tcp/sack: Cleanup the SACK related bits when return from tcp_input slow path
[dragonfly.git] / sys / netinet / tcp_sack.c
CommitLineData
91489f6b
JH
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
91489f6b
JH
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");
91489f6b
JH
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));
91489f6b
JH
153}
154
155/*
156 * Free a SACK block.
157 */
158static __inline void
159free_sackblock(struct sackblock *s)
160{
12f68b86 161 kfree(s, M_SACKBLOCK);
91489f6b
JH
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)
91489f6b
JH
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/*
d58ca578
SZ
207 * Cleanup the reported SACK block information
208 */
209void
210tcp_sack_report_cleanup(struct tcpcb *tp)
211{
212 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT);
213 tp->reportblk.rblk_start = tp->reportblk.rblk_end;
214}
215
216/*
91489f6b
JH
217 * Returns 0 if not D-SACK block,
218 * 1 if D-SACK,
219 * 2 if duplicate of out-of-order D-SACK block.
220 */
221int
222tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks,
223 tcp_seq snd_una)
224{
225 if (numblocks == 0)
226 return 0;
227
228 if (SEQ_LT(blocks[0].rblk_start, snd_una))
229 return 1;
230
231 /* block 0 inside block 1 */
232 if (numblocks > 1 &&
233 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) &&
234 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end))
235 return 2;
236
237 return 0;
238}
239
240/*
241 * Update scoreboard on new incoming ACK.
242 */
243static void
244tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to)
245{
246 const int numblocks = to->to_nsackblocks;
247 struct raw_sackblock *blocks = to->to_sackblocks;
248 struct scoreboard *scb = &tp->scb;
249 struct sackblock *sb;
250 int startblock;
251 int i;
252
253 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0)
254 startblock = 1;
255 else
256 startblock = 0;
257
258 for (i = startblock; i < numblocks; i++) {
259 struct raw_sackblock *newsackblock = &blocks[i];
260
261 /* don't accept bad SACK blocks */
02cc2f35
SZ
262 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) {
263 tcpstat.tcps_rcvbadsackopt++;
91489f6b 264 break; /* skip all other blocks */
02cc2f35
SZ
265 }
266 tcpstat.tcps_sacksbupdate++;
91489f6b
JH
267
268 sb = alloc_sackblock();
02cc2f35
SZ
269 if (sb == NULL) { /* do some sort of cleanup? XXX */
270 tcpstat.tcps_sacksbfailed++;
91489f6b 271 break; /* just skip rest of blocks */
02cc2f35 272 }
91489f6b
JH
273 sb->sblk_start = newsackblock->rblk_start;
274 sb->sblk_end = newsackblock->rblk_end;
275 if (TAILQ_EMPTY(&scb->sackblocks)) {
276 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks"));
277 scb->nblocks = 1;
278 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list);
279 } else {
280 insert_block(scb, sb);
281 }
282 }
283}
284
285void
286tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to)
287{
288 struct scoreboard *scb = &tp->scb;
289
290 tcp_sack_ack_blocks(scb, tp->snd_una);
291 tcp_sack_add_blocks(tp, to);
292 update_lostseq(scb, tp->snd_una, tp->t_maxseg);
293 if (SEQ_LT(tp->rexmt_high, tp->snd_una))
294 tp->rexmt_high = tp->snd_una;
295}
296
297/*
298 * Insert SACK block into sender's scoreboard.
299 */
300static void
301insert_block(struct scoreboard *scb, struct sackblock *newblock)
302{
303 struct sackblock *sb, *workingblock;
304 boolean_t overlap_front;
305
306 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks"));
307
308 if (scb->nblocks == MAXSAVEDBLOCKS) {
309 /*
310 * Should try to kick out older blocks XXX JH
311 * May be able to coalesce with existing block.
312 * Or, go other way and free all blocks if we hit this limit.
