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[BRIDGE-NF]: Fix bridge-nf ipv6 length check
[GitHub/mt8127/android_kernel_alcatel_ttab.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>
29#include <linux/if_ether.h>
30#include <linux/if_vlan.h>
31#include <linux/netfilter_bridge.h>
32#include <linux/netfilter_ipv4.h>
33#include <linux/netfilter_ipv6.h>
34#include <linux/netfilter_arp.h>
35#include <linux/in_route.h>
36#include <net/ip.h>
37#include <net/ipv6.h>
38#include <asm/uaccess.h>
39#include <asm/checksum.h>
40#include "br_private.h"
41#ifdef CONFIG_SYSCTL
42#include <linux/sysctl.h>
43#endif
44
45#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
46 (skb->nf_bridge->data))->daddr.ipv4)
47#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
48#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
49
50#define has_bridge_parent(device) ((device)->br_port != NULL)
51#define bridge_parent(device) ((device)->br_port->br->dev)
52
53#ifdef CONFIG_SYSCTL
54static struct ctl_table_header *brnf_sysctl_header;
55static int brnf_call_iptables = 1;
56static int brnf_call_ip6tables = 1;
57static int brnf_call_arptables = 1;
58static int brnf_filter_vlan_tagged = 1;
59#else
60#define brnf_filter_vlan_tagged 1
61#endif
62
63#define IS_VLAN_IP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
64 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IP) && \
65 brnf_filter_vlan_tagged)
66#define IS_VLAN_IPV6 (skb->protocol == __constant_htons(ETH_P_8021Q) && \
67 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IPV6) && \
68 brnf_filter_vlan_tagged)
69#define IS_VLAN_ARP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
70 hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_ARP) && \
71 brnf_filter_vlan_tagged)
72
73/* We need these fake structures to make netfilter happy --
74 * lots of places assume that skb->dst != NULL, which isn't
75 * all that unreasonable.
76 *
77 * Currently, we fill in the PMTU entry because netfilter
78 * refragmentation needs it, and the rt_flags entry because
79 * ipt_REJECT needs it. Future netfilter modules might
80 * require us to fill additional fields. */
81static struct net_device __fake_net_device = {
82 .hard_header_len = ETH_HLEN
83};
84
85static struct rtable __fake_rtable = {
86 .u = {
87 .dst = {
88 .__refcnt = ATOMIC_INIT(1),
89 .dev = &__fake_net_device,
90 .path = &__fake_rtable.u.dst,
91 .metrics = {[RTAX_MTU - 1] = 1500},
92 }
93 },
94 .rt_flags = 0,
95};
96
97
98/* PF_BRIDGE/PRE_ROUTING *********************************************/
99/* Undo the changes made for ip6tables PREROUTING and continue the
100 * bridge PRE_ROUTING hook. */
101static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
102{
103 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
104
1da177e4
LT		 105 if (nf_bridge->mask & BRNF_PKT_TYPE) {
106 skb->pkt_type = PACKET_OTHERHOST;
107 nf_bridge->mask ^= BRNF_PKT_TYPE;
108 }
109 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
110
111 skb->dst = (struct dst_entry *)&__fake_rtable;
112 dst_hold(skb->dst);
113
114 skb->dev = nf_bridge->physindev;
115 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
116 skb_push(skb, VLAN_HLEN);
117 skb->nh.raw -= VLAN_HLEN;
118 }
119 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
120 br_handle_frame_finish, 1);
121
122 return 0;
123}
124
125static void __br_dnat_complain(void)
126{
127 static unsigned long last_complaint;
128
129 if (jiffies - last_complaint >= 5 * HZ) {
130 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
131 "forwarding to be enabled\n");
132 last_complaint = jiffies;
133 }
134}
135
136/* This requires some explaining. If DNAT has taken place,
137 * we will need to fix up the destination Ethernet address,
138 * and this is a tricky process.
139 *
140 * There are two cases to consider:
141 * 1. The packet was DNAT'ed to a device in the same bridge
142 * port group as it was received on. We can still bridge
143 * the packet.
144 * 2. The packet was DNAT'ed to a different device, either
145 * a non-bridged device or another bridge port group.
146 * The packet will need to be routed.
