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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Handle incoming frames
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090014#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/kernel.h>
16#include <linux/netdevice.h>
17#include <linux/etherdevice.h>
18#include <linux/netfilter_bridge.h>
19#include "br_private.h"
20
Stephen Hemmingerfda93d92006-03-20 22:59:21 -080021/* Bridge group multicast address 802.1d (pg 51). */
22const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Herbert Xu68b7c892010-02-27 19:41:40 +000024static int br_pass_frame_up(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070025{
Herbert Xu68b7c892010-02-27 19:41:40 +000026 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
stephen hemminger14bb4782010-03-02 13:32:09 +000027 struct net_bridge *br = netdev_priv(brdev);
28 struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Eric Dumazet406818f2010-06-23 13:00:48 -070030 u64_stats_update_begin(&brstats->syncp);
stephen hemminger14bb4782010-03-02 13:32:09 +000031 brstats->rx_packets++;
32 brstats->rx_bytes += skb->len;
Eric Dumazet406818f2010-06-23 13:00:48 -070033 u64_stats_update_end(&brstats->syncp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35 indev = skb->dev;
Pavel Emelyanova339f1c2008-05-21 14:13:47 -070036 skb->dev = brdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Jan Engelhardt713aefa2010-03-23 04:07:21 +010038 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
Herbert Xu68b7c892010-02-27 19:41:40 +000039 netif_receive_skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040}
41
stephen hemmingereeaf61d2010-07-27 08:26:30 +000042/* note: already called with rcu_read_lock */
Linus Torvalds1da177e2005-04-16 15:20:36 -070043int br_handle_frame_finish(struct sk_buff *skb)
44{
45 const unsigned char *dest = eth_hdr(skb)->h_dest;
Jiri Pirkof350a0a2010-06-15 06:50:45 +000046 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
Stephen Hemmingerb3f1be42006-02-09 17:08:52 -080047 struct net_bridge *br;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 struct net_bridge_fdb_entry *dst;
Herbert Xuc4fcb782010-02-27 19:41:48 +000049 struct net_bridge_mdb_entry *mdst;
Herbert Xue081e1e2007-09-16 16:20:48 -070050 struct sk_buff *skb2;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
Stephen Hemmingerb3f1be42006-02-09 17:08:52 -080052 if (!p || p->state == BR_STATE_DISABLED)
53 goto drop;
Stephen Hemminger85967bb2005-05-29 14:15:55 -070054
Stephen Hemmingerb3f1be42006-02-09 17:08:52 -080055 /* insert into forwarding database after filtering to avoid spoofing */
56 br = p->br;
57 br_fdb_update(br, p, eth_hdr(skb)->h_source);
58
Herbert Xuc4fcb782010-02-27 19:41:48 +000059 if (is_multicast_ether_addr(dest) &&
60 br_multicast_rcv(br, p, skb))
61 goto drop;
62
Stephen Hemmingerb3f1be42006-02-09 17:08:52 -080063 if (p->state == BR_STATE_LEARNING)
64 goto drop;
Stephen Hemminger0e5eaba2005-12-21 19:00:18 -080065
Herbert Xu68b7c892010-02-27 19:41:40 +000066 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
67
Herbert Xue081e1e2007-09-16 16:20:48 -070068 /* The packet skb2 goes to the local host (NULL to skip). */
69 skb2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Herbert Xue081e1e2007-09-16 16:20:48 -070071 if (br->dev->flags & IFF_PROMISC)
72 skb2 = skb;
73
74 dst = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Kris Katterjohndbbc0982006-01-06 13:05:58 -080076 if (is_multicast_ether_addr(dest)) {
Herbert Xuc4fcb782010-02-27 19:41:48 +000077 mdst = br_mdb_get(br, skb);
YOSHIFUJI Hideaki / 吉藤英明32dec5d2010-03-15 21:51:18 +000078 if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) {
Herbert Xuc4fcb782010-02-27 19:41:48 +000079 if ((mdst && !hlist_unhashed(&mdst->mglist)) ||
80 br_multicast_is_router(br))
81 skb2 = skb;
82 br_multicast_forward(mdst, skb, skb2);
83 skb = NULL;
84 if (!skb2)
85 goto out;
86 } else
87 skb2 = skb;
88
Pavel Emelyanova339f1c2008-05-21 14:13:47 -070089 br->dev->stats.multicast++;
Herbert Xue081e1e2007-09-16 16:20:48 -070090 } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
91 skb2 = skb;
92 /* Do not forward the packet since it's local. */
93 skb = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 }
95
Herbert Xue081e1e2007-09-16 16:20:48 -070096 if (skb) {
97 if (dst)
Michael Braun7f7708f2010-03-16 00:26:22 -070098 br_forward(dst->dst, skb, skb2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 else
Herbert Xub33084b2010-02-27 19:41:41 +0000100 br_flood_forward(br, skb, skb2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 }
102
Herbert Xu87557c12010-02-27 19:41:39 +0000103 if (skb2)
Herbert Xu68b7c892010-02-27 19:41:40 +0000104 return br_pass_frame_up(skb2);
Herbert Xu87557c12010-02-27 19:41:39 +0000105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106out:
107 return 0;
Stephen Hemmingerb3f1be42006-02-09 17:08:52 -0800108drop:
109 kfree_skb(skb);
110 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111}
112
stephen hemmingereeaf61d2010-07-27 08:26:30 +0000113/* note: already called with rcu_read_lock */
Stephen Hemmingercf0f02d2006-03-20 22:59:06 -0800114static int br_handle_local_finish(struct sk_buff *skb)
115{
Jiri Pirkof350a0a2010-06-15 06:50:45 +0000116 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
Stephen Hemmingercf0f02d2006-03-20 22:59:06 -0800117
Jiri Pirkof350a0a2010-06-15 06:50:45 +0000118 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
Stephen Hemmingercf0f02d2006-03-20 22:59:06 -0800119 return 0; /* process further */
120}
121
122/* Does address match the link local multicast address.
