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 $
28 * $DragonFly: src/sys/net/oldbridge/Attic/bridge.c,v 1.18 2005/07/05 10:20:39 corecode Exp $
32 * This code implements bridging in FreeBSD. It only acts on ethernet
33 * interfaces, including VLANs (others are still usable for routing).
34 * A FreeBSD host can implement multiple logical bridges, called
35 * "clusters". Each cluster is made of a set of interfaces, and
36 * identified by a "cluster-id" which is a number in the range 1..2^16-1.
38 * Bridging is enabled by the sysctl variable
39 * net.link.ether.bridge
40 * the grouping of interfaces into clusters is done with
41 * net.link.ether.bridge_cfg
42 * containing a list of interfaces each optionally followed by
43 * a colon and the cluster it belongs to (1 is the default).
44 * Separators can be * spaces, commas or tabs, e.g.
45 * net.link.ether.bridge_cfg="fxp0:2 fxp1:2 dc0 dc1:1"
46 * Optionally bridged packets can be passed through the firewall,
47 * this is controlled by the variable
48 * net.link.ether.bridge_ipfw
50 * For each cluster there is a descriptor (cluster_softc) storing
51 * the following data structures:
52 * - a hash table with the MAC address and destination interface for each
53 * known node. The table is indexed using a hash of the source address.
54 * - an array with the MAC addresses of the interfaces used in the cluster.
56 * Input packets are tapped near the beginning of ether_input(), and
57 * analysed by bridge_in(). Depending on the result, the packet
58 * can be forwarded to one or more output interfaces using bdg_forward(),
59 * and/or sent to the upper layer (e.g. in case of multicast).
61 * Output packets are intercepted near the end of ether_output().
62 * The correct destination is selected by bridge_dst_lookup(),
63 * and then forwarding is done by bdg_forward().
65 * The arp code is also modified to let a machine answer to requests
66 * irrespective of the port the request came from.
68 * In case of loops in the bridging topology, the bridge detects this
69 * event and temporarily mutes output bridging on one of the ports.
70 * Periodically, interfaces are unmuted by bdg_timeout().
71 * Muting is only implemented as a safety measure, and also as
72 * a mechanism to support a user-space implementation of the spanning
75 * To build a bridging kernel, use the following option
77 * and then at runtime set the sysctl variable to enable bridging.
79 * Only one interface per cluster is supposed to have addresses set (but
80 * there are no substantial problems if you set addresses for none or
81 * for more than one interface).
82 * Bridging will act before routing, but nothing prevents a machine
83 * from doing both (modulo bugs in the implementation...).
86 * - bridging is incompatible with multicast routing on the same
87 * machine. There is not an easy fix to this.
88 * - be very careful when bridging VLANs
89 * - loop detection is still not very robust.
92 #include <sys/param.h>
94 #include <sys/malloc.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/sysctl.h>
100 #include <sys/thread2.h>
103 #include <net/if_types.h>
104 #include <net/if_llc.h>
105 #include <net/if_var.h>
106 #include <net/ifq_var.h>
107 #include <net/pfil.h>
109 #include <netinet/in.h> /* for struct arpcom */
110 #include <netinet/in_systm.h>
111 #include <netinet/in_var.h>
112 #include <netinet/ip.h>
113 #include <netinet/ip_var.h>
114 #include <netinet/if_ether.h> /* for struct arpcom */
116 #include <net/route.h>
117 #include <net/ipfw/ip_fw.h>
118 #include <net/dummynet/ip_dummynet.h>
121 /*--------------------*/
124 * For each cluster, source MAC addresses are stored into a hash
125 * table which locates the port they reside on.
127 #define HASH_SIZE 8192 /* Table size, must be a power of 2 */
129 typedef struct hash_table { /* each entry. */
132 u_int16_t used; /* also, padding */
136 * The hash function applied to MAC addresses. Out of the 6 bytes,
137 * the last ones tend to vary more. Since we are on a little endian machine,
138 * we have to do some gimmick...
140 #define HASH_FN(addr) ( \
141 ntohs( ((u_int16_t *)addr)[1] ^ ((u_int16_t *)addr)[2] ) & (HASH_SIZE -1))
144 * This is the data structure where local addresses are stored.
147 u_char etheraddr[6] ;
152 * The configuration of each cluster includes the cluster id, a pointer to
153 * the hash table, and an array of local MAC addresses (of size "ports").
