net/ipv6/datagram.c

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