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[BRIDGE]: optimize frame pass up
[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
64#define IS_VLAN_IP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
65 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IP) && \
66 brnf_filter_vlan_tagged)
67#define IS_VLAN_IPV6 (skb->protocol == __constant_htons(ETH_P_8021Q) && \
68 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IPV6) && \
69 brnf_filter_vlan_tagged)
70#define IS_VLAN_ARP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
71 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_ARP) && \
72 brnf_filter_vlan_tagged)
73
74/* We need these fake structures to make netfilter happy --
75 * lots of places assume that skb->dst != NULL, which isn't
76 * all that unreasonable.
77 *
78 * Currently, we fill in the PMTU entry because netfilter
79 * refragmentation needs it, and the rt_flags entry because
80 * ipt_REJECT needs it. Future netfilter modules might
81 * require us to fill additional fields. */
82static struct net_device __fake_net_device = {
83 .hard_header_len = ETH_HLEN
84};
85
86static struct rtable __fake_rtable = {
87 .u = {
88 .dst = {
89 .__refcnt = ATOMIC_INIT(1),
90 .dev = &__fake_net_device,
91 .path = &__fake_rtable.u.dst,
92 .metrics = {[RTAX_MTU - 1] = 1500},
42cf93cd 93 .flags = DST_NOXFRM,
1da177e4
LT		 94 }
95 },
96 .rt_flags = 0,
97};
98
5dce971a
SH		 99static inline struct net_device *bridge_parent(const struct net_device *dev)
100{
101 struct net_bridge_port *port = rcu_dereference(dev->br_port);
102
103 return port ? port->br->dev : NULL;
104}
1da177e4
LT		 105
106/* PF_BRIDGE/PRE_ROUTING *********************************************/
107/* Undo the changes made for ip6tables PREROUTING and continue the
108 * bridge PRE_ROUTING hook. */
109static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
110{
111 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
112
1da177e4
LT		 113 if (nf_bridge->mask & BRNF_PKT_TYPE) {
114 skb->pkt_type = PACKET_OTHERHOST;
115 nf_bridge->mask ^= BRNF_PKT_TYPE;
116 }
117 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
118
119 skb->dst = (struct dst_entry *)&__fake_rtable;
120 dst_hold(skb->dst);
121
122 skb->dev = nf_bridge->physindev;
123 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
124 skb_push(skb, VLAN_HLEN);
125 skb->nh.raw -= VLAN_HLEN;
126 }
127 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
128 br_handle_frame_finish, 1);
129
130 return 0;
131}
132
133static void __br_dnat_complain(void)
134{
135 static unsigned long last_complaint;
136
137 if (jiffies - last_complaint >= 5 * HZ) {
138 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
139 "forwarding to be enabled\n");
140 last_complaint = jiffies;
141 }
142}
143
144/* This requires some explaining. If DNAT has taken place,
145 * we will need to fix up the destination Ethernet address,
146 * and this is a tricky process.
147 *
148 * There are two cases to consider:
149 * 1. The packet was DNAT'ed to a device in the same bridge
150 * port group as it was received on. We can still bridge
151 * the packet.
152 * 2. The packet was DNAT'ed to a different device, either
153 * a non-bridged device or another bridge port group.
154 * The packet will need to be routed.
155 *
156 * The correct way of distinguishing between these two cases is to
157 * call ip_route_input() and to look at skb->dst->dev, which is
158 * changed to the destination device if ip_route_input() succeeds.
159 *
160 * Let us first consider the case that ip_route_input() succeeds:
161 *
162 * If skb->dst->dev equals the logical bridge device the packet
163 * came in on, we can consider this bridging. We then call
164 * skb->dst->output() which will make the packet enter br_nf_local_out()
165 * not much later. In that function it is assured that the iptables
166 * FORWARD chain is traversed for the packet.
167 *
168 * Otherwise, the packet is considered to be routed and we just
169 * change the destination MAC address so that the packet will
170 * later be passed up to the IP stack to be routed.
171 *
172 * Let us now consider the case that ip_route_input() fails:
173 *
174 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
175 * will fail, while __ip_route_output_key() will return success. The source
176 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
177 * thinks we're handling a locally generated packet and won't care
178 * if IP forwarding is allowed. We send a warning message to the users's
179 * log telling her to put IP forwarding on.
