2 * Copyright (c) 1998-2002 Luigi Rizzo
4 * Work partly supported by: Cisco Systems, Inc. - NSITE lab, RTP, NC
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * This code implements bridging in FreeBSD. It only acts on ethernet
32 * interfaces, including VLANs (others are still usable for routing).
33 * A FreeBSD host can implement multiple logical bridges, called
34 * "clusters". Each cluster is made of a set of interfaces, and
35 * identified by a "cluster-id" which is a number in the range 1..2^16-1.
37 * Bridging is enabled by the sysctl variable
38 * net.link.ether.bridge.enable
39 * the grouping of interfaces into clusters is done with
40 * net.link.ether.bridge.config
41 * containing a list of interfaces each optionally followed by
42 * a colon and the cluster it belongs to (1 is the default).
43 * Separators can be spaces, commas or tabs, e.g.
44 * net.link.ether.bridge.config="fxp0:2 fxp1:2 dc0 dc1:1"
45 * Optionally bridged packets can be passed through the firewall,
46 * this is controlled by the variable
47 * net.link.ether.bridge.ipfw
49 * For each cluster there is a descriptor (cluster_softc) storing
50 * the following data structures:
51 * - a hash table with the MAC address and destination interface for each
52 * known node. The table is indexed using a hash of the source address.
53 * - an array with the MAC addresses of the interfaces used in the cluster.
55 * Input packets are tapped near the beginning of ether_input(), and
56 * analysed by bridge_in(). Depending on the result, the packet
57 * can be forwarded to one or more output interfaces using bdg_forward(),
58 * and/or sent to the upper layer (e.g. in case of multicast).
60 * Output packets are intercepted near the end of ether_output().
61 * The correct destination is selected by bridge_dst_lookup(),
62 * and then forwarding is done by bdg_forward().
64 * The arp code is also modified to let a machine answer to requests
65 * irrespective of the port the request came from.
67 * In case of loops in the bridging topology, the bridge detects this
68 * event and temporarily mutes output bridging on one of the ports.
69 * Periodically, interfaces are unmuted by bdg_timeout().
70 * Muting is only implemented as a safety measure, and also as
71 * a mechanism to support a user-space implementation of the spanning
74 * To build a bridging kernel, use the following option
76 * and then at runtime set the sysctl variable to enable bridging.
78 * Only one interface per cluster is supposed to have addresses set (but
79 * there are no substantial problems if you set addresses for none or
80 * for more than one interface).
81 * Bridging will act before routing, but nothing prevents a machine
82 * from doing both (modulo bugs in the implementation...).
85 * - bridging is incompatible with multicast routing on the same
86 * machine. There is not an easy fix to this.
87 * - be very careful when bridging VLANs
88 * - loop detection is still not very robust.
91 #include <sys/param.h>
93 #include <sys/malloc.h>
94 #include <sys/protosw.h>
95 #include <sys/systm.h>
96 #include <sys/socket.h> /* for net/if.h */
97 #include <sys/ctype.h> /* string functions */
98 #include <sys/kernel.h>
99 #include <sys/module.h>
100 #include <sys/sysctl.h>
102 #include <net/ethernet.h>
104 #include <net/if_arp.h> /* for struct arpcom */
105 #include <net/if_types.h>
106 #include <net/if_var.h>
107 #include <net/pfil.h>
109 #include <netinet/in.h>
110 #include <netinet/in_systm.h>
111 #include <netinet/in_var.h>
112 #include <netinet/ip.h>
113 #include <netinet/ip_var.h>
115 #include <net/route.h>
116 #include <netinet/ip_fw.h>
117 #include <netinet/ip_dummynet.h>
118 #include <net/bridge.h>
120 /*--------------------*/
122 #define ETHER_ADDR_COPY(_dst,_src) bcopy(_src, _dst, ETHER_ADDR_LEN)
123 #define ETHER_ADDR_EQ(_a1,_a2) (bcmp(_a1, _a2, ETHER_ADDR_LEN) == 0)
126 * For each cluster, source MAC addresses are stored into a hash
127 * table which locates the port they reside on.
129 #define HASH_SIZE 8192 /* Table size, must be a power of 2 */
131 typedef struct hash_table { /* each entry. */
133 u_char etheraddr[ETHER_ADDR_LEN];
134 u_int16_t used; /* also, padding */
138 * The hash function applied to MAC addresses. Out of the 6 bytes,
139 * the last ones tend to vary more. Since we are on a little endian machine,
140 * we have to do some gimmick...
