[NET]: fix up misplaced inlines.
[linux-2.6.git] / net / bridge / br_netfilter.c
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/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>
37 #include <linux/inetdevice.h>
38
39 #include <net/ip.h>
40 #include <net/ipv6.h>
41 #include <net/route.h>
42
43 #include <asm/uaccess.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
54 #ifdef CONFIG_SYSCTL
55 static struct ctl_table_header *brnf_sysctl_header;
56 static int brnf_call_iptables __read_mostly = 1;
57 static int brnf_call_ip6tables __read_mostly = 1;
58 static int brnf_call_arptables __read_mostly = 1;
59 static int brnf_filter_vlan_tagged __read_mostly = 1;
60 #else
61 #define brnf_filter_vlan_tagged 1
62 #endif
63
64 static inline __be16 vlan_proto(const struct sk_buff *skb)
65 {
66         return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
67 }
68
69 #define IS_VLAN_IP(skb) \
70         (skb->protocol == htons(ETH_P_8021Q) && \
71          vlan_proto(skb) == htons(ETH_P_IP) &&  \
72          brnf_filter_vlan_tagged)
73
74 #define IS_VLAN_IPV6(skb) \
75         (skb->protocol == htons(ETH_P_8021Q) && \
76          vlan_proto(skb) == htons(ETH_P_IPV6) &&\
77          brnf_filter_vlan_tagged)
78
79 #define IS_VLAN_ARP(skb) \
80         (skb->protocol == htons(ETH_P_8021Q) && \
81          vlan_proto(skb) == htons(ETH_P_ARP) && \
82          brnf_filter_vlan_tagged)
83
84 /* We need these fake structures to make netfilter happy --
85  * lots of places assume that skb->dst != NULL, which isn't
86  * all that unreasonable.
87  *
88  * Currently, we fill in the PMTU entry because netfilter
89  * refragmentation needs it, and the rt_flags entry because
90  * ipt_REJECT needs it.  Future netfilter modules might
91  * require us to fill additional fields. */
92 static struct net_device __fake_net_device = {
93         .hard_header_len        = ETH_HLEN
94 };
95
96 static struct rtable __fake_rtable = {
97         .u = {
98                 .dst = {
99                         .__refcnt               = ATOMIC_INIT(1),
100                         .dev                    = &__fake_net_device,
101                         .path                   = &__fake_rtable.u.dst,
102                         .metrics                = {[RTAX_MTU - 1] = 1500},
103                         .flags                  = DST_NOXFRM,
104                 }
105         },
106         .rt_flags       = 0,
107 };
108
109 static inline struct net_device *bridge_parent(const struct net_device *dev)
110 {
111         struct net_bridge_port *port = rcu_dereference(dev->br_port);
112
113         return port ? port->br->dev : NULL;
114 }
115
116 static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
117 {
118         skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
119         if (likely(skb->nf_bridge))
120                 atomic_set(&(skb->nf_bridge->use), 1);
121
122         return skb->nf_bridge;
123 }
124
125 static inline void nf_bridge_save_header(struct sk_buff *skb)
126 {
127         int header_size = ETH_HLEN;
128
129         if (skb->protocol == htons(ETH_P_8021Q))
130                 header_size += VLAN_HLEN;
131
132         memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
133 }
134
135 /*
136  * When forwarding bridge frames, we save a copy of the original
137  * header before processing.
