1 /* $FreeBSD: src/sys/netinet6/frag6.c,v 1.2.2.6 2002/04/28 05:40:26 suz Exp $ */ 2 /* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 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 project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/malloc.h> 36 #include <sys/mbuf.h> 37 #include <sys/domain.h> 38 #include <sys/protosw.h> 39 #include <sys/socket.h> 40 #include <sys/errno.h> 41 #include <sys/time.h> 42 #include <sys/kernel.h> 43 #include <sys/syslog.h> 44 #include <sys/thread2.h> 45 46 #include <net/if.h> 47 #include <net/route.h> 48 #include <net/netisr2.h> 49 #include <net/netmsg2.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_var.h> 53 #include <netinet/ip6.h> 54 #include <netinet6/ip6_var.h> 55 #include <netinet/icmp6.h> 56 57 #include <net/net_osdep.h> 58 59 #define FRAG6_SLOWTIMO (hz / PR_SLOWHZ) 60 61 /* 62 * Define it to get a correct behavior on per-interface statistics. 63 * You will need to perform an extra routing table lookup, per fragment, 64 * to do it. This may, or may not be, a performance hit. 65 */ 66 #define IN6_IFSTAT_STRICT 67 68 static void frag6_enq (struct ip6asfrag *, struct ip6asfrag *); 69 static void frag6_deq (struct ip6asfrag *); 70 static void frag6_insque (struct ip6q *, struct ip6q *); 71 static void frag6_remque (struct ip6q *); 72 static void frag6_freef (struct ip6q *); 73 static void frag6_slowtimo_dispatch (netmsg_t); 74 static void frag6_slowtimo (void *); 75 static void frag6_drain_dispatch (netmsg_t); 76 77 /* XXX we eventually need splreass6, or some real semaphore */ 78 int frag6_doing_reass; 79 u_int frag6_nfragpackets; 80 u_int frag6_nfrags; 81 struct ip6q ip6q; /* ip6 reassemble queue */ 82 83 /* FreeBSD tweak */ 84 MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 85 86 static struct callout frag6_slowtimo_ch; 87 static struct netmsg_base frag6_slowtimo_nmsg; 88 static struct netmsg_base frag6_drain_nmsg; 89 static volatile int frag6_draining; 90 91 /* 92 * Initialise reassembly queue and fragment identifier. 93 */ 94 void 95 frag6_init(void) 96 { 97 struct timeval tv; 98 99 ip6_maxfragpackets = nmbclusters / 4; 100 ip6_maxfrags = nmbclusters / 4; 101 102 /* 103 * in many cases, random() here does NOT return random number 104 * as initialization during bootstrap time occur in fixed order. 105 */ 106 microtime(&tv); 107 ip6_id = krandom() ^ tv.tv_usec; 108 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 109 110 netmsg_init(&frag6_drain_nmsg, NULL, &netisr_adone_rport, 111 MSGF_PRIORITY, frag6_drain_dispatch); 112 113 callout_init_mp(&frag6_slowtimo_ch); 114 netmsg_init(&frag6_slowtimo_nmsg, NULL, &netisr_adone_rport, 115 MSGF_PRIORITY, frag6_slowtimo_dispatch); 116 117 callout_reset_bycpu(&frag6_slowtimo_ch, FRAG6_SLOWTIMO, 118 frag6_slowtimo, NULL, 0); 119 } 120 121 /* 122 * In RFC2460, fragment and reassembly rule do not agree with each other, 123 * in terms of next header field handling in fragment header. 124 * While the sender will use the same value for all of the fragmented packets, 125 * receiver is suggested not to check the consistency. 126 * 127 * fragment rule (p20): 128 * (2) A Fragment header containing: 129 * The Next Header value that identifies the first header of 130 * the Fragmentable Part of the original packet. 