3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
7 * Bart De Schuymer <bdschuym@pandora.be>
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
14 * Lennert dedicates this file to Kerstin Wurdinger.
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/slab.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <linux/if_arp.h>
24 #include <linux/if_ether.h>
25 #include <linux/if_vlan.h>
26 #include <linux/if_pppox.h>
27 #include <linux/ppp_defs.h>
28 #include <linux/netfilter_bridge.h>
29 #include <linux/netfilter_ipv4.h>
30 #include <linux/netfilter_ipv6.h>
31 #include <linux/netfilter_arp.h>
32 #include <linux/in_route.h>
33 #include <linux/rculist.h>
34 #include <linux/inetdevice.h>
38 #include <net/addrconf.h>
39 #include <net/route.h>
40 #include <net/netfilter/br_netfilter.h>
41 #include <net/netns/generic.h>
43 #include <linux/uaccess.h>
44 #include "br_private.h"
46 #include <linux/sysctl.h>
49 static unsigned int brnf_net_id __read_mostly
;
56 static struct ctl_table_header
*brnf_sysctl_header
;
57 static int brnf_call_iptables __read_mostly
= 1;
58 static int brnf_call_ip6tables __read_mostly
= 1;
59 static int brnf_call_arptables __read_mostly
= 1;
60 static int brnf_filter_vlan_tagged __read_mostly
;
61 static int brnf_filter_pppoe_tagged __read_mostly
;
62 static int brnf_pass_vlan_indev __read_mostly
;
64 #define brnf_call_iptables 1
65 #define brnf_call_ip6tables 1
66 #define brnf_call_arptables 1
67 #define brnf_filter_vlan_tagged 0
68 #define brnf_filter_pppoe_tagged 0
69 #define brnf_pass_vlan_indev 0
73 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
75 #define IS_IPV6(skb) \
76 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
79 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
81 static inline __be16
vlan_proto(const struct sk_buff
*skb
)
83 if (skb_vlan_tag_present(skb
))
85 else if (skb
->protocol
== htons(ETH_P_8021Q
))
86 return vlan_eth_hdr(skb
)->h_vlan_encapsulated_proto
;
91 #define IS_VLAN_IP(skb) \
92 (vlan_proto(skb) == htons(ETH_P_IP) && \
93 brnf_filter_vlan_tagged)
95 #define IS_VLAN_IPV6(skb) \
96 (vlan_proto(skb) == htons(ETH_P_IPV6) && \
97 brnf_filter_vlan_tagged)
99 #define IS_VLAN_ARP(skb) \
100 (vlan_proto(skb) == htons(ETH_P_ARP) && \
101 brnf_filter_vlan_tagged)
103 static inline __be16
pppoe_proto(const struct sk_buff
*skb
)
105 return *((__be16
*)(skb_mac_header(skb
) + ETH_HLEN
+
106 sizeof(struct pppoe_hdr
)));
109 #define IS_PPPOE_IP(skb) \
110 (skb->protocol == htons(ETH_P_PPP_SES) && \
111 pppoe_proto(skb) == htons(PPP_IP) && \
112 brnf_filter_pppoe_tagged)
114 #define IS_PPPOE_IPV6(skb) \
115 (skb->protocol == htons(ETH_P_PPP_SES) && \
116 pppoe_proto(skb) == htons(PPP_IPV6) && \
117 brnf_filter_pppoe_tagged)
119 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
120 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
122 struct brnf_frag_data
{
123 char mac
[NF_BRIDGE_MAX_MAC_HEADER_LENGTH
];
130 static DEFINE_PER_CPU(struct brnf_frag_data
, brnf_frag_data_storage
);
132 static void nf_bridge_info_free(struct sk_buff
*skb
)
134 if (skb
->nf_bridge
) {
135 nf_bridge_put(skb
->nf_bridge
);
136 skb
->nf_bridge
= NULL
;
140 static inline struct net_device
*bridge_parent(const struct net_device
*dev
)
142 struct net_bridge_port
*port
;
144 port
= br_port_get_rcu(dev
);
145 return port
? port
->br
->dev
: NULL
;
148 static inline struct nf_bridge_info
*nf_bridge_unshare(struct sk_buff
*skb
)
150 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
152 if (refcount_read(&nf_bridge
