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[NETFILTER]: nf_conntrack: Don't try to find clashed expectation
[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 42#include <asm/uaccess.h>
1da177e4
LT		 43#include "br_private.h"
44#ifdef CONFIG_SYSCTL
45#include <linux/sysctl.h>
46#endif
47
48#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
49 (skb->nf_bridge->data))->daddr.ipv4)
50#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
51#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
52
1da177e4
LT		 53#ifdef CONFIG_SYSCTL
54static struct ctl_table_header *brnf_sysctl_header;
9c1ea148
BH		 55static int brnf_call_iptables __read_mostly = 1;
56static int brnf_call_ip6tables __read_mostly = 1;
57static int brnf_call_arptables __read_mostly = 1;
58static int brnf_filter_vlan_tagged __read_mostly = 1;
1da177e4
LT		 59#else
60#define brnf_filter_vlan_tagged 1
61#endif
62
10ea6ac8
PM		 63int brnf_deferred_hooks;
64EXPORT_SYMBOL_GPL(brnf_deferred_hooks);
65
8b42ec39
SH		 66static __be16 inline vlan_proto(const struct sk_buff *skb)
67{
68 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
69}
70
71#define IS_VLAN_IP(skb) \
72 (skb->protocol == htons(ETH_P_8021Q) && \
73 vlan_proto(skb) == htons(ETH_P_IP) && \
74 brnf_filter_vlan_tagged)
75
76#define IS_VLAN_IPV6(skb) \
77 (skb->protocol == htons(ETH_P_8021Q) && \
78 vlan_proto(skb) == htons(ETH_P_IPV6) &&\
79 brnf_filter_vlan_tagged)
80
81#define IS_VLAN_ARP(skb) \
82 (skb->protocol == htons(ETH_P_8021Q) && \
83 vlan_proto(skb) == htons(ETH_P_ARP) && \
84 brnf_filter_vlan_tagged)
1da177e4
LT		 85
86/* We need these fake structures to make netfilter happy --
87 * lots of places assume that skb->dst != NULL, which isn't
88 * all that unreasonable.
89 *
90 * Currently, we fill in the PMTU entry because netfilter
91 * refragmentation needs it, and the rt_flags entry because
92 * ipt_REJECT needs it. Future netfilter modules might
93 * require us to fill additional fields. */
94static struct net_device __fake_net_device = {
95 .hard_header_len = ETH_HLEN
96};
97
98static struct rtable __fake_rtable = {
99 .u = {
100 .dst = {
101 .__refcnt = ATOMIC_INIT(1),
102 .dev = &__fake_net_device,
103 .path = &__fake_rtable.u.dst,
104 .metrics = {[RTAX_MTU - 1] = 1500},
42cf93cd 105 .flags = DST_NOXFRM,
1da177e4
LT		 106 }
107 },
108 .rt_flags = 0,
109};
110
5dce971a
SH		 111static inline struct net_device *bridge_parent(const struct net_device *dev)
112{
113 struct net_bridge_port *port = rcu_dereference(dev->br_port);
114
115 return port ? port->br->dev : NULL;
116}
1da177e4 117
fdeabdef
SH		 118static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
119{
120 skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
121 if (likely(skb->nf_bridge))
122 atomic_set(&(skb->nf_bridge->use), 1);
123
124 return skb->nf_bridge;
125}
126
127static inline void nf_bridge_save_header(struct sk_buff *skb)
128{
07317621 129 int header_size = ETH_HLEN;
fdeabdef
SH		 130
131 if (skb->protocol == htons(ETH_P_8021Q))
07317621 132 header_size += VLAN_HLEN;
fdeabdef
SH		 133
134 memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
135}
136
07317621
SH		 137/*
138 * When forwarding bridge frames, we save a copy of the original
139 * header before processing.