147 *
148 * The correct way of distinguishing between these two cases is to
149 * call ip_route_input() and to look at skb->dst->dev, which is
150 * changed to the destination device if ip_route_input() succeeds.
151 *
152 * Let us first consider the case that ip_route_input() succeeds:
153 *
154 * If skb->dst->dev equals the logical bridge device the packet
155 * came in on, we can consider this bridging. We then call
156 * skb->dst->output() which will make the packet enter br_nf_local_out()
157 * not much later. In that function it is assured that the iptables
158 * FORWARD chain is traversed for the packet.
159 *
160 * Otherwise, the packet is considered to be routed and we just
161 * change the destination MAC address so that the packet will
162 * later be passed up to the IP stack to be routed.
163 *
164 * Let us now consider the case that ip_route_input() fails:
165 *
166 * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
167 * will fail, while __ip_route_output_key() will return success. The source
168 * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
169 * thinks we're handling a locally generated packet and won't care
170 * if IP forwarding is allowed. We send a warning message to the users's
171 * log telling her to put IP forwarding on.
172 *
173 * ip_route_input() will also fail if there is no route available.
174 * In that case we just drop the packet.
175 *
176 * --Lennert, 20020411
177 * --Bart, 20020416 (updated)
178 * --Bart, 20021007 (updated) */
179static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
180{
1da177e4
LT		 181 if (skb->pkt_type == PACKET_OTHERHOST) {
182 skb->pkt_type = PACKET_HOST;
183 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
184 }
185 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
186
187 skb->dev = bridge_parent(skb->dev);
188 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
189 skb_pull(skb, VLAN_HLEN);
190 skb->nh.raw += VLAN_HLEN;
191 }
192 skb->dst->output(skb);
193 return 0;
194}
195
196static int br_nf_pre_routing_finish(struct sk_buff *skb)
197{
198 struct net_device *dev = skb->dev;
199 struct iphdr *iph = skb->nh.iph;
200 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
201
1da177e4
LT		 202 if (nf_bridge->mask & BRNF_PKT_TYPE) {
203 skb->pkt_type = PACKET_OTHERHOST;
204 nf_bridge->mask ^= BRNF_PKT_TYPE;
205 }
206 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
207
208 if (dnat_took_place(skb)) {
209 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
210 dev)) {
211 struct rtable *rt;
212 struct flowi fl = { .nl_u =
213 { .ip4_u = { .daddr = iph->daddr, .saddr = 0 ,
214 .tos = RT_TOS(iph->tos)} }, .proto = 0};
215
216 if (!ip_route_output_key(&rt, &fl)) {
1c011bed
BDS		 217 /* - Bridged-and-DNAT'ed traffic doesn't
218 * require ip_forwarding.
219 * - Deal with redirected traffic. */
220 if (((struct dst_entry *)rt)->dev == dev ||
221 rt->rt_type == RTN_LOCAL) {
1da177e4
LT		 222 skb->dst = (struct dst_entry *)rt;
223 goto bridged_dnat;
224 }
225 __br_dnat_complain();
226 dst_release((struct dst_entry *)rt);
227 }
228 kfree_skb(skb);
229 return 0;
230 } else {
231 if (skb->dst->dev == dev) {
232bridged_dnat:
233 /* Tell br_nf_local_out this is a
234 * bridged frame */
235 nf_bridge->mask |= BRNF_BRIDGED_DNAT;
236 skb->dev = nf_bridge->physindev;
237 if (skb->protocol ==
238 __constant_htons(ETH_P_8021Q)) {
239 skb_push(skb, VLAN_HLEN);
240 skb->nh.raw -= VLAN_HLEN;
241 }
242 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
243 skb, skb->dev, NULL,
244 br_nf_pre_routing_finish_bridge,
245 1);
246 return 0;
247 }
248 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr,