180 *
181 * ip_route_input() will also fail if there is no route available.
182 * In that case we just drop the packet.
183 *
184 * --Lennert, 20020411
185 * --Bart, 20020416 (updated)
186 * --Bart, 20021007 (updated) */
187static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
188{
1da177e4
LT		 189 if (skb->pkt_type == PACKET_OTHERHOST) {
190 skb->pkt_type = PACKET_HOST;
191 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
192 }
193 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
194
195 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 196 if (!skb->dev)
197 kfree_skb(skb);
198 else {
199 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
200 skb_pull(skb, VLAN_HLEN);
201 skb->nh.raw += VLAN_HLEN;
202 }
203 skb->dst->output(skb);
1da177e4 204 }
1da177e4
LT		 205 return 0;
206}
207
208static int br_nf_pre_routing_finish(struct sk_buff *skb)
209{
210 struct net_device *dev = skb->dev;
211 struct iphdr *iph = skb->nh.iph;
212 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
213
1da177e4
LT		 214 if (nf_bridge->mask & BRNF_PKT_TYPE) {
215 skb->pkt_type = PACKET_OTHERHOST;
216 nf_bridge->mask ^= BRNF_PKT_TYPE;
217 }
218 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
219
220 if (dnat_took_place(skb)) {
221 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
222 dev)) {
223 struct rtable *rt;
224 struct flowi fl = { .nl_u =
225 { .ip4_u = { .daddr = iph->daddr, .saddr = 0 ,
226 .tos = RT_TOS(iph->tos)} }, .proto = 0};
227
228 if (!ip_route_output_key(&rt, &fl)) {
1c011bed
BDS		 229 /* - Bridged-and-DNAT'ed traffic doesn't
230 * require ip_forwarding.
231 * - Deal with redirected traffic. */
232 if (((struct dst_entry *)rt)->dev == dev ||
233 rt->rt_type == RTN_LOCAL) {
1da177e4
LT		 234 skb->dst = (struct dst_entry *)rt;
235 goto bridged_dnat;
236 }
237 __br_dnat_complain();
238 dst_release((struct dst_entry *)rt);
239 }
240 kfree_skb(skb);
241 return 0;
242 } else {
243 if (skb->dst->dev == dev) {
244bridged_dnat:
245 /* Tell br_nf_local_out this is a
246 * bridged frame */
247 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
248 skb->dev = nf_bridge->physindev;
249 if (skb->protocol ==
250 __constant_htons(ETH_P_8021Q)) {
251 skb_push(skb, VLAN_HLEN);
252 skb->nh.raw -= VLAN_HLEN;
253 }
254 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
255 skb, skb->dev, NULL,
256 br_nf_pre_routing_finish_bridge,
257 1);
258 return 0;
259 }
260 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr,
261 ETH_ALEN);
262 skb->pkt_type = PACKET_HOST;
263 }
264 } else {
265 skb->dst = (struct dst_entry *)&__fake_rtable;
266 dst_hold(skb->dst);
267 }
268
269 skb->dev = nf_bridge->physindev;
270 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
271 skb_push(skb, VLAN_HLEN);
272 skb->nh.raw -= VLAN_HLEN;
273 }
274 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
275 br_handle_frame_finish, 1);
276
277 return 0;
278}
279
280/* Some common code for IPv4/IPv6 */
5dce971a 281static struct net_device *setup_pre_routing(struct sk_buff *skb)
1da177e4
LT		 282{
283 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
284
285 if (skb->pkt_type == PACKET_OTHERHOST) {
286 skb->pkt_type = PACKET_HOST;
287 nf_bridge->mask |= BRNF_PKT_TYPE;
288 }
289
290 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
291 nf_bridge->physindev = skb->dev;
292 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 293
294 return skb->dev;
1da177e4
LT		 295}
296
297/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
298static int check_hbh_len(struct sk_buff *skb)
299{
300 unsigned char *raw = (u8*)(skb->nh.ipv6h+1);
301 u32 pkt_len;
302 int off = raw - skb->nh.raw;
303 int len = (raw[1]+1)<<3;
304
305 if ((raw + len) - skb->data > skb_headlen(skb))
306 goto bad;
307
308 off += 2;
309 len -= 2;
310
311 while (len > 0) {
b0366486 312 int optlen = skb->nh.raw[off+1]+2;
1da177e4
LT		 313
