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 const unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; 23 24 static int br_pass_frame_up_finish(struct sk_buff *skb) 25 { 26 netif_receive_skb(skb); 27 return 0; 28 } 29 30 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb) 31 { 32 struct net_device *indev; 33 34 br->statistics.rx_packets++; 35 br->statistics.rx_bytes += skb->len; 36 37 indev = skb->dev; 38 skb->dev = br->dev; 39 40 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, 41 br_pass_frame_up_finish); 42 } 43 44 /* note: already called with rcu_read_lock (preempt_disabled) */ 45 int br_handle_frame_finish(struct sk_buff *skb) 46 { 47 const unsigned char *dest = eth_hdr(skb)->h_dest; 48 struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); 49 struct net_bridge *br; 50 struct net_bridge_fdb_entry *dst; 51 int passedup = 0; 52 53 if (!p || p->state == BR_STATE_DISABLED) 54 goto drop; 55 56 /* insert into forwarding database after filtering to avoid spoofing */ 57 br = p->br; 58 br_fdb_update(br, p, eth_hdr(skb)->h_source); 59 60 if (p->state == BR_STATE_LEARNING) 61 goto drop; 62 63 if (br->dev->flags & IFF_PROMISC) { 64 struct sk_buff *skb2; 65 66 skb2 = skb_clone(skb, GFP_ATOMIC); 67 if (skb2 != NULL) { 68 passedup = 1; 69 br_pass_frame_up(br, skb2); 70 } 71 } 72 73 if (is_multicast_ether_addr(dest)) { 74 br_flood_forward(br, skb, !passedup); 75 if (!passedup) 76 br_pass_frame_up(br, skb); 77 goto out; 78 } 79 80 dst = __br_fdb_get(br, dest); 81 if (dst != NULL && dst->is_local) { 82 if (!passedup) 83 br_pass_frame_up(br, skb); 84 else 85 kfree_skb(skb); 86 goto out; 87 } 88 89 if (dst != NULL) { 90 br_forward(dst->dst, skb); 91 goto out; 92 } 93 94 br_flood_forward(br, skb, 0); 95 96 out: 97 return 0; 98 drop: 99 kfree_skb(skb); 100 goto out; 101 } 102 103 /* 104 * Called via br_handle_frame_hook. 105 * Return 0 if *pskb should be processed furthur 106 * 1 if *pskb is handled 107 * note: already called with rcu_read_lock (preempt_disabled) 108 */ 109 int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb) 110 { 111 struct sk_buff *skb = *pskb; 112 const unsigned char *dest = eth_hdr(skb)->h_dest; 113 114 if (p->state == BR_STATE_DISABLED) 115 goto err; 116 117 if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) 118 goto err; 119 120 if (p->br->stp_enabled && 121 !memcmp(dest, bridge_ula, 5) && 122 !(dest[5] & 0xF0)) { 123 if (!dest[5]) { 124 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, 125 NULL, br_stp_handle_bpdu); 126 return 1; 127 } 128 goto err; 129 } 130 131 if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) { 132 if (br_should_route_hook) { 133 if (br_should_route_hook(pskb)) 134 return 0; 135 skb = *pskb; 136 dest = eth_hdr(skb)->h_dest; 137 } 138 139 if (!compare_ether_addr(p->br->dev->dev_addr, dest)) 140 skb->pkt_type = PACKET_HOST; 141 142 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, 143 br_handle_frame_finish); 144 return 1; 145 } 146 147 err: 148 kfree_skb(skb); 149 return 1; 150 } 151