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netfilter: fix some coding styles and remove moduleparam.h
[net-next-2.6.git] / net / bridge / br_netfilter.c
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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>
29#include <linux/if_arp.h>
30#include <linux/if_ether.h>
31#include <linux/if_vlan.h>
32#include <linux/if_pppox.h>
33#include <linux/ppp_defs.h>
34#include <linux/netfilter_bridge.h>
35#include <linux/netfilter_ipv4.h>
36#include <linux/netfilter_ipv6.h>
37#include <linux/netfilter_arp.h>
38#include <linux/in_route.h>
39#include <linux/inetdevice.h>
40
41#include <net/ip.h>
42#include <net/ipv6.h>
43#include <net/route.h>
44
45#include <asm/uaccess.h>
46#include "br_private.h"
47#ifdef CONFIG_SYSCTL
48#include <linux/sysctl.h>
49#endif
50
51#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
52 (skb->nf_bridge->data))->daddr.ipv4)
53#define store_orig_dstaddr(skb) (skb_origaddr(skb) = ip_hdr(skb)->daddr)
54#define dnat_took_place(skb) (skb_origaddr(skb) != ip_hdr(skb)->daddr)
55
56#ifdef CONFIG_SYSCTL
57static struct ctl_table_header *brnf_sysctl_header;
58static int brnf_call_iptables __read_mostly = 1;
59static int brnf_call_ip6tables __read_mostly = 1;
60static int brnf_call_arptables __read_mostly = 1;
61static int brnf_filter_vlan_tagged __read_mostly = 0;
62static int brnf_filter_pppoe_tagged __read_mostly = 0;
63#else
64#define brnf_filter_vlan_tagged 0
65#define brnf_filter_pppoe_tagged 0
66#endif
67
68static inline __be16 vlan_proto(const struct sk_buff *skb)
69{
70 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
71}
72
73#define IS_VLAN_IP(skb) \
74 (skb->protocol == htons(ETH_P_8021Q) && \
75 vlan_proto(skb) == htons(ETH_P_IP) && \
76 brnf_filter_vlan_tagged)
77
78#define IS_VLAN_IPV6(skb) \
79 (skb->protocol == htons(ETH_P_8021Q) && \
80 vlan_proto(skb) == htons(ETH_P_IPV6) &&\
81 brnf_filter_vlan_tagged)
82
83#define IS_VLAN_ARP(skb) \
84 (skb->protocol == htons(ETH_P_8021Q) && \
85 vlan_proto(skb) == htons(ETH_P_ARP) && \
86 brnf_filter_vlan_tagged)
87
88static inline __be16 pppoe_proto(const struct sk_buff *skb)
89{
90 return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
91 sizeof(struct pppoe_hdr)));
92}
93
94#define IS_PPPOE_IP(skb) \
95 (skb->protocol == htons(ETH_P_PPP_SES) && \
96 pppoe_proto(skb) == htons(PPP_IP) && \
97 brnf_filter_pppoe_tagged)
98
99#define IS_PPPOE_IPV6(skb) \
100 (skb->protocol == htons(ETH_P_PPP_SES) && \
101 pppoe_proto(skb) == htons(PPP_IPV6) && \
102 brnf_filter_pppoe_tagged)
103
104static void fake_update_pmtu(struct dst_entry *dst, u32 mtu)
105{
106}
107
108static struct dst_ops fake_dst_ops = {
109 .family = AF_INET,
110 .protocol = cpu_to_be16(ETH_P_IP),
111 .update_pmtu = fake_update_pmtu,
112 .entries = ATOMIC_INIT(0),
113};
114
115/*
116 * Initialize bogus route table used to keep netfilter happy.
117 * Currently, we fill in the PMTU entry because netfilter
118 * refragmentation needs it, and the rt_flags entry because
119 * ipt_REJECT needs it. Future netfilter modules might
120 * require us to fill additional fields.