249 ETH_ALEN);
250 skb->pkt_type = PACKET_HOST;
251 }
252 } else {
253 skb->dst = (struct dst_entry *)&__fake_rtable;
254 dst_hold(skb->dst);
255 }
256
257 skb->dev = nf_bridge->physindev;
258 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
259 skb_push(skb, VLAN_HLEN);
260 skb->nh.raw -= VLAN_HLEN;
261 }
262 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
263 br_handle_frame_finish, 1);
264
265 return 0;
266}
267
268/* Some common code for IPv4/IPv6 */
269static void setup_pre_routing(struct sk_buff *skb)
270{
271 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
272
273 if (skb->pkt_type == PACKET_OTHERHOST) {
274 skb->pkt_type = PACKET_HOST;
275 nf_bridge->mask |= BRNF_PKT_TYPE;
276 }
277
278 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
279 nf_bridge->physindev = skb->dev;
280 skb->dev = bridge_parent(skb->dev);
281}
282
283/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
284static int check_hbh_len(struct sk_buff *skb)
285{
286 unsigned char *raw = (u8*)(skb->nh.ipv6h+1);
287 u32 pkt_len;
288 int off = raw - skb->nh.raw;
289 int len = (raw[1]+1)<<3;
290
291 if ((raw + len) - skb->data > skb_headlen(skb))
292 goto bad;
293
294 off += 2;
295 len -= 2;
296
297 while (len > 0) {
b0366486 298 int optlen = skb->nh.raw[off+1]+2;
1da177e4
LT		 299
300 switch (skb->nh.raw[off]) {
301 case IPV6_TLV_PAD0:
302 optlen = 1;
303 break;
304
305 case IPV6_TLV_PADN:
306 break;
307
308 case IPV6_TLV_JUMBO:
309 if (skb->nh.raw[off+1] != 4 || (off&3) != 2)
310 goto bad;
1da177e4 311 pkt_len = ntohl(*(u32*)(skb->nh.raw+off+2));
b0366486
BDS		 312 if (pkt_len <= IPV6_MAXPLEN ||
313 skb->nh.ipv6h->payload_len)
314 goto bad;
1da177e4
LT		 315 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
316 goto bad;
b0366486
BDS		 317 if (pskb_trim_rcsum(skb,
318 pkt_len+sizeof(struct ipv6hdr)))
319 goto bad;
1da177e4
LT		 320 break;
321 default:
322 if (optlen > len)
323 goto bad;
324 break;
325 }
326 off += optlen;
327 len -= optlen;
328 }
329 if (len == 0)
330 return 0;
331bad:
332 return -1;
333
334}
335
336/* Replicate the checks that IPv6 does on packet reception and pass the packet
337 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
338static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
339 struct sk_buff *skb, const struct net_device *in,
340 const struct net_device *out, int (*okfn)(struct sk_buff *))
341{
342 struct ipv6hdr *hdr;
343 u32 pkt_len;
344 struct nf_bridge_info *nf_bridge;
345
346 if (skb->len < sizeof(struct ipv6hdr))
347 goto inhdr_error;
348
349 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
350 goto inhdr_error;
351
352 hdr = skb->nh.ipv6h;
353
354 if (hdr->version != 6)
355 goto inhdr_error;
356
357 pkt_len = ntohs(hdr->payload_len);
358
359 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
360 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
361 goto inhdr_error;
362 if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
363 if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr)))
364 goto inhdr_error;
365 if (skb->ip_summed == CHECKSUM_HW)
366 skb->ip_summed = CHECKSUM_NONE;
367 }
368 }
369 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
370 goto inhdr_error;
371
1da177e4
LT		 372 if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
373 return NF_DROP;
374 setup_pre_routing(skb);
375
376 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
377 br_nf_pre_routing_finish_ipv6);
378
379 return NF_STOLEN;
380
381inhdr_error:
382 return NF_DROP;
383}
384
385/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
386 * Replicate the checks that IPv4 does on packet reception.
