859 lines
25 KiB
C
859 lines
25 KiB
C
/*
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* Copyright (c) 1998-2000 Luigi Rizzo
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* This code implements bridging in FreeBSD. It only acts on ethernet
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* type of interfaces (others are still usable for routing).
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* A bridging table holds the source MAC address/dest. interface for each
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* known node. The table is indexed using an hash of the source address.
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*
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* Input packets are tapped near the beginning of ether_input(), and
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* analysed by calling bridge_in(). Depending on the result, the packet
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* can be forwarded to one or more output interfaces using bdg_forward(),
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* and/or sent to the upper layer (e.g. in case of multicast).
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*
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* Output packets are intercepted near the end of ether_output(),
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* the correct destination is selected calling bdg_dst_lookup(),
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* and then forwarding is done using bdg_forward().
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* Bridging is controlled by the sysctl variable net.link.ether.bridge
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*
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* The arp code is also modified to let a machine answer to requests
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* irrespective of the port the request came from.
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*
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* In case of loops in the bridging topology, the bridge detects this
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* event and temporarily mutes output bridging on one of the ports.
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* Periodically, interfaces are unmuted by bdg_timeout().
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* Muting is only implemented as a safety measure, and also as
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* a mechanism to support a user-space implementation of the spanning
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* tree algorithm. In the final release, unmuting will only occur
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* because of explicit action of the user-level daemon.
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*
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* To build a bridging kernel, use the following option
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* option BRIDGE
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* and then at runtime set the sysctl variable to enable bridging.
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*
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* Only one interface is supposed to have addresses set (but
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* there are no problems in practice if you set addresses for more
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* than one interface).
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* Bridging will act before routing, but nothing prevents a machine
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* from doing both (modulo bugs in the implementation...).
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*
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* THINGS TO REMEMBER
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* - bridging requires some (small) modifications to the interface
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* driver. Not all of them have been changed, see the "ed" and "de"
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* drivers as examples on how to operate.
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* - bridging is incompatible with multicast routing on the same
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* machine. There is not an easy fix to this.
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* - loop detection is still not very robust.
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* - the interface of bdg_forward() could be improved.
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*/
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include <sys/malloc.h>
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#include <sys/systm.h>
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#include <sys/socket.h> /* for net/if.h */
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <netinet/in.h> /* for struct arpcom */
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/if_ether.h> /* for struct arpcom */
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#include "opt_ipfw.h"
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#include "opt_ipdn.h"
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#if defined(IPFIREWALL)
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#include <net/route.h>
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#include <netinet/ip_fw.h>
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#if defined(DUMMYNET)
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#include <netinet/ip_dummynet.h>
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#endif
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#endif
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#include <net/bridge.h>
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/*
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* For debugging, you can use the following macros.
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* remember, rdtsc() only works on Pentium-class machines
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quad_t ticks;
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DDB(ticks = rdtsc();)
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... interesting code ...
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DDB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;)
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*
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*/
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#define DDB(x) x
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#define DEB(x)
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static void bdginit(void *);
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static void flush_table(void);
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static void bdg_promisc_on(void);
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static void parse_bdg_cfg(void);
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static int bdg_initialized = 0;
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static int bdg_ipfw = 0 ;
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int do_bridge = 0;
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bdg_hash_table *bdg_table = NULL ;
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/*
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* System initialization
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*/
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SYSINIT(interfaces, SI_SUB_PROTO_IF, SI_ORDER_FIRST, bdginit, NULL)
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/*
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* We need additional info for the bridge. The bdg_ifp2sc[] array
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* provides a pointer to this struct using the if_index.
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* bdg_softc has a backpointer to the struct ifnet, the bridge
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* flags, and a cluster (bridging occurs only between port of the
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* same cluster).
