net/bridge/br_netfilter.c

   1 /*
   2  *      Handle firewalling
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *      Bart De Schuymer                <bdschuym@pandora.be>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Lennert dedicates this file to Kerstin Wurdinger.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/slab.h>
  20 #include <linux/ip.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/if_arp.h>
  24 #include <linux/if_ether.h>
  25 #include <linux/if_vlan.h>
  26 #include <linux/if_pppox.h>
  27 #include <linux/ppp_defs.h>
  28 #include <linux/netfilter_bridge.h>
  29 #include <linux/netfilter_ipv4.h>
  30 #include <linux/netfilter_ipv6.h>
  31 #include <linux/netfilter_arp.h>
  32 #include <linux/in_route.h>
  33 #include <linux/inetdevice.h>
  34
  35 #include <net/ip.h>
  36 #include <net/ipv6.h>
  37 #include <net/route.h>
  38 #include <net/netfilter/br_netfilter.h>
  39
  40 #include <asm/uaccess.h>
  41 #include "br_private.h"
  42 #ifdef CONFIG_SYSCTL
  43 #include <linux/sysctl.h>
  44 #endif
  45
  46 #ifdef CONFIG_SYSCTL
  47 static struct ctl_table_header *brnf_sysctl_header;
  48 static int brnf_call_iptables __read_mostly = 1;
  49 static int brnf_call_ip6tables __read_mostly = 1;
  50 static int brnf_call_arptables __read_mostly = 1;
  51 static int brnf_filter_vlan_tagged __read_mostly = 0;
  52 static int brnf_filter_pppoe_tagged __read_mostly = 0;
  53 static int brnf_pass_vlan_indev __read_mostly = 0;
  54 #else
  55 #define brnf_call_iptables 1
  56 #define brnf_call_ip6tables 1
  57 #define brnf_call_arptables 1
  58 #define brnf_filter_vlan_tagged 0
  59 #define brnf_filter_pppoe_tagged 0
  60 #define brnf_pass_vlan_indev 0
  61 #endif
  62
  63 #define IS_IP(skb) \
  64         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
  65
  66 #define IS_IPV6(skb) \
  67         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
  68
  69 #define IS_ARP(skb) \
  70         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
  71
  72 static inline __be16 vlan_proto(const struct sk_buff *skb)
  73 {
  74         if (skb_vlan_tag_present(skb))
  75                 return skb->protocol;
  76         else if (skb->protocol == htons(ETH_P_8021Q))
  77                 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
  78         else
  79                 return 0;
  80 }
  81
  82 #define IS_VLAN_IP(skb) \
  83         (vlan_proto(skb) == htons(ETH_P_IP) && \
  84          brnf_filter_vlan_tagged)
  85
  86 #define IS_VLAN_IPV6(skb) \
  87         (vlan_proto(skb) == htons(ETH_P_IPV6) && \
  88          brnf_filter_vlan_tagged)
  89
  90 #define IS_VLAN_ARP(skb) \
  91         (vlan_proto(skb) == htons(ETH_P_ARP) && \
  92          brnf_filter_vlan_tagged)
  93
  94 static inline __be16 pppoe_proto(const struct sk_buff *skb)
  95 {
  96         return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
  97                             sizeof(struct pppoe_hdr)));
  98 }
  99
 100 #define IS_PPPOE_IP(skb) \
 101         (skb->protocol == htons(ETH_P_PPP_SES) && \
 102          pppoe_proto(skb) == htons(PPP_IP) && \
 103          brnf_filter_pppoe_tagged)
 104
 105 #define IS_PPPOE_IPV6(skb) \
 106         (skb->protocol == htons(ETH_P_PPP_SES) && \
 107          pppoe_proto(skb) == htons(PPP_IPV6) && \
 108          brnf_filter_pppoe_tagged)
 109
 110 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
 111 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
 112
 113 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
 114 struct brnf_frag_data {
 115         char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
 116         u8 encap_size;
 117         u8 size;
 118 };
 119
 120 static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage);
 121 #endif
 122
 123 static struct nf_bridge_info *nf_bridge_info_get(const struct sk_buff *skb)
 124 {
 125         return skb->nf_bridge;
 126 }
 127
 128 static void nf_bridge_info_free(struct sk_buff *skb)
 129 {
 130         if (skb->nf_bridge) {
 131                 nf_bridge_put(skb->nf_bridge);
 132                 skb->nf_bridge = NULL;
 133         }
 134 }
 135
 136 static inline struct rtable *bridge_parent_rtable(const struct net_device *dev)
 137 {
 138         struct net_bridge_port *port;
 139
 140         port = br_port_get_rcu(dev);
 141         return port ? &port->br->fake_rtable : NULL;
 142 }
 143
 144 static inline struct net_device *bridge_parent(const struct net_device *dev)
 145 {
 146         struct net_bridge_port *port;
 147
 148         port = br_port_get_rcu(dev);
 149         return port ? port->br->dev : NULL;
 150 }
 151
 152 static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
 153 {
 154         skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
 155         if (likely(skb->nf_bridge))
 156                 atomic_set(&(skb->nf_bridge->use), 1);
 157
 158         return skb->nf_bridge;
 159 }
 160
 161 static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
 162 {
 163         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
 164
 165         if (atomic_read(&nf_bridge->use) > 1) {
 166                 struct nf_bridge_info *tmp = nf_bridge_alloc(skb);
 167
 168                 if (tmp) {
 169                         memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info));
 170                         atomic_set(&tmp->use, 1);
 171                 }
 172                 nf_bridge_put(nf_bridge);
 173                 nf_bridge = tmp;
 174         }
 175         return nf_bridge;
 176 }
 177
 178 static unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
