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
27 * $FreeBSD: src/sys/net/bridge.c,v 1.16.2.25 2003/01/23 21:06:44 sam Exp $
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
39 * the grouping of interfaces into clusters is done with
40 * net.link.ether.bridge_cfg
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_cfg="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/systm.h>
95 #include <sys/socket.h> /* for net/if.h */
96 #include <sys/ctype.h> /* string functions */
97 #include <sys/kernel.h>
98 #include <sys/sysctl.h>
101 #include <net/if_types.h>
102 #include <net/if_var.h>
104 #include <netinet/in.h> /* for struct arpcom */
105 #include <netinet/in_systm.h>
106 #include <netinet/in_var.h>
107 #include <netinet/ip.h>
108 #include <netinet/if_ether.h> /* for struct arpcom */
110 #include <net/route.h>
111 #include <netinet/ip_fw.h>
112 #include <netinet/ip_dummynet.h>
113 #include <net/bridge.h>
115 /*--------------------*/
118 * For each cluster, source MAC addresses are stored into a hash
119 * table which locates the port they reside on.
121 #define HASH_SIZE 8192 /* Table size, must be a power of 2 */
123 typedef struct hash_table { /* each entry. */
126 u_int16_t used; /* also, padding */
130 * The hash function applied to MAC addresses. Out of the 6 bytes,
131 * the last ones tend to vary more. Since we are on a little endian machine,
132 * we have to do some gimmick...
134 #define HASH_FN(addr) ( \
135 ntohs( ((u_int16_t *)addr)[1] ^ ((u_int16_t *)addr)[2] ) & (HASH_SIZE -1))
138 * This is the data structure where local addresses are stored.
141 u_char etheraddr[6] ;
146 * The configuration of each cluster includes the cluster id, a pointer to
147 * the hash table, and an array of local MAC addresses (of size "ports").
149 struct cluster_softc {
150 u_int16_t cluster_id;
153 struct bdg_addr *my_macs; /* local MAC addresses */
157 extern struct protosw inetsw[]; /* from netinet/ip_input.c */
158 extern u_char ip_protox[]; /* from netinet/ip_input.c */
160 static int n_clusters; /* number of clusters */
161 static struct cluster_softc *clusters;
163 #define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
164 #define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
165 #define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster)
167 #define BDG_SAMECLUSTER(ifp,src) \
168 (src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) )
171 #define BDG_MATCH(a,b) ( \
172 ((u_int16_t *)(a))[2] == ((u_int16_t *)(b))[2] && \
173 *((u_int32_t *)(a)) == *((u_int32_t *)(b)) )
174 #define IS_ETHER_BROADCAST(a) ( \
175 *((u_int32_t *)(a)) == 0xffffffff && \
176 ((u_int16_t *)(a))[2] == 0xffff )
178 /* for machines that do not support unaligned access */
179 #define BDG_MATCH(a,b) (!bcmp(a, b, ETHER_ADDR_LEN) )
180 #define IS_ETHER_BROADCAST(a) (!bcmp(a, "\377\377\377\377\377\377", 6))
185 * For timing-related debugging, you can use the following macros.
186 * remember, rdtsc() only works on Pentium-class machines
189 DDB(ticks = rdtsc();)
190 ... interesting code ...
191 DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;)
199 static int bdginit(void);
200 static void parse_bdg_cfg(void);
202 static int bdg_ipf; /* IPFilter enabled in bridge */
206 * For IPFilter, declared in ip_input.c
208 extern int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **);
210 #if 0 /* debugging only */
211 static char *bdg_dst_names[] = {
223 * System initialization
226 static struct bdg_stats bdg_stats ;
227 static struct callout_handle bdg_timeout_h ;
230 * Add an interface to a cluster, possibly creating a new entry in
231 * the cluster table. This requires reallocation of the table and
232 * updating pointers in ifp2sc.
