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 | ||
5a0e3ad6 | 14 | #include <linux/slab.h> |
1da177e4 LT |
15 | #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 | ||
fda93d92 SH |
21 | /* Bridge group multicast address 802.1d (pg 51). */ |
22 | const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; | |
1da177e4 | 23 | |
68b7c895 | 24 | static int br_pass_frame_up(struct sk_buff *skb) |
1da177e4 | 25 | { |
68b7c895 | 26 | struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; |
1da177e4 | 27 | |
a339f1c8 PE |
28 | brdev->stats.rx_packets++; |
29 | brdev->stats.rx_bytes += skb->len; | |
1da177e4 LT |
30 | |
31 | indev = skb->dev; | |
a339f1c8 | 32 | skb->dev = brdev; |
1da177e4 | 33 | |
68b7c895 HX |
34 | return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
35 | netif_receive_skb); | |
1da177e4 LT |
36 | } |
37 | ||
38 | /* note: already called with rcu_read_lock (preempt_disabled) */ | |
39 | int br_handle_frame_finish(struct sk_buff *skb) | |
40 | { | |
41 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
b3f1be4b SH |
42 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); |
43 | struct net_bridge *br; | |
1da177e4 | 44 | struct net_bridge_fdb_entry *dst; |
c4fcb78c | 45 | struct net_bridge_mdb_entry *mdst; |
e081e1e3 | 46 | struct sk_buff *skb2; |
1da177e4 | 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 | |
c4fcb78c HX |
55 | if (is_multicast_ether_addr(dest) && |
56 | br_multicast_rcv(br, p, skb)) | |
57 | goto drop; | |
58 | ||
b3f1be4b SH |
59 | if (p->state == BR_STATE_LEARNING) |
60 | goto drop; | |
0e5eabac | 61 | |
68b7c895 HX |
62 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
63 | ||
e081e1e3 HX |
64 | /* The packet skb2 goes to the local host (NULL to skip). */ |
65 | skb2 = NULL; | |
1da177e4 | 66 | |
e081e1e3 HX |
67 | if (br->dev->flags & IFF_PROMISC) |
68 | skb2 = skb; | |
69 | ||
70 | dst = NULL; | |
1da177e4 | 71 | |
dbbc0988 | 72 | if (is_multicast_ether_addr(dest)) { |
c4fcb78c | 73 | mdst = br_mdb_get(br, skb); |
32dec5dd | 74 | if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
c4fcb78c HX |
75 | if ((mdst && !hlist_unhashed(&mdst->mglist)) || |
76 | br_multicast_is_router(br)) | |
77 | skb2 = skb; | |
78 | br_multicast_forward(mdst, skb, skb2); | |
79 | skb = NULL; | |
80 | if (!skb2) | |
81 | goto out; | |
82 | } else | |
83 | skb2 = skb; | |
84 | ||
a339f1c8 | 85 | br->dev->stats.multicast++; |
e081e1e3 HX |
86 | } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
87 | skb2 = skb; | |
88 | /* Do not forward the packet since it's local. */ | |
89 | skb = NULL; | |
1da177e4 LT |
90 | } |
91 | ||
e081e1e3 HX |
92 | if (skb) { |
93 | if (dst) | |
7f7708f0 | 94 | br_forward(dst->dst, skb, skb2); |
e081e1e3 | 95 | else |
b33084be | 96 | br_flood_forward(br, skb, skb2); |
e081e1e3 | 97 | } |
1da177e4 | 98 | |
87557c18 | 99 | if (skb2) |
68b7c895 | 100 | return br_pass_frame_up(skb2); |
87557c18 | 101 | |
1da177e4 LT |
102 | out: |
103 | return 0; | |
b3f1be4b SH |
104 | drop: |
105 | kfree_skb(skb); | |
106 | goto out; | |
1da177e4 LT |
107 | } |
108 | ||
cf0f02d0 SH |
109 | /* note: already called with rcu_read_lock (preempt_disabled) */ |
110 | static int br_handle_local_finish(struct sk_buff *skb) | |
111 | { | |
112 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); | |
113 | ||
df1c0b84 | 114 | if (p) |
cf0f02d0 | 115 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
cf0f02d0 SH |
116 | return 0; /* process further */ |
117 | } | |
118 | ||
119 | /* Does address match the link local multicast address. | |
120 | * 01:80:c2:00:00:0X | |
121 | */ | |
b3e83d6d | 122 | static inline int is_link_local(const unsigned char *dest) |
cf0f02d0 | 123 | { |
582ee43d AV |
124 | __be16 *a = (__be16 *)dest; |
125 | static const __be16 *b = (const __be16 *)br_group_address; | |
91c5ec3e | 126 | static const __be16 m = cpu_to_be16(0xfff0); |
fd74e6cc SH |
127 | |
128 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; | |
cf0f02d0 SH |
129 | } |
130 | ||
1da177e4 LT |
131 | /* |
132 | * Called via br_handle_frame_hook. | |
6229e362 | 133 | * Return NULL if skb is handled |
9d6f229f | 134 | * note: already called with rcu_read_lock (preempt_disabled) |
1da177e4 | 135 | */ |
6229e362 | 136 | struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb) |
1da177e4 | 137 | { |
1da177e4 | 138 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
82de382c | 139 | int (*rhook)(struct sk_buff *skb); |
1da177e4 | 140 | |
1da177e4 | 141 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 142 | goto drop; |
1da177e4 | 143 | |
7b995651 HX |
144 | skb = skb_share_check(skb, GFP_ATOMIC); |
145 | if (!skb) | |
146 | return NULL; | |
147 | ||
2111f8b9 SH |
148 | if (unlikely(is_link_local(dest))) { |
149 | /* Pause frames shouldn't be passed up by driver anyway */ | |
150 | if (skb->protocol == htons(ETH_P_PAUSE)) | |
151 | goto drop; | |
152 | ||
a598f6ae SH |
153 | /* If STP is turned off, then forward */ |
154 | if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0) | |
155 | goto forward; | |
156 | ||
43aa1920 SH |
157 | if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
158 | NULL, br_handle_local_finish)) | |
159 | return NULL; /* frame consumed by filter */ | |
160 | else | |
161 | return skb; /* continue processing */ | |
2111f8b9 | 162 | } |
1da177e4 | 163 | |
a598f6ae | 164 | forward: |
467aea0d SH |
165 | switch (p->state) { |
166 | case BR_STATE_FORWARDING: | |
82de382c PE |
167 | rhook = rcu_dereference(br_should_route_hook); |
168 | if (rhook != NULL) { | |
169 | if (rhook(skb)) | |
6229e362 | 170 | return skb; |
1da177e4 LT |
171 | dest = eth_hdr(skb)->h_dest; |
172 | } | |
467aea0d SH |
173 | /* fall through */ |
174 | case BR_STATE_LEARNING: | |
6ede2463 | 175 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
176 | skb->pkt_type = PACKET_HOST; |
177 | ||
178 | NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, | |
179 | br_handle_frame_finish); | |
467aea0d SH |
180 | break; |
181 | default: | |
182 | drop: | |
183 | kfree_skb(skb); | |
1da177e4 | 184 | } |
6229e362 | 185 | return NULL; |
1da177e4 | 186 | } |