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 = skb_ip_totlen(skb);
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) {
388 skb_dst_set(skb, &rt->dst);
397 if (skb_dst(skb)->dev == dev) {
399 skb->dev = nf_bridge->physindev;
400 nf_bridge_update_protocol(skb);
401 nf_bridge_push_encap_header(skb);
402 br_nf_hook_thresh(NF_BR_PRE_ROUTING,
403 net, sk, skb, skb->dev,
405 br_nf_pre_routing_finish_bridge);
408 ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
409 skb->pkt_type = PACKET_HOST;
412 rt = bridge_parent_rtable(nf_bridge->physindev);
418 skb_dst_set_noref(skb, &rt->dst);
421 skb->dev = nf_bridge->physindev;
422 nf_bridge_update_protocol(skb);
423 nf_bridge_push_encap_header(skb);
424 br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
425 br_handle_frame_finish);
429 static struct net_device *brnf_get_logical_dev(struct sk_buff *skb,
430 const struct net_device *dev,
431 const struct net *net)
433 struct net_device *vlan, *br;
434 struct brnf_net *brnet = net_generic(net, brnf_net_id);
436 br = bridge_parent(dev);
438 if (brnet->pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
441 vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
442 skb_vlan_tag_get(skb) & VLAN_VID_MASK);
444 return vlan ? vlan : br;
447 /* Some common code for IPv4/IPv6 */
448 struct net_device *setup_pre_routing(struct sk_buff *skb, const struct net *net)
450 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
452 if (skb->pkt_type == PACKET_OTHERHOST) {
453 skb->pkt_type = PACKET_HOST;
454 nf_bridge->pkt_otherhost = true;
457 nf_bridge->in_prerouting = 1;
458 nf_bridge->physindev = skb->dev;
459 skb->dev = brnf_get_logical_dev(skb, skb->dev, net);
461 if (skb->protocol == htons(ETH_P_8021Q))
462 nf_bridge->orig_proto = BRNF_PROTO_8021Q;
463 else if (skb->protocol == htons(ETH_P_PPP_SES))
464 nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
466 /* Must drop socket now because of tproxy. */
471 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
472 * Replicate the checks that IPv4 does on packet reception.
473 * Set skb->dev to the bridge device (i.e. parent of the
474 * receiving device) to make netfilter happy, the REDIRECT
475 * target in particular. Save the original destination IP
476 * address to be able to detect DNAT afterwards. */
477 static unsigned int br_nf_pre_routing(void *priv,
479 const struct nf_hook_state *state)
481 struct nf_bridge_info *nf_bridge;
482 struct net_bridge_port *p;
483 struct net_bridge *br;
484 __u32 len = nf_bridge_encap_header_len(skb);
485 struct brnf_net *brnet;
487 if (unlikely(!pskb_may_pull(skb, len)))
490 p = br_port_get_rcu(state->in);
495 brnet = net_generic(state->net, brnf_net_id);
496 if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
497 is_pppoe_ipv6(skb, state->net)) {
498 if (!brnet->call_ip6tables &&
499 !br_opt_get(br, BROPT_NF_CALL_IP6TABLES))
501 if (!ipv6_mod_enabled()) {
502 pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
506 nf_bridge_pull_encap_header_rcsum(skb);
507 return br_nf_pre_routing_ipv6(priv, skb, state);
510 if (!brnet->call_iptables && !br_opt_get(br, BROPT_NF_CALL_IPTABLES))
513 if (!IS_IP(skb) && !is_vlan_ip(skb, state->net) &&
514 !is_pppoe_ip(skb, state->net))
517 nf_bridge_pull_encap_header_rcsum(skb);
519 if (br_validate_ipv4(state->net, skb))
522 if (!nf_bridge_alloc(skb))
524 if (!setup_pre_routing(skb, state->net))
527 nf_bridge = nf_bridge_info_get(skb);
528 nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
530 skb->protocol = htons(ETH_P_IP);
531 skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
533 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
535 br_nf_pre_routing_finish);
541 /* PF_BRIDGE/FORWARD *************************************************/
542 static int br_nf_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
544 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
545 struct net_device *in;
547 if (!IS_ARP(skb) && !is_vlan_arp(skb, net)) {
549 if (skb->protocol == htons(ETH_P_IP))
550 nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
552 if (skb->protocol == htons(ETH_P_IPV6))
553 nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
555 in = nf_bridge->physindev;
556 if (nf_bridge->pkt_otherhost) {
557 skb->pkt_type = PACKET_OTHERHOST;
558 nf_bridge->pkt_otherhost = false;
560 nf_bridge_update_protocol(skb);
562 in = *((struct net_device **)(skb->cb));
