| 1 | /* $NetBSD: frag6.c,v 1.57 2016/11/09 03:49:38 ozaki-r Exp $ */ |
| 2 | /* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun 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/cdefs.h> |
| 34 | __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.57 2016/11/09 03:49:38 ozaki-r Exp $" ); |
| 35 | |
| 36 | #include <sys/param.h> |
| 37 | #include <sys/systm.h> |
| 38 | #include <sys/mbuf.h> |
| 39 | #include <sys/domain.h> |
| 40 | #include <sys/protosw.h> |
| 41 | #include <sys/socket.h> |
| 42 | #include <sys/socketvar.h> |
| 43 | #include <sys/errno.h> |
| 44 | #include <sys/time.h> |
| 45 | #include <sys/kmem.h> |
| 46 | #include <sys/kernel.h> |
| 47 | #include <sys/syslog.h> |
| 48 | |
| 49 | #include <net/if.h> |
| 50 | #include <net/route.h> |
| 51 | |
| 52 | #include <netinet/in.h> |
| 53 | #include <netinet/in_var.h> |
| 54 | #include <netinet/ip6.h> |
| 55 | #include <netinet6/ip6_var.h> |
| 56 | #include <netinet6/ip6_private.h> |
| 57 | #include <netinet/icmp6.h> |
| 58 | |
| 59 | #include <net/net_osdep.h> |
| 60 | |
| 61 | static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); |
| 62 | static void frag6_deq(struct ip6asfrag *); |
| 63 | static void frag6_insque(struct ip6q *, struct ip6q *); |
| 64 | static void frag6_remque(struct ip6q *); |
| 65 | static void frag6_freef(struct ip6q *); |
| 66 | |
| 67 | static int frag6_drainwanted; |
| 68 | |
| 69 | u_int frag6_nfragpackets; |
| 70 | u_int frag6_nfrags; |
| 71 | struct ip6q ip6q; /* ip6 reassemble queue */ |
| 72 | |
| 73 | static kmutex_t frag6_lock; |
| 74 | |
| 75 | /* |
| 76 | * Initialise reassembly queue and fragment identifier. |
| 77 | */ |
| 78 | void |
| 79 | frag6_init(void) |
| 80 | { |
| 81 | |
| 82 | ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; |
| 83 | mutex_init(&frag6_lock, MUTEX_DEFAULT, IPL_NET); |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * IPv6 fragment input. |
| 88 | * |
| 89 | * In RFC2460, fragment and reassembly rule do not agree with each other, |
| 90 | * in terms of next header field handling in fragment header. |
| 91 | * While the sender will use the same value for all of the fragmented packets, |
| 92 | * receiver is suggested not to check the consistency. |
| 93 | * |
| 94 | * fragment rule (p20): |
| 95 | * (2) A Fragment header containing: |
| 96 | * The Next Header value that identifies the first header of |
| 97 | * the Fragmentable Part of the original packet. |
| 98 | * -> next header field is same for all fragments |
| 99 | * |
| 100 | * reassembly rule (p21): |
| 101 | * The Next Header field of the last header of the Unfragmentable |
| 102 | * Part is obtained from the Next Header field of the first |
| 103 | * fragment's Fragment header. |
| 104 | * -> should grab it from the first fragment only |
| 105 | * |
| 106 | * The following note also contradicts with fragment rule - noone is going to |
| 107 | * send different fragment with different next header field. |
| 108 | * |
| 109 | * additional note (p22): |
| 110 | * The Next Header values in the Fragment headers of different |