155 struct cluster_softc {
156 u_int16_t cluster_id;
159 struct bdg_addr *my_macs; /* local MAC addresses */
163 extern struct protosw inetsw[]; /* from netinet/ip_input.c */
165 static int n_clusters; /* number of clusters */
166 static struct cluster_softc *clusters;
168 #define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
169 #define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
170 #define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster)
172 #define BDG_SAMECLUSTER(ifp,src) \
173 (src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) )
176 #define BDG_MATCH(a,b) ( \
177 ((u_int16_t *)(a))[2] == ((u_int16_t *)(b))[2] && \
178 *((u_int32_t *)(a)) == *((u_int32_t *)(b)) )
179 #define IS_ETHER_BROADCAST(a) ( \
180 *((u_int32_t *)(a)) == 0xffffffff && \
181 ((u_int16_t *)(a))[2] == 0xffff )
183 /* for machines that do not support unaligned access */
184 #define BDG_MATCH(a,b) (!bcmp(a, b, ETHER_ADDR_LEN) )
185 #define IS_ETHER_BROADCAST(a) (!bcmp(a, "\377\377\377\377\377\377", 6))
190 * For timing-related debugging, you can use the following macros.
191 * remember, rdtsc() only works on Pentium-class machines
194 DDB(ticks = rdtsc();)
195 ... interesting code ...
196 DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;)
204 static int bdginit(void);
205 static void parse_bdg_cfg(void);
207 static int bdg_pfil; /* PFIL hooks enabled in bridge */
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 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_WAITOK | M_ZERO);
246 c[n_clusters].ht = malloc(HASH_SIZE * sizeof(struct hash_table),
247 M_IFADDR, M_WAITOK | M_ZERO);
248 c[n_clusters].my_macs = malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr),
249 M_IFADDR, M_WAITOK | M_ZERO);
251 c[n_clusters].cluster_id = cluster_id;
252 c[n_clusters].ports = 0;
254 * now copy old descriptors here
256 if (n_clusters > 0) {
257 for (i=0; i < n_clusters; i++)
260 * and finally update pointers in ifp2sc
262 for (i = 0 ; i < if_index && i < BDG_MAX_PORTS; i++)
263 if (ifp2sc[i].cluster != NULL)
264 ifp2sc[i].cluster = c + (ifp2sc[i].cluster - clusters);
265 free(clusters, M_IFADDR);
268 i = n_clusters; /* index of cluster entry */
271 c = clusters + i; /* the right cluster ... */
272 bcopy(ac->ac_enaddr, &(c->my_macs[c->ports]), 6);
279 * Turn off bridging, by clearing promisc mode on the interface,
280 * marking the interface as unused, and clearing the name in the
282 * Also dispose the hash tables associated with the clusters.
290 DEB(printf("bridge_off: n_clusters %d\n", n_clusters);)
291 TAILQ_FOREACH(ifp, &ifnet, if_link) {
294 if (ifp->if_index >= BDG_MAX_PORTS)
295 continue; /* make sure we do not go beyond the end */
296 b = &(ifp2sc[ifp->if_index]);
298 if ( b->flags & IFF_BDG_PROMISC ) {
302 b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
303 DEB(printf(">> now %s promisc OFF if_flags 0x%x bdg_flags 0x%x\n",
305 ifp->if_flags, b->flags);)
307 b->flags &= ~(IFF_USED) ;
309 bdg_stats.s[ifp->if_index].name[0] = '\0';
314 for (i=0; i < n_clusters; i++) {
315 free(clusters[i].ht, M_IFADDR);
316 free(clusters[i].my_macs, M_IFADDR);
318 if (clusters != NULL)
319 free(clusters, M_IFADDR);
326 * set promisc mode on the interfaces we use.
333 TAILQ_FOREACH(ifp, &ifnet, if_link) {
334 struct bdg_softc *b = &ifp2sc[ifp->if_index];
336 if ( !(b->flags & IFF_USED) )
338 if ( !( ifp->if_flags & IFF_UP) ) {
343 if ( !(b->flags & IFF_BDG_PROMISC) ) {
346 ret = ifpromisc(ifp, 1);
348 b->flags |= IFF_BDG_PROMISC ;
349 DEB(printf(">> now %s promisc ON if_flags 0x%x bdg_flags 0x%x\n",
351 ifp->if_flags, b->flags);)
353 if (b->flags & IFF_MUTE) {
354 DEB(printf(">> unmuting %s\n", ifp->if_xname);)
355 b->flags &= ~IFF_MUTE;
361 * reconfigure bridge.
