HAMMER 60I/Many: Mirroring
[dragonfly.git] / sys / netinet / ip_flow.c
blobcd71e6bc143223d2b89f6baab899069786b49d3c
1 /*-
2 * Copyright (c) 1998 The NetBSD Foundation, Inc.
3 * All rights reserved.
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.
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.
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.
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 1.14 2008/05/14 11:59:24 sephe Exp $
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>
49 #include <machine/smp.h>
51 #include <net/if.h>
52 #include <net/route.h>
53 #include <net/netisr.h>
54 #include <net/netmsg2.h>
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>
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
67 #define IPFLOW_RTENTRY_ISDOWN(rt) \
68 (((rt)->rt_flags & RTF_UP) == 0 || ((rt)->rt_ifp->if_flags & IFF_UP) == 0)
70 #define ipflow_inuse ipflow_inuse_pcpu[mycpuid]
71 #define ipflows ipflows_pcpu[mycpuid]
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;
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");
82 static MALLOC_DEFINE(M_IPFLOW, "ip_flow", "IP flow");
84 static unsigned
85 ipflow_hash(struct in_addr dst, struct in_addr src, unsigned tos)
87 unsigned hash = tos;
88 int idx;
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);
95 static struct ipflow *
96 ipflow_lookup(const struct ip *ip)
98 unsigned hash;
99 struct ipflow *ipf;
101 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
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);
112 crit_exit();
114 return ipf;
118 ipflow_fastforward(struct mbuf *m, lwkt_serialize_t serializer)
120 struct ip *ip;
121 struct ipflow *ipf;
122 struct rtentry *rt;
123 struct sockaddr *dst;
124 struct ifnet *ifp;
125 int error;
128 * Are we forwarding packets? Big enough for an IP packet?
130 if (!ipforwarding || !ipflow_active || m->m_len < sizeof(struct ip))
131 return 0;
134 * IP header with no option and valid version and length
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;
142 * Find a flow.
144 ipf = ipflow_lookup(ip);
145 if (ipf == NULL)
146 return 0;
149 * Route and interface still up?
151 rt = ipf->ipf_ro.ro_rt;
152 if (IPFLOW_RTENTRY_ISDOWN(rt))
153 return 0;
154 ifp = rt->rt_ifp;
157 * Packet size OK? TTL?
159 if (m->m_pkthdr.len > ifp->if_mtu || ip->ip_ttl <= IPTTLDEC)
160 return 0;
163 * Everything checks out and so we can forward this packet.
164 * Modify the TTL and incrementally change the checksum.
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);
173 * Send the packet on its way. All we can get back is ENOBUFS
175 ipf->ipf_uses++;
176 ipf->ipf_timer = IPFLOW_TIMER;
178 if (rt->rt_flags & RTF_GATEWAY)
179 dst = rt->rt_gateway;
180 else
181 dst = &ipf->ipf_ro.ro_dst;
183 if (serializer)
184 lwkt_serialize_exit(serializer);
186 error = ifp->if_output(ifp, m, dst, rt);
187 if (error) {
188 if (error == ENOBUFS)
189 ipf->ipf_dropped++;
190 else
191 ipf->ipf_errors++;
194 if (serializer)
195 lwkt_serialize_enter(serializer);
196 return 1;
199 static void
200 ipflow_addstats(struct ipflow *ipf)
202 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
203 ipstat.ips_cantforward += ipf->ipf_errors + ipf->ipf_dropped;
204 ipstat.ips_forward += ipf->ipf_uses;
205 ipstat.ips_fastforward += ipf->ipf_uses;
208 static void
209 ipflow_free(struct ipflow *ipf)
212 * Remove the flow from the hash table (at elevated IPL).
213 * Once it's off the list, we can deal with it at normal
214 * network IPL.