 179 {
 180         switch (skb->protocol) {
 181         case __cpu_to_be16(ETH_P_8021Q):
 182                 return VLAN_HLEN;
 183         case __cpu_to_be16(ETH_P_PPP_SES):
 184                 return PPPOE_SES_HLEN;
 185         default:
 186                 return 0;
 187         }
 188 }
 189
 190 static inline void nf_bridge_push_encap_header(struct sk_buff *skb)
 191 {
 192         unsigned int len = nf_bridge_encap_header_len(skb);
 193
 194         skb_push(skb, len);
 195         skb->network_header -= len;
 196 }
 197
 198 static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
 199 {
 200         unsigned int len = nf_bridge_encap_header_len(skb);
 201
 202         skb_pull(skb, len);
 203         skb->network_header += len;
 204 }
 205
 206 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
 207 {
 208         unsigned int len = nf_bridge_encap_header_len(skb);
 209
 210         skb_pull_rcsum(skb, len);
 211         skb->network_header += len;
 212 }
 213
 214 /* When handing a packet over to the IP layer
 215  * check whether we have a skb that is in the
 216  * expected format
 217  */
 218
 219 static int br_validate_ipv4(struct sk_buff *skb)
 220 {
 221         const struct iphdr *iph;
 222         struct net_device *dev = skb->dev;
 223         u32 len;
 224
 225         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 226                 goto inhdr_error;
 227
 228         iph = ip_hdr(skb);
 229
 230         /* Basic sanity checks */
 231         if (iph->ihl < 5 || iph->version != 4)
 232                 goto inhdr_error;
 233
 234         if (!pskb_may_pull(skb, iph->ihl*4))
 235                 goto inhdr_error;
 236
 237         iph = ip_hdr(skb);
 238         if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
 239                 goto inhdr_error;
 240
 241         len = ntohs(iph->tot_len);
 242         if (skb->len < len) {
 243                 IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INTRUNCATEDPKTS);
 244                 goto drop;
 245         } else if (len < (iph->ihl*4))
 246                 goto inhdr_error;
 247
 248         if (pskb_trim_rcsum(skb, len)) {
 249                 IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
 250                 goto drop;
 251         }
 252
 253         memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
 254         /* We should really parse IP options here but until
 255          * somebody who actually uses IP options complains to
 256          * us we'll just silently ignore the options because
 257          * we're lazy!
 258          */
 259         return 0;
 260
 261 inhdr_error:
 262         IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
 263 drop:
 264         return -1;
 265 }
 266
 267 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff
 268  * anyway
 269  */
 270 static int check_hbh_len(struct sk_buff *skb)
 271 {
 272         unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1);
 273         u32 pkt_len;
 274         const unsigned char *nh = skb_network_header(skb);
 275         int off = raw - nh;
 276         int len = (raw[1] + 1) << 3;
 277
 278         if ((raw + len) - skb->data > skb_headlen(skb))
 279                 goto bad;
 280
 281         off += 2;
 282         len -= 2;
 283
 284         while (len > 0) {
 285                 int optlen = nh[off + 1] + 2;
 286
 287                 switch (nh[off]) {
 288                 case IPV6_TLV_PAD1:
 289                         optlen = 1;
 290                         break;
 291
 292                 case IPV6_TLV_PADN:
 293                         break;
 294
 295                 case IPV6_TLV_JUMBO:
 296                         if (nh[off + 1] != 4 || (off & 3) != 2)
 297                                 goto bad;
 298                         pkt_len = ntohl(*(__be32 *)(nh + off + 2));
 299                         if (pkt_len <= IPV6_MAXPLEN ||
 300                             ipv6_hdr(skb)->payload_len)
 301                                 goto bad;
 302                         if (pkt_len > skb->len - sizeof(struct ipv6hdr))
 303                                 goto bad;
 304                         if (pskb_trim_rcsum(skb,
 305                                             pkt_len + sizeof(struct ipv6hdr)))
 306                                 goto bad;
 307                         nh = skb_network_header(skb);
 308                         break;
 309                 default:
 310                         if (optlen > len)
 311                                 goto bad;
 312                         break;
 313                 }
 314                 off += optlen;
 315                 len -= optlen;
 316         }
 317         if (len == 0)
 318                 return 0;
 319 bad:
 320         return -1;
 321 }
 322
 323 static void nf_bridge_update_protocol(struct sk_buff *skb)
 324 {
 325         switch (skb->nf_bridge->orig_proto) {
 326         case BRNF_PROTO_8021Q:
 327                 skb->protocol = htons(ETH_P_8021Q);
 328                 break;
 329         case BRNF_PROTO_PPPOE:
 330                 skb->protocol = htons(ETH_P_PPP_SES);
 331                 break;
 332         case BRNF_PROTO_UNCHANGED:
 333                 break;
 334         }
 335 }
 336
 337 /* Obtain the correct destination MAC address, while preserving the original
 338  * source MAC address. If we already know this address, we just copy it. If we
 339  * don't, we use the neighbour framework to find out. In both cases, we make
 340  * sure that br_handle_frame_finish() is called afterwards.
