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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Handle firewalling | |
3 | * Linux ethernet bridge | |
4 | * | |
5 | * Authors: | |
8237908e BDS |
6 | * Lennert Buytenhek <buytenh@gnu.org> |
7 | * Bart De Schuymer <bdschuym@pandora.be> | |
1da177e4 LT |
8 | * |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | * | |
14 | * Lennert dedicates this file to Kerstin Wurdinger. | |
15 | */ | |
16 | ||
17 | #include <linux/module.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/ip.h> | |
20 | #include <linux/netdevice.h> | |
21 | #include <linux/skbuff.h> | |
14c85021 | 22 | #include <linux/if_arp.h> |
1da177e4 LT |
23 | #include <linux/if_ether.h> |
24 | #include <linux/if_vlan.h> | |
516299d2 MM |
25 | #include <linux/if_pppox.h> |
26 | #include <linux/ppp_defs.h> | |
1da177e4 LT |
27 | #include <linux/netfilter_bridge.h> |
28 | #include <linux/netfilter_ipv4.h> | |
29 | #include <linux/netfilter_ipv6.h> | |
30 | #include <linux/netfilter_arp.h> | |
31 | #include <linux/in_route.h> | |
f216f082 | 32 | #include <linux/inetdevice.h> |
14c85021 | 33 | |
1da177e4 LT |
34 | #include <net/ip.h> |
35 | #include <net/ipv6.h> | |
14c85021 ACM |
36 | #include <net/route.h> |
37 | ||
1da177e4 | 38 | #include <asm/uaccess.h> |
1da177e4 LT |
39 | #include "br_private.h" |
40 | #ifdef CONFIG_SYSCTL | |
41 | #include <linux/sysctl.h> | |
42 | #endif | |
43 | ||
44 | #define skb_origaddr(skb) (((struct bridge_skb_cb *) \ | |
45 | (skb->nf_bridge->data))->daddr.ipv4) | |
eddc9ec5 ACM |
46 | #define store_orig_dstaddr(skb) (skb_origaddr(skb) = ip_hdr(skb)->daddr) |
47 | #define dnat_took_place(skb) (skb_origaddr(skb) != ip_hdr(skb)->daddr) | |
1da177e4 | 48 | |
1da177e4 LT |
49 | #ifdef CONFIG_SYSCTL |
50 | static struct ctl_table_header *brnf_sysctl_header; | |
9c1ea148 BH |
51 | static int brnf_call_iptables __read_mostly = 1; |
52 | static int brnf_call_ip6tables __read_mostly = 1; | |
53 | static int brnf_call_arptables __read_mostly = 1; | |
47e0e1ca HX |
54 | static int brnf_filter_vlan_tagged __read_mostly = 0; |
55 | static int brnf_filter_pppoe_tagged __read_mostly = 0; | |
1da177e4 | 56 | #else |
47e0e1ca HX |
57 | #define brnf_filter_vlan_tagged 0 |
58 | #define brnf_filter_pppoe_tagged 0 | |
1da177e4 LT |
59 | #endif |
60 | ||
b6f99a21 | 61 | static inline __be16 vlan_proto(const struct sk_buff *skb) |
8b42ec39 SH |
62 | { |
63 | return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto; | |
64 | } | |
65 | ||
66 | #define IS_VLAN_IP(skb) \ | |
67 | (skb->protocol == htons(ETH_P_8021Q) && \ | |
9d6f229f | 68 | vlan_proto(skb) == htons(ETH_P_IP) && \ |
8b42ec39 SH |
69 | brnf_filter_vlan_tagged) |
70 | ||
71 | #define IS_VLAN_IPV6(skb) \ | |
72 | (skb->protocol == htons(ETH_P_8021Q) && \ | |
73 | vlan_proto(skb) == htons(ETH_P_IPV6) &&\ | |
74 | brnf_filter_vlan_tagged) | |
75 | ||
76 | #define IS_VLAN_ARP(skb) \ | |
77 | (skb->protocol == htons(ETH_P_8021Q) && \ | |
78 | vlan_proto(skb) == htons(ETH_P_ARP) && \ | |
79 | brnf_filter_vlan_tagged) | |
1da177e4 | 80 | |
516299d2 MM |
81 | static inline __be16 pppoe_proto(const struct sk_buff *skb) |
82 | { | |
83 | return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN + | |
84 | sizeof(struct pppoe_hdr))); | |
85 | } | |
86 | ||
87 | #define IS_PPPOE_IP(skb) \ | |
88 | (skb->protocol == htons(ETH_P_PPP_SES) && \ | |
89 | pppoe_proto(skb) == htons(PPP_IP) && \ | |
90 | brnf_filter_pppoe_tagged) | |
91 | ||
92 | #define IS_PPPOE_IPV6(skb) \ | |
93 | (skb->protocol == htons(ETH_P_PPP_SES) && \ | |
94 | pppoe_proto(skb) == htons(PPP_IPV6) && \ | |
95 | brnf_filter_pppoe_tagged) | |
96 | ||
631339f1 HX |
97 | static void fake_update_pmtu(struct dst_entry *dst, u32 mtu) |
98 | { | |
99 | } | |
100 | ||
101 | static struct dst_ops fake_dst_ops = { | |
102 | .family = AF_INET, | |
09640e63 | 103 | .protocol = cpu_to_be16(ETH_P_IP), |
631339f1 | 104 | .update_pmtu = fake_update_pmtu, |
631339f1 HX |
105 | .entries = ATOMIC_INIT(0), |
106 | }; | |
107 | ||
4adf0af6 SW |
108 | /* |
109 | * Initialize bogus route table used to keep netfilter happy. | |
1da177e4 LT |
110 | * Currently, we fill in the PMTU entry because netfilter |
111 | * refragmentation needs it, and the rt_flags entry because | |
112 | * ipt_REJECT needs it. Future netfilter modules might | |
4adf0af6 SW |
113 | * require us to fill additional fields. |
114 | */ | |
