1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Handle bridge arp/nd proxy/suppress 4 * 5 * Copyright (C) 2017 Cumulus Networks 6 * Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com> 7 * 8 * Authors: 9 * Roopa Prabhu <roopa@cumulusnetworks.com> 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/netdevice.h> 14 #include <linux/etherdevice.h> 15 #include <linux/neighbour.h> 16 #include <net/arp.h> 17 #include <linux/if_vlan.h> 18 #include <linux/inetdevice.h> 19 #include <net/addrconf.h> 20 #include <net/ipv6_stubs.h> 21 #if IS_ENABLED(CONFIG_IPV6) 22 #include <net/ip6_checksum.h> 23 #endif 24 25 #include "br_private.h" 26 27 void br_recalculate_neigh_suppress_enabled(struct net_bridge *br) 28 { 29 struct net_bridge_port *p; 30 bool neigh_suppress = false; 31 32 list_for_each_entry(p, &br->port_list, list) { 33 if (p->flags & BR_NEIGH_SUPPRESS) { 34 neigh_suppress = true; 35 break; 36 } 37 } 38 39 br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress); 40 } 41 42 #if IS_ENABLED(CONFIG_INET) 43 static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p, 44 struct net_device *dev, __be32 dest_ip, __be32 src_ip, 45 const unsigned char *dest_hw, 46 const unsigned char *src_hw, 47 const unsigned char *target_hw, 48 __be16 vlan_proto, u16 vlan_tci) 49 { 50 struct net_bridge_vlan_group *vg; 51 struct sk_buff *skb; 52 u16 pvid; 53 54 netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n", 55 dev->name, &dest_ip, dest_hw, &src_ip, src_hw); 56 57 if (!vlan_tci) { 58 arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip, 59 dest_hw, src_hw, target_hw); 60 return; 61 } 62 63 skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip, 64 dest_hw, src_hw, target_hw); 65 if (!skb) 66 return; 67 68 if (p) 69 vg = nbp_vlan_group_rcu(p); 70 else 71 vg = br_vlan_group_rcu(br); 72 pvid = br_get_pvid(vg); 73 if (pvid == (vlan_tci & VLAN_VID_MASK)) 74 vlan_tci = 0; 75 76 if (vlan_tci) 77 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); 78 79 if (p) { 80 arp_xmit(skb); 81 } else { 82 skb_reset_mac_header(skb); 83 __skb_pull(skb, skb_network_offset(skb)); 84 skb->ip_summed = CHECKSUM_UNNECESSARY; 85 skb->pkt_type = PACKET_HOST; 86 87 netif_rx(skb); 88 } 89 } 90 91 static int br_chk_addr_ip(struct net_device *dev, 92 struct netdev_nested_priv *priv) 93 { 94 __be32 ip = *(__be32 *)priv->data; 95 struct in_device *in_dev; 96 __be32 addr = 0; 97 98 in_dev = __in_dev_get_rcu(dev); 99 if (in_dev) 100 addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip, 101 RT_SCOPE_HOST); 102 103 if (addr == ip) 104 return 1; 105 106 return 0; 107 } 108 109 static bool br_is_local_ip(struct net_device *dev, __be32 ip) 110 { 111 struct netdev_nested_priv priv = { 112 .data = (void *)&ip, 113 }; 114 115 if (br_chk_addr_ip(dev, &priv)) 116 return true; 117 118 /* check if ip is configured on upper dev */ 119 if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &priv)) 120 return true; 121 122 return false; 123 } 124 125 void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br, 126 u16 vid, struct net_bridge_port *p) 127 { 128 struct net_device *dev = br->dev; 129 struct net_device *vlandev = dev; 130 struct neighbour *n; 131 struct arphdr *parp; 132 u8 *arpptr, *sha; 133 __be32 sip, tip; 134 135 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0; 136 137 if ((dev->flags & IFF_NOARP) || 138 !pskb_may_pull(skb, arp_hdr_len(dev))) 139 return; 140 141 parp = arp_hdr(skb); 142 143 if (parp->ar_pro != htons(ETH_P_IP) || 144 parp->ar_hln != dev->addr_len || 145 parp->ar_pln != 4) 146 return; 147 148 arpptr = (u8 *)parp + sizeof(struct arphdr); 149 sha = arpptr; 150 arpptr += dev->addr_len; /* sha */ 151 memcpy(&sip, arpptr, sizeof(sip)); 152 arpptr += sizeof(sip); 153 arpptr += dev->addr_len; /* tha */ 154 memcpy(&tip, arpptr, sizeof(tip)); 155 156 if (ipv4_is_loopback(tip) || 157 ipv4_is_multicast(tip)) 158 return; 159 160 if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) { 161 if (p && (p->flags & BR_NEIGH_SUPPRESS)) 162 return; 163 if (parp->ar_op != htons(ARPOP_RREQUEST) && 164 parp->ar_op != htons(ARPOP_RREPLY) && 165 (ipv4_is_zeronet(sip) || sip == tip)) { 166 /* prevent flooding to neigh suppress ports */ 167 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 168 return; 169 } 170 } 171 172 if (parp->ar_op != htons(ARPOP_REQUEST)) 173 return; 174 175 if (vid != 0) { 176 vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto, 177 vid); 178 if (!vlandev) 179 return; 180 } 181 182 if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) && 183 br_is_local_ip(vlandev, tip)) { 184 /* its our local ip, so don't proxy reply 185 * and don't forward to neigh suppress ports 186 */ 187 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 188 return; 189 } 190 191 n = neigh_lookup(&arp_tbl, &tip, vlandev); 192 if (n) { 193 struct net_bridge_fdb_entry *f; 194 195 if (!