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 | * | |
1da177e4 LT |
8 | * 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 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/netdevice.h> | |
16 | #include <linux/etherdevice.h> | |
17 | #include <linux/netfilter_bridge.h> | |
18 | #include "br_private.h" | |
19 | ||
fda93d92 SH |
20 | /* Bridge group multicast address 802.1d (pg 51). */ |
21 | const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; | |
1da177e4 | 22 | |
68b7c895 | 23 | static int br_pass_frame_up(struct sk_buff *skb) |
1da177e4 | 24 | { |
68b7c895 | 25 | struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; |
1da177e4 | 26 | |
a339f1c8 PE |
27 | brdev->stats.rx_packets++; |
28 | brdev->stats.rx_bytes += skb->len; | |
1da177e4 LT |
29 | |
30 | indev = skb->dev; | |
a339f1c8 | 31 | skb->dev = brdev; |
1da177e4 | 32 | |
68b7c895 HX |
33 | return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
34 | netif_receive_skb); | |
1da177e4 LT |
35 | } |
36 | ||
37 | /* note: already called with rcu_read_lock (preempt_disabled) */ | |
38 | int br_handle_frame_finish(struct sk_buff *skb) | |
39 | { | |
40 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
b3f1be4b SH |
41 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); |
42 | struct net_bridge *br; | |
1da177e4 | 43 | struct net_bridge_fdb_entry *dst; |
c4fcb78c | 44 | struct net_bridge_mdb_entry *mdst; |
e081e1e3 | 45 | struct sk_buff *skb2; |
1da177e4 | 46 | |
b3f1be4b SH |
47 | if (!p || p->state == BR_STATE_DISABLED) |
48 | goto drop; | |
49 | ||
85967bb4 | 50 | /* insert into forwarding database after filtering to avoid spoofing */ |
b3f1be4b SH |
51 | br = p->br; |
52 | br_fdb_update(br, p, eth_hdr(skb)->h_source); | |
85967bb4 | 53 | |
c4fcb78c HX |
54 | if (is_multicast_ether_addr(dest) && |
55 | br_multicast_rcv(br, p, skb)) | |
56 | goto drop; | |
57 | ||
b3f1be4b SH |
58 | if (p->state == BR_STATE_LEARNING) |
59 | goto drop; | |
0e5eabac | 60 | |
68b7c895 HX |
61 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
62 | ||
e081e1e3 HX |
63 | /* The packet skb2 goes to the local host (NULL to skip). */ |
64 | skb2 = NULL; | |
1da177e4 | 65 | |
e081e1e3 HX |
66 | if (br->dev->flags & IFF_PROMISC) |
67 | skb2 = skb; | |
68 | ||
69 | dst = NULL; | |
1da177e4 | 70 | |
dbbc0988 | 71 | if (is_multicast_ether_addr(dest)) { |
c4fcb78c | 72 | mdst = br_mdb_get(br, skb); |
32dec5dd | 73 | if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
c4fcb78c HX |
74 | if ((mdst && !hlist_unhashed(&mdst->mglist)) || |
75 | br_multicast_is_router(br)) | |
76 | skb2 = skb; | |
77 | br_multicast_forward(mdst, skb, skb2); | |
78 | skb = NULL; | |
79 | if (!skb2) | |
80 | goto out; | |
81 | } else | |
82 | skb2 = skb; | |
83 | ||
a339f1c8 | 84 | br->dev->stats.multicast++; |
e081e1e3 HX |
85 | } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
86 | skb2 = skb; | |
87 | /* Do not forward the packet since it's local. */ | |
88 | skb = NULL; | |
1da177e4 LT |
89 | } |
90 | ||
e081e1e3 HX |
91 | if (skb) { |
92 | if (dst) | |
7f7708f0 | 93 | br_forward(dst->dst, skb, skb2); |
e081e1e3 | 94 | else |
b33084be | 95 | br_flood_forward(br, skb, skb2); |
e081e1e3 | 96 | } |
1da177e4 | 97 | |
87557c18 | 98 | if (skb2) |
