| 1 | /* |
| 2 | * Internet Control Message Protocol (ICMPv6) |
| 3 | * Linux INET6 implementation |
| 4 | * |
| 5 | * Authors: |
| 6 | * Pedro Roque <roque@di.fc.ul.pt> |
| 7 | * |
| 8 | * Based on net/ipv4/icmp.c |
| 9 | * |
| 10 | * RFC 1885 |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or |
| 13 | * modify it under the terms of the GNU General Public License |
| 14 | * as published by the Free Software Foundation; either version |
| 15 | * 2 of the License, or (at your option) any later version. |
| 16 | */ |
| 17 | |
| 18 | /* |
| 19 | * Changes: |
| 20 | * |
| 21 | * Andi Kleen : exception handling |
| 22 | * Andi Kleen add rate limits. never reply to a icmp. |
| 23 | * add more length checks and other fixes. |
| 24 | * yoshfuji : ensure to sent parameter problem for |
| 25 | * fragments. |
| 26 | * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit. |
| 27 | * Randy Dunlap and |
| 28 | * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support |
| 29 | * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data |
| 30 | */ |
| 31 | |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/errno.h> |
| 34 | #include <linux/types.h> |
| 35 | #include <linux/socket.h> |
| 36 | #include <linux/in.h> |
| 37 | #include <linux/kernel.h> |
| 38 | #include <linux/sockios.h> |
| 39 | #include <linux/net.h> |
| 40 | #include <linux/skbuff.h> |
| 41 | #include <linux/init.h> |
| 42 | #include <linux/netfilter.h> |
| 43 | #include <linux/slab.h> |
| 44 | |
| 45 | #ifdef CONFIG_SYSCTL |
| 46 | #include <linux/sysctl.h> |
| 47 | #endif |
| 48 | |
| 49 | #include <linux/inet.h> |
| 50 | #include <linux/netdevice.h> |
| 51 | #include <linux/icmpv6.h> |
| 52 | |
| 53 | #include <net/ip.h> |
| 54 | #include <net/sock.h> |
| 55 | |
| 56 | #include <net/ipv6.h> |
| 57 | #include <net/ip6_checksum.h> |
| 58 | #include <net/protocol.h> |
| 59 | #include <net/raw.h> |
| 60 | #include <net/rawv6.h> |
| 61 | #include <net/transp_v6.h> |
| 62 | #include <net/ip6_route.h> |
| 63 | #include <net/addrconf.h> |
| 64 | #include <net/icmp.h> |
| 65 | #include <net/xfrm.h> |
| 66 | #include <net/inet_common.h> |
| 67 | |
| 68 | #include <asm/uaccess.h> |
| 69 | #include <asm/system.h> |
| 70 | |
| 71 | /* |
| 72 | * The ICMP socket(s). This is the most convenient way to flow control |
| 73 | * our ICMP output as well as maintain a clean interface throughout |
| 74 | * all layers. All Socketless IP sends will soon be gone. |
| 75 | * |
| 76 | * On SMP we have one ICMP socket per-cpu. |
| 77 | */ |
| 78 | static inline struct sock *icmpv6_sk(struct net *net) |
| 79 | { |
| 80 | return net->ipv6.icmp_sk[smp_processor_id()]; |
| 81 | } |
| 82 | |
| 83 | static int icmpv6_rcv(struct sk_buff *skb); |
| 84 | |
| 85 | static const struct inet6_protocol icmpv6_protocol = { |
| 86 | .handler = icmpv6_rcv, |
| 87 | .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, |
| 88 | }; |
| 89 | |
| 90 | static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) |
| 91 | { |
| 92 | struct sock *sk; |
| 93 | |
| 94 | local_bh_disable(); |
| 95 | |
| 96 | sk = icmpv6_sk(net); |
| 97 | if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { |
| 98 | /* This can happen if the output path (f.e. SIT or |
| 99 | * ip6ip6 tunnel) signals dst_link_failure() for an |
| 100 | * outgoing ICMP6 packet. |
| 101 | */ |
| 102 | local_bh_enable(); |
| 103 | return NULL; |
| 104 | } |
| 105 | return sk; |
| 106 | } |
| 107 | |
| 108 | static __inline__ void icmpv6_xmit_unlock(struct sock *sk) |
| 109 | { |
| 110 | spin_unlock_bh(&sk->sk_lock.slock); |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * Slightly more convenient version of icmpv6_send. |
| 115 | */ |
| 116 | void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) |
| 117 | { |
