_BLOCKS
365static void
366tcp_sack_dump_blocks(struct scoreboard *scb)
367{
368 struct sackblock *sb;
369
a6ec04bc 370 kprintf("%d blocks:", scb->nblocks);
91489f6b 371 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
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372 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end);
373 kprintf("\n");
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374}
375#else
376static __inline void
377tcp_sack_dump_blocks(struct scoreboard *scb)
378{
379}
380#endif
381
382/*
383 * Optimization to quickly determine which packets are lost.
384 */
385static void
386update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg)
387{
388 struct sackblock *sb;
389 int nsackblocks = 0;
390 int bytes_sacked = 0;
391
392 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list);
393 while (sb != NULL) {
394 ++nsackblocks;
395 bytes_sacked += sb->sblk_end - sb->sblk_start;
396 if (nsackblocks == tcprexmtthresh ||
397 bytes_sacked >= tcprexmtthresh * maxseg) {
398 scb->lostseq = sb->sblk_start;
399 return;
400 }
401 sb = TAILQ_PREV(sb, sackblock_list, sblk_list);
402 }
403 scb->lostseq = snd_una;
404}
405
406/*
407 * Return whether the given sequence number is considered lost.
408 */
409static boolean_t
410scb_islost(struct scoreboard *scb, tcp_seq seqnum)
411{
412 return SEQ_LT(seqnum, scb->lostseq);
413}
414
415/*
416 * True if at least "amount" has been SACKed. Used by Early Retransmit.
417 */
418boolean_t
419tcp_sack_has_sacked(struct scoreboard *scb, u_int amount)
420{
421 struct sackblock *sb;
422 int bytes_sacked = 0;
423
424 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
425 bytes_sacked += sb->sblk_end - sb->sblk_start;
426 if (bytes_sacked >= amount)
427 return TRUE;
428 }
429 return FALSE;
430}
431
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432/*
433 * Number of bytes SACKed below seq.
434 */
435int
436tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq)
437{
438 struct sackblock *sb;
439 int bytes_sacked = 0;
440
441 sb = TAILQ_FIRST(&scb->sackblocks);
442 while (sb && SEQ_GT(seq, sb->sblk_start)) {
443 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start;
444 sb = TAILQ_NEXT(sb, sblk_list);
445 }
446 return bytes_sacked;
447}
448
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449/*
450 * Return estimate of the number of bytes outstanding in the network.
451 */
452uint32_t
453tcp_sack_compute_pipe(struct tcpcb *tp)
454{
455 struct scoreboard *scb = &tp->scb;
456 struct sackblock *sb;
457 int nlost, nretransmitted;
458 tcp_seq end;
459
460 nlost = tp->snd_max - scb->lostseq;
461 nretransmitted = tp->rexmt_high - tp->snd_una;
462
463 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
464 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) {
465 end = seq_min(sb->sblk_end, tp->rexmt_high);
466 nretransmitted -= end - sb->sblk_start;
467 }
468 if (SEQ_GEQ(sb->sblk_start, scb->lostseq))
469 nlost -= sb->sblk_end - sb->sblk_start;
470 }
471
472 return (nlost + nretransmitted);
473}
474
475/*
476 * Return the sequence number and length of the next segment to transmit
477 * when in Fast Recovery.
478 */
479boolean_t
480tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen,
481 boolean_t *lostdup)
482{
483 struct scoreboard *scb = &tp->scb;
484 struct socket *so = tp->t_inpcb->inp_socket;
485 struct sackblock *sb;
486 const struct sackblock *lastblock =
487 TAILQ_LAST(&scb->sackblocks, sackblock_list);
488 tcp_seq torexmt;
489 long len, off;
490
491 /* skip SACKed data */
492 tcp_sack_skip_sacked(scb, &tp->rexmt_high);
493
494 /* Look for lost data. */
495 torexmt = tp->rexmt_high;
496 *lostdup = FALSE;
497 if (lastblock != NULL) {
498 if (SEQ_LT(torexmt, lastblock->sblk_end) &&
499 scb_islost(scb, torexmt)) {
500sendunsacked:
501 *nextrexmt = torexmt;
502 /* If the left-hand edge has been SACKed, pull it in. */
503 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb))
504 *plen = sb->sblk_start - torexmt;
505 else
506 *plen = tp->t_maxseg;
507 return TRUE;
508 }
509 }
510
511 /* See if unsent data available within send window. */
512 off = tp->snd_max - tp->snd_una;
6d49aa6f 513 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off;
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514 if (len > 0) {
515 *nextrexmt = tp->snd_max; /* Send new data. */
516 *plen = tp->t_maxseg;
517 return TRUE;
518 }
519
520 /* We're less certain this data has been lost. */
521 if (lastblock == NULL || SEQ_LT(torexmt, lastblock->sblk_end))
522 goto sendunsacked;
523
524 return FALSE;
525}
526
527/*
528 * Return the next sequence number higher than "*prexmt" that has
529 * not been SACKed.