234 static struct cluster_softc *
235 add_cluster(u_int16_t cluster_id, struct arpcom *ac)
237 struct cluster_softc *c = NULL;
240 for (i = 0; i < n_clusters ; i++)
241 if (clusters[i].cluster_id == cluster_id)
244 /* Not found, need to reallocate */
245 c = malloc((1+n_clusters) * sizeof (*c), M_IFADDR, M_DONTWAIT | M_ZERO);
246 if (c == NULL) {/* malloc failure */
247 printf("-- bridge: cannot add new cluster\n");
250 c[n_clusters].ht = (struct hash_table *)
251 malloc(HASH_SIZE * sizeof(struct hash_table),
252 M_IFADDR, M_WAITOK | M_ZERO);
253 if (c[n_clusters].ht == NULL) {
254 printf("-- bridge: cannot allocate hash table for new cluster\n");
258 c[n_clusters].my_macs = (struct bdg_addr *)
259 malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr),
260 M_IFADDR, M_WAITOK | M_ZERO);
261 if (c[n_clusters].my_macs == NULL) {
262 printf("-- bridge: cannot allocate mac addr table for new cluster\n");
263 free(c[n_clusters].ht, M_IFADDR);
268 c[n_clusters].cluster_id = cluster_id;
269 c[n_clusters].ports = 0;
271 * now copy old descriptors here
273 if (n_clusters > 0) {
274 for (i=0; i < n_clusters; i++)
277 * and finally update pointers in ifp2sc
279 for (i = 0 ; i < if_index && i < BDG_MAX_PORTS; i++)
280 if (ifp2sc[i].cluster != NULL)
281 ifp2sc[i].cluster = c + (ifp2sc[i].cluster - clusters);
282 free(clusters, M_IFADDR);
285 i = n_clusters; /* index of cluster entry */
288 c = clusters + i; /* the right cluster ... */
289 bcopy(ac->ac_enaddr, &(c->my_macs[c->ports]), 6);
296 * Turn off bridging, by clearing promisc mode on the interface,
297 * marking the interface as unused, and clearing the name in the
299 * Also dispose the hash tables associated with the clusters.
307 DEB(printf("bridge_off: n_clusters %d\n", n_clusters);)
308 TAILQ_FOREACH(ifp, &ifnet, if_link) {
311 if (ifp->if_index >= BDG_MAX_PORTS)
312 continue; /* make sure we do not go beyond the end */
313 b = &(ifp2sc[ifp->if_index]);
315 if ( b->flags & IFF_BDG_PROMISC ) {
319 b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
320 DEB(printf(">> now %s%d promisc OFF if_flags 0x%x bdg_flags 0x%x\n",
321 ifp->if_name, ifp->if_unit,
322 ifp->if_flags, b->flags);)
324 b->flags &= ~(IFF_USED) ;
326 bdg_stats.s[ifp->if_index].name[0] = '\0';
331 for (i=0; i < n_clusters; i++) {
332 free(clusters[i].ht, M_IFADDR);
333 free(clusters[i].my_macs, M_IFADDR);
335 if (clusters != NULL)
336 free(clusters, M_IFADDR);
343 * set promisc mode on the interfaces we use.
351 TAILQ_FOREACH(ifp, &ifnet, if_link) {
352 struct bdg_softc *b = &ifp2sc[ifp->if_index];
354 if ( !(b->flags & IFF_USED) )
356 if ( !( ifp->if_flags & IFF_UP) ) {
361 if ( !(b->flags & IFF_BDG_PROMISC) ) {
364 ret = ifpromisc(ifp, 1);
366 b->flags |= IFF_BDG_PROMISC ;
367 DEB(printf(">> now %s%d promisc ON if_flags 0x%x bdg_flags 0x%x\n",
368 ifp->if_name, ifp->if_unit,
369 ifp->if_flags, b->flags);)
371 if (b->flags & IFF_MUTE) {
372 DEB(printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);)
373 b->flags &= ~IFF_MUTE;
379 * reconfigure bridge.
380 * This is also done every time we attach or detach an interface.
381 * Main use is to make sure that we do not bridge on some old
382 * (ejected) device. So, it would be really useful to have a
383 * pointer to the modified device as an argument. Without it, we
384 * have to scan all interfaces.