216 crit_enter();
217 LIST_REMOVE(ipf, ipf_next);
219 KKASSERT(ipflow_inuse > 0);
220 ipflow_inuse--;
221 crit_exit();
223 ipflow_addstats(ipf);
224 RTFREE(ipf->ipf_ro.ro_rt);
225 kfree(ipf, M_IPFLOW);
228 static struct ipflow *
229 ipflow_reap(void)
231 struct ipflow *ipf, *maybe_ipf = NULL;
232 int idx;
234 crit_enter();
235 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
236 ipf = LIST_FIRST(&ipflows[idx]);
237 while (ipf != NULL) {
239 * If this no longer points to a valid route
240 * reclaim it.
242 if ((ipf->ipf_ro.ro_rt->rt_flags & RTF_UP) == 0)
243 goto done;
246 * choose the one that's been least recently used
247 * or has had the least uses in the last 1.5
248 * intervals.
250 if (maybe_ipf == NULL ||
251 ipf->ipf_timer < maybe_ipf->ipf_timer ||
252 (ipf->ipf_timer == maybe_ipf->ipf_timer &&
253 ipf->ipf_last_uses + ipf->ipf_uses <
254 maybe_ipf->ipf_last_uses + maybe_ipf->ipf_uses))
255 maybe_ipf = ipf;
256 ipf = LIST_NEXT(ipf, ipf_next);
259 ipf = maybe_ipf;
260 done:
262 * Remove the entry from the flow table.
264 LIST_REMOVE(ipf, ipf_next);
265 crit_exit();
267 ipflow_addstats(ipf);
268 RTFREE(ipf->ipf_ro.ro_rt);
269 return ipf;
272 static void
273 ipflow_timo_dispatch(struct netmsg *nmsg)
275 struct ipflow *ipf;
276 int idx;
278 crit_enter();
279 lwkt_replymsg(&nmsg->nm_lmsg, 0); /* reply ASAP */
281 for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
282 ipf = LIST_FIRST(&ipflows[idx]);
283 while (ipf != NULL) {
284 struct ipflow *next_ipf = LIST_NEXT(ipf, ipf_next);
286 if (--ipf->ipf_timer == 0) {
287 ipflow_free(ipf);
288 } else {
289 ipf->ipf_last_uses = ipf->ipf_uses;
290 ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
291 ipstat.ips_forward += ipf->ipf_uses;
292 ipstat.ips_fastforward += ipf->ipf_uses;
293 ipf->ipf_uses = 0;
295 ipf = next_ipf;
298 crit_exit();
301 static void
302 ipflow_timo_ipi(void *arg __unused)
304 struct lwkt_msg *msg = &ipflow_timo_netmsgs[mycpuid].nm_lmsg;
306 crit_enter();
307 if (msg->ms_flags & MSGF_DONE)
308 lwkt_sendmsg(cpu_portfn(mycpuid), msg);
309 crit_exit();
312 void
313 ipflow_slowtimo(void)
315 #ifdef SMP
316 lwkt_send_ipiq_mask(smp_active_mask, ipflow_timo_ipi, NULL);
317 #else
318 ipflow_timo_ipi(NULL);
319 #endif
322 static void
323 ipflow_create_oncpu(const struct route *ro, struct mbuf *m)
325 const struct ip *const ip = mtod(m, struct ip *);
326 struct ipflow *ipf;
327 unsigned hash;
330 * See if an existing flow struct exists. If so remove it from it's
331 * list and free the old route. If not, try to malloc a new one
332 * (if we aren't at our limit).
334 ipf = ipflow_lookup(ip);
335 if (ipf == NULL) {
336 if (ipflow_inuse == IPFLOW_MAX) {
337 ipf = ipflow_reap();
338 } else {
339 ipf = kmalloc(sizeof(*ipf), M_IPFLOW,
340 M_INTWAIT | M_NULLOK);
341 if (ipf == NULL)
342 return;
343 ipflow_inuse++;
345 bzero(ipf, sizeof(*ipf));
346 } else if (IPFLOW_RTENTRY_ISDOWN(ipf->ipf_ro.ro_rt)) {
347 crit_enter();
348 LIST_REMOVE(ipf, ipf_next);
349 crit_exit();
351 ipflow_addstats(ipf);
352 RTFREE(ipf->ipf_ro.ro_rt);
353 ipf->ipf_uses = ipf->ipf_last_uses = 0;
354 ipf->ipf_errors = ipf->ipf_dropped = 0;
355 } else {
357 * The route entry cached in ipf is still up,
358 * this could happen while the ipf installation
359 * is in transition state.