142 #define HASH_FN(addr) ( \
143 ntohs( ((u_int16_t *)addr)[1] ^ ((u_int16_t *)addr)[2] ) & (HASH_SIZE -1))
146 * This is the data structure where local addresses are stored.
149 u_char etheraddr[ETHER_ADDR_LEN];
154 * The configuration of each cluster includes the cluster id, a pointer to
155 * the hash table, and an array of local MAC addresses (of size "ports").
157 struct cluster_softc {
158 u_int16_t cluster_id;
161 struct bdg_addr *my_macs; /* local MAC addresses */
165 extern struct protosw inetsw[]; /* from netinet/ip_input.c */
167 static int n_clusters; /* number of clusters */
168 static struct cluster_softc *clusters;
170 static struct mtx bdg_mtx;
171 #define BDG_LOCK_INIT() mtx_init(&bdg_mtx, "bridge", NULL, MTX_DEF)
172 #define BDG_LOCK_DESTROY() mtx_destroy(&bdg_mtx)
173 #define BDG_LOCK() mtx_lock(&bdg_mtx)
174 #define BDG_UNLOCK() mtx_unlock(&bdg_mtx)
175 #define BDG_LOCK_ASSERT() mtx_assert(&bdg_mtx, MA_OWNED)
177 #define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
178 #define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
179 #define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster)
181 #define BDG_SAMECLUSTER(ifp,src) \
182 (src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) )
185 #define BDG_MATCH(a,b) ( \
186 ((u_int16_t *)(a))[2] == ((u_int16_t *)(b))[2] && \
187 *((u_int32_t *)(a)) == *((u_int32_t *)(b)) )
188 #define IS_ETHER_BROADCAST(a) ( \
189 *((u_int32_t *)(a)) == 0xffffffff && \
190 ((u_int16_t *)(a))[2] == 0xffff )
192 /* for machines that do not support unaligned access */
193 #define BDG_MATCH(a,b) ETHER_ADDR_EQ(a,b)
194 #define IS_ETHER_BROADCAST(a) ETHER_ADDR_EQ(a,"\377\377\377\377\377\377")
197 SYSCTL_DECL(_net_link_ether);
198 SYSCTL_NODE(_net_link_ether, OID_AUTO, bridge, CTLFLAG_RD, 0,
199 "Bridge parameters");
200 static char bridge_version[] = "031224";
201 SYSCTL_STRING(_net_link_ether_bridge, OID_AUTO, version, CTLFLAG_RD,
202 bridge_version, 0, "software version");
206 int bridge_debug = 0;
207 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, debug, CTLFLAG_RW, &bridge_debug,
208 0, "control debugging printfs");
209 #define DPRINTF(X) if (bridge_debug) printf X
216 * For timing-related debugging, you can use the following macros.
217 * remember, rdtsc() only works on Pentium-class machines
220 DDB(ticks = rdtsc();)
221 ... interesting code ...
222 DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;)
228 static int bdg_fw_avg;
229 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_avg, CTLFLAG_RW,
230 &bdg_fw_avg, 0,"Cycle counter avg");
231 static int bdg_fw_ticks;
232 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_ticks, CTLFLAG_RW,
233 &bdg_fw_ticks, 0,"Cycle counter item");
234 static int bdg_fw_count;
235 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_count, CTLFLAG_RW,
236 &bdg_fw_count, 0,"Cycle counter count");
241 static int bdginit(void);
242 static void parse_bdg_cfg(void);
243 static struct mbuf *bdg_forward(struct mbuf *, struct ifnet *);
245 static int bdg_ipf; /* IPFilter enabled in bridge */
246 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipf, CTLFLAG_RW,
247 &bdg_ipf, 0,"Pass bridged pkts through IPFilter");
249 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw, CTLFLAG_RW,
250 &bdg_ipfw,0,"Pass bridged pkts through firewall");
253 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, copy, CTLFLAG_RW,
254 &bdg_copy, 0, "Force packet copy in bdg_forward");
257 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw_drop,
258 CTLFLAG_RW, &bdg_ipfw_drops,0,"");
260 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw_collisions,
261 CTLFLAG_RW, &bdg_ipfw_colls,0,"");
264 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, packets, CTLFLAG_RW,
265 &bdg_thru, 0, "Packets through bridge");
266 static int bdg_dropped;
267 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, dropped, CTLFLAG_RW,
268 &bdg_dropped, 0, "Packets dropped in bdg_forward");
269 static int bdg_predict;
270 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, predict, CTLFLAG_RW,
271 &bdg_predict, 0, "Correctly predicted header location");
274 static char *bdg_dst_names[] = {
284 #endif /* BRIDGE_DEBUG */
287 * System initialization
289 static struct bdg_stats bdg_stats ;
290 SYSCTL_STRUCT(_net_link_ether_bridge, OID_AUTO, stats, CTLFLAG_RD,
291 &bdg_stats, bdg_stats, "bridge statistics");
293 static struct callout bdg_callout;
296 * Add an interface to a cluster, possibly creating a new entry in
297 * the cluster table. This requires reallocation of the table and
298 * updating pointers in ifp2sc.
