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/inetdevice.h>
37 #include <net/route.h>
38 #include <net/netfilter/br_netfilter.h>
40 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
41 #include <net/netfilter/nf_conntrack.h>
44 #include <asm/uaccess.h>
45 #include "br_private.h"
47 #include <linux/sysctl.h>
51 static struct ctl_table_header
*brnf_sysctl_header
;
52 static int brnf_call_iptables __read_mostly
= 1;
53 static int brnf_call_ip6tables __read_mostly
= 1;
54 static int brnf_call_arptables __read_mostly
= 1;
55 static int brnf_filter_vlan_tagged __read_mostly
= 0;
56 static int brnf_filter_pppoe_tagged __read_mostly
= 0;
57 static int brnf_pass_vlan_indev __read_mostly
= 0;
59 #define brnf_call_iptables 1
60 #define brnf_call_ip6tables 1
61 #define brnf_call_arptables 1
62 #define brnf_filter_vlan_tagged 0
63 #define brnf_filter_pppoe_tagged 0
64 #define brnf_pass_vlan_indev 0
68 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
70 #define IS_IPV6(skb) \
71 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
74 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
76 static inline __be16
vlan_proto(const struct sk_buff
*skb
)
78 if (skb_vlan_tag_present(skb
))
80 else if (skb
->protocol
== htons(ETH_P_8021Q
))
81 return vlan_eth_hdr(skb
)->h_vlan_encapsulated_proto
;
86 #define IS_VLAN_IP(skb) \
87 (vlan_proto(skb) == htons(ETH_P_IP) && \
88 brnf_filter_vlan_tagged)
90 #define IS_VLAN_IPV6(skb) \
91 (vlan_proto(skb) == htons(ETH_P_IPV6) && \
92 brnf_filter_vlan_tagged)
94 #define IS_VLAN_ARP(skb) \
95 (vlan_proto(skb) == htons(ETH_P_ARP) && \
96 brnf_filter_vlan_tagged)
98 static inline __be16
pppoe_proto(const struct sk_buff
*skb
)
100 return *((__be16
*)(skb_mac_header(skb
) + ETH_HLEN
+
101 sizeof(struct pppoe_hdr
)));
104 #define IS_PPPOE_IP(skb) \
105 (skb->protocol == htons(ETH_P_PPP_SES) && \
106 pppoe_proto(skb) == htons(PPP_IP) && \
107 brnf_filter_pppoe_tagged)
109 #define IS_PPPOE_IPV6(skb) \
110 (skb->protocol == htons(ETH_P_PPP_SES) && \
111 pppoe_proto(skb) == htons(PPP_IPV6) && \
112 brnf_filter_pppoe_tagged)
114 static inline struct rtable
*bridge_parent_rtable(const struct net_device
*dev
)
116 struct net_bridge_port
*port
;
118 port
= br_port_get_rcu(dev
);
119 return port
? &port
->br
->fake_rtable
: NULL
;
122 static inline struct net_device
*bridge_parent(const struct net_device
*dev
)
124 struct net_bridge_port
*port
;
126 port
= br_port_get_rcu(dev
);
127 return port
? port
->br
->dev
: NULL
;
130 static inline struct nf_bridge_info
*nf_bridge_alloc(struct sk_buff
*skb
)
132 skb
->nf_bridge
= kzalloc(sizeof(struct nf_bridge_info
), GFP_ATOMIC
);
133 if (likely(skb
->nf_bridge
))
134 atomic_set(&(skb
->nf_bridge
->use
), 1);
136 return skb
->nf_bridge
;
139 static inline struct nf_bridge_info
*nf_bridge_unshare(struct sk_buff
*skb
)
141 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
143 if (atomic_read(&nf_bridge
->use
) > 1) {
144 struct nf_bridge_info
*tmp
= nf_bridge_alloc(skb
);
147 memcpy(tmp
, nf_bridge
, sizeof(struct nf_bridge_info
));
148 atomic_set(&tmp
->use
, 1);
150 nf_bridge_put(nf_bridge
);
156 static unsigned int nf_bridge_encap_header_len(const struct sk_buff
*skb
)
158 switch (skb
->protocol
) {
159 case __cpu_to_be16(ETH_P_8021Q
