]> bbs.cooldavid.org Git - net-next-2.6.git/blame - net/bridge/br_netfilter.c
git://bbs.cooldavid.org / net-next-2.6.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
[IPV4]: Make struct sockaddr_in::sin_port __be16
[net-next-2.6.git] / net / bridge / br_netfilter.c
CommitLineData
1da177e4
LT		 1/*
2 * Handle firewalling
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 * Bart De Schuymer (maintainer) <bdschuym@pandora.be>
8 *
9 * Changes:
10 * Apr 29 2003: physdev module support (bdschuym)
11 * Jun 19 2003: let arptables see bridged ARP traffic (bdschuym)
12 * Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge
13 * (bdschuym)
14 * Sep 01 2004: add IPv6 filtering (bdschuym)
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
20 *
21 * Lennert dedicates this file to Kerstin Wurdinger.
22 */
23
24#include <linux/module.h>
25#include <linux/kernel.h>
26#include <linux/ip.h>
27#include <linux/netdevice.h>
28#include <linux/skbuff.h>
14c85021 29#include <linux/if_arp.h>
1da177e4
LT		 30#include <linux/if_ether.h>
31#include <linux/if_vlan.h>
32#include <linux/netfilter_bridge.h>
33#include <linux/netfilter_ipv4.h>
34#include <linux/netfilter_ipv6.h>
35#include <linux/netfilter_arp.h>
36#include <linux/in_route.h>
14c85021 37
1da177e4
LT		 38#include <net/ip.h>
39#include <net/ipv6.h>
14c85021
ACM		 40#include <net/route.h>
41
1da177e4
LT		 42#include <asm/uaccess.h>
43#include <asm/checksum.h>
44#include "br_private.h"
45#ifdef CONFIG_SYSCTL
46#include <linux/sysctl.h>
47#endif
48
49#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
50 (skb->nf_bridge->data))->daddr.ipv4)
51#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
52#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
53
1da177e4
LT		 54#ifdef CONFIG_SYSCTL
55static struct ctl_table_header *brnf_sysctl_header;
56static int brnf_call_iptables = 1;
57static int brnf_call_ip6tables = 1;
58static int brnf_call_arptables = 1;
59static int brnf_filter_vlan_tagged = 1;
60#else
61#define brnf_filter_vlan_tagged 1
62#endif
63
10ea6ac8
PM		 64int brnf_deferred_hooks;
65EXPORT_SYMBOL_GPL(brnf_deferred_hooks);
66
8b42ec39
SH		 67static __be16 inline vlan_proto(const struct sk_buff *skb)
68{
69 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
70}
71
72#define IS_VLAN_IP(skb) \
73 (skb->protocol == htons(ETH_P_8021Q) && \
74 vlan_proto(skb) == htons(ETH_P_IP) && \
75 brnf_filter_vlan_tagged)
76
77#define IS_VLAN_IPV6(skb) \
78 (skb->protocol == htons(ETH_P_8021Q) && \
79 vlan_proto(skb) == htons(ETH_P_IPV6) &&\
80 brnf_filter_vlan_tagged)
81
82#define IS_VLAN_ARP(skb) \
83 (skb->protocol == htons(ETH_P_8021Q) && \
84 vlan_proto(skb) == htons(ETH_P_ARP) && \
85 brnf_filter_vlan_tagged)
1da177e4
LT		 86
87/* We need these fake structures to make netfilter happy --
88 * lots of places assume that skb->dst != NULL, which isn't
89 * all that unreasonable.