131 * -> next header field is same for all fragments 132 * 133 * reassembly rule (p21): 134 * The Next Header field of the last header of the Unfragmentable 135 * Part is obtained from the Next Header field of the first 136 * fragment's Fragment header. 137 * -> should grab it from the first fragment only 138 * 139 * The following note also contradicts with fragment rule - noone is going to 140 * send different fragment with different next header field. 141 * 142 * additional note (p22): 143 * The Next Header values in the Fragment headers of different 144 * fragments of the same original packet may differ. Only the value 145 * from the Offset zero fragment packet is used for reassembly. 146 * -> should grab it from the first fragment only 147 * 148 * There is no explicit reason given in the RFC. Historical reason maybe? 149 */ 150 /* 151 * Fragment input 152 */ 153 int 154 frag6_input(struct mbuf **mp, int *offp, int proto) 155 { 156 struct mbuf *m = *mp, *t; 157 struct ip6_hdr *ip6; 158 struct ip6_frag *ip6f; 159 struct ip6q *q6; 160 struct ip6asfrag *af6, *ip6af, *af6dwn; 161 int offset = *offp, nxt, i, next; 162 int first_frag = 0; 163 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 164 struct ifnet *dstifp; 165 #ifdef IN6_IFSTAT_STRICT 166 static struct route_in6 ro; 167 struct sockaddr_in6 *dst; 168 #endif 169 170 ip6 = mtod(m, struct ip6_hdr *); 171 #ifndef PULLDOWN_TEST 172 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 173 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 174 #else 175 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 176 if (ip6f == NULL) 177 return IPPROTO_DONE; 178 #endif 179 180 dstifp = NULL; 181 #ifdef IN6_IFSTAT_STRICT 182 /* find the destination interface of the packet. */ 183 dst = (struct sockaddr_in6 *)&ro.ro_dst; 184 if (ro.ro_rt && 185 (!(ro.ro_rt->rt_flags & RTF_UP) || 186 !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 187 rtfree(ro.ro_rt); 188 ro.ro_rt = NULL; 189 } 190 if (ro.ro_rt == NULL) { 191 bzero(dst, sizeof(*dst)); 192 dst->sin6_family = AF_INET6; 193 dst->sin6_len = sizeof(struct sockaddr_in6); 194 dst->sin6_addr = ip6->ip6_dst; 195 } 196 rtalloc((struct route *)&ro); 197 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 198 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 199 #else 200 /* we are violating the spec, this is not the destination interface */ 201 if (m->m_flags & M_PKTHDR) 202 dstifp = m->m_pkthdr.rcvif; 203 #endif 204 205 /* jumbo payload can't contain a fragment header */ 206 if (ip6->ip6_plen == 0) { 207 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 208 in6_ifstat_inc(dstifp, ifs6_reass_fail); 209 return IPPROTO_DONE; 210 } 211 212 /* 213 * check whether fragment packet's fragment length is 214 * multiple of 8 octets. 215 * sizeof(struct ip6_frag) == 8 216 * sizeof(struct ip6_hdr) = 40 217 */ 218 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 219 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 220 icmp6_error(m, ICMP6_PARAM_PROB, 221 ICMP6_PARAMPROB_HEADER, 222 offsetof(struct ip6_hdr, ip6_plen)); 223 in6_ifstat_inc(dstifp, ifs6_reass_fail); 224 return IPPROTO_DONE; 225 } 226 227 ip6stat.ip6s_fragments++; 228 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 229 230 /* offset now points to data portion */ 231 offset += sizeof(struct ip6_frag); 232 233 frag6_doing_reass = 1; 234 235 /* 236 * Enforce upper bound on number of fragments. 