138  */
139 int nf_bridge_copy_header(struct sk_buff *skb)
140 {
141         int err;
142         int header_size = ETH_HLEN;
143
144         if (skb->protocol == htons(ETH_P_8021Q))
145                 header_size += VLAN_HLEN;
146
147         err = skb_cow(skb, header_size);
148         if (err)
149                 return err;
150
151         memcpy(skb->data - header_size, skb->nf_bridge->data, header_size);
152
153         if (skb->protocol == htons(ETH_P_8021Q))
154                 __skb_push(skb, VLAN_HLEN);
155         return 0;
156 }
157
158 /* PF_BRIDGE/PRE_ROUTING *********************************************/
159 /* Undo the changes made for ip6tables PREROUTING and continue the
160  * bridge PRE_ROUTING hook. */
161 static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
162 {
163         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
164
165         if (nf_bridge->mask & BRNF_PKT_TYPE) {
166                 skb->pkt_type = PACKET_OTHERHOST;
167                 nf_bridge->mask ^= BRNF_PKT_TYPE;
168         }
169         nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
170
171         skb->dst = (struct dst_entry *)&__fake_rtable;
172         dst_hold(skb->dst);
173
174         skb->dev = nf_bridge->physindev;
175         if (skb->protocol == htons(ETH_P_8021Q)) {
176                 skb_push(skb, VLAN_HLEN);
177                 skb->nh.raw -= VLAN_HLEN;
178         }
179         NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
180                        br_handle_frame_finish, 1);
181
182         return 0;
183 }
184
185 static void __br_dnat_complain(void)
186 {
187         static unsigned long last_complaint;
188
189         if (jiffies - last_complaint >= 5 * HZ) {
190                 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
191                        "forwarding to be enabled\n");
192                 last_complaint = jiffies;
193         }
194 }
195
196 /* This requires some explaining. If DNAT has taken place,
197  * we will need to fix up the destination Ethernet address,
198  * and this is a tricky process.
199  *
200  * There are two cases to consider:
201  * 1. The packet was DNAT'ed to a device in the same bridge
202  *    port group as it was received on. We can still bridge
203  *    the packet.
204  * 2. The packet was DNAT'ed to a different device, either
205  *    a non-bridged device or another bridge port group.
206  *    The packet will need to be routed.
207  *
208  * The correct way of distinguishing between these two cases is to
209  * call ip_route_input() and to look at skb->dst->dev, which is
210  * changed to the destination device if ip_route_input() succeeds.
211  *
212  * Let us first consider the case that ip_route_input() succeeds:
213  *
214  * If skb->dst->dev equals the logical bridge device the packet
215  * came in on, we can consider this bridging. We then call
216  * skb->dst->output() which will make the packet enter br_nf_local_out()
217  * not much later. In that function it is assured that the iptables
218  * FORWARD chain is traversed for the packet.
219  *
220  * Otherwise, the packet is considered to be routed and we just
221  * change the destination MAC address so that the packet will
222  * later be passed up to the IP stack to be routed. For a redirected
223  * packet, ip_route_input() will give back the localhost as output device,
224  * which differs from the bridge device.
225  *
226  * Let us now consider the case that ip_route_input() fails:
227  *
228  * This can be because the destination address is martian, in which case
229  * the packet will be dropped.
230  * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
231  * will fail, while __ip_route_output_key() will return success. The source
232  * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
233  * thinks we're handling a locally generated packet and won't care
234  * if IP forwarding is allowed. We send a warning message to the users's
235  * log telling her to put IP forwarding on.
236  *
237  * ip_route_input() will also fail if there is no route available.
238  * In that case we just drop the packet.
