[PATCH] w1: Userspace communication protocol over connector.
[linux-2.6/verdex.git] / net / bridge / br_netfilter.c
blob3e41f9d6d51c7f27d167cee06ddff99556c8dca8
1 /*
2 * Handle firewalling
3 * Linux ethernet bridge
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 * Bart De Schuymer (maintainer) <bdschuym@pandora.be>
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)
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.
21 * Lennert dedicates this file to Kerstin Wurdinger.
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>
38 #include <net/ip.h>
39 #include <net/ipv6.h>
40 #include <net/route.h>
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
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)
54 #ifdef CONFIG_SYSCTL
55 static struct ctl_table_header *brnf_sysctl_header;
56 static int brnf_call_iptables = 1;
57 static int brnf_call_ip6tables = 1;
58 static int brnf_call_arptables = 1;
59 static int brnf_filter_vlan_tagged = 1;
60 #else
61 #define brnf_filter_vlan_tagged 1
62 #endif
64 static __be16 inline vlan_proto(const struct sk_buff *skb)
66 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
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)
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)
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)
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.
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
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,
106 .rt_flags = 0,
109 static inline struct net_device *bridge_parent(const struct net_device *dev)
111 struct net_bridge_port *port = rcu_dereference(dev->br_port);
113 return port ? port->br->dev : NULL;
116 static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
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);
122 return skb->nf_bridge;
125 static inline void nf_bridge_save_header(struct sk_buff *skb)
127 int header_size = 16;
129 if (skb->protocol == htons(ETH_P_8021Q))
130 header_size = 18;
132 memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
135 /* PF_BRIDGE/PRE_ROUTING *********************************************/
136 /* Undo the changes made for ip6tables PREROUTING and continue the
137 * bridge PRE_ROUTING hook. */
138 static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
140 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
142 if (nf_bridge->mask & BRNF_PKT_TYPE) {
143 skb->pkt_type = PACKET_OTHERHOST;
144 nf_bridge->mask ^= BRNF_PKT_TYPE;
146 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
148 skb->dst = (struct dst_entry *)&__fake_rtable;
149 dst_hold(skb->dst);
151 skb->dev = nf_bridge->physindev;
152 if (skb->protocol == htons(ETH_P_8021Q)) {
153 skb_push(skb, VLAN_HLEN);
154 skb->nh.raw -= VLAN_HLEN;
156 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
157 br_handle_frame_finish, 1);
159 return 0;
162 static void __br_dnat_complain(void)
164 static unsigned long last_complaint;
166 if (jiffies - last_complaint >= 5 * HZ) {
167 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
168 "forwarding to be enabled\n");
169 last_complaint = jiffies;
173 /* This requires some explaining. If DNAT has taken place,
174 * we will need to fix up the destination Ethernet address,
175 * and this is a tricky process.
177 * There are two cases to consider:
178 * 1. The packet was DNAT'ed to a device in the same bridge
179 * port group as it was received on. We can still bridge
180 * the packet.
181 * 2. The packet was DNAT'ed to a different device, either
182 * a non-bridged device or another bridge port group.
183 * The packet will need to be routed.
185 * The correct way of distinguishing between these two cases is to
186 * call ip_route_input() and to look at skb->dst->dev, which is
187 * changed to the destination device if ip_route_input() succeeds.
189 * Let us first consider the case that ip_route_input() succeeds:
191 * If skb->dst->dev equals the logical bridge device the packet
192 * came in on, we can consider this bridging. We then call
193 * skb->dst->output() which will make the packet enter br_nf_local_out()
194 * not much later. In that function it is assured that the iptables
195 * FORWARD chain is traversed for the packet.
197 * Otherwise, the packet is considered to be routed and we just
198 * change the destination MAC address so that the packet will
199 * later be passed up to the IP stack to be routed.
201 * Let us now consider the case that ip_route_input() fails:
203 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
204 * will fail, while __ip_route_output_key() will return success. The source
205 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
206 * thinks we're handling a locally generated packet and won't care
207 * if IP forwarding is allowed. We send a warning message to the users's
208 * log telling her to put IP forwarding on.
210 * ip_route_input() will also fail if there is no route available.
211 * In that case we just drop the packet.
