1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Linux ethernet bridge
7 * Lennert Buytenhek <buytenh@gnu.org>
8 * Bart De Schuymer <bdschuym@pandora.be>
10 * Lennert dedicates this file to Kerstin Wurdinger.
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
17 #include <linux/netdevice.h>
18 #include <linux/skbuff.h>
19 #include <linux/if_arp.h>
20 #include <linux/if_ether.h>
21 #include <linux/if_vlan.h>
22 #include <linux/if_pppox.h>
23 #include <linux/ppp_defs.h>
24 #include <linux/netfilter_bridge.h>
25 #include <uapi/linux/netfilter_bridge.h>
26 #include <linux/netfilter_ipv4.h>
27 #include <linux/netfilter_ipv6.h>
28 #include <linux/netfilter_arp.h>
29 #include <linux/in_route.h>
30 #include <linux/rculist.h>
31 #include <linux/inetdevice.h>
35 #include <net/addrconf.h>
36 #include <net/route.h>
37 #include <net/netfilter/br_netfilter.h>
38 #include <net/netns/generic.h>
40 #include <linux/uaccess.h>
41 #include "br_private.h"
43 #include <linux/sysctl.h>
46 static unsigned int brnf_net_id __read_mostly
;
52 struct ctl_table_header
*ctl_hdr
;
55 /* default value is 1 */
60 /* default value is 0 */
61 int filter_vlan_tagged
;
62 int filter_pppoe_tagged
;
67 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
69 #define IS_IPV6(skb) \
70 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
73 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
75 static inline __be16
vlan_proto(const struct sk_buff
*skb
)
77 if (skb_vlan_tag_present(skb
))
79 else if (skb
->protocol
== htons(ETH_P_8021Q
))
80 return vlan_eth_hdr(skb
)->h_vlan_encapsulated_proto
;
85 static inline bool is_vlan_ip(const struct sk_buff
*skb
, const struct net
*net
)
87 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
89 return vlan_proto(skb
) == htons(ETH_P_IP
) && brnet
->filter_vlan_tagged
;
92 static inline bool is_vlan_ipv6(const struct sk_buff
*skb
,
93 const struct net
*net
)
95 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
97 return vlan_proto(skb
) == htons(ETH_P_IPV6
) &&
98 brnet
->filter_vlan_tagged
;
101 static inline bool is_vlan_arp(const struct sk_buff
*skb
, const struct net
*net
)
103 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
105 return vlan_proto(skb
) == htons(ETH_P_ARP
) && brnet
->filter_vlan_tagged
;
108 static inline __be16
pppoe_proto(const struct sk_buff
*skb
)
110 return *((__be16
*)(skb_mac_header(skb
) + ETH_HLEN
+
111 sizeof(struct pppoe_hdr
)));
114 static inline bool is_pppoe_ip(const struct sk_buff
*skb
, const struct net
*net
)
116 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
118 return skb
->protocol
== htons(ETH_P_PPP_SES
) &&
119 pppoe_proto(skb
) == htons(PPP_IP
) && brnet
->filter_pppoe_tagged
;
122 static inline bool is_pppoe_ipv6(const struct sk_buff
*skb
,
123 const struct net
*net
)
125 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
127 return skb
->protocol
== htons(ETH_P_PPP_SES
) &&
128 pppoe_proto(skb
) == htons(PPP_IPV6
) &&
129 brnet
->filter_pppoe_tagged
;
132 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
133 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
135 struct brnf_frag_data
{
136 char mac
[NF_BRIDGE_MAX_MAC_HEADER_LENGTH
];
143 static DEFINE_PER_CPU(struct brnf_frag_data
, brnf_frag_data_storage
);
145 static void nf_bridge_info_free(struct sk_buff
*skb
)
147 skb_ext_del(skb
, SKB_EXT_BRIDGE_NF
);
150 static inline struct net_device
*bridge_parent(const struct net_device
*dev
)
152 struct net_bridge_port
*port
;
154 port
= br_port_get_rcu(dev
);
155 return port
? port
->br
->dev
: NULL
;
158 static inline struct nf_bridge_info
*nf_bridge_unshare(struct sk_buff
*skb
)
160 return skb_ext_add(skb
, SKB_EXT_BRIDGE_NF
);
163 unsigned int nf_bridge_encap_header_len(const struct sk_buff
*skb
)
165 switch (skb
->protocol
) {
166 case __cpu_to_be16(ETH_P_8021Q
):
168 case __cpu_to_be16(ETH_P_PPP_SES
):
169 return PPPOE_SES_HLEN
;
175 static inline void nf_bridge_pull_encap_header(struct sk_buff
*skb
)
177 unsigned int len