314 switch (skb->nh.raw[off]) {
315 case IPV6_TLV_PAD0:
316 optlen = 1;
317 break;
318
319 case IPV6_TLV_PADN:
320 break;
321
322 case IPV6_TLV_JUMBO:
323 if (skb->nh.raw[off+1] != 4 || (off&3) != 2)
324 goto bad;
1da177e4 325 pkt_len = ntohl(*(u32*)(skb->nh.raw+off+2));
b0366486
BDS		 326 if (pkt_len <= IPV6_MAXPLEN ||
327 skb->nh.ipv6h->payload_len)
328 goto bad;
1da177e4
LT		 329 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
330 goto bad;
b0366486
BDS		 331 if (pskb_trim_rcsum(skb,
332 pkt_len+sizeof(struct ipv6hdr)))
333 goto bad;
1da177e4
LT		 334 break;
335 default:
336 if (optlen > len)
337 goto bad;
338 break;
339 }
340 off += optlen;
341 len -= optlen;
342 }
343 if (len == 0)
344 return 0;
345bad:
346 return -1;
347
348}
349
350/* Replicate the checks that IPv6 does on packet reception and pass the packet
351 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
352static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
353 struct sk_buff *skb, const struct net_device *in,
354 const struct net_device *out, int (*okfn)(struct sk_buff *))
355{
356 struct ipv6hdr *hdr;
357 u32 pkt_len;
358 struct nf_bridge_info *nf_bridge;
359
360 if (skb->len < sizeof(struct ipv6hdr))
361 goto inhdr_error;
362
363 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
364 goto inhdr_error;
365
366 hdr = skb->nh.ipv6h;
367
368 if (hdr->version != 6)
369 goto inhdr_error;
370
371 pkt_len = ntohs(hdr->payload_len);
372
373 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
374 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
375 goto inhdr_error;
376 if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
377 if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr)))
378 goto inhdr_error;
379 if (skb->ip_summed == CHECKSUM_HW)
380 skb->ip_summed = CHECKSUM_NONE;
381 }
382 }
383 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
384 goto inhdr_error;
385
79cac2a2 386 nf_bridge_put(skb->nf_bridge);
1da177e4
LT		 387 if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
388 return NF_DROP;
5dce971a
SH		 389 if (!setup_pre_routing(skb))
390 return NF_DROP;
1da177e4
LT		 391
392 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
393 br_nf_pre_routing_finish_ipv6);
394
395 return NF_STOLEN;
396
397inhdr_error:
398 return NF_DROP;
399}
400
401/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
402 * Replicate the checks that IPv4 does on packet reception.
403 * Set skb->dev to the bridge device (i.e. parent of the
404 * receiving device) to make netfilter happy, the REDIRECT
405 * target in particular. Save the original destination IP
406 * address to be able to detect DNAT afterwards. */
407static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
ee02b3a6
SH		 408 const struct net_device *in,
409 const struct net_device *out,
410 int (*okfn)(struct sk_buff *))
1da177e4
LT		 411{
412 struct iphdr *iph;
413 __u32 len;
414 struct sk_buff *skb = *pskb;
415 struct nf_bridge_info *nf_bridge;
416 struct vlan_ethhdr *hdr = vlan_eth_hdr(*pskb);
417
418 if (skb->protocol == __constant_htons(ETH_P_IPV6) || IS_VLAN_IPV6) {
419#ifdef CONFIG_SYSCTL
420 if (!brnf_call_ip6tables)
421 return NF_ACCEPT;
422#endif
423 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
424 goto out;
425
426 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
cbb042f9 427 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 428 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 429 }
430 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
431 }
432#ifdef CONFIG_SYSCTL
433 if (!brnf_call_iptables)
434 return NF_ACCEPT;
435#endif
436
437 if (skb->protocol != __constant_htons(ETH_P_IP) && !IS_VLAN_IP)
438 return NF_ACCEPT;
439
440 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
441 goto out;
442
443 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
