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 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  47 #include <net/netfilter/nf_conntrack_core.h>
  48 #endif
  49
  50 static unsigned int brnf_net_id __read_mostly;
  51
  52 struct brnf_net {
  53         bool enabled;
  54
  55 #ifdef CONFIG_SYSCTL
  56         struct ctl_table_header *ctl_hdr;
  57 #endif
  58
  59         /* default value is 1 */
  60         int call_iptables;
  61         int call_ip6tables;
  62         int call_arptables;
  63
  64         /* default value is 0 */
  65         int filter_vlan_tagged;
  66         int filter_pppoe_tagged;
  67         int pass_vlan_indev;
  68 };
  69
  70 #define IS_IP(skb) \
  71         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
  72
  73 #define IS_IPV6(skb) \
  74         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
  75
  76 #define IS_ARP(skb) \
  77         (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
  78
  79 static inline __be16 vlan_proto(const struct sk_buff *skb)
  80 {
  81         if (skb_vlan_tag_present(skb))
  82                 return skb->protocol;
  83         else if (skb->protocol == htons(ETH_P_8021Q))
  84                 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
  85         else
  86                 return 0;
  87 }
  88
  89 static inline bool is_vlan_ip(const struct sk_buff *skb, const struct net *net)
  90 {
  91         struct brnf_net *brnet = net_generic(net, brnf_net_id);
  92
  93         return vlan_proto(skb) == htons(ETH_P_IP) && brnet->filter_vlan_tagged;
  94 }
  95
  96 static inline bool is_vlan_ipv6(const struct sk_buff *skb,
  97                                 const struct net *net)
  98 {
  99         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 100
 101         return vlan_proto(skb) == htons(ETH_P_IPV6) &&
 102                brnet->filter_vlan_tagged;
 103 }
 104
 105 static inline bool is_vlan_arp(const struct sk_buff *skb, const struct net *net)
 106 {
 107         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 108
 109         return vlan_proto(skb) == htons(ETH_P_ARP) && brnet->filter_vlan_tagged;
 110 }
 111
 112 static inline __be16 pppoe_proto(const struct sk_buff *skb)
 113 {
 114         return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
 115                             sizeof(struct pppoe_hdr)));
 116 }
 117
 118 static inline bool is_pppoe_ip(const struct sk_buff *skb, const struct net *net)
 119 {
 120         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 121
 122         return skb->protocol == htons(ETH_P_PPP_SES) &&
 123                pppoe_proto(skb) == htons(PPP_IP) && brnet->filter_pppoe_tagged;
 124 }
 125
 126 static inline bool is_pppoe_ipv6(const struct sk_buff *skb,
 127                                  const struct net *net)
 128 {
 129         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 130
 131         return skb->protocol == htons(ETH_P_PPP_SES) &&
 132                pppoe_proto(skb) == htons(PPP_IPV6) &&
 133                brnet->filter_pppoe_tagged;
 134 }
 135
 136 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
 137 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
 138
 139 struct brnf_frag_data {
 140         char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
 141         u8 encap_size;
 142         u8 size;
 143         u16 vlan_tci;
 144         __be16 vlan_proto;
 145 };
 146
 147 static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage);
 148
 149 static void nf_bridge_info_free(struct sk_buff *skb)
 150 {
 151         skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
 152 }
 153
 154 static inline struct net_device *bridge_parent(const struct net_device *dev)
 155 {
 156         struct net_bridge_port *port;
 157
 158         port = br_port_get_rcu(dev);
 159         return port ? port->br->dev : NULL;
 160 }
 161
 162 static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
 163 {
 164         return skb_ext_add(skb, SKB_EXT_BRIDGE_NF);
 165 }
 166
 167 unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
 168 {
 169         switch (skb->protocol) {
 170         case __cpu_to_be16(ETH_P_8021Q):
 171                 return VLAN_HLEN;
 172         case __cpu_to_be16(ETH_P_PPP_SES):
 173                 return PPPOE_SES_HLEN;
 174         default:
 175                 return 0;
 176         }
 177 }
 178
 179 static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
 180 {
 181         unsigned int len = nf_bridge_encap_header_len(skb);
 182
 183         skb_pull(skb, len);
 184         skb->network_header += len;
 185 }
 186
 187 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
 188 {
 189         unsigned int len = nf_bridge_encap_header_len(skb);
 190
 191         skb_pull_rcsum(skb, len);
 192         skb->network_header += len;
 193 }
 194
 195 /* When handing a packet over to the IP layer
 196  * check whether we have a skb that is in the
 197  * expected format
 198  */
 199
 200 static int br_validate_ipv4(struct net *net, struct sk_buff *skb)
 201 {
 202         const struct iphdr *iph;
 203         u32 len;
 204
 205         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 206                 goto inhdr_error;
 207
 208         iph = ip_hdr(skb);
 209
 210         /* Basic sanity checks */
 211         if (iph->ihl < 5 || iph->version != 4)
 212                 goto inhdr_error;
 213
 214         if (!pskb_may_pull(skb, iph->ihl*4))
 215                 goto inhdr_error;
 216
 217         iph = ip_hdr(skb);
 218         if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
 219                 goto csum_error;
 220
 221         len = skb_ip_totlen(skb);
 222         if (skb->len < len) {
 223                 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
 224                 goto drop;
 225         } else if (len < (iph->ihl*4))
 226                 goto inhdr_error;
 227
 228         if (pskb_trim_rcsum(skb, len)) {
 229                 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
 230                 goto drop;
 231         }
 232
 233         memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
 234         /* We should really parse IP options here but until
 235          * somebody who actually uses IP options complains to
 236          * us we'll just silently ignore the options because
 237          * we're lazy!