362 * This is also done every time we attach or detach an interface.
363 * Main use is to make sure that we do not bridge on some old
364 * (ejected) device. So, it would be really useful to have a
365 * pointer to the modified device as an argument. Without it, we
366 * have to scan all interfaces.
369 reconfigure_bridge(void)
373 if (if_index >= BDG_MAX_PORTS) {
374 printf("-- sorry too many interfaces (%d, max is %d),"
375 " disabling bridging\n", if_index, BDG_MAX_PORTS);
384 static char bridge_cfg[1024]; /* in BSS so initialized to all NULs */
387 * parse the config string, set IFF_USED, name and cluster_id
388 * for all interfaces found.
389 * The config string is a list of "if[:cluster]" with
390 * a number of possible separators (see "sep"). In particular the
391 * use of the space lets you set bridge_cfg with the output from
399 static char *sep = ", \t";
401 for (p = bridge_cfg; *p ; p++) {
406 if (index(sep, *p)) /* skip separators */
408 /* names are lowercase and digits */
409 for ( beg = p ; islower(*p) || isdigit(*p) ; p++ )
411 l = p - beg ; /* length of name string */
412 if (l == 0) /* invalid name */
414 if ( *p != ':' ) /* no ':', assume default cluster 1 */
416 else /* fetch cluster */
417 cluster = strtoul( p+1, &p, 10);
421 * now search in interface list for a matching name
423 TAILQ_FOREACH(ifp, &ifnet, if_link) {
426 snprintf(buf, sizeof(buf), "%s", ifp->if_xname);
427 if (!strncmp(beg, buf, max(l, strlen(buf)))) {
428 struct bdg_softc *b = &ifp2sc[ifp->if_index];
429 if (ifp->if_type != IFT_ETHER && ifp->if_type != IFT_L2VLAN) {
430 printf("%s is not an ethernet, continue\n", buf);
433 if (b->flags & IFF_USED) {
434 printf("%s already used, skipping\n", buf);
437 b->cluster = add_cluster(htons(cluster), (struct arpcom *)ifp);
438 b->flags |= IFF_USED ;
439 sprintf(bdg_stats.s[ifp->if_index].name,
440 "%s:%d", ifp->if_xname, cluster);
442 DEB(printf("--++ found %s next c %d\n",
443 bdg_stats.s[ifp->if_index].name, c);)
449 printf("interface %s Not found in bridge\n", beg);
458 * handler for net.link.ether.bridge
461 sysctl_bdg(SYSCTL_HANDLER_ARGS)
463 int error, oldval = do_bridge ;
465 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
466 DEB( printf("called sysctl for bridge name %s arg2 %d val %d->%d\n",
467 oidp->oid_name, oidp->oid_arg2,
468 oldval, do_bridge); )
470 if (oldval != do_bridge)
471 reconfigure_bridge();
476 * handler for net.link.ether.bridge_cfg
479 sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
484 strcpy(old_cfg, bridge_cfg) ;
486 error = sysctl_handle_string(oidp, bridge_cfg, oidp->oid_arg2, req);
488 printf("called sysctl for bridge name %s arg2 %d err %d val %s->%s\n",
489 oidp->oid_name, oidp->oid_arg2,
491 old_cfg, bridge_cfg);
493 if (strcmp(old_cfg, bridge_cfg))
494 reconfigure_bridge();
499 sysctl_refresh(SYSCTL_HANDLER_ARGS)
502 reconfigure_bridge();
508 SYSCTL_DECL(_net_link_ether);
509 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_cfg, CTLTYPE_STRING|CTLFLAG_RW,
510 &bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
511 "Bridge configuration");
513 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge, CTLTYPE_INT|CTLFLAG_RW,
514 &do_bridge, 0, &sysctl_bdg, "I", "Bridging");
516 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
517 &bdg_ipfw,0,"Pass bridged pkts through IPFW");
519 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_pfil, CTLFLAG_RW,
520 &bdg_pfil, 0,"Pass bridged pkts through PFIL hooks");
523 * The follow macro declares a variable, and maps it to
524 * a SYSCTL_INT entry with the same name.