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*/
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struct bdg_softc {
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struct ifnet *ifp ;
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/* ((struct arpcom *)ifp)->ac_enaddr is the eth. addr */
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int flags ;
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#define IFF_BDG_PROMISC 0x0001 /* set promisc mode on this if. */
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#define IFF_MUTE 0x0002 /* mute this if for bridging. */
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#define IFF_USED 0x0004 /* use this if for bridging. */
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short cluster_id ; /* in network format */
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u_long magic;
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} ;
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static struct bdg_stats bdg_stats ;
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static struct bdg_softc *ifp2sc = NULL ;
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/* XXX make it static of size BDG_MAX_PORTS */
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#define USED(ifp) (ifp2sc[ifp->if_index].flags & IFF_USED)
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#define MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
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#define MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
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#define UNMUTE(ifp) ifp2sc[ifp->if_index].flags &= ~IFF_MUTE
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#define CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster_id)
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#define IFP_CHK(ifp, x) \
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if (ifp2sc[ifp->if_index].magic != 0xDEADBEEF) { x ; }
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#define SAMECLUSTER(ifp,src) \
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(src == NULL || CLUSTER(ifp) == CLUSTER(src) )
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/*
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* turn off promisc mode, optionally clear the IFF_USED flag
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*/
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static void
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bdg_promisc_off(int clear_used)
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{
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struct ifnet *ifp ;
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for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next ) {
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if ( (ifp2sc[ifp->if_index].flags & IFF_BDG_PROMISC) ) {
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int s, ret ;
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s = splimp();
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ret = ifpromisc(ifp, 0);
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splx(s);
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ifp2sc[ifp->if_index].flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
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if (clear_used)
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ifp2sc[ifp->if_index].flags &= ~(IFF_USED) ;
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printf(">> now %s%d promisc ON if_flags 0x%x bdg_flags 0x%x\n",
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ifp->if_name, ifp->if_unit,
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ifp->if_flags, ifp2sc[ifp->if_index].flags);
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}
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}
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}
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/*
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* set promisc mode on the interfaces we use.
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*/
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static void
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bdg_promisc_on()
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{
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struct ifnet *ifp ;
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int s ;
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for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next ) {
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if ( !USED(ifp) )
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continue ;
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if ( 0 == ( ifp->if_flags & IFF_UP) ) {
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s = splimp();
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if_up(ifp);
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splx(s);
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}
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if ( !(ifp2sc[ifp->if_index].flags & IFF_BDG_PROMISC) ) {
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int ret ;
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s = splimp();
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ret = ifpromisc(ifp, 1);
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splx(s);
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ifp2sc[ifp->if_index].flags |= IFF_BDG_PROMISC ;
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printf(">> now %s%d promisc ON if_flags 0x%x bdg_flags 0x%x\n",
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ifp->if_name, ifp->if_unit,
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ifp->if_flags, ifp2sc[ifp->if_index].flags);
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}
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if (MUTED(ifp)) {
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printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);
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UNMUTE(ifp) ;
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}
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}
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}
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static int
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sysctl_bdg(SYSCTL_HANDLER_ARGS)
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{
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int error, oldval = do_bridge ;
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error = sysctl_handle_int(oidp,
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oidp->oid_arg1, oidp->oid_arg2, req);
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DEB( printf("called sysctl for bridge name %s arg2 %d val %d->%d\n",
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oidp->oid_name, oidp->oid_arg2,
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oldval, do_bridge); )
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if (bdg_table == NULL)
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do_bridge = 0 ;
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if (oldval != do_bridge) {
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flush_table();
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if (do_bridge == 0)
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bdg_promisc_off( 0 ); /* leave IFF_USED set */
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else
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bdg_promisc_on();
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}
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return error ;
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}
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static char bridge_cfg[256] = { "" } ;
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/*
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* parse the config string, set IFF_USED, name and cluster_id
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* for all interfaces found.
