1 /*- 2 * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org> 3 * Copyright (c) 2001-2003 Roman V. Palagin <romanp@unshadow.net> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $SourceForge: netflow.c,v 1.41 2004/09/05 11:41:10 glebius Exp $ 28 */ 29 30 static const char rcs_id[] = 31 "@(#) $FreeBSD$"; 32 33 #include <sys/param.h> 34 #include <sys/kernel.h> 35 #include <sys/limits.h> 36 #include <sys/mbuf.h> 37 #include <sys/syslog.h> 38 #include <sys/systm.h> 39 #include <sys/socket.h> 40 41 #include <machine/atomic.h> 42 43 #include <net/if.h> 44 #include <net/route.h> 45 #include <netinet/in.h> 46 #include <netinet/in_systm.h> 47 #include <netinet/ip.h> 48 #include <netinet/tcp.h> 49 #include <netinet/udp.h> 50 51 #include <netgraph/ng_message.h> 52 #include <netgraph/netgraph.h> 53 54 #include <netgraph/netflow/netflow.h> 55 #include <netgraph/netflow/ng_netflow.h> 56 57 #define NBUCKETS (65536) /* must be power of 2 */ 58 59 /* This hash is for TCP or UDP packets. */ 60 #define FULL_HASH(addr1, addr2, port1, port2) \ 61 (((addr1 ^ (addr1 >> 16) ^ \ 62 htons(addr2 ^ (addr2 >> 16))) ^ \ 63 port1 ^ htons(port2)) & \ 64 (NBUCKETS - 1)) 65 66 /* This hash is for all other IP packets. */ 67 #define ADDR_HASH(addr1, addr2) \ 68 ((addr1 ^ (addr1 >> 16) ^ \ 69 htons(addr2 ^ (addr2 >> 16))) & \ 70 (NBUCKETS - 1)) 71 72 /* Macros to shorten logical constructions */ 73 /* XXX: priv must exist in namespace */ 74 #define INACTIVE(fle) (time_uptime - fle->f.last > priv->info.nfinfo_inact_t) 75 #define AGED(fle) (time_uptime - fle->f.first > priv->info.nfinfo_act_t) 76 #define ISFREE(fle) (fle->f.packets == 0) 77 78 /* 79 * 4 is a magical number: statistically number of 4-packet flows is 80 * bigger than 5,6,7...-packet flows by an order of magnitude. Most UDP/ICMP 81 * scans are 1 packet (~ 90% of flow cache). TCP scans are 2-packet in case 82 * of reachable host and 4-packet otherwise. 83 */ 84 #define SMALL(fle) (fle->f.packets <= 4) 85 86 /* 87 * Cisco uses milliseconds for uptime. Bad idea, since it overflows 88 * every 48+ days. But we will do same to keep compatibility. This macro 89 * does overflowable multiplication to 1000. 90 */ 91 #define MILLIUPTIME(t) (((t) << 9) + /* 512 */ \ 92 ((t) << 8) + /* 256 */ \ 93 ((t) << 7) + /* 128 */ \ 94 ((t) << 6) + /* 64 */ \ 95 ((t) << 5) + /* 32 */ \ 96 ((t) << 3)) /* 8 */ 97 98 MALLOC_DECLARE(M_NETFLOW_HASH); 99 MALLOC_DEFINE(M_NETFLOW_HASH, "netflow_hash", "NetFlow hash"); 100 101 static int export_add(item_p, struct flow_entry *); 102 static int export_send(priv_p, item_p, int flags); 103 104 /* Generate hash for a given flow record. */ 105 static __inline uint32_t 106 ip_hash(struct flow_rec *r) 107 { 108 switch (r->r_ip_p) { 109 case IPPROTO_TCP: 110 case IPPROTO_UDP: 111 return FULL_HASH(r->r_src.s_addr, r->r_dst.s_addr, 112 r->r_sport, r->r_dport); 113 default: 114 return ADDR_HASH(r->r_src.s_addr, r->r_dst.s_addr); 115 } 116 } 117 118 /* This is callback from uma(9), called on alloc. */ 119 static int 120 uma_ctor_flow(void *mem, int size, void *arg, int how) 121 { 122 priv_p priv = (priv_p )arg; 123 124 if (atomic_load_acq_32(&priv->info.nfinfo_used) >= CACHESIZE) 125 return (ENOMEM); 126 127 atomic_add_32(&priv->info.nfinfo_used, 