xref: /freebsd/sys/netgraph/netflow/netflow.c (revision 640235e2c2ba32947f7c59d168437ffa1280f1e6)
1 /*-
2  * Copyright (c) 2010-2011 Alexander V. Chernikov <melifaro@ipfw.ru>
3  * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
4  * Copyright (c) 2001-2003 Roman V. Palagin <romanp@unshadow.net>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $SourceForge: netflow.c,v 1.41 2004/09/05 11:41:10 glebius Exp $
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_inet6.h"
35 #include "opt_route.h"
36 #include <sys/param.h>
37 #include <sys/bitstring.h>
38 #include <sys/systm.h>
39 #include <sys/counter.h>
40 #include <sys/kernel.h>
41 #include <sys/ktr.h>
42 #include <sys/limits.h>
43 #include <sys/mbuf.h>
44 #include <sys/syslog.h>
45 #include <sys/socket.h>
46 #include <vm/uma.h>
47 
48 #include <net/if.h>
49 #include <net/if_dl.h>
50 #include <net/if_var.h>
51 #include <net/route.h>
52 #include <net/ethernet.h>
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip6.h>
57 #include <netinet/tcp.h>
58 #include <netinet/udp.h>
59 
60 #include <netgraph/ng_message.h>
61 #include <netgraph/netgraph.h>
62 
63 #include <netgraph/netflow/netflow.h>
64 #include <netgraph/netflow/netflow_v9.h>
65 #include <netgraph/netflow/ng_netflow.h>
66 
67 #define	NBUCKETS	(65536)		/* must be power of 2 */
68 
69 /* This hash is for TCP or UDP packets. */
70 #define FULL_HASH(addr1, addr2, port1, port2)	\
71 	(((addr1 ^ (addr1 >> 16) ^ 		\
72 	htons(addr2 ^ (addr2 >> 16))) ^ 	\
73 	port1 ^ htons(port2)) &			\
74 	(NBUCKETS - 1))
75 
76 /* This hash is for all other IP packets. */
77 #define ADDR_HASH(addr1, addr2)			\
78 	((addr1 ^ (addr1 >> 16) ^ 		\
79 	htons(addr2 ^ (addr2 >> 16))) &		\
80 	(NBUCKETS - 1))
81 
82 /* Macros to shorten logical constructions */
83 /* XXX: priv must exist in namespace */
84 #define	INACTIVE(fle)	(time_uptime - fle->f.last > priv->nfinfo_inact_t)
85 #define	AGED(fle)	(time_uptime - fle->f.first > priv->nfinfo_act_t)
86 #define	ISFREE(fle)	(fle->f.packets == 0)
87 
88 /*
89  * 4 is a magical number: statistically number of 4-packet flows is
90  * bigger than 5,6,7...-packet flows by an order of magnitude. Most UDP/ICMP
91  * scans are 1 packet (~ 90% of flow cache). TCP scans are 2-packet in case
92  * of reachable host and 4-packet otherwise.
93  */
94 #define	SMALL(fle)	(fle->f.packets <= 4)
95 
96 MALLOC_DEFINE(M_NETFLOW_HASH, "netflow_hash", "NetFlow hash");
97 
98 static int export_add(item_p, struct flow_entry *);
99 static int export_send(priv_p, fib_export_p, item_p, int);
100 
101 static int hash_insert(priv_p, struct flow_hash_entry *, struct flow_rec *,
102     int, uint8_t, uint8_t);
103 #ifdef INET6
104 static int hash6_insert(priv_p, struct flow_hash_entry *, struct flow6_rec *,
105     int, uint8_t, uint8_t);
106 #endif
107 
108 static void expire_flow(priv_p, fib_export_p, struct flow_entry *, int);
109 
110 /*
111  * Generate hash for a given flow record.
112  *
113  * FIB is not used here, because:
114  * most VRFS will carry public IPv4 addresses which are unique even
115  * without FIB private addresses can overlap, but this is worked out
116  * via flow_rec bcmp() containing fib id. In IPv6 world addresses are
117  * all globally unique (it's not fully true, there is FC00::/7 for example,
118  * but chances of address overlap are MUCH smaller)
119  */
120 static inline uint32_t
121 ip_hash(struct flow_rec *r)
122 {
123 
124 	switch (r->r_ip_p) {
125 	case IPPROTO_TCP:
126 	case IPPROTO_UDP:
127 		return FULL_HASH(r->r_src.s_addr, r->r_dst.s_addr,
128 		    r->r_sport, r->r_dport);
129 	default:
130 		return ADDR_HASH(r->r_src.s_addr, r->r_dst.s_addr);
131 	}
132 }
133 
134 #ifdef INET6
135 /* Generate hash for a given flow6 record. Use lower 4 octets from v6 addresses */
136 static inline uint32_t
137 ip6_hash(struct flow6_rec *r)
138 {
139 
140 	switch (r->r_ip_p) {
141 	case IPPROTO_TCP:
142 	case IPPROTO_UDP:
143 		return FULL_HASH(r->src.r_src6.__u6_addr.__u6_addr32[3],
144 		    r->dst.r_dst6.__u6_addr.__u6_addr32[3], r->r_sport,
145 		    r->r_dport);
146 	default:
147 		return ADDR_HASH(r->src.r_src6.__u6_addr.__u6_addr32[3],
148 		    r->dst.r_dst6.__u6_addr.__u6_addr32[3]);
149  	}
150 }
151 
152 static inline int
153 ip6_masklen(struct in6_addr *saddr, struct rt_addrinfo *info)
154 {
155 	const int nbits = sizeof(*saddr) * NBBY;
156 	int mlen;
157 
158 	if (info->rti_addrs & RTA_NETMASK)
159 		bit_count((bitstr_t *)saddr, 0, nbits, &mlen);
160 	else
161 		mlen = nbits;
162 	return (mlen);
163 }
164 #endif
165 
166 /*
167  * Detach export datagram from priv, if there is any.
168  * If there is no, allocate a new one.