530 */
531void
532tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt)
533{
534 struct sackblock *sb;
535
536 /* skip SACKed data */
537 if (sack_block_lookup(scb, *prexmt, &sb))
538 *prexmt = sb->sblk_end;
539}
540
541#ifdef later
542void
543tcp_sack_save_scoreboard(struct scoreboard *scb)
544{
545 struct scoreboard *scb = &tp->scb;
546
547 scb->sackblocks_prev = scb->sackblocks;
548 TAILQ_INIT(&scb->sackblocks);
549}
550
551void
552tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
553 u_int maxseg)
554{
555 struct sackblock *sb;
556
557 scb->sackblocks = scb->sackblocks_prev;
558 scb->nblocks = 0;
559 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
560 ++scb->nblocks;
561 tcp_sack_ack_blocks(scb, snd_una);
562 scb->lastfound = NULL;
563}
564#endif
565
566#ifdef DEBUG_SACK_HISTORY
567static void
568tcp_sack_dump_history(char *msg, struct tcpcb *tp)
569{
570 int i;
571 static int ndumped;
572
573 /* only need a couple of these to debug most problems */
574 if (++ndumped > 900)
575 return;
576
a6ec04bc 577 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory);
91489f6b 578 for (i = 0; i < tp->nsackhistory; ++i)
a6ec04bc 579 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start,
91489f6b 580 tp->sackhistory[i].rblk_end);
a6ec04bc 581 kprintf("\n");
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JH
582}
583#else
584static __inline void
585tcp_sack_dump_history(char *msg, struct tcpcb *tp)
586{
587}
588#endif
589
590/*
591 * Remove old SACK blocks from the SACK history that have already been ACKed.
592 */
593static void
594tcp_sack_ack_history(struct tcpcb *tp)
595{
596 int i, nblocks, openslot;
597
598 tcp_sack_dump_history("before tcp_sack_ack_history", tp);
599 nblocks = tp->nsackhistory;
600 for (i = openslot = 0; i < nblocks; ++i) {
601 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) {
602 --tp->nsackhistory;
603 continue;
604 }
605 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt))
606 tp->sackhistory[i].rblk_start = tp->rcv_nxt;
607 if (i == openslot)
608 ++openslot;
609 else
610 tp->sackhistory[openslot++] = tp->sackhistory[i];
611 }
612 tcp_sack_dump_history("after tcp_sack_ack_history", tp);
613 KASSERT(openslot == tp->nsackhistory,
614 ("tcp_sack_ack_history miscounted: %d != %d",
615 openslot, tp->nsackhistory));
616}
617
618/*
619 * Add or merge newblock into reported history.
620 * Also remove or update SACK blocks that will be acked.