90 *
91 * Currently, we fill in the PMTU entry because netfilter
92 * refragmentation needs it, and the rt_flags entry because
93 * ipt_REJECT needs it. Future netfilter modules might
94 * require us to fill additional fields. */
95static struct net_device __fake_net_device = {
96 .hard_header_len = ETH_HLEN
97};
98
99static struct rtable __fake_rtable = {
100 .u = {
101 .dst = {
102 .__refcnt = ATOMIC_INIT(1),
103 .dev = &__fake_net_device,
104 .path = &__fake_rtable.u.dst,
105 .metrics = {[RTAX_MTU - 1] = 1500},
42cf93cd 106 .flags = DST_NOXFRM,
1da177e4
LT		 107 }
108 },
109 .rt_flags = 0,
110};
111
5dce971a
SH		 112static inline struct net_device *bridge_parent(const struct net_device *dev)
113{
114 struct net_bridge_port *port = rcu_dereference(dev->br_port);
115
116 return port ? port->br->dev : NULL;
117}
1da177e4 118
fdeabdef
SH		 119static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
120{
121 skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
122 if (likely(skb->nf_bridge))
123 atomic_set(&(skb->nf_bridge->use), 1);
124
125 return skb->nf_bridge;
126}
127
128static inline void nf_bridge_save_header(struct sk_buff *skb)
129{
130 int header_size = 16;
131
132 if (skb->protocol == htons(ETH_P_8021Q))
133 header_size = 18;
134
135 memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
136}
137
1da177e4
LT		 138/* PF_BRIDGE/PRE_ROUTING *********************************************/
139/* Undo the changes made for ip6tables PREROUTING and continue the
140 * bridge PRE_ROUTING hook. */
141static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
142{
143 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
144
1da177e4
LT		 145 if (nf_bridge->mask & BRNF_PKT_TYPE) {
146 skb->pkt_type = PACKET_OTHERHOST;
147 nf_bridge->mask ^= BRNF_PKT_TYPE;
148 }
149 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
150
151 skb->dst = (struct dst_entry *)&__fake_rtable;
152 dst_hold(skb->dst);
153
154 skb->dev = nf_bridge->physindev;
f8a26028 155 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 156 skb_push(skb, VLAN_HLEN);
157 skb->nh.raw -= VLAN_HLEN;
158 }
159 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
160 br_handle_frame_finish, 1);
161
162 return 0;
163}
164
165static void __br_dnat_complain(void)
166{
167 static unsigned long last_complaint;
168
169 if (jiffies - last_complaint >= 5 * HZ) {
170 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
789bc3e5 171 "forwarding to be enabled\n");
1da177e4
LT		 172 last_complaint = jiffies;
173 }
174}
175
176/* This requires some explaining. If DNAT has taken place,
177 * we will need to fix up the destination Ethernet address,
178 * and this is a tricky process.
179 *
180 * There are two cases to consider:
181 * 1. The packet was DNAT'ed to a device in the same bridge
182 * port group as it was received on. We can still bridge
183 * the packet.
184 * 2. The packet was DNAT'ed to a different device, either
185 * a non-bridged device or another bridge port group.
186 * The packet will need to be routed.
187 *
188 * The correct way of distinguishing between these two cases is to
189 * call ip_route_input() and to look at skb->dst->dev, which is
190 * changed to the destination device if ip_route_input() succeeds.
191 *
192 * Let us first consider the case that ip_route_input() succeeds:
193 *
194 * If skb->dst->dev equals the logical bridge device the packet
195 * came in on, we can consider this bridging. We then call
196 * skb->dst->output() which will make the packet enter br_nf_local_out()
197 * not much later. In that function it is assured that the iptables
198 * FORWARD chain is traversed for the packet.
199 *
200 * Otherwise, the packet is considered to be routed and we just
201 * change the destination MAC address so that the packet will
202 * later be passed up to the IP stack to be routed.
203 *
204 * Let us now consider the case that ip_route_input() fails:
205 *
206 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
207 * will fail, while __ip_route_output_key() will return success. The source
208 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
209 * thinks we're handling a locally generated packet and won't care
210 * if IP forwarding is allowed. We send a warning message to the users's
211 * log telling her to put IP forwarding on.
212 *
213 * ip_route_input() will also fail if there is no route available.
214 * In that case we just drop the packet.
215 *
216 * --Lennert, 20020411
217 * --Bart, 20020416 (updated)
218 * --Bart, 20021007 (updated) */
219static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
220{
1da177e4
LT		 221 if (skb->pkt_type == PACKET_OTHERHOST) {
222 skb->pkt_type = PACKET_HOST;
223 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
224 }
225 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
226
227 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 228 if (!skb->dev)
229 kfree_skb(skb);
230 else {
f8a26028 231 if (skb->protocol == htons(ETH_P_8021Q)) {
5dce971a
SH		 232 skb_pull(skb, VLAN_HLEN);
233 skb->nh.raw += VLAN_HLEN;
234 }
235 skb->dst->output(skb);
1da177e4 236 }
1da177e4
LT		 237 return 0;
238}
239
240static int br_nf_pre_routing_finish(struct sk_buff *skb)
241{
242 struct net_device *dev = skb->dev;
243 struct iphdr *iph = skb->nh.iph;
244 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
245
1da177e4
LT		 246 if (nf_bridge->mask & BRNF_PKT_TYPE) {
247 skb->pkt_type = PACKET_OTHERHOST;
248 nf_bridge->mask ^= BRNF_PKT_TYPE;
249 }
250 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
251
252 if (dnat_took_place(skb)) {
789bc3e5 253 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev)) {
1da177e4 254 struct rtable *rt;
789bc3e5
SH		 255 struct flowi fl = {
256 .nl_u = {
257 .ip4_u = {
258 .daddr = iph->daddr,
259 .saddr = 0,
260 .tos = RT_TOS(iph->tos) },
261 },
262 .proto = 0,
263 };
1da177e4
LT		 264
265 if (!ip_route_output_key(&rt, &fl)) {
1c011bed
BDS		 266 /* - Bridged-and-DNAT'ed traffic doesn't
267 * require ip_forwarding.
