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HardenedBSD/sys/net/bridge.c

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/*
* Copyright (c) 1998-2001 Luigi Rizzo
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* This code implements bridging in FreeBSD. It only acts on ethernet
* type of interfaces (others are still usable for routing).
* A bridging table holds the source MAC address/dest. interface for each
* known node. The table is indexed using an hash of the source address.
*
* Input packets are tapped near the beginning of ether_input(), and
* analysed by calling 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 calling bridge_dst_lookup(),
* and then forwarding is done using bdg_forward().
* Bridging is controlled by the sysctl variable net.link.ether.bridge
*
* 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. In the final release, unmuting will only occur
* because of explicit action of the user-level daemon.
*
* 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 is supposed to have addresses set (but
* there are no problems in practice if you set addresses 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.
* - loop detection is still not very robust.
* - the interface of bdg_forward() could be improved.
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/malloc.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/sysctl.h>
#include <net/if.h>
#include <net/if_types.h>
#include <netinet/in.h> /* for struct arpcom */
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h> /* for struct arpcom */
#include <net/route.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_dummynet.h>
#include <net/bridge.h>
static struct ifnet *bridge_in(struct ifnet *, struct ether_header *);
static struct mbuf *bdg_forward(struct mbuf *,
struct ether_header *const, struct ifnet *);
static void bdgtakeifaces(void);
/*
* For debugging, you can use the following macros.
* remember, rdtsc() only works on Pentium-class machines
quad_t ticks;
DDB(ticks = rdtsc();)
... interesting code ...
DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;)
*
*/
#define DDB(x) x
#define DEB(x)
static int bdginit(void);
static void flush_table(void);
static void bdg_promisc_on(void);
static void parse_bdg_cfg(void);
static int bdg_ipfw = 0 ;
static bdg_hash_table *bdg_table = NULL ;
static char *bdg_dst_names[] = {
"BDG_NULL ",
"BDG_BCAST ",
"BDG_MCAST ",
"BDG_LOCAL ",
"BDG_DROP ",
"BDG_UNKNOWN ",
"BDG_IN ",
"BDG_OUT ",
"BDG_FORWARD " };
/*
* System initialization
*/
static struct bdg_stats bdg_stats ;
static struct callout_handle bdg_timeout_h ;
#define IFP_CHK(ifp, x) \
if (ifp2sc[ifp->if_index].magic != 0xDEADBEEF) { x ; }
/*
* 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 ifnet *dst ;
int index ;
bdg_addr *p ;
if (IS_ETHER_BROADCAST(eh->ether_dhost))
return BDG_BCAST ;
if (eh->ether_dhost[0] & 1)
return BDG_MCAST ;
/*
* Lookup local addresses in case one matches.
*/
for (index = bdg_ports, p = bdg_addresses ; index ; index--, p++ )
if (BDG_MATCH(p->etheraddr, eh->ether_dhost) )
return BDG_LOCAL ;
/*
* Look for a possible destination in table
*/
index= HASH_FN( eh->ether_dhost );
dst = bdg_table[index].name;
if ( dst && BDG_MATCH( bdg_table[index].etheraddr, eh->ether_dhost) )
return dst ;
else
return BDG_UNKNOWN ;
}
/*
* turn off promisc mode, optionally clear the IFF_USED flag.
* The flag is turned on by parse_bdg_config
*/
static void
bdg_promisc_off(int clear_used)
{
struct ifnet *ifp ;
TAILQ_FOREACH(ifp, &ifnet, if_link) {
if ( (ifp2sc[ifp->if_index].flags & IFF_BDG_PROMISC) ) {
int s, ret ;
s = splimp();
ret = ifpromisc(ifp, 0);
splx(s);
ifp2sc[ifp->if_index].flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
DEB(printf(">> now %s%d promisc OFF if_flags 0x%x bdg_flags 0x%x\n",
ifp->if_name, ifp->if_unit,
ifp->if_flags, ifp2sc[ifp->if_index].flags);)
}
if (clear_used) {
ifp2sc[ifp->if_index].flags &= ~(IFF_USED) ;
bdg_stats.s[ifp->if_index].name[0] = '\0';
}
}
}
/*
* set promisc mode on the interfaces we use.