300 static struct cluster_softc *
301 add_cluster(u_int16_t cluster_id, struct ifnet *ifp)
303 struct cluster_softc *c = NULL;
308 for (i = 0; i < n_clusters ; i++)
309 if (clusters[i].cluster_id == cluster_id)
312 /* Not found, need to reallocate */
313 c = malloc((1+n_clusters) * sizeof (*c), M_IFADDR, M_NOWAIT | M_ZERO);
314 if (c == NULL) {/* malloc failure */
315 printf("-- bridge: cannot add new cluster\n");
318 c[n_clusters].ht = (struct hash_table *)
319 malloc(HASH_SIZE * sizeof(struct hash_table),
320 M_IFADDR, M_NOWAIT | M_ZERO);
321 if (c[n_clusters].ht == NULL) {
322 printf("-- bridge: cannot allocate hash table for new cluster\n");
325 c[n_clusters].my_macs = (struct bdg_addr *)
326 malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr),
327 M_IFADDR, M_NOWAIT | M_ZERO);
328 if (c[n_clusters].my_macs == NULL) {
329 printf("-- bridge: cannot allocate mac addr table for new cluster\n");
330 free(c[n_clusters].ht, M_IFADDR);
334 c[n_clusters].cluster_id = cluster_id;
335 c[n_clusters].ports = 0;
337 * now copy old descriptors here
339 if (n_clusters > 0) {
340 for (i=0; i < n_clusters; i++)
343 * and finally update pointers in ifp2sc
345 for (i = 0 ; i < if_index && i < BDG_MAX_PORTS; i++)
346 if (ifp2sc[i].cluster != NULL)
347 ifp2sc[i].cluster = c + (ifp2sc[i].cluster - clusters);
348 free(clusters, M_IFADDR);
351 i = n_clusters; /* index of cluster entry */
354 c = clusters + i; /* the right cluster ... */
355 ETHER_ADDR_COPY(c->my_macs[c->ports].etheraddr, IFP2AC(ifp)->ac_enaddr);
366 * Turn off bridging, by clearing promisc mode on the interface,
367 * marking the interface as unused, and clearing the name in the
369 * Also dispose the hash tables associated with the clusters.
379 DPRINTF(("%s: n_clusters %d\n", __func__, n_clusters));
382 TAILQ_FOREACH(ifp, &ifnet, if_link) {
385 if (ifp->if_index >= BDG_MAX_PORTS)
386 continue; /* make sure we do not go beyond the end */
387 b = &ifp2sc[ifp->if_index];
389 if ( b->flags & IFF_BDG_PROMISC ) {
391 b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
392 DPRINTF(("%s: %s promisc OFF if_flags 0x%x "
393 "bdg_flags 0x%x\n", __func__, ifp->if_xname,
394 ifp->if_flags, b->flags));
396 b->flags &= ~(IFF_USED) ;
398 bdg_stats.s[ifp->if_index].name[0] = '\0';
403 for (i=0; i < n_clusters; i++) {
404 free(clusters[i].ht, M_IFADDR);
405 free(clusters[i].my_macs, M_IFADDR);
407 if (clusters != NULL)
408 free(clusters, M_IFADDR);
414 * set promisc mode on the interfaces we use.
424 TAILQ_FOREACH(ifp, &ifnet, if_link) {
425 struct bdg_softc *b = &ifp2sc[ifp->if_index];
427 if ( !(b->flags & IFF_USED) )
429 if ( !( ifp->if_flags & IFF_UP) ) {
432 if ( !(b->flags & IFF_BDG_PROMISC) ) {
433 (void) ifpromisc(ifp, 1);
434 b->flags |= IFF_BDG_PROMISC ;
435 DPRINTF(("%s: %s promisc ON if_flags 0x%x bdg_flags 0x%x\n",
436 __func__, ifp->if_xname, ifp->if_flags, b->flags));
438 if (b->flags & IFF_MUTE) {
439 DPRINTF(("%s: unmuting %s\n", __func__, ifp->if_xname));
440 b->flags &= ~IFF_MUTE;
446 static char bridge_cfg[1024]; /* NB: in BSS so initialized to zero */
449 * reconfigure bridge.