cbb042f9 444 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 445 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 446 }
447
448 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
449 goto inhdr_error;
450
451 iph = skb->nh.iph;
452 if (iph->ihl < 5 || iph->version != 4)
453 goto inhdr_error;
454
455 if (!pskb_may_pull(skb, 4*iph->ihl))
456 goto inhdr_error;
457
458 iph = skb->nh.iph;
459 if (ip_fast_csum((__u8 *)iph, iph->ihl) != 0)
460 goto inhdr_error;
461
462 len = ntohs(iph->tot_len);
463 if (skb->len < len || len < 4*iph->ihl)
464 goto inhdr_error;
465
466 if (skb->len > len) {
467 __pskb_trim(skb, len);
468 if (skb->ip_summed == CHECKSUM_HW)
469 skb->ip_summed = CHECKSUM_NONE;
470 }
471
79cac2a2 472 nf_bridge_put(skb->nf_bridge);
1da177e4
LT		 473 if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
474 return NF_DROP;
5dce971a
SH		 475 if (!setup_pre_routing(skb))
476 return NF_DROP;
1da177e4
LT		 477 store_orig_dstaddr(skb);
478
479 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
480 br_nf_pre_routing_finish);
481
482 return NF_STOLEN;
483
484inhdr_error:
485// IP_INC_STATS_BH(IpInHdrErrors);
486out:
487 return NF_DROP;
488}
489
490
491/* PF_BRIDGE/LOCAL_IN ************************************************/
492/* The packet is locally destined, which requires a real
493 * dst_entry, so detach the fake one. On the way up, the
494 * packet would pass through PRE_ROUTING again (which already
495 * took place when the packet entered the bridge), but we
496 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
497 * prevent this from happening. */
498static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
499 const struct net_device *in, const struct net_device *out,
500 int (*okfn)(struct sk_buff *))
501{
502 struct sk_buff *skb = *pskb;
503
504 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
505 dst_release(skb->dst);
506 skb->dst = NULL;
507 }
508
509 return NF_ACCEPT;
510}
511
512
513/* PF_BRIDGE/FORWARD *************************************************/
514static int br_nf_forward_finish(struct sk_buff *skb)
515{
516 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
517 struct net_device *in;
518 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
519
1da177e4
LT		 520 if (skb->protocol != __constant_htons(ETH_P_ARP) && !IS_VLAN_ARP) {
521 in = nf_bridge->physindev;
522 if (nf_bridge->mask & BRNF_PKT_TYPE) {
523 skb->pkt_type = PACKET_OTHERHOST;
524 nf_bridge->mask ^= BRNF_PKT_TYPE;
525 }
526 } else {
527 in = *((struct net_device **)(skb->cb));
528 }
529 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
530 skb_push(skb, VLAN_HLEN);
531 skb->nh.raw -= VLAN_HLEN;
532 }
533 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
534 skb->dev, br_forward_finish, 1);
535 return 0;
536}
537
538/* This is the 'purely bridged' case. For IP, we pass the packet to
539 * netfilter with indev and outdev set to the bridge device,
540 * but we are still able to filter on the 'real' indev/outdev
541 * because of the physdev module. For ARP, indev and outdev are the
542 * bridge ports. */
543static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
544 const struct net_device *in, const struct net_device *out,
545 int (*okfn)(struct sk_buff *))
546{
547 struct sk_buff *skb = *pskb;
548 struct nf_bridge_info *nf_bridge;
549 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
5dce971a 550 struct net_device *parent;
1da177e4
LT		 551 int pf;
552
553 if (!skb->nf_bridge)
554 return NF_ACCEPT;
555
5dce971a
SH		 556 parent = bridge_parent(out);
557 if (!parent)
558 return NF_DROP;
559
1da177e4
LT		 560 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
561 pf = PF_INET;
562 else
563 pf = PF_INET6;
564
565 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
566 skb_pull(*pskb, VLAN_HLEN);
567 (*pskb)->nh.raw += VLAN_HLEN;
568 }
569
1da177e4
LT		 570 nf_bridge = skb->nf_bridge;
571 if (skb->pkt_type == PACKET_OTHERHOST) {