*/
static void
bdg_promisc_on()
{
struct ifnet *ifp ;
int s ;
TAILQ_FOREACH(ifp, &ifnet, if_link) {
if ( !BDG_USED(ifp) )
continue ;
if ( 0 == ( ifp->if_flags & IFF_UP) ) {
s = splimp();
if_up(ifp);
splx(s);
}
if ( !(ifp2sc[ifp->if_index].flags & IFF_BDG_PROMISC) ) {
int ret ;
s = splimp();
ret = ifpromisc(ifp, 1);
splx(s);
ifp2sc[ifp->if_index].flags |= IFF_BDG_PROMISC ;
printf(">> now %s%d promisc ON if_flags 0x%x bdg_flags 0x%x\n",
ifp->if_name, ifp->if_unit,
ifp->if_flags, ifp2sc[ifp->if_index].flags);
}
if (BDG_MUTED(ifp)) {
printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);
BDG_UNMUTE(ifp) ;
}
}
}
static int
sysctl_bdg(SYSCTL_HANDLER_ARGS)
{
int error, oldval = do_bridge ;
error = sysctl_handle_int(oidp,
oidp->oid_arg1, oidp->oid_arg2, req);
DEB( printf("called sysctl for bridge name %s arg2 %d val %d->%d\n",
oidp->oid_name, oidp->oid_arg2,
oldval, do_bridge); )
if (oldval != do_bridge) {
bdg_promisc_off( 1 ); /* reset previously used interfaces */
flush_table();
if (do_bridge) {
parse_bdg_cfg();
bdg_promisc_on();
}
}
return error ;
}
static char bridge_cfg[256] = { "" } ;
/*
* 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").
*/
static void
parse_bdg_cfg()
{
char *p, *beg ;
int i, l, cluster;
struct bdg_softc *b;
static char *sep = ", \t";
for (p = bridge_cfg; *p ; p++) {
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);
/*
* now search in bridge strings
*/
for (i=0, b = ifp2sc ; i < if_index ; i++, b++) {
char buf[32];
struct ifnet *ifp = b->ifp ;
if (ifp == NULL)
continue;
sprintf(buf, "%s%d", ifp->if_name, ifp->if_unit);
if (!strncmp(beg, buf, l)) {
b->cluster_id = htons(cluster) ;
b->flags |= IFF_USED ;
sprintf(bdg_stats.s[ifp->if_index].name,
"%s%d:%d", ifp->if_name, ifp->if_unit, cluster);
DEB(printf("--++ found %s\n",
bdg_stats.s[ifp->if_index].name);)
break ;
}
}
}
}
static int
sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
{
int error = 0 ;
char oldval[256] ;
strcpy(oldval, bridge_cfg) ;
error = sysctl_handle_string(oidp,
bridge_cfg, oidp->oid_arg2, req);
DEB(
printf("called sysctl for bridge name %s arg2 %d err %d val %s->%s\n",
oidp->oid_name, oidp->oid_arg2,
error,
oldval, bridge_cfg);
)
if (strcmp(oldval, bridge_cfg)) {
bdg_promisc_off( 1 ); /* reset previously-used interfaces */
flush_table();
parse_bdg_cfg(); /* and set new ones... */
if (do_bridge)
bdg_promisc_on(); /* re-enable interfaces */
}
return error ;
}
static int
sysctl_refresh(SYSCTL_HANDLER_ARGS)
{
if (req->newptr)
bdgtakeifaces();
return 0;
}
SYSCTL_DECL(_net_link_ether);
SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_cfg, CTLTYPE_STRING|CTLFLAG_RW,
&bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
"Bridge configuration");
SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge, CTLTYPE_INT|CTLFLAG_RW,
&do_bridge, 0, &sysctl_bdg, "I", "Bridging");
SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
&bdg_ipfw,0,"Pass bridged pkts through firewall");
/*
* The follow macro declares a variable, and maps it to
* a SYSCTL_INT entry with the same name.
