1151 lines
32 KiB
C
1151 lines
32 KiB
C
/*
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* Copyright (c) 1998-2002 Luigi Rizzo
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*
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* Work partly supported by: Cisco Systems, Inc. - NSITE lab, RTP, NC
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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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* interfaces, including VLANs (others are still usable for routing).
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* A FreeBSD host can implement multiple logical bridges, called
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* "clusters". Each cluster is made of a set of interfaces, and
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* identified by a "cluster-id" which is a number in the range 1..2^16-1.
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*
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* Bridging is enabled by the sysctl variable
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* net.link.ether.bridge
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* the grouping of interfaces into clusters is done with
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* net.link.ether.bridge_cfg
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* containing a list of interfaces each optionally followed by
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* a colon and the cluster it belongs to (1 is the default).
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* Separators can be * spaces, commas or tabs, e.g.
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* net.link.ether.bridge_cfg="fxp0:2 fxp1:2 dc0 dc1:1"
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* Optionally bridged packets can be passed through the firewall,
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* this is controlled by the variable
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* net.link.ether.bridge_ipfw
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*
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* For each cluster there is a descriptor (cluster_softc) storing
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* the following data structures:
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* - a hash table with the MAC address and destination interface for each
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* known node. The table is indexed using a hash of the source address.
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* - an array with the MAC addresses of the interfaces used in the cluster.
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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 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 by bridge_dst_lookup(),
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* and then forwarding is done by bdg_forward().
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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.
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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 per cluster is supposed to have addresses set (but
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* there are no substantial problems if you set addresses for none or
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* for more 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 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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* - be very careful when bridging VLANs
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* - loop detection is still not very robust.
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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/protosw.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/ctype.h> /* string functions */
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <net/pfil.h> /* for ipfilter */
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/if_var.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 <net/route.h>
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#include <netinet/ip_fw.h>
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#include <netinet/ip_dummynet.h>
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#include <net/bridge.h>
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/*--------------------*/
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/*
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* For each cluster, source MAC addresses are stored into a hash
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* table which locates the port they reside on.
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*/
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#define HASH_SIZE 8192 /* Table size, must be a power of 2 */
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typedef struct hash_table { /* each entry. */
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struct ifnet * name;
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u_char etheraddr[6];
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u_int16_t used; /* also, padding */
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} bdg_hash_table ;
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/*
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* The hash function applied to MAC addresses. Out of the 6 bytes,
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* the last ones tend to vary more. Since we are on a little endian machine,
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* we have to do some gimmick...
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*/
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#define HASH_FN(addr) ( \
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ntohs( ((u_int16_t *)addr)[1] ^ ((u_int16_t *)addr)[2] ) & (HASH_SIZE -1))
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/*
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* This is the data structure where local addresses are stored.
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*/
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struct bdg_addr {
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u_char etheraddr[6] ;
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u_int16_t _padding ;
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};
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/*
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* The configuration of each cluster includes the cluster id, a pointer to
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* the hash table, and an array of local MAC addresses (of size "ports").
