/* * Copyright (c) 1998-2002 Luigi Rizzo * * Work partly supported by: Cisco Systems, Inc. - NSITE lab, RTP, NC * * 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 ``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 REGENTS 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. * * $FreeBSD$ */ /* * This code implements bridging in FreeBSD. It only acts on ethernet * interfaces, including VLANs (others are still usable for routing). * A FreeBSD host can implement multiple logical bridges, called * "clusters". Each cluster is made of a set of interfaces, and * identified by a "cluster-id" which is a number in the range 1..2^16-1. * * Bridging is enabled by the sysctl variable * net.link.ether.bridge * the grouping of interfaces into clusters is done with * net.link.ether.bridge_cfg * containing a list of interfaces each optionally followed by * a colon and the cluster it belongs to (1 is the default). * Separators can be * spaces, commas or tabs, e.g. * net.link.ether.bridge_cfg="fxp0:2 fxp1:2 dc0 dc1:1" * Optionally bridged packets can be passed through the firewall, * this is controlled by the variable * net.link.ether.bridge_ipfw * * For each cluster there is a descriptor (cluster_softc) storing * the following data structures: * - a hash table with the MAC address and destination interface for each * known node. The table is indexed using a hash of the source address. * - an array with the MAC addresses of the interfaces used in the cluster. * * Input packets are tapped near the beginning of ether_input(), and * analysed by bridge_in(). Depending on the result, the packet * can be forwarded to one or more output interfaces using bdg_forward(), * and/or sent to the upper layer (e.g. in case of multicast). * * Output packets are intercepted near the end of ether_output(). * The correct destination is selected by bridge_dst_lookup(), * and then forwarding is done by bdg_forward(). * * The arp code is also modified to let a machine answer to requests * irrespective of the port the request came from. * * In case of loops in the bridging topology, the bridge detects this * event and temporarily mutes output bridging on one of the ports. * Periodically, interfaces are unmuted by bdg_timeout(). * Muting is only implemented as a safety measure, and also as * a mechanism to support a user-space implementation of the spanning * tree algorithm. * * To build a bridging kernel, use the following option * option BRIDGE * and then at runtime set the sysctl variable to enable bridging. * * Only one interface per cluster is supposed to have addresses set (but * there are no substantial problems if you set addresses for none or * for more than one interface). * Bridging will act before routing, but nothing prevents a machine * from doing both (modulo bugs in the implementation...). * * THINGS TO REMEMBER * - bridging is incompatible with multicast routing on the same * machine. There is not an easy fix to this. * - be very careful when bridging VLANs * - loop detection is still not very robust. */ #include #include #include #include #include #include /* for net/if.h */ #include /* string functions */ #include #include #include /* for ipfilter */ #include #include #include #include /* for struct arpcom */ #include #include #include #include /* for struct arpcom */ #include #include #include #include /*--------------------*/ /* * For each cluster, source MAC addresses are stored into a hash * table which locates the port they reside on. */ #define HASH_SIZE 8192 /* Table size, must be a power of 2 */ typedef struct hash_table { /* each