| 118 | icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); |
| 119 | kfree_skb(skb); |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Figure out, may we reply to this packet with icmp error. |
| 124 | * |
| 125 | * We do not reply, if: |
| 126 | * - it was icmp error message. |
| 127 | * - it is truncated, so that it is known, that protocol is ICMPV6 |
| 128 | * (i.e. in the middle of some exthdr) |
| 129 | * |
| 130 | * --ANK (980726) |
| 131 | */ |
| 132 | |
| 133 | static int is_ineligible(struct sk_buff *skb) |
| 134 | { |
| 135 | int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; |
| 136 | int len = skb->len - ptr; |
| 137 | __u8 nexthdr = ipv6_hdr(skb)->nexthdr; |
| 138 | |
| 139 | if (len < 0) |
| 140 | return 1; |
| 141 | |
| 142 | ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr); |
| 143 | if (ptr < 0) |
| 144 | return 0; |
| 145 | if (nexthdr == IPPROTO_ICMPV6) { |
| 146 | u8 _type, *tp; |
| 147 | tp = skb_header_pointer(skb, |
| 148 | ptr+offsetof(struct icmp6hdr, icmp6_type), |
| 149 | sizeof(_type), &_type); |
| 150 | if (tp == NULL || |
| 151 | !(*tp & ICMPV6_INFOMSG_MASK)) |
| 152 | return 1; |
| 153 | } |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * Check the ICMP output rate limit |
| 159 | */ |
| 160 | static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type, |
| 161 | struct flowi6 *fl6) |
| 162 | { |
| 163 | struct dst_entry *dst; |
| 164 | struct net *net = sock_net(sk); |
| 165 | bool res = false; |
| 166 | |
| 167 | /* Informational messages are not limited. */ |
| 168 | if (type & ICMPV6_INFOMSG_MASK) |
| 169 | return true; |
| 170 | |
| 171 | /* Do not limit pmtu discovery, it would break it. */ |
| 172 | if (type == ICMPV6_PKT_TOOBIG) |
| 173 | return true; |
| 174 | |
| 175 | /* |
| 176 | * Look up the output route. |
| 177 | * XXX: perhaps the expire for routing entries cloned by |
| 178 | * this lookup should be more aggressive (not longer than timeout). |
| 179 | */ |
| 180 | dst = ip6_route_output(net, sk, fl6); |
| 181 | if (dst->error) { |
| 182 | IP6_INC_STATS(net, ip6_dst_idev(dst), |
| 183 | IPSTATS_MIB_OUTNOROUTES); |
| 184 | } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { |
| 185 | res = true; |
| 186 | } else { |
| 187 | struct rt6_info *rt = (struct rt6_info *)dst; |
| 188 | int tmo = net->ipv6.sysctl.icmpv6_time; |
| 189 | |
| 190 | /* Give more bandwidth to wider prefixes. */ |
| 191 | if (rt->rt6i_dst.plen < 128) |
| 192 | tmo >>= ((128 - rt->rt6i_dst.plen)>>5); |
| 193 | |
| 194 | if (!rt->rt6i_peer) |
| 195 | rt6_bind_peer(rt, 1); |
| 196 | res = inet_peer_xrlim_allow(rt->rt6i_peer, tmo); |
| 197 | } |
| 198 | dst_release(dst); |
| 199 | return res; |
| 200 | } |
| 201 | |
| 202 | /* |
| 203 | * an inline helper for the "simple" if statement below |
| 204 | * checks if parameter problem report is caused by an |
| 205 | * unrecognized IPv6 option that has the Option Type |
| 206 | * highest-order two bits set to 10 |
| 207 | */ |
| 208 | |
| 209 | static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset) |
| 210 | { |
| 211 | u8 _optval, *op; |
| 212 | |
| 213 | offset += skb_network_offset(skb); |
| 214 | op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); |
| 215 | if (op == NULL) |
| 216 | return 1; |
| 217 | return (*op & 0xC0) == 0x80; |
| 218 | } |
| 219 | |
| 220 | static int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len) |
| 221 | { |
| 222 | struct sk_buff *skb; |
| 223 | struct icmp6hdr *icmp6h; |
| 224 | int err = 0; |
| 225 | |
| 226 | if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) |
| 227 | goto out; |
| 228 | |
| 229 | icmp6h = icmp6_hdr(skb); |
| 230 | memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); |
| 231 | icmp6h->icmp6_cksum = 0; |
| 232 | |
| 233 | if (skb_queue_len(&sk->sk_write_queue) == 1) { |
