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[IRDA]: fix drivers/net/irda/ali-ircc.c:ali_ircc_init()
[linux-block.git] / net / bridge / br_netfilter.c
CommitLineData
1da177e4
LT		 1/*
2 * Handle firewalling
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 * Bart De Schuymer (maintainer) <bdschuym@pandora.be>
8 *
9 * Changes:
10 * Apr 29 2003: physdev module support (bdschuym)
11 * Jun 19 2003: let arptables see bridged ARP traffic (bdschuym)
12 * Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge
13 * (bdschuym)
14 * Sep 01 2004: add IPv6 filtering (bdschuym)
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
20 *
21 * Lennert dedicates this file to Kerstin Wurdinger.
22 */
23
24#include <linux/module.h>
25#include <linux/kernel.h>
26#include <linux/ip.h>
27#include <linux/netdevice.h>
28#include <linux/skbuff.h>
14c85021 29#include <linux/if_arp.h>
1da177e4
LT		 30#include <linux/if_ether.h>
31#include <linux/if_vlan.h>
32#include <linux/netfilter_bridge.h>
33#include <linux/netfilter_ipv4.h>
34#include <linux/netfilter_ipv6.h>
35#include <linux/netfilter_arp.h>
36#include <linux/in_route.h>
14c85021 37
1da177e4
LT		 38#include <net/ip.h>
39#include <net/ipv6.h>
14c85021
ACM		 40#include <net/route.h>
41
1da177e4
LT		 42#include <asm/uaccess.h>
43#include <asm/checksum.h>
44#include "br_private.h"
45#ifdef CONFIG_SYSCTL
46#include <linux/sysctl.h>
47#endif
48
49#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
50 (skb->nf_bridge->data))->daddr.ipv4)
51#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
52#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
53
1da177e4
LT		 54#ifdef CONFIG_SYSCTL
55static struct ctl_table_header *brnf_sysctl_header;
56static int brnf_call_iptables = 1;
57static int brnf_call_ip6tables = 1;
58static int brnf_call_arptables = 1;
59static int brnf_filter_vlan_tagged = 1;
60#else
61#define brnf_filter_vlan_tagged 1
62#endif
63
8b42ec39
SH		 64static __be16 inline 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)
1da177e4
LT		 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. */
92static struct net_device __fake_net_device = {
93 .hard_header_len = ETH_HLEN
94};
95
96static 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},
42cf93cd 103 .flags = DST_NOXFRM,
1da177e4
LT		 104 }
105 },
106 .rt_flags = 0,
107};
108
5dce971a
SH		 109static 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}
1da177e4 115
fdeabdef
SH		 116static 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
125static inline void nf_bridge_save_header(struct sk_buff *skb)
126{
127 int header_size = 16;
128
129 if (skb->protocol == htons(ETH_P_8021Q))
130 header_size = 18;
131
132 memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
133}
134
1da177e4
LT		 135/* PF_BRIDGE/PRE_ROUTING *********************************************/
136/* Undo the changes made for ip6tables PREROUTING and continue the
137 * bridge PRE_ROUTING hook. */
138static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
139{
140 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
141
1da177e4
LT		 142 if (nf_bridge->mask & BRNF_PKT_TYPE) {
143 skb->pkt_type = PACKET_OTHERHOST;
144 nf_bridge->mask ^= BRNF_PKT_TYPE;
145 }
146 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
147
148 skb->dst = (struct dst_entry *)&__fake_rtable;
149 dst_hold(skb->dst);
150
151 skb->dev = nf_bridge->physindev;
f8a26028 152 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 153 skb_push(skb, VLAN_HLEN);
154 skb->nh.raw -= VLAN_HLEN;
155 }
156 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
157 br_handle_frame_finish, 1);
158
159 return 0;
160}
161
162static void __br_dnat_complain(void)
163{
164 static unsigned long last_complaint;
165
166 if (jiffies - last_complaint >= 5 * HZ) {
167 printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
789bc3e5 168 "forwarding to be enabled\n");
1da177e4
LT		 169 last_complaint = jiffies;
170 }
171}
172
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.
176 *
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.
184 *
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.
188 *
189 * Let us first consider the case that ip_route_input() succeeds:
190 *
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.
196 *
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.