 238          */
 239         return 0;
 240
 241 csum_error:
 242         __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
 243 inhdr_error:
 244         __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
 245 drop:
 246         return -1;
 247 }
 248
 249 void nf_bridge_update_protocol(struct sk_buff *skb)
 250 {
 251         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 252
 253         switch (nf_bridge->orig_proto) {
 254         case BRNF_PROTO_8021Q:
 255                 skb->protocol = htons(ETH_P_8021Q);
 256                 break;
 257         case BRNF_PROTO_PPPOE:
 258                 skb->protocol = htons(ETH_P_PPP_SES);
 259                 break;
 260         case BRNF_PROTO_UNCHANGED:
 261                 break;
 262         }
 263 }
 264
 265 /* Obtain the correct destination MAC address, while preserving the original
 266  * source MAC address. If we already know this address, we just copy it. If we
 267  * don't, we use the neighbour framework to find out. In both cases, we make
 268  * sure that br_handle_frame_finish() is called afterwards.
 269  */
 270 int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_buff *skb)
 271 {
 272         struct neighbour *neigh;
 273         struct dst_entry *dst;
 274
 275         skb->dev = bridge_parent(skb->dev);
 276         if (!skb->dev)
 277                 goto free_skb;
 278         dst = skb_dst(skb);
 279         neigh = dst_neigh_lookup_skb(dst, skb);
 280         if (neigh) {
 281                 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 282                 int ret;
 283
 284                 if ((READ_ONCE(neigh->nud_state) & NUD_CONNECTED) &&
 285                     READ_ONCE(neigh->hh.hh_len)) {
 286                         struct net_device *br_indev;
 287
 288                         br_indev = nf_bridge_get_physindev(skb, net);
 289                         if (!br_indev) {
 290                                 neigh_release(neigh);
 291                                 goto free_skb;
 292                         }
 293
 294                         neigh_hh_bridge(&neigh->hh, skb);
 295                         skb->dev = br_indev;
 296
 297                         ret = br_handle_frame_finish(net, sk, skb);
 298                 } else {
 299                         /* the neighbour function below overwrites the complete
 300                          * MAC header, so we save the Ethernet source address and
 301                          * protocol number.
 302                          */
 303                         skb_copy_from_linear_data_offset(skb,
 304                                                          -(ETH_HLEN-ETH_ALEN),
 305                                                          nf_bridge->neigh_header,
 306                                                          ETH_HLEN-ETH_ALEN);
 307                         /* tell br_dev_xmit to continue with forwarding */
 308                         nf_bridge->bridged_dnat = 1;
 309                         /* FIXME Need to refragment */
 310                         ret = READ_ONCE(neigh->output)(neigh, skb);
 311                 }
 312                 neigh_release(neigh);
 313                 return ret;
 314         }
 315 free_skb:
 316         kfree_skb(skb);
 317         return 0;
 318 }
 319
 320 static inline bool
 321 br_nf_ipv4_daddr_was_changed(const struct sk_buff *skb,
 322                              const struct nf_bridge_info *nf_bridge)
 323 {
 324         return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr;
 325 }
 326
 327 /* This requires some explaining. If DNAT has taken place,
 328  * we will need to fix up the destination Ethernet address.
 329  * This is also true when SNAT takes place (for the reply direction).
 330  *
 331  * There are two cases to consider:
 332  * 1. The packet was DNAT'ed to a device in the same bridge
 333  *    port group as it was received on. We can still bridge
 334  *    the packet.
 335  * 2. The packet was DNAT'ed to a different device, either
 336  *    a non-bridged device or another bridge port group.
 337  *    The packet will need to be routed.
 338  *
 339  * The correct way of distinguishing between these two cases is to
 340  * call ip_route_input() and to look at skb->dst->dev, which is
 341  * changed to the destination device if ip_route_input() succeeds.
 342  *
 343  * Let's first consider the case that ip_route_input() succeeds:
 344  *
 345  * If the output device equals the logical bridge device the packet
 346  * came in on, we can consider this bridging. The corresponding MAC
 347  * address will be obtained in br_nf_pre_routing_finish_bridge.
 348  * Otherwise, the packet is considered to be routed and we just
 349  * change the destination MAC address so that the packet will
 350  * later be passed up to the IP stack to be routed. For a redirected
 351  * packet, ip_route_input() will give back the localhost as output device,
 352  * which differs from the bridge device.
 353  *
 354  * Let's now consider the case that ip_route_input() fails:
 355  *
 356  * This can be because the destination address is martian, in which case
 357  * the packet will be dropped.
 358  * If IP forwarding is disabled, ip_route_input() will fail, while
 359  * ip_route_output_key() can return success. The source
 360  * address for ip_route_output_key() is set to zero, so ip_route_output_key()
 361  * thinks we're handling a locally generated packet and won't care
 362  * if IP forwarding is enabled. If the output device equals the logical bridge
 363  * device, we proceed as if ip_route_input() succeeded. If it differs from the
 364  * logical bridge port or if ip_route_output_key() fails we drop the packet.
