1/* $NetBSD: ip6_flow.c,v 1.19.2.1 2012/10/31 16:07:46 riz 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 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 * 32 * IPv6 version was developed by Liam J. Foy. Original source existed in IPv4 33 * format developed by Matt Thomas. Thanks to Joerg Sonnenberger, Matt 34 * Thomas and Christos Zoulas. 35 * 36 * Thanks to Liverpool John Moores University, especially Dr. David Llewellyn-Jones 37 * for providing resources (to test) and Professor Madjid Merabti. 38 */ 39 40#include <sys/cdefs.h> 41__KERNEL_RCSID(0, "$NetBSD: ip6_flow.c,v 1.19.2.1 2012/10/31 16:07:46 riz Exp $"); 42 43#include <sys/param.h> 44#include <sys/systm.h> 45#include <sys/malloc.h> 46#include <sys/mbuf.h> 47#include <sys/domain.h> 48#include <sys/protosw.h> 49#include <sys/socket.h> 50#include <sys/socketvar.h> 51#include <sys/time.h> 52#include <sys/kernel.h> 53#include <sys/pool.h> 54#include <sys/sysctl.h> 55 56#include <net/if.h> 57#include <net/if_dl.h> 58#include <net/route.h> 59#include <net/pfil.h> 60 61#include <netinet/in.h> 62#include <netinet6/in6_var.h> 63#include <netinet/in_systm.h> 64#include <netinet/ip6.h> 65#include <netinet6/ip6_var.h> 66#include <netinet6/ip6_private.h> 67 68/* 69 * IPv6 Fast Forward caches/hashes flows from one source to destination. 70 * 71 * Upon a successful forward IPv6FF caches and hashes details such as the 72 * route, source and destination. Once another packet is received matching 73 * the source and destination the packet is forwarded straight onto if_output 74 * using the cached details. 75 * 76 * Example: 77 * ether/fddi_input -> ip6flow_fastforward -> if_output 78 */ 79 80static struct pool ip6flow_pool; 81 82LIST_HEAD(ip6flowhead, ip6flow); 83 84/* 85 * We could use IPv4 defines (IPFLOW_HASHBITS) but we'll 86 * use our own (possibly for future expansion). 87 */ 88#define IP6FLOW_TIMER (5 * PR_SLOWHZ) 89#define IP6FLOW_DEFAULT_HASHSIZE (1 << IP6FLOW_HASHBITS) 90 91static struct ip6flowhead *ip6flowtable = NULL; 92static struct ip6flowhead ip6flowlist; 93static int ip6flow_inuse; 94 95/* 96 * Insert an ip6flow into the list. 97 */ 98#define IP6FLOW_INSERT(bucket, ip6f) \ 99do { \ 100 LIST_INSERT_HEAD((bucket), (ip6f), ip6f_hash); \ 101 LIST_INSERT_HEAD(&ip6flowlist, (ip6f), ip6f_list); \ 102} while (/*CONSTCOND*/ 0) 103 104/* 105 * Remove an ip6flow from the list. 106 */ 107#define IP6FLOW_REMOVE(ip6f) \ 108do { \ 109 LIST_REMOVE((ip6f), ip6f_hash); \ 110 LIST_REMOVE((ip6f), ip6f_list); \ 111} while (/*CONSTCOND*/ 0) 112 113#ifndef IP6FLOW_DEFAULT 114#define IP6FLOW_DEFAULT 256 115#endif 116 117int ip6_maxflows = IP6FLOW_DEFAULT; 118int ip6_hashsize = IP6FLOW_DEFAULT_HASHSIZE; 119 120/* 121 * Calculate hash table position. 122 */ 123static size_t 124ip6flow_hash(const struct ip6_hdr *ip6) 125{ 126 size_t hash; 127 uint32_t dst_sum, src_sum; 128 size_t idx; 129 130 src_sum = ip6->ip6_src.s6_addr32[0] + ip6->ip6_src.s6_addr32[1] 131 + ip6->ip6_src.s6_addr32[2] + ip6->ip6_src.s6_addr32[3]; 132 dst_sum = ip6->ip6_dst.s6_addr32[0] + ip6->ip6_dst.s6_addr32[1] 133 + ip6->ip6_dst.s6_addr32[2] + ip6->ip6_dst.s6_addr32[3]; 134 135 hash = ip6->ip6_flow; 136 137 for (idx = 0; idx < 32; idx += IP6FLOW_HASHBITS) 138 hash += (dst_sum >> (32 - idx)) + (src_sum >> idx); 139 140 return hash & (ip6_hashsize-1); 141} 142 143/* 144 * Check to see if a flow already exists - if so return it. 145 */ 146static struct ip6flow * 147ip6flow_lookup(const struct ip6_hdr *ip6) 148{ 149 size_t hash; 150 struct ip6flow *ip6f; 151 152 hash = ip6flow_hash(ip6); 153 154 LIST_FOREACH(ip6f, &ip6flowtable[hash], ip6f_hash) { 155 if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6f->ip6f_dst) 156 && IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6f->ip6f_src) 157 && ip6f->ip6f_flow == ip6->ip6_flow) { 158 /* A cached flow has been found. */ 159 return ip6f; 160 } 161 } 162 163 return NULL; 164} 165 166void 167ip6flow_poolinit(void) 168{ 169 170 pool_init(&ip6flow_pool, sizeof(struct ip6flow), 0, 0, 0, "ip6flowpl", 171 NULL, IPL_NET); 172} 173 174/* 175 * Allocate memory and initialise lists. This function is called 176 * from ip6_init and called there after to resize the hash table. 177 * If a newly sized table cannot be malloc'ed we just continue 178 * to use the old one. 179 */ 180int 181ip6flow_init(int table_size) 182{ 183 struct ip6flowhead *new_table; 184 size_t i; 185 186 new_table = (struct ip6flowhead *)malloc(sizeof(struct ip6flowhead) * 187 table_size, M_RTABLE, M_NOWAIT); 188 189 if (new_table == NULL) 190 return 1; 191 192 if (ip6flowtable != NULL) 193 free(ip6flowtable, M_RTABLE); 194 195 ip6flowtable = new_table; 196 ip6_hashsize = table_size; 197 198 LIST_INIT(&ip6flowlist); 199 for (i = 0; i < ip6_hashsize; i++) 200 LIST_INIT(&ip6flowtable[i]); 201 202 return 0; 203} 204 205/* 206 * IPv6 Fast Forward routine. Attempt to forward the packet - 207 * if any problems are found return to the main IPv6 input 208 * routine to deal with. 209 */ 210int 211ip6flow_fastforward(struct mbuf **mp) 212{ 213 struct ip6flow *ip6f; 214 struct ip6_hdr *ip6; 215 struct rtentry *rt; 216 struct mbuf *m; 217 const struct sockaddr *dst; 218 int error; 219 220 /* 221 * Are we forwarding packets and have flows? 222 */ 223 if (!ip6_forwarding || ip6flow_inuse == 0) 224 return 0; 225 226 m = *mp; 227 /* 228 * At least size of IPv6 Header? 229 */ 230 if (m->m_len < sizeof(struct ip6_hdr)) 231 return 0; 232 /* 233 * Was packet received as a link-level multicast or broadcast? 234 * If so, don't try to fast forward. 235 */ 236 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0) 237 return 0; 238 239 if (IP6_HDR_ALIGNED_P(mtod(m, const void *)) == 0) { 240 if ((m = m_copyup(m, sizeof(struct ip6_hdr), 241 (max_linkhdr + 3) & ~3)) == NULL) { 242 return 0; 243 } 244 *mp = m; 245 } else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) { 246 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { 247 return 0; 248 } 249 *mp = m; 250 } 251 252 ip6 = mtod(m, struct ip6_hdr *); 253 254 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) { 255 /* Bad version. */ 256 return 0; 257 } 258 259 /* 260 * If we have a hop-by-hop extension we must process it. 261 * We just leave this up to ip6_input to deal with. 262 */ 263 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) 264 return 0; 265 266 /* 267 * Attempt to find a flow. 268 */ 269 if ((ip6f = ip6flow_lookup(ip6)) == NULL) { 270 /* No flow found. */ 271 return 0; 272 } 273 