FreeBSD-5.3/sys/net/bridge.c
/*
* 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: src/sys/net/bridge.c,v 1.82.2.2 2004/10/03 17:04:39 mlaier Exp $
*/
/*
* 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.enable
* the grouping of interfaces into clusters is done with
* net.link.ether.bridge.config
* 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.config="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 <sys/param.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/protosw.h>
#include <sys/systm.h>
#include <sys/socket.h> /* for net/if.h */
#include <sys/ctype.h> /* string functions */
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h> /* for struct arpcom */
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <net/route.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_dummynet.h>
#include <net/bridge.h>
/*--------------------*/
#define ETHER_ADDR_COPY(_dst,_src) bcopy(_src, _dst, ETHER_ADDR_LEN)
#define ETHER_ADDR_EQ(_a1,_a2) (bcmp(_a1, _a2, ETHER_ADDR_LEN) == 0)
/*
* 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[ETHER_ADDR_LEN];
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[ETHER_ADDR_LEN];
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 */
static int n_clusters; /* number of clusters */
static struct cluster_softc *clusters;
static struct mtx bdg_mtx;
#define BDG_LOCK_INIT() mtx_init(&bdg_mtx, "bridge", NULL, MTX_DEF)
#define BDG_LOCK_DESTROY() mtx_destroy(&bdg_mtx)
#define BDG_LOCK() mtx_lock(&bdg_mtx)
#define BDG_UNLOCK() mtx_unlock(&bdg_mtx)
#define BDG_LOCK_ASSERT() mtx_assert(&bdg_mtx, MA_OWNED)
#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) ETHER_ADDR_EQ(a,b)
#define IS_ETHER_BROADCAST(a) ETHER_ADDR_EQ(a,"\377\377\377\377\377\377")
#endif
SYSCTL_DECL(_net_link_ether);
SYSCTL_NODE(_net_link_ether, OID_AUTO, bridge, CTLFLAG_RD, 0,
"Bridge parameters");
static char bridge_version[] = "031224";
SYSCTL_STRING(_net_link_ether_bridge, OID_AUTO, version, CTLFLAG_RD,
bridge_version, 0, "software version");
#define BRIDGE_DEBUG
#ifdef BRIDGE_DEBUG
int bridge_debug = 0;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, debug, CTLFLAG_RW, &bridge_debug,
0, "control debugging printfs");
#define DPRINTF(X) if (bridge_debug) printf X
#else
#define DPRINTF(X)
#endif
#ifdef BRIDGE_TIMING
/*
* 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
static int bdg_fw_avg;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_avg, CTLFLAG_RW,
&bdg_fw_avg, 0,"Cycle counter avg");
static int bdg_fw_ticks;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_ticks, CTLFLAG_RW,
&bdg_fw_ticks, 0,"Cycle counter item");
static int bdg_fw_count;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_count, CTLFLAG_RW,
&bdg_fw_count, 0,"Cycle counter count");
#else
#define DDB(x)
#endif
static int bdginit(void);
static void parse_bdg_cfg(void);
static int bdg_ipf; /* IPFilter enabled in bridge */
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipf, CTLFLAG_RW,
&bdg_ipf, 0,"Pass bridged pkts through IPFilter");
static int bdg_ipfw;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw, CTLFLAG_RW,
&bdg_ipfw,0,"Pass bridged pkts through firewall");
static int bdg_copy;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, copy, CTLFLAG_RW,
&bdg_copy, 0, "Force packet copy in bdg_forward");
int bdg_ipfw_drops;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw_drop,
CTLFLAG_RW, &bdg_ipfw_drops,0,"");
int bdg_ipfw_colls;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipfw_collisions,
CTLFLAG_RW, &bdg_ipfw_colls,0,"");