115 | void br_netfilter_rtable_init(struct net_bridge *br) | |
116 | { | |
117 | struct rtable *rt = &br->fake_rtable; | |
118 | ||
119 | atomic_set(&rt->u.dst.__refcnt, 1); | |
ad619800 | 120 | rt->u.dst.dev = br->dev; |
4adf0af6 SW |
121 | rt->u.dst.path = &rt->u.dst; |
122 | rt->u.dst.metrics[RTAX_MTU - 1] = 1500; | |
123 | rt->u.dst.flags = DST_NOXFRM; | |
631339f1 | 124 | rt->u.dst.ops = &fake_dst_ops; |
4adf0af6 SW |
125 | } |
126 | ||
127 | static inline struct rtable *bridge_parent_rtable(const struct net_device *dev) | |
128 | { | |
129 | struct net_bridge_port *port = rcu_dereference(dev->br_port); | |
130 | ||
131 | return port ? &port->br->fake_rtable : NULL; | |
132 | } | |
1da177e4 | 133 | |
5dce971a SH |
134 | static inline struct net_device *bridge_parent(const struct net_device *dev) |
135 | { | |
136 | struct net_bridge_port *port = rcu_dereference(dev->br_port); | |
137 | ||
138 | return port ? port->br->dev : NULL; | |
139 | } | |
1da177e4 | 140 | |
fdeabdef SH |
141 | static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb) |
142 | { | |
143 | skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC); | |
144 | if (likely(skb->nf_bridge)) | |
145 | atomic_set(&(skb->nf_bridge->use), 1); | |
146 | ||
147 | return skb->nf_bridge; | |
148 | } | |
149 | ||
2dc2f207 PM |
150 | static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb) |
151 | { | |
152 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; | |
153 | ||
154 | if (atomic_read(&nf_bridge->use) > 1) { | |
155 | struct nf_bridge_info *tmp = nf_bridge_alloc(skb); | |
156 | ||
157 | if (tmp) { | |
158 | memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info)); | |
159 | atomic_set(&tmp->use, 1); | |
160 | nf_bridge_put(nf_bridge); | |
161 | } | |
162 | nf_bridge = tmp; | |
163 | } | |
164 | return nf_bridge; | |
165 | } | |
166 | ||
fc38582d PM |
167 | static inline void nf_bridge_push_encap_header(struct sk_buff *skb) |
168 | { | |
169 | unsigned int len = nf_bridge_encap_header_len(skb); | |
170 | ||
171 | skb_push(skb, len); | |
172 | skb->network_header -= len; | |
173 | } | |
174 | ||
175 | static inline void nf_bridge_pull_encap_header(struct sk_buff *skb) | |
fdeabdef | 176 | { |
fc38582d PM |
177 | unsigned int len = nf_bridge_encap_header_len(skb); |
178 | ||
179 | skb_pull(skb, len); | |
180 | skb->network_header += len; | |
181 | } | |
fdeabdef | 182 | |
fc38582d PM |
183 | static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb) |
184 | { | |
185 | unsigned int len = nf_bridge_encap_header_len(skb); | |
186 | ||
187 | skb_pull_rcsum(skb, len); | |
188 | skb->network_header += len; | |
189 | } | |
190 | ||
191 | static inline void nf_bridge_save_header(struct sk_buff *skb) | |
192 | { | |
193 | int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb); | |
fdeabdef | 194 | |
d626f62b ACM |
195 | skb_copy_from_linear_data_offset(skb, -header_size, |
196 | skb->nf_bridge->data, header_size); | |
fdeabdef SH |
197 | } |
198 | ||
07317621 SH |
199 | /* |
200 | * When forwarding bridge frames, we save a copy of the original | |
201 | * header before processing. | |
202 | */ | |
203 | int nf_bridge_copy_header(struct sk_buff *skb) | |
204 | { | |
205 | int err; | |
fc38582d | 206 | int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb); |
07317621 | 207 | |
d9cc2048 | 208 | err = skb_cow_head(skb, header_size); |
07317621 SH |
209 | if (err) |
210 | return err; | |
211 | ||
27d7ff46 ACM |
212 | skb_copy_to_linear_data_offset(skb, -header_size, |
213 | skb->nf_bridge->data, header_size); | |
fc38582d | 214 | __skb_push(skb, nf_bridge_encap_header_len(skb)); |
07317621 SH |
215 | return 0; |
216 | } | |
217 | ||
1da177e4 LT |
218 | /* PF_BRIDGE/PRE_ROUTING *********************************************/ |
219 | /* Undo the changes made for ip6tables PREROUTING and continue the | |
220 | * bridge PRE_ROUTING hook. */ | |
221 | static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb) | |
222 | { | |
223 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; | |
511c3f92 | 224 | struct rtable *rt; |
1da177e4 | 225 | |
1da177e4 LT |
226 | if (nf_bridge->mask & BRNF_PKT_TYPE) { |
227 | skb->pkt_type = PACKET_OTHERHOST; | |
228 | nf_bridge->mask ^= BRNF_PKT_TYPE; | |
229 | } | |
230 | nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; | |
231 | ||
511c3f92 ED |
232 | rt = bridge_parent_rtable(nf_bridge->physindev); |
233 | if (!rt) { | |
4adf0af6 SW |
