1 /* $NetBSD: ip6_flow.c,v 1.9 2007/08/20 19:42:34 dyoung Exp $ */ 2 3 /*- 4 * Copyright (c) 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by the 3am Software Foundry ("3am"). It was developed by Liam J. Foy 9 * <liamjfoy@netbsd.org> and Matt Thomas <matt@netbsd.org>. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 * 39 * IPv6 version was developed by Liam J. Foy. Original source existed in IPv4 40 * format developed by Matt Thomas. Thanks to Joerg Sonnenberger, Matt 41 * Thomas and Christos Zoulas. 42 * 43 * Thanks to Liverpool John Moores University, especially Dr. David Llewellyn-Jones 44 * for providing resources (to test) and Professor Madjid Merabti. 45 */ 46 47 #include <sys/cdefs.h> 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/malloc.h> 52 #include <sys/mbuf.h> 53 #include <sys/domain.h> 54 #include <sys/protosw.h> 55 #include <sys/socket.h> 56 #include <sys/socketvar.h> 57 #include <sys/time.h> 58 #include <sys/kernel.h> 59 #include <sys/pool.h> 60 #include <sys/sysctl.h> 61 62 #include <net/if.h> 63 #include <net/if_dl.h> 64 #include <net/route.h> 65 #include <net/pfil.h> 66 67 #include <netinet/in.h> 68 #include <netinet6/in6_var.h> 69 #include <netinet/in_systm.h> 70 #include <netinet/ip6.h> 71 #include <netinet6/ip6_var.h> 72 73 /* 74 * IPv6 Fast Forward caches/hashes flows from one source to destination. 75 * 76 * Upon a successful forward IPv6FF caches and hashes details such as the 77 * route, source and destination. Once another packet is received matching 78 * the source and destination the packet is forwarded straight onto if_output 79 * using the cached details. 80 * 81 * Example: 82 * ether/fddi_input -> ip6flow_fastfoward -> if_output 83 */ 84 85 POOL_INIT(ip6flow_pool, sizeof(struct ip6flow), 0, 0, 0, "ip6flowpl", NULL, 86 IPL_NET); 87 88 LIST_HEAD(ip6flowhead, ip6flow); 89 90 /* 91 * We could use IPv4 defines (IPFLOW_HASHBITS) but we'll 92 * use our own (possibly for future expansion). 93 */ 94 #define IP6FLOW_TIMER (5 * PR_SLOWHZ) 95 #define IP6FLOW_DEFAULT_HASHSIZE (1 << IP6FLOW_HASHBITS) 96 97 static struct ip6flowhead *ip6flowtable = NULL; 98 static struct ip6flowhead ip6flowlist; 99 static int ip6flow_inuse; 100 101 /* 102 * Insert an ip6flow into the list. 103 */ 104 #define IP6FLOW_INSERT(bucket, ip6f) \ 105 do { \ 106 LIST_INSERT_HEAD((bucket), (ip6f), ip6f_hash); \ 107 LIST_INSERT_HEAD(&ip6flowlist, (ip6f), ip6f_list); \ 108 } while (/*CONSTCOND*/ 0) 109 110 /* 111 * Remove an ip6flow from the list. 112 */ 113 #define IP6FLOW_REMOVE(ip6f) \ 114 do { \ 115 LIST_REMOVE((ip6f), ip6f_hash); \ 116 LIST_REMOVE((ip6f), ip6f_list); \ 117 } while (/*CONSTCOND*/ 0) 118 119 #ifndef IP6FLOW_DEFAULT 120 #define IP6FLOW_DEFAULT 256 121 #endif 122 123 int ip6_maxflows = IP6FLOW_DEFAULT; 124 int ip6_hashsize = IP6FLOW_DEFAULT_HASHSIZE; 125 126 /* 127 * Calculate hash table position. 