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freebsd-dev/sys/net/bridge.c

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/*
* Copyright (c) 1998-2000 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 bdg_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 requires some (small) modifications to the interface
* driver. Not all of them have been changed, see the "ed" and "de"
* drivers as examples on how to operate.
* - 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/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 "opt_ipfw.h"
#include "opt_ipdn.h"
#if defined(IPFIREWALL)
#include <net/route.h>
#include <netinet/ip_fw.h>
#if defined(DUMMYNET)
#include <netinet/ip_dummynet.h>
#endif
#endif
#include <net/bridge.h>
/*
* 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 void bdginit(void *);
static void bdgtakeifaces(void);
static void flush_table(void);
static void bdg_promisc_on(void);
static void parse_bdg_cfg(void);
static int bdg_ipfw = 0 ;
int do_bridge = 0;
bdg_hash_table *bdg_table = NULL ;
/*
* System initialization
*/
SYSINIT(interfaces, SI_SUB_PROTO_IF, SI_ORDER_FIRST, bdginit, NULL)
/*
* We need additional info for the bridge. The bdg_ifp2sc[] array
* provides a pointer to this struct using the if_index.
* bdg_softc has a backpointer to the struct ifnet, the bridge
* flags, and a cluster (bridging occurs only between port of the
* same cluster).
*/
struct bdg_softc {
struct ifnet *ifp ;
/* ((struct arpcom *)ifp)->ac_enaddr is the eth. addr */
int flags ;
#define IFF_BDG_PROMISC 0x0001 /* set promisc mode on this if. */
#define IFF_MUTE 0x0002 /* mute this if for bridging. */
#define IFF_USED 0x0004 /* use this if for bridging. */
short cluster_id ; /* in network format */
u_long magic;
} ;
static struct bdg_stats bdg_stats ;
static struct bdg_softc *ifp2sc = NULL ;
/* XXX make it static of size BDG_MAX_PORTS */
#define USED(ifp) (ifp2sc[ifp->if_index].flags & IFF_USED)
#define MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
#define MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
#define UNMUTE(ifp) ifp2sc[ifp->if_index].flags &= ~IFF_MUTE
#define CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster_id)
#define IFP_CHK(ifp, x) \
if (ifp2sc[ifp->if_index].magic != 0xDEADBEEF) { x ; }
#define SAMECLUSTER(ifp,src) \
(src == NULL || CLUSTER(ifp) == CLUSTER(src) )
/*
* turn off promisc mode, optionally clear the IFF_USED flag
*/
static void
bdg_promisc_off(int clear_used)
{
struct ifnet *ifp ;
for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next ) {
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) ;
if (clear_used)
ifp2sc[ifp->if_index].flags &= ~(IFF_USED) ;
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);
}
}
}
/*
* set promisc mode on the interfaces we use.
*/
static void
bdg_promisc_on()
{
struct ifnet *ifp ;
int s ;
for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next ) {
if ( !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 (MUTED(ifp)) {
printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);
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 (bdg_table == NULL)
do_bridge = 0 ;
if (oldval != do_bridge) {
flush_table();
if (do_bridge == 0)
bdg_promisc_off( 0 ); /* leave IFF_USED set */
else
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.
