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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> | |
95850116 KP |
19 | #include <linux/neighbour.h> |
20 | #include <net/arp.h> | |
bc3b2d7f | 21 | #include <linux/export.h> |
a37b85c9 | 22 | #include <linux/rculist.h> |
1da177e4 LT |
23 | #include "br_private.h" |
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); |
8f84985f | 33 | struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats); |
fc92f745 | 34 | struct net_port_vlans *pv; |
1da177e4 | 35 | |
406818ff | 36 | u64_stats_update_begin(&brstats->syncp); |
14bb4789 | 37 | brstats->rx_packets++; |
38 | brstats->rx_bytes += skb->len; | |
406818ff | 39 | u64_stats_update_end(&brstats->syncp); |
1da177e4 | 40 | |
85f46c6b VY |
41 | /* Bridge is just like any other port. Make sure the |
42 | * packet is allowed except in promisc modue when someone | |
43 | * may be running packet capture. | |
44 | */ | |
fc92f745 | 45 | pv = br_get_vlan_info(br); |
85f46c6b | 46 | if (!(brdev->flags & IFF_PROMISC) && |
fc92f745 | 47 | !br_allowed_egress(br, pv, skb)) { |
85f46c6b VY |
48 | kfree_skb(skb); |
49 | return NET_RX_DROP; | |
50 | } | |
51 | ||
1da177e4 | 52 | indev = skb->dev; |
a339f1c8 | 53 | skb->dev = brdev; |
fc92f745 VY |
54 | skb = br_handle_vlan(br, pv, skb); |
55 | if (!skb) | |
56 | return NET_RX_DROP; | |
1da177e4 | 57 | |
713aefa3 | 58 | return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
68b7c895 | 59 | netif_receive_skb); |
1da177e4 LT |
60 | } |
61 | ||
95850116 KP |
62 | static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br, |
63 | u16 vid) | |
64 | { | |
65 | struct net_device *dev = br->dev; | |
66 | struct neighbour *n; | |
67 | struct arphdr *parp; | |
68 | u8 *arpptr, *sha; | |
69 | __be32 sip, tip; | |
70 | ||
71 | if (dev->flags & IFF_NOARP) | |
72 | return; | |
73 | ||
74 | if (!pskb_may_pull(skb, arp_hdr_len(dev))) { | |
75 | dev->stats.tx_dropped++; | |
76 | return; | |
77 | } | |
78 | parp = arp_hdr(skb); | |
79 | ||
80 | if (parp->ar_pro != htons(ETH_P_IP) || | |
81 | parp->ar_op != htons(ARPOP_REQUEST) || | |
82 | parp->ar_hln != dev->addr_len || | |
83 | parp->ar_pln != 4) | |
84 | return; | |
85 | ||
86 | arpptr = (u8 *)parp + sizeof(struct arphdr); | |
87 | sha = arpptr; | |
88 | arpptr += dev->addr_len; /* sha */ | |
89 | memcpy(&sip, arpptr, sizeof(sip)); | |
90 | arpptr += sizeof(sip); | |
91 | arpptr += dev->addr_len; /* tha */ | |
92 | memcpy(&tip, arpptr, sizeof(tip)); | |
93 | ||
94 | if (ipv4_is_loopback(tip) || | |
95 | ipv4_is_multicast(tip)) | |
96 | return; | |
97 | ||
98 | n = neigh_lookup(&arp_tbl, &tip, dev); | |
99 | if (n) { | |
100 | struct net_bridge_fdb_entry *f; | |
101 | ||
102 | if (!(n->nud_state & NUD_VALID)) { | |
103 | neigh_release(n); | |
104 | return; | |
105 | } | |
106 | ||
107 | f = __br_fdb_get(br, n->ha, vid); | |
108 | if (f) | |
109 | arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip, | |
110 | sha, n->ha, sha); | |
111 | ||
112 | neigh_release(n); | |
113 | } | |
114 | } | |
115 | ||
eeaf61d8 | 116 | /* note: already called with rcu_read_lock */ |
1da177e4 LT |
117 | int br_handle_frame_finish(struct sk_buff *skb) |
118 | { | |
119 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
f350a0a8 | 120 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
b3f1be4b | 121 | struct net_bridge *br; |
1da177e4 | 122 | struct net_bridge_fdb_entry *dst; |
c4fcb78c | 123 | struct net_bridge_mdb_entry *mdst; |
e081e1e3 | 124 | struct sk_buff *skb2; |