572 skb->pkt_type = PACKET_HOST;
573 nf_bridge->mask |= BRNF_PKT_TYPE;
574 }
575
576 /* The physdev module checks on this */
577 nf_bridge->mask |= BRNF_BRIDGED;
578 nf_bridge->physoutdev = skb->dev;
579
5dce971a
SH		 580 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
581 br_nf_forward_finish);
1da177e4
LT		 582
583 return NF_STOLEN;
584}
585
586static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
587 const struct net_device *in, const struct net_device *out,
588 int (*okfn)(struct sk_buff *))
589{
590 struct sk_buff *skb = *pskb;
591 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
592 struct net_device **d = (struct net_device **)(skb->cb);
593
594#ifdef CONFIG_SYSCTL
595 if (!brnf_call_arptables)
596 return NF_ACCEPT;
597#endif
598
599 if (skb->protocol != __constant_htons(ETH_P_ARP)) {
600 if (!IS_VLAN_ARP)
601 return NF_ACCEPT;
602 skb_pull(*pskb, VLAN_HLEN);
603 (*pskb)->nh.raw += VLAN_HLEN;
604 }
605
1da177e4
LT		 606 if (skb->nh.arph->ar_pln != 4) {
607 if (IS_VLAN_ARP) {
608 skb_push(*pskb, VLAN_HLEN);
609 (*pskb)->nh.raw -= VLAN_HLEN;
610 }
611 return NF_ACCEPT;
612 }
613 *d = (struct net_device *)in;
614 NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
615 (struct net_device *)out, br_nf_forward_finish);
616
617 return NF_STOLEN;
618}
619
620
621/* PF_BRIDGE/LOCAL_OUT ***********************************************/
622static int br_nf_local_out_finish(struct sk_buff *skb)
623{
1da177e4
LT		 624 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
625 skb_push(skb, VLAN_HLEN);
626 skb->nh.raw -= VLAN_HLEN;
627 }
628
629 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
630 br_forward_finish, NF_BR_PRI_FIRST + 1);
631
632 return 0;
633}
634
635/* This function sees both locally originated IP packets and forwarded
636 * IP packets (in both cases the destination device is a bridge
637 * device). It also sees bridged-and-DNAT'ed packets.
638 * To be able to filter on the physical bridge devices (with the physdev
639 * module), we steal packets destined to a bridge device away from the
640 * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
641 * when we have determined the real output device. This is done in here.
642 *
643 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
644 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
645 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
646 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
647 * will be executed.
648 * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
649 * this packet before, and so the packet was locally originated. We fake
650 * the PF_INET/LOCAL_OUT hook.
651 * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
652 * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
653 * even routed packets that didn't arrive on a bridge interface have their
654 * nf_bridge->physindev set. */
655static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
656 const struct net_device *in, const struct net_device *out,
657 int (*okfn)(struct sk_buff *))
658{
659 struct net_device *realindev, *realoutdev;
660 struct sk_buff *skb = *pskb;
661 struct nf_bridge_info *nf_bridge;
662 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
663 int pf;
664
665 if (!skb->nf_bridge)
666 return NF_ACCEPT;
667
668 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
669 pf = PF_INET;
670 else
671 pf = PF_INET6;
672
673#ifdef CONFIG_NETFILTER_DEBUG
674 /* Sometimes we get packets with NULL ->dst here (for example,
675 * running a dhcp client daemon triggers this). This should now
676 * be fixed, but let's keep the check around. */
677 if (skb->dst == NULL) {
678 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
679 return NF_ACCEPT;
680 }
681#endif
682
683 nf_bridge = skb->nf_bridge;
684 nf_bridge->physoutdev = skb->dev;
685 realindev = nf_bridge->physindev;
686
687 /* Bridged, take PF_BRIDGE/FORWARD.