526 #define SY(parent, var, comment) \
528 SYSCTL_INT(parent, OID_AUTO, var, CTLFLAG_RW, &(var), 0, comment);
531 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_drop,
532 CTLFLAG_RW, &bdg_ipfw_drops,0,"");
535 SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_collisions,
536 CTLFLAG_RW, &bdg_ipfw_colls,0,"");
538 SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_refresh, CTLTYPE_INT|CTLFLAG_WR,
539 NULL, 0, &sysctl_refresh, "I", "iface refresh");
541 #if 1 /* diagnostic vars */
543 SY(_net_link_ether, verbose, "Be verbose");
544 SY(_net_link_ether, bdg_split_pkts, "Packets split in bdg_forward");
546 SY(_net_link_ether, bdg_thru, "Packets through bridge");
548 SY(_net_link_ether, bdg_copied, "Packets copied in bdg_forward");
550 SY(_net_link_ether, bdg_copy, "Force copy in bdg_forward");
551 SY(_net_link_ether, bdg_predict, "Correctly predicted header location");
553 SY(_net_link_ether, bdg_fw_avg, "Cycle counter avg");
554 SY(_net_link_ether, bdg_fw_ticks, "Cycle counter item");
555 SY(_net_link_ether, bdg_fw_count, "Cycle counter count");
558 SYSCTL_STRUCT(_net_link_ether, PF_BDG, bdgstats,
559 CTLFLAG_RD, &bdg_stats , bdg_stats, "bridge statistics");
561 static int bdg_loops ;
564 * called periodically to flush entries etc.
567 bdg_timeout(void *dummy)
569 static int slowtimer; /* in BSS so initialized to 0 */
572 static int age_index = 0 ; /* index of table position to age */
573 int l = age_index + HASH_SIZE/4 ;
576 * age entries in the forwarding table.
581 for (i=0; i<n_clusters; i++) {
582 bdg_hash_table *bdg_table = clusters[i].ht;
583 for (; age_index < l ; age_index++)
584 if (bdg_table[age_index].used)
585 bdg_table[age_index].used = 0 ;
586 else if (bdg_table[age_index].name) {
587 /* printf("xx flushing stale entry %d\n", age_index); */
588 bdg_table[age_index].name = NULL ;
591 if (age_index >= HASH_SIZE)
594 if (--slowtimer <= 0 ) {
597 bridge_on() ; /* we just need unmute, really */
601 callout_reset(&bdg_timeout_h, 2*hz, bdg_timeout, NULL);
605 * Find the right pkt destination:
606 * BDG_BCAST is a broadcast
607 * BDG_MCAST is a multicast
608 * BDG_LOCAL is for a local address
609 * BDG_DROP must be dropped
610 * other ifp of the dest. interface (incl.self)
612 * We assume this is only called for interfaces for which bridging
613 * is enabled, i.e. BDG_USED(ifp) is true.
617 bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c)
622 bdg_hash_table *bt; /* pointer to entry in hash table */
624 if (IS_ETHER_BROADCAST(eh->ether_dhost))
626 if (eh->ether_dhost[0] & 1)
629 * Lookup local addresses in case one matches.
631 for (index = c->ports, p = c->my_macs; index ; index--, p++ )
632 if (BDG_MATCH(p->etheraddr, eh->ether_dhost) )
635 * Look for a possible destination in table
637 index= HASH_FN( eh->ether_dhost );
638 bt = &(c->ht[index]);
640 if ( dst && BDG_MATCH( bt->etheraddr, eh->ether_dhost) )
647 * bridge_in() is invoked to perform bridging decision on input packets.
650 * eh Ethernet header of the incoming packet.
651 * ifp interface the packet is coming from.
653 * On Return: destination of packet, one of
654 * BDG_BCAST broadcast
655 * BDG_MCAST multicast
656 * BDG_LOCAL is only for a local address (do not forward)
657 * BDG_DROP drop the packet
658 * ifp ifp of the destination interface.
660 * Forwarding is not done directly to give a chance to some drivers
661 * to fetch more of the packet, or simply drop it completely.