237 * If maxfrag is 0, never accept fragments. 238 * If maxfrag is -1, accept all fragments without limitation. 239 */ 240 if (ip6_maxfrags < 0) 241 ; 242 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 243 goto dropfrag; 244 245 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 246 if (ip6f->ip6f_ident == q6->ip6q_ident && 247 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 248 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 249 break; 250 251 if (q6 == &ip6q) { 252 /* 253 * the first fragment to arrive, create a reassembly queue. 254 */ 255 first_frag = 1; 256 257 /* 258 * Enforce upper bound on number of fragmented packets 259 * for which we attempt reassembly; 260 * If maxfrag is 0, never accept fragments. 261 * If maxfrag is -1, accept all fragments without limitation. 262 */ 263 if (ip6_maxfragpackets < 0) 264 ; 265 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 266 goto dropfrag; 267 frag6_nfragpackets++; 268 q6 = (struct ip6q *)kmalloc(sizeof(struct ip6q), M_FTABLE, 269 M_NOWAIT | M_ZERO); 270 if (q6 == NULL) 271 goto dropfrag; 272 273 frag6_insque(q6, &ip6q); 274 275 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 276 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 277 #ifdef notyet 278 q6->ip6q_nxtp = (u_char *)nxtp; 279 #endif 280 q6->ip6q_ident = ip6f->ip6f_ident; 281 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 282 q6->ip6q_ttl = IPV6_FRAGTTL; 283 q6->ip6q_src = ip6->ip6_src; 284 q6->ip6q_dst = ip6->ip6_dst; 285 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 286 q6->ip6q_nfrag = 0; 287 } 288 289 /* 290 * If it's the 1st fragment, record the length of the 291 * unfragmentable part and the next header of the fragment header. 292 */ 293 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 294 if (fragoff == 0) { 295 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 296 - sizeof(struct ip6_frag); 297 q6->ip6q_nxt = ip6f->ip6f_nxt; 298 } 299 300 /* 301 * Check that the reassembled packet would not exceed 65535 bytes 302 * in size. 303 * If it would exceed, discard the fragment and return an ICMP error. 304 */ 305 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 306 if (q6->ip6q_unfrglen >= 0) { 307 /* The 1st fragment has already arrived. */ 308 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 309 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 310 offset - sizeof(struct ip6_frag) + 311 offsetof(struct ip6_frag, ip6f_offlg)); 312 frag6_doing_reass = 0; 313 return (IPPROTO_DONE); 314 } 315 } 316 else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 317 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 318 offset - sizeof(struct ip6_frag) + 319 offsetof(struct ip6_frag, ip6f_offlg)); 320 frag6_doing_reass = 0; 321 return (IPPROTO_DONE); 322 } 323 /* 324 * If it's the first fragment, do the above check for each 325 * fragment already stored in the reassembly queue. 326 */ 327 if (fragoff == 0) { 328 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 329 af6 = af6dwn) { 330 af6dwn = af6->ip6af_down; 331 332 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 333 IPV6_MAXPACKET) { 334 struct mbuf *merr = IP6_REASS_MBUF(af6); 335 struct ip6_hdr *ip6err; 336 int erroff = af6->ip6af_offset; 337 338 /* dequeue the fragment. */ 339 frag6_deq(af6); 340 kfree(af6, M_FTABLE); 341 342 /* adjust pointer. */ 343 ip6err = mtod(merr, struct ip6_hdr *); 344 345 /* 346 * Restore source and destination addresses 347 * in the erroneous IPv6 header. 