= nf_bridge_encap_header_len(skb
);
180 skb
->network_header
+= len
;
183 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff
*skb
)
185 unsigned int len
= nf_bridge_encap_header_len(skb
);
187 skb_pull_rcsum(skb
, len
);
188 skb
->network_header
+= len
;
191 /* When handing a packet over to the IP layer
192 * check whether we have a skb that is in the
196 static int br_validate_ipv4(struct net
*net
, struct sk_buff
*skb
)
198 const struct iphdr
*iph
;
201 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
206 /* Basic sanity checks */
207 if (iph
->ihl
< 5 || iph
->version
!= 4)
210 if (!pskb_may_pull(skb
, iph
->ihl
*4))
214 if (unlikely(ip_fast_csum((u8
*)iph
, iph
->ihl
)))
217 len
= ntohs(iph
->tot_len
);
218 if (skb
->len
< len
) {
219 __IP_INC_STATS(net
, IPSTATS_MIB_INTRUNCATEDPKTS
);
221 } else if (len
< (iph
->ihl
*4))
224 if (pskb_trim_rcsum(skb
, len
)) {
225 __IP_INC_STATS(net
, IPSTATS_MIB_INDISCARDS
);
229 memset(IPCB(skb
), 0, sizeof(struct inet_skb_parm
));
230 /* We should really parse IP options here but until
231 * somebody who actually uses IP options complains to
232 * us we'll just silently ignore the options because
238 __IP_INC_STATS(net
, IPSTATS_MIB_CSUMERRORS
);
240 __IP_INC_STATS(net
, IPSTATS_MIB_INHDRERRORS
);
245 void nf_bridge_update_protocol(struct sk_buff
*skb
)
247 const struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
249 switch (nf_bridge
->orig_proto
) {
250 case BRNF_PROTO_8021Q
:
251 skb
->protocol
= htons(ETH_P_8021Q
);
253 case BRNF_PROTO_PPPOE
:
254 skb
->protocol
= htons(ETH_P_PPP_SES
);
256 case BRNF_PROTO_UNCHANGED
:
261 /* Obtain the correct destination MAC address, while preserving the original
262 * source MAC address. If we already know this address, we just copy it. If we
263 * don't, we use the neighbour framework to find out. In both cases, we make
264 * sure that br_handle_frame_finish() is called afterwards.
266 int br_nf_pre_routing_finish_bridge(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
268 struct neighbour
*neigh
;
269 struct dst_entry
*dst
;
271 skb
->dev
= bridge_parent(skb
->dev
);
275 neigh
= dst_neigh_lookup_skb(dst
, skb
);
277 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
280 if ((neigh
->nud_state
& NUD_CONNECTED
) && neigh
->hh
.hh_len
) {
281 neigh_hh_bridge(&neigh
->hh
, skb
);
282 skb
->dev
= nf_bridge
->physindev
;
283 ret
= br_handle_frame_finish(net
, sk
, skb
);
285 /* the neighbour function below overwrites the complete
286 * MAC header, so we save the Ethernet source address and
289 skb_copy_from_linear_data_offset(skb
,
290 -(ETH_HLEN
-ETH_ALEN
),
291 nf_bridge
->neigh_header
,
293 /* tell br_dev_xmit to continue with forwarding */
294 nf_bridge
->bridged_dnat
= 1;
295 /* FIXME Need to refragment */
296 ret
= neigh
->output(neigh
, skb
);
298 neigh_release(neigh
);
307 br_nf_ipv4_daddr_was_changed(const struct sk_buff
*skb
,
308 const struct nf_bridge_info
*nf_bridge
)
310 return ip_hdr(skb
)->daddr
!= nf_bridge
->ipv4_daddr
;
313 /* This requires some explaining. If DNAT has taken place,
314 * we will need to fix up the destination Ethernet address.
315 * This is also true when SNAT takes place (for the reply direction).
317 * There are two cases to consider:
318 * 1. The packet was DNAT'ed to a device in the same bridge
319 * port group as it was received on. We can still bridge
321 * 2. The packet was DNAT'ed to a different device, either
322 * a non-bridged device or another bridge port group.
323 * The packet will need to be routed.
325 * The correct way of distinguishing between these two cases is to
326 * call ip_route_input() and to look at skb->dst->dev, which is
327 * changed to the destination device if ip_route_input() succeeds.
329 * Let's first consider the case that ip_route_input() succeeds:
331 * If the output device equals the logical bridge device the packet
332 * came in on, we can consider this bridging. The corresponding MAC
333 * address will be obtained in br_nf_pre_routing_finish_bridge.