387 reconfigure_bridge(void)
391 if (if_index >= BDG_MAX_PORTS) {
392 printf("-- sorry too many interfaces (%d, max is %d),"
393 " disabling bridging\n", if_index, BDG_MAX_PORTS);
402 static char bridge_cfg[1024]; /* in BSS so initialized to all NULs */
405 * parse the config string, set IFF_USED, name and cluster_id
406 * for all interfaces found.
407 * The config string is a list of "if[:cluster]" with
408 * a number of possible separators (see "sep"). In particular the
409 * use of the space lets you set bridge_cfg with the output from
417 static char *sep = ", \t";
419 for (p = bridge_cfg; *p ; p++) {
424 if (index(sep, *p)) /* skip separators */
426 /* names are lowercase and digits */
427 for ( beg = p ; islower(*p) || isdigit(*p) ; p++ )
429 l = p - beg ; /* length of name string */
430 if (l == 0) /* invalid name */
432 if ( *p != ':' ) /* no ':', assume default cluster 1 */
434 else /* fetch cluster */
435 cluster = strtoul( p+1, &p, 10);
439 * now search in interface list for a matching name
441 TAILQ_FOREACH(ifp, &ifnet, if_link) {
444 snprintf(buf, sizeof(buf), "%s%d", ifp->if_name, ifp->if_unit);
445 if (!strncmp(beg, buf, max(l, strlen(buf)))) {
446 struct bdg_softc *b = &ifp2sc[ifp->if_index];
447 if (ifp->if_type != IFT_ETHER && ifp->if_type != IFT_L2VLAN) {
448 printf("%s is not an ethernet, continue\n", buf);
451 if (b->flags & IFF_USED) {
452 printf("%s already used, skipping\n", buf);
455 b->cluster = add_cluster(htons(cluster), (struct arpcom *)ifp);
456 b->flags |= IFF_USED ;
457 sprintf(bdg_stats.s[ifp->if_index].name,
458 "%s%d:%d", ifp->if_name, ifp->if_unit, cluster);
460 DEB(printf("--++ found %s next c %d\n",
461 bdg_stats.s[ifp->if_index].name, c);)
467 printf("interface %s Not found in bridge\n", beg);
476 * handler for net.link.ether.bridge
479 sysctl_bdg(SYSCTL_HANDLER_ARGS)
481 int error, oldval = do_bridge ;
483 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
484 DEB( printf("called sysctl for bridge name %s arg2 %d val %d->%d\n",
485 oidp->oid_name, oidp->oid_arg2,
486 oldval, do_bridge); )
488 if (oldval != do_bridge)
489 reconfigure_bridge();
494 * handler for net.link.ether.bridge_cfg
497 sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
502 strcpy(old_cfg, bridge_cfg) ;
504 error = sysctl_handle_string(oidp, bridge_cfg, oidp->oid_arg2, req);
506 printf("called sysctl for bridge name %s arg2 %d err %d val %s->%s\n",
507 oidp->oid_name, oidp->oid_arg2,
509 old_cfg, bridge_cfg);
511 if (strcmp(old_cfg, bridge_cfg))
512 reconfigure_bridge();
517 sysctl_refresh(SYSCTL_HANDLER_ARGS)
520 reconfigure_bridge();
526 SYSCTL_DECL(_net_link_ether);
527 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_cfg, CTLTYPE_STRING|CTLFLAG_RW,
528 &bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
529 "Bridge configuration");
531 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge, CTLTYPE_INT|CTLFLAG_RW,
532 &do_bridge, 0, &sysctl_bdg, "I", "Bridging");
534 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
535 &bdg_ipfw,0,"Pass bridged pkts through firewall");
537 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipf, CTLFLAG_RW,
538 &bdg_ipf, 0,"Pass bridged pkts through IPFilter");
541 * The follow macro declares a variable, and maps it to
542 * a SYSCTL_INT entry with the same name.