200 *
201 * Let us now consider the case that ip_route_input() fails:
202 *
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.
209 *
210 * ip_route_input() will also fail if there is no route available.
211 * In that case we just drop the packet.
212 *
213 * --Lennert, 20020411
214 * --Bart, 20020416 (updated)
215 * --Bart, 20021007 (updated) */
216static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
217{
1da177e4
LT		 218 if (skb->pkt_type == PACKET_OTHERHOST) {
219 skb->pkt_type = PACKET_HOST;
220 skb->nf_bridge->mask |= BRNF_PKT_TYPE;
221 }
222 skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
223
224 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 225 if (!skb->dev)
226 kfree_skb(skb);
227 else {
f8a26028 228 if (skb->protocol == htons(ETH_P_8021Q)) {
5dce971a
SH		 229 skb_pull(skb, VLAN_HLEN);
230 skb->nh.raw += VLAN_HLEN;
231 }
232 skb->dst->output(skb);
1da177e4 233 }
1da177e4
LT		 234 return 0;
235}
236
237static int br_nf_pre_routing_finish(struct sk_buff *skb)
238{
239 struct net_device *dev = skb->dev;
240 struct iphdr *iph = skb->nh.iph;
241 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
242
1da177e4
LT		 243 if (nf_bridge->mask & BRNF_PKT_TYPE) {
244 skb->pkt_type = PACKET_OTHERHOST;
245 nf_bridge->mask ^= BRNF_PKT_TYPE;
246 }
247 nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
248
249 if (dnat_took_place(skb)) {
789bc3e5 250 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev)) {
1da177e4 251 struct rtable *rt;
789bc3e5
SH		 252 struct flowi fl = {
253 .nl_u = {
254 .ip4_u = {
255 .daddr = iph->daddr,
256 .saddr = 0,
257 .tos = RT_TOS(iph->tos) },
258 },
259 .proto = 0,
260 };
1da177e4
LT		 261
262 if (!ip_route_output_key(&rt, &fl)) {
1c011bed
BDS		 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) {
1da177e4
LT		 268 skb->dst = (struct dst_entry *)rt;
269 goto bridged_dnat;
270 }
271 __br_dnat_complain();
272 dst_release((struct dst_entry *)rt);
273 }
274 kfree_skb(skb);
275 return 0;
276 } else {
277 if (skb->dst->dev == dev) {
278bridged_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 ==
f8a26028 284 htons(ETH_P_8021Q)) {
1da177e4
LT		 285 skb_push(skb, VLAN_HLEN);
286 skb->nh.raw -= VLAN_HLEN;
287 }
288 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
289 skb, skb->dev, NULL,
290 br_nf_pre_routing_finish_bridge,
291 1);
292 return 0;
293 }
789bc3e5 294 memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
1da177e4
LT		 295 skb->pkt_type = PACKET_HOST;
296 }
297 } else {
298 skb->dst = (struct dst_entry *)&__fake_rtable;
299 dst_hold(skb->dst);
300 }
301
302 skb->dev = nf_bridge->physindev;
f8a26028 303 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 304 skb_push(skb, VLAN_HLEN);
305 skb->nh.raw -= VLAN_HLEN;
306 }
307 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
308 br_handle_frame_finish, 1);
309
310 return 0;
311}
312
313/* Some common code for IPv4/IPv6 */
5dce971a 314static struct net_device *setup_pre_routing(struct sk_buff *skb)
1da177e4
LT		 315{
316 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
317
318 if (skb->pkt_type == PACKET_OTHERHOST) {
319 skb->pkt_type = PACKET_HOST;
320 nf_bridge->mask |= BRNF_PKT_TYPE;
321 }
322
323 nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
324 nf_bridge->physindev = skb->dev;
325 skb->dev = bridge_parent(skb->dev);
5dce971a
SH		 326
327 return skb->dev;
1da177e4
LT		 328}
329
330/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
331static int check_hbh_len(struct sk_buff *skb)
332{
789bc3e5 333 unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
1da177e4
LT		 334 u32 pkt_len;
335 int off = raw - skb->nh.raw;
789bc3e5 336 int len = (raw[1] + 1) << 3;
1da177e4
LT		 337
338 if ((raw + len) - skb->data > skb_headlen(skb))
339 goto bad;
340
341 off += 2;
342 len -= 2;
343
344 while (len > 0) {
789bc3e5 345 int optlen = skb->nh.raw[off + 1] + 2;
1da177e4
LT		 346
347 switch (skb->nh.raw[off]) {
348 case IPV6_TLV_PAD0:
349 optlen = 1;
350 break;