450 * This is also done every time we attach or detach an interface.
451 * Main use is to make sure that we do not bridge on some old
452 * (ejected) device. So, it would be really useful to have a
453 * pointer to the modified device as an argument. Without it, we
454 * have to scan all interfaces.
457 reconfigure_bridge_locked(void)
463 if (if_index >= BDG_MAX_PORTS) {
464 printf("-- sorry too many interfaces (%d, max is %d),"
465 " disabling bridging\n", if_index, BDG_MAX_PORTS);
475 reconfigure_bridge(void)
478 reconfigure_bridge_locked();
483 * parse the config string, set IFF_USED, name and cluster_id
484 * for all interfaces found.
485 * The config string is a list of "if[:cluster]" with
486 * a number of possible separators (see "sep"). In particular the
487 * use of the space lets you set bridge_cfg with the output from
495 static const char *sep = ", \t";
499 for (p = bridge_cfg; *p ; p++) {
504 if (index(sep, *p)) /* skip separators */
506 /* names are lowercase and digits */
507 for ( beg = p ; islower(*p) || isdigit(*p) ; p++ )
509 l = p - beg ; /* length of name string */
510 if (l == 0) /* invalid name */
512 if ( *p != ':' ) /* no ':', assume default cluster 1 */
514 else /* fetch cluster */
515 cluster = strtoul( p+1, &p, 10);
519 * now search in interface list for a matching name
521 IFNET_RLOCK(); /* could sleep XXX */
522 TAILQ_FOREACH(ifp, &ifnet, if_link) {
524 if (!strncmp(beg, ifp->if_xname, max(l, strlen(ifp->if_xname)))) {
525 struct bdg_softc *b = &ifp2sc[ifp->if_index];
526 if (ifp->if_type != IFT_ETHER && ifp->if_type != IFT_L2VLAN) {
527 printf("%s is not an ethernet, continue\n", ifp->if_xname);
530 if (b->flags & IFF_USED) {
531 printf("%s already used, skipping\n", ifp->if_xname);
534 b->cluster = add_cluster(htons(cluster), ifp);
535 b->flags |= IFF_USED ;
536 snprintf(bdg_stats.s[ifp->if_index].name,
537 sizeof(bdg_stats.s[ifp->if_index].name),
538 "%s:%d", ifp->if_xname, cluster);
540 DPRINTF(("%s: found %s next c %d\n", __func__,
541 bdg_stats.s[ifp->if_index].name, c));
548 printf("interface %s Not found in bridge\n", beg);
556 * handler for net.link.ether.bridge
559 sysctl_bdg(SYSCTL_HANDLER_ARGS)
561 int enable = do_bridge;
564 error = sysctl_handle_int(oidp, &enable, 0, req);
565 enable = (enable) ? 1 : 0;
567 if (enable != do_bridge) {
569 reconfigure_bridge_locked();
574 SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, enable, CTLTYPE_INT|CTLFLAG_RW,
575 &do_bridge, 0, &sysctl_bdg, "I", "Bridging");
578 * handler for net.link.ether.bridge_cfg
581 sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
586 new_cfg = malloc(sizeof(bridge_cfg), M_TEMP, M_WAITOK);
587 bcopy(bridge_cfg, new_cfg, sizeof(bridge_cfg));
589 error = sysctl_handle_string(oidp, new_cfg, oidp->oid_arg2, req);
592 if (strcmp(new_cfg, bridge_cfg)) {
593 bcopy(new_cfg, bridge_cfg, sizeof(bridge_cfg));
594 reconfigure_bridge_locked();
599 free(new_cfg, M_TEMP);
603 SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, config, CTLTYPE_STRING|CTLFLAG_RW,
604 &bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
605 "Bridge configuration");
608 sysctl_refresh(SYSCTL_HANDLER_ARGS)
611 reconfigure_bridge();
615 SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, refresh, CTLTYPE_INT|CTLFLAG_WR,
616 NULL, 0, &sysctl_refresh, "I", "iface refresh");
619 #define SYSCTL_OID_COMPAT(parent, nbr, name, kind, a1, a2, handler, fmt, descr)\
620 static struct sysctl_oid sysctl__##parent##_##name##_compat = { \
621 &sysctl_##parent##_children, { 0 }, \
622 nbr, kind, a1, a2, #name, handler, fmt, 0, descr }; \
623 DATA_SET(sysctl_set, sysctl__##parent##_##name##_compat)