334 * Otherwise, the packet is considered to be routed and we just
335 * change the destination MAC address so that the packet will
336 * later be passed up to the IP stack to be routed. For a redirected
337 * packet, ip_route_input() will give back the localhost as output device,
338 * which differs from the bridge device.
340 * Let's now consider the case that ip_route_input() fails:
342 * This can be because the destination address is martian, in which case
343 * the packet will be dropped.
344 * If IP forwarding is disabled, ip_route_input() will fail, while
345 * ip_route_output_key() can return success. The source
346 * address for ip_route_output_key() is set to zero, so ip_route_output_key()
347 * thinks we're handling a locally generated packet and won't care
348 * if IP forwarding is enabled. If the output device equals the logical bridge
349 * device, we proceed as if ip_route_input() succeeded. If it differs from the
350 * logical bridge port or if ip_route_output_key() fails we drop the packet.
352 static int br_nf_pre_routing_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
354 struct net_device
*dev
= skb
->dev
;
355 struct iphdr
*iph
= ip_hdr(skb
);
356 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
360 nf_bridge
->frag_max_size
= IPCB(skb
)->frag_max_size
;
362 if (nf_bridge
->pkt_otherhost
) {
363 skb
->pkt_type
= PACKET_OTHERHOST
;
364 nf_bridge
->pkt_otherhost
= false;
366 nf_bridge
->in_prerouting
= 0;
367 if (br_nf_ipv4_daddr_was_changed(skb
, nf_bridge
)) {
368 if ((err
= ip_route_input(skb
, iph
->daddr
, iph
->saddr
, iph
->tos
, dev
))) {
369 struct in_device
*in_dev
= __in_dev_get_rcu(dev
);
371 /* If err equals -EHOSTUNREACH the error is due to a
372 * martian destination or due to the fact that
373 * forwarding is disabled. For most martian packets,
374 * ip_route_output_key() will fail. It won't fail for 2 types of
375 * martian destinations: loopback destinations and destination
376 * 0.0.0.0. In both cases the packet will be dropped because the
377 * destination is the loopback device and not the bridge. */
378 if (err
!= -EHOSTUNREACH
|| !in_dev
|| IN_DEV_FORWARD(in_dev
))
381 rt
= ip_route_output(net
, iph
->daddr
, 0,
382 RT_TOS(iph
->tos
), 0);
384 /* - Bridged-and-DNAT'ed traffic doesn't
385 * require ip_forwarding. */
386 if (rt
->dst
.dev
== dev
) {
387 skb_dst_set(skb
, &rt
->dst
);
396 if (skb_dst(skb
)->dev
== dev
) {
398 skb
->dev
= nf_bridge
->physindev
;
399 nf_bridge_update_protocol(skb
);
400 nf_bridge_push_encap_header(skb
);
401 br_nf_hook_thresh(NF_BR_PRE_ROUTING
,
402 net
, sk
, skb
, skb
->dev
,
404 br_nf_pre_routing_finish_bridge
);
407 ether_addr_copy(eth_hdr(skb
)->h_dest
, dev
->dev_addr
);
408 skb
->pkt_type
= PACKET_HOST
;
411 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
416 skb_dst_set_noref(skb
, &rt
->dst
);
419 skb
->dev
= nf_bridge
->physindev
;
420 nf_bridge_update_protocol(skb
);
421 nf_bridge_push_encap_header(skb
);
422 br_nf_hook_thresh(NF_BR_PRE_ROUTING
, net
, sk
, skb
, skb
->dev
, NULL
,
423 br_handle_frame_finish
);
427 static struct net_device
*brnf_get_logical_dev(struct sk_buff
*skb
,
428 const struct net_device
*dev
,
429 const struct net
*net
)
431 struct net_device
*vlan
, *br
;
432 struct brnf_net
*brnet
= net_generic(net
, brnf_net_id
);
434 br
= bridge_parent(dev
);
436 if (brnet
->pass_vlan_indev
== 0 || !skb_vlan_tag_present(skb
))
439 vlan
= __vlan_find_dev_deep_rcu(br
, skb
->vlan_proto
,
440 skb_vlan_tag_get(skb
) & VLAN_VID_MASK
);
442 return vlan
? vlan
: br
;
445 /* Some common code for IPv4/IPv6 */
446 struct net_device
*setup_pre_routing(struct sk_buff
*skb
, const struct net
*net
)
448 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
450 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
451 skb
->pkt_type
= PACKET_HOST
;
452 nf_bridge
->pkt_otherhost
= true;
455 nf_bridge
->in_prerouting
= 1;
456 nf_bridge
->physindev
= skb
->dev
;
457 skb
->dev
= brnf_get_logical_dev(skb
, skb
->dev
, net
);
459 if (skb
->protocol
== htons(ETH_P_8021Q
))
460 nf_bridge
->orig_proto
= BRNF_PROTO_8021Q
;
461 else if (skb
->protocol
== htons(ETH_P_PPP_SES
))
462 nf_bridge
->orig_proto
= BRNF_PROTO_PPPOE
;
464 /* Must drop socket now because of tproxy. */
469 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
470 * Replicate the checks that IPv4 does on packet reception.
