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 #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 (__ipv6_addr_needs_scope_id(addr_type)) {
 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         fl6.flowi6_uid = sock_i_uid(sk);
 166
 167         if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 168                 fl6.flowi6_oif = np->mcast_oif;
 169
 170         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 171
 172         opt = flowlabel ? flowlabel->opt : np->opt;
 173         final_p = fl6_update_dst(&fl6, opt, &final);
 174
 175         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 176         err = 0;
 177         if (IS_ERR(dst)) {
 178                 err = PTR_ERR(dst);
 179                 goto out;
 180         }
 181
 182         /* source address lookup done in ip6_dst_lookup */
 183
 184         if (ipv6_addr_any(&np->saddr))
 185                 np->saddr = fl6.saddr;
 186
 187         if (ipv6_addr_any(&np->rcv_saddr)) {
 188                 np->rcv_saddr = fl6.saddr;
 189                 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 190                 if (sk->sk_prot->rehash)
 191                         sk->sk_prot->rehash(sk);
 192         }
 193
 194         ip6_dst_store(sk, dst,
 195                       ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
 196                       &np->daddr : NULL,
 197 #ifdef CONFIG_IPV6_SUBTREES
 198                       ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
 199                       &np->saddr :
 200 #endif
 201                       NULL);
 202
 203         sk->sk_state = TCP_ESTABLISHED;
 204 out:
 205         fl6_sock_release(flowlabel);
 206         return err;
 207 }
 208 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
 209
 210 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 211                      __be16 port, u32 info, u8 *payload)
 212 {
 213         struct ipv6_pinfo *np  = inet6_sk(sk);
 214         struct icmp6hdr *icmph = icmp6_hdr(skb);
 215         struct sock_exterr_skb *serr;
 216
 217         if (!np->recverr)
 218                 return;
 219
 220         skb = skb_clone(skb, GFP_ATOMIC);
 221         if (!skb)
 222                 return;
 223
 224         skb->protocol = htons(ETH_P_IPV6);
 225
 226         serr = SKB_EXT_ERR(skb);
 227         serr->ee.ee_errno = err;
 228         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 229         serr->ee.ee_type = icmph->icmp6_type;
 230         serr->ee.ee_code = icmph->icmp6_code;
 231         serr->ee.ee_pad = 0;
 232         serr->ee.ee_info = info;
 233         serr->ee.ee_data = 0;
 234         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
 235                                   skb_network_header(skb);
 236         serr->port = port;
 237
 238         __skb_pull(skb, payload - skb->data);
 239         skb_reset_transport_header(skb);
 240
 241         if (sock_queue_err_skb(sk, skb))
 242                 kfree_skb(skb);
 243 }
 244
 245 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 246 {
 247         struct ipv6_pinfo *np = inet6_sk(sk);
 248         struct sock_exterr_skb *serr;
 249         struct ipv6hdr *iph;
 250         struct sk_buff *skb;
 251
 252         if (!np->recverr)
 253                 return;
 254
 255         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 256         if (!skb)
 257                 return;
 258
 259         skb->protocol = htons(ETH_P_IPV6);
 260
 261         skb_put(skb, sizeof(struct ipv6hdr));
 262         skb_reset_network_header(skb);
 263         iph = ipv6_hdr(skb);
 264         iph->daddr = fl6->daddr;
 265
 266         serr = SKB_EXT_ERR(skb);
 267         serr->ee.ee_errno = err;
 268         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
 269         serr->ee.ee_type = 0;
 270         serr->ee.ee_code = 0;
 271         serr->ee.ee_pad = 0;
 272         serr->ee.ee_info = info;
 273         serr->ee.ee_data = 0;
 274         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 275         serr->port = fl6->fl6_dport;
 276
 277         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 278         skb_reset_transport_header(skb);
 279
 280         if (sock_queue_err_skb(sk, skb))
 281                 kfree_skb(skb);
 282 }
 283
 284 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 285 {
 286         struct ipv6_pinfo *np = inet6_sk(sk);
 287         struct ipv6hdr *iph;
 288         struct sk_buff *skb;
 289         struct ip6_mtuinfo *mtu_info;
 290
 291         if (!np->rxopt.bits.rxpmtu)
