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 1.9.2.1 2001/12/24 04:50:05 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/if_bridge.h>
  20 #include <linux/netfilter_bridge.h>
  21 #include "br_private.h"
  22
  23 unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
  24
  25 static int br_pass_frame_up_finish(struct sk_buff *skb)
  26 {
  27         netif_rx(skb);
  28
  29         return 0;
  30 }
  31
  32 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
  33 {
  34         struct net_device *indev;
  35
  36         br->statistics.rx_packets++;
  37         br->statistics.rx_bytes += skb->len;
  38
  39         indev = skb->dev;
  40         skb->dev = &br->dev;
  41         skb->pkt_type = PACKET_HOST;
  42         skb_push(skb, ETH_HLEN);
  43         skb->protocol = eth_type_trans(skb, &br->dev);
  44
  45         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
  46                         br_pass_frame_up_finish);
  47 }
  48
  49 static int br_handle_frame_finish(struct sk_buff *skb)
  50 {
  51         struct net_bridge *br;
  52         unsigned char *dest;
  53         struct net_bridge_fdb_entry *dst;
  54         struct net_bridge_port *p;
  55         int passedup;
  56
  57         dest = skb->mac.ethernet->h_dest;
  58
  59         p = skb->dev->br_port;
  60         if (p == NULL)
  61                 goto err_nolock;
  62
  63         br = p->br;
  64         read_lock(&br->lock);
  65         if (skb->dev->br_port == NULL)
  66                 goto err;
  67
  68         passedup = 0;
  69         if (br->dev.flags & IFF_PROMISC) {
  70                 struct sk_buff *skb2;
  71
  72                 skb2 = skb_clone(skb, GFP_ATOMIC);
  73                 if (skb2 != NULL) {
  74                         passedup = 1;
  75                         br_pass_frame_up(br, skb2);
  76                 }
  77         }
  78
  79         if (dest[0] & 1) {
  80                 br_flood_forward(br, skb, !passedup);
  81                 if (!passedup)
  82                         br_pass_frame_up(br, skb);
  83                 goto out;
  84         }
  85
  86         dst = br_fdb_get(br, dest);
  87         if (dst != NULL && dst->is_local) {
  88                 if (!passedup)
  89                         br_pass_frame_up(br, skb);
  90                 else
  91                         kfree_skb(skb);
  92                 br_fdb_put(dst);
  93                 goto out;
  94         }
  95
  96         if (dst != NULL) {
  97                 br_forward(dst->dst, skb);
  98                 br_fdb_put(dst);
  99                 goto out;
 100         }
 101
 102         br_flood_forward(br, skb, 0);
 103
 104 out:
 105         read_unlock(&br->lock);
 106         return 0;
 107
 108 err:
 109         read_unlock(&br->lock);
 110 err_nolock:
 111         kfree_skb(skb);
 112         return 0;
 113 }
 114
 115 void br_handle_frame(struct sk_buff *skb)
 116 {
 117         struct net_bridge *br;
 118         unsigned char *dest;
 119         struct net_bridge_port *p;
 120
 121         dest = skb->mac.ethernet->h_dest;
 122
 123         p = skb->dev->br_port;
 124         if (p == NULL)
 125                 goto err_nolock;
 126
 127         br = p->br;
 128         read_lock(&br->lock);
 129         if (skb->dev->br_port == NULL)
 130                 goto err;
 131
 132         if (!(br->dev.flags & IFF_UP) ||
 133             p->state == BR_STATE_DISABLED)
 134                 goto err;
 135
 136         if (skb->mac.ethernet->h_source[0] & 1)
 137                 goto err;
 138
 139         if (p->state == BR_STATE_LEARNING ||
 140             p->state == BR_STATE_FORWARDING)
 141                 br_fdb_insert(br, p, skb->mac.ethernet->h_source, 0);
 142
 143         if (br->stp_enabled &&
 144             !memcmp(dest, bridge_ula, 5) &&
 145             !(dest[5] & 0xF0))
 146                 goto handle_special_frame;
 147
 148         if (p->state == BR_STATE_FORWARDING) {
 149                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 150                         br_handle_frame_finish);
 151                 read_unlock(&br->lock);
 152                 return;
 153         }
 154
 155 err:
 156         read_unlock(&br->lock);
 157 err_nolock:
 158         kfree_skb(skb);
 159         return;
 160
 161 handle_special_frame:
 162         if (!dest[5]) {
 163                 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,NULL,
 164                         br_stp_handle_bpdu);
 165                 read_unlock(&br->lock);
 166                 return;
 167         }
 168
 169         read_unlock(&br->lock);
 170         kfree_skb(skb);
 171 }