624 #define SYSCTL_INT_COMPAT(parent, nbr, name, access, ptr, val, descr) \
625 SYSCTL_OID_COMPAT(parent, nbr, name, CTLTYPE_INT|(access), \
626 ptr, val, sysctl_handle_int, "I", descr)
627 #define SYSCTL_STRUCT_COMPAT(parent, nbr, name, access, ptr, type, descr)\
628 SYSCTL_OID_COMPAT(parent, nbr, name, CTLTYPE_OPAQUE|(access), \
629 ptr, sizeof(struct type), sysctl_handle_opaque, \
631 #define SYSCTL_PROC_COMPAT(parent, nbr, name, access, ptr, arg, handler, fmt, descr) \
632 SYSCTL_OID_COMPAT(parent, nbr, name, (access), \
633 ptr, arg, handler, fmt, descr)
635 SYSCTL_INT_COMPAT(_net_link_ether, OID_AUTO, bridge_ipf, CTLFLAG_RW,
636 &bdg_ipf, 0,"Pass bridged pkts through IPFilter");
637 SYSCTL_INT_COMPAT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
638 &bdg_ipfw,0,"Pass bridged pkts through firewall");
639 SYSCTL_STRUCT_COMPAT(_net_link_ether, PF_BDG, bdgstats, CTLFLAG_RD,
640 &bdg_stats, bdg_stats, "bridge statistics");
641 SYSCTL_PROC_COMPAT(_net_link_ether, OID_AUTO, bridge_cfg,
642 CTLTYPE_STRING|CTLFLAG_RW,
643 &bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
644 "Bridge configuration");
645 SYSCTL_PROC_COMPAT(_net_link_ether, OID_AUTO, bridge_refresh,
646 CTLTYPE_INT|CTLFLAG_WR,
647 NULL, 0, &sysctl_refresh, "I", "iface refresh");
650 static int bdg_loops;
651 static int bdg_slowtimer = 0;
652 static int bdg_age_index = 0; /* index of table position to age */
655 * called periodically to flush entries etc.
658 bdg_timeout(void *dummy)
665 * age entries in the forwarding table.
667 l = bdg_age_index + HASH_SIZE/4 ;
671 for (i = 0; i < n_clusters; i++) {
672 bdg_hash_table *bdg_table = clusters[i].ht;
673 for (; bdg_age_index < l; bdg_age_index++)
674 if (bdg_table[bdg_age_index].used)
675 bdg_table[bdg_age_index].used = 0;
676 else if (bdg_table[bdg_age_index].name) {
677 DPRINTF(("%s: flushing stale entry %d\n",
678 __func__, bdg_age_index));
679 bdg_table[bdg_age_index].name = NULL;
682 if (bdg_age_index >= HASH_SIZE)
685 if (--bdg_slowtimer <= 0 ) {
688 bridge_on(); /* we just need unmute, really */
693 callout_reset(&bdg_callout, 2*hz, bdg_timeout, NULL);
697 * Find the right pkt destination:
698 * BDG_BCAST is a broadcast
699 * BDG_MCAST is a multicast
700 * BDG_LOCAL is for a local address
701 * BDG_DROP must be dropped
702 * other ifp of the dest. interface (incl.self)
704 * We assume this is only called for interfaces for which bridging
705 * is enabled, i.e. BDG_USED(ifp) is true.
707 static __inline struct ifnet *
708 bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c)
710 bdg_hash_table *bt; /* pointer to entry in hash table */
714 if (ETHER_IS_MULTICAST(eh->ether_dhost))
715 return IS_ETHER_BROADCAST(eh->ether_dhost) ? BDG_BCAST : BDG_MCAST;
717 * Lookup local addresses in case one matches. We optimize
718 * for the common case of two interfaces.
720 KASSERT(c->ports != 0, ("lookup with no ports!"));
724 for (i = c->ports-1; i > 1; i--) {
725 if (ETHER_ADDR_EQ(c->my_macs[i].etheraddr, eh->ether_dhost))
730 if (ETHER_ADDR_EQ(c->my_macs[1].etheraddr, eh->ether_dhost))
733 if (ETHER_ADDR_EQ(c->my_macs[0].etheraddr, eh->ether_dhost))
737 * Look for a possible destination in table
739 bt = &c->ht[HASH_FN(eh->ether_dhost)];
740 if (bt->name && ETHER_ADDR_EQ(bt->etheraddr, eh->ether_dhost))
747 * bridge_in() is invoked to perform bridging decision on input packets.
750 * eh Ethernet header of the incoming packet.
751 * ifp interface the packet is coming from.
753 * On Return: destination of packet, one of
754 * BDG_BCAST broadcast
755 * BDG_MCAST multicast
756 * BDG_LOCAL is only for a local address (do not forward)
757 * BDG_DROP drop the packet
758 * ifp ifp of the destination interface.