| 234 | skb->csum = csum_partial(icmp6h, |
| 235 | sizeof(struct icmp6hdr), skb->csum); |
| 236 | icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, |
| 237 | &fl6->daddr, |
| 238 | len, fl6->flowi6_proto, |
| 239 | skb->csum); |
| 240 | } else { |
| 241 | __wsum tmp_csum = 0; |
| 242 | |
| 243 | skb_queue_walk(&sk->sk_write_queue, skb) { |
| 244 | tmp_csum = csum_add(tmp_csum, skb->csum); |
| 245 | } |
| 246 | |
| 247 | tmp_csum = csum_partial(icmp6h, |
| 248 | sizeof(struct icmp6hdr), tmp_csum); |
| 249 | icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, |
| 250 | &fl6->daddr, |
| 251 | len, fl6->flowi6_proto, |
| 252 | tmp_csum); |
| 253 | } |
| 254 | ip6_push_pending_frames(sk); |
| 255 | out: |
| 256 | return err; |
| 257 | } |
| 258 | |
| 259 | struct icmpv6_msg { |
| 260 | struct sk_buff *skb; |
| 261 | int offset; |
| 262 | uint8_t type; |
| 263 | }; |
| 264 | |
| 265 | static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) |
| 266 | { |
| 267 | struct icmpv6_msg *msg = (struct icmpv6_msg *) from; |
| 268 | struct sk_buff *org_skb = msg->skb; |
| 269 | __wsum csum = 0; |
| 270 | |
| 271 | csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, |
| 272 | to, len, csum); |
| 273 | skb->csum = csum_block_add(skb->csum, csum, odd); |
| 274 | if (!(msg->type & ICMPV6_INFOMSG_MASK)) |
| 275 | nf_ct_attach(skb, org_skb); |
| 276 | return 0; |
| 277 | } |
| 278 | |
| 279 | #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE) |
| 280 | static void mip6_addr_swap(struct sk_buff *skb) |
| 281 | { |
| 282 | struct ipv6hdr *iph = ipv6_hdr(skb); |
| 283 | struct inet6_skb_parm *opt = IP6CB(skb); |
| 284 | struct ipv6_destopt_hao *hao; |
| 285 | struct in6_addr tmp; |
| 286 | int off; |
| 287 | |
| 288 | if (opt->dsthao) { |
| 289 | off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); |
| 290 | if (likely(off >= 0)) { |
| 291 | hao = (struct ipv6_destopt_hao *) |
| 292 | (skb_network_header(skb) + off); |
| 293 | tmp = iph->saddr; |
| 294 | iph->saddr = hao->addr; |
| 295 | hao->addr = tmp; |
| 296 | } |
| 297 | } |
| 298 | } |
| 299 | #else |
| 300 | static inline void mip6_addr_swap(struct sk_buff *skb) {} |
| 301 | #endif |
| 302 | |
| 303 | static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb, |
| 304 | struct sock *sk, struct flowi6 *fl6) |
| 305 | { |
| 306 | struct dst_entry *dst, *dst2; |
| 307 | struct flowi6 fl2; |
| 308 | int err; |
| 309 | |
| 310 | err = ip6_dst_lookup(sk, &dst, fl6); |
| 311 | if (err) |
| 312 | return ERR_PTR(err); |
| 313 | |
| 314 | /* |
| 315 | * We won't send icmp if the destination is known |
| 316 | * anycast. |
| 317 | */ |
| 318 | if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) { |
| 319 | LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n"); |
| 320 | dst_release(dst); |
| 321 | return ERR_PTR(-EINVAL); |
| 322 | } |
| 323 | |
| 324 | /* No need to clone since we're just using its address. */ |
| 325 | dst2 = dst; |
| 326 | |
| 327 | dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); |
| 328 | if (!IS_ERR(dst)) { |
| 329 | if (dst != dst2) |
| 330 | return dst; |
| 331 | } else { |
| 332 | if (PTR_ERR(dst) == -EPERM) |
| 333 | dst = NULL; |
| 334 | else |
| 335 | return dst; |
| 336 | } |
| 337 | |
| 338 | err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); |
| 339 | if (err) |
| 340 | goto relookup_failed; |
| 341 | |
| 342 | err = ip6_dst_lookup(sk, &dst2, &fl2); |
| 343 | if (err) |
| 344 | goto relookup_failed; |
| 345 | |
| 346 | dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); |
| 347 | if (!IS_ERR(dst2)) { |
| 348 | dst_release(dst); |
| 349 | dst = dst2; |
| 350 | } else { |
| 351 | err = PTR_ERR(dst2); |
| 352 | if (err == -EPERM) { |
| 353 | dst_release(dst); |
| 354 | return dst2; |
| 355 | } else |