*/
#define SY(parent, var, comment) \
static int var ; \
SYSCTL_INT(parent, OID_AUTO, var, CTLFLAG_RW, &(var), 0, comment);
int bdg_ipfw_drops;
SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_drop,
CTLFLAG_RW, &bdg_ipfw_drops,0,"");
int bdg_ipfw_colls;
SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_collisions,
CTLFLAG_RW, &bdg_ipfw_colls,0,"");
SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_refresh, CTLTYPE_INT|CTLFLAG_WR,
NULL, 0, &sysctl_refresh, "I", "iface refresh");
#if 1 /* diagnostic vars */
SY(_net_link_ether, verbose, "Be verbose");
SY(_net_link_ether, bdg_split_pkts, "Packets split in bdg_forward");
SY(_net_link_ether, bdg_thru, "Packets through bridge");
SY(_net_link_ether, bdg_copied, "Packets copied in bdg_forward");
SY(_net_link_ether, bdg_copy, "Force copy in bdg_forward");
SY(_net_link_ether, bdg_predict, "Correctly predicted header location");
SY(_net_link_ether, bdg_fw_avg, "Cycle counter avg");
SY(_net_link_ether, bdg_fw_ticks, "Cycle counter item");
SY(_net_link_ether, bdg_fw_count, "Cycle counter count");
#endif
SYSCTL_STRUCT(_net_link_ether, PF_BDG, bdgstats,
CTLFLAG_RD, &bdg_stats , bdg_stats, "bridge statistics");
static int bdg_loops ;
/*
* completely flush the bridge table.
*/
static void
flush_table()
{
int s,i;
s = splimp();
for (i=0; i< HASH_SIZE; i++)
bdg_table[i].name= NULL; /* clear table */
splx(s);
}
/*
* called periodically to flush entries etc.
*/
static void
bdg_timeout(void *dummy)
{
static int slowtimer = 0 ;
if (do_bridge) {
static int age_index = 0 ; /* index of table position to age */
int l = age_index + HASH_SIZE/4 ;
/*
* age entries in the forwarding table.
*/
if (l > HASH_SIZE)
l = HASH_SIZE ;
for (; age_index < l ; age_index++)
if (bdg_table[age_index].used)
bdg_table[age_index].used = 0 ;
else if (bdg_table[age_index].name) {
/* printf("xx flushing stale entry %d\n", age_index); */
bdg_table[age_index].name = NULL ;
}
if (age_index >= HASH_SIZE)
age_index = 0 ;
if (--slowtimer <= 0 ) {
slowtimer = 5 ;
bdg_promisc_on() ; /* we just need unmute, really */
bdg_loops = 0 ;
}
}
bdg_timeout_h = timeout(bdg_timeout, NULL, 2*hz );
}
/*
* local MAC addresses are held in a small array. This makes comparisons
* much faster.
*/
bdg_addr bdg_addresses[BDG_MAX_PORTS];
static int bdg_ports ;
static int bdg_max_ports = BDG_MAX_PORTS ;
/*
* initialization of bridge code. This needs to be done after all
* interfaces have been configured.
*/
static int
bdginit(void)
{
bdg_table = (struct hash_table *)
malloc(HASH_SIZE * sizeof(struct hash_table),
M_IFADDR, M_WAITOK | M_ZERO);
if (bdg_table == NULL)
return ENOMEM;
ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
M_IFADDR, M_WAITOK | M_ZERO );
if (ifp2sc == NULL) {
free(bdg_table, M_IFADDR);
bdg_table = NULL ;
return ENOMEM ;
}
bridge_in_ptr = bridge_in;
bdg_forward_ptr = bdg_forward;
bdgtakeifaces_ptr = bdgtakeifaces;
flush_table();
bzero(&bdg_stats, sizeof(bdg_stats) );
bdgtakeifaces();
bdg_timeout(0);
do_bridge=0;
return 0 ;
}
/**
* fetch interfaces that can do bridging.
* This is re-done every time we attach or detach an interface.
*/
static void
bdgtakeifaces(void)
{
struct ifnet *ifp;
struct arpcom *ac ;
bdg_addr *p = bdg_addresses ;
struct bdg_softc *bp;
bdg_ports = 0 ;
*bridge_cfg = '\0';
printf("BRIDGE 011031, have %d interfaces\n", if_index);
TAILQ_FOREACH(ifp, &ifnet, if_link)
if (ifp->if_type == IFT_ETHER) { /* ethernet ? */
/*
* XXX should try to grow the arrays as needed.