121 */
122void br_netfilter_rtable_init(struct net_bridge *br)
123{
124 struct rtable *rt = &br->fake_rtable;
125
126 atomic_set(&rt->u.dst.__refcnt, 1);
127 rt->u.dst.dev = br->dev;
128 rt->u.dst.path = &rt->u.dst;
129 rt->u.dst.metrics[RTAX_MTU - 1] = 1500;
130 rt->u.dst.flags = DST_NOXFRM;
131 rt->u.dst.ops = &fake_dst_ops;
132}
133
134static inline struct rtable *bridge_parent_rtable(const struct net_device *dev)
135{
136 struct net_bridge_port *port = rcu_dereference(dev->br_port);
137
138 return port ? &port->br->fake_rtable : NULL;
139}
140
141static inline struct net_device *bridge_parent(const struct net_device *dev)
142{
143 struct net_bridge_port *port = rcu_dereference(dev->br_port);
144
145 return port ? port->br->dev : NULL;
146}
147
148static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
149{
150 skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
151 if (likely(skb->nf_bridge))
152 atomic_set(&(skb->nf_bridge->use), 1);
153
154 return skb->nf_bridge;
155}
156
157static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
158{
159 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
160
161 if (atomic_read(&nf_bridge->use) > 1) {
162 struct nf_bridge_info *tmp = nf_bridge_alloc(skb);
163
164 if (tmp) {
165 memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info));
166 atomic_set(&tmp->use, 1);
167 nf_bridge_put(nf_bridge);
168 }
169 nf_bridge = tmp;
170 }
171 return nf_bridge;
172}
173
174static inline void nf_bridge_push_encap_header(struct sk_buff *skb)
175{
176 unsigned int len = nf_bridge_encap_header_len(skb);
177
178 skb_push(skb, len);
179 skb->network_header -= len;
180}
181
182static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
183{
184 unsigned int len = nf_bridge_encap_header_len(skb);
185
186 skb_pull(skb, len);
187 skb->network_header += len;
188}
189
190static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
191{
192 unsigned int len = nf_bridge_encap_header_len(skb);
193
194 skb_pull_rcsum(skb, len);
195 skb->network_header += len;
196}
197
198static inline void nf_bridge_save_header(struct sk_buff *skb)
199{
200 int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
201
202 skb_copy_from_linear_data_offset(skb, -header_size,
203 skb->nf_bridge->data, header_size);
204}
205
206/*
207 * When forwarding bridge frames, we save a copy of the original
208 * header before processing.
209 */
210int nf_bridge_copy_header(struct sk_buff *skb)
211{
212 int err;
213 int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
214
215 err = skb_cow_head(skb, header_size);
216 if (err)
217 return err;
218
219 skb_copy_to_linear_data_offset(skb, -header_size,
220 skb->nf_bridge->data, header_size);
221 __skb_push(skb, nf_bridge_encap_header_len(skb));
222 return 0;
223}
224
225/* PF_BRIDGE/PRE_ROUTING *********************************************/
226/* Undo the changes made for ip6tables PREROUTING and continue the
227 * bridge PRE_ROUTING hook. */
228static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
229{
230 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
231 struct rtable *rt;
232
233 if (nf_bridge->mask & BRNF_PKT_TYPE) {
234 skb->pkt_type = PACKET_OTHERHOST;
235 nf_bridge->mask ^= BRNF_PKT_TYPE;
236 }
237 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
238
239 rt = bridge_parent_rtable(nf_bridge->physindev);
240 if (!rt) {
241 kfree_skb(skb);
242 return 0;
243 }
244 dst_hold(&rt->u.dst);
245 skb_dst_set(skb, &rt->u.dst);
246
247 skb->dev = nf_bridge->physindev;
248 nf_bridge_push_encap_header(skb);
249 NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
250 br_handle_frame_finish, 1);
251
252 return 0;
253}
254
255static void __br_dnat_complain(void)
256{
257 static unsigned long last_complaint;
258
259 if (jiffies - last_complaint >= 5 * HZ) {
260 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
261 "forwarding to be enabled\n");
262 last_complaint = jiffies;
263 }
264}
265
266/* This requires some explaining. If DNAT has taken place,
267 * we will need to fix up the destination Ethernet address,
268 * and this is a tricky process.
269 *
270 * There are two cases to consider:
271 * 1. The packet was DNAT'ed to a device in the same bridge
272 * port group as it was received on. We can still bridge
273 * the packet.