313 */
314 free_sackblock(newblock);
02cc2f35 315 tcpstat.tcps_sacksboverflow++;
91489f6b
JH
316 return;
317 }
318 KASSERT(scb->nblocks < MAXSAVEDBLOCKS,
319 ("too many SACK blocks %d", scb->nblocks));
320
321 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb);
322
323 if (sb == NULL) {
324 workingblock = newblock;
325 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list);
326 ++scb->nblocks;
327 } else {
328 if (overlap_front || sb->sblk_end == newblock->sblk_start) {
329 /* extend old block and discard new one */
330 workingblock = sb;
331 if (SEQ_GT(newblock->sblk_end, sb->sblk_end))
332 sb->sblk_end = newblock->sblk_end;
333 free_sackblock(newblock);
02cc2f35 334 tcpstat.tcps_sacksbreused++;
91489f6b
JH
335 } else {
336 workingblock = newblock;
337 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock,
338 sblk_list);
339 ++scb->nblocks;
340 }
341 }
342
343 /* Consolidate right-hand side. */
344 sb = TAILQ_NEXT(workingblock, sblk_list);
345 while (sb != NULL &&
346 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) {
347 struct sackblock *nextblock;
348
349 nextblock = TAILQ_NEXT(sb, sblk_list);
9e3d6c96
MD
350 if (scb->lastfound == sb)
351 scb->lastfound = NULL;
91489f6b
JH
352 /* Remove completely overlapped block */
353 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
354 free_sackblock(sb);
355 --scb->nblocks;
356 KASSERT(scb->nblocks > 0,
357 ("removed overlapped block: %d blocks left", scb->nblocks));
358 sb = nextblock;
359 }
360 if (sb != NULL &&
361 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) {
362 /* Extend new block to cover partially overlapped old block. */
363 workingblock->sblk_end = sb->sblk_end;
9e3d6c96
MD
364 if (scb->lastfound == sb)
365 scb->lastfound = NULL;
91489f6b
JH
366 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list);
367 free_sackblock(sb);
368 --scb->nblocks;
369 KASSERT(scb->nblocks > 0,
370 ("removed partial right: %d blocks left", scb->nblocks));
371 }
372}
373
374#ifdef DEBUG_SACK_BLOCKS
375static void
376tcp_sack_dump_blocks(struct scoreboard *scb)
377{
378 struct sackblock *sb;
379
a6ec04bc 380 kprintf("%d blocks:", scb->nblocks);
91489f6b 381 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
a6ec04bc
SW
382 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end);
383 kprintf("\n");
91489f6b
JH
384}
385#else
386static __inline void
387tcp_sack_dump_blocks(struct scoreboard *scb)
388{
389}
390#endif
391
392/*
393 * Optimization to quickly determine which packets are lost.
394 */
395static void
396update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg)
397{
398 struct sackblock *sb;
399 int nsackblocks = 0;
400 int bytes_sacked = 0;
401
402 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list);
403 while (sb != NULL) {
404 ++nsackblocks;
405 bytes_sacked += sb->sblk_end - sb->sblk_start;
406 if (nsackblocks == tcprexmtthresh ||
407 bytes_sacked >= tcprexmtthresh * maxseg) {
408 scb->lostseq = sb->sblk_start;
409 return;
410 }
411 sb = TAILQ_PREV(sb, sackblock_list, sblk_list);
412 }
413 scb->lostseq = snd_una;
414}
415
416/*
417 * Return whether the given sequence number is considered lost.
418 */
419static boolean_t
420scb_islost(struct scoreboard *scb, tcp_seq seqnum)
421{
422 return SEQ_LT(seqnum, scb->lostseq);
423}
424
425/*
426 * True if at least "amount" has been SACKed. Used by Early Retransmit.
427 */
428boolean_t
429tcp_sack_has_sacked(struct scoreboard *scb, u_int amount)
430{
431 struct sackblock *sb;
432 int bytes_sacked = 0;
433
434 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
435 bytes_sacked += sb->sblk_end - sb->sblk_start;
436 if (bytes_sacked >= amount)
437 return TRUE;
438 }
439 return FALSE;
440}
441
442/*
9a5b142f
JH
443 * Number of bytes SACKed below seq.
444 */
445int
446tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq)
447{
448 struct sackblock *sb;
449 int bytes_sacked = 0;
450
451 sb = TAILQ_FIRST(&scb->sackblocks);
452 while (sb && SEQ_GT(seq, sb->sblk_start)) {
453 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start;
454 sb = TAILQ_NEXT(sb, sblk_list);
455 }
456 return bytes_sacked;
457}
458
459/*
91489f6b
JH
460 * Return estimate of the number of bytes outstanding in the network.
461 */
462uint32_t
463tcp_sack_compute_pipe(struct tcpcb *tp)
464{
465 struct scoreboard *scb = &tp->scb;
466 struct sackblock *sb;
467 int nlost, nretransmitted;
468 tcp_seq end;
469
470 nlost = tp->snd_max - scb->lostseq;
471 nretransmitted = tp->rexmt_high - tp->snd_una;
472
473 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) {
474 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) {
475 end = seq_min(sb->sblk_end, tp->rexmt_high);
476 nretransmitted -= end - sb->sblk_start;
477 }
478 if (SEQ_GEQ(sb->sblk_start, scb->lostseq))
479 nlost -= sb->sblk_end - sb->sblk_start;
480 }
481
482 return (nlost + nretransmitted);
483}
484
485/*
486 * Return the sequence number and length of the next segment to transmit
487 * when in Fast Recovery.