234 | kfree_skb(skb); |
235 | return 0; | |
236 | } | |
511c3f92 | 237 | dst_hold(&rt->u.dst); |
adf30907 | 238 | skb_dst_set(skb, &rt->u.dst); |
1da177e4 LT |
239 | |
240 | skb->dev = nf_bridge->physindev; | |
fc38582d | 241 | nf_bridge_push_encap_header(skb); |
713aefa3 | 242 | NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 LT |
243 | br_handle_frame_finish, 1); |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
1da177e4 | 248 | /* This requires some explaining. If DNAT has taken place, |
ea2d9b41 | 249 | * we will need to fix up the destination Ethernet address. |
1da177e4 LT |
250 | * |
251 | * There are two cases to consider: | |
252 | * 1. The packet was DNAT'ed to a device in the same bridge | |
253 | * port group as it was received on. We can still bridge | |
254 | * the packet. | |
255 | * 2. The packet was DNAT'ed to a different device, either | |
256 | * a non-bridged device or another bridge port group. | |
257 | * The packet will need to be routed. | |
258 | * | |
259 | * The correct way of distinguishing between these two cases is to | |
260 | * call ip_route_input() and to look at skb->dst->dev, which is | |
261 | * changed to the destination device if ip_route_input() succeeds. | |
262 | * | |
ea2d9b41 | 263 | * Let's first consider the case that ip_route_input() succeeds: |
1da177e4 | 264 | * |
ea2d9b41 BDS |
265 | * If the output device equals the logical bridge device the packet |
266 | * came in on, we can consider this bridging. The corresponding MAC | |
267 | * address will be obtained in br_nf_pre_routing_finish_bridge. | |
1da177e4 LT |
268 | * Otherwise, the packet is considered to be routed and we just |
269 | * change the destination MAC address so that the packet will | |
f216f082 BDS |
270 | * later be passed up to the IP stack to be routed. For a redirected |
271 | * packet, ip_route_input() will give back the localhost as output device, | |
272 | * which differs from the bridge device. | |
1da177e4 | 273 | * |
ea2d9b41 | 274 | * Let's now consider the case that ip_route_input() fails: |
1da177e4 | 275 | * |
f216f082 BDS |
276 | * This can be because the destination address is martian, in which case |
277 | * the packet will be dropped. | |
ea2d9b41 BDS |
278 | * If IP forwarding is disabled, ip_route_input() will fail, while |
279 | * ip_route_output_key() can return success. The source | |
280 | * address for ip_route_output_key() is set to zero, so ip_route_output_key() | |
1da177e4 | 281 | * thinks we're handling a locally generated packet and won't care |
ea2d9b41 BDS |
282 | * if IP forwarding is enabled. If the output device equals the logical bridge |
283 | * device, we proceed as if ip_route_input() succeeded. If it differs from the | |
284 | * logical bridge port or if ip_route_output_key() fails we drop the packet. | |
285 | */ | |
286 | ||
1da177e4 LT |
287 | static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb) |
288 | { | |
1da177e4 | 289 | skb->dev = bridge_parent(skb->dev); |
2948d2eb | 290 | if (skb->dev) { |
adf30907 | 291 | struct dst_entry *dst = skb_dst(skb); |
2948d2eb | 292 | |
fc38582d | 293 | nf_bridge_pull_encap_header(skb); |
ea2d9b41 | 294 | skb->nf_bridge->mask |= BRNF_BRIDGED_DNAT; |
2948d2eb PM |
295 | |
296 | if (dst->hh) | |
297 | return neigh_hh_output(dst->hh, skb); | |
298 | else if (dst->neighbour) | |
299 | return dst->neighbour->output(skb); | |
1da177e4 | 300 | } |
2948d2eb | 301 | kfree_skb(skb); |
1da177e4 LT |
302 | return 0; |
303 | } | |
304 | ||
305 | static int br_nf_pre_routing_finish(struct sk_buff *skb) | |
306 | { | |
307 | struct net_device *dev = skb->dev; | |
eddc9ec5 | 308 | struct iphdr *iph = ip_hdr(skb); |
1da177e4 | 309 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
511c3f92 | 310 | struct rtable *rt; |
f216f082 | 311 | int err; |
1da177e4 | 312 | |
1da177e4 LT |
313 | if (nf_bridge->mask & BRNF_PKT_TYPE) { |
314 | skb->pkt_type = PACKET_OTHERHOST; | |
315 | nf_bridge->mask ^= BRNF_PKT_TYPE; | |
316 | } | |
317 | nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; | |
1da177e4 | 318 | if (dnat_took_place(skb)) { |
f216f082 | 319 | if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) { |
789bc3e5 SH |
320 | struct flowi fl = { |
321 | .nl_u = { | |
322 | .ip4_u = { | |
323 | .daddr = iph->daddr, | |
324 | .saddr = 0, | |
325 | .tos = RT_TOS(iph->tos) }, | |
326 | }, | |
327 | .proto = 0, | |
328 | }; | |