274 * 2. The packet was DNAT'ed to a different device, either
275 * a non-bridged device or another bridge port group.
276 * The packet will need to be routed.
277 *
278 * The correct way of distinguishing between these two cases is to
279 * call ip_route_input() and to look at skb->dst->dev, which is
280 * changed to the destination device if ip_route_input() succeeds.
281 *
282 * Let us first consider the case that ip_route_input() succeeds:
283 *
284 * If skb->dst->dev equals the logical bridge device the packet
285 * came in on, we can consider this bridging. The packet is passed
286 * through the neighbour output function to build a new destination
287 * MAC address, which will make the packet enter br_nf_local_out()
288 * not much later. In that function it is assured that the iptables
289 * FORWARD chain is traversed for the packet.
290 *
291 * Otherwise, the packet is considered to be routed and we just
292 * change the destination MAC address so that the packet will
293 * later be passed up to the IP stack to be routed. For a redirected
294 * packet, ip_route_input() will give back the localhost as output device,
295 * which differs from the bridge device.
296 *
297 * Let us now consider the case that ip_route_input() fails:
298 *
299 * This can be because the destination address is martian, in which case
300 * the packet will be dropped.
301 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
302 * will fail, while __ip_route_output_key() will return success. The source
303 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
304 * thinks we're handling a locally generated packet and won't care
305 * if IP forwarding is allowed. We send a warning message to the users's
306 * log telling her to put IP forwarding on.
307 *
308 * ip_route_input() will also fail if there is no route available.
309 * In that case we just drop the packet.
310 *
311 * --Lennert, 20020411
312 * --Bart, 20020416 (updated)
313 * --Bart, 20021007 (updated)
314 * --Bart, 20062711 (updated) */
315static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
316{
317 if (skb->pkt_type == PACKET_OTHERHOST) {
318 skb->pkt_type = PACKET_HOST;
319 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
320 }
321 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
322
323 skb->dev = bridge_parent(skb->dev);
324 if (skb->dev) {
325 struct dst_entry *dst = skb_dst(skb);
326
327 nf_bridge_pull_encap_header(skb);
328
329 if (dst->hh)
330 return neigh_hh_output(dst->hh, skb);
331 else if (dst->neighbour)
332 return dst->neighbour->output(skb);
333 }
334 kfree_skb(skb);
335 return 0;
336}
337
338static int br_nf_pre_routing_finish(struct sk_buff *skb)
339{
340 struct net_device *dev = skb->dev;
341 struct iphdr *iph = ip_hdr(skb);
342 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
343 struct rtable *rt;
344 int err;
345
346 if (nf_bridge->mask & BRNF_PKT_TYPE) {
347 skb->pkt_type = PACKET_OTHERHOST;
348 nf_bridge->mask ^= BRNF_PKT_TYPE;
349 }
350 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
351 if (dnat_took_place(skb)) {
352 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
353 struct flowi fl = {
354 .nl_u = {
355 .ip4_u = {
356 .daddr = iph->daddr,
357 .saddr = 0,
358 .tos = RT_TOS(iph->tos) },
359 },
360 .proto = 0,
361 };
362 struct in_device *in_dev = __in_dev_get_rcu(dev);
363
364 /* If err equals -EHOSTUNREACH the error is due to a
365 * martian destination or due to the fact that
366 * forwarding is disabled. For most martian packets,
367 * ip_route_output_key() will fail. It won't fail for 2 types of
368 * martian destinations: loopback destinations and destination
369 * 0.0.0.0. In both cases the packet will be dropped because the
370 * destination is the loopback device and not the bridge. */
371 if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
372 goto free_skb;
373
374 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
375 /* - Bridged-and-DNAT'ed traffic doesn't
376 * require ip_forwarding. */
377 if (((struct dst_entry *)rt)->dev == dev) {
378 skb_dst_set(skb, (struct dst_entry *)rt);
379 goto bridged_dnat;
380 }
381 /* we are sure that forwarding is disabled, so printing
382 * this message is no problem. Note that the packet could
