net/ipv6/datagram.c

   1 /*
   2  *      common UDP/RAW code
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <[email protected]>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/capability.h>
  15 #include <linux/errno.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/socket.h>
  20 #include <linux/sockios.h>
  21 #include <linux/in6.h>
  22 #include <linux/ipv6.h>
  23 #include <linux/route.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26
  27 #include <net/ipv6.h>
  28 #include <net/ndisc.h>
  29 #include <net/addrconf.h>
  30 #include <net/transp_v6.h>
  31 #include <net/ip6_route.h>
  32 #include <net/tcp_states.h>
  33 #include <net/dsfield.h>
  34
  35 #include <linux/errqueue.h>
  36 #include <asm/uaccess.h>
  37
  38 static bool ipv6_mapped_addr_any(const struct in6_addr *a)
  39 {
  40         return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
  41 }
  42
  43 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
  44 {
  45         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
  46         struct inet_sock        *inet = inet_sk(sk);
  47         struct ipv6_pinfo       *np = inet6_sk(sk);
  48         struct in6_addr         *daddr, *final_p, final;
  49         struct dst_entry        *dst;
  50         struct flowi6           fl6;
  51         struct ip6_flowlabel    *flowlabel = NULL;
  52         struct ipv6_txoptions   *opt;
  53         int                     addr_type;
  54         int                     err;
  55
  56         if (usin->sin6_family == AF_INET) {
  57                 if (__ipv6_only_sock(sk))
  58                         return -EAFNOSUPPORT;
  59                 err = ip4_datagram_connect(sk, uaddr, addr_len);
  60                 goto ipv4_connected;
  61         }
  62
  63         if (addr_len < SIN6_LEN_RFC2133)
  64                 return -EINVAL;
  65
  66         if (usin->sin6_family != AF_INET6)
  67                 return -EAFNOSUPPORT;
  68
  69         memset(&fl6, 0, sizeof(fl6));
  70         if (np->sndflow) {
  71                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
  72                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
  73                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
  74                         if (flowlabel == NULL)
  75                                 return -EINVAL;
  76                         usin->sin6_addr = flowlabel->dst;
  77                 }
  78         }
  79
  80         addr_type = ipv6_addr_type(&usin->sin6_addr);
  81
  82         if (addr_type == IPV6_ADDR_ANY) {
  83                 /*
  84                  *      connect to self
  85                  */
  86                 usin->sin6_addr.s6_addr[15] = 0x01;
  87         }
  88
  89         daddr = &usin->sin6_addr;
  90
  91         if (addr_type == IPV6_ADDR_MAPPED) {
  92                 struct sockaddr_in sin;
  93
  94                 if (__ipv6_only_sock(sk)) {
  95                         err = -ENETUNREACH;
  96                         goto out;
  97                 }
  98                 sin.sin_family = AF_INET;
  99                 sin.sin_addr.s_addr = daddr->s6_addr32[3];
 100                 sin.sin_port = usin->sin6_port;
 101
 102                 err = ip4_datagram_connect(sk,
 103                                            (struct sockaddr *) &sin,
 104                                            sizeof(sin));
 105
 106 ipv4_connected:
 107                 if (err)
 108                         goto out;
 109
 110                 ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
 111
 112                 if (ipv6_addr_any(&np->saddr) ||
 113                     ipv6_mapped_addr_any(&np->saddr))
 114                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 115
 116                 if (ipv6_addr_any(&np->rcv_saddr) ||
 117                     ipv6_mapped_addr_any(&np->rcv_saddr)) {
 118                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 119                                                &np->rcv_saddr);
 120                         if (sk->sk_prot->rehash)
 121                                 sk->sk_prot->rehash(sk);
 122                 }
 123
 124                 goto out;
 125         }
 126
 127         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 128                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 129                     usin->sin6_scope_id) {
 130                         if (sk->sk_bound_dev_if &&
 131                             sk->sk_bound_dev_if != usin->sin6_scope_id) {
 132                                 err = -EINVAL;
 133                                 goto out;
 134                         }
 135                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 136                 }
 137
 138                 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
 139                         sk->sk_bound_dev_if = np->mcast_oif;
 140
 141                 /* Connect to link-local address requires an interface */
 142                 if (!sk->sk_bound_dev_if) {
 143                         err = -EINVAL;
 144                         goto out;
 145                 }
 146         }
 147
 148         np->daddr = *daddr;
 149         np->flow_label = fl6.flowlabel;
 150
 151         inet->inet_dport = usin->sin6_port;
 152
 153         /*
 154          *      Check for a route to destination an obtain the
 155          *      destination cache for it.