760 * Forwarding is not done directly to give a chance to some drivers
761 * to fetch more of the packet, or simply drop it completely.
765 bridge_in(struct ifnet *ifp, struct mbuf *m)
767 struct ether_header *eh;
768 struct ifnet *dst, *old;
769 bdg_hash_table *bt; /* location in hash table */
770 int dropit = BDG_MUTED(ifp);
773 eh = mtod(m, struct ether_header *);
776 * hash the source address
779 index = HASH_FN(eh->ether_shost);
780 bt = &BDG_CLUSTER(ifp)->ht[index];
783 if (old) { /* the entry is valid */
784 if (!ETHER_ADDR_EQ(eh->ether_shost, bt->etheraddr)) {
786 bt->name = NULL; /* NB: will overwrite below */
787 } else if (old != ifp) {
789 * Found a loop. Either a machine has moved, or there
790 * is a misconfiguration/reconfiguration of the network.
791 * First, do not forward this packet!
792 * Record the relocation anyways; then, if loops persist,
793 * suspect a reconfiguration and disable forwarding
794 * from the old interface.
796 bt->name = ifp; /* relocate address */
797 printf("-- loop (%d) %6D to %s from %s (%s)\n",
798 bdg_loops, eh->ether_shost, ".",
799 ifp->if_xname, old->if_xname,
800 BDG_MUTED(old) ? "muted":"active");
802 if (!BDG_MUTED(old)) {
803 if (bdg_loops++ > 10)
810 * now write the source address into the table
812 if (bt->name == NULL) {
813 DPRINTF(("%s: new addr %6D at %d for %s\n",
814 __func__, eh->ether_shost, ".", index, ifp->if_xname));
815 ETHER_ADDR_COPY(bt->etheraddr, eh->ether_shost);
818 dst = bridge_dst_lookup(eh, BDG_CLUSTER(ifp));
822 * bridge_dst_lookup can return the following values:
823 * BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp.
824 * For muted interfaces, or when we detect a loop, the first 3 are
825 * changed in BDG_LOCAL (we still listen to incoming traffic),
826 * and others to BDG_DROP (no use for the local host).
827 * Also, for incoming packets, ifp is changed to BDG_DROP if ifp == src.
828 * These changes are not necessary for outgoing packets from ether_output().
830 BDG_STAT(ifp, BDG_IN);
831 switch ((uintptr_t)dst) {
832 case (uintptr_t)BDG_BCAST:
833 case (uintptr_t)BDG_MCAST:
834 case (uintptr_t)BDG_LOCAL:
835 case (uintptr_t)BDG_UNKNOWN:
836 case (uintptr_t)BDG_DROP:
840 if (dst == ifp || dropit)
841 BDG_STAT(ifp, BDG_DROP);
843 BDG_STAT(ifp, BDG_FORWARD);
848 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_LOCAL)
856 DPRINTF(("%s: %6D ->%6D ty 0x%04x dst %s\n", __func__,
857 eh->ether_shost, ".",
858 eh->ether_dhost, ".",
859 ntohs(eh->ether_type),
860 (dst <= BDG_FORWARD) ? bdg_dst_names[(uintptr_t)dst] :
863 switch ((uintptr_t)dst) {
864 case (uintptr_t)BDG_DROP:
867 case (uintptr_t)BDG_LOCAL:
869 case (uintptr_t)BDG_BCAST:
870 case (uintptr_t)BDG_MCAST:
871 m = bdg_forward(m, dst);
872 #ifdef DIAGNOSTIC /* glebius: am I right here? */
874 if_printf(ifp, "bridge dropped %s packet\n",
875 dst == BDG_BCAST ? "broadcast" : "multicast");
881 m = bdg_forward(m, dst);
884 return (NULL); /* not reached */
888 * Return 1 if it's ok to send a packet out the specified interface.
889 * The interface must be:
894 * not the source interface, and
895 * belong to the same cluster as the 'real_dst'.
898 bridge_ifok(struct ifnet *ifp, struct ifnet *src, struct ifnet *dst)
900 return (BDG_USED(ifp)
902 && !_IF_QFULL(&ifp->if_snd)
903 && (ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING)
905 && BDG_SAMECLUSTER(ifp, dst));
909 * Forward a packet to dst -- which can be a single interface or
910 * an entire cluster. The src port and muted interfaces are excluded.
912 * If src == NULL, the pkt comes from ether_output, and dst is the real
913 * interface the packet is originally sent to. In this case, we must forward
914 * it to the whole cluster.
915 * We never call bdg_forward from ether_output on interfaces which are
916 * not part of a cluster.