544 #define SY(parent, var, comment) \
546 SYSCTL_INT(parent, OID_AUTO, var, CTLFLAG_RW, &(var), 0, comment);
549 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_drop,
550 CTLFLAG_RW, &bdg_ipfw_drops,0,"");
553 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_collisions,
554 CTLFLAG_RW, &bdg_ipfw_colls,0,"");
556 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_refresh, CTLTYPE_INT|CTLFLAG_WR,
557 NULL, 0, &sysctl_refresh, "I", "iface refresh");
559 #if 1 /* diagnostic vars */
561 SY(_net_link_ether, verbose, "Be verbose");
562 SY(_net_link_ether, bdg_split_pkts, "Packets split in bdg_forward");
564 SY(_net_link_ether, bdg_thru, "Packets through bridge");
566 SY(_net_link_ether, bdg_copied, "Packets copied in bdg_forward");
568 SY(_net_link_ether, bdg_copy, "Force copy in bdg_forward");
569 SY(_net_link_ether, bdg_predict, "Correctly predicted header location");
571 SY(_net_link_ether, bdg_fw_avg, "Cycle counter avg");
572 SY(_net_link_ether, bdg_fw_ticks, "Cycle counter item");
573 SY(_net_link_ether, bdg_fw_count, "Cycle counter count");
576 SYSCTL_STRUCT(_net_link_ether, PF_BDG, bdgstats,
577 CTLFLAG_RD, &bdg_stats , bdg_stats, "bridge statistics");
579 static int bdg_loops ;
582 * called periodically to flush entries etc.
585 bdg_timeout(void *dummy)
587 static int slowtimer; /* in BSS so initialized to 0 */
590 static int age_index = 0 ; /* index of table position to age */
591 int l = age_index + HASH_SIZE/4 ;
594 * age entries in the forwarding table.
599 for (i=0; i<n_clusters; i++) {
600 bdg_hash_table *bdg_table = clusters[i].ht;
601 for (; age_index < l ; age_index++)
602 if (bdg_table[age_index].used)
603 bdg_table[age_index].used = 0 ;
604 else if (bdg_table[age_index].name) {
605 /* printf("xx flushing stale entry %d\n", age_index); */
606 bdg_table[age_index].name = NULL ;
609 if (age_index >= HASH_SIZE)
612 if (--slowtimer <= 0 ) {
615 bridge_on() ; /* we just need unmute, really */
619 bdg_timeout_h = timeout(bdg_timeout, NULL, 2*hz );
623 * Find the right pkt destination:
624 * BDG_BCAST is a broadcast
625 * BDG_MCAST is a multicast
626 * BDG_LOCAL is for a local address
627 * BDG_DROP must be dropped
628 * other ifp of the dest. interface (incl.self)
630 * We assume this is only called for interfaces for which bridging
631 * is enabled, i.e. BDG_USED(ifp) is true.
635 bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c)
640 bdg_hash_table *bt; /* pointer to entry in hash table */
642 if (IS_ETHER_BROADCAST(eh->ether_dhost))
644 if (eh->ether_dhost[0] & 1)
647 * Lookup local addresses in case one matches.
649 for (index = c->ports, p = c->my_macs; index ; index--, p++ )
650 if (BDG_MATCH(p->etheraddr, eh->ether_dhost) )
653 * Look for a possible destination in table
655 index= HASH_FN( eh->ether_dhost );
656 bt = &(c->ht[index]);
658 if ( dst && BDG_MATCH( bt->etheraddr, eh->ether_dhost) )
665 * bridge_in() is invoked to perform bridging decision on input packets.
668 * eh Ethernet header of the incoming packet.
669 * ifp interface the packet is coming from.
671 * On Return: destination of packet, one of
672 * BDG_BCAST broadcast
673 * BDG_MCAST multicast
674 * BDG_LOCAL is only for a local address (do not forward)
675 * BDG_DROP drop the packet
676 * ifp ifp of the destination interface.
678 * Forwarding is not done directly to give a chance to some drivers
679 * to fetch more of the packet, or simply drop it completely.