1); 128 129 return (0); 130 } 131 132 /* This is callback from uma(9), called on free. */ 133 static void 134 uma_dtor_flow(void *mem, int size, void *arg) 135 { 136 priv_p priv = (priv_p )arg; 137 138 atomic_subtract_32(&priv->info.nfinfo_used, 1); 139 } 140 141 /* 142 * Detach export datagram from priv, if there is any. 143 * If there is no, allocate a new one. 144 */ 145 static item_p 146 get_export_dgram(priv_p priv) 147 { 148 item_p item = NULL; 149 150 mtx_lock(&priv->export_mtx); 151 if (priv->export_item != NULL) { 152 item = priv->export_item; 153 priv->export_item = NULL; 154 } 155 mtx_unlock(&priv->export_mtx); 156 157 if (item == NULL) { 158 struct netflow_v5_export_dgram *dgram; 159 struct mbuf *m; 160 161 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR); 162 if (m == NULL) 163 return (NULL); 164 item = ng_package_data(m, NG_NOFLAGS); 165 if (item == NULL) 166 return (NULL); 167 dgram = mtod(m, struct netflow_v5_export_dgram *); 168 dgram->header.count = 0; 169 dgram->header.version = htons(NETFLOW_V5); 170 171 } 172 173 return (item); 174 } 175 176 /* 177 * Re-attach incomplete datagram back to priv. 178 * If there is already another one, then send incomplete. */ 179 static void 180 return_export_dgram(priv_p priv, item_p item, int flags) 181 { 182 /* 183 * It may happen on SMP, that some thread has already 184 * put its item there, in this case we bail out and 185 * send what we have to collector. 186 */ 187 mtx_lock(&priv->export_mtx); 188 if (priv->export_item == NULL) { 189 priv->export_item = item; 190 mtx_unlock(&priv->export_mtx); 191 } else { 192 mtx_unlock(&priv->export_mtx); 193 export_send(priv, item, flags); 194 } 195 } 196 197 /* 198 * The flow is over. Call export_add() and free it. If datagram is 199 * full, then call export_send(). 200 */ 201 static __inline void 202 expire_flow(priv_p priv, item_p *item, struct flow_entry *fle, int flags) 203 { 204 if (*item == NULL) 205 *item = get_export_dgram(priv); 206 if (*item == NULL) { 207 atomic_add_32(&priv->info.nfinfo_export_failed, 1); 208 uma_zfree_arg(priv->zone, fle, priv); 209 return; 210 } 211 if (export_add(*item, fle) > 0) { 212 export_send(priv, *item, flags); 213 *item = NULL; 214 } 215 uma_zfree_arg(priv->zone, fle, priv); 216 } 217 218 /* Get a snapshot of node statistics */ 219 void 220 ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i) 221 { 222 /* XXX: atomic */ 223 memcpy((void *)i, (void *)&priv->info, sizeof(priv->info)); 224 } 225 226 /* 227 * Insert a record into defined slot. 228 * 229 * First we get for us a free flow entry, then fill in all 230 * possible fields in it. 231 * 232 * TODO: consider dropping hash mutex while filling in datagram, 233 * as this was done in previous version. Need to test & profile 234 * to be sure. 235 */ 236 static __inline int 237 hash_insert(priv_p priv, struct flow_hash_entry *hsh, struct flow_rec *r, 238 int plen, uint8_t tcp_flags) 239 { 240 struct flow_entry *fle; 241 struct sockaddr_in sin; 242 struct rtentry *rt; 243 244 mtx_assert(&hsh->mtx, MA_OWNED); 245 246 fle = uma_zalloc_arg(priv->zone, priv, M_NOWAIT); 247 if (fle == NULL) { 248 atomic_add_32(&priv->info.nfinfo_alloc_failed, 1); 249 return (ENOMEM); 