664 static struct ifnet *
665 bridge_in(struct ifnet *ifp, struct ether_header *eh)
668 struct ifnet *dst , *old ;
669 bdg_hash_table *bt; /* location in hash table */
670 int dropit = BDG_MUTED(ifp) ;
673 * hash the source address
675 index= HASH_FN(eh->ether_shost);
676 bt = &(ifp2sc[ifp->if_index].cluster->ht[index]);
679 if ( old ) { /* the entry is valid. */
680 if (!BDG_MATCH( eh->ether_shost, bt->etheraddr) ) {
683 } else if (old != ifp) {
685 * Found a loop. Either a machine has moved, or there
686 * is a misconfiguration/reconfiguration of the network.
687 * First, do not forward this packet!
688 * Record the relocation anyways; then, if loops persist,
689 * suspect a reconfiguration and disable forwarding
690 * from the old interface.
692 bt->name = ifp ; /* relocate address */
693 printf("-- loop (%d) %6D to %s from %s (%s)\n",
694 bdg_loops, eh->ether_shost, ".",
695 ifp->if_xname, old->if_xname,
696 BDG_MUTED(old) ? "muted":"active");
698 if ( !BDG_MUTED(old) ) {
699 if (++bdg_loops > 10)
706 * now write the source address into the table
708 if (bt->name == NULL) {
709 DEB(printf("new addr %6D at %d for %s\n",
710 eh->ether_shost, ".", index, ifp->if_xname);)
711 bcopy(eh->ether_shost, bt->etheraddr, 6);
714 dst = bridge_dst_lookup(eh, ifp2sc[ifp->if_index].cluster);
716 * bridge_dst_lookup can return the following values:
717 * BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp.
718 * For muted interfaces, or when we detect a loop, the first 3 are
719 * changed in BDG_LOCAL (we still listen to incoming traffic),
720 * and others to BDG_DROP (no use for the local host).
721 * Also, for incoming packets, ifp is changed to BDG_DROP if ifp == src.
722 * These changes are not necessary for outgoing packets from ether_output().
724 BDG_STAT(ifp, BDG_IN);
725 switch ((uintptr_t)dst) {
726 case (uintptr_t)BDG_BCAST:
727 case (uintptr_t)BDG_MCAST:
728 case (uintptr_t)BDG_LOCAL:
729 case (uintptr_t)BDG_UNKNOWN:
730 case (uintptr_t)BDG_DROP:
734 if (dst == ifp || dropit)
735 BDG_STAT(ifp, BDG_DROP);
737 BDG_STAT(ifp, BDG_FORWARD);
742 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_LOCAL)
750 DEB(printf("bridge_in %6D ->%6D ty 0x%04x dst %s\n",
751 eh->ether_shost, ".",
752 eh->ether_dhost, ".",
753 ntohs(eh->ether_type),
754 (dst <= BDG_FORWARD) ? bdg_dst_names[(int)dst]"0" :
761 * Forward a packet to dst -- which can be a single interface or
762 * an entire cluster. The src port and muted interfaces are excluded.
764 * If src == NULL, the pkt comes from ether_output, and dst is the real
765 * interface the packet is originally sent to. In this case, we must forward
766 * it to the whole cluster.
767 * We never call bdg_forward from ether_output on interfaces which are
768 * not part of a cluster.
770 * If possible (i.e. we can determine that the caller does not need
771 * a copy), the packet is consumed here, and bdg_forward returns NULL.
772 * Otherwise, a pointer to a copy of the packet is returned.
774 * XXX be careful with eh, it can be a pointer into *m
777 bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
780 struct ifnet *ifp, *last;
781 int shared = bdg_copy ; /* someone else is using the mbuf */
782 int error, once = 0; /* loop only once */
783 struct ifnet *real_dst = dst ; /* real dst from ether_output */
784 struct ip_fw_args args;
788 * XXX eh is usually a pointer within the mbuf (some ethernet drivers
789 * do that), so we better copy it before doing anything with the mbuf,
790 * or we might corrupt the header.