->use
) > 1) {
153 struct nf_bridge_info
*tmp
= nf_bridge_alloc(skb
);
156 memcpy(tmp
, nf_bridge
, sizeof(struct nf_bridge_info
));
157 refcount_set(&tmp
->use
, 1);
159 nf_bridge_put(nf_bridge
);
165 unsigned int nf_bridge_encap_header_len(const struct sk_buff
*skb
)
167 switch (skb
->protocol
) {
168 case __cpu_to_be16(ETH_P_8021Q
):
170 case __cpu_to_be16(ETH_P_PPP_SES
):
171 return PPPOE_SES_HLEN
;
177 static inline void nf_bridge_pull_encap_header(struct sk_buff
*skb
)
179 unsigned int len
= nf_bridge_encap_header_len(skb
);
182 skb
->network_header
+= len
;
185 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff
*skb
)
187 unsigned int len
= nf_bridge_encap_header_len(skb
);
189 skb_pull_rcsum(skb
, len
);
190 skb
->network_header
+= len
;
193 /* When handing a packet over to the IP layer
194 * check whether we have a skb that is in the
198 static int br_validate_ipv4(struct net
*net
, struct sk_buff
*skb
)
200 const struct iphdr
*iph
;
203 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
208 /* Basic sanity checks */
209 if (iph
->ihl
< 5 || iph
->version
!= 4)
212 if (!pskb_may_pull(skb
, iph
->ihl
*4))
216 if (unlikely(ip_fast_csum((u8
*)iph
, iph
->ihl
)))
219 len
= ntohs(iph
->tot_len
);
220 if (skb
->len
< len
) {
221 __IP_INC_STATS(net
, IPSTATS_MIB_INTRUNCATEDPKTS
);
223 } else if (len
< (iph
->ihl
*4))
226 if (pskb_trim_rcsum(skb
, len
)) {
227 __IP_INC_STATS(net
, IPSTATS_MIB_INDISCARDS
);
231 memset(IPCB(skb
), 0, sizeof(struct inet_skb_parm
));
232 /* We should really parse IP options here but until
233 * somebody who actually uses IP options complains to
234 * us we'll just silently ignore the options because
240 __IP_INC_STATS(net
, IPSTATS_MIB_INHDRERRORS
);
245 void nf_bridge_update_protocol(struct sk_buff
*skb
)
247 switch (skb
->nf_bridge
->orig_proto
) {
248 case BRNF_PROTO_8021Q
:
249 skb
->protocol
= htons(ETH_P_8021Q
);
251 case BRNF_PROTO_PPPOE
:
252 skb
->protocol
= htons(ETH_P_PPP_SES
);
254 case BRNF_PROTO_UNCHANGED
:
259 /* Obtain the correct destination MAC address, while preserving the original
260 * source MAC address. If we already know this address, we just copy it. If we
261 * don't, we use the neighbour framework to find out. In both cases, we make
262 * sure that br_handle_frame_finish() is called afterwards.
264 int br_nf_pre_routing_finish_bridge(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
266 struct neighbour
*neigh
;
267 struct dst_entry
*dst
;
269 skb
->dev
= bridge_parent(skb
->dev
);
273 neigh
= dst_neigh_lookup_skb(dst
, skb
);
275 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
278 if ((neigh
->nud_state
& NUD_CONNECTED
) && neigh
->hh
.hh_len
) {
279 neigh_hh_bridge(&neigh
->hh
, skb
);
280 skb
->dev
= nf_bridge
->physindev
;
281 ret
= br_handle_frame_finish(net
, sk
, skb
);
283 /* the neighbour function below overwrites the complete
284 * MAC header, so we save the Ethernet source address and
287 skb_copy_from_linear_data_offset(skb
,
288 -(ETH_HLEN
-ETH_ALEN
),
289 nf_bridge
->neigh_header
,
291 /* tell br_dev_xmit to continue with forwarding */
292 nf_bridge
->bridged_dnat
= 1;
293 /* FIXME Need to refragment */
294 ret
= neigh
->output(neigh
, skb
);
296 neigh_release(neigh
);
305 br_nf_ipv4_daddr_was_changed(const struct sk_buff
*skb
,
306 const struct nf_bridge_info
*nf_bridge
)
308 return ip_hdr(skb
)->daddr
!= nf_bridge
->ipv4_daddr
;
311 /* This requires some explaining. If DNAT has taken place,
312 * we will need to fix up the destination Ethernet address.