f3abc9b9 | 329 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
f216f082 BDS |
330 | |
331 | /* If err equals -EHOSTUNREACH the error is due to a | |
332 | * martian destination or due to the fact that | |
333 | * forwarding is disabled. For most martian packets, | |
334 | * ip_route_output_key() will fail. It won't fail for 2 types of | |
335 | * martian destinations: loopback destinations and destination | |
336 | * 0.0.0.0. In both cases the packet will be dropped because the | |
337 | * destination is the loopback device and not the bridge. */ | |
338 | if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev)) | |
339 | goto free_skb; | |
1da177e4 | 340 | |
249b6203 | 341 | if (!ip_route_output_key(dev_net(dev), &rt, &fl)) { |
1c011bed | 342 | /* - Bridged-and-DNAT'ed traffic doesn't |
f216f082 BDS |
343 | * require ip_forwarding. */ |
344 | if (((struct dst_entry *)rt)->dev == dev) { | |
adf30907 | 345 | skb_dst_set(skb, (struct dst_entry *)rt); |
1da177e4 LT |
346 | goto bridged_dnat; |
347 | } | |
1da177e4 LT |
348 | dst_release((struct dst_entry *)rt); |
349 | } | |
f216f082 | 350 | free_skb: |
1da177e4 LT |
351 | kfree_skb(skb); |
352 | return 0; | |
353 | } else { | |
adf30907 | 354 | if (skb_dst(skb)->dev == dev) { |
1da177e4 | 355 | bridged_dnat: |
1da177e4 | 356 | skb->dev = nf_bridge->physindev; |
fc38582d | 357 | nf_bridge_push_encap_header(skb); |
713aefa3 JE |
358 | NF_HOOK_THRESH(NFPROTO_BRIDGE, |
359 | NF_BR_PRE_ROUTING, | |
1da177e4 LT |
360 | skb, skb->dev, NULL, |
361 | br_nf_pre_routing_finish_bridge, | |
362 | 1); | |
363 | return 0; | |
364 | } | |
789bc3e5 | 365 | memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN); |
1da177e4 LT |
366 | skb->pkt_type = PACKET_HOST; |
367 | } | |
368 | } else { | |
511c3f92 ED |
369 | rt = bridge_parent_rtable(nf_bridge->physindev); |
370 | if (!rt) { | |
4adf0af6 SW |
371 | kfree_skb(skb); |
372 | return 0; | |
373 | } | |
511c3f92 | 374 | dst_hold(&rt->u.dst); |
adf30907 | 375 | skb_dst_set(skb, &rt->u.dst); |
1da177e4 LT |
376 | } |
377 | ||
378 | skb->dev = nf_bridge->physindev; | |
fc38582d | 379 | nf_bridge_push_encap_header(skb); |
713aefa3 | 380 | NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 LT |
381 | br_handle_frame_finish, 1); |
382 | ||
383 | return 0; | |
384 | } | |
385 | ||
386 | /* Some common code for IPv4/IPv6 */ | |
5dce971a | 387 | static struct net_device *setup_pre_routing(struct sk_buff *skb) |
1da177e4 LT |
388 | { |
389 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; | |
390 | ||
391 | if (skb->pkt_type == PACKET_OTHERHOST) { | |
392 | skb->pkt_type = PACKET_HOST; | |
393 | nf_bridge->mask |= BRNF_PKT_TYPE; | |
394 | } | |
395 | ||
396 | nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING; | |
397 | nf_bridge->physindev = skb->dev; | |
398 | skb->dev = bridge_parent(skb->dev); | |
5dce971a SH |
399 | |
400 | return skb->dev; | |
1da177e4 LT |
401 | } |
402 | ||
403 | /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */ | |
404 | static int check_hbh_len(struct sk_buff *skb) | |
405 | { | |
0660e03f | 406 | unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1); |
1da177e4 | 407 | u32 pkt_len; |
d56f90a7 ACM |
408 | const unsigned char *nh = skb_network_header(skb); |
409 | int off = raw - nh; | |
789bc3e5 | 410 | int len = (raw[1] + 1) << 3; |
1da177e4 LT |
411 | |
412 | if ((raw + len) - skb->data > skb_headlen(skb)) | |
413 | goto bad; | |
414 | ||
415 | off += 2; | |
416 | len -= 2; | |
417 | ||
418 | while (len > 0) { | |
d56f90a7 | 419 | int optlen = nh[off + 1] + 2; |
1da177e4 | 420 | |
d56f90a7 | 421 | switch (nh[off]) { |
1da177e4 LT |
422 | case IPV6_TLV_PAD0: |
423 | optlen = 1; | |
424 | break; | |
425 | ||
426 | case IPV6_TLV_PADN: | |
427 | break; | |
428 | ||
429 | case IPV6_TLV_JUMBO: | |
d56f90a7 | 430 | if (nh[off + 1] != 4 || (off & 3) != 2) |
1da177e4 | 431 | goto bad; |
d56f90a7 | 432 | pkt_len = ntohl(*(__be32 *) (nh + off + 2)); |
b0366486 | 433 | if (pkt_len <= IPV6_MAXPLEN || |
0660e03f | 434 | ipv6_hdr(skb)->payload_len) |
b0366486 | 435 | goto bad; |
1da177e4 LT |
436 | if (pkt_len > skb->len - sizeof(struct ipv6hdr)) |
437 | goto bad; | |
b0366486 | 438 | if (pskb_trim_rcsum(skb, |
789bc3e5 | 439 | pkt_len + sizeof(struct ipv6hdr))) |
b0366486 | 440 | goto bad; |
d56f90a7 | 441 | nh = skb_network_header(skb); |
1da177e4 LT |
442 | break; |
443 | default: | |
444 | if (optlen > len) | |
445 | goto bad; | |
446 | break; | |