387 * Set skb->dev to the bridge device (i.e. parent of the
388 * receiving device) to make netfilter happy, the REDIRECT
389 * target in particular. Save the original destination IP
390 * address to be able to detect DNAT afterwards. */
391static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
392 const struct net_device *in, const struct net_device *out,
393 int (*okfn)(struct sk_buff *))
394{
395 struct iphdr *iph;
396 __u32 len;
397 struct sk_buff *skb = *pskb;
398 struct nf_bridge_info *nf_bridge;
399 struct vlan_ethhdr *hdr = vlan_eth_hdr(*pskb);
400
401 if (skb->protocol == __constant_htons(ETH_P_IPV6) || IS_VLAN_IPV6) {
402#ifdef CONFIG_SYSCTL
403 if (!brnf_call_ip6tables)
404 return NF_ACCEPT;
405#endif
406 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
407 goto out;
408
409 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
410 skb_pull(skb, VLAN_HLEN);
411 (skb)->nh.raw += VLAN_HLEN;
412 }
413 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
414 }
415#ifdef CONFIG_SYSCTL
416 if (!brnf_call_iptables)
417 return NF_ACCEPT;
418#endif
419
420 if (skb->protocol != __constant_htons(ETH_P_IP) && !IS_VLAN_IP)
421 return NF_ACCEPT;
422
423 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
424 goto out;
425
426 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
427 skb_pull(skb, VLAN_HLEN);
428 (skb)->nh.raw += VLAN_HLEN;
429 }
430
431 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
432 goto inhdr_error;
433
434 iph = skb->nh.iph;
435 if (iph->ihl < 5 || iph->version != 4)
436 goto inhdr_error;
437
438 if (!pskb_may_pull(skb, 4*iph->ihl))
439 goto inhdr_error;
440
441 iph = skb->nh.iph;
442 if (ip_fast_csum((__u8 *)iph, iph->ihl) != 0)
443 goto inhdr_error;
444
445 len = ntohs(iph->tot_len);
446 if (skb->len < len || len < 4*iph->ihl)
447 goto inhdr_error;
448
449 if (skb->len > len) {
450 __pskb_trim(skb, len);
451 if (skb->ip_summed == CHECKSUM_HW)
452 skb->ip_summed = CHECKSUM_NONE;
453 }
454
1da177e4
LT		 455 if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
456 return NF_DROP;
457 setup_pre_routing(skb);
458 store_orig_dstaddr(skb);
459
460 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
461 br_nf_pre_routing_finish);
462
463 return NF_STOLEN;
464
465inhdr_error:
466// IP_INC_STATS_BH(IpInHdrErrors);
467out:
468 return NF_DROP;
469}
470
471
472/* PF_BRIDGE/LOCAL_IN ************************************************/
473/* The packet is locally destined, which requires a real
474 * dst_entry, so detach the fake one. On the way up, the
475 * packet would pass through PRE_ROUTING again (which already
476 * took place when the packet entered the bridge), but we
477 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
478 * prevent this from happening. */
479static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
480 const struct net_device *in, const struct net_device *out,
481 int (*okfn)(struct sk_buff *))
482{
483 struct sk_buff *skb = *pskb;
484
485 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
486 dst_release(skb->dst);
487 skb->dst = NULL;
488 }
489
490 return NF_ACCEPT;
491}
492
493
494/* PF_BRIDGE/FORWARD *************************************************/
495static int br_nf_forward_finish(struct sk_buff *skb)
496{
497 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
498 struct net_device *in;
499 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
500
1da177e4
LT		 501 if (skb->protocol != __constant_htons(ETH_P_ARP) && !IS_VLAN_ARP) {
502 in = nf_bridge->physindev;
503 if (nf_bridge->mask & BRNF_PKT_TYPE) {
504 skb->pkt_type = PACKET_OTHERHOST;
505 nf_bridge->mask ^= BRNF_PKT_TYPE;
506 }
507 } else {
508 in = *((struct net_device **)(skb->cb));
509 }
510 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
511 skb_push(skb, VLAN_HLEN);
512 skb->nh.raw -= VLAN_HLEN;
513 }
514 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
515 skb->dev, br_forward_finish, 1);
516 return 0;
517}
518
519/* This is the 'purely bridged' case. For IP, we pass the packet to
520 * netfilter with indev and outdev set to the bridge device,
521 * but we are still able to filter on the 'real' indev/outdev
522 * because of the physdev module. For ARP, indev and outdev are the
523 * bridge ports. */
524static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
525 const struct net_device *in, const struct net_device *out,
526 int (*okfn)(struct sk_buff *))
527{