313 * This is also true when SNAT takes place (for the reply direction).
315 * There are two cases to consider:
316 * 1. The packet was DNAT'ed to a device in the same bridge
317 * port group as it was received on. We can still bridge
319 * 2. The packet was DNAT'ed to a different device, either
320 * a non-bridged device or another bridge port group.
321 * The packet will need to be routed.
323 * The correct way of distinguishing between these two cases is to
324 * call ip_route_input() and to look at skb->dst->dev, which is
325 * changed to the destination device if ip_route_input() succeeds.
327 * Let's first consider the case that ip_route_input() succeeds:
329 * If the output device equals the logical bridge device the packet
330 * came in on, we can consider this bridging. The corresponding MAC
331 * address will be obtained in br_nf_pre_routing_finish_bridge.
332 * Otherwise, the packet is considered to be routed and we just
333 * change the destination MAC address so that the packet will
334 * later be passed up to the IP stack to be routed. For a redirected
335 * packet, ip_route_input() will give back the localhost as output device,
336 * which differs from the bridge device.
338 * Let's now consider the case that ip_route_input() fails:
340 * This can be because the destination address is martian, in which case
341 * the packet will be dropped.
342 * If IP forwarding is disabled, ip_route_input() will fail, while
343 * ip_route_output_key() can return success. The source
344 * address for ip_route_output_key() is set to zero, so ip_route_output_key()
345 * thinks we're handling a locally generated packet and won't care
346 * if IP forwarding is enabled. If the output device equals the logical bridge
347 * device, we proceed as if ip_route_input() succeeded. If it differs from the
348 * logical bridge port or if ip_route_output_key() fails we drop the packet.
350 static int br_nf_pre_routing_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
352 struct net_device
*dev
= skb
->dev
;
353 struct iphdr
*iph
= ip_hdr(skb
);
354 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
358 nf_bridge
->frag_max_size
= IPCB(skb
)->frag_max_size
;
360 if (nf_bridge
->pkt_otherhost
) {
361 skb
->pkt_type
= PACKET_OTHERHOST
;
362 nf_bridge
->pkt_otherhost
= false;
364 nf_bridge
->in_prerouting
= 0;
365 if (br_nf_ipv4_daddr_was_changed(skb
, nf_bridge
)) {
366 if ((err
= ip_route_input(skb
, iph
->daddr
, iph
->saddr
, iph
->tos
, dev
))) {
367 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
369 /* If err equals -EHOSTUNREACH the error is due to a
370 * martian destination or due to the fact that
371 * forwarding is disabled. For most martian packets,
372 * ip_route_output_key() will fail. It won't fail for 2 types of
373 * martian destinations: loopback destinations and destination
374 * 0.0.0.0. In both cases the packet will be dropped because the
375 * destination is the loopback device and not the bridge. */
376 if (err
!= -EHOSTUNREACH
|| !in_dev
|| IN_DEV_FORWARD(in_dev
))
379 rt
= ip_route_output(net
, iph
->daddr
, 0,
380 RT_TOS(iph
->tos
), 0);
382 /* - Bridged-and-DNAT'ed traffic doesn't
383 * require ip_forwarding. */
384 if (rt
->dst
.dev
== dev
) {
385 skb_dst_set(skb
, &rt
->dst
);
394 if (skb_dst(skb
)->dev
== dev
) {
396 skb
->dev
= nf_bridge
->physindev
;
397 nf_bridge_update_protocol(skb
);
398 nf_bridge_push_encap_header(skb
);
399 br_nf_hook_thresh(NF_BR_PRE_ROUTING
,
400 net
, sk
, skb
, skb
->dev
,
402 br_nf_pre_routing_finish_bridge
);
405 ether_addr_copy(eth_hdr(skb
)->h_dest
, dev
->dev_addr
);
406 skb
->pkt_type
= PACKET_HOST
;
409 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
414 skb_dst_set_noref(skb
, &rt
->dst
);
417 skb
->dev
= nf_bridge
