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_receive_skb(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 /* note: already called with rcu_read_lock (preempt_disabled) */
  49 int br_handle_frame_finish(struct sk_buff *skb)
  50 {
  51         const unsigned char *dest = eth_hdr(skb)->h_dest;
  52         struct net_bridge_port *p = skb->dev->br_port;
  53         struct net_bridge *br = p->br;
  54         struct net_bridge_fdb_entry *dst;
  55         int passedup = 0;
  56
  57         /* insert into forwarding database after filtering to avoid spoofing */
  58         br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
  59
  60         if (br->dev->flags & IFF_PROMISC) {
  61                 struct sk_buff *skb2;
  62
  63                 skb2 = skb_clone(skb, GFP_ATOMIC);
  64                 if (skb2 != NULL) {
  65                         passedup = 1;
  66                         br_pass_frame_up(br, skb2);
  67                 }
  68         }
  69
  70         if (dest[0] & 1) {
  71                 br_flood_forward(br, skb, !passedup);
  72                 if (!passedup)
  73                         br_pass_frame_up(br, skb);
  74                 goto out;
  75         }
  76
  77         dst = __br_fdb_get(br, dest);
  78         if (dst != NULL && dst->is_local) {
  79                 if (!passedup)
  80                         br_pass_frame_up(br, skb);
  81                 else
  82                         kfree_skb(skb);
  83                 goto out;
  84         }
  85
  86         if (dst != NULL) {
  87                 br_forward(dst->dst, skb);
  88                 goto out;
  89         }
  90
  91         br_flood_forward(br, skb, 0);
  92
  93 out:
  94         return 0;
  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->state == BR_STATE_LEARNING)
 115                 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
 116
 117         if (p->br->stp_enabled &&
 118             !memcmp(dest, bridge_ula, 5) &&
 119             !(dest[5] & 0xF0)) {
 120                 if (!dest[5]) {
 121                         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 122                                 NULL, br_stp_handle_bpdu);
 123                         return 1;
 124                 }
 125         }
 126
 127         else if (p->state == BR_STATE_FORWARDING) {
 128                 if (br_should_route_hook) {
 129                         if (br_should_route_hook(pskb))
 130                                 return 0;
 131                         skb = *pskb;
 132                         dest = eth_hdr(skb)->h_dest;
 133                 }
 134
 135                 if (!memcmp(p->br->dev->dev_addr, dest, ETH_ALEN))
 136                         skb->pkt_type = PACKET_HOST;
 137
 138                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
 139                         br_handle_frame_finish);
 140                 return 1;
 141         }
 142
 143 err:
 144         kfree_skb(skb);
 145         return 1;
 146 }