471 * Set skb->dev to the bridge device (i.e. parent of the
472 * receiving device) to make netfilter happy, the REDIRECT
473 * target in particular. Save the original destination IP
474 * address to be able to detect DNAT afterwards. */
475 static unsigned int br_nf_pre_routing(void *priv
,
477 const struct nf_hook_state
*state
)
479 struct nf_bridge_info
*nf_bridge
;
480 struct net_bridge_port
*p
;
481 struct net_bridge
*br
;
482 __u32 len
= nf_bridge_encap_header_len(skb
);
483 struct brnf_net
*brnet
;
485 if (unlikely(!pskb_may_pull(skb
, len
)))
488 p
= br_port_get_rcu(state
->in
);
493 brnet
= net_generic(state
->net
, brnf_net_id
);
494 if (IS_IPV6(skb
) || is_vlan_ipv6(skb
, state
->net
) ||
495 is_pppoe_ipv6(skb
, state
->net
)) {
496 if (!brnet
->call_ip6tables
&&
497 !br_opt_get(br
, BROPT_NF_CALL_IP6TABLES
))
499 if (!ipv6_mod_enabled()) {
500 pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
504 nf_bridge_pull_encap_header_rcsum(skb
);
505 return br_nf_pre_routing_ipv6(priv
, skb
, state
);
508 if (!brnet
->call_iptables
&& !br_opt_get(br
, BROPT_NF_CALL_IPTABLES
))
511 if (!IS_IP(skb
) && !is_vlan_ip(skb
, state
->net
) &&
512 !is_pppoe_ip(skb
, state
->net
))
515 nf_bridge_pull_encap_header_rcsum(skb
);
517 if (br_validate_ipv4(state
->net
, skb
))
520 if (!nf_bridge_alloc(skb
))
522 if (!setup_pre_routing(skb
, state
->net
))
525 nf_bridge
= nf_bridge_info_get(skb
);
526 nf_bridge
->ipv4_daddr
= ip_hdr(skb
)->daddr
;
528 skb
->protocol
= htons(ETH_P_IP
);
529 skb
->transport_header
= skb
->network_header
+ ip_hdr(skb
)->ihl
* 4;
531 NF_HOOK(NFPROTO_IPV4
, NF_INET_PRE_ROUTING
, state
->net
, state
->sk
, skb
,
533 br_nf_pre_routing_finish
);
539 /* PF_BRIDGE/FORWARD *************************************************/
540 static int br_nf_forward_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
542 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
543 struct net_device
*in
;
545 if (!IS_ARP(skb
) && !is_vlan_arp(skb
, net
)) {
547 if (skb
->protocol
== htons(ETH_P_IP
))
548 nf_bridge
->frag_max_size
= IPCB(skb
)->frag_max_size
;
550 if (skb
->protocol
== htons(ETH_P_IPV6
))
551 nf_bridge
->frag_max_size
= IP6CB(skb
)->frag_max_size
;
553 in
= nf_bridge
->physindev
;
554 if (nf_bridge
->pkt_otherhost
) {
555 skb
->pkt_type
= PACKET_OTHERHOST
;
556 nf_bridge
->pkt_otherhost
= false;
558 nf_bridge_update_protocol(skb
);
560 in
= *((struct net_device
**)(skb
->cb
));
562 nf_bridge_push_encap_header(skb
);
564 br_nf_hook_thresh(NF_BR_FORWARD
, net
, sk
, skb
, in
, skb
->dev
,
570 /* This is the 'purely bridged' case. For IP, we pass the packet to
571 * netfilter with indev and outdev set to the bridge device,
572 * but we are still able to filter on the 'real' indev/outdev
573 * because of the physdev module. For ARP, indev and outdev are the
575 static unsigned int br_nf_forward_ip(void *priv
,
577 const struct nf_hook_state
*state
)
579 struct nf_bridge_info
*nf_bridge
;
580 struct net_device
*parent
;
583 nf_bridge
= nf_bridge_info_get(skb
);
587 /* Need exclusive nf_bridge_info since we might have multiple
588 * different physoutdevs. */
589 if (!nf_bridge_unshare(skb
))
592 nf_bridge
= nf_bridge_info_get(skb
);
596 parent
= bridge_parent(state
->out
);
600 if (IS_IP(skb
) || is_vlan_ip(skb
, state
->net
) ||
601 is_pppoe_ip(skb
, state
->net
))
603 else if (IS_IPV6(skb
) || is_vlan_ipv6(skb
, state
->net
) ||
604 is_pppoe_ipv6(skb
, state
