1 /*- 2 * Copyright (c) 1998 The NetBSD Foundation, Inc. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to The NetBSD Foundation 6 * by the 3am Software Foundry ("3am"). It was developed by Matt Thomas. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the NetBSD 19 * Foundation, Inc. and its contributors. 20 * 4. Neither the name of The NetBSD Foundation nor the names of its 21 * contributors may be used to endorse or promote products derived 22 * from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 26 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 27 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 28 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 * POSSIBILITY OF SUCH DAMAGE. 35 * 36 * $FreeBSD: src/sys/netinet/ip_flow.c,v 1.9.2.2 2001/11/04 17:35:31 luigi Exp $ 37 * $DragonFly: src/sys/netinet/ip_flow.c,v 1.13 2008/04/03 16:02:32 sephe Exp $ 38 */ 39 40 #include <sys/param.h> 41 #include <sys/kernel.h> 42 #include <sys/malloc.h> 43 #include <sys/mbuf.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/sysctl.h> 47 #include <sys/thread2.h> 48 49 #include <machine/smp.h> 50 51 #include <net/if.h> 52 #include <net/route.h> 53 #include <net/netisr.h> 54 #include <net/netmsg2.h> 55 56 #include <netinet/in.h> 57 #include <netinet/ip.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/ip_flow.h> 61 62 #define IPFLOW_TIMER (5 * PR_SLOWHZ) 63 #define IPFLOW_HASHBITS 6 /* should not be a multiple of 8 */ 64 #define IPFLOW_HASHSIZE (1 << IPFLOW_HASHBITS) 65 #define IPFLOW_MAX 256 66 67 #define IPFLOW_RTENTRY_ISDOWN(rt) \ 68 (((rt)->rt_flags & RTF_UP) == 0 || ((rt)->rt_ifp->if_flags & IFF_UP) == 0) 69 70 #define ipflow_inuse ipflow_inuse_pcpu[mycpuid] 71 #define ipflows ipflows_pcpu[mycpuid] 72 73 static LIST_HEAD(ipflowhead, ipflow) ipflows_pcpu[MAXCPU][IPFLOW_HASHSIZE]; 74 static int ipflow_inuse_pcpu[MAXCPU]; 75 static struct netmsg ipflow_timo_netmsgs[MAXCPU]; 76 static int ipflow_active = 0; 77 78 SYSCTL_NODE(_net_inet_ip, OID_AUTO, ipflow, CTLFLAG_RW, 0, "ip flow"); 79 SYSCTL_INT(_net_inet_ip, IPCTL_FASTFORWARDING, fastforwarding, CTLFLAG_RW, 80 &ipflow_active, 0, "Enable flow-based IP forwarding"); 81 82 static MALLOC_DEFINE(M_IPFLOW, "ip_flow", "IP flow"); 83 84 static unsigned 85 ipflow_hash(struct in_addr dst, struct in_addr src, unsigned tos) 86 { 87 unsigned hash = tos; 88 int idx; 89 90 for (idx = 0; idx < 32; idx += IPFLOW_HASHBITS) 91 hash += (dst.s_addr >> (32 - idx)) + (src.s_addr >> idx); 92 return hash & (IPFLOW_HASHSIZE-1); 93 } 94 95 static struct ipflow * 96 ipflow_lookup(const struct ip *ip) 97 { 98 unsigned hash; 99 struct ipflow *ipf; 100 101 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos); 102 103 crit_enter(); 104 ipf = LIST_FIRST(&ipflows[hash]); 105 while (ipf != NULL) { 106 if (ip->ip_dst.s_addr == ipf->ipf_dst.s_addr && 107 ip->ip_src.s_addr == ipf->ipf_src.s_addr && 108 ip->ip_tos == ipf->ipf_tos) 109 break; 110 ipf = LIST_NEXT(ipf, ipf_next); 111 } 112 crit_exit(); 113 114 return ipf; 115 } 116 117 int 118 ipflow_fastforward(struct mbuf *m, lwkt_serialize_t serializer) 119 { 120 struct ip *ip; 121 struct ipflow *ipf; 122 struct rtentry *rt; 123 struct sockaddr *dst; 124 struct ifnet *ifp; 125 int error; 126 127 /* 128 * Are we forwarding packets? Big enough for an IP packet? 