| 111 | * fragments of the same original packet may differ. Only the value |
| 112 | * from the Offset zero fragment packet is used for reassembly. |
| 113 | * -> should grab it from the first fragment only |
| 114 | * |
| 115 | * There is no explicit reason given in the RFC. Historical reason maybe? |
| 116 | */ |
| 117 | int |
| 118 | frag6_input(struct mbuf **mp, int *offp, int proto) |
| 119 | { |
| 120 | struct rtentry *rt; |
| 121 | struct mbuf *m = *mp, *t; |
| 122 | struct ip6_hdr *ip6; |
| 123 | struct ip6_frag *ip6f; |
| 124 | struct ip6q *q6; |
| 125 | struct ip6asfrag *af6, *ip6af, *af6dwn; |
| 126 | int offset = *offp, nxt, i, next; |
| 127 | int first_frag = 0; |
| 128 | int fragoff, frgpartlen; /* must be larger than u_int16_t */ |
| 129 | struct ifnet *dstifp; |
| 130 | static struct route ro; |
| 131 | union { |
| 132 | struct sockaddr dst; |
| 133 | struct sockaddr_in6 dst6; |
| 134 | } u; |
| 135 | |
| 136 | ip6 = mtod(m, struct ip6_hdr *); |
| 137 | IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); |
| 138 | if (ip6f == NULL) |
| 139 | return IPPROTO_DONE; |
| 140 | |
| 141 | dstifp = NULL; |
| 142 | /* find the destination interface of the packet. */ |
| 143 | sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0); |
| 144 | if ((rt = rtcache_lookup(&ro, &u.dst)) != NULL && rt->rt_ifa != NULL) |
| 145 | dstifp = ((struct in6_ifaddr *)rt->rt_ifa)->ia_ifp; |
| 146 | |
| 147 | /* jumbo payload can't contain a fragment header */ |
| 148 | if (ip6->ip6_plen == 0) { |
| 149 | icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); |
| 150 | in6_ifstat_inc(dstifp, ifs6_reass_fail); |
| 151 | goto done; |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * check whether fragment packet's fragment length is |
| 156 | * multiple of 8 octets. |
| 157 | * sizeof(struct ip6_frag) == 8 |
| 158 | * sizeof(struct ip6_hdr) = 40 |
| 159 | */ |
| 160 | if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && |
| 161 | (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { |
| 162 | icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, |
| 163 | offsetof(struct ip6_hdr, ip6_plen)); |
| 164 | in6_ifstat_inc(dstifp, ifs6_reass_fail); |
| 165 | goto done; |
| 166 | } |
| 167 | |
| 168 | IP6_STATINC(IP6_STAT_FRAGMENTS); |
| 169 | in6_ifstat_inc(dstifp, ifs6_reass_reqd); |
| 170 | |
| 171 | /* offset now points to data portion */ |
| 172 | offset += sizeof(struct ip6_frag); |
| 173 | |
| 174 | /* |
| 175 | * RFC6946: A host that receives an IPv6 packet which includes |
| 176 | * a Fragment Header with the "Fragmen Offset" equal to 0 and |
| 177 | * the "M" bit equal to 0 MUST process such packet in isolation |
| 178 | * from any other packets/fragments. |
| 179 | */ |
| 180 | fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); |
| 181 | if (fragoff == 0 && !(ip6f->ip6f_offlg & IP6F_MORE_FRAG)) { |
| 182 | IP6_STATINC(IP6_STAT_REASSEMBLED); |
| 183 | in6_ifstat_inc(dstifp, ifs6_reass_ok); |
| 184 | *offp = offset; |
| 185 | return ip6f->ip6f_nxt; |
| 186 | } |
| 187 | |
| 188 | mutex_enter(&frag6_lock); |
| 189 | |
| 190 | /* |
| 191 | * Enforce upper bound on number of fragments. |
