net/bridge/br_forward.c

   1 /*
   2  *      Forwarding decision
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_forward.c,v 1.1.1.1 2005/04/11 02:51:12 jack 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/inetdevice.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/if_bridge.h>
  21 #include <linux/netfilter_bridge.h>
  22 #include "br_private.h"
  23
  24 static inline int should_deliver(struct net_bridge_port *p, struct sk_buff *skb)
  25 {
  26         if (skb->dev == p->dev ||
  27             p->state != BR_STATE_FORWARDING)
  28                 return 0;
  29
  30         return 1;
  31 }
  32
  33 static int __dev_queue_push_xmit(struct sk_buff *skb)
  34 {
  35         skb_push(skb, ETH_HLEN);
  36         dev_queue_xmit(skb);
  37
  38         return 0;
  39 }
  40
  41 static int __br_forward_finish(struct sk_buff *skb)
  42 {
  43         NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
  44                         __dev_queue_push_xmit);
  45
  46         return 0;
  47 }
  48
  49 static void __br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
  50 {
  51         skb->dev = to->dev;
  52 #ifdef CONFIG_NETFILTER_DEBUG
  53         skb->nf_debug = 0;
  54 #endif
  55         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
  56                         __br_forward_finish);
  57 }
  58
  59 static void __br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  60 {
  61         struct net_device *indev;
  62
  63         indev = skb->dev;
  64         skb->dev = to->dev;
  65
  66         NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
  67                         __br_forward_finish);
  68 }
  69
  70 /* called under bridge lock */
  71 void br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
  72 {
  73         if (should_deliver(to, skb)) {
  74                 __br_deliver(to, skb);
  75                 return;
  76         }
  77
  78         kfree_skb(skb);
  79 }
  80
  81 /* called under bridge lock */
  82 void br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  83 {
  84         if (should_deliver(to, skb)) {
  85                 __br_forward(to, skb);
  86                 return;
  87         }
  88
  89         kfree_skb(skb);
  90 }
  91
  92 /* called under bridge lock */
  93 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone,
  94         void (*__packet_hook)(struct net_bridge_port *p, struct sk_buff *skb))
  95 {
  96         struct net_bridge_port *p;
  97         struct net_bridge_port *prev;
  98
  99         if (clone) {
 100                 struct sk_buff *skb2;
 101
 102                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
 103                         br->statistics.tx_dropped++;
 104                         return;
 105                 }
 106
 107                 skb = skb2;
 108         }
 109
 110         prev = NULL;
 111
 112         p = br->port_list;
 113         while (p != NULL) {
 114                 if (should_deliver(p, skb)) {
 115                         if (prev != NULL) {
 116                                 struct sk_buff *skb2;
 117
 118                                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
 119                                         br->statistics.tx_dropped++;
 120                                         kfree_skb(skb);
 121                                         return;
 122                                 }
 123
 124                                 __packet_hook(prev, skb2);
 125                         }
 126
 127                         prev = p;
 128                 }
 129
 130                 p = p->next;
 131         }
 132
 133         if (prev != NULL) {
 134                 __packet_hook(prev, skb);
 135                 return;
 136         }
 137
 138         kfree_skb(skb);
 139 }
 140
 141 /* called under bridge lock */
 142 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone)
 143 {
 144         br_flood(br, skb, clone, __br_deliver);
 145 }
 146
 147 /* called under bridge lock */
 148 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone)
 149 {
 150         br_flood(br, skb, clone, __br_forward);
 151 }