 341  */
 342 static int br_nf_pre_routing_finish_bridge(struct sock *sk, struct sk_buff *skb)
 343 {
 344         struct neighbour *neigh;
 345         struct dst_entry *dst;
 346
 347         skb->dev = bridge_parent(skb->dev);
 348         if (!skb->dev)
 349                 goto free_skb;
 350         dst = skb_dst(skb);
 351         neigh = dst_neigh_lookup_skb(dst, skb);
 352         if (neigh) {
 353                 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 354                 int ret;
 355
 356                 if (neigh->hh.hh_len) {
 357                         neigh_hh_bridge(&neigh->hh, skb);
 358                         skb->dev = nf_bridge->physindev;
 359                         ret = br_handle_frame_finish(sk, skb);
 360                 } else {
 361                         /* the neighbour function below overwrites the complete
 362                          * MAC header, so we save the Ethernet source address and
 363                          * protocol number.
 364                          */
 365                         skb_copy_from_linear_data_offset(skb,
 366                                                          -(ETH_HLEN-ETH_ALEN),
 367                                                          nf_bridge->neigh_header,
 368                                                          ETH_HLEN-ETH_ALEN);
 369                         /* tell br_dev_xmit to continue with forwarding */
 370                         nf_bridge->mask |= BRNF_BRIDGED_DNAT;
 371                         /* FIXME Need to refragment */
 372                         ret = neigh->output(neigh, skb);
 373                 }
 374                 neigh_release(neigh);
 375                 return ret;
 376         }
 377 free_skb:
 378         kfree_skb(skb);
 379         return 0;
 380 }
 381
 382 static bool daddr_was_changed(const struct sk_buff *skb,
 383                               const struct nf_bridge_info *nf_bridge)
 384 {
 385         switch (skb->protocol) {
 386         case htons(ETH_P_IP):
 387                 return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr;
 388         case htons(ETH_P_IPV6):
 389                 return memcmp(&nf_bridge->ipv6_daddr, &ipv6_hdr(skb)->daddr,
 390                               sizeof(ipv6_hdr(skb)->daddr)) != 0;
 391         default:
 392                 return false;
 393         }
 394 }
 395
 396 /* PF_BRIDGE/PRE_ROUTING: Undo the changes made for ip6tables
 397  * PREROUTING and continue the bridge PRE_ROUTING hook. See comment
 398  * for br_nf_pre_routing_finish(), same logic is used here but
 399  * equivalent IPv6 function ip6_route_input() called indirectly.
 400  */
 401 static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
 402 {
 403         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 404         struct rtable *rt;
 405         struct net_device *dev = skb->dev;
 406         const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
 407
 408         if (nf_bridge->pkt_otherhost) {
 409                 skb->pkt_type = PACKET_OTHERHOST;
 410                 nf_bridge->pkt_otherhost = false;
 411         }
 412         nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
 413         if (daddr_was_changed(skb, nf_bridge)) {
 414                 skb_dst_drop(skb);
 415                 v6ops->route_input(skb);
 416
 417                 if (skb_dst(skb)->error) {
 418                         kfree_skb(skb);
 419                         return 0;
 420                 }
 421
 422                 if (skb_dst(skb)->dev == dev) {
 423                         skb->dev = nf_bridge->physindev;
 424                         nf_bridge_update_protocol(skb);
 425                         nf_bridge_push_encap_header(skb);
 426                         NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
 427                                        sk, skb, skb->dev, NULL,
 428                                        br_nf_pre_routing_finish_bridge,
 429                                        1);
 430                         return 0;
 431                 }
 432                 ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
 433                 skb->pkt_type = PACKET_HOST;
 434         } else {
 435                 rt = bridge_parent_rtable(nf_bridge->physindev);
 436                 if (!rt) {
 437                         kfree_skb(skb);
 438                         return 0;
 439                 }
 440                 skb_dst_set_noref(skb, &rt->dst);
 441         }
 442
 443         skb->dev = nf_bridge->physindev;
 444         nf_bridge_update_protocol(skb);
 445         nf_bridge_push_encap_header(skb);
 446         NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
 447                        skb->dev, NULL,
 448                        br_handle_frame_finish, 1);
 449
 450         return 0;
 451 }
 452
 453 /* This requires some explaining. If DNAT has taken place,
 454  * we will need to fix up the destination Ethernet address.
 455  * This is also true when SNAT takes place (for the reply direction).
 456  *
 457  * There are two cases to consider:
 458  * 1. The packet was DNAT'ed to a device in the same bridge
 459  *    port group as it was received on. We can still bridge
 460  *    the packet.
 461  * 2. The packet was DNAT'ed to a different device, either
 462  *    a non-bridged device or another bridge port group.
 463  *    The packet will need to be routed.
 464  *
 465  * The correct way of distinguishing between these two cases is to
 466  * call ip_route_input() and to look at skb->dst->dev, which is
 467  * changed to the destination device if ip_route_input() succeeds.
 468  *
 469  * Let's first consider the case that ip_route_input() succeeds:
 470  *
 471  * If the output device equals the logical bridge device the packet
 472  * came in on, we can consider this bridging. The corresponding MAC
 473  * address will be obtained in br_nf_pre_routing_finish_bridge.
