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 #include <asm/uaccess.h>
41 #include "br_private.h"
43 #include <linux/sysctl.h>
47 static struct ctl_table_header
*brnf_sysctl_header
;
48 static int brnf_call_iptables __read_mostly
= 1;
49 static int brnf_call_ip6tables __read_mostly
= 1;
50 static int brnf_call_arptables __read_mostly
= 1;
51 static int brnf_filter_vlan_tagged __read_mostly
= 0;
52 static int brnf_filter_pppoe_tagged __read_mostly
= 0;
53 static int brnf_pass_vlan_indev __read_mostly
= 0;
55 #define brnf_call_iptables 1
56 #define brnf_call_ip6tables 1
57 #define brnf_call_arptables 1
58 #define brnf_filter_vlan_tagged 0
59 #define brnf_filter_pppoe_tagged 0
60 #define brnf_pass_vlan_indev 0
64 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
66 #define IS_IPV6(skb) \
67 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
70 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
72 static inline __be16
vlan_proto(const struct sk_buff
*skb
)
74 if (skb_vlan_tag_present(skb
))
76 else if (skb
->protocol
== htons(ETH_P_8021Q
))
77 return vlan_eth_hdr(skb
)->h_vlan_encapsulated_proto
;
82 #define IS_VLAN_IP(skb) \
83 (vlan_proto(skb) == htons(ETH_P_IP) && \
84 brnf_filter_vlan_tagged)
86 #define IS_VLAN_IPV6(skb) \
87 (vlan_proto(skb) == htons(ETH_P_IPV6) && \
88 brnf_filter_vlan_tagged)
90 #define IS_VLAN_ARP(skb) \
91 (vlan_proto(skb) == htons(ETH_P_ARP) && \
92 brnf_filter_vlan_tagged)
94 static inline __be16
pppoe_proto(const struct sk_buff
*skb
)
96 return *((__be16
*)(skb_mac_header(skb
) + ETH_HLEN
+
97 sizeof(struct pppoe_hdr
)));
100 #define IS_PPPOE_IP(skb) \
101 (skb->protocol == htons(ETH_P_PPP_SES) && \
102 pppoe_proto(skb) == htons(PPP_IP) && \
103 brnf_filter_pppoe_tagged)
105 #define IS_PPPOE_IPV6(skb) \
106 (skb->protocol == htons(ETH_P_PPP_SES) && \
107 pppoe_proto(skb) == htons(PPP_IPV6) && \
108 brnf_filter_pppoe_tagged)
110 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
111 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
113 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
114 struct brnf_frag_data
{
115 char mac
[NF_BRIDGE_MAX_MAC_HEADER_LENGTH
];
120 static DEFINE_PER_CPU(struct brnf_frag_data
, brnf_frag_data_storage
);
123 static struct nf_bridge_info
*nf_bridge_info_get(const struct sk_buff
*skb
)
125 return skb
->nf_bridge
;
128 static inline struct rtable
*bridge_parent_rtable(const struct net_device
*dev
)
130 struct net_bridge_port
*port
;
132 port
= br_port_get_rcu(dev
);
133 return port
? &port
->br
->fake_rtable
: NULL
;
136 static inline struct net_device
*bridge_parent(const struct net_device
*dev
)
138 struct net_bridge_port
*port
;
140 port
= br_port_get_rcu(dev
);
141 return port
? port
->br
->dev
: NULL
;
144 static inline struct nf_bridge_info
*nf_bridge_alloc(struct sk_buff
*skb
)
146 skb
->nf_bridge
= kzalloc(sizeof(struct nf_bridge_info
), GFP_ATOMIC
);
147 if (likely(skb
->nf_bridge
))
148 atomic_set(&(skb
->nf_bridge
->use
), 1);
150 return skb
->nf_bridge
;
153 static inline struct nf_bridge_info
*nf_bridge_unshare(struct sk_buff
*skb
)
155 struct nf_bridge_info
*nf_bridge
= skb
->nf_bridge
;
157 if (atomic_read(&nf_bridge
->use
) > 1) {
158 struct nf_bridge_info
*tmp
= nf_bridge_alloc(skb
);
161 memcpy(tmp
, nf_bridge