682 static struct ifnet *
683 bridge_in(struct ifnet *ifp, struct ether_header *eh)
686 struct ifnet *dst , *old ;
687 bdg_hash_table *bt; /* location in hash table */
688 int dropit = BDG_MUTED(ifp) ;
691 * hash the source address
693 index= HASH_FN(eh->ether_shost);
694 bt = &(ifp2sc[ifp->if_index].cluster->ht[index]);
697 if ( old ) { /* the entry is valid. */
698 if (!BDG_MATCH( eh->ether_shost, bt->etheraddr) ) {
701 } else if (old != ifp) {
703 * Found a loop. Either a machine has moved, or there
704 * is a misconfiguration/reconfiguration of the network.
705 * First, do not forward this packet!
706 * Record the relocation anyways; then, if loops persist,
707 * suspect a reconfiguration and disable forwarding
708 * from the old interface.
710 bt->name = ifp ; /* relocate address */
711 printf("-- loop (%d) %6D to %s%d from %s%d (%s)\n",
712 bdg_loops, eh->ether_shost, ".",
713 ifp->if_name, ifp->if_unit,
714 old->if_name, old->if_unit,
715 BDG_MUTED(old) ? "muted":"active");
717 if ( !BDG_MUTED(old) ) {
718 if (++bdg_loops > 10)
725 * now write the source address into the table
727 if (bt->name == NULL) {
728 DEB(printf("new addr %6D at %d for %s%d\n",
729 eh->ether_shost, ".", index, ifp->if_name, ifp->if_unit);)
730 bcopy(eh->ether_shost, bt->etheraddr, 6);
733 dst = bridge_dst_lookup(eh, ifp2sc[ifp->if_index].cluster);
735 * bridge_dst_lookup can return the following values:
736 * BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp.
737 * For muted interfaces, or when we detect a loop, the first 3 are
738 * changed in BDG_LOCAL (we still listen to incoming traffic),
739 * and others to BDG_DROP (no use for the local host).
740 * Also, for incoming packets, ifp is changed to BDG_DROP if ifp == src.
741 * These changes are not necessary for outgoing packets from ether_output().
743 BDG_STAT(ifp, BDG_IN);
744 switch ((uintptr_t)dst) {
745 case (uintptr_t)BDG_BCAST:
746 case (uintptr_t)BDG_MCAST:
747 case (uintptr_t)BDG_LOCAL:
748 case (uintptr_t)BDG_UNKNOWN:
749 case (uintptr_t)BDG_DROP:
753 if (dst == ifp || dropit)
754 BDG_STAT(ifp, BDG_DROP);
756 BDG_STAT(ifp, BDG_FORWARD);
761 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_LOCAL)
769 DEB(printf("bridge_in %6D ->%6D ty 0x%04x dst %s%d\n",
770 eh->ether_shost, ".",
771 eh->ether_dhost, ".",
772 ntohs(eh->ether_type),
773 (dst <= BDG_FORWARD) ? bdg_dst_names[(int)dst] :
775 (dst <= BDG_FORWARD) ? 0 : dst->if_unit); )
781 * Forward a packet to dst -- which can be a single interface or
782 * an entire cluster. The src port and muted interfaces are excluded.
784 * If src == NULL, the pkt comes from ether_output, and dst is the real
785 * interface the packet is originally sent to. In this case, we must forward
786 * it to the whole cluster.
787 * We never call bdg_forward from ether_output on interfaces which are
788 * not part of a cluster.
790 * If possible (i.e. we can determine that the caller does not need
791 * a copy), the packet is consumed here, and bdg_forward returns NULL.
792 * Otherwise, a pointer to a copy of the packet is returned.
794 * XXX be careful with eh, it can be a pointer into *m
797 bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
800 struct ifnet *ifp, *last;
801 int shared = bdg_copy ; /* someone else is using the mbuf */
802 int once = 0; /* loop only once */
803 struct ifnet *real_dst = dst ; /* real dst from ether_output */
804 struct ip_fw_args args;
807 * XXX eh is usually a pointer within the mbuf (some ethernet drivers
808 * do that), so we better copy it before doing anything with the mbuf,
809 * or we might corrupt the header.