| 356 | goto relookup_failed; |
| 357 | } |
| 358 | |
| 359 | relookup_failed: |
| 360 | if (dst) |
| 361 | return dst; |
| 362 | return ERR_PTR(err); |
| 363 | } |
| 364 | |
| 365 | /* |
| 366 | * Send an ICMP message in response to a packet in error |
| 367 | */ |
| 368 | void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) |
| 369 | { |
| 370 | struct net *net = dev_net(skb->dev); |
| 371 | struct inet6_dev *idev = NULL; |
| 372 | struct ipv6hdr *hdr = ipv6_hdr(skb); |
| 373 | struct sock *sk; |
| 374 | struct ipv6_pinfo *np; |
| 375 | const struct in6_addr *saddr = NULL; |
| 376 | struct dst_entry *dst; |
| 377 | struct icmp6hdr tmp_hdr; |
| 378 | struct flowi6 fl6; |
| 379 | struct icmpv6_msg msg; |
| 380 | int iif = 0; |
| 381 | int addr_type = 0; |
| 382 | int len; |
| 383 | int hlimit; |
| 384 | int err = 0; |
| 385 | |
| 386 | if ((u8 *)hdr < skb->head || |
| 387 | (skb->network_header + sizeof(*hdr)) > skb->tail) |
| 388 | return; |
| 389 | |
| 390 | /* |
| 391 | * Make sure we respect the rules |
| 392 | * i.e. RFC 1885 2.4(e) |
| 393 | * Rule (e.1) is enforced by not using icmpv6_send |
| 394 | * in any code that processes icmp errors. |
| 395 | */ |
| 396 | addr_type = ipv6_addr_type(&hdr->daddr); |
| 397 | |
| 398 | if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0)) |
| 399 | saddr = &hdr->daddr; |
| 400 | |
| 401 | /* |
| 402 | * Dest addr check |
| 403 | */ |
| 404 | |
| 405 | if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { |
| 406 | if (type != ICMPV6_PKT_TOOBIG && |
| 407 | !(type == ICMPV6_PARAMPROB && |
| 408 | code == ICMPV6_UNK_OPTION && |
| 409 | (opt_unrec(skb, info)))) |
| 410 | return; |
| 411 | |
| 412 | saddr = NULL; |
| 413 | } |
| 414 | |
| 415 | addr_type = ipv6_addr_type(&hdr->saddr); |
| 416 | |
| 417 | /* |
| 418 | * Source addr check |
| 419 | */ |
| 420 | |
| 421 | if (addr_type & IPV6_ADDR_LINKLOCAL) |
| 422 | iif = skb->dev->ifindex; |
| 423 | |
| 424 | /* |
| 425 | * Must not send error if the source does not uniquely |
| 426 | * identify a single node (RFC2463 Section 2.4). |
| 427 | * We check unspecified / multicast addresses here, |
| 428 | * and anycast addresses will be checked later. |
| 429 | */ |
| 430 | if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { |
| 431 | LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n"); |
| 432 | return; |
| 433 | } |
| 434 | |
| 435 | /* |
| 436 | * Never answer to a ICMP packet. |
| 437 | */ |
| 438 | if (is_ineligible(skb)) { |
| 439 | LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n"); |
| 440 | return; |
| 441 | } |
| 442 | |
| 443 | mip6_addr_swap(skb); |
| 444 | |
| 445 | memset(&fl6, 0, sizeof(fl6)); |
| 446 | fl6.flowi6_proto = IPPROTO_ICMPV6; |
| 447 | fl6.daddr = hdr->saddr; |
| 448 | if (saddr) |
| 449 | fl6.saddr = *saddr; |
| 450 | fl6.flowi6_oif = iif; |
| 451 | fl6.fl6_icmp_type = type; |
| 452 | fl6.fl6_icmp_code = code; |
| 453 | security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); |
| 454 | |
| 455 | sk = icmpv6_xmit_lock(net); |
| 456 | if (sk == NULL) |
| 457 | return; |
| 458 | np = inet6_sk(sk); |
| 459 | |
| 460 | if (!icmpv6_xrlim_allow(sk, type, &fl6)) |
| 461 | goto out; |
| 462 | |
| 463 | tmp_hdr.icmp6_type = type; |
| 464 | tmp_hdr.icmp6_code = code; |
| 465 | tmp_hdr.icmp6_cksum = 0; |
| 466 | tmp_hdr.icmp6_pointer = htonl(info); |
| 467 | |
| 468 | if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) |
| 469 | fl6.flowi6_oif = np->mcast_oif; |
| 470 | |
| 471 | dst = icmpv6_route_lookup(net, skb, sk, &fl6); |
| 472 | if (IS_ERR(dst)) |
| 473 | goto out; |
| 474 | |
| 475 | if (ipv6_addr_is_multicast(&fl6.daddr)) |
| 476 | hlimit = np->mcast_hops; |
| 477 | else |
| 478 | hlimit = np->hop_limit; |
| 479 | if (hlimit < 0) |
| 480 | hlimit = ip6_dst_hoplimit(dst); |
