/*- * Copyright (c) 1998 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by the 3am Software Foundry ("3am"). It was developed by Matt Thomas. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: src/sys/netinet/ip_flow.c,v 1.9.2.2 2001/11/04 17:35:31 luigi Exp $ * $DragonFly: src/sys/netinet/ip_flow.c,v 1.2 2003/06/17 04:28:51 dillon Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define IPFLOW_TIMER (5 * PR_SLOWHZ) #define IPFLOW_HASHBITS 6 /* should not be a multiple of 8 */ #define IPFLOW_HASHSIZE (1 << IPFLOW_HASHBITS) static LIST_HEAD(ipflowhead, ipflow) ipflows[IPFLOW_HASHSIZE]; static int ipflow_inuse; #define IPFLOW_MAX 256 static int ipflow_active = 0; SYSCTL_INT(_net_inet_ip, IPCTL_FASTFORWARDING, fastforwarding, CTLFLAG_RW, &ipflow_active, 0, "Enable flow-based IP forwarding"); static MALLOC_DEFINE(M_IPFLOW, "ip_flow", "IP flow"); static unsigned ipflow_hash( struct in_addr dst, struct in_addr src, unsigned tos) { unsigned hash = tos; int idx; for (idx = 0; idx < 32; idx += IPFLOW_HASHBITS) hash += (dst.s_addr >> (32 - idx)) + (src.s_addr >> idx); return hash & (IPFLOW_HASHSIZE-1); } static struct ipflow * ipflow_lookup( const struct ip *ip) { unsigned hash; struct ipflow *ipf; hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos); ipf = LIST_FIRST(&ipflows[hash]); while (ipf != NULL) { if (ip->ip_dst.s_addr == ipf->ipf_dst.s_addr && ip->ip_src.s_addr == ipf->ipf_src.s_addr && ip->ip_tos == ipf->ipf_tos) break; ipf = LIST_NEXT(ipf, ipf_next); } return ipf; } int ipflow_fastforward( struct mbuf *m) { struct ip *ip; struct ipflow *ipf; struct rtentry *rt; struct sockaddr *dst; int error; /* * Are we forwarding packets? Big enough for an IP packet? */ if (!ipforwarding || !ipflow_active || m->m_len < sizeof(struct ip)) return 0; /* * IP header with no option and valid version and length */ ip = mtod(m, struct ip *); if (ip->ip_v != IPVERSION || ip->ip_hl != (sizeof(struct ip) >> 2) || ntohs(ip->ip_len) > m->m_pkthdr.len) return 0; /* * Find a flow. */ if ((ipf = ipflow_lookup(ip)) == NULL) return 0; /* * Route and interface still up? */ rt = ipf->ipf_ro.ro_rt; if ((rt->rt_flags & RTF_UP) == 0 || (rt->rt_ifp->if_flags & IFF_UP) == 0) return 0; /* * Packet size OK? TTL? */ if (m->m_pkthdr.len > rt->rt_ifp->if_mtu || ip->ip_ttl <= IPTTLDEC) return 0; /* * Everything checks out and so we can forward this packet. * Modify the TTL and incrementally change the checksum. */ ip->ip_ttl -= IPTTLDEC; if (ip->ip_sum >= htons(0xffff - (IPTTLDEC << 8))) { ip->ip_sum += htons(IPTTLDEC << 8) + 1; } else { ip->ip_sum += htons(IPTTLDEC << 8); } /* * Send the packet on its way. All we can get back is ENOBUFS */ ipf->ipf_uses++; ipf->ipf_timer = IPFLOW_TIMER; if (rt->rt_flags & RTF_GATEWAY) dst = rt->rt_gateway; else dst = &ipf->ipf_ro.ro_dst; if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) { if (error == ENOBUFS) ipf->ipf_dropped++; else ipf->ipf_errors++; } return 1; } static void ipflow_addstats( struct ipflow *ipf) { ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses; ipstat.ips_cantforward += ipf->ipf_errors + ipf->ipf_dropped; ipstat.ips_forward += ipf->ipf_uses; ipstat.ips_fastforward += ipf->ipf_uses; } static void ipflow_free( struct ipflow *ipf) { int s; /* * Remove the flow from the hash table (at elevated IPL). * Once it's off the list, we can deal with it at normal * network IPL. */ s = splimp(); LIST_REMOVE(ipf, ipf_next); splx(s); ipflow_addstats(ipf); RTFREE(ipf->ipf_ro.ro_rt); ipflow_inuse--; free(ipf, M_IPFLOW); } static struct ipflow * ipflow_reap( void) { struct ipflow *ipf, *maybe_ipf = NULL; int idx; int s; for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) { ipf = LIST_FIRST(&ipflows[idx]); while (ipf != NULL) { /* * If this no longer points to a valid route * reclaim it. */ if ((ipf->ipf_ro.ro_rt->rt_flags & RTF_UP) == 0) goto done; /* * choose the one that's been least recently used * or has had the least uses in the last 1.5 * intervals. */ if (maybe_ipf == NULL || ipf->ipf_timer < maybe_ipf->ipf_timer || (ipf->ipf_timer == maybe_ipf->ipf_timer && ipf->ipf_last_uses + ipf->ipf_uses < maybe_ipf->ipf_last_uses + maybe_ipf->ipf_uses)) maybe_ipf = ipf; ipf = LIST_NEXT(ipf, ipf_next); } } ipf = maybe_ipf; done: /* * Remove the entry from the flow table. */ s = splimp(); LIST_REMOVE(ipf, ipf_next); splx(s); ipflow_addstats(ipf); RTFREE(ipf->ipf_ro.ro_rt); return ipf; } void ipflow_slowtimo( void) { struct ipflow *ipf; int idx; for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) { ipf = LIST_FIRST(&ipflows[idx]); while (ipf != NULL) { struct ipflow *next_ipf = LIST_NEXT(ipf, ipf_next); if (--ipf->ipf_timer == 0) { ipflow_free(ipf); } else { ipf->ipf_last_uses = ipf->ipf_uses; ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses; ipstat.ips_forward += ipf->ipf_uses; ipstat.ips_fastforward += ipf->ipf_uses; ipf->ipf_uses = 0; } ipf = next_ipf; } } } void ipflow_create( const struct route *ro, struct mbuf *m) { const struct ip *const ip = mtod(m, struct ip *); struct ipflow *ipf; unsigned hash; int s; /* * Don't create cache entries for ICMP messages. */ if (!ipflow_active || ip->ip_p == IPPROTO_ICMP) return; /* * See if an existing flow struct exists. If so remove it from it's * list and free the old route. If not, try to malloc a new one * (if we aren't at our limit). */ ipf = ipflow_lookup(ip); if (ipf == NULL) { if (ipflow_inuse == IPFLOW_MAX) { ipf = ipflow_reap(); } else { ipf = (struct ipflow *) malloc(sizeof(*ipf), M_IPFLOW, M_NOWAIT); if (ipf == NULL) return; ipflow_inuse++; } bzero((caddr_t) ipf, sizeof(*ipf)); } else { s = splimp(); LIST_REMOVE(ipf, ipf_next); splx(s); ipflow_addstats(ipf); RTFREE(ipf->ipf_ro.ro_rt); ipf->ipf_uses = ipf->ipf_last_uses = 0; ipf->ipf_errors = ipf->ipf_dropped = 0; } /* * Fill in the updated information. */ ipf->ipf_ro = *ro; ro->ro_rt->rt_refcnt++; ipf->ipf_dst = ip->ip_dst; ipf->ipf_src = ip->ip_src; ipf->ipf_tos = ip->ip_tos; ipf->ipf_timer = IPFLOW_TIMER; /* * Insert into the approriate bucket of the flow table. */ hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos); s = splimp(); LIST_INSERT_HEAD(&ipflows[hash], ipf, ipf_next); splx(s); }