| 192 | * If maxfrag is 0, never accept fragments. |
| 193 | * If maxfrag is -1, accept all fragments without limitation. |
| 194 | */ |
| 195 | if (ip6_maxfrags < 0) |
| 196 | ; |
| 197 | else if (frag6_nfrags >= (u_int)ip6_maxfrags) |
| 198 | goto dropfrag; |
| 199 | |
| 200 | for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) |
| 201 | if (ip6f->ip6f_ident == q6->ip6q_ident && |
| 202 | IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && |
| 203 | IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) |
| 204 | break; |
| 205 | |
| 206 | if (q6 == &ip6q) { |
| 207 | /* |
| 208 | * the first fragment to arrive, create a reassembly queue. |
| 209 | */ |
| 210 | first_frag = 1; |
| 211 | |
| 212 | /* |
| 213 | * Enforce upper bound on number of fragmented packets |
| 214 | * for which we attempt reassembly; |
| 215 | * If maxfragpackets is 0, never accept fragments. |
| 216 | * If maxfragpackets is -1, accept all fragments without |
| 217 | * limitation. |
| 218 | */ |
| 219 | if (ip6_maxfragpackets < 0) |
| 220 | ; |
| 221 | else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) |
| 222 | goto dropfrag; |
| 223 | frag6_nfragpackets++; |
| 224 | |
| 225 | q6 = kmem_intr_zalloc(sizeof(struct ip6q), KM_NOSLEEP); |
| 226 | if (q6 == NULL) { |
| 227 | goto dropfrag; |
| 228 | } |
| 229 | frag6_insque(q6, &ip6q); |
| 230 | |
| 231 | /* ip6q_nxt will be filled afterwards, from 1st fragment */ |
| 232 | q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; |
| 233 | #ifdef notyet |
| 234 | q6->ip6q_nxtp = (u_char *)nxtp; |
| 235 | #endif |
| 236 | q6->ip6q_ident = ip6f->ip6f_ident; |
| 237 | q6->ip6q_arrive = 0; /* Is it used anywhere? */ |
| 238 | q6->ip6q_ttl = IPV6_FRAGTTL; |
| 239 | q6->ip6q_src = ip6->ip6_src; |
| 240 | q6->ip6q_dst = ip6->ip6_dst; |
| 241 | q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ |
| 242 | |
| 243 | q6->ip6q_nfrag = 0; |
| 244 | } |
| 245 | |
| 246 | /* |
| 247 | * If it's the 1st fragment, record the length of the |
| 248 | * unfragmentable part and the next header of the fragment header. |
| 249 | */ |
| 250 | |
| 251 | if (fragoff == 0) { |
| 252 | q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - |
| 253 | sizeof(struct ip6_frag); |
| 254 | q6->ip6q_nxt = ip6f->ip6f_nxt; |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * Check that the reassembled packet would not exceed 65535 bytes |
| 259 | * in size. |
| 260 | * If it would exceed, discard the fragment and return an ICMP error. |
| 261 | */ |
| 262 | frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; |
| 263 | if (q6->ip6q_unfrglen >= 0) { |
| 264 | /* The 1st fragment has already arrived. */ |
| 265 | if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { |
| 266 | mutex_exit(&frag6_lock); |
| 267 | icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, |
| 268 | offset - sizeof(struct ip6_frag) + |
| 269 | offsetof(struct ip6_frag, ip6f_offlg)); |
| 270 | goto done; |
| 271 | } |
| 272 | } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { |
| 273 | mutex_exit(&frag6_lock); |
| 274 | icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, |
