net/bridge/br_netfilter_hooks.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Handle firewalling
   4  *      Linux ethernet bridge
   5  *
   6  *      Authors:
   7  *      Lennert Buytenhek               <buytenh@gnu.org>
   8  *      Bart De Schuymer                <bdschuym@pandora.be>
   9  *
  10  *      Lennert dedicates this file to Kerstin Wurdinger.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/ip.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>
  32
  33 #include <net/ip.h>
  34 #include <net/ipv6.h>
  35 #include <net/addrconf.h>
  36 #include <net/route.h>
  37 #include <net/netfilter/br_netfilter.h>
  38 #include <net/netns/generic.h>
  39
  40 #include <linux/uaccess.h>
  41 #include "br_private.h"
  42 #ifdef CONFIG_SYSCTL
  43 #include <linux/sysctl.h>
  44 #endif
  45
  46 static unsigned int brnf_net_id __read_mostly;
  47
  48 struct brnf_net {
  49         bool enabled;
  50
  51 #ifdef CONFIG_SYSCTL
  52         struct ctl_table_header *ctl_hdr;
  53 #endif
  54
  55         /* default value is 1 */
  56         int call_iptables;
  57         int call_ip6tables;
  58         int call_arptables;
  59
  60         /* default value is 0 */
  61         int filter_vlan_tagged;
  62         int filter_pppoe_tagged;
  63         int pass_vlan_indev;
  64 };
  65
  66 #define IS_IP(skb) \
  67         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
  68
  69 #define IS_IPV6(skb) \
  70         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
  71
  72 #define IS_ARP(skb) \
  73         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
  74
  75 static inline __be16 vlan_proto(const struct sk_buff *skb)
  76 {
  77         if (skb_vlan_tag_present(skb))
  78                 return skb->protocol;
  79         else if (skb->protocol == htons(ETH_P_8021Q))
  80                 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
  81         else
  82                 return 0;
  83 }
  84
  85 static inline bool is_vlan_ip(const struct sk_buff *skb, const struct net *net)
  86 {
  87         struct brnf_net *brnet = net_generic(net, brnf_net_id);
  88
  89         return vlan_proto(skb) == htons(ETH_P_IP) && brnet->filter_vlan_tagged;
  90 }
  91
  92 static inline bool is_vlan_ipv6(const struct sk_buff *skb,
  93                                 const struct net *net)
  94 {
  95         struct brnf_net *brnet = net_generic(net, brnf_net_id);
  96
  97         return vlan_proto(skb) == htons(ETH_P_IPV6) &&
  98                brnet->filter_vlan_tagged;
  99 }
 100
 101 static inline bool is_vlan_arp(const struct sk_buff *skb, const struct net *net)
 102 {
 103         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 104
 105         return vlan_proto(skb) == htons(ETH_P_ARP) && brnet->filter_vlan_tagged;
 106 }
 107
 108 static inline __be16 pppoe_proto(const struct sk_buff *skb)
 109 {
 110         return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
 111                             sizeof(struct pppoe_hdr)));
 112 }
 113
 114 static inline bool is_pppoe_ip(const struct sk_buff *skb, const struct net *net)
 115 {
 116         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 117
 118         return skb->protocol == htons(ETH_P_PPP_SES) &&
 119                pppoe_proto(skb) == htons(PPP_IP) && brnet->filter_pppoe_tagged;
 120 }
 121
 122 static inline bool is_pppoe_ipv6(const struct sk_buff *skb,
 123                                  const struct net *net)
 124 {
 125         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 126
 127         return skb->protocol == htons(ETH_P_PPP_SES) &&
 128                pppoe_proto(skb) == htons(PPP_IPV6) &&
 129                brnet->filter_pppoe_tagged;
 130 }
 131
 132 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
 133 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
 134
 135 struct brnf_frag_data {
 136         char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
 137         u8 encap_size;
 138         u8 size;
 139         u16 vlan_tci;
 140         __be16 vlan_proto;
 141 };
 142
 143 static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage);
 144
 145 static void nf_bridge_info_free(struct sk_buff *skb)
 146 {
 147         skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
 148 }
 149
 150 static inline struct net_device *bridge_parent(const struct net_device *dev)
 151 {
 152         struct net_bridge_port *port;
 153
 154         port = br_port_get_rcu(dev);
 155         return port ? port->br->dev : NULL;
 156 }
 157
 158 static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
 159 {
 160         return skb_ext_add(skb, SKB_EXT_BRIDGE_NF);
 161 }
 162
 163 unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
 164 {
 165         switch (skb->protocol) {
 166         case __cpu_to_be16(ETH_P_8021Q):
 167                 return VLAN_HLEN;
 168         case __cpu_to_be16(ETH_P_PPP_SES):
 169                 return PPPOE_SES_HLEN;
 170         default:
 171                 return 0;
 172         }
 173 }
 174
 175 static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
 176 {
 177         unsigned int len = nf_bridge_encap_header_len(skb);
 178
 179         skb_pull(skb, len);
 180         skb->network_header += len;
 181 }
 182
 183 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
 184 {
 185         unsigned int len = nf_bridge_encap_header_len(skb);
 186
 187         skb_pull_rcsum(skb, len);
 188         skb->network_header += len;
 189 }
 190
 191 /* When handing a packet over to the IP layer
 192  * check whether we have a skb that is in the
 193  * expected format
 194  */
 195
 196 static int br_validate_ipv4(struct net *net, struct sk_buff *skb)
 197 {
 198         const struct iphdr *iph;
 199         u32 len;
 200
 201         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 202                 goto inhdr_error;
 203
 204         iph = ip_hdr(skb);
 205
 206         /* Basic sanity checks */
 207         if (iph->ihl < 5 || iph->version != 4)
 208                 goto inhdr_error;
 209
 210         if (!pskb_may_pull(skb, iph->ihl*4))
 211                 goto inhdr_error;
 212
 213         iph = ip_hdr(skb);
 214         if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
 215                 goto csum_error;
 216
 217         len = skb_ip_totlen(skb);
 218         if (skb->len < len) {
 219                 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
 220                 goto drop;
 221         } else if (len < (iph->ihl*4))
 222                 goto inhdr_error;
 223
 224         if (pskb_trim_rcsum(skb, len)) {
 225                 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
 226                 goto drop;
 227         }
 228
 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
 233          * we're lazy!
