ip_flow.c revision 1.55.2.1
1 /* $NetBSD: ip_flow.c,v 1.55.2.1 2008/05/16 02:25:41 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 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 Matt Thomas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: ip_flow.c,v 1.55.2.1 2008/05/16 02:25:41 yamt Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/malloc.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/kernel.h> 46 #include <sys/pool.h> 47 #include <sys/sysctl.h> 48 49 #include <net/if.h> 50 #include <net/if_dl.h> 51 #include <net/route.h> 52 #include <net/pfil.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_systm.h> 56 #include <netinet/ip.h> 57 #include <netinet/in_pcb.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/ip_private.h> 61 62 /* 63 * Similar code is very well commented in netinet6/ip6_flow.c 64 */ 65 66 struct ipflow { 67 LIST_ENTRY(ipflow) ipf_list; /* next in active list */ 68 LIST_ENTRY(ipflow) ipf_hash; /* next ipflow in bucket */ 69 struct in_addr ipf_dst; /* destination address */ 70 struct in_addr ipf_src; /* source address */ 71 uint8_t ipf_tos; /* type-of-service */ 72 struct route ipf_ro; /* associated route entry */ 73 u_long ipf_uses; /* number of uses in this period */ 74 u_long ipf_last_uses; /* number of uses in last period */ 75 u_long ipf_dropped; /* ENOBUFS retured by if_output */ 76 u_long ipf_errors; /* other errors returned by if_output */ 77 u_int ipf_timer; /* lifetime timer */ 78 time_t ipf_start; /* creation time */ 79 }; 80 81 #define IPFLOW_HASHBITS 6 /* should not be a multiple of 8 */ 82 83 POOL_INIT(ipflow_pool, sizeof(struct ipflow), 0, 0, 0, "ipflowpl", NULL, 84 IPL_NET); 85 86 LIST_HEAD(ipflowhead, ipflow); 87 88 #define IPFLOW_TIMER (5 * PR_SLOWHZ) 89 #define IPFLOW_DEFAULT_HASHSIZE (1 << IPFLOW_HASHBITS) 90 91 static struct ipflowhead *ipflowtable = NULL; 92 static struct ipflowhead ipflowlist; 93 static int ipflow_inuse; 94 95 #define IPFLOW_INSERT(bucket, ipf) \ 96 do { \ 97 LIST_INSERT_HEAD((bucket), (ipf), ipf_hash); \ 98 LIST_INSERT_HEAD(&ipflowlist, (ipf), ipf_list); \ 99 } while (/*CONSTCOND*/ 0) 100 101 #define IPFLOW_REMOVE(ipf) \ 102 do { \ 103 LIST_REMOVE((ipf), ipf_hash); \ 104 LIST_REMOVE((ipf), ipf_list); \ 105 } while (/*CONSTCOND*/ 0) 106 107 #ifndef IPFLOW_MAX 108 #define IPFLOW_MAX 256 109 #endif 110 int ip_maxflows = IPFLOW_MAX; 111 int ip_hashsize = IPFLOW_DEFAULT_HASHSIZE; 112 113 static size_t 114 ipflow_hash(const struct ip *ip) 115 { 116 size_t hash = ip->ip_tos; 117 size_t idx; 118 119 for (idx = 0; idx < 32; idx += IPFLOW_HASHBITS) { 120 hash += (ip->ip_dst.s_addr >> (32 - idx)) + 121 (ip->ip_src.s_addr >> idx); 122 } 123 124 return hash & (ip_hashsize-1); 125 } 126 127 static struct ipflow * 128 ipflow_lookup(const struct ip *ip) 129 { 130 size_t hash; 131 struct ipflow *ipf; 132 133 hash = ipflow_hash(ip); 134 135 LIST_FOREACH(ipf, &ipflowtable[hash], ipf_hash) { 136 if (ip->ip_dst.s_addr == ipf->ipf_dst.s_addr 137 && ip->ip_src.s_addr == ipf->ipf_src.s_addr 138 && ip->ip_tos == ipf->ipf_tos) 139 break; 140 } 141 return ipf; 142 } 143 144 int 145 ipflow_init(int table_size) 146 { 147 struct ipflowhead *new_table; 148 size_t i; 149 150 new_table = (struct ipflowhead *)malloc(sizeof(struct ipflowhead) * 151 table_size, M_RTABLE, M_NOWAIT); 152 153 if (new_table == NULL) 154 return 1; 155 156 if (ipflowtable != NULL) 157 free(ipflowtable, M_RTABLE); 158 159 ipflowtable = new_table; 160 ip_hashsize = table_size; 161 162 LIST_INIT(&ipflowlist); 163 for (i = 0; i < ip_hashsize; i++) 164 LIST_INIT(&ipflowtable[i]); 165 166 return 0; 167 } 168 169 int 170 ipflow_fastforward(struct mbuf *m) 171 { 172 struct ip *ip; 173 struct ip ip_store; 174 struct ipflow *ipf; 175 struct rtentry *rt; 176 const struct sockaddr *dst; 177 int error; 178 int iplen; 179 180 /* 181 * Are we forwarding packets? Big enough for an IP packet? 182 */ 183 if (!ipforwarding || ipflow_inuse == 0 || m->m_len < sizeof(struct ip)) 184 return 0; 185 186 /* 187 * Was packet received as a link-level multicast or broadcast? 188 * If so, don't try to fast forward.. 189 */ 190 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0) 191 return 0; 192 193 /* 194 * IP header with no option and valid version and length 195 */ 196 if (IP_HDR_ALIGNED_P(mtod(m, const void *))) 197 ip = mtod(m, struct ip *); 198 else { 199 memcpy(&ip_store, mtod(m, const void *), sizeof(ip_store)); 200 ip = &ip_store; 201 } 202 iplen = ntohs(ip->ip_len); 203 if (ip->ip_v != IPVERSION || ip->ip_hl != (sizeof(struct ip) >> 2) || 204 iplen < sizeof(struct ip) || iplen > m->m_pkthdr.len) 205 return 0; 206 /* 207 * Find a flow. 208 */ 209 if ((ipf = ipflow_lookup(ip)) == NULL) 210 return 0; 211 212 /* 213 * Verify the IP header checksum. 214 */ 215 switch (m->m_pkthdr.csum_flags & 216 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 217 M_CSUM_IPv4_BAD)) { 218 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 219 return (0); 220 221 case M_CSUM_IPv4: 222 /* Checksum was okay. */ 223 break; 224 225 default: 226 /* Must compute it ourselves. */ 227 if (in_cksum(m, sizeof(struct ip)) != 0) 228 return (0); 229 break; 230 } 231 232 /* 233 * Route and interface still up? 234 */ 235 if ((rt = rtcache_validate(&ipf->ipf_ro)) == NULL || 236 (rt->rt_ifp->if_flags & IFF_UP) == 0) 237 return 0; 238 239 /* 240 * Packet size OK? TTL? 241 */ 242 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu || ip->ip_ttl <= IPTTLDEC) 243 return 0; 244 245 /* 246 * Clear any in-bound checksum flags for this packet. 247 */ 248 m->m_pkthdr.csum_flags = 0; 249 250 /* 251 * Everything checks out and so we can forward this packet. 252 * Modify the TTL and incrementally change the checksum. 253 * 254 * This method of adding the checksum works on either endian CPU. 255 * If htons() is inlined, all the arithmetic is folded; otherwise 256 * the htons()s are combined by CSE due to the const attribute. 