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 * 33 * $DragonFly: src/sys/netinet/tcp_sack.c,v 1.8 2008/08/15 21:37:16 nth Exp $ 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 58 /* 59 * Implemented: 60 * 61 * RFC 2018 62 * RFC 2883 63 * RFC 3517 64 */ 65 66 struct 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 74 static void insert_block(struct scoreboard *scb, struct sackblock *newblock); 75 static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una, 76 u_int maxseg); 77 78 static MALLOC_DEFINE(M_SACKBLOCK, "sblk", "sackblock struct"); 79 80 /* 81 * Per-tcpcb initialization. 82 */ 83 void 84 tcp_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 */ 98 static boolean_t 99 sack_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 */ 149 static __inline struct sackblock * 150 alloc_sackblock(void) 151 { 152 return (kmalloc(sizeof(struct sackblock), M_SACKBLOCK, M_NOWAIT)); 153 } 154 155 /* 156 * Free a SACK block. 157 */ 158 static __inline void 159 free_sackblock(struct sackblock *s) 160 { 161 kfree(s, M_SACKBLOCK); 162 } 163 164 /* 165 * Free up SACK blocks for data that's been acked. 166 */ 167 static void 168 tcp_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); 175 if (scb->lastfound == sb) 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 */ 191 void 192 tcp_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 * Cleanup the reported SACK block information 208 */ 209 void 210 tcp_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 /* 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 */ 221 int 222 tcp_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 */ 243 static void 244 tcp_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 */ 262 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) { 263 tcpstat.tcps_rcvbadsackopt++; 264 break; /* skip all other blocks */ 265 } 266 tcpstat.tcps_sacksbupdate++; 267 268 sb = alloc_sackblock(); 269 if (sb == NULL) { /* do some sort of cleanup? XXX */ 270 tcpstat.tcps_sacksbfailed++; 271 break; /* just skip rest of blocks */ 272 } 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 } 284 285 void 286 tcp_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 */ 300 static void 301 insert_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); 315 tcpstat.tcps_sacksboverflow++; 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); 334 tcpstat.tcps_sacksbreused++; 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); 350 if (scb->lastfound == sb) 351 scb->lastfound = NULL; 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; 364 if (scb->lastfound == sb) 365 scb->lastfound = NULL; 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 375 static void 376 tcp_sack_dump_blocks(struct scoreboard *scb) 377 { 378 struct sackblock *sb; 379 380 kprintf("%d blocks:", scb->nblocks); 381 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 382 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end); 383 kprintf("\n"); 384 } 385 #else 386 static __inline void 387 tcp_sack_dump_blocks(struct scoreboard *scb) 388 { 389 } 390 #endif 391 392 /* 393 * Optimization to quickly determine which packets are lost. 394 */ 395 static void 396 update_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 */ 419 static boolean_t 420 scb_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 */ 428 boolean_t 429 tcp_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 /* 443 * Number of bytes SACKed below seq. 444 */ 445 int 446 tcp_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 /* 460 * Return estimate of the number of bytes outstanding in the network. 461 */ 462 uint32_t 463 tcp_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 */ 489 boolean_t 490 tcp_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)) { 510 sendunsacked: 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; 523 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off; 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 */ 541 void 542 tcp_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 552 void 553 tcp_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 } 560 561 void 562 tcp_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 577 static void 578 tcp_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; 586 587 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory); 588 for (i = 0; i < tp->nsackhistory; ++i) 589 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start, 590 tp->sackhistory[i].rblk_end); 591 kprintf("\n"); 592 } 593 #else 594 static __inline void 595 tcp_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 */ 603 static void 604 tcp_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 */ 632 static void 633 tcp_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 */ 699 void 700 tcp_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)); 711 712 if (tp->t_flags & TF_DUPSEG) 713 tcpstat.tcps_snddsackopt++; 714 else 715 tcpstat.tcps_sndsackopt++; 716 717 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); 748 *lp++ = htonl(TCP_SACK_BLKEND( 749 q->tqe_th->th_seq + q->tqe_len, 750 q->tqe_th->th_flags)); 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 } 775