*/
static void
parse_bdg_cfg()
{
char *p, *beg ;
int i, l, cluster;
struct bdg_softc *b;
for (p= bridge_cfg; *p ; p++) {
/* interface names begin with [a-z] and continue up to ':' */
if (*p < 'a' || *p > 'z')
continue ;
for ( beg = p ; *p && *p != ':' ; p++ )
;
if (*p == 0) /* end of string, ':' not found */
return ;
l = p - beg ; /* length of name string */
p++ ;
DDB(printf("-- match beg(%d) <%s> p <%s>\n", l, beg, p);)
for (cluster = 0 ; *p && *p >= '0' && *p <= '9' ; p++)
cluster = cluster*10 + (*p -'0');
/*
* 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)) { /* XXX not correct for >10 if! */
b->cluster_id = htons(cluster) ;
b->flags |= IFF_USED ;
sprintf(bdg_stats.s[ifp->if_index].name+l,
":%d", cluster);
DDB(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");
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 */
int bdg_in_count = 0 , bdg_in_ticks = 0 , bdg_fw_count = 0, bdg_fw_ticks = 0 ;
SYSCTL_INT(_net_link_ether, OID_AUTO, bdginc, CTLFLAG_RW, &bdg_in_count,0,"");
SYSCTL_INT(_net_link_ether, OID_AUTO, bdgint, CTLFLAG_RW, &bdg_in_ticks,0,"");
SYSCTL_INT(_net_link_ether, OID_AUTO, bdgfwc, CTLFLAG_RW, &bdg_fw_count,0,"");
SYSCTL_INT(_net_link_ether, OID_AUTO, bdgfwt, CTLFLAG_RW, &bdg_fw_ticks,0,"");
#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;
if (bdg_table == NULL)
return ;
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 ;
}
}
timeout(bdg_timeout, (void *)0, 2*hz );
}
/*
* local MAC addresses are held in a small array. This makes comparisons
* much faster.
*/
unsigned char bdg_addresses[6*BDG_MAX_PORTS];
int bdg_ports ;
/*
* initialization of bridge code. This needs to be done after all
* interfaces have been configured.
*/
static void
bdginit(void *dummy)
{
if (bdg_table == NULL)
bdg_table = (struct hash_table *)
malloc(HASH_SIZE * sizeof(struct hash_table),
M_IFADDR, M_WAITOK);
flush_table();
ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
M_IFADDR, M_WAITOK );
bzero(ifp2sc, BDG_MAX_PORTS * sizeof(struct bdg_softc) );
bzero(&bdg_stats, sizeof(bdg_stats) );
bdgtakeifaces();
bdg_timeout(0);
do_bridge=0;
}
void
bdgtakeifaces(void)
{
int i ;
struct ifnet *ifp;
struct arpcom *ac ;
u_char *eth_addr ;
struct bdg_softc *bp;
bdg_ports = 0 ;
eth_addr = bdg_addresses ;
*bridge_cfg = '\0';
printf("BRIDGE 990810, have %d interfaces\n", if_index);
for (i = 0 , ifp = ifnet.tqh_first ; i < if_index ;
i++, ifp = ifp->if_link.tqe_next)
if (ifp->if_type == IFT_ETHER) { /* ethernet ? */
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, eth_addr, 6);
eth_addr += 6 ;
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.
*
* 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.
*/
struct ifnet *
bridge_in(struct ifnet *ifp, struct ether_header *eh)
{
int index;
struct ifnet *dst , *old ;
int dropit = 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,
MUTED(old) ? "muted":"active");
dropit = 1 ;
if ( !MUTED(old) ) {
if (++bdg_loops > 10)
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);
/* Return values:
* BDG_BCAST, BDG_MCAST, BDG_LOCAL, BDG_UNKNOWN, BDG_DROP, ifp.
* For muted interfaces, the first 3 are changed in BDG_LOCAL,
* and others to BDG_DROP. Also, for incoming packets, ifp is changed
* to BDG_DROP in case ifp == src . These mods are not necessary
* for outgoing packets from ether_output().
*/
BDG_STAT(ifp, BDG_IN);
switch ((int)dst) {
case (int)BDG_BCAST:
case (int)BDG_MCAST:
case (int)BDG_LOCAL:
case (int)BDG_UNKNOWN:
case (int)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)
return BDG_LOCAL ;
else
return BDG_DROP ;
} else {
return (dst == ifp ? BDG_DROP : dst ) ;
}
}
/*
* Forward to dst, excluding src port and muted interfaces.
* The packet is freed if possible (i.e. surely not of interest for
* the upper layer), otherwise a copy is left for use by the caller
* (pointer in *m0).
*
* It would be more efficient to make bdg_forward() always consume
* the packet, leaving to the caller the task to check if it needs a copy
* and get one in case. As it is now, bdg_forward() can sometimes make
* a copy whereas it is not necessary.