257 * 258 * Don't bother using HW checksumming here -- the incremental 259 * update is pretty fast. 260 */ 261 ip->ip_ttl -= IPTTLDEC; 262 if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 263 ip->ip_sum -= ~htons(IPTTLDEC << 8); 264 else 265 ip->ip_sum += htons(IPTTLDEC << 8); 266 267 /* 268 * Done modifying the header; copy it back, if necessary. 269 * 270 * XXX Use m_copyback_cow(9) here? --dyoung 271 */ 272 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) 273 memcpy(mtod(m, void *), &ip_store, sizeof(ip_store)); 274 275 /* 276 * Trim the packet in case it's too long.. 277 */ 278 if (m->m_pkthdr.len > iplen) { 279 if (m->m_len == m->m_pkthdr.len) { 280 m->m_len = iplen; 281 m->m_pkthdr.len = iplen; 282 } else 283 m_adj(m, iplen - m->m_pkthdr.len); 284 } 285 286 /* 287 * Send the packet on it's way. All we can get back is ENOBUFS 288 */ 289 ipf->ipf_uses++; 290 PRT_SLOW_ARM(ipf->ipf_timer, IPFLOW_TIMER); 291 292 if (rt->rt_flags & RTF_GATEWAY) 293 dst = rt->rt_gateway; 294 else 295 dst = rtcache_getdst(&ipf->ipf_ro); 296 297 if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) { 298 if (error == ENOBUFS) 299 ipf->ipf_dropped++; 300 else 301 ipf->ipf_errors++; 302 } 303 return 1; 304 } 305 306 static void 308 ipflow_addstats(struct ipflow *ipf) 309 { 310 struct rtentry *rt; 311 uint64_t *ips; 312 313 if ((rt = rtcache_validate(&ipf->ipf_ro)) != NULL) 314 rt->rt_use += ipf->ipf_uses; 315 316 ips = IP_STAT_GETREF(); 317 ips[IP_STAT_CANTFORWARD] += ipf->ipf_errors + ipf->ipf_dropped; 318 ips[IP_STAT_TOTAL] += ipf->ipf_uses; 319 ips[IP_STAT_FORWARD] += ipf->ipf_uses; 320 ips[IP_STAT_FASTFORWARD] += ipf->ipf_uses; 321 IP_STAT_PUTREF(); 322 } 323 324 static void 325 ipflow_free(struct ipflow *ipf) 326 { 327 int s; 328 /* 329 * Remove the flow from the hash table (at elevated IPL). 330 * Once it's off the list, we can deal with it at normal 331 * network IPL. 332 */ 333 s = splnet(); 334 IPFLOW_REMOVE(ipf); 335 splx(s); 336 ipflow_addstats(ipf); 337 rtcache_free(&ipf->ipf_ro); 338 ipflow_inuse--; 339 s = splnet(); 340 pool_put(&ipflow_pool, ipf); 341 splx(s); 342 } 343 344 static struct ipflow * 345 ipflow_reap(bool just_one) 346 { 347 while (just_one || ipflow_inuse > ip_maxflows) { 348 struct ipflow *ipf, *maybe_ipf = NULL; 349 int s; 350 351 ipf = LIST_FIRST(&ipflowlist); 352 while (ipf != NULL) { 353 /* 354 * If this no longer points to a valid route 355 * reclaim it. 356 */ 357 if (rtcache_validate(&ipf->ipf_ro) == NULL) 358 goto done; 359 /* 360 * choose the one that's been least recently 361 * used or has had the least uses in the 362 * last 1.5 intervals. 363 */ 364 if (maybe_ipf == NULL || 365 ipf->ipf_timer < maybe_ipf->ipf_timer || 366 (ipf->ipf_timer == maybe_ipf->ipf_timer && 367 ipf->ipf_last_uses + ipf->ipf_uses < 368 maybe_ipf->ipf_last_uses + 369 maybe_ipf->ipf_uses)) 370 maybe_ipf = ipf; 371 ipf = LIST_NEXT(ipf, ipf_list); 372 } 373 ipf = maybe_ipf; 374 done: 375 /* 376 * Remove the entry from the flow table. 