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         netif_receive_skb(skb);
  27         return 0;
  28 }
  29
  30 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
  31 {
  32         struct net_device *indev;
  33
  34         br->statistics.rx_packets++;
  35         br->statistics.rx_bytes += skb->len;
  36
  37         indev = skb->dev;
  38         skb->dev = br->dev;
  39
  40         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
  41                         br_pass_frame_up_finish);
  42 }
  43
  44 /* note: already called with rcu_read_lock (preempt_disabled) */
  45 int br_handle_frame_finish(struct sk_buff *skb)
  46 {
  47         const unsigned char *dest = eth_hdr(skb)->h_dest;
  48         struct net_bridge_port *p = skb->dev->br_port;
  49         struct net_bridge *br = p->br;
  50         struct net_bridge_fdb_entry *dst;
  51         int passedup = 0;
  52
  53         /* insert into forwarding database after filtering to avoid spoofing */
  54         br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
  55
  56         if (p->state == BR_STATE_LEARNING) {
  57                 kfree_skb(skb);
  58                 goto out;
  59         }
  60
  61         if (br->dev->flags & IFF_PROMISC) {
  62                 struct sk_buff *skb2;
  63
  64                 skb2 = skb_clone(skb, GFP_ATOMIC);
  65                 if (skb2 != NULL) {
  66                         passedup = 1;
  67                         br_pass_frame_up(br, skb2);
  68                 }
  69         }
  70
  71         if (is_multicast_ether_addr(dest)) {
  72                 br_flood_forward(br, skb, !passedup);
  73                 if (!passedup)
  74                         br_pass_frame_up(br, skb);
  75                 goto out;
  76         }
  77
  78         dst = __br_fdb_get(br, dest);
  79         if (dst != NULL && dst->is_local) {
  80                 if (!passedup)
  81                         br_pass_frame_up(br, skb);
  82                 else
  83                         kfree_skb(skb);
  84                 goto out;
  85         }
  86
  87         if (dst != NULL) {
  88                 br_forward(dst->dst, skb);
  89                 goto out;
  90         }
  91
  92         br_flood_forward(br, skb, 0);
  93
  94 out:
  95         return 0;
  96 }
  97
  98 /*
  99  * Called via br_handle_frame_hook.
 100  * Return 0 if *pskb should be processed furthur
 101  *        1 if *pskb is handled
 102  * note: already called with rcu_read_lock (preempt_disabled)
 103  */
 104 int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
 105 {
 106         struct sk_buff *skb = *pskb;
 107         const unsigned char *dest = eth_hdr(skb)->h_dest;
 108
 109         if (p->state == BR_STATE_DISABLED)
 110                 goto err;
 111
 112         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
 113                 goto err;
 114
 115         if (p->br->stp_enabled &&
 116             !memcmp(dest, bridge_ula, 5) &&
 117             !(dest[5] & 0xF0)) {
 118                 if (!dest[5]) {
 119                         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 120                                 NULL, br_stp_handle_bpdu);
 121                         return 1;
 122                 }
 123                 goto err;
 124         }
 125
 126         if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {
 127                 if (br_should_route_hook) {
 128                         if (br_should_route_hook(pskb))
 129                                 return 0;
 130                         skb = *pskb;
 131                         dest = eth_hdr(skb)->h_dest;
 132                 }
 133
 134                 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
 135                         skb->pkt_type = PACKET_HOST;
 136
 137                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 138                         br_handle_frame_finish);
 139                 return 1;
 140         }
 141
 142 err:
 143         kfree_skb(skb);
 144         return 1;
 145 }