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*/
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static void
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parse_bdg_cfg()
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{
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char *p, *beg ;
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int i, l, cluster;
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struct bdg_softc *b;
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for (p= bridge_cfg; *p ; p++) {
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/* interface names begin with [a-z] and continue up to ':' */
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if (*p < 'a' || *p > 'z')
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continue ;
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for ( beg = p ; *p && *p != ':' ; p++ )
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;
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if (*p == 0) /* end of string, ':' not found */
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return ;
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l = p - beg ; /* length of name string */
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p++ ;
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DDB(printf("-- match beg(%d) <%s> p <%s>\n", l, beg, p);)
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for (cluster = 0 ; *p && *p >= '0' && *p <= '9' ; p++)
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cluster = cluster*10 + (*p -'0');
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/*
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* now search in bridge strings
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*/
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for (i=0, b = ifp2sc ; i < if_index ; i++, b++) {
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char buf[32];
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struct ifnet *ifp = b->ifp ;
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if (ifp == NULL)
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continue;
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sprintf(buf, "%s%d", ifp->if_name, ifp->if_unit);
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if (!strncmp(beg, buf, l)) { /* XXX not correct for >10 if! */
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b->cluster_id = htons(cluster) ;
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b->flags |= IFF_USED ;
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sprintf(bdg_stats.s[ifp->if_index].name+l,
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":%d", cluster);
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DDB(printf("--++ found %s\n",
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bdg_stats.s[ifp->if_index].name);)
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break ;
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}
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}
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}
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}
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static int
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sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
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{
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int error = 0 ;
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char oldval[256] ;
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strcpy(oldval, bridge_cfg) ;
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error = sysctl_handle_string(oidp,
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bridge_cfg, oidp->oid_arg2, req);
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DEB(
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printf("called sysctl for bridge name %s arg2 %d err %d val %s->%s\n",
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oidp->oid_name, oidp->oid_arg2,
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error,
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oldval, bridge_cfg);
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)
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if (strcmp(oldval, bridge_cfg)) {
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bdg_promisc_off( 1 ); /* reset previously-used interfaces */
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flush_table();
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parse_bdg_cfg(); /* and set new ones... */
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if (do_bridge)
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bdg_promisc_on(); /* re-enable interfaces */
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}
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return error ;
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}
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static int
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sysctl_refresh(SYSCTL_HANDLER_ARGS)
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{
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if (req->newptr)
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bdgtakeifaces();
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return 0;
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}
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SYSCTL_DECL(_net_link_ether);
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SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_cfg, CTLTYPE_STRING|CTLFLAG_RW,
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&bridge_cfg, sizeof(bridge_cfg), &sysctl_bdg_cfg, "A",
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"Bridge configuration");
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SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge, CTLTYPE_INT|CTLFLAG_RW,
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&do_bridge, 0, &sysctl_bdg, "I", "Bridging");
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SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw, CTLFLAG_RW,
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&bdg_ipfw,0,"Pass bridged pkts through firewall");
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int bdg_ipfw_drops;
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SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_drop,
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CTLFLAG_RW, &bdg_ipfw_drops,0,"");
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int bdg_ipfw_colls;
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SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipfw_collisions,
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CTLFLAG_RW, &bdg_ipfw_colls,0,"");
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SYSCTL_PROC(_net_link_ether, OID_AUTO, bridge_refresh, CTLTYPE_INT|CTLFLAG_WR,
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NULL, 0, &sysctl_refresh, "I", "iface refresh");
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#if 1 /* diagnostic vars */
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int bdg_in_count = 0 , bdg_in_ticks = 0 , bdg_fw_count = 0, bdg_fw_ticks = 0 ;
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SYSCTL_INT(_net_link_ether, OID_AUTO, bdginc, CTLFLAG_RW, &bdg_in_count,0,"");
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SYSCTL_INT(_net_link_ether, OID_AUTO, bdgint, CTLFLAG_RW, &bdg_in_ticks,0,"");
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SYSCTL_INT(_net_link_ether, OID_AUTO, bdgfwc, CTLFLAG_RW, &bdg_fw_count,0,"");
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SYSCTL_INT(_net_link_ether, OID_AUTO, bdgfwt, CTLFLAG_RW, &bdg_fw_ticks,0,"");
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#endif
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SYSCTL_STRUCT(_net_link_ether, PF_BDG, bdgstats,
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CTLFLAG_RD, &bdg_stats , bdg_stats, "bridge statistics");
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static int bdg_loops ;
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/*
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* completely flush the bridge table.
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*/
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static void
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flush_table()
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{
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int s,i;
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if (bdg_table == NULL)
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return ;
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s = splimp();
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for (i=0; i< HASH_SIZE; i++)
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bdg_table[i].name= NULL; /* clear table */
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splx(s);
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}
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/*
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* called periodically to flush entries etc.