, sizeof(struct nf_bridge_info
));
162 atomic_set(&tmp
->use
, 1);
164 nf_bridge_put(nf_bridge
);
170 static unsigned int nf_bridge_encap_header_len(const struct sk_buff
*skb
)
172 switch (skb
->protocol
) {
173 case __cpu_to_be16(ETH_P_8021Q
):
175 case __cpu_to_be16(ETH_P_PPP_SES
):
176 return PPPOE_SES_HLEN
;
182 static inline void nf_bridge_push_encap_header(struct sk_buff
*skb
)
184 unsigned int len
= nf_bridge_encap_header_len(skb
);
187 skb
->network_header
-= len
;
190 static inline void nf_bridge_pull_encap_header(struct sk_buff
*skb
)
192 unsigned int len
= nf_bridge_encap_header_len(skb
);
195 skb
->network_header
+= len
;
198 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff
*skb
)
200 unsigned int len
= nf_bridge_encap_header_len(skb
);
202 skb_pull_rcsum(skb
, len
);
203 skb
->network_header
+= len
;
206 /* When handing a packet over to the IP layer
207 * check whether we have a skb that is in the
211 static int br_parse_ip_options(struct sk_buff
*skb
)
213 const struct iphdr
*iph
;
214 struct net_device
*dev
= skb
->dev
;
217 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
222 /* Basic sanity checks */
223 if (iph
->ihl
< 5 || iph
->version
!= 4)
226 if (!pskb_may_pull(skb
, iph
->ihl
*4))
230 if (unlikely(ip_fast_csum((u8
*)iph
, iph
->ihl
)))
233 len
= ntohs(iph
->tot_len
);
234 if (skb
->len
< len
) {
235 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INTRUNCATEDPKTS
);
237 } else if (len
< (iph
->ihl
*4))
240 if (pskb_trim_rcsum(skb
, len
)) {
241 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INDISCARDS
);
245 memset(IPCB(skb
), 0, sizeof(struct inet_skb_parm
));
246 /* We should really parse IP options here but until
247 * somebody who actually uses IP options complains to
248 * us we'll just silently ignore the options because
254 IP_INC_STATS_BH(dev_net(dev
), IPSTATS_MIB_INHDRERRORS
);
259 static void nf_bridge_update_protocol(struct sk_buff
*skb
)
261 switch (skb
->nf_bridge
->orig_proto
) {
262 case BRNF_PROTO_8021Q
:
263 skb
->protocol
= htons(ETH_P_8021Q
);
265 case BRNF_PROTO_PPPOE
:
266 skb
->protocol
= htons(ETH_P_PPP_SES
);
268 case BRNF_PROTO_UNCHANGED
:
273 /* PF_BRIDGE/PRE_ROUTING *********************************************/
274 /* Undo the changes made for ip6tables PREROUTING and continue the
275 * bridge PRE_ROUTING hook. */
276 static int br_nf_pre_routing_finish_ipv6(struct sock
*sk
, struct sk_buff
*skb
)
278 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
281 if (nf_bridge
->pkt_otherhost
) {
282 skb
->pkt_type
= PACKET_OTHERHOST
;
283 nf_bridge
->pkt_otherhost
= false;
285 nf_bridge
->mask
^= BRNF_NF_BRIDGE_PREROUTING
;
287 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
292 skb_dst_set_noref(skb
, &rt
->dst
);
294 skb
->dev
= nf_bridge
->physindev
;
295 nf_bridge_update_protocol(skb
);
296 nf_bridge_push_encap_header(skb
);
297 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_PRE_ROUTING
, sk
, skb
,
299 br_handle_frame_finish
, 1);
304 /* Obtain the correct destination MAC address, while preserving the original
305 * source MAC address. If we already know this address, we just copy it. If we
306 * don't, we use the neighbour framework to find out. In both cases, we make
307 * sure that br_handle_frame_finish() is called afterwards.