792 struct ether_header save_eh = *eh ;
794 DEB(quad_t ticks; ticks = rdtsc();)
796 args.rule = NULL; /* did we match a firewall rule ? */
797 /* Fetch state from dummynet tag, ignore others */
798 for (;m0->m_type == MT_TAG; m0 = m0->m_next)
799 if (m0->_m_tag_id == PACKET_TAG_DUMMYNET) {
800 args.rule = ((struct dn_pkt *)m0)->rule;
801 shared = 0; /* For sure this is our own mbuf. */
803 if (args.rule == NULL)
804 bdg_thru++; /* first time through bdg_forward, count packet */
806 src = m0->m_pkthdr.rcvif;
807 if (src == NULL) /* packet from ether_output */
808 dst = bridge_dst_lookup(eh, ifp2sc[real_dst->if_index].cluster);
810 if (dst == BDG_DROP) { /* this should not happen */
811 printf("xx bdg_forward for BDG_DROP\n");
815 if (dst == BDG_LOCAL) { /* this should not happen as well */
816 printf("xx ouch, bdg_forward for local pkt\n");
819 if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
820 ifp = TAILQ_FIRST(&ifnet) ; /* scan all ports */
822 if (dst != BDG_UNKNOWN) /* need a copy for the local stack */
828 if ( (uintptr_t)(ifp) <= (u_int)BDG_FORWARD )
829 panic("bdg_forward: bad dst");
832 * Do filtering in a very similar way to what is done in ip_output.
833 * Only if firewall is loaded, enabled, and the packet is not
834 * from ether_output() (src==NULL, or we would filter it twice).
835 * Additional restrictions may apply e.g. non-IP, short packets,
836 * and pkts already gone through a pipe.
839 (bdg_pfil && pfil_has_hooks(&inet_pfil_hook)) ||
840 (IPFW_LOADED && bdg_ipfw != 0))) {
844 if (args.rule != NULL && fw_one_pass)
845 goto forward; /* packet already partially processed */
847 * i need some amt of data to be contiguous, and in case others need
848 * the packet (shared==1) also better be in the first mbuf.
850 i = min(m0->m_pkthdr.len, max_protohdr) ;
851 if ( shared || m0->m_len < i) {
852 m0 = m_pullup(m0, i) ;
854 printf("-- bdg: pullup failed.\n") ;
860 * PFIL hooks processing
862 if (bdg_pfil && pfil_has_hooks(&inet_pfil_hook) &&
863 m0->m_pkthdr.len >= sizeof(struct ip) &&
864 ntohs(save_eh.ether_type) == ETHERTYPE_IP) {
866 * before calling the firewall, swap fields the same as IP does.
867 * here we assume the pkt is an IP one and the header is contiguous
869 struct ip *ip = mtod(m0, struct ip *);
872 ip->ip_len = ntohs(ip->ip_len);
873 ip->ip_off = ntohs(ip->ip_off);
876 * XXX I think this needs to be reworked to enable stateful
877 * filtering. Think about this. For now, declare the packet as incoming.
879 error = pfil_run_hooks(&inet_pfil_hook, &m0, src, PFIL_IN);
880 if (error != 0 || m0 == NULL)
884 * If we get here, the firewall has passed the pkt, but the mbuf
885 * pointer might have changed. Restore ip and the fields ntohs()'d.
887 ip = mtod(m0, struct ip *);
888 ip->ip_len = htons(ip->ip_len);
889 ip->ip_off = htons(ip->ip_off);
893 * Prepare arguments and call the firewall.
895 if (!IPFW_LOADED || bdg_ipfw == 0)
896 goto forward; /* not using ipfw, accept the packet */
899 * XXX The following code is very similar to the one in
900 * if_ethersubr.c:ether_ipfw_chk()
903 args.m = m0; /* the packet we are looking at */
904 args.oif = NULL; /* this is an input packet */
906 /* no divert support */
907 if ((mtag = m_tag_find(m0, PACKET_TAG_IPFW_DIVERT, NULL)) != NULL)
908 m_tag_delete(m0, mtag);
910 args.next_hop = NULL; /* we do not support forward yet */
911 args.eh = &save_eh; /* MAC header for bridged/MAC packets */
912 i = ip_fw_chk_ptr(&args);
913 m0 = args.m; /* in case the firewall used the mbuf */
915 if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */
918 if (i == 0) /* a PASS rule. */
920 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) {
922 * Pass the pkt to dummynet, which consumes it.
923 * If shared, make a copy and keep the original.
928 m = m_copypacket(m0, MB_DONTWAIT);
929 if (m == NULL) /* copy failed, give up */
932 m = m0 ; /* pass the original to dummynet */
933 m0 = NULL ; /* and nothing back to the caller */
936 * Prepend the header, optimize for the common case of
937 * eh pointing into the mbuf.