360 * XXX should not happen on UP box
362 return;
366 * Fill in the updated information.
368 ipf->ipf_ro = *ro;
369 ro->ro_rt->rt_refcnt++;
370 ipf->ipf_dst = ip->ip_dst;
371 ipf->ipf_src = ip->ip_src;
372 ipf->ipf_tos = ip->ip_tos;
373 ipf->ipf_timer = IPFLOW_TIMER;
376 * Insert into the approriate bucket of the flow table.
378 hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
379 crit_enter();
380 LIST_INSERT_HEAD(&ipflows[hash], ipf, ipf_next);
381 crit_exit();
384 #ifdef SMP
386 static void
387 ipflow_create_dispatch(struct netmsg *nmsg)
389 struct netmsg_packet *nmp = (struct netmsg_packet *)nmsg;
390 struct sockaddr_in *sin;
391 struct route ro;
392 int nextcpu;
394 bzero(&ro, sizeof(ro));
395 sin = (struct sockaddr_in *)&ro.ro_dst;
396 sin->sin_family = AF_INET;
397 sin->sin_len = sizeof(struct sockaddr_in);
398 sin->sin_addr.s_addr = (in_addr_t)nmsg->nm_lmsg.u.ms_result32;
400 rtalloc_ign(&ro, RTF_PRCLONING);
401 if (ro.ro_rt != NULL) {
402 ipflow_create_oncpu(&ro, nmp->nm_packet);
403 RTFREE(ro.ro_rt);
406 nextcpu = mycpuid + 1;
407 if (nextcpu < ncpus)
408 lwkt_forwardmsg(cpu_portfn(nextcpu), &nmsg->nm_lmsg);
409 else
410 m_freem(nmp->nm_packet);
413 #endif /* SMP */
415 void
416 ipflow_create(const struct route *ro, struct mbuf *m)
418 const struct ip *const ip = mtod(m, struct ip *);
419 #ifdef SMP
420 struct netmsg_packet *nmp;
421 struct netmsg *nmsg;
422 int nextcpu;
423 #endif
426 * Don't create cache entries for ICMP messages.
428 if (!ipflow_active || ip->ip_p == IPPROTO_ICMP) {
429 m_freem(m);
430 return;
433 #ifdef SMP
434 nmp = &m->m_hdr.mh_netmsg;
435 nmsg = &nmp->nm_netmsg;
437 netmsg_init(nmsg, &netisr_apanic_rport, 0, ipflow_create_dispatch);
438 nmp->nm_packet = m;
439 nmsg->nm_lmsg.u.ms_result32 =
440 ((const struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr;
442 if (mycpuid == 0) {
443 ipflow_create_oncpu(ro, m);
444 nextcpu = 1;
445 } else {
446 nextcpu = 0;
448 if (nextcpu < ncpus)
449 lwkt_sendmsg(cpu_portfn(nextcpu), &nmsg->nm_lmsg);
450 else
451 m_freem(m);
452 #else
453 ipflow_create_oncpu(ro, m);
454 m_freem(m);
455 #endif
458 static void
459 ipflow_init(void)
461 char oid_name[32];
462 int i;
464 for (i = 0; i < ncpus; ++i) {
465 netmsg_init(&ipflow_timo_netmsgs[i], &netisr_adone_rport, 0,
466 ipflow_timo_dispatch);
468 ksnprintf(oid_name, sizeof(oid_name), "inuse%d", i);
470 SYSCTL_ADD_INT(NULL,
471 SYSCTL_STATIC_CHILDREN(_net_inet_ip_ipflow),
472 OID_AUTO, oid_name, CTLFLAG_RD, &ipflow_inuse_pcpu[i], 0,
473 "# of ip flow being used");
476 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipflow_init, 0);