528 struct sk_buff *skb = *pskb;
529 struct nf_bridge_info *nf_bridge;
530 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
531 int pf;
532
533 if (!skb->nf_bridge)
534 return NF_ACCEPT;
535
536 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
537 pf = PF_INET;
538 else
539 pf = PF_INET6;
540
541 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
542 skb_pull(*pskb, VLAN_HLEN);
543 (*pskb)->nh.raw += VLAN_HLEN;
544 }
545
1da177e4
LT		 546 nf_bridge = skb->nf_bridge;
547 if (skb->pkt_type == PACKET_OTHERHOST) {
548 skb->pkt_type = PACKET_HOST;
549 nf_bridge->mask |= BRNF_PKT_TYPE;
550 }
551
552 /* The physdev module checks on this */
553 nf_bridge->mask |= BRNF_BRIDGED;
554 nf_bridge->physoutdev = skb->dev;
555
556 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in),
557 bridge_parent(out), br_nf_forward_finish);
558
559 return NF_STOLEN;
560}
561
562static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
563 const struct net_device *in, const struct net_device *out,
564 int (*okfn)(struct sk_buff *))
565{
566 struct sk_buff *skb = *pskb;
567 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
568 struct net_device **d = (struct net_device **)(skb->cb);
569
570#ifdef CONFIG_SYSCTL
571 if (!brnf_call_arptables)
572 return NF_ACCEPT;
573#endif
574
575 if (skb->protocol != __constant_htons(ETH_P_ARP)) {
576 if (!IS_VLAN_ARP)
577 return NF_ACCEPT;
578 skb_pull(*pskb, VLAN_HLEN);
579 (*pskb)->nh.raw += VLAN_HLEN;
580 }
581
1da177e4
LT		 582 if (skb->nh.arph->ar_pln != 4) {
583 if (IS_VLAN_ARP) {
584 skb_push(*pskb, VLAN_HLEN);
585 (*pskb)->nh.raw -= VLAN_HLEN;
586 }
587 return NF_ACCEPT;
588 }
589 *d = (struct net_device *)in;
590 NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
591 (struct net_device *)out, br_nf_forward_finish);
592
593 return NF_STOLEN;
594}
595
596
597/* PF_BRIDGE/LOCAL_OUT ***********************************************/
598static int br_nf_local_out_finish(struct sk_buff *skb)
599{
1da177e4
LT		 600 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
601 skb_push(skb, VLAN_HLEN);
602 skb->nh.raw -= VLAN_HLEN;
603 }
604
605 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
606 br_forward_finish, NF_BR_PRI_FIRST + 1);
607
608 return 0;
609}
610
611/* This function sees both locally originated IP packets and forwarded
612 * IP packets (in both cases the destination device is a bridge
613 * device). It also sees bridged-and-DNAT'ed packets.
614 * To be able to filter on the physical bridge devices (with the physdev
615 * module), we steal packets destined to a bridge device away from the
616 * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
617 * when we have determined the real output device. This is done in here.
618 *
619 * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
620 * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
621 * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
622 * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
623 * will be executed.
624 * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
625 * this packet before, and so the packet was locally originated. We fake
626 * the PF_INET/LOCAL_OUT hook.
627 * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
628 * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
629 * even routed packets that didn't arrive on a bridge interface have their
630 * nf_bridge->physindev set. */
631static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
632 const struct net_device *in, const struct net_device *out,
633 int (*okfn)(struct sk_buff *))
634{
635 struct net_device *realindev, *realoutdev;
636 struct sk_buff *skb = *pskb;
637 struct nf_bridge_info *nf_bridge;
638 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
639 int pf;
640
641 if (!skb->nf_bridge)
642 return NF_ACCEPT;
643
644 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
645 pf = PF_INET;
646 else
647 pf = PF_INET6;
648
649#ifdef CONFIG_NETFILTER_DEBUG
650 /* Sometimes we get packets with NULL ->dst here (for example,
651 * running a dhcp client daemon triggers this). This should now
652 * be fixed, but let's keep the check around. */
653 if (skb->dst == NULL) {
654 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
655 return NF_ACCEPT;
656 }
657#endif
658
659 nf_bridge = skb->nf_bridge;
660 nf_bridge->physoutdev = skb->dev;
661 realindev = nf_bridge->physindev;
662
663 /* Bridged, take PF_BRIDGE/FORWARD.