 474  * Otherwise, the packet is considered to be routed and we just
 475  * change the destination MAC address so that the packet will
 476  * later be passed up to the IP stack to be routed. For a redirected
 477  * packet, ip_route_input() will give back the localhost as output device,
 478  * which differs from the bridge device.
 479  *
 480  * Let's now consider the case that ip_route_input() fails:
 481  *
 482  * This can be because the destination address is martian, in which case
 483  * the packet will be dropped.
 484  * If IP forwarding is disabled, ip_route_input() will fail, while
 485  * ip_route_output_key() can return success. The source
 486  * address for ip_route_output_key() is set to zero, so ip_route_output_key()
 487  * thinks we're handling a locally generated packet and won't care
 488  * if IP forwarding is enabled. If the output device equals the logical bridge
 489  * device, we proceed as if ip_route_input() succeeded. If it differs from the
 490  * logical bridge port or if ip_route_output_key() fails we drop the packet.
 491  */
 492 static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 493 {
 494         struct net_device *dev = skb->dev;
 495         struct iphdr *iph = ip_hdr(skb);
 496         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 497         struct rtable *rt;
 498         int err;
 499
 500         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 501
 502         if (nf_bridge->pkt_otherhost) {
 503                 skb->pkt_type = PACKET_OTHERHOST;
 504                 nf_bridge->pkt_otherhost = false;
 505         }
 506         nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
 507         if (daddr_was_changed(skb, nf_bridge)) {
 508                 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
 509                         struct in_device *in_dev = __in_dev_get_rcu(dev);
 510
 511                         /* If err equals -EHOSTUNREACH the error is due to a
 512                          * martian destination or due to the fact that
 513                          * forwarding is disabled. For most martian packets,
 514                          * ip_route_output_key() will fail. It won't fail for 2 types of
 515                          * martian destinations: loopback destinations and destination
 516                          * 0.0.0.0. In both cases the packet will be dropped because the
 517                          * destination is the loopback device and not the bridge. */
 518                         if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
 519                                 goto free_skb;
 520
 521                         rt = ip_route_output(dev_net(dev), iph->daddr, 0,
 522                                              RT_TOS(iph->tos), 0);
 523                         if (!IS_ERR(rt)) {
 524                                 /* - Bridged-and-DNAT'ed traffic doesn't
 525                                  *   require ip_forwarding. */
 526                                 if (rt->dst.dev == dev) {
 527                                         skb_dst_set(skb, &rt->dst);
 528                                         goto bridged_dnat;
 529                                 }
 530                                 ip_rt_put(rt);
 531                         }
 532 free_skb:
 533                         kfree_skb(skb);
 534                         return 0;
 535                 } else {
 536                         if (skb_dst(skb)->dev == dev) {
 537 bridged_dnat:
 538                                 skb->dev = nf_bridge->physindev;
 539                                 nf_bridge_update_protocol(skb);
 540                                 nf_bridge_push_encap_header(skb);
 541                                 NF_HOOK_THRESH(NFPROTO_BRIDGE,
 542                                                NF_BR_PRE_ROUTING,
 543                                                sk, skb, skb->dev, NULL,
 544                                                br_nf_pre_routing_finish_bridge,
 545                                                1);
 546                                 return 0;
 547                         }
 548                         ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
 549                         skb->pkt_type = PACKET_HOST;
 550                 }
 551         } else {
 552                 rt = bridge_parent_rtable(nf_bridge->physindev);
 553                 if (!rt) {
 554                         kfree_skb(skb);
 555                         return 0;
 556                 }
 557                 skb_dst_set_noref(skb, &rt->dst);
 558         }
 559
 560         skb->dev = nf_bridge->physindev;
 561         nf_bridge_update_protocol(skb);
 562         nf_bridge_push_encap_header(skb);
 563         NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
 564                        skb->dev, NULL,
 565                        br_handle_frame_finish, 1);
 566
 567         return 0;
 568 }
 569
 570 static struct net_device *brnf_get_logical_dev(struct sk_buff *skb, const struct net_device *dev)
 571 {
 572         struct net_device *vlan, *br;
 573
 574         br = bridge_parent(dev);
 575         if (brnf_pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
 576                 return br;
 577
 578         vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
 579                                     skb_vlan_tag_get(skb) & VLAN_VID_MASK);
 580
 581         return vlan ? vlan : br;
 582 }
 583
 584 /* Some common code for IPv4/IPv6 */
 585 static struct net_device *setup_pre_routing(struct sk_buff *skb)
 586 {
 587         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 588
 589         if (skb->pkt_type == PACKET_OTHERHOST) {
 590                 skb->pkt_type = PACKET_HOST;
 591                 nf_bridge->pkt_otherhost = true;
 592         }
 593
 594         nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
 595         nf_bridge->physindev = skb->dev;
 596         skb->dev = brnf_get_logical_dev(skb, skb->dev);
 597
 598         if (skb->protocol == htons(ETH_P_8021Q))
 599                 nf_bridge->orig_proto = BRNF_PROTO_8021Q;
 600         else if (skb->protocol == htons(ETH_P_PPP_SES))
 601                 nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
 602
 603         /* Must drop socket now because of tproxy. */
 604         skb_orphan(skb);
 605         return skb->dev;
 606 }
 607
 608 /* Replicate the checks that IPv6 does on packet reception and pass the packet
 609  * to ip6tables, which doesn't support NAT, so things are fairly simple. */
 610 static unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops *ops,
 611                                            struct sk_buff *skb,
 612                                            const struct nf_hook_state *state)
 613 {
 614         struct nf_bridge_info *nf_bridge;
 615         const struct ipv6hdr *hdr;
 616         u32 pkt_len;
 617
 618         if (skb->len < sizeof(struct ipv6hdr))
 619                 return NF_DROP;
 620
 621         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 622                 return NF_DROP;
 623
 624         hdr = ipv6_hdr(skb);
 625
 626         if (hdr->version != 6)
 627                 return NF_DROP;
 628
 629         pkt_len = ntohs(hdr->payload_len);
 630
 631         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
 632                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
 633                         return NF_DROP;
 634                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 635                         return NF_DROP;
 636         }
 637         if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
 638                 return NF_DROP;
 639
 640         nf_bridge_put(skb->nf_bridge);
 641         if (!nf_bridge_alloc(skb))
 642                 return NF_DROP;
 643         if (!setup_pre_routing(skb))
 644                 return NF_DROP;
 645
 646         nf_bridge = nf_bridge_info_get(skb);
 647         nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr;
 648
 649         skb->protocol = htons(ETH_P_IPV6);
 650         NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->sk, skb,
 651                 skb->dev, NULL,
 652                 br_nf_pre_routing_finish_ipv6);
 653
 654         return NF_STOLEN;
 655 }
 656
 657 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
 658  * Replicate the checks that IPv4 does on packet reception.