->physindev
;
418 nf_bridge_update_protocol(skb
);
419 nf_bridge_push_encap_header(skb
);
420 br_nf_hook_thresh(NF_BR_PRE_ROUTING
, net
, sk
, skb
, skb
->dev
, NULL
,
421 br_handle_frame_finish
);
425 static struct net_device
*brnf_get_logical_dev(struct sk_buff
*skb
, const struct net_device
*dev
)
427 struct net_device
*vlan
, *br
;
429 br
= bridge_parent(dev
);
430 if (brnf_pass_vlan_indev
== 0 || !skb_vlan_tag_present(skb
))
433 vlan
= __vlan_find_dev_deep_rcu(br
, skb
->vlan_proto
,
434 skb_vlan_tag_get(skb
) & VLAN_VID_MASK
);
436 return vlan
? vlan
: br
;
439 /* Some common code for IPv4/IPv6 */
440 struct net_device
*setup_pre_routing(struct sk_buff
*skb
)
442 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
444 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
445 skb
->pkt_type
= PACKET_HOST
;
446 nf_bridge
->pkt_otherhost
= true;
449 nf_bridge
->in_prerouting
= 1;
450 nf_bridge
->physindev
= skb
->dev
;
451 skb
->dev
= brnf_get_logical_dev(skb
, skb
->dev
);
453 if (skb
->protocol
== htons(ETH_P_8021Q
))
454 nf_bridge
->orig_proto
= BRNF_PROTO_8021Q
;
455 else if (skb
->protocol
== htons(ETH_P_PPP_SES
))
456 nf_bridge
->orig_proto
= BRNF_PROTO_PPPOE
;
458 /* Must drop socket now because of tproxy. */
463 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
464 * Replicate the checks that IPv4 does on packet reception.
465 * Set skb->dev to the bridge device (i.e. parent of the
466 * receiving device) to make netfilter happy, the REDIRECT
467 * target in particular. Save the original destination IP
468 * address to be able to detect DNAT afterwards. */
469 static unsigned int br_nf_pre_routing(void *priv
,
471 const struct nf_hook_state
*state
)
473 struct nf_bridge_info
*nf_bridge
;
474 struct net_bridge_port
*p
;
475 struct net_bridge
*br
;
476 __u32 len
= nf_bridge_encap_header_len(skb
);
478 if (unlikely(!pskb_may_pull(skb
, len
)))
481 p
= br_port_get_rcu(state
->in
);
486 if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
)) {
487 if (!brnf_call_ip6tables
&& !br
->nf_call_ip6tables
)
490 nf_bridge_pull_encap_header_rcsum(skb
);
491 return br_nf_pre_routing_ipv6(priv
, skb
, state
);
494 if (!brnf_call_iptables
&& !br
->nf_call_iptables
)
497 if (!IS_IP(skb
) && !IS_VLAN_IP(skb
) && !IS_PPPOE_IP(skb
))
500 nf_bridge_pull_encap_header_rcsum(skb
);
502 if (br_validate_ipv4(state
->net
, skb
))
505 nf_bridge_put(skb
->nf_bridge
);
506 if (!nf_bridge_alloc(skb
))
508 if (!setup_pre_routing(skb
))
511 nf_bridge
= nf_bridge_info_get(skb
);
512 nf_bridge
->ipv4_daddr
= ip_hdr(skb
)->daddr
;
514 skb
->protocol
= htons(ETH_P_IP
);
516 NF_HOOK(NFPROTO_IPV4
, NF_INET_PRE_ROUTING
, state
->net
, state
->sk
, skb
,
518 br_nf_pre_routing_finish
);
524 /* PF_BRIDGE/FORWARD *************************************************/
525 static int br_nf_forward_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
527 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
528 struct net_device
*in
;
530 if (!IS_ARP(skb
) && !IS_VLAN_ARP(skb
)) {
532 if (skb
->protocol
== htons(ETH_P_IP
))
533 nf_bridge
->frag_max_size
= IPCB(skb
)->frag_max_size
;
535 if (skb
->protocol
== htons(ETH_P_IPV6
))
536 nf_bridge
->frag_max_size
= IP6CB(skb
)->frag_max_size
;
538 in
= nf_bridge
->physindev
;
539 if (nf_bridge
->pkt_otherhost
) {
540 skb
->pkt_type
= PACKET_OTHERHOST
;
541 nf_bridge
->pkt_otherhost
= false;
543 nf_bridge_update_protocol(skb
);
545 in
= *((struct net_device
**)(skb
->cb
));
547 nf_bridge_push_encap_header(skb
);
549 br_nf_hook_thresh(NF_BR_FORWARD
, net
, sk
, skb
, in
, skb
->dev
,
555 /* This is the 'purely bridged' case. For IP, we pass the packet to
556 * netfilter with indev and outdev set to the bridge device,
557 * but we are still able to filter on the 'real' indev/outdev