128 */ 129 static size_t 130 ip6flow_hash(struct ip6_hdr *ip6) 131 { 132 size_t hash; 133 uint32_t dst_sum, src_sum; 134 size_t idx; 135 136 src_sum = ip6->ip6_src.s6_addr32[0] + ip6->ip6_src.s6_addr32[1] 137 + ip6->ip6_src.s6_addr32[2] + ip6->ip6_src.s6_addr32[3]; 138 dst_sum = ip6->ip6_dst.s6_addr32[0] + ip6->ip6_dst.s6_addr32[1] 139 + ip6->ip6_dst.s6_addr32[2] + ip6->ip6_dst.s6_addr32[3]; 140 141 hash = ip6->ip6_flow; 142 143 for (idx = 0; idx < 32; idx += IP6FLOW_HASHBITS) 144 hash += (dst_sum >> (32 - idx)) + (src_sum >> idx); 145 146 return hash & (ip6_hashsize-1); 147 } 148 149 /* 150 * Check to see if a flow already exists - if so return it. 151 */ 152 static struct ip6flow * 153 ip6flow_lookup(struct ip6_hdr *ip6) 154 { 155 size_t hash; 156 struct ip6flow *ip6f; 157 158 hash = ip6flow_hash(ip6); 159 160 LIST_FOREACH(ip6f, &ip6flowtable[hash], ip6f_hash) { 161 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6f->ip6f_dst) 162 && IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6f->ip6f_src) 163 && ip6f->ip6f_flow == ip6->ip6_flow) { 164 /* A cached flow has been found. */ 165 return ip6f; 166 } 167 } 168 169 return NULL; 170 } 171 172 /* 173 * Allocate memory and initialise lists. This function is called 174 * from ip6_init and called there after to resize the hash table. 175 * If a newly sized table cannot be malloc'ed we just continue 176 * to use the old one. 177 */ 178 int 179 ip6flow_init(int table_size) 180 { 181 struct ip6flowhead *new_table; 182 size_t i; 183 184 new_table = (struct ip6flowhead *)malloc(sizeof(struct ip6flowhead) * 185 table_size, M_RTABLE, M_NOWAIT); 186 187 if (new_table == NULL) 188 return 1; 189 190 if (ip6flowtable != NULL) 191 free(ip6flowtable, M_RTABLE); 192 193 ip6flowtable = new_table; 194 ip6_hashsize = table_size; 195 196 LIST_INIT(&ip6flowlist); 197 for (i = 0; i < ip6_hashsize; i++) 198 LIST_INIT(&ip6flowtable[i]); 199 200 return 0; 201 } 202 203 /* 204 * IPv6 Fast Forward routine. Attempt to forward the packet - 205 * if any problems are found return to the main IPv6 input 206 * routine to deal with. 207 */ 208 int 209 ip6flow_fastforward(struct mbuf *m) 210 { 211 struct ip6flow *ip6f; 212 struct ip6_hdr *ip6; 213 struct rtentry *rt; 214 const struct sockaddr *dst; 215 int error; 216 217 /* 218 * Are we forwarding packets and have flows? 219 */ 220 if (!ip6_forwarding || ip6flow_inuse == 0) 221 return 0; 222 223 /* 224 * At least size of IPv6 Header? 225 */ 226 if (m->m_len < sizeof(struct ip6_hdr)) 227 return 0; 228 /* 229 * Was packet received as a link-level multicast or broadcast? 230 * If so, don't try to fast forward. 231 */ 232 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0) 233 return 0; 234 235 if (IP6_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 236 if ((m = m_copyup(m, sizeof(struct ip6_hdr), 237 (max_linkhdr + 3) & ~3)) == NULL) { 238 return 0; 239 } 240 } else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) { 241 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { 242 return 0; 243 } 244 } 245 246 ip6 = mtod(m, struct ip6_hdr *); 247 248 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) { 249 /* Bad version. */ 250 return 0; 251 } 252 253 /* 254 * If we have a hop-by-hop extension we must process it. 255 * We just leave this up to ip6_input to deal with. 256 */ 257 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) 258 return 0; 259 260 /* 261 * Attempt to find a flow. 262 */ 263 if ((ip6f = ip6flow_lookup(ip6)) == NULL) { 264 /* No