 156          */
 157
 158         fl6.flowi6_proto = sk->sk_protocol;
 159         fl6.daddr = np->daddr;
 160         fl6.saddr = np->saddr;
 161         fl6.flowi6_oif = sk->sk_bound_dev_if;
 162         fl6.flowi6_mark = sk->sk_mark;
 163         fl6.fl6_dport = inet->inet_dport;
 164         fl6.fl6_sport = inet->inet_sport;
 165
 166         if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 167                 fl6.flowi6_oif = np->mcast_oif;
 168
 169         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 170
 171         opt = flowlabel ? flowlabel->opt : np->opt;
 172         final_p = fl6_update_dst(&fl6, opt, &final);
 173
 174         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 175         err = 0;
 176         if (IS_ERR(dst)) {
 177                 err = PTR_ERR(dst);
 178                 goto out;
 179         }
 180
 181         /* source address lookup done in ip6_dst_lookup */
 182
 183         if (ipv6_addr_any(&np->saddr))
 184                 np->saddr = fl6.saddr;
 185
 186         if (ipv6_addr_any(&np->rcv_saddr)) {
 187                 np->rcv_saddr = fl6.saddr;
 188                 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 189                 if (sk->sk_prot->rehash)
 190                         sk->sk_prot->rehash(sk);
 191         }
 192
 193         ip6_dst_store(sk, dst,
 194                       ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
 195                       &np->daddr : NULL,
 196 #ifdef CONFIG_IPV6_SUBTREES
 197                       ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
 198                       &np->saddr :
 199 #endif
 200                       NULL);
 201
 202         sk->sk_state = TCP_ESTABLISHED;
 203 out:
 204         fl6_sock_release(flowlabel);
 205         return err;
 206 }
 207 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
 208
 209 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 210                      __be16 port, u32 info, u8 *payload)
 211 {
 212         struct ipv6_pinfo *np  = inet6_sk(sk);
 213         struct icmp6hdr *icmph = icmp6_hdr(skb);
 214         struct sock_exterr_skb *serr;
 215
 216         if (!np->recverr)
 217                 return;
 218
 219         skb = skb_clone(skb, GFP_ATOMIC);
 220         if (!skb)
 221                 return;
 222
 223         skb->protocol = htons(ETH_P_IPV6);
 224
 225         serr = SKB_EXT_ERR(skb);
 226         serr->ee.ee_errno = err;
 227         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 228         serr->ee.ee_type = icmph->icmp6_type;
 229         serr->ee.ee_code = icmph->icmp6_code;
 230         serr->ee.ee_pad = 0;
 231         serr->ee.ee_info = info;
 232         serr->ee.ee_data = 0;
 233         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
 234                                   skb_network_header(skb);
 235         serr->port = port;
 236
 237         __skb_pull(skb, payload - skb->data);
 238         skb_reset_transport_header(skb);
 239
 240         if (sock_queue_err_skb(sk, skb))
 241                 kfree_skb(skb);
 242 }
 243
 244 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 245 {
 246         struct ipv6_pinfo *np = inet6_sk(sk);
 247         struct sock_exterr_skb *serr;
 248         struct ipv6hdr *iph;
 249         struct sk_buff *skb;
 250
 251         if (!np->recverr)
 252                 return;
 253
 254         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 255         if (!skb)
 256                 return;
 257
 258         skb->protocol = htons(ETH_P_IPV6);
 259
 260         skb_put(skb, sizeof(struct ipv6hdr));
 261         skb_reset_network_header(skb);
 262         iph = ipv6_hdr(skb);
 263         iph->daddr = fl6->daddr;
 264
 265         serr = SKB_EXT_ERR(skb);
 266         serr->ee.ee_errno = err;
 267         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
 268         serr->ee.ee_type = 0;
 269         serr->ee.ee_code = 0;
 270         serr->ee.ee_pad = 0;
 271         serr->ee.ee_info = info;
 272         serr->ee.ee_data = 0;
 273         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 274         serr->port = fl6->fl6_dport;
 275
 276         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 277         skb_reset_transport_header(skb);
 278
 279         if (sock_queue_err_skb(sk, skb))
 280                 kfree_skb(skb);
 281 }
 282
 283 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 284 {
 285         struct ipv6_pinfo *np = inet6_sk(sk);
 286         struct ipv6hdr *iph;
 287         struct sk_buff *skb;
 288         struct ip6_mtuinfo *mtu_info;
 289
 290         if (!np->rxopt.bits.rxpmtu)
 291                 return;
 292
 293         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 294         if (!skb)
 295                 return;
 296
 297         skb_put(skb, sizeof(struct ipv6hdr));
 298         skb_reset_network_header(skb);
 299         iph = ipv6_hdr(skb);
 300         iph->daddr = fl6->daddr;
 301
 302         mtu_info = IP6CBMTU(skb);
 303
 304         mtu_info->ip6m_mtu = mtu;
 305         mtu_info->ip6m_addr.sin6_family = AF_INET6;
 306         mtu_info->ip6m_addr.sin6_port = 0;
 307         mtu_info->ip6m_addr.sin6_flowinfo = 0;
 308         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
 309         mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
 310
 311         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 312         skb_reset_transport_header(skb);
 313
 314         skb = xchg(&np->rxpmtu, skb);
 315         kfree_skb(skb);
 316 }
 317
 318 /*