| 481 | |
| 482 | msg.skb = skb; |
| 483 | msg.offset = skb_network_offset(skb); |
| 484 | msg.type = type; |
| 485 | |
| 486 | len = skb->len - msg.offset; |
| 487 | len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr)); |
| 488 | if (len < 0) { |
| 489 | LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); |
| 490 | goto out_dst_release; |
| 491 | } |
| 492 | |
| 493 | rcu_read_lock(); |
| 494 | idev = __in6_dev_get(skb->dev); |
| 495 | |
| 496 | err = ip6_append_data(sk, icmpv6_getfrag, &msg, |
| 497 | len + sizeof(struct icmp6hdr), |
| 498 | sizeof(struct icmp6hdr), hlimit, |
| 499 | np->tclass, NULL, &fl6, (struct rt6_info*)dst, |
| 500 | MSG_DONTWAIT, np->dontfrag); |
| 501 | if (err) { |
| 502 | ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); |
| 503 | ip6_flush_pending_frames(sk); |
| 504 | } else { |
| 505 | err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, |
| 506 | len + sizeof(struct icmp6hdr)); |
| 507 | } |
| 508 | rcu_read_unlock(); |
| 509 | out_dst_release: |
| 510 | dst_release(dst); |
| 511 | out: |
| 512 | icmpv6_xmit_unlock(sk); |
| 513 | } |
| 514 | EXPORT_SYMBOL(icmpv6_send); |
| 515 | |
| 516 | static void icmpv6_echo_reply(struct sk_buff *skb) |
| 517 | { |
| 518 | struct net *net = dev_net(skb->dev); |
| 519 | struct sock *sk; |
| 520 | struct inet6_dev *idev; |
| 521 | struct ipv6_pinfo *np; |
| 522 | const struct in6_addr *saddr = NULL; |
| 523 | struct icmp6hdr *icmph = icmp6_hdr(skb); |
| 524 | struct icmp6hdr tmp_hdr; |
| 525 | struct flowi6 fl6; |
| 526 | struct icmpv6_msg msg; |
| 527 | struct dst_entry *dst; |
| 528 | int err = 0; |
| 529 | int hlimit; |
| 530 | |
| 531 | saddr = &ipv6_hdr(skb)->daddr; |
| 532 | |
| 533 | if (!ipv6_unicast_destination(skb)) |
| 534 | saddr = NULL; |
| 535 | |
| 536 | memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); |
| 537 | tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; |
| 538 | |
| 539 | memset(&fl6, 0, sizeof(fl6)); |
| 540 | fl6.flowi6_proto = IPPROTO_ICMPV6; |
| 541 | fl6.daddr = ipv6_hdr(skb)->saddr; |
| 542 | if (saddr) |
| 543 | fl6.saddr = *saddr; |
| 544 | fl6.flowi6_oif = skb->dev->ifindex; |
| 545 | fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; |
| 546 | security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); |
| 547 | |
| 548 | sk = icmpv6_xmit_lock(net); |
| 549 | if (sk == NULL) |
| 550 | return; |
| 551 | np = inet6_sk(sk); |
| 552 | |
| 553 | if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) |
| 554 | fl6.flowi6_oif = np->mcast_oif; |
| 555 | |
| 556 | err = ip6_dst_lookup(sk, &dst, &fl6); |
| 557 | if (err) |
| 558 | goto out; |
| 559 | dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); |
| 560 | if (IS_ERR(dst)) |
| 561 | goto out; |
| 562 | |
| 563 | if (ipv6_addr_is_multicast(&fl6.daddr)) |
| 564 | hlimit = np->mcast_hops; |
| 565 | else |
| 566 | hlimit = np->hop_limit; |
| 567 | if (hlimit < 0) |
| 568 | hlimit = ip6_dst_hoplimit(dst); |
| 569 | |
| 570 | idev = __in6_dev_get(skb->dev); |
| 571 | |
| 572 | msg.skb = skb; |
| 573 | msg.offset = 0; |
| 574 | msg.type = ICMPV6_ECHO_REPLY; |
| 575 | |
| 576 | err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), |
| 577 | sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6, |
| 578 | (struct rt6_info*)dst, MSG_DONTWAIT, |
| 579 | np->dontfrag); |
| 580 | |
| 581 | if (err) { |
| 582 | ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); |
| 583 | ip6_flush_pending_frames(sk); |
| 584 | } else { |
| 585 | err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, |
| 586 | skb->len + sizeof(struct icmp6hdr)); |
| 587 | } |
| 588 | dst_release(dst); |
| 589 | out: |
| 590 | icmpv6_xmit_unlock(sk); |
| 591 | } |
| 592 | |
| 593 | static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) |