*/
bp = &ifp2sc[ifp->if_index] ;
ac = (struct arpcom *)ifp;
sprintf(bridge_cfg + strlen(bridge_cfg),
"%s%d:1,", ifp->if_name, ifp->if_unit);
printf("-- index %d %s type %d phy %d addrl %d addr %6D\n",
ifp->if_index,
bdg_stats.s[ifp->if_index].name,
(int)ifp->if_type, (int) ifp->if_physical,
(int)ifp->if_addrlen,
ac->ac_enaddr, "." );
bcopy(ac->ac_enaddr, p->etheraddr, 6);
p++ ;
bp->ifp = ifp ;
bp->flags = IFF_USED ;
bp->cluster_id = htons(1) ;
bp->magic = 0xDEADBEEF ;
sprintf(bdg_stats.s[ifp->if_index].name,
"%s%d:%d", ifp->if_name, ifp->if_unit,
ntohs(bp->cluster_id));
bdg_ports ++ ;
}
}
/**
* bridge_in() is invoked to perform bridging decision on input packets.
*
* On Input:
* eh Ethernet header of the incoming packet. We only need this.
*
* 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 ;
int dropit = BDG_MUTED(ifp) ;
/*
* hash the source address
*/
index= HASH_FN(eh->ether_shost);
bdg_table[index].used = 1 ;
old = bdg_table[index].name ;
if ( old ) { /* the entry is valid. */
IFP_CHK(old, printf("bridge_in-- reading table\n") );
if (!BDG_MATCH( eh->ether_shost, bdg_table[index].etheraddr) ) {
bdg_ipfw_colls++ ;
bdg_table[index].name = NULL ;
} else if (old != ifp) {
/*
* Found a loop. Either a machine has moved, or there
* is a misconfiguration/reconfiguration of the network.
* First, do not forward this packet!
* Record the relocation anyways; then, if loops persist,
* suspect a reconfiguration and disable forwarding
* from the old interface.
*/
bdg_table[index].name = ifp ; /* relocate address */
printf("-- loop (%d) %6D to %s%d from %s%d (%s)\n",
bdg_loops, eh->ether_shost, ".",
ifp->if_name, ifp->if_unit,
old->if_name, old->if_unit,
BDG_MUTED(old) ? "muted":"active");
dropit = 1 ;
if ( !BDG_MUTED(old) ) {
if (++bdg_loops > 10)
BDG_MUTE(old) ;
}
}
}
/*
* now write the source address into the table
*/
if (bdg_table[index].name == NULL) {
DEB(printf("new addr %6D at %d for %s%d\n",
eh->ether_shost, ".", index, ifp->if_name, ifp->if_unit);)
bcopy(eh->ether_shost, bdg_table[index].etheraddr, 6);
bdg_table[index].name = ifp ;
}
dst = bridge_dst_lookup(eh);
/*
* bridge_dst_lookup can return the following values:
* BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp.
* For muted interfaces, or when we detect a loop, the first 3 are
* changed in BDG_LOCAL (we still listen to incoming traffic),
* and others to BDG_DROP (no use for the local host).
* Also, for incoming packets, ifp is changed to BDG_DROP if ifp == src.
* These changes are not necessary for outgoing packets from ether_output().
*/
BDG_STAT(ifp, BDG_IN);
switch ((uintptr_t)dst) {
case (uintptr_t) BDG_BCAST:
case (uintptr_t) BDG_MCAST:
case (uintptr_t) BDG_LOCAL:
case (uintptr_t) BDG_UNKNOWN:
case (uintptr_t) BDG_DROP:
BDG_STAT(ifp, dst);
break ;
default :
if (dst == ifp || dropit)
BDG_STAT(ifp, BDG_DROP);
else
BDG_STAT(ifp, BDG_FORWARD);
break ;
}
if ( dropit ) {
if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_LOCAL)
dst = BDG_LOCAL ;
else
dst = BDG_DROP ;
} else {
if (dst == ifp)
dst = BDG_DROP;
}
DEB(printf("bridge_in %6D ->%6D ty 0x%04x dst %s%d\n",
eh->ether_shost, ".",
eh->ether_dhost, ".",
ntohs(eh->ether_type),
(dst <= BDG_FORWARD) ? bdg_dst_names[(int)dst] :
dst->if_name,
(dst <= BDG_FORWARD) ? 0 : dst->if_unit); )
return dst ;
}
/*
* Forward a packet to dst -- which can be a single interface or
* an entire cluster. The src port and muted interfaces are excluded.