383 * still have a martian destination address, in which case
384 * the packet could be dropped even if forwarding were enabled */
385 __br_dnat_complain();
386 dst_release((struct dst_entry *)rt);
387 }
388free_skb:
389 kfree_skb(skb);
390 return 0;
391 } else {
392 if (skb_dst(skb)->dev == dev) {
393bridged_dnat:
394 /* Tell br_nf_local_out this is a
395 * bridged frame */
396 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
397 skb->dev = nf_bridge->physindev;
398 nf_bridge_push_encap_header(skb);
399 NF_HOOK_THRESH(NFPROTO_BRIDGE,
400 NF_BR_PRE_ROUTING,
401 skb, skb->dev, NULL,
402 br_nf_pre_routing_finish_bridge,
403 1);
404 return 0;
405 }
406 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
407 skb->pkt_type = PACKET_HOST;
408 }
409 } else {
410 rt = bridge_parent_rtable(nf_bridge->physindev);
411 if (!rt) {
412 kfree_skb(skb);
413 return 0;
414 }
415 dst_hold(&rt->u.dst);
416 skb_dst_set(skb, &rt->u.dst);
417 }
418
419 skb->dev = nf_bridge->physindev;
420 nf_bridge_push_encap_header(skb);
421 NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
422 br_handle_frame_finish, 1);
423
424 return 0;
425}
426
427/* Some common code for IPv4/IPv6 */
428static struct net_device *setup_pre_routing(struct sk_buff *skb)
429{
430 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
431
432 if (skb->pkt_type == PACKET_OTHERHOST) {
433 skb->pkt_type = PACKET_HOST;
434 nf_bridge->mask |= BRNF_PKT_TYPE;
435 }
436
437 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
438 nf_bridge->physindev = skb->dev;
439 skb->dev = bridge_parent(skb->dev);
440
441 return skb->dev;
442}
443
444/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
445static int check_hbh_len(struct sk_buff *skb)
446{
447 unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1);
448 u32 pkt_len;
449 const unsigned char *nh = skb_network_header(skb);
450 int off = raw - nh;
451 int len = (raw[1] + 1) << 3;
452
453 if ((raw + len) - skb->data > skb_headlen(skb))
454 goto bad;
455
456 off += 2;
457 len -= 2;
458
459 while (len > 0) {
460 int optlen = nh[off + 1] + 2;
461
462 switch (nh[off]) {
463 case IPV6_TLV_PAD0:
464 optlen = 1;
465 break;
466
467 case IPV6_TLV_PADN:
468 break;
469
470 case IPV6_TLV_JUMBO:
471 if (nh[off + 1] != 4 || (off & 3) != 2)
472 goto bad;
473 pkt_len = ntohl(*(__be32 *) (nh + off + 2));
474 if (pkt_len <= IPV6_MAXPLEN ||
475 ipv6_hdr(skb)->payload_len)
476 goto bad;
477 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
478 goto bad;
479 if (pskb_trim_rcsum(skb,
480 pkt_len + sizeof(struct ipv6hdr)))
481 goto bad;
482 nh = skb_network_header(skb);
483 break;
484 default:
485 if (optlen > len)
486 goto bad;
487 break;
488 }
489 off += optlen;
490 len -= optlen;
491 }
492 if (len == 0)
493 return 0;
494bad:
495 return -1;
496
497}
498
499/* Replicate the checks that IPv6 does on packet reception and pass the packet
500 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
501static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
502 struct sk_buff *skb,
503 const struct net_device *in,
504 const struct net_device *out,
505 int (*okfn)(struct sk_buff *))
506{
507 struct ipv6hdr *hdr;
508 u32 pkt_len;
509
510 if (skb->len < sizeof(struct ipv6hdr))
511 goto inhdr_error;
512
513 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
514 goto inhdr_error;
515
516 hdr = ipv6_hdr(skb);
517
518 if (hdr->version != 6)
519 goto inhdr_error;
520
521 pkt_len = ntohs(hdr->payload_len);
522
523 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
524 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
525 goto inhdr_error;
526 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
527 goto inhdr_error;
528 }
529 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
530 goto inhdr_error;
531
532 nf_bridge_put(skb->nf_bridge);
533 if (!nf_bridge_alloc(skb))
534 return NF_DROP;
535 if (!setup_pre_routing(skb))
536 return NF_DROP;
537
538 NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
539 br_nf_pre_routing_finish_ipv6);
540
541 return NF_STOLEN;
542
543inhdr_error:
544 return NF_DROP;
545}
546
547/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
548 * Replicate the checks that IPv4 does on packet reception.
