Merge branch 'linus' into pci-for-jesse
[linux-2.6] / net / bridge / br_input.c
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         struct sk_buff *skb2;
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         /* The packet skb2 goes to the local host (NULL to skip). */
59         skb2 = NULL;
60
61         if (br->dev->flags & IFF_PROMISC)
62                 skb2 = skb;
63
64         dst = NULL;
65
66         if (is_multicast_ether_addr(dest)) {
67                 br->statistics.multicast++;
68                 skb2 = skb;
69         } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
70                 skb2 = skb;
71                 /* Do not forward the packet since it's local. */
72                 skb = NULL;
73         }
74
75         if (skb2 == skb)
76                 skb2 = skb_clone(skb, GFP_ATOMIC);
77
78         if (skb2)
79                 br_pass_frame_up(br, skb2);
80
81         if (skb) {
82                 if (dst)
83                         br_forward(dst->dst, skb);
84                 else
85                         br_flood_forward(br, skb);
86         }
87
88 out:
89         return 0;
90 drop:
91         kfree_skb(skb);
92         goto out;
93 }
94
95 /* note: already called with rcu_read_lock (preempt_disabled) */
96 static int br_handle_local_finish(struct sk_buff *skb)
97 {
98         struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
99
100         if (p)
101                 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
102         return 0;        /* process further */
103 }
104
105 /* Does address match the link local multicast address.
106  * 01:80:c2:00:00:0X
107  */
108 static inline int is_link_local(const unsigned char *dest)
109 {
110         __be16 *a = (__be16 *)dest;
111         static const __be16 *b = (const __be16 *)br_group_address;
112         static const __be16 m = cpu_to_be16(0xfff0);
113
114         return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
115 }
116
117 /*
118  * Called via br_handle_frame_hook.
119  * Return NULL if skb is handled
120  * note: already called with rcu_read_lock (preempt_disabled)
121  */
122 struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
123 {
124         const unsigned char *dest = eth_hdr(skb)->h_dest;
125         int (*rhook)(struct sk_buff *skb);
126
127         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
128                 goto drop;
129
130         skb = skb_share_check(skb, GFP_ATOMIC);
131         if (!skb)
132                 return NULL;
133
134         if (unlikely(is_link_local(dest))) {
135                 /* Pause frames shouldn't be passed up by driver anyway */
136                 if (skb->protocol == htons(ETH_P_PAUSE))
137                         goto drop;
138
139                 /* Process STP BPDU's through normal netif_receive_skb() path */
140                 if (p->br->stp_enabled != BR_NO_STP) {
141                         if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
142                                     NULL, br_handle_local_finish))
143                                 return NULL;
144                         else
145                                 return skb;
146                 }
147         }
148
149         switch (p->state) {
150         case BR_STATE_FORWARDING:
151                 rhook = rcu_dereference(br_should_route_hook);
152                 if (rhook != NULL) {
153                         if (rhook(skb))
154                                 return skb;
155                         dest = eth_hdr(skb)->h_dest;
156                 }
157                 /* fall through */
158         case BR_STATE_LEARNING:
159                 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
160                         skb->pkt_type = PACKET_HOST;
161
162                 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
163                         br_handle_frame_finish);
164                 break;
165         default:
166 drop:
167                 kfree_skb(skb);
168         }
169         return NULL;
170 }