 365  */
 366 static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 367 {
 368         struct net_device *dev = skb->dev, *br_indev;
 369         struct iphdr *iph = ip_hdr(skb);
 370         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 371         struct rtable *rt;
 372         int err;
 373
 374         br_indev = nf_bridge_get_physindev(skb, net);
 375         if (!br_indev) {
 376                 kfree_skb(skb);
 377                 return 0;
 378         }
 379
 380         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 381
 382         if (nf_bridge->pkt_otherhost) {
 383                 skb->pkt_type = PACKET_OTHERHOST;
 384                 nf_bridge->pkt_otherhost = false;
 385         }
 386         nf_bridge->in_prerouting = 0;
 387         if (br_nf_ipv4_daddr_was_changed(skb, nf_bridge)) {
 388                 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
 389                         struct in_device *in_dev = __in_dev_get_rcu(dev);
 390
 391                         /* If err equals -EHOSTUNREACH the error is due to a
 392                          * martian destination or due to the fact that
 393                          * forwarding is disabled. For most martian packets,
 394                          * ip_route_output_key() will fail. It won't fail for 2 types of
 395                          * martian destinations: loopback destinations and destination
 396                          * 0.0.0.0. In both cases the packet will be dropped because the
 397                          * destination is the loopback device and not the bridge. */
 398                         if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
 399                                 goto free_skb;
 400
 401                         rt = ip_route_output(net, iph->daddr, 0,
 402                                              RT_TOS(iph->tos), 0,
 403                                              RT_SCOPE_UNIVERSE);
 404                         if (!IS_ERR(rt)) {
 405                                 /* - Bridged-and-DNAT'ed traffic doesn't
 406                                  *   require ip_forwarding. */
 407                                 if (rt->dst.dev == dev) {
 408                                         skb_dst_drop(skb);
 409                                         skb_dst_set(skb, &rt->dst);
 410                                         goto bridged_dnat;
 411                                 }
 412                                 ip_rt_put(rt);
 413                         }
 414 free_skb:
 415                         kfree_skb(skb);
 416                         return 0;
 417                 } else {
 418                         if (skb_dst(skb)->dev == dev) {
 419 bridged_dnat:
 420                                 skb->dev = br_indev;
 421                                 nf_bridge_update_protocol(skb);
 422                                 nf_bridge_push_encap_header(skb);
 423                                 br_nf_hook_thresh(NF_BR_PRE_ROUTING,
 424                                                   net, sk, skb, skb->dev,
 425                                                   NULL,
 426                                                   br_nf_pre_routing_finish_bridge);
 427                                 return 0;
 428                         }
 429                         ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
 430                         skb->pkt_type = PACKET_HOST;
 431                 }
 432         } else {
 433                 rt = bridge_parent_rtable(br_indev);
 434                 if (!rt) {
 435                         kfree_skb(skb);
 436                         return 0;
 437                 }
 438                 skb_dst_drop(skb);
 439                 skb_dst_set_noref(skb, &rt->dst);
 440         }
 441
 442         skb->dev = br_indev;
 443         nf_bridge_update_protocol(skb);
 444         nf_bridge_push_encap_header(skb);
 445         br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
 446                           br_handle_frame_finish);
 447         return 0;
 448 }
 449
 450 static struct net_device *brnf_get_logical_dev(struct sk_buff *skb,
 451                                                const struct net_device *dev,
 452                                                const struct net *net)
 453 {
 454         struct net_device *vlan, *br;
 455         struct brnf_net *brnet = net_generic(net, brnf_net_id);
 456
 457         br = bridge_parent(dev);
 458
 459         if (brnet->pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
 460                 return br;
 461
 462         vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
 463                                     skb_vlan_tag_get(skb) & VLAN_VID_MASK);
 464
 465         return vlan ? vlan : br;
 466 }
 467
 468 /* Some common code for IPv4/IPv6 */
 469 struct net_device *setup_pre_routing(struct sk_buff *skb, const struct net *net)
 470 {
 471         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 472
 473         if (skb->pkt_type == PACKET_OTHERHOST) {
 474                 skb->pkt_type = PACKET_HOST;
 475                 nf_bridge->pkt_otherhost = true;
 476         }
 477
 478         nf_bridge->in_prerouting = 1;
 479         nf_bridge->physinif = skb->dev->ifindex;
 480         skb->dev = brnf_get_logical_dev(skb, skb->dev, net);
 481
 482         if (skb->protocol == htons(ETH_P_8021Q))
 483                 nf_bridge->orig_proto = BRNF_PROTO_8021Q;
 484         else if (skb->protocol == htons(ETH_P_PPP_SES))
 485                 nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
 486
 487         /* Must drop socket now because of tproxy. */
 488         skb_orphan(skb);
 489         return skb->dev;
 490 }
 491
 492 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
 493  * Replicate the checks that IPv4 does on packet reception.
 494  * Set skb->dev to the bridge device (i.e. parent of the
 495  * receiving device) to make netfilter happy, the REDIRECT
 496  * target in particular.  Save the original destination IP
 497  * address to be able to detect DNAT afterwards. */
 498 static unsigned int br_nf_pre_routing(void *priv,
 499                                       struct sk_buff *skb,
 500                                       const struct nf_hook_state *state)
 501 {
 502         struct nf_bridge_info *nf_bridge;
 503         struct net_bridge_port *p;
 504         struct net_bridge *br;
 505         __u32 len = nf_bridge_encap_header_len(skb);
 506         struct brnf_net *brnet;
 507
 508         if (unlikely(!pskb_may_pull(skb, len)))
 509                 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
 510
 511         p = br_port_get_rcu(state->in);
 512         if (p == NULL)
 513                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 514         br = p->br;
 515
 516         brnet = net_generic(state->net, brnf_net_id);
 517         if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 518             is_pppoe_ipv6(skb, state->net)) {
 519                 if (!brnet->call_ip6tables &&
 520                     !br_opt_get(br, BROPT_NF_CALL_IP6TABLES))
 521                         return NF_ACCEPT;
 522                 if (!ipv6_mod_enabled()) {
 523                         pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
 524                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IPV6DISABLED, 0);
 525                 }
 526
 527                 nf_bridge_pull_encap_header_rcsum(skb);
 528                 return br_nf_pre_routing_ipv6(priv, skb, state);
 529         }
 530
 531         if (!brnet->call_iptables && !br_opt_get(br, BROPT_NF_CALL_IPTABLES))
 532                 return NF_ACCEPT;
 533
 534         if (!IS_IP(skb) && !is_vlan_ip(skb, state->net) &&
 535             !is_pppoe_ip(skb, state->net))
 536                 return NF_ACCEPT;
 537
 538         nf_bridge_pull_encap_header_rcsum(skb);
 539
 540         if (br_validate_ipv4(state->net, skb))
 541                 return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 542
 543         if (!nf_bridge_alloc(skb))
 544                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 545         if (!setup_pre_routing(skb, state->net))
 546                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 547
 548         nf_bridge = nf_bridge_info_get(skb);
 549         nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
 550
 551         skb->protocol = htons(ETH_P_IP);
 552         skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
 553
 554         NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 555                 skb->dev, NULL,
 556                 br_nf_pre_routing_finish);
 557
 558         return NF_STOLEN;
 559 }
 560
 561 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 562 /* conntracks' nf_confirm logic cannot handle cloned skbs referencing
 563  * the same nf_conn entry, which will happen for multicast (broadcast)
 564  * Frames on bridges.