549 * Set skb->dev to the bridge device (i.e. parent of the
550 * receiving device) to make netfilter happy, the REDIRECT
551 * target in particular. Save the original destination IP
552 * address to be able to detect DNAT afterwards. */
553static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb,
554 const struct net_device *in,
555 const struct net_device *out,
556 int (*okfn)(struct sk_buff *))
557{
558 struct iphdr *iph;
559 __u32 len = nf_bridge_encap_header_len(skb);
560
561 if (unlikely(!pskb_may_pull(skb, len)))
562 goto out;
563
564 if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) ||
565 IS_PPPOE_IPV6(skb)) {
566#ifdef CONFIG_SYSCTL
567 if (!brnf_call_ip6tables)
568 return NF_ACCEPT;
569#endif
570 nf_bridge_pull_encap_header_rcsum(skb);
571 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
572 }
573#ifdef CONFIG_SYSCTL
574 if (!brnf_call_iptables)
575 return NF_ACCEPT;
576#endif
577
578 if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb) &&
579 !IS_PPPOE_IP(skb))
580 return NF_ACCEPT;
581
582 nf_bridge_pull_encap_header_rcsum(skb);
583
584 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
585 goto inhdr_error;
586
587 iph = ip_hdr(skb);
588 if (iph->ihl < 5 || iph->version != 4)
589 goto inhdr_error;
590
591 if (!pskb_may_pull(skb, 4 * iph->ihl))
592 goto inhdr_error;
593
594 iph = ip_hdr(skb);
595 if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
596 goto inhdr_error;
597
598 len = ntohs(iph->tot_len);
599 if (skb->len < len || len < 4 * iph->ihl)
600 goto inhdr_error;
601
602 pskb_trim_rcsum(skb, len);
603
604 nf_bridge_put(skb->nf_bridge);
605 if (!nf_bridge_alloc(skb))
606 return NF_DROP;
607 if (!setup_pre_routing(skb))
608 return NF_DROP;
609 store_orig_dstaddr(skb);
610
611 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
612 br_nf_pre_routing_finish);
613
614 return NF_STOLEN;
615
616inhdr_error:
617// IP_INC_STATS_BH(IpInHdrErrors);
618out:
619 return NF_DROP;
620}
621
622
623/* PF_BRIDGE/LOCAL_IN ************************************************/
624/* The packet is locally destined, which requires a real
625 * dst_entry, so detach the fake one. On the way up, the
626 * packet would pass through PRE_ROUTING again (which already
627 * took place when the packet entered the bridge), but we
628 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
629 * prevent this from happening. */
630static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff *skb,
631 const struct net_device *in,
632 const struct net_device *out,
633 int (*okfn)(struct sk_buff *))
634{
635 struct rtable *rt = skb_rtable(skb);
636
637 if (rt && rt == bridge_parent_rtable(in))
638 skb_dst_drop(skb);
639
640 return NF_ACCEPT;
641}
642
643/* PF_BRIDGE/FORWARD *************************************************/
644static int br_nf_forward_finish(struct sk_buff *skb)
645{
646 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
647 struct net_device *in;
648
649 if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
650 in = nf_bridge->physindev;
651 if (nf_bridge->mask & BRNF_PKT_TYPE) {
652 skb->pkt_type = PACKET_OTHERHOST;
653 nf_bridge->mask ^= BRNF_PKT_TYPE;
654 }
655 } else {
656 in = *((struct net_device **)(skb->cb));
657 }
658 nf_bridge_push_encap_header(skb);
659 NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, in,
660 skb->dev, br_forward_finish, 1);
661 return 0;
662}
663
664/* This is the 'purely bridged' case. For IP, we pass the packet to