664 * (see big note in front of br_nf_pre_routing_finish) */
665 if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
666 if (nf_bridge->mask & BRNF_PKT_TYPE) {
667 skb->pkt_type = PACKET_OTHERHOST;
668 nf_bridge->mask ^= BRNF_PKT_TYPE;
669 }
670 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
671 skb_push(skb, VLAN_HLEN);
672 skb->nh.raw -= VLAN_HLEN;
673 }
674
675 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
676 skb->dev, br_forward_finish);
677 goto out;
678 }
679 realoutdev = bridge_parent(skb->dev);
680
681#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
682 /* iptables should match -o br0.x */
683 if (nf_bridge->netoutdev)
684 realoutdev = nf_bridge->netoutdev;
685#endif
686 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
687 skb_pull(skb, VLAN_HLEN);
688 (*pskb)->nh.raw += VLAN_HLEN;
689 }
690 /* IP forwarded traffic has a physindev, locally
691 * generated traffic hasn't. */
692 if (realindev != NULL) {
693 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT) &&
694 has_bridge_parent(realindev))
695 realindev = bridge_parent(realindev);
696
697 NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
698 realoutdev, br_nf_local_out_finish,
699 NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
700 } else {
1da177e4
LT		 701 NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
702 realoutdev, br_nf_local_out_finish,
703 NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
704 }
705
706out:
707 return NF_STOLEN;
708}
709
710
711/* PF_BRIDGE/POST_ROUTING ********************************************/
712static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
713 const struct net_device *in, const struct net_device *out,
714 int (*okfn)(struct sk_buff *))
715{
716 struct sk_buff *skb = *pskb;
717 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
718 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
719 struct net_device *realoutdev = bridge_parent(skb->dev);
720 int pf;
721
722#ifdef CONFIG_NETFILTER_DEBUG
723 /* Be very paranoid. This probably won't happen anymore, but let's
724 * keep the check just to be sure... */
725 if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
726 printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
727 "bad mac.raw pointer.");
728 goto print_error;
729 }
730#endif
731
732 if (!nf_bridge)
733 return NF_ACCEPT;
734
735 if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
736 pf = PF_INET;
737 else
738 pf = PF_INET6;
739
740#ifdef CONFIG_NETFILTER_DEBUG
741 if (skb->dst == NULL) {
742 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
743 goto print_error;
744 }
1da177e4
LT		 745#endif
746
747 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
748 * about the value of skb->pkt_type. */
749 if (skb->pkt_type == PACKET_OTHERHOST) {
750 skb->pkt_type = PACKET_HOST;
751 nf_bridge->mask |= BRNF_PKT_TYPE;
752 }
753
754 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
755 skb_pull(skb, VLAN_HLEN);
756 skb->nh.raw += VLAN_HLEN;
757 }
758
759 nf_bridge_save_header(skb);
760
761#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
762 if (nf_bridge->netoutdev)
763 realoutdev = nf_bridge->netoutdev;
764#endif
765 NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
766 br_dev_queue_push_xmit);
767
768 return NF_STOLEN;
769
770#ifdef CONFIG_NETFILTER_DEBUG
771print_error:
772 if (skb->dev != NULL) {
773 printk("[%s]", skb->dev->name);
774 if (has_bridge_parent(skb->dev))
775 printk("[%s]", bridge_parent(skb->dev)->name);
776 }
777 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
778 skb->data);
779 return NF_ACCEPT;
780#endif
781}
782
783
784/* IP/SABOTAGE *****************************************************/
785/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
786 * for the second time. */
787static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