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*/
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struct cluster_softc {
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u_int16_t cluster_id;
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u_int16_t ports;
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bdg_hash_table *ht;
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struct bdg_addr *my_macs; /* local MAC addresses */
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};
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extern struct protosw inetsw[]; /* from netinet/ip_input.c */
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extern u_char ip_protox[]; /* from netinet/ip_input.c */
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static int n_clusters; /* number of clusters */
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static struct cluster_softc *clusters;
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#define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
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#define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
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#define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster)
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#define BDG_SAMECLUSTER(ifp,src) \
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(src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) )
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#ifdef __i386__
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#define BDG_MATCH(a,b) ( \
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((u_int16_t *)(a))[2] == ((u_int16_t *)(b))[2] && \
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*((u_int32_t *)(a)) == *((u_int32_t *)(b)) )
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#define IS_ETHER_BROADCAST(a) ( \
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*((u_int32_t *)(a)) == 0xffffffff && \
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((u_int16_t *)(a))[2] == 0xffff )
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#else
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/* for machines that do not support unaligned access */
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#define BDG_MATCH(a,b) (!bcmp(a, b, ETHER_ADDR_LEN) )
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#define IS_ETHER_BROADCAST(a) (!bcmp(a, "\377\377\377\377\377\377", 6))
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#endif
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/*
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* For timing-related 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 int bdginit(void);
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static void parse_bdg_cfg(void);
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static int bdg_ipf; /* IPFilter enabled in bridge */
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static int bdg_ipfw;
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#if 0 /* debugging only */
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static char *bdg_dst_names[] = {
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"BDG_NULL ",
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"BDG_BCAST ",
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"BDG_MCAST ",
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"BDG_LOCAL ",
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"BDG_DROP ",
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"BDG_UNKNOWN ",
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"BDG_IN ",
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"BDG_OUT ",
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"BDG_FORWARD " };
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#endif
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/*
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* System initialization
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*/
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static struct bdg_stats bdg_stats ;
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static struct callout_handle bdg_timeout_h ;
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/*
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* Add an interface to a cluster, possibly creating a new entry in
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* the cluster table. This requires reallocation of the table and
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* updating pointers in ifp2sc.
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*/
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static struct cluster_softc *
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add_cluster(u_int16_t cluster_id, struct arpcom *ac)
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{
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struct cluster_softc *c = NULL;
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int i;
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for (i = 0; i < n_clusters ; i++)
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if (clusters[i].cluster_id == cluster_id)
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goto found;
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/* Not found, need to reallocate */
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c = malloc((1+n_clusters) * sizeof (*c), M_IFADDR, M_DONTWAIT | M_ZERO);
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if (c == NULL) {/* malloc failure */
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printf("-- bridge: cannot add new cluster\n");
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return NULL;
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}
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c[n_clusters].ht = (struct hash_table *)
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malloc(HASH_SIZE * sizeof(struct hash_table),
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M_IFADDR, M_WAITOK | M_ZERO);
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if (c[n_clusters].ht == NULL) {
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printf("-- bridge: cannot allocate hash table for new cluster\n");
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free(c, M_IFADDR);
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return NULL;
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}
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c[n_clusters].my_macs = (struct bdg_addr *)
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malloc(BDG_MAX_PORTS * sizeof(struct bdg_addr),
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M_IFADDR, M_WAITOK | M_ZERO);
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if (c[n_clusters].my_macs == NULL) {
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printf("-- bridge: cannot allocate mac addr table for new cluster\n");
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free(c[n_clusters].ht, M_IFADDR);
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free(c, M_IFADDR);
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return NULL;
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}
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c[n_clusters].cluster_id = cluster_id;
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c[n_clusters].ports = 0;
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/*
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* now copy old descriptors here
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*/
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if (n_clusters > 0) {
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for (i=0; i < n_clusters; i++)
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c[i] = clusters[i];
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/*
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* and finally update pointers in ifp2sc
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*/
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for (i = 0 ; i < if_index && i < BDG_MAX_PORTS; i++)
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if (ifp2sc[i].cluster != NULL)
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ifp2sc[i].cluster = c + (ifp2sc[i].cluster - clusters);
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free(clusters, M_IFADDR);
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}
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clusters = c;
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i = n_clusters; /* index of cluster entry */
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n_clusters++;
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found:
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c = clusters + i; /* the right cluster ... */
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bcopy(ac->ac_enaddr, &(c->my_macs[c->ports]), 6);
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c->ports++;
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return c;
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}
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/*
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* Turn off bridging, by clearing promisc mode on the interface,
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* marking the interface as unused, and clearing the name in the
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* stats entry.
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* Also dispose the hash tables associated with the clusters.