213 * --Lennert, 20020411
214 * --Bart, 20020416 (updated)
215 * --Bart, 20021007 (updated) */
216 static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
218 if (skb->pkt_type == PACKET_OTHERHOST) {
219 skb->pkt_type = PACKET_HOST;
220 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
222 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
224 skb->dev = bridge_parent(skb->dev);
225 if (!skb->dev)
226 kfree_skb(skb);
227 else {
228 if (skb->protocol == htons(ETH_P_8021Q)) {
229 skb_pull(skb, VLAN_HLEN);
230 skb->nh.raw += VLAN_HLEN;
232 skb->dst->output(skb);
234 return 0;
237 static int br_nf_pre_routing_finish(struct sk_buff *skb)
239 struct net_device *dev = skb->dev;
240 struct iphdr *iph = skb->nh.iph;
241 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
243 if (nf_bridge->mask & BRNF_PKT_TYPE) {
244 skb->pkt_type = PACKET_OTHERHOST;
245 nf_bridge->mask ^= BRNF_PKT_TYPE;
247 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
249 if (dnat_took_place(skb)) {
250 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev)) {
251 struct rtable *rt;
252 struct flowi fl = {
253 .nl_u = {
254 .ip4_u = {
255 .daddr = iph->daddr,
256 .saddr = 0,
257 .tos = RT_TOS(iph->tos) },
259 .proto = 0,
262 if (!ip_route_output_key(&rt, &fl)) {
263 /* - Bridged-and-DNAT'ed traffic doesn't
264 * require ip_forwarding.
265 * - Deal with redirected traffic. */
266 if (((struct dst_entry *)rt)->dev == dev ||
267 rt->rt_type == RTN_LOCAL) {
268 skb->dst = (struct dst_entry *)rt;
269 goto bridged_dnat;
271 __br_dnat_complain();
272 dst_release((struct dst_entry *)rt);
274 kfree_skb(skb);
275 return 0;
276 } else {
277 if (skb->dst->dev == dev) {
278 bridged_dnat:
279 /* Tell br_nf_local_out this is a
280 * bridged frame */
281 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
282 skb->dev = nf_bridge->physindev;
283 if (skb->protocol ==
284 htons(ETH_P_8021Q)) {
285 skb_push(skb, VLAN_HLEN);
286 skb->nh.raw -= VLAN_HLEN;
288 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
289 skb, skb->dev, NULL,
290 br_nf_pre_routing_finish_bridge,
292 return 0;
294 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
295 skb->pkt_type = PACKET_HOST;
297 } else {
298 skb->dst = (struct dst_entry *)&__fake_rtable;
299 dst_hold(skb->dst);
302 skb->dev = nf_bridge->physindev;
303 if (skb->protocol == htons(ETH_P_8021Q)) {
304 skb_push(skb, VLAN_HLEN);
305 skb->nh.raw -= VLAN_HLEN;
307 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
308 br_handle_frame_finish, 1);
310 return 0;
313 /* Some common code for IPv4/IPv6 */
314 static struct net_device *setup_pre_routing(struct sk_buff *skb)
316 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
318 if (skb->pkt_type == PACKET_OTHERHOST) {
319 skb->pkt_type = PACKET_HOST;
320 nf_bridge->mask |= BRNF_PKT_TYPE;
323 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
324 nf_bridge->physindev = skb->dev;
325 skb->dev = bridge_parent(skb->dev);
327 return skb->dev;
330 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
331 static int check_hbh_len(struct sk_buff *skb)
333 unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
334 u32 pkt_len;
335 int off = raw - skb->nh.raw;
336 int len = (raw[1] + 1) << 3;
338 if ((raw + len) - skb->data > skb_headlen(skb))
339 goto bad;
341 off += 2;
342 len -= 2;
344 while (len > 0) {
345 int optlen = skb->nh.raw[off + 1] + 2;
347 switch (skb->nh.raw[off]) {
348 case IPV6_TLV_PAD0:
349 optlen = 1;
350 break;
352 case IPV6_TLV_PADN:
353 break;
355 case IPV6_TLV_JUMBO:
356 if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
357 goto bad;
358 pkt_len = ntohl(*(u32 *) (skb->nh.raw + off + 2));
359 if (pkt_len <= IPV6_MAXPLEN ||
360 skb->nh.ipv6h->payload_len)
361 goto bad;
362 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
363 goto bad;
364 if (pskb_trim_rcsum(skb,
365 pkt_len + sizeof(struct ipv6hdr)))
366 goto bad;
367 break;
368 default:
369 if (optlen > len)
370 goto bad;
371 break;
373 off += optlen;
374 len -= optlen;
376 if (len == 0)
377 return 0;
378 bad:
379 return -1;
383 /* Replicate the checks that IPv6 does on packet reception and pass the packet
384 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
385 static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
386 struct sk_buff *skb,
387 const struct net_device *in,
388 const struct net_device *out,
389 int (*okfn)(struct sk_buff *))
391 struct ipv6hdr *hdr;
392 u32 pkt_len;
394 if (skb->len < sizeof(struct ipv6hdr))
395 goto inhdr_error;
397 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
398 goto inhdr_error;
400 hdr = skb->nh.ipv6h;
402 if (hdr->version != 6)
403 goto inhdr_error;
405 pkt_len = ntohs(hdr->payload_len);
407 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
408 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
409 goto inhdr_error;
410 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
411 goto inhdr_error;
413 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
414 goto inhdr_error;
416 nf_bridge_put(skb->nf_bridge);
417 if (!nf_bridge_alloc(skb))
418 return NF_DROP;
419 if (!setup_pre_routing(skb))
420 return NF_DROP;
422 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
423 br_nf_pre_routing_finish_ipv6);
425 return NF_STOLEN;
427 inhdr_error:
428 return NF_DROP;
431 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
432 * Replicate the checks that IPv4 does on packet reception.