| 594 | { |
| 595 | const struct inet6_protocol *ipprot; |
| 596 | int inner_offset; |
| 597 | int hash; |
| 598 | u8 nexthdr; |
| 599 | |
| 600 | if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) |
| 601 | return; |
| 602 | |
| 603 | nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; |
| 604 | if (ipv6_ext_hdr(nexthdr)) { |
| 605 | /* now skip over extension headers */ |
| 606 | inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr); |
| 607 | if (inner_offset<0) |
| 608 | return; |
| 609 | } else { |
| 610 | inner_offset = sizeof(struct ipv6hdr); |
| 611 | } |
| 612 | |
| 613 | /* Checkin header including 8 bytes of inner protocol header. */ |
| 614 | if (!pskb_may_pull(skb, inner_offset+8)) |
| 615 | return; |
| 616 | |
| 617 | /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. |
| 618 | Without this we will not able f.e. to make source routed |
| 619 | pmtu discovery. |
| 620 | Corresponding argument (opt) to notifiers is already added. |
| 621 | --ANK (980726) |
| 622 | */ |
| 623 | |
| 624 | hash = nexthdr & (MAX_INET_PROTOS - 1); |
| 625 | |
| 626 | rcu_read_lock(); |
| 627 | ipprot = rcu_dereference(inet6_protos[hash]); |
| 628 | if (ipprot && ipprot->err_handler) |
| 629 | ipprot->err_handler(skb, NULL, type, code, inner_offset, info); |
| 630 | rcu_read_unlock(); |
| 631 | |
| 632 | raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); |
| 633 | } |
| 634 | |
| 635 | /* |
| 636 | * Handle icmp messages |
| 637 | */ |
| 638 | |
| 639 | static int icmpv6_rcv(struct sk_buff *skb) |
| 640 | { |
| 641 | struct net_device *dev = skb->dev; |
| 642 | struct inet6_dev *idev = __in6_dev_get(dev); |
| 643 | const struct in6_addr *saddr, *daddr; |
| 644 | const struct ipv6hdr *orig_hdr; |
| 645 | struct icmp6hdr *hdr; |
| 646 | u8 type; |
| 647 | |
| 648 | if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { |
| 649 | struct sec_path *sp = skb_sec_path(skb); |
| 650 | int nh; |
| 651 | |
| 652 | if (!(sp && sp->xvec[sp->len - 1]->props.flags & |
| 653 | XFRM_STATE_ICMP)) |
| 654 | goto drop_no_count; |
| 655 | |
| 656 | if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr))) |
| 657 | goto drop_no_count; |
| 658 | |
| 659 | nh = skb_network_offset(skb); |
| 660 | skb_set_network_header(skb, sizeof(*hdr)); |
| 661 | |
| 662 | if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) |
| 663 | goto drop_no_count; |
| 664 | |
| 665 | skb_set_network_header(skb, nh); |
| 666 | } |
| 667 | |
| 668 | ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); |
| 669 | |
| 670 | saddr = &ipv6_hdr(skb)->saddr; |
| 671 | daddr = &ipv6_hdr(skb)->daddr; |
| 672 | |
| 673 | /* Perform checksum. */ |
| 674 | switch (skb->ip_summed) { |
| 675 | case CHECKSUM_COMPLETE: |
| 676 | if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6, |
| 677 | skb->csum)) |
| 678 | break; |
| 679 | /* fall through */ |
| 680 | case CHECKSUM_NONE: |
| 681 | skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len, |
| 682 | IPPROTO_ICMPV6, 0)); |
| 683 | if (__skb_checksum_complete(skb)) { |
| 684 | LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n", |
| 685 | saddr, daddr); |
| 686 | goto discard_it; |
| 687 | } |
| 688 | } |
| 689 | |
| 690 | if (!pskb_pull(skb, sizeof(*hdr))) |
| 691 | goto discard_it; |
| 692 | |
| 693 | hdr = icmp6_hdr(skb); |
| 694 | |
| 695 | type = hdr->icmp6_type; |
| 696 | |
| 697 | ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); |
| 698 | |
| 699 | switch (type) { |
| 700 | case ICMPV6_ECHO_REQUEST: |
| 701 | icmpv6_echo_reply(skb); |
| 702 | break; |
| 703 | |
| 704 | case ICMPV6_ECHO_REPLY: |
| 705 | /* we couldn't care less */ |
| 706 | break; |
| 707 | |
| 708 | case ICMPV6_PKT_TOOBIG: |
| 709 | /* BUGGG_FUTURE: if packet contains rthdr, we cannot update |