811 struct ether_header save_eh = *eh ;
813 DEB(quad_t ticks; ticks = rdtsc();)
815 args.rule = NULL; /* did we match a firewall rule ? */
816 /* Fetch state from dummynet tag, ignore others */
817 for (;m0->m_type == MT_TAG; m0 = m0->m_next)
818 if (m0->_m_tag_id == PACKET_TAG_DUMMYNET) {
819 args.rule = ((struct dn_pkt *)m0)->rule;
820 shared = 0; /* For sure this is our own mbuf. */
822 if (args.rule == NULL)
823 bdg_thru++; /* first time through bdg_forward, count packet */
825 src = m0->m_pkthdr.rcvif;
826 if (src == NULL) /* packet from ether_output */
827 dst = bridge_dst_lookup(eh, ifp2sc[real_dst->if_index].cluster);
829 if (dst == BDG_DROP) { /* this should not happen */
830 printf("xx bdg_forward for BDG_DROP\n");
834 if (dst == BDG_LOCAL) { /* this should not happen as well */
835 printf("xx ouch, bdg_forward for local pkt\n");
838 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
839 ifp = TAILQ_FIRST(&ifnet) ; /* scan all ports */
841 if (dst != BDG_UNKNOWN) /* need a copy for the local stack */
847 if ( (uintptr_t)(ifp) <= (u_int)BDG_FORWARD )
848 panic("bdg_forward: bad dst");
851 * Do filtering in a very similar way to what is done in ip_output.
852 * Only if firewall is loaded, enabled, and the packet is not
853 * from ether_output() (src==NULL, or we would filter it twice).
854 * Additional restrictions may apply e.g. non-IP, short packets,
855 * and pkts already gone through a pipe.
858 (fr_checkp != NULL && bdg_ipf != 0) ||
859 (IPFW_LOADED && bdg_ipfw != 0))) {
863 if (args.rule != NULL && fw_one_pass)
864 goto forward; /* packet already partially processed */
866 * i need some amt of data to be contiguous, and in case others need
867 * the packet (shared==1) also better be in the first mbuf.
869 i = min(m0->m_pkthdr.len, max_protohdr) ;
870 if ( shared || m0->m_len < i) {
871 m0 = m_pullup(m0, i) ;
873 printf("-- bdg: pullup failed.\n") ;
881 if (fr_checkp != NULL && bdg_ipf &&
882 m0->m_pkthdr.len >= sizeof(struct ip) &&
883 ntohs(save_eh.ether_type) == ETHERTYPE_IP) {
885 * before calling the firewall, swap fields the same as IP does.
886 * here we assume the pkt is an IP one and the header is contiguous
888 struct ip *ip = mtod(m0, struct ip *);
890 ip->ip_len = ntohs(ip->ip_len);
891 ip->ip_off = ntohs(ip->ip_off);
893 if ((*fr_checkp)(ip, ip->ip_hl << 2, src, 0, &m0) || m0 == NULL)
897 * If we get here, the firewall has passed the pkt, but the mbuf
898 * pointer might have changed. Restore ip and the fields ntohs()'d.
900 ip = mtod(m0, struct ip *);
901 ip->ip_len = htons(ip->ip_len);
902 ip->ip_off = htons(ip->ip_off);
906 * Prepare arguments and call the firewall.
908 if (!IPFW_LOADED || bdg_ipfw == 0)
909 goto forward; /* not using ipfw, accept the packet */
912 * XXX The following code is very similar to the one in
913 * if_ethersubr.c:ether_ipfw_chk()
916 args.m = m0; /* the packet we are looking at */
917 args.oif = NULL; /* this is an input packet */
918 args.divert_rule = 0; /* we do not support divert yet */
919 args.next_hop = NULL; /* we do not support forward yet */
920 args.eh = &save_eh; /* MAC header for bridged/MAC packets */
921 i = ip_fw_chk_ptr(&args);
922 m0 = args.m; /* in case the firewall used the mbuf */
924 if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */
927 if (i == 0) /* a PASS rule. */
929 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) {
931 * Pass the pkt to dummynet, which consumes it.
932 * If shared, make a copy and keep the original.