140 */
141int nf_bridge_copy_header(struct sk_buff *skb)
142{
143 int err;
144 int header_size = ETH_HLEN;
145
146 if (skb->protocol == htons(ETH_P_8021Q))
147 header_size += VLAN_HLEN;
148
149 err = skb_cow(skb, header_size);
150 if (err)
151 return err;
152
153 memcpy(skb->data - header_size, skb->nf_bridge->data, header_size);
154
155 if (skb->protocol == htons(ETH_P_8021Q))
156 __skb_push(skb, VLAN_HLEN);
157 return 0;
158}
159
1da177e4
LT		 160/* PF_BRIDGE/PRE_ROUTING *********************************************/
161/* Undo the changes made for ip6tables PREROUTING and continue the
162 * bridge PRE_ROUTING hook. */
163static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
164{
165 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
166
1da177e4
LT		 167 if (nf_bridge->mask & BRNF_PKT_TYPE) {
168 skb->pkt_type = PACKET_OTHERHOST;
169 nf_bridge->mask ^= BRNF_PKT_TYPE;
170 }
171 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
172
173 skb->dst = (struct dst_entry *)&__fake_rtable;
174 dst_hold(skb->dst);
175
176 skb->dev = nf_bridge->physindev;
f8a26028 177 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 178 skb_push(skb, VLAN_HLEN);
179 skb->nh.raw -= VLAN_HLEN;
180 }
181 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
182 br_handle_frame_finish, 1);
183
184 return 0;
185}
186
187static void __br_dnat_complain(void)
188{
189 static unsigned long last_complaint;
190
191 if (jiffies - last_complaint >= 5 * HZ) {
192 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
789bc3e5 193 "forwarding to be enabled\n");
1da177e4
LT		 194 last_complaint = jiffies;
195 }
196}
197
198/* This requires some explaining. If DNAT has taken place,
199 * we will need to fix up the destination Ethernet address,
200 * and this is a tricky process.
201 *
202 * There are two cases to consider:
203 * 1. The packet was DNAT'ed to a device in the same bridge
204 * port group as it was received on. We can still bridge
205 * the packet.
206 * 2. The packet was DNAT'ed to a different device, either
207 * a non-bridged device or another bridge port group.
208 * The packet will need to be routed.
209 *
210 * The correct way of distinguishing between these two cases is to
211 * call ip_route_input() and to look at skb->dst->dev, which is
212 * changed to the destination device if ip_route_input() succeeds.
213 *
214 * Let us first consider the case that ip_route_input() succeeds:
215 *
216 * If skb->dst->dev equals the logical bridge device the packet
217 * came in on, we can consider this bridging. We then call
218 * skb->dst->output() which will make the packet enter br_nf_local_out()
219 * not much later. In that function it is assured that the iptables
220 * FORWARD chain is traversed for the packet.
221 *
222 * Otherwise, the packet is considered to be routed and we just
223 * change the destination MAC address so that the packet will
224 * later be passed up to the IP stack to be routed.
225 *
226 * Let us now consider the case that ip_route_input() fails:
227 *
228 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
229 * will fail, while __ip_route_output_key() will return success. The source
230 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
231 * thinks we're handling a locally generated packet and won't care
232 * if IP forwarding is allowed. We send a warning message to the users's
233 * log telling her to put IP forwarding on.
234 *
235 * ip_route_input() will also fail if there is no route available.
236 * In that case we just drop the packet.
237 *
238 * --Lennert, 20020411
239 * --Bart, 20020416 (updated)
240 * --Bart, 20021007 (updated) */
241static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
242{
1da177e4
LT		 243 if (skb->pkt_type == PACKET_OTHERHOST) {
244 skb->pkt_type = PACKET_HOST;
245 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
246 }
247 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
248
249 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 250 if (!skb->dev)
251 kfree_skb(skb);
252 else {
f8a26028 253 if (skb->protocol == htons(ETH_P_8021Q)) {
5dce971a
SH		 254 skb_pull(skb, VLAN_HLEN);
255 skb->nh.raw += VLAN_HLEN;
256 }
257 skb->dst->output(skb);
1da177e4 258 }
1da177e4
LT		 259 return 0;
260}
261
262static int br_nf_pre_routing_finish(struct sk_buff *skb)
263{
264 struct net_device *dev = skb->dev;
265 struct iphdr *iph = skb->nh.iph;
266 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
267
1da177e4
LT		 268 if (nf_bridge->mask & BRNF_PKT_TYPE) {
269 skb->pkt_type = PACKET_OTHERHOST;
270 nf_bridge->mask ^= BRNF_PKT_TYPE;
271 }
272 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
273
274 if (dnat_took_place(skb)) {
789bc3e5 275 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev)) {
1da177e4 276 struct rtable *rt;
789bc3e5
SH		 277 struct flowi fl = {
278 .nl_u = {
279 .ip4_u = {
280 .daddr = iph->daddr,
281 .saddr = 0,
282 .tos = RT_TOS(iph->tos) },
283 },
284 .proto = 0,
285 };
1da177e4
LT		 286
287 if (!ip_route_output_key(&rt, &fl)) {
1c011bed
BDS		 288 /* - Bridged-and-DNAT'ed traffic doesn't
289 * require ip_forwarding.