 659  * Set skb->dev to the bridge device (i.e. parent of the
 660  * receiving device) to make netfilter happy, the REDIRECT
 661  * target in particular.  Save the original destination IP
 662  * address to be able to detect DNAT afterwards. */
 663 static unsigned int br_nf_pre_routing(const struct nf_hook_ops *ops,
 664                                       struct sk_buff *skb,
 665                                       const struct nf_hook_state *state)
 666 {
 667         struct nf_bridge_info *nf_bridge;
 668         struct net_bridge_port *p;
 669         struct net_bridge *br;
 670         __u32 len = nf_bridge_encap_header_len(skb);
 671
 672         if (unlikely(!pskb_may_pull(skb, len)))
 673                 return NF_DROP;
 674
 675         p = br_port_get_rcu(state->in);
 676         if (p == NULL)
 677                 return NF_DROP;
 678         br = p->br;
 679
 680         if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb)) {
 681                 if (!brnf_call_ip6tables && !br->nf_call_ip6tables)
 682                         return NF_ACCEPT;
 683
 684                 nf_bridge_pull_encap_header_rcsum(skb);
 685                 return br_nf_pre_routing_ipv6(ops, skb, state);
 686         }
 687
 688         if (!brnf_call_iptables && !br->nf_call_iptables)
 689                 return NF_ACCEPT;
 690
 691         if (!IS_IP(skb) && !IS_VLAN_IP(skb) && !IS_PPPOE_IP(skb))
 692                 return NF_ACCEPT;
 693
 694         nf_bridge_pull_encap_header_rcsum(skb);
 695
 696         if (br_validate_ipv4(skb))
 697                 return NF_DROP;
 698
 699         nf_bridge_put(skb->nf_bridge);
 700         if (!nf_bridge_alloc(skb))
 701                 return NF_DROP;
 702         if (!setup_pre_routing(skb))
 703                 return NF_DROP;
 704
 705         nf_bridge = nf_bridge_info_get(skb);
 706         nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
 707
 708         skb->protocol = htons(ETH_P_IP);
 709
 710         NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->sk, skb,
 711                 skb->dev, NULL,
 712                 br_nf_pre_routing_finish);
 713
 714         return NF_STOLEN;
 715 }
 716
 717
 718 /* PF_BRIDGE/LOCAL_IN ************************************************/
 719 /* The packet is locally destined, which requires a real
 720  * dst_entry, so detach the fake one.  On the way up, the
 721  * packet would pass through PRE_ROUTING again (which already
 722  * took place when the packet entered the bridge), but we
 723  * register an IPv4 PRE_ROUTING 'sabotage' hook that will
 724  * prevent this from happening. */
 725 static unsigned int br_nf_local_in(const struct nf_hook_ops *ops,
 726                                    struct sk_buff *skb,
 727                                    const struct nf_hook_state *state)
 728 {
 729         br_drop_fake_rtable(skb);
 730         return NF_ACCEPT;
 731 }
 732
 733 /* PF_BRIDGE/FORWARD *************************************************/
 734 static int br_nf_forward_finish(struct sock *sk, struct sk_buff *skb)
 735 {
 736         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 737         struct net_device *in;
 738
 739         if (!IS_ARP(skb) && !IS_VLAN_ARP(skb)) {
 740
 741                 if (skb->protocol == htons(ETH_P_IP)) {
 742                         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 743                 }
 744
 745                 in = nf_bridge->physindev;
 746                 if (nf_bridge->pkt_otherhost) {
 747                         skb->pkt_type = PACKET_OTHERHOST;
 748                         nf_bridge->pkt_otherhost = false;
 749                 }
 750                 nf_bridge_update_protocol(skb);
 751         } else {
 752                 in = *((struct net_device **)(skb->cb));
 753         }
 754         nf_bridge_push_encap_header(skb);
 755
 756         NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, sk, skb,
 757                        in, skb->dev, br_forward_finish, 1);
 758         return 0;
 759 }
 760
 761
 762 /* This is the 'purely bridged' case.  For IP, we pass the packet to
 763  * netfilter with indev and outdev set to the bridge device,
 764  * but we are still able to filter on the 'real' indev/outdev
 765  * because of the physdev module. For ARP, indev and outdev are the
 766  * bridge ports. */
 767 static unsigned int br_nf_forward_ip(const struct nf_hook_ops *ops,
 768                                      struct sk_buff *skb,
 769                                      const struct nf_hook_state *state)
 770 {
 771         struct nf_bridge_info *nf_bridge;
 772         struct net_device *parent;
 773         u_int8_t pf;
 774
 775         if (!skb->nf_bridge)
 776                 return NF_ACCEPT;
 777
 778         /* Need exclusive nf_bridge_info since we might have multiple