entry. */ struct ifnet * name; u_char etheraddr[6]; u_int16_t used; /* also, padding */ } bdg_hash_table ; /* * The hash function applied to MAC addresses. Out of the 6 bytes, * the last ones tend to vary more. Since we are on a little endian machine, * we have to do some gimmick... */ #define HASH_FN(addr) ( \ ntohs( ((u_int16_t *)addr)[1] ^ ((u_int16_t *)addr)[2] ) & (HASH_SIZE -1)) /* * This is the data structure where local addresses are stored. */ struct bdg_addr { u_char etheraddr[6] ; u_int16_t _padding ; }; /* * The configuration of each cluster includes the cluster id, a pointer to * the hash table, and an array of local MAC addresses (of size "ports"). */ struct cluster_softc { u_int16_t cluster_id; u_int16_t ports; bdg_hash_table *ht; struct bdg_addr *my_macs; /* local MAC addresses */ }; extern struct protosw inetsw[]; /* from netinet/ip_input.c */ extern u_char ip_protox[]; /* from netinet/ip_input.c */ static int n_clusters; /* number of clusters */ static struct cluster_softc *clusters; #define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE) #define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE #define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster) #define BDG_SAMECLUSTER(ifp,src) \ (src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) ) #ifdef __i386__ #define BDG_MATCH(a,b) ( \ ((u_int16_t *)(a))[2] == ((u_int16_t *)(b))[2] && \ *((u_int32_t *)(a)) == *((u_int32_t *)(b)) ) #define IS_ETHER_BROADCAST(a) ( \ *((u_int32_t *)(a)) == 0xffffffff && \ ((u_int16_t *)(a))[2] == 0xffff ) #else /* for machines that do not support unaligned access */ #define BDG_MATCH(a,b) (!bcmp(a, b, ETHER_ADDR_LEN) ) #define IS_ETHER_BROADCAST(a) (!bcmp(a, "\377\377\377\377\377\377", 6)) #endif /* * For timing-related debugging, you can use the following macros. * remember, rdtsc() only works on Pentium-class machines quad_t ticks; DDB(ticks = rdtsc();) ... interesting code ... DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;) * */ #define DDB(x) x #define DEB(x) static int bdginit(void); static void parse_bdg_cfg(void); static int bdg_ipf; /* IPFilter enabled in bridge */ static int bdg_ipfw; #if 0 /* debugging only */ static char *bdg_dst_names[] = { "BDG_NULL ", "BDG_BCAST ", "BDG_MCAST ", "BDG_LOCAL ", "BDG_DROP ", "BDG_UNKNOWN ", "BDG_IN ", "BDG_OUT ", "BDG_FORWARD " }; #endif /* * System initialization */ static struct bdg_stats bdg_stats ; static struct callout_handle bdg_timeout_h ; /* * Add an interface to a cluster, possibly creating a new entry in * the cluster table. This requires reallocation of the table and * updating pointers in ifp2sc. */ static struct cluster_softc * add_cluster(u_int16_t cluster_id, struct arpcom *ac) { struct cluster_softc *c = NULL; int i; for (i = 0; i < n_clusters ; i++) if (clusters[i].cluster_id == cluster_id) goto found; /* Not found, need to reallocate */ c = malloc((1+n_clusters) * sizeof (*c), M_IFADDR, M_DONTWAIT | M_ZERO); if (c == NULL) {/* malloc failure */ printf("-- bridge: cannot add new cluster\n"); return NULL; } c[n_clusters].ht = (struct hash_table *) malloc(HASH_SIZE * sizeof(struct hash_table), M_IFADDR, M_WAITOK | M_ZERO); if (c[n_clusters].ht == NULL) { printf("-- bridge: cannot allocate hash table for new cluster\n"); free(c, M_IFADDR); return NULL; } c[n_clusters].my_macs = (struct bdg_addr *) malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr), M_IFADDR, M_WAITOK | M_ZERO); if (c[n_clusters].my_macs == NULL) { printf("-- bridge: cannot allocate mac addr table for new cluster\n"); free(c[n_clusters].ht, M_IFADDR); free(c, M_IFADDR); return