377 */ 378 s = splnet(); 379 IPFLOW_REMOVE(ipf); 380 splx(s); 381 ipflow_addstats(ipf); 382 rtcache_free(&ipf->ipf_ro); 383 if (just_one) 384 return ipf; 385 pool_put(&ipflow_pool, ipf); 386 ipflow_inuse--; 387 } 388 return NULL; 389 } 390 391 void 392 ipflow_prune(void) 393 { 394 395 (void) ipflow_reap(false); 396 } 397 398 void 399 ipflow_slowtimo(void) 400 { 401 struct rtentry *rt; 402 struct ipflow *ipf, *next_ipf; 403 uint64_t *ips; 404 405 mutex_enter(softnet_lock); 406 KERNEL_LOCK(1, NULL); 407 for (ipf = LIST_FIRST(&ipflowlist); ipf != NULL; ipf = next_ipf) { 408 next_ipf = LIST_NEXT(ipf, ipf_list); 409 if (PRT_SLOW_ISEXPIRED(ipf->ipf_timer) || 410 (rt = rtcache_validate(&ipf->ipf_ro)) == NULL) { 411 ipflow_free(ipf); 412 } else { 413 ipf->ipf_last_uses = ipf->ipf_uses; 414 rt->rt_use += ipf->ipf_uses; 415 ips = IP_STAT_GETREF(); 416 ips[IP_STAT_TOTAL] += ipf->ipf_uses; 417 ips[IP_STAT_FORWARD] += ipf->ipf_uses; 418 ips[IP_STAT_FASTFORWARD] += ipf->ipf_uses; 419 IP_STAT_PUTREF(); 420 ipf->ipf_uses = 0; 421 } 422 } 423 KERNEL_UNLOCK_ONE(NULL); 424 mutex_exit(softnet_lock); 425 } 426 427 void 428 ipflow_create(const struct route *ro, struct mbuf *m) 429 { 430 const struct ip *const ip = mtod(m, const struct ip *); 431 struct ipflow *ipf; 432 size_t hash; 433 int s; 434 435 /* 436 * Don't create cache entries for ICMP messages. 437 */ 438 if (ip_maxflows == 0 || ip->ip_p == IPPROTO_ICMP) 439 return; 440 /* 441 * See if an existing flow struct exists. If so remove it from it's 442 * list and free the old route. If not, try to malloc a new one 443 * (if we aren't at our limit). 444 */ 445 ipf = ipflow_lookup(ip); 446 if (ipf == NULL) { 447 if (ipflow_inuse >= ip_maxflows) { 448 ipf = ipflow_reap(true); 449 } else { 450 s = splnet(); 451 ipf = pool_get(&ipflow_pool, PR_NOWAIT); 452 splx(s); 453 if (ipf == NULL) 454 return; 455 ipflow_inuse++; 456 } 457 memset(ipf, 0, sizeof(*ipf)); 458 } else { 459 s = splnet(); 460 IPFLOW_REMOVE(ipf); 461 splx(s); 462 ipflow_addstats(ipf); 463 rtcache_free(&ipf->ipf_ro); 464 ipf->ipf_uses = ipf->ipf_last_uses = 0; 465 ipf->ipf_errors = ipf->ipf_dropped = 0; 466 } 467 468 /* 469 * Fill in the updated information. 470 */ 471 rtcache_copy(&ipf->ipf_ro, ro); 472 ipf->ipf_dst = ip->ip_dst; 473 ipf->ipf_src = ip->ip_src; 474 ipf->ipf_tos = ip->ip_tos; 475 PRT_SLOW_ARM(ipf->ipf_timer, IPFLOW_TIMER); 476 ipf->ipf_start = time_uptime; 477 /* 478 * Insert into the approriate bucket of the flow table. 479 */ 480 hash = ipflow_hash(ip); 481 s = splnet(); 482 IPFLOW_INSERT(&ipflowtable[hash], ipf); 483 splx(s); 484 } 485 486 int 487 ipflow_invalidate_all(int new_size) 488 { 489 struct ipflow *ipf, *next_ipf; 490 int s, error; 491 492 error = 0; 493 s = splnet(); 494 for (ipf = LIST_FIRST(&ipflowlist); ipf != NULL; ipf = next_ipf) { 495 next_ipf = LIST_NEXT(ipf, ipf_list); 496 ipflow_free(ipf); 497 } 498 499 if (new_size) 500 error = ipflow_init(new_size); 501 splx(s); 502 503 return error; 504 } 505
Indexes created Wed Oct 15 03:09:54 GMT 2025