488 */
489boolean_t
490tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen,
491 boolean_t *lostdup)
492{
493 struct scoreboard *scb = &tp->scb;
494 struct socket *so = tp->t_inpcb->inp_socket;
495 struct sackblock *sb;
496 const struct sackblock *lastblock =
497 TAILQ_LAST(&scb->sackblocks, sackblock_list);
498 tcp_seq torexmt;
499 long len, off;
500
501 /* skip SACKed data */
502 tcp_sack_skip_sacked(scb, &tp->rexmt_high);
503
504 /* Look for lost data. */
505 torexmt = tp->rexmt_high;
506 *lostdup = FALSE;
507 if (lastblock != NULL) {
508 if (SEQ_LT(torexmt, lastblock->sblk_end) &&
509 scb_islost(scb, torexmt)) {
510sendunsacked:
511 *nextrexmt = torexmt;
512 /* If the left-hand edge has been SACKed, pull it in. */
513 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb))
514 *plen = sb->sblk_start - torexmt;
515 else
516 *plen = tp->t_maxseg;
517 return TRUE;
518 }
519 }
520
521 /* See if unsent data available within send window. */
522 off = tp->snd_max - tp->snd_una;
6d49aa6f 523 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off;
91489f6b
JH
524 if (len > 0) {
525 *nextrexmt = tp->snd_max; /* Send new data. */
526 *plen = tp->t_maxseg;
527 return TRUE;
528 }
529
530 /* We're less certain this data has been lost. */
531 if (lastblock == NULL || SEQ_LT(torexmt, lastblock->sblk_end))
532 goto sendunsacked;
533
534 return FALSE;
535}
536
537/*
538 * Return the next sequence number higher than "*prexmt" that has
539 * not been SACKed.
540 */
541void
542tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt)
543{
544 struct sackblock *sb;
545
546 /* skip SACKed data */
547 if (sack_block_lookup(scb, *prexmt, &sb))
548 *prexmt = sb->sblk_end;
549}
550
551#ifdef later
552void
553tcp_sack_save_scoreboard(struct scoreboard *scb)
554{
555 struct scoreboard *scb = &tp->scb;
556
557 scb->sackblocks_prev = scb->sackblocks;
558 TAILQ_INIT(&scb->sackblocks);
559}
560
561void
562tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una,
563 u_int maxseg)
564{
565 struct sackblock *sb;
566
567 scb->sackblocks = scb->sackblocks_prev;
568 scb->nblocks = 0;
569 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list)
570 ++scb->nblocks;
571 tcp_sack_ack_blocks(scb, snd_una);
572 scb->lastfound = NULL;
573}
574#endif
575
576#ifdef DEBUG_SACK_HISTORY
577static void
578tcp_sack_dump_history(char *msg, struct tcpcb *tp)
579{
580 int i;
581 static int ndumped;
582
583 /* only need a couple of these to debug most problems */
584 if (++ndumped > 900)
585 return;
586
a6ec04bc 587 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory);
91489f6b 588 for (i = 0; i < tp->nsackhistory; ++i)
a6ec04bc 589 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start,
91489f6b 590 tp->sackhistory[i].rblk_end);
a6ec04bc 591 kprintf("\n");
91489f6b
JH
592}
593#else
594static __inline void
595tcp_sack_dump_history(char *msg, struct tcpcb *tp)
596{
597}
598#endif
599
600/*
601 * Remove old SACK blocks from the SACK history that have already been ACKed.
602 */
603static void
604tcp_sack_ack_history(struct tcpcb *tp)
605{
606 int i, nblocks, openslot;
607
608 tcp_sack_dump_history("before tcp_sack_ack_history", tp);
609 nblocks = tp->nsackhistory;
610 for (i = openslot = 0; i < nblocks; ++i) {
611 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) {
612 --tp->nsackhistory;
613 continue;
614 }
615 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt))
616 tp->sackhistory[i].rblk_start = tp->rcv_nxt;
617 if (i == openslot)
618 ++openslot;
619 else
620 tp->sackhistory[openslot++] = tp->sackhistory[i];
621 }
622 tcp_sack_dump_history("after tcp_sack_ack_history", tp);
623 KASSERT(openslot == tp->nsackhistory,
624 ("tcp_sack_ack_history miscounted: %d != %d",
625 openslot, tp->nsackhistory));
626}
627
628/*
629 * Add or merge newblock into reported history.
630 * Also remove or update SACK blocks that will be acked.