290 * - Deal with redirected traffic. */
291 if (((struct dst_entry *)rt)->dev == dev ||
292 rt->rt_type == RTN_LOCAL) {
1da177e4
LT		 293 skb->dst = (struct dst_entry *)rt;
294 goto bridged_dnat;
295 }
296 __br_dnat_complain();
297 dst_release((struct dst_entry *)rt);
298 }
299 kfree_skb(skb);
300 return 0;
301 } else {
302 if (skb->dst->dev == dev) {
303bridged_dnat:
304 /* Tell br_nf_local_out this is a
305 * bridged frame */
306 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
307 skb->dev = nf_bridge->physindev;
308 if (skb->protocol ==
f8a26028 309 htons(ETH_P_8021Q)) {
1da177e4
LT		 310 skb_push(skb, VLAN_HLEN);
311 skb->nh.raw -= VLAN_HLEN;
312 }
313 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
314 skb, skb->dev, NULL,
315 br_nf_pre_routing_finish_bridge,
316 1);
317 return 0;
318 }
789bc3e5 319 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
1da177e4
LT		 320 skb->pkt_type = PACKET_HOST;
321 }
322 } else {
323 skb->dst = (struct dst_entry *)&__fake_rtable;
324 dst_hold(skb->dst);
325 }
326
327 skb->dev = nf_bridge->physindev;
f8a26028 328 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 329 skb_push(skb, VLAN_HLEN);
330 skb->nh.raw -= VLAN_HLEN;
331 }
332 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
333 br_handle_frame_finish, 1);
334
335 return 0;
336}
337
338/* Some common code for IPv4/IPv6 */
5dce971a 339static struct net_device *setup_pre_routing(struct sk_buff *skb)
1da177e4
LT		 340{
341 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
342
343 if (skb->pkt_type == PACKET_OTHERHOST) {
344 skb->pkt_type = PACKET_HOST;
345 nf_bridge->mask |= BRNF_PKT_TYPE;
346 }
347
348 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
349 nf_bridge->physindev = skb->dev;
350 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 351
352 return skb->dev;
1da177e4
LT		 353}
354
355/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
356static int check_hbh_len(struct sk_buff *skb)
357{
789bc3e5 358 unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
1da177e4
LT		 359 u32 pkt_len;
360 int off = raw - skb->nh.raw;
789bc3e5 361 int len = (raw[1] + 1) << 3;
1da177e4
LT		 362
363 if ((raw + len) - skb->data > skb_headlen(skb))
364 goto bad;
365
366 off += 2;
367 len -= 2;
368
369 while (len > 0) {
789bc3e5 370 int optlen = skb->nh.raw[off + 1] + 2;
1da177e4
LT		 371
372 switch (skb->nh.raw[off]) {
373 case IPV6_TLV_PAD0:
374 optlen = 1;
375 break;
376
377 case IPV6_TLV_PADN:
378 break;
379
380 case IPV6_TLV_JUMBO:
789bc3e5 381 if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
1da177e4 382 goto bad;
47c183fa 383 pkt_len = ntohl(*(__be32 *) (skb->nh.raw + off + 2));
b0366486
BDS		 384 if (pkt_len <= IPV6_MAXPLEN ||
385 skb->nh.ipv6h->payload_len)
386 goto bad;
1da177e4
LT		 387 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
388 goto bad;
b0366486 389 if (pskb_trim_rcsum(skb,
789bc3e5 390 pkt_len + sizeof(struct ipv6hdr)))
b0366486 391 goto bad;
1da177e4
LT		 392 break;
393 default:
394 if (optlen > len)
395 goto bad;
396 break;
397 }
398 off += optlen;
399 len -= optlen;
400 }
401 if (len == 0)
402 return 0;
403bad:
404 return -1;
405
406}
407
408/* Replicate the checks that IPv6 does on packet reception and pass the packet
409 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
410static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
789bc3e5
SH		 411 struct sk_buff *skb,
412 const struct net_device *in,
413 const struct net_device *out,
414 int (*okfn)(struct sk_buff *))
1da177e4
LT		 415{
416 struct ipv6hdr *hdr;
417 u32 pkt_len;
1da177e4
LT		 418
419 if (skb->len < sizeof(struct ipv6hdr))
420 goto inhdr_error;
421
422 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
423 goto inhdr_error;
424
425 hdr = skb->nh.ipv6h;
426
427 if (hdr->version != 6)
428 goto inhdr_error;
429
430 pkt_len = ntohs(hdr->payload_len);
431
432 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
433 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
434 goto inhdr_error;
b38dfee3
HX		 435 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
436 goto inhdr_error;
1da177e4
LT		 437 }
438 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
789bc3e5 439 goto inhdr_error;
1da177e4 440
789bc3e5 441 nf_bridge_put(skb->nf_bridge);
fdeabdef 442 if (!nf_bridge_alloc(skb))
1da177e4 443 return NF_DROP;
5dce971a
SH		 444 if (!setup_pre_routing(skb))
445 return NF_DROP;
1da177e4
LT		 446
447 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
448 br_nf_pre_routing_finish_ipv6);
449
450 return NF_STOLEN;
451
452inhdr_error:
453 return NF_DROP;
454}
455
456/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
457 * Replicate the checks that IPv4 does on packet reception.