flow found. */ 265 return 0; 266 } 267 268 /* 269 * Route and interface still up? 270 */ 271 if (rtcache_down(&ip6f->ip6f_ro) || 272 (rt = ip6f->ip6f_ro.ro_rt) == NULL || 273 (rt->rt_ifp->if_flags & IFF_UP) == 0) { 274 /* Route or interface is down */ 275 return 0; 276 } 277 278 /* 279 * Packet size greater than MTU? 280 */ 281 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 282 /* Return to main IPv6 input function. */ 283 return 0; 284 } 285 286 if (ip6->ip6_hlim <= IPV6_HLIMDEC) 287 return 0; 288 289 /* Decrement hop limit (same as TTL) */ 290 ip6->ip6_hlim -= IPV6_HLIMDEC; 291 292 if (rt->rt_flags & RTF_GATEWAY) 293 dst = rt->rt_gateway; 294 else 295 dst = rtcache_getdst(&ip6f->ip6f_ro); 296 297 PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER); 298 299 ip6f->ip6f_uses++; 300 301 /* Send on its way - straight to the interface output routine. */ 302 if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) { 303 ip6f->ip6f_dropped++; 304 } else { 305 ip6f->ip6f_forwarded++; 306 } 307 308 return 1; 309 } 310 311 /* 312 * Add the IPv6 flow statistics to the main IPv6 statistics. 313 */ 314 static void 315 ip6flow_addstats(struct ip6flow *ip6f) 316 { 317 if (!rtcache_down(&ip6f->ip6f_ro) && ip6f->ip6f_ro.ro_rt != NULL) 318 ip6f->ip6f_ro.ro_rt->rt_use += ip6f->ip6f_uses; 319 ip6stat.ip6s_fastforwardflows = ip6flow_inuse; 320 ip6stat.ip6s_cantforward += ip6f->ip6f_dropped; 321 ip6stat.ip6s_odropped += ip6f->ip6f_dropped; 322 ip6stat.ip6s_total += ip6f->ip6f_uses; 323 ip6stat.ip6s_forward += ip6f->ip6f_forwarded; 324 ip6stat.ip6s_fastforward += ip6f->ip6f_forwarded; 325 } 326 327 /* 328 * Add statistics and free the flow. 329 */ 330 static void 331 ip6flow_free(struct ip6flow *ip6f) 332 { 333 int s; 334 335 /* 336 * Remove the flow from the hash table (at elevated IPL). 337 * Once it's off the list, we can deal with it at normal 338 * network IPL. 339 */ 340 s = splnet(); 341 IP6FLOW_REMOVE(ip6f); 342 splx(s); 343 ip6flow_inuse--; 344 ip6flow_addstats(ip6f); 345 rtcache_free(&ip6f->ip6f_ro); 346 pool_put(&ip6flow_pool, ip6f); 347 } 348 349 /* 350 * Reap one or more flows - ip6flow_reap may remove 351 * multiple flows if net.inet6.ip6.maxflows is reduced. 352 */ 353 struct ip6flow * 354 ip6flow_reap(int just_one) 355 { 356 while (just_one || ip6flow_inuse > ip6_maxflows) { 357 struct ip6flow *ip6f, *maybe_ip6f = NULL; 358 int s; 359 360 ip6f = LIST_FIRST(&ip6flowlist); 361 while (ip6f != NULL) { 362 /* 363 * If this no longer points to a valid route - 364 * reclaim it. 365 */ 366 if (rtcache_down(&ip6f->ip6f_ro) || 367 ip6f->ip6f_ro.ro_rt == NULL) 368 goto done; 369 /* 370 * choose the one that's been least recently 371 * used or has had the least uses in the 372 * last 1.5 intervals. 