239  *
240  * --Lennert, 20020411
241  * --Bart, 20020416 (updated)
242  * --Bart, 20021007 (updated)
243  * --Bart, 20062711 (updated) */
244 static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
245 {
246         if (skb->pkt_type == PACKET_OTHERHOST) {
247                 skb->pkt_type = PACKET_HOST;
248                 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
249         }
250         skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
251
252         skb->dev = bridge_parent(skb->dev);
253         if (!skb->dev)
254                 kfree_skb(skb);
255         else {
256                 if (skb->protocol == htons(ETH_P_8021Q)) {
257                         skb_pull(skb, VLAN_HLEN);
258                         skb->nh.raw += VLAN_HLEN;
259                 }
260                 skb->dst->output(skb);
261         }
262         return 0;
263 }
264
265 static int br_nf_pre_routing_finish(struct sk_buff *skb)
266 {
267         struct net_device *dev = skb->dev;
268         struct iphdr *iph = skb->nh.iph;
269         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
270         int err;
271
272         if (nf_bridge->mask & BRNF_PKT_TYPE) {
273                 skb->pkt_type = PACKET_OTHERHOST;
274                 nf_bridge->mask ^= BRNF_PKT_TYPE;
275         }
276         nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
277         if (dnat_took_place(skb)) {
278                 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
279                         struct rtable *rt;
280                         struct flowi fl = {
281                                 .nl_u = {
282                                         .ip4_u = {
283                                                  .daddr = iph->daddr,
284                                                  .saddr = 0,
285                                                  .tos = RT_TOS(iph->tos) },
286                                 },
287                                 .proto = 0,
288                         };
289                         struct in_device *in_dev = in_dev_get(dev);
290
291                         /* If err equals -EHOSTUNREACH the error is due to a
292                          * martian destination or due to the fact that
293                          * forwarding is disabled. For most martian packets,
294                          * ip_route_output_key() will fail. It won't fail for 2 types of
295                          * martian destinations: loopback destinations and destination
296                          * 0.0.0.0. In both cases the packet will be dropped because the
297                          * destination is the loopback device and not the bridge. */
298                         if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
299                                 goto free_skb;
300
301                         if (!ip_route_output_key(&rt, &fl)) {
302                                 /* - Bridged-and-DNAT'ed traffic doesn't
303                                  *   require ip_forwarding. */
304                                 if (((struct dst_entry *)rt)->dev == dev) {
305                                         skb->dst = (struct dst_entry *)rt;
306                                         goto bridged_dnat;
307                                 }
308                                 /* we are sure that forwarding is disabled, so printing
309                                  * this message is no problem. Note that the packet could
310                                  * still have a martian destination address, in which case
311                                  * the packet could be dropped even if forwarding were enabled */
312                                 __br_dnat_complain();
313                                 dst_release((struct dst_entry *)rt);
314                         }
315 free_skb:
316                         kfree_skb(skb);
317                         return 0;
318                 } else {
319                         if (skb->dst->dev == dev) {
320 bridged_dnat:
321                                 /* Tell br_nf_local_out this is a
322                                  * bridged frame */
323                                 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
324                                 skb->dev = nf_bridge->physindev;
325                                 if (skb->protocol ==
326                                     htons(ETH_P_8021Q)) {
327                                         skb_push(skb, VLAN_HLEN);
328                                         skb->nh.raw -= VLAN_HLEN;
329                                 }
330                                 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
331                                                skb, skb->dev, NULL,