 292                 return;
 293
 294         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 295         if (!skb)
 296                 return;
 297
 298         skb_put(skb, sizeof(struct ipv6hdr));
 299         skb_reset_network_header(skb);
 300         iph = ipv6_hdr(skb);
 301         iph->daddr = fl6->daddr;
 302
 303         mtu_info = IP6CBMTU(skb);
 304
 305         mtu_info->ip6m_mtu = mtu;
 306         mtu_info->ip6m_addr.sin6_family = AF_INET6;
 307         mtu_info->ip6m_addr.sin6_port = 0;
 308         mtu_info->ip6m_addr.sin6_flowinfo = 0;
 309         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
 310         mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
 311
 312         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 313         skb_reset_transport_header(skb);
 314
 315         skb = xchg(&np->rxpmtu, skb);
 316         kfree_skb(skb);
 317 }
 318
 319 /*
 320  *      Handle MSG_ERRQUEUE
 321  */
 322 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
 323 {
 324         struct ipv6_pinfo *np = inet6_sk(sk);
 325         struct sock_exterr_skb *serr;
 326         struct sk_buff *skb, *skb2;
 327         struct sockaddr_in6 *sin;
 328         struct {
 329                 struct sock_extended_err ee;
 330                 struct sockaddr_in6      offender;
 331         } errhdr;
 332         int err;
 333         int copied;
 334
 335         err = -EAGAIN;
 336         skb = skb_dequeue(&sk->sk_error_queue);
 337         if (skb == NULL)
 338                 goto out;
 339
 340         copied = skb->len;
 341         if (copied > len) {
 342                 msg->msg_flags |= MSG_TRUNC;
 343                 copied = len;
 344         }
 345         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 346         if (err)
 347                 goto out_free_skb;
 348
 349         sock_recv_timestamp(msg, sk, skb);
 350
 351         serr = SKB_EXT_ERR(skb);
 352
 353         sin = (struct sockaddr_in6 *)msg->msg_name;
 354         if (sin) {
 355                 const unsigned char *nh = skb_network_header(skb);
 356                 sin->sin6_family = AF_INET6;
 357                 sin->sin6_flowinfo = 0;
 358                 sin->sin6_port = serr->port;
 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                         sin->sin6_scope_id =
 366                                 ipv6_iface_scope_id(&sin->sin6_addr,
 367                                                     IP6CB(skb)->iif);
 368                 } else {
 369                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
 370                                                &sin->sin6_addr);
 371                         sin->sin6_scope_id = 0;
 372                 }
 373         }
 374
 375         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 376         sin = &errhdr.offender;
 377         sin->sin6_family = AF_UNSPEC;
 378         if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
 379                 sin->sin6_family = AF_INET6;
 380                 sin->sin6_flowinfo = 0;
 381                 if (skb->protocol == htons(ETH_P_IPV6)) {
 382                         sin->sin6_addr = ipv6_hdr(skb)->saddr;
 383                         if (np->rxopt.all)
 384                                 ip6_datagram_recv_ctl(sk, msg, skb);
 385                         sin->sin6_scope_id =
 386                                 ipv6_iface_scope_id(&sin->sin6_addr,
 387                                                     IP6CB(skb)->iif);
 388                 } else {
 389                         struct inet_sock *inet = inet_sk(sk);
 390
 391                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
 392                                                &sin->sin6_addr);
 393                         sin->sin6_scope_id = 0;
 394                         if (inet->cmsg_flags)
 395                                 ip_cmsg_recv(msg, skb);
 396                 }
 397         }
 398
 399         put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
 400
 401         /* Now we could try to dump offended packet options */
 402
 403         msg->msg_flags |= MSG_ERRQUEUE;
 404         err = copied;
 405
 406         /* Reset and regenerate socket error */
 407         spin_lock_bh(&sk->sk_error_queue.lock);
 408         sk->sk_err = 0;
 409         if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
 410                 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
 411                 spin_unlock_bh(&sk->sk_error_queue.lock);