268 * - Deal with redirected traffic. */
269 if (((struct dst_entry *)rt)->dev == dev ||
270 rt->rt_type == RTN_LOCAL) {
1da177e4
LT		 271 skb->dst = (struct dst_entry *)rt;
272 goto bridged_dnat;
273 }
274 __br_dnat_complain();
275 dst_release((struct dst_entry *)rt);
276 }
277 kfree_skb(skb);
278 return 0;
279 } else {
280 if (skb->dst->dev == dev) {
281bridged_dnat:
282 /* Tell br_nf_local_out this is a
283 * bridged frame */
284 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
285 skb->dev = nf_bridge->physindev;
286 if (skb->protocol ==
f8a26028 287 htons(ETH_P_8021Q)) {
1da177e4
LT		 288 skb_push(skb, VLAN_HLEN);
289 skb->nh.raw -= VLAN_HLEN;
290 }
291 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
292 skb, skb->dev, NULL,
293 br_nf_pre_routing_finish_bridge,
294 1);
295 return 0;
296 }
789bc3e5 297 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
1da177e4
LT		 298 skb->pkt_type = PACKET_HOST;
299 }
300 } else {
301 skb->dst = (struct dst_entry *)&__fake_rtable;
302 dst_hold(skb->dst);
303 }
304
305 skb->dev = nf_bridge->physindev;
f8a26028 306 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 307 skb_push(skb, VLAN_HLEN);
308 skb->nh.raw -= VLAN_HLEN;
309 }
310 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
311 br_handle_frame_finish, 1);
312
313 return 0;
314}
315
316/* Some common code for IPv4/IPv6 */
5dce971a 317static struct net_device *setup_pre_routing(struct sk_buff *skb)
1da177e4
LT		 318{
319 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
320
321 if (skb->pkt_type == PACKET_OTHERHOST) {
322 skb->pkt_type = PACKET_HOST;
323 nf_bridge->mask |= BRNF_PKT_TYPE;
324 }
325
326 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
327 nf_bridge->physindev = skb->dev;
328 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 329
330 return skb->dev;
1da177e4
LT		 331}
332
333/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
334static int check_hbh_len(struct sk_buff *skb)
335{
789bc3e5 336 unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
1da177e4
LT		 337 u32 pkt_len;
338 int off = raw - skb->nh.raw;
789bc3e5 339 int len = (raw[1] + 1) << 3;
1da177e4
LT		 340
341 if ((raw + len) - skb->data > skb_headlen(skb))
342 goto bad;
343
344 off += 2;
345 len -= 2;
346
347 while (len > 0) {
789bc3e5 348 int optlen = skb->nh.raw[off + 1] + 2;
1da177e4
LT		 349
350 switch (skb->nh.raw[off]) {
351 case IPV6_TLV_PAD0:
352 optlen = 1;
353 break;
354
355 case IPV6_TLV_PADN:
356 break;
357
358 case IPV6_TLV_JUMBO:
789bc3e5 359 if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
1da177e4 360 goto bad;
789bc3e5 361 pkt_len = ntohl(*(u32 *) (skb->nh.raw + off + 2));
b0366486
BDS		 362 if (pkt_len <= IPV6_MAXPLEN ||
363 skb->nh.ipv6h->payload_len)
364 goto bad;
1da177e4
LT		 365 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
366 goto bad;
b0366486 367 if (pskb_trim_rcsum(skb,
789bc3e5 368 pkt_len + sizeof(struct ipv6hdr)))
b0366486 369 goto bad;
1da177e4
LT		 370 break;
371 default:
372 if (optlen > len)
373 goto bad;
374 break;
375 }
376 off += optlen;
377 len -= optlen;
378 }
379 if (len == 0)
380 return 0;
381bad:
382 return -1;
383
384}
385
386/* Replicate the checks that IPv6 does on packet reception and pass the packet
387 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
388static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
789bc3e5
SH		 389 struct sk_buff *skb,
390 const struct net_device *in,
391 const struct net_device *out,
392 int (*okfn)(struct sk_buff *))
1da177e4
LT		 393{
394 struct ipv6hdr *hdr;
395 u32 pkt_len;
1da177e4
LT		 396
397 if (skb->len < sizeof(struct ipv6hdr))
398 goto inhdr_error;
399
400 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
401 goto inhdr_error;
402
403 hdr = skb->nh.ipv6h;
404
405 if (hdr->version != 6)
406 goto inhdr_error;
407
408 pkt_len = ntohs(hdr->payload_len);
409
410 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
411 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
412 goto inhdr_error;
b38dfee3
HX		 413 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
414 goto inhdr_error;
1da177e4
LT		 415 }
416 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
789bc3e5 417 goto inhdr_error;
1da177e4 418
789bc3e5 419 nf_bridge_put(skb->nf_bridge);
fdeabdef 420 if (!nf_bridge_alloc(skb))
1da177e4 421 return NF_DROP;
5dce971a
SH		 422 if (!setup_pre_routing(skb))
423 return NF_DROP;
1da177e4
LT		 424
425 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
426 br_nf_pre_routing_finish_ipv6);
427
428 return NF_STOLEN;
429
430inhdr_error:
431 return NF_DROP;
432}
433
434/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
435 * Replicate the checks that IPv4 does on packet reception.
