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