631 */
632static void
633tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end)
634{
635 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS];
636 int i, cindex;
637
638 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp);
639 /*
640 * Six cases:
641 * 0) no overlap
642 * 1) newblock == oldblock
643 * 2) oldblock contains newblock
644 * 3) newblock contains oldblock
645 * 4) tail of oldblock overlaps or abuts start of newblock
646 * 5) tail of newblock overlaps or abuts head of oldblock
647 */
648 for (i = cindex = 0; i < tp->nsackhistory; ++i) {
649 struct raw_sackblock *oldblock = &tp->sackhistory[i];
650 tcp_seq old_start = oldblock->rblk_start;
651 tcp_seq old_end = oldblock->rblk_end;
652
653 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) {
654 /* Case 0: no overlap. Copy old block. */
655 copy[cindex++] = *oldblock;
656 continue;
657 }
658
659 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) {
660 /* Cases 1 & 2. Move block to front of history. */
661 int j;
662
663 start = old_start;
664 end = old_end;
665 /* no need to check rest of blocks */
666 for (j = i + 1; j < tp->nsackhistory; ++j)
667 copy[cindex++] = tp->sackhistory[j];
668 break;
669 }
670
671 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) {
672 /* Case 4: extend start of new block. */
673 start = old_start;
674 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) {
675 /* Case 5: extend end of new block */
676 end = old_end;
677 } else {
678 /* Case 3. Delete old block by not copying it. */
679 KASSERT(SEQ_LEQ(start, old_start) &&
680 SEQ_GEQ(end, old_end),
681 ("bad logic: old [%u, %u), new [%u, %u)",
682 old_start, old_end, start, end));
683 }
684 }
685
686 /* insert new block */
687 tp->sackhistory[0].rblk_start = start;
688 tp->sackhistory[0].rblk_end = end;
689 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1);
690 for (i = 0; i < cindex; ++i)
691 tp->sackhistory[i + 1] = copy[i];
692 tp->nsackhistory = cindex + 1;
693 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp);
694}
695
696/*
697 * Fill in SACK report to return to data sender.
698 */
699void
700tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen)
701{
702 u_int optlen = *plen;
703 uint32_t *lp = (uint32_t *)(opt + optlen);
704 uint32_t *olp;
705 tcp_seq hstart = tp->rcv_nxt, hend;
706 int nblocks;
707
708 KASSERT(TCP_MAXOLEN - optlen >=
709 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK,
710 ("no room for SACK header and one block: optlen %d", optlen));
711
02cc2f35
SZ
712 if (tp->t_flags & TF_DUPSEG)
713 tcpstat.tcps_snddsackopt++;
714 else
715 tcpstat.tcps_sndsackopt++;
716
91489f6b
JH
717 olp = lp++;
718 optlen += TCPOLEN_SACK_ALIGNED;
719
720 tcp_sack_ack_history(tp);
721 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) {
722 *lp++ = htonl(tp->reportblk.rblk_start);
723 *lp++ = htonl(tp->reportblk.rblk_end);
724 optlen += TCPOLEN_SACK_BLOCK;
725 hstart = tp->reportblk.rblk_start;
726 hend = tp->reportblk.rblk_end;
727 if (tp->t_flags & TF_ENCLOSESEG) {
728 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK,
729 ("no room for enclosing SACK block: oplen %d",
730 optlen));
731 *lp++ = htonl(tp->encloseblk.rblk_start);
732 *lp++ = htonl(tp->encloseblk.rblk_end);
733 optlen += TCPOLEN_SACK_BLOCK;
734 hstart = tp->encloseblk.rblk_start;
735 hend = tp->encloseblk.rblk_end;
736 }
737 if (SEQ_GT(hstart, tp->rcv_nxt))
738 tcp_sack_update_reported_history(tp, hstart, hend);
739 }
740 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) {
741 /* Fill in from left! Walk re-assembly queue. */
742 struct tseg_qent *q;
743
744 q = LIST_FIRST(&tp->t_segq);
745 while (q != NULL &&
746 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
747 *lp++ = htonl(q->tqe_th->th_seq);
3a5d999b
SZ
748 *lp++ = htonl(TCP_SACK_BLKEND(
749 q->tqe_th->th_seq + q->tqe_len,
750 q->tqe_th->th_flags));
91489f6b
JH
751 optlen += TCPOLEN_SACK_BLOCK;
752 q = LIST_NEXT(q, tqe_q);
753 }
754 } else {
755 int n = 0;
756
757 /* Fill in SACK blocks from right side. */
758 while (n < tp->nsackhistory &&
759 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) {
760 if (tp->sackhistory[n].rblk_start != hstart) {
761 *lp++ = htonl(tp->sackhistory[n].rblk_start);
762 *lp++ = htonl(tp->sackhistory[n].rblk_end);
763 optlen += TCPOLEN_SACK_BLOCK;
764 }
765 ++n;
766 }
767 }
768 tp->reportblk.rblk_start = tp->reportblk.rblk_end;
769 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT);
770 nblocks = (lp - olp - 1) / 2;
771 *olp = htonl(TCPOPT_SACK_ALIGNED |
772 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK));
773 *plen = optlen;
774}