332                                                br_nf_pre_routing_finish_bridge,
333                                                1);
334                                 return 0;
335                         }
336                         memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
337                         skb->pkt_type = PACKET_HOST;
338                 }
339         } else {
340                 skb->dst = (struct dst_entry *)&__fake_rtable;
341                 dst_hold(skb->dst);
342         }
343
344         skb->dev = nf_bridge->physindev;
345         if (skb->protocol == htons(ETH_P_8021Q)) {
346                 skb_push(skb, VLAN_HLEN);
347                 skb->nh.raw -= VLAN_HLEN;
348         }
349         NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
350                        br_handle_frame_finish, 1);
351
352         return 0;
353 }
354
355 /* Some common code for IPv4/IPv6 */
356 static struct net_device *setup_pre_routing(struct sk_buff *skb)
357 {
358         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
359
360         if (skb->pkt_type == PACKET_OTHERHOST) {
361                 skb->pkt_type = PACKET_HOST;
362                 nf_bridge->mask |= BRNF_PKT_TYPE;
363         }
364
365         nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
366         nf_bridge->physindev = skb->dev;
367         skb->dev = bridge_parent(skb->dev);
368
369         return skb->dev;
370 }
371
372 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
373 static int check_hbh_len(struct sk_buff *skb)
374 {
375         unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
376         u32 pkt_len;
377         int off = raw - skb->nh.raw;
378         int len = (raw[1] + 1) << 3;
379
380         if ((raw + len) - skb->data > skb_headlen(skb))
381                 goto bad;
382
383         off += 2;
384         len -= 2;
385
386         while (len > 0) {
387                 int optlen = skb->nh.raw[off + 1] + 2;
388
389                 switch (skb->nh.raw[off]) {
390                 case IPV6_TLV_PAD0:
391                         optlen = 1;
392                         break;
393
394                 case IPV6_TLV_PADN:
395                         break;
396
397                 case IPV6_TLV_JUMBO:
398                         if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
399                                 goto bad;
400                         pkt_len = ntohl(*(__be32 *) (skb->nh.raw + off + 2));
401                         if (pkt_len <= IPV6_MAXPLEN ||
402                             skb->nh.ipv6h->payload_len)
403                                 goto bad;
404                         if (pkt_len > skb->len - sizeof(struct ipv6hdr))
405                                 goto bad;
406                         if (pskb_trim_rcsum(skb,
407                                             pkt_len + sizeof(struct ipv6hdr)))
408                                 goto bad;
409                         break;
410                 default:
411                         if (optlen > len)
412                                 goto bad;
413                         break;
414                 }
415                 off += optlen;
416                 len -= optlen;
417         }
418         if (len == 0)
419                 return 0;
420 bad:
421         return -1;
422
423 }
424
425 /* Replicate the checks that IPv6 does on packet reception and pass the packet
426  * to ip6tables, which doesn't support NAT, so things are fairly simple. */
427 static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
428                                            struct sk_buff *skb,
429                                            const struct net_device *in,
430                                            const struct net_device *out,
431                                            int (*okfn)(struct sk_buff *))
432 {
433         struct ipv6hdr *hdr;
434         u32 pkt_len;
435
436         if (skb->len < sizeof(struct ipv6hdr))
437                 goto inhdr_error;
438
439         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
440                 goto inhdr_error;
441
442         hdr = skb->nh.ipv6h;
443
444         if (hdr->version != 6)
445                 goto inhdr_error;
446
447         pkt_len = ntohs(hdr->payload_len);
448
449         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
450                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
451                         goto inhdr_error;
452                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
453                         goto inhdr_error;
454         }
455         if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
456                 goto inhdr_error;
457
458         nf_bridge_put(skb->nf_bridge);
459         if (!nf_bridge_alloc(skb))
460                 return NF_DROP;