274 /* 275 * Route and interface still up? 276 */ 277 if ((rt = rtcache_validate(&ip6f->ip6f_ro)) == NULL || 278 (rt->rt_ifp->if_flags & IFF_UP) == 0) { 279 /* Route or interface is down */ 280 return 0; 281 } 282 283 /* 284 * Packet size greater than MTU? 285 */ 286 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 287 /* Return to main IPv6 input function. */ 288 return 0; 289 } 290 291 if (ip6->ip6_hlim <= IPV6_HLIMDEC) 292 return 0; 293 294 /* Decrement hop limit (same as TTL) */ 295 ip6->ip6_hlim -= IPV6_HLIMDEC; 296 297 if (rt->rt_flags & RTF_GATEWAY) 298 dst = rt->rt_gateway; 299 else 300 dst = rtcache_getdst(&ip6f->ip6f_ro); 301 302 PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER); 303 304 ip6f->ip6f_uses++; 305 306 KERNEL_LOCK(1, NULL); 307 /* Send on its way - straight to the interface output routine. */ 308 if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) { 309 ip6f->ip6f_dropped++; 310 } else { 311 ip6f->ip6f_forwarded++; 312 } 313 KERNEL_UNLOCK_ONE(NULL); 314 return 1; 315} 316 317/* 318 * Add the IPv6 flow statistics to the main IPv6 statistics. 319 */ 320static void 321ip6flow_addstats(const struct ip6flow *ip6f) 322{ 323 struct rtentry *rt; 324 uint64_t *ip6s; 325 326 if ((rt = rtcache_validate(&ip6f->ip6f_ro)) != NULL) 327 rt->rt_use += ip6f->ip6f_uses; 328 ip6s = IP6_STAT_GETREF(); 329 ip6s[IP6_STAT_FASTFORWARDFLOWS] = ip6flow_inuse; 330 ip6s[IP6_STAT_CANTFORWARD] += ip6f->ip6f_dropped; 331 ip6s[IP6_STAT_ODROPPED] += ip6f->ip6f_dropped; 332 ip6s[IP6_STAT_TOTAL] += ip6f->ip6f_uses; 333 ip6s[IP6_STAT_FORWARD] += ip6f->ip6f_forwarded; 334 ip6s[IP6_STAT_FASTFORWARD] += ip6f->ip6f_forwarded; 335 IP6_STAT_PUTREF(); 336} 337 338/* 339 * Add statistics and free the flow. 340 */ 341static void 342ip6flow_free(struct ip6flow *ip6f) 343{ 344 int s; 345 346 /* 347 * Remove the flow from the hash table (at elevated IPL). 348 * Once it's off the list, we can deal with it at normal 349 * network IPL. 350 */ 351 s = splnet(); 352 IP6FLOW_REMOVE(ip6f); 353 splx(s); 354 ip6flow_inuse--; 355 ip6flow_addstats(ip6f); 356 rtcache_free(&ip6f->ip6f_ro); 357 pool_put(&ip6flow_pool, ip6f); 358} 359 360/* 361 * Reap one or more flows - ip6flow_reap may remove 362 * multiple flows if net.inet6.ip6.maxflows is reduced. 363 */ 364struct ip6flow * 365ip6flow_reap(int just_one) 366{ 367 while (just_one || ip6flow_inuse > ip6_maxflows) { 368 struct ip6flow *ip6f, *maybe_ip6f = NULL; 369 int s; 370 371 ip6f = LIST_FIRST(&ip6flowlist); 372 while (ip6f != NULL) { 373 /* 374 * If this no longer points to a valid route - 375 * reclaim it. 376 */ 377 if (rtcache_validate(&ip6f->ip6f_ro) == NULL) 378 goto done; 379 /* 380 * choose the one that's been least recently 381 * used or has had the least uses in the 382 * last 1.5 intervals. 