351
352 case IPV6_TLV_PADN:
353 break;
354
355 case IPV6_TLV_JUMBO:
789bc3e5 356 if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
1da177e4 357 goto bad;
789bc3e5 358 pkt_len = ntohl(*(u32 *) (skb->nh.raw + off + 2));
b0366486
BDS		 359 if (pkt_len <= IPV6_MAXPLEN ||
360 skb->nh.ipv6h->payload_len)
361 goto bad;
1da177e4
LT		 362 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
363 goto bad;
b0366486 364 if (pskb_trim_rcsum(skb,
789bc3e5 365 pkt_len + sizeof(struct ipv6hdr)))
b0366486 366 goto bad;
1da177e4
LT		 367 break;
368 default:
369 if (optlen > len)
370 goto bad;
371 break;
372 }
373 off += optlen;
374 len -= optlen;
375 }
376 if (len == 0)
377 return 0;
378bad:
379 return -1;
380
381}
382
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. */
385static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
789bc3e5
SH		 386 struct sk_buff *skb,
387 const struct net_device *in,
388 const struct net_device *out,
389 int (*okfn)(struct sk_buff *))
1da177e4
LT		 390{
391 struct ipv6hdr *hdr;
392 u32 pkt_len;
1da177e4
LT		 393
394 if (skb->len < sizeof(struct ipv6hdr))
395 goto inhdr_error;
396
397 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
398 goto inhdr_error;
399
400 hdr = skb->nh.ipv6h;
401
402 if (hdr->version != 6)
403 goto inhdr_error;
404
405 pkt_len = ntohs(hdr->payload_len);
406
407 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
408 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
409 goto inhdr_error;
b38dfee3
HX		 410 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
411 goto inhdr_error;
1da177e4
LT		 412 }
413 if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
789bc3e5 414 goto inhdr_error;
1da177e4 415
789bc3e5 416 nf_bridge_put(skb->nf_bridge);
fdeabdef 417 if (!nf_bridge_alloc(skb))
1da177e4 418 return NF_DROP;
5dce971a
SH		 419 if (!setup_pre_routing(skb))
420 return NF_DROP;
1da177e4
LT		 421
422 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
423 br_nf_pre_routing_finish_ipv6);
424
425 return NF_STOLEN;
426
427inhdr_error:
428 return NF_DROP;
429}
430
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. */
437static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
ee02b3a6
SH		 438 const struct net_device *in,
439 const struct net_device *out,
440 int (*okfn)(struct sk_buff *))
1da177e4
LT		 441{
442 struct iphdr *iph;
443 __u32 len;
444 struct sk_buff *skb = *pskb;
1da177e4 445
8b42ec39 446 if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
1da177e4
LT		 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;
453
f8a26028 454 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 455 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 456 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 457 }
458 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
459 }
460#ifdef CONFIG_SYSCTL
461 if (!brnf_call_iptables)
462 return NF_ACCEPT;
463#endif
464
8b42ec39 465 if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
1da177e4
LT		 466 return NF_ACCEPT;
467
468 if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
469 goto out;
470
f8a26028 471 if (skb->protocol == htons(ETH_P_8021Q)) {
cbb042f9 472 skb_pull_rcsum(skb, VLAN_HLEN);
ee02b3a6 473 skb->nh.raw += VLAN_HLEN;
1da177e4
LT		 474 }
475
476 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
477 goto inhdr_error;
478
479 iph = skb->nh.iph;
480 if (iph->ihl < 5 || iph->version != 4)
481 goto inhdr_error;
482
789bc3e5 483 if (!pskb_may_pull(skb, 4 * iph->ihl))
1da177e4
LT		 484 goto inhdr_error;
485
486 iph = skb->nh.iph;
789bc3e5 487 if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
1da177e4
LT		 488 goto inhdr_error;
489
490 len = ntohs(iph->tot_len);
789bc3e5 491 if (skb->len < len || len < 4 * iph->ihl)
1da177e4
LT		 492 goto inhdr_error;
493
b38dfee3 494 pskb_trim_rcsum(skb, len);
1da177e4 495
789bc3e5 496 nf_bridge_put(skb->nf_bridge);
fdeabdef 497 if (!nf_bridge_alloc(skb))
1da177e4 498 return NF_DROP;
5dce971a
SH		 499 if (!setup_pre_routing(skb))