250 } 251 252 /* 253 * Now fle is totally ours. It is detached from all lists, 254 * we can safely edit it. 255 */ 256 257 bcopy(r, &fle->f.r, sizeof(struct flow_rec)); 258 fle->f.bytes = plen; 259 fle->f.packets = 1; 260 fle->f.tcp_flags = tcp_flags; 261 262 fle->f.first = fle->f.last = time_uptime; 263 264 /* 265 * First we do route table lookup on destination address. So we can 266 * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases. 267 */ 268 bzero(&sin, sizeof(sin)); 269 sin.sin_len = sizeof(struct sockaddr_in); 270 sin.sin_family = AF_INET; 271 sin.sin_addr = fle->f.r.r_dst; 272 /* XXX MRT 0 as a default.. need the m here to get fib */ 273 rt = rtalloc1_fib((struct sockaddr *)&sin, 0, 0, 0); 274 if (rt != NULL) { 275 fle->f.fle_o_ifx = rt->rt_ifp->if_index; 276 277 if (rt->rt_flags & RTF_GATEWAY && 278 rt->rt_gateway->sa_family == AF_INET) 279 fle->f.next_hop = 280 ((struct sockaddr_in *)(rt->rt_gateway))->sin_addr; 281 282 if (rt_mask(rt)) 283 fle->f.dst_mask = bitcount32(((struct sockaddr_in *) 284 rt_mask(rt))->sin_addr.s_addr); 285 else if (rt->rt_flags & RTF_HOST) 286 /* Give up. We can't determine mask :( */ 287 fle->f.dst_mask = 32; 288 289 RTFREE_LOCKED(rt); 290 } 291 292 /* Do route lookup on source address, to fill in src_mask. */ 293 bzero(&sin, sizeof(sin)); 294 sin.sin_len = sizeof(struct sockaddr_in); 295 sin.sin_family = AF_INET; 296 sin.sin_addr = fle->f.r.r_src; 297 /* XXX MRT 0 as a default revisit. need the mbuf for fib*/ 298 rt = rtalloc1_fib((struct sockaddr *)&sin, 0, 0, 0); 299 if (rt != NULL) { 300 if (rt_mask(rt)) 301 fle->f.src_mask = bitcount32(((struct sockaddr_in *) 302 rt_mask(rt))->sin_addr.s_addr); 303 else if (rt->rt_flags & RTF_HOST) 304 /* Give up. We can't determine mask :( */ 305 fle->f.src_mask = 32; 306 307 RTFREE_LOCKED(rt); 308 } 309 310 /* Push new flow at the and of hash. */ 311 TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash); 312 313 return (0); 314 } 315 316 317 /* 318 * Non-static functions called from ng_netflow.c 319 */ 320 321 /* Allocate memory and set up flow cache */ 322 int 323 ng_netflow_cache_init(priv_p priv) 324 { 325 struct flow_hash_entry *hsh; 326 int i; 327 328 /* Initialize cache UMA zone. */ 329 priv->zone = uma_zcreate("NetFlow cache", sizeof(struct flow_entry), 330 uma_ctor_flow, uma_dtor_flow, NULL, NULL, UMA_ALIGN_CACHE, 0); 331 uma_zone_set_max(priv->zone, CACHESIZE); 332 333 /* Allocate hash. */ 334 priv->hash = malloc(NBUCKETS * sizeof(struct flow_hash_entry), 335 M_NETFLOW_HASH, M_WAITOK | M_ZERO); 336 337 if (priv->hash == NULL) { 338 uma_zdestroy(priv->zone); 339 return (ENOMEM); 340 } 341 342 /* Initialize hash. */ 343 for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) { 344 mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF); 345 TAILQ_INIT(&hsh->head); 346 } 347 348 mtx_init(&priv->export_mtx, "export dgram lock", NULL, MTX_DEF); 349 350 return (0); 351 } 352 353 /* Free all flow cache memory. Called from node close method. */ 354 void 355 ng_netflow_cache_flush(priv_p priv) 356 { 357 struct flow_entry *fle, *fle1; 358 struct flow_hash_entry *hsh; 359 item_p item = NULL; 360 int i; 361 362 /* 363 * We are going to free probably billable data. 364 * Expire everything before freeing it. 365 * No locking is required since callout is already drained. 