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/if_vlan.h> 20 #include <linux/netfilter_bridge.h> 21 #include "br_private.h" 22 23 static inline int should_deliver(const struct net_bridge_port *p, 24 const 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 inline unsigned packet_length(const struct sk_buff *skb) 34 { 35 return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0); 36 } 37 38 int br_dev_queue_push_xmit(struct sk_buff *skb) 39 { 40 /* drop mtu oversized packets except tso */ 41 if (packet_length(skb) > skb->dev->mtu && !skb_shinfo(skb)->tso_size) 42 kfree_skb(skb); 43 else { 44 #ifdef CONFIG_BRIDGE_NETFILTER 45 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */ 46 nf_bridge_maybe_copy_header(skb); 47 #endif 48 skb_push(skb, ETH_HLEN); 49 50 dev_queue_xmit(skb); 51 } 52 53 return 0; 54 } 55 56 int br_forward_finish(struct sk_buff *skb) 57 { 58 NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev, 59 br_dev_queue_push_xmit); 60 61 return 0; 62 } 63 64 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 65 { 66 skb->dev = to->dev; 67 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, 68 br_forward_finish); 69 } 70 71 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 72 { 73 struct net_device *indev; 74 75 indev = skb->dev; 76 skb->dev = to->dev; 77 skb->ip_summed = CHECKSUM_NONE; 78 79 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev, 80 br_forward_finish); 81 } 82 83 /* called with rcu_read_lock */ 84 void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) 85 { 86 if (should_deliver(to, skb)) { 87 __br_deliver(to, skb); 88 return; 89 } 90 91 kfree_skb(skb); 92 } 93 94 /* called with rcu_read_lock */ 95 void br_forward(const struct net_bridge_port *to, struct sk_buff *skb) 96 { 97 if (should_deliver(to, skb)) { 98 __br_forward(to, skb); 99 return; 100 } 101 102 kfree_skb(skb); 103 } 104 105 /* called under bridge lock */ 106 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone, 107 void (*__packet_hook)(const struct net_bridge_port *p, 108 struct sk_buff *skb)) 109 { 110 struct net_bridge_port *p; 111 struct net_bridge_port *prev; 112 113 if (clone) { 114 struct sk_buff *skb2; 115 116 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 117 br->statistics.tx_dropped++; 118 return; 119 } 120 121 skb = skb2; 122 } 123 124 prev = NULL; 125 126 list_for_each_entry_rcu(p, &br->port_list, list) { 127 if (should_deliver(p, skb)) { 128 if (prev != NULL) { 129 struct sk_buff *skb2; 130 131 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { 132 br->statistics.tx_dropped++; 133 kfree_skb(skb); 134 return; 135 } 136 137 __packet_hook(prev, skb2); 138 } 139 140 prev = p; 141 } 142 } 143 144 if (prev != NULL) { 145 __packet_hook(prev, skb); 146 return; 147 } 148 149 kfree_skb(skb); 150 } 151 152 153 /* called with rcu_read_lock */ 154 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone) 155 { 156 br_flood(br, skb, clone, __br_deliver); 157 } 158 159 /* called under bridge lock */ 160 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone) 161 { 162 br_flood(br, skb, clone, __br_forward); 163 } 164