436 * Set skb->dev to the bridge device (i.e. parent of the
437 * receiving device) to make netfilter happy, the REDIRECT
438 * target in particular. Save the original destination IP
439 * address to be able to detect DNAT afterwards. */
440static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
ee02b3a6
SH		 441 const struct net_device *in,
442 const struct net_device *out,
443 int (*okfn)(struct sk_buff *))
1da177e4
LT		 444{
445 struct iphdr *iph;
446 __u32 len;
447 struct sk_buff *skb = *pskb;
1da177e4 448
8b42ec39 449 if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
1da177e4
LT		 450#ifdef CONFIG_SYSCTL
451 if (!brnf_call_ip6tables)
452 return NF_ACCEPT;
453#endif
454 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
455 goto out;
456
f8a26028 457 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 458 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 459 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 460 }
461 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
462 }
463#ifdef CONFIG_SYSCTL
464 if (!brnf_call_iptables)
465 return NF_ACCEPT;
466#endif
467
8b42ec39 468 if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
1da177e4
LT		 469 return NF_ACCEPT;
470
471 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
472 goto out;
473
f8a26028 474 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 475 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 476 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 477 }
478
479 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
480 goto inhdr_error;
481
482 iph = skb->nh.iph;
483 if (iph->ihl < 5 || iph->version != 4)
484 goto inhdr_error;
485
789bc3e5 486 if (!pskb_may_pull(skb, 4 * iph->ihl))
1da177e4
LT		 487 goto inhdr_error;
488
489 iph = skb->nh.iph;
789bc3e5 490 if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
1da177e4
LT		 491 goto inhdr_error;
492
493 len = ntohs(iph->tot_len);
789bc3e5 494 if (skb->len < len || len < 4 * iph->ihl)
1da177e4
LT		 495 goto inhdr_error;
496
b38dfee3 497 pskb_trim_rcsum(skb, len);
1da177e4 498
789bc3e5 499 nf_bridge_put(skb->nf_bridge);
fdeabdef 500 if (!nf_bridge_alloc(skb))
1da177e4 501 return NF_DROP;
5dce971a
SH		 502 if (!setup_pre_routing(skb))
503 return NF_DROP;
1da177e4
LT		 504 store_orig_dstaddr(skb);
505
506 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
507 br_nf_pre_routing_finish);
508
509 return NF_STOLEN;
510
511inhdr_error:
789bc3e5 512// IP_INC_STATS_BH(IpInHdrErrors);
1da177e4
LT		 513out:
514 return NF_DROP;
515}
516
517
518/* PF_BRIDGE/LOCAL_IN ************************************************/
519/* The packet is locally destined, which requires a real
520 * dst_entry, so detach the fake one. On the way up, the
521 * packet would pass through PRE_ROUTING again (which already
522 * took place when the packet entered the bridge), but we
523 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
524 * prevent this from happening. */
525static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 526 const struct net_device *in,
527 const struct net_device *out,
528 int (*okfn)(struct sk_buff *))
1da177e4
LT		 529{
530 struct sk_buff *skb = *pskb;
531
532 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
533 dst_release(skb->dst);
534 skb->dst = NULL;
535 }
536
537 return NF_ACCEPT;
538}
539
1da177e4
LT		 540/* PF_BRIDGE/FORWARD *************************************************/
541static int br_nf_forward_finish(struct sk_buff *skb)
542{
543 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
544 struct net_device *in;
1da177e4 545
8b42ec39 546 if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
1da177e4
LT		 547 in = nf_bridge->physindev;
548 if (nf_bridge->mask & BRNF_PKT_TYPE) {
549 skb->pkt_type = PACKET_OTHERHOST;
550 nf_bridge->mask ^= BRNF_PKT_TYPE;
551 }
552 } else {
553 in = *((struct net_device **)(skb->cb));
554 }
f8a26028 555 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 556 skb_push(skb, VLAN_HLEN);
557 skb->nh.raw -= VLAN_HLEN;
558 }
559 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
789bc3e5 560 skb->dev, br_forward_finish, 1);
1da177e4
LT		 561 return 0;
562}
563
564/* This is the 'purely bridged' case. For IP, we pass the packet to
565 * netfilter with indev and outdev set to the bridge device,
566 * but we are still able to filter on the 'real' indev/outdev
567 * because of the physdev module. For ARP, indev and outdev are the
568 * bridge ports. */
569static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 570 const struct net_device *in,
571 const struct net_device *out,