 779          * different physoutdevs. */
 780         if (!nf_bridge_unshare(skb))
 781                 return NF_DROP;
 782
 783         nf_bridge = nf_bridge_info_get(skb);
 784         if (!nf_bridge)
 785                 return NF_DROP;
 786
 787         parent = bridge_parent(state->out);
 788         if (!parent)
 789                 return NF_DROP;
 790
 791         if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb))
 792                 pf = NFPROTO_IPV4;
 793         else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb))
 794                 pf = NFPROTO_IPV6;
 795         else
 796                 return NF_ACCEPT;
 797
 798         nf_bridge_pull_encap_header(skb);
 799
 800         if (skb->pkt_type == PACKET_OTHERHOST) {
 801                 skb->pkt_type = PACKET_HOST;
 802                 nf_bridge->pkt_otherhost = true;
 803         }
 804
 805         if (pf == NFPROTO_IPV4) {
 806                 if (br_validate_ipv4(skb))
 807                         return NF_DROP;
 808                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 809         }
 810
 811         nf_bridge->physoutdev = skb->dev;
 812         if (pf == NFPROTO_IPV4)
 813                 skb->protocol = htons(ETH_P_IP);
 814         else
 815                 skb->protocol = htons(ETH_P_IPV6);
 816
 817         NF_HOOK(pf, NF_INET_FORWARD, NULL, skb,
 818                 brnf_get_logical_dev(skb, state->in),
 819                 parent, br_nf_forward_finish);
 820
 821         return NF_STOLEN;
 822 }
 823
 824 static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops,
 825                                       struct sk_buff *skb,
 826                                       const struct nf_hook_state *state)
 827 {
 828         struct net_bridge_port *p;
 829         struct net_bridge *br;
 830         struct net_device **d = (struct net_device **)(skb->cb);
 831
 832         p = br_port_get_rcu(state->out);
 833         if (p == NULL)
 834                 return NF_ACCEPT;
 835         br = p->br;
 836
 837         if (!brnf_call_arptables && !br->nf_call_arptables)
 838                 return NF_ACCEPT;
 839
 840         if (!IS_ARP(skb)) {
 841                 if (!IS_VLAN_ARP(skb))
 842                         return NF_ACCEPT;
 843                 nf_bridge_pull_encap_header(skb);
 844         }
 845
 846         if (arp_hdr(skb)->ar_pln != 4) {
 847                 if (IS_VLAN_ARP(skb))
 848                         nf_bridge_push_encap_header(skb);
 849                 return NF_ACCEPT;
 850         }
 851         *d = state->in;
 852         NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->sk, skb,
 853                 state->in, state->out, br_nf_forward_finish);
 854
 855         return NF_STOLEN;
 856 }
 857
 858 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
 859 static int br_nf_push_frag_xmit(struct sock *sk, struct sk_buff *skb)
 860 {
 861         struct brnf_frag_data *data;
 862         int err;
 863
 864         data = this_cpu_ptr(&brnf_frag_data_storage);
 865         err = skb_cow_head(skb, data->size);
 866
 867         if (err) {
 868                 kfree_skb(skb);
 869                 return 0;
 870         }
 871
 872         skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
 873         __skb_push(skb, data->encap_size);
 874
 875         nf_bridge_info_free(skb);
 876         return br_dev_queue_push_xmit(sk, skb);
 877 }
 878
 879 static int br_nf_ip_fragment(struct sock *sk, struct sk_buff *skb,
 880                              int (*output)(struct sock *, struct sk_buff *))
 881 {
 882         unsigned int mtu = ip_skb_dst_mtu(skb);
 883         struct iphdr *iph = ip_hdr(skb);
 884         struct rtable *rt = skb_rtable(skb);
 885         struct net_device *dev = rt->dst.dev;
 886
 887         if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
 888                      (IPCB(skb)->frag_max_size &&
 889                       IPCB(skb)->frag_max_size > mtu))) {
 890                 IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
 891                 kfree_skb(skb);
 892                 return -EMSGSIZE;
 893         }
 894
 895         return ip_do_fragment(sk, skb, output);
 896 }
 897
 898 static int br_nf_dev_queue_xmit(struct sock *sk, struct sk_buff *skb)
 899 {
 900         int ret;
 901         struct nf_bridge_info *nf_bridge;
 902         unsigned int mtu_reserved;
 903
 904         if (skb_is_gso(skb) || skb->protocol != htons(ETH_P_IP)) {
 905                 nf_bridge_info_free(skb);
 906                 return br_dev_queue_push_xmit(sk, skb);
 907         }
 908
 909         mtu_reserved = nf_bridge_mtu_reduction(skb);
 910         nf_bridge = nf_bridge_info_get(skb);
 911         /* This is wrong! We should preserve the original fragment
 912          * boundaries by preserving frag_list rather than refragmenting.