static int bdg_thru;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, packets, CTLFLAG_RW,
&bdg_thru, 0, "Packets through bridge");
static int bdg_dropped;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, dropped, CTLFLAG_RW,
&bdg_dropped, 0, "Packets dropped in bdg_forward");
static int bdg_predict;
SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, predict, CTLFLAG_RW,
&bdg_predict, 0, "Correctly predicted header location");
#ifdef BRIDGE_DEBUG
static char *bdg_dst_names[] = {
"BDG_NULL ",
"BDG_BCAST ",
"BDG_MCAST ",
"BDG_LOCAL ",
"BDG_DROP ",
"BDG_UNKNOWN ",
"BDG_IN ",
"BDG_OUT ",
"BDG_FORWARD " };
#endif /* BRIDGE_DEBUG */
/*
* System initialization
*/
static struct bdg_stats bdg_stats ;
SYSCTL_STRUCT(_net_link_ether_bridge, OID_AUTO, stats, CTLFLAG_RD,
&bdg_stats, bdg_stats, "bridge statistics");
static struct callout bdg_callout;
/*
* 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 ifnet *ifp)
{
struct cluster_softc *c = NULL;
int i;
BDG_LOCK_ASSERT();
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_NOWAIT | M_ZERO);
if (c == NULL) {/* malloc failure */
printf("-- bridge: cannot add new cluster\n");
goto bad;
}
c[n_clusters].ht = (struct hash_table *)
malloc(HASH_SIZE * sizeof(struct hash_table),
M_IFADDR, M_NOWAIT | M_ZERO);
if (c[n_clusters].ht == NULL) {
printf("-- bridge: cannot allocate hash table for new cluster\n");
goto bad;
}
c[n_clusters].my_macs = (struct bdg_addr *)
malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr),
M_IFADDR, M_NOWAIT | 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);
goto bad;
}
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 ... */
ETHER_ADDR_COPY(c->my_macs[c->ports].etheraddr, IFP2AC(ifp)->ac_enaddr);
c->ports++;
return c;
bad:
if (c)
free(c, M_IFADDR);
return NULL;
}
/*
* 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;
BDG_LOCK_ASSERT();
DPRINTF(("%s: n_clusters %d\n", __func__, n_clusters));
IFNET_RLOCK();
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 ) {
ifpromisc(ifp, 0);
b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
DPRINTF(("%s: %s promisc OFF if_flags 0x%x "
"bdg_flags 0x%x\n", __func__, ifp->if_xname,
ifp->if_flags, b->flags));
}
b->flags &= ~(IFF_USED) ;
b->cluster = NULL;
bdg_stats.s[ifp->if_index].name[0] = '\0';
}
IFNET_RUNLOCK();
/* flush_tables */
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;
}
/*
* set promisc mode on the interfaces we use.
*/
static void
bridge_on(void)
{
struct ifnet *ifp ;
BDG_LOCK_ASSERT();
IFNET_RLOCK();
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) ) {
if_up(ifp);
}
if ( !(b->flags & IFF_BDG_PROMISC) ) {
(void) ifpromisc(ifp, 1);
b->flags |= IFF_BDG_PROMISC ;
DPRINTF(("%s: %s promisc ON if_flags 0x%x bdg_flags 0x%x\n",
__func__, ifp->if_xname, ifp->if_flags, b->flags));
}
if (b->flags & IFF_MUTE) {
DPRINTF(("%s: unmuting %s\n", __func__, ifp->if_xname));
b->flags &= ~IFF_MUTE;
}
}
IFNET_RUNLOCK();
}
static char bridge_cfg[1024]; /* NB: in BSS so initialized to zero */
/**
* 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_locked(void)
{
BDG_LOCK_ASSERT();
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 void
reconfigure_bridge(void)
{
BDG_LOCK();
reconfigure_bridge_locked();
BDG_UNLOCK();
}
/*
* 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(void)
{
char *p, *beg;
int l, cluster;
static const char *sep = ", \t";
BDG_LOCK_ASSERT();
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
*/
IFNET_RLOCK(); /* could sleep XXX */
TAILQ_FOREACH(ifp, &ifnet, if_link) {
if (!strncmp(beg, ifp->if_xname, max(l, strlen(ifp->if_xname)))) {