572 int (*okfn)(struct sk_buff *))
1da177e4
LT		 573{
574 struct sk_buff *skb = *pskb;
575 struct nf_bridge_info *nf_bridge;
5dce971a 576 struct net_device *parent;
1da177e4
LT		 577 int pf;
578
579 if (!skb->nf_bridge)
580 return NF_ACCEPT;
581
5dce971a
SH		 582 parent = bridge_parent(out);
583 if (!parent)
584 return NF_DROP;
585
8b42ec39 586 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 587 pf = PF_INET;
588 else
589 pf = PF_INET6;
590
f8a26028 591 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 592 skb_pull(*pskb, VLAN_HLEN);
593 (*pskb)->nh.raw += VLAN_HLEN;
594 }
595
1da177e4
LT		 596 nf_bridge = skb->nf_bridge;
597 if (skb->pkt_type == PACKET_OTHERHOST) {
598 skb->pkt_type = PACKET_HOST;
599 nf_bridge->mask |= BRNF_PKT_TYPE;
600 }
601
602 /* The physdev module checks on this */
603 nf_bridge->mask |= BRNF_BRIDGED;
604 nf_bridge->physoutdev = skb->dev;
605
5dce971a
SH		 606 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
607 br_nf_forward_finish);
1da177e4
LT		 608
609 return NF_STOLEN;
610}
611
612static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 613 const struct net_device *in,
614 const struct net_device *out,
615 int (*okfn)(struct sk_buff *))
1da177e4
LT		 616{
617 struct sk_buff *skb = *pskb;
1da177e4
LT		 618 struct net_device **d = (struct net_device **)(skb->cb);
619
620#ifdef CONFIG_SYSCTL
621 if (!brnf_call_arptables)
622 return NF_ACCEPT;
623#endif
624
f8a26028 625 if (skb->protocol != htons(ETH_P_ARP)) {
8b42ec39 626 if (!IS_VLAN_ARP(skb))
1da177e4
LT		 627 return NF_ACCEPT;
628 skb_pull(*pskb, VLAN_HLEN);
629 (*pskb)->nh.raw += VLAN_HLEN;
630 }
631
1da177e4 632 if (skb->nh.arph->ar_pln != 4) {
8b42ec39 633 if (IS_VLAN_ARP(skb)) {
1da177e4
LT		 634 skb_push(*pskb, VLAN_HLEN);
635 (*pskb)->nh.raw -= VLAN_HLEN;
636 }
637 return NF_ACCEPT;
638 }
639 *d = (struct net_device *)in;
640 NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
641 (struct net_device *)out, br_nf_forward_finish);
642
643 return NF_STOLEN;
644}
645
1da177e4
LT		 646/* PF_BRIDGE/LOCAL_OUT ***********************************************/
647static int br_nf_local_out_finish(struct sk_buff *skb)
648{
f8a26028 649 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 650 skb_push(skb, VLAN_HLEN);
651 skb->nh.raw -= VLAN_HLEN;
652 }
653
654 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
789bc3e5 655 br_forward_finish, NF_BR_PRI_FIRST + 1);
1da177e4
LT		 656
657 return 0;
658}
659
660/* This function sees both locally originated IP packets and forwarded
661 * IP packets (in both cases the destination device is a bridge
662 * device). It also sees bridged-and-DNAT'ed packets.
663 * To be able to filter on the physical bridge devices (with the physdev
664 * module), we steal packets destined to a bridge device away from the
665 * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
666 * when we have determined the real output device. This is done in here.
667 *
668 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
669 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
670 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
671 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
672 * will be executed.
673 * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
674 * this packet before, and so the packet was locally originated. We fake
675 * the PF_INET/LOCAL_OUT hook.
676 * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
677 * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
678 * even routed packets that didn't arrive on a bridge interface have their
679 * nf_bridge->physindev set. */
680static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 681 const struct net_device *in,
682 const struct net_device *out,
683 int (*okfn)(struct sk_buff *))
1da177e4
LT		 684{
685 struct net_device *realindev, *realoutdev;
686 struct sk_buff *skb = *pskb;
687 struct nf_bridge_info *nf_bridge;
1da177e4
LT		 688 int pf;
689
690 if (!skb->nf_bridge)
691 return NF_ACCEPT;
692
8b42ec39 693 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 694 pf = PF_INET;
695 else
696 pf = PF_INET6;
697
698#ifdef CONFIG_NETFILTER_DEBUG
699 /* Sometimes we get packets with NULL ->dst here (for example,
700 * running a dhcp client daemon triggers this). This should now
701 * be fixed, but let's keep the check around. */
702 if (skb->dst == NULL) {
703 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
704 return NF_ACCEPT;
705 }
706#endif
707
708 nf_bridge = skb->nf_bridge;
709 nf_bridge->physoutdev = skb->dev;
710 realindev = nf_bridge->physindev;
711
712 /* Bridged, take PF_BRIDGE/FORWARD.