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*/
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static void
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bridge_off(void)
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{
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struct ifnet *ifp ;
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int i, s;
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DEB(printf("bridge_off: n_clusters %d\n", n_clusters);)
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TAILQ_FOREACH(ifp, &ifnet, if_link) {
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struct bdg_softc *b;
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if (ifp->if_index >= BDG_MAX_PORTS)
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continue; /* make sure we do not go beyond the end */
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b = &(ifp2sc[ifp->if_index]);
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if ( b->flags & IFF_BDG_PROMISC ) {
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s = splimp();
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ifpromisc(ifp, 0);
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splx(s);
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b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
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DEB(printf(">> now %s%d promisc OFF 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, b->flags);)
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}
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b->flags &= ~(IFF_USED) ;
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b->cluster = NULL;
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bdg_stats.s[ifp->if_index].name[0] = '\0';
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}
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/* flush_tables */
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s = splimp();
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for (i=0; i < n_clusters; i++) {
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free(clusters[i].ht, M_IFADDR);
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free(clusters[i].my_macs, M_IFADDR);
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}
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if (clusters != NULL)
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free(clusters, M_IFADDR);
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clusters = NULL;
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n_clusters =0;
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splx(s);
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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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bridge_on(void)
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{
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struct ifnet *ifp ;
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int s ;
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TAILQ_FOREACH(ifp, &ifnet, if_link) {
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struct bdg_softc *b = &ifp2sc[ifp->if_index];
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if ( !(b->flags & IFF_USED) )
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continue ;
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if ( !( 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 ( !(b->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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b->flags |= IFF_BDG_PROMISC ;
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DEB(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, b->flags);)
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}
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if (b->flags & IFF_MUTE) {
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DEB(printf(">> unmuting %s%d\n", ifp->if_name, ifp->if_unit);)
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b->flags &= ~IFF_MUTE;
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}
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}
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}
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/**
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* reconfigure bridge.
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* This is also done every time we attach or detach an interface.
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* Main use is to make sure that we do not bridge on some old
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* (ejected) device. So, it would be really useful to have a
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* pointer to the modified device as an argument. Without it, we
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* have to scan all interfaces.
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*/
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static void
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reconfigure_bridge(void)
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{
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bridge_off();
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if (do_bridge) {
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if (if_index >= BDG_MAX_PORTS) {
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printf("-- sorry too many interfaces (%d, max is %d),"
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" disabling bridging\n", if_index, BDG_MAX_PORTS);
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do_bridge=0;
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return;
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}
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parse_bdg_cfg();
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bridge_on();
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}
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}
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static char bridge_cfg[1024]; /* in BSS so initialized to all NULs */
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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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* The config string is a list of "if[:cluster]" with
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* a number of possible separators (see "sep"). In particular the
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* use of the space lets you set bridge_cfg with the output from
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* "ifconfig -l"
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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 l, cluster;
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static char *sep = ", \t";
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for (p = bridge_cfg; *p ; p++) {
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struct ifnet *ifp;
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int found = 0;
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char c;