433 * Set skb->dev to the bridge device (i.e. parent of the
434 * receiving device) to make netfilter happy, the REDIRECT
435 * target in particular. Save the original destination IP
436 * address to be able to detect DNAT afterwards. */
437 static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
438 const struct net_device *in,
439 const struct net_device *out,
440 int (*okfn)(struct sk_buff *))
442 struct iphdr *iph;
443 __u32 len;
444 struct sk_buff *skb = *pskb;
446 if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
447 #ifdef CONFIG_SYSCTL
448 if (!brnf_call_ip6tables)
449 return NF_ACCEPT;
450 #endif
451 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
452 goto out;
454 if (skb->protocol == htons(ETH_P_8021Q)) {
455 skb_pull_rcsum(skb, VLAN_HLEN);
456 skb->nh.raw += VLAN_HLEN;
458 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
460 #ifdef CONFIG_SYSCTL
461 if (!brnf_call_iptables)
462 return NF_ACCEPT;
463 #endif
465 if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
466 return NF_ACCEPT;
468 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
469 goto out;
471 if (skb->protocol == htons(ETH_P_8021Q)) {
472 skb_pull_rcsum(skb, VLAN_HLEN);
473 skb->nh.raw += VLAN_HLEN;
476 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
477 goto inhdr_error;
479 iph = skb->nh.iph;
480 if (iph->ihl < 5 || iph->version != 4)
481 goto inhdr_error;
483 if (!pskb_may_pull(skb, 4 * iph->ihl))
484 goto inhdr_error;
486 iph = skb->nh.iph;
487 if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
488 goto inhdr_error;
490 len = ntohs(iph->tot_len);
491 if (skb->len < len || len < 4 * iph->ihl)
492 goto inhdr_error;
494 pskb_trim_rcsum(skb, len);
496 nf_bridge_put(skb->nf_bridge);
497 if (!nf_bridge_alloc(skb))
498 return NF_DROP;
499 if (!setup_pre_routing(skb))
500 return NF_DROP;
501 store_orig_dstaddr(skb);
503 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
504 br_nf_pre_routing_finish);
506 return NF_STOLEN;
508 inhdr_error:
509 // IP_INC_STATS_BH(IpInHdrErrors);
510 out:
511 return NF_DROP;
515 /* PF_BRIDGE/LOCAL_IN ************************************************/
516 /* The packet is locally destined, which requires a real
517 * dst_entry, so detach the fake one. On the way up, the
518 * packet would pass through PRE_ROUTING again (which already
519 * took place when the packet entered the bridge), but we
520 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
521 * prevent this from happening. */
522 static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
523 const struct net_device *in,
524 const struct net_device *out,
525 int (*okfn)(struct sk_buff *))
527 struct sk_buff *skb = *pskb;
529 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
530 dst_release(skb->dst);
531 skb->dst = NULL;
534 return NF_ACCEPT;
537 /* PF_BRIDGE/FORWARD *************************************************/
538 static int br_nf_forward_finish(struct sk_buff *skb)
540 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
541 struct net_device *in;
543 if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
544 in = nf_bridge->physindev;
545 if (nf_bridge->mask & BRNF_PKT_TYPE) {
546 skb->pkt_type = PACKET_OTHERHOST;
547 nf_bridge->mask ^= BRNF_PKT_TYPE;
549 } else {
550 in = *((struct net_device **)(skb->cb));
552 if (skb->protocol == htons(ETH_P_8021Q)) {
553 skb_push(skb, VLAN_HLEN);
554 skb->nh.raw -= VLAN_HLEN;
556 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