564 nf_bridge_push_encap_header(skb);
566 br_nf_hook_thresh(NF_BR_FORWARD, net, sk, skb, in, skb->dev,
572 /* This is the 'purely bridged' case. For IP, we pass the packet to
573 * netfilter with indev and outdev set to the bridge device,
574 * but we are still able to filter on the 'real' indev/outdev
575 * because of the physdev module. For ARP, indev and outdev are the
577 static unsigned int br_nf_forward_ip(void *priv,
579 const struct nf_hook_state *state)
581 struct nf_bridge_info *nf_bridge;
582 struct net_device *parent;
585 nf_bridge = nf_bridge_info_get(skb);
589 /* Need exclusive nf_bridge_info since we might have multiple
590 * different physoutdevs. */
591 if (!nf_bridge_unshare(skb))
594 nf_bridge = nf_bridge_info_get(skb);
598 parent = bridge_parent(state->out);
602 if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
603 is_pppoe_ip(skb, state->net))
605 else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
606 is_pppoe_ipv6(skb, state->net))
611 nf_bridge_pull_encap_header(skb);
613 if (skb->pkt_type == PACKET_OTHERHOST) {
614 skb->pkt_type = PACKET_HOST;
615 nf_bridge->pkt_otherhost = true;
618 if (pf == NFPROTO_IPV4) {
619 if (br_validate_ipv4(state->net, skb))
621 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
624 if (pf == NFPROTO_IPV6) {
625 if (br_validate_ipv6(state->net, skb))
627 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
630 nf_bridge->physoutdev = skb->dev;
631 if (pf == NFPROTO_IPV4)
632 skb->protocol = htons(ETH_P_IP);
634 skb->protocol = htons(ETH_P_IPV6);
636 NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
637 brnf_get_logical_dev(skb, state->in, state->net),
638 parent, br_nf_forward_finish);
643 static unsigned int br_nf_forward_arp(void *priv,
645 const struct nf_hook_state *state)
647 struct net_bridge_port *p;
648 struct net_bridge *br;
649 struct net_device **d = (struct net_device **)(skb->cb);
650 struct brnf_net *brnet;
652 p = br_port_get_rcu(state->out);
657 brnet = net_generic(state->net, brnf_net_id);
658 if (!brnet->call_arptables && !br_opt_get(br, BROPT_NF_CALL_ARPTABLES))
662 if (!is_vlan_arp(skb, state->net))
664 nf_bridge_pull_encap_header(skb);
667 if (unlikely(!pskb_may_pull(skb, sizeof(struct arphdr))))
670 if (arp_hdr(skb)->ar_pln != 4) {
671 if (is_vlan_arp(skb, state->net))
672 nf_bridge_push_encap_header(skb);
676 NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
677 state->in, state->out, br_nf_forward_finish);
682 static int br_nf_push_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
684 struct brnf_frag_data *data;
687 data = this_cpu_ptr(&brnf_frag_data_storage);
688 err = skb_cow_head(skb, data->size);
695 if (data->vlan_proto)
696 __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci);
698 skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
699 __skb_push(skb, data->encap_size);
701 nf_bridge_info_free(skb);
702 return br_dev_queue_push_xmit(net, sk, skb);
706 br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
707 int (*output)(struct net *, struct sock *, struct sk_buff *))
709 unsigned int mtu = ip_skb_dst_mtu(sk, skb);
710 struct iphdr *iph = ip_hdr(skb);
712 if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
713 (IPCB(skb)->frag_max_size &&
714 IPCB(skb)->frag_max_size > mtu))) {
715 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
720 return ip_do_fragment(net, sk, skb, output);
723 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
725 const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
727 if (nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
728 return PPPOE_SES_HLEN;
732 static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
734 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
735 unsigned int mtu, mtu_reserved;
737 mtu_reserved = nf_bridge_mtu_reduction(skb);
740 if (nf_bridge->pkt_otherhost) {
741 skb->pkt_type = PACKET_OTHERHOST;
742 nf_bridge->pkt_otherhost = false;
745 if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
746 mtu = nf_bridge->frag_max_size;
748 nf_bridge_update_protocol(skb);
749 nf_bridge_push_encap_header(skb);
751 if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
752 nf_bridge_info_free(skb);
753 return br_dev_queue_push_xmit(net, sk, skb);
756 /* This is wrong! We should preserve the original fragment
757 * boundaries by preserving frag_list rather than refragmenting.