 565  *
 566  * Example:
 567  *      macvlan0
 568  *      br0
 569  *  ethX  ethY
 570  *
 571  * ethX (or Y) receives multicast or broadcast packet containing
 572  * an IP packet, not yet in conntrack table.
 573  *
 574  * 1. skb passes through bridge and fake-ip (br_netfilter)Prerouting.
 575  *    -> skb->_nfct now references a unconfirmed entry
 576  * 2. skb is broad/mcast packet. bridge now passes clones out on each bridge
 577  *    interface.
 578  * 3. skb gets passed up the stack.
 579  * 4. In macvlan case, macvlan driver retains clone(s) of the mcast skb
 580  *    and schedules a work queue to send them out on the lower devices.
 581  *
 582  *    The clone skb->_nfct is not a copy, it is the same entry as the
 583  *    original skb.  The macvlan rx handler then returns RX_HANDLER_PASS.
 584  * 5. Normal conntrack hooks (in NF_INET_LOCAL_IN) confirm the orig skb.
 585  *
 586  * The Macvlan broadcast worker and normal confirm path will race.
 587  *
 588  * This race will not happen if step 2 already confirmed a clone. In that
 589  * case later steps perform skb_clone() with skb->_nfct already confirmed (in
 590  * hash table).  This works fine.
 591  *
 592  * But such confirmation won't happen when eb/ip/nftables rules dropped the
 593  * packets before they reached the nf_confirm step in postrouting.
 594  *
 595  * Work around this problem by explicit confirmation of the entry at
 596  * LOCAL_IN time, before upper layer has a chance to clone the unconfirmed
 597  * entry.
 598  *
 599  */
 600 static unsigned int br_nf_local_in(void *priv,
 601                                    struct sk_buff *skb,
 602                                    const struct nf_hook_state *state)
 603 {
 604         bool promisc = BR_INPUT_SKB_CB(skb)->promisc;
 605         struct nf_conntrack *nfct = skb_nfct(skb);
 606         const struct nf_ct_hook *ct_hook;
 607         struct nf_conn *ct;
 608         int ret;
 609
 610         if (promisc) {
 611                 nf_reset_ct(skb);
 612                 return NF_ACCEPT;
 613         }
 614
 615         if (!nfct || skb->pkt_type == PACKET_HOST)
 616                 return NF_ACCEPT;
 617
 618         ct = container_of(nfct, struct nf_conn, ct_general);
 619         if (likely(nf_ct_is_confirmed(ct)))
 620                 return NF_ACCEPT;
 621
 622         WARN_ON_ONCE(skb_shared(skb));
 623         WARN_ON_ONCE(refcount_read(&nfct->use) != 1);
 624
 625         /* We can't call nf_confirm here, it would create a dependency
 626          * on nf_conntrack module.
 627          */
 628         ct_hook = rcu_dereference(nf_ct_hook);
 629         if (!ct_hook) {
 630                 skb->_nfct = 0ul;
 631                 nf_conntrack_put(nfct);
 632                 return NF_ACCEPT;
 633         }
 634
 635         nf_bridge_pull_encap_header(skb);
 636         ret = ct_hook->confirm(skb);
 637         switch (ret & NF_VERDICT_MASK) {
 638         case NF_STOLEN:
 639                 return NF_STOLEN;
 640         default:
 641                 nf_bridge_push_encap_header(skb);
 642                 break;
 643         }
 644
 645         ct = container_of(nfct, struct nf_conn, ct_general);
 646         WARN_ON_ONCE(!nf_ct_is_confirmed(ct));
 647
 648         return ret;
 649 }
 650 #endif
 651
 652 /* PF_BRIDGE/FORWARD *************************************************/
 653 static int br_nf_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 654 {
 655         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 656         struct net_device *in;
 657
 658         if (!IS_ARP(skb) && !is_vlan_arp(skb, net)) {
 659
 660                 if (skb->protocol == htons(ETH_P_IP))
 661                         nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
 662
 663                 if (skb->protocol == htons(ETH_P_IPV6))
 664                         nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
 665
 666                 in = nf_bridge_get_physindev(skb, net);
 667                 if (!in) {
 668                         kfree_skb(skb);
 669                         return 0;
 670                 }
 671                 if (nf_bridge->pkt_otherhost) {
 672                         skb->pkt_type = PACKET_OTHERHOST;
 673                         nf_bridge->pkt_otherhost = false;
 674                 }
 675                 nf_bridge_update_protocol(skb);
 676         } else {
 677                 in = *((struct net_device **)(skb->cb));
 678         }
 679         nf_bridge_push_encap_header(skb);
 680
 681         br_nf_hook_thresh(NF_BR_FORWARD, net, sk, skb, in, skb->dev,
 682                           br_forward_finish);
 683         return 0;
 684 }
 685
 686
 687 static unsigned int br_nf_forward_ip(struct sk_buff *skb,
 688                                      const struct nf_hook_state *state,
 689                                      u8 pf)
 690 {
 691         struct nf_bridge_info *nf_bridge;
 692         struct net_device *parent;
 693
 694         nf_bridge = nf_bridge_info_get(skb);
 695         if (!nf_bridge)
 696                 return NF_ACCEPT;
 697
 698         /* Need exclusive nf_bridge_info since we might have multiple
 699          * different physoutdevs. */
 700         if (!nf_bridge_unshare(skb))
 701                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 702
 703         nf_bridge = nf_bridge_info_get(skb);
 704         if (!nf_bridge)
 705                 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
 706
 707         parent = bridge_parent(state->out);
 708         if (!parent)
 709                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 710
 711         nf_bridge_pull_encap_header(skb);
 712
 713         if (skb->pkt_type == PACKET_OTHERHOST) {
 714                 skb->pkt_type = PACKET_HOST;
 715                 nf_bridge->pkt_otherhost = true;
 716         }
 717
 718         if (pf == NFPROTO_IPV4) {
 719                 if (br_validate_ipv4(state->net, skb))