(n->nud_state & NUD_VALID)) { 196 neigh_release(n); 197 return; 198 } 199 200 f = br_fdb_find_rcu(br, n->ha, vid); 201 if (f) { 202 bool replied = false; 203 204 if ((p && (p->flags & BR_PROXYARP)) || 205 (f->dst && (f->dst->flags & (BR_PROXYARP_WIFI | 206 BR_NEIGH_SUPPRESS)))) { 207 if (!vid) 208 br_arp_send(br, p, skb->dev, sip, tip, 209 sha, n->ha, sha, 0, 0); 210 else 211 br_arp_send(br, p, skb->dev, sip, tip, 212 sha, n->ha, sha, 213 skb->vlan_proto, 214 skb_vlan_tag_get(skb)); 215 replied = true; 216 } 217 218 /* If we have replied or as long as we know the 219 * mac, indicate to arp replied 220 */ 221 if (replied || 222 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) 223 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 224 } 225 226 neigh_release(n); 227 } 228 } 229 #endif 230 231 #if IS_ENABLED(CONFIG_IPV6) 232 struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *msg) 233 { 234 struct nd_msg *m; 235 236 m = skb_header_pointer(skb, skb_network_offset(skb) + 237 sizeof(struct ipv6hdr), sizeof(*msg), msg); 238 if (!m) 239 return NULL; 240 241 if (m->icmph.icmp6_code != 0 || 242 (m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION && 243 m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT)) 244 return NULL; 245 246 return m; 247 } 248 249 static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p, 250 struct sk_buff *request, struct neighbour *n, 251 __be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns) 252 { 253 struct net_device *dev = request->dev; 254 struct net_bridge_vlan_group *vg; 255 struct sk_buff *reply; 256 struct nd_msg *na; 257 struct ipv6hdr *pip6; 258 int na_olen = 8; /* opt hdr + ETH_ALEN for target */ 259 int ns_olen; 260 int i, len; 261 u8 *daddr; 262 u16 pvid; 263 264 if (!dev) 265 return; 266 267 len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) + 268 sizeof(*na) + na_olen + dev->needed_tailroom; 269 270 reply = alloc_skb(len, GFP_ATOMIC); 271 if (!reply) 272 return; 273 274 reply->protocol = htons(ETH_P_IPV6); 275 reply->dev = dev; 276 skb_reserve(reply, LL_RESERVED_SPACE(dev)); 277 skb_push(reply, sizeof(struct ethhdr)); 278 skb_set_mac_header(reply, 0); 279 280 daddr = eth_hdr(request)->h_source; 281 282 /* Do we need option processing ? */ 283 ns_olen = request->len - (skb_network_offset(request) + 284 sizeof(struct ipv6hdr)) - sizeof(*ns); 285 for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) { 286 if (!ns->opt[i + 1]) { 287 kfree_skb(reply); 288 return; 289 } 290 if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { 291 daddr = ns->opt + i + sizeof(struct nd_opt_hdr); 292 break; 293 } 294 } 295 296 /* Ethernet header */ 297 ether_addr_copy(eth_hdr(reply)->h_dest, daddr); 298 ether_addr_copy(eth_hdr(reply)->h_source, n->ha); 299 eth_hdr(reply)->h_proto = htons(ETH_P_IPV6); 300 reply->protocol = htons(ETH_P_IPV6); 301 302 skb_pull(reply, sizeof(struct ethhdr)); 303 skb_set_network_header(reply, 0); 304 skb_put(reply, sizeof(struct ipv6hdr)); 305 306 /* IPv6 header */ 307 pip6 = ipv6_hdr(reply); 308 memset(pip6, 0, sizeof(struct ipv6hdr)); 309 pip6->version = 6; 310 pip6->priority = ipv6_hdr(request)->priority; 311 pip6->nexthdr = IPPROTO_ICMPV6; 312 pip6->hop_limit = 255; 313 pip6->daddr = ipv6_hdr(request)->saddr; 314 pip6->saddr = *(struct in6_addr *)n->primary_key; 315 316 skb_pull(reply, sizeof(struct ipv6hdr)); 317 skb_set_transport_header(reply, 0); 318 319 na = (struct nd_msg *)skb_put(reply, sizeof(*na) + na_olen); 320 321 /* Neighbor Advertisement */ 322 memset(na, 0, sizeof(*na) + na_olen); 323 na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT; 324 na->icmph.icmp6_router = (n->flags & NTF_ROUTER) ? 