918 * If possible (i.e. we can determine that the caller does not need
919 * a copy), the packet is consumed here, and bdg_forward returns NULL.
920 * Otherwise, a pointer to a copy of the packet is returned.
923 bdg_forward(struct mbuf *m0, struct ifnet *dst)
925 #define EH_RESTORE(_m) do { \
926 M_PREPEND((_m), ETHER_HDR_LEN, M_DONTWAIT); \
927 if ((_m) == NULL) { \
931 if (eh != mtod((_m), struct ether_header *)) \
932 bcopy(&save_eh, mtod((_m), struct ether_header *), ETHER_HDR_LEN); \
936 struct ether_header *eh;
938 struct ifnet *ifp, *last;
939 int shared = bdg_copy; /* someone else is using the mbuf */
941 struct ifnet *real_dst = dst; /* real dst from ether_output */
942 struct ip_fw_args args;
943 struct ether_header save_eh;
946 DDB(quad_t ticks; ticks = rdtsc();)
948 args.rule = ip_dn_claim_rule(m0);
950 shared = 0; /* For sure this is our own mbuf. */
952 bdg_thru++; /* count 1st time through bdg_forward */
955 * The packet arrives with the Ethernet header at the front.
957 eh = mtod(m0, struct ether_header *);
959 src = m0->m_pkthdr.rcvif;
960 if (src == NULL) { /* packet from ether_output */
962 dst = bridge_dst_lookup(eh, BDG_CLUSTER(real_dst));
966 if (dst == BDG_DROP) { /* this should not happen */
967 printf("xx bdg_forward for BDG_DROP\n");
972 if (dst == BDG_LOCAL) { /* this should not happen as well */
973 printf("xx ouch, bdg_forward for local pkt\n");
976 if (dst == BDG_BCAST || dst == BDG_MCAST) {
977 /* need a copy for the local stack */
982 * Do filtering in a very similar way to what is done in ip_output.
983 * Only if firewall is loaded, enabled, and the packet is not
984 * from ether_output() (src==NULL, or we would filter it twice).
985 * Additional restrictions may apply e.g. non-IP, short packets,
986 * and pkts already gone through a pipe.
989 (inet_pfil_hook.ph_busy_count >= 0 && bdg_ipf != 0) ||
990 (IPFW_LOADED && bdg_ipfw != 0))) {
994 if (args.rule != NULL && fw_one_pass)
995 goto forward; /* packet already partially processed */
997 * i need some amt of data to be contiguous, and in case others need
998 * the packet (shared==1) also better be in the first mbuf.
1000 i = min(m0->m_pkthdr.len, max_protohdr) ;
1001 if (shared || m0->m_len < i) {
1002 m0 = m_pullup(m0, i);
1004 printf("%s: m_pullup failed\n", __func__); /* XXXDPRINTF*/
1008 eh = mtod(m0, struct ether_header *);
1012 * Processing below expects the Ethernet header is stripped.
1013 * Furthermore, the mbuf chain might be replaced at various
1014 * places. To deal with this we copy the header to a temporary
1015 * location, strip the header, and restore it as needed.
1017 bcopy(eh, &save_eh, ETHER_HDR_LEN); /* local copy for restore */
1018 m_adj(m0, ETHER_HDR_LEN); /* temporarily strip header */
1021 * NetBSD-style generic packet filter, pfil(9), hooks.
1022 * Enables ipf(8) in bridging.
1024 if (!IPFW_LOADED) { /* XXX: Prevent ipfw from being run twice. */
1025 if (inet_pfil_hook.ph_busy_count >= 0 &&
1026 m0->m_pkthdr.len >= sizeof(struct ip) &&
1027 ntohs(save_eh.ether_type) == ETHERTYPE_IP) {
1029 * before calling the firewall, swap fields the same as IP does.
1030 * here we assume the pkt is an IP one and the header is contiguous
1032 struct ip *ip = mtod(m0, struct ip *);
1034 ip->ip_len = ntohs(ip->ip_len);
1035 ip->ip_off = ntohs(ip->ip_off);
1037 if (pfil_run_hooks(&inet_pfil_hook, &m0, src, PFIL_IN, NULL) != 0) {
1038 /* NB: hook should consume packet */
1041 if (m0 == NULL) /* consumed by filter */
1044 * If we get here, the firewall has passed the pkt, but the mbuf
1045 * pointer might have changed. Restore ip and the fields ntohs()'d.
1047 ip = mtod(m0, struct ip *);
1048 ip->ip_len = htons(ip->ip_len);
1049 ip->ip_off = htons(ip->ip_off);
1051 } /* XXX: Prevent ipfw from being run twice. */
1054 * Prepare arguments and call the firewall.
