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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> | |
bc3b2d7f | 19 | #include <linux/export.h> |
1da177e4 LT |
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 | |
a386f990 ED |
25 | /* Hook for brouter */ |
26 | br_should_route_hook_t __rcu *br_should_route_hook __read_mostly; | |
27 | EXPORT_SYMBOL(br_should_route_hook); | |
28 | ||
68b7c895 | 29 | static int br_pass_frame_up(struct sk_buff *skb) |
1da177e4 | 30 | { |
68b7c895 | 31 | struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; |
14bb4789 | 32 | struct net_bridge *br = netdev_priv(brdev); |
33 | struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats); | |
1da177e4 | 34 | |
406818ff | 35 | u64_stats_update_begin(&brstats->syncp); |
14bb4789 | 36 | brstats->rx_packets++; |
37 | brstats->rx_bytes += skb->len; | |
406818ff | 38 | u64_stats_update_end(&brstats->syncp); |
1da177e4 LT |
39 | |
40 | indev = skb->dev; | |
a339f1c8 | 41 | skb->dev = brdev; |
1da177e4 | 42 | |
713aefa3 | 43 | return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
68b7c895 | 44 | netif_receive_skb); |
1da177e4 LT |
45 | } |
46 | ||
eeaf61d8 | 47 | /* note: already called with rcu_read_lock */ |
1da177e4 LT |
48 | int br_handle_frame_finish(struct sk_buff *skb) |
49 | { | |
50 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
f350a0a8 | 51 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
b3f1be4b | 52 | struct net_bridge *br; |
1da177e4 | 53 | struct net_bridge_fdb_entry *dst; |
c4fcb78c | 54 | struct net_bridge_mdb_entry *mdst; |
e081e1e3 | 55 | struct sk_buff *skb2; |
1da177e4 | 56 | |
b3f1be4b SH |
57 | if (!p || p->state == BR_STATE_DISABLED) |
58 | goto drop; | |
59 | ||
85967bb4 | 60 | /* insert into forwarding database after filtering to avoid spoofing */ |
b3f1be4b SH |
61 | br = p->br; |
62 | br_fdb_update(br, p, eth_hdr(skb)->h_source); | |
85967bb4 | 63 | |
44661462 | 64 | if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) && |
c4fcb78c HX |
65 | br_multicast_rcv(br, p, skb)) |
66 | goto drop; | |
67 | ||
b3f1be4b SH |
68 | if (p->state == BR_STATE_LEARNING) |
69 | goto drop; | |
0e5eabac | 70 | |
68b7c895 HX |
71 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
72 | ||
e081e1e3 HX |
73 | /* The packet skb2 goes to the local host (NULL to skip). */ |
74 | skb2 = NULL; | |
1da177e4 | 75 | |
e081e1e3 HX |
76 | if (br->dev->flags & IFF_PROMISC) |
77 | skb2 = skb; | |
78 | ||
79 | dst = NULL; | |
1da177e4 | 80 | |
44661462 HX |
81 | if (is_broadcast_ether_addr(dest)) |
82 | skb2 = skb; | |
83 | else if (is_multicast_ether_addr(dest)) { | |
c4fcb78c | 84 | mdst = br_mdb_get(br, skb); |
32dec5dd | 85 | if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
8a870178 | 86 | if ((mdst && mdst->mglist) || |
c4fcb78c HX |
87 | br_multicast_is_router(br)) |
88 | skb2 = skb; | |
89 | br_multicast_forward(mdst, skb, skb2); | |
90 | skb = NULL; | |
91 | if (!skb2) | |
92 | goto out; | |
93 | } else | |
94 | skb2 = skb; | |
95 | ||
a339f1c8 | 96 | br->dev->stats.multicast++; |
e081e1e3 HX |
97 | } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
98 | skb2 = skb; | |
99 | /* Do not forward the packet since it's local. */ | |
100 | skb = NULL; | |
1da177e4 LT |
101 | } |
102 | ||
e081e1e3 | 103 | if (skb) { |
7cd8861a | 104 | if (dst) { |
105 | dst->used = jiffies; | |
7f7708f0 | 106 | br_forward(dst->dst, skb, skb2); |
7cd8861a | 107 | } else |
b33084be | 108 | br_flood_forward(br, skb, skb2); |
e081e1e3 | 109 | } |
1da177e4 | 110 | |
87557c18 | 111 | if (skb2) |
68b7c895 | 112 | return br_pass_frame_up(skb2); |
87557c18 | 113 | |
1da177e4 LT |
114 | out: |
115 | return 0; | |
b3f1be4b SH |
116 | drop: |
117 | kfree_skb(skb); | |
118 | goto out; | |
1da177e4 LT |
119 | } |
120 | ||
eeaf61d8 | 121 | /* note: already called with rcu_read_lock */ |
cf0f02d0 SH |
122 | static int br_handle_local_finish(struct sk_buff *skb) |
123 | { | |
f350a0a8 | 124 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
