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 = rcu_dereference(skb->dev->br_port);
  60
  61         if (p == NULL || p->state == BR_STATE_DISABLED) {
  62                 kfree_skb(skb);
  63                 goto out;
  64         }
  65
  66         br = p->br;
  67         passedup = 0;
  68         if (br->dev->flags & IFF_PROMISC) {
  69                 struct sk_buff *skb2;
  70
  71                 skb2 = skb_clone(skb, GFP_ATOMIC);
  72                 if (skb2 != NULL) {
  73                         passedup = 1;
  74                         br_pass_frame_up(br, skb2);
  75                 }
  76         }
  77
  78         if (dest[0] & 1) {
  79                 br_flood_forward(br, skb, !passedup);
  80                 if (!passedup)
  81                         br_pass_frame_up(br, skb);
  82                 goto out;
  83         }
  84
  85         dst = __br_fdb_get(br, dest);
  86         if (dst != NULL && dst->is_local) {
  87                 if (!passedup)
  88                         br_pass_frame_up(br, skb);
  89                 else
  90                         kfree_skb(skb);
  91                 goto out;
  92         }
  93
  94         if (dst != NULL) {
  95                 br_forward(dst->dst, skb);
  96                 goto out;
  97         }
  98
  99         br_flood_forward(br, skb, 0);
 100
 101 out:
 102         rcu_read_unlock();
 103         return 0;
 104 }
 105
 106 int br_handle_frame(struct sk_buff *skb)
 107 {
 108         unsigned char *dest;
 109         struct net_bridge_port *p;
 110
 111         dest = skb->mac.ethernet->h_dest;
 112
 113         rcu_read_lock();
 114         p = skb->dev->br_port;
 115         if (p == NULL || p->state == BR_STATE_DISABLED)
 116                 goto err;
 117
 118         if (skb->mac.ethernet->h_source[0] & 1)
 119                 goto err;
 120
 121         if (p->state == BR_STATE_LEARNING ||
 122             p->state == BR_STATE_FORWARDING)
 123                 br_fdb_insert(p->br, p, skb->mac.ethernet->h_source, 0);
 124
 125         if (p->br->stp_enabled &&
 126             !memcmp(dest, bridge_ula, 5) &&
 127             !(dest[5] & 0xF0)) {
 128                 if (!dest[5]) {
 129                         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 130                                 NULL, br_stp_handle_bpdu);
 131                         rcu_read_unlock();
 132                         return 0;
 133                 }
 134         }
 135
 136         else if (p->state == BR_STATE_FORWARDING) {
 137                 if (br_should_route_hook && br_should_route_hook(&skb)) {
 138                         rcu_read_unlock();
 139                         return -1;
 140                 }
 141
 142                 if (!memcmp(p->br->dev->dev_addr, dest, ETH_ALEN))
 143                         skb->pkt_type = PACKET_HOST;
 144
 145                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 146                         br_handle_frame_finish);
 147                 rcu_read_unlock();
 148                 return 0;
 149         }
 150
 151 err:
 152         rcu_read_unlock();
 153         kfree_skb(skb);
 154         return 0;
 155 }