688 * (see big note in front of br_nf_pre_routing_finish) */
689 if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
690 if (nf_bridge->mask & BRNF_PKT_TYPE) {
691 skb->pkt_type = PACKET_OTHERHOST;
692 nf_bridge->mask ^= BRNF_PKT_TYPE;
693 }
694 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
695 skb_push(skb, VLAN_HLEN);
696 skb->nh.raw -= VLAN_HLEN;
697 }
698
699 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
700 skb->dev, br_forward_finish);
701 goto out;
702 }
703 realoutdev = bridge_parent(skb->dev);
5dce971a
SH		 704 if (!realoutdev)
705 return NF_DROP;
1da177e4
LT		 706
707#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
708 /* iptables should match -o br0.x */
709 if (nf_bridge->netoutdev)
710 realoutdev = nf_bridge->netoutdev;
711#endif
712 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
713 skb_pull(skb, VLAN_HLEN);
714 (*pskb)->nh.raw += VLAN_HLEN;
715 }
716 /* IP forwarded traffic has a physindev, locally
717 * generated traffic hasn't. */
718 if (realindev != NULL) {
5dce971a
SH		 719 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT) ) {
720 struct net_device *parent = bridge_parent(realindev);
721 if (parent)
722 realindev = parent;
723 }
1da177e4
LT		 724
725 NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
726 realoutdev, br_nf_local_out_finish,
727 NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
728 } else {
1da177e4
LT		 729 NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
730 realoutdev, br_nf_local_out_finish,
731 NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
732 }
733
734out:
735 return NF_STOLEN;
736}
737
738
739/* PF_BRIDGE/POST_ROUTING ********************************************/
740static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
741 const struct net_device *in, const struct net_device *out,
742 int (*okfn)(struct sk_buff *))
743{
744 struct sk_buff *skb = *pskb;
745 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
746 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
747 struct net_device *realoutdev = bridge_parent(skb->dev);
748 int pf;
749
750#ifdef CONFIG_NETFILTER_DEBUG
751 /* Be very paranoid. This probably won't happen anymore, but let's
752 * keep the check just to be sure... */
753 if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
754 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
755 "bad mac.raw pointer.");
756 goto print_error;
757 }
758#endif
759
760 if (!nf_bridge)
761 return NF_ACCEPT;
762
5dce971a
SH		 763 if (!realoutdev)
764 return NF_DROP;
765
1da177e4
LT		 766 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
767 pf = PF_INET;
768 else
769 pf = PF_INET6;
770
771#ifdef CONFIG_NETFILTER_DEBUG
772 if (skb->dst == NULL) {
773 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
774 goto print_error;
775 }
1da177e4
LT		 776#endif
777
778 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
779 * about the value of skb->pkt_type. */
780 if (skb->pkt_type == PACKET_OTHERHOST) {
781 skb->pkt_type = PACKET_HOST;
782 nf_bridge->mask |= BRNF_PKT_TYPE;
783 }
784
785 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
786 skb_pull(skb, VLAN_HLEN);
787 skb->nh.raw += VLAN_HLEN;
788 }
789
790 nf_bridge_save_header(skb);
791
792#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
793 if (nf_bridge->netoutdev)
794 realoutdev = nf_bridge->netoutdev;
795#endif
796 NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
797 br_dev_queue_push_xmit);
798
799 return NF_STOLEN;
800
801#ifdef CONFIG_NETFILTER_DEBUG
802print_error:
803 if (skb->dev != NULL) {
804 printk("[%s]", skb->dev->name);
178a3259
SH		 805 if (realoutdev)
806 printk("[%s]", realoutdev->name);
1da177e4
LT		 807 }
808 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
809 skb->data);
810 return NF_ACCEPT;
811#endif
812}
813
814
815/* IP/SABOTAGE *****************************************************/
