err.no Git - linux-2.6/blob - net/bridge/br_input.c

   1 /*
   2  *      Handle incoming frames
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_input.c,v 1.10 2001/12/24 04:50:20 davem Exp $
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/netfilter_bridge.h>
  20 #include "br_private.h"
  21
  22 const unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
  23
  24 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
  25 {
  26         struct net_device *indev;
  27
  28         br->statistics.rx_packets++;
  29         br->statistics.rx_bytes += skb->len;
  30
  31         indev = skb->dev;
  32         skb->dev = br->dev;
  33
  34         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
  35                 netif_receive_skb);
  36 }
  37
  38 /* note: already called with rcu_read_lock (preempt_disabled) */
  39 int br_handle_frame_finish(struct sk_buff *skb)
  40 {
  41         const unsigned char *dest = eth_hdr(skb)->h_dest;
  42         struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
  43         struct net_bridge *br;
  44         struct net_bridge_fdb_entry *dst;
  45         int passedup = 0;
  46
  47         if (!p || p->state == BR_STATE_DISABLED)
  48                 goto drop;
  49
  50         /* insert into forwarding database after filtering to avoid spoofing */
  51         br = p->br;
  52         br_fdb_update(br, p, eth_hdr(skb)->h_source);
  53
  54         if (p->state == BR_STATE_LEARNING)
  55                 goto drop;
  56
  57         if (br->dev->flags & IFF_PROMISC) {
  58                 struct sk_buff *skb2;
  59
  60                 skb2 = skb_clone(skb, GFP_ATOMIC);
  61                 if (skb2 != NULL) {
  62                         passedup = 1;
  63                         br_pass_frame_up(br, skb2);
  64                 }
  65         }
  66
  67         if (is_multicast_ether_addr(dest)) {
  68                 br_flood_forward(br, skb, !passedup);
  69                 if (!passedup)
  70                         br_pass_frame_up(br, skb);
  71                 goto out;
  72         }
  73
  74         dst = __br_fdb_get(br, dest);
  75         if (dst != NULL && dst->is_local) {
  76                 if (!passedup)
  77                         br_pass_frame_up(br, skb);
  78                 else
  79                         kfree_skb(skb);
  80                 goto out;
  81         }
  82
  83         if (dst != NULL) {
  84                 br_forward(dst->dst, skb);
  85                 goto out;
  86         }
  87
  88         br_flood_forward(br, skb, 0);
  89
  90 out:
  91         return 0;
  92 drop:
  93         kfree_skb(skb);
  94         goto out;
  95 }
  96
  97 /*
  98  * Called via br_handle_frame_hook.
  99  * Return 0 if *pskb should be processed furthur
 100  *        1 if *pskb is handled
 101  * note: already called with rcu_read_lock (preempt_disabled)
 102  */
 103 int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
 104 {
 105         struct sk_buff *skb = *pskb;
 106         const unsigned char *dest = eth_hdr(skb)->h_dest;
 107
 108         if (p->state == BR_STATE_DISABLED)
 109                 goto err;
 110
 111         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
 112                 goto err;
 113
 114         if (p->br->stp_enabled &&
 115             !memcmp(dest, bridge_ula, 5) &&
 116             !(dest[5] & 0xF0)) {
 117                 if (!dest[5]) {
 118                         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 119                                 NULL, br_stp_handle_bpdu);
 120                         return 1;
 121                 }
 122                 goto err;
 123         }
 124
 125         if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {
 126                 if (br_should_route_hook) {
 127                         if (br_should_route_hook(pskb))
 128                                 return 0;
 129                         skb = *pskb;
 130                         dest = eth_hdr(skb)->h_dest;
 131                 }
 132
 133                 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
 134                         skb->pkt_type = PACKET_HOST;
 135
 136                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 137                         br_handle_frame_finish);
 138                 return 1;
 139         }
 140
 141 err:
 142         kfree_skb(skb);
 143         return 1;
 144 }