/*- * Copyright (c) 2004-2005 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 $ * $FreeBSD: src/sys/netgraph/netflow/netflow.c,v 1.29 2008/05/09 23:02:57 julian Exp $ * $DragonFly: src/sys/netgraph7/netflow/netflow.c,v 1.2 2008/06/26 23:05:40 dillon Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ng_message.h" #include "netgraph.h" #include "netflow/netflow.h" #include "netflow/ng_netflow.h" #define NBUCKETS (65536) /* must be power of 2 */ /* This hash is for TCP or UDP packets. */ #define FULL_HASH(addr1, addr2, port1, port2) \ (((addr1 ^ (addr1 >> 16) ^ \ htons(addr2 ^ (addr2 >> 16))) ^ \ port1 ^ htons(port2)) & \ (NBUCKETS - 1)) /* This hash is for all other IP packets. */ #define ADDR_HASH(addr1, addr2) \ ((addr1 ^ (addr1 >> 16) ^ \ htons(addr2 ^ (addr2 >> 16))) & \ (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) /* * Cisco uses milliseconds for uptime. Bad idea, since it overflows * every 48+ days. But we will do same to keep compatibility. This macro * does overflowable multiplication to 1000. */ #define MILLIUPTIME(t) (((t) << 9) + /* 512 */ \ ((t) << 8) + /* 256 */ \ ((t) << 7) + /* 128 */ \ ((t) << 6) + /* 64 */ \ ((t) << 5) + /* 32 */ \ ((t) << 3)) /* 8 */ MALLOC_DECLARE(M_NETFLOW_HASH); MALLOC_DEFINE(M_NETFLOW_HASH, "netflow_hash", "NetFlow hash"); static int export_add(item_p, struct flow_entry *); static int export_send(priv_p, item_p, int flags); /* 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); } } /* This is callback from uma(9), called on alloc. */ static int uma_ctor_flow(void *mem, int size, void *arg, int how) { priv_p priv = (priv_p )arg; if (atomic_load_acq_32(&priv->info.nfinfo_used) >= CACHESIZE) return (ENOMEM); atomic_add_32(&priv->info.nfinfo_used, 1); return (0); } /* This is callback from uma(9), called on free. */ static void uma_dtor_flow(void *mem, int size, void *arg) { priv_p priv = (priv_p )arg; atomic_subtract_32(&priv->info.nfinfo_used, 1); } /* * Detach export datagram from priv, if there is any. * If there is no, allocate a new one. */ static item_p get_export_dgram(priv_p priv) { item_p item = NULL; mtx_lock(&priv->export_mtx); if (priv->export_item != NULL) { item = priv->export_item; priv->export_item = NULL; } mtx_unlock(&priv->export_mtx); if (item == NULL) { struct netflow_v5_export_dgram *dgram; struct mbuf *m; m = m_getcl(MB_DONTWAIT, MT_DATA, M_PKTHDR); if (m == NULL) return (NULL); item = ng_package_data(m, NG_NOFLAGS); if (item == NULL) return (NULL); dgram = mtod(m, struct netflow_v5_export_dgram *); dgram->header.count = 0; dgram->header.version = htons(NETFLOW_V5); } return (item); } /* * Re-attach incomplete datagram back to priv. * If there is already another one, then send incomplete. */ static void return_export_dgram(priv_p priv, item_p item, int flags) { /* * It may happen on SMP, that some thread has already * put its item there, in this case we bail out and * send what we have to collector. */ mtx_lock(&priv->export_mtx); if (priv->export_item == NULL) { priv->export_item = item; mtx_unlock(&priv->export_mtx); } else { mtx_unlock(&priv->export_mtx); export_send(priv, item, flags); } } /* * The flow is over. Call export_add() and free it. If datagram is * full, then call export_send(). */ static __inline void expire_flow(priv_p priv, item_p *item, struct flow_entry *fle, int flags) { if (*item == NULL) *item = get_export_dgram(priv); if (*item == NULL) { atomic_add_32(&priv->info.nfinfo_export_failed, 1); uma_zfree_arg(priv->zone, fle, priv); return; } if (export_add(*item, fle) > 0) { export_send(priv, *item, flags); *item = NULL; } uma_zfree_arg(priv->zone, fle, priv); } /* Get a snapshot of node statistics */ void ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i) { /* XXX: atomic */ memcpy((void *)i, (void *)&priv->info, sizeof(priv->info)); } /* * Insert a record into defined slot. * * First we get for us a free flow entry, then fill in all * possible fields in it. * * TODO: consider dropping hash mutex while filling in datagram, * as this was done in previous version. Need to test & profile * to be sure. */ static __inline int hash_insert(priv_p priv, struct flow_hash_entry *hsh, struct flow_rec *r, int plen, uint8_t tcp_flags) { struct flow_entry *fle; struct sockaddr_in sin; struct rtentry *rt; mtx_assert(&hsh->mtx, MA_OWNED); fle = uma_zalloc_arg(priv->zone, priv, M_WAITOK | M_NULLOK); if (fle == NULL) { atomic_add_32(&priv->info.nfinfo_alloc_failed, 1); 