169  */
170 static item_p
171 get_export_dgram(priv_p priv, fib_export_p fe)
172 {
173 	item_p	item = NULL;
174 
175 	mtx_lock(&fe->export_mtx);
176 	if (fe->exp.item != NULL) {
177 		item = fe->exp.item;
178 		fe->exp.item = NULL;
179 	}
180 	mtx_unlock(&fe->export_mtx);
181 
182 	if (item == NULL) {
183 		struct netflow_v5_export_dgram *dgram;
184 		struct mbuf *m;
185 
186 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
187 		if (m == NULL)
188 			return (NULL);
189 		item = ng_package_data(m, NG_NOFLAGS);
190 		if (item == NULL)
191 			return (NULL);
192 		dgram = mtod(m, struct netflow_v5_export_dgram *);
193 		dgram->header.count = 0;
194 		dgram->header.version = htons(NETFLOW_V5);
195 		dgram->header.pad = 0;
196 	}
197 
198 	return (item);
199 }
200 
201 /*
202  * Re-attach incomplete datagram back to priv.
203  * If there is already another one, then send incomplete. */
204 static void
205 return_export_dgram(priv_p priv, fib_export_p fe, item_p item, int flags)
206 {
207 
208 	/*
209 	 * It may happen on SMP, that some thread has already
210 	 * put its item there, in this case we bail out and
211 	 * send what we have to collector.
212 	 */
213 	mtx_lock(&fe->export_mtx);
214 	if (fe->exp.item == NULL) {
215 		fe->exp.item = item;
216 		mtx_unlock(&fe->export_mtx);
217 	} else {
218 		mtx_unlock(&fe->export_mtx);
219 		export_send(priv, fe, item, flags);
220 	}
221 }
222 
223 /*
224  * The flow is over. Call export_add() and free it. If datagram is
225  * full, then call export_send().
226  */
227 static void
228 expire_flow(priv_p priv, fib_export_p fe, struct flow_entry *fle, int flags)
229 {
230 	struct netflow_export_item exp;
231 	uint16_t version = fle->f.version;
232 
233 	if ((priv->export != NULL) && (version == IPVERSION)) {
234 		exp.item = get_export_dgram(priv, fe);
235 		if (exp.item == NULL) {
236 			priv->nfinfo_export_failed++;
237 			if (priv->export9 != NULL)
238 				priv->nfinfo_export9_failed++;
239 			/* fle definitely contains IPv4 flow. */
240 			uma_zfree_arg(priv->zone, fle, priv);
241 			return;
242 		}
243 
244 		if (export_add(exp.item, fle) > 0)
245 			export_send(priv, fe, exp.item, flags);
246 		else
247 			return_export_dgram(priv, fe, exp.item, NG_QUEUE);
248 	}
249 
250 	if (priv->export9 != NULL) {
251 		exp.item9 = get_export9_dgram(priv, fe, &exp.item9_opt);
252 		if (exp.item9 == NULL) {
253 			priv->nfinfo_export9_failed++;
254 			if (version == IPVERSION)
255 				uma_zfree_arg(priv->zone, fle, priv);
256 #ifdef INET6
257 			else if (version == IP6VERSION)
258 				uma_zfree_arg(priv->zone6, fle, priv);
259 #endif
260 			else
261 				panic("ng_netflow: Unknown IP proto: %d",
262 				    version);
263 			return;
264 		}
265 
266 		if (export9_add(exp.item9, exp.item9_opt, fle) > 0)
267 			export9_send(priv, fe, exp.item9, exp.item9_opt, flags);
268 		else
269 			return_export9_dgram(priv, fe, exp.item9,
270 			    exp.item9_opt, NG_QUEUE);
271 	}
272 
273 	if (version == IPVERSION)
274 		uma_zfree_arg(priv->zone, fle, priv);
275 #ifdef INET6
276 	else if (version == IP6VERSION)
277 		uma_zfree_arg(priv->zone6, fle, priv);
278 #endif
279 }
280 
281 /* Get a snapshot of node statistics */
282 void
283 ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i)
284 {
285 
286 	i->nfinfo_bytes = counter_u64_fetch(priv->nfinfo_bytes);
287 	i->nfinfo_packets = counter_u64_fetch(priv->nfinfo_packets);
288 	i->nfinfo_bytes6 = counter_u64_fetch(priv->nfinfo_bytes6);
289 	i->nfinfo_packets6 = counter_u64_fetch(priv->nfinfo_packets6);
290 	i->nfinfo_sbytes = counter_u64_fetch(priv->nfinfo_sbytes);
291 	i->nfinfo_spackets = counter_u64_fetch(priv->nfinfo_spackets);
292 	i->nfinfo_sbytes6 = counter_u64_fetch(priv->nfinfo_sbytes6);
293 	i->nfinfo_spackets6 = counter_u64_fetch(priv->nfinfo_spackets6);
294 	i->nfinfo_act_exp = counter_u64_fetch(priv->nfinfo_act_exp);
295 	i->nfinfo_inact_exp = counter_u64_fetch(priv->nfinfo_inact_exp);
296 
297 	i->nfinfo_used = uma_zone_get_cur(priv->zone);
298 #ifdef INET6
299 	i->nfinfo_used6 = uma_zone_get_cur(priv->zone6);
300 #endif
301 
302 	i->nfinfo_alloc_failed = priv->nfinfo_alloc_failed;
303 	i->nfinfo_export_failed = priv->nfinfo_export_failed;
304 	i->nfinfo_export9_failed = priv->nfinfo_export9_failed;
305 	i->nfinfo_realloc_mbuf = priv->nfinfo_realloc_mbuf;
306 	i->nfinfo_alloc_fibs = priv->nfinfo_alloc_fibs;
307 	i->nfinfo_inact_t = priv->nfinfo_inact_t;
308 	i->nfinfo_act_t = priv->nfinfo_act_t;
309 }
310 
311 /*
312  * Insert a record into defined slot.
313  *
314  * First we get for us a free flow entry, then fill in all
315  * possible fields in it.