558 * because of the physdev module. For ARP, indev and outdev are the
560 static unsigned int br_nf_forward_ip(void *priv
,
562 const struct nf_hook_state
*state
)
564 struct nf_bridge_info
*nf_bridge
;
565 struct net_device
*parent
;
571 /* Need exclusive nf_bridge_info since we might have multiple
572 * different physoutdevs. */
573 if (!nf_bridge_unshare(skb
))
576 nf_bridge
= nf_bridge_info_get(skb
);
580 parent
= bridge_parent(state
->out
);
584 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
586 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
591 nf_bridge_pull_encap_header(skb
);
593 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
594 skb
->pkt_type
= PACKET_HOST
;
595 nf_bridge
->pkt_otherhost
= true;
598 if (pf
== NFPROTO_IPV4
) {
599 if (br_validate_ipv4(state
->net
, skb
))
601 IPCB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
604 if (pf
== NFPROTO_IPV6
) {
605 if (br_validate_ipv6(state
->net
, skb
))
607 IP6CB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
610 nf_bridge
->physoutdev
= skb
->dev
;
611 if (pf
== NFPROTO_IPV4
)
612 skb
->protocol
= htons(ETH_P_IP
);
614 skb
->protocol
= htons(ETH_P_IPV6
);
616 NF_HOOK(pf
, NF_INET_FORWARD
, state
->net
, NULL
, skb
,
617 brnf_get_logical_dev(skb
, state
->in
),
618 parent
, br_nf_forward_finish
);
623 static unsigned int br_nf_forward_arp(void *priv
,
625 const struct nf_hook_state
*state
)
627 struct net_bridge_port
*p
;
628 struct net_bridge
*br
;
629 struct net_device
**d
= (struct net_device
**)(skb
->cb
);
631 p
= br_port_get_rcu(state
->out
);
636 if (!brnf_call_arptables
&& !br
->nf_call_arptables
)
640 if (!IS_VLAN_ARP(skb
))
642 nf_bridge_pull_encap_header(skb
);
645 if (arp_hdr(skb
)->ar_pln
!= 4) {
646 if (IS_VLAN_ARP(skb
))
647 nf_bridge_push_encap_header(skb
);
651 NF_HOOK(NFPROTO_ARP
, NF_ARP_FORWARD
, state
->net
, state
->sk
, skb
,
652 state
->in
, state
->out
, br_nf_forward_finish
);
657 static int br_nf_push_frag_xmit(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
659 struct brnf_frag_data
*data
;
662 data
= this_cpu_ptr(&brnf_frag_data_storage
);
663 err
= skb_cow_head(skb
, data
->size
);
670 if (data
->vlan_tci
) {
671 skb
->vlan_tci
= data
->vlan_tci
;
672 skb
->vlan_proto
= data
->vlan_proto
;
675 skb_copy_to_linear_data_offset(skb
, -data
->size
, data
->mac
, data
->size
);
676 __skb_push(skb
, data
->encap_size
);
678 nf_bridge_info_free(skb
);
679 return br_dev_queue_push_xmit(net
, sk
, skb
);
683 br_nf_ip_fragment(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
,
684 int (*output
)(struct net
*, struct sock
*, struct sk_buff
*))
686 unsigned int mtu
= ip_skb_dst_mtu(sk
, skb
);
687 struct iphdr
*iph
= ip_hdr(skb
);
689 if (unlikely(((iph
->frag_off
& htons(IP_DF
)) && !skb
->ignore_df
) ||
690 (IPCB(skb
)->frag_max_size
&&
691 IPCB(skb
)->frag_max_size
> mtu
))) {
692 IP_INC_STATS(net
, IPSTATS_MIB_FRAGFAILS
);
697 return ip_do_fragment(net
, sk
, skb
, output
);
700 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff
*skb
)
702 if (skb
->nf_bridge
->orig_proto
== BRNF_PROTO_PPPOE
)
703 return PPPOE_SES_HLEN
;
707 static int br_nf_dev_queue_xmit(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
709 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
710 unsigned int mtu
, mtu_reserved
;
712 mtu_reserved
= nf_bridge_mtu_reduction(skb
);
715 if (nf_bridge
->frag_max_size
&& nf_bridge
->frag_max_size
< mtu
)
716 mtu
= nf_bridge
->frag_max_size
;
718 if (skb_is_gso(skb
) || skb
->len
+ mtu_reserved
<= mtu
) {
719 nf_bridge_info_free(skb
);
720 return br_dev_queue_push_xmit(net
, sk
, skb
);
723 /* This is wrong! We should preserve the original fragment
724 * boundaries by preserving frag_list rather than refragmenting.