461         if (!setup_pre_routing(skb))
462                 return NF_DROP;
463
464         NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
465                 br_nf_pre_routing_finish_ipv6);
466
467         return NF_STOLEN;
468
469 inhdr_error:
470         return NF_DROP;
471 }
472
473 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
474  * Replicate the checks that IPv4 does on packet reception.
475  * Set skb->dev to the bridge device (i.e. parent of the
476  * receiving device) to make netfilter happy, the REDIRECT
477  * target in particular.  Save the original destination IP
478  * address to be able to detect DNAT afterwards. */
479 static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
480                                       const struct net_device *in,
481                                       const struct net_device *out,
482                                       int (*okfn)(struct sk_buff *))
483 {
484         struct iphdr *iph;
485         __u32 len;
486         struct sk_buff *skb = *pskb;
487
488         if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
489 #ifdef CONFIG_SYSCTL
490                 if (!brnf_call_ip6tables)
491                         return NF_ACCEPT;
492 #endif
493                 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
494                         goto out;
495
496                 if (skb->protocol == htons(ETH_P_8021Q)) {
497                         skb_pull_rcsum(skb, VLAN_HLEN);
498                         skb->nh.raw += VLAN_HLEN;
499                 }
500                 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
501         }
502 #ifdef CONFIG_SYSCTL
503         if (!brnf_call_iptables)
504                 return NF_ACCEPT;
505 #endif
506
507         if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
508                 return NF_ACCEPT;
509
510         if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
511                 goto out;
512
513         if (skb->protocol == htons(ETH_P_8021Q)) {
514                 skb_pull_rcsum(skb, VLAN_HLEN);
515                 skb->nh.raw += VLAN_HLEN;
516         }
517
518         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
519                 goto inhdr_error;
520
521         iph = skb->nh.iph;
522         if (iph->ihl < 5 || iph->version != 4)
523                 goto inhdr_error;
524
525         if (!pskb_may_pull(skb, 4 * iph->ihl))
526                 goto inhdr_error;
527
528         iph = skb->nh.iph;
529         if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
530                 goto inhdr_error;
531
532         len = ntohs(iph->tot_len);
533         if (skb->len < len || len < 4 * iph->ihl)
534                 goto inhdr_error;
535
536         pskb_trim_rcsum(skb, len);
537
538         nf_bridge_put(skb->nf_bridge);
539         if (!nf_bridge_alloc(skb))
540                 return NF_DROP;
541         if (!setup_pre_routing(skb))
542                 return NF_DROP;
543         store_orig_dstaddr(skb);
544
545         NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
546                 br_nf_pre_routing_finish);
547
548         return NF_STOLEN;
549
550 inhdr_error:
551 //      IP_INC_STATS_BH(IpInHdrErrors);
552 out:
553         return NF_DROP;
554 }
555
556
557 /* PF_BRIDGE/LOCAL_IN ************************************************/
558 /* The packet is locally destined, which requires a real
559  * dst_entry, so detach the fake one.  On the way up, the
560  * packet would pass through PRE_ROUTING again (which already
561  * took place when the packet entered the bridge), but we
562  * register an IPv4 PRE_ROUTING 'sabotage' hook that will
563  * prevent this from happening. */
564 static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
565                                    const struct net_device *in,
566                                    const struct net_device *out,
567                                    int (*okfn)(struct sk_buff *))
568 {
569         struct sk_buff *skb = *pskb;
570
571         if (skb->dst == (struct dst_entry *)&__fake_rtable) {
572                 dst_release(skb->dst);
573                 skb->dst = NULL;
574         }
575
576         return NF_ACCEPT;
577 }
578
579 /* PF_BRIDGE/FORWARD *************************************************/
580 static int br_nf_forward_finish(struct sk_buff *skb)
581 {
582         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
583         struct net_device *in;
584
585         if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
586                 in = nf_bridge->physindev;
587                 if (nf_bridge->mask & BRNF_PKT_TYPE) {
588                         skb->pkt_type = PACKET_OTHERHOST;
589                         nf_bridge->mask ^= BRNF_PKT_TYPE;
590                 }
591         } else {