665 * netfilter with indev and outdev set to the bridge device,
666 * but we are still able to filter on the 'real' indev/outdev
667 * because of the physdev module. For ARP, indev and outdev are the
668 * bridge ports. */
669static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb,
670 const struct net_device *in,
671 const struct net_device *out,
672 int (*okfn)(struct sk_buff *))
673{
674 struct nf_bridge_info *nf_bridge;
675 struct net_device *parent;
676 u_int8_t pf;
677
678 if (!skb->nf_bridge)
679 return NF_ACCEPT;
680
681 /* Need exclusive nf_bridge_info since we might have multiple
682 * different physoutdevs. */
683 if (!nf_bridge_unshare(skb))
684 return NF_DROP;
685
686 parent = bridge_parent(out);
687 if (!parent)
688 return NF_DROP;
689
690 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) ||
691 IS_PPPOE_IP(skb))
692 pf = PF_INET;
693 else if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) ||
694 IS_PPPOE_IPV6(skb))
695 pf = PF_INET6;
696 else
697 return NF_ACCEPT;
698
699 nf_bridge_pull_encap_header(skb);
700
701 nf_bridge = skb->nf_bridge;
702 if (skb->pkt_type == PACKET_OTHERHOST) {
703 skb->pkt_type = PACKET_HOST;
704 nf_bridge->mask |= BRNF_PKT_TYPE;
705 }
706
707 /* The physdev module checks on this */
708 nf_bridge->mask |= BRNF_BRIDGED;
709 nf_bridge->physoutdev = skb->dev;
710
711 NF_HOOK(pf, NF_INET_FORWARD, skb, bridge_parent(in), parent,
712 br_nf_forward_finish);
713
714 return NF_STOLEN;
715}
716
717static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff *skb,
718 const struct net_device *in,
719 const struct net_device *out,
720 int (*okfn)(struct sk_buff *))
721{
722 struct net_device **d = (struct net_device **)(skb->cb);
723
724#ifdef CONFIG_SYSCTL
725 if (!brnf_call_arptables)
726 return NF_ACCEPT;
727#endif
728
729 if (skb->protocol != htons(ETH_P_ARP)) {
730 if (!IS_VLAN_ARP(skb))
731 return NF_ACCEPT;
732 nf_bridge_pull_encap_header(skb);
733 }
734
735 if (arp_hdr(skb)->ar_pln != 4) {
736 if (IS_VLAN_ARP(skb))
737 nf_bridge_push_encap_header(skb);
738 return NF_ACCEPT;
739 }
740 *d = (struct net_device *)in;
741 NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
742 (struct net_device *)out, br_nf_forward_finish);
743
744 return NF_STOLEN;
745}
746
747/* PF_BRIDGE/LOCAL_OUT ***********************************************
748 *
749 * This function sees both locally originated IP packets and forwarded
750 * IP packets (in both cases the destination device is a bridge
751 * device). It also sees bridged-and-DNAT'ed packets.
752 *
753 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
754 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
755 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
756 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
757 * will be executed.
758 */
759static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff *skb,
760 const struct net_device *in,
761 const struct net_device *out,
762 int (*okfn)(struct sk_buff *))
763{
764 struct net_device *realindev;
765 struct nf_bridge_info *nf_bridge;
766
767 if (!skb->nf_bridge)
768 return NF_ACCEPT;
769
770 /* Need exclusive nf_bridge_info since we might have multiple
771 * different physoutdevs. */
772 if (!nf_bridge_unshare(skb))
773 return NF_DROP;
774
775 nf_bridge = skb->nf_bridge;
776 if (!(nf_bridge->mask & BRNF_BRIDGED_DNAT))
777 return NF_ACCEPT;
778
779 /* Bridged, take PF_BRIDGE/FORWARD.