129 */ 130 if (!ipforwarding || !ipflow_active || m->m_len < sizeof(struct ip)) 131 return 0; 132 133 /* 134 * IP header with no option and valid version and length 135 */ 136 ip = mtod(m, struct ip *); 137 if (ip->ip_v != IPVERSION || ip->ip_hl != (sizeof(struct ip) >> 2) || 138 ntohs(ip->ip_len) > m->m_pkthdr.len) 139 return 0; 140 141 /* 142 * Find a flow. 143 */ 144 ipf = ipflow_lookup(ip); 145 if (ipf == NULL) 146 return 0; 147 148 /* 149 * Route and interface still up? 150 */ 151 rt = ipf->ipf_ro.ro_rt; 152 if (IPFLOW_RTENTRY_ISDOWN(rt)) 153 return 0; 154 ifp = rt->rt_ifp; 155 156 /* 157 * Packet size OK? TTL? 158 */ 159 if (m->m_pkthdr.len > ifp->if_mtu || ip->ip_ttl <= IPTTLDEC) 160 return 0; 161 162 /* 163 * Everything checks out and so we can forward this packet. 164 * Modify the TTL and incrementally change the checksum. 165 */ 166 ip->ip_ttl -= IPTTLDEC; 167 if (ip->ip_sum >= htons(0xffff - (IPTTLDEC << 8))) 168 ip->ip_sum += htons(IPTTLDEC << 8) + 1; 169 else 170 ip->ip_sum += htons(IPTTLDEC << 8); 171 172 /* 173 * Send the packet on its way. All we can get back is ENOBUFS 174 */ 175 ipf->ipf_uses++; 176 ipf->ipf_timer = IPFLOW_TIMER; 177 178 if (rt->rt_flags & RTF_GATEWAY) 179 dst = rt->rt_gateway; 180 else 181 dst = &ipf->ipf_ro.ro_dst; 182 183 if (serializer) 184 lwkt_serialize_exit(serializer); 185 186 lwkt_serialize_enter(ifp->if_serializer); 187 error = ifp->if_output(ifp, m, dst, rt); 188 if (error) { 189 if (error == ENOBUFS) 190 ipf->ipf_dropped++; 191 else 192 ipf->ipf_errors++; 193 } 194 lwkt_serialize_exit(ifp->if_serializer); 195 196 if (serializer) 197 lwkt_serialize_enter(serializer); 198 return 1; 199 } 200 201 static void 202 ipflow_addstats(struct ipflow *ipf) 203 { 204 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses; 205 ipstat.ips_cantforward += ipf->ipf_errors + ipf->ipf_dropped; 206 ipstat.ips_forward += ipf->ipf_uses; 207 ipstat.ips_fastforward += ipf->ipf_uses; 208 } 209 210 static void 211 ipflow_free(struct ipflow *ipf) 212 { 213 /* 214 * Remove the flow from the hash table (at elevated IPL). 215 * Once it's off the list, we can deal with it at normal 216 * network IPL. 217 */ 218 crit_enter(); 219 LIST_REMOVE(ipf, ipf_next); 220 221 KKASSERT(ipflow_inuse > 0); 222 ipflow_inuse--; 223 crit_exit(); 224 225 ipflow_addstats(ipf); 226 RTFREE(ipf->ipf_ro.ro_rt); 227 kfree(ipf, M_IPFLOW); 228 } 229 230 static struct ipflow * 231 ipflow_reap(void) 232 { 233 struct ipflow *ipf, *maybe_ipf = NULL; 234 int idx; 235 236 crit_enter(); 237 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) { 238 ipf = LIST_FIRST(&ipflows[idx]); 239 while (ipf != NULL) { 240 /* 241 * If this no longer points to a valid route 242 * reclaim it. 243 */ 244 if ((ipf->ipf_ro.ro_rt->rt_flags & RTF_UP) == 0) 245 goto done; 246 247 /* 248 * choose the one that's been least recently used 249 * or has had the least uses in the last 1.5 250 * intervals. 