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 1.2 2000/02/21 15:51:33 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 "br_private.h"
  22
  23 static inline int should_forward(struct net_bridge_port *p, struct sk_buff *skb)
  24 {
  25         if (skb->dev == p->dev ||
  26             p->state != BR_STATE_FORWARDING)
  27                 return 0;
  28
  29         return 1;
  30 }
  31
  32 static void __br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  33 {
  34         skb->dev = to->dev;
  35         dev_queue_xmit(skb);
  36 }
  37
  38 /* called under bridge lock */
  39 void br_forward(struct net_bridge_port *to, struct sk_buff *skb)
  40 {
  41         if (should_forward(to, skb)) {
  42                 __br_forward(to, skb);
  43                 return;
  44         }
  45
  46         kfree_skb(skb);
  47 }
  48
  49 /* called under bridge lock */
  50 void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone)
  51 {
  52         struct net_bridge_port *p;
  53         struct net_bridge_port *prev;
  54
  55         if (clone) {
  56                 struct sk_buff *skb2;
  57
  58                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
  59                         br->statistics.tx_dropped++;
  60                         return;
  61                 }
  62
  63                 skb = skb2;
  64         }
  65
  66         prev = NULL;
  67
  68         p = br->port_list;
  69         while (p != NULL) {
  70                 if (should_forward(p, skb)) {
  71                         if (prev != NULL) {
  72                                 struct sk_buff *skb2;
  73
  74                                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
  75                                         br->statistics.tx_dropped++;
  76                                         kfree_skb(skb);
  77                                         return;
  78                                 }
  79
  80                                 __br_forward(prev, skb2);
  81                         }
  82
  83                         prev = p;
  84                 }
  85
  86                 p = p->next;
  87         }
  88
  89         if (prev != NULL) {
  90                 __br_forward(prev, skb);
  91                 return;
  92         }
  93
  94         kfree_skb(skb);
  95 }