348 */ 349 ip6err->ip6_src = q6->ip6q_src; 350 ip6err->ip6_dst = q6->ip6q_dst; 351 352 icmp6_error(merr, ICMP6_PARAM_PROB, 353 ICMP6_PARAMPROB_HEADER, 354 erroff - sizeof(struct ip6_frag) + 355 offsetof(struct ip6_frag, ip6f_offlg)); 356 } 357 } 358 } 359 360 ip6af = (struct ip6asfrag *)kmalloc(sizeof(struct ip6asfrag), M_FTABLE, 361 M_NOWAIT | M_ZERO); 362 if (ip6af == NULL) 363 goto dropfrag; 364 ip6af->ip6af_head = ip6->ip6_flow; 365 ip6af->ip6af_len = ip6->ip6_plen; 366 ip6af->ip6af_nxt = ip6->ip6_nxt; 367 ip6af->ip6af_hlim = ip6->ip6_hlim; 368 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 369 ip6af->ip6af_off = fragoff; 370 ip6af->ip6af_frglen = frgpartlen; 371 ip6af->ip6af_offset = offset; 372 IP6_REASS_MBUF(ip6af) = m; 373 374 if (first_frag) { 375 af6 = (struct ip6asfrag *)q6; 376 goto insert; 377 } 378 379 /* 380 * Find a segment which begins after this one does. 381 */ 382 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 383 af6 = af6->ip6af_down) 384 if (af6->ip6af_off > ip6af->ip6af_off) 385 break; 386 387 /* 388 * RFC 5722: Drop overlapping fragments 389 */ 390 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 391 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 392 - ip6af->ip6af_off; 393 if (i > 0) { 394 kfree(ip6af, M_FTABLE); 395 goto dropfrag; 396 } 397 } 398 if (af6 != (struct ip6asfrag *)q6) { 399 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 400 if (i > 0) { 401 kfree(ip6af, M_FTABLE); 402 goto dropfrag; 403 } 404 } 405 406 insert: 407 408 /* 409 * Stick new segment in its place; 410 * check for complete reassembly. 411 * Move to front of packet queue, as we are 412 * the most recently active fragmented packet. 413 */ 414 frag6_enq(ip6af, af6->ip6af_up); 415 frag6_nfrags++; 416 q6->ip6q_nfrag++; 417 #if 0 /* xxx */ 418 if (q6 != ip6q.ip6q_next) { 419 frag6_remque(q6); 420 frag6_insque(q6, &ip6q); 421 } 422 #endif 423 next = 0; 424 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 425 af6 = af6->ip6af_down) { 426 if (af6->ip6af_off != next) { 427 frag6_doing_reass = 0; 428 return IPPROTO_DONE; 429 } 430 next += af6->ip6af_frglen; 431 } 432 if (af6->ip6af_up->ip6af_mff) { 433 frag6_doing_reass = 0; 434 return IPPROTO_DONE; 435 } 436 437 /* 438 * Reassembly is complete; concatenate fragments. 439 */ 440 ip6af = q6->ip6q_down; 441 t = m = IP6_REASS_MBUF(ip6af); 442 af6 = ip6af->ip6af_down; 443 frag6_deq(ip6af); 444 while (af6 != (struct ip6asfrag *)q6) { 445 af6dwn = af6->ip6af_down; 446 frag6_deq(af6); 447 while (t->m_next) 448 t = t->m_next; 449 t->m_next = IP6_REASS_MBUF(af6); 450 m_adj(t->m_next, af6->ip6af_offset); 451 kfree(af6, M_FTABLE); 452 af6 = af6dwn; 453 } 454 455 /* adjust offset to point where the original next header starts */ 456 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 457 kfree(ip6af, M_FTABLE); 458 459 /* 460 * Make sure completed packet does not overflow the max packet length. 