447 | } | |
448 | off += optlen; | |
449 | len -= optlen; | |
450 | } | |
451 | if (len == 0) | |
452 | return 0; | |
453 | bad: | |
454 | return -1; | |
455 | ||
456 | } | |
457 | ||
458 | /* Replicate the checks that IPv6 does on packet reception and pass the packet | |
459 | * to ip6tables, which doesn't support NAT, so things are fairly simple. */ | |
460 | static unsigned int br_nf_pre_routing_ipv6(unsigned int hook, | |
789bc3e5 SH |
461 | struct sk_buff *skb, |
462 | const struct net_device *in, | |
463 | const struct net_device *out, | |
464 | int (*okfn)(struct sk_buff *)) | |
1da177e4 LT |
465 | { |
466 | struct ipv6hdr *hdr; | |
467 | u32 pkt_len; | |
1da177e4 LT |
468 | |
469 | if (skb->len < sizeof(struct ipv6hdr)) | |
470 | goto inhdr_error; | |
471 | ||
472 | if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) | |
473 | goto inhdr_error; | |
474 | ||
0660e03f | 475 | hdr = ipv6_hdr(skb); |
1da177e4 LT |
476 | |
477 | if (hdr->version != 6) | |
478 | goto inhdr_error; | |
479 | ||
480 | pkt_len = ntohs(hdr->payload_len); | |
481 | ||
482 | if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { | |
483 | if (pkt_len + sizeof(struct ipv6hdr) > skb->len) | |
484 | goto inhdr_error; | |
b38dfee3 HX |
485 | if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) |
486 | goto inhdr_error; | |
1da177e4 LT |
487 | } |
488 | if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb)) | |
789bc3e5 | 489 | goto inhdr_error; |
1da177e4 | 490 | |
789bc3e5 | 491 | nf_bridge_put(skb->nf_bridge); |
fdeabdef | 492 | if (!nf_bridge_alloc(skb)) |
1da177e4 | 493 | return NF_DROP; |
5dce971a SH |
494 | if (!setup_pre_routing(skb)) |
495 | return NF_DROP; | |
1da177e4 | 496 | |
713aefa3 | 497 | NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 LT |
498 | br_nf_pre_routing_finish_ipv6); |
499 | ||
500 | return NF_STOLEN; | |
501 | ||
502 | inhdr_error: | |
503 | return NF_DROP; | |
504 | } | |
505 | ||
506 | /* Direct IPv6 traffic to br_nf_pre_routing_ipv6. | |
507 | * Replicate the checks that IPv4 does on packet reception. | |
508 | * Set skb->dev to the bridge device (i.e. parent of the | |
509 | * receiving device) to make netfilter happy, the REDIRECT | |
510 | * target in particular. Save the original destination IP | |
511 | * address to be able to detect DNAT afterwards. */ | |
3db05fea | 512 | static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb, |
ee02b3a6 SH |
513 | const struct net_device *in, |
514 | const struct net_device *out, | |
515 | int (*okfn)(struct sk_buff *)) | |
1da177e4 LT |
516 | { |
517 | struct iphdr *iph; | |
e7c243c9 EP |
518 | __u32 len = nf_bridge_encap_header_len(skb); |
519 | ||
e7c243c9 EP |
520 | if (unlikely(!pskb_may_pull(skb, len))) |
521 | goto out; | |
1da177e4 | 522 | |
516299d2 MM |
523 | if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) || |
524 | IS_PPPOE_IPV6(skb)) { | |
1da177e4 LT |
525 | #ifdef CONFIG_SYSCTL |
526 | if (!brnf_call_ip6tables) | |
527 | return NF_ACCEPT; | |
528 | #endif | |
fc38582d | 529 | nf_bridge_pull_encap_header_rcsum(skb); |
1da177e4 LT |
530 | return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn); |
531 | } | |
532 | #ifdef CONFIG_SYSCTL | |
533 | if (!brnf_call_iptables) | |
534 | return NF_ACCEPT; | |
535 | #endif | |
536 | ||
516299d2 MM |
537 | if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb) && |
538 | !IS_PPPOE_IP(skb)) | |
1da177e4 LT |
539 | return NF_ACCEPT; |
540 | ||
fc38582d | 541 | nf_bridge_pull_encap_header_rcsum(skb); |
1da177e4 LT |
542 | |
543 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) | |
544 | goto inhdr_error; | |
545 | ||
eddc9ec5 | 546 | iph = ip_hdr(skb); |
1da177e4 LT |
547 | if (iph->ihl < 5 || iph->version != 4) |
548 | goto inhdr_error; | |
549 | ||
789bc3e5 | 550 | if (!pskb_may_pull(skb, 4 * iph->ihl)) |
1da177e4 LT |
551 | goto inhdr_error; |
552 | ||
eddc9ec5 | 553 | iph = ip_hdr(skb); |
789bc3e5 | 554 | if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0) |
1da177e4 LT |
555 | goto inhdr_error; |
556 | ||
557 | len = ntohs(iph->tot_len); | |
789bc3e5 | 558 | if (skb->len < len || len < 4 * iph->ihl) |
1da177e4 LT |
559 | goto inhdr_error; |
560 | ||
b38dfee3 | 561 | pskb_trim_rcsum(skb, len); |
1da177e4 | 562 | |
789bc3e5 | 563 | nf_bridge_put(skb->nf_bridge); |
fdeabdef | 564 | if (!nf_bridge_alloc(skb)) |
1da177e4 | 565 | return NF_DROP; |
5dce971a SH |
566 | if (!setup_pre_routing(skb)) |