316  *
317  * TODO: consider dropping hash mutex while filling in datagram,
318  * as this was done in previous version. Need to test & profile
319  * to be sure.
320  */
321 static int
322 hash_insert(priv_p priv, struct flow_hash_entry *hsh, struct flow_rec *r,
323 	int plen, uint8_t flags, uint8_t tcp_flags)
324 {
325 	struct flow_entry *fle;
326 	struct sockaddr_in sin, sin_mask;
327 	struct sockaddr_dl rt_gateway;
328 	struct rt_addrinfo info;
329 
330 	mtx_assert(&hsh->mtx, MA_OWNED);
331 
332 	fle = uma_zalloc_arg(priv->zone, priv, M_NOWAIT);
333 	if (fle == NULL) {
334 		priv->nfinfo_alloc_failed++;
335 		return (ENOMEM);
336 	}
337 
338 	/*
339 	 * Now fle is totally ours. It is detached from all lists,
340 	 * we can safely edit it.
341 	 */
342 	fle->f.version = IPVERSION;
343 	bcopy(r, &fle->f.r, sizeof(struct flow_rec));
344 	fle->f.bytes = plen;
345 	fle->f.packets = 1;
346 	fle->f.tcp_flags = tcp_flags;
347 
348 	fle->f.first = fle->f.last = time_uptime;
349 
350 	/*
351 	 * First we do route table lookup on destination address. So we can
352 	 * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases.
353 	 */
354 	if ((flags & NG_NETFLOW_CONF_NODSTLOOKUP) == 0) {
355 		bzero(&sin, sizeof(sin));
356 		sin.sin_len = sizeof(struct sockaddr_in);
357 		sin.sin_family = AF_INET;
358 		sin.sin_addr = fle->f.r.r_dst;
359 
360 		rt_gateway.sdl_len = sizeof(rt_gateway);
361 		sin_mask.sin_len = sizeof(struct sockaddr_in);
362 		bzero(&info, sizeof(info));
363 
364 		info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&rt_gateway;
365 		info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&sin_mask;
366 
367 		if (rib_lookup_info(r->fib, (struct sockaddr *)&sin, NHR_REF, 0,
368 		    &info) == 0) {
369 			fle->f.fle_o_ifx = info.rti_ifp->if_index;
370 
371 			if (info.rti_flags & RTF_GATEWAY &&
372 			    rt_gateway.sdl_family == AF_INET)
373 				fle->f.next_hop =
374 				    ((struct sockaddr_in *)&rt_gateway)->sin_addr;
375 
376 			if (info.rti_addrs & RTA_NETMASK)
377 				fle->f.dst_mask = bitcount32(sin_mask.sin_addr.s_addr);
378 			else if (info.rti_flags & RTF_HOST)
379 				/* Give up. We can't determine mask :( */
380 				fle->f.dst_mask = 32;
381 
382 			rib_free_info(&info);
383 		}
384 	}
385 
386 	/* Do route lookup on source address, to fill in src_mask. */
387 	if ((flags & NG_NETFLOW_CONF_NOSRCLOOKUP) == 0) {
388 		bzero(&sin, sizeof(sin));
389 		sin.sin_len = sizeof(struct sockaddr_in);
390 		sin.sin_family = AF_INET;
391 		sin.sin_addr = fle->f.r.r_src;
392 
393 		sin_mask.sin_len = sizeof(struct sockaddr_in);
394 		bzero(&info, sizeof(info));
395 
396 		info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&sin_mask;
397 
398 		if (rib_lookup_info(r->fib, (struct sockaddr *)&sin, 0, 0,
399 		    &info) == 0) {
400 			if (info.rti_addrs & RTA_NETMASK)
401 				fle->f.src_mask =
402 				    bitcount32(sin_mask.sin_addr.s_addr);
403 			else if (info.rti_flags & RTF_HOST)
404 				/* Give up. We can't determine mask :( */
405 				fle->f.src_mask = 32;
406 		}
407 	}
408 
409 	/* Push new flow at the and of hash. */
410 	TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
411 
412 	return (0);
413 }
414 
415 #ifdef INET6
416 static int
417 hash6_insert(priv_p priv, struct flow_hash_entry *hsh6, struct flow6_rec *r,
418 	int plen, uint8_t flags, uint8_t tcp_flags)
419 {
420 	struct flow6_entry *fle6;
421 	struct sockaddr_in6 sin6, sin6_mask;
422 	struct sockaddr_dl rt_gateway;
423 	struct rt_addrinfo info;
424 
425 	mtx_assert(&hsh6->mtx, MA_OWNED);
426 
427 	fle6 = uma_zalloc_arg(priv->zone6, priv, M_NOWAIT);
428 	if (fle6 == NULL) {
429 		priv->nfinfo_alloc_failed++;
430 		return (ENOMEM);
431 	}
432 
433 	/*
434 	 * Now fle is totally ours. It is detached from all lists,
435 	 * we can safely edit it.
436 	 */
437 
438 	fle6->f.version = IP6VERSION;
439 	bcopy(r, &fle6->f.r, sizeof(struct flow6_rec));
440 	fle6->f.bytes = plen;
441 	fle6->f.packets = 1;
442 	fle6->f.tcp_flags = tcp_flags;
443 
444 	fle6->f.first = fle6->f.last = time_uptime;
445 
446 	/*
447 	 * First we do route table lookup on destination address. So we can
448 	 * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases.