->net
))
609 nf_bridge_pull_encap_header(skb
);
611 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
612 skb
->pkt_type
= PACKET_HOST
;
613 nf_bridge
->pkt_otherhost
= true;
616 if (pf
== NFPROTO_IPV4
) {
617 if (br_validate_ipv4(state
->net
, skb
))
619 IPCB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
622 if (pf
== NFPROTO_IPV6
) {
623 if (br_validate_ipv6(state
->net
, skb
))
625 IP6CB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
628 nf_bridge
->physoutdev
= skb
->dev
;
629 if (pf
== NFPROTO_IPV4
)
630 skb
->protocol
= htons(ETH_P_IP
);
632 skb
->protocol
= htons(ETH_P_IPV6
);
634 NF_HOOK(pf
, NF_INET_FORWARD
, state
->net
, NULL
, skb
,
635 brnf_get_logical_dev(skb
, state
->in
, state
->net
),
636 parent
, br_nf_forward_finish
);
641 static unsigned int br_nf_forward_arp(void *priv
,
643 const struct nf_hook_state
*state
)
645 struct net_bridge_port
*p
;
646 struct net_bridge
*br
;
647 struct net_device
**d
= (struct net_device
**)(skb
->cb
);
648 struct brnf_net
*brnet
;
650 p
= br_port_get_rcu(state
->out
);
655 brnet
= net_generic(state
->net
, brnf_net_id
);
656 if (!brnet
->call_arptables
&& !br_opt_get(br
, BROPT_NF_CALL_ARPTABLES
))
660 if (!is_vlan_arp(skb
, state
->net
))
662 nf_bridge_pull_encap_header(skb
);
665 if (unlikely(!pskb_may_pull(skb
, sizeof(struct arphdr
))))
668 if (arp_hdr(skb
)->ar_pln
!= 4) {
669 if (is_vlan_arp(skb
, state
->net
))
670 nf_bridge_push_encap_header(skb
);
674 NF_HOOK(NFPROTO_ARP
, NF_ARP_FORWARD
, state
->net
, state
->sk
, skb
,
675 state
->in
, state
->out
, br_nf_forward_finish
);
680 static int br_nf_push_frag_xmit(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
682 struct brnf_frag_data
*data
;
685 data
= this_cpu_ptr(&brnf_frag_data_storage
);
686 err
= skb_cow_head(skb
, data
->size
);
693 if (data
->vlan_proto
)
694 __vlan_hwaccel_put_tag(skb
, data
->vlan_proto
, data
->vlan_tci
);
696 skb_copy_to_linear_data_offset(skb
, -data
->size
, data
->mac
, data
->size
);
697 __skb_push(skb
, data
->encap_size
);
699 nf_bridge_info_free(skb
);
700 return br_dev_queue_push_xmit(net
, sk
, skb
);
704 br_nf_ip_fragment(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
,
705 int (*output
)(struct net
*, struct sock
*, struct sk_buff
*))
707 unsigned int mtu
= ip_skb_dst_mtu(sk
, skb
);
708 struct iphdr
*iph
= ip_hdr(skb
);
710 if (unlikely(((iph
->frag_off
& htons(IP_DF
)) && !skb
->ignore_df
) ||
711 (IPCB(skb
)->frag_max_size
&&
712 IPCB(skb
)->frag_max_size
> mtu
))) {
713 IP_INC_STATS(net
, IPSTATS_MIB_FRAGFAILS
);
718 return ip_do_fragment(net
, sk
, skb
, output
);
721 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff
*skb
)
723 const struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
725 if (nf_bridge
->orig_proto
== BRNF_PROTO_PPPOE
)
726 return PPPOE_SES_HLEN
;
730 static int br_nf_dev_queue_xmit(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
732 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
733 unsigned int mtu
, mtu_reserved
;
735 mtu_reserved
= nf_bridge_mtu_reduction(skb
);
738 if (nf_bridge
->frag_max_size
&& nf_bridge
->frag_max_size
< mtu
)
739 mtu
= nf_bridge
->frag_max_size
;
741 if (skb_is_gso(skb
) || skb
->len
+ mtu_reserved
<= mtu
) {
742 nf_bridge_info_free(skb
);
743 return br_dev_queue_push_xmit(net
, sk
, skb
);
746 /* This is wrong! We should preserve the original fragment
747 * boundaries by preserving frag_list rather than refragmenting.