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if (index(sep, *p)) /* skip separators */
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continue ;
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/* names are lowercase and digits */
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for ( beg = p ; islower(*p) || isdigit(*p) ; p++ )
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;
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l = p - beg ; /* length of name string */
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if (l == 0) /* invalid name */
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break ;
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if ( *p != ':' ) /* no ':', assume default cluster 1 */
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cluster = 1 ;
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else /* fetch cluster */
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cluster = strtoul( p+1, &p, 10);
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c = *p;
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*p = '\0';
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/*
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* now search in interface list for a matching name
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*/
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TAILQ_FOREACH(ifp, &ifnet, if_link) {
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char buf[IFNAMSIZ];
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snprintf(buf, sizeof(buf), "%s%d", ifp->if_name, ifp->if_unit);
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if (!strncmp(beg, buf, max(l, strlen(buf)))) {
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struct bdg_softc *b = &ifp2sc[ifp->if_index];
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if (ifp->if_type != IFT_ETHER && ifp->if_type != IFT_L2VLAN) {
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printf("%s is not an ethernet, continue\n", buf);
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continue;
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}
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if (b->flags & IFF_USED) {
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printf("%s already used, skipping\n", buf);
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break;
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}
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b->cluster = add_cluster(htons(cluster), (struct arpcom *)ifp);
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b->flags |= IFF_USED ;
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sprintf(bdg_stats.s[ifp->if_index].name,
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"%s%d:%d", ifp->if_name, ifp->if_unit, cluster);
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DEB(printf("--++ found %s next c %d\n",
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bdg_stats.s[ifp->if_index].name, c);)
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found = 1;
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break ;
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}
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}
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if (!found)
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printf("interface %s Not found in bridge\n", beg);
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*p = c;
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if (c == '\0')
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break; /* no more */
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}
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}
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|
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/*
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* handler for net.link.ether.bridge
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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, 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 (oldval != do_bridge)
|
|
reconfigure_bridge();
|
|
return error ;
|
|
}
|
|
|
|
/*
|
|
* handler for net.link.ether.bridge_cfg
|
|
*/
|
|
static int
|
|
sysctl_bdg_cfg(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error = 0 ;
|
|
char old_cfg[1024] ;
|
|
|
|
strcpy(old_cfg, 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,
|
|
old_cfg, bridge_cfg);
|
|
)
|
|
if (strcmp(old_cfg, bridge_cfg))
|
|
reconfigure_bridge();
|
|
return error ;
|
|
}
|
|
|
|
static int
|
|
sysctl_refresh(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
if (req->newptr)
|
|
reconfigure_bridge();
|
|
|
|
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");
|
|
|
|
SYSCTL_INT(_net_link_ether, OID_AUTO, bridge_ipf, CTLFLAG_RW,
|
|
&bdg_ipf, 0,"Pass bridged pkts through IPFilter");
|
|
|
|
/*
|
|
* 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_dropped, "Packets dropped 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 ;
|
|
|
|
/*
|
|
* called periodically to flush entries etc.
|
|
*/
|
|
static void
|
|
bdg_timeout(void *dummy)
|
|
{
|
|
static int slowtimer; /* in BSS so initialized to 0 */
|
|
|
|
if (do_bridge) {
|
|
static int age_index = 0 ; /* index of table position to age */
|
|
int l = age_index + HASH_SIZE/4 ;
|
|
int i;
|
|
/*
|
|
* age entries in the forwarding table.
|
|
*/
|
|
if (l > HASH_SIZE)
|
|
l = HASH_SIZE ;
|
|
|
|
for (i=0; i<n_clusters; i++) {
|
|
bdg_hash_table *bdg_table = clusters[i].ht;
|
|
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 ;
|
|
|
|
bridge_on() ; /* we just need unmute, really */
|
|
bdg_loops = 0 ;
|
|
}
|
|
}
|
|
bdg_timeout_h = timeout(bdg_timeout, NULL, 2*hz );
|
|
}
|
|
|
|
/*
|
|
* Find the right pkt destination:
|
|
* BDG_BCAST is a broadcast
|
|
* BDG_MCAST is a multicast
|
|
* BDG_LOCAL is for a local address
|
|
* BDG_DROP must be dropped
|
|
* other ifp of the dest. interface (incl.self)
|
|
*
|
|
* We assume this is only called for interfaces for which bridging
|
|
* is enabled, i.e. BDG_USED(ifp) is true.
|
|
*/
|
|
static __inline
|
|
struct ifnet *
|
|
bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c)
|
|
{
|
|
struct ifnet *dst ;
|
|
int index ;
|
|
struct bdg_addr *p ;
|
|
bdg_hash_table *bt; /* pointer to entry in hash table */
|
|
|
|
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 = c->ports, p = c->my_macs; 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 );
|
|
bt = &(c->ht[index]);
|
|
dst = bt->name;
|
|
if ( dst && BDG_MATCH( bt->etheraddr, eh->ether_dhost) )
|
|
return dst ;
|
|
else
|
|
return BDG_UNKNOWN ;
|
|
}
|
|
|
|
/**
|
|
* bridge_in() is invoked to perform bridging decision on input packets.
|
|
*
|
|
* On Input:
|
|
* eh Ethernet header of the incoming packet.
|
|
* ifp interface the packet is coming from.
|
|
*
|
|
* On Return: destination of packet, one of
|
|
* BDG_BCAST broadcast
|
|
* BDG_MCAST multicast
|
|
* BDG_LOCAL is only for a local address (do not forward)
|
|
* BDG_DROP drop the packet
|
|
* ifp ifp of the destination interface.