500 return NF_DROP;
1da177e4
LT		 501 store_orig_dstaddr(skb);
502
503 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
504 br_nf_pre_routing_finish);
505
506 return NF_STOLEN;
507
508inhdr_error:
789bc3e5 509// IP_INC_STATS_BH(IpInHdrErrors);
1da177e4
LT		 510out:
511 return NF_DROP;
512}
513
514
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. */
522static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 523 const struct net_device *in,
524 const struct net_device *out,
525 int (*okfn)(struct sk_buff *))
1da177e4
LT		 526{
527 struct sk_buff *skb = *pskb;
528
529 if (skb->dst == (struct dst_entry *)&__fake_rtable) {
530 dst_release(skb->dst);
531 skb->dst = NULL;
532 }
533
534 return NF_ACCEPT;
535}
536
1da177e4
LT		 537/* PF_BRIDGE/FORWARD *************************************************/
538static int br_nf_forward_finish(struct sk_buff *skb)
539{
540 struct nf_bridge_info *nf_bridge = skb->nf_bridge;
541 struct net_device *in;
1da177e4 542
8b42ec39 543 if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
1da177e4
LT		 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;
548 }
549 } else {
550 in = *((struct net_device **)(skb->cb));
551 }
f8a26028 552 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 553 skb_push(skb, VLAN_HLEN);
554 skb->nh.raw -= VLAN_HLEN;
555 }
556 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
789bc3e5 557 skb->dev, br_forward_finish, 1);
1da177e4
LT		 558 return 0;
559}
560
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. */
566static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 567 const struct net_device *in,
568 const struct net_device *out,
569 int (*okfn)(struct sk_buff *))
1da177e4
LT		 570{
571 struct sk_buff *skb = *pskb;
572 struct nf_bridge_info *nf_bridge;
5dce971a 573 struct net_device *parent;
1da177e4
LT		 574 int pf;
575
576 if (!skb->nf_bridge)
577 return NF_ACCEPT;
578
5dce971a
SH		 579 parent = bridge_parent(out);
580 if (!parent)
581 return NF_DROP;
582
8b42ec39 583 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 584 pf = PF_INET;
585 else
586 pf = PF_INET6;
587
f8a26028 588 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 589 skb_pull(*pskb, VLAN_HLEN);
590 (*pskb)->nh.raw += VLAN_HLEN;
591 }
592
1da177e4
LT		 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;
597 }
598
599 /* The physdev module checks on this */
600 nf_bridge->mask |= BRNF_BRIDGED;
601 nf_bridge->physoutdev = skb->dev;
602
5dce971a
SH		 603 NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
604 br_nf_forward_finish);
1da177e4
LT		 605
606 return NF_STOLEN;
607}
608
609static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 610 const struct net_device *in,
611 const struct net_device *out,
612 int (*okfn)(struct sk_buff *))
1da177e4
LT		 613{
614 struct sk_buff *skb = *pskb;
1da177e4
LT		 615 struct net_device **d = (struct net_device **)(skb->cb);
616
617#ifdef CONFIG_SYSCTL
618 if (!brnf_call_arptables)
619 return NF_ACCEPT;
620#endif
621
f8a26028 622 if (skb->protocol != htons(ETH_P_ARP)) {
8b42ec39 623 if (!IS_VLAN_ARP(skb))
1da177e4
LT		 624 return NF_ACCEPT;
625 skb_pull(*pskb, VLAN_HLEN);
626 (*pskb)->nh.raw += VLAN_HLEN;
627 }
628
1da177e4 629 if (skb->nh.arph->ar_pln != 4) {
8b42ec39 630 if (IS_VLAN_ARP(skb)) {
1da177e4
LT		 631 skb_push(*pskb, VLAN_HLEN);
632 (*pskb)->nh.raw -= VLAN_HLEN;
633 }
634 return NF_ACCEPT;
635 }
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);
639
640 return NF_STOLEN;
641}
642
1da177e4
LT		 643/* PF_BRIDGE/LOCAL_OUT ***********************************************/
644static int br_nf_local_out_finish(struct sk_buff *skb)
645{
f8a26028 646 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 647 skb_push(skb, VLAN_HLEN);
648 skb->nh.raw -= VLAN_HLEN;
649 }
650
651 NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
789bc3e5 652 br_forward_finish, NF_BR_PRI_FIRST + 1);
1da177e4
LT		 653
654 return 0;
655}
656
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.