749 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4
) &&
750 skb
->protocol
== htons(ETH_P_IP
)) {
751 struct brnf_frag_data
*data
;
753 if (br_validate_ipv4(net
, skb
))
756 IPCB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
758 nf_bridge_update_protocol(skb
);
760 data
= this_cpu_ptr(&brnf_frag_data_storage
);
762 if (skb_vlan_tag_present(skb
)) {
763 data
->vlan_tci
= skb
->vlan_tci
;
764 data
->vlan_proto
= skb
->vlan_proto
;
766 data
->vlan_proto
= 0;
769 data
->encap_size
= nf_bridge_encap_header_len(skb
);
770 data
->size
= ETH_HLEN
+ data
->encap_size
;
772 skb_copy_from_linear_data_offset(skb
, -data
->size
, data
->mac
,
775 return br_nf_ip_fragment(net
, sk
, skb
, br_nf_push_frag_xmit
);
777 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6
) &&
778 skb
->protocol
== htons(ETH_P_IPV6
)) {
779 const struct nf_ipv6_ops
*v6ops
= nf_get_ipv6_ops();
780 struct brnf_frag_data
*data
;
782 if (br_validate_ipv6(net
, skb
))
785 IP6CB(skb
)->frag_max_size
= nf_bridge
->frag_max_size
;
787 nf_bridge_update_protocol(skb
);
789 data
= this_cpu_ptr(&brnf_frag_data_storage
);
790 data
->encap_size
= nf_bridge_encap_header_len(skb
);
791 data
->size
= ETH_HLEN
+ data
->encap_size
;
793 skb_copy_from_linear_data_offset(skb
, -data
->size
, data
->mac
,
797 return v6ops
->fragment(net
, sk
, skb
, br_nf_push_frag_xmit
);
802 nf_bridge_info_free(skb
);
803 return br_dev_queue_push_xmit(net
, sk
, skb
);
809 /* PF_BRIDGE/POST_ROUTING ********************************************/
810 static unsigned int br_nf_post_routing(void *priv
,
812 const struct nf_hook_state
*state
)
814 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
815 struct net_device
*realoutdev
= bridge_parent(skb
->dev
);
818 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
819 * on a bridge, but was delivered locally and is now being routed:
821 * POST_ROUTING was already invoked from the ip stack.
823 if (!nf_bridge
|| !nf_bridge
->physoutdev
)
829 if (IS_IP(skb
) || is_vlan_ip(skb
, state
->net
) ||
830 is_pppoe_ip(skb
, state
->net
))
832 else if (IS_IPV6(skb
) || is_vlan_ipv6(skb
, state
->net
) ||
833 is_pppoe_ipv6(skb
, state
->net
))
838 /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
839 * about the value of skb->pkt_type. */
840 if (skb
->pkt_type
== PACKET_OTHERHOST
) {
841 skb
->pkt_type
= PACKET_HOST
;
842 nf_bridge
->pkt_otherhost
= true;
845 nf_bridge_pull_encap_header(skb
);
846 if (pf
== NFPROTO_IPV4
)
847 skb
->protocol
= htons(ETH_P_IP
);
849 skb
->protocol
= htons(ETH_P_IPV6
);
851 NF_HOOK(pf
, NF_INET_POST_ROUTING
, state
->net
, state
->sk
, skb
,
853 br_nf_dev_queue_xmit
);
858 /* IP/SABOTAGE *****************************************************/
859 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
860 * for the second time. */
861 static unsigned int ip_sabotage_in(void *priv
,
863 const struct nf_hook_state
*state
)
865 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
867 if (nf_bridge
&& !nf_bridge
->in_prerouting
&&
868 !netif_is_l3_master(skb
->dev
) &&
869 !netif_is_l3_slave(skb
->dev
)) {
870 state
->okfn(state
->net
, state
->sk
, skb
);
877 /* This is called when br_netfilter has called into iptables/netfilter,
878 * and DNAT has taken place on a bridge-forwarded packet.
880 * neigh->output has created a new MAC header, with local br0 MAC
883 * This restores the original MAC saddr of the bridged packet
884 * before invoking bridge forward logic to transmit the packet.