):
161 case __cpu_to_be16(ETH_P_PPP_SES
):
162 return PPPOE_SES_HLEN
;
168 static inline void nf_bridge_push_encap_header(struct sk_buff
*skb
)
170 unsigned int len
= nf_bridge_encap_header_len(skb
);
173 skb
->network_header
-= len
;
176 static inline void nf_bridge_pull_encap_header(struct sk_buff
*skb
)
178 unsigned int len
= nf_bridge_encap_header_len(skb
);
181 skb
->network_header
+= len
;
184 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff
*skb
)
186 unsigned int len
= nf_bridge_encap_header_len(skb
);
188 skb_pull_rcsum(skb
, len
);
189 skb
->network_header
+= len
;
192 static inline void nf_bridge_save_header(struct sk_buff
*skb
)
194 int header_size
= ETH_HLEN
+ nf_bridge_encap_header_len(skb
);
196 skb_copy_from_linear_data_offset(skb
, -header_size
,
197 skb
->nf_bridge
->data
, header_size
);
200 /* When handing a packet over to the IP layer
201 * check whether we have a skb that is in the
205 static int br_parse_ip_options(struct sk_buff
*skb
)
207 const struct iphdr
*iph
;
208 struct net_device
*dev
= skb
->dev
;
211 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
216 /* Basic sanity checks */
217 if (iph
->ihl
< 5 || iph
->version
!= 4)
220 if (!pskb_may_pull(skb
, iph
->ihl
*4))
224 if (unlikely(ip_fast_csum((u8
*)iph
, iph
->ihl
)))
227 len
= ntohs(iph
->tot_len
);
228 if (skb
->len
< len
) {
229 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INTRUNCATEDPKTS
);
231 } else if (len
< (iph
->ihl
*4))
234 if (pskb_trim_rcsum(skb
, len
)) {
235 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INDISCARDS
);
239 memset(IPCB(skb
), 0, sizeof(struct inet_skb_parm
));
240 /* We should really parse IP options here but until
241 * somebody who actually uses IP options complains to
242 * us we'll just silently ignore the options because
248 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INHDRERRORS
);
253 static void nf_bridge_update_protocol(struct sk_buff
*skb
)
255 if (skb
->nf_bridge
->mask
& BRNF_8021Q
)
256 skb
->protocol
= htons(ETH_P_8021Q
);
257 else if (skb
->nf_bridge
->mask
& BRNF_PPPoE
)
258 skb
->protocol
= htons(ETH_P_PPP_SES
);
261 /* PF_BRIDGE/PRE_ROUTING *********************************************/
262 /* Undo the changes made for ip6tables PREROUTING and continue the
263 * bridge PRE_ROUTING hook. */
264 static int br_nf_pre_routing_finish_ipv6(struct sk_buff
*skb
)
266 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
269 if (nf_bridge
->mask
& BRNF_PKT_TYPE
) {
270 skb
->pkt_type
= PACKET_OTHERHOST
;
271 nf_bridge
->mask
^= BRNF_PKT_TYPE
;
273 nf_bridge
->mask
^= BRNF_NF_BRIDGE_PREROUTING
;
275 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
280 skb_dst_set_noref(skb
, &rt
->dst
);
282 skb
->dev
= nf_bridge
->physindev
;
283 nf_bridge_update_protocol(skb
);
284 nf_bridge_push_encap_header(skb
);
285 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_PRE_ROUTING
, skb
, skb
->dev
, NULL
,
286 br_handle_frame_finish
, 1);
291 /* Obtain the correct destination MAC address, while preserving the original
292 * source MAC address. If we already know this address, we just copy it. If we
293 * don't, we use the neighbour framework to find out. In both cases, we make
294 * sure that br_handle_frame_finish() is called afterwards.
