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 /* drop mtu oversized packets except tso */ 35 if (skb->len > skb->dev->mtu && !skb_shinfo(skb)->tso_size) 36 kfree_skb(skb); 37 else { 38 #ifdef CONFIG_BRIDGE_NETFILTER 39 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */ 40 nf_bridge_maybe_copy_header(skb); 41 #endif 42 skb_push(skb, ETH_HLEN); 43 44 dev_queue_xmit(skb); 45 } 46 47 return 0; 48 } 49 50 int br_forward_finish(struct sk_buff *skb) 51 { 52 NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev, 53 br_dev_queue_push_xmit); 54 55 return 0; 56 } 57 58 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 59 { 60 skb->dev = to->dev; 61 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, 62 br_forward_finish); 63 } 64 65 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 66 { 67 struct net_device *indev; 68 69 indev = skb->dev; 70 skb->dev = to->dev; 71 skb->ip_summed = CHECKSUM_NONE; 72 73 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev, 74 br_forward_finish); 75 } 76 77 /* called with rcu_read_lock */ 78 void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 79 { 80 if (should_deliver(to, skb)) { 81 __br_deliver(to, skb); 82 return; 83 } 84 85 kfree_skb(skb); 86 } 87 88 /* called with rcu_read_lock */ 89 void br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 90 { 91 if (should_deliver(to, skb)) { 92 __br_forward(to, skb); 93 return; 94 } 95 96 kfree_skb(skb); 97 } 98 99 /* called under bridge lock */ 100 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone, 101 void (*__packet_hook)(const struct net_bridge_port *p, 102 struct sk_buff *skb)) 103 { 104 struct net_bridge_port *p; 105 struct net_bridge_port *prev; 106 107 if (clone) { 108 struct sk_buff *skb2; 109 110 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 111 br->statistics.tx_dropped++; 112 return; 113 } 114 115 skb = skb2; 116 } 117 118 prev = NULL; 119 120 list_for_each_entry_rcu(p, &br->port_list, list) { 121 if (should_deliver(p, skb)) { 122 if (prev != NULL) { 123 struct sk_buff *skb2; 124 125 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 126 br->statistics.tx_dropped++; 127 kfree_skb(skb); 128 return; 129 } 130 131 __packet_hook(prev, skb2); 132 } 133 134 prev = p; 135 } 136 } 137 138 if (prev != NULL) { 139 __packet_hook(prev, skb); 140 return; 141 } 142 143 kfree_skb(skb); 144 } 145 146 147 /* called with rcu_read_lock */ 148 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone) 149 { 150 br_flood(br, skb, clone, __br_deliver); 151 } 152 153 /* called under bridge lock */ 154 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone) 155 { 156 br_flood(br, skb, clone, __br_forward); 157 } 158