886 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff
*skb
)
888 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
890 skb_pull(skb
, ETH_HLEN
);
891 nf_bridge
->bridged_dnat
= 0;
893 BUILD_BUG_ON(sizeof(nf_bridge
->neigh_header
) != (ETH_HLEN
- ETH_ALEN
));
895 skb_copy_to_linear_data_offset(skb
, -(ETH_HLEN
- ETH_ALEN
),
896 nf_bridge
->neigh_header
,
897 ETH_HLEN
- ETH_ALEN
);
898 skb
->dev
= nf_bridge
->physindev
;
900 nf_bridge
->physoutdev
= NULL
;
901 br_handle_frame_finish(dev_net(skb
->dev
), NULL
, skb
);
904 static int br_nf_dev_xmit(struct sk_buff
*skb
)
906 const struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
908 if (nf_bridge
&& nf_bridge
->bridged_dnat
) {
909 br_nf_pre_routing_finish_bridge_slow(skb
);
915 static const struct nf_br_ops br_ops
= {
916 .br_dev_xmit_hook
= br_nf_dev_xmit
,
919 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
920 * br_dev_queue_push_xmit is called afterwards */
921 static const struct nf_hook_ops br_nf_ops
[] = {
923 .hook
= br_nf_pre_routing
,
924 .pf
= NFPROTO_BRIDGE
,
925 .hooknum
= NF_BR_PRE_ROUTING
,
926 .priority
= NF_BR_PRI_BRNF
,
929 .hook
= br_nf_forward_ip
,
930 .pf
= NFPROTO_BRIDGE
,
931 .hooknum
= NF_BR_FORWARD
,
932 .priority
= NF_BR_PRI_BRNF
- 1,
935 .hook
= br_nf_forward_arp
,
936 .pf
= NFPROTO_BRIDGE
,
937 .hooknum
= NF_BR_FORWARD
,
938 .priority
= NF_BR_PRI_BRNF
,
941 .hook
= br_nf_post_routing
,
942 .pf
= NFPROTO_BRIDGE
,
943 .hooknum
= NF_BR_POST_ROUTING
,
944 .priority
= NF_BR_PRI_LAST
,
947 .hook
= ip_sabotage_in
,
949 .hooknum
= NF_INET_PRE_ROUTING
,
950 .priority
= NF_IP_PRI_FIRST
,
953 .hook
= ip_sabotage_in
,
955 .hooknum
= NF_INET_PRE_ROUTING
,
956 .priority
= NF_IP6_PRI_FIRST
,
960 static int brnf_device_event(struct notifier_block
*unused
, unsigned long event
,
963 struct net_device
*dev
= netdev_notifier_info_to_dev(ptr
);
964 struct brnf_net
*brnet
;
968 if (event
!= NETDEV_REGISTER
|| !(dev
->priv_flags
& IFF_EBRIDGE
))
974 brnet
= net_generic(net
, brnf_net_id
);
978 ret
= nf_register_net_hooks(net
, br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
982 brnet
->enabled
= true;
986 static struct notifier_block brnf_notifier __read_mostly
= {
987 .notifier_call
= brnf_device_event
,
990 /* recursively invokes nf_hook_slow (again), skipping already-called
991 * hooks (< NF_BR_PRI_BRNF).
993 * Called with rcu read lock held.
995 int br_nf_hook_thresh(unsigned int hook
, struct net
*net
,
996 struct sock
*sk
, struct sk_buff
*skb
,
997 struct net_device
*indev
,
998 struct net_device
*outdev
,
999 int (*okfn
)(struct net
*, struct sock
*,
1002 const struct nf_hook_entries
*e
;
1003 struct nf_hook_state state
;
1004 struct nf_hook_ops
**ops
;
1008 e
= rcu_dereference(net
->nf
.hooks_bridge
[hook
]);
1010 return okfn(net
, sk
, skb
);
1012 ops
= nf_hook_entries_get_hook_ops(e
);
1013 for (i
= 0; i
< e
->num_hook_entries
&&
1014 ops
[i
]->priority
<= NF_BR_PRI_BRNF
; i
++)
1017 nf_hook_state_init(&state
, hook
, NFPROTO_BRIDGE
, indev
, outdev
,
1020 ret
= nf_hook_slow(skb
, &state
, e
, i
);
1022 ret
= okfn(net
, sk
, skb
);
1027 #ifdef CONFIG_SYSCTL
1029 int brnf_sysctl_call_tables(struct ctl_table
*ctl
, int write
,
1030 void *buffer
, size_t *lenp
, loff_t
*ppos
)
1034 ret
= proc_dointvec(ctl
, write
, buffer
, lenp
, ppos
);
1036 if (write
&& *(int *)(ctl
->data
))
1037 *(int *)(ctl
->data
) = 1;
1041 static struct ctl_table brnf_table
[] = {
1043 .procname