449 	 */
450 	if ((flags & NG_NETFLOW_CONF_NODSTLOOKUP) == 0) {
451 		bzero(&sin6, sizeof(struct sockaddr_in6));
452 		sin6.sin6_len = sizeof(struct sockaddr_in6);
453 		sin6.sin6_family = AF_INET6;
454 		sin6.sin6_addr = r->dst.r_dst6;
455 
456 		rt_gateway.sdl_len = sizeof(rt_gateway);
457 		sin6_mask.sin6_len = sizeof(struct sockaddr_in6);
458 		bzero(&info, sizeof(info));
459 
460 		info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&rt_gateway;
461 		info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&sin6_mask;
462 
463 		if (rib_lookup_info(r->fib, (struct sockaddr *)&sin6, NHR_REF,
464 		    0, &info) == 0) {
465 			fle6->f.fle_o_ifx = info.rti_ifp->if_index;
466 
467 			if (info.rti_flags & RTF_GATEWAY &&
468 			    rt_gateway.sdl_family == AF_INET6)
469 				fle6->f.n.next_hop6 =
470 				    ((struct sockaddr_in6 *)&rt_gateway)->sin6_addr;
471 
472 			fle6->f.dst_mask =
473 			    ip6_masklen(&sin6_mask.sin6_addr, &info);
474 
475 			rib_free_info(&info);
476 		}
477 	}
478 
479 	if ((flags & NG_NETFLOW_CONF_NOSRCLOOKUP) == 0) {
480 		/* Do route lookup on source address, to fill in src_mask. */
481 		bzero(&sin6, sizeof(struct sockaddr_in6));
482 		sin6.sin6_len = sizeof(struct sockaddr_in6);
483 		sin6.sin6_family = AF_INET6;
484 		sin6.sin6_addr = r->src.r_src6;
485 
486 		sin6_mask.sin6_len = sizeof(struct sockaddr_in6);
487 		bzero(&info, sizeof(info));
488 
489 		info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&sin6_mask;
490 
491 		if (rib_lookup_info(r->fib, (struct sockaddr *)&sin6, 0, 0,
492 		    &info) == 0)
493 			fle6->f.src_mask =
494 			    ip6_masklen(&sin6_mask.sin6_addr, &info);
495 	}
496 
497 	/* Push new flow at the and of hash. */
498 	TAILQ_INSERT_TAIL(&hsh6->head, (struct flow_entry *)fle6, fle_hash);
499 
500 	return (0);
501 }
502 #endif
503 
504 
505 /*
506  * Non-static functions called from ng_netflow.c
507  */
508 
509 /* Allocate memory and set up flow cache */
510 void
511 ng_netflow_cache_init(priv_p priv)
512 {
513 	struct flow_hash_entry *hsh;
514 	int i;
515 
516 	/* Initialize cache UMA zone. */
517 	priv->zone = uma_zcreate("NetFlow IPv4 cache",
518 	    sizeof(struct flow_entry), NULL, NULL, NULL, NULL,
519 	    UMA_ALIGN_CACHE, 0);
520 	uma_zone_set_max(priv->zone, CACHESIZE);
521 #ifdef INET6
522 	priv->zone6 = uma_zcreate("NetFlow IPv6 cache",
523 	    sizeof(struct flow6_entry), NULL, NULL, NULL, NULL,
524 	    UMA_ALIGN_CACHE, 0);
525 	uma_zone_set_max(priv->zone6, CACHESIZE);
526 #endif
527 
528 	/* Allocate hash. */
529 	priv->hash = malloc(NBUCKETS * sizeof(struct flow_hash_entry),
530 	    M_NETFLOW_HASH, M_WAITOK | M_ZERO);
531 
532 	/* Initialize hash. */
533 	for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) {
534 		mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF);
535 		TAILQ_INIT(&hsh->head);
536 	}
537 
538 #ifdef INET6
539 	/* Allocate hash. */
540 	priv->hash6 = malloc(NBUCKETS * sizeof(struct flow_hash_entry),
541 	    M_NETFLOW_HASH, M_WAITOK | M_ZERO);
542 
543 	/* Initialize hash. */
544 	for (i = 0, hsh = priv->hash6; i < NBUCKETS; i++, hsh++) {
545 		mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF);
546 		TAILQ_INIT(&hsh->head);
547 	}
548 #endif
549 
550 	priv->nfinfo_bytes = counter_u64_alloc(M_WAITOK);
551 	priv->nfinfo_packets = counter_u64_alloc(M_WAITOK);
552 	priv->nfinfo_bytes6 = counter_u64_alloc(M_WAITOK);
553 	priv->nfinfo_packets6 = counter_u64_alloc(M_WAITOK);
554 	priv->nfinfo_sbytes = counter_u64_alloc(M_WAITOK);
555 	priv->nfinfo_spackets = counter_u64_alloc(M_WAITOK);
556 	priv->nfinfo_sbytes6 = counter_u64_alloc(M_WAITOK);
557 	priv->nfinfo_spackets6 = counter_u64_alloc(M_WAITOK);
558 	priv->nfinfo_act_exp = counter_u64_alloc(M_WAITOK);
559 	priv->nfinfo_inact_exp = counter_u64_alloc(M_WAITOK);
560 
561 	ng_netflow_v9_cache_init(priv);
562 	CTR0(KTR_NET, "ng_netflow startup()");
563 }
564 
565 /* Initialize new FIB table for v5 and v9 */
566 int
567 ng_netflow_fib_init(priv_p priv, int fib)
568 {
569 	fib_export_p	fe = priv_to_fib(priv, fib);
570 
571 	CTR1(KTR_NET, "ng_netflow(): fib init: %d", fib);
572 
573 	if (fe != NULL)
574 		return (0);
575 
576 	if ((fe = malloc(sizeof(struct fib_export), M_NETGRAPH,
577 	    M_NOWAIT | M_ZERO)) == NULL)
578 		return (ENOMEM);
579 
580 	mtx_init(&fe->export_mtx, "export dgram lock", NULL, MTX_DEF);
581 	mtx_init(&fe->export9_mtx, "export9 dgram lock", NULL, MTX_DEF);
582 	fe->fib = fib;
583 	fe->domain_id = fib;
584 
585 	if (atomic_cmpset_ptr((volatile uintptr_t *)&priv->fib_data[fib],
586 	    (uintptr_t)NULL, (uintptr_t)fe) == 0) {
587 		/* FIB already set up by other ISR */
588 		CTR3(KTR_NET, "ng_netflow(): fib init: %d setup %p but got %p",
589 		    fib, fe, priv_to_fib(priv, fib));
590 		mtx_destroy(&fe->export_mtx);
591 		mtx_destroy(&fe->export9_mtx);
592 		free(fe, M_NETGRAPH);
593 	} else {
594 		/* Increase counter for statistics */
595 		CTR3(KTR_NET, "ng_netflow(): fib %d setup to %p (%p)",
596 		    fib, fe, priv_to_fib(priv, fib));
597 		priv->nfinfo_alloc_fibs++;
598 	}
599 
600 	return (0);
601 }
602 
603 /* Free all flow cache memory. Called from node close method. */
604 void
605 ng_netflow_cache_flush(priv_p priv)
606 {
607 	struct flow_entry	*fle, *fle1;
608 	struct flow_hash_entry	*hsh;
609 	struct netflow_export_item exp;
610 	fib_export_p fe;
611 	int i;
612 
613 	bzero(&exp, sizeof(exp));
614 
615 	/*
616 	 * We are going to free probably billable data.