713 * (see big note in front of br_nf_pre_routing_finish) */
714 if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
715 if (nf_bridge->mask & BRNF_PKT_TYPE) {
716 skb->pkt_type = PACKET_OTHERHOST;
717 nf_bridge->mask ^= BRNF_PKT_TYPE;
718 }
f8a26028 719 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 720 skb_push(skb, VLAN_HLEN);
721 skb->nh.raw -= VLAN_HLEN;
722 }
723
724 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
725 skb->dev, br_forward_finish);
726 goto out;
727 }
728 realoutdev = bridge_parent(skb->dev);
5dce971a
SH		 729 if (!realoutdev)
730 return NF_DROP;
1da177e4
LT		 731
732#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
733 /* iptables should match -o br0.x */
734 if (nf_bridge->netoutdev)
735 realoutdev = nf_bridge->netoutdev;
736#endif
f8a26028 737 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 738 skb_pull(skb, VLAN_HLEN);
739 (*pskb)->nh.raw += VLAN_HLEN;
740 }
741 /* IP forwarded traffic has a physindev, locally
742 * generated traffic hasn't. */
743 if (realindev != NULL) {
789bc3e5 744 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT)) {
5dce971a
SH		 745 struct net_device *parent = bridge_parent(realindev);
746 if (parent)
747 realindev = parent;
748 }
1da177e4
LT		 749
750 NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
751 realoutdev, br_nf_local_out_finish,
752 NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
753 } else {
1da177e4
LT		 754 NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
755 realoutdev, br_nf_local_out_finish,
756 NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
757 }
758
759out:
760 return NF_STOLEN;
761}
762
2e2f7aef
PM		 763static int br_nf_dev_queue_xmit(struct sk_buff *skb)
764{
765 if (skb->protocol == htons(ETH_P_IP) &&
766 skb->len > skb->dev->mtu &&
89114afd 767 !skb_is_gso(skb))
2e2f7aef
PM		 768 return ip_fragment(skb, br_dev_queue_push_xmit);
769 else
770 return br_dev_queue_push_xmit(skb);
771}
1da177e4
LT		 772
773/* PF_BRIDGE/POST_ROUTING ********************************************/
774static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 775 const struct net_device *in,
776 const struct net_device *out,
777 int (*okfn)(struct sk_buff *))
1da177e4
LT		 778{
779 struct sk_buff *skb = *pskb;
780 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
1da177e4
LT		 781 struct net_device *realoutdev = bridge_parent(skb->dev);
782 int pf;
783
784#ifdef CONFIG_NETFILTER_DEBUG
785 /* Be very paranoid. This probably won't happen anymore, but let's
786 * keep the check just to be sure... */
787 if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
788 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
789bc3e5 789 "bad mac.raw pointer.");
1da177e4
LT		 790 goto print_error;
791 }
792#endif
793
794 if (!nf_bridge)
795 return NF_ACCEPT;
796
5dce971a
SH		 797 if (!realoutdev)
798 return NF_DROP;
799
8b42ec39 800 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 801 pf = PF_INET;
802 else
803 pf = PF_INET6;
804
805#ifdef CONFIG_NETFILTER_DEBUG
806 if (skb->dst == NULL) {
807 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
808 goto print_error;
809 }
1da177e4
LT		 810#endif
811
812 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
813 * about the value of skb->pkt_type. */
814 if (skb->pkt_type == PACKET_OTHERHOST) {
815 skb->pkt_type = PACKET_HOST;
816 nf_bridge->mask |= BRNF_PKT_TYPE;
817 }
818
f8a26028 819 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 820 skb_pull(skb, VLAN_HLEN);
821 skb->nh.raw += VLAN_HLEN;
822 }
823
824 nf_bridge_save_header(skb);
825
826#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
827 if (nf_bridge->netoutdev)
828 realoutdev = nf_bridge->netoutdev;
829#endif
830 NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
2e2f7aef 831 br_nf_dev_queue_xmit);
1da177e4
LT		 832
833 return NF_STOLEN;
834
835#ifdef CONFIG_NETFILTER_DEBUG
836print_error:
837 if (skb->dev != NULL) {
838 printk("[%s]", skb->dev->name);
178a3259
SH		 839 if (realoutdev)
840 printk("[%s]", realoutdev->name);
1da177e4
LT		 841 }
842 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