759 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) &&
760 skb->protocol == htons(ETH_P_IP)) {
761 struct brnf_frag_data *data;
763 if (br_validate_ipv4(net, skb))
766 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
768 data = this_cpu_ptr(&brnf_frag_data_storage);
770 if (skb_vlan_tag_present(skb)) {
771 data->vlan_tci = skb->vlan_tci;
772 data->vlan_proto = skb->vlan_proto;
774 data->vlan_proto = 0;
777 data->encap_size = nf_bridge_encap_header_len(skb);
778 data->size = ETH_HLEN + data->encap_size;
780 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
783 return br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit);
785 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) &&
786 skb->protocol == htons(ETH_P_IPV6)) {
787 const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
788 struct brnf_frag_data *data;
790 if (br_validate_ipv6(net, skb))
793 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
795 data = this_cpu_ptr(&brnf_frag_data_storage);
796 data->encap_size = nf_bridge_encap_header_len(skb);
797 data->size = ETH_HLEN + data->encap_size;
799 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
803 return v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit);
808 nf_bridge_info_free(skb);
809 return br_dev_queue_push_xmit(net, sk, skb);
815 /* PF_BRIDGE/POST_ROUTING ********************************************/
816 static unsigned int br_nf_post_routing(void *priv,
818 const struct nf_hook_state *state)
820 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
821 struct net_device *realoutdev = bridge_parent(skb->dev);
824 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
825 * on a bridge, but was delivered locally and is now being routed:
827 * POST_ROUTING was already invoked from the ip stack.
829 if (!nf_bridge || !nf_bridge->physoutdev)
835 if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
836 is_pppoe_ip(skb, state->net))
838 else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
839 is_pppoe_ipv6(skb, state->net))
844 if (skb->pkt_type == PACKET_OTHERHOST) {
845 skb->pkt_type = PACKET_HOST;
846 nf_bridge->pkt_otherhost = true;
849 nf_bridge_pull_encap_header(skb);
850 if (pf == NFPROTO_IPV4)
851 skb->protocol = htons(ETH_P_IP);
853 skb->protocol = htons(ETH_P_IPV6);
855 NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
857 br_nf_dev_queue_xmit);
862 /* IP/SABOTAGE *****************************************************/
863 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
864 * for the second time. */
865 static unsigned int ip_sabotage_in(void *priv,
867 const struct nf_hook_state *state)
869 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
871 if (nf_bridge && !nf_bridge->in_prerouting &&
872 !netif_is_l3_master(skb->dev) &&
873 !netif_is_l3_slave(skb->dev)) {
874 nf_bridge_info_free(skb);
875 state->okfn(state->net, state->sk, skb);
882 /* This is called when br_netfilter has called into iptables/netfilter,
883 * and DNAT has taken place on a bridge-forwarded packet.
885 * neigh->output has created a new MAC header, with local br0 MAC
888 * This restores the original MAC saddr of the bridged packet
889 * before invoking bridge forward logic to transmit the packet.