123 * 01:80:c2:00:00:0X
124 */
Andrew Mortonb3e83d62006-03-20 23:00:56 -0800125static inline int is_link_local(const unsigned char *dest)
Stephen Hemmingercf0f02d2006-03-20 22:59:06 -0800126{
Al Viro582ee432007-07-26 17:33:39 +0100127 __be16 *a = (__be16 *)dest;
128 static const __be16 *b = (const __be16 *)br_group_address;
YOSHIFUJI Hideaki91c5ec32007-12-12 03:51:03 +0900129 static const __be16 m = cpu_to_be16(0xfff0);
Stephen Hemmingerfd74e6c2007-03-12 16:25:32 -0700130
131 return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
Stephen Hemmingercf0f02d2006-03-20 22:59:06 -0800132}
133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134/*
Stephen Hemminger6229e362007-03-21 13:38:47 -0700135 * Return NULL if skb is handled
stephen hemmingereeaf61d2010-07-27 08:26:30 +0000136 * note: already called with rcu_read_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 */
Jiri Pirkoab95bfe2010-06-01 21:52:08 +0000138struct sk_buff *br_handle_frame(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
Jiri Pirkoab95bfe2010-06-01 21:52:08 +0000140 struct net_bridge_port *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 const unsigned char *dest = eth_hdr(skb)->h_dest;
Pavel Emelyanov82de3822007-11-29 23:58:58 +1100142 int (*rhook)(struct sk_buff *skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Simon Hormanc2368e72010-08-22 17:35:32 +0000144 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
Jiri Pirkoab95bfe2010-06-01 21:52:08 +0000145 return skb;
146
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
Stephen Hemminger467aea02007-03-21 13:42:06 -0700148 goto drop;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149
Herbert Xu7b995652007-10-14 00:39:01 -0700150 skb = skb_share_check(skb, GFP_ATOMIC);
151 if (!skb)
152 return NULL;
153
Jiri Pirkof350a0a2010-06-15 06:50:45 +0000154 p = br_port_get_rcu(skb->dev);
Jiri Pirkoab95bfe2010-06-01 21:52:08 +0000155
Stephen Hemminger2111f8b2007-04-25 22:05:55 -0700156 if (unlikely(is_link_local(dest))) {
157 /* Pause frames shouldn't be passed up by driver anyway */
158 if (skb->protocol == htons(ETH_P_PAUSE))
159 goto drop;
160
Stephen Hemmingera598f6a2009-05-15 06:10:13 +0000161 /* If STP is turned off, then forward */
Benjamin Poirier1e253c32010-10-18 16:09:35 +0000162 if (p->br->stp_enabled == BR_NO_STP)
Stephen Hemmingera598f6a2009-05-15 06:10:13 +0000163 goto forward;
164
Jan Engelhardt713aefa2010-03-23 04:07:21 +0100165 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
Stephen Hemminger43aa1922008-06-17 16:09:45 -0700166 NULL, br_handle_local_finish))
167 return NULL; /* frame consumed by filter */
168 else
169 return skb; /* continue processing */
Stephen Hemminger2111f8b2007-04-25 22:05:55 -0700170 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
Stephen Hemmingera598f6a2009-05-15 06:10:13 +0000172forward:
Stephen Hemminger467aea02007-03-21 13:42:06 -0700173 switch (p->state) {
174 case BR_STATE_FORWARDING:
Pavel Emelyanov82de3822007-11-29 23:58:58 +1100175 rhook = rcu_dereference(br_should_route_hook);
176 if (rhook != NULL) {
177 if (rhook(skb))
Stephen Hemminger6229e362007-03-21 13:38:47 -0700178 return skb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 dest = eth_hdr(skb)->h_dest;
180 }
Stephen Hemminger467aea02007-03-21 13:42:06 -0700181 /* fall through */
182 case BR_STATE_LEARNING:
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700183 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 skb->pkt_type = PACKET_HOST;
185
Jan Engelhardt713aefa2010-03-23 04:07:21 +0100186 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 br_handle_frame_finish);
Stephen Hemminger467aea02007-03-21 13:42:06 -0700188 break;
189 default:
190drop:
191 kfree_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 }
Stephen Hemminger6229e362007-03-21 13:38:47 -0700193 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194}