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; fle->f.tcp_flags = tcp_flags; 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(&sin, sizeof(sin)); sin.sin_len = sizeof(struct sockaddr_in); sin.sin_family = AF_INET; sin.sin_addr = fle->f.r.r_dst; /* XXX MRT 0 as a default.. need the m here to get fib */ rt = rtalloc1_fib((struct sockaddr *)&sin, 0, RTF_CLONING, 0); if (rt != NULL) { 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 = bitcount32(((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_LOCKED(rt); } /* Do route lookup on source address, to fill in src_mask. */ bzero(&sin, sizeof(sin)); sin.sin_len = sizeof(struct sockaddr_in); sin.sin_family = AF_INET; sin.sin_addr = fle->f.r.r_src; /* XXX MRT 0 as a default revisit. need the mbuf for fib*/ rt = rtalloc1_fib((struct sockaddr *)&sin, 0, RTF_CLONING, 0); if (rt != NULL) { if (rt_mask(rt)) fle->f.src_mask = bitcount32(((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_LOCKED(rt); } /* Push new flow at the and of hash. */ TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash); return (0); } /* * 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_hash_entry *hsh; int i; /* Initialize cache UMA zone. */ priv->zone = uma_zcreate("NetFlow cache", sizeof(struct flow_entry), uma_ctor_flow, uma_dtor_flow, NULL, NULL, UMA_ALIGN_CACHE, 0); uma_zone_set_max(priv->zone, CACHESIZE); /* Allocate hash. */ MALLOC(priv->hash, struct flow_hash_entry *, NBUCKETS * sizeof(struct flow_hash_entry), M_NETFLOW_HASH, M_WAITOK | M_ZERO); if (priv->hash == NULL) { uma_zdestroy(priv->zone); return (ENOMEM); } /* Initialize hash. */ for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) { mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF); TAILQ_INIT(&hsh->head); } mtx_init(&priv->export_mtx, "export dgram lock", NULL, MTX_DEF); return (0); } /* Free all flow cache memory. Called from node close method. */ void ng_netflow_cache_flush(priv_p priv) { struct flow_entry *fle, *fle1; struct flow_hash_entry *hsh; item_p item = NULL; 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 (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) { TAILQ_REMOVE(&hsh->head, fle, fle_hash); expire_flow(priv, &item, fle, NG_QUEUE); } if (item != NULL) export_send(priv, item, NG_QUEUE); uma_zdestroy(priv->zone); /* Destroy hash mutexes. */ for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) mtx_destroy(&hsh->mtx); /* Free hash memory. */ if (priv->hash) FREE(priv->hash, M_NETFLOW_HASH); mtx_destroy(&priv->export_mtx); } /* Insert packet from into flow cache. */ int ng_netflow_flow_add(priv_p priv, struct ip *ip, iface_p iface, struct ifnet *ifp) { register struct flow_entry *fle, *fle1; struct flow_hash_entry *hsh; struct flow_rec r; item_p item = NULL; int hlen, plen; int error = 0; uint8_t tcp_flags = 0; /* Try to fill flow_rec r */ bzero(&r, sizeof(r)); /* 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; /* Configured in_ifx overrides mbuf's */ if (iface->info.ifinfo_index == 0) { if (ifp != NULL) r.r_i_ifx = ifp->if_index; } else r.r_i_ifx = iface->info.ifinfo_index; /* * 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)) == 0) switch(r.r_ip_p) { case IPPROTO_TCP: { register struct tcphdr *tcp; tcp = (struct tcphdr *)((caddr_t )ip + hlen); r.r_sport = tcp->th_sport; r.r_dport = tcp->th_dport; tcp_flags = tcp->th_flags; break; } case IPPROTO_UDP: r.r_ports = *(uint32_t *)((caddr_t )ip + hlen); break; } /* Update node statistics. XXX: race... */ priv->info.nfinfo_packets ++; priv->info.nfinfo_bytes += plen; /* Find hash slot. */ hsh = &priv->hash[ip_hash(&r)]; mtx_lock(&hsh->mtx); /* * Go through hash and find our entry. If we encounter an * entry, that should be expired, purge it. We do a reverse * search since most active entries are first, and most * searches are done on most active entries. */ TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) { if (bcmp(&r, &fle->f.r, sizeof(struct flow_rec)) == 0) break; if ((INACTIVE(fle) && SMALL(fle)) || AGED(fle)) { TAILQ_REMOVE(&hsh->head, fle, fle_hash); expire_flow(priv, &item, fle, NG_QUEUE); atomic_add_32(&priv->info.nfinfo_act_exp, 1); } } if (fle) { /* An existent entry. */ 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)) ) { TAILQ_REMOVE(&hsh->head, fle, fle_hash); expire_flow(priv, &item, fle, NG_QUEUE); atomic_add_32(&priv->info.nfinfo_act_exp, 1); } else { /* * It is the newest, move it to the tail, * if it isn't there