617 	 * Expire everything before freeing it.
618 	 * No locking is required since callout is already drained.
619 	 */
620 	for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++)
621 		TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
622 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
623 			fe = priv_to_fib(priv, fle->f.r.fib);
624 			expire_flow(priv, fe, fle, NG_QUEUE);
625 		}
626 #ifdef INET6
627 	for (hsh = priv->hash6, i = 0; i < NBUCKETS; hsh++, i++)
628 		TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
629 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
630 			fe = priv_to_fib(priv, fle->f.r.fib);
631 			expire_flow(priv, fe, fle, NG_QUEUE);
632 		}
633 #endif
634 
635 	uma_zdestroy(priv->zone);
636 	/* Destroy hash mutexes. */
637 	for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++)
638 		mtx_destroy(&hsh->mtx);
639 
640 	/* Free hash memory. */
641 	if (priv->hash != NULL)
642 		free(priv->hash, M_NETFLOW_HASH);
643 #ifdef INET6
644 	uma_zdestroy(priv->zone6);
645 	/* Destroy hash mutexes. */
646 	for (i = 0, hsh = priv->hash6; i < NBUCKETS; i++, hsh++)
647 		mtx_destroy(&hsh->mtx);
648 
649 	/* Free hash memory. */
650 	if (priv->hash6 != NULL)
651 		free(priv->hash6, M_NETFLOW_HASH);
652 #endif
653 
654 	for (i = 0; i < priv->maxfibs; i++) {
655 		if ((fe = priv_to_fib(priv, i)) == NULL)
656 			continue;
657 
658 		if (fe->exp.item != NULL)
659 			export_send(priv, fe, fe->exp.item, NG_QUEUE);
660 
661 		if (fe->exp.item9 != NULL)
662 			export9_send(priv, fe, fe->exp.item9,
663 			    fe->exp.item9_opt, NG_QUEUE);
664 
665 		mtx_destroy(&fe->export_mtx);
666 		mtx_destroy(&fe->export9_mtx);
667 		free(fe, M_NETGRAPH);
668 	}
669 
670 	counter_u64_free(priv->nfinfo_bytes);
671 	counter_u64_free(priv->nfinfo_packets);
672 	counter_u64_free(priv->nfinfo_bytes6);
673 	counter_u64_free(priv->nfinfo_packets6);
674 	counter_u64_free(priv->nfinfo_sbytes);
675 	counter_u64_free(priv->nfinfo_spackets);
676 	counter_u64_free(priv->nfinfo_sbytes6);
677 	counter_u64_free(priv->nfinfo_spackets6);
678 	counter_u64_free(priv->nfinfo_act_exp);
679 	counter_u64_free(priv->nfinfo_inact_exp);
680 
681 	ng_netflow_v9_cache_flush(priv);
682 }
683 
684 /* Insert packet from into flow cache. */
685 int
686 ng_netflow_flow_add(priv_p priv, fib_export_p fe, struct ip *ip,
687     caddr_t upper_ptr, uint8_t upper_proto, uint8_t flags,
688     unsigned int src_if_index)
689 {
690 	struct flow_entry	*fle, *fle1;
691 	struct flow_hash_entry	*hsh;
692 	struct flow_rec		r;
693 	int			hlen, plen;
694 	int			error = 0;
695 	uint16_t		eproto;
696 	uint8_t			tcp_flags = 0;
697 
698 	bzero(&r, sizeof(r));
699 
700 	if (ip->ip_v != IPVERSION)
701 		return (EINVAL);
702 
703 	hlen = ip->ip_hl << 2;
704 	if (hlen < sizeof(struct ip))
705 		return (EINVAL);
706 
707 	eproto = ETHERTYPE_IP;
708 	/* Assume L4 template by default */
709 	r.flow_type = NETFLOW_V9_FLOW_V4_L4;
710 
711 	r.r_src = ip->ip_src;
712 	r.r_dst = ip->ip_dst;
713 	r.fib = fe->fib;
714 
715 	plen = ntohs(ip->ip_len);
716 
717 	r.r_ip_p = ip->ip_p;
718 	r.r_tos = ip->ip_tos;
719 
720 	r.r_i_ifx = src_if_index;
721 
722 	/*
723 	 * XXX NOTE: only first fragment of fragmented TCP, UDP and
724 	 * ICMP packet will be recorded with proper s_port and d_port.
725 	 * Following fragments will be recorded simply as IP packet with
726 	 * ip_proto = ip->ip_p and s_port, d_port set to zero.
