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