NULL; } c[n_clusters].cluster_id = cluster_id; c[n_clusters].ports = 0; /* * now copy old descriptors here */ if (n_clusters > 0) { for (i=0; i < n_clusters; i++) c[i] = clusters[i]; /* * and finally update pointers in ifp2sc */ for (i = 0 ; i < if_index && i < BDG_MAX_PORTS; i++) if (ifp2sc[i].cluster != NULL) ifp2sc[i].cluster = c + (ifp2sc[i].cluster - clusters); free(clusters, M_IFADDR); } clusters = c; i = n_clusters; /* index of cluster entry */ n_clusters++; found: c = clusters + i; /* the right cluster ... */ bcopy(ac->ac_enaddr, &(c->my_macs[c->ports]), 6); c->ports++; return c; } /* * Turn off bridging, by clearing promisc mode on the interface, * marking the interface as unused, and clearing the name in the * stats entry. * Also dispose the hash tables associated with the clusters. */ static void bridge_off(void) { struct ifnet *ifp ; int i, s; DEB(printf("bridge_off: n_clusters %d\n", n_clusters);) TAILQ_FOREACH(ifp, &ifnet, if_link) { struct bdg_softc *b; if (ifp->if_index >= BDG_MAX_PORTS) continue; /* make sure we do not go beyond the end */ b = &(ifp2sc[ifp->if_index]); if ( b->flags & IFF_BDG_PROMISC ) { s = splimp(); ifpromisc(ifp, 0); splx(s); b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ; DEB(printf(">> now %s%d promisc OFF if_flags 0x%x bdg_flags 0x%x\n", ifp->if_name, ifp->if_unit, ifp->if_flags, b->flags);) } b->flags &= ~(IFF_USED) ; b->cluster = NULL; bdg_stats.s[ifp->if_index].name[0] = '\0'; } /* flush_tables */ s = splimp(); for (i=0; i < n_clusters; i++) { free(clusters[i].ht, M_IFADDR); free(clusters[i].my_macs, M_IFADDR); } if (clusters != NULL) free(clusters, M_IFADDR); clusters = NULL; n_clusters =0; splx(s); } /* * set promisc mode on the interfaces we use. */ static void bridge_on(void) { struct ifnet *ifp ; int s ; TAILQ_FOREACH(ifp, &ifnet, if_link) { struct bdg_softc *b = &ifp2sc[ifp->if_index]; if ( !(b->flags & IFF_USED) ) continue ; if ( !( ifp->if_flags & IFF_UP) ) { s = splimp(); if_up(ifp); splx(s); } if ( !(b->flags & IFF_BDG_PROMISC) ) { int ret ; s = splimp(); ret = ifpromisc(ifp, 1); splx(s); b->flags |= IFF_BDG_PROMISC ; DEB(printf(">> now %s%d promisc ON if_flags 0x%x bdg_flags 0x%x\n", ifp->if_name, ifp->if_unit, ifp->if_flags, b->flags);) } if (b->flags & IFF_MUTE) { DEB(printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);) b->flags &= ~IFF_MUTE; } } } /** * reconfigure bridge. * This is also done every time we attach or detach an interface. * Main use is to make sure that we do not bridge on some old * (ejected) device. So, it would be really useful to have a * pointer to the modified device as an argument. Without it, we * have to scan all interfaces. */ static void reconfigure_bridge(void) { bridge_off(); if (do_bridge) { if (if_index >= BDG_MAX_PORTS) { printf("-- sorry too many interfaces (%d, max is %d)," " disabling bridging\n", if_index, BDG_MAX_PORTS); do_bridge=0; return; } parse_bdg_cfg(); bridge_on(); } } static char bridge_cfg[1024]; /* in BSS so initialized to all NULs */ /* * parse the config string, set IFF_USED, name and cluster_id * for all interfaces found. * The config string is a list of "if[:cluster]" with * a number of possible separators (see "sep"). In particular the * use of the space lets you set bridge_cfg with the output from * "ifconfig -l" */ static void parse_bdg_cfg() { char *p, *beg ; int l, cluster; static char *sep = ", \t"; for (p = bridge_cfg; *p ; p++) { struct ifnet *ifp; int found = 0; char c; if (index(sep, *p)) /* skip separators */ continue ; /* names are lowercase and digits */ for ( beg = p ; islower(*p) || isdigit(*p) ; p++ ) ; l = p - beg ; /* length of name string */ if (l == 0) /* invalid name */ break ; if ( *p != ':' ) /* no ':', assume default cluster 1 */ cluster = 1 ; else /* fetch cluster */ cluster = strtoul( p+1, &p, 10); c = *p; *p = '\0'; /* * now search in interface list for a matching name */ TAILQ_FOREACH(ifp, &ifnet, if_link) { char buf[IFNAMSIZ]; snprintf(buf, sizeof(buf), "%s%d", ifp->if_name, ifp->if_unit); if (!strncmp(beg, buf, max(l, strlen(buf)))) { struct bdg_softc *b = &ifp2sc[ifp->if_index]; if (ifp->if_type != IFT_ETHER && ifp->if_type != IFT_L2VLAN) { printf("%s is not an ethernet, continue\n", buf); continue; } if (b->flags & IFF_USED) { printf("%s already used, skipping\n", buf); break; } b->cluster = add_cluster(htons(cluster), (struct arpcom *)ifp); b->flags |= IFF_USED ; sprintf(bdg_stats.s[ifp->if_index].name, "%s%d:%d", ifp->if_name, ifp->if_unit, cluster); DEB(printf("--++ found %s next c %d\n", bdg_stats.s[ifp->if_index].name, c);) found = 1; break ; } } if (!found) printf("interface %s Not found in bridge\n", beg); *p = c; if (c == '\0') break; /* no more */ } } /* * handler for net.link.ether.bridge */ static int sysctl_bdg(SYSCTL_HANDLER_ARGS) { int error, oldval = do_bridge ; error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); DEB( printf("called sysctl for bridge name %s arg2 %d val %d->%d\n", oidp->oid_name, oidp->oid_arg2, oldval, do_bridge); ) if (oldval != do_bridge) reconfigure_bridge(); return error ; } /* * handler for net.link.ether.bridge_cfg */ static int sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS) { int error = 0 ; char old_cfg[1024] ; strcpy(old_cfg, bridge_cfg) ; error = sysctl_handle_string(oidp, bridge_cfg, oidp->oid_arg2, req); DEB( printf("called sysctl for bridge name %s arg2 %d err %d val %s->%s\n", oidp->oid_name, oidp->oid_arg2, error, old_cfg, bridge_cfg); ) if (strcmp(old_cfg, bridge_cfg)) reconfigure_bridge(); return error ; } static int sysctl_refresh(SYSCTL_HANDLER_ARGS) { if (req->newptr) reconfigure_bridge(); return 0; } SYSCTL_DECL(_net_link_ether); SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_cfg, CTLTYPE_STRING|CTLFLAG_RW, &bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A", "Bridge configuration"); SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge, CTLTYPE_INT|CTLFLAG_RW, &do_bridge, 0, &sysctl_bdg, "I", "Bridging"); SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW, &bdg_ipfw,0,"Pass bridged pkts through firewall"); SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipf, CTLFLAG_RW, &bdg_ipf, 0,"Pass bridged pkts through IPFilter"); /* * The follow macro declares a variable, and maps it to * a SYSCTL_INT entry with the same name. */ #define SY(parent, var, comment) \ static int var ; \ SYSCTL_INT(parent, OID_AUTO, var, CTLFLAG_RW, &(var), 0, comment); int bdg_ipfw_drops; SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_drop, CTLFLAG_RW, &bdg_ipfw_drops,0,""); int bdg_ipfw_colls; SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_collisions, CTLFLAG_RW, &bdg_ipfw_colls,0,""); SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_refresh, CTLTYPE_INT|CTLFLAG_WR, NULL, 0, &sysctl_refresh, "I", "iface refresh"); #if 1 /* diagnostic vars */ SY(_net_link_ether, verbose, "Be verbose"); SY(_net_link_ether, bdg_split_pkts, "Packets split in bdg_forward"); SY(_net_link_ether, bdg_thru, "Packets through bridge"); SY(_net_link_ether, bdg_copied, "Packets copied in bdg_forward"); SY(_net_link_ether, bdg_dropped, "Packets dropped in bdg_forward"); SY(_net_link_ether, bdg_copy, "Force copy in