816/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
817 * for the second time. */
818static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
819 const struct net_device *in, const struct net_device *out,
820 int (*okfn)(struct sk_buff *))
821{
822 if ((*pskb)->nf_bridge &&
823 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
824 return NF_STOP;
825 }
826
827 return NF_ACCEPT;
828}
829
830/* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
831 * and PF_INET(6)/POST_ROUTING until we have done the forwarding
832 * decision in the bridge code and have determined nf_bridge->physoutdev. */
833static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
834 const struct net_device *in, const struct net_device *out,
835 int (*okfn)(struct sk_buff *))
836{
837 struct sk_buff *skb = *pskb;
838
839 if ((out->hard_start_xmit == br_dev_xmit &&
840 okfn != br_nf_forward_finish &&
841 okfn != br_nf_local_out_finish &&
842 okfn != br_dev_queue_push_xmit)
843#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
844 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
845 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
846#endif
847 ) {
848 struct nf_bridge_info *nf_bridge;
849
850 if (!skb->nf_bridge) {
851#ifdef CONFIG_SYSCTL
852 /* This code is executed while in the IP(v6) stack,
853 the version should be 4 or 6. We can't use
854 skb->protocol because that isn't set on
855 PF_INET(6)/LOCAL_OUT. */
856 struct iphdr *ip = skb->nh.iph;
857
858 if (ip->version == 4 && !brnf_call_iptables)
859 return NF_ACCEPT;
860 else if (ip->version == 6 && !brnf_call_ip6tables)
861 return NF_ACCEPT;
862#endif
863 if (hook == NF_IP_POST_ROUTING)
864 return NF_ACCEPT;
865 if (!nf_bridge_alloc(skb))
866 return NF_DROP;
867 }
868
869 nf_bridge = skb->nf_bridge;
870
871 /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
872 * will need the indev then. For a brouter, the real indev
873 * can be a bridge port, so we make sure br_nf_local_out()
874 * doesn't use the bridge parent of the indev by using
875 * the BRNF_DONT_TAKE_PARENT mask. */
876 if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
9666dae5 877 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
1da177e4
LT		 878 nf_bridge->physindev = (struct net_device *)in;
879 }
880#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
881 /* the iptables outdev is br0.x, not br0 */
882 if (out->priv_flags & IFF_802_1Q_VLAN)
883 nf_bridge->netoutdev = (struct net_device *)out;
884#endif
885 return NF_STOP;
886 }
887
888 return NF_ACCEPT;
889}
890
891/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
892 * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
893 * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
894 * ip_refrag() can return NF_STOLEN. */
895static struct nf_hook_ops br_nf_ops[] = {
896 { .hook = br_nf_pre_routing,
897 .owner = THIS_MODULE,
898 .pf = PF_BRIDGE,
899 .hooknum = NF_BR_PRE_ROUTING,
900 .priority = NF_BR_PRI_BRNF, },
901 { .hook = br_nf_local_in,
902 .owner = THIS_MODULE,
903 .pf = PF_BRIDGE,
904 .hooknum = NF_BR_LOCAL_IN,
905 .priority = NF_BR_PRI_BRNF, },
906 { .hook = br_nf_forward_ip,
907 .owner = THIS_MODULE,
908 .pf = PF_BRIDGE,
909 .hooknum = NF_BR_FORWARD,
910 .priority = NF_BR_PRI_BRNF - 1, },
911 { .hook = br_nf_forward_arp,
912 .owner = THIS_MODULE,
913 .pf = PF_BRIDGE,
914 .hooknum = NF_BR_FORWARD,
915 .priority = NF_BR_PRI_BRNF, },
916 { .hook = br_nf_local_out,
917 .owner = THIS_MODULE,
918 .pf = PF_BRIDGE,
919 .hooknum = NF_BR_LOCAL_OUT,
920 .priority = NF_BR_PRI_FIRST, },
921 { .hook = br_nf_post_routing,
922 .owner = THIS_MODULE,
923 .pf = PF_BRIDGE,
924 .hooknum = NF_BR_POST_ROUTING,
925 .priority = NF_BR_PRI_LAST, },
926 { .hook = ip_sabotage_in,
927 .owner = THIS_MODULE,
928 .pf = PF_INET,
929 .hooknum = NF_IP_PRE_ROUTING,
930 .priority = NF_IP_PRI_FIRST, },
931 { .hook = ip_sabotage_in,
932 .owner = THIS_MODULE,