461 */ 462 if ((u_int)next + (u_int)offset - sizeof(struct ip6_hdr) > 463 IPV6_MAXPACKET) 464 { 465 frag6_freef(q6); 466 goto dropfrag; 467 } 468 469 ip6 = mtod(m, struct ip6_hdr *); 470 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 471 ip6->ip6_src = q6->ip6q_src; 472 ip6->ip6_dst = q6->ip6q_dst; 473 nxt = q6->ip6q_nxt; 474 #ifdef notyet 475 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 476 #endif 477 478 /* 479 * Delete frag6 header with as a few cost as possible. 480 */ 481 if (offset < m->m_len) { 482 bcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 483 offset); 484 m->m_data += sizeof(struct ip6_frag); 485 m->m_len -= sizeof(struct ip6_frag); 486 } else { 487 /* this comes with no copy if the boundary is on cluster */ 488 if ((t = m_split(m, offset, M_NOWAIT)) == NULL) { 489 frag6_remque(q6); 490 frag6_nfrags -= q6->ip6q_nfrag; 491 kfree(q6, M_FTABLE); 492 frag6_nfragpackets--; 493 goto dropfrag; 494 } 495 m_adj(t, sizeof(struct ip6_frag)); 496 m_cat(m, t); 497 } 498 499 /* 500 * Store NXT to the original. 501 */ 502 { 503 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 504 *prvnxtp = nxt; 505 } 506 507 frag6_remque(q6); 508 frag6_nfrags -= q6->ip6q_nfrag; 509 kfree(q6, M_FTABLE); 510 frag6_nfragpackets--; 511 512 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 513 int plen = 0; 514 for (t = m; t; t = t->m_next) 515 plen += t->m_len; 516 m->m_pkthdr.len = plen; 517 } 518 519 ip6stat.ip6s_reassembled++; 520 in6_ifstat_inc(dstifp, ifs6_reass_ok); 521 522 /* 523 * Reassembly complete, return the next protocol. 524 * Be sure to clear M_HASH to force the packet 525 * to be re-characterized. 526 */ 527 m->m_flags &= ~M_HASH; 528 529 *mp = m; 530 *offp = offset; 531 532 frag6_doing_reass = 0; 533 return nxt; 534 535 dropfrag: 536 in6_ifstat_inc(dstifp, ifs6_reass_fail); 537 ip6stat.ip6s_fragdropped++; 538 m_freem(m); 539 frag6_doing_reass = 0; 540 return IPPROTO_DONE; 541 } 542 543 /* 544 * Free a fragment reassembly header and all 545 * associated datagrams. 546 */ 547 static void 548 frag6_freef(struct ip6q *q6) 549 { 550 struct ip6asfrag *af6, *down6; 551 552 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 553 af6 = down6) { 554 struct mbuf *m = IP6_REASS_MBUF(af6); 555 556 down6 = af6->ip6af_down; 557 frag6_deq(af6); 558 559 /* 560 * Return ICMP time exceeded error for the 1st fragment. 561 * Just free other fragments. 562 */ 563 if (af6->ip6af_off == 0) { 564 struct ip6_hdr *ip6; 565 566 /* adjust pointer */ 567 ip6 = mtod(m, struct ip6_hdr *); 568 569 /* restoure source and destination addresses */ 570 ip6->ip6_src = q6->ip6q_src; 571 ip6->ip6_dst = q6->ip6q_dst; 572 573 icmp6_error(m, ICMP6_TIME_EXCEEDED, 574 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 575 } else 576 m_freem(m); 577 kfree(af6, M_FTABLE); 578 } 579 frag6_remque(q6); 580 frag6_nfrags -= q6->ip6q_nfrag; 581 kfree(q6, M_FTABLE); 582 frag6_nfragpackets--; 583 } 584 585 /* 586 * Put an ip fragment on a reassembly chain. 587 * Like insque, but pointers in middle of structure. 588 */ 589 static void 590 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 591 { 592 af6->ip6af_up = up6; 593 af6->ip6af_down = up6->ip6af_down; 594 up6->ip6af_down->ip6af_up = af6; 595 up6->ip6af_down = af6; 596 } 597 598 /* 599 * To frag6_enq as remque is to insque. 