383 */ 384 if (maybe_ip6f == NULL || 385 ip6f->ip6f_timer < maybe_ip6f->ip6f_timer || 386 (ip6f->ip6f_timer == maybe_ip6f->ip6f_timer && 387 ip6f->ip6f_last_uses + ip6f->ip6f_uses < 388 maybe_ip6f->ip6f_last_uses + 389 maybe_ip6f->ip6f_uses)) 390 maybe_ip6f = ip6f; 391 ip6f = LIST_NEXT(ip6f, ip6f_list); 392 } 393 ip6f = maybe_ip6f; 394 done: 395 /* 396 * Remove the entry from the flow table 397 */ 398 s = splnet(); 399 IP6FLOW_REMOVE(ip6f); 400 splx(s); 401 rtcache_free(&ip6f->ip6f_ro); 402 if (just_one) { 403 ip6flow_addstats(ip6f); 404 return ip6f; 405 } 406 ip6flow_inuse--; 407 ip6flow_addstats(ip6f); 408 pool_put(&ip6flow_pool, ip6f); 409 } 410 return NULL; 411} 412 413void 414ip6flow_slowtimo(void) 415{ 416 struct ip6flow *ip6f, *next_ip6f; 417 418 mutex_enter(softnet_lock); 419 KERNEL_LOCK(1, NULL); 420 421 for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) { 422 next_ip6f = LIST_NEXT(ip6f, ip6f_list); 423 if (PRT_SLOW_ISEXPIRED(ip6f->ip6f_timer) || 424 rtcache_validate(&ip6f->ip6f_ro) == NULL) { 425 ip6flow_free(ip6f); 426 } else { 427 ip6f->ip6f_last_uses = ip6f->ip6f_uses; 428 ip6flow_addstats(ip6f); 429 ip6f->ip6f_uses = 0; 430 ip6f->ip6f_dropped = 0; 431 ip6f->ip6f_forwarded = 0; 432 } 433 } 434 435 KERNEL_UNLOCK_ONE(NULL); 436 mutex_exit(softnet_lock); 437} 438 439/* 440 * We have successfully forwarded a packet using the normal 441 * IPv6 stack. Now create/update a flow. 442 */ 443void 444ip6flow_create(const struct route *ro, struct mbuf *m) 445{ 446 const struct ip6_hdr *ip6; 447 struct ip6flow *ip6f; 448 size_t hash; 449 int s; 450 451 ip6 = mtod(m, const struct ip6_hdr *); 452 453 /* 454 * If IPv6 Fast Forward is disabled, don't create a flow. 455 * It can be disabled by setting net.inet6.ip6.maxflows to 0. 456 * 457 * Don't create a flow for ICMPv6 messages. 458 */ 459 if (ip6_maxflows == 0 || ip6->ip6_nxt == IPPROTO_IPV6_ICMP) 460 return; 461 462 /* 463 * See if an existing flow exists. If so: 464 * - Remove the flow 465 * - Add flow statistics 466 * - Free the route 467 * - Reset statistics 468 * 469 * If a flow doesn't exist allocate a new one if 470 * ip6_maxflows hasn't reached its limit. If it has 471 * been reached, reap some flows. 472 */ 473 ip6f = ip6flow_lookup(ip6); 474 if (ip6f == NULL) { 475 if (ip6flow_inuse >= ip6_maxflows) { 476 ip6f = ip6flow_reap(1); 477 } else { 478 ip6f = pool_get(&ip6flow_pool, PR_NOWAIT); 479 if (ip6f == NULL) 480 return; 481 ip6flow_inuse++; 482 } 483 memset(ip6f, 0, sizeof(*ip6f)); 484 } else { 485 s = splnet(); 486 IP6FLOW_REMOVE(ip6f); 487 splx(s); 488 ip6flow_addstats(ip6f); 489 rtcache_free(&ip6f->ip6f_ro); 490 ip6f->ip6f_uses = 0; 491 ip6f->ip6f_last_uses = 0; 492 ip6f->ip6f_dropped = 0; 493 ip6f->ip6f_forwarded = 0; 494 } 495 496 /* 497 * Fill in the updated/new details. 498 */ 499 rtcache_copy(&ip6f->ip6f_ro, ro); 500 ip6f->ip6f_dst = ip6->ip6_dst; 501 ip6f->ip6f_src = ip6->ip6_src; 502 ip6f->ip6f_flow = ip6->ip6_flow; 503 PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER); 504 505 /* 506 * Insert into the approriate bucket of the flow table. 507 */ 508 hash = ip6flow_hash(ip6); 509 s = splnet(); 510 IP6FLOW_INSERT(&ip6flowtable[hash], ip6f); 511 splx(s); 512} 513 514/* 515 * Invalidate/remove all flows - if new_size is positive we 516 * resize the hash table. 517 */ 518int 519ip6flow_invalidate_all(int new_size) 520{ 521 struct ip6flow *ip6f, *next_ip6f; 522 int s, error; 523 524 error = 0; 525 s = splnet(); 526 for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) { 527 next_ip6f = LIST_NEXT(ip6f, ip6f_list); 528 ip6flow_free(ip6f); 529 } 530 531 if (new_size) 532 error = ip6flow_init(new_size); 533 splx(s); 534 535 return error; 536} 537