789bc3e5 843 skb->data);
1da177e4
LT		 844 return NF_ACCEPT;
845#endif
846}
847
1da177e4
LT		 848/* IP/SABOTAGE *****************************************************/
849/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
850 * for the second time. */
851static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 852 const struct net_device *in,
853 const struct net_device *out,
854 int (*okfn)(struct sk_buff *))
1da177e4
LT		 855{
856 if ((*pskb)->nf_bridge &&
857 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
858 return NF_STOP;
859 }
860
861 return NF_ACCEPT;
862}
863
864/* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
865 * and PF_INET(6)/POST_ROUTING until we have done the forwarding
866 * decision in the bridge code and have determined nf_bridge->physoutdev. */
867static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 868 const struct net_device *in,
869 const struct net_device *out,
870 int (*okfn)(struct sk_buff *))
1da177e4
LT		 871{
872 struct sk_buff *skb = *pskb;
873
874 if ((out->hard_start_xmit == br_dev_xmit &&
789bc3e5 875 okfn != br_nf_forward_finish &&
2e2f7aef 876 okfn != br_nf_local_out_finish && okfn != br_nf_dev_queue_xmit)
1da177e4
LT		 877#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
878 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
789bc3e5 879 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
1da177e4
LT		 880#endif
881 ) {
882 struct nf_bridge_info *nf_bridge;
883
884 if (!skb->nf_bridge) {
885#ifdef CONFIG_SYSCTL
886 /* This code is executed while in the IP(v6) stack,
887 the version should be 4 or 6. We can't use
888 skb->protocol because that isn't set on
889 PF_INET(6)/LOCAL_OUT. */
890 struct iphdr *ip = skb->nh.iph;
891
892 if (ip->version == 4 && !brnf_call_iptables)
893 return NF_ACCEPT;
894 else if (ip->version == 6 && !brnf_call_ip6tables)
895 return NF_ACCEPT;
10ea6ac8
PM		 896 else if (!brnf_deferred_hooks)
897 return NF_ACCEPT;
1da177e4
LT		 898#endif
899 if (hook == NF_IP_POST_ROUTING)
900 return NF_ACCEPT;
901 if (!nf_bridge_alloc(skb))
902 return NF_DROP;
903 }
904
905 nf_bridge = skb->nf_bridge;
906
907 /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
908 * will need the indev then. For a brouter, the real indev
909 * can be a bridge port, so we make sure br_nf_local_out()
910 * doesn't use the bridge parent of the indev by using
911 * the BRNF_DONT_TAKE_PARENT mask. */
912 if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
9666dae5 913 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
1da177e4
LT		 914 nf_bridge->physindev = (struct net_device *)in;
915 }
916#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
917 /* the iptables outdev is br0.x, not br0 */
918 if (out->priv_flags & IFF_802_1Q_VLAN)
919 nf_bridge->netoutdev = (struct net_device *)out;
920#endif
921 return NF_STOP;
922 }
923
924 return NF_ACCEPT;
925}
926
927/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
928 * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
929 * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
930 * ip_refrag() can return NF_STOLEN. */
931static struct nf_hook_ops br_nf_ops[] = {
932 { .hook = br_nf_pre_routing,
933 .owner = THIS_MODULE,
934 .pf = PF_BRIDGE,
935 .hooknum = NF_BR_PRE_ROUTING,
936 .priority = NF_BR_PRI_BRNF, },
937 { .hook = br_nf_local_in,
938 .owner = THIS_MODULE,
939 .pf = PF_BRIDGE,
940 .hooknum = NF_BR_LOCAL_IN,
941 .priority = NF_BR_PRI_BRNF, },
942 { .hook = br_nf_forward_ip,
943 .owner = THIS_MODULE,
944 .pf = PF_BRIDGE,
945 .hooknum = NF_BR_FORWARD,
946 .priority = NF_BR_PRI_BRNF - 1, },
947 { .hook = br_nf_forward_arp,
948 .owner = THIS_MODULE,
949 .pf = PF_BRIDGE,
950 .hooknum = NF_BR_FORWARD,
951 .priority = NF_BR_PRI_BRNF, },
952 { .hook = br_nf_local_out,
953 .owner = THIS_MODULE,
954 .pf = PF_BRIDGE,
955 .hooknum = NF_BR_LOCAL_OUT,
956 .priority = NF_BR_PRI_FIRST, },
957 { .hook = br_nf_post_routing,
958 .owner = THIS_MODULE,
959 .pf = PF_BRIDGE,
960 .hooknum = NF_BR_POST_ROUTING,
961 .priority = NF_BR_PRI_LAST, },
962 { .hook = ip_sabotage_in,
963 .owner = THIS_MODULE,