| 710 | standard destination cache. Seems, only "advanced" |
| 711 | destination cache will allow to solve this problem |
| 712 | --ANK (980726) |
| 713 | */ |
| 714 | if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) |
| 715 | goto discard_it; |
| 716 | hdr = icmp6_hdr(skb); |
| 717 | orig_hdr = (struct ipv6hdr *) (hdr + 1); |
| 718 | rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev, |
| 719 | ntohl(hdr->icmp6_mtu)); |
| 720 | |
| 721 | /* |
| 722 | * Drop through to notify |
| 723 | */ |
| 724 | |
| 725 | case ICMPV6_DEST_UNREACH: |
| 726 | case ICMPV6_TIME_EXCEED: |
| 727 | case ICMPV6_PARAMPROB: |
| 728 | icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); |
| 729 | break; |
| 730 | |
| 731 | case NDISC_ROUTER_SOLICITATION: |
| 732 | case NDISC_ROUTER_ADVERTISEMENT: |
| 733 | case NDISC_NEIGHBOUR_SOLICITATION: |
| 734 | case NDISC_NEIGHBOUR_ADVERTISEMENT: |
| 735 | case NDISC_REDIRECT: |
| 736 | ndisc_rcv(skb); |
| 737 | break; |
| 738 | |
| 739 | case ICMPV6_MGM_QUERY: |
| 740 | igmp6_event_query(skb); |
| 741 | break; |
| 742 | |
| 743 | case ICMPV6_MGM_REPORT: |
| 744 | igmp6_event_report(skb); |
| 745 | break; |
| 746 | |
| 747 | case ICMPV6_MGM_REDUCTION: |
| 748 | case ICMPV6_NI_QUERY: |
| 749 | case ICMPV6_NI_REPLY: |
| 750 | case ICMPV6_MLD2_REPORT: |
| 751 | case ICMPV6_DHAAD_REQUEST: |
| 752 | case ICMPV6_DHAAD_REPLY: |
| 753 | case ICMPV6_MOBILE_PREFIX_SOL: |
| 754 | case ICMPV6_MOBILE_PREFIX_ADV: |
| 755 | break; |
| 756 | |
| 757 | default: |
| 758 | LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n"); |
| 759 | |
| 760 | /* informational */ |
| 761 | if (type & ICMPV6_INFOMSG_MASK) |
| 762 | break; |
| 763 | |
| 764 | /* |
| 765 | * error of unknown type. |
| 766 | * must pass to upper level |
| 767 | */ |
| 768 | |
| 769 | icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); |
| 770 | } |
| 771 | |
| 772 | kfree_skb(skb); |
| 773 | return 0; |
| 774 | |
| 775 | discard_it: |
| 776 | ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); |
| 777 | drop_no_count: |
| 778 | kfree_skb(skb); |
| 779 | return 0; |
| 780 | } |
| 781 | |
| 782 | void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, |
| 783 | u8 type, |
| 784 | const struct in6_addr *saddr, |
| 785 | const struct in6_addr *daddr, |
| 786 | int oif) |
| 787 | { |
| 788 | memset(fl6, 0, sizeof(*fl6)); |
| 789 | fl6->saddr = *saddr; |
| 790 | fl6->daddr = *daddr; |
| 791 | fl6->flowi6_proto = IPPROTO_ICMPV6; |
| 792 | fl6->fl6_icmp_type = type; |
| 793 | fl6->fl6_icmp_code = 0; |
| 794 | fl6->flowi6_oif = oif; |
| 795 | security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); |
| 796 | } |
| 797 | |
| 798 | /* |
| 799 | * Special lock-class for __icmpv6_sk: |
| 800 | */ |
| 801 | static struct lock_class_key icmpv6_socket_sk_dst_lock_key; |
| 802 | |
| 803 | static int __net_init icmpv6_sk_init(struct net *net) |
| 804 | { |
| 805 | struct sock *sk; |
| 806 | int err, i, j; |
| 807 | |
| 808 | net->ipv6.icmp_sk = |
| 809 | kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); |
| 810 | if (net->ipv6.icmp_sk == NULL) |
| 811 | return -ENOMEM; |
| 812 | |
| 813 | for_each_possible_cpu(i) { |
| 814 | err = inet_ctl_sock_create(&sk, PF_INET6, |
| 815 | SOCK_RAW, IPPROTO_ICMPV6, net); |
| 816 | if (err < 0) { |
| 817 | printk(KERN_ERR |
| 818 | "Failed to initialize the ICMP6 control socket " |
| 819 | "(err %d).\n", |
| 820 | err); |
| 821 | goto fail; |
| 822 | } |
| 823 | |
| 824 | net->ipv6.icmp_sk[i] = sk; |
| 825 | |
| 826 | /* |
| 827 | * Split off their lock-class, because sk->sk_dst_lock |
| 828 | * gets used from softirqs, which is safe for |
| 829 | * __icmpv6_sk (because those never get directly used |
| 830 | * via userspace syscalls), but unsafe for normal sockets. |
| 831 | */ |
| 832 | lockdep_set_class(&sk->sk_dst_lock, |