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", ifp->if_xname);
continue;
}
if (b->flags & IFF_USED) {
printf("%s already used, skipping\n", ifp->if_xname);
break;
}
b->cluster = add_cluster(htons(cluster), ifp);
b->flags |= IFF_USED ;
snprintf(bdg_stats.s[ifp->if_index].name,
sizeof(bdg_stats.s[ifp->if_index].name),
"%s:%d", ifp->if_xname, cluster);
DPRINTF(("%s: found %s next c %d\n", __func__,
bdg_stats.s[ifp->if_index].name, c));
found = 1;
break ;
}
}
IFNET_RUNLOCK();
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 enable = do_bridge;
int error;
error = sysctl_handle_int(oidp, &enable, 0, req);
enable = (enable) ? 1 : 0;
BDG_LOCK();
if (enable != do_bridge) {
do_bridge = enable;
reconfigure_bridge_locked();
}
BDG_UNLOCK();
return error ;
}
SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, enable, CTLTYPE_INT|CTLFLAG_RW,
&do_bridge, 0, &sysctl_bdg, "I", "Bridging");
/*
* handler for net.link.ether.bridge_cfg
*/
static int
sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
{
int error;
char *new_cfg;
new_cfg = malloc(sizeof(bridge_cfg), M_TEMP, M_WAITOK);
bcopy(bridge_cfg, new_cfg, sizeof(bridge_cfg));
error = sysctl_handle_string(oidp, new_cfg, oidp->oid_arg2, req);
if (error == 0) {
BDG_LOCK();
if (strcmp(new_cfg, bridge_cfg)) {
bcopy(new_cfg, bridge_cfg, sizeof(bridge_cfg));
reconfigure_bridge_locked();
}
BDG_UNLOCK();
}
free(new_cfg, M_TEMP);
return error;
}
SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, config, CTLTYPE_STRING|CTLFLAG_RW,
&bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
"Bridge configuration");
static int
sysctl_refresh(SYSCTL_HANDLER_ARGS)
{
if (req->newptr)
reconfigure_bridge();
return 0;
}
SYSCTL_PROC(_net_link_ether_bridge, OID_AUTO, refresh, CTLTYPE_INT|CTLFLAG_WR,
NULL, 0, &sysctl_refresh, "I", "iface refresh");
#ifndef BURN_BRIDGES
#define SYSCTL_OID_COMPAT(parent, nbr, name, kind, a1, a2, handler, fmt, descr)\
static struct sysctl_oid sysctl__##parent##_##name##_compat = { \
&sysctl_##parent##_children, { 0 }, \
nbr, kind, a1, a2, #name, handler, fmt, 0, descr }; \
DATA_SET(sysctl_set, sysctl__##parent##_##name##_compat)
#define SYSCTL_INT_COMPAT(parent, nbr, name, access, ptr, val, descr) \
SYSCTL_OID_COMPAT(parent, nbr, name, CTLTYPE_INT|(access), \
ptr, val, sysctl_handle_int, "I", descr)
#define SYSCTL_STRUCT_COMPAT(parent, nbr, name, access, ptr, type, descr)\
SYSCTL_OID_COMPAT(parent, nbr, name, CTLTYPE_OPAQUE|(access), \
ptr, sizeof(struct type), sysctl_handle_opaque, \
"S," #type, descr)
#define SYSCTL_PROC_COMPAT(parent, nbr, name, access, ptr, arg, handler, fmt, descr) \
SYSCTL_OID_COMPAT(parent, nbr, name, (access), \
ptr, arg, handler, fmt, descr)
SYSCTL_INT_COMPAT(_net_link_ether, OID_AUTO, bridge_ipf, CTLFLAG_RW,
&bdg_ipf, 0,"Pass bridged pkts through IPFilter");
SYSCTL_INT_COMPAT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
&bdg_ipfw,0,"Pass bridged pkts through firewall");
SYSCTL_STRUCT_COMPAT(_net_link_ether, PF_BDG, bdgstats, CTLFLAG_RD,
&bdg_stats, bdg_stats, "bridge statistics");
SYSCTL_PROC_COMPAT(_net_link_ether, OID_AUTO, bridge_cfg,
CTLTYPE_STRING|CTLFLAG_RW,
&bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
"Bridge configuration");
SYSCTL_PROC_COMPAT(_net_link_ether, OID_AUTO, bridge_refresh,
CTLTYPE_INT|CTLFLAG_WR,
NULL, 0, &sysctl_refresh, "I", "iface refresh");
#endif
static int bdg_loops;
static int bdg_slowtimer = 0;
static int bdg_age_index = 0; /* index of table position to age */
/*
* called periodically to flush entries etc.