727 	 * I know, it looks like bug. But I don't want to re-implement
728 	 * ip packet assebmling here. Anyway, (in)famous trafd works this way -
729 	 * and nobody complains yet :)
730 	 */
731 	if ((ip->ip_off & htons(IP_OFFMASK)) == 0)
732 		switch(r.r_ip_p) {
733 		case IPPROTO_TCP:
734 		    {
735 			struct tcphdr *tcp;
736 
737 			tcp = (struct tcphdr *)((caddr_t )ip + hlen);
738 			r.r_sport = tcp->th_sport;
739 			r.r_dport = tcp->th_dport;
740 			tcp_flags = tcp->th_flags;
741 			break;
742 		    }
743 		case IPPROTO_UDP:
744 			r.r_ports = *(uint32_t *)((caddr_t )ip + hlen);
745 			break;
746 		}
747 
748 	counter_u64_add(priv->nfinfo_packets, 1);
749 	counter_u64_add(priv->nfinfo_bytes, plen);
750 
751 	/* Find hash slot. */
752 	hsh = &priv->hash[ip_hash(&r)];
753 
754 	mtx_lock(&hsh->mtx);
755 
756 	/*
757 	 * Go through hash and find our entry. If we encounter an
758 	 * entry, that should be expired, purge it. We do a reverse
759 	 * search since most active entries are first, and most
760 	 * searches are done on most active entries.
761 	 */
762 	TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) {
763 		if (bcmp(&r, &fle->f.r, sizeof(struct flow_rec)) == 0)
764 			break;
765 		if ((INACTIVE(fle) && SMALL(fle)) || AGED(fle)) {
766 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
767 			expire_flow(priv, priv_to_fib(priv, fle->f.r.fib),
768 			    fle, NG_QUEUE);
769 			counter_u64_add(priv->nfinfo_act_exp, 1);
770 		}
771 	}
772 
773 	if (fle) {			/* An existent entry. */
774 
775 		fle->f.bytes += plen;
776 		fle->f.packets ++;
777 		fle->f.tcp_flags |= tcp_flags;
778 		fle->f.last = time_uptime;
779 
780 		/*
781 		 * We have the following reasons to expire flow in active way:
782 		 * - it hit active timeout
783 		 * - a TCP connection closed
784 		 * - it is going to overflow counter
785 		 */
786 		if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle) ||
787 		    (fle->f.bytes >= (CNTR_MAX - IF_MAXMTU)) ) {
788 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
789 			expire_flow(priv, priv_to_fib(priv, fle->f.r.fib),
790 			    fle, NG_QUEUE);
791 			counter_u64_add(priv->nfinfo_act_exp, 1);
792 		} else {
793 			/*
794 			 * It is the newest, move it to the tail,
795 			 * if it isn't there already. Next search will
796 			 * locate it quicker.
797 			 */
798 			if (fle != TAILQ_LAST(&hsh->head, fhead)) {
799 				TAILQ_REMOVE(&hsh->head, fle, fle_hash);
800 				TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
801 			}
802 		}
803 	} else				/* A new flow entry. */
804 		error = hash_insert(priv, hsh, &r, plen, flags, tcp_flags);
805 
806 	mtx_unlock(&hsh->mtx);
807 
808 	return (error);
809 }
810 
811 #ifdef INET6
812 /* Insert IPv6 packet from into flow cache. */
813 int
814 ng_netflow_flow6_add(priv_p priv, fib_export_p fe, struct ip6_hdr *ip6,
815     caddr_t upper_ptr, uint8_t upper_proto, uint8_t flags,
816     unsigned int src_if_index)
817 {
818 	struct flow_entry	*fle = NULL, *fle1;
819 	struct flow6_entry	*fle6;
820 	struct flow_hash_entry	*hsh;
821 	struct flow6_rec	r;
822 	int			plen;
823 	int			error = 0;
824 	uint8_t			tcp_flags = 0;
825 
826 	/* check version */
827 	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION)
828 		return (EINVAL);
829 
830 	bzero(&r, sizeof(r));
831 
832 	r.src.r_src6 = ip6->ip6_src;
833 	r.dst.r_dst6 = ip6->ip6_dst;
834 	r.fib = fe->fib;
835 
836 	/* Assume L4 template by default */
837 	r.flow_type = NETFLOW_V9_FLOW_V6_L4;
838 
839 	plen = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr);
840 
841 #if 0
842 	/* XXX: set DSCP/CoS value */
843 	r.r_tos = ip->ip_tos;
844 #endif
845 	if ((flags & NG_NETFLOW_IS_FRAG) == 0) {
846 		switch(upper_proto) {
847 		case IPPROTO_TCP:
848 		    {
849 			struct tcphdr *tcp;
850 
851 			tcp = (struct tcphdr *)upper_ptr;
852 			r.r_ports = *(uint32_t *)upper_ptr;
853 			tcp_flags = tcp->th_flags;
854 			break;
855 		    }
856  		case IPPROTO_UDP:
857 		case IPPROTO_SCTP:
858 			r.r_ports = *(uint32_t *)upper_ptr;
859 			break;
860 		}
861 	}
862 
863 	r.r_ip_p = upper_proto;
864 	r.r_i_ifx = src_if_index;
865 
866 	counter_u64_add(priv->nfinfo_packets6, 1);
867 	counter_u64_add(priv->nfinfo_bytes6, plen);
868 
869 	/* Find hash slot. */
870 	hsh = &priv->hash6[ip6_hash(&r)];
871 
872 	mtx_lock(&hsh->mtx);
873 
874 	/*
875 	 * Go through hash and find our entry. If we encounter an
876 	 * entry, that should be expired, purge it. We do a reverse
877 	 * search since most active entries are first, and most
878 	 * searches are done on most active entries.
879 	 */
880 	TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) {
881 		if (fle->f.version != IP6VERSION)
882 			continue;
883 		fle6 = (struct flow6_entry *)fle;
884 		if (bcmp(&r, &fle6->f.r, sizeof(struct flow6_rec)) == 0)
885 			break;
886 		if ((INACTIVE(fle6) && SMALL(fle6)) || AGED(fle6)) {
887 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
888 			expire_flow(priv, priv_to_fib(priv, fle->f.r.fib), fle,
889 			    NG_QUEUE);
890 			counter_u64_add(priv->nfinfo_act_exp, 1);
891 		}
892 	}
893 
894 	if (fle != NULL) {			/* An existent entry. */
895 		fle6 = (struct flow6_entry *)fle;
896 
897 		fle6->f.bytes += plen;
898 		fle6->f.packets ++;
899 		fle6->f.tcp_flags |= tcp_flags;
900 		fle6->f.last = time_uptime;
901 
902 		/*
903 		 * We have the following reasons to expire flow in active way:
904 		 * - it hit active timeout
905 		 * - a TCP connection closed
906 		 * - it is going to overflow counter
907 		 */
908 		if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle6) ||
909 		    (fle6->f.bytes >= (CNTR_MAX - IF_MAXMTU)) ) {
910 			TAILQ_REMOVE(&hsh->head, fle, fle_hash);
911 			expire_flow(priv, priv_to_fib(priv, fle->f.r.fib), fle,
912 			    NG_QUEUE);
913 			counter_u64_add(priv->nfinfo_act_exp, 1);
914 		} else {
915 			/*
916 			 * It is the newest, move it to the tail,
917 			 * if it isn't there already. Next search will
918 			 * locate it quicker.