567 | return NF_DROP; | |
1da177e4 LT |
568 | store_orig_dstaddr(skb); |
569 | ||
713aefa3 | 570 | NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL, |
1da177e4 LT |
571 | br_nf_pre_routing_finish); |
572 | ||
573 | return NF_STOLEN; | |
574 | ||
575 | inhdr_error: | |
789bc3e5 | 576 | // IP_INC_STATS_BH(IpInHdrErrors); |
1da177e4 LT |
577 | out: |
578 | return NF_DROP; | |
579 | } | |
580 | ||
581 | ||
582 | /* PF_BRIDGE/LOCAL_IN ************************************************/ | |
583 | /* The packet is locally destined, which requires a real | |
584 | * dst_entry, so detach the fake one. On the way up, the | |
585 | * packet would pass through PRE_ROUTING again (which already | |
586 | * took place when the packet entered the bridge), but we | |
587 | * register an IPv4 PRE_ROUTING 'sabotage' hook that will | |
588 | * prevent this from happening. */ | |
3db05fea | 589 | static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff *skb, |
789bc3e5 SH |
590 | const struct net_device *in, |
591 | const struct net_device *out, | |
592 | int (*okfn)(struct sk_buff *)) | |
1da177e4 | 593 | { |
511c3f92 ED |
594 | struct rtable *rt = skb_rtable(skb); |
595 | ||
adf30907 ED |
596 | if (rt && rt == bridge_parent_rtable(in)) |
597 | skb_dst_drop(skb); | |
1da177e4 LT |
598 | |
599 | return NF_ACCEPT; | |
600 | } | |
601 | ||
1da177e4 LT |
602 | /* PF_BRIDGE/FORWARD *************************************************/ |
603 | static int br_nf_forward_finish(struct sk_buff *skb) | |
604 | { | |
605 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; | |
606 | struct net_device *in; | |
1da177e4 | 607 | |
8b42ec39 | 608 | if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) { |
1da177e4 LT |
609 | in = nf_bridge->physindev; |
610 | if (nf_bridge->mask & BRNF_PKT_TYPE) { | |
611 | skb->pkt_type = PACKET_OTHERHOST; | |
612 | nf_bridge->mask ^= BRNF_PKT_TYPE; | |
613 | } | |
614 | } else { | |
615 | in = *((struct net_device **)(skb->cb)); | |
616 | } | |
fc38582d | 617 | nf_bridge_push_encap_header(skb); |
713aefa3 | 618 | NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, in, |
789bc3e5 | 619 | skb->dev, br_forward_finish, 1); |
1da177e4 LT |
620 | return 0; |
621 | } | |
622 | ||
623 | /* This is the 'purely bridged' case. For IP, we pass the packet to | |
624 | * netfilter with indev and outdev set to the bridge device, | |
625 | * but we are still able to filter on the 'real' indev/outdev | |
626 | * because of the physdev module. For ARP, indev and outdev are the | |
627 | * bridge ports. */ | |
3db05fea | 628 | static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb, |
789bc3e5 SH |
629 | const struct net_device *in, |
630 | const struct net_device *out, | |
631 | int (*okfn)(struct sk_buff *)) | |
1da177e4 | 632 | { |
1da177e4 | 633 | struct nf_bridge_info *nf_bridge; |
5dce971a | 634 | struct net_device *parent; |
76108cea | 635 | u_int8_t pf; |
1da177e4 LT |
636 | |
637 | if (!skb->nf_bridge) | |
638 | return NF_ACCEPT; | |
639 | ||
2dc2f207 PM |
640 | /* Need exclusive nf_bridge_info since we might have multiple |
641 | * different physoutdevs. */ | |
642 | if (!nf_bridge_unshare(skb)) | |
643 | return NF_DROP; | |
644 | ||
5dce971a SH |
645 | parent = bridge_parent(out); |
646 | if (!parent) | |
647 | return NF_DROP; | |
648 | ||
516299d2 MM |
649 | if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) || |
650 | IS_PPPOE_IP(skb)) | |
1da177e4 | 651 | pf = PF_INET; |
a2bd40ad HX |
652 | else if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) || |
653 | IS_PPPOE_IPV6(skb)) | |
1da177e4 | 654 | pf = PF_INET6; |
a2bd40ad HX |
655 | else |
656 | return NF_ACCEPT; | |
1da177e4 | 657 | |
3db05fea | 658 | nf_bridge_pull_encap_header(skb); |
1da177e4 | 659 | |
1da177e4 LT |
660 | nf_bridge = skb->nf_bridge; |
661 | if (skb->pkt_type == PACKET_OTHERHOST) { | |
662 | skb->pkt_type = PACKET_HOST; | |
663 | nf_bridge->mask |= BRNF_PKT_TYPE; | |
664 | } | |
665 | ||
666 | /* The physdev module checks on this */ | |
667 | nf_bridge->mask |= BRNF_BRIDGED; | |
668 | nf_bridge->physoutdev = skb->dev; | |
669 | ||
6e23ae2a | 670 | NF_HOOK(pf, NF_INET_FORWARD, skb, bridge_parent(in), parent, |
5dce971a | 671 | br_nf_forward_finish); |
1da177e4 LT |
672 | |
673 | return NF_STOLEN; | |
674 | } | |
675 | ||
3db05fea | 676 | static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff *skb, |
789bc3e5 SH |
677 | const struct net_device *in, |