| 275 | offset - sizeof(struct ip6_frag) + |
| 276 | offsetof(struct ip6_frag, ip6f_offlg)); |
| 277 | goto done; |
| 278 | } |
| 279 | /* |
| 280 | * If it's the first fragment, do the above check for each |
| 281 | * fragment already stored in the reassembly queue. |
| 282 | */ |
| 283 | if (fragoff == 0) { |
| 284 | for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; |
| 285 | af6 = af6dwn) { |
| 286 | af6dwn = af6->ip6af_down; |
| 287 | |
| 288 | if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > |
| 289 | IPV6_MAXPACKET) { |
| 290 | struct mbuf *merr = IP6_REASS_MBUF(af6); |
| 291 | struct ip6_hdr *ip6err; |
| 292 | int erroff = af6->ip6af_offset; |
| 293 | |
| 294 | /* dequeue the fragment. */ |
| 295 | frag6_deq(af6); |
| 296 | kmem_intr_free(af6, sizeof(struct ip6asfrag)); |
| 297 | |
| 298 | /* adjust pointer. */ |
| 299 | ip6err = mtod(merr, struct ip6_hdr *); |
| 300 | |
| 301 | /* |
| 302 | * Restore source and destination addresses |
| 303 | * in the erroneous IPv6 header. |
| 304 | */ |
| 305 | ip6err->ip6_src = q6->ip6q_src; |
| 306 | ip6err->ip6_dst = q6->ip6q_dst; |
| 307 | |
| 308 | icmp6_error(merr, ICMP6_PARAM_PROB, |
| 309 | ICMP6_PARAMPROB_HEADER, |
| 310 | erroff - sizeof(struct ip6_frag) + |
| 311 | offsetof(struct ip6_frag, ip6f_offlg)); |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | ip6af = kmem_intr_zalloc(sizeof(struct ip6asfrag), KM_NOSLEEP); |
| 317 | if (ip6af == NULL) { |
| 318 | goto dropfrag; |
| 319 | } |
| 320 | ip6af->ip6af_head = ip6->ip6_flow; |
| 321 | ip6af->ip6af_len = ip6->ip6_plen; |
| 322 | ip6af->ip6af_nxt = ip6->ip6_nxt; |
| 323 | ip6af->ip6af_hlim = ip6->ip6_hlim; |
| 324 | ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; |
| 325 | ip6af->ip6af_off = fragoff; |
| 326 | ip6af->ip6af_frglen = frgpartlen; |
| 327 | ip6af->ip6af_offset = offset; |
| 328 | IP6_REASS_MBUF(ip6af) = m; |
| 329 | |
| 330 | if (first_frag) { |
| 331 | af6 = (struct ip6asfrag *)q6; |
| 332 | goto insert; |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * Find a segment which begins after this one does. |
| 337 | */ |
| 338 | for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; |
| 339 | af6 = af6->ip6af_down) |
| 340 | if (af6->ip6af_off > ip6af->ip6af_off) |
| 341 | break; |
| 342 | |
| 343 | /* |
| 344 | * If the incoming fragment overlaps some existing fragments in |
| 345 | * the reassembly queue - drop it as per RFC 5722. |
| 346 | */ |
| 347 | if (af6->ip6af_up != (struct ip6asfrag *)q6) { |
| 348 | i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen |
| 349 | - ip6af->ip6af_off; |
| 350 | if (i > 0) { |
| 351 | kmem_intr_free(ip6af, sizeof(struct ip6asfrag)); |
| 352 | goto dropfrag; |
| 353 | } |
| 354 | } |
| 355 | if (af6 != (struct ip6asfrag *)q6) { |
| 356 | i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; |
| 357 | if (i > 0) { |
| 358 | kmem_intr_free(ip6af, sizeof(struct ip6asfrag)); |
| 359 | goto dropfrag; |
| 360 | } |
| 361 | } |
| 362 | |
| 363 | insert: |
| 364 | |
| 365 | /* |
| 366 | * Stick new segment in its place; |
| 367 | * check for complete reassembly. |