557 skb->dev, br_forward_finish, 1);
558 return 0;
561 /* This is the 'purely bridged' case. For IP, we pass the packet to
562 * netfilter with indev and outdev set to the bridge device,
563 * but we are still able to filter on the 'real' indev/outdev
564 * because of the physdev module. For ARP, indev and outdev are the
565 * bridge ports. */
566 static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
567 const struct net_device *in,
568 const struct net_device *out,
569 int (*okfn)(struct sk_buff *))
571 struct sk_buff *skb = *pskb;
572 struct nf_bridge_info *nf_bridge;
573 struct net_device *parent;
574 int pf;
576 if (!skb->nf_bridge)
577 return NF_ACCEPT;
579 parent = bridge_parent(out);
580 if (!parent)
581 return NF_DROP;
583 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
584 pf = PF_INET;
585 else
586 pf = PF_INET6;
588 if (skb->protocol == htons(ETH_P_8021Q)) {
589 skb_pull(*pskb, VLAN_HLEN);
590 (*pskb)->nh.raw += VLAN_HLEN;
593 nf_bridge = skb->nf_bridge;
594 if (skb->pkt_type == PACKET_OTHERHOST) {
595 skb->pkt_type = PACKET_HOST;
596 nf_bridge->mask |= BRNF_PKT_TYPE;
599 /* The physdev module checks on this */
600 nf_bridge->mask |= BRNF_BRIDGED;
601 nf_bridge->physoutdev = skb->dev;
603 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
604 br_nf_forward_finish);
606 return NF_STOLEN;
609 static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
610 const struct net_device *in,
611 const struct net_device *out,
612 int (*okfn)(struct sk_buff *))
614 struct sk_buff *skb = *pskb;
615 struct net_device **d = (struct net_device **)(skb->cb);
617 #ifdef CONFIG_SYSCTL
618 if (!brnf_call_arptables)
619 return NF_ACCEPT;
620 #endif
622 if (skb->protocol != htons(ETH_P_ARP)) {
623 if (!IS_VLAN_ARP(skb))
624 return NF_ACCEPT;
625 skb_pull(*pskb, VLAN_HLEN);
626 (*pskb)->nh.raw += VLAN_HLEN;
629 if (skb->nh.arph->ar_pln != 4) {
630 if (IS_VLAN_ARP(skb)) {
631 skb_push(*pskb, VLAN_HLEN);
632 (*pskb)->nh.raw -= VLAN_HLEN;
634 return NF_ACCEPT;
636 *d = (struct net_device *)in;
637 NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
638 (struct net_device *)out, br_nf_forward_finish);
640 return NF_STOLEN;
643 /* PF_BRIDGE/LOCAL_OUT ***********************************************/
644 static int br_nf_local_out_finish(struct sk_buff *skb)
646 if (skb->protocol == htons(ETH_P_8021Q)) {
647 skb_push(skb, VLAN_HLEN);
648 skb->nh.raw -= VLAN_HLEN;
651 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
652 br_forward_finish, NF_BR_PRI_FIRST + 1);
654 return 0;
657 /* This function sees both locally originated IP packets and forwarded
658 * IP packets (in both cases the destination device is a bridge
659 * device). It also sees bridged-and-DNAT'ed packets.
660 * To be able to filter on the physical bridge devices (with the physdev
661 * module), we steal packets destined to a bridge device away from the
662 * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
663 * when we have determined the real output device. This is done in here.
665 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
666 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
667 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
668 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
669 * will be executed.
670 * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
671 * this packet before, and so the packet was locally originated. We fake
672 * the PF_INET/LOCAL_OUT hook.
