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 1.4 2001/08/14 22:05:57 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/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         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
  53                         __br_forward_finish);
  54 }
  55
  56 static void __br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  57 {
  58         struct net_device *indev;
  59
  60         indev = skb->dev;
  61         skb->dev = to->dev;
  62         skb->ip_summed = CHECKSUM_NONE;
  63
  64         NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
  65                         __br_forward_finish);
  66 }
  67
  68 /* called under bridge lock */
  69 void br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
  70 {
  71         if (should_deliver(to, skb)) {
  72                 __br_deliver(to, skb);
  73                 return;
  74         }
  75
  76         kfree_skb(skb);
  77 }
  78
  79 /* called under bridge lock */
  80 void br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  81 {
  82         if (should_deliver(to, skb)) {
  83                 __br_forward(to, skb);
  84                 return;
  85         }
  86
  87         kfree_skb(skb);
  88 }
  89
  90 /* called under bridge lock */
  91 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone,
  92         void (*__packet_hook)(struct net_bridge_port *p, struct sk_buff *skb))
  93 {
  94         struct net_bridge_port *p;
  95         struct net_bridge_port *prev;
  96
  97         if (clone) {
  98                 struct sk_buff *skb2;
  99
 100                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
 101                         br->statistics.tx_dropped++;
 102                         return;
 103                 }
 104
 105                 skb = skb2;
 106         }
 107
 108         prev = NULL;
 109
 110         p = br->port_list;
 111         while (p != NULL) {
 112                 if (should_deliver(p, skb)) {
 113                         if (prev != NULL) {
 114                                 struct sk_buff *skb2;
 115
 116                                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
 117                                         br->statistics.tx_dropped++;
 118                                         kfree_skb(skb);
 119                                         return;
 120                                 }
 121
 122                                 __packet_hook(prev, skb2);
 123                         }
 124
 125                         prev = p;
 126                 }
 127
 128                 p = p->next;
 129         }
 130
 131         if (prev != NULL) {
 132                 __packet_hook(prev, skb);
 133                 return;
 134         }
 135
 136         kfree_skb(skb);
 137 }
 138
 139 /* called under bridge lock */
 140 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone)
 141 {
 142         br_flood(br, skb, clone, __br_deliver);
 143 }
 144
 145 /* called under bridge lock */
 146 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone)
 147 {
 148         br_flood(br, skb, clone, __br_forward);
 149 }