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; |
14bb4789 | 26 | struct net_bridge *br = netdev_priv(brdev); |
27 | struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats); | |
1da177e4 | 28 | |
14bb4789 | 29 | brstats->rx_packets++; |
30 | brstats->rx_bytes += skb->len; | |
1da177e4 LT |
31 | |
32 | indev = skb->dev; | |
a339f1c8 | 33 | skb->dev = brdev; |
1da177e4 | 34 | |
68b7c895 HX |
35 | return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
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 | 45 | struct net_bridge_fdb_entry *dst; |
c4fcb78c | 46 | struct net_bridge_mdb_entry *mdst; |
e081e1e3 | 47 | struct sk_buff *skb2; |
1da177e4 | 48 | |
b3f1be4b SH |
49 | if (!p || p->state == BR_STATE_DISABLED) |
50 | goto drop; | |
51 | ||
85967bb4 | 52 | /* insert into forwarding database after filtering to avoid spoofing */ |
b3f1be4b SH |
53 | br = p->br; |
54 | br_fdb_update(br, p, eth_hdr(skb)->h_source); | |
85967bb4 | 55 | |
c4fcb78c HX |
56 | if (is_multicast_ether_addr(dest) && |
57 | br_multicast_rcv(br, p, skb)) | |
58 | goto drop; | |
59 | ||
b3f1be4b SH |
60 | if (p->state == BR_STATE_LEARNING) |
61 | goto drop; | |
0e5eabac | 62 | |
68b7c895 HX |
63 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
64 | ||
e081e1e3 HX |
65 | /* The packet skb2 goes to the local host (NULL to skip). */ |
66 | skb2 = NULL; | |
1da177e4 | 67 | |
e081e1e3 HX |
68 | if (br->dev->flags & IFF_PROMISC) |
69 | skb2 = skb; | |
70 | ||
71 | dst = NULL; | |
1da177e4 | 72 | |
dbbc0988 | 73 | if (is_multicast_ether_addr(dest)) { |
c4fcb78c | 74 | mdst = br_mdb_get(br, skb); |
32dec5dd | 75 | if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
c4fcb78c HX |
76 | if ((mdst && !hlist_unhashed(&mdst->mglist)) || |
77 | br_multicast_is_router(br)) | |
78 | skb2 = skb; | |
79 | br_multicast_forward(mdst, skb, skb2); | |
80 | skb = NULL; | |
81 | if (!skb2) | |
82 | goto out; | |
83 | } else | |
84 | skb2 = skb; | |
85 | ||
a339f1c8 | 86 | br->dev->stats.multicast++; |
e081e1e3 HX |
87 | } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
88 | skb2 = skb; | |
89 | /* Do not forward the packet since it's local. */ | |
90 | skb = NULL; | |
1da177e4 LT |
91 | } |
92 | ||
e081e1e3 HX |
93 | if (skb) { |
94 | if (dst) | |
7f7708f0 | 95 | br_forward(dst->dst, skb, skb2); |
e081e1e3 | 96 | else |
b33084be | 97 | br_flood_forward(br, skb, skb2); |
e081e1e3 | 98 | } |
1da177e4 | 99 | |
87557c18 | 100 | if (skb2) |
68b7c895 | 101 | return br_pass_frame_up(skb2); |
87557c18 | 102 | |
1da177e4 LT |
103 | out: |
104 | return 0; | |
b3f1be4b SH |
105 | drop: |
106 | kfree_skb(skb); | |
107 | goto out; | |
1da177e4 LT |
108 | } |
109 | ||
cf0f02d0 SH |
110 | /* note: already called with rcu_read_lock (preempt_disabled) */ |
111 | static int br_handle_local_finish(struct sk_buff *skb) | |
112 | { | |
113 | struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); | |
114 | ||
df1c0b84 | 115 | if (p) |
cf0f02d0 | 116 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
cf0f02d0 SH |
117 | return 0; /* process further */ |
118 | } | |
119 | ||
120 | /* Does address match the link local multicast address. | |
121 | * 01:80:c2:00:00:0X | |
122 | */ | |
b3e83d6d | 123 | static inline int is_link_local(const unsigned char *dest) |
cf0f02d0 | 124 | { |
582ee43d AV |
125 | __be16 *a = (__be16 *)dest; |
126 | static const __be16 *b = (const __be16 *)br_group_address; | |
91c5ec3e | 127 | static const __be16 m = cpu_to_be16(0xfff0); |
fd74e6cc SH |
128 | |
129 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; | |
cf0f02d0 SH |
130 | } |
131 | ||
1da177e4 LT |
132 | /* |
133 | * Called via br_handle_frame_hook. | |
6229e362 | 134 | * Return NULL if skb is handled |
9d6f229f | 135 | * note: already called with rcu_read_lock (preempt_disabled) |
1da177e4 | 136 | */ |
6229e362 | 137 | struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb) |
1da177e4 | 138 | { |
1da177e4 | 139 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
82de382c | 140 | int (*rhook)(struct sk_buff *skb); |
1da177e4 | 141 | |
1da177e4 | 142 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 143 | goto drop; |
1da177e4 | 144 | |
7b995651 HX |
145 | skb = skb_share_check(skb, GFP_ATOMIC); |
146 | if (!skb) | |
147 | return NULL; | |
148 | ||
2111f8b9 SH |
149 | if (unlikely(is_link_local(dest))) { |
150 | /* Pause frames shouldn't be passed up by driver anyway */ | |
151 | if (skb->protocol == htons(ETH_P_PAUSE)) | |
152 | goto drop; | |
153 | ||
a598f6ae SH |
154 | /* If STP is turned off, then forward */ |
155 | if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0) | |
156 | goto forward; | |
157 | ||
43aa1920 SH |
158 | if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
159 | NULL, br_handle_local_finish)) | |
160 | return NULL; /* frame consumed by filter */ | |
161 | else | |
162 | return skb; /* continue processing */ | |
2111f8b9 | 163 | } |
1da177e4 | 164 | |
a598f6ae | 165 | forward: |
467aea0d SH |
166 | switch (p->state) { |
167 | case BR_STATE_FORWARDING: | |
82de382c PE |
168 | rhook = rcu_dereference(br_should_route_hook); |
169 | if (rhook != NULL) { | |
170 | if (rhook(skb)) | |
6229e362 | 171 | return skb; |
1da177e4 LT |
172 | dest = eth_hdr(skb)->h_dest; |
173 | } | |
467aea0d SH |
174 | /* fall through */ |
175 | case BR_STATE_LEARNING: | |
6ede2463 | 176 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
177 | skb->pkt_type = PACKET_HOST; |
178 | ||
179 | NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, | |
180 | br_handle_frame_finish); | |
467aea0d SH |
181 | break; |
182 | default: | |
183 | drop: | |
184 | kfree_skb(skb); | |
1da177e4 | 185 | } |
6229e362 | 186 | return NULL; |
1da177e4 | 187 | } |