458 * Set skb->dev to the bridge device (i.e. parent of the
459 * receiving device) to make netfilter happy, the REDIRECT
460 * target in particular. Save the original destination IP
461 * address to be able to detect DNAT afterwards. */
462static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
ee02b3a6
SH		 463 const struct net_device *in,
464 const struct net_device *out,
465 int (*okfn)(struct sk_buff *))
1da177e4
LT		 466{
467 struct iphdr *iph;
468 __u32 len;
469 struct sk_buff *skb = *pskb;
1da177e4 470
8b42ec39 471 if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
1da177e4
LT		 472#ifdef CONFIG_SYSCTL
473 if (!brnf_call_ip6tables)
474 return NF_ACCEPT;
475#endif
476 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
477 goto out;
478
f8a26028 479 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 480 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 481 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 482 }
483 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
484 }
485#ifdef CONFIG_SYSCTL
486 if (!brnf_call_iptables)
487 return NF_ACCEPT;
488#endif
489
8b42ec39 490 if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
1da177e4
LT		 491 return NF_ACCEPT;
492
493 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
494 goto out;
495
f8a26028 496 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 497 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 498 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 499 }
500
501 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
502 goto inhdr_error;
503
504 iph = skb->nh.iph;
505 if (iph->ihl < 5 || iph->version != 4)
506 goto inhdr_error;
507
789bc3e5 508 if (!pskb_may_pull(skb, 4 * iph->ihl))
1da177e4
LT		 509 goto inhdr_error;
510
511 iph = skb->nh.iph;
789bc3e5 512 if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
1da177e4
LT		 513 goto inhdr_error;
514
515 len = ntohs(iph->tot_len);
789bc3e5 516 if (skb->len < len || len < 4 * iph->ihl)
1da177e4
LT		 517 goto inhdr_error;
518
b38dfee3 519 pskb_trim_rcsum(skb, len);
1da177e4 520
789bc3e5 521 nf_bridge_put(skb->nf_bridge);
fdeabdef 522 if (!nf_bridge_alloc(skb))
1da177e4 523 return NF_DROP;
5dce971a
SH		 524 if (!setup_pre_routing(skb))
525 return NF_DROP;
1da177e4
LT		 526 store_orig_dstaddr(skb);
527
528 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
529 br_nf_pre_routing_finish);
530
531 return NF_STOLEN;
532
533inhdr_error:
789bc3e5 534// IP_INC_STATS_BH(IpInHdrErrors);
1da177e4
LT		 535out:
536 return NF_DROP;
537}
538
539
540/* PF_BRIDGE/LOCAL_IN ************************************************/
541/* The packet is locally destined, which requires a real
542 * dst_entry, so detach the fake one. On the way up, the
543 * packet would pass through PRE_ROUTING again (which already
544 * took place when the packet entered the bridge), but we
545 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
546 * prevent this from happening. */
547static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 548 const struct net_device *in,
549 const struct net_device *out,
550 int (*okfn)(struct sk_buff *))
1da177e4
LT		 551{
552 struct sk_buff *skb = *pskb;
553
554 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
555 dst_release(skb->dst);
556 skb->dst = NULL;
557 }
558
559 return NF_ACCEPT;
560}
561
1da177e4
LT		 562/* PF_BRIDGE/FORWARD *************************************************/
563static int br_nf_forward_finish(struct sk_buff *skb)
564{
565 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
566 struct net_device *in;
1da177e4 567
8b42ec39 568 if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
1da177e4
LT		 569 in = nf_bridge->physindev;
570 if (nf_bridge->mask & BRNF_PKT_TYPE) {
571 skb->pkt_type = PACKET_OTHERHOST;
572 nf_bridge->mask ^= BRNF_PKT_TYPE;
573 }
574 } else {
575 in = *((struct net_device **)(skb->cb));
576 }
f8a26028 577 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 578 skb_push(skb, VLAN_HLEN);
579 skb->nh.raw -= VLAN_HLEN;
580 }
581 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
789bc3e5 582 skb->dev, br_forward_finish, 1);
1da177e4
LT		 583 return 0;
584}
585
586/* This is the 'purely bridged' case. For IP, we pass the packet to
587 * netfilter with indev and outdev set to the bridge device,
588 * but we are still able to filter on the 'real' indev/outdev
589 * because of the physdev module. For ARP, indev and outdev are the