*/
static void
bdg_timeout(void *dummy)
{
if (do_bridge) {
int l, i;
BDG_LOCK();
/*
* age entries in the forwarding table.
*/
l = bdg_age_index + HASH_SIZE/4 ;
if (l > HASH_SIZE)
l = HASH_SIZE;
for (i = 0; i < n_clusters; i++) {
bdg_hash_table *bdg_table = clusters[i].ht;
for (; bdg_age_index < l; bdg_age_index++)
if (bdg_table[bdg_age_index].used)
bdg_table[bdg_age_index].used = 0;
else if (bdg_table[bdg_age_index].name) {
DPRINTF(("%s: flushing stale entry %d\n",
__func__, bdg_age_index));
bdg_table[bdg_age_index].name = NULL;
}
}
if (bdg_age_index >= HASH_SIZE)
bdg_age_index = 0;
if (--bdg_slowtimer <= 0 ) {
bdg_slowtimer = 5;
bridge_on(); /* we just need unmute, really */
bdg_loops = 0;
}
BDG_UNLOCK();
}
callout_reset(&bdg_callout, 2*hz, bdg_timeout, NULL);
}
/*
* 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)
{
bdg_hash_table *bt; /* pointer to entry in hash table */
BDG_LOCK_ASSERT();
if (ETHER_IS_MULTICAST(eh->ether_dhost))
return IS_ETHER_BROADCAST(eh->ether_dhost) ? BDG_BCAST : BDG_MCAST;
/*
* Lookup local addresses in case one matches. We optimize
* for the common case of two interfaces.
*/
KASSERT(c->ports != 0, ("lookup with no ports!"));
switch (c->ports) {
int i;
default:
for (i = c->ports-1; i > 1; i--) {
if (ETHER_ADDR_EQ(c->my_macs[i].etheraddr, eh->ether_dhost))
return BDG_LOCAL;
}
/* fall thru... */
case 2:
if (ETHER_ADDR_EQ(c->my_macs[1].etheraddr, eh->ether_dhost))
return BDG_LOCAL;
case 1:
if (ETHER_ADDR_EQ(c->my_macs[0].etheraddr, eh->ether_dhost))
return BDG_LOCAL;
}
/*
* Look for a possible destination in table
*/
bt = &c->ht[HASH_FN(eh->ether_dhost)];
if (bt->name && ETHER_ADDR_EQ(bt->etheraddr, eh->ether_dhost))
return bt->name;
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
*/
BDG_LOCK();
index = HASH_FN(eh->ether_shost);
bt = &BDG_CLUSTER(ifp)->ht[index];
bt->used = 1;
old = bt->name;
if (old) { /* the entry is valid */
if (!ETHER_ADDR_EQ(eh->ether_shost, bt->etheraddr)) {
bdg_ipfw_colls++;
bt->name = NULL; /* NB: will overwrite below */
} 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 from %s (%s)\n",
bdg_loops, eh->ether_shost, ".",
ifp->if_xname, old->if_xname,
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) {
DPRINTF(("%s: new addr %6D at %d for %s\n",
__func__, eh->ether_shost, ".", index, ifp->if_xname));
ETHER_ADDR_COPY(bt->etheraddr, eh->ether_shost);
bt->name = ifp;
}
dst = bridge_dst_lookup(eh, BDG_CLUSTER(ifp));
BDG_UNLOCK();
/*
* 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;
}
DPRINTF(("%s: %6D ->%6D ty 0x%04x dst %s\n", __func__,
eh->ether_shost, ".",
eh->ether_dhost, ".",
ntohs(eh->ether_type),
(dst <= BDG_FORWARD) ? bdg_dst_names[(uintptr_t)dst] :
dst->if_xname));
return dst;
}
/*
* Return 1 if it's ok to send a packet out the specified interface.
* The interface must be:
* used for bridging,
* not muted,
* not full,
* up and running,
* not the source interface, and
* belong to the same cluster as the 'real_dst'.