 234          */
 235         return 0;
 236
 237 csum_error:
 238         __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
 239 inhdr_error:
 240         __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
 241 drop:
 242         return -1;
 243 }
 244
 245 void nf_bridge_update_protocol(struct sk_buff *skb)
 246 {
 247         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 248
 249         switch (nf_bridge->orig_proto) {
 250         case BRNF_PROTO_8021Q:
 251                 skb->protocol = htons(ETH_P_8021Q);
 252                 break;
 253         case BRNF_PROTO_PPPOE:
 254                 skb->protocol = htons(ETH_P_PPP_SES);
 255                 break;
 256         case BRNF_PROTO_UNCHANGED:
 257                 break;
 258         }
 259 }
 260
 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.
 265  */
 266 int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_buff *skb)
 267 {
 268         struct neighbour *neigh;
 269         struct dst_entry *dst;
 270
 271         skb->dev = bridge_parent(skb->dev);
 272         if (!skb->dev)
 273                 goto free_skb;
 274         dst = skb_dst(skb);
 275         neigh = dst_neigh_lookup_skb(dst, skb);
 276         if (neigh) {
 277                 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 278                 int ret;
 279
 280                 if ((READ_ONCE(neigh->nud_state) & NUD_CONNECTED) &&
 281                     READ_ONCE(neigh->hh.hh_len)) {
 282                         struct net_device *br_indev;
 283
 284                         br_indev = nf_bridge_get_physindev(skb, net);
 285                         if (!br_indev) {
 286                                 neigh_release(neigh);
 287                                 goto free_skb;
 288                         }
 289
 290                         neigh_hh_bridge(&neigh->hh, skb);
 291                         skb->dev = br_indev;
 292
 293                         ret = br_handle_frame_finish(net, sk, skb);
 294                 } else {
 295                         /* the neighbour function below overwrites the complete
 296                          * MAC header, so we save the Ethernet source address and
 297                          * protocol number.
 298                          */
 299                         skb_copy_from_linear_data_offset(skb,
 300                                                          -(ETH_HLEN-ETH_ALEN),
 301                                                          nf_bridge->neigh_header,
 302                                                          ETH_HLEN-ETH_ALEN);
 303                         /* tell br_dev_xmit to continue with forwarding */
 304                         nf_bridge->bridged_dnat = 1;
 305                         /* FIXME Need to refragment */
 306                         ret = READ_ONCE(neigh->output)(neigh, skb);
 307                 }
 308                 neigh_release(neigh);
 309                 return ret;
 310         }
 311 free_skb:
 312         kfree_skb(skb);
 313         return 0;
 314 }
 315
 316 static inline bool
 317 br_nf_ipv4_daddr_was_changed(const struct sk_buff *skb,
 318                              const struct nf_bridge_info *nf_bridge)
 319 {
 320         return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr;
 321 }
 322
 323 /* This requires some explaining. If DNAT has taken place,
 324  * we will need to fix up the destination Ethernet address.
 325  * This is also true when SNAT takes place (for the reply direction).
 326  *
 327  * There are two cases to consider:
 328  * 1. The packet was DNAT'ed to a device in the same bridge
 329  *    port group as it was received on. We can still bridge
 330  *    the packet.
 331  * 2. The packet was DNAT'ed to a different device, either
 332  *    a non-bridged device or another bridge port group.
 333  *    The packet will need to be routed.
 334  *
 335  * The correct way of distinguishing between these two cases is to
 336  * call ip_route_input() and to look at skb->dst->dev, which is
 337  * changed to the destination device if ip_route_input() succeeds.
 338  *
 339  * Let's first consider the case that ip_route_input() succeeds:
 340  *
 341  * If the output device equals the logical bridge device the packet
 342  * came in on, we can consider this bridging. The corresponding MAC
 343  * address will be obtained in br_nf_pre_routing_finish_bridge.
 344  * Otherwise, the packet is considered to be routed and we just
 345  * change the destination MAC address so that the packet will
 346  * later be passed up to the IP stack to be routed. For a redirected
 347  * packet, ip_route_input() will give back the localhost as output device,
 348  * which differs from the bridge device.