 319  *      Handle MSG_ERRQUEUE
 320  */
 321 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
 322 {
 323         struct ipv6_pinfo *np = inet6_sk(sk);
 324         struct sock_exterr_skb *serr;
 325         struct sk_buff *skb, *skb2;
 326         struct sockaddr_in6 *sin;
 327         struct {
 328                 struct sock_extended_err ee;
 329                 struct sockaddr_in6      offender;
 330         } errhdr;
 331         int err;
 332         int copied;
 333
 334         err = -EAGAIN;
 335         skb = skb_dequeue(&sk->sk_error_queue);
 336         if (skb == NULL)
 337                 goto out;
 338
 339         copied = skb->len;
 340         if (copied > len) {
 341                 msg->msg_flags |= MSG_TRUNC;
 342                 copied = len;
 343         }
 344         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 345         if (err)
 346                 goto out_free_skb;
 347
 348         sock_recv_timestamp(msg, sk, skb);
 349
 350         serr = SKB_EXT_ERR(skb);
 351
 352         sin = (struct sockaddr_in6 *)msg->msg_name;
 353         if (sin) {
 354                 const unsigned char *nh = skb_network_header(skb);
 355                 sin->sin6_family = AF_INET6;
 356                 sin->sin6_flowinfo = 0;
 357                 sin->sin6_port = serr->port;
 358                 sin->sin6_scope_id = 0;
 359                 if (skb->protocol == htons(ETH_P_IPV6)) {
 360                         const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
 361                                                                   struct ipv6hdr, daddr);
 362                         sin->sin6_addr = ip6h->daddr;
 363                         if (np->sndflow)
 364                                 sin->sin6_flowinfo = ip6_flowinfo(ip6h);
 365                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 366                                 sin->sin6_scope_id = IP6CB(skb)->iif;
 367                 } else {
 368                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
 369                                                &sin->sin6_addr);
 370                 }
 371         }
 372
 373         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 374         sin = &errhdr.offender;
 375         sin->sin6_family = AF_UNSPEC;
 376         if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
 377                 sin->sin6_family = AF_INET6;
 378                 sin->sin6_flowinfo = 0;
 379                 sin->sin6_scope_id = 0;
 380                 if (skb->protocol == htons(ETH_P_IPV6)) {
 381                         sin->sin6_addr = ipv6_hdr(skb)->saddr;
 382                         if (np->rxopt.all)
 383                                 ip6_datagram_recv_ctl(sk, msg, skb);
 384                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 385                                 sin->sin6_scope_id = IP6CB(skb)->iif;
 386                 } else {
 387                         struct inet_sock *inet = inet_sk(sk);
 388
 389                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
 390                                                &sin->sin6_addr);
 391                         if (inet->cmsg_flags)
 392                                 ip_cmsg_recv(msg, skb);
 393                 }
 394         }
 395
 396         put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
 397
 398         /* Now we could try to dump offended packet options */
 399
 400         msg->msg_flags |= MSG_ERRQUEUE;
 401         err = copied;
 402
 403         /* Reset and regenerate socket error */
 404         spin_lock_bh(&sk->sk_error_queue.lock);
 405         sk->sk_err = 0;
 406         if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
 407                 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
 408                 spin_unlock_bh(&sk->sk_error_queue.lock);
 409                 sk->sk_error_report(sk);
 410         } else {
 411                 spin_unlock_bh(&sk->sk_error_queue.lock);
 412         }
 413
 414 out_free_skb:
 415         kfree_skb(skb);
 416 out:
 417         return err;
 418 }
 419 EXPORT_SYMBOL_GPL(ipv6_recv_error);
 420
 421 /*
 422  *      Handle IPV6_RECVPATHMTU
 423  */
 424 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
 425 {
 426         struct ipv6_pinfo *np = inet6_sk(sk);
 427         struct sk_buff *skb;
 428         struct sockaddr_in6 *sin;
 429         struct ip6_mtuinfo mtu_info;
 430         int err;
 431         int copied;
 432
 433         err = -EAGAIN;
 434         skb = xchg(&np->rxpmtu, NULL);
 435         if (skb == NULL)
 436                 goto out;
 437
 438         copied = skb->len;
 439         if (copied > len) {
 440                 msg->msg_flags |= MSG_TRUNC;
 441                 copied = len;
 442         }
 443         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 444         if (err)
 445                 goto out_free_skb;
 446
 447         sock_recv_timestamp(msg, sk, skb);
 448
 449         memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
 450
 451         sin = (struct sockaddr_in6 *)msg->msg_name;
 452         if (sin) {
 453                 sin->sin6_family = AF_INET6;
 454                 sin->sin6_flowinfo = 0;
 455                 sin->sin6_port = 0;
 456                 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
 457                 sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
 458         }
 459
 460         put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
 461
 462         err = copied;
 463
 464 out_free_skb:
 465         kfree_skb(skb);
 466 out:
 467         return err;
 468 }
 469
 470
 471 int ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
 472                           struct sk_buff *skb)
 473 {
 474         struct ipv6_pinfo *np = inet6_sk(sk);
 475         struct inet6_skb_parm *opt = IP6CB(skb);
 476         unsigned char *nh = skb_network_header(skb);
 477
 478         if (np->rxopt.bits.rxinfo) {
 479                 struct in6_pktinfo src_info;
 480
 481                 src_info.ipi6_ifindex = opt->iif;
 482                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 483                 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
 484         }
 485
 486         if (np->rxopt.bits.rxhlim) {
 487                 int hlim = ipv6_hdr(skb)->hop_limit;
 488                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
 489         }
 490
 491         if (np->rxopt.bits.rxtclass) {
 492                 int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 493                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 494         }
 495
 496         if (np->rxopt.bits.rxflow) {
 497                 __be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
 498                 if (flowinfo)
 499                         put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
 500         }
 501
 502         /* HbH is allowed only once */
 503         if (np->rxopt.bits.hopopts && opt->hop) {
 504                 u8 *ptr = nh + opt->hop;
 505                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
 506         }
 507
 508         if (opt->lastopt &&
 509             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
 510                 /*
 511                  * Silly enough, but we need to reparse in order to
 512                  * report extension headers (except for HbH)
 513                  * in order.
 514                  *
 515                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
 516                  * (and WILL NOT be) defined because
 517                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
 518                  */
 519                 unsigned int off = sizeof(struct ipv6hdr);
 520                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 521
 522                 while (off <= opt->lastopt) {
 523                         unsigned int len;
 524                         u8 *ptr = nh + off;
 525
 526                         switch (nexthdr) {
 527                         case IPPROTO_DSTOPTS:
 528                                 nexthdr = ptr[0];
 529                                 len = (ptr[1] + 1) << 3;
 530                                 if (np->rxopt.bits.dstopts)
 531                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
 532                                 break;
 533                         case IPPROTO_ROUTING:
 534                                 nexthdr = ptr[0];
 535                                 len = (ptr[1] + 1) << 3;
 536                                 if (np->rxopt.bits.srcrt)
 537                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
 538                                 break;
 539                         case IPPROTO_AH:
 540                                 nexthdr = ptr[0];
 541                                 len = (ptr[1] + 2) << 2;
 542                                 break;
 543                         default:
 544                                 nexthdr = ptr[0];
 545                                 len = (ptr[1] + 1) << 3;
 546                                 break;
 547                         }
 548
 549                         off += len;
 550                 }
 551         }
 552
 553         /* socket options in old style */
 554         if (np->rxopt.bits.rxoinfo) {
 555                 struct in6_pktinfo src_info;
 556
 557                 src_info.ipi6_ifindex = opt->iif;
 558                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 559                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
 560         }
 561         if (np->rxopt.bits.rxohlim) {
 562                 int hlim = ipv6_hdr(skb)->hop_limit;
 563                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
 564         }
 565         if (np->rxopt.bits.ohopopts && opt->hop) {
 566                 u8 *ptr = nh + opt->hop;
 567                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
 568         }
 569         if (np->rxopt.bits.odstopts && opt->dst0) {
 570                 u8 *ptr = nh + opt->dst0;
 571                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 572         }
 573         if (np->rxopt.bits.osrcrt && opt->srcrt) {
 574                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
 575                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
 576         }
 577         if (np->rxopt.bits.odstopts && opt->dst1) {
 578                 u8 *ptr = nh + opt->dst1;
 579                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 580         }
 581         if (np->rxopt.bits.rxorigdstaddr) {
 582                 struct sockaddr_in6 sin6;
 583                 __be16 *ports = (__be16 *) skb_transport_header(skb);
 584
 585                 if (skb_transport_offset(skb) + 4 <= skb->len) {
 586                         /* All current transport protocols have the port numbers in the
 587                          * first four bytes of the transport header and this function is
 588                          * written with this assumption in mind.