867a5943 | 125 | bool unicast = true; |
78851988 | 126 | u16 vid = 0; |
1da177e4 | 127 | |
b3f1be4b SH |
128 | if (!p || p->state == BR_STATE_DISABLED) |
129 | goto drop; | |
130 | ||
78851988 | 131 | if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid)) |
eb707618 | 132 | goto out; |
a37b85c9 | 133 | |
85967bb4 | 134 | /* insert into forwarding database after filtering to avoid spoofing */ |
b3f1be4b | 135 | br = p->br; |
9ba18891 | 136 | if (p->flags & BR_LEARNING) |
a5642ab4 | 137 | br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false); |
85967bb4 | 138 | |
44661462 | 139 | if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) && |
06499098 | 140 | br_multicast_rcv(br, p, skb, vid)) |
c4fcb78c HX |
141 | goto drop; |
142 | ||
b3f1be4b SH |
143 | if (p->state == BR_STATE_LEARNING) |
144 | goto drop; | |
0e5eabac | 145 | |
68b7c895 HX |
146 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
147 | ||
e081e1e3 HX |
148 | /* The packet skb2 goes to the local host (NULL to skip). */ |
149 | skb2 = NULL; | |
1da177e4 | 150 | |
e081e1e3 HX |
151 | if (br->dev->flags & IFF_PROMISC) |
152 | skb2 = skb; | |
153 | ||
154 | dst = NULL; | |
1da177e4 | 155 | |
867a5943 | 156 | if (is_broadcast_ether_addr(dest)) { |
d92cfdbb AB |
157 | if (IS_ENABLED(CONFIG_INET) && |
158 | p->flags & BR_PROXYARP && | |
95850116 KP |
159 | skb->protocol == htons(ETH_P_ARP)) |
160 | br_do_proxy_arp(skb, br, vid); | |
161 | ||
44661462 | 162 | skb2 = skb; |
867a5943 VY |
163 | unicast = false; |
164 | } else if (is_multicast_ether_addr(dest)) { | |
fbca58a2 | 165 | mdst = br_mdb_get(br, skb, vid); |
b00589af | 166 | if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) && |
cc0fdd80 | 167 | br_multicast_querier_exists(br, eth_hdr(skb))) { |
8a870178 | 168 | if ((mdst && mdst->mglist) || |
c4fcb78c HX |
169 | br_multicast_is_router(br)) |
170 | skb2 = skb; | |
171 | br_multicast_forward(mdst, skb, skb2); | |
172 | skb = NULL; | |
173 | if (!skb2) | |
174 | goto out; | |
175 | } else | |
176 | skb2 = skb; | |
177 | ||
867a5943 | 178 | unicast = false; |
a339f1c8 | 179 | br->dev->stats.multicast++; |
2ba071ec VY |
180 | } else if ((dst = __br_fdb_get(br, dest, vid)) && |
181 | dst->is_local) { | |
e081e1e3 HX |
182 | skb2 = skb; |
183 | /* Do not forward the packet since it's local. */ | |
184 | skb = NULL; | |
1da177e4 LT |
185 | } |
186 | ||
e081e1e3 | 187 | if (skb) { |
7cd8861a | 188 | if (dst) { |
189 | dst->used = jiffies; | |
7f7708f0 | 190 | br_forward(dst->dst, skb, skb2); |
7cd8861a | 191 | } else |
867a5943 | 192 | br_flood_forward(br, skb, skb2, unicast); |
e081e1e3 | 193 | } |
1da177e4 | 194 | |
87557c18 | 195 | if (skb2) |
68b7c895 | 196 | return br_pass_frame_up(skb2); |
87557c18 | 197 | |
1da177e4 LT |
198 | out: |
199 | return 0; | |
b3f1be4b SH |
200 | drop: |
201 | kfree_skb(skb); | |
202 | goto out; | |
1da177e4 | 203 | } |
34666d46 | 204 | EXPORT_SYMBOL_GPL(br_handle_frame_finish); |
1da177e4 | 205 | |
eeaf61d8 | 206 | /* note: already called with rcu_read_lock */ |
cf0f02d0 SH |
207 | static int br_handle_local_finish(struct sk_buff *skb) |
208 | { | |
f350a0a8 | 209 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
2ba071ec | 210 | u16 vid = 0; |
cf0f02d0 | 211 | |
e0d7968a TM |
212 | /* check if vlan is allowed, to avoid spoofing */ |
213 | if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid)) | |
a5642ab4 | 214 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false); |
cf0f02d0 SH |
215 | return 0; /* process further */ |
216 | } | |