 349  *
 350  * Let's now consider the case that ip_route_input() fails:
 351  *
 352  * This can be because the destination address is martian, in which case
 353  * the packet will be dropped.
 354  * If IP forwarding is disabled, ip_route_input() will fail, while
 355  * ip_route_output_key() can return success. The source
 356  * address for ip_route_output_key() is set to zero, so ip_route_output_key()
 357  * thinks we're handling a locally generated packet and won't care
 358  * if IP forwarding is enabled. If the output device equals the logical bridge
 359  * device, we proceed as if ip_route_input() succeeded. If it differs from the
 360  * logical bridge port or if ip_route_output_key() fails we drop the packet.
 361  */
 362 static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 363 {
 364         struct net_device *dev = skb->dev, *br_indev;
 365         struct iphdr *iph = ip_hdr(skb);
 366         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 367         struct rtable *rt;
 368         int err;
 369
 370         br_indev = nf_bridge_get_physindev(skb, net);
 371         if (!br_indev) {
 372                 kfree_skb(skb);
 373                 return 0;
 374         }
 375
 376         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 377
 378         if (nf_bridge->pkt_otherhost) {
 379                 skb->pkt_type = PACKET_OTHERHOST;
 380                 nf_bridge->pkt_otherhost = false;
 381         }
 382         nf_bridge->in_prerouting = 0;
 383         if (br_nf_ipv4_daddr_was_changed(skb, nf_bridge)) {
 384                 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
 385                         struct in_device *in_dev = __in_dev_get_rcu(dev);
 386
 387                         /* If err equals -EHOSTUNREACH the error is due to a
 388                          * martian destination or due to the fact that
 389                          * forwarding is disabled. For most martian packets,
 390                          * ip_route_output_key() will fail. It won't fail for 2 types of
 391                          * martian destinations: loopback destinations and destination
 392                          * 0.0.0.0. In both cases the packet will be dropped because the
 393                          * destination is the loopback device and not the bridge. */
 394                         if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
 395                                 goto free_skb;
 396
 397                         rt = ip_route_output(net, iph->daddr, 0,
 398                                              RT_TOS(iph->tos), 0);
 399                         if (!IS_ERR(rt)) {
 400                                 /* - Bridged-and-DNAT'ed traffic doesn't
 401                                  *   require ip_forwarding. */
 402                                 if (rt->dst.dev == dev) {
 403                                         skb_dst_drop(skb);
 404                                         skb_dst_set(skb, &rt->dst);
 405                                         goto bridged_dnat;
 406                                 }
 407                                 ip_rt_put(rt);
 408                         }
 409 free_skb:
 410                         kfree_skb(skb);
 411                         return 0;
 412                 } else {
 413                         if (skb_dst(skb)->dev == dev) {
 414 bridged_dnat:
 415                                 skb->dev = br_indev;
 416                                 nf_bridge_update_protocol(skb);
 417                                 nf_bridge_push_encap_header(skb);
 418                                 br_nf_hook_thresh(NF_BR_PRE_ROUTING,
 419                                                   net, sk, skb, skb->dev,
 420                                                   NULL,
 421                                                   br_nf_pre_routing_finish_bridge);
 422                                 return 0;
 423                         }
 424                         ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
 425                         skb->pkt_type = PACKET_HOST;
 426                 }
 427         } else {
 428                 rt = bridge_parent_rtable(br_indev);
 429                 if (!rt) {
 430                         kfree_skb(skb);
 431                         return 0;
 432                 }
 433                 skb_dst_drop(skb);
 434                 skb_dst_set_noref(skb, &rt->dst);
 435         }
 436
 437         skb->dev = br_indev;
 438         nf_bridge_update_protocol(skb);
 439         nf_bridge_push_encap_header(skb);
 440         br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
 441                           br_handle_frame_finish);
 442         return 0;
 443 }
 444
 445 static struct net_device *brnf_get_logical_dev(struct sk_buff *skb,
 446                                                const struct net_device *dev,
 447                                                const struct net *net)
 448 {
 449         struct net_device *vlan, *br;
 450         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 451
 452         br = bridge_parent(dev);
 453
 454         if (brnet->pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
 455                 return br;
 456
 457         vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
 458                                     skb_vlan_tag_get(skb) & VLAN_VID_MASK);
 459
 460         return vlan ? vlan : br;
 461 }
 462
 463 /* Some common code for IPv4/IPv6 */
 464 struct net_device *setup_pre_routing(struct sk_buff *skb, const struct net *net)
 465 {
 466         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 467
 468         if (skb->pkt_type == PACKET_OTHERHOST) {
 469                 skb->pkt_type = PACKET_HOST;
 470                 nf_bridge->pkt_otherhost = true;
 471         }
 472
 473         nf_bridge->in_prerouting = 1;
 474         nf_bridge->physinif = skb->dev->ifindex;
 475         skb->dev = brnf_get_logical_dev(skb, skb->dev, net);
 476
 477         if (skb->protocol == htons(ETH_P_8021Q))
 478                 nf_bridge->orig_proto = BRNF_PROTO_8021Q;
 479         else if (skb->protocol == htons(ETH_P_PPP_SES))
 480                 nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
 481
 482         /* Must drop socket now because of tproxy. */
 483         skb_orphan(skb);
 484         return skb->dev;
 485 }
 486
 487 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
 488  * Replicate the checks that IPv4 does on packet reception.