678 | const struct net_device *out, | |
679 | int (*okfn)(struct sk_buff *)) | |
1da177e4 | 680 | { |
1da177e4 LT |
681 | struct net_device **d = (struct net_device **)(skb->cb); |
682 | ||
683 | #ifdef CONFIG_SYSCTL | |
684 | if (!brnf_call_arptables) | |
685 | return NF_ACCEPT; | |
686 | #endif | |
687 | ||
f8a26028 | 688 | if (skb->protocol != htons(ETH_P_ARP)) { |
8b42ec39 | 689 | if (!IS_VLAN_ARP(skb)) |
1da177e4 | 690 | return NF_ACCEPT; |
3db05fea | 691 | nf_bridge_pull_encap_header(skb); |
1da177e4 LT |
692 | } |
693 | ||
d0a92be0 | 694 | if (arp_hdr(skb)->ar_pln != 4) { |
fc38582d | 695 | if (IS_VLAN_ARP(skb)) |
3db05fea | 696 | nf_bridge_push_encap_header(skb); |
1da177e4 LT |
697 | return NF_ACCEPT; |
698 | } | |
699 | *d = (struct net_device *)in; | |
fdc9314c | 700 | NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in, |
1da177e4 LT |
701 | (struct net_device *)out, br_nf_forward_finish); |
702 | ||
703 | return NF_STOLEN; | |
704 | } | |
705 | ||
c197facc | 706 | #if defined(CONFIG_NF_CONNTRACK_IPV4) || defined(CONFIG_NF_CONNTRACK_IPV4_MODULE) |
2e2f7aef PM |
707 | static int br_nf_dev_queue_xmit(struct sk_buff *skb) |
708 | { | |
c197facc | 709 | if (skb->nfct != NULL && |
710 | (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb)) && | |
2e2f7aef | 711 | skb->len > skb->dev->mtu && |
89114afd | 712 | !skb_is_gso(skb)) |
2e2f7aef PM |
713 | return ip_fragment(skb, br_dev_queue_push_xmit); |
714 | else | |
715 | return br_dev_queue_push_xmit(skb); | |
716 | } | |
c197facc | 717 | #else |
718 | static int br_nf_dev_queue_xmit(struct sk_buff *skb) | |
719 | { | |
720 | return br_dev_queue_push_xmit(skb); | |
721 | } | |
722 | #endif | |
1da177e4 LT |
723 | |
724 | /* PF_BRIDGE/POST_ROUTING ********************************************/ | |
3db05fea | 725 | static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff *skb, |
789bc3e5 SH |
726 | const struct net_device *in, |
727 | const struct net_device *out, | |
728 | int (*okfn)(struct sk_buff *)) | |
1da177e4 | 729 | { |
3db05fea | 730 | struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
1da177e4 | 731 | struct net_device *realoutdev = bridge_parent(skb->dev); |
76108cea | 732 | u_int8_t pf; |
1da177e4 | 733 | |
ea2d9b41 | 734 | if (!nf_bridge || !(nf_bridge->mask & BRNF_BRIDGED)) |
81d9ddae PM |
735 | return NF_ACCEPT; |
736 | ||
5dce971a SH |
737 | if (!realoutdev) |
738 | return NF_DROP; | |
739 | ||
516299d2 MM |
740 | if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) || |
741 | IS_PPPOE_IP(skb)) | |
1da177e4 | 742 | pf = PF_INET; |
a2bd40ad HX |
743 | else if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) || |
744 | IS_PPPOE_IPV6(skb)) | |
1da177e4 | 745 | pf = PF_INET6; |
a2bd40ad HX |
746 | else |
747 | return NF_ACCEPT; | |
1da177e4 | 748 | |
1da177e4 LT |
749 | /* We assume any code from br_dev_queue_push_xmit onwards doesn't care |
750 | * about the value of skb->pkt_type. */ | |
751 | if (skb->pkt_type == PACKET_OTHERHOST) { | |
752 | skb->pkt_type = PACKET_HOST; | |
753 | nf_bridge->mask |= BRNF_PKT_TYPE; | |
754 | } | |
755 | ||
fc38582d | 756 | nf_bridge_pull_encap_header(skb); |
1da177e4 LT |
757 | nf_bridge_save_header(skb); |
758 | ||
6e23ae2a | 759 | NF_HOOK(pf, NF_INET_POST_ROUTING, skb, NULL, realoutdev, |
2e2f7aef | 760 | br_nf_dev_queue_xmit); |
1da177e4 LT |
761 | |
762 | return NF_STOLEN; | |
1da177e4 LT |
763 | } |
764 | ||
1da177e4 LT |
765 | /* IP/SABOTAGE *****************************************************/ |
766 | /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING | |
767 | * for the second time. */ | |
3db05fea | 768 | static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff *skb, |
789bc3e5 SH |
769 | const struct net_device *in, |
770 | const struct net_device *out, | |
771 | int (*okfn)(struct sk_buff *)) | |
1da177e4 | 772 | { |
3db05fea HX |
773 | if (skb->nf_bridge && |
774 | !(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) { | |
1da177e4 LT |
775 | return NF_STOP; |
776 | } | |
777 | ||
778 | return NF_ACCEPT; | |
779 | } | |
780 | ||
ea2d9b41 BDS |
781 | /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because |
782 | * br_dev_queue_push_xmit is called afterwards */ | |
1999414a | 783 | static struct nf_hook_ops br_nf_ops[] __read_mostly = { |
1490fd89 CG |
784 | { |
785 | .hook = br_nf_pre_routing, | |
786 | .owner = THIS_MODULE, | |
787 | .pf = PF_BRIDGE, | |
788 | .hooknum = NF_BR_PRE_ROUTING, | |
