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/skbuff.h> 19 #include <linux/netfilter_bridge.h> 20 #include "br_private.h" 21 22 static inline int should_deliver(const struct net_bridge_port *p, 23 const 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 int br_dev_queue_push_xmit(struct sk_buff *skb) 33 { 34 if (skb->len > skb->dev->mtu) 35 kfree_skb(skb); 36 else { 37 #ifdef CONFIG_BRIDGE_NETFILTER 38 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */ 39 nf_bridge_maybe_copy_header(skb); 40 #endif 41 skb_push(skb, ETH_HLEN); 42 43 dev_queue_xmit(skb); 44 } 45 46 return 0; 47 } 48 49 int br_forward_finish(struct sk_buff *skb) 50 { 51 NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev, 52 br_dev_queue_push_xmit); 53 54 return 0; 55 } 56 57 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 58 { 59 skb->dev = to->dev; 60 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, 61 br_forward_finish); 62 } 63 64 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 65 { 66 struct net_device *indev; 67 68 indev = skb->dev; 69 skb->dev = to->dev; 70 skb->ip_summed = CHECKSUM_NONE; 71 72 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev, 73 br_forward_finish); 74 } 75 76 /* called with rcu_read_lock */ 77 void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 78 { 79 if (should_deliver(to, skb)) { 80 __br_deliver(to, skb); 81 return; 82 } 83 84 kfree_skb(skb); 85 } 86 87 /* called with rcu_read_lock */ 88 void br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 89 { 90 if (should_deliver(to, skb)) { 91 __br_forward(to, skb); 92 return; 93 } 94 95 kfree_skb(skb); 96 } 97 98 /* called under bridge lock */ 99 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone, 100 void (*__packet_hook)(const struct net_bridge_port *p, 101 struct sk_buff *skb)) 102 { 103 struct net_bridge_port *p; 104 struct net_bridge_port *prev; 105 106 if (clone) { 107 struct sk_buff *skb2; 108 109 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 110 br->statistics.tx_dropped++; 111 return; 112 } 113 114 skb = skb2; 115 } 116 117 prev = NULL; 118 119 list_for_each_entry_rcu(p, &br->port_list, list) { 120 if (should_deliver(p, skb)) { 121 if (prev != NULL) { 122 struct sk_buff *skb2; 123 124 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 125 br->statistics.tx_dropped++; 126 kfree_skb(skb); 127 return; 128 } 129 130 __packet_hook(prev, skb2); 131 } 132 133 prev = p; 134 } 135 } 136 137 if (prev != NULL) { 138 __packet_hook(prev, skb); 139 return; 140 } 141 142 kfree_skb(skb); 143 } 144 145 146 /* called with rcu_read_lock */ 147 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone) 148 { 149 br_flood(br, skb, clone, __br_deliver); 150 } 151 152 /* called under bridge lock */ 153 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone) 154 { 155 br_flood(br, skb, clone, __br_forward); 156 } 157