 489  * Set skb->dev to the bridge device (i.e. parent of the
 490  * receiving device) to make netfilter happy, the REDIRECT
 491  * target in particular.  Save the original destination IP
 492  * address to be able to detect DNAT afterwards. */
 493 static unsigned int br_nf_pre_routing(void *priv,
 494                                       struct sk_buff *skb,
 495                                       const struct nf_hook_state *state)
 496 {
 497         struct nf_bridge_info *nf_bridge;
 498         struct net_bridge_port *p;
 499         struct net_bridge *br;
 500         __u32 len = nf_bridge_encap_header_len(skb);
 501         struct brnf_net *brnet;
 502
 503         if (unlikely(!pskb_may_pull(skb, len)))
 504                 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
 505
 506         p = br_port_get_rcu(state->in);
 507         if (p == NULL)
 508                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 509         br = p->br;
 510
 511         brnet = net_generic(state->net, brnf_net_id);
 512         if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 513             is_pppoe_ipv6(skb, state->net)) {
 514                 if (!brnet->call_ip6tables &&
 515                     !br_opt_get(br, BROPT_NF_CALL_IP6TABLES))
 516                         return NF_ACCEPT;
 517                 if (!ipv6_mod_enabled()) {
 518                         pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
 519                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IPV6DISABLED, 0);
 520                 }
 521
 522                 nf_bridge_pull_encap_header_rcsum(skb);
 523                 return br_nf_pre_routing_ipv6(priv, skb, state);
 524         }
 525
 526         if (!brnet->call_iptables && !br_opt_get(br, BROPT_NF_CALL_IPTABLES))
 527                 return NF_ACCEPT;
 528
 529         if (!IS_IP(skb) && !is_vlan_ip(skb, state->net) &&
 530             !is_pppoe_ip(skb, state->net))
 531                 return NF_ACCEPT;
 532
 533         nf_bridge_pull_encap_header_rcsum(skb);
 534
 535         if (br_validate_ipv4(state->net, skb))
 536                 return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 537
 538         if (!nf_bridge_alloc(skb))
 539                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 540         if (!setup_pre_routing(skb, state->net))
 541                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 542
 543         nf_bridge = nf_bridge_info_get(skb);
 544         nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
 545
 546         skb->protocol = htons(ETH_P_IP);
 547         skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
 548
 549         NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 550                 skb->dev, NULL,
 551                 br_nf_pre_routing_finish);
 552
 553         return NF_STOLEN;
 554 }
 555
 556
 557 /* PF_BRIDGE/FORWARD *************************************************/
 558 static int br_nf_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 559 {
 560         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 561         struct net_device *in;
 562
 563         if (!IS_ARP(skb) && !is_vlan_arp(skb, net)) {
 564
 565                 if (skb->protocol == htons(ETH_P_IP))
 566                         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 567
 568                 if (skb->protocol == htons(ETH_P_IPV6))
 569                         nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
 570
 571                 in = nf_bridge_get_physindev(skb, net);
 572                 if (!in) {
 573                         kfree_skb(skb);
 574                         return 0;
 575                 }
 576                 if (nf_bridge->pkt_otherhost) {
 577                         skb->pkt_type = PACKET_OTHERHOST;
 578                         nf_bridge->pkt_otherhost = false;
 579                 }
 580                 nf_bridge_update_protocol(skb);
 581         } else {
 582                 in = *((struct net_device **)(skb->cb));
 583         }
 584         nf_bridge_push_encap_header(skb);
 585
 586         br_nf_hook_thresh(NF_BR_FORWARD, net, sk, skb, in, skb->dev,
 587                           br_forward_finish);
 588         return 0;
 589 }
 590
 591
 592 static unsigned int br_nf_forward_ip(struct sk_buff *skb,
 593                                      const struct nf_hook_state *state,
 594                                      u8 pf)
 595 {
 596         struct nf_bridge_info *nf_bridge;
 597         struct net_device *parent;
 598
 599         nf_bridge = nf_bridge_info_get(skb);
 600         if (!nf_bridge)
 601                 return NF_ACCEPT;
 602
 603         /* Need exclusive nf_bridge_info since we might have multiple
 604          * different physoutdevs. */
 605         if (!nf_bridge_unshare(skb))
 606                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 607
 608         nf_bridge = nf_bridge_info_get(skb);
 609         if (!nf_bridge)
 610                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 611
 612         parent = bridge_parent(state->out);
 613         if (!parent)
 614                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 615
 616         nf_bridge_pull_encap_header(skb);
 617
 618         if (skb->pkt_type == PACKET_OTHERHOST) {
 619                 skb->pkt_type = PACKET_HOST;
 620                 nf_bridge->pkt_otherhost = true;
 621         }
 622
 623         if (pf == NFPROTO_IPV4) {
 624                 if (br_validate_ipv4(state->net, skb))
 625                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 626                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 627                 skb->protocol = htons(ETH_P_IP);
 628         } else if (pf == NFPROTO_IPV6) {