309 static int br_nf_pre_routing_finish_bridge(struct sock
*sk
, struct sk_buff
*skb
)
311 struct neighbour
*neigh
;
312 struct dst_entry
*dst
;
314 skb
->dev
= bridge_parent(skb
->dev
);
318 neigh
= dst_neigh_lookup_skb(dst
, skb
);
320 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
323 if (neigh
->hh
.hh_len
) {
324 neigh_hh_bridge(&neigh
->hh
, skb
);
325 skb
->dev
= nf_bridge
->physindev
;
326 ret
= br_handle_frame_finish(sk
, skb
);
328 /* the neighbour function below overwrites the complete
329 * MAC header, so we save the Ethernet source address and
332 skb_copy_from_linear_data_offset(skb
,
333 -(ETH_HLEN
-ETH_ALEN
),
334 nf_bridge
->neigh_header
,
336 /* tell br_dev_xmit to continue with forwarding */
337 nf_bridge
->mask
|= BRNF_BRIDGED_DNAT
;
338 /* FIXME Need to refragment */
339 ret
= neigh
->output(neigh
, skb
);
341 neigh_release(neigh
);
349 static bool daddr_was_changed(const struct sk_buff
*skb
,
350 const struct nf_bridge_info
*nf_bridge
)
352 return ip_hdr(skb
)->daddr
!= nf_bridge
->ipv4_daddr
;
355 /* This requires some explaining. If DNAT has taken place,
356 * we will need to fix up the destination Ethernet address.
357 * This is also true when SNAT takes place (for the reply direction).
359 * There are two cases to consider:
360 * 1. The packet was DNAT'ed to a device in the same bridge
361 * port group as it was received on. We can still bridge
363 * 2. The packet was DNAT'ed to a different device, either
364 * a non-bridged device or another bridge port group.
365 * The packet will need to be routed.
367 * The correct way of distinguishing between these two cases is to
368 * call ip_route_input() and to look at skb->dst->dev, which is
369 * changed to the destination device if ip_route_input() succeeds.
371 * Let's first consider the case that ip_route_input() succeeds:
373 * If the output device equals the logical bridge device the packet
374 * came in on, we can consider this bridging. The corresponding MAC
375 * address will be obtained in br_nf_pre_routing_finish_bridge.
376 * Otherwise, the packet is considered to be routed and we just
377 * change the destination MAC address so that the packet will
378 * later be passed up to the IP stack to be routed. For a redirected
379 * packet, ip_route_input() will give back the localhost as output device,
380 * which differs from the bridge device.
382 * Let's now consider the case that ip_route_input() fails:
384 * This can be because the destination address is martian, in which case
385 * the packet will be dropped.
386 * If IP forwarding is disabled, ip_route_input() will fail, while
387 * ip_route_output_key() can return success. The source
388 * address for ip_route_output_key() is set to zero, so ip_route_output_key()
389 * thinks we're handling a locally generated packet and won't care
390 * if IP forwarding is enabled. If the output device equals the logical bridge
391 * device, we proceed as if ip_route_input() succeeded. If it differs from the
392 * logical bridge port or if ip_route_output_key() fails we drop the packet.
394 static int br_nf_pre_routing_finish(struct sock
*sk
, struct sk_buff
*skb
)
396 struct net_device
*dev
= skb
->dev
;
397 struct iphdr
*iph
= ip_hdr(skb
);
398 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
403 frag_max_size
= IPCB(skb
)->frag_max_size
;
404 BR_INPUT_SKB_CB(skb
)->frag_max_size
= frag_max_size
;
406 if (nf_bridge
->pkt_otherhost
) {
407 skb
->pkt_type
= PACKET_OTHERHOST
;
408 nf_bridge
->pkt_otherhost
= false;
410 nf_bridge
->mask
^= BRNF_NF_BRIDGE_PREROUTING
;
411 if (daddr_was_changed(skb
, nf_bridge
)) {
412 if ((err
= ip_route_input(skb
, iph
->daddr
, iph
->saddr
, iph
->tos
, dev
))) {
413 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
415 /* If err equals -EHOSTUNREACH the error is due to a
416 * martian destination or due to the fact that
417 * forwarding is disabled. For most martian packets,
418 * ip_route_output_key() will fail. It won't fail for 2 types of