 412                 sk->sk_error_report(sk);
 413         } else {
 414                 spin_unlock_bh(&sk->sk_error_queue.lock);
 415         }
 416
 417 out_free_skb:
 418         kfree_skb(skb);
 419 out:
 420         return err;
 421 }
 422 EXPORT_SYMBOL_GPL(ipv6_recv_error);
 423
 424 /*
 425  *      Handle IPV6_RECVPATHMTU
 426  */
 427 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
 428 {
 429         struct ipv6_pinfo *np = inet6_sk(sk);
 430         struct sk_buff *skb;
 431         struct sockaddr_in6 *sin;
 432         struct ip6_mtuinfo mtu_info;
 433         int err;
 434         int copied;
 435
 436         err = -EAGAIN;
 437         skb = xchg(&np->rxpmtu, NULL);
 438         if (skb == NULL)
 439                 goto out;
 440
 441         copied = skb->len;
 442         if (copied > len) {
 443                 msg->msg_flags |= MSG_TRUNC;
 444                 copied = len;
 445         }
 446         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 447         if (err)
 448                 goto out_free_skb;
 449
 450         sock_recv_timestamp(msg, sk, skb);
 451
 452         memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
 453
 454         sin = (struct sockaddr_in6 *)msg->msg_name;
 455         if (sin) {
 456                 sin->sin6_family = AF_INET6;
 457                 sin->sin6_flowinfo = 0;
 458                 sin->sin6_port = 0;
 459                 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
 460                 sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
 461         }
 462
 463         put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
 464
 465         err = copied;
 466
 467 out_free_skb:
 468         kfree_skb(skb);
 469 out:
 470         return err;
 471 }
 472
 473
 474 int ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
 475                           struct sk_buff *skb)
 476 {
 477         struct ipv6_pinfo *np = inet6_sk(sk);
 478         struct inet6_skb_parm *opt = IP6CB(skb);
 479         unsigned char *nh = skb_network_header(skb);
 480
 481         if (np->rxopt.bits.rxinfo) {
 482                 struct in6_pktinfo src_info;
 483
 484                 src_info.ipi6_ifindex = opt->iif;
 485                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 486                 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
 487         }
 488
 489         if (np->rxopt.bits.rxhlim) {
 490                 int hlim = ipv6_hdr(skb)->hop_limit;
 491                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
 492         }
 493
 494         if (np->rxopt.bits.rxtclass) {
 495                 int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 496                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 497         }
 498
 499         if (np->rxopt.bits.rxflow) {
 500                 __be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
 501                 if (flowinfo)
 502                         put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
 503         }
 504
 505         /* HbH is allowed only once */
 506         if (np->rxopt.bits.hopopts && opt->hop) {
 507                 u8 *ptr = nh + opt->hop;
 508                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
 509         }
 510
 511         if (opt->lastopt &&
 512             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
 513                 /*
 514                  * Silly enough, but we need to reparse in order to
 515                  * report extension headers (except for HbH)
 516                  * in order.
 517                  *
 518                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
 519                  * (and WILL NOT be) defined because
 520                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
 521                  */
 522                 unsigned int off = sizeof(struct ipv6hdr);
 523                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 524
 525                 while (off <= opt->lastopt) {
 526                         unsigned int len;
 527                         u8 *ptr = nh + off;
 528
 529                         switch (nexthdr) {
 530                         case IPPROTO_DSTOPTS:
 531                                 nexthdr = ptr[0];
 532                                 len = (ptr[1] + 1) << 3;
 533                                 if (np->rxopt.bits.dstopts)
 534                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
 535                                 break;
 536                         case IPPROTO_