673 * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
674 * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
675 * even routed packets that didn't arrive on a bridge interface have their
676 * nf_bridge->physindev set. */
677 static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
678 const struct net_device *in,
679 const struct net_device *out,
680 int (*okfn)(struct sk_buff *))
682 struct net_device *realindev, *realoutdev;
683 struct sk_buff *skb = *pskb;
684 struct nf_bridge_info *nf_bridge;
685 int pf;
687 if (!skb->nf_bridge)
688 return NF_ACCEPT;
690 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
691 pf = PF_INET;
692 else
693 pf = PF_INET6;
695 #ifdef CONFIG_NETFILTER_DEBUG
696 /* Sometimes we get packets with NULL ->dst here (for example,
697 * running a dhcp client daemon triggers this). This should now
698 * be fixed, but let's keep the check around. */
699 if (skb->dst == NULL) {
700 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
701 return NF_ACCEPT;
703 #endif
705 nf_bridge = skb->nf_bridge;
706 nf_bridge->physoutdev = skb->dev;
707 realindev = nf_bridge->physindev;
709 /* Bridged, take PF_BRIDGE/FORWARD.
710 * (see big note in front of br_nf_pre_routing_finish) */
711 if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
712 if (nf_bridge->mask & BRNF_PKT_TYPE) {
713 skb->pkt_type = PACKET_OTHERHOST;
714 nf_bridge->mask ^= BRNF_PKT_TYPE;
716 if (skb->protocol == htons(ETH_P_8021Q)) {
717 skb_push(skb, VLAN_HLEN);
718 skb->nh.raw -= VLAN_HLEN;
721 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
722 skb->dev, br_forward_finish);
723 goto out;
725 realoutdev = bridge_parent(skb->dev);
726 if (!realoutdev)
727 return NF_DROP;
729 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
730 /* iptables should match -o br0.x */
731 if (nf_bridge->netoutdev)
732 realoutdev = nf_bridge->netoutdev;
733 #endif
734 if (skb->protocol == htons(ETH_P_8021Q)) {
735 skb_pull(skb, VLAN_HLEN);
736 (*pskb)->nh.raw += VLAN_HLEN;
738 /* IP forwarded traffic has a physindev, locally
739 * generated traffic hasn't. */
740 if (realindev != NULL) {
741 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT)) {
742 struct net_device *parent = bridge_parent(realindev);
743 if (parent)
744 realindev = parent;
747 NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
748 realoutdev, br_nf_local_out_finish,
749 NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
750 } else {
751 NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
752 realoutdev, br_nf_local_out_finish,
753 NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
756 out:
757 return NF_STOLEN;
760 static int br_nf_dev_queue_xmit(struct sk_buff *skb)
762 if (skb->protocol == htons(ETH_P_IP) &&
763 skb->len > skb->dev->mtu &&
764 !(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size))
765 return ip_fragment(skb, br_dev_queue_push_xmit);
766 else
767 return br_dev_queue_push_xmit(skb);
770 /* PF_BRIDGE/POST_ROUTING ********************************************/
771 static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
772 const struct net_device *in,
773 const struct net_device *out,
774 int (*okfn)(struct sk_buff *))
776 struct sk_buff *skb = *pskb;
777 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
778 struct net_device *realoutdev = bridge_parent(skb->dev);
779 int pf;
781 #ifdef CONFIG_NETFILTER_DEBUG
782 /* Be very paranoid. This probably won't happen anymore, but let's
783 * keep the check just to be sure... */
784 if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
785 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
786 "bad mac.raw pointer.");
787 goto print_error;
789 #endif
791 if (!nf_bridge)
792 return NF_ACCEPT;
794 if (!realoutdev)
795 return NF_DROP;
797 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
798 pf = PF_INET;
799 else
800 pf = PF_INET6;
802 #ifdef CONFIG_NETFILTER_DEBUG
803 if (skb->dst == NULL) {
804 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
805 goto print_error;
807 #endif
809 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
810 * about the value of skb->pkt_type. */