592                 in = *((struct net_device **)(skb->cb));
593         }
594         if (skb->protocol == htons(ETH_P_8021Q)) {
595                 skb_push(skb, VLAN_HLEN);
596                 skb->nh.raw -= VLAN_HLEN;
597         }
598         NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
599                        skb->dev, br_forward_finish, 1);
600         return 0;
601 }
602
603 /* This is the 'purely bridged' case.  For IP, we pass the packet to
604  * netfilter with indev and outdev set to the bridge device,
605  * but we are still able to filter on the 'real' indev/outdev
606  * because of the physdev module. For ARP, indev and outdev are the
607  * bridge ports. */
608 static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
609                                      const struct net_device *in,
610                                      const struct net_device *out,
611                                      int (*okfn)(struct sk_buff *))
612 {
613         struct sk_buff *skb = *pskb;
614         struct nf_bridge_info *nf_bridge;
615         struct net_device *parent;
616         int pf;
617
618         if (!skb->nf_bridge)
619                 return NF_ACCEPT;
620
621         parent = bridge_parent(out);
622         if (!parent)
623                 return NF_DROP;
624
625         if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
626                 pf = PF_INET;
627         else
628                 pf = PF_INET6;
629
630         if (skb->protocol == htons(ETH_P_8021Q)) {
631                 skb_pull(*pskb, VLAN_HLEN);
632                 (*pskb)->nh.raw += VLAN_HLEN;
633         }
634
635         nf_bridge = skb->nf_bridge;
636         if (skb->pkt_type == PACKET_OTHERHOST) {
637                 skb->pkt_type = PACKET_HOST;
638                 nf_bridge->mask |= BRNF_PKT_TYPE;
639         }
640
641         /* The physdev module checks on this */
642         nf_bridge->mask |= BRNF_BRIDGED;
643         nf_bridge->physoutdev = skb->dev;
644
645         NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
646                 br_nf_forward_finish);
647
648         return NF_STOLEN;
649 }
650
651 static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
652                                       const struct net_device *in,
653                                       const struct net_device *out,
654                                       int (*okfn)(struct sk_buff *))
655 {
656         struct sk_buff *skb = *pskb;
657         struct net_device **d = (struct net_device **)(skb->cb);
658
659 #ifdef CONFIG_SYSCTL
660         if (!brnf_call_arptables)
661                 return NF_ACCEPT;
662 #endif
663
664         if (skb->protocol != htons(ETH_P_ARP)) {
665                 if (!IS_VLAN_ARP(skb))
666                         return NF_ACCEPT;
667                 skb_pull(*pskb, VLAN_HLEN);
668                 (*pskb)->nh.raw += VLAN_HLEN;
669         }
670
671         if (skb->nh.arph->ar_pln != 4) {
672                 if (IS_VLAN_ARP(skb)) {
673                         skb_push(*pskb, VLAN_HLEN);
674                         (*pskb)->nh.raw -= VLAN_HLEN;
675                 }
676                 return NF_ACCEPT;
677         }
678         *d = (struct net_device *)in;
679         NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
680                 (struct net_device *)out, br_nf_forward_finish);
681
682         return NF_STOLEN;
683 }
684
685 /* PF_BRIDGE/LOCAL_OUT ***********************************************
686  *
687  * This function sees both locally originated IP packets and forwarded
688  * IP packets (in both cases the destination device is a bridge
689  * device). It also sees bridged-and-DNAT'ed packets.
690  *
691  * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
692  * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
693  * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
694  * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
695  * will be executed.
696  */
697 static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
698                                     const struct net_device *in,
699                                     const struct net_device *out,
700                                     int (*okfn)(struct sk_buff *))
701 {
702         struct net_device *realindev;
703         struct sk_buff *skb = *pskb;
704         struct nf_bridge_info *nf_bridge;
705
706         if (!skb->nf_bridge)
707                 return NF_ACCEPT;
708
709         nf_bridge = skb->nf_bridge;
710         if (!(nf_bridge->mask & BRNF_BRIDGED_DNAT))
711                 return NF_ACCEPT;
712
713         /* Bridged, take PF_BRIDGE/FORWARD.
714          * (see big note in front of br_nf_pre_routing_finish) */
715         nf_bridge->physoutdev = skb->dev;
716         realindev = nf_bridge->physindev;