296 static int br_nf_pre_routing_finish_bridge(struct sk_buff
*skb
)
298 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
299 struct neighbour
*neigh
;
300 struct dst_entry
*dst
;
302 skb
->dev
= bridge_parent(skb
->dev
);
306 neigh
= dst_neigh_lookup_skb(dst
, skb
);
310 if (neigh
->hh
.hh_len
) {
311 neigh_hh_bridge(&neigh
->hh
, skb
);
312 skb
->dev
= nf_bridge
->physindev
;
313 ret
= br_handle_frame_finish(skb
);
315 /* the neighbour function below overwrites the complete
316 * MAC header, so we save the Ethernet source address and
319 skb_copy_from_linear_data_offset(skb
,
320 -(ETH_HLEN
-ETH_ALEN
),
321 skb
->nf_bridge
->data
,
323 /* tell br_dev_xmit to continue with forwarding */
324 nf_bridge
->mask
|= BRNF_BRIDGED_DNAT
;
325 /* FIXME Need to refragment */
326 ret
= neigh
->output(neigh
, skb
);
328 neigh_release(neigh
);
336 static bool dnat_took_place(const struct sk_buff
*skb
)
338 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
339 enum ip_conntrack_info ctinfo
;
342 ct
= nf_ct_get(skb
, &ctinfo
);
343 if (!ct
|| nf_ct_is_untracked(ct
))
346 return test_bit(IPS_DST_NAT_BIT
, &ct
->status
);
352 /* This requires some explaining. If DNAT has taken place,
353 * we will need to fix up the destination Ethernet address.
355 * There are two cases to consider:
356 * 1. The packet was DNAT'ed to a device in the same bridge
357 * port group as it was received on. We can still bridge
359 * 2. The packet was DNAT'ed to a different device, either
360 * a non-bridged device or another bridge port group.
361 * The packet will need to be routed.
363 * The correct way of distinguishing between these two cases is to
364 * call ip_route_input() and to look at skb->dst->dev, which is
365 * changed to the destination device if ip_route_input() succeeds.
367 * Let's first consider the case that ip_route_input() succeeds:
369 * If the output device equals the logical bridge device the packet
370 * came in on, we can consider this bridging. The corresponding MAC
371 * address will be obtained in br_nf_pre_routing_finish_bridge.
372 * Otherwise, the packet is considered to be routed and we just
373 * change the destination MAC address so that the packet will
374 * later be passed up to the IP stack to be routed. For a redirected
375 * packet, ip_route_input() will give back the localhost as output device,
376 * which differs from the bridge device.
378 * Let's now consider the case that ip_route_input() fails:
380 * This can be because the destination address is martian, in which case
381 * the packet will be dropped.
382 * If IP forwarding is disabled, ip_route_input() will fail, while
383 * ip_route_output_key() can return success. The source
384 * address for ip_route_output_key() is set to zero, so ip_route_output_key()
385 * thinks we're handling a locally generated packet and won't care
386 * if IP forwarding is enabled. If the output device equals the logical bridge
387 * device, we proceed as if ip_route_input() succeeded. If it differs from the
388 * logical bridge port or if ip_route_output_key() fails we drop the packet.