*
* INPUT:
* *m0 -- ptr to pkt (not null at call time)
* *dst -- destination (special value or ifnet *)
* (*m0)->m_pkthdr.rcvif -- NULL only for output pkts.
* OUTPUT:
* *m0 -- pointer to the packet (NULL if still existent)
*/
int
bdg_forward(struct mbuf **m0, struct ether_header *const eh, struct ifnet *dst)
{
struct ifnet *src = (*m0)->m_pkthdr.rcvif; /* could be NULL in output */
struct ifnet *ifp, *last = NULL ;
int error=0, s ;
int canfree = 0 ; /* can free the buf at the end if set */
int once = 0; /* loop only once */
struct mbuf *m ;
if (dst == BDG_DROP) { /* this should not happen */
printf("xx bdg_forward for BDG_DROP\n");
m_freem(*m0) ;
*m0 = NULL ;
return 0;
}
if (dst == BDG_LOCAL) { /* this should not happen as well */
printf("xx ouch, bdg_forward for local pkt\n");
return 0;
}
if (dst == BDG_BCAST || dst == BDG_MCAST || dst == BDG_UNKNOWN) {
ifp = ifnet.tqh_first ; /* scan all ports */
once = 0 ;
if (dst != BDG_UNKNOWN) /* need a copy for the local stack */
canfree = 0 ;
} else {
ifp = dst ;
once = 1 ;
}
if ( (u_int)(ifp) <= (u_int)BDG_FORWARD )
panic("bdg_forward: bad dst");
#ifdef IPFIREWALL
/*
* do filtering in a very similar way to what is done
* in ip_output. Only for IP packets, and only pass/fail/dummynet
* is supported. The tricky thing is to make sure that enough of
* the packet (basically, Eth+IP+TCP/UDP headers) is contiguous
* so that calls to m_pullup in ip_fw_chk will not kill the
* ethernet header.
*/
if (ip_fw_chk_ptr) {
struct ip_fw_chain *rule = NULL ;
int off;
struct ip *ip ;
m = *m0 ;
#ifdef DUMMYNET
if (m->m_type == MT_DUMMYNET) {
/*
* the packet was already tagged, so part of the
* processing was already done, and we need to go down.
*/
rule = (struct ip_fw_chain *)(m->m_data) ;
(*m0) = m = m->m_next ;
src = m->m_pkthdr.rcvif; /* could be NULL in output */
canfree = 1 ; /* for sure, a copy is not needed later. */
goto forward; /* HACK! I should obey the fw_one_pass */
}
#endif
if (bdg_ipfw == 0) /* this test must be here. */
goto forward ;
if (src == NULL)
goto forward ; /* do not apply to packets from ether_output */
if (ntohs(eh->ether_type) != ETHERTYPE_IP)
goto forward ; /* not an IP packet, ipfw is not appropriate */
/*
* In this section, canfree=1 means m is the same as *m0.
* canfree==0 means m is a copy. We need to make a copy here
* (to be destroyed on exit from the firewall section) because
* the firewall itself might destroy the packet.
* (This is not very smart... i should really change ipfw to
* leave the pkt alive!)
*/
if (canfree == 0 ) {
/*
* Need to make a copy (and for good measure, make sure that
* the header is contiguous). The original is still in *m0
*/
int needed = min(MHLEN, max_protohdr) ;
needed = min(needed, (*m0)->m_len ) ;
m = m_copypacket( (*m0), M_DONTWAIT);
if (m == NULL) {
printf("-- bdg: m_copypacket failed.\n") ;
return ENOBUFS ;
}
if (m->m_len < needed && (m = m_pullup(m, needed)) == NULL) {
printf("-- bdg: pullup failed.\n") ;
return ENOBUFS ;
}
}
/*
* 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(m, struct ip *);
NTOHS(ip->ip_len);
NTOHS(ip->ip_id);
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.