717
718         if (nf_bridge->mask & BRNF_PKT_TYPE) {
719                 skb->pkt_type = PACKET_OTHERHOST;
720                 nf_bridge->mask ^= BRNF_PKT_TYPE;
721         }
722         if (skb->protocol == htons(ETH_P_8021Q)) {
723                 skb_push(skb, VLAN_HLEN);
724                 skb->nh.raw -= VLAN_HLEN;
725         }
726
727         NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev, skb->dev,
728                 br_forward_finish);
729         return NF_STOLEN;
730 }
731
732 static int br_nf_dev_queue_xmit(struct sk_buff *skb)
733 {
734         if (skb->protocol == htons(ETH_P_IP) &&
735             skb->len > skb->dev->mtu &&
736             !skb_is_gso(skb))
737                 return ip_fragment(skb, br_dev_queue_push_xmit);
738         else
739                 return br_dev_queue_push_xmit(skb);
740 }
741
742 /* PF_BRIDGE/POST_ROUTING ********************************************/
743 static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
744                                        const struct net_device *in,
745                                        const struct net_device *out,
746                                        int (*okfn)(struct sk_buff *))
747 {
748         struct sk_buff *skb = *pskb;
749         struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
750         struct net_device *realoutdev = bridge_parent(skb->dev);
751         int pf;
752
753 #ifdef CONFIG_NETFILTER_DEBUG
754         /* Be very paranoid. This probably won't happen anymore, but let's
755          * keep the check just to be sure... */
756         if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
757                 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
758                        "bad mac.raw pointer.\n");
759                 goto print_error;
760         }
761 #endif
762
763         if (!nf_bridge)
764                 return NF_ACCEPT;
765
766         if (!realoutdev)
767                 return NF_DROP;
768
769         if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
770                 pf = PF_INET;
771         else
772                 pf = PF_INET6;
773
774 #ifdef CONFIG_NETFILTER_DEBUG
775         if (skb->dst == NULL) {
776                 printk(KERN_INFO "br_netfilter post_routing: skb->dst == NULL\n");
777                 goto print_error;
778         }
779 #endif
780
781         /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
782          * about the value of skb->pkt_type. */
783         if (skb->pkt_type == PACKET_OTHERHOST) {
784                 skb->pkt_type = PACKET_HOST;
785                 nf_bridge->mask |= BRNF_PKT_TYPE;
786         }
787
788         if (skb->protocol == htons(ETH_P_8021Q)) {
789                 skb_pull(skb, VLAN_HLEN);
790                 skb->nh.raw += VLAN_HLEN;
791         }
792
793         nf_bridge_save_header(skb);
794
795 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
796         if (nf_bridge->netoutdev)
797                 realoutdev = nf_bridge->netoutdev;
798 #endif
799         NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
800                 br_nf_dev_queue_xmit);
801
802         return NF_STOLEN;
803
804 #ifdef CONFIG_NETFILTER_DEBUG
805 print_error:
806         if (skb->dev != NULL) {
807                 printk("[%s]", skb->dev->name);
808                 if (realoutdev)
809                         printk("[%s]", realoutdev->name);
810         }
811         printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
812                skb->data);
813         dump_stack();
814         return NF_ACCEPT;
815 #endif
816 }
817
818 /* IP/SABOTAGE *****************************************************/
819 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
820  * for the second time. */
821 static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
822                                    const struct net_device *in,
823                                    const struct net_device *out,
824                                    int (*okfn)(struct sk_buff *))
825 {
826         if ((*pskb)->nf_bridge &&
827             !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
828                 return NF_STOP;
829         }
830
831         return NF_ACCEPT;
832 }
833
834 /* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
835  * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
836  * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
837  * ip_refrag() can return NF_STOLEN. */
838 static struct nf_hook_ops br_nf_ops[] = {
839         { .hook = br_nf_pre_routing,
840           .owner = THIS_MODULE,
841           .pf = PF_BRIDGE,
842           .hooknum = NF_BR_PRE_ROUTING,
843           .priority = NF_BR_PRI_BRNF, },
844         { .hook = br_nf_local_in,
845           .owner = THIS_MODULE,
846           .pf = PF_BRIDGE,