390 static int br_nf_pre_routing_finish(struct sk_buff
*skb
)
392 struct net_device
*dev
= skb
->dev
;
393 struct iphdr
*iph
= ip_hdr(skb
);
394 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
399 frag_max_size
= IPCB(skb
)->frag_max_size
;
400 BR_INPUT_SKB_CB(skb
)->frag_max_size
= frag_max_size
;
402 if (nf_bridge
->mask
& BRNF_PKT_TYPE
) {
403 skb
->pkt_type
= PACKET_OTHERHOST
;
404 nf_bridge
->mask
^= BRNF_PKT_TYPE
;
406 nf_bridge
->mask
^= BRNF_NF_BRIDGE_PREROUTING
;
407 if (dnat_took_place(skb
)) {
408 if ((err
= ip_route_input(skb
, iph
->daddr
, iph
->saddr
, iph
->tos
, dev
))) {
409 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
411 /* If err equals -EHOSTUNREACH the error is due to a
412 * martian destination or due to the fact that
413 * forwarding is disabled. For most martian packets,
414 * ip_route_output_key() will fail. It won't fail for 2 types of
415 * martian destinations: loopback destinations and destination
416 * 0.0.0.0. In both cases the packet will be dropped because the
417 * destination is the loopback device and not the bridge. */
418 if (err
!= -EHOSTUNREACH
|| !in_dev
|| IN_DEV_FORWARD(in_dev
))
421 rt
= ip_route_output(dev_net(dev
), iph
->daddr
, 0,
422 RT_TOS(iph
->tos
), 0);
424 /* - Bridged-and-DNAT'ed traffic doesn't
425 * require ip_forwarding. */
426 if (rt
->dst
.dev
== dev
) {
427 skb_dst_set(skb
, &rt
->dst
);
436 if (skb_dst(skb
)->dev
== dev
) {
438 skb
->dev
= nf_bridge
->physindev
;
439 nf_bridge_update_protocol(skb
);
440 nf_bridge_push_encap_header(skb
);
441 NF_HOOK_THRESH(NFPROTO_BRIDGE
,
444 br_nf_pre_routing_finish_bridge
,
448 ether_addr_copy(eth_hdr(skb
)->h_dest
, dev
->dev_addr
);
449 skb
->pkt_type
= PACKET_HOST
;
452 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
457 skb_dst_set_noref(skb
, &rt
->dst
);
460 skb
->dev
= nf_bridge
->physindev
;
461 nf_bridge_update_protocol(skb
);
462 nf_bridge_push_encap_header(skb
);
463 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_PRE_ROUTING
, skb
, skb
->dev
, NULL
,
464 br_handle_frame_finish
, 1);
469 static struct net_device
*brnf_get_logical_dev(struct sk_buff
*skb
, const struct net_device
*dev
)
471 struct net_device
*vlan
, *br
;
473 br
= bridge_parent(dev
);
474 if (brnf_pass_vlan_indev
== 0 || !skb_vlan_tag_present(skb
))
477 vlan
= __vlan_find_dev_deep_rcu(br
, skb
->vlan_proto
,
478 skb_vlan_tag_get(skb
) & VLAN_VID_MASK
);
480 return vlan
? vlan
: br
;
483 /* Some common code for IPv4/IPv6 */
484 static struct net_device
*setup_pre_routing(struct sk_buff
*skb
)
486 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
488 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
489 skb
->pkt_type
= PACKET_HOST
;
490 nf_bridge
->mask
|= BRNF_PKT_TYPE
;
493 nf_bridge
->mask
|= BRNF_NF_BRIDGE_PREROUTING
;
494 nf_bridge
->physindev
= skb
->dev
;
495 skb
->dev
= brnf_get_logical_dev(skb
, skb
->dev
);
496 if (skb
->protocol
== htons(ETH_P_8021Q
))
497 nf_bridge
->mask
|= BRNF_8021Q
;
498 else if (skb
->protocol
== htons(ETH_P_PPP_SES
))
499 nf_bridge
->mask
|= BRNF_PPPoE
;
501 /* Must drop socket now because of tproxy. */
506 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
507 static int check_hbh_len(struct sk_buff
*skb
)
509 unsigned char *raw
= (u8
*)(ipv6_hdr(skb
) + 1);
511 const unsigned char *nh
= skb_network_header(skb
);
513 int len
= (raw
[1] + 1) << 3;
515 if ((raw
+ len