| 833 | &icmpv6_socket_sk_dst_lock_key); |
| 834 | |
| 835 | /* Enough space for 2 64K ICMP packets, including |
| 836 | * sk_buff struct overhead. |
| 837 | */ |
| 838 | sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); |
| 839 | } |
| 840 | return 0; |
| 841 | |
| 842 | fail: |
| 843 | for (j = 0; j < i; j++) |
| 844 | inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); |
| 845 | kfree(net->ipv6.icmp_sk); |
| 846 | return err; |
| 847 | } |
| 848 | |
| 849 | static void __net_exit icmpv6_sk_exit(struct net *net) |
| 850 | { |
| 851 | int i; |
| 852 | |
| 853 | for_each_possible_cpu(i) { |
| 854 | inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); |
| 855 | } |
| 856 | kfree(net->ipv6.icmp_sk); |
| 857 | } |
| 858 | |
| 859 | static struct pernet_operations icmpv6_sk_ops = { |
| 860 | .init = icmpv6_sk_init, |
| 861 | .exit = icmpv6_sk_exit, |
| 862 | }; |
| 863 | |
| 864 | int __init icmpv6_init(void) |
| 865 | { |
| 866 | int err; |
| 867 | |
| 868 | err = register_pernet_subsys(&icmpv6_sk_ops); |
| 869 | if (err < 0) |
| 870 | return err; |
| 871 | |
| 872 | err = -EAGAIN; |
| 873 | if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) |
| 874 | goto fail; |
| 875 | return 0; |
| 876 | |
| 877 | fail: |
| 878 | printk(KERN_ERR "Failed to register ICMP6 protocol\n"); |
| 879 | unregister_pernet_subsys(&icmpv6_sk_ops); |
| 880 | return err; |
| 881 | } |
| 882 | |
| 883 | void icmpv6_cleanup(void) |
| 884 | { |
| 885 | unregister_pernet_subsys(&icmpv6_sk_ops); |
| 886 | inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); |
| 887 | } |
| 888 | |
| 889 | |
| 890 | static const struct icmp6_err { |
| 891 | int err; |
| 892 | int fatal; |
| 893 | } tab_unreach[] = { |
| 894 | { /* NOROUTE */ |
| 895 | .err = ENETUNREACH, |
| 896 | .fatal = 0, |
| 897 | }, |
| 898 | { /* ADM_PROHIBITED */ |
| 899 | .err = EACCES, |
| 900 | .fatal = 1, |
| 901 | }, |
| 902 | { /* Was NOT_NEIGHBOUR, now reserved */ |
| 903 | .err = EHOSTUNREACH, |
| 904 | .fatal = 0, |
| 905 | }, |
| 906 | { /* ADDR_UNREACH */ |
| 907 | .err = EHOSTUNREACH, |
| 908 | .fatal = 0, |
| 909 | }, |
| 910 | { /* PORT_UNREACH */ |
| 911 | .err = ECONNREFUSED, |
| 912 | .fatal = 1, |
| 913 | }, |
| 914 | }; |
| 915 | |
| 916 | int icmpv6_err_convert(u8 type, u8 code, int *err) |
| 917 | { |
| 918 | int fatal = 0; |
| 919 | |
| 920 | *err = EPROTO; |
| 921 | |
| 922 | switch (type) { |
| 923 | case ICMPV6_DEST_UNREACH: |
| 924 | fatal = 1; |
| 925 | if (code <= ICMPV6_PORT_UNREACH) { |
| 926 | *err = tab_unreach[code].err; |
| 927 | fatal = tab_unreach[code].fatal; |
| 928 | } |
| 929 | break; |
| 930 | |
| 931 | case ICMPV6_PKT_TOOBIG: |
| 932 | *err = EMSGSIZE; |
| 933 | break; |
| 934 | |
| 935 | case ICMPV6_PARAMPROB: |
| 936 | *err = EPROTO; |
| 937 | fatal = 1; |
| 938 | break; |
| 939 | |
| 940 | case ICMPV6_TIME_EXCEED: |
| 941 | *err = EHOSTUNREACH; |
| 942 | break; |
| 943 | } |
| 944 | |
| 945 | return fatal; |
| 946 | } |
| 947 | |
| 948 | EXPORT_SYMBOL(icmpv6_err_convert); |
| 949 | |
| 950 | #ifdef CONFIG_SYSCTL |
| 951 | ctl_table ipv6_icmp_table_template[] = { |
| 952 | { |
| 953 | .procname = "ratelimit", |
| 954 | .data = &init_net.ipv6.sysctl.icmpv6_time, |
| 955 | .maxlen = sizeof(int), |
| 956 | .mode = 0644, |
| 957 | .proc_handler = proc_dointvec_ms_jiffies, |
| 958 | }, |
| 959 | { }, |
| 960 | }; |
| 961 | |
| 962 | struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) |
| 963 | { |
| 964 | struct ctl_table *table; |
| 965 | |
| 966 | table = kmemdup(ipv6_icmp_table_template, |
| 967 | sizeof(ipv6_icmp_table_template), |
| 968 | GFP_KERNEL); |
| 969 | |
| 970 | if (table) |
| 971 | table[0].data = &net->ipv6.sysctl.icmpv6_time; |
| 972 | |
| 973 | return table; |
| 974 | } |
| 975 | #endif |
| 976 | |