*
* If src == NULL, the pkt comes from ether_output, and dst is the real
* interface the packet is originally sent to. In this case, we must forward
* it to the whole cluster.
* We never call bdg_forward from ether_output on interfaces which are
* not part of a cluster.
*
* If possible (i.e. we can determine that the caller does not need
* a copy), the packet is consumed here, and bdg_forward returns NULL.
* Otherwise, a pointer to a copy of the packet is returned.
*
* XXX be careful with eh, it can be a pointer into *m
*/
static struct mbuf *
bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
{
struct ifnet *src = m0->m_pkthdr.rcvif; /* NULL when called by *_output */
struct ifnet *ifp, *last = NULL ;
int shared = bdg_copy ; /* someone else is using the mbuf */
int once = 0; /* loop only once */
struct ifnet *real_dst = dst ; /* real dst from ether_output */
struct ip_fw *rule = NULL ; /* did we match a firewall rule ? */
/*
* XXX eh is usually a pointer within the mbuf (some ethernet drivers
* do that), so we better copy it before doing anything with the mbuf,
* or we might corrupt the header.
*/
struct ether_header save_eh = *eh ;
DEB(quad_t ticks; ticks = rdtsc();)
if (m0->m_type == MT_DUMMYNET) {
/* extract info from dummynet header */
rule = (struct ip_fw *)(m0->m_data) ;
m0 = m0->m_next ;
src = m0->m_pkthdr.rcvif;
shared = 0 ; /* For sure this is our own mbuf. */
} else
bdg_thru++; /* count packet, only once */
if (src == NULL) /* packet from ether_output */
dst = bridge_dst_lookup(eh);
if (dst == BDG_DROP) { /* this should not happen */
printf("xx bdg_forward for BDG_DROP\n");
m_freem(m0);
return NULL;
}
if (dst == BDG_LOCAL) { /* this should not happen as well */
printf("xx ouch, bdg_forward for local pkt\n");
return m0;
}
if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
ifp = TAILQ_FIRST(&ifnet) ; /* scan all ports */
once = 0 ;
if (dst != BDG_UNKNOWN) /* need a copy for the local stack */
shared = 1 ;
} else {
ifp = dst ;
once = 1 ;
}
if (ifp <= BDG_FORWARD)
panic("bdg_forward: bad dst");
/*
* Do filtering in a very similar way to what is done in ip_output.
* Only if firewall is loaded, enabled, and the packet is not
* from ether_output() (src==NULL, or we would filter it twice).
* Additional restrictions may apply e.g. non-IP, short packets,
* and pkts already gone through a pipe.
*/
if (IPFW_LOADED && bdg_ipfw != 0 && src != NULL) {
struct ip *ip ;
int i;
if (rule != NULL) /* dummynet packet, already partially processed */
goto forward; /* HACK! I should obey the fw_one_pass */
if (ntohs(save_eh.ether_type) != ETHERTYPE_IP)
goto forward ; /* not an IP packet, ipfw is not appropriate */
if (m0->m_pkthdr.len < sizeof(struct ip) )
goto forward ; /* header too short for an IP pkt, cannot filter */
/*
* i need some amt of data to be contiguous, and in case others need
* the packet (shared==1) also better be in the first mbuf.
*/
i = min(m0->m_pkthdr.len, max_protohdr) ;
if ( shared || m0->m_len < i) {
m0 = m_pullup(m0, i) ;
if (m0 == NULL) {
printf("-- bdg: pullup failed.\n") ;
return NULL ;
}
}
/*
* 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
*/
ip = mtod(m0, struct ip *);
NTOHS(ip->ip_len);
NTOHS(ip->ip_off);
/*
* The third parameter to the firewall code is the dst. interface.
* Since we apply checks only on input pkts we use NULL.
* The firewall knows this is a bridged packet as the cookie ptr
* is NULL.
*/
i = ip_fw_chk_ptr(&ip, 0, NULL, NULL /* cookie */, &m0, &rule, NULL);
if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */
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 *);
HTONS(ip->ip_len);
HTONS(ip->ip_off);
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.