|
|
*
|
|
* Forwarding is not done directly to give a chance to some drivers
|
|
* to fetch more of the packet, or simply drop it completely.
|
|
*/
|
|
|
|
static struct ifnet *
|
|
bridge_in(struct ifnet *ifp, struct ether_header *eh)
|
|
{
|
|
int index;
|
|
struct ifnet *dst , *old ;
|
|
bdg_hash_table *bt; /* location in hash table */
|
|
int dropit = BDG_MUTED(ifp) ;
|
|
|
|
/*
|
|
* hash the source address
|
|
*/
|
|
index= HASH_FN(eh->ether_shost);
|
|
bt = &(ifp2sc[ifp->if_index].cluster->ht[index]);
|
|
bt->used = 1 ;
|
|
old = bt->name ;
|
|
if ( old ) { /* the entry is valid. */
|
|
if (!BDG_MATCH( eh->ether_shost, bt->etheraddr) ) {
|
|
bdg_ipfw_colls++ ;
|
|
bt->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.
|
|
*/
|
|
bt->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 (bt->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, bt->etheraddr, 6);
|
|
bt->name = ifp ;
|
|
}
|
|
dst = bridge_dst_lookup(eh, ifp2sc[ifp->if_index].cluster);
|
|
/*
|
|
* 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.
|
|
*/
|
|
static struct mbuf *
|
|
bdg_forward(struct mbuf *m0, struct ifnet *dst)
|
|
{
|
|
#define EH_RESTORE(_m) do { \
|
|
M_PREPEND((_m), ETHER_HDR_LEN, M_NOWAIT); \
|
|
if ((_m) == NULL) { \
|
|
bdg_dropped++; \
|
|
return NULL; \
|
|
} \
|
|
if (eh != mtod((_m), struct ether_header *)) \
|
|
bcopy(&save_eh, mtod((_m), struct ether_header *), ETHER_HDR_LEN); \
|
|
else \
|
|
bdg_predict++; \
|
|
} while (0);
|
|
struct ether_header *eh;
|
|
struct ifnet *src;
|
|
struct ifnet *ifp, *last;
|
|
int shared = bdg_copy ; /* someone else is using the mbuf */
|
|
int once = 0; /* loop only once */
|
|
struct ifnet *real_dst = dst ; /* real dst from ether_output */
|
|
struct ip_fw_args args;
|
|
#ifdef PFIL_HOOKS
|
|
struct packet_filter_hook *pfh;
|
|
int rv;
|
|
#endif /* PFIL_HOOKS */
|
|
struct ether_header save_eh;
|
|
|
|
DEB(quad_t ticks; ticks = rdtsc();)
|
|
|
|
args.rule = NULL; /* did we match a firewall rule ? */
|
|
/* Fetch state from dummynet tag, ignore others */
|
|
for (;m0->m_type == MT_TAG; m0 = m0->m_next)
|
|
if (m0->_m_tag_id == PACKET_TAG_DUMMYNET) {
|
|
args.rule = ((struct dn_pkt *)m0)->rule;
|
|
shared = 0; /* For sure this is our own mbuf. */
|
|
}
|
|
if (args.rule == NULL)
|
|
bdg_thru++; /* first time through bdg_forward, count packet */
|
|
|
|
/*
|
|
* The packet arrives with the Ethernet header at the front.
|
|
*/
|
|
eh = mtod(m0, struct ether_header *);
|
|
|
|
src = m0->m_pkthdr.rcvif;
|
|
if (src == NULL) /* packet from ether_output */
|
|
dst = bridge_dst_lookup(eh, ifp2sc[real_dst->if_index].cluster);
|
|
|
|
if (dst == BDG_DROP) { /* this should not happen */
|
|
printf("xx bdg_forward for BDG_DROP\n");
|
|
m_freem(m0);
|
|
bdg_dropped++;
|
|
return NULL;
|
|
}
|
|
if (dst == BDG_LOCAL) { /* this should not happen as well */
|
|
printf("xx ouch, bdg_forward for local pkt\n");
|
|
return m0;
|
|
}
|
|
if (dst == BDG_BCAST || dst == BDG_MCAST || 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 ((uintptr_t)(ifp) <= (u_int)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 (src != NULL && (
|
|
#ifdef PFIL_HOOKS
|
|
((pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh)) != NULL && bdg_ipf !=0) ||
|
|
#endif
|
|
(IPFW_LOADED && bdg_ipfw != 0))) {
|
|
|
|
int i;
|
|
|
|
if (args.rule != NULL && fw_one_pass)
|
|
goto forward; /* packet already partially processed */
|
|
/*
|
|
* i need some amt of data to be contiguous, and in case others need
|
|
* the packet (shared==1) also better be in the first mbuf.