373 */ 374 if (maybe_ip6f == NULL || 375 ip6f->ip6f_timer < maybe_ip6f->ip6f_timer || 376 (ip6f->ip6f_timer == maybe_ip6f->ip6f_timer && 377 ip6f->ip6f_last_uses + ip6f->ip6f_uses < 378 maybe_ip6f->ip6f_last_uses + 379 maybe_ip6f->ip6f_uses)) 380 maybe_ip6f = ip6f; 381 ip6f = LIST_NEXT(ip6f, ip6f_list); 382 } 383 ip6f = maybe_ip6f; 384 done: 385 /* 386 * Remove the entry from the flow table 387 */ 388 s = splnet(); 389 IP6FLOW_REMOVE(ip6f); 390 splx(s); 391 rtcache_free(&ip6f->ip6f_ro); 392 if (just_one) { 393 ip6flow_addstats(ip6f); 394 return ip6f; 395 } 396 ip6flow_inuse--; 397 ip6flow_addstats(ip6f); 398 pool_put(&ip6flow_pool, ip6f); 399 } 400 return NULL; 401 } 402 403 void 404 ip6flow_slowtimo(void) 405 { 406 struct ip6flow *ip6f, *next_ip6f; 407 408 for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) { 409 next_ip6f = LIST_NEXT(ip6f, ip6f_list); 410 if (PRT_SLOW_ISEXPIRED(ip6f->ip6f_timer) || 411 rtcache_down(&ip6f->ip6f_ro) || 412 ip6f->ip6f_ro.ro_rt == NULL) { 413 ip6flow_free(ip6f); 414 } else { 415 ip6f->ip6f_last_uses = ip6f->ip6f_uses; 416 ip6flow_addstats(ip6f); 417 ip6f->ip6f_uses = 0; 418 ip6f->ip6f_dropped = 0; 419 ip6f->ip6f_forwarded = 0; 420 } 421 } 422 } 423 424 /* 425 * We have successfully forwarded a packet using the normal 426 * IPv6 stack. Now create/update a flow. 427 */ 428 void 429 ip6flow_create(const struct route *ro, struct mbuf *m) 430 { 431 struct ip6_hdr *ip6; 432 struct ip6flow *ip6f; 433 size_t hash; 434 int s; 435 436 ip6 = mtod(m, struct ip6_hdr *); 437 438 /* 439 * If IPv6 Fast Forward is disabled, don't create a flow. 440 * It can be disabled by setting net.inet6.ip6.maxflows to 0. 441 * 442 * Don't create a flow for ICMPv6 messages. 443 */ 444 if (ip6_maxflows == 0 || ip6->ip6_nxt == IPPROTO_IPV6_ICMP) 445 return; 446 447 /* 448 * See if an existing flow exists. If so: 449 * - Remove the flow 450 * - Add flow statistics 451 * - Free the route 452 * - Reset statistics 453 * 454 * If a flow doesn't exist allocate a new one if 455 * ip6_maxflows hasn't reached its limit. If it has 456 * been reached, reap some flows. 457 */ 458 ip6f = ip6flow_lookup(ip6); 459 if (ip6f == NULL) { 460 if (ip6flow_inuse >= ip6_maxflows) { 461 ip6f = ip6flow_reap(1); 462 } else { 463 ip6f = pool_get(&ip6flow_pool, PR_NOWAIT); 464 if (ip6f == NULL) 465 return; 466 ip6flow_inuse++; 467 } 468 memset(ip6f, 0, sizeof(*ip6f)); 469 } else { 470 s = splnet(); 471 IP6FLOW_REMOVE(ip6f); 472 splx(s); 473 ip6flow_addstats(ip6f); 474 rtcache_free(&ip6f->ip6f_ro); 475 ip6f->ip6f_uses = 0; 476 ip6f->ip6f_last_uses = 0; 477 ip6f->ip6f_dropped = 0; 478 ip6f->ip6f_forwarded = 0; 479 } 480 481 /* 482 * Fill in the updated/new details. 483 */ 484 rtcache_copy(&ip6f->ip6f_ro, ro); 485 ip6f->ip6f_dst = ip6->ip6_dst; 486 ip6f->ip6f_src = ip6->ip6_src; 487 ip6f->ip6f_flow = ip6->ip6_flow; 488 PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER); 489 ip6f->ip6f_start = time_uptime; 490 491 /* 492 * Insert into the approriate bucket of the flow table. 493 */ 494 hash = ip6flow_hash(ip6); 495 s = splnet(); 496 IP6FLOW_INSERT(&ip6flowtable[hash], ip6f); 497 splx(s); 498 } 499 500 /* 501 * Invalidate/remove all flows - if new_size is positive we 502 * resize the hash table. 503 */ 504 int 505 ip6flow_invalidate_all(int new_size) 506 { 507 struct ip6flow *ip6f, *next_ip6f; 508 int s, error; 509 510 error = 0; 511 s = splnet(); 512 for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) { 513 next_ip6f = LIST_NEXT(ip6f, ip6f_list); 514 ip6flow_free(ip6f); 515 } 516 517 if (new_size) 518 error = ip6flow_init(new_size); 519 splx(s); 520 521 return error; 522 } 523