 629                 if (br_validate_ipv6(state->net, skb))
 630                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 631                 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
 632                 skb->protocol = htons(ETH_P_IPV6);
 633         } else {
 634                 WARN_ON_ONCE(1);
 635                 return NF_DROP;
 636         }
 637
 638         nf_bridge->physoutdev = skb->dev;
 639
 640         NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
 641                 brnf_get_logical_dev(skb, state->in, state->net),
 642                 parent, br_nf_forward_finish);
 643
 644         return NF_STOLEN;
 645 }
 646
 647 static unsigned int br_nf_forward_arp(struct sk_buff *skb,
 648                                       const struct nf_hook_state *state)
 649 {
 650         struct net_bridge_port *p;
 651         struct net_bridge *br;
 652         struct net_device **d = (struct net_device **)(skb->cb);
 653         struct brnf_net *brnet;
 654
 655         p = br_port_get_rcu(state->out);
 656         if (p == NULL)
 657                 return NF_ACCEPT;
 658         br = p->br;
 659
 660         brnet = net_generic(state->net, brnf_net_id);
 661         if (!brnet->call_arptables && !br_opt_get(br, BROPT_NF_CALL_ARPTABLES))
 662                 return NF_ACCEPT;
 663
 664         if (is_vlan_arp(skb, state->net))
 665                 nf_bridge_pull_encap_header(skb);
 666
 667         if (unlikely(!pskb_may_pull(skb, sizeof(struct arphdr))))
 668                 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
 669
 670         if (arp_hdr(skb)->ar_pln != 4) {
 671                 if (is_vlan_arp(skb, state->net))
 672                         nf_bridge_push_encap_header(skb);
 673                 return NF_ACCEPT;
 674         }
 675         *d = state->in;
 676         NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
 677                 state->in, state->out, br_nf_forward_finish);
 678
 679         return NF_STOLEN;
 680 }
 681
 682 /* This is the 'purely bridged' case.  For IP, we pass the packet to
 683  * netfilter with indev and outdev set to the bridge device,
 684  * but we are still able to filter on the 'real' indev/outdev
 685  * because of the physdev module. For ARP, indev and outdev are the
 686  * bridge ports.
 687  */
 688 static unsigned int br_nf_forward(void *priv,
 689                                   struct sk_buff *skb,
 690                                   const struct nf_hook_state *state)
 691 {
 692         if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
 693             is_pppoe_ip(skb, state->net))
 694                 return br_nf_forward_ip(skb, state, NFPROTO_IPV4);
 695         if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 696             is_pppoe_ipv6(skb, state->net))
 697                 return br_nf_forward_ip(skb, state, NFPROTO_IPV6);
 698         if (IS_ARP(skb) || is_vlan_arp(skb, state->net))
 699                 return br_nf_forward_arp(skb, state);
 700
 701         return NF_ACCEPT;
 702 }
 703
 704 static int br_nf_push_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
 705 {
 706         struct brnf_frag_data *data;
 707         int err;
 708
 709         data = this_cpu_ptr(&brnf_frag_data_storage);
 710         err = skb_cow_head(skb, data->size);
 711
 712         if (err) {
 713                 kfree_skb(skb);
 714                 return 0;
 715         }
 716
 717         if (data->vlan_proto)
 718                 __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci);
 719
 720         skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
 721         __skb_push(skb, data->encap_size);
 722
 723         nf_bridge_info_free(skb);
 724         return br_dev_queue_push_xmit(net, sk, skb);
 725 }
 726
 727 static int
 728 br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 729                   int (*output)(struct net *, struct sock *, struct sk_buff *))
 730 {
 731         unsigned int mtu = ip_skb_dst_mtu(sk, skb);
 732         struct iphdr *iph = ip_hdr(skb);
 733
 734         if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
 735                      (IPCB(skb)->frag_max_size &&
 736                       IPCB(skb)->frag_max_size > mtu))) {
 737                 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
 738                 kfree_skb(skb);
 739                 return -EMSGSIZE;
 740         }
 741
 742         return ip_do_fragment(net, sk, skb, output);
 743 }
 744
 745 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
 746 {
 747         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 748
 749         if (nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
 750                 return PPPOE_SES_HLEN;
 751         return 0;
 752 }
 753
 754 static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
 755 {
 756         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 757         unsigned int mtu, mtu_reserved;
 758
 759         mtu_reserved = nf_bridge_mtu_reduction(skb);
 760         mtu = skb->dev->mtu;
 761
 762         if (nf_bridge->pkt_otherhost) {
 763                 skb->pkt_type = PACKET_OTHERHOST;
 764                 nf_bridge->pkt_otherhost = false;
 765         }
 766
 767         if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
 768                 mtu = nf_bridge->frag_max_size;
 769
 770         nf_bridge_update_protocol(skb);
 771         nf_bridge_push_encap_header(skb);
 772
 773         if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
 774                 nf_bridge_info_free(skb);
 775                 return br_dev_queue_push_xmit(net, sk, skb);
 776         }
 777
 778         /* This is wrong! We should preserve the original fragment
 779          * boundaries by preserving frag_list rather than refragmenting.