590 * bridge ports. */
591static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 592 const struct net_device *in,
593 const struct net_device *out,
594 int (*okfn)(struct sk_buff *))
1da177e4
LT		 595{
596 struct sk_buff *skb = *pskb;
597 struct nf_bridge_info *nf_bridge;
5dce971a 598 struct net_device *parent;
1da177e4
LT		 599 int pf;
600
601 if (!skb->nf_bridge)
602 return NF_ACCEPT;
603
5dce971a
SH		 604 parent = bridge_parent(out);
605 if (!parent)
606 return NF_DROP;
607
8b42ec39 608 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 609 pf = PF_INET;
610 else
611 pf = PF_INET6;
612
f8a26028 613 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 614 skb_pull(*pskb, VLAN_HLEN);
615 (*pskb)->nh.raw += VLAN_HLEN;
616 }
617
1da177e4
LT		 618 nf_bridge = skb->nf_bridge;
619 if (skb->pkt_type == PACKET_OTHERHOST) {
620 skb->pkt_type = PACKET_HOST;
621 nf_bridge->mask |= BRNF_PKT_TYPE;
622 }
623
624 /* The physdev module checks on this */
625 nf_bridge->mask |= BRNF_BRIDGED;
626 nf_bridge->physoutdev = skb->dev;
627
5dce971a
SH		 628 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
629 br_nf_forward_finish);
1da177e4
LT		 630
631 return NF_STOLEN;
632}
633
634static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 635 const struct net_device *in,
636 const struct net_device *out,
637 int (*okfn)(struct sk_buff *))
1da177e4
LT		 638{
639 struct sk_buff *skb = *pskb;
1da177e4
LT		 640 struct net_device **d = (struct net_device **)(skb->cb);
641
642#ifdef CONFIG_SYSCTL
643 if (!brnf_call_arptables)
644 return NF_ACCEPT;
645#endif
646
f8a26028 647 if (skb->protocol != htons(ETH_P_ARP)) {
8b42ec39 648 if (!IS_VLAN_ARP(skb))
1da177e4
LT		 649 return NF_ACCEPT;
650 skb_pull(*pskb, VLAN_HLEN);
651 (*pskb)->nh.raw += VLAN_HLEN;
652 }
653
1da177e4 654 if (skb->nh.arph->ar_pln != 4) {
8b42ec39 655 if (IS_VLAN_ARP(skb)) {
1da177e4
LT		 656 skb_push(*pskb, VLAN_HLEN);
657 (*pskb)->nh.raw -= VLAN_HLEN;
658 }
659 return NF_ACCEPT;
660 }
661 *d = (struct net_device *)in;
662 NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
663 (struct net_device *)out, br_nf_forward_finish);
664
665 return NF_STOLEN;
666}
667
1da177e4
LT		 668/* PF_BRIDGE/LOCAL_OUT ***********************************************/
669static int br_nf_local_out_finish(struct sk_buff *skb)
670{
f8a26028 671 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 672 skb_push(skb, VLAN_HLEN);
673 skb->nh.raw -= VLAN_HLEN;
674 }
675
676 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
789bc3e5 677 br_forward_finish, NF_BR_PRI_FIRST + 1);
1da177e4
LT		 678
679 return 0;
680}
681
682/* This function sees both locally originated IP packets and forwarded
683 * IP packets (in both cases the destination device is a bridge
684 * device). It also sees bridged-and-DNAT'ed packets.
685 * To be able to filter on the physical bridge devices (with the physdev
686 * module), we steal packets destined to a bridge device away from the
687 * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
688 * when we have determined the real output device. This is done in here.
689 *
690 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
691 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
692 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
693 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
694 * will be executed.
695 * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
696 * this packet before, and so the packet was locally originated. We fake
697 * the PF_INET/LOCAL_OUT hook.
698 * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
699 * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
700 * even routed packets that didn't arrive on a bridge interface have their
701 * nf_bridge->physindev set. */
702static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 703 const struct net_device *in,
704 const struct net_device *out,
705 int (*okfn)(struct sk_buff *))
1da177e4
LT		 706{
707 struct net_device *realindev, *realoutdev;
708 struct sk_buff *skb = *pskb;
709 struct nf_bridge_info *nf_bridge;
1da177e4
LT		 710 int pf;
711
712 if (!skb->nf_bridge)
713 return NF_ACCEPT;
714
8b42ec39 715 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 716 pf = PF_INET;
717 else
718 pf = PF_INET6;
719
1da177e4
LT		 720 nf_bridge = skb->nf_bridge;
721 nf_bridge->physoutdev = skb->dev;
722 realindev = nf_bridge->physindev;
723
724 /* Bridged, take PF_BRIDGE/FORWARD.