|
|
*/
|
|
i = min(m0->m_pkthdr.len, max_protohdr) ;
|
|
if ( shared || m0->m_len < i) {
|
|
m0 = m_pullup(m0, i) ;
|
|
if (m0 == NULL) {
|
|
printf("-- bdg: pullup failed.\n") ;
|
|
bdg_dropped++;
|
|
return NULL ;
|
|
}
|
|
eh = mtod(m0, struct ether_header *);
|
|
}
|
|
|
|
/*
|
|
* Processing below expects the Ethernet header is stripped.
|
|
* Furthermore, the mbuf chain might be replaced at various
|
|
* places. To deal with this we copy the header to a temporary
|
|
* location, strip the header, and restore it as needed.
|
|
*/
|
|
bcopy(eh, &save_eh, ETHER_HDR_LEN); /* local copy for restore */
|
|
m_adj(m0, ETHER_HDR_LEN); /* temporarily strip header */
|
|
|
|
#ifdef PFIL_HOOKS
|
|
/*
|
|
* NetBSD-style generic packet filter, pfil(9), hooks.
|
|
* Enables ipf(8) in bridging.
|
|
*/
|
|
if (m0->m_pkthdr.len >= sizeof(struct ip) &&
|
|
ntohs(save_eh.ether_type) == ETHERTYPE_IP) {
|
|
/*
|
|
* before calling the firewall, swap fields the same as IP does.
|
|
* here we assume the pkt is an IP one and the header is contiguous
|
|
*/
|
|
struct ip *ip = mtod(m0, struct ip *);
|
|
|
|
ip->ip_len = ntohs(ip->ip_len);
|
|
ip->ip_off = ntohs(ip->ip_off);
|
|
|
|
for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link))
|
|
if (pfh->pfil_func) {
|
|
rv = pfh->pfil_func(ip, ip->ip_hl << 2, src, 0, &m0);
|
|
if (m0 == NULL) {
|
|
bdg_dropped++;
|
|
return NULL;
|
|
}
|
|
if (rv != 0) {
|
|
EH_RESTORE(m0); /* restore Ethernet header */
|
|
return m0;
|
|
}
|
|
ip = mtod(m0, struct ip *);
|
|
}
|
|
/*
|
|
* If we get here, the firewall has passed the pkt, but the mbuf
|
|
* pointer might have changed. Restore ip and the fields ntohs()'d.
|
|
*/
|
|
ip = mtod(m0, struct ip *);
|
|
ip->ip_len = htons(ip->ip_len);
|
|
ip->ip_off = htons(ip->ip_off);
|
|
}
|
|
#endif /* PFIL_HOOKS */
|
|
|
|
/*
|
|
* Prepare arguments and call the firewall.
|
|
*/
|
|
if (!IPFW_LOADED || bdg_ipfw == 0) {
|
|
EH_RESTORE(m0); /* restore Ethernet header */
|
|
goto forward; /* not using ipfw, accept the packet */
|
|
}
|
|
|
|
/*
|
|
* XXX The following code is very similar to the one in
|
|
* if_ethersubr.c:ether_ipfw_chk()
|
|
*/
|
|
|
|
args.m = m0; /* the packet we are looking at */
|
|
args.oif = NULL; /* this is an input packet */
|
|
args.divert_rule = 0; /* we do not support divert yet */
|
|
args.next_hop = NULL; /* we do not support forward yet */
|
|
args.eh = &save_eh; /* MAC header for bridged/MAC packets */
|
|
i = ip_fw_chk_ptr(&args);
|
|
m0 = args.m; /* in case the firewall used the mbuf */
|
|
|
|
EH_RESTORE(m0); /* restore Ethernet header */
|
|
|
|
if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */
|
|
return m0 ;
|
|
|
|
if (i == 0) /* a PASS rule. */
|
|
goto forward ;
|
|
if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) {
|
|
/*
|
|
* Pass the pkt to dummynet, which consumes it.