366 */ 367 for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) 368 TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) { 369 TAILQ_REMOVE(&hsh->head, fle, fle_hash); 370 expire_flow(priv, &item, fle, NG_QUEUE); 371 } 372 373 if (item != NULL) 374 export_send(priv, item, NG_QUEUE); 375 376 uma_zdestroy(priv->zone); 377 378 /* Destroy hash mutexes. */ 379 for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) 380 mtx_destroy(&hsh->mtx); 381 382 /* Free hash memory. */ 383 if (priv->hash) 384 free(priv->hash, M_NETFLOW_HASH); 385 386 mtx_destroy(&priv->export_mtx); 387 } 388 389 /* Insert packet from into flow cache. */ 390 int 391 ng_netflow_flow_add(priv_p priv, struct ip *ip, unsigned int src_if_index) 392 { 393 register struct flow_entry *fle, *fle1; 394 struct flow_hash_entry *hsh; 395 struct flow_rec r; 396 item_p item = NULL; 397 int hlen, plen; 398 int error = 0; 399 uint8_t tcp_flags = 0; 400 401 /* Try to fill flow_rec r */ 402 bzero(&r, sizeof(r)); 403 /* check version */ 404 if (ip->ip_v != IPVERSION) 405 return (EINVAL); 406 407 /* verify min header length */ 408 hlen = ip->ip_hl << 2; 409 410 if (hlen < sizeof(struct ip)) 411 return (EINVAL); 412 413 r.r_src = ip->ip_src; 414 r.r_dst = ip->ip_dst; 415 416 /* save packet length */ 417 plen = ntohs(ip->ip_len); 418 419 r.r_ip_p = ip->ip_p; 420 r.r_tos = ip->ip_tos; 421 422 r.r_i_ifx = src_if_index; 423 424 /* 425 * XXX NOTE: only first fragment of fragmented TCP, UDP and 426 * ICMP packet will be recorded with proper s_port and d_port. 427 * Following fragments will be recorded simply as IP packet with 428 * ip_proto = ip->ip_p and s_port, d_port set to zero. 429 * I know, it looks like bug. But I don't want to re-implement 430 * ip packet assebmling here. Anyway, (in)famous trafd works this way - 431 * and nobody complains yet :) 432 */ 433 if ((ip->ip_off & htons(IP_OFFMASK)) == 0) 434 switch(r.r_ip_p) { 435 case IPPROTO_TCP: 436 { 437 register struct tcphdr *tcp; 438 439 tcp = (struct tcphdr *)((caddr_t )ip + hlen); 440 r.r_sport = tcp->th_sport; 441 r.r_dport = tcp->th_dport; 442 tcp_flags = tcp->th_flags; 443 break; 444 } 445 case IPPROTO_UDP: 446 r.r_ports = *(uint32_t *)((caddr_t )ip + hlen); 447 break; 448 } 449 450 /* Update node statistics. XXX: race... */ 451 priv->info.nfinfo_packets ++; 452 priv->info.nfinfo_bytes += plen; 453 454 /* Find hash slot. */ 455 hsh = &priv->hash[ip_hash(&r)]; 456 457 mtx_lock(&hsh->mtx); 458 459 /* 460 * Go through hash and find our entry. If we encounter an 461 * entry, that should be expired, purge it. We do a reverse 462 * search since most active entries are first, and most 463 * searches are done on most active entries. 