919 			 */
920 			if (fle != TAILQ_LAST(&hsh->head, fhead)) {
921 				TAILQ_REMOVE(&hsh->head, fle, fle_hash);
922 				TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
923 			}
924 		}
925 	} else				/* A new flow entry. */
926 		error = hash6_insert(priv, hsh, &r, plen, flags, tcp_flags);
927 
928 	mtx_unlock(&hsh->mtx);
929 
930 	return (error);
931 }
932 #endif
933 
934 /*
935  * Return records from cache to userland.
936  *
937  * TODO: matching particular IP should be done in kernel, here.
938  */
939 int
940 ng_netflow_flow_show(priv_p priv, struct ngnf_show_header *req,
941 struct ngnf_show_header *resp)
942 {
943 	struct flow_hash_entry	*hsh;
944 	struct flow_entry	*fle;
945 	struct flow_entry_data	*data = (struct flow_entry_data *)(resp + 1);
946 #ifdef INET6
947 	struct flow6_entry_data	*data6 = (struct flow6_entry_data *)(resp + 1);
948 #endif
949 	int	i, max;
950 
951 	i = req->hash_id;
952 	if (i > NBUCKETS-1)
953 		return (EINVAL);
954 
955 #ifdef INET6
956 	if (req->version == 6) {
957 		resp->version = 6;
958 		hsh = priv->hash6 + i;
959 		max = NREC6_AT_ONCE;
960 	} else
961 #endif
962 	if (req->version == 4) {
963 		resp->version = 4;
964 		hsh = priv->hash + i;
965 		max = NREC_AT_ONCE;
966 	} else
967 		return (EINVAL);
968 
969 	/*
970 	 * We will transfer not more than NREC_AT_ONCE. More data
971 	 * will come in next message.
972 	 * We send current hash index and current record number in list
973 	 * to userland, and userland should return it back to us.
974 	 * Then, we will restart with new entry.
975 	 *
976 	 * The resulting cache snapshot can be inaccurate if flow expiration
977 	 * is taking place on hash item between userland data requests for
978 	 * this hash item id.
979 	 */
980 	resp->nentries = 0;
981 	for (; i < NBUCKETS; hsh++, i++) {
982 		int list_id;
983 
984 		if (mtx_trylock(&hsh->mtx) == 0) {
985 			/*
986 			 * Requested hash index is not available,
987 			 * relay decision to skip or re-request data
988 			 * to userland.
989 			 */
990 			resp->hash_id = i;
991 			resp->list_id = 0;
992 			return (0);
993 		}
994 
995 		list_id = 0;
996 		TAILQ_FOREACH(fle, &hsh->head, fle_hash) {
997 			if (hsh->mtx.mtx_lock & MTX_CONTESTED) {
998 				resp->hash_id = i;
999 				resp->list_id = list_id;
1000 				mtx_unlock(&hsh->mtx);
1001 				return (0);
1002 			}
1003 
1004 			list_id++;
1005 			/* Search for particular record in list. */
1006 			if (req->list_id > 0) {
1007 				if (list_id < req->list_id)
1008 					continue;
1009 
1010 				/* Requested list position found. */
1011 				req->list_id = 0;
1012 			}
1013 #ifdef INET6
1014 			if (req->version == 6) {
1015 				struct flow6_entry *fle6;
1016 
1017 				fle6 = (struct flow6_entry *)fle;
1018 				bcopy(&fle6->f, data6 + resp->nentries,
1019 				    sizeof(fle6->f));
1020 			} else
1021 #endif
1022 				bcopy(&fle->f, data + resp->nentries,
1023 				    sizeof(fle->f));
1024 			resp->nentries++;
1025 			if (resp->nentries == max) {
1026 				resp->hash_id = i;
1027 				/*
1028 				 * If it was the last item in list
1029 				 * we simply skip to next hash_id.