|
|
* If shared, make a copy and keep the original.
|
|
*/
|
|
struct mbuf *m ;
|
|
|
|
if (shared) {
|
|
m = m_copypacket(m0, M_DONTWAIT);
|
|
if (m == NULL) { /* copy failed, give up */
|
|
bdg_dropped++;
|
|
return NULL;
|
|
}
|
|
} else {
|
|
m = m0 ; /* pass the original to dummynet */
|
|
m0 = NULL ; /* and nothing back to the caller */
|
|
}
|
|
|
|
args.oif = real_dst;
|
|
ip_dn_io_ptr(m, (i & 0xffff),DN_TO_BDG_FWD, &args);
|
|
return m0 ;
|
|
}
|
|
/*
|
|
* XXX at some point, add support for divert/forward actions.
|
|
* If none of the above matches, we have to drop the packet.
|
|
*/
|
|
bdg_ipfw_drops++ ;
|
|
return m0 ;
|
|
}
|
|
forward:
|
|
/*
|
|
* Again, bring up the headers in case of shared bufs to avoid
|
|
* corruptions in the future.
|
|
*/
|
|
if ( shared ) {
|
|
int i = min(m0->m_pkthdr.len, max_protohdr) ;
|
|
|
|
m0 = m_pullup(m0, i) ;
|
|
if (m0 == NULL) {
|
|
bdg_dropped++ ;
|
|
return NULL ;
|
|
}
|
|
/* NB: eh is not used below; no need to recalculate it */
|
|
}
|
|
|
|
/*
|
|
* now real_dst is used to determine the cluster where to forward.
|
|
* For packets coming from ether_input, this is the one of the 'src'
|
|
* interface, whereas for locally generated packets (src==NULL) it
|
|
* is the cluster of the original destination interface, which
|
|
* was already saved into real_dst.
|
|
*/
|
|
if (src != NULL)
|
|
real_dst = src ;
|
|
|
|
last = NULL;
|
|
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");
|
|
bdg_dropped++ ;
|
|
return m0 ; /* the original is still there... */
|
|
}
|
|
}
|
|
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 ;
|
|
#undef EH_RESTORE
|
|
}
|
|
|
|
/*
|
|
* initialization of bridge code.
|
|
*/
|
|
static int
|
|
bdginit(void)
|
|
{
|
|
printf("BRIDGE 020214 loaded\n");
|
|
|
|
ifp2sc = malloc(BDG_MAX_PORTS * sizeof(struct bdg_softc),
|
|
M_IFADDR, M_WAITOK | M_ZERO );
|
|
if (ifp2sc == NULL)
|
|
return ENOMEM ;
|
|
|
|
bridge_in_ptr = bridge_in;
|
|
bdg_forward_ptr = bdg_forward;
|
|
bdgtakeifaces_ptr = reconfigure_bridge;
|
|
|
|
n_clusters = 0;
|
|
clusters = NULL;
|
|
do_bridge=0;
|
|
|
|
bzero(&bdg_stats, sizeof(bdg_stats) );
|
|
bdgtakeifaces_ptr();
|
|
bdg_timeout(0);
|
|
return 0 ;
|
|
}
|
|
|
|
/*
|
|
* initialization code, both for static and dynamic loading.
|
|
*/
|
|
static int
|
|
bridge_modevent(module_t mod, int type, void *unused)
|
|
{
|
|
int s;
|
|
int err = 0 ;
|
|
|
|
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);
|
|
bridge_off();
|
|
if (clusters)
|
|
free(clusters, M_IFADDR);
|
|
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);
|