/*- * Copyright (c) 2004 Gleb Smirnoff * Copyright (c) 2001-2003 Roman V. Palagin * All rights reserved. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. * * $SourceForge: netflow.c,v 1.41 2004/09/05 11:41:10 glebius Exp $ */ static const char rcs_id[] = "@(#) $FreeBSD$"; #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define NBUCKETS (4096) /* must be power of 2 */ /* This hash is for TCP or UDP packets */ #define FULL_HASH(addr1,addr2,port1,port2)\ (((addr1 >> 16) ^ \ (addr2 & 0x00FF) ^ \ ((port1 ^ port2) << 8) )& \ (NBUCKETS - 1)) /* This hash for all other IP packets */ #define ADDR_HASH(addr1,addr2)\ (((addr1 >> 16) ^ \ (addr2 & 0x00FF) )& \ (NBUCKETS - 1)) /* Macros to shorten logical constructions */ /* XXX: priv must exist in namespace */ #define INACTIVE(fle) (time_uptime - fle->f.last > priv->info.nfinfo_inact_t) #define AGED(fle) (time_uptime - fle->f.first > priv->info.nfinfo_act_t) #define ISFREE(fle) (fle->f.packets == 0) /* * 4 is a magical number: statistically number of 4-packet flows is * bigger than 5,6,7...-packet flows by an order of magnitude. Most UDP/ICMP * scans are 1 packet (~ 90% of flow cache). TCP scans are 2-packet in case * of reachable host and 4-packet otherwise. */ #define SMALL(fle) (fle->f.packets <= 4) MALLOC_DECLARE(M_NETFLOW); MALLOC_DEFINE(M_NETFLOW, "NetFlow", "flow cache"); static int export_add(priv_p , struct flow_entry *); static int export_send(priv_p ); /* Generate hash for a given flow record */ static __inline uint32_t ip_hash(struct flow_rec *r) { switch (r->r_ip_p) { case IPPROTO_TCP: case IPPROTO_UDP: return FULL_HASH(r->r_src.s_addr, r->r_dst.s_addr, r->r_sport, r->r_dport); default: return ADDR_HASH(r->r_src.s_addr, r->r_dst.s_addr); } } /* Lookup for record in given slot */ static __inline struct flow_entry * hash_lookup(struct flow_hash_entry *h, int slot, struct flow_rec *r) { struct flow_entry *fle; LIST_FOREACH(fle, &(h[slot].head), fle_hash) if (bcmp(r, &fle->f.r, sizeof(struct flow_rec)) == 0) return (fle); return (NULL); } /* Get a flow entry from free list */ static __inline struct flow_entry * alloc_flow(priv_p priv, int *flows) { register struct flow_entry *fle; mtx_lock(&priv->free_mtx); if (SLIST_EMPTY(&priv->free_list)) { mtx_unlock(&priv->free_mtx); return(NULL); } fle = SLIST_FIRST(&priv->free_list); SLIST_REMOVE_HEAD(&priv->free_list, fle_free); priv->info.nfinfo_used++; priv->info.nfinfo_free--; if (flows != NULL) *flows = priv->info.nfinfo_used; mtx_unlock(&priv->free_mtx); return (fle); } /* Insert flow entry into a free list. */ static __inline int free_flow(priv_p priv, struct flow_entry *fle) { int flows; mtx_lock(&priv->free_mtx); fle->f.packets = 0; SLIST_INSERT_HEAD(&priv->free_list, fle, fle_free); flows = priv->info.nfinfo_used--; priv->info.nfinfo_free++; mtx_unlock(&priv->free_mtx); return flows; } #define NGNF_GETUSED(priv, rval) do { \ mtx_lock(&priv->free_mtx); \ rval = priv->info.nfinfo_used; \ mtx_unlock(&priv->free_mtx); \ } while (0) /* Insert flow entry into expire list. */ /* XXX: Flow must be detached from work queue, but not from cache */ static __inline void expire_flow(priv_p priv, struct flow_entry *fle) { mtx_assert(&priv->work_mtx, MA_OWNED); LIST_REMOVE(fle, fle_hash); mtx_lock(&priv->expire_mtx); SLIST_INSERT_HEAD(&priv->expire_list, fle, fle_free); mtx_unlock(&priv->expire_mtx); } /* Get