1056 if (!IPFW_LOADED || bdg_ipfw == 0) {
1057 EH_RESTORE(m0); /* restore Ethernet header */
1058 goto forward; /* not using ipfw, accept the packet */
1062 * XXX The following code is very similar to the one in
1063 * if_ethersubr.c:ether_ipfw_chk()
1066 args.m = m0; /* the packet we are looking at */
1067 args.oif = NULL; /* this is an input packet */
1068 args.next_hop = NULL; /* we do not support forward yet */
1069 args.eh = &save_eh; /* MAC header for bridged/MAC packets */
1070 i = ip_fw_chk_ptr(&args);
1071 m0 = args.m; /* in case the firewall used the mbuf */
1074 EH_RESTORE(m0); /* restore Ethernet header */
1076 if (i == IP_FW_DENY) /* drop */
1079 KASSERT(m0 != NULL, ("bdg_forward: m0 is NULL"));
1081 if (i == 0) /* a PASS rule. */
1083 if (DUMMYNET_LOADED && (i == IP_FW_DUMMYNET)) {
1085 * Pass the pkt to dummynet, which consumes it.
1086 * If shared, make a copy and keep the original.
1089 m = m_copypacket(m0, M_DONTWAIT);
1090 if (m == NULL) { /* copy failed, give up */
1095 m = m0 ; /* pass the original to dummynet */
1096 m0 = NULL ; /* and nothing back to the caller */
1099 args.oif = real_dst;
1100 ip_dn_io_ptr(m, DN_TO_BDG_FWD, &args);
1104 * XXX at some point, add support for divert/forward actions.
1105 * If none of the above matches, we have to drop the packet.
1112 * Again, bring up the headers in case of shared bufs to avoid
1113 * corruptions in the future.
1116 int i = min(m0->m_pkthdr.len, max_protohdr);
1118 m0 = m_pullup(m0, i);
1123 /* NB: eh is not used below; no need to recalculate it */
1127 * now real_dst is used to determine the cluster where to forward.
1128 * For packets coming from ether_input, this is the one of the 'src'
1129 * interface, whereas for locally generated packets (src==NULL) it
1130 * is the cluster of the original destination interface, which
1131 * was already saved into real_dst.
1137 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
1139 * Scan all ports and send copies to all but the last.
1141 IFNET_RLOCK(); /* XXX replace with generation # */
1142 TAILQ_FOREACH(ifp, &ifnet, if_link) {
1143 if (bridge_ifok(ifp, src, real_dst)) {
1146 * At this point we know two interfaces need a copy
1147 * of the packet (last + ifp) so we must create a
1148 * copy to handoff to last.
1150 m = m_copypacket(m0, M_DONTWAIT);
1153 printf("%s: , m_copypacket failed!\n", __func__);
1155 return m0; /* the original is still there... */
1157 IFQ_HANDOFF(last, m, error);
1159 BDG_STAT(last, BDG_OUT);
1168 if (bridge_ifok(dst, src, real_dst))
1172 if (shared) { /* need to copy */
1173 m = m_copypacket(m0, M_DONTWAIT);
1175 printf("%s: sorry, m_copypacket failed!\n", __func__);
1177 return m0; /* the original is still there... */
1179 } else { /* consume original */
1182 IFQ_HANDOFF(last, m, error);
1184 BDG_STAT(last, BDG_OUT);
1189 DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;
1190 if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; )
1196 * initialization of bridge code.
1202 printf("BRIDGE %s loaded\n", bridge_version);
1204 ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
1205 M_IFADDR, M_WAITOK | M_ZERO );
1215 bzero(&bdg_stats, sizeof(bdg_stats));
1217 bridge_in_ptr = bridge_in;
1218 bdg_forward_ptr = bdg_forward;
1219 bdgtakeifaces_ptr = reconfigure_bridge;
1221 bdgtakeifaces_ptr(); /* XXX does this do anything? */
1223 callout_init(&bdg_callout, NET_CALLOUT_MPSAFE);
1231 bridge_in_ptr = NULL;
1232 bdg_forward_ptr = NULL;
1233 bdgtakeifaces_ptr = NULL;
1235 callout_stop(&bdg_callout);
1240 free(ifp2sc, M_IFADDR);
1247 * initialization code, both for static and dynamic loading.
1250 bridge_modevent(module_t mod, int type, void *unused)
1273 static moduledata_t bridge_mod = {
1279 DECLARE_MODULE(bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
1280 MODULE_VERSION(bridge, 1);