726 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4
) &&
727 skb
->protocol
== htons(ETH_P_IP
)) {
728 struct brnf_frag_data
*data
;
730 if (br_validate_ipv4(net
, skb
))
733 IPCB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
735 nf_bridge_update_protocol(skb
);
737 data
= this_cpu_ptr(&brnf_frag_data_storage
);
739 data
->vlan_tci
= skb
->vlan_tci
;
740 data
->vlan_proto
= skb
->vlan_proto
;
741 data
->encap_size
= nf_bridge_encap_header_len(skb
);
742 data
->size
= ETH_HLEN
+ data
->encap_size
;
744 skb_copy_from_linear_data_offset(skb
, -data
->size
, data
->mac
,
747 return br_nf_ip_fragment(net
, sk
, skb
, br_nf_push_frag_xmit
);
749 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6
) &&
750 skb
->protocol
== htons(ETH_P_IPV6
)) {
751 const struct nf_ipv6_ops
*v6ops
= nf_get_ipv6_ops();
752 struct brnf_frag_data
*data
;
754 if (br_validate_ipv6(net
, skb
))
757 IP6CB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
759 nf_bridge_update_protocol(skb
);
761 data
= this_cpu_ptr(&brnf_frag_data_storage
);
762 data
->encap_size
= nf_bridge_encap_header_len(skb
);
763 data
->size
= ETH_HLEN
+ data
->encap_size
;
765 skb_copy_from_linear_data_offset(skb
, -data
->size
, data
->mac
,
769 return v6ops
->fragment(net
, sk
, skb
, br_nf_push_frag_xmit
);
774 nf_bridge_info_free(skb
);
775 return br_dev_queue_push_xmit(net
, sk
, skb
);
781 /* PF_BRIDGE/POST_ROUTING ********************************************/
782 static unsigned int br_nf_post_routing(void *priv
,
784 const struct nf_hook_state
*state
)
786 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
787 struct net_device
*realoutdev
= bridge_parent(skb
->dev
);
790 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
791 * on a bridge, but was delivered locally and is now being routed:
793 * POST_ROUTING was already invoked from the ip stack.
795 if (!nf_bridge
|| !nf_bridge
->physoutdev
)
801 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
803 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
808 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
809 * about the value of skb->pkt_type. */
810 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
811 skb
->pkt_type
= PACKET_HOST
;
812 nf_bridge
->pkt_otherhost
= true;
815 nf_bridge_pull_encap_header(skb
);
816 if (pf
== NFPROTO_IPV4
)
817 skb
->protocol
= htons(ETH_P_IP
);
819 skb
->protocol
= htons(ETH_P_IPV6
);
821 NF_HOOK(pf
, NF_INET_POST_ROUTING
, state
->net
, state
->sk
, skb
,
823 br_nf_dev_queue_xmit
);
828 /* IP/SABOTAGE *****************************************************/
829 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
830 * for the second time. */
831 static unsigned int ip_sabotage_in(void *priv
,
833 const struct nf_hook_state
*state
)
835 if (skb
->nf_bridge
&& !skb
->nf_bridge
->in_prerouting
&&
836 !netif_is_l3_master(skb
->dev
)) {
837 state
->okfn(state
->net
, state
->sk
, skb
);
844 /* This is called when br_netfilter has called into iptables/netfilter,
845 * and DNAT has taken place on a bridge-forwarded packet.