a snapshot of node statistics */ void ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i) { mtx_lock(&priv->free_mtx); memcpy((void *)i, (void *)&priv->info, sizeof(priv->info)); mtx_unlock(&priv->free_mtx); } /* Calculate number of bits in netmask */ #define g21 0x55555555ul /* = 0101_0101_0101_0101_0101_0101_0101_0101 */ #define g22 0x33333333ul /* = 0011_0011_0011_0011_0011_0011_0011_0011 */ #define g23 0x0f0f0f0ful /* = 0000_1111_0000_1111_0000_1111_0000_1111 */ static __inline u_char bit_count(uint32_t v) { v = (v & g21) + ((v >> 1) & g21); v = (v & g22) + ((v >> 2) & g22); v = (v + (v >> 4)) & g23; return (v + (v >> 8) + (v >> 16) + (v >> 24)) & 0x3f; } /* * Insert a record into defined slot. * * First we get for us a free flow entry, then fill in all * possible fields in it. Then obtain lock on flow cache * and insert flow entry. */ static __inline int hash_insert(priv_p priv, int slot, struct flow_rec *r, int plen) { struct flow_hash_entry *h = priv->hash; struct flow_entry *fle; struct route ro; struct sockaddr_in *sin; fle = alloc_flow(priv, NULL); if (fle == NULL) return (ENOMEM); /* * Now fle is totally ours. It is detached from all lists, * we can safely edit it. */ bcopy(r, &fle->f.r, sizeof(struct flow_rec)); fle->f.bytes = plen; fle->f.packets = 1; priv->info.nfinfo_bytes += plen; fle->f.first = fle->f.last = time_uptime; /* * First we do route table lookup on destination address. So we can * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases. */ bzero((caddr_t)&ro, sizeof(ro)); sin = (struct sockaddr_in *)&ro.ro_dst; sin->sin_len = sizeof(*sin); sin->sin_family = AF_INET; sin->sin_addr = fle->f.r.r_dst; rtalloc_ign(&ro, RTF_CLONING); if (ro.ro_rt != NULL) { struct rtentry *rt = ro.ro_rt; fle->f.fle_o_ifx = rt->rt_ifp->if_index; if (rt->rt_flags & RTF_GATEWAY && rt->rt_gateway->sa_family == AF_INET) fle->f.next_hop = ((struct sockaddr_in *)(rt->rt_gateway))->sin_addr; if (rt_mask(rt)) fle->f.dst_mask = bit_count(((struct sockaddr_in *)rt_mask(rt))->sin_addr.s_addr); else if (rt->rt_flags & RTF_HOST) /* Give up. We can't determine mask :( */ fle->f.dst_mask = 32; RTFREE(ro.ro_rt); } /* Do route lookup on source address, to fill in src_mask. */ bzero((caddr_t)&ro, sizeof(ro)); sin = (struct sockaddr_in *)&ro.ro_dst; sin->sin_len = sizeof(*sin); sin->sin_family = AF_INET; sin->sin_addr = fle->f.r.r_src; rtalloc_ign(&ro, RTF_CLONING); if (ro.ro_rt != NULL) { struct rtentry *rt = ro.ro_rt; if (rt_mask(rt)) fle->f.src_mask = bit_count(((struct sockaddr_in *)rt_mask(rt))->sin_addr.s_addr); else if (rt->rt_flags & RTF_HOST) /* Give up. We can't determine mask :( */ fle->f.src_mask = 32; RTFREE(ro.ro_rt); } /* Push new flow entry into flow cache */ mtx_lock(&priv->work_mtx); LIST_INSERT_HEAD(&(h[slot].head), fle, fle_hash); TAILQ_INSERT_TAIL(&priv->work_queue, fle, fle_work); mtx_unlock(&priv->work_mtx); return (0); } static __inline int make_flow_rec(struct mbuf **m, int *plen, struct flow_rec *r, uint8_t *tcp_flags, u_int16_t i_ifx) { register struct ip *ip; int hlen; int error = 0; ip = mtod(*m, struct ip*); /* check version */ if (ip->ip_v != IPVERSION) return (EINVAL); /* verify min header length */ hlen = ip->ip_hl << 2; if (hlen < sizeof(struct ip)) return (EINVAL); r->r_src = ip->ip_src; r->r_dst = ip->ip_dst; /* save packet length */ *plen = ntohs(ip->ip_len); r->r_ip_p = ip->ip_p; r->r_tos = ip->ip_tos; if ((*m)->m_pkthdr.rcvif) r->r_i_ifx = (*m)->m_pkthdr.rcvif->if_index; else r->r_i_ifx = i_ifx; /* * XXX NOTE: only first fragment of fragmented TCP, UDP and * ICMP packet will be recorded with proper s_port and d_port. * Following fragments will be recorded simply as IP packet with * ip_proto = ip->ip_p and s_port, d_port set to zero. * I know, it looks like bug. But I don't want to re-implement * ip packet assebmling here. Anyway, (in)famous trafd works this way - * and nobody complains yet :) */ if(ip->ip_off & htons(IP_OFFMASK)) return (0); /* skip IP header */ m_adj(*m, hlen); switch(r->r_ip_p) { case IPPROTO_TCP: { register struct tcphdr *tcp; /* verify that packet is not truncated */ if (CHECK_MLEN(*m, sizeof(struct tcphdr))) ERROUT(EINVAL); if (CHECK_PULLUP(*m, sizeof(struct tcphdr))) ERROUT(ENOBUFS); tcp = mtod(*m, struct tcphdr*); r->r_sport = tcp->th_sport; r->r_dport = tcp->th_dport; *tcp_flags = tcp->th_flags; break; } case IPPROTO_UDP: /* verify that packet is not truncated */ if (CHECK_MLEN(*m, sizeof(struct udphdr))) ERROUT(EINVAL); if (CHECK_PULLUP(*m, sizeof(struct udphdr))) ERROUT(ENOBUFS); r->r_ports = *(mtod(*m, uint32_t *)); break; } done: return (error); } /* * Non-static functions called from ng_netflow.c */ /* Allocate memory and set up flow cache */ int ng_netflow_cache_init(priv_p priv) { struct flow_entry *fle; int i; /* allocate cache */ MALLOC(priv->cache, struct flow_entry *, CACHESIZE * sizeof(struct flow_entry), M_NETFLOW, M_WAITOK | M_ZERO); if (priv->cache == NULL) return (ENOMEM); /* allocate hash */ MALLOC(priv->hash, struct flow_hash_entry *, NBUCKETS * sizeof(struct flow_hash_entry), M_NETFLOW, M_WAITOK | M_ZERO); if (priv->hash == NULL) { FREE(priv->cache, M_NETFLOW); return (ENOMEM); } TAILQ_INIT(&priv->work_queue); SLIST_INIT(&priv->free_list); SLIST_INIT(&priv->expire_list); mtx_init(&priv->work_mtx, "ng_netflow cache mutex", NULL, MTX_DEF); mtx_init(&priv->free_mtx, "ng_netflow free mutex", NULL, MTX_DEF); mtx_init(&priv->expire_mtx, "ng_netflow expire mutex", NULL, MTX_DEF); /* build free list */ for (i = 0, fle = priv->cache; i < CACHESIZE; i++, fle++) SLIST_INSERT_HEAD(&priv->free_list, fle, fle_free); priv->info.nfinfo_free = CACHESIZE; return (0); } /* Free all flow cache memory. Called from node close method. */ void ng_netflow_cache_flush(priv_p priv) { register struct flow_entry *fle; int i; /* * We are going to free probably billable data. * Expire everything before freeing it. * No locking is required since callout is already drained. */ for (i = 0, fle = priv->cache; i < CACHESIZE; i++, fle++) if (!ISFREE(fle)) /* ignore errors now */ (void )export_add(priv, fle); mtx_destroy(&priv->work_mtx); mtx_destroy(&priv->free_mtx); mtx_destroy(&priv->expire_mtx); /* free hash memory */ if (priv->hash) FREE(priv->hash, M_NETFLOW); /* free flow cache */ if (priv->cache) FREE(priv->cache, M_NETFLOW); } /* Insert packet from &m into flow cache. */ int ng_netflow_flow_add(priv_p priv, struct mbuf **m, iface_p iface) { struct flow_hash_entry *h = priv->hash; register struct flow_entry *fle; struct flow_rec