725 * (see big note in front of br_nf_pre_routing_finish) */
726 if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
727 if (nf_bridge->mask & BRNF_PKT_TYPE) {
728 skb->pkt_type = PACKET_OTHERHOST;
729 nf_bridge->mask ^= BRNF_PKT_TYPE;
730 }
f8a26028 731 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 732 skb_push(skb, VLAN_HLEN);
733 skb->nh.raw -= VLAN_HLEN;
734 }
735
736 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
737 skb->dev, br_forward_finish);
738 goto out;
739 }
740 realoutdev = bridge_parent(skb->dev);
5dce971a
SH		 741 if (!realoutdev)
742 return NF_DROP;
1da177e4
LT		 743
744#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
745 /* iptables should match -o br0.x */
746 if (nf_bridge->netoutdev)
747 realoutdev = nf_bridge->netoutdev;
748#endif
f8a26028 749 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 750 skb_pull(skb, VLAN_HLEN);
751 (*pskb)->nh.raw += VLAN_HLEN;
752 }
753 /* IP forwarded traffic has a physindev, locally
754 * generated traffic hasn't. */
755 if (realindev != NULL) {
789bc3e5 756 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT)) {
5dce971a
SH		 757 struct net_device *parent = bridge_parent(realindev);
758 if (parent)
759 realindev = parent;
760 }
1da177e4
LT		 761
762 NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
763 realoutdev, br_nf_local_out_finish,
764 NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
765 } else {
1da177e4
LT		 766 NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
767 realoutdev, br_nf_local_out_finish,
768 NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
769 }
770
771out:
772 return NF_STOLEN;
773}
774
2e2f7aef
PM		 775static int br_nf_dev_queue_xmit(struct sk_buff *skb)
776{
777 if (skb->protocol == htons(ETH_P_IP) &&
778 skb->len > skb->dev->mtu &&
89114afd 779 !skb_is_gso(skb))
2e2f7aef
PM		 780 return ip_fragment(skb, br_dev_queue_push_xmit);
781 else
782 return br_dev_queue_push_xmit(skb);
783}
1da177e4
LT		 784
785/* PF_BRIDGE/POST_ROUTING ********************************************/
786static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 787 const struct net_device *in,
788 const struct net_device *out,
789 int (*okfn)(struct sk_buff *))
1da177e4
LT		 790{
791 struct sk_buff *skb = *pskb;
792 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
1da177e4
LT		 793 struct net_device *realoutdev = bridge_parent(skb->dev);
794 int pf;
795
796#ifdef CONFIG_NETFILTER_DEBUG
797 /* Be very paranoid. This probably won't happen anymore, but let's
798 * keep the check just to be sure... */
799 if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
800 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
8394e9b2 801 "bad mac.raw pointer.\n");
1da177e4
LT		 802 goto print_error;
803 }
804#endif
805
806 if (!nf_bridge)
807 return NF_ACCEPT;
808
5dce971a
SH		 809 if (!realoutdev)
810 return NF_DROP;
811
8b42ec39 812 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 813 pf = PF_INET;
814 else
815 pf = PF_INET6;
816
817#ifdef CONFIG_NETFILTER_DEBUG
818 if (skb->dst == NULL) {
8394e9b2 819 printk(KERN_INFO "br_netfilter post_routing: skb->dst == NULL\n");
1da177e4
LT		 820 goto print_error;
821 }
1da177e4
LT		 822#endif
823
824 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
825 * about the value of skb->pkt_type. */
826 if (skb->pkt_type == PACKET_OTHERHOST) {
827 skb->pkt_type = PACKET_HOST;
828 nf_bridge->mask |= BRNF_PKT_TYPE;
829 }
830
f8a26028 831 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 832 skb_pull(skb, VLAN_HLEN);
833 skb->nh.raw += VLAN_HLEN;
834 }
835
836 nf_bridge_save_header(skb);
837
838#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
839 if (nf_bridge->netoutdev)
840 realoutdev = nf_bridge->netoutdev;
841#endif
842 NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
2e2f7aef 843 br_nf_dev_queue_xmit);
1da177e4
LT		 844
845 return NF_STOLEN;
846
847#ifdef CONFIG_NETFILTER_DEBUG
848print_error:
849 if (skb->dev != NULL) {
850 printk("[%s]", skb->dev->name);
178a3259
SH		 851 if (realoutdev)
852 printk("[%s]", realoutdev->name);
1da177e4
LT		 853 }
854 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