847 * neigh->output has created a new MAC header, with local br0 MAC
850 * This restores the original MAC saddr of the bridged packet
851 * before invoking bridge forward logic to transmit the packet.
853 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff
*skb
)
855 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
857 skb_pull(skb
, ETH_HLEN
);
858 nf_bridge
->bridged_dnat
= 0;
860 BUILD_BUG_ON(sizeof(nf_bridge
->neigh_header
) != (ETH_HLEN
- ETH_ALEN
));
862 skb_copy_to_linear_data_offset(skb
, -(ETH_HLEN
- ETH_ALEN
),
863 nf_bridge
->neigh_header
,
864 ETH_HLEN
- ETH_ALEN
);
865 skb
->dev
= nf_bridge
->physindev
;
867 nf_bridge
->physoutdev
= NULL
;
868 br_handle_frame_finish(dev_net(skb
->dev
), NULL
, skb
);
871 static int br_nf_dev_xmit(struct sk_buff
*skb
)
873 if (skb
->nf_bridge
&& skb
->nf_bridge
->bridged_dnat
) {
874 br_nf_pre_routing_finish_bridge_slow(skb
);
880 static const struct nf_br_ops br_ops
= {
881 .br_dev_xmit_hook
= br_nf_dev_xmit
,
884 void br_netfilter_enable(void)
887 EXPORT_SYMBOL_GPL(br_netfilter_enable
);
889 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
890 * br_dev_queue_push_xmit is called afterwards */
891 static const struct nf_hook_ops br_nf_ops
[] = {
893 .hook
= br_nf_pre_routing
,
894 .pf
= NFPROTO_BRIDGE
,
895 .hooknum
= NF_BR_PRE_ROUTING
,
896 .priority
= NF_BR_PRI_BRNF
,
899 .hook
= br_nf_forward_ip
,
900 .pf
= NFPROTO_BRIDGE
,
901 .hooknum
= NF_BR_FORWARD
,
902 .priority
= NF_BR_PRI_BRNF
- 1,
905 .hook
= br_nf_forward_arp
,
906 .pf
= NFPROTO_BRIDGE
,
907 .hooknum
= NF_BR_FORWARD
,
908 .priority
= NF_BR_PRI_BRNF
,
911 .hook
= br_nf_post_routing
,
912 .pf
= NFPROTO_BRIDGE
,
913 .hooknum
= NF_BR_POST_ROUTING
,
914 .priority
= NF_BR_PRI_LAST
,
917 .hook
= ip_sabotage_in
,
919 .hooknum
= NF_INET_PRE_ROUTING
,
920 .priority
= NF_IP_PRI_FIRST
,
923 .hook
= ip_sabotage_in
,
925 .hooknum
= NF_INET_PRE_ROUTING
,
926 .priority
= NF_IP6_PRI_FIRST
,
930 static int brnf_device_event(struct notifier_block
*unused
, unsigned long event
,
933 struct net_device
*dev
= netdev_notifier_info_to_dev(ptr
);
934 struct brnf_net
*brnet
;
938 if (event
!= NETDEV_REGISTER
|| !(dev
->priv_flags
& IFF_EBRIDGE
))
944 brnet
= net_generic(net
, brnf_net_id
);
948 ret
= nf_register_net_hooks(net
, br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
952 brnet
->enabled
= true;
956 static void __net_exit
brnf_exit_net(struct net
*net
)
958 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
963 nf_unregister_net_hooks(net
, br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
964 brnet
->enabled
= false;
967 static struct pernet_operations brnf_net_ops __read_mostly
= {
968 .exit
= brnf_exit_net
,
970 .size
= sizeof(struct brnf_net
),
973 static struct notifier_block brnf_notifier __read_mostly
= {
974 .notifier_call
= brnf_device_event
,
977 /* recursively invokes nf_hook_slow (again), skipping already-called
978 * hooks (< NF_BR_PRI_BRNF).
980 * Called with rcu read lock held.