419 * martian destinations: loopback destinations and destination
420 * 0.0.0.0. In both cases the packet will be dropped because the
421 * destination is the loopback device and not the bridge. */
422 if (err
!= -EHOSTUNREACH
|| !in_dev
|| IN_DEV_FORWARD(in_dev
))
425 rt
= ip_route_output(dev_net(dev
), iph
->daddr
, 0,
426 RT_TOS(iph
->tos
), 0);
428 /* - Bridged-and-DNAT'ed traffic doesn't
429 * require ip_forwarding. */
430 if (rt
->dst
.dev
== dev
) {
431 skb_dst_set(skb
, &rt
->dst
);
440 if (skb_dst(skb
)->dev
== dev
) {
442 skb
->dev
= nf_bridge
->physindev
;
443 nf_bridge_update_protocol(skb
);
444 nf_bridge_push_encap_header(skb
);
445 NF_HOOK_THRESH(NFPROTO_BRIDGE
,
447 sk
, skb
, skb
->dev
, NULL
,
448 br_nf_pre_routing_finish_bridge
,
452 ether_addr_copy(eth_hdr(skb
)->h_dest
, dev
->dev_addr
);
453 skb
->pkt_type
= PACKET_HOST
;
456 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
461 skb_dst_set_noref(skb
, &rt
->dst
);
464 skb
->dev
= nf_bridge
->physindev
;
465 nf_bridge_update_protocol(skb
);
466 nf_bridge_push_encap_header(skb
);
467 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_PRE_ROUTING
, sk
, skb
,
469 br_handle_frame_finish
, 1);
474 static struct net_device
*brnf_get_logical_dev(struct sk_buff
*skb
, const struct net_device
*dev
)
476 struct net_device
*vlan
, *br
;
478 br
= bridge_parent(dev
);
479 if (brnf_pass_vlan_indev
== 0 || !skb_vlan_tag_present(skb
))
482 vlan
= __vlan_find_dev_deep_rcu(br
, skb
->vlan_proto
,
483 skb_vlan_tag_get(skb
) & VLAN_VID_MASK
);
485 return vlan
? vlan
: br
;
488 /* Some common code for IPv4/IPv6 */
489 static struct net_device
*setup_pre_routing(struct sk_buff
*skb
)
491 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
493 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
494 skb
->pkt_type
= PACKET_HOST
;
495 nf_bridge
->pkt_otherhost
= true;
498 nf_bridge
->mask
|= BRNF_NF_BRIDGE_PREROUTING
;
499 nf_bridge
->physindev
= skb
->dev
;
500 skb
->dev
= brnf_get_logical_dev(skb
, skb
->dev
);
502 if (skb
->protocol
== htons(ETH_P_8021Q
))
503 nf_bridge
->orig_proto
= BRNF_PROTO_8021Q
;
504 else if (skb
->protocol
== htons(ETH_P_PPP_SES
))
505 nf_bridge
->orig_proto
= BRNF_PROTO_PPPOE
;
507 /* Must drop socket now because of tproxy. */
512 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
513 static int check_hbh_len(struct sk_buff
*skb
)
515 unsigned char *raw
= (u8
*)(ipv6_hdr(skb
) + 1);
517 const unsigned char *nh
= skb_network_header(skb
);
519 int len
= (raw
[1] + 1) << 3;
521 if ((raw
+ len
) - skb
->data
> skb_headlen(skb
))
528 int optlen
= nh
[off
+ 1] + 2;
539 if (nh
[off
+ 1] != 4 || (off
& 3) != 2)
541 pkt_len
= ntohl(*(__be32
*) (nh
+ off
+ 2));
542 if (pkt_len
<= IPV6_MAXPLEN
||
543 ipv6_hdr(skb
)->payload_len
)
545 if (pkt_len
> skb
->len
- sizeof(struct ipv6hdr
))
547 if (pskb_trim_rcsum(skb
,
548 pkt_len
+ sizeof(struct ipv6hdr
)))
550 nh
= skb_network_header(skb
);
567 /* Replicate the checks that IPv6 does on packet reception and pass the packet
568 * to ip6tables, which doesn't support NAT, so things are fairly simple. */
569 static unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops
*ops
,
571 const struct nf_hook_state
*state
)
573 const struct ipv6hdr
*hdr
;
576 if (skb
->len
< sizeof(struct ipv6hdr
))
579 if (!pskb_may_pull(skb
, sizeof(struct ipv6hdr
)))
584 if (hdr
->version
!= 6)
587 pkt_len
= ntohs(hdr
->payload_len
);
589 if (pkt_len
|| hdr
->nexthdr
!= NEXTHDR_HOP
) {
590 if (pkt_len
+ sizeof(struct ipv6hdr
) > skb
->len
)
592 if (pskb_trim_rcsum(skb
, pkt_len
+ sizeof(struct ipv6hdr
)))
595 if (hdr
->nexthdr
== NEXTHDR_HOP
&& check_hbh_len(skb
))
598 nf_bridge_put(skb
->nf_bridge
);
599 if (!nf_bridge_alloc(skb
))
601 if (!setup_pre_routing(skb
))
604 skb
->protocol
= htons(ETH_P_IPV6
);
605 NF_HOOK(NFPROTO_IPV6
, NF_INET_PRE_ROUTING
, state
->sk
, skb
,
607 br_nf_pre_routing_finish_ipv6
);
612 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
613 * Replicate the checks that IPv4 does on packet reception.