 720                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 721                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 722                 skb->protocol = htons(ETH_P_IP);
 723         } else if (pf == NFPROTO_IPV6) {
 724                 if (br_validate_ipv6(state->net, skb))
 725                         return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
 726                 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
 727                 skb->protocol = htons(ETH_P_IPV6);
 728         } else {
 729                 WARN_ON_ONCE(1);
 730                 return NF_DROP;
 731         }
 732
 733         nf_bridge->physoutdev = skb->dev;
 734
 735         NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
 736                 brnf_get_logical_dev(skb, state->in, state->net),
 737                 parent, br_nf_forward_finish);
 738
 739         return NF_STOLEN;
 740 }
 741
 742 static unsigned int br_nf_forward_arp(struct sk_buff *skb,
 743                                       const struct nf_hook_state *state)
 744 {
 745         struct net_bridge_port *p;
 746         struct net_bridge *br;
 747         struct net_device **d = (struct net_device **)(skb->cb);
 748         struct brnf_net *brnet;
 749
 750         p = br_port_get_rcu(state->out);
 751         if (p == NULL)
 752                 return NF_ACCEPT;
 753         br = p->br;
 754
 755         brnet = net_generic(state->net, brnf_net_id);
 756         if (!brnet->call_arptables && !br_opt_get(br, BROPT_NF_CALL_ARPTABLES))
 757                 return NF_ACCEPT;
 758
 759         if (is_vlan_arp(skb, state->net))
 760                 nf_bridge_pull_encap_header(skb);
 761
 762         if (unlikely(!pskb_may_pull(skb, sizeof(struct arphdr))))
 763                 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
 764
 765         if (arp_hdr(skb)->ar_pln != 4) {
 766                 if (is_vlan_arp(skb, state->net))
 767                         nf_bridge_push_encap_header(skb);
 768                 return NF_ACCEPT;
 769         }
 770         *d = state->in;
 771         NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
 772                 state->in, state->out, br_nf_forward_finish);
 773
 774         return NF_STOLEN;
 775 }
 776
 777 /* This is the 'purely bridged' case.  For IP, we pass the packet to
 778  * netfilter with indev and outdev set to the bridge device,
 779  * but we are still able to filter on the 'real' indev/outdev
 780  * because of the physdev module. For ARP, indev and outdev are the
 781  * bridge ports.
 782  */
 783 static unsigned int br_nf_forward(void *priv,
 784                                   struct sk_buff *skb,
 785                                   const struct nf_hook_state *state)
 786 {
 787         if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
 788             is_pppoe_ip(skb, state->net))
 789                 return br_nf_forward_ip(skb, state, NFPROTO_IPV4);
 790         if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 791             is_pppoe_ipv6(skb, state->net))
 792                 return br_nf_forward_ip(skb, state, NFPROTO_IPV6);
 793         if (IS_ARP(skb) || is_vlan_arp(skb, state->net))
 794                 return br_nf_forward_arp(skb, state);
 795
 796         return NF_ACCEPT;
 797 }
 798
 799 static int br_nf_push_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
 800 {
 801         struct brnf_frag_data *data;
 802         int err;
 803
 804         data = this_cpu_ptr(&brnf_frag_data_storage);
 805         err = skb_cow_head(skb, data->size);
 806
 807         if (err) {
 808                 kfree_skb(skb);
 809                 return 0;
 810         }
 811
 812         if (data->vlan_proto)
 813                 __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci);
 814
 815         skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
 816         __skb_push(skb, data->encap_size);
 817
 818         nf_bridge_info_free(skb);
 819         return br_dev_queue_push_xmit(net, sk, skb);
 820 }
 821
 822 static int
 823 br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 824                   int (*output)(struct net *, struct sock *, struct sk_buff *))
 825 {
 826         unsigned int mtu = ip_skb_dst_mtu(sk, skb);
 827         struct iphdr *iph = ip_hdr(skb);
 828
 829         if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
 830                      (IPCB(skb)->frag_max_size &&
 831                       IPCB(skb)->frag_max_size > mtu))) {
 832                 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
 833                 kfree_skb(skb);
 834                 return -EMSGSIZE;
 835         }
 836
 837         return ip_do_fragment(net, sk, skb, output);
 838 }
 839
 840 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
 841 {
 842         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 843
 844         if (nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
 845                 return PPPOE_SES_HLEN;
 846         return 0;
 847 }
 848
 849 static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
 850 {
 851         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 852         unsigned int mtu, mtu_reserved;
 853
 854         mtu_reserved = nf_bridge_mtu_reduction(skb);
 855         mtu = skb->dev->mtu;
 856
 857         if (nf_bridge->pkt_otherhost) {
 858                 skb->pkt_type = PACKET_OTHERHOST;
 859                 nf_bridge->pkt_otherhost = false;
 860         }
 861
 862         if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
 863                 mtu = nf_bridge->frag_max_size;
 864
 865         nf_bridge_update_protocol(skb);
 866         nf_bridge_push_encap_header(skb);
 867
 868         if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
 869                 nf_bridge_info_free(skb);
 870                 return br_dev_queue_push_xmit(net, sk, skb);
 871         }
 872
 873         /* This is wrong! We should preserve the original fragment
 874          * boundaries by preserving frag_list rather than refragmenting.