*/
off = (*ip_fw_chk_ptr)(&ip, 0, NULL, NULL, &m, &rule, NULL);
if (m == NULL) { /* pkt discarded by firewall */
/*
* At this point, if canfree==1, m and *m0 were the same
* thing, so just clear ptr. Otherwise, leave it alone, the
* upper layer might still make use of it somewhere.
*/
if (canfree)
*m0 = NULL ;
return 0 ;
}
/*
* If we get here, the firewall has passed the pkt, but the
* mbuf pointer might have changed. Restore the fields NTOHS()'d.
* Then, if canfree==1, also restore *m0.
*/
HTONS(ip->ip_len);
HTONS(ip->ip_id);
HTONS(ip->ip_off);
if (canfree) /* m was a reference to *m0, so update *m0 */
*m0 = m ;
if (off == 0) { /* a PASS rule. */
if (canfree == 0) /* destroy the copy */
m_freem(m);
goto forward ;
}
#ifdef DUMMYNET
if (off & 0x10000) {
/*
* pass the pkt to dummynet. Need to include m, dst, rule.
* Dummynet consumes the packet in all cases.
*/
dummynet_io((off & 0xffff), DN_TO_BDG_FWD, m, dst, NULL, 0, rule, 0);
if (canfree) /* dummynet has consumed the original one */
*m0 = NULL ;
return 0 ;
}
#endif
/*
* XXX add divert/forward actions...
*/
/* if none of the above matches, we have to drop the pkt */
bdg_ipfw_drops++ ;
m_freem(m);
if (canfree == 0) /* m was a copy */
m_freem(*m0);
*m0 = NULL ;
return 0 ;
}
forward:
#endif /* IPFIREWALL */
/*
* Now *m0 is the only pkt left. If canfree != 0 the pkt might be
* used by the upper layers which could scramble header fields.
* (basically ntoh*() etc.). To avoid problems, make sure that
* all fields that might be changed by the local network stack are not
* in a cluster by calling m_pullup on *m0. We lose some efficiency
* but better than having packets corrupt!
*/
if (canfree == 0 ) {
int needed = min(MHLEN, max_protohdr) ;
needed = min(needed, (*m0)->m_len ) ;
if ((*m0)->m_len < needed && (*m0 = m_pullup(*m0, needed)) == NULL) {
printf("-- bdg: pullup failed.\n") ;
return ENOBUFS ;
}
}
for (;;) {
if (last) { /* need to forward packet */
if (canfree && once ) { /* no need to copy */
m = *m0 ;
*m0 = NULL ; /* original is gone */
} else /* on a P5-90, m_copypacket takes 540 ticks */
m = m_copypacket(*m0, M_DONTWAIT);
if (m == NULL) {
printf("bdg_forward: sorry, m_copy failed!\n");
return ENOBUFS ; /* the original is still there... */
}
/*
* Last part of ether_output: add header, queue pkt and start
* output if interface not yet active.
*/
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
if (m == NULL)
return ENOBUFS;
bcopy(eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
s = splimp();
if (IF_QFULL(&last->if_snd)) {
IF_DROP(&last->if_snd);
#if 0
MUTE(last); /* should I also mute ? */
#endif
splx(s);
m_freem(m); /* consume the pkt anyways */
error = ENOBUFS ;
} else {
last->if_obytes += m->m_pkthdr.len ;
if (m->m_flags & M_MCAST)
last->if_omcasts++;
IF_ENQUEUE(&last->if_snd, m);
if ((last->if_flags & IFF_OACTIVE) == 0)
(*last->if_start)(last);
splx(s);
}
BDG_STAT(last, BDG_OUT);
last = NULL ;
if (once)
break ;
}
if (ifp == NULL)
break ;
if (ifp != src && /* do not send to self */
USED(ifp) && /* if used for bridging */
! IF_QFULL(&ifp->if_snd) &&
(ifp->if_flags & (IFF_UP|IFF_RUNNING)) ==
(IFF_UP|IFF_RUNNING) &&
SAMECLUSTER(ifp, src) && !MUTED(ifp) )
last = ifp ;
ifp = ifp->if_link.tqe_next ;
if (ifp == NULL)
once = 1 ;
}
return error ;
}
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