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 int br_pass_frame_up_finish(struct sk_buff *skb)
  25 {
  26 #ifdef CONFIG_NETFILTER_DEBUG
  27         skb->nf_debug = 0;
  28 #endif
  29         netif_rx(skb);
  30
  31         return 0;
  32 }
  33
  34 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
  35 {
  36         struct net_device *indev;
  37
  38         br->statistics.rx_packets++;
  39         br->statistics.rx_bytes += skb->len;
  40
  41         indev = skb->dev;
  42         skb->dev = br->dev;
  43
  44         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
  45                         br_pass_frame_up_finish);
  46 }
  47
  48 int br_handle_frame_finish(struct sk_buff *skb)
  49 {
  50         struct net_bridge *br;
  51         unsigned char *dest;
  52         struct net_bridge_fdb_entry *dst;
  53         struct net_bridge_port *p;
  54         int passedup;
  55
  56         dest = skb->mac.ethernet->h_dest;
  57
  58         rcu_read_lock();
  59         p = skb->dev->br_port;
  60         smp_read_barrier_depends();
  61
  62         if (p == NULL || p->state == BR_STATE_DISABLED) {
  63                 kfree_skb(skb);
  64                 goto out;
  65         }
  66
  67         br = p->br;
  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         rcu_read_unlock();
 106         return 0;
 107 }
 108
 109 int br_handle_frame(struct sk_buff *skb)
 110 {
 111         unsigned char *dest;
 112         struct net_bridge_port *p;
 113
 114         dest = skb->mac.ethernet->h_dest;
 115
 116         rcu_read_lock();
 117         p = skb->dev->br_port;
 118         if (p == NULL || p->state == BR_STATE_DISABLED)
 119                 goto err;
 120
 121         if (skb->mac.ethernet->h_source[0] & 1)
 122                 goto err;
 123
 124         if (p->state == BR_STATE_LEARNING ||
 125             p->state == BR_STATE_FORWARDING)
 126                 br_fdb_insert(p->br, p, skb->mac.ethernet->h_source, 0);
 127
 128         if (p->br->stp_enabled &&
 129             !memcmp(dest, bridge_ula, 5) &&
 130             !(dest[5] & 0xF0)) {
 131                 if (!dest[5]) {
 132                         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 133                                 NULL, br_stp_handle_bpdu);
 134                         rcu_read_unlock();
 135                         return 0;
 136                 }
 137         }
 138
 139         else if (p->state == BR_STATE_FORWARDING) {
 140                 if (br_should_route_hook && br_should_route_hook(&skb)) {
 141                         rcu_read_unlock();
 142                         return -1;
 143                 }
 144
 145                 if (!memcmp(p->br->dev->dev_addr, dest, ETH_ALEN))
 146                         skb->pkt_type = PACKET_HOST;
 147
 148                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 149                         br_handle_frame_finish);
 150                 rcu_read_unlock();
 151                 return 0;
 152         }
 153
 154 err:
 155         rcu_read_unlock();
 156         kfree_skb(skb);
 157         return 0;
 158 }