847           .hooknum = NF_BR_LOCAL_IN,
848           .priority = NF_BR_PRI_BRNF, },
849         { .hook = br_nf_forward_ip,
850           .owner = THIS_MODULE,
851           .pf = PF_BRIDGE,
852           .hooknum = NF_BR_FORWARD,
853           .priority = NF_BR_PRI_BRNF - 1, },
854         { .hook = br_nf_forward_arp,
855           .owner = THIS_MODULE,
856           .pf = PF_BRIDGE,
857           .hooknum = NF_BR_FORWARD,
858           .priority = NF_BR_PRI_BRNF, },
859         { .hook = br_nf_local_out,
860           .owner = THIS_MODULE,
861           .pf = PF_BRIDGE,
862           .hooknum = NF_BR_LOCAL_OUT,
863           .priority = NF_BR_PRI_FIRST, },
864         { .hook = br_nf_post_routing,
865           .owner = THIS_MODULE,
866           .pf = PF_BRIDGE,
867           .hooknum = NF_BR_POST_ROUTING,
868           .priority = NF_BR_PRI_LAST, },
869         { .hook = ip_sabotage_in,
870           .owner = THIS_MODULE,
871           .pf = PF_INET,
872           .hooknum = NF_IP_PRE_ROUTING,
873           .priority = NF_IP_PRI_FIRST, },
874         { .hook = ip_sabotage_in,
875           .owner = THIS_MODULE,
876           .pf = PF_INET6,
877           .hooknum = NF_IP6_PRE_ROUTING,
878           .priority = NF_IP6_PRI_FIRST, },
879 };
880
881 #ifdef CONFIG_SYSCTL
882 static
883 int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
884                             void __user * buffer, size_t * lenp, loff_t * ppos)
885 {
886         int ret;
887
888         ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
889
890         if (write && *(int *)(ctl->data))
891                 *(int *)(ctl->data) = 1;
892         return ret;
893 }
894
895 static ctl_table brnf_table[] = {
896         {
897                 .ctl_name       = NET_BRIDGE_NF_CALL_ARPTABLES,
898                 .procname       = "bridge-nf-call-arptables",
899                 .data           = &brnf_call_arptables,
900                 .maxlen         = sizeof(int),
901                 .mode           = 0644,
902                 .proc_handler   = &brnf_sysctl_call_tables,
903         },
904         {
905                 .ctl_name       = NET_BRIDGE_NF_CALL_IPTABLES,
906                 .procname       = "bridge-nf-call-iptables",
907                 .data           = &brnf_call_iptables,
908                 .maxlen         = sizeof(int),
909                 .mode           = 0644,
910                 .proc_handler   = &brnf_sysctl_call_tables,
911         },
912         {
913                 .ctl_name       = NET_BRIDGE_NF_CALL_IP6TABLES,
914                 .procname       = "bridge-nf-call-ip6tables",
915                 .data           = &brnf_call_ip6tables,
916                 .maxlen         = sizeof(int),
917                 .mode           = 0644,
918                 .proc_handler   = &brnf_sysctl_call_tables,
919         },
920         {
921                 .ctl_name       = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
922                 .procname       = "bridge-nf-filter-vlan-tagged",
923                 .data           = &brnf_filter_vlan_tagged,
924                 .maxlen         = sizeof(int),
925                 .mode           = 0644,
926                 .proc_handler   = &brnf_sysctl_call_tables,
927         },
928         { .ctl_name = 0 }
929 };
930
931 static ctl_table brnf_bridge_table[] = {
932         {
933                 .ctl_name       = NET_BRIDGE,
934                 .procname       = "bridge",
935                 .mode           = 0555,
936                 .child          = brnf_table,
937         },
938         { .ctl_name = 0 }
939 };
940
941 static ctl_table brnf_net_table[] = {
942         {
943                 .ctl_name       = CTL_NET,
944                 .procname       = "net",
945                 .mode           = 0555,
946                 .child          = brnf_bridge_table,
947         },
948         { .ctl_name = 0 }
949 };
950 #endif
951
952 int __init br_netfilter_init(void)
953 {
954         int ret;
955
956         ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
957         if (ret < 0)
958                 return ret;
959 #ifdef CONFIG_SYSCTL
960         brnf_sysctl_header = register_sysctl_table(brnf_net_table);
961         if (brnf_sysctl_header == NULL) {
962                 printk(KERN_WARNING
963                        "br_netfilter: can't register to sysctl.\n");
964                 nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
965                 return -ENOMEM;
966         }
967 #endif
968         printk(KERN_NOTICE "Bridge firewalling registered\n");
969         return 0;
970 }
971
972 void br_netfilter_fini(void)
973 {
974         nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
975 #ifdef CONFIG_SYSCTL
976         unregister_sysctl_table(brnf_sysctl_header);
977 #endif
978 }