cf0f02d0 | 125 | |
f350a0a8 | 126 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
cf0f02d0 SH |
127 | return 0; /* process further */ |
128 | } | |
129 | ||
130 | /* Does address match the link local multicast address. | |
131 | * 01:80:c2:00:00:0X | |
132 | */ | |
b3e83d6d | 133 | static inline int is_link_local(const unsigned char *dest) |
cf0f02d0 | 134 | { |
582ee43d AV |
135 | __be16 *a = (__be16 *)dest; |
136 | static const __be16 *b = (const __be16 *)br_group_address; | |
91c5ec3e | 137 | static const __be16 m = cpu_to_be16(0xfff0); |
fd74e6cc SH |
138 | |
139 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; | |
cf0f02d0 SH |
140 | } |
141 | ||
1da177e4 | 142 | /* |
6229e362 | 143 | * Return NULL if skb is handled |
eeaf61d8 | 144 | * note: already called with rcu_read_lock |
1da177e4 | 145 | */ |
8a4eb573 | 146 | rx_handler_result_t br_handle_frame(struct sk_buff **pskb) |
1da177e4 | 147 | { |
ab95bfe0 | 148 | struct net_bridge_port *p; |
8a4eb573 | 149 | struct sk_buff *skb = *pskb; |
1da177e4 | 150 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
a386f990 | 151 | br_should_route_hook_t *rhook; |
1da177e4 | 152 | |
c2368e79 | 153 | if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) |
8a4eb573 | 154 | return RX_HANDLER_PASS; |
ab95bfe0 | 155 | |
1da177e4 | 156 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 157 | goto drop; |
1da177e4 | 158 | |
7b995651 HX |
159 | skb = skb_share_check(skb, GFP_ATOMIC); |
160 | if (!skb) | |
8a4eb573 | 161 | return RX_HANDLER_CONSUMED; |
7b995651 | 162 | |
f350a0a8 | 163 | p = br_port_get_rcu(skb->dev); |
ab95bfe0 | 164 | |
2111f8b9 | 165 | if (unlikely(is_link_local(dest))) { |
515853cc | 166 | /* |
167 | * See IEEE 802.1D Table 7-10 Reserved addresses | |
168 | * | |
169 | * Assignment Value | |
170 | * Bridge Group Address 01-80-C2-00-00-00 | |
171 | * (MAC Control) 802.3 01-80-C2-00-00-01 | |
172 | * (Link Aggregation) 802.3 01-80-C2-00-00-02 | |
173 | * 802.1X PAE address 01-80-C2-00-00-03 | |
174 | * | |
175 | * 802.1AB LLDP 01-80-C2-00-00-0E | |
176 | * | |
177 | * Others reserved for future standardization | |
178 | */ | |
179 | switch (dest[5]) { | |
180 | case 0x00: /* Bridge Group Address */ | |
181 | /* If STP is turned off, | |
182 | then must forward to keep loop detection */ | |
183 | if (p->br->stp_enabled == BR_NO_STP) | |
184 | goto forward; | |
185 | break; | |
186 | ||
187 | case 0x01: /* IEEE MAC (Pause) */ | |
2111f8b9 SH |
188 | goto drop; |
189 | ||
515853cc | 190 | default: |
191 | /* Allow selective forwarding for most other protocols */ | |
192 | if (p->br->group_fwd_mask & (1u << dest[5])) | |
193 | goto forward; | |
194 | } | |
a598f6ae | 195 | |
515853cc | 196 | /* Deliver packet to local host only */ |
713aefa3 | 197 | if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
8a4eb573 JP |
198 | NULL, br_handle_local_finish)) { |
199 | return RX_HANDLER_CONSUMED; /* consumed by filter */ | |
200 | } else { | |
201 | *pskb = skb; | |
202 | return RX_HANDLER_PASS; /* continue processing */ | |
203 | } | |
2111f8b9 | 204 | } |
1da177e4 | 205 | |
a598f6ae | 206 | forward: |
467aea0d SH |
207 | switch (p->state) { |
208 | case BR_STATE_FORWARDING: | |
82de382c | 209 | rhook = rcu_dereference(br_should_route_hook); |
a386f990 | 210 | if (rhook) { |
8a4eb573 JP |
211 | if ((*rhook)(skb)) { |
212 | *pskb = skb; | |
213 | return RX_HANDLER_PASS; | |
214 | } | |
1da177e4 LT |
215 | dest = eth_hdr(skb)->h_dest; |
216 | } | |
467aea0d SH |
217 | /* fall through */ |
218 | case BR_STATE_LEARNING: | |
6ede2463 | 219 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
220 | skb->pkt_type = PACKET_HOST; |
221 | ||
713aefa3 | 222 | NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 | 223 | br_handle_frame_finish); |
467aea0d SH |
224 | break; |
225 | default: | |
226 | drop: | |
227 | kfree_skb(skb); | |
1da177e4 | 228 | } |
8a4eb573 | 229 | return RX_HANDLER_CONSUMED; |
1da177e4 | 230 | } |