1030 				 */
1031 				resp->list_id = list_id + 1;
1032 				mtx_unlock(&hsh->mtx);
1033 				return (0);
1034 			}
1035 		}
1036 		mtx_unlock(&hsh->mtx);
1037 	}
1038 
1039 	resp->hash_id = resp->list_id = 0;
1040 
1041 	return (0);
1042 }
1043 
1044 /* We have full datagram in privdata. Send it to export hook. */
1045 static int
1046 export_send(priv_p priv, fib_export_p fe, item_p item, int flags)
1047 {
1048 	struct mbuf *m = NGI_M(item);
1049 	struct netflow_v5_export_dgram *dgram = mtod(m,
1050 					struct netflow_v5_export_dgram *);
1051 	struct netflow_v5_header *header = &dgram->header;
1052 	struct timespec ts;
1053 	int error = 0;
1054 
1055 	/* Fill mbuf header. */
1056 	m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v5_record) *
1057 	   header->count + sizeof(struct netflow_v5_header);
1058 
1059 	/* Fill export header. */
1060 	header->sys_uptime = htonl(MILLIUPTIME(time_uptime));
1061 	getnanotime(&ts);
1062 	header->unix_secs  = htonl(ts.tv_sec);
1063 	header->unix_nsecs = htonl(ts.tv_nsec);
1064 	header->engine_type = 0;
1065 	header->engine_id = fe->domain_id;
1066 	header->pad = 0;
1067 	header->flow_seq = htonl(atomic_fetchadd_32(&fe->flow_seq,
1068 	    header->count));
1069 	header->count = htons(header->count);
1070 
1071 	if (priv->export != NULL)
1072 		NG_FWD_ITEM_HOOK_FLAGS(error, item, priv->export, flags);
1073 	else
1074 		NG_FREE_ITEM(item);
1075 
1076 	return (error);
1077 }
1078 
1079 
1080 /* Add export record to dgram. */
1081 static int
1082 export_add(item_p item, struct flow_entry *fle)
1083 {
1084 	struct netflow_v5_export_dgram *dgram = mtod(NGI_M(item),
1085 					struct netflow_v5_export_dgram *);
1086 	struct netflow_v5_header *header = &dgram->header;
1087 	struct netflow_v5_record *rec;
1088 
1089 	rec = &dgram->r[header->count];
1090 	header->count ++;
1091 
1092 	KASSERT(header->count <= NETFLOW_V5_MAX_RECORDS,
1093 	    ("ng_netflow: export too big"));
1094 
1095 	/* Fill in export record. */
1096 	rec->src_addr = fle->f.r.r_src.s_addr;
1097 	rec->dst_addr = fle->f.r.r_dst.s_addr;
1098 	rec->next_hop = fle->f.next_hop.s_addr;
1099 	rec->i_ifx    = htons(fle->f.fle_i_ifx);
1100 	rec->o_ifx    = htons(fle->f.fle_o_ifx);
1101 	rec->packets  = htonl(fle->f.packets);
1102 	rec->octets   = htonl(fle->f.bytes);
1103 	rec->first    = htonl(MILLIUPTIME(fle->f.first));
1104 	rec->last     = htonl(MILLIUPTIME(fle->f.last));
1105 	rec->s_port   = fle->f.r.r_sport;
1106 	rec->d_port   = fle->f.r.r_dport;
1107 	rec->flags    = fle->f.tcp_flags;
1108 	rec->prot     = fle->f.r.r_ip_p;
1109 	rec->tos      = fle->f.r.r_tos;
1110 	rec->dst_mask = fle->f.dst_mask;
1111 	rec->src_mask = fle->f.src_mask;
1112 	rec->pad1     = 0;
1113 	rec->pad2     = 0;
1114 
1115 	/* Not supported fields. */
1116 	rec->src_as = rec->dst_as = 0;
1117 
1118 	if (header->count == NETFLOW_V5_MAX_RECORDS)
1119 		return (1); /* end of datagram */
1120 	else
1121 		return (0);
1122 }
1123 
1124 /* Periodic flow expiry run. */
1125 void
1126 ng_netflow_expire(void *arg)
1127 {
1128 	struct flow_entry	*fle, *fle1;
1129 	struct flow_hash_entry	*hsh;
1130 	priv_p			priv = (priv_p )arg;
1131 	int			used, i;
1132 
1133 	/*
1134 	 * Going through all the cache.
1135 	 */
1136 	used = uma_zone_get_cur(priv->zone);
1137 	for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) {
1138 		/*
1139 		 * Skip entries, that are already being worked on.
1140 		 */
1141 		if (mtx_trylock(&hsh->mtx) == 0)
1142 			continue;
1143 
1144 		TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
1145 			/*
1146 			 * Interrupt thread wants this entry!
1147 			 * Quick! Quick! Bail out!
1148 			 */
1149 			if (hsh->mtx.mtx_lock & MTX_CONTESTED)
1150 				break;
1151 
1152 			/*
1153 			 * Don't expire aggressively while hash collision
1154 			 * ratio is predicted small.
1155 			 */
1156 			if (used <= (NBUCKETS*2) && !INACTIVE(fle))
1157 				break;
1158 
1159 			if ((INACTIVE(fle) && (SMALL(fle) ||
1160 			    (used > (NBUCKETS*2)))) || AGED(fle)) {
1161 				TAILQ_REMOVE(&hsh->head, fle, fle_hash);
1162 				expire_flow(priv, priv_to_fib(priv,
1163 				    fle->f.r.fib), fle, NG_NOFLAGS);
1164 				used--;
1165 				counter_u64_add(priv->nfinfo_inact_exp, 1);
1166 			}
1167 		}
1168 		mtx_unlock(&hsh->mtx);
1169 	}
1170 
1171 #ifdef INET6
1172 	used = uma_zone_get_cur(priv->zone6);
1173 	for (hsh = priv->hash6, i = 0; i < NBUCKETS; hsh++, i++) {
1174 		struct flow6_entry	*fle6;
1175 
1176 		/*
1177 		 * Skip entries, that are already being worked on.
1178 		 */
1179 		if (mtx_trylock(&hsh->mtx) == 0)
1180 			continue;
1181 
1182 		TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
1183 			fle6 = (struct flow6_entry *)fle;
1184 			/*
1185 			 * Interrupt thread wants this entry!
1186 			 * Quick! Quick! Bail out!
1187 			 */
1188 			if (hsh->mtx.mtx_lock & MTX_CONTESTED)
1189 				break;
1190 
1191 			/*
1192 			 * Don't expire aggressively while hash collision
1193 			 * ratio is predicted small.
1194 			 */
1195 			if (used <= (NBUCKETS*2) && !INACTIVE(fle6))
1196 				break;
1197 
1198 			if ((INACTIVE(fle6) && (SMALL(fle6) ||
1199 			    (used > (NBUCKETS*2)))) || AGED(fle6)) {
1200 				TAILQ_REMOVE(&hsh->head, fle, fle_hash);
1201 				expire_flow(priv, priv_to_fib(priv,
1202 				    fle->f.r.fib), fle, NG_NOFLAGS);
1203 				used--;
1204 				counter_u64_add(priv->nfinfo_inact_exp, 1);
1205 			}
1206 		}
1207 		mtx_unlock(&hsh->mtx);
1208 	}
1209 #endif
1210 
1211 	/* Schedule next expire. */
1212 	callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire,
1213 	    (void *)priv);
1214 }
1215