) - skb
->data
> skb_headlen(skb
))
522 int optlen
= nh
[off
+ 1] + 2;
533 if (nh
[off
+ 1] != 4 || (off
& 3) != 2)
535 pkt_len
= ntohl(*(__be32
*) (nh
+ off
+ 2));
536 if (pkt_len
<= IPV6_MAXPLEN
||
537 ipv6_hdr(skb
)->payload_len
)
539 if (pkt_len
> skb
->len
- sizeof(struct ipv6hdr
))
541 if (pskb_trim_rcsum(skb
,
542 pkt_len
+ sizeof(struct ipv6hdr
)))
544 nh
= skb_network_header(skb
);
561 /* Replicate the checks that IPv6 does on packet reception and pass the packet
562 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
563 static unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops
*ops
,
565 const struct nf_hook_state
*state
)
567 const struct ipv6hdr
*hdr
;
570 if (skb
->len
< sizeof(struct ipv6hdr
))
573 if (!pskb_may_pull(skb
, sizeof(struct ipv6hdr
)))
578 if (hdr
->version
!= 6)
581 pkt_len
= ntohs(hdr
->payload_len
);
583 if (pkt_len
|| hdr
->nexthdr
!= NEXTHDR_HOP
) {
584 if (pkt_len
+ sizeof(struct ipv6hdr
) > skb
->len
)
586 if (pskb_trim_rcsum(skb
, pkt_len
+ sizeof(struct ipv6hdr
)))
589 if (hdr
->nexthdr
== NEXTHDR_HOP
&& check_hbh_len(skb
))
592 nf_bridge_put(skb
->nf_bridge
);
593 if (!nf_bridge_alloc(skb
))
595 if (!setup_pre_routing(skb
))
598 skb
->protocol
= htons(ETH_P_IPV6
);
599 NF_HOOK(NFPROTO_IPV6
, NF_INET_PRE_ROUTING
, skb
, skb
->dev
, NULL
,
600 br_nf_pre_routing_finish_ipv6
);
605 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
606 * Replicate the checks that IPv4 does on packet reception.
607 * Set skb->dev to the bridge device (i.e. parent of the
608 * receiving device) to make netfilter happy, the REDIRECT
609 * target in particular. Save the original destination IP
610 * address to be able to detect DNAT afterwards. */
611 static unsigned int br_nf_pre_routing(const struct nf_hook_ops
*ops
,
613 const struct nf_hook_state
*state
)
615 struct net_bridge_port
*p
;
616 struct net_bridge
*br
;
617 __u32 len
= nf_bridge_encap_header_len(skb
);
619 if (unlikely(!pskb_may_pull(skb
, len
)))
622 p
= br_port_get_rcu(state
->in
);
627 if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
)) {
628 if (!brnf_call_ip6tables
&& !br
->nf_call_ip6tables
)
631 nf_bridge_pull_encap_header_rcsum(skb
);
632 return br_nf_pre_routing_ipv6(ops
, skb
, state
);
635 if (!brnf_call_iptables
&& !br
->nf_call_iptables
)
638 if (!IS_IP(skb
) && !IS_VLAN_IP(skb
) && !IS_PPPOE_IP(skb
))
641 nf_bridge_pull_encap_header_rcsum(skb
);
643 if (br_parse_ip_options(skb
))
646 nf_bridge_put(skb
->nf_bridge
);
647 if (!nf_bridge_alloc(skb
))
649 if (!setup_pre_routing(skb
))
652 skb
->protocol
= htons(ETH_P_IP
);
654 NF_HOOK(NFPROTO_IPV4
, NF_INET_PRE_ROUTING
, skb
, skb
->dev
, NULL
,
655 br_nf_pre_routing_finish
);
661 /* PF_BRIDGE/LOCAL_IN ************************************************/
662 /* The packet is locally destined, which requires a real
663 * dst_entry, so detach the fake one. On the way up, the
664 * packet would pass through PRE_ROUTING again (which already
665 * took place when the packet entered the bridge), but we
666 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
667 * prevent this from happening. */
668 static unsigned int br_nf_local_in(const struct nf_hook_ops
*ops
,
670 const struct nf_hook_state
*state
)
672 br_drop_fake_rtable(skb
);
676 /* PF_BRIDGE/FORWARD *************************************************/
677 static int br_nf_forward_finish(struct sk_buff
*skb
)