788 const struct net_device *in, const struct net_device *out,
789 int (*okfn)(struct sk_buff *))
790{
791 if ((*pskb)->nf_bridge &&
792 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
793 return NF_STOP;
794 }
795
796 return NF_ACCEPT;
797}
798
799/* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
800 * and PF_INET(6)/POST_ROUTING until we have done the forwarding
801 * decision in the bridge code and have determined nf_bridge->physoutdev. */
802static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
803 const struct net_device *in, const struct net_device *out,
804 int (*okfn)(struct sk_buff *))
805{
806 struct sk_buff *skb = *pskb;
807
808 if ((out->hard_start_xmit == br_dev_xmit &&
809 okfn != br_nf_forward_finish &&
810 okfn != br_nf_local_out_finish &&
811 okfn != br_dev_queue_push_xmit)
812#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
813 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
814 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
815#endif
816 ) {
817 struct nf_bridge_info *nf_bridge;
818
819 if (!skb->nf_bridge) {
820#ifdef CONFIG_SYSCTL
821 /* This code is executed while in the IP(v6) stack,
822 the version should be 4 or 6. We can't use
823 skb->protocol because that isn't set on
824 PF_INET(6)/LOCAL_OUT. */
825 struct iphdr *ip = skb->nh.iph;
826
827 if (ip->version == 4 && !brnf_call_iptables)
828 return NF_ACCEPT;
829 else if (ip->version == 6 && !brnf_call_ip6tables)
830 return NF_ACCEPT;
831#endif
832 if (hook == NF_IP_POST_ROUTING)
833 return NF_ACCEPT;
834 if (!nf_bridge_alloc(skb))
835 return NF_DROP;
836 }
837
838 nf_bridge = skb->nf_bridge;
839
840 /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
841 * will need the indev then. For a brouter, the real indev
842 * can be a bridge port, so we make sure br_nf_local_out()
843 * doesn't use the bridge parent of the indev by using
844 * the BRNF_DONT_TAKE_PARENT mask. */
845 if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
9666dae5 846 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
1da177e4
LT		 847 nf_bridge->physindev = (struct net_device *)in;
848 }
849#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
850 /* the iptables outdev is br0.x, not br0 */
851 if (out->priv_flags & IFF_802_1Q_VLAN)
852 nf_bridge->netoutdev = (struct net_device *)out;
853#endif
854 return NF_STOP;
855 }
856
857 return NF_ACCEPT;
858}
859
860/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
861 * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
862 * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
863 * ip_refrag() can return NF_STOLEN. */
864static struct nf_hook_ops br_nf_ops[] = {
865 { .hook = br_nf_pre_routing,
866 .owner = THIS_MODULE,
867 .pf = PF_BRIDGE,
868 .hooknum = NF_BR_PRE_ROUTING,
869 .priority = NF_BR_PRI_BRNF, },
870 { .hook = br_nf_local_in,
871 .owner = THIS_MODULE,
872 .pf = PF_BRIDGE,
873 .hooknum = NF_BR_LOCAL_IN,
874 .priority = NF_BR_PRI_BRNF, },
875 { .hook = br_nf_forward_ip,
876 .owner = THIS_MODULE,
877 .pf = PF_BRIDGE,
878 .hooknum = NF_BR_FORWARD,
879 .priority = NF_BR_PRI_BRNF - 1, },
880 { .hook = br_nf_forward_arp,
881 .owner = THIS_MODULE,
882 .pf = PF_BRIDGE,
883 .hooknum = NF_BR_FORWARD,
884 .priority = NF_BR_PRI_BRNF, },
885 { .hook = br_nf_local_out,
886 .owner = THIS_MODULE,
887 .pf = PF_BRIDGE,
888 .hooknum = NF_BR_LOCAL_OUT,
889 .priority = NF_BR_PRI_FIRST, },
890 { .hook = br_nf_post_routing,
891 .owner = THIS_MODULE,
892 .pf = PF_BRIDGE,
893 .hooknum = NF_BR_POST_ROUTING,
894 .priority = NF_BR_PRI_LAST, },
895 { .hook = ip_sabotage_in,
896 .owner = THIS_MODULE,
897 .pf = PF_INET,
898 .hooknum = NF_IP_PRE_ROUTING,
899 .priority = NF_IP_PRI_FIRST, },
900 { .hook = ip_sabotage_in,
901 .owner = THIS_MODULE,
902 .pf = PF_INET6,
903 .hooknum = NF_IP6_PRE_ROUTING,