664 *
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. */
677static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 678 const struct net_device *in,
679 const struct net_device *out,
680 int (*okfn)(struct sk_buff *))
1da177e4
LT		 681{
682 struct net_device *realindev, *realoutdev;
683 struct sk_buff *skb = *pskb;
684 struct nf_bridge_info *nf_bridge;
1da177e4
LT		 685 int pf;
686
687 if (!skb->nf_bridge)
688 return NF_ACCEPT;
689
8b42ec39 690 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 691 pf = PF_INET;
692 else
693 pf = PF_INET6;
694
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;
702 }
703#endif
704
705 nf_bridge = skb->nf_bridge;
706 nf_bridge->physoutdev = skb->dev;
707 realindev = nf_bridge->physindev;
708
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;
715 }
f8a26028 716 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 717 skb_push(skb, VLAN_HLEN);
718 skb->nh.raw -= VLAN_HLEN;
719 }
720
721 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
722 skb->dev, br_forward_finish);
723 goto out;
724 }
725 realoutdev = bridge_parent(skb->dev);
5dce971a
SH		 726 if (!realoutdev)
727 return NF_DROP;
1da177e4
LT		 728
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
f8a26028 734 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 735 skb_pull(skb, VLAN_HLEN);
736 (*pskb)->nh.raw += VLAN_HLEN;
737 }
738 /* IP forwarded traffic has a physindev, locally
739 * generated traffic hasn't. */
740 if (realindev != NULL) {
789bc3e5 741 if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT)) {
5dce971a
SH		 742 struct net_device *parent = bridge_parent(realindev);
743 if (parent)
744 realindev = parent;
745 }
1da177e4
LT		 746
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 {
1da177e4
LT		 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);
754 }
755
756out:
757 return NF_STOLEN;
758}
759
2e2f7aef
PM		 760static int br_nf_dev_queue_xmit(struct sk_buff *skb)
761{
762 if (skb->protocol == htons(ETH_P_IP) &&
763 skb->len > skb->dev->mtu &&
7967168c 764 !skb_shinfo(skb)->gso_size)
2e2f7aef
PM		 765 return ip_fragment(skb, br_dev_queue_push_xmit);
766 else
767 return br_dev_queue_push_xmit(skb);
768}
1da177e4
LT		 769
770/* PF_BRIDGE/POST_ROUTING ********************************************/
771static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 772 const struct net_device *in,
773 const struct net_device *out,
774 int (*okfn)(struct sk_buff *))
1da177e4
LT		 775{
776 struct sk_buff *skb = *pskb;
777 struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
1da177e4
LT		 778 struct net_device *realoutdev = bridge_parent(skb->dev);
779 int pf;
780
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: "
789bc3e5 786 "bad mac.raw pointer.");
1da177e4
LT		 787 goto print_error;
788 }
789#endif
790
791 if (!nf_bridge)
792 return NF_ACCEPT;
793
5dce971a
SH		 794 if (!realoutdev)
795 return NF_DROP;
796
8b42ec39 797 if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
1da177e4
LT		 798 pf = PF_INET;
799 else
800 pf = PF_INET6;
801
802#ifdef CONFIG_NETFILTER_DEBUG
803 if (skb->dst == NULL) {
804 printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
805 goto print_error;
806 }
1da177e4
LT		 807#endif
808
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;
814 }
815
f8a26028 816 if (skb->protocol == htons(ETH_P_8021Q)) {
1da177e4
LT		 817 skb_pull(skb, VLAN_HLEN);
818 skb->nh.raw += VLAN_HLEN;
819 }
820
821 nf_bridge_save_header(skb);
822
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,
2e2f7aef 828 br_nf_dev_queue_xmit);
1da177e4
LT		 829
830 return NF_STOLEN;
831
832#ifdef CONFIG_NETFILTER_DEBUG
833print_error:
834 if (skb->dev != NULL) {
835 printk("[%s]", skb->dev->name);
178a3259
SH		 836 if (realoutdev)
837 printk("[%s]", realoutdev->name);
1da177e4
LT		 838 }
839 printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
789bc3e5 840 skb->data);
1da177e4