217 | ||
1da177e4 | 218 | /* |
6229e362 | 219 | * Return NULL if skb is handled |
eeaf61d8 | 220 | * note: already called with rcu_read_lock |
1da177e4 | 221 | */ |
8a4eb573 | 222 | rx_handler_result_t br_handle_frame(struct sk_buff **pskb) |
1da177e4 | 223 | { |
ab95bfe0 | 224 | struct net_bridge_port *p; |
8a4eb573 | 225 | struct sk_buff *skb = *pskb; |
1da177e4 | 226 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
a386f990 | 227 | br_should_route_hook_t *rhook; |
1da177e4 | 228 | |
c2368e79 | 229 | if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) |
8a4eb573 | 230 | return RX_HANDLER_PASS; |
ab95bfe0 | 231 | |
1da177e4 | 232 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
467aea0d | 233 | goto drop; |
1da177e4 | 234 | |
7b995651 HX |
235 | skb = skb_share_check(skb, GFP_ATOMIC); |
236 | if (!skb) | |
8a4eb573 | 237 | return RX_HANDLER_CONSUMED; |
7b995651 | 238 | |
f350a0a8 | 239 | p = br_port_get_rcu(skb->dev); |
ab95bfe0 | 240 | |
46acc460 | 241 | if (unlikely(is_link_local_ether_addr(dest))) { |
f2808d22 TM |
242 | u16 fwd_mask = p->br->group_fwd_mask_required; |
243 | ||
515853cc | 244 | /* |
245 | * See IEEE 802.1D Table 7-10 Reserved addresses | |
246 | * | |
247 | * Assignment Value | |
248 | * Bridge Group Address 01-80-C2-00-00-00 | |
249 | * (MAC Control) 802.3 01-80-C2-00-00-01 | |
250 | * (Link Aggregation) 802.3 01-80-C2-00-00-02 | |
251 | * 802.1X PAE address 01-80-C2-00-00-03 | |
252 | * | |
253 | * 802.1AB LLDP 01-80-C2-00-00-0E | |
254 | * | |
255 | * Others reserved for future standardization | |
256 | */ | |
257 | switch (dest[5]) { | |
258 | case 0x00: /* Bridge Group Address */ | |
259 | /* If STP is turned off, | |
260 | then must forward to keep loop detection */ | |
f2808d22 TM |
261 | if (p->br->stp_enabled == BR_NO_STP || |
262 | fwd_mask & (1u << dest[5])) | |
515853cc | 263 | goto forward; |
264 | break; | |
265 | ||
266 | case 0x01: /* IEEE MAC (Pause) */ | |
2111f8b9 SH |
267 | goto drop; |
268 | ||
515853cc | 269 | default: |
270 | /* Allow selective forwarding for most other protocols */ | |
f2808d22 TM |
271 | fwd_mask |= p->br->group_fwd_mask; |
272 | if (fwd_mask & (1u << dest[5])) | |
515853cc | 273 | goto forward; |
274 | } | |
a598f6ae | 275 | |
515853cc | 276 | /* Deliver packet to local host only */ |
713aefa3 | 277 | if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
8a4eb573 JP |
278 | NULL, br_handle_local_finish)) { |
279 | return RX_HANDLER_CONSUMED; /* consumed by filter */ | |
280 | } else { | |
281 | *pskb = skb; | |
282 | return RX_HANDLER_PASS; /* continue processing */ | |
283 | } | |
2111f8b9 | 284 | } |
1da177e4 | 285 | |
a598f6ae | 286 | forward: |
467aea0d SH |
287 | switch (p->state) { |
288 | case BR_STATE_FORWARDING: | |
82de382c | 289 | rhook = rcu_dereference(br_should_route_hook); |
a386f990 | 290 | if (rhook) { |
8a4eb573 JP |
291 | if ((*rhook)(skb)) { |
292 | *pskb = skb; | |
293 | return RX_HANDLER_PASS; | |
294 | } | |
1da177e4 LT |
295 | dest = eth_hdr(skb)->h_dest; |
296 | } | |
467aea0d SH |
297 | /* fall through */ |
298 | case BR_STATE_LEARNING: | |
9a7b6ef9 | 299 | if (ether_addr_equal(p->br->dev->dev_addr, dest)) |
1da177e4 LT |
300 | skb->pkt_type = PACKET_HOST; |
301 | ||
713aefa3 | 302 | NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 | 303 | br_handle_frame_finish); |
467aea0d SH |
304 | break; |
305 | default: | |
306 | drop: | |
307 | kfree_skb(skb); | |
1da177e4 | 308 | } |
8a4eb573 | 309 | return RX_HANDLER_CONSUMED; |
1da177e4 | 310 | } |