 913          */
 914         if (skb->len + mtu_reserved > skb->dev->mtu) {
 915                 struct brnf_frag_data *data;
 916
 917                 if (br_validate_ipv4(skb))
 918                         return NF_DROP;
 919
 920                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 921
 922                 nf_bridge_update_protocol(skb);
 923
 924                 data = this_cpu_ptr(&brnf_frag_data_storage);
 925                 data->encap_size = nf_bridge_encap_header_len(skb);
 926                 data->size = ETH_HLEN + data->encap_size;
 927
 928                 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
 929                                                  data->size);
 930
 931                 ret = br_nf_ip_fragment(sk, skb, br_nf_push_frag_xmit);
 932         } else {
 933                 nf_bridge_info_free(skb);
 934                 ret = br_dev_queue_push_xmit(sk, skb);
 935         }
 936
 937         return ret;
 938 }
 939 #else
 940 static int br_nf_dev_queue_xmit(struct sock *sk, struct sk_buff *skb)
 941 {
 942         nf_bridge_info_free(skb);
 943         return br_dev_queue_push_xmit(sk, skb);
 944 }
 945 #endif
 946
 947 /* PF_BRIDGE/POST_ROUTING ********************************************/
 948 static unsigned int br_nf_post_routing(const struct nf_hook_ops *ops,
 949                                        struct sk_buff *skb,
 950                                        const struct nf_hook_state *state)
 951 {
 952         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 953         struct net_device *realoutdev = bridge_parent(skb->dev);
 954         u_int8_t pf;
 955
 956         /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
 957          * on a bridge, but was delivered locally and is now being routed:
 958          *
 959          * POST_ROUTING was already invoked from the ip stack.
 960          */
 961         if (!nf_bridge || !nf_bridge->physoutdev)
 962                 return NF_ACCEPT;
 963
 964         if (!realoutdev)
 965                 return NF_DROP;
 966
 967         if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb))
 968                 pf = NFPROTO_IPV4;
 969         else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb))
 970                 pf = NFPROTO_IPV6;
 971         else
 972                 return NF_ACCEPT;
 973
 974         /* We assume any code from br_dev_queue_push_xmit onwards doesn't care
 975          * about the value of skb->pkt_type. */
 976         if (skb->pkt_type == PACKET_OTHERHOST) {
 977                 skb->pkt_type = PACKET_HOST;
 978                 nf_bridge->pkt_otherhost = true;
 979         }
 980
 981         nf_bridge_pull_encap_header(skb);
 982         if (pf == NFPROTO_IPV4)
 983                 skb->protocol = htons(ETH_P_IP);
 984         else
 985                 skb->protocol = htons(ETH_P_IPV6);
 986
 987         NF_HOOK(pf, NF_INET_POST_ROUTING, state->sk, skb,
 988                 NULL, realoutdev,
 989                 br_nf_dev_queue_xmit);
 990
 991         return NF_STOLEN;
 992 }
 993
 994 /* IP/SABOTAGE *****************************************************/
 995 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
 996  * for the second time. */
 997 static unsigned int ip_sabotage_in(const struct nf_hook_ops *ops,
 998                                    struct sk_buff *skb,
 999                                    const struct nf_hook_state *state)
1000 {
1001         if (skb->nf_bridge &&
1002             !(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
1003                 return NF_STOP;
1004         }
1005
1006         return NF_ACCEPT;
1007 }
1008
1009 /* This is called when br_netfilter has called into iptables/netfilter,
1010  * and DNAT has taken place on a bridge-forwarded packet.
1011  *
1012  * neigh->output has created a new MAC header, with local br0 MAC
1013  * as saddr.
1014  *
1015  * This restores the original MAC saddr of the bridged packet
1016  * before invoking bridge forward logic to transmit the packet.