789 | .priority = NF_BR_PRI_BRNF, | |
790 | }, | |
791 | { | |
792 | .hook = br_nf_local_in, | |
793 | .owner = THIS_MODULE, | |
794 | .pf = PF_BRIDGE, | |
795 | .hooknum = NF_BR_LOCAL_IN, | |
796 | .priority = NF_BR_PRI_BRNF, | |
797 | }, | |
798 | { | |
799 | .hook = br_nf_forward_ip, | |
800 | .owner = THIS_MODULE, | |
801 | .pf = PF_BRIDGE, | |
802 | .hooknum = NF_BR_FORWARD, | |
803 | .priority = NF_BR_PRI_BRNF - 1, | |
804 | }, | |
805 | { | |
806 | .hook = br_nf_forward_arp, | |
807 | .owner = THIS_MODULE, | |
808 | .pf = PF_BRIDGE, | |
809 | .hooknum = NF_BR_FORWARD, | |
810 | .priority = NF_BR_PRI_BRNF, | |
811 | }, | |
1490fd89 CG |
812 | { |
813 | .hook = br_nf_post_routing, | |
814 | .owner = THIS_MODULE, | |
815 | .pf = PF_BRIDGE, | |
816 | .hooknum = NF_BR_POST_ROUTING, | |
817 | .priority = NF_BR_PRI_LAST, | |
818 | }, | |
819 | { | |
820 | .hook = ip_sabotage_in, | |
821 | .owner = THIS_MODULE, | |
822 | .pf = PF_INET, | |
823 | .hooknum = NF_INET_PRE_ROUTING, | |
824 | .priority = NF_IP_PRI_FIRST, | |
825 | }, | |
826 | { | |
827 | .hook = ip_sabotage_in, | |
828 | .owner = THIS_MODULE, | |
829 | .pf = PF_INET6, | |
830 | .hooknum = NF_INET_PRE_ROUTING, | |
831 | .priority = NF_IP6_PRI_FIRST, | |
832 | }, | |
1da177e4 LT |
833 | }; |
834 | ||
835 | #ifdef CONFIG_SYSCTL | |
836 | static | |
8d65af78 | 837 | int brnf_sysctl_call_tables(ctl_table * ctl, int write, |
789bc3e5 | 838 | void __user * buffer, size_t * lenp, loff_t * ppos) |
1da177e4 LT |
839 | { |
840 | int ret; | |
841 | ||
8d65af78 | 842 | ret = proc_dointvec(ctl, write, buffer, lenp, ppos); |
1da177e4 LT |
843 | |
844 | if (write && *(int *)(ctl->data)) | |
845 | *(int *)(ctl->data) = 1; | |
846 | return ret; | |
847 | } | |
848 | ||
849 | static ctl_table brnf_table[] = { | |
850 | { | |
1da177e4 LT |
851 | .procname = "bridge-nf-call-arptables", |
852 | .data = &brnf_call_arptables, | |
853 | .maxlen = sizeof(int), | |
854 | .mode = 0644, | |
6d9f239a | 855 | .proc_handler = brnf_sysctl_call_tables, |
1da177e4 LT |
856 | }, |
857 | { | |
1da177e4 LT |
858 | .procname = "bridge-nf-call-iptables", |
859 | .data = &brnf_call_iptables, | |
860 | .maxlen = sizeof(int), | |
861 | .mode = 0644, | |
6d9f239a | 862 | .proc_handler = brnf_sysctl_call_tables, |
1da177e4 LT |
863 | }, |
864 | { | |
1da177e4 LT |
865 | .procname = "bridge-nf-call-ip6tables", |
866 | .data = &brnf_call_ip6tables, | |
867 | .maxlen = sizeof(int), | |
868 | .mode = 0644, | |
6d9f239a | 869 | .proc_handler = brnf_sysctl_call_tables, |
1da177e4 LT |
870 | }, |
871 | { | |
1da177e4 LT |
872 | .procname = "bridge-nf-filter-vlan-tagged", |
873 | .data = &brnf_filter_vlan_tagged, | |
874 | .maxlen = sizeof(int), | |
875 | .mode = 0644, | |
6d9f239a | 876 | .proc_handler = brnf_sysctl_call_tables, |
516299d2 MM |
877 | }, |
878 | { | |
516299d2 MM |
879 | .procname = "bridge-nf-filter-pppoe-tagged", |
880 | .data = &brnf_filter_pppoe_tagged, | |
881 | .maxlen = sizeof(int), | |
882 | .mode = 0644, | |
6d9f239a | 883 | .proc_handler = brnf_sysctl_call_tables, |
1da177e4 | 884 | }, |
f8572d8f | 885 | { } |
1da177e4 LT |
886 | }; |
887 | ||
b5ccd792 | 888 | static struct ctl_path brnf_path[] = { |
f8572d8f EB |
889 | { .procname = "net", }, |
890 | { .procname = "bridge", }, | |
b5ccd792 | 891 | { } |
1da177e4 LT |
892 | }; |
893 | #endif | |
894 | ||
5eb87f45 | 895 | int __init br_netfilter_init(void) |
1da177e4 | 896 | { |
5eb87f45 | 897 | int ret; |
1da177e4 | 898 | |
5eb87f45 PM |
899 | ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops)); |
900 | if (ret < 0) | |
1da177e4 | 901 | return ret; |
1da177e4 | 902 | #ifdef CONFIG_SYSCTL |
b5ccd792 | 903 | brnf_sysctl_header = register_sysctl_paths(brnf_path, brnf_table); |
1da177e4 | 904 | if (brnf_sysctl_header == NULL) { |
789bc3e5 SH |
905 | printk(KERN_WARNING |
906 | "br_netfilter: can't register to sysctl.\n"); | |
5eb87f45 PM |
907 | nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops)); |
908 | return -ENOMEM; | |
1da177e4 LT |
909 | } |
910 | #endif | |
1da177e4 | 911 | printk(KERN_NOTICE "Bridge firewalling registered\n"); |
1da177e4 LT |
912 | return 0; |
913 | } | |
914 | ||
915 | void br_netfilter_fini(void) | |
916 | { | |
5eb87f45 | 917 | nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops)); |
1da177e4 LT |
918 | #ifdef CONFIG_SYSCTL |
919 | unregister_sysctl_table(brnf_sysctl_header); | |
920 | #endif | |
921 | } |