789bc3e5 855 skb->data);
8394e9b2 856 dump_stack();
1da177e4
LT		 857 return NF_ACCEPT;
858#endif
859}
860
1da177e4
LT		 861/* IP/SABOTAGE *****************************************************/
862/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
863 * for the second time. */
864static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 865 const struct net_device *in,
866 const struct net_device *out,
867 int (*okfn)(struct sk_buff *))
1da177e4
LT		 868{
869 if ((*pskb)->nf_bridge &&
870 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
871 return NF_STOP;
872 }
873
874 return NF_ACCEPT;
875}
876
877/* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
878 * and PF_INET(6)/POST_ROUTING until we have done the forwarding
879 * decision in the bridge code and have determined nf_bridge->physoutdev. */
880static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 881 const struct net_device *in,
882 const struct net_device *out,
883 int (*okfn)(struct sk_buff *))
1da177e4
LT		 884{
885 struct sk_buff *skb = *pskb;
886
887 if ((out->hard_start_xmit == br_dev_xmit &&
789bc3e5 888 okfn != br_nf_forward_finish &&
2e2f7aef 889 okfn != br_nf_local_out_finish && okfn != br_nf_dev_queue_xmit)
1da177e4
LT		 890#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
891 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
789bc3e5 892 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
1da177e4
LT		 893#endif
894 ) {
895 struct nf_bridge_info *nf_bridge;
896
897 if (!skb->nf_bridge) {
898#ifdef CONFIG_SYSCTL
899 /* This code is executed while in the IP(v6) stack,
900 the version should be 4 or 6. We can't use
901 skb->protocol because that isn't set on
902 PF_INET(6)/LOCAL_OUT. */
903 struct iphdr *ip = skb->nh.iph;
904
905 if (ip->version == 4 && !brnf_call_iptables)
906 return NF_ACCEPT;
907 else if (ip->version == 6 && !brnf_call_ip6tables)
908 return NF_ACCEPT;
10ea6ac8
PM		 909 else if (!brnf_deferred_hooks)
910 return NF_ACCEPT;
1da177e4
LT		 911#endif
912 if (hook == NF_IP_POST_ROUTING)
913 return NF_ACCEPT;
914 if (!nf_bridge_alloc(skb))
915 return NF_DROP;
916 }
917
918 nf_bridge = skb->nf_bridge;
919
920 /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
921 * will need the indev then. For a brouter, the real indev
922 * can be a bridge port, so we make sure br_nf_local_out()
923 * doesn't use the bridge parent of the indev by using
924 * the BRNF_DONT_TAKE_PARENT mask. */
925 if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
9666dae5 926 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
1da177e4
LT		 927 nf_bridge->physindev = (struct net_device *)in;
928 }
929#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
930 /* the iptables outdev is br0.x, not br0 */
931 if (out->priv_flags & IFF_802_1Q_VLAN)
932 nf_bridge->netoutdev = (struct net_device *)out;
933#endif
934 return NF_STOP;
935 }
936
937 return NF_ACCEPT;
938}
939
940/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
941 * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
942 * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
943 * ip_refrag() can return NF_STOLEN. */
944static struct nf_hook_ops br_nf_ops[] = {
945 { .hook = br_nf_pre_routing,
946 .owner = THIS_MODULE,
947 .pf = PF_BRIDGE,
948 .hooknum = NF_BR_PRE_ROUTING,
949 .priority = NF_BR_PRI_BRNF, },
950 { .hook = br_nf_local_in,
951 .owner = THIS_MODULE,
952 .pf = PF_BRIDGE,
953 .hooknum = NF_BR_LOCAL_IN,
954 .priority = NF_BR_PRI_BRNF, },
955 { .hook = br_nf_forward_ip,
956 .owner = THIS_MODULE,
957 .pf = PF_BRIDGE,
958 .hooknum = NF_BR_FORWARD,
959 .priority = NF_BR_PRI_BRNF - 1, },
960 { .hook = br_nf_forward_arp,
961 .owner = THIS_MODULE,
962 .pf = PF_BRIDGE,
963 .hooknum = NF_BR_FORWARD,
964 .priority = NF_BR_PRI_BRNF, },
965 { .hook = br_nf_local_out,
966 .owner = THIS_MODULE,
967 .pf = PF_BRIDGE,
968 .hooknum = NF_BR_LOCAL_OUT,
969 .priority = NF_BR_PRI_FIRST, },
970 { .hook = br_nf_post_routing,
971 .owner = THIS_MODULE,
972 .pf = PF_BRIDGE,
973 .hooknum = NF_BR_POST_ROUTING,
974 .priority = NF_BR_PRI_LAST, },
975 { .hook = ip_sabotage_in,
976 .owner = THIS_MODULE,