939 if ( (void *)(eh + 1) == (void *)m->m_data) {
940 m->m_data -= ETHER_HDR_LEN ;
941 m->m_len += ETHER_HDR_LEN ;
942 m->m_pkthdr.len += ETHER_HDR_LEN ;
945 M_PREPEND(m, ETHER_HDR_LEN, MB_DONTWAIT);
946 if (m == NULL) /* nope... */
948 bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
952 ip_dn_io_ptr(m, (i & 0xffff),DN_TO_BDG_FWD, &args);
956 * XXX at some point, add support for divert/forward actions.
957 * If none of the above matches, we have to drop the packet.
964 * Again, bring up the headers in case of shared bufs to avoid
965 * corruptions in the future.
968 int i = min(m0->m_pkthdr.len, max_protohdr) ;
970 m0 = m_pullup(m0, i) ;
975 * now real_dst is used to determine the cluster where to forward.
976 * For packets coming from ether_input, this is the one of the 'src'
977 * interface, whereas for locally generated packets (src==NULL) it
978 * is the cluster of the original destination interface, which
979 * was already saved into real_dst.
986 if (last) { /* need to forward packet leftover from previous loop */
988 struct altq_pktattr pktattr;
990 if (shared == 0 && once ) { /* no need to copy */
992 m0 = NULL ; /* original is gone */
994 m = m_copypacket(m0, MB_DONTWAIT);
996 printf("bdg_forward: sorry, m_copypacket failed!\n");
997 return m0 ; /* the original is still there... */
1000 if (ifq_is_enabled(&last->if_snd)) {
1001 uint16_t ether_type;
1005 * If the queueing discipline needs packet classification,
1006 * do it before prepending link headers.
1008 ether_type = ntohs(eh->ether_type);
1009 if (ether_type == ETHERTYPE_IP)
1012 else if (ether_type == ETHERTYPE_IPV6)
1017 ifq_classify(&last->if_snd, m, af, &pktattr);
1021 * Add header (optimized for the common case of eh pointing
1022 * already into the mbuf) and execute last part of ether_output:
1023 * queue pkt and start output if interface not yet active.
1025 if ( (void *)(eh + 1) == (void *)m->m_data) {
1026 m->m_data -= ETHER_HDR_LEN ;
1027 m->m_len += ETHER_HDR_LEN ;
1028 m->m_pkthdr.len += ETHER_HDR_LEN ;
1031 M_PREPEND(m, ETHER_HDR_LEN, MB_DONTWAIT);
1033 printf("M_PREPEND failed\n");
1036 bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
1038 error = ifq_handoff(last, m, &pktattr);
1041 BDG_MUTE(last); /* should I also mute ? */
1044 BDG_STAT(last, BDG_OUT);
1052 * If the interface is used for bridging, not muted, not full,
1053 * up and running, is not the source interface, and belongs to
1054 * the same cluster as the 'real_dst', then send here.
1056 if ( BDG_USED(ifp) && !BDG_MUTED(ifp) &&
1058 !IF_QFULL(&ifp->if_snd) &&
1060 (ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING) &&
1061 ifp != src && BDG_SAMECLUSTER(ifp, real_dst) )
1063 ifp = TAILQ_NEXT(ifp, if_link) ;
1067 DEB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;
1068 if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; )
1073 * initialization of bridge code.
1078 printf("BRIDGE 020214 loaded\n");
1080 ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
1081 M_IFADDR, M_WAITOK | M_ZERO );
1085 callout_init(&bdg_timeout_h);
1087 bridge_in_ptr = bridge_in;
1088 bdg_forward_ptr = bdg_forward;
1089 bdgtakeifaces_ptr = reconfigure_bridge;
1095 bzero(&bdg_stats, sizeof(bdg_stats) );
1096 bdgtakeifaces_ptr();
1102 * initialization code, both for static and dynamic loading.
1105 bridge_modevent(module_t mod, int type, void *unused)
1120 #if !defined(KLD_MODULE)
1121 printf("bridge statically compiled, cannot unload\n");
1126 bridge_in_ptr = NULL;
1127 bdg_forward_ptr = NULL;
1128 bdgtakeifaces_ptr = NULL;
1129 callout_stop(&bdg_timeout_h);
1132 free(clusters, M_IFADDR);
1133 free(ifp2sc, M_IFADDR);
1145 static moduledata_t bridge_mod = {
1151 DECLARE_MODULE(bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
1152 MODULE_VERSION(bridge, 1);