891 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
893 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
895 skb_pull(skb, ETH_HLEN);
896 nf_bridge->bridged_dnat = 0;
898 BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
900 skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
901 nf_bridge->neigh_header,
902 ETH_HLEN - ETH_ALEN);
903 skb->dev = nf_bridge->physindev;
905 nf_bridge->physoutdev = NULL;
906 br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
909 static int br_nf_dev_xmit(struct sk_buff *skb)
911 const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
913 if (nf_bridge && nf_bridge->bridged_dnat) {
914 br_nf_pre_routing_finish_bridge_slow(skb);
920 static const struct nf_br_ops br_ops = {
921 .br_dev_xmit_hook = br_nf_dev_xmit,
924 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
925 * br_dev_queue_push_xmit is called afterwards */
926 static const struct nf_hook_ops br_nf_ops[] = {
928 .hook = br_nf_pre_routing,
929 .pf = NFPROTO_BRIDGE,
930 .hooknum = NF_BR_PRE_ROUTING,
931 .priority = NF_BR_PRI_BRNF,
934 .hook = br_nf_forward_ip,
935 .pf = NFPROTO_BRIDGE,
936 .hooknum = NF_BR_FORWARD,
937 .priority = NF_BR_PRI_BRNF - 1,
940 .hook = br_nf_forward_arp,
941 .pf = NFPROTO_BRIDGE,
942 .hooknum = NF_BR_FORWARD,
943 .priority = NF_BR_PRI_BRNF,
946 .hook = br_nf_post_routing,
947 .pf = NFPROTO_BRIDGE,
948 .hooknum = NF_BR_POST_ROUTING,
949 .priority = NF_BR_PRI_LAST,
952 .hook = ip_sabotage_in,
954 .hooknum = NF_INET_PRE_ROUTING,
955 .priority = NF_IP_PRI_FIRST,
958 .hook = ip_sabotage_in,
960 .hooknum = NF_INET_PRE_ROUTING,
961 .priority = NF_IP6_PRI_FIRST,
965 static int brnf_device_event(struct notifier_block *unused, unsigned long event,
968 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
969 struct brnf_net *brnet;
973 if (event != NETDEV_REGISTER || !netif_is_bridge_master(dev))
979 brnet = net_generic(net, brnf_net_id);
983 ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
987 brnet->enabled = true;
991 static struct notifier_block brnf_notifier __read_mostly = {
992 .notifier_call = brnf_device_event,
995 /* recursively invokes nf_hook_slow (again), skipping already-called
996 * hooks (< NF_BR_PRI_BRNF).
998 * Called with rcu read lock held.
1000 int br_nf_hook_thresh(unsigned int hook, struct net *net,
1001 struct sock *sk, struct sk_buff *skb,
1002 struct net_device *indev,
1003 struct net_device *outdev,
1004 int (*okfn)(struct net *, struct sock *,
1007 const struct nf_hook_entries *e;
1008 struct nf_hook_state state;
1009 struct nf_hook_ops **ops;
1013 e = rcu_dereference(net->nf.hooks_bridge[hook]);
1015 return okfn(net, sk, skb);
1017 ops = nf_hook_entries_get_hook_ops(e);
1018 for (i = 0; i < e->num_hook_entries; i++) {
1019 /* These hooks have already been called */
1020 if (ops[i]->priority < NF_BR_PRI_BRNF)
1023 /* These hooks have not been called yet, run them. */
1024 if (ops[i]->priority > NF_BR_PRI_BRNF)
1027 /* take a closer look at NF_BR_PRI_BRNF. */
1028 if (ops[i]->hook == br_nf_pre_routing) {
1029 /* This hook diverted the skb to this function,
1030 * hooks after this have not been run yet.