r; int plen; int error = 0; uint32_t slot; uint8_t tcp_flags = 0; /* Try to fill *rec */ bzero(&r, sizeof(r)); if ((error = make_flow_rec(m, &plen, &r, &tcp_flags, iface->info.ifinfo_index))) return (error); slot = ip_hash(&r); mtx_lock(&priv->work_mtx); /* Update node statistics. */ priv->info.nfinfo_packets ++; priv->info.nfinfo_bytes += plen; fle = hash_lookup(h, slot, &r); /* New flow entry or existent? */ if (fle) { /* an existent entry */ TAILQ_REMOVE(&priv->work_queue, fle, fle_work); fle->f.bytes += plen; fle->f.packets ++; fle->f.tcp_flags |= tcp_flags; fle->f.last = time_uptime; /* * We have the following reasons to expire flow in active way: * - it hit active timeout * - a TCP connection closed * - it is going to overflow counter */ if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle) || (fle->f.bytes >= (UINT_MAX - IF_MAXMTU)) ) expire_flow(priv, fle); else TAILQ_INSERT_TAIL(&priv->work_queue, fle, fle_work); mtx_unlock(&priv->work_mtx); } else { /* a new flow entry */ mtx_unlock(&priv->work_mtx); return hash_insert(priv, slot, &r, plen); } mtx_assert(&priv->work_mtx, MA_NOTOWNED); mtx_assert(&priv->expire_mtx, MA_NOTOWNED); mtx_assert(&priv->free_mtx, MA_NOTOWNED); return (0); } /* * Return records from cache. netgraph(4) guarantees us that we * are locked against ng_netflow_rcvdata(). However we can * work with ng_netflow_expire() in parrallel. XXX: Is it dangerous? * * TODO: matching particular IP should be done in kernel, here. */ int ng_netflow_flow_show(priv_p priv, uint32_t last, struct ng_mesg *resp) { struct flow_entry *fle; struct ngnf_flows *data; data = (struct ngnf_flows *)resp->data; data->last = 0; data->nentries = 0; /* Check if this is a first run */ if (last == 0) fle = priv->cache; else { if (last > CACHESIZE-1) return (EINVAL); fle = priv->cache + last; } /* * We will transfer not more than NREC_AT_ONCE. More data * will come in next message. * We send current stop point to userland, and userland should return * it back to us. */ for (; last < CACHESIZE; fle++, last++) { if (ISFREE(fle)) continue; bcopy(&fle->f, &(data->entries[data->nentries]), sizeof(fle->f)); data->nentries ++; if (data->nentries == NREC_AT_ONCE) { if (++last < CACHESIZE) data->last = (++fle - priv->cache); return (0); } } return (0); } /* We have full datagram in privdata. Send it to export hook. */ static int export_send(priv_p priv) { struct netflow_v5_header *header = &priv->dgram.header; struct timespec ts; struct mbuf *m; int error = 0; int mlen; header->sys_uptime = htonl(time_uptime); getnanotime(&ts); header->unix_secs = htonl(ts.tv_sec); header->unix_nsecs = htonl(ts.tv_nsec); /* Flow sequence contains number of first record */ header->flow_seq = htonl(priv->flow_seq - header->count); mlen = sizeof(struct netflow_v5_header) + sizeof(struct netflow_v5_record) * header->count; header->count = htons(header->count); if ((m = m_devget((caddr_t)header, mlen, 0, NULL, NULL)) == NULL) { printf("ng_netflow: m_devget() failed, losing export dgram\n"); header->count = 0; return(ENOBUFS); } header->count = 0; /* Giant is required in sosend() at this moment. */ NET_LOCK_GIANT(); NG_SEND_DATA_ONLY(error, priv->export, m); NET_UNLOCK_GIANT(); if (error) NG_FREE_M(m); return (error); } /* Create export datagram. */ static int