 589                          */
 590
 591                         sin6.sin6_family = AF_INET6;
 592                         sin6.sin6_addr = ipv6_hdr(skb)->daddr;
 593                         sin6.sin6_port = ports[1];
 594                         sin6.sin6_flowinfo = 0;
 595                         sin6.sin6_scope_id = 0;
 596
 597                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
 598                 }
 599         }
 600         return 0;
 601 }
 602 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);
 603
 604 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
 605                           struct msghdr *msg, struct flowi6 *fl6,
 606                           struct ipv6_txoptions *opt,
 607                           int *hlimit, int *tclass, int *dontfrag)
 608 {
 609         struct in6_pktinfo *src_info;
 610         struct cmsghdr *cmsg;
 611         struct ipv6_rt_hdr *rthdr;
 612         struct ipv6_opt_hdr *hdr;
 613         int len;
 614         int err = 0;
 615
 616         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 617                 int addr_type;
 618
 619                 if (!CMSG_OK(msg, cmsg)) {
 620                         err = -EINVAL;
 621                         goto exit_f;
 622                 }
 623
 624                 if (cmsg->cmsg_level != SOL_IPV6)
 625                         continue;
 626
 627                 switch (cmsg->cmsg_type) {
 628                 case IPV6_PKTINFO:
 629                 case IPV6_2292PKTINFO:
 630                     {
 631                         struct net_device *dev = NULL;
 632
 633                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 634                                 err = -EINVAL;
 635                                 goto exit_f;
 636                         }
 637
 638                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 639
 640                         if (src_info->ipi6_ifindex) {
 641                                 if (fl6->flowi6_oif &&
 642                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
 643                                         return -EINVAL;
 644                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
 645                         }
 646
 647                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 648
 649                         rcu_read_lock();
 650                         if (fl6->flowi6_oif) {
 651                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 652                                 if (!dev) {
 653                                         rcu_read_unlock();
 654                                         return -ENODEV;
 655                                 }
 656                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 657                                 rcu_read_unlock();
 658                                 return -EINVAL;
 659                         }
 660
 661                         if (addr_type != IPV6_ADDR_ANY) {
 662                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 663                                 if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
 664                                     !ipv6_chk_addr(net, &src_info->ipi6_addr,
 665                                                    strict ? dev : NULL, 0))
 666                                         err = -EINVAL;
 667                                 else
 668                                         fl6->saddr = src_info->ipi6_addr;
 669                         }
 670
 671                         rcu_read_unlock();
 672
 673                         if (err)
 674                                 goto exit_f;
 675
 676                         break;
 677                     }
 678
 679                 case IPV6_FLOWINFO:
 680                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
 681                                 err = -EINVAL;
 682                                 goto exit_f;
 683                         }
 684
 685                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 686                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 687                                         err = -EINVAL;
 688                                         goto exit_f;
 689                                 }
 690                         }
 691                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 692                         break;
 693
 694                 case IPV6_2292HOPOPTS:
 695                 case IPV6_HOPOPTS:
 696                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 697                                 err = -EINVAL;
 698                                 goto exit_f;
 699                         }
 700
 701                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 702                         len = ((hdr->hdrlen + 1) << 3);
 703                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 704                                 err = -EINVAL;
 705                                 goto exit_f;
 706                         }
 707                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 708                                 err = -EPERM;
 709                                 goto exit_f;
 710                         }
 711                         opt->opt_nflen += len;
 712                         opt->hopopt = hdr;
 713                         break;
 714
 715                 case IPV6_2292DSTOPTS:
 716                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 717                                 err = -EINVAL;
 718                                 goto exit_f;
 719                         }
 720
 721                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 722                         len = ((hdr->hdrlen + 1) << 3);
 723                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 724                                 err = -EINVAL;
 725                                 goto exit_f;
 726                         }
 727                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 728                                 err = -EPERM;