1037 nf_hook_state_init(&state, hook, NFPROTO_BRIDGE, indev, outdev,
1040 ret = nf_hook_slow(skb, &state, e, i);
1042 ret = okfn(net, sk, skb);
1047 #ifdef CONFIG_SYSCTL
1049 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
1050 void *buffer, size_t *lenp, loff_t *ppos)
1054 ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1056 if (write && *(int *)(ctl->data))
1057 *(int *)(ctl->data) = 1;
1061 static struct ctl_table brnf_table[] = {
1063 .procname = "bridge-nf-call-arptables",
1064 .maxlen = sizeof(int),
1066 .proc_handler = brnf_sysctl_call_tables,
1069 .procname = "bridge-nf-call-iptables",
1070 .maxlen = sizeof(int),
1072 .proc_handler = brnf_sysctl_call_tables,
1075 .procname = "bridge-nf-call-ip6tables",
1076 .maxlen = sizeof(int),
1078 .proc_handler = brnf_sysctl_call_tables,
1081 .procname = "bridge-nf-filter-vlan-tagged",
1082 .maxlen = sizeof(int),
1084 .proc_handler = brnf_sysctl_call_tables,
1087 .procname = "bridge-nf-filter-pppoe-tagged",
1088 .maxlen = sizeof(int),
1090 .proc_handler = brnf_sysctl_call_tables,
1093 .procname = "bridge-nf-pass-vlan-input-dev",
1094 .maxlen = sizeof(int),
1096 .proc_handler = brnf_sysctl_call_tables,
1101 static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
1103 brnf->call_iptables = 1;
1104 brnf->call_ip6tables = 1;
1105 brnf->call_arptables = 1;
1106 brnf->filter_vlan_tagged = 0;
1107 brnf->filter_pppoe_tagged = 0;
1108 brnf->pass_vlan_indev = 0;
1111 static int br_netfilter_sysctl_init_net(struct net *net)
1113 struct ctl_table *table = brnf_table;
1114 struct brnf_net *brnet;
1116 if (!net_eq(net, &init_net)) {
1117 table = kmemdup(table, sizeof(brnf_table), GFP_KERNEL);
1122 brnet = net_generic(net, brnf_net_id);
1123 table[0].data = &brnet->call_arptables;
1124 table[1].data = &brnet->call_iptables;
1125 table[2].data = &brnet->call_ip6tables;
1126 table[3].data = &brnet->filter_vlan_tagged;
1127 table[4].data = &brnet->filter_pppoe_tagged;
1128 table[5].data = &brnet->pass_vlan_indev;
1130 br_netfilter_sysctl_default(brnet);
1132 brnet->ctl_hdr = register_net_sysctl(net, "net/bridge", table);
1133 if (!brnet->ctl_hdr) {
1134 if (!net_eq(net, &init_net))
1143 static void br_netfilter_sysctl_exit_net(struct net *net,
1144 struct brnf_net *brnet)
1146 struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
1148 unregister_net_sysctl_table(brnet->ctl_hdr);
1149 if (!net_eq(net, &init_net))
1153 static int __net_init brnf_init_net(struct net *net)
1155 return br_netfilter_sysctl_init_net(net);
1159 static void __net_exit brnf_exit_net(struct net *net)
1161 struct brnf_net *brnet;
1163 brnet = net_generic(net, brnf_net_id);
1164 if (brnet->enabled) {
1165 nf_unregister_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1166 brnet->enabled = false;
1169 #ifdef CONFIG_SYSCTL
1170 br_netfilter_sysctl_exit_net(net, brnet);
1174 static struct pernet_operations brnf_net_ops __read_mostly = {
1175 #ifdef CONFIG_SYSCTL
1176 .init = brnf_init_net,
1178 .exit = brnf_exit_net,
1180 .size = sizeof(struct brnf_net),
1183 static int __init br_netfilter_init(void)
1187 ret = register_pernet_subsys(&brnf_net_ops);
1191 ret = register_netdevice_notifier(&brnf_notifier);
1193 unregister_pernet_subsys(&brnf_net_ops);
1197 RCU_INIT_POINTER(nf_br_ops, &br_ops);
1198 printk(KERN_NOTICE "Bridge firewalling registered\n");
1202 static void __exit br_netfilter_fini(void)
1204 RCU_INIT_POINTER(nf_br_ops, NULL);
1205 unregister_netdevice_notifier(&brnf_notifier);
1206 unregister_pernet_subsys(&brnf_net_ops);
1209 module_init(br_netfilter_init);
1210 module_exit(br_netfilter_fini);
1212 MODULE_LICENSE("GPL");
1213 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1214 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1215 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");