bdg_forward"); SY(_net_link_ether, bdg_predict, "Correctly predicted header location"); SY(_net_link_ether, bdg_fw_avg, "Cycle counter avg"); SY(_net_link_ether, bdg_fw_ticks, "Cycle counter item"); SY(_net_link_ether, bdg_fw_count, "Cycle counter count"); #endif SYSCTL_STRUCT(_net_link_ether, PF_BDG, bdgstats, CTLFLAG_RD, &bdg_stats , bdg_stats, "bridge statistics"); static int bdg_loops ; /* * called periodically to flush entries etc. */ static void bdg_timeout(void *dummy) { static int slowtimer; /* in BSS so initialized to 0 */ if (do_bridge) { static int age_index = 0 ; /* index of table position to age */ int l = age_index + HASH_SIZE/4 ; int i; /* * age entries in the forwarding table. */ if (l > HASH_SIZE) l = HASH_SIZE ; for (i=0; i= HASH_SIZE) age_index = 0 ; if (--slowtimer <= 0 ) { slowtimer = 5 ; bridge_on() ; /* we just need unmute, really */ bdg_loops = 0 ; } } bdg_timeout_h = timeout(bdg_timeout, NULL, 2*hz ); } /* * Find the right pkt destination: * BDG_BCAST is a broadcast * BDG_MCAST is a multicast * BDG_LOCAL is for a local address * BDG_DROP must be dropped * other ifp of the dest. interface (incl.self) * * We assume this is only called for interfaces for which bridging * is enabled, i.e. BDG_USED(ifp) is true. */ static __inline struct ifnet * bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c) { struct ifnet *dst ; int index ; struct bdg_addr *p ; bdg_hash_table *bt; /* pointer to entry in hash table */ if (IS_ETHER_BROADCAST(eh->ether_dhost)) return BDG_BCAST ; if (eh->ether_dhost[0] & 1) return BDG_MCAST ; /* * Lookup local addresses in case one matches. */ for (index = c->ports, p = c->my_macs; index ; index--, p++ ) if (BDG_MATCH(p->etheraddr, eh->ether_dhost) ) return BDG_LOCAL ; /* * Look for a possible destination in table */ index= HASH_FN( eh->ether_dhost ); bt = &(c->ht[index]); dst = bt->name; if ( dst && BDG_MATCH( bt->etheraddr, eh->ether_dhost) ) return dst ; else return BDG_UNKNOWN ; } /** * bridge_in() is invoked to perform bridging decision on input packets. * * On Input: * eh Ethernet header of the incoming packet. * ifp interface the packet is coming from. * * On Return: destination of packet, one of * BDG_BCAST broadcast * BDG_MCAST multicast * BDG_LOCAL is only for a local address (do not forward) * BDG_DROP drop the packet * ifp ifp of the destination interface. * * Forwarding is not done directly to give a chance to some drivers * to fetch more of the packet, or simply drop it completely. */ static struct ifnet * bridge_in(struct ifnet *ifp, struct ether_header *eh) { int index; struct ifnet *dst , *old ; bdg_hash_table *bt; /* location in hash table */ int dropit = BDG_MUTED(ifp) ; /* * hash the source address */ index= HASH_FN(eh->ether_shost); bt = &(ifp2sc[ifp->if_index].cluster->ht[index]); bt->used = 1 ; old = bt->name ; if ( old ) { /* the entry is valid. */ if (!BDG_MATCH( eh->ether_shost, bt->etheraddr) ) { bdg_ipfw_colls++ ; bt->name = NULL ; } else if (old != ifp) { /* * Found a loop. Either a machine has moved, or there * is a misconfiguration/reconfiguration of the network. * First, do not forward this packet! * Record the relocation anyways; then, if loops persist, * suspect a reconfiguration and disable forwarding * from the old interface. */ bt->name = ifp ; /* relocate address */ printf("-- loop (%d) %6D to %s%d from %s%d (%s)\n", bdg_loops, eh->ether_shost, ".", ifp->if_name, ifp->if_unit, old->if_name, old->if_unit, BDG_MUTED(old) ? "muted":"active"); dropit = 1 ; if ( !BDG_MUTED(old) ) { if (++bdg_loops > 10) BDG_MUTE(old) ; } } } /* * now write the source address into the table */ if (bt->name == NULL) { DEB(printf("new addr %6D at %d for %s%d\n", eh->ether_shost, ".", index, ifp->if_name, ifp->if_unit);) bcopy(eh->ether_shost, bt->etheraddr, 6); bt->name = ifp ; } dst = bridge_dst_lookup(eh, ifp2sc[ifp->if_index].cluster); /* * bridge_dst_lookup can return the following values: * BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp. * For muted interfaces, or when we detect a loop, the first 3 are * changed in BDG_LOCAL (we still listen to incoming traffic), * and others to BDG_DROP (no use for the local host). * Also, for incoming packets, ifp is changed to BDG_DROP if ifp == src. * These changes are not necessary for outgoing packets from ether_output(). */ BDG_STAT(ifp, BDG_IN); switch ((uintptr_t)dst) { case (uintptr_t)BDG_BCAST: case (uintptr_t)BDG_MCAST: case (uintptr_t)BDG_LOCAL: case (uintptr_t)BDG_UNKNOWN: case (uintptr_t)BDG_DROP: BDG_STAT(ifp, dst); break ; default : if (dst == ifp || dropit) BDG_STAT(ifp, BDG_DROP); else BDG_STAT(ifp, BDG_FORWARD); break ; } if ( dropit ) { if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_LOCAL) dst = BDG_LOCAL ; else dst = BDG_DROP ; } else { if (dst == ifp) dst = BDG_DROP; } DEB(printf("bridge_in %6D ->%6D ty 0x%04x dst %s%d\n", eh->ether_shost, ".", eh->ether_dhost, ".", ntohs(eh->ether_type), (dst <= BDG_FORWARD) ? bdg_dst_names[(int)dst] : dst->if_name, (dst <= BDG_FORWARD) ? 0 : dst->if_unit); ) return dst ; } /* * Forward a packet to dst -- which can be a single interface or * an entire cluster. The src port and muted interfaces are excluded. * * If src == NULL, the pkt comes from ether_output, and dst is the real * interface the packet is originally sent to. In this case, we must forward * it to the whole cluster. * We never call bdg_forward from ether_output on interfaces which are * not part of a cluster. * * If possible (i.e. we can determine that the caller does not need * a copy), the packet is consumed here, and bdg_forward returns NULL. * Otherwise, a pointer to a copy of the packet is returned. */ static struct mbuf * bdg_forward(struct mbuf *m0, struct ifnet *dst) { #define EH_RESTORE(_m) do { \ M_PREPEND((_m), ETHER_HDR_LEN, M_NOWAIT); \ if ((_m) == NULL) { \ bdg_dropped++; \ return NULL; \ } \ if (eh != mtod((_m), struct ether_header *)) \ bcopy(&save_eh, mtod((_m), struct ether_header *), ETHER_HDR_LEN); \ else \ bdg_predict++; \ } while (0); struct ether_header *eh; struct ifnet *src; struct ifnet *ifp, *last; int shared = bdg_copy ; /* someone else is using the mbuf */ int once = 0; /* loop only once */ struct ifnet *real_dst = dst ; /* real dst from ether_output */ struct ip_fw_args args; #ifdef PFIL_HOOKS struct packet_filter_hook *pfh; int rv; #endif /* PFIL_HOOKS */ struct ether_header save_eh; DEB(quad_t ticks; ticks = rdtsc();) args.rule = NULL; /* did we match a firewall rule ? */ /* Fetch state from dummynet tag, ignore others */ for (;m0->m_type == MT_TAG; m0 = m0->m_next) if (m0->_m_tag_id == PACKET_TAG_DUMMYNET) { args.rule = ((struct dn_pkt *)m0)->rule; shared = 0; /* For sure this is our own mbuf. */ } if (args.rule == NULL) bdg_thru++; /* first time through bdg_forward, count packet */ /* * The packet arrives with the Ethernet header at the front. */ eh = mtod(m0, struct ether_header *); src = m0->m_pkthdr.rcvif; if (src == NULL) /* packet from ether_output */ dst = bridge_dst_lookup(eh, ifp2sc[real_dst->if_index].cluster); if (dst == BDG_DROP) { /* this should not happen */ printf("xx bdg_forward for BDG_DROP\n"); m_freem(m0); bdg_dropped++; return NULL; } if (dst == BDG_LOCAL) { /* this should not happen as well */ printf("xx ouch, bdg_forward for local pkt\n"); return m0; } if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) { ifp = TAILQ_FIRST(&ifnet) ; /* scan all ports */ once = 0 ; if (dst != BDG_UNKNOWN) /* need a copy for the local stack */ shared = 1 ; } else { ifp = dst ; once = 1 ; } if ((uintptr_t)(ifp) <= (u_int)BDG_FORWARD) panic("bdg_forward: bad dst"); /* * Do filtering in a very similar way to what is done in ip_output. * Only if firewall is loaded, enabled, and the packet is not * from ether_output() (src==NULL, or we would filter it twice). * Additional restrictions may apply e.g. non-IP, short packets, * and pkts already gone through a pipe. */ if (src != NULL && ( #ifdef PFIL_HOOKS ((pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh)) != NULL && bdg_ipf !=0) || #endif (IPFW_LOADED && bdg_ipfw != 0))) { int i; if (args.rule != NULL && fw_one_pass) goto forward; /* packet already partially processed */ /* * i need some amt of data to be contiguous, and in case others need * the packet (shared==1) also better be in the first mbuf. */ i = min(m0->m_pkthdr.len, max_protohdr) ; if ( shared || m0->m_len < i) { m0 = m_pullup(m0, i) ; if (m0 == NULL) { printf("-- bdg: pullup failed.\n") ; bdg_dropped++; return NULL ; } eh = mtod(m0, struct ether_header *); } /* * Processing below expects the Ethernet header is stripped. * Furthermore, the mbuf chain might be replaced at various * places. To deal with this we copy the header to a temporary * location, strip the header, and restore it as needed. */ bcopy(eh, &save_eh, ETHER_HDR_LEN); /* local copy for restore */ m_adj(m0, ETHER_HDR_LEN); /* temporarily strip header */ #ifdef PFIL_HOOKS /* * NetBSD-style generic packet filter, pfil(9), hooks. * Enables ipf(8) in bridging. */ if (m0->m_pkthdr.len >= sizeof(struct ip) && ntohs(save_eh.ether_type) == ETHERTYPE_IP) { /* * before calling the firewall, swap fields the same as IP does. * here we assume the pkt is an IP one and the header is contiguous */ struct ip *ip = mtod(m0, struct ip *); ip->ip_len = ntohs(ip->ip_len); ip->ip_off = ntohs(ip->ip_off); for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) if (pfh->pfil_func) { rv = pfh->pfil_func(ip, ip->ip_hl << 2, src, 0, &m0); if (m0 == NULL) { bdg_dropped++; return NULL; } if (rv != 0) { EH_RESTORE(m0); /* restore Ethernet header */ return m0; } ip = mtod(m0, struct ip *); } /* * If we get here, the firewall has passed the pkt, but the mbuf * pointer might have changed. Restore ip and the fields ntohs()'d. */ ip = mtod(m0, struct ip *); ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); } #endif /* PFIL_HOOKS */ /* * Prepare arguments and call the firewall. */ if (!IPFW_LOADED || bdg_ipfw == 0) { EH_RESTORE(m0); /* restore Ethernet header */ goto forward; /* not using ipfw, accept the packet */ } /* * XXX The following code is very similar to the one in * if_ethersubr.c:ether_ipfw_chk() */ args.m = m0; /* the packet we are looking at */ args.oif = NULL; /* this is an input packet */ args.divert_rule = 0; /* we do not support divert yet */ args.next_hop = NULL; /* we do not support forward yet */ args.eh = &save_eh; /* MAC header for bridged/MAC packets */ i = ip_fw_chk_ptr(&args); m0 = args.m; /* in case the firewall used the mbuf */ EH_RESTORE(m0); /* restore Ethernet header */ if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */ return m0 ; if (i == 0) /* a PASS rule. */ goto forward ; if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) { /* * Pass the pkt to dummynet, which consumes it. * If shared, make a copy and keep the original. */ struct mbuf *m ; if (shared) { m = m_copypacket(m0, M_DONTWAIT); if (m == NULL) { /* copy failed, give up */ bdg_dropped++; return NULL; } } else { m = m0 ; /* pass the original to dummynet */ m0 = NULL ; /* and nothing back to the caller */ } args.oif = real_dst; ip_dn_io_ptr(m, (i & 0xffff),DN_TO_BDG_FWD, &args); return m0 ; } /* * XXX at some point, add support for divert/forward actions. * If none of the above matches, we have to drop the packet. */ bdg_ipfw_drops++ ; return m0 ; } forward: /* * Again, bring up the headers in case of shared bufs to avoid * corruptions in the future. */ if ( shared ) { int i = min(m0->m_pkthdr.len, max_protohdr) ; m0 = m_pullup(m0, i) ; if (m0 == NULL) { bdg_dropped++ ; return NULL ; } /* NB: eh is not used below; no need to recalculate it */ } /* * now real_dst is used to determine the cluster where to forward. * For packets coming from ether_input, this is the one of the 'src' * interface, whereas for locally generated packets (src==NULL) it * is the cluster of the original destination interface, which * was already saved into real_dst. */ if (src != NULL) real_dst = src ; last = NULL; for (;;) { if (last) { /* need to forward packet leftover from previous loop */ struct mbuf *m ; if (shared == 0 && once ) { /* no need to copy */ m = m0 ; m0 = NULL ; /* original is gone */ } else { m = m_copypacket(m0, M_DONTWAIT); if (m == NULL) { printf("bdg_forward: sorry, m_copypacket failed!\n"); bdg_dropped++ ; return m0 ; /* the original is still there... */ } } if (!IF_HANDOFF(&last->if_snd, m, last)) { #if 0 BDG_MUTE(last); /* should I also mute ? */ #endif } BDG_STAT(last, BDG_OUT); last = NULL ; if (once) break ; } if (ifp == NULL) break ; /* * If the interface is used for bridging, not muted, not full, * up and running, is not the source interface, and belongs to * the same cluster as the 'real_dst', then send here. */ if ( BDG_USED(ifp) && !BDG_MUTED(ifp) && !_IF_QFULL(&ifp->if_snd) && (ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING) && ifp != src && BDG_SAMECLUSTER(ifp, real_dst) ) last = ifp ; ifp = TAILQ_NEXT(ifp, if_link) ; if (ifp == NULL) once = 1 ; } DEB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ; if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; ) return m0 ; #undef EH_RESTORE } /* * initialization of bridge code. */ static int bdginit(void) { printf("BRIDGE 020214 loaded\n"); ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc), M_IFADDR, M_WAITOK | M_ZERO ); if (ifp2sc == NULL) return ENOMEM ; bridge_in_ptr = bridge_in; bdg_forward_ptr = bdg_forward; bdgtakeifaces_ptr = reconfigure_bridge; n_clusters = 0; clusters = NULL; do_bridge=0; bzero(&bdg_stats, sizeof(bdg_stats) ); bdgtakeifaces_ptr(); bdg_timeout(0); return 0 ; } /* * initialization code, both for static and dynamic loading. */ static int bridge_modevent(module_t mod, int type, void *unused) { int s; int err = 0 ; switch (type) { case MOD_LOAD: if (BDG_LOADED) { err = EEXIST; break ; } s = splimp(); err = bdginit(); splx(s); break; case MOD_UNLOAD: #if !defined(KLD_MODULE) printf("bridge statically compiled, cannot unload\n"); err = EINVAL ; #else s = splimp(); do_bridge = 0; bridge_in_ptr = NULL; bdg_forward_ptr = NULL; bdgtakeifaces_ptr = NULL; untimeout(bdg_timeout, NULL, bdg_timeout_h); bridge_off(); if (clusters) free(clusters, M_IFADDR); free(ifp2sc, M_IFADDR); ifp2sc = NULL ; splx(s); #endif break; default: err = EINVAL ; break; } return err; } static moduledata_t bridge_mod = { "bridge", bridge_modevent, 0 }; DECLARE_MODULE(bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); MODULE_VERSION(bridge, 1);