1017  */
1018 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
1019 {
1020         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1021
1022         skb_pull(skb, ETH_HLEN);
1023         nf_bridge->mask &= ~BRNF_BRIDGED_DNAT;
1024
1025         BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
1026
1027         skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
1028                                        nf_bridge->neigh_header,
1029                                        ETH_HLEN - ETH_ALEN);
1030         skb->dev = nf_bridge->physindev;
1031
1032         nf_bridge->physoutdev = NULL;
1033         br_handle_frame_finish(NULL, skb);
1034 }
1035
1036 static int br_nf_dev_xmit(struct sk_buff *skb)
1037 {
1038         if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
1039                 br_nf_pre_routing_finish_bridge_slow(skb);
1040                 return 1;
1041         }
1042         return 0;
1043 }
1044
1045 static const struct nf_br_ops br_ops = {
1046         .br_dev_xmit_hook =     br_nf_dev_xmit,
1047 };
1048
1049 void br_netfilter_enable(void)
1050 {
1051 }
1052 EXPORT_SYMBOL_GPL(br_netfilter_enable);
1053
1054 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
1055  * br_dev_queue_push_xmit is called afterwards */
1056 static struct nf_hook_ops br_nf_ops[] __read_mostly = {
1057         {
1058                 .hook = br_nf_pre_routing,
1059                 .owner = THIS_MODULE,
1060                 .pf = NFPROTO_BRIDGE,
1061                 .hooknum = NF_BR_PRE_ROUTING,
1062                 .priority = NF_BR_PRI_BRNF,
1063         },
1064         {
1065                 .hook = br_nf_local_in,
1066                 .owner = THIS_MODULE,
1067                 .pf = NFPROTO_BRIDGE,
1068                 .hooknum = NF_BR_LOCAL_IN,
1069                 .priority = NF_BR_PRI_BRNF,
1070         },
1071         {
1072                 .hook = br_nf_forward_ip,
1073                 .owner = THIS_MODULE,
1074                 .pf = NFPROTO_BRIDGE,
1075                 .hooknum = NF_BR_FORWARD,
1076                 .priority = NF_BR_PRI_BRNF - 1,
1077         },
1078         {
1079                 .hook = br_nf_forward_arp,
1080                 .owner = THIS_MODULE,
1081                 .pf = NFPROTO_BRIDGE,
1082                 .hooknum = NF_BR_FORWARD,
1083                 .priority = NF_BR_PRI_BRNF,
1084         },
1085         {
1086                 .hook = br_nf_post_routing,
1087                 .owner = THIS_MODULE,
1088                 .pf = NFPROTO_BRIDGE,
1089                 .hooknum = NF_BR_POST_ROUTING,
1090                 .priority = NF_BR_PRI_LAST,
1091         },
1092         {
1093                 .hook = ip_sabotage_in,
1094                 .owner = THIS_MODULE,
1095                 .pf = NFPROTO_IPV4,
1096                 .hooknum = NF_INET_PRE_ROUTING,
1097                 .priority = NF_IP_PRI_FIRST,
1098         },
1099         {
1100                 .hook = ip_sabotage_in,
1101                 .owner = THIS_MODULE,
1102                 .pf = NFPROTO_IPV6,
1103                 .hooknum = NF_INET_PRE_ROUTING,
1104                 .priority = NF_IP6_PRI_FIRST,
1105         },
1106 };
1107
1108 #ifdef CONFIG_SYSCTL
1109 static
1110 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
1111                             void __user *buffer, size_t *lenp, loff_t *ppos)
1112 {
1113         int ret;
1114
1115         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1116
1117         if (write && *(int *)(ctl->data))
1118                 *(int *)(ctl->data) = 1;
1119         return ret;
1120 }
1121
1122 static struct ctl_table brnf_table[] = {
1123         {
1124                 .procname       = "bridge-nf-call-arptables",
1125                 .data           = &brnf_call_arptables,
1126                 .maxlen         = sizeof(int),
1127                 .mode           = 0644,
1128                 .proc_handler   = brnf_sysctl_call_tables,
1129         },
1130         {
1131                 .procname       = "bridge-nf-call-iptables",
1132                 .data           = &brnf_call_iptables,
1133                 .maxlen         = sizeof(int),
1134                 .mode           = 0644,
1135                 .proc_handler   = brnf_sysctl_call_tables,
1136         },
1137         {
1138                 .procname       = "bridge-nf-call-ip6tables",
1139                 .data           = &brnf_call_ip6tables,
1140                 .maxlen         = sizeof(int),
1141                 .mode           = 0644,
1142                 .proc_handler   = brnf_sysctl_call_tables,
1143         },
1144         {
1145                 .procname       = "bridge-nf-filter-vlan-tagged",
1146                 .data           = &brnf_filter_vlan_tagged,
1147                 .maxlen         = sizeof(int),
1148                 .mode           = 0644,
1149                 .proc_handler   = brnf_sysctl_call_tables,
1150         },
1151         {
1152                 .procname       = "bridge-nf-filter-pppoe-tagged",
1153                 .data           = &brnf_filter_pppoe_tagged,
1154                 .maxlen         = sizeof(int),
1155                 .mode           = 0644,
1156                 .proc_handler   = brnf_sysctl_call_tables,
1157         },
1158         {
1159                 .procname       = "bridge-nf-pass-vlan-input-dev",
1160                 .data           = &brnf_pass_vlan_indev,
1161                 .maxlen         = sizeof(int),
1162                 .mode           = 0644,
1163                 .proc_handler   = brnf_sysctl_call_tables,
1164         },
1165         { }
1166 };
1167 #endif
1168
1169 static int __init br_netfilter_init(void)
1170 {
1171         int ret;
1172
1173         ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1174         if (ret < 0)
1175                 return ret;
1176
1177 #ifdef CONFIG_SYSCTL
1178         brnf_sysctl_header = register_net_sysctl(&init_net, "net/bridge", brnf_table);
1179         if (brnf_sysctl_header == NULL) {
1180                 printk(KERN_WARNING
1181                        "br_netfilter: can't register to sysctl.\n");
1182                 nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1183                 return -ENOMEM;
1184         }
1185 #endif
1186         RCU_INIT_POINTER(nf_br_ops, &br_ops);
1187         printk(KERN_NOTICE "Bridge firewalling registered\n");
1188         return 0;
1189 }
1190
1191 static void __exit br_netfilter_fini(void)
1192 {
1193         RCU_INIT_POINTER(nf_br_ops, NULL);
1194         nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
1195 #ifdef CONFIG_SYSCTL
1196         unregister_net_sysctl_table(brnf_sysctl_header);
1197 #endif
1198 }
1199
1200 module_init(br_netfilter_init);
1201 module_exit(br_netfilter_fini);
1202
1203 MODULE_LICENSE("GPL");
1204 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1205 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1206 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");