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*/
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static void
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bdg_timeout(void *dummy)
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{
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static int slowtimer = 0 ;
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if (do_bridge) {
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static int age_index = 0 ; /* index of table position to age */
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int l = age_index + HASH_SIZE/4 ;
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/*
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* age entries in the forwarding table.
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*/
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if (l > HASH_SIZE)
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l = HASH_SIZE ;
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for (; age_index < l ; age_index++)
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if (bdg_table[age_index].used)
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bdg_table[age_index].used = 0 ;
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else if (bdg_table[age_index].name) {
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/* printf("xx flushing stale entry %d\n", age_index); */
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bdg_table[age_index].name = NULL ;
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}
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if (age_index >= HASH_SIZE)
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age_index = 0 ;
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if (--slowtimer <= 0 ) {
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slowtimer = 5 ;
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bdg_promisc_on() ; /* we just need unmute, really */
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bdg_loops = 0 ;
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}
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}
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timeout(bdg_timeout, (void *)0, 2*hz );
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}
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/*
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* local MAC addresses are held in a small array. This makes comparisons
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* much faster.
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*/
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unsigned char bdg_addresses[6*BDG_MAX_PORTS];
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int bdg_ports ;
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/*
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* initialization of bridge code. This needs to be done after all
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* interfaces have been configured.
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*/
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static void
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bdginit(void *dummy)
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{
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bdg_initialized++;
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if (bdg_table == NULL)
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bdg_table = (struct hash_table *)
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malloc(HASH_SIZE * sizeof(struct hash_table),
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M_IFADDR, M_WAITOK);
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flush_table();
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ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
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M_IFADDR, M_WAITOK | M_ZERO);
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bzero(&bdg_stats, sizeof(bdg_stats) );
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bdgtakeifaces();
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bdg_timeout(0);
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do_bridge=0;
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}
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void
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bdgtakeifaces(void)
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{
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int i ;
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struct ifnet *ifp;
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struct arpcom *ac ;
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u_char *eth_addr ;
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struct bdg_softc *bp;
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if (!bdg_initialized)
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return;
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bdg_ports = 0 ;
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eth_addr = bdg_addresses ;
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*bridge_cfg = '\0';
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printf("BRIDGE 990810, have %d interfaces\n", if_index);
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for (i = 0 , ifp = ifnet.tqh_first ; i < if_index ;
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i++, ifp = ifp->if_link.tqe_next)
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if (ifp->if_type == IFT_ETHER) { /* ethernet ? */
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bp = &ifp2sc[ifp->if_index] ;
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ac = (struct arpcom *)ifp;
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sprintf(bridge_cfg + strlen(bridge_cfg),
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"%s%d:1,", ifp->if_name, ifp->if_unit);
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printf("-- index %d %s type %d phy %d addrl %d addr %6D\n",
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ifp->if_index,
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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");
|
|
#ifdef DUMMYNET
|
|
if ((*m0)->m_type == MT_DUMMYNET)
|
|
/* XXX: Shouldn't have to be doing this. */
|
|
m_freem((*m0)->m_next);
|
|
else
|
|
#endif
|
|
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_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_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.
|
|
* Also need to prepend the ethernet header.
|
|
*/
|
|
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
|
|
if (m == NULL) {
|
|
if (canfree)
|
|
*m0 = NULL;
|
|
return ENOBUFS;
|
|
}
|
|
bcopy(eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
|
|
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);
|
|
#ifdef DIAGNOSTIC
|
|
printf("bdg_forward: No rules match, so dropping packet!\n");
|
|
#endif
|
|
*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
|
|
m = m_dup(*m0, M_DONTWAIT); /* XXX m_copypacket should work */
|
|
if (m == NULL) {
|
|
printf("bdg_forward: sorry, m_dup 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);
|
|
if (! IF_HANDOFF(&last->if_snd, m, last)) {
|
|
#if 0
|
|
MUTE(last); /* should I also mute ? */
|
|
#endif
|
|
error = ENOBUFS ;
|
|
}
|
|
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 ;
|
|
}
|