251 */ 252 if (maybe_ipf == NULL || 253 ipf->ipf_timer < maybe_ipf->ipf_timer || 254 (ipf->ipf_timer == maybe_ipf->ipf_timer && 255 ipf->ipf_last_uses + ipf->ipf_uses < 256 maybe_ipf->ipf_last_uses + maybe_ipf->ipf_uses)) 257 maybe_ipf = ipf; 258 ipf = LIST_NEXT(ipf, ipf_next); 259 } 260 } 261 ipf = maybe_ipf; 262 done: 263 /* 264 * Remove the entry from the flow table. 265 */ 266 LIST_REMOVE(ipf, ipf_next); 267 crit_exit(); 268 269 ipflow_addstats(ipf); 270 RTFREE(ipf->ipf_ro.ro_rt); 271 return ipf; 272 } 273 274 static void 275 ipflow_timo_dispatch(struct netmsg *nmsg) 276 { 277 struct ipflow *ipf; 278 int idx; 279 280 crit_enter(); 281 lwkt_replymsg(&nmsg->nm_lmsg, 0); /* reply ASAP */ 282 283 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) { 284 ipf = LIST_FIRST(&ipflows[idx]); 285 while (ipf != NULL) { 286 struct ipflow *next_ipf = LIST_NEXT(ipf, ipf_next); 287 288 if (--ipf->ipf_timer == 0) { 289 ipflow_free(ipf); 290 } else { 291 ipf->ipf_last_uses = ipf->ipf_uses; 292 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses; 293 ipstat.ips_forward += ipf->ipf_uses; 294 ipstat.ips_fastforward += ipf->ipf_uses; 295 ipf->ipf_uses = 0; 296 } 297 ipf = next_ipf; 298 } 299 } 300 crit_exit(); 301 } 302 303 static void 304 ipflow_timo_ipi(void *arg __unused) 305 { 306 struct lwkt_msg *msg = &ipflow_timo_netmsgs[mycpuid].nm_lmsg; 307 308 crit_enter(); 309 if (msg->ms_flags & MSGF_DONE) 310 lwkt_sendmsg(cpu_portfn(mycpuid), msg); 311 crit_exit(); 312 } 313 314 void 315 ipflow_slowtimo(void) 316 { 317 #ifdef SMP 318 lwkt_send_ipiq_mask(smp_active_mask, ipflow_timo_ipi, NULL); 319 #else 320 ipflow_timo_ipi(NULL); 321 #endif 322 } 323 324 static void 325 ipflow_create_oncpu(const struct route *ro, struct mbuf *m) 326 { 327 const struct ip *const ip = mtod(m, struct ip *); 328 struct ipflow *ipf; 329 unsigned hash; 330 331 /* 332 * See if an existing flow struct exists. If so remove it from it's 333 * list and free the old route. If not, try to malloc a new one 334 * (if we aren't at our limit). 335 */ 336 ipf = ipflow_lookup(ip); 337 if (ipf == NULL) { 338 if (ipflow_inuse == IPFLOW_MAX) { 339 ipf = ipflow_reap(); 340 } else { 341 ipf = kmalloc(sizeof(*ipf), M_IPFLOW, 342 M_INTWAIT | M_NULLOK); 343 if (ipf == NULL) 344 return; 345 ipflow_inuse++; 346 } 347 bzero(ipf, sizeof(*ipf)); 348 } else if (IPFLOW_RTENTRY_ISDOWN(ipf->ipf_ro.ro_rt)) { 349 crit_enter(); 350 LIST_REMOVE(ipf, ipf_next); 351 crit_exit(); 352 353 ipflow_addstats(ipf); 354 RTFREE(ipf->ipf_ro.ro_rt); 355 ipf->ipf_uses = ipf->ipf_last_uses = 0; 356 ipf->ipf_errors = ipf->ipf_dropped = 0; 357 } else { 358 /* 359 * The route entry cached in ipf is still up, 360 * this could happen while the ipf installation 361 * is in transition state. 