614 * Set skb->dev to the bridge device (i.e. parent of the
615 * receiving device) to make netfilter happy, the REDIRECT
616 * target in particular. Save the original destination IP
617 * address to be able to detect DNAT afterwards. */
618 static unsigned int br_nf_pre_routing(const struct nf_hook_ops
*ops
,
620 const struct nf_hook_state
*state
)
622 struct nf_bridge_info
*nf_bridge
;
623 struct net_bridge_port
*p
;
624 struct net_bridge
*br
;
625 __u32 len
= nf_bridge_encap_header_len(skb
);
627 if (unlikely(!pskb_may_pull(skb
, len
)))
630 p
= br_port_get_rcu(state
->in
);
635 if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
)) {
636 if (!brnf_call_ip6tables
&& !br
->nf_call_ip6tables
)
639 nf_bridge_pull_encap_header_rcsum(skb
);
640 return br_nf_pre_routing_ipv6(ops
, skb
, state
);
643 if (!brnf_call_iptables
&& !br
->nf_call_iptables
)
646 if (!IS_IP(skb
) && !IS_VLAN_IP(skb
) && !IS_PPPOE_IP(skb
))
649 nf_bridge_pull_encap_header_rcsum(skb
);
651 if (br_parse_ip_options(skb
))
654 nf_bridge_put(skb
->nf_bridge
);
655 if (!nf_bridge_alloc(skb
))
657 if (!setup_pre_routing(skb
))
660 nf_bridge
= nf_bridge_info_get(skb
);
661 nf_bridge
->ipv4_daddr
= ip_hdr(skb
)->daddr
;
663 skb
->protocol
= htons(ETH_P_IP
);
665 NF_HOOK(NFPROTO_IPV4
, NF_INET_PRE_ROUTING
, state
->sk
, skb
,
667 br_nf_pre_routing_finish
);
673 /* PF_BRIDGE/LOCAL_IN ************************************************/
674 /* The packet is locally destined, which requires a real
675 * dst_entry, so detach the fake one. On the way up, the
676 * packet would pass through PRE_ROUTING again (which already
677 * took place when the packet entered the bridge), but we
678 * register an IPv4 PRE_ROUTING 'sabotage' hook that will
679 * prevent this from happening. */
680 static unsigned int br_nf_local_in(const struct nf_hook_ops
*ops
,
682 const struct nf_hook_state
*state
)
684 br_drop_fake_rtable(skb
);
688 /* PF_BRIDGE/FORWARD *************************************************/
689 static int br_nf_forward_finish(struct sock
*sk
, struct sk_buff
*skb
)
691 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
692 struct net_device
*in
;
694 if (!IS_ARP(skb
) && !IS_VLAN_ARP(skb
)) {
697 if (skb
->protocol
== htons(ETH_P_IP
)) {
698 frag_max_size
= IPCB(skb
)->frag_max_size
;
699 BR_INPUT_SKB_CB(skb
)->frag_max_size
= frag_max_size
;
702 in
= nf_bridge
->physindev
;
703 if (nf_bridge
->pkt_otherhost
) {
704 skb
->pkt_type
= PACKET_OTHERHOST
;
705 nf_bridge
->pkt_otherhost
= false;
707 nf_bridge_update_protocol(skb
);
709 in
= *((struct net_device
**)(skb
->cb
));
711 nf_bridge_push_encap_header(skb
);
713 NF_HOOK_THRESH(NFPROTO_BRIDGE
, NF_BR_FORWARD
, sk
, skb
,
714 in
, skb
->dev
, br_forward_finish
, 1);
719 /* This is the 'purely bridged' case. For IP, we pass the packet to