904 .priority = NF_IP6_PRI_FIRST, },
905 { .hook = ip_sabotage_out,
906 .owner = THIS_MODULE,
907 .pf = PF_INET,
908 .hooknum = NF_IP_FORWARD,
909 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
910 { .hook = ip_sabotage_out,
911 .owner = THIS_MODULE,
912 .pf = PF_INET6,
913 .hooknum = NF_IP6_FORWARD,
914 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
915 { .hook = ip_sabotage_out,
916 .owner = THIS_MODULE,
917 .pf = PF_INET,
918 .hooknum = NF_IP_LOCAL_OUT,
919 .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
920 { .hook = ip_sabotage_out,
921 .owner = THIS_MODULE,
922 .pf = PF_INET6,
923 .hooknum = NF_IP6_LOCAL_OUT,
924 .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
925 { .hook = ip_sabotage_out,
926 .owner = THIS_MODULE,
927 .pf = PF_INET,
928 .hooknum = NF_IP_POST_ROUTING,
929 .priority = NF_IP_PRI_FIRST, },
930 { .hook = ip_sabotage_out,
931 .owner = THIS_MODULE,
932 .pf = PF_INET6,
933 .hooknum = NF_IP6_POST_ROUTING,
934 .priority = NF_IP6_PRI_FIRST, },
935};
936
937#ifdef CONFIG_SYSCTL
938static
939int brnf_sysctl_call_tables(ctl_table *ctl, int write, struct file * filp,
940 void __user *buffer, size_t *lenp, loff_t *ppos)
941{
942 int ret;
943
944 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
945
946 if (write && *(int *)(ctl->data))
947 *(int *)(ctl->data) = 1;
948 return ret;
949}
950
951static ctl_table brnf_table[] = {
952 {
953 .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
954 .procname = "bridge-nf-call-arptables",
955 .data = &brnf_call_arptables,
956 .maxlen = sizeof(int),
957 .mode = 0644,
958 .proc_handler = &brnf_sysctl_call_tables,
959 },
960 {
961 .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
962 .procname = "bridge-nf-call-iptables",
963 .data = &brnf_call_iptables,
964 .maxlen = sizeof(int),
965 .mode = 0644,
966 .proc_handler = &brnf_sysctl_call_tables,
967 },
968 {
969 .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
970 .procname = "bridge-nf-call-ip6tables",
971 .data = &brnf_call_ip6tables,
972 .maxlen = sizeof(int),
973 .mode = 0644,
974 .proc_handler = &brnf_sysctl_call_tables,
975 },
976 {
977 .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
978 .procname = "bridge-nf-filter-vlan-tagged",
979 .data = &brnf_filter_vlan_tagged,
980 .maxlen = sizeof(int),
981 .mode = 0644,
982 .proc_handler = &brnf_sysctl_call_tables,
983 },
984 { .ctl_name = 0 }
985};
986
987static ctl_table brnf_bridge_table[] = {
988 {
989 .ctl_name = NET_BRIDGE,
990 .procname = "bridge",
991 .mode = 0555,
992 .child = brnf_table,
993 },
994 { .ctl_name = 0 }
995};
996
997static ctl_table brnf_net_table[] = {
998 {
999 .ctl_name = CTL_NET,
1000 .procname = "net",
1001 .mode = 0555,
1002 .child = brnf_bridge_table,
1003 },
1004 { .ctl_name = 0 }
1005};
1006#endif
1007
1008int br_netfilter_init(void)
1009{
1010 int i;
1011
1012 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1013 int ret;
1014
1015 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1016 continue;
1017
1018 while (i--)
1019 nf_unregister_hook(&br_nf_ops[i]);
1020
1021 return ret;
1022 }
1023
1024#ifdef CONFIG_SYSCTL
1025 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1026 if (brnf_sysctl_header == NULL) {
1027 printk(KERN_WARNING "br_netfilter: can't register to sysctl.\n");
1028 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1029 nf_unregister_hook(&br_nf_ops[i]);
1030 return -EFAULT;
1031 }
1032#endif
1033
1034 printk(KERN_NOTICE "Bridge firewalling registered\n");
1035
1036 return 0;
1037}
1038
1039void br_netfilter_fini(void)
1040{
1041 int i;
1042
1043 for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
1044 nf_unregister_hook(&br_nf_ops[i]);
1045#ifdef CONFIG_SYSCTL
1046 unregister_sysctl_table(brnf_sysctl_header);
1047#endif
1048}
kernel source for telekom puls (alcatel/mediatek)