1 /* 2 * Handle incoming frames 3 * Linux ethernet bridge 4 * 5 * Authors: 6 * Lennert Buytenhek <buytenh@gnu.org> 7 * 8 * $Id: br_input.c,v 1.10 2001/12/24 04:50:20 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/etherdevice.h> 19 #include <linux/netfilter_bridge.h> 20 #include "br_private.h" 21 22 /* Bridge group multicast address 802.1d (pg 51). */ 23 const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; 24 25 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb) 26 { 27 struct net_device *indev; 28 29 br->statistics.rx_packets++; 30 br->statistics.rx_bytes += skb->len; 31 32 indev = skb->dev; 33 skb->dev = br->dev; 34 35 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, 36 netif_receive_skb); 37 } 38 39 /* note: already called with rcu_read_lock (preempt_disabled) */ 40 int br_handle_frame_finish(struct sk_buff *skb) 41 { 42 const unsigned char *dest = eth_hdr(skb)->h_dest; 43 struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); 44 struct net_bridge *br; 45 struct net_bridge_fdb_entry *dst; 46 int passedup = 0; 47 48 if (!p || p->state == BR_STATE_DISABLED) 49 goto drop; 50 51 /* insert into forwarding database after filtering to avoid spoofing */ 52 br = p->br; 53 br_fdb_update(br, p, eth_hdr(skb)->h_source); 54 55 if (p->state == BR_STATE_LEARNING) 56 goto drop; 57 58 if (br->dev->flags & IFF_PROMISC) { 59 struct sk_buff *skb2; 60 61 skb2 = skb_clone(skb, GFP_ATOMIC); 62 if (skb2 != NULL) { 63 passedup = 1; 64 br_pass_frame_up(br, skb2); 65 } 66 } 67 68 if (is_multicast_ether_addr(dest)) { 69 br_flood_forward(br, skb, !passedup); 70 if (!passedup) 71 br_pass_frame_up(br, skb); 72 goto out; 73 } 74 75 dst = __br_fdb_get(br, dest); 76 if (dst != NULL && dst->is_local) { 77 if (!passedup) 78 br_pass_frame_up(br, skb); 79 else 80 kfree_skb(skb); 81 goto out; 82 } 83 84 if (dst != NULL) { 85 br_forward(dst->dst, skb); 86 goto out; 87 } 88 89 br_flood_forward(br, skb, 0); 90 91 out: 92 return 0; 93 drop: 94 kfree_skb(skb); 95 goto out; 96 } 97 98 /* note: already called with rcu_read_lock (preempt_disabled) */ 99 static int br_handle_local_finish(struct sk_buff *skb) 100 { 101 struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); 102 103 if (p && p->state != BR_STATE_DISABLED) 104 br_fdb_update(p->br, p, eth_hdr(skb)->h_source); 105 106 return 0; /* process further */ 107 } 108 109 /* Does address match the link local multicast address. 110 * 01:80:c2:00:00:0X 111 */ 112 static inline int is_link_local(const unsigned char *dest) 113 { 114 return memcmp(dest, br_group_address, 5) == 0 && (dest[5] & 0xf0) == 0; 115 } 116 117 /* 118 * Called via br_handle_frame_hook. 119 * Return 0 if *pskb should be processed furthur 120 * 1 if *pskb is handled 121 * note: already called with rcu_read_lock (preempt_disabled) 122 */ 123 int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb) 124 { 125 struct sk_buff *skb = *pskb; 126 const unsigned char *dest = eth_hdr(skb)->h_dest; 127 128 if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) 129 goto err; 130 131 if (unlikely(is_link_local(dest))) { 132 skb->pkt_type = PACKET_HOST; 133 return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, 134 NULL, br_handle_local_finish) != 0; 135 } 136 137 if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) { 138 if (br_should_route_hook) { 139 if (br_should_route_hook(pskb)) 140 return 0; 141 skb = *pskb; 142 dest = eth_hdr(skb)->h_dest; 143 } 144 145 if (!compare_ether_addr(p->br->dev->dev_addr, dest)) 146 skb->pkt_type = PACKET_HOST; 147 148 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, 149 br_handle_frame_finish); 150 return 1; 151 } 152 153 err: 154 kfree_skb(skb); 155 return 1; 156 } 157