621 */
622static void
623tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end)
624{
625 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS];
626 int i, cindex;
627
628 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp);
629 /*
630 * Six cases:
631 * 0) no overlap
632 * 1) newblock == oldblock
633 * 2) oldblock contains newblock
634 * 3) newblock contains oldblock
635 * 4) tail of oldblock overlaps or abuts start of newblock
636 * 5) tail of newblock overlaps or abuts head of oldblock
637 */
638 for (i = cindex = 0; i < tp->nsackhistory; ++i) {
639 struct raw_sackblock *oldblock = &tp->sackhistory[i];
640 tcp_seq old_start = oldblock->rblk_start;
641 tcp_seq old_end = oldblock->rblk_end;
642
643 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) {
644 /* Case 0: no overlap. Copy old block. */
645 copy[cindex++] = *oldblock;
646 continue;
647 }
648
649 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) {
650 /* Cases 1 & 2. Move block to front of history. */
651 int j;
652
653 start = old_start;
654 end = old_end;
655 /* no need to check rest of blocks */
656 for (j = i + 1; j < tp->nsackhistory; ++j)
657 copy[cindex++] = tp->sackhistory[j];
658 break;
659 }
660
661 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) {
662 /* Case 4: extend start of new block. */
663 start = old_start;
664 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) {
665 /* Case 5: extend end of new block */
666 end = old_end;
667 } else {
668 /* Case 3. Delete old block by not copying it. */
669 KASSERT(SEQ_LEQ(start, old_start) &&
670 SEQ_GEQ(end, old_end),
671 ("bad logic: old [%u, %u), new [%u, %u)",
672 old_start, old_end, start, end));
673 }
674 }
675
676 /* insert new block */
677 tp->sackhistory[0].rblk_start = start;
678 tp->sackhistory[0].rblk_end = end;
679 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1);
680 for (i = 0; i < cindex; ++i)
681 tp->sackhistory[i + 1] = copy[i];
682 tp->nsackhistory = cindex + 1;
683 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp);
684}
685
686/*
687 * Fill in SACK report to return to data sender.
688 */
689void
690tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen)
691{
692 u_int optlen = *plen;
693 uint32_t *lp = (uint32_t *)(opt + optlen);
694 uint32_t *olp;
695 tcp_seq hstart = tp->rcv_nxt, hend;
696 int nblocks;
697
698 KASSERT(TCP_MAXOLEN - optlen >=
699 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK,
700 ("no room for SACK header and one block: optlen %d", optlen));
701
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702 if (tp->t_flags & TF_DUPSEG)
703 tcpstat.tcps_snddsackopt++;
704 else
705 tcpstat.tcps_sndsackopt++;
706
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707 olp = lp++;
708 optlen += TCPOLEN_SACK_ALIGNED;
709
710 tcp_sack_ack_history(tp);
711 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) {
712 *lp++ = htonl(tp->reportblk.rblk_start);
713 *lp++ = htonl(tp->reportblk.rblk_end);
714 optlen += TCPOLEN_SACK_BLOCK;
715 hstart = tp->reportblk.rblk_start;
716 hend = tp->reportblk.rblk_end;
717 if (tp->t_flags & TF_ENCLOSESEG) {
718 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK,
719 ("no room for enclosing SACK block: oplen %d",
720 optlen));
721 *lp++ = htonl(tp->encloseblk.rblk_start);
722 *lp++ = htonl(tp->encloseblk.rblk_end);
723 optlen += TCPOLEN_SACK_BLOCK;
724 hstart = tp->encloseblk.rblk_start;
725 hend = tp->encloseblk.rblk_end;
726 }
727 if (SEQ_GT(hstart, tp->rcv_nxt))
728 tcp_sack_update_reported_history(tp, hstart, hend);
729 }
730 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) {
731 /* Fill in from left! Walk re-assembly queue. */
732 struct tseg_qent *q;
733
734 q = LIST_FIRST(&tp->t_segq);
735 while (q != NULL &&
736 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
737 *lp++ = htonl(q->tqe_th->th_seq);
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738 *lp++ = htonl(TCP_SACK_BLKEND(
739 q->tqe_th->th_seq + q->tqe_len,
740 q->tqe_th->th_flags));
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741 optlen += TCPOLEN_SACK_BLOCK;
742 q = LIST_NEXT(q, tqe_q);
743 }
744 } else {
745 int n = 0;
746
747 /* Fill in SACK blocks from right side. */
748 while (n < tp->nsackhistory &&
749 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
750 if (tp->sackhistory[n].rblk_start != hstart) {
751 *lp++ = htonl(tp->sackhistory[n].rblk_start);
752 *lp++ = htonl(tp->sackhistory[n].rblk_end);
753 optlen += TCPOLEN_SACK_BLOCK;
754 }
755 ++n;
756 }
757 }
758 tp->reportblk.rblk_start = tp->reportblk.rblk_end;
759 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT);
760 nblocks = (lp - olp - 1) / 2;
761 *olp = htonl(TCPOPT_SACK_ALIGNED |
762 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK));
763 *plen = optlen;
764}