720 * netfilter with indev and outdev set to the bridge device,
721 * but we are still able to filter on the 'real' indev/outdev
722 * because of the physdev module. For ARP, indev and outdev are the
724 static unsigned int br_nf_forward_ip(const struct nf_hook_ops
*ops
,
726 const struct nf_hook_state
*state
)
728 struct nf_bridge_info
*nf_bridge
;
729 struct net_device
*parent
;
735 /* Need exclusive nf_bridge_info since we might have multiple
736 * different physoutdevs. */
737 if (!nf_bridge_unshare(skb
))
740 nf_bridge
= nf_bridge_info_get(skb
);
744 parent
= bridge_parent(state
->out
);
748 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
750 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
755 nf_bridge_pull_encap_header(skb
);
757 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
758 skb
->pkt_type
= PACKET_HOST
;
759 nf_bridge
->pkt_otherhost
= true;
762 if (pf
== NFPROTO_IPV4
) {
763 int frag_max
= BR_INPUT_SKB_CB(skb
)->frag_max_size
;
765 if (br_parse_ip_options(skb
))
768 IPCB(skb
)->frag_max_size
= frag_max
;
771 nf_bridge
->physoutdev
= skb
->dev
;
772 if (pf
== NFPROTO_IPV4
)
773 skb
->protocol
= htons(ETH_P_IP
);
775 skb
->protocol
= htons(ETH_P_IPV6
);
777 NF_HOOK(pf
, NF_INET_FORWARD
, NULL
, skb
,
778 brnf_get_logical_dev(skb
, state
->in
),
779 parent
, br_nf_forward_finish
);
784 static unsigned int br_nf_forward_arp(const struct nf_hook_ops
*ops
,
786 const struct nf_hook_state
*state
)
788 struct net_bridge_port
*p
;
789 struct net_bridge
*br
;
790 struct net_device
**d
= (struct net_device
**)(skb
->cb
);
792 p
= br_port_get_rcu(state
->out
);
797 if (!brnf_call_arptables
&& !br
->nf_call_arptables
)
801 if (!IS_VLAN_ARP(skb
))
803 nf_bridge_pull_encap_header(skb
);
806 if (arp_hdr(skb
)->ar_pln
!= 4) {
807 if (IS_VLAN_ARP(skb
))
808 nf_bridge_push_encap_header(skb
);
812 NF_HOOK(NFPROTO_ARP
, NF_ARP_FORWARD
, state
->sk
, skb
,
813 state
->in
, state
->out
, br_nf_forward_finish
);
818 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
819 static int br_nf_push_frag_xmit(struct sock
*sk
, struct sk_buff
*skb
)
821 struct brnf_frag_data
*data
;
824 data
= this_cpu_ptr(&brnf_frag_data_storage
);
825 err
= skb_cow_head(skb
, data
->size
);
832 skb_copy_to_linear_data_offset(skb
, -data
->size
, data
->mac
, data
->size
);
833 __skb_push(skb
, data
->encap_size
);
835 return br_dev_queue_push_xmit(sk
, skb
);
838 static int br_nf_dev_queue_xmit(struct sock
*sk
, struct sk_buff
*skb
)
842 unsigned int mtu_reserved
;
844 if (skb_is_gso(skb
) || skb
->protocol
!= htons(ETH_P_IP
))
845 return br_dev_queue_push_xmit(sk
, skb
);
847 mtu_reserved
= nf_bridge_mtu_reduction(skb
);
848 /* This is wrong! We should preserve the original fragment
849 * boundaries by preserving frag_list rather than refragmenting.