 780          */
 781         if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) &&
 782             skb->protocol == htons(ETH_P_IP)) {
 783                 struct brnf_frag_data *data;
 784
 785                 if (br_validate_ipv4(net, skb))
 786                         goto drop;
 787
 788                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 789
 790                 data = this_cpu_ptr(&brnf_frag_data_storage);
 791
 792                 if (skb_vlan_tag_present(skb)) {
 793                         data->vlan_tci = skb->vlan_tci;
 794                         data->vlan_proto = skb->vlan_proto;
 795                 } else {
 796                         data->vlan_proto = 0;
 797                 }
 798
 799                 data->encap_size = nf_bridge_encap_header_len(skb);
 800                 data->size = ETH_HLEN + data->encap_size;
 801
 802                 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
 803                                                  data->size);
 804
 805                 return br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit);
 806         }
 807         if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) &&
 808             skb->protocol == htons(ETH_P_IPV6)) {
 809                 const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
 810                 struct brnf_frag_data *data;
 811
 812                 if (br_validate_ipv6(net, skb))
 813                         goto drop;
 814
 815                 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
 816
 817                 data = this_cpu_ptr(&brnf_frag_data_storage);
 818                 data->encap_size = nf_bridge_encap_header_len(skb);
 819                 data->size = ETH_HLEN + data->encap_size;
 820
 821                 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
 822                                                  data->size);
 823
 824                 if (v6ops)
 825                         return v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit);
 826
 827                 kfree_skb(skb);
 828                 return -EMSGSIZE;
 829         }
 830         nf_bridge_info_free(skb);
 831         return br_dev_queue_push_xmit(net, sk, skb);
 832  drop:
 833         kfree_skb(skb);
 834         return 0;
 835 }
 836
 837 /* PF_BRIDGE/POST_ROUTING ********************************************/
 838 static unsigned int br_nf_post_routing(void *priv,
 839                                        struct sk_buff *skb,
 840                                        const struct nf_hook_state *state)
 841 {
 842         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 843         struct net_device *realoutdev = bridge_parent(skb->dev);
 844         u_int8_t pf;
 845
 846         /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
 847          * on a bridge, but was delivered locally and is now being routed:
 848          *
 849          * POST_ROUTING was already invoked from the ip stack.
 850          */
 851         if (!nf_bridge || !nf_bridge->physoutdev)
 852                 return NF_ACCEPT;
 853
 854         if (!realoutdev)
 855                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 856
 857         if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
 858             is_pppoe_ip(skb, state->net))
 859                 pf = NFPROTO_IPV4;
 860         else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 861                  is_pppoe_ipv6(skb, state->net))
 862                 pf = NFPROTO_IPV6;
 863         else
 864                 return NF_ACCEPT;
 865
 866         if (skb->pkt_type == PACKET_OTHERHOST) {
 867                 skb->pkt_type = PACKET_HOST;
 868                 nf_bridge->pkt_otherhost = true;
 869         }
 870
 871         nf_bridge_pull_encap_header(skb);
 872         if (pf == NFPROTO_IPV4)
 873                 skb->protocol = htons(ETH_P_IP);
 874         else
 875                 skb->protocol = htons(ETH_P_IPV6);
 876
 877         NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
 878                 NULL, realoutdev,
 879                 br_nf_dev_queue_xmit);
 880
 881         return NF_STOLEN;
 882 }
 883
 884 /* IP/SABOTAGE *****************************************************/
 885 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
 886  * for the second time. */
 887 static unsigned int ip_sabotage_in(void *priv,
 888                                    struct sk_buff *skb,
 889                                    const struct nf_hook_state *state)
 890 {
 891         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 892
 893         if (nf_bridge) {
 894                 if (nf_bridge->sabotage_in_done)
 895                         return NF_ACCEPT;
 896
 897                 if (!nf_bridge->in_prerouting &&
 898                     !netif_is_l3_master(skb->dev) &&
 899                     !netif_is_l3_slave(skb->dev)) {
 900                         nf_bridge->sabotage_in_done = 1;
 901                         state->okfn(state->net, state->sk, skb);
 902                         return NF_STOLEN;
 903                 }
 904         }
 905
 906         return NF_ACCEPT;
 907 }
 908
 909 /* This is called when br_netfilter has called into iptables/netfilter,
 910  * and DNAT has taken place on a bridge-forwarded packet.
 911  *
 912  * neigh->output has created a new MAC header, with local br0 MAC
 913  * as saddr.
 914  *
 915  * This restores the original MAC saddr of the bridged packet
 916  * before invoking bridge forward logic to transmit the packet.