933 .pf = PF_INET6,
934 .hooknum = NF_IP6_PRE_ROUTING,
935 .priority = NF_IP6_PRI_FIRST, },
936 { .hook = ip_sabotage_out,
937 .owner = THIS_MODULE,
938 .pf = PF_INET,
939 .hooknum = NF_IP_FORWARD,
940 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
941 { .hook = ip_sabotage_out,
942 .owner = THIS_MODULE,
943 .pf = PF_INET6,
944 .hooknum = NF_IP6_FORWARD,
945 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
946 { .hook = ip_sabotage_out,
947 .owner = THIS_MODULE,
948 .pf = PF_INET,
949 .hooknum = NF_IP_LOCAL_OUT,
950 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
951 { .hook = ip_sabotage_out,
952 .owner = THIS_MODULE,
953 .pf = PF_INET6,
954 .hooknum = NF_IP6_LOCAL_OUT,
955 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
956 { .hook = ip_sabotage_out,
957 .owner = THIS_MODULE,
958 .pf = PF_INET,
959 .hooknum = NF_IP_POST_ROUTING,
960 .priority = NF_IP_PRI_FIRST, },
961 { .hook = ip_sabotage_out,
962 .owner = THIS_MODULE,
963 .pf = PF_INET6,
964 .hooknum = NF_IP6_POST_ROUTING,
965 .priority = NF_IP6_PRI_FIRST, },
966};
967
968#ifdef CONFIG_SYSCTL
969static
970int brnf_sysctl_call_tables(ctl_table *ctl, int write, struct file * filp,
971 void __user *buffer, size_t *lenp, loff_t *ppos)
972{
973 int ret;
974
975 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
976
977 if (write && *(int *)(ctl->data))
978 *(int *)(ctl->data) = 1;
979 return ret;
980}
981
982static ctl_table brnf_table[] = {
983 {
984 .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
985 .procname = "bridge-nf-call-arptables",
986 .data = &brnf_call_arptables,
987 .maxlen = sizeof(int),
988 .mode = 0644,
989 .proc_handler = &brnf_sysctl_call_tables,
990 },
991 {
992 .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
993 .procname = "bridge-nf-call-iptables",
994 .data = &brnf_call_iptables,
995 .maxlen = sizeof(int),
996 .mode = 0644,
997 .proc_handler = &brnf_sysctl_call_tables,
998 },
999 {
1000 .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
1001 .procname = "bridge-nf-call-ip6tables",
1002 .data = &brnf_call_ip6tables,
1003 .maxlen = sizeof(int),
1004 .mode = 0644,
1005 .proc_handler = &brnf_sysctl_call_tables,
1006 },
1007 {
1008 .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
1009 .procname = "bridge-nf-filter-vlan-tagged",
1010 .data = &brnf_filter_vlan_tagged,
1011 .maxlen = sizeof(int),
1012 .mode = 0644,
1013 .proc_handler = &brnf_sysctl_call_tables,
1014 },
1015 { .ctl_name = 0 }
1016};
1017
1018static ctl_table brnf_bridge_table[] = {
1019 {
1020 .ctl_name = NET_BRIDGE,
1021 .procname = "bridge",
1022 .mode = 0555,
1023 .child = brnf_table,
1024 },
1025 { .ctl_name = 0 }
1026};
1027
1028static ctl_table brnf_net_table[] = {
1029 {
1030 .ctl_name = CTL_NET,
1031 .procname = "net",
1032 .mode = 0555,
1033 .child = brnf_bridge_table,
1034 },
1035 { .ctl_name = 0 }
1036};
1037#endif
1038
1039int br_netfilter_init(void)
1040{
1041 int i;
1042
1043 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1044 int ret;
1045
1046 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1047 continue;
1048
1049 while (i--)
1050 nf_unregister_hook(&br_nf_ops[i]);
1051
1052 return ret;
1053 }
1054
1055#ifdef CONFIG_SYSCTL
1056 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1057 if (brnf_sysctl_header == NULL) {
1058 printk(KERN_WARNING "br_netfilter: can't register to sysctl.\n");
1059 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1060 nf_unregister_hook(&br_nf_ops[i]);
1061 return -EFAULT;
1062 }
1063#endif
1064
1065 printk(KERN_NOTICE "Bridge firewalling registered\n");
1066
1067 return 0;
1068}
1069
1070void br_netfilter_fini(void)
1071{
1072 int i;
1073
1074 for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
1075 nf_unregister_hook(&br_nf_ops[i]);
1076#ifdef CONFIG_SYSCTL
1077 unregister_sysctl_table(brnf_sysctl_header);
1078#endif
1079}
Clone of davem's net-next-2.6 tree