851 if (skb
->len
+ mtu_reserved
> skb
->dev
->mtu
) {
852 struct brnf_frag_data
*data
;
854 frag_max_size
= BR_INPUT_SKB_CB(skb
)->frag_max_size
;
855 if (br_parse_ip_options(skb
))
856 /* Drop invalid packet */
858 IPCB(skb
)->frag_max_size
= frag_max_size
;
860 nf_bridge_update_protocol(skb
);
862 data
= this_cpu_ptr(&brnf_frag_data_storage
);
863 data
->encap_size
= nf_bridge_encap_header_len(skb
);
864 data
->size
= ETH_HLEN
+ data
->encap_size
;
866 skb_copy_from_linear_data_offset(skb
, -data
->size
, data
->mac
,
869 ret
= ip_fragment(sk
, skb
, br_nf_push_frag_xmit
);
871 ret
= br_dev_queue_push_xmit(sk
, skb
);
877 static int br_nf_dev_queue_xmit(struct sock
*sk
, struct sk_buff
*skb
)
879 return br_dev_queue_push_xmit(sk
, skb
);
883 /* PF_BRIDGE/POST_ROUTING ********************************************/
884 static unsigned int br_nf_post_routing(const struct nf_hook_ops
*ops
,
886 const struct nf_hook_state
*state
)
888 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
889 struct net_device
*realoutdev
= bridge_parent(skb
->dev
);
892 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
893 * on a bridge, but was delivered locally and is now being routed:
895 * POST_ROUTING was already invoked from the ip stack.
897 if (!nf_bridge
|| !nf_bridge
->physoutdev
)
903 if (IS_IP(skb
) || IS_VLAN_IP(skb
) || IS_PPPOE_IP(skb
))
905 else if (IS_IPV6(skb
) || IS_VLAN_IPV6(skb
) || IS_PPPOE_IPV6(skb
))
910 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
911 * about the value of skb->pkt_type. */
912 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
913 skb
->pkt_type
= PACKET_HOST
;
914 nf_bridge
->pkt_otherhost
= true;
917 nf_bridge_pull_encap_header(skb
);
918 if (pf
== NFPROTO_IPV4
)
919 skb
->protocol
= htons(ETH_P_IP
);
921 skb
->protocol
= htons(ETH_P_IPV6
);
923 NF_HOOK(pf
, NF_INET_POST_ROUTING
, state
->sk
, skb
,
925 br_nf_dev_queue_xmit
);
930 /* IP/SABOTAGE *****************************************************/
931 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
932 * for the second time. */
933 static unsigned int ip_sabotage_in(const struct nf_hook_ops
*ops
,
935 const struct nf_hook_state
*state
)
937 if (skb
->nf_bridge
&&
938 !(skb
->nf_bridge
->mask
& BRNF_NF_BRIDGE_PREROUTING
)) {
945 /* This is called when br_netfilter has called into iptables/netfilter,
946 * and DNAT has taken place on a bridge-forwarded packet.
948 * neigh->output has created a new MAC header, with local br0 MAC
951 * This restores the original MAC saddr of the bridged packet
952 * before invoking bridge forward logic to transmit the packet.
954 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff
*skb
)
956 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
958 skb_pull(skb
, ETH_HLEN
);
959 nf_bridge
->mask
&= ~BRNF_BRIDGED_DNAT
;
961 BUILD_BUG_ON(sizeof(nf_bridge
->neigh_header
) != (ETH_HLEN
- ETH_ALEN
));
963 skb_copy_to_linear_data_offset(skb
, -(ETH_HLEN
- ETH_ALEN
),
964 nf_bridge
->neigh_header
,
965 ETH_HLEN
- ETH_ALEN
);
966 skb
->dev
= nf_bridge
->physindev
;
967 br_handle_frame_finish(NULL
, skb
);
970 static int br_nf_dev_xmit(struct sk_buff
*skb
)
972 if (skb
->nf_bridge
&& (skb
->nf_bridge
->mask
& BRNF_BRIDGED_DNAT
)) {
973 br_nf_pre_routing_finish_bridge_slow(skb
);
979 static const struct nf_br_ops br_ops
= {
980 .br_dev_xmit_hook
= br_nf_dev_xmit
,
983 void br_netfilter_enable(void)
986 EXPORT_SYMBOL_GPL(br_netfilter_enable
);
988 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