811 if (skb->pkt_type == PACKET_OTHERHOST) {
812 skb->pkt_type = PACKET_HOST;
813 nf_bridge->mask |= BRNF_PKT_TYPE;
816 if (skb->protocol == htons(ETH_P_8021Q)) {
817 skb_pull(skb, VLAN_HLEN);
818 skb->nh.raw += VLAN_HLEN;
821 nf_bridge_save_header(skb);
823 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
824 if (nf_bridge->netoutdev)
825 realoutdev = nf_bridge->netoutdev;
826 #endif
827 NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
828 br_nf_dev_queue_xmit);
830 return NF_STOLEN;
832 #ifdef CONFIG_NETFILTER_DEBUG
833 print_error:
834 if (skb->dev != NULL) {
835 printk("[%s]", skb->dev->name);
836 if (realoutdev)
837 printk("[%s]", realoutdev->name);
839 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
840 skb->data);
841 return NF_ACCEPT;
842 #endif
845 /* IP/SABOTAGE *****************************************************/
846 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
847 * for the second time. */
848 static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
849 const struct net_device *in,
850 const struct net_device *out,
851 int (*okfn)(struct sk_buff *))
853 if ((*pskb)->nf_bridge &&
854 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
855 return NF_STOP;
858 return NF_ACCEPT;
861 /* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
862 * and PF_INET(6)/POST_ROUTING until we have done the forwarding
863 * decision in the bridge code and have determined nf_bridge->physoutdev. */
864 static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
865 const struct net_device *in,
866 const struct net_device *out,
867 int (*okfn)(struct sk_buff *))
869 struct sk_buff *skb = *pskb;
871 if ((out->hard_start_xmit == br_dev_xmit &&
872 okfn != br_nf_forward_finish &&
873 okfn != br_nf_local_out_finish && okfn != br_nf_dev_queue_xmit)
874 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
875 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
876 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
877 #endif
879 struct nf_bridge_info *nf_bridge;
881 if (!skb->nf_bridge) {
882 #ifdef CONFIG_SYSCTL
883 /* This code is executed while in the IP(v6) stack,
884 the version should be 4 or 6. We can't use
885 skb->protocol because that isn't set on
886 PF_INET(6)/LOCAL_OUT. */
887 struct iphdr *ip = skb->nh.iph;
889 if (ip->version == 4 && !brnf_call_iptables)
890 return NF_ACCEPT;
891 else if (ip->version == 6 && !brnf_call_ip6tables)
892 return NF_ACCEPT;
893 #endif
894 if (hook == NF_IP_POST_ROUTING)
895 return NF_ACCEPT;
896 if (!nf_bridge_alloc(skb))
897 return NF_DROP;
900 nf_bridge = skb->nf_bridge;
902 /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
903 * will need the indev then. For a brouter, the real indev
904 * can be a bridge port, so we make sure br_nf_local_out()
905 * doesn't use the bridge parent of the indev by using
906 * the BRNF_DONT_TAKE_PARENT mask. */
907 if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
908 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
909 nf_bridge->physindev = (struct net_device *)in;
911 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
912 /* the iptables outdev is br0.x, not br0 */
913 if (out->priv_flags & IFF_802_1Q_VLAN)
914 nf_bridge->netoutdev = (struct net_device *)out;
915 #endif
916 return NF_STOP;
919 return NF_ACCEPT;
922 /* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
923 * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
924 * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
925 * ip_refrag() can return NF_STOLEN. */
926 static struct nf_hook_ops br_nf_ops[] = {
927 { .hook = br_nf_pre_routing,
928 .owner = THIS_MODULE,
929 .pf = PF_BRIDGE,
930 .hooknum = NF_BR_PRE_ROUTING,
931 .priority = NF_BR_PRI_BRNF, },
932 { .hook = br_nf_local_in,
933 .owner = THIS_MODULE,
934 .pf = PF_BRIDGE,
935 .hooknum = NF_BR_LOCAL_IN,
936 .priority = NF_BR_PRI_BRNF, },
937 { .hook = br_nf_forward_ip,
938 .owner = THIS_MODULE,
939 .pf = PF_BRIDGE,
940 .hooknum = NF_BR_FORWARD,
941 .priority = NF_BR_PRI_BRNF - 1, },
942 { .hook = br_nf_forward_arp,
943 .owner = THIS_MODULE,
944 .pf = PF_BRIDGE,
945 .hooknum = NF_BR_FORWARD,
946 .priority = NF_BR_PRI_BRNF, },