already. Next search will * locate it quicker. */ if (fle != TAILQ_LAST(&hsh->head, fhead)) { TAILQ_REMOVE(&hsh->head, fle, fle_hash); TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash); } } } else /* A new flow entry. */ error = hash_insert(priv, hsh, &r, plen, tcp_flags); mtx_unlock(&hsh->mtx); if (item != NULL) return_export_dgram(priv, item, NG_QUEUE); return (error); } /* * Return records from cache to userland. * * 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_hash_entry *hsh; struct flow_entry *fle; struct ngnf_flows *data; int i; data = (struct ngnf_flows *)resp->data; data->last = 0; data->nentries = 0; /* Check if this is a first run */ if (last == 0) { hsh = priv->hash; i = 0; } else { if (last > NBUCKETS-1) return (EINVAL); hsh = priv->hash + last; i = last; } /* * We will transfer not more than NREC_AT_ONCE. More data * will come in next message. * We send current hash index to userland, and userland should * return it back to us. Then, we will restart with new entry. * * The resulting cache snapshot is inaccurate for the * following reasons: * - we skip locked hash entries * - we bail out, if someone wants our entry * - we skip rest of entry, when hit NREC_AT_ONCE */ for (; i < NBUCKETS; hsh++, i++) { if (mtx_trylock(&hsh->mtx) == 0) continue; TAILQ_FOREACH(fle, &hsh->head, fle_hash) { if (mtx_contested(&hsh->mtx) break; bcopy(&fle->f, &(data->entries[data->nentries]), sizeof(fle->f)); data->nentries++; if (data->nentries == NREC_AT_ONCE) { mtx_unlock(&hsh->mtx); if (++i < NBUCKETS) data->last = i; return (0); } } mtx_unlock(&hsh->mtx); } return (0); } /* We have full datagram in privdata. Send it to export hook. */ static int export_send(priv_p priv, item_p item, int flags) { struct mbuf *m = NGI_M(item); struct netflow_v5_export_dgram *dgram = mtod(m, struct netflow_v5_export_dgram *); struct netflow_v5_header *header = &dgram->header; struct timespec ts; int error = 0; /* Fill mbuf header. */ m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v5_record) * header->count + sizeof(struct netflow_v5_header); /* Fill export header. */ header->sys_uptime = htonl(MILLIUPTIME(time_uptime)); getnanotime(&ts); header->unix_secs = htonl(ts.tv_sec); header->unix_nsecs = htonl(ts.tv_nsec); header->engine_type = 0; header->engine_id = 0; header->pad = 0; header->flow_seq = htonl(atomic_fetchadd_32(&priv->flow_seq, header->count)); header->count = htons(header->count); if (priv->export != NULL) NG_FWD_ITEM_HOOK_FLAGS(error, item, priv->export, flags); else NG_FREE_ITEM(item); return (error); } /* Add export record to dgram. */ static int export_add(item_p item, struct flow_entry *fle) { struct netflow_v5_export_dgram *dgram = mtod(NGI_M(item), struct netflow_v5_export_dgram *); struct netflow_v5_header *header = &dgram->header; struct netflow_v5_record *rec; rec = &dgram->r[header->count]; header->count ++; KASSERT(header->count <= NETFLOW_V5_MAX_RECORDS, ("ng_netflow: export too big")); /* 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(MILLIUPTIME(fle->f.first)); rec->last = htonl(MILLIUPTIME(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; /* Not supported fields. */ rec->src_as = rec->dst_as = 0; if (header->count == NETFLOW_V5_MAX_RECORDS) return (1); /* end of datagram */ else return (0); } /* Periodic flow expiry run. */ void ng_netflow_expire(void *arg) { struct flow_entry *fle, *fle1; struct flow_hash_entry *hsh; priv_p priv = (priv_p )arg; item_p item = NULL; uint32_t used; int i; /* * Going through all the cache. */ for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) { /* * Skip entries, that are already being worked on. */ if (mtx_trylock(&hsh->mtx) == 0) continue; used = atomic_load_acq_32(&priv->info.nfinfo_used); TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) { /* * Interrupt thread wants this entry! * Quick! Quick! Bail out! */ if (mtx_contested(&hsh->mtx)) break; /* * Don't expire aggressively while hash collision * ratio is predicted small. */ if (used <= (NBUCKETS*2) && !INACTIVE(fle)) break; if ((INACTIVE(fle) && (SMALL(fle) || (used > (NBUCKETS*2)))) || AGED(fle)) { TAILQ_REMOVE(&hsh->head, fle, fle_hash); expire_flow(priv, &item, fle, NG_NOFLAGS); used--; atomic_add_32(&priv->info.nfinfo_inact_exp, 1); } } mtx_unlock(&hsh->mtx); } if (item != NULL) return_export_dgram(priv, item, NG_NOFLAGS); /* Schedule next expire. */ callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire, (void *)priv); }