964 .pf = PF_INET,
965 .hooknum = NF_IP_PRE_ROUTING,
966 .priority = NF_IP_PRI_FIRST, },
967 { .hook = ip_sabotage_in,
968 .owner = THIS_MODULE,
969 .pf = PF_INET6,
970 .hooknum = NF_IP6_PRE_ROUTING,
971 .priority = NF_IP6_PRI_FIRST, },
972 { .hook = ip_sabotage_out,
973 .owner = THIS_MODULE,
974 .pf = PF_INET,
975 .hooknum = NF_IP_FORWARD,
976 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
977 { .hook = ip_sabotage_out,
978 .owner = THIS_MODULE,
979 .pf = PF_INET6,
980 .hooknum = NF_IP6_FORWARD,
981 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
982 { .hook = ip_sabotage_out,
983 .owner = THIS_MODULE,
984 .pf = PF_INET,
985 .hooknum = NF_IP_LOCAL_OUT,
986 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
987 { .hook = ip_sabotage_out,
988 .owner = THIS_MODULE,
989 .pf = PF_INET6,
990 .hooknum = NF_IP6_LOCAL_OUT,
991 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
992 { .hook = ip_sabotage_out,
993 .owner = THIS_MODULE,
994 .pf = PF_INET,
995 .hooknum = NF_IP_POST_ROUTING,
996 .priority = NF_IP_PRI_FIRST, },
997 { .hook = ip_sabotage_out,
998 .owner = THIS_MODULE,
999 .pf = PF_INET6,
1000 .hooknum = NF_IP6_POST_ROUTING,
1001 .priority = NF_IP6_PRI_FIRST, },
1002};
1003
1004#ifdef CONFIG_SYSCTL
1005static
789bc3e5
SH		 1006int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
1007 void __user * buffer, size_t * lenp, loff_t * ppos)
1da177e4
LT		 1008{
1009 int ret;
1010
1011 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
1012
1013 if (write && *(int *)(ctl->data))
1014 *(int *)(ctl->data) = 1;
1015 return ret;
1016}
1017
1018static ctl_table brnf_table[] = {
1019 {
1020 .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
1021 .procname = "bridge-nf-call-arptables",
1022 .data = &brnf_call_arptables,
1023 .maxlen = sizeof(int),
1024 .mode = 0644,
1025 .proc_handler = &brnf_sysctl_call_tables,
1026 },
1027 {
1028 .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
1029 .procname = "bridge-nf-call-iptables",
1030 .data = &brnf_call_iptables,
1031 .maxlen = sizeof(int),
1032 .mode = 0644,
1033 .proc_handler = &brnf_sysctl_call_tables,
1034 },
1035 {
1036 .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
1037 .procname = "bridge-nf-call-ip6tables",
1038 .data = &brnf_call_ip6tables,
1039 .maxlen = sizeof(int),
1040 .mode = 0644,
1041 .proc_handler = &brnf_sysctl_call_tables,
1042 },
1043 {
1044 .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
1045 .procname = "bridge-nf-filter-vlan-tagged",
1046 .data = &brnf_filter_vlan_tagged,
1047 .maxlen = sizeof(int),
1048 .mode = 0644,
1049 .proc_handler = &brnf_sysctl_call_tables,
1050 },
1051 { .ctl_name = 0 }
1052};
1053
1054static ctl_table brnf_bridge_table[] = {
1055 {
1056 .ctl_name = NET_BRIDGE,
1057 .procname = "bridge",
1058 .mode = 0555,
1059 .child = brnf_table,
1060 },
1061 { .ctl_name = 0 }
1062};
1063
1064static ctl_table brnf_net_table[] = {
1065 {
1066 .ctl_name = CTL_NET,
1067 .procname = "net",
1068 .mode = 0555,
1069 .child = brnf_bridge_table,
1070 },
1071 { .ctl_name = 0 }
1072};
1073#endif
1074
1075int br_netfilter_init(void)
1076{
1077 int i;
1078
1079 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1080 int ret;
1081
1082 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1083 continue;
1084
1085 while (i--)
1086 nf_unregister_hook(&br_nf_ops[i]);
1087
1088 return ret;
1089 }
1090
1091#ifdef CONFIG_SYSCTL
1092 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1093 if (brnf_sysctl_header == NULL) {
789bc3e5
SH		 1094 printk(KERN_WARNING
1095 "br_netfilter: can't register to sysctl.\n");
1da177e4
LT		 1096 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1097 nf_unregister_hook(&br_nf_ops[i]);
1098 return -EFAULT;
1099 }
1100#endif
1101
1102 printk(KERN_NOTICE "Bridge firewalling registered\n");
1103
1104 return 0;
1105}
1106
1107void br_netfilter_fini(void)
1108{
1109 int i;
1110
1111 for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
1112 nf_unregister_hook(&br_nf_ops[i]);
1113#ifdef CONFIG_SYSCTL
1114 unregister_sysctl_table(brnf_sysctl_header);
1115#endif
1116}
Clone of davem's net-next-2.6 tree