937 m = m_copypacket(m0, M_DONTWAIT);
938 if (m == NULL) /* copy failed, give up */
941 m = m0 ; /* pass the original to dummynet */
942 m0 = NULL ; /* and nothing back to the caller */
945 * Prepend the header, optimize for the common case of
946 * eh pointing into the mbuf.
948 if ( (void *)(eh + 1) == (void *)m->m_data) {
949 m->m_data -= ETHER_HDR_LEN ;
950 m->m_len += ETHER_HDR_LEN ;
951 m->m_pkthdr.len += ETHER_HDR_LEN ;
954 M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
955 if (m == NULL) /* nope... */
957 bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
961 ip_dn_io_ptr(m, (i & 0xffff),DN_TO_BDG_FWD, &args);
965 * XXX at some point, add support for divert/forward actions.
966 * If none of the above matches, we have to drop the packet.
973 * Again, bring up the headers in case of shared bufs to avoid
974 * corruptions in the future.
977 int i = min(m0->m_pkthdr.len, max_protohdr) ;
979 m0 = m_pullup(m0, i) ;
984 * now real_dst is used to determine the cluster where to forward.
985 * For packets coming from ether_input, this is the one of the 'src'
986 * interface, whereas for locally generated packets (src==NULL) it
987 * is the cluster of the original destination interface, which
988 * was already saved into real_dst.
995 if (last) { /* need to forward packet leftover from previous loop */
997 if (shared == 0 && once ) { /* no need to copy */
999 m0 = NULL ; /* original is gone */
1001 m = m_copypacket(m0, M_DONTWAIT);
1003 printf("bdg_forward: sorry, m_copypacket failed!\n");
1004 return m0 ; /* the original is still there... */
1008 * Add header (optimized for the common case of eh pointing
1009 * already into the mbuf) and execute last part of ether_output:
1010 * queue pkt and start output if interface not yet active.
1012 if ( (void *)(eh + 1) == (void *)m->m_data) {
1013 m->m_data -= ETHER_HDR_LEN ;
1014 m->m_len += ETHER_HDR_LEN ;
1015 m->m_pkthdr.len += ETHER_HDR_LEN ;
1018 M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
1020 printf("M_PREPEND failed\n");
1023 bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
1025 if (!IF_HANDOFF(&last->if_snd, m, last)) {
1027 BDG_MUTE(last); /* should I also mute ? */
1030 BDG_STAT(last, BDG_OUT);
1038 * If the interface is used for bridging, not muted, not full,
1039 * up and running, is not the source interface, and belongs to
1040 * the same cluster as the 'real_dst', then send here.
1042 if ( BDG_USED(ifp) && !BDG_MUTED(ifp) && !_IF_QFULL(&ifp->if_snd) &&
1043 (ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING) &&
1044 ifp != src && BDG_SAMECLUSTER(ifp, real_dst) )
1046 ifp = TAILQ_NEXT(ifp, if_link) ;
1050 DEB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;
1051 if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; )
1056 * initialization of bridge code.
1061 printf("BRIDGE 020214 loaded\n");
1063 ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
1064 M_IFADDR, M_WAITOK | M_ZERO );
1068 bridge_in_ptr = bridge_in;
1069 bdg_forward_ptr = bdg_forward;
1070 bdgtakeifaces_ptr = reconfigure_bridge;
1076 bzero(&bdg_stats, sizeof(bdg_stats) );
1077 bdgtakeifaces_ptr();
1083 * initialization code, both for static and dynamic loading.
1086 bridge_modevent(module_t mod, int type, void *unused)
1102 #if !defined(KLD_MODULE)
1103 printf("bridge statically compiled, cannot unload\n");
1108 bridge_in_ptr = NULL;
1109 bdg_forward_ptr = NULL;
1110 bdgtakeifaces_ptr = NULL;
1111 untimeout(bdg_timeout, NULL, bdg_timeout_h);
1114 free(clusters, M_IFADDR);
1115 free(ifp2sc, M_IFADDR);
1127 static moduledata_t bridge_mod = {
1133 DECLARE_MODULE(bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
1134 MODULE_VERSION(bridge, 1);