 729                                 goto exit_f;
 730                         }
 731                         if (opt->dst1opt) {
 732                                 err = -EINVAL;
 733                                 goto exit_f;
 734                         }
 735                         opt->opt_flen += len;
 736                         opt->dst1opt = hdr;
 737                         break;
 738
 739                 case IPV6_DSTOPTS:
 740                 case IPV6_RTHDRDSTOPTS:
 741                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 742                                 err = -EINVAL;
 743                                 goto exit_f;
 744                         }
 745
 746                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 747                         len = ((hdr->hdrlen + 1) << 3);
 748                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 749                                 err = -EINVAL;
 750                                 goto exit_f;
 751                         }
 752                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 753                                 err = -EPERM;
 754                                 goto exit_f;
 755                         }
 756                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 757                                 opt->opt_flen += len;
 758                                 opt->dst1opt = hdr;
 759                         } else {
 760                                 opt->opt_nflen += len;
 761                                 opt->dst0opt = hdr;
 762                         }
 763                         break;
 764
 765                 case IPV6_2292RTHDR:
 766                 case IPV6_RTHDR:
 767                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 768                                 err = -EINVAL;
 769                                 goto exit_f;
 770                         }
 771
 772                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
 773
 774                         switch (rthdr->type) {
 775 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 776                         case IPV6_SRCRT_TYPE_2:
 777                                 if (rthdr->hdrlen != 2 ||
 778                                     rthdr->segments_left != 1) {
 779                                         err = -EINVAL;
 780                                         goto exit_f;
 781                                 }
 782                                 break;
 783 #endif
 784                         default:
 785                                 err = -EINVAL;
 786                                 goto exit_f;
 787                         }
 788
 789                         len = ((rthdr->hdrlen + 1) << 3);
 790
 791                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 792                                 err = -EINVAL;
 793                                 goto exit_f;
 794                         }
 795
 796                         /* segments left must also match */
 797                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 798                                 err = -EINVAL;
 799                                 goto exit_f;
 800                         }
 801
 802                         opt->opt_nflen += len;
 803                         opt->srcrt = rthdr;
 804
 805                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 806                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
 807
 808                                 opt->opt_nflen += dsthdrlen;
 809                                 opt->dst0opt = opt->dst1opt;
 810                                 opt->dst1opt = NULL;
 811                                 opt->opt_flen -= dsthdrlen;
 812                         }
 813
 814                         break;
 815
 816                 case IPV6_2292HOPLIMIT:
 817                 case IPV6_HOPLIMIT:
 818                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 819                                 err = -EINVAL;
 820                                 goto exit_f;
 821                         }
 822
 823                         *hlimit = *(int *)CMSG_DATA(cmsg);
 824                         if (*hlimit < -1 || *hlimit > 0xff) {
 825                                 err = -EINVAL;
 826                                 goto exit_f;
 827                         }
 828
 829                         break;
 830
 831                 case IPV6_TCLASS:
 832                     {
 833                         int tc;
 834
 835                         err = -EINVAL;
 836                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 837                                 goto exit_f;
 838
 839                         tc = *(int *)CMSG_DATA(cmsg);
 840                         if (tc < -1 || tc > 0xff)
 841                                 goto exit_f;
 842
 843                         err = 0;
 844                         *tclass = tc;
 845
 846                         break;
 847                     }
 848
 849                 case IPV6_DONTFRAG:
 850                     {
 851                         int df;
 852
 853                         err = -EINVAL;
 854                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 855                                 goto exit_f;
 856
 857                         df = *(int *)CMSG_DATA(cmsg);
 858                         if (df < 0 || df > 1)
 859                                 goto exit_f;
 860
 861                         err = 0;
 862                         *dontfrag = df;
 863
 864                         break;
 865                     }
 866                 default:
 867                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
 868                                        cmsg->cmsg_type);
 869                         err = -EINVAL;
 870                         goto exit_f;
 871                 }
 872         }
 873
 874 exit_f:
 875         return err;
 876 }
 877 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);