679 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
680 struct net_device
*in
;
682 if (!IS_ARP(skb
) && !IS_VLAN_ARP(skb
)) {
683 in
= nf_bridge
->physindev
;
684 if (nf_bridge
->mask
& BRNF_PKT_TYPE
) {
685 skb
->pkt_type
= PACKET_OTHERHOST
;
686 nf_bridge
->mask
^= BRNF_PKT_TYPE
;
688 nf_bridge_update_protocol(skb
);
690 in
= *((struct net_device
**)(skb
->cb
));
692 nf_bridge_push_encap_header(skb
);
694 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_FORWARD
, skb
, in
,
695 skb
->dev
, br_forward_finish
, 1);
700 /* This is the 'purely bridged' case. For IP, we pass the packet to
701 * netfilter with indev and outdev set to the bridge device,
702 * but we are still able to filter on the 'real' indev/outdev
703 * because of the physdev module. For ARP, indev and outdev are the
705 static unsigned int br_nf_forward_ip(const struct nf_hook_ops
*ops
,
707 const struct nf_hook_state
*state
)
709 struct nf_bridge_info
*nf_bridge
;
710 struct net_device
*parent
;
716 /* Need exclusive nf_bridge_info since we might have multiple
717 * different physoutdevs. */
718 if (!nf_bridge_unshare(skb
))
721 parent
= bridge_parent(state
->out
);
725 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
727 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
732 nf_bridge_pull_encap_header(skb
);
734 nf_bridge
= skb
->nf_bridge
;
735 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
736 skb
->pkt_type
= PACKET_HOST
;
737 nf_bridge
->mask
|= BRNF_PKT_TYPE
;
740 if (pf
== NFPROTO_IPV4
&& br_parse_ip_options(skb
))
743 nf_bridge
->physoutdev
= skb
->dev
;
744 if (pf
== NFPROTO_IPV4
)
745 skb
->protocol
= htons(ETH_P_IP
);
747 skb
->protocol
= htons(ETH_P_IPV6
);
749 NF_HOOK(pf
, NF_INET_FORWARD
, skb
, brnf_get_logical_dev(skb
, state
->in
),
750 parent
, br_nf_forward_finish
);
755 static unsigned int br_nf_forward_arp(const struct nf_hook_ops
*ops
,
757 const struct nf_hook_state
*state
)
759 struct net_bridge_port
*p
;
760 struct net_bridge
*br
;
761 struct net_device
**d
= (struct net_device
**)(skb
->cb
);
763 p
= br_port_get_rcu(state
->out
);
768 if (!brnf_call_arptables
&& !br
->nf_call_arptables
)
772 if (!IS_VLAN_ARP(skb
))
774 nf_bridge_pull_encap_header(skb
);
777 if (arp_hdr(skb
)->ar_pln
!= 4) {
778 if (IS_VLAN_ARP(skb
))
779 nf_bridge_push_encap_header(skb
);
783 NF_HOOK(NFPROTO_ARP
, NF_ARP_FORWARD
, skb
, state
->in
,
784 state
->out
, br_nf_forward_finish
);
789 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
790 static bool nf_bridge_copy_header(struct sk_buff
*skb
)
793 unsigned int header_size
;
795 nf_bridge_update_protocol(skb
);
796 header_size
= ETH_HLEN
+ nf_bridge_encap_header_len(skb
);
797 err
= skb_cow_head(skb
, header_size
);
801 skb_copy_to_linear_data_offset(skb
, -header_size
,
802 skb
->nf_bridge
->data
, header_size
);
803 __skb_push(skb
, nf_bridge_encap_header_len(skb
));
807 static int br_nf_push_frag_xmit(struct sk_buff
*skb
)
809 if (!nf_bridge_copy_header(skb
)) {
814 return br_dev_queue_push_xmit(skb
);
817 static int br_nf_dev_queue_xmit(struct sk_buff
*skb
)
821 unsigned int mtu_reserved
;
823 if (skb_is_gso(skb
) || skb
->protocol
!= htons(ETH_P_IP
))
824 return br_dev_queue_push_xmit(skb
);
826 mtu_reserved
= nf_bridge_mtu_reduction(skb
);
827 /* This is wrong! We should preserve the original fragment
828 * boundaries by preserving frag_list rather than refragmenting.