| 368 | * Move to front of packet queue, as we are |
| 369 | * the most recently active fragmented packet. |
| 370 | */ |
| 371 | frag6_enq(ip6af, af6->ip6af_up); |
| 372 | frag6_nfrags++; |
| 373 | q6->ip6q_nfrag++; |
| 374 | #if 0 /* xxx */ |
| 375 | if (q6 != ip6q.ip6q_next) { |
| 376 | frag6_remque(q6); |
| 377 | frag6_insque(q6, &ip6q); |
| 378 | } |
| 379 | #endif |
| 380 | next = 0; |
| 381 | for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; |
| 382 | af6 = af6->ip6af_down) { |
| 383 | if (af6->ip6af_off != next) { |
| 384 | mutex_exit(&frag6_lock); |
| 385 | goto done; |
| 386 | } |
| 387 | next += af6->ip6af_frglen; |
| 388 | } |
| 389 | if (af6->ip6af_up->ip6af_mff) { |
| 390 | mutex_exit(&frag6_lock); |
| 391 | goto done; |
| 392 | } |
| 393 | |
| 394 | /* |
| 395 | * Reassembly is complete; concatenate fragments. |
| 396 | */ |
| 397 | ip6af = q6->ip6q_down; |
| 398 | t = m = IP6_REASS_MBUF(ip6af); |
| 399 | af6 = ip6af->ip6af_down; |
| 400 | frag6_deq(ip6af); |
| 401 | while (af6 != (struct ip6asfrag *)q6) { |
| 402 | af6dwn = af6->ip6af_down; |
| 403 | frag6_deq(af6); |
| 404 | while (t->m_next) |
| 405 | t = t->m_next; |
| 406 | t->m_next = IP6_REASS_MBUF(af6); |
| 407 | m_adj(t->m_next, af6->ip6af_offset); |
| 408 | kmem_intr_free(af6, sizeof(struct ip6asfrag)); |
| 409 | af6 = af6dwn; |
| 410 | } |
| 411 | |
| 412 | /* adjust offset to point where the original next header starts */ |
| 413 | offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); |
| 414 | kmem_intr_free(ip6af, sizeof(struct ip6asfrag)); |
| 415 | ip6 = mtod(m, struct ip6_hdr *); |
| 416 | ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr)); |
| 417 | ip6->ip6_src = q6->ip6q_src; |
| 418 | ip6->ip6_dst = q6->ip6q_dst; |
| 419 | nxt = q6->ip6q_nxt; |
| 420 | #ifdef notyet |
| 421 | *q6->ip6q_nxtp = (u_char)(nxt & 0xff); |
| 422 | #endif |
| 423 | |
| 424 | /* |
| 425 | * Delete frag6 header with as a few cost as possible. |
| 426 | */ |
| 427 | if (m->m_len >= offset + sizeof(struct ip6_frag)) { |
| 428 | memmove((char *)ip6 + sizeof(struct ip6_frag), ip6, offset); |
| 429 | m->m_data += sizeof(struct ip6_frag); |
| 430 | m->m_len -= sizeof(struct ip6_frag); |
| 431 | } else { |
| 432 | /* this comes with no copy if the boundary is on cluster */ |
| 433 | if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { |
| 434 | frag6_remque(q6); |
| 435 | frag6_nfrags -= q6->ip6q_nfrag; |
| 436 | kmem_intr_free(q6, sizeof(struct ip6q)); |
| 437 | frag6_nfragpackets--; |
| 438 | goto dropfrag; |
| 439 | } |
| 440 | m_adj(t, sizeof(struct ip6_frag)); |
| 441 | m_cat(m, t); |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Store NXT to the original. |
| 446 | */ |
| 447 | { |
| 448 | u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ |
| 449 | *prvnxtp = nxt; |
| 450 | } |
| 451 | |
| 452 | frag6_remque(q6); |
| 453 | frag6_nfrags -= q6->ip6q_nfrag; |
| 454 | kmem_intr_free(q6, sizeof(struct ip6q)); |
| 455 | frag6_nfragpackets--; |
| 456 | |
| 457 | if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ |
| 458 | int plen = 0; |
| 459 | for (t = m; t; t = t->m_next) |