780 * (see big note in front of br_nf_pre_routing_finish) */
781 nf_bridge->physoutdev = skb->dev;
782 realindev = nf_bridge->physindev;
783
784 if (nf_bridge->mask & BRNF_PKT_TYPE) {
785 skb->pkt_type = PACKET_OTHERHOST;
786 nf_bridge->mask ^= BRNF_PKT_TYPE;
787 }
788 nf_bridge_push_encap_header(skb);
789
790 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, realindev, skb->dev,
791 br_forward_finish);
792 return NF_STOLEN;
793}
794
795#if defined(CONFIG_NF_CONNTRACK_IPV4) || defined(CONFIG_NF_CONNTRACK_IPV4_MODULE)
796static int br_nf_dev_queue_xmit(struct sk_buff *skb)
797{
798 if (skb->nfct != NULL &&
799 (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb)) &&
800 skb->len > skb->dev->mtu &&
801 !skb_is_gso(skb))
802 return ip_fragment(skb, br_dev_queue_push_xmit);
803 else
804 return br_dev_queue_push_xmit(skb);
805}
806#else
807static int br_nf_dev_queue_xmit(struct sk_buff *skb)
808{
809 return br_dev_queue_push_xmit(skb);
810}
811#endif
812
813/* PF_BRIDGE/POST_ROUTING ********************************************/
814static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff *skb,
815 const struct net_device *in,
816 const struct net_device *out,
817 int (*okfn)(struct sk_buff *))
818{
819 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
820 struct net_device *realoutdev = bridge_parent(skb->dev);
821 u_int8_t pf;
822
823#ifdef CONFIG_NETFILTER_DEBUG
824 /* Be very paranoid. This probably won't happen anymore, but let's
825 * keep the check just to be sure... */
826 if (skb_mac_header(skb) < skb->head ||
827 skb_mac_header(skb) + ETH_HLEN > skb->data) {
828 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
829 "bad mac.raw pointer.\n");
830 goto print_error;
831 }
832#endif
833
834 if (!nf_bridge)
835 return NF_ACCEPT;
836
837 if (!(nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT)))
838 return NF_ACCEPT;
839
840 if (!realoutdev)
841 return NF_DROP;
842
843 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) ||
844 IS_PPPOE_IP(skb))
845 pf = PF_INET;
846 else if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) ||
847 IS_PPPOE_IPV6(skb))
848 pf = PF_INET6;
849 else
850 return NF_ACCEPT;
851
852#ifdef CONFIG_NETFILTER_DEBUG
853 if (skb_dst(skb) == NULL) {
854 printk(KERN_INFO "br_netfilter post_routing: skb->dst == NULL\n");
855 goto print_error;
856 }
857#endif
858
859 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
860 * about the value of skb->pkt_type. */
861 if (skb->pkt_type == PACKET_OTHERHOST) {
862 skb->pkt_type = PACKET_HOST;
863 nf_bridge->mask |= BRNF_PKT_TYPE;
864 }
865
866 nf_bridge_pull_encap_header(skb);
867 nf_bridge_save_header(skb);
868
869 NF_HOOK(pf, NF_INET_POST_ROUTING, skb, NULL, realoutdev,
870 br_nf_dev_queue_xmit);
871
872 return NF_STOLEN;
873
874#ifdef CONFIG_NETFILTER_DEBUG
875print_error:
876 if (skb->dev != NULL) {
877 printk("[%s]", skb->dev->name);
878 if (realoutdev)
879 printk("[%s]", realoutdev->name);
880 }
881 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb_mac_header(skb),
882 skb->data);
883 dump_stack();
884 return NF_ACCEPT;
885#endif
886}
887
888/* IP/SABOTAGE *****************************************************/
889/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
890 * for the second time. */
891static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff *skb,
892 const struct net_device *in,
893 const struct net_device *out,
894 int (*okfn)(struct sk_buff *))
895{
896 if (skb->nf_bridge &&
897 !(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