464 */ 465 TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) { 466 if (bcmp(&r, &fle->f.r, sizeof(struct flow_rec)) == 0) 467 break; 468 if ((INACTIVE(fle) && SMALL(fle)) || AGED(fle)) { 469 TAILQ_REMOVE(&hsh->head, fle, fle_hash); 470 expire_flow(priv, &item, fle, NG_QUEUE); 471 atomic_add_32(&priv->info.nfinfo_act_exp, 1); 472 } 473 } 474 475 if (fle) { /* An existent entry. */ 476 477 fle->f.bytes += plen; 478 fle->f.packets ++; 479 fle->f.tcp_flags |= tcp_flags; 480 fle->f.last = time_uptime; 481 482 /* 483 * We have the following reasons to expire flow in active way: 484 * - it hit active timeout 485 * - a TCP connection closed 486 * - it is going to overflow counter 487 */ 488 if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle) || 489 (fle->f.bytes >= (UINT_MAX - IF_MAXMTU)) ) { 490 TAILQ_REMOVE(&hsh->head, fle, fle_hash); 491 expire_flow(priv, &item, fle, NG_QUEUE); 492 atomic_add_32(&priv->info.nfinfo_act_exp, 1); 493 } else { 494 /* 495 * It is the newest, move it to the tail, 496 * if it isn't there already. Next search will 497 * locate it quicker. 498 */ 499 if (fle != TAILQ_LAST(&hsh->head, fhead)) { 500 TAILQ_REMOVE(&hsh->head, fle, fle_hash); 501 TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash); 502 } 503 } 504 } else /* A new flow entry. */ 505 error = hash_insert(priv, hsh, &r, plen, tcp_flags); 506 507 mtx_unlock(&hsh->mtx); 508 509 if (item != NULL) 510 return_export_dgram(priv, item, NG_QUEUE); 511 512 return (error); 513 } 514 515 /* 516 * Return records from cache to userland. 517 * 518 * TODO: matching particular IP should be done in kernel, here. 519 */ 520 int 521 ng_netflow_flow_show(priv_p priv, uint32_t last, struct ng_mesg *resp) 522 { 523 struct flow_hash_entry *hsh; 524 struct flow_entry *fle; 525 struct ngnf_flows *data; 526 int i; 527 528 data = (struct ngnf_flows *)resp->data; 529 data->last = 0; 530 data->nentries = 0; 531 532 /* Check if this is a first run */ 533 if (last == 0) { 534 hsh = priv->hash; 535 i = 0; 536 } else { 537 if (last > NBUCKETS-1) 538 return (EINVAL); 539 hsh = priv->hash + last; 540 i = last; 541 } 542 543 /* 544 * We will transfer not more than NREC_AT_ONCE. More data 545 * will come in next message. 546 * We send current hash index to userland, and userland should 547 * return it back to us. Then, we will restart with new entry. 548 * 549 * The resulting cache snapshot is inaccurate for the 550 * following reasons: 551 * - we skip locked hash entries 552 * - we bail out, if someone wants our entry 553 * - we skip rest of entry, when hit NREC_AT_ONCE 554 */ 555 for (; i < NBUCKETS; hsh++, i++) { 556 if (mtx_trylock(&hsh->mtx) == 0) 557 continue; 558 559 TAILQ_FOREACH(fle, &hsh->head, fle_hash) { 560 if (hsh->mtx.mtx_lock & MTX_CONTESTED) 561 break; 562 563 bcopy(&fle->f, &(data->entries[data->nentries]), 564 sizeof(fle->f)); 565 data->nentries++; 566 if (data->nentries == NREC_AT_ONCE) { 567 mtx_unlock(&hsh->mtx); 568 if (++i < NBUCKETS) 569 data->last = i; 570 return (0); 571 } 572 } 573 mtx_unlock(&hsh->mtx); 574 } 575 576 return (0); 577 } 578 579 /* We have full datagram in privdata. Send it to export hook. */ 580 static int 581 export_send(priv_p priv, item_p item, int flags) 582 { 583 struct mbuf *m = NGI_M(item); 584 struct netflow_v5_export_dgram *dgram = mtod(m, 585 struct netflow_v5_export_dgram *); 586 struct netflow_v5_header *header = &dgram->header; 587 struct timespec ts; 588 int error = 0; 589 590 /* Fill mbuf header. */ 591 m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v5_record) * 592 header->count + sizeof(struct netflow_v5_header); 593 594 /* Fill export header. */ 595 header->sys_uptime = htonl(MILLIUPTIME(time_uptime)); 596 getnanotime(&ts); 597 header->unix_secs = htonl(ts.tv_sec); 598 header->unix_nsecs = htonl(ts.tv_nsec); 599 header->engine_type = 0; 600 header->engine_id = 0; 601 header->pad = 0; 602 header->flow_seq = htonl(atomic_fetchadd_32(&priv->flow_seq, 603 header->count)); 604 header->count = htons(header->count); 605 606 if (priv->export != NULL) 607 NG_FWD_ITEM_HOOK_FLAGS(error, item, priv->export, flags); 608 else 609 NG_FREE_ITEM(item); 610 611 return (error); 612 } 613 614 615 /* Add export record to dgram. */ 616 static int 617 export_add(item_p item, struct flow_entry *fle) 618 { 619 struct netflow_v5_export_dgram *dgram = mtod(NGI_M(item), 620 struct netflow_v5_export_dgram *); 621 struct netflow_v5_header *header = &dgram->header; 622 struct netflow_v5_record *rec; 623 624 rec = &dgram->r[header->count]; 625 header->count ++; 626 627 KASSERT(header->count <= NETFLOW_V5_MAX_RECORDS, 628 ("ng_netflow: export too big")); 629 630 /* Fill in export record. */ 631 rec->src_addr = fle->f.r.r_src.s_addr; 632 rec->dst_addr = fle->f.r.r_dst.s_addr; 633 rec->next_hop = fle->f.next_hop.s_addr; 634 rec->i_ifx = htons(fle->f.fle_i_ifx); 635 rec->o_ifx = htons(fle->f.fle_o_ifx); 636 rec->packets = htonl(fle->f.packets); 637 rec->octets = htonl(fle->f.bytes); 638 rec->first = htonl(MILLIUPTIME(fle->f.first)); 639 rec->last = htonl(MILLIUPTIME(fle->f.last)); 640 rec->s_port = fle->f.r.r_sport; 641 rec->d_port = fle->f.r.r_dport; 642 rec->flags = fle->f.tcp_flags; 643 rec->prot = fle->f.r.r_ip_p; 644 rec->tos = fle->f.r.r_tos; 645 rec->dst_mask = fle->f.dst_mask; 646 rec->src_mask = fle->f.src_mask; 647 648 /* Not supported fields. */ 649 rec->src_as = rec->dst_as = 0; 650 651 if (header->count == NETFLOW_V5_MAX_RECORDS) 652 return (1); /* end of datagram */ 653 else 654 return (0); 655 } 656 657 /* Periodic flow expiry run. */ 658 void 659 ng_netflow_expire(void *arg) 660 { 661 struct flow_entry *fle, *fle1; 662 struct flow_hash_entry *hsh; 663 priv_p priv = (priv_p )arg; 664 item_p item = NULL; 665 uint32_t used; 666 int i; 667 668 /* 669 * Going through all the cache. 670 */ 671 for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) { 672 /* 673 * Skip entries, that are already being worked on. 674 */ 675 if (mtx_trylock(&hsh->mtx) == 0) 676 continue; 677 678 used = atomic_load_acq_32(&priv->info.nfinfo_used); 679 TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) { 680 /* 681 * Interrupt thread wants this entry! 682 * Quick! Quick! Bail out! 683 */ 684 if (hsh->mtx.mtx_lock & MTX_CONTESTED) 685 break; 686 687 /* 688 * Don't expire aggressively while hash collision 689 * ratio is predicted small. 690 */ 691 if (used <= (NBUCKETS*2) && !INACTIVE(fle)) 692 break; 693 694 if ((INACTIVE(fle) && (SMALL(fle) || 695 (used > (NBUCKETS*2)))) || AGED(fle)) { 696 TAILQ_REMOVE(&hsh->head, fle, fle_hash); 697 expire_flow(priv, &item, fle, NG_NOFLAGS); 698 used--; 699 atomic_add_32(&priv->info.nfinfo_inact_exp, 1); 700 } 701 } 702 mtx_unlock(&hsh->mtx); 703 } 704 705 if (item != NULL) 706 return_export_dgram(priv, item, NG_NOFLAGS); 707 708 /* Schedule next expire. */ 709 callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire, 710 (void *)priv); 711 } 712