 875          */
 876         if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) &&
 877             skb->protocol == htons(ETH_P_IP)) {
 878                 struct brnf_frag_data *data;
 879
 880                 if (br_validate_ipv4(net, skb))
 881                         goto drop;
 882
 883                 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
 884
 885                 data = this_cpu_ptr(&brnf_frag_data_storage);
 886
 887                 if (skb_vlan_tag_present(skb)) {
 888                         data->vlan_tci = skb->vlan_tci;
 889                         data->vlan_proto = skb->vlan_proto;
 890                 } else {
 891                         data->vlan_proto = 0;
 892                 }
 893
 894                 data->encap_size = nf_bridge_encap_header_len(skb);
 895                 data->size = ETH_HLEN + data->encap_size;
 896
 897                 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
 898                                                  data->size);
 899
 900                 return br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit);
 901         }
 902         if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) &&
 903             skb->protocol == htons(ETH_P_IPV6)) {
 904                 const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
 905                 struct brnf_frag_data *data;
 906
 907                 if (br_validate_ipv6(net, skb))
 908                         goto drop;
 909
 910                 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
 911
 912                 data = this_cpu_ptr(&brnf_frag_data_storage);
 913                 data->encap_size = nf_bridge_encap_header_len(skb);
 914                 data->size = ETH_HLEN + data->encap_size;
 915
 916                 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
 917                                                  data->size);
 918
 919                 if (v6ops)
 920                         return v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit);
 921
 922                 kfree_skb(skb);
 923                 return -EMSGSIZE;
 924         }
 925         nf_bridge_info_free(skb);
 926         return br_dev_queue_push_xmit(net, sk, skb);
 927  drop:
 928         kfree_skb(skb);
 929         return 0;
 930 }
 931
 932 /* PF_BRIDGE/POST_ROUTING ********************************************/
 933 static unsigned int br_nf_post_routing(void *priv,
 934                                        struct sk_buff *skb,
 935                                        const struct nf_hook_state *state)
 936 {
 937         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 938         struct net_device *realoutdev = bridge_parent(skb->dev);
 939         u_int8_t pf;
 940
 941         /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
 942          * on a bridge, but was delivered locally and is now being routed:
 943          *
 944          * POST_ROUTING was already invoked from the ip stack.
 945          */
 946         if (!nf_bridge || !nf_bridge->physoutdev)
 947                 return NF_ACCEPT;
 948
 949         if (!realoutdev)
 950                 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
 951
 952         if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
 953             is_pppoe_ip(skb, state->net))
 954                 pf = NFPROTO_IPV4;
 955         else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
 956                  is_pppoe_ipv6(skb, state->net))
 957                 pf = NFPROTO_IPV6;
 958         else
 959                 return NF_ACCEPT;
 960
 961         if (skb->pkt_type == PACKET_OTHERHOST) {
 962                 skb->pkt_type = PACKET_HOST;
 963                 nf_bridge->pkt_otherhost = true;
 964         }
 965
 966         nf_bridge_pull_encap_header(skb);
 967         if (pf == NFPROTO_IPV4)
 968                 skb->protocol = htons(ETH_P_IP);
 969         else
 970                 skb->protocol = htons(ETH_P_IPV6);
 971
 972         NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
 973                 NULL, realoutdev,
 974                 br_nf_dev_queue_xmit);
 975
 976         return NF_STOLEN;
 977 }
 978
 979 /* IP/SABOTAGE *****************************************************/
 980 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
 981  * for the second time. */
 982 static unsigned int ip_sabotage_in(void *priv,
 983                                    struct sk_buff *skb,
 984                                    const struct nf_hook_state *state)
 985 {
 986         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 987
 988         if (nf_bridge) {
 989                 if (nf_bridge->sabotage_in_done)
 990                         return NF_ACCEPT;
 991
 992                 if (!nf_bridge->in_prerouting &&
 993                     !netif_is_l3_master(skb->dev) &&
 994                     !netif_is_l3_slave(skb->dev)) {
 995                         nf_bridge->sabotage_in_done = 1;
 996                         state->okfn(state->net, state->sk, skb);
 997                         return NF_STOLEN;
 998                 }
 999         }
1000
1001         return NF_ACCEPT;
1002 }
1003
1004 /* This is called when br_netfilter has called into iptables/netfilter,
1005  * and DNAT has taken place on a bridge-forwarded packet.
1006  *
1007  * neigh->output has created a new MAC header, with local br0 MAC
1008  * as saddr.
1009  *
1010  * This restores the original MAC saddr of the bridged packet
1011  * before invoking bridge forward logic to transmit the packet.