export_add(priv_p priv, struct flow_entry *fle) { struct netflow_v5_header *header = &priv->dgram.header; struct netflow_v5_record *rec; if (header->count == 0 ) { /* first record */ rec = &priv->dgram.r[0]; header->count = 1; } else { /* continue filling datagram */ rec = &priv->dgram.r[header->count]; header->count ++; } /* Fill in export record */ rec->src_addr = fle->f.r.r_src.s_addr; rec->dst_addr = fle->f.r.r_dst.s_addr; rec->next_hop = fle->f.next_hop.s_addr; rec->i_ifx = htons(fle->f.fle_i_ifx); rec->o_ifx = htons(fle->f.fle_o_ifx); rec->packets = htonl(fle->f.packets); rec->octets = htonl(fle->f.bytes); rec->first = htonl(fle->f.first); rec->last = htonl(fle->f.last); rec->s_port = fle->f.r.r_sport; rec->d_port = fle->f.r.r_dport; rec->flags = fle->f.tcp_flags; rec->prot = fle->f.r.r_ip_p; rec->tos = fle->f.r.r_tos; rec->dst_mask = fle->f.dst_mask; rec->src_mask = fle->f.src_mask; priv->flow_seq++; if (header->count == NETFLOW_V5_MAX_RECORDS) /* end of datagram */ return export_send(priv); return (0); } /* Periodic flow expiry run. */ void ng_netflow_expire(void *arg) { register struct flow_entry *fle, *fle1; priv_p priv = (priv_p )arg; uint32_t used; int error = 0; /* First pack actively expired entries */ mtx_lock(&priv->expire_mtx); while (!SLIST_EMPTY(&(priv->expire_list))) { fle = SLIST_FIRST(&(priv->expire_list)); SLIST_REMOVE_HEAD(&(priv->expire_list), fle_free); mtx_unlock(&priv->expire_mtx); /* * While we have dropped the lock, expire_flow() may * insert another flow into top of the list. * This is not harmful for us, since we have already * detached our own. */ if ((error = export_add(priv, fle)) != 0) printf("ng_netflow: export_add() failed: %u\n", error); (void )free_flow(priv, fle); mtx_lock(&priv->expire_mtx); } mtx_unlock(&priv->expire_mtx); NGNF_GETUSED(priv, used); mtx_lock(&priv->work_mtx); TAILQ_FOREACH_SAFE(fle, &(priv->work_queue), fle_work, fle1) { /* * When cache size has not reached CACHELOWAT yet, we keep both * inactive and active flows in cache. Doing this, we reduce number * of exports, since many inactive flows may wake up and continue * their life. However, we make an exclusion for scans. It is very * rare situation that inactive 1-packet flow will wake up. * When cache has reached CACHELOWAT, we expire all inactive flows, * until cache gets of sane size. */ if (used <= CACHELOWAT && !INACTIVE(fle)) goto finish; if (INACTIVE(fle) && (SMALL(fle) || (used > CACHELOWAT))) { /* Detach flow entry from cache */ LIST_REMOVE(fle, fle_hash); TAILQ_REMOVE(&priv->work_queue, fle, fle_work); /* * While we are sending to collector, unlock cache. * XXX: it can happen, however with a small probability, * that item, we are holding now, can be moved to the top * of flow cache by node thread. In this case our expire * thread stops checking. Since this is not fatal we will * just ignore it now. */ mtx_unlock(&priv->work_mtx); if ((error = export_add(priv, fle)) != 0) printf("ng_netflow: export_add() failed: %u\n", error); used = free_flow(priv, fle); mtx_lock(&priv->work_mtx); } } finish: mtx_unlock(&priv->work_mtx); mtx_assert(&priv->expire_mtx, MA_NOTOWNED); mtx_assert(&priv->free_mtx, MA_NOTOWNED); /* schedule next expire */ callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire, (void *)priv); }