*/
static __inline int
bridge_ifok(struct ifnet *ifp, struct ifnet *src, struct ifnet *dst)
{
return (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, 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_DONTWAIT); \
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 error;
struct ifnet *real_dst = dst; /* real dst from ether_output */
struct ip_fw_args args;
struct ether_header save_eh;
struct mbuf *m;
DDB(quad_t ticks; ticks = rdtsc();)
args.rule = ip_dn_claim_rule(m0);
if (args.rule)
shared = 0; /* For sure this is our own mbuf. */
else
bdg_thru++; /* count 1st time through bdg_forward */
/*
* 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 */
BDG_LOCK();
dst = bridge_dst_lookup(eh, BDG_CLUSTER(real_dst));
BDG_UNLOCK();
}
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) {
/* need a copy for the local stack */
shared = 1;
}
/*
* 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 && (
(inet_pfil_hook.ph_busy_count >= 0 && bdg_ipf != 0) ||
(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("%s: m_pullup failed\n", __func__); /* XXXDPRINTF*/
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 */
/*
* NetBSD-style generic packet filter, pfil(9), hooks.
* Enables ipf(8) in bridging.
*/
if (!IPFW_LOADED) { /* XXX: Prevent ipfw from being run twice. */
if (inet_pfil_hook.ph_busy_count >= 0 &&
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);
if (pfil_run_hooks(&inet_pfil_hook, &m0, src, PFIL_IN, NULL) != 0) {
/* NB: hook should consume packet */
return NULL;
}
if (m0 == NULL) /* consumed by filter */
return m0;
/*
* 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);
}
} /* XXX: Prevent ipfw from being run twice. */
/*
* 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.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 */
if (m0 != NULL)
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.
*/
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;
if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
/*
* Scan all ports and send copies to all but the last.
*/
IFNET_RLOCK(); /* XXX replace with generation # */
TAILQ_FOREACH(ifp, &ifnet, if_link) {
if (bridge_ifok(ifp, src, real_dst)) {
if (last) {
/*
* At this point we know two interfaces need a copy
* of the packet (last + ifp) so we must create a
* copy to handoff to last.
*/
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) {
IFNET_RUNLOCK();
printf("%s: , m_copypacket failed!\n", __func__);
bdg_dropped++;
return m0; /* the original is still there... */
}
IFQ_HANDOFF(last, m, error);
if (!error)
BDG_STAT(last, BDG_OUT);
else
bdg_dropped++;
}
last = ifp;
}
}
IFNET_RUNLOCK();
} else {
if (bridge_ifok(dst, src, real_dst))
last = dst;
}
if (last) {
if (shared) { /* need to copy */
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) {
printf("%s: sorry, m_copypacket failed!\n", __func__);
bdg_dropped++ ;
return m0; /* the original is still there... */
}
} else { /* consume original */
m = m0, m0 = NULL;
}
IFQ_HANDOFF(last, m, error);
if (!error)
BDG_STAT(last, BDG_OUT);
else
bdg_dropped++;
}
DDB(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)
{
if (bootverbose)
printf("BRIDGE %s loaded\n", bridge_version);
ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
M_IFADDR, M_WAITOK | M_ZERO );
if (ifp2sc == NULL)
return ENOMEM;
BDG_LOCK_INIT();
n_clusters = 0;
clusters = NULL;
do_bridge = 0;
bzero(&bdg_stats, sizeof(bdg_stats));
bridge_in_ptr = bridge_in;
bdg_forward_ptr = bdg_forward;
bdgtakeifaces_ptr = reconfigure_bridge;
bdgtakeifaces_ptr(); /* XXX does this do anything? */
callout_init(&bdg_callout, debug_mpsafenet ? CALLOUT_MPSAFE : 0);
bdg_timeout(0);
return 0 ;
}
static void
bdgdestroy(void)
{
bridge_in_ptr = NULL;
bdg_forward_ptr = NULL;
bdgtakeifaces_ptr = NULL;
callout_stop(&bdg_callout);
BDG_LOCK();
bridge_off();
if (ifp2sc) {
free(ifp2sc, M_IFADDR);
ifp2sc = NULL;
}
BDG_LOCK_DESTROY();
}
/*
* initialization code, both for static and dynamic loading.
*/
static int
bridge_modevent(module_t mod, int type, void *unused)
{
int err;
switch (type) {
case MOD_LOAD:
if (BDG_LOADED)
err = EEXIST;
else
err = bdginit();
break;
case MOD_UNLOAD:
do_bridge = 0;
bdgdestroy();
err = 0;
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);