* Need to prepend the ethernet header, optimize the common
* case of eh pointing already into the original mbuf.
*/
struct mbuf *m ;
if (shared) {
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) {
printf("bdg_fwd: copy(1) failed\n");
return m0;
}
} else {
m = m0 ; /* pass the original to dummynet */
m0 = NULL ; /* and nothing back to the caller */
}
if ( (void *)(eh + 1) == (void *)m->m_data) {
m->m_data -= ETHER_HDR_LEN ;
m->m_len += ETHER_HDR_LEN ;
m->m_pkthdr.len += ETHER_HDR_LEN ;
bdg_predict++;
} else {
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
if (!m && verbose)
printf("M_PREPEND failed\n");
if (m == NULL) /* nope... */
return m0 ;
bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
}
ip_dn_io_ptr((i & 0xffff),DN_TO_BDG_FWD,m,real_dst,NULL,0,rule,0);
return m0 ;
}
/*
* XXX add divert/forward actions...
*/
/* if none of the above matches, we have to drop the pkt */
bdg_ipfw_drops++ ;
printf("bdg_forward: No rules match, so dropping packet!\n");
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) {
printf("-- bdg: pullup2 failed.\n") ;
return NULL ;
}
}
/* now real_dst is used to determine the cluster where to forward */
if (src != NULL) /* pkt comes from ether_input */
real_dst = src ;
for (;;) {
if (last) { /* need to forward packet leftover from previous loop */
struct mbuf *m ;
if (shared == 0 && once ) { /* no need to copy */
m = m0 ;
m0 = NULL ; /* original is gone */
} else {
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) {
printf("bdg_forward: sorry, m_copypacket failed!\n");
return m0 ; /* the original is still there... */
}
}
/*
* Add header (optimized for the common case of eh pointing
* already into the mbuf) and execute last part of ether_output:
* queue pkt and start output if interface not yet active.
*/
if ( (void *)(eh + 1) == (void *)m->m_data) {
m->m_data -= ETHER_HDR_LEN ;
m->m_len += ETHER_HDR_LEN ;
m->m_pkthdr.len += ETHER_HDR_LEN ;
bdg_predict++;
} else {
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
if (!m && verbose)
printf("M_PREPEND failed\n");
if (m == NULL)
return m0;
bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
}
if (! IF_HANDOFF(&last->if_snd, m, last)) {
#if 0
BDG_MUTE(last); /* should I also mute ? */
#endif
}
BDG_STAT(last, BDG_OUT);
last = NULL ;
if (once)
break ;
}
if (ifp == NULL)
break ;
/*
* If the interface is used for bridging, not muted, not full,
* up and running, is not the source interface, and belongs to
* the same cluster as the 'real_dst', then send here.
*/
if ( BDG_USED(ifp) && !BDG_MUTED(ifp) && !_IF_QFULL(&ifp->if_snd) &&
(ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING) &&
ifp != src && BDG_SAMECLUSTER(ifp, real_dst) )
last = ifp ;
ifp = TAILQ_NEXT(ifp, if_link) ;
if (ifp == NULL)
once = 1 ;
}
DEB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;
if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; )
return m0 ;
}
/*
* initialization code, both for static and dynamic loading.
*/
static int
bridge_modevent(module_t mod, int type, void *unused)
{
int s;
int err;
switch (type) {
case MOD_LOAD:
if (BDG_LOADED) {
err = EEXIST;
break ;
}
s = splimp();
err = bdginit();
splx(s);
break;
case MOD_UNLOAD:
#if !defined(KLD_MODULE)
printf("bridge statically compiled, cannot unload\n");
err = EINVAL ;
#else
s = splimp();
do_bridge = 0;
bridge_in_ptr = NULL;
bdg_forward_ptr = NULL;
bdgtakeifaces_ptr = NULL;
untimeout(bdg_timeout, NULL, bdg_timeout_h);
free(bdg_table, M_IFADDR);
bdg_table = NULL ;
free(ifp2sc, M_IFADDR);
ifp2sc = NULL ;
splx(s);
#endif
break;
default:
err = EINVAL ;
break;
}
return err;
}
static moduledata_t bridge_mod = {
"bridge",
bridge_modevent,
0
};
DECLARE_MODULE(bridge, bridge_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(bridge, 1);
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