| 460 | plen += t->m_len; |
| 461 | m->m_pkthdr.len = plen; |
| 462 | } |
| 463 | |
| 464 | IP6_STATINC(IP6_STAT_REASSEMBLED); |
| 465 | in6_ifstat_inc(dstifp, ifs6_reass_ok); |
| 466 | |
| 467 | /* |
| 468 | * Tell launch routine the next header |
| 469 | */ |
| 470 | |
| 471 | *mp = m; |
| 472 | *offp = offset; |
| 473 | |
| 474 | mutex_exit(&frag6_lock); |
| 475 | return nxt; |
| 476 | |
| 477 | dropfrag: |
| 478 | mutex_exit(&frag6_lock); |
| 479 | in6_ifstat_inc(dstifp, ifs6_reass_fail); |
| 480 | IP6_STATINC(IP6_STAT_FRAGDROPPED); |
| 481 | m_freem(m); |
| 482 | done: |
| 483 | return IPPROTO_DONE; |
| 484 | } |
| 485 | |
| 486 | int |
| 487 | ip6_reass_packet(struct mbuf **mp, int offset) |
| 488 | { |
| 489 | |
| 490 | if (frag6_input(mp, &offset, IPPROTO_IPV6) == IPPROTO_DONE) { |
| 491 | *mp = NULL; |
| 492 | return EINVAL; |
| 493 | } |
| 494 | return 0; |
| 495 | } |
| 496 | |
| 497 | /* |
| 498 | * Free a fragment reassembly header and all |
| 499 | * associated datagrams. |
| 500 | */ |
| 501 | void |
| 502 | frag6_freef(struct ip6q *q6) |
| 503 | { |
| 504 | struct ip6asfrag *af6, *down6; |
| 505 | |
| 506 | KASSERT(mutex_owned(&frag6_lock)); |
| 507 | |
| 508 | for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; |
| 509 | af6 = down6) { |
| 510 | struct mbuf *m = IP6_REASS_MBUF(af6); |
| 511 | |
| 512 | down6 = af6->ip6af_down; |
| 513 | frag6_deq(af6); |
| 514 | |
| 515 | /* |
| 516 | * Return ICMP time exceeded error for the 1st fragment. |
| 517 | * Just free other fragments. |
| 518 | */ |
| 519 | if (af6->ip6af_off == 0) { |
| 520 | struct ip6_hdr *ip6; |
| 521 | |
| 522 | /* adjust pointer */ |
| 523 | ip6 = mtod(m, struct ip6_hdr *); |
| 524 | |
| 525 | /* restoure source and destination addresses */ |
| 526 | ip6->ip6_src = q6->ip6q_src; |
| 527 | ip6->ip6_dst = q6->ip6q_dst; |
| 528 | |
| 529 | icmp6_error(m, ICMP6_TIME_EXCEEDED, |
| 530 | ICMP6_TIME_EXCEED_REASSEMBLY, 0); |
| 531 | } else { |
| 532 | m_freem(m); |
| 533 | } |
| 534 | kmem_intr_free(af6, sizeof(struct ip6asfrag)); |
| 535 | } |
| 536 | frag6_remque(q6); |
| 537 | frag6_nfrags -= q6->ip6q_nfrag; |
| 538 | kmem_intr_free(q6, sizeof(struct ip6q)); |
| 539 | frag6_nfragpackets--; |
| 540 | } |
| 541 | |
| 542 | /* |
| 543 | * Put an ip fragment on a reassembly chain. |
| 544 | * Like insque, but pointers in middle of structure. |
| 545 | */ |
| 546 | void |
| 547 | frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) |
| 548 | { |
| 549 | |
| 550 | KASSERT(mutex_owned(&frag6_lock)); |
| 551 | |
| 552 | af6->ip6af_up = up6; |
| 553 | af6->ip6af_down = up6->ip6af_down; |
| 554 | up6->ip6af_down->ip6af_up = af6; |
| 555 | up6->ip6af_down = af6; |
| 556 | } |
| 557 | |
| 558 | /* |
| 559 | * To frag6_enq as remque is to insque. |
| 560 | */ |
| 561 | void |
| 562 | frag6_deq(struct ip6asfrag *af6) |
| 563 | { |
| 564 | |
| 565 | KASSERT(mutex_owned(&frag6_lock)); |
| 566 | |
| 567 | af6->ip6af_up->ip6af_down = af6->ip6af_down; |
| 568 | af6->ip6af_down->ip6af_up = af6->ip6af_up; |
| 569 | } |
| 570 | |
| 571 | void |
| 572 | frag6_insque(struct ip6q *newq, struct ip6q *oldq) |