1012  */
1013 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
1014 {
1015         struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1016         struct net_device *br_indev;
1017
1018         br_indev = nf_bridge_get_physindev(skb, dev_net(skb->dev));
1019         if (!br_indev) {
1020                 kfree_skb(skb);
1021                 return;
1022         }
1023
1024         skb_pull(skb, ETH_HLEN);
1025         nf_bridge->bridged_dnat = 0;
1026
1027         BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
1028
1029         skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
1030                                        nf_bridge->neigh_header,
1031                                        ETH_HLEN - ETH_ALEN);
1032         skb->dev = br_indev;
1033
1034         nf_bridge->physoutdev = NULL;
1035         br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
1036 }
1037
1038 static int br_nf_dev_xmit(struct sk_buff *skb)
1039 {
1040         const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1041
1042         if (nf_bridge && nf_bridge->bridged_dnat) {
1043                 br_nf_pre_routing_finish_bridge_slow(skb);
1044                 return 1;
1045         }
1046         return 0;
1047 }
1048
1049 static const struct nf_br_ops br_ops = {
1050         .br_dev_xmit_hook =     br_nf_dev_xmit,
1051 };
1052
1053 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
1054  * br_dev_queue_push_xmit is called afterwards */
1055 static const struct nf_hook_ops br_nf_ops[] = {
1056         {
1057                 .hook = br_nf_pre_routing,
1058                 .pf = NFPROTO_BRIDGE,
1059                 .hooknum = NF_BR_PRE_ROUTING,
1060                 .priority = NF_BR_PRI_BRNF,
1061         },
1062 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1063         {
1064                 .hook = br_nf_local_in,
1065                 .pf = NFPROTO_BRIDGE,
1066                 .hooknum = NF_BR_LOCAL_IN,
1067                 .priority = NF_BR_PRI_LAST,
1068         },
1069 #endif
1070         {
1071                 .hook = br_nf_forward,
1072                 .pf = NFPROTO_BRIDGE,
1073                 .hooknum = NF_BR_FORWARD,
1074                 .priority = NF_BR_PRI_BRNF,
1075         },
1076         {
1077                 .hook = br_nf_post_routing,
1078                 .pf = NFPROTO_BRIDGE,
1079                 .hooknum = NF_BR_POST_ROUTING,
1080                 .priority = NF_BR_PRI_LAST,
1081         },
1082         {
1083                 .hook = ip_sabotage_in,
1084                 .pf = NFPROTO_IPV4,
1085                 .hooknum = NF_INET_PRE_ROUTING,
1086                 .priority = NF_IP_PRI_FIRST,
1087         },
1088         {
1089                 .hook = ip_sabotage_in,
1090                 .pf = NFPROTO_IPV6,
1091                 .hooknum = NF_INET_PRE_ROUTING,
1092                 .priority = NF_IP6_PRI_FIRST,
1093         },
1094 };
1095
1096 static int brnf_device_event(struct notifier_block *unused, unsigned long event,
1097                              void *ptr)
1098 {
1099         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1100         struct brnf_net *brnet;
1101         struct net *net;
1102         int ret;
1103
1104         if (event != NETDEV_REGISTER || !netif_is_bridge_master(dev))
1105                 return NOTIFY_DONE;
1106
1107         ASSERT_RTNL();
1108
1109         net = dev_net(dev);
1110         brnet = net_generic(net, brnf_net_id);
1111         if (brnet->enabled)
1112                 return NOTIFY_OK;
1113
1114         ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1115         if (ret)
1116                 return NOTIFY_BAD;
1117
1118         brnet->enabled = true;
1119         return NOTIFY_OK;
1120 }
1121
1122 static struct notifier_block brnf_notifier __read_mostly = {
1123         .notifier_call = brnf_device_event,
1124 };
1125
1126 /* recursively invokes nf_hook_slow (again), skipping already-called
1127  * hooks (< NF_BR_PRI_BRNF).
1128  *
1129  * Called with rcu read lock held.
1130  */
1131 int br_nf_hook_thresh(unsigned int hook, struct net *net,
1132                       struct sock *sk, struct sk_buff *skb,
1133                       struct net_device *indev,
1134                       struct net_device *outdev,
1135                       int (*okfn)(struct net *, struct sock *,
1136                                   struct sk_buff *))
1137 {
1138         const struct nf_hook_entries *e;
1139         struct nf_hook_state state;
1140         struct nf_hook_ops **ops;
1141         unsigned int i;
1142         int ret;
1143
1144         e = rcu_dereference(net->nf.hooks_bridge[hook]);
1145         if (!e)
1146                 return okfn(net, sk, skb);
1147
1148         ops = nf_hook_entries_get_hook_ops(e);
1149         for (i = 0; i < e->num_hook_entries; i++) {
1150                 /* These hooks have already been called */
1151                 if (ops[i]->priority < NF_BR_PRI_BRNF)
1152                         continue;
1153
1154                 /* These hooks have not been called yet, run them. */
1155                 if (ops[i]->priority > NF_BR_PRI_BRNF)
1156                         break;
1157
1158                 /* take a closer look at NF_BR_PRI_BRNF. */
1159                 if (ops[i]->hook == br_nf_pre_routing) {
1160                         /* This hook diverted the skb to this function,
1161                          * hooks after this have not been run yet.