68b7c895 | 99 | return br_pass_frame_up(skb2); |
87557c18 | 100 | |
1da177e4 LT |
101 | out: |
102 | return 0; | |
b3f1be4b SH |
103 | drop: |
104 | kfree_skb(skb); | |
105 | goto out; | |
1da177e4 LT |
106 | } |
107 | ||
cf0f02d0 SH |
108 | /* note: already called with rcu_read_lock (preempt_disabled) */ |
109 | static int br_handle_local_finish(struct sk_buff *skb) | |
110 | { | |
111 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); | |
112 | ||
df1c0b84 | 113 | if (p) |
cf0f02d0 | 114 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
cf0f02d0 SH |
115 | return 0; /* process further */ |
116 | } | |
117 | ||
118 | /* Does address match the link local multicast address. | |
119 | * 01:80:c2:00:00:0X | |
120 | */ | |
b3e83d6d | 121 | static inline int is_link_local(const unsigned char *dest) |
cf0f02d0 | 122 | { |
582ee43d AV |
123 | __be16 *a = (__be16 *)dest; |
124 | static const __be16 *b = (const __be16 *)br_group_address; | |
91c5ec3e | 125 | static const __be16 m = cpu_to_be16(0xfff0); |
fd74e6cc SH |
126 | |
127 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; | |
cf0f02d0 SH |
128 | } |
129 | ||
1da177e4 LT |
130 | /* |
131 | * Called via br_handle_frame_hook. | |
6229e362 | 132 | * Return NULL if skb is handled |
9d6f229f | 133 | * note: already called with rcu_read_lock (preempt_disabled) |
1da177e4 | 134 | */ |
6229e362 | 135 | struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb) |
1da177e4 | 136 | { |
1da177e4 | 137 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
82de382c | 138 | int (*rhook)(struct sk_buff *skb); |
1da177e4 | 139 | |
1da177e4 | 140 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 141 | goto drop; |
1da177e4 | 142 | |
7b995651 HX |
143 | skb = skb_share_check(skb, GFP_ATOMIC); |
144 | if (!skb) | |
145 | return NULL; | |
146 | ||
2111f8b9 SH |
147 | if (unlikely(is_link_local(dest))) { |
148 | /* Pause frames shouldn't be passed up by driver anyway */ | |
149 | if (skb->protocol == htons(ETH_P_PAUSE)) | |
150 | goto drop; | |
151 | ||
a598f6ae SH |
152 | /* If STP is turned off, then forward */ |
153 | if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0) | |
154 | goto forward; | |
155 | ||
43aa1920 SH |
156 | if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
157 | NULL, br_handle_local_finish)) | |
158 | return NULL; /* frame consumed by filter */ | |
159 | else | |
160 | return skb; /* continue processing */ | |
2111f8b9 | 161 | } |
1da177e4 | 162 | |
a598f6ae | 163 | forward: |
467aea0d SH |
164 | switch (p->state) { |
165 | case BR_STATE_FORWARDING: | |
82de382c PE |
166 | rhook = rcu_dereference(br_should_route_hook); |
167 | if (rhook != NULL) { | |
168 | if (rhook(skb)) | |
6229e362 | 169 | return skb; |
1da177e4 LT |
170 | dest = eth_hdr(skb)->h_dest; |
171 | } | |
467aea0d SH |
172 | /* fall through */ |
173 | case BR_STATE_LEARNING: | |
6ede2463 | 174 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
175 | skb->pkt_type = PACKET_HOST; |
176 | ||
177 | NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, | |
178 | br_handle_frame_finish); | |
467aea0d SH |
179 | break; |
180 | default: | |
181 | drop: | |
182 | kfree_skb(skb); | |
1da177e4 | 183 | } |
6229e362 | 184 | return NULL; |
1da177e4 | 185 | } |