1 : 0; 325 na->icmph.icmp6_override = 1; 326 na->icmph.icmp6_solicited = 1; 327 na->target = ns->target; 328 ether_addr_copy(&na->opt[2], n->ha); 329 na->opt[0] = ND_OPT_TARGET_LL_ADDR; 330 na->opt[1] = na_olen >> 3; 331 332 na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr, 333 &pip6->daddr, 334 sizeof(*na) + na_olen, 335 IPPROTO_ICMPV6, 336 csum_partial(na, sizeof(*na) + na_olen, 0)); 337 338 pip6->payload_len = htons(sizeof(*na) + na_olen); 339 340 skb_push(reply, sizeof(struct ipv6hdr)); 341 skb_push(reply, sizeof(struct ethhdr)); 342 343 reply->ip_summed = CHECKSUM_UNNECESSARY; 344 345 if (p) 346 vg = nbp_vlan_group_rcu(p); 347 else 348 vg = br_vlan_group_rcu(br); 349 pvid = br_get_pvid(vg); 350 if (pvid == (vlan_tci & VLAN_VID_MASK)) 351 vlan_tci = 0; 352 353 if (vlan_tci) 354 __vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci); 355 356 netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n", 357 dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha); 358 359 if (p) { 360 dev_queue_xmit(reply); 361 } else { 362 skb_reset_mac_header(reply); 363 __skb_pull(reply, skb_network_offset(reply)); 364 reply->ip_summed = CHECKSUM_UNNECESSARY; 365 reply->pkt_type = PACKET_HOST; 366 367 netif_rx(reply); 368 } 369 } 370 371 static int br_chk_addr_ip6(struct net_device *dev, 372 struct netdev_nested_priv *priv) 373 { 374 struct in6_addr *addr = (struct in6_addr *)priv->data; 375 376 if (ipv6_chk_addr(dev_net(dev), addr, dev, 0)) 377 return 1; 378 379 return 0; 380 } 381 382 static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr) 383 384 { 385 struct netdev_nested_priv priv = { 386 .data = (void *)addr, 387 }; 388 389 if (br_chk_addr_ip6(dev, &priv)) 390 return true; 391 392 /* check if ip is configured on upper dev */ 393 if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, &priv)) 394 return true; 395 396 return false; 397 } 398 399 void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br, 400 u16 vid, struct net_bridge_port *p, struct nd_msg *msg) 401 { 402 struct net_device *dev = br->dev; 403 struct net_device *vlandev = NULL; 404 struct in6_addr *saddr, *daddr; 405 struct ipv6hdr *iphdr; 406 struct neighbour *n; 407 408 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0; 409 410 if (p && (p->flags & BR_NEIGH_SUPPRESS)) 411 return; 412 413 if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT && 414 !msg->icmph.icmp6_solicited) { 415 /* prevent flooding to neigh suppress ports */ 416 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 417 return; 418 } 419 420 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION) 421 return; 422 423 iphdr = ipv6_hdr(skb); 424 saddr = &iphdr->saddr; 425 daddr = &iphdr->daddr; 426 427 if (ipv6_addr_any(saddr) || !ipv6_addr_cmp(saddr, daddr)) { 428 /* prevent flooding to neigh suppress ports */ 429 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 430 return; 431 } 432 433 if (vid != 0) { 434 /* build neigh table lookup on the vlan device */ 435 vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto, 436 vid); 437 if (!vlandev) 438 return; 439 } else { 440 vlandev = dev; 441 } 442 443 if (br_is_local_ip6(vlandev, &msg->target)) { 444 /* its our own ip, so don't proxy reply 445 * and don't forward to arp suppress ports 446 */ 447 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 448 return; 449 } 450 451 n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev); 452 if (n) { 453 struct net_bridge_fdb_entry *f; 454 455 if (!(n->nud_state & NUD_VALID)) { 456 neigh_release(n); 457 return; 458 } 459 460 f = br_fdb_find_rcu(br, n->ha, vid); 461 if (f) { 462 bool replied = false; 463 464 if (f->dst && (f->dst->flags & BR_NEIGH_SUPPRESS)) { 465 if (vid != 0) 466 br_nd_send(br, p, skb, n, 467 skb->vlan_proto, 468 skb_vlan_tag_get(skb), msg); 469 else 470 br_nd_send(br, p, skb, n, 0, 0, msg); 471 replied = true; 472 } 473 474 /* If we have replied or as long as we know the 475 * mac, indicate to NEIGH_SUPPRESS ports that we 476 * have replied 477 */ 478 if (replied || 479 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) 480 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1; 481 } 482 neigh_release(n); 483 } 484 } 485 #endif 486