1162                          */
1163                         i++;
1164                         break;
1165                 }
1166         }
1167
1168         nf_hook_state_init(&state, hook, NFPROTO_BRIDGE, indev, outdev,
1169                            sk, net, okfn);
1170
1171         ret = nf_hook_slow(skb, &state, e, i);
1172         if (ret == 1)
1173                 ret = okfn(net, sk, skb);
1174
1175         return ret;
1176 }
1177
1178 #ifdef CONFIG_SYSCTL
1179 static
1180 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
1181                             void *buffer, size_t *lenp, loff_t *ppos)
1182 {
1183         int ret;
1184
1185         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1186
1187         if (write && *(int *)(ctl->data))
1188                 *(int *)(ctl->data) = 1;
1189         return ret;
1190 }
1191
1192 static struct ctl_table brnf_table[] = {
1193         {
1194                 .procname       = "bridge-nf-call-arptables",
1195                 .maxlen         = sizeof(int),
1196                 .mode           = 0644,
1197                 .proc_handler   = brnf_sysctl_call_tables,
1198         },
1199         {
1200                 .procname       = "bridge-nf-call-iptables",
1201                 .maxlen         = sizeof(int),
1202                 .mode           = 0644,
1203                 .proc_handler   = brnf_sysctl_call_tables,
1204         },
1205         {
1206                 .procname       = "bridge-nf-call-ip6tables",
1207                 .maxlen         = sizeof(int),
1208                 .mode           = 0644,
1209                 .proc_handler   = brnf_sysctl_call_tables,
1210         },
1211         {
1212                 .procname       = "bridge-nf-filter-vlan-tagged",
1213                 .maxlen         = sizeof(int),
1214                 .mode           = 0644,
1215                 .proc_handler   = brnf_sysctl_call_tables,
1216         },
1217         {
1218                 .procname       = "bridge-nf-filter-pppoe-tagged",
1219                 .maxlen         = sizeof(int),
1220                 .mode           = 0644,
1221                 .proc_handler   = brnf_sysctl_call_tables,
1222         },
1223         {
1224                 .procname       = "bridge-nf-pass-vlan-input-dev",
1225                 .maxlen         = sizeof(int),
1226                 .mode           = 0644,
1227                 .proc_handler   = brnf_sysctl_call_tables,
1228         },
1229 };
1230
1231 static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
1232 {
1233         brnf->call_iptables = 1;
1234         brnf->call_ip6tables = 1;
1235         brnf->call_arptables = 1;
1236         brnf->filter_vlan_tagged = 0;
1237         brnf->filter_pppoe_tagged = 0;
1238         brnf->pass_vlan_indev = 0;
1239 }
1240
1241 static int br_netfilter_sysctl_init_net(struct net *net)
1242 {
1243         struct ctl_table *table = brnf_table;
1244         struct brnf_net *brnet;
1245
1246         if (!net_eq(net, &init_net)) {
1247                 table = kmemdup(table, sizeof(brnf_table), GFP_KERNEL);
1248                 if (!table)
1249                         return -ENOMEM;
1250         }
1251
1252         brnet = net_generic(net, brnf_net_id);
1253         table[0].data = &brnet->call_arptables;
1254         table[1].data = &brnet->call_iptables;
1255         table[2].data = &brnet->call_ip6tables;
1256         table[3].data = &brnet->filter_vlan_tagged;
1257         table[4].data = &brnet->filter_pppoe_tagged;
1258         table[5].data = &brnet->pass_vlan_indev;
1259
1260         br_netfilter_sysctl_default(brnet);
1261
1262         brnet->ctl_hdr = register_net_sysctl_sz(net, "net/bridge", table,
1263                                                 ARRAY_SIZE(brnf_table));
1264         if (!brnet->ctl_hdr) {
1265                 if (!net_eq(net, &init_net))
1266                         kfree(table);
1267
1268                 return -ENOMEM;
1269         }
1270
1271         return 0;
1272 }
1273
1274 static void br_netfilter_sysctl_exit_net(struct net *net,
1275                                          struct brnf_net *brnet)
1276 {
1277         const struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
1278
1279         unregister_net_sysctl_table(brnet->ctl_hdr);
1280         if (!net_eq(net, &init_net))
1281                 kfree(table);
1282 }
1283
1284 static int __net_init brnf_init_net(struct net *net)
1285 {
1286         return br_netfilter_sysctl_init_net(net);
1287 }
1288 #endif
1289
1290 static void __net_exit brnf_exit_net(struct net *net)
1291 {
1292         struct brnf_net *brnet;
1293
1294         brnet = net_generic(net, brnf_net_id);
1295         if (brnet->enabled) {
1296                 nf_unregister_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1297                 brnet->enabled = false;
1298         }
1299
1300 #ifdef CONFIG_SYSCTL
1301         br_netfilter_sysctl_exit_net(net, brnet);
1302 #endif
1303 }
1304
1305 static struct pernet_operations brnf_net_ops __read_mostly = {
1306 #ifdef CONFIG_SYSCTL
1307         .init = brnf_init_net,
1308 #endif
1309         .exit = brnf_exit_net,
1310         .id   = &brnf_net_id,
1311         .size = sizeof(struct brnf_net),
1312 };
1313
1314 static int __init br_netfilter_init(void)
1315 {
1316         int ret;
1317
1318         ret = register_pernet_subsys(&brnf_net_ops);
1319         if (ret < 0)
1320                 return ret;
1321
1322         ret = register_netdevice_notifier(&brnf_notifier);
1323         if (ret < 0) {
1324                 unregister_pernet_subsys(&brnf_net_ops);
1325                 return ret;
1326         }
1327
1328         RCU_INIT_POINTER(nf_br_ops, &br_ops);
1329         printk(KERN_NOTICE "Bridge firewalling registered\n");
1330         return 0;
1331 }
1332
1333 static void __exit br_netfilter_fini(void)
1334 {
1335         RCU_INIT_POINTER(nf_br_ops, NULL);
1336         unregister_netdevice_notifier(&brnf_notifier);
1337         unregister_pernet_subsys(&brnf_net_ops);
1338 }
1339
1340 module_init(br_netfilter_init);
1341 module_exit(br_netfilter_fini);
1342
1343 MODULE_LICENSE("GPL");
1344 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1345 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1346 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");