977 .pf = PF_INET,
978 .hooknum = NF_IP_PRE_ROUTING,
979 .priority = NF_IP_PRI_FIRST, },
980 { .hook = ip_sabotage_in,
981 .owner = THIS_MODULE,
982 .pf = PF_INET6,
983 .hooknum = NF_IP6_PRE_ROUTING,
984 .priority = NF_IP6_PRI_FIRST, },
985 { .hook = ip_sabotage_out,
986 .owner = THIS_MODULE,
987 .pf = PF_INET,
988 .hooknum = NF_IP_FORWARD,
989 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
990 { .hook = ip_sabotage_out,
991 .owner = THIS_MODULE,
992 .pf = PF_INET6,
993 .hooknum = NF_IP6_FORWARD,
994 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
995 { .hook = ip_sabotage_out,
996 .owner = THIS_MODULE,
997 .pf = PF_INET,
998 .hooknum = NF_IP_LOCAL_OUT,
999 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
1000 { .hook = ip_sabotage_out,
1001 .owner = THIS_MODULE,
1002 .pf = PF_INET6,
1003 .hooknum = NF_IP6_LOCAL_OUT,
1004 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
1005 { .hook = ip_sabotage_out,
1006 .owner = THIS_MODULE,
1007 .pf = PF_INET,
1008 .hooknum = NF_IP_POST_ROUTING,
1009 .priority = NF_IP_PRI_FIRST, },
1010 { .hook = ip_sabotage_out,
1011 .owner = THIS_MODULE,
1012 .pf = PF_INET6,
1013 .hooknum = NF_IP6_POST_ROUTING,
1014 .priority = NF_IP6_PRI_FIRST, },
1015};
1016
1017#ifdef CONFIG_SYSCTL
1018static
789bc3e5
SH		 1019int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
1020 void __user * buffer, size_t * lenp, loff_t * ppos)
1da177e4
LT		 1021{
1022 int ret;
1023
1024 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
1025
1026 if (write && *(int *)(ctl->data))
1027 *(int *)(ctl->data) = 1;
1028 return ret;
1029}
1030
1031static ctl_table brnf_table[] = {
1032 {
1033 .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
1034 .procname = "bridge-nf-call-arptables",
1035 .data = &brnf_call_arptables,
1036 .maxlen = sizeof(int),
1037 .mode = 0644,
1038 .proc_handler = &brnf_sysctl_call_tables,
1039 },
1040 {
1041 .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
1042 .procname = "bridge-nf-call-iptables",
1043 .data = &brnf_call_iptables,
1044 .maxlen = sizeof(int),
1045 .mode = 0644,
1046 .proc_handler = &brnf_sysctl_call_tables,
1047 },
1048 {
1049 .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
1050 .procname = "bridge-nf-call-ip6tables",
1051 .data = &brnf_call_ip6tables,
1052 .maxlen = sizeof(int),
1053 .mode = 0644,
1054 .proc_handler = &brnf_sysctl_call_tables,
1055 },
1056 {
1057 .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
1058 .procname = "bridge-nf-filter-vlan-tagged",
1059 .data = &brnf_filter_vlan_tagged,
1060 .maxlen = sizeof(int),
1061 .mode = 0644,
1062 .proc_handler = &brnf_sysctl_call_tables,
1063 },
1064 { .ctl_name = 0 }
1065};
1066
1067static ctl_table brnf_bridge_table[] = {
1068 {
1069 .ctl_name = NET_BRIDGE,
1070 .procname = "bridge",
1071 .mode = 0555,
1072 .child = brnf_table,
1073 },
1074 { .ctl_name = 0 }
1075};
1076
1077static ctl_table brnf_net_table[] = {
1078 {
1079 .ctl_name = CTL_NET,
1080 .procname = "net",
1081 .mode = 0555,
1082 .child = brnf_bridge_table,
1083 },
1084 { .ctl_name = 0 }
1085};
1086#endif
1087
1088int br_netfilter_init(void)
1089{
1090 int i;
1091
1092 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1093 int ret;
1094
1095 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1096 continue;
1097
1098 while (i--)
1099 nf_unregister_hook(&br_nf_ops[i]);
1100
1101 return ret;
1102 }
1103
1104#ifdef CONFIG_SYSCTL
1105 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1106 if (brnf_sysctl_header == NULL) {
789bc3e5
SH		 1107 printk(KERN_WARNING
1108 "br_netfilter: can't register to sysctl.\n");
1da177e4
LT		 1109 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1110 nf_unregister_hook(&br_nf_ops[i]);
1111 return -EFAULT;
1112 }
1113#endif
1114
1115 printk(KERN_NOTICE "Bridge firewalling registered\n");
1116
1117 return 0;
1118}
1119
1120void br_netfilter_fini(void)
1121{
1122 int i;
1123
1124 for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
1125 nf_unregister_hook(&br_nf_ops[i]);
1126#ifdef CONFIG_SYSCTL
1127 unregister_sysctl_table(brnf_sysctl_header);
1128#endif
1129}
Clone of davem's net-next-2.6 tree