LT		 841 return NF_ACCEPT;
842#endif
843}
844
1da177e4
LT		 845/* IP/SABOTAGE *****************************************************/
846/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
847 * for the second time. */
848static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 849 const struct net_device *in,
850 const struct net_device *out,
851 int (*okfn)(struct sk_buff *))
1da177e4
LT		 852{
853 if ((*pskb)->nf_bridge &&
854 !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
855 return NF_STOP;
856 }
857
858 return NF_ACCEPT;
859}
860
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. */
864static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
789bc3e5
SH		 865 const struct net_device *in,
866 const struct net_device *out,
867 int (*okfn)(struct sk_buff *))
1da177e4
LT		 868{
869 struct sk_buff *skb = *pskb;
870
871 if ((out->hard_start_xmit == br_dev_xmit &&
789bc3e5 872 okfn != br_nf_forward_finish &&
2e2f7aef 873 okfn != br_nf_local_out_finish && okfn != br_nf_dev_queue_xmit)
1da177e4
LT		 874#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
875 || ((out->priv_flags & IFF_802_1Q_VLAN) &&
789bc3e5 876 VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
1da177e4
LT		 877#endif
878 ) {
879 struct nf_bridge_info *nf_bridge;
880
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;
888
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;
898 }
899
900 nf_bridge = skb->nf_bridge;
901
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) {
9666dae5 908 nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
1da177e4
LT		 909 nf_bridge->physindev = (struct net_device *)in;
910 }
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;
917 }
918
919 return NF_ACCEPT;
920}
921
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. */
926static 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, },
997};
998
999#ifdef CONFIG_SYSCTL
1000static
789bc3e5
SH		 1001int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
1002 void __user * buffer, size_t * lenp, loff_t * ppos)
1da177e4
LT		 1003{
1004 int ret;
1005
1006 ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
1007
1008 if (write && *(int *)(ctl->data))
1009 *(int *)(ctl->data) = 1;
1010 return ret;
1011}
1012
1013static ctl_table brnf_table[] = {
1014 {
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,
1021 },
1022 {
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,
1029 },
1030 {
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,
1037 },
1038 {
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,
1045 },
1046 { .ctl_name = 0 }
1047};
1048
1049static ctl_table brnf_bridge_table[] = {
1050 {
1051 .ctl_name = NET_BRIDGE,
1052 .procname = "bridge",
1053 .mode = 0555,
1054 .child = brnf_table,
1055 },
1056 { .ctl_name = 0 }
1057};
1058
1059static ctl_table brnf_net_table[] = {
1060 {
1061 .ctl_name = CTL_NET,
1062 .procname = "net",
1063 .mode = 0555,
1064 .child = brnf_bridge_table,
1065 },
1066 { .ctl_name = 0 }
1067};
1068#endif
1069
1070int br_netfilter_init(void)
1071{
1072 int i;
1073
1074 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
1075 int ret;
1076
1077 if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
1078 continue;
1079
1080 while (i--)
1081 nf_unregister_hook(&br_nf_ops[i]);
1082
1083 return ret;
1084 }
1085
1086#ifdef CONFIG_SYSCTL
1087 brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
1088 if (brnf_sysctl_header == NULL) {
789bc3e5
SH		 1089 printk(KERN_WARNING
1090 "br_netfilter: can't register to sysctl.\n");
1da177e4
LT		 1091 for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
1092 nf_unregister_hook(&br_nf_ops[i]);
1093 return -EFAULT;
1094 }
1095#endif
1096
1097 printk(KERN_NOTICE "Bridge firewalling registered\n");
1098
1099 return 0;
1100}
1101
1102void br_netfilter_fini(void)
1103{
1104 int i;
1105
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
1111}
Linux 6.x block layer and io_uring tree(s)