600 */ 601 static void 602 frag6_deq(struct ip6asfrag *af6) 603 { 604 af6->ip6af_up->ip6af_down = af6->ip6af_down; 605 af6->ip6af_down->ip6af_up = af6->ip6af_up; 606 } 607 608 static void 609 frag6_insque(struct ip6q *new, struct ip6q *old) 610 { 611 new->ip6q_prev = old; 612 new->ip6q_next = old->ip6q_next; 613 old->ip6q_next->ip6q_prev= new; 614 old->ip6q_next = new; 615 } 616 617 static void 618 frag6_remque(struct ip6q *p6) 619 { 620 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 621 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 622 } 623 624 /* 625 * IPv6 reassembling timer processing; 626 * if a timer expires on a reassembly 627 * queue, discard it. 628 */ 629 static void 630 frag6_slowtimo_dispatch(netmsg_t nmsg) 631 { 632 struct ip6q *q6; 633 634 ASSERT_NETISR0; 635 636 /* Reply ASAP. */ 637 crit_enter(); 638 netisr_replymsg(&nmsg->base, 0); 639 crit_exit(); 640 641 frag6_doing_reass = 1; 642 q6 = ip6q.ip6q_next; 643 if (q6) 644 while (q6 != &ip6q) { 645 --q6->ip6q_ttl; 646 q6 = q6->ip6q_next; 647 if (q6->ip6q_prev->ip6q_ttl == 0) { 648 ip6stat.ip6s_fragtimeout++; 649 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 650 frag6_freef(q6->ip6q_prev); 651 } 652 } 653 /* 654 * If we are over the maximum number of fragments 655 * (due to the limit being lowered), drain off 656 * enough to get down to the new limit. 657 */ 658 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 659 ip6q.ip6q_prev) { 660 ip6stat.ip6s_fragoverflow++; 661 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 662 frag6_freef(ip6q.ip6q_prev); 663 } 664 frag6_doing_reass = 0; 665 666 #if 0 667 /* 668 * Routing changes might produce a better route than we last used; 669 * make sure we notice eventually, even if forwarding only for one 670 * destination and the cache is never replaced. 671 */ 672 if (ip6_forward_rt.ro_rt) { 673 RTFREE(ip6_forward_rt.ro_rt); 674 ip6_forward_rt.ro_rt = NULL; 675 } 676 if (ipsrcchk_rt.ro_rt) { 677 RTFREE(ipsrcchk_rt.ro_rt); 678 ipsrcchk_rt.ro_rt = NULL; 679 } 680 #endif 681 callout_reset(&frag6_slowtimo_ch, FRAG6_SLOWTIMO, frag6_slowtimo, NULL); 682 } 683 684 static void 685 frag6_slowtimo(void *dummy __unused) 686 { 687 struct netmsg_base *nmsg = &frag6_slowtimo_nmsg; 688 689 KKASSERT(mycpuid == 0); 690 691 crit_enter(); 692 if (nmsg->lmsg.ms_flags & MSGF_DONE) 693 netisr_sendmsg_oncpu(nmsg); 694 crit_exit(); 695 } 696 697 /* 698 * Drain off all datagram fragments. 699 */ 700 static void 701 frag6_drain_oncpu(void) 702 { 703 704 ASSERT_NETISR0; 705 706 if (frag6_doing_reass) 707 return; 708 while (ip6q.ip6q_next != &ip6q) { 709 ip6stat.ip6s_fragdropped++; 710 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 711 frag6_freef(ip6q.ip6q_next); 712 } 713 } 714 715 static void 716 frag6_drain_dispatch(netmsg_t nmsg) 717 { 718 719 ASSERT_NETISR0; 720 721 crit_enter(); 722 netisr_replymsg(&nmsg->base, 0); 723 crit_exit(); 724 725 frag6_drain_oncpu(); 726 frag6_draining = 0; 727 } 728 729 static void 730 frag6_drain_ipi(void *dummy __unused) 731 { 732 struct netmsg_base *nmsg = &frag6_drain_nmsg; 733 734 KKASSERT(mycpuid == 0); 735 736 crit_enter(); 737 if (nmsg->lmsg.ms_flags & MSGF_DONE) 738 netisr_sendmsg_oncpu(nmsg); 739 crit_exit(); 740 } 741 742 void 743 frag6_drain(void) 744 { 745 746 if (IN_NETISR(0)) { 747 frag6_drain_oncpu(); 748 return; 749 } 750 751 if (!frag6_nfrags || frag6_draining) { 752 /* No fragments or is draining; done. */ 753 return; 754 } 755 frag6_draining = 1; 756 757 /* Target cpu0. */ 758 lwkt_send_ipiq_bycpu(0, frag6_drain_ipi, NULL); 759 } 760