982 int br_nf_hook_thresh(unsigned int hook
, struct net
*net
,
983 struct sock
*sk
, struct sk_buff
*skb
,
984 struct net_device
*indev
,
985 struct net_device
*outdev
,
986 int (*okfn
)(struct net
*, struct sock
*,
989 const struct nf_hook_entries
*e
;
990 struct nf_hook_state state
;
991 struct nf_hook_ops
**ops
;
995 e
= rcu_dereference(net
->nf
.hooks
[NFPROTO_BRIDGE
][hook
]);
997 return okfn(net
, sk
, skb
);
999 ops
= nf_hook_entries_get_hook_ops(e
);
1000 for (i
= 0; i
< e
->num_hook_entries
&&
1001 ops
[i
]->priority
<= NF_BR_PRI_BRNF
; i
++)
1004 nf_hook_state_init(&state
, hook
, NFPROTO_BRIDGE
, indev
, outdev
,
1007 ret
= nf_hook_slow(skb
, &state
, e
, i
);
1009 ret
= okfn(net
, sk
, skb
);
1014 #ifdef CONFIG_SYSCTL
1016 int brnf_sysctl_call_tables(struct ctl_table
*ctl
, int write
,
1017 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1021 ret
= proc_dointvec(ctl
, write
, buffer
, lenp
, ppos
);
1023 if (write
&& *(int *)(ctl
->data
))
1024 *(int *)(ctl
->data
) = 1;
1028 static struct ctl_table brnf_table
[] = {
1030 .procname
= "bridge-nf-call-arptables",
1031 .data
= &brnf_call_arptables
,
1032 .maxlen
= sizeof(int),
1034 .proc_handler
= brnf_sysctl_call_tables
,
1037 .procname
= "bridge-nf-call-iptables",
1038 .data
= &brnf_call_iptables
,
1039 .maxlen
= sizeof(int),
1041 .proc_handler
= brnf_sysctl_call_tables
,
1044 .procname
= "bridge-nf-call-ip6tables",
1045 .data
= &brnf_call_ip6tables
,
1046 .maxlen
= sizeof(int),
1048 .proc_handler
= brnf_sysctl_call_tables
,
1051 .procname
= "bridge-nf-filter-vlan-tagged",
1052 .data
= &brnf_filter_vlan_tagged
,
1053 .maxlen
= sizeof(int),
1055 .proc_handler
= brnf_sysctl_call_tables
,
1058 .procname
= "bridge-nf-filter-pppoe-tagged",
1059 .data
= &brnf_filter_pppoe_tagged
,
1060 .maxlen
= sizeof(int),
1062 .proc_handler
= brnf_sysctl_call_tables
,
1065 .procname
= "bridge-nf-pass-vlan-input-dev",
1066 .data
= &brnf_pass_vlan_indev
,
1067 .maxlen
= sizeof(int),
1069 .proc_handler
= brnf_sysctl_call_tables
,
1075 static int __init
br_netfilter_init(void)
1079 ret
= register_pernet_subsys(&brnf_net_ops
);
1083 ret
= register_netdevice_notifier(&brnf_notifier
);
1085 unregister_pernet_subsys(&brnf_net_ops
);
1089 #ifdef CONFIG_SYSCTL
1090 brnf_sysctl_header
= register_net_sysctl(&init_net
, "net/bridge", brnf_table
);
1091 if (brnf_sysctl_header
== NULL
) {
1093 "br_netfilter: can't register to sysctl.\n");
1094 unregister_netdevice_notifier(&brnf_notifier
);
1095 unregister_pernet_subsys(&brnf_net_ops
);
1099 RCU_INIT_POINTER(nf_br_ops
, &br_ops
);
1100 printk(KERN_NOTICE
"Bridge firewalling registered\n");
1104 static void __exit
br_netfilter_fini(void)
1106 RCU_INIT_POINTER(nf_br_ops
, NULL
);
1107 unregister_netdevice_notifier(&brnf_notifier
);
1108 unregister_pernet_subsys(&brnf_net_ops
);
1109 #ifdef CONFIG_SYSCTL
1110 unregister_net_sysctl_table(brnf_sysctl_header
);
1114 module_init(br_netfilter_init
);
1115 module_exit(br_netfilter_fini
);
1117 MODULE_LICENSE("GPL");
1118 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1119 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1120 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");