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[] __read_mostly = {
909 {
910 .hook = br_nf_pre_routing,
911 .owner = THIS_MODULE,
912 .pf = PF_BRIDGE,
913 .hooknum = NF_BR_PRE_ROUTING,
914 .priority = NF_BR_PRI_BRNF,
915 },
916 {
917 .hook = br_nf_local_in,
918 .owner = THIS_MODULE,
919 .pf = PF_BRIDGE,
920 .hooknum = NF_BR_LOCAL_IN,
921 .priority = NF_BR_PRI_BRNF,
922 },
923 {
924 .hook = br_nf_forward_ip,
925 .owner = THIS_MODULE,
926 .pf = PF_BRIDGE,
927 .hooknum = NF_BR_FORWARD,
928 .priority = NF_BR_PRI_BRNF - 1,
929 },
930 {
931 .hook = br_nf_forward_arp,
932 .owner = THIS_MODULE,
933 .pf = PF_BRIDGE,
934 .hooknum = NF_BR_FORWARD,
935 .priority = NF_BR_PRI_BRNF,
936 },
937 {
938 .hook = br_nf_local_out,
939 .owner = THIS_MODULE,
940 .pf = PF_BRIDGE,
941 .hooknum = NF_BR_LOCAL_OUT,
942 .priority = NF_BR_PRI_FIRST,
943 },
944 {
945 .hook = br_nf_post_routing,
946 .owner = THIS_MODULE,
947 .pf = PF_BRIDGE,
948 .hooknum = NF_BR_POST_ROUTING,
949 .priority = NF_BR_PRI_LAST,
950 },
951 {
952 .hook = ip_sabotage_in,
953 .owner = THIS_MODULE,
954 .pf = PF_INET,
955 .hooknum = NF_INET_PRE_ROUTING,
956 .priority = NF_IP_PRI_FIRST,
957 },
958 {
959 .hook = ip_sabotage_in,
960 .owner = THIS_MODULE,
961 .pf = PF_INET6,
962 .hooknum = NF_INET_PRE_ROUTING,
963 .priority = NF_IP6_PRI_FIRST,
964 },
965};
966
967#ifdef CONFIG_SYSCTL
968static
969int brnf_sysctl_call_tables(ctl_table * ctl, int write,
970 void __user * buffer, size_t * lenp, loff_t * ppos)
971{
972 int ret;
973
974 ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
975
976 if (write && *(int *)(ctl->data))
977 *(int *)(ctl->data) = 1;
978 return ret;
979}
980
981static ctl_table brnf_table[] = {
982 {
983 .procname = "bridge-nf-call-arptables",
984 .data = &brnf_call_arptables,
985 .maxlen = sizeof(int),
986 .mode = 0644,
987 .proc_handler = brnf_sysctl_call_tables,
988 },
989 {
990 .procname = "bridge-nf-call-iptables",
991 .data = &brnf_call_iptables,
992 .maxlen = sizeof(int),
993 .mode = 0644,
994 .proc_handler = brnf_sysctl_call_tables,
995 },
996 {
997 .procname = "bridge-nf-call-ip6tables",
998 .data = &brnf_call_ip6tables,
999 .maxlen = sizeof(int),
1000 .mode = 0644,
1001 .proc_handler = brnf_sysctl_call_tables,
1002 },
1003 {
1004 .procname = "bridge-nf-filter-vlan-tagged",
1005 .data = &brnf_filter_vlan_tagged,
1006 .maxlen = sizeof(int),
1007 .mode = 0644,
1008 .proc_handler = brnf_sysctl_call_tables,
1009 },
1010 {
1011 .procname = "bridge-nf-filter-pppoe-tagged",
1012 .data = &brnf_filter_pppoe_tagged,
1013 .maxlen = sizeof(int),
1014 .mode = 0644,
1015 .proc_handler = brnf_sysctl_call_tables,
1016 },
1017 { }
1018};
1019
1020static struct ctl_path brnf_path[] = {
1021 { .procname = "net", },
1022 { .procname = "bridge", },
1023 { }
1024};
1025#endif
1026
1027int __init br_netfilter_init(void)
1028{
1029 int ret;
1030
1031 ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1032 if (ret < 0)
1033 return ret;
1034#ifdef CONFIG_SYSCTL
1035 brnf_sysctl_header = register_sysctl_paths(brnf_path, brnf_table);
1036 if (brnf_sysctl_header == NULL) {
1037 printk(KERN_WARNING
1038 "br_netfilter: can't register to sysctl.\n");
1039 nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1040 return -ENOMEM;
1041 }
1042#endif
1043 printk(KERN_NOTICE "Bridge firewalling registered\n");
1044 return 0;
1045}
1046
1047void br_netfilter_fini(void)
1048{
1049 nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1050#ifdef CONFIG_SYSCTL
1051 unregister_sysctl_table(brnf_sysctl_header);
1052#endif
1053}
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