947 { .hook = br_nf_local_out,
948 .owner = THIS_MODULE,
949 .pf = PF_BRIDGE,
950 .hooknum = NF_BR_LOCAL_OUT,
951 .priority = NF_BR_PRI_FIRST, },
952 { .hook = br_nf_post_routing,
953 .owner = THIS_MODULE,
954 .pf = PF_BRIDGE,
955 .hooknum = NF_BR_POST_ROUTING,
956 .priority = NF_BR_PRI_LAST, },
957 { .hook = ip_sabotage_in,
958 .owner = THIS_MODULE,
959 .pf = PF_INET,
960 .hooknum = NF_IP_PRE_ROUTING,
961 .priority = NF_IP_PRI_FIRST, },
962 { .hook = ip_sabotage_in,
963 .owner = THIS_MODULE,
964 .pf = PF_INET6,
965 .hooknum = NF_IP6_PRE_ROUTING,
966 .priority = NF_IP6_PRI_FIRST, },
967 { .hook = ip_sabotage_out,
968 .owner = THIS_MODULE,
969 .pf = PF_INET,
970 .hooknum = NF_IP_FORWARD,
971 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
972 { .hook = ip_sabotage_out,
973 .owner = THIS_MODULE,
974 .pf = PF_INET6,
975 .hooknum = NF_IP6_FORWARD,
976 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
977 { .hook = ip_sabotage_out,
978 .owner = THIS_MODULE,
979 .pf = PF_INET,
980 .hooknum = NF_IP_LOCAL_OUT,
981 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
982 { .hook = ip_sabotage_out,
983 .owner = THIS_MODULE,
984 .pf = PF_INET6,
985 .hooknum = NF_IP6_LOCAL_OUT,
986 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
987 { .hook = ip_sabotage_out,
988 .owner = THIS_MODULE,
989 .pf = PF_INET,
990 .hooknum = NF_IP_POST_ROUTING,
991 .priority = NF_IP_PRI_FIRST, },
992 { .hook = ip_sabotage_out,
993 .owner = THIS_MODULE,
994 .pf = PF_INET6,
995 .hooknum = NF_IP6_POST_ROUTING,
996 .priority = NF_IP6_PRI_FIRST, },
999 #ifdef CONFIG_SYSCTL
1000 static
1001 int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
1002 void __user * buffer, size_t * lenp, loff_t * ppos)
1004 int ret;
1006 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
1008 if (write && *(int *)(ctl->data))
1009 *(int *)(ctl->data) = 1;
1010 return ret;
1013 static ctl_table brnf_table[] = {
1015 .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
1016 .procname = "bridge-nf-call-arptables",
1017 .data = &brnf_call_arptables,
1018 .maxlen = sizeof(int),
1019 .mode = 0644,
1020 .proc_handler = &brnf_sysctl_call_tables,
1023 .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
1024 .procname = "bridge-nf-call-iptables",
1025 .data = &brnf_call_iptables,
1026 .maxlen = sizeof(int),
1027 .mode = 0644,
1028 .proc_handler = &brnf_sysctl_call_tables,
1031 .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
1032 .procname = "bridge-nf-call-ip6tables",
1033 .data = &brnf_call_ip6tables,
1034 .maxlen = sizeof(int),
1035 .mode = 0644,
1036 .proc_handler = &brnf_sysctl_call_tables,
1039 .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
1040 .procname = "bridge-nf-filter-vlan-tagged",
1041 .data = &brnf_filter_vlan_tagged,
1042 .maxlen = sizeof(int),
1043 .mode = 0644,
1044 .proc_handler = &brnf_sysctl_call_tables,
1046 { .ctl_name = 0 }
1049 static ctl_table brnf_bridge_table[] = {
1051 .ctl_name = NET_BRIDGE,
1052 .procname = "bridge",
1053 .mode = 0555,
1054 .child = brnf_table,
1056 { .ctl_name = 0 }
1059 static ctl_table brnf_net_table[] = {
1061 .ctl_name = CTL_NET,
1062 .procname = "net",
1063 .mode = 0555,
1064 .child = brnf_bridge_table,
1066 { .ctl_name = 0 }
1068 #endif
1070 int br_netfilter_init(void)
1072 int i;
1074 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1075 int ret;
1077 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1078 continue;
1080 while (i--)
1081 nf_unregister_hook(&br_nf_ops[i]);
1083 return ret;
1086 #ifdef CONFIG_SYSCTL
1087 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1088 if (brnf_sysctl_header == NULL) {
1089 printk(KERN_WARNING
1090 "br_netfilter: can't register to sysctl.\n");
1091 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1092 nf_unregister_hook(&br_nf_ops[i]);
1093 return -EFAULT;
1095 #endif
1097 printk(KERN_NOTICE "Bridge firewalling registered\n");
1099 return 0;
1102 void br_netfilter_fini(void)
1104 int i;
1106 for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
1107 nf_unregister_hook(&br_nf_ops[i]);
1108 #ifdef CONFIG_SYSCTL
1109 unregister_sysctl_table(brnf_sysctl_header);
1110 #endif