830 if (skb
->len
+ mtu_reserved
> skb
->dev
->mtu
) {
831 frag_max_size
= BR_INPUT_SKB_CB(skb
)->frag_max_size
;
832 if (br_parse_ip_options(skb
))
833 /* Drop invalid packet */
835 IPCB(skb
)->frag_max_size
= frag_max_size
;
836 ret
= ip_fragment(skb
, br_nf_push_frag_xmit
);
838 ret
= br_dev_queue_push_xmit(skb
);
843 static int br_nf_dev_queue_xmit(struct sk_buff
*skb
)
845 return br_dev_queue_push_xmit(skb
);
849 /* PF_BRIDGE/POST_ROUTING ********************************************/
850 static unsigned int br_nf_post_routing(const struct nf_hook_ops
*ops
,
852 const struct nf_hook_state
*state
)
854 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
855 struct net_device
*realoutdev
= bridge_parent(skb
->dev
);
858 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
859 * on a bridge, but was delivered locally and is now being routed:
861 * POST_ROUTING was already invoked from the ip stack.
863 if (!nf_bridge
|| !nf_bridge
->physoutdev
)
869 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
871 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
876 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
877 * about the value of skb->pkt_type. */
878 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
879 skb
->pkt_type
= PACKET_HOST
;
880 nf_bridge
->mask
|= BRNF_PKT_TYPE
;
883 nf_bridge_pull_encap_header(skb
);
884 nf_bridge_save_header(skb
);
885 if (pf
== NFPROTO_IPV4
)
886 skb
->protocol
= htons(ETH_P_IP
);
888 skb
->protocol
= htons(ETH_P_IPV6
);
890 NF_HOOK(pf
, NF_INET_POST_ROUTING
, skb
, NULL
, realoutdev
,
891 br_nf_dev_queue_xmit
);
896 /* IP/SABOTAGE *****************************************************/
897 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
898 * for the second time. */
899 static unsigned int ip_sabotage_in(const struct nf_hook_ops
*ops
,
901 const struct nf_hook_state
*state
)
903 if (skb
->nf_bridge
&&
904 !(skb
->nf_bridge
->mask
& BRNF_NF_BRIDGE_PREROUTING
)) {
911 /* This is called when br_netfilter has called into iptables/netfilter,
912 * and DNAT has taken place on a bridge-forwarded packet.
914 * neigh->output has created a new MAC header, with local br0 MAC
917 * This restores the original MAC saddr of the bridged packet
918 * before invoking bridge forward logic to transmit the packet.
920 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff
*skb
)
922 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
924 skb_pull(skb
, ETH_HLEN
);
925 nf_bridge
->mask
&= ~BRNF_BRIDGED_DNAT
;
927 skb_copy_to_linear_data_offset(skb
, -(ETH_HLEN
-ETH_ALEN
),
928 skb
->nf_bridge
->data
, ETH_HLEN
-ETH_ALEN
);
929 skb
->dev
= nf_bridge
->physindev
;
930 br_handle_frame_finish(skb
);
933 static int br_nf_dev_xmit(struct sk_buff
*skb
)
935 if (skb
->nf_bridge
&& (skb
->nf_bridge
->mask
& BRNF_BRIDGED_DNAT
)) {
936 br_nf_pre_routing_finish_bridge_slow(skb
);
942 static const struct nf_br_ops br_ops
= {
943 .br_dev_xmit_hook
= br_nf_dev_xmit
,
946 void br_netfilter_enable(void)
949 EXPORT_SYMBOL_GPL(br_netfilter_enable
);
951 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
952 * br_dev_queue_push_xmit is called afterwards */
953 static struct nf_hook_ops br_nf_ops
[] __read_mostly
= {
955 .hook
= br_nf_pre_routing
,
956 .owner
= THIS_MODULE
,
957 .pf