| 573 | { |
| 574 | |
| 575 | KASSERT(mutex_owned(&frag6_lock)); |
| 576 | |
| 577 | newq->ip6q_prev = oldq; |
| 578 | newq->ip6q_next = oldq->ip6q_next; |
| 579 | oldq->ip6q_next->ip6q_prev= newq; |
| 580 | oldq->ip6q_next = newq; |
| 581 | } |
| 582 | |
| 583 | void |
| 584 | frag6_remque(struct ip6q *p6) |
| 585 | { |
| 586 | |
| 587 | KASSERT(mutex_owned(&frag6_lock)); |
| 588 | |
| 589 | p6->ip6q_prev->ip6q_next = p6->ip6q_next; |
| 590 | p6->ip6q_next->ip6q_prev = p6->ip6q_prev; |
| 591 | } |
| 592 | |
| 593 | void |
| 594 | frag6_fasttimo(void) |
| 595 | { |
| 596 | mutex_enter(softnet_lock); |
| 597 | KERNEL_LOCK(1, NULL); |
| 598 | |
| 599 | if (frag6_drainwanted) { |
| 600 | frag6_drain(); |
| 601 | frag6_drainwanted = 0; |
| 602 | } |
| 603 | |
| 604 | KERNEL_UNLOCK_ONE(NULL); |
| 605 | mutex_exit(softnet_lock); |
| 606 | } |
| 607 | |
| 608 | /* |
| 609 | * IPv6 reassembling timer processing; |
| 610 | * if a timer expires on a reassembly |
| 611 | * queue, discard it. |
| 612 | */ |
| 613 | void |
| 614 | frag6_slowtimo(void) |
| 615 | { |
| 616 | struct ip6q *q6; |
| 617 | |
| 618 | mutex_enter(softnet_lock); |
| 619 | KERNEL_LOCK(1, NULL); |
| 620 | |
| 621 | mutex_enter(&frag6_lock); |
| 622 | q6 = ip6q.ip6q_next; |
| 623 | if (q6) |
| 624 | while (q6 != &ip6q) { |
| 625 | --q6->ip6q_ttl; |
| 626 | q6 = q6->ip6q_next; |
| 627 | if (q6->ip6q_prev->ip6q_ttl == 0) { |
| 628 | IP6_STATINC(IP6_STAT_FRAGTIMEOUT); |
| 629 | /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ |
| 630 | frag6_freef(q6->ip6q_prev); |
| 631 | } |
| 632 | } |
| 633 | /* |
| 634 | * If we are over the maximum number of fragments |
| 635 | * (due to the limit being lowered), drain off |
| 636 | * enough to get down to the new limit. |
| 637 | */ |
| 638 | while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && |
| 639 | ip6q.ip6q_prev) { |
| 640 | IP6_STATINC(IP6_STAT_FRAGOVERFLOW); |
| 641 | /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ |
| 642 | frag6_freef(ip6q.ip6q_prev); |
| 643 | } |
| 644 | mutex_exit(&frag6_lock); |
| 645 | |
| 646 | KERNEL_UNLOCK_ONE(NULL); |
| 647 | mutex_exit(softnet_lock); |
| 648 | |
| 649 | #if 0 |
| 650 | /* |
| 651 | * Routing changes might produce a better route than we last used; |
| 652 | * make sure we notice eventually, even if forwarding only for one |
| 653 | * destination and the cache is never replaced. |
| 654 | */ |
| 655 | rtcache_free(&ip6_forward_rt); |
| 656 | rtcache_free(&ipsrcchk_rt); |
| 657 | #endif |
| 658 | |
| 659 | } |
| 660 | |
| 661 | void |
| 662 | frag6_drainstub(void) |
| 663 | { |
| 664 | frag6_drainwanted = 1; |
| 665 | } |
| 666 | |
| 667 | /* |
| 668 | * Drain off all datagram fragments. |
| 669 | */ |
| 670 | void |
| 671 | frag6_drain(void) |
| 672 | { |
| 673 | |
| 674 | if (mutex_tryenter(&frag6_lock)) { |
| 675 | while (ip6q.ip6q_next != &ip6q) { |
| 676 | IP6_STATINC(IP6_STAT_FRAGDROPPED); |
| 677 | /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ |
| 678 | frag6_freef(ip6q.ip6q_next); |
| 679 | } |
| 680 | mutex_exit(&frag6_lock); |
| 681 | } |
| 682 | } |
| 683 | |