Commit | Line | Data |
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1da177e4 LT |
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 | ||
fda93d92 SH |
22 | /* Bridge group multicast address 802.1d (pg 51). */ |
23 | const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; | |
1da177e4 | 24 | |
1da177e4 LT |
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, | |
d5513a7d | 36 | netif_receive_skb); |
1da177e4 LT |
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; | |
b3f1be4b SH |
43 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); |
44 | struct net_bridge *br; | |
1da177e4 LT |
45 | struct net_bridge_fdb_entry *dst; |
46 | int passedup = 0; | |
47 | ||
b3f1be4b SH |
48 | if (!p || p->state == BR_STATE_DISABLED) |
49 | goto drop; | |
50 | ||
85967bb4 | 51 | /* insert into forwarding database after filtering to avoid spoofing */ |
b3f1be4b SH |
52 | br = p->br; |
53 | br_fdb_update(br, p, eth_hdr(skb)->h_source); | |
85967bb4 | 54 | |
b3f1be4b SH |
55 | if (p->state == BR_STATE_LEARNING) |
56 | goto drop; | |
0e5eabac | 57 | |
1da177e4 LT |
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 | ||
dbbc0988 | 68 | if (is_multicast_ether_addr(dest)) { |
1c29fc49 | 69 | br->statistics.multicast++; |
1da177e4 LT |
70 | br_flood_forward(br, skb, !passedup); |
71 | if (!passedup) | |
72 | br_pass_frame_up(br, skb); | |
73 | goto out; | |
74 | } | |
75 | ||
76 | dst = __br_fdb_get(br, dest); | |
77 | if (dst != NULL && dst->is_local) { | |
78 | if (!passedup) | |
79 | br_pass_frame_up(br, skb); | |
80 | else | |
81 | kfree_skb(skb); | |
82 | goto out; | |
83 | } | |
84 | ||
85 | if (dst != NULL) { | |
86 | br_forward(dst->dst, skb); | |
87 | goto out; | |
88 | } | |
89 | ||
90 | br_flood_forward(br, skb, 0); | |
91 | ||
92 | out: | |
93 | return 0; | |
b3f1be4b SH |
94 | drop: |
95 | kfree_skb(skb); | |
96 | goto out; | |
1da177e4 LT |
97 | } |
98 | ||
cf0f02d0 SH |
99 | /* note: already called with rcu_read_lock (preempt_disabled) */ |
100 | static int br_handle_local_finish(struct sk_buff *skb) | |
101 | { | |
102 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); | |
103 | ||
104 | if (p && p->state != BR_STATE_DISABLED) | |
105 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); | |
106 | ||
107 | return 0; /* process further */ | |
108 | } | |
109 | ||
110 | /* Does address match the link local multicast address. | |
111 | * 01:80:c2:00:00:0X | |
112 | */ | |
b3e83d6d | 113 | static inline int is_link_local(const unsigned char *dest) |
cf0f02d0 | 114 | { |
fd74e6cc SH |
115 | const u16 *a = (const u16 *) dest; |
116 | static const u16 *const b = (const u16 *const ) br_group_address; | |
117 | static const u16 m = __constant_cpu_to_be16(0xfff0); | |
118 | ||
119 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; | |
cf0f02d0 SH |
120 | } |
121 | ||
1da177e4 LT |
122 | /* |
123 | * Called via br_handle_frame_hook. | |
6229e362 | 124 | * Return NULL if skb is handled |
9d6f229f | 125 | * note: already called with rcu_read_lock (preempt_disabled) |
1da177e4 | 126 | */ |
6229e362 | 127 | struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb) |
1da177e4 | 128 | { |
1da177e4 LT |
129 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
130 | ||
1da177e4 | 131 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 132 | goto drop; |
1da177e4 | 133 | |
2111f8b9 SH |
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 | ||
c2886d62 SH |
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 | } | |
2111f8b9 | 147 | } |
1da177e4 | 148 | |
467aea0d SH |
149 | switch (p->state) { |
150 | case BR_STATE_FORWARDING: | |
151 | ||
1da177e4 | 152 | if (br_should_route_hook) { |
6229e362 SH |
153 | if (br_should_route_hook(&skb)) |
154 | return skb; | |
1da177e4 LT |
155 | dest = eth_hdr(skb)->h_dest; |
156 | } | |
467aea0d SH |
157 | /* fall through */ |
158 | case BR_STATE_LEARNING: | |
6ede2463 | 159 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
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); | |
467aea0d SH |
164 | break; |
165 | default: | |
166 | drop: | |
167 | kfree_skb(skb); | |
1da177e4 | 168 | } |
6229e362 | 169 | return NULL; |
1da177e4 | 170 | } |