= NFPROTO_BRIDGE
,
958 .hooknum
= NF_BR_PRE_ROUTING
,
959 .priority
= NF_BR_PRI_BRNF
,
962 .hook
= br_nf_local_in
,
963 .owner
= THIS_MODULE
,
964 .pf
= NFPROTO_BRIDGE
,
965 .hooknum
= NF_BR_LOCAL_IN
,
966 .priority
= NF_BR_PRI_BRNF
,
969 .hook
= br_nf_forward_ip
,
970 .owner
= THIS_MODULE
,
971 .pf
= NFPROTO_BRIDGE
,
972 .hooknum
= NF_BR_FORWARD
,
973 .priority
= NF_BR_PRI_BRNF
- 1,
976 .hook
= br_nf_forward_arp
,
977 .owner
= THIS_MODULE
,
978 .pf
= NFPROTO_BRIDGE
,
979 .hooknum
= NF_BR_FORWARD
,
980 .priority
= NF_BR_PRI_BRNF
,
983 .hook
= br_nf_post_routing
,
984 .owner
= THIS_MODULE
,
985 .pf
= NFPROTO_BRIDGE
,
986 .hooknum
= NF_BR_POST_ROUTING
,
987 .priority
= NF_BR_PRI_LAST
,
990 .hook
= ip_sabotage_in
,
991 .owner
= THIS_MODULE
,
993 .hooknum
= NF_INET_PRE_ROUTING
,
994 .priority
= NF_IP_PRI_FIRST
,
997 .hook
= ip_sabotage_in
,
998 .owner
= THIS_MODULE
,
1000 .hooknum
= NF_INET_PRE_ROUTING
,
1001 .priority
= NF_IP6_PRI_FIRST
,
1005 #ifdef CONFIG_SYSCTL
1007 int brnf_sysctl_call_tables(struct ctl_table
*ctl
, int write
,
1008 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1012 ret
= proc_dointvec(ctl
, write
, buffer
, lenp
, ppos
);
1014 if (write
&& *(int *)(ctl
->data
))
1015 *(int *)(ctl
->data
) = 1;
1019 static struct ctl_table brnf_table
[] = {
1021 .procname
= "bridge-nf-call-arptables",
1022 .data
= &brnf_call_arptables
,
1023 .maxlen
= sizeof(int),
1025 .proc_handler
= brnf_sysctl_call_tables
,
1028 .procname
= "bridge-nf-call-iptables",
1029 .data
= &brnf_call_iptables
,
1030 .maxlen
= sizeof(int),
1032 .proc_handler
= brnf_sysctl_call_tables
,
1035 .procname
= "bridge-nf-call-ip6tables",
1036 .data
= &brnf_call_ip6tables
,
1037 .maxlen
= sizeof(int),
1039 .proc_handler
= brnf_sysctl_call_tables
,
1042 .procname
= "bridge-nf-filter-vlan-tagged",
1043 .data
= &brnf_filter_vlan_tagged
,
1044 .maxlen
= sizeof(int),
1046 .proc_handler
= brnf_sysctl_call_tables
,
1049 .procname
= "bridge-nf-filter-pppoe-tagged",
1050 .data
= &brnf_filter_pppoe_tagged
,
1051 .maxlen
= sizeof(int),
1053 .proc_handler
= brnf_sysctl_call_tables
,
1056 .procname
= "bridge-nf-pass-vlan-input-dev",
1057 .data
= &brnf_pass_vlan_indev
,
1058 .maxlen
= sizeof(int),
1060 .proc_handler
= brnf_sysctl_call_tables
,
1066 static int __init
br_netfilter_init(void)
1070 ret
= nf_register_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1074 #ifdef CONFIG_SYSCTL
1075 brnf_sysctl_header
= register_net_sysctl(&init_net
, "net/bridge", brnf_table
);
1076 if (brnf_sysctl_header
== NULL
) {
1078 "br_netfilter: can't register to sysctl.\n");
1079 nf_unregister_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1083 RCU_INIT_POINTER(nf_br_ops
, &br_ops
);
1084 printk(KERN_NOTICE
"Bridge firewalling registered\n");
1088 static void __exit
br_netfilter_fini(void)
1090 RCU_INIT_POINTER(nf_br_ops
, NULL
);
1091 nf_unregister_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1092 #ifdef CONFIG_SYSCTL
1093 unregister_net_sysctl_table(brnf_sysctl_header
);
1097 module_init(br_netfilter_init
);
1098 module_exit(br_netfilter_fini
);
1100 MODULE_LICENSE("GPL");
1101 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1102 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1103 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");