362 * XXX should not happen on UP box 363 */ 364 return; 365 } 366 367 /* 368 * Fill in the updated information. 369 */ 370 ipf->ipf_ro = *ro; 371 ro->ro_rt->rt_refcnt++; 372 ipf->ipf_dst = ip->ip_dst; 373 ipf->ipf_src = ip->ip_src; 374 ipf->ipf_tos = ip->ip_tos; 375 ipf->ipf_timer = IPFLOW_TIMER; 376 377 /* 378 * Insert into the approriate bucket of the flow table. 379 */ 380 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos); 381 crit_enter(); 382 LIST_INSERT_HEAD(&ipflows[hash], ipf, ipf_next); 383 crit_exit(); 384 } 385 386 #ifdef SMP 387 388 static void 389 ipflow_create_dispatch(struct netmsg *nmsg) 390 { 391 struct netmsg_packet *nmp = (struct netmsg_packet *)nmsg; 392 struct sockaddr_in *sin; 393 struct route ro; 394 int nextcpu; 395 396 bzero(&ro, sizeof(ro)); 397 sin = (struct sockaddr_in *)&ro.ro_dst; 398 sin->sin_family = AF_INET; 399 sin->sin_len = sizeof(struct sockaddr_in); 400 sin->sin_addr.s_addr = (in_addr_t)nmsg->nm_lmsg.u.ms_result32; 401 402 rtalloc_ign(&ro, RTF_PRCLONING); 403 if (ro.ro_rt != NULL) { 404 ipflow_create_oncpu(&ro, nmp->nm_packet); 405 RTFREE(ro.ro_rt); 406 } 407 408 nextcpu = mycpuid + 1; 409 if (nextcpu < ncpus) 410 lwkt_forwardmsg(cpu_portfn(nextcpu), &nmsg->nm_lmsg); 411 else 412 m_freem(nmp->nm_packet); 413 } 414 415 #endif /* SMP */ 416 417 void 418 ipflow_create(const struct route *ro, struct mbuf *m) 419 { 420 const struct ip *const ip = mtod(m, struct ip *); 421 #ifdef SMP 422 struct netmsg_packet *nmp; 423 struct netmsg *nmsg; 424 int nextcpu; 425 #endif 426 427 /* 428 * Don't create cache entries for ICMP messages. 429 */ 430 if (!ipflow_active || ip->ip_p == IPPROTO_ICMP) { 431 m_freem(m); 432 return; 433 } 434 435 #ifdef SMP 436 nmp = &m->m_hdr.mh_netmsg; 437 nmsg = &nmp->nm_netmsg; 438 439 netmsg_init(nmsg, &netisr_apanic_rport, 0, ipflow_create_dispatch); 440 nmp->nm_packet = m; 441 nmsg->nm_lmsg.u.ms_result32 = 442 ((const struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr; 443 444 if (mycpuid == 0) { 445 ipflow_create_oncpu(ro, m); 446 nextcpu = 1; 447 } else { 448 nextcpu = 0; 449 } 450 if (nextcpu < ncpus) 451 lwkt_sendmsg(cpu_portfn(nextcpu), &nmsg->nm_lmsg); 452 else 453 m_freem(m); 454 #else 455 ipflow_create_oncpu(ro, m); 456 m_freem(m); 457 #endif 458 } 459 460 static void 461 ipflow_init(void) 462 { 463 char oid_name[32]; 464 int i; 465 466 for (i = 0; i < ncpus; ++i) { 467 netmsg_init(&ipflow_timo_netmsgs[i], &netisr_adone_rport, 0, 468 ipflow_timo_dispatch); 469 470 ksnprintf(oid_name, sizeof(oid_name), "inuse%d", i); 471 472 SYSCTL_ADD_INT(NULL, 473 SYSCTL_STATIC_CHILDREN(_net_inet_ip_ipflow), 474 OID_AUTO, oid_name, CTLFLAG_RD, &ipflow_inuse_pcpu[i], 0, 475 "# of ip flow being used"); 476 } 477 } 478 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipflow_init, 0); 479