989 * br_dev_queue_push_xmit is called afterwards */
990 static struct nf_hook_ops br_nf_ops
[] __read_mostly
= {
992 .hook
= br_nf_pre_routing
,
993 .owner
= THIS_MODULE
,
994 .pf
= NFPROTO_BRIDGE
,
995 .hooknum
= NF_BR_PRE_ROUTING
,
996 .priority
= NF_BR_PRI_BRNF
,
999 .hook
= br_nf_local_in
,
1000 .owner
= THIS_MODULE
,
1001 .pf
= NFPROTO_BRIDGE
,
1002 .hooknum
= NF_BR_LOCAL_IN
,
1003 .priority
= NF_BR_PRI_BRNF
,
1006 .hook
= br_nf_forward_ip
,
1007 .owner
= THIS_MODULE
,
1008 .pf
= NFPROTO_BRIDGE
,
1009 .hooknum
= NF_BR_FORWARD
,
1010 .priority
= NF_BR_PRI_BRNF
- 1,
1013 .hook
= br_nf_forward_arp
,
1014 .owner
= THIS_MODULE
,
1015 .pf
= NFPROTO_BRIDGE
,
1016 .hooknum
= NF_BR_FORWARD
,
1017 .priority
= NF_BR_PRI_BRNF
,
1020 .hook
= br_nf_post_routing
,
1021 .owner
= THIS_MODULE
,
1022 .pf
= NFPROTO_BRIDGE
,
1023 .hooknum
= NF_BR_POST_ROUTING
,
1024 .priority
= NF_BR_PRI_LAST
,
1027 .hook
= ip_sabotage_in
,
1028 .owner
= THIS_MODULE
,
1030 .hooknum
= NF_INET_PRE_ROUTING
,
1031 .priority
= NF_IP_PRI_FIRST
,
1034 .hook
= ip_sabotage_in
,
1035 .owner
= THIS_MODULE
,
1037 .hooknum
= NF_INET_PRE_ROUTING
,
1038 .priority
= NF_IP6_PRI_FIRST
,
1042 #ifdef CONFIG_SYSCTL
1044 int brnf_sysctl_call_tables(struct ctl_table
*ctl
, int write
,
1045 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1049 ret
= proc_dointvec(ctl
, write
, buffer
, lenp
, ppos
);
1051 if (write
&& *(int *)(ctl
->data
))
1052 *(int *)(ctl
->data
) = 1;
1056 static struct ctl_table brnf_table
[] = {
1058 .procname
= "bridge-nf-call-arptables",
1059 .data
= &brnf_call_arptables
,
1060 .maxlen
= sizeof(int),
1062 .proc_handler
= brnf_sysctl_call_tables
,
1065 .procname
= "bridge-nf-call-iptables",
1066 .data
= &brnf_call_iptables
,
1067 .maxlen
= sizeof(int),
1069 .proc_handler
= brnf_sysctl_call_tables
,
1072 .procname
= "bridge-nf-call-ip6tables",
1073 .data
= &brnf_call_ip6tables
,
1074 .maxlen
= sizeof(int),
1076 .proc_handler
= brnf_sysctl_call_tables
,
1079 .procname
= "bridge-nf-filter-vlan-tagged",
1080 .data
= &brnf_filter_vlan_tagged
,
1081 .maxlen
= sizeof(int),
1083 .proc_handler
= brnf_sysctl_call_tables
,
1086 .procname
= "bridge-nf-filter-pppoe-tagged",
1087 .data
= &brnf_filter_pppoe_tagged
,
1088 .maxlen
= sizeof(int),
1090 .proc_handler
= brnf_sysctl_call_tables
,
1093 .procname
= "bridge-nf-pass-vlan-input-dev",
1094 .data
= &brnf_pass_vlan_indev
,
1095 .maxlen
= sizeof(int),
1097 .proc_handler
= brnf_sysctl_call_tables
,
1103 static int __init
br_netfilter_init(void)
1107 ret
= nf_register_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1111 #ifdef CONFIG_SYSCTL
1112 brnf_sysctl_header
= register_net_sysctl(&init_net
, "net/bridge", brnf_table
);
1113 if (brnf_sysctl_header
== NULL
) {
1115 "br_netfilter: can't register to sysctl.\n");
1116 nf_unregister_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1120 RCU_INIT_POINTER(nf_br_ops
, &br_ops
);
1121 printk(KERN_NOTICE
"Bridge firewalling registered\n");
1125 static void __exit
br_netfilter_fini(void)
1127 RCU_INIT_POINTER(nf_br_ops
, NULL
);
1128 nf_unregister_hooks(br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1129 #ifdef CONFIG_SYSCTL
1130 unregister_net_sysctl_table(brnf_sysctl_header
);
1134 module_init(br_netfilter_init
);
1135 module_exit(br_netfilter_fini
);
1137 MODULE_LICENSE("GPL");
1138 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1139 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1140 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");