= "bridge-nf-call-arptables",
1044 .maxlen
= sizeof(int),
1046 .proc_handler
= brnf_sysctl_call_tables
,
1049 .procname
= "bridge-nf-call-iptables",
1050 .maxlen
= sizeof(int),
1052 .proc_handler
= brnf_sysctl_call_tables
,
1055 .procname
= "bridge-nf-call-ip6tables",
1056 .maxlen
= sizeof(int),
1058 .proc_handler
= brnf_sysctl_call_tables
,
1061 .procname
= "bridge-nf-filter-vlan-tagged",
1062 .maxlen
= sizeof(int),
1064 .proc_handler
= brnf_sysctl_call_tables
,
1067 .procname
= "bridge-nf-filter-pppoe-tagged",
1068 .maxlen
= sizeof(int),
1070 .proc_handler
= brnf_sysctl_call_tables
,
1073 .procname
= "bridge-nf-pass-vlan-input-dev",
1074 .maxlen
= sizeof(int),
1076 .proc_handler
= brnf_sysctl_call_tables
,
1081 static inline void br_netfilter_sysctl_default(struct brnf_net
*brnf
)
1083 brnf
->call_iptables
= 1;
1084 brnf
->call_ip6tables
= 1;
1085 brnf
->call_arptables
= 1;
1086 brnf
->filter_vlan_tagged
= 0;
1087 brnf
->filter_pppoe_tagged
= 0;
1088 brnf
->pass_vlan_indev
= 0;
1091 static int br_netfilter_sysctl_init_net(struct net
*net
)
1093 struct ctl_table
*table
= brnf_table
;
1094 struct brnf_net
*brnet
;
1096 if (!net_eq(net
, &init_net
)) {
1097 table
= kmemdup(table
, sizeof(brnf_table
), GFP_KERNEL
);
1102 brnet
= net_generic(net
, brnf_net_id
);
1103 table
[0].data
= &brnet
->call_arptables
;
1104 table
[1].data
= &brnet
->call_iptables
;
1105 table
[2].data
= &brnet
->call_ip6tables
;
1106 table
[3].data
= &brnet
->filter_vlan_tagged
;
1107 table
[4].data
= &brnet
->filter_pppoe_tagged
;
1108 table
[5].data
= &brnet
->pass_vlan_indev
;
1110 br_netfilter_sysctl_default(brnet
);
1112 brnet
->ctl_hdr
= register_net_sysctl(net
, "net/bridge", table
);
1113 if (!brnet
->ctl_hdr
) {
1114 if (!net_eq(net
, &init_net
))
1123 static void br_netfilter_sysctl_exit_net(struct net
*net
,
1124 struct brnf_net
*brnet
)
1126 struct ctl_table
*table
= brnet
->ctl_hdr
->ctl_table_arg
;
1128 unregister_net_sysctl_table(brnet
->ctl_hdr
);
1129 if (!net_eq(net
, &init_net
))
1133 static int __net_init
brnf_init_net(struct net
*net
)
1135 return br_netfilter_sysctl_init_net(net
);
1139 static void __net_exit
brnf_exit_net(struct net
*net
)
1141 struct brnf_net
*brnet
;
1143 brnet
= net_generic(net
, brnf_net_id
);
1144 if (brnet
->enabled
) {
1145 nf_unregister_net_hooks(net
, br_nf_ops
, ARRAY_SIZE(br_nf_ops
));
1146 brnet
->enabled
= false;
1149 #ifdef CONFIG_SYSCTL
1150 br_netfilter_sysctl_exit_net(net
, brnet
);
1154 static struct pernet_operations brnf_net_ops __read_mostly
= {
1155 #ifdef CONFIG_SYSCTL
1156 .init
= brnf_init_net
,
1158 .exit
= brnf_exit_net
,
1160 .size
= sizeof(struct brnf_net
),
1163 static int __init
br_netfilter_init(void)
1167 ret
= register_pernet_subsys(&brnf_net_ops
);
1171 ret
= register_netdevice_notifier(&brnf_notifier
);
1173 unregister_pernet_subsys(&brnf_net_ops
);
1177 RCU_INIT_POINTER(nf_br_ops
, &br_ops
);
1178 printk(KERN_NOTICE
"Bridge firewalling registered\n");
1182 static void __exit
br_netfilter_fini(void)
1184 RCU_INIT_POINTER(nf_br_ops
, NULL
);
1185 unregister_netdevice_notifier(&brnf_notifier
);
1186 unregister_pernet_subsys(&brnf_net_ops
);
1189 module_init(br_netfilter_init
);
1190 module_exit(br_netfilter_fini
);
1192 MODULE_LICENSE("GPL");
1193 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1194 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1195 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");