 917  */
 918 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
 919 {
 920         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 921         struct net_device *br_indev;
 922
 923         br_indev = nf_bridge_get_physindev(skb, dev_net(skb->dev));
 924         if (!br_indev) {
 925                 kfree_skb(skb);
 926                 return;
 927         }
 928
 929         skb_pull(skb, ETH_HLEN);
 930         nf_bridge->bridged_dnat = 0;
 931
 932         BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
 933
 934         skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
 935                                        nf_bridge->neigh_header,
 936                                        ETH_HLEN - ETH_ALEN);
 937         skb->dev = br_indev;
 938
 939         nf_bridge->physoutdev = NULL;
 940         br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
 941 }
 942
 943 static int br_nf_dev_xmit(struct sk_buff *skb)
 944 {
 945         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 946
 947         if (nf_bridge && nf_bridge->bridged_dnat) {
 948                 br_nf_pre_routing_finish_bridge_slow(skb);
 949                 return 1;
 950         }
 951         return 0;
 952 }
 953
 954 static const struct nf_br_ops br_ops = {
 955         .br_dev_xmit_hook =     br_nf_dev_xmit,
 956 };
 957
 958 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
 959  * br_dev_queue_push_xmit is called afterwards */
 960 static const struct nf_hook_ops br_nf_ops[] = {
 961         {
 962                 .hook = br_nf_pre_routing,
 963                 .pf = NFPROTO_BRIDGE,
 964                 .hooknum = NF_BR_PRE_ROUTING,
 965                 .priority = NF_BR_PRI_BRNF,
 966         },
 967         {
 968                 .hook = br_nf_forward,
 969                 .pf = NFPROTO_BRIDGE,
 970                 .hooknum = NF_BR_FORWARD,
 971                 .priority = NF_BR_PRI_BRNF,
 972         },
 973         {
 974                 .hook = br_nf_post_routing,
 975                 .pf = NFPROTO_BRIDGE,
 976                 .hooknum = NF_BR_POST_ROUTING,
 977                 .priority = NF_BR_PRI_LAST,
 978         },
 979         {
 980                 .hook = ip_sabotage_in,
 981                 .pf = NFPROTO_IPV4,
 982                 .hooknum = NF_INET_PRE_ROUTING,
 983                 .priority = NF_IP_PRI_FIRST,
 984         },
 985         {
 986                 .hook = ip_sabotage_in,
 987                 .pf = NFPROTO_IPV6,
 988                 .hooknum = NF_INET_PRE_ROUTING,
 989                 .priority = NF_IP6_PRI_FIRST,
 990         },
 991 };
 992
 993 static int brnf_device_event(struct notifier_block *unused, unsigned long event,
 994                              void *ptr)
 995 {
 996         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 997         struct brnf_net *brnet;
 998         struct net *net;
 999         int ret;
1000
1001         if (event != NETDEV_REGISTER || !netif_is_bridge_master(dev))
1002                 return NOTIFY_DONE;
1003
1004         ASSERT_RTNL();
1005
1006         net = dev_net(dev);
1007         brnet = net_generic(net, brnf_net_id);
1008         if (brnet->enabled)
1009                 return NOTIFY_OK;
1010
1011         ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1012         if (ret)
1013                 return NOTIFY_BAD;
1014
1015         brnet->enabled = true;
1016         return NOTIFY_OK;
1017 }
1018
1019 static struct notifier_block brnf_notifier __read_mostly = {
1020         .notifier_call = brnf_device_event,
1021 };
1022
1023 /* recursively invokes nf_hook_slow (again), skipping already-called
1024  * hooks (< NF_BR_PRI_BRNF).
1025  *
1026  * Called with rcu read lock held.
1027  */
1028 int br_nf_hook_thresh(unsigned int hook, struct net *net,
1029                       struct sock *sk, struct sk_buff *skb,
1030                       struct net_device *indev,
1031                       struct net_device *outdev,
1032                       int (*okfn)(struct net *, struct sock *,
1033                                   struct sk_buff *))
1034 {
1035         const struct nf_hook_entries *e;
1036         struct nf_hook_state state;
1037         struct nf_hook_ops **ops;
1038         unsigned int i;
1039         int ret;
1040
1041         e = rcu_dereference(net->nf.hooks_bridge[hook]);
1042         if (!e)
1043                 return okfn(net, sk, skb);
1044
1045         ops = nf_hook_entries_get_hook_ops(e);
1046         for (i = 0; i < e->num_hook_entries; i++) {
1047                 /* These hooks have already been called */
1048                 if (ops[i]->priority < NF_BR_PRI_BRNF)
1049                         continue;
1050
1051                 /* These hooks have not been called yet, run them. */
1052                 if (ops[i]->priority > NF_BR_PRI_BRNF)
1053                         break;
1054
1055                 /* take a closer look at NF_BR_PRI_BRNF. */
1056                 if (ops[i]->hook == br_nf_pre_routing) {
1057                         /* This hook diverted the skb to this function,
1058                          * hooks after this have not been run yet.
1059                          */
1060                         i++;
1061                         break;
1062                 }
1063         }
1064
1065         nf_hook_state_init(&state, hook, NFPROTO_BRIDGE, indev, outdev,
1066                            sk, net, okfn);
1067
1068         ret = nf_hook_slow(skb, &state, e, i);
1069         if (ret == 1)
1070                 ret = okfn(net, sk, skb);
1071
1072         return ret;
1073 }
1074
1075 #ifdef CONFIG_SYSCTL
1076 static
1077 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
1078                             void *buffer, size_t *lenp, loff_t *ppos)
1079 {
1080         int ret;
1081
1082         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1083
1084         if (write && *(int *)(ctl->data))
1085                 *(int *)(ctl->data) = 1;
1086         return ret;
1087 }
1088
1089 static struct ctl_table brnf_table[] = {
1090         {
1091                 .procname       = "bridge-nf-call-arptables",
1092                 .maxlen         = sizeof(int),
1093                 .mode           = 0644,
1094                 .proc_handler   = brnf_sysctl_call_tables,
1095         },
1096         {
1097                 .procname       = "bridge-nf-call-iptables",
1098                 .maxlen         = sizeof(int),
1099                 .mode           = 0644,
1100                 .proc_handler   = brnf_sysctl_call_tables,
1101         },
1102         {
1103                 .procname       = "bridge-nf-call-ip6tables",
1104                 .maxlen         = sizeof(int),
1105                 .mode           = 0644,
1106                 .proc_handler   = brnf_sysctl_call_tables,
1107         },
1108         {
1109                 .procname       = "bridge-nf-filter-vlan-tagged",
1110                 .maxlen         = sizeof(int),
1111                 .mode           = 0644,
1112                 .proc_handler   = brnf_sysctl_call_tables,
1113         },
1114         {
1115                 .procname       = "bridge-nf-filter-pppoe-tagged",
1116                 .maxlen         = sizeof(int),
1117                 .mode           = 0644,
1118                 .proc_handler   = brnf_sysctl_call_tables,
1119         },
1120         {
1121                 .procname       = "bridge-nf-pass-vlan-input-dev",
1122                 .maxlen         = sizeof(int),
1123                 .mode           = 0644,
1124                 .proc_handler   = brnf_sysctl_call_tables,
1125         },
1126         { }
1127 };
1128
1129 static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
1130 {
1131         brnf->call_iptables = 1;
1132         brnf->call_ip6tables = 1;
1133         brnf->call_arptables = 1;
1134         brnf->filter_vlan_tagged = 0;
1135         brnf->filter_pppoe_tagged = 0;
1136         brnf->pass_vlan_indev = 0;
1137 }
1138
1139 static int br_netfilter_sysctl_init_net(struct net *net)
1140 {
1141         struct ctl_table *table = brnf_table;
1142         struct brnf_net *brnet;
1143
1144         if (!net_eq(net, &init_net)) {
1145                 table = kmemdup(table, sizeof(brnf_table), GFP_KERNEL);
1146                 if (!table)
1147                         return -ENOMEM;
1148         }
1149
1150         brnet = net_generic(net, brnf_net_id);
1151         table[0].data = &brnet->call_arptables;
1152         table[1].data = &brnet->call_iptables;
1153         table[2].data = &brnet->call_ip6tables;
1154         table[3].data = &brnet->filter_vlan_tagged;
1155         table[4].data = &brnet->filter_pppoe_tagged;
1156         table[5].data = &brnet->pass_vlan_indev;
1157
1158         br_netfilter_sysctl_default(brnet);
1159
1160         brnet->ctl_hdr = register_net_sysctl_sz(net, "net/bridge", table,
1161                                                 ARRAY_SIZE(brnf_table));
1162         if (!brnet->ctl_hdr) {
1163                 if (!net_eq(net, &init_net))
1164                         kfree(table);
1165
1166                 return -ENOMEM;
1167         }
1168
1169         return 0;
1170 }
1171
1172 static void br_netfilter_sysctl_exit_net(struct net *net,
1173                                          struct brnf_net *brnet)
1174 {
1175         struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
1176
1177         unregister_net_sysctl_table(brnet->ctl_hdr);
1178         if (!net_eq(net, &init_net))
1179                 kfree(table);
1180 }
1181
1182 static int __net_init brnf_init_net(struct net *net)
1183 {
1184         return br_netfilter_sysctl_init_net(net);
1185 }
1186 #endif
1187
1188 static void __net_exit brnf_exit_net(struct net *net)
1189 {
1190         struct brnf_net *brnet;
1191
1192         brnet = net_generic(net, brnf_net_id);
1193         if (brnet->enabled) {
1194                 nf_unregister_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1195                 brnet->enabled = false;
1196         }
1197
1198 #ifdef CONFIG_SYSCTL
1199         br_netfilter_sysctl_exit_net(net, brnet);
1200 #endif
1201 }
1202
1203 static struct pernet_operations brnf_net_ops __read_mostly = {
1204 #ifdef CONFIG_SYSCTL
1205         .init = brnf_init_net,
1206 #endif
1207         .exit = brnf_exit_net,
1208         .id   = &brnf_net_id,
1209         .size = sizeof(struct brnf_net),
1210 };
1211
1212 static int __init br_netfilter_init(void)
1213 {
1214         int ret;
1215
1216         ret = register_pernet_subsys(&brnf_net_ops);
1217         if (ret < 0)
1218                 return ret;
1219
1220         ret = register_netdevice_notifier(&brnf_notifier);
1221         if (ret < 0) {
1222                 unregister_pernet_subsys(&brnf_net_ops);
1223                 return ret;
1224         }
1225
1226         RCU_INIT_POINTER(nf_br_ops, &br_ops);
1227         printk(KERN_NOTICE "Bridge firewalling registered\n");
1228         return 0;
1229 }
1230
1231 static void __exit br_netfilter_fini(void)
1232 {
1233         RCU_INIT_POINTER(nf_br_ops, NULL);
1234         unregister_netdevice_notifier(&brnf_notifier);
1235         unregister_pernet_subsys(&brnf_net_ops);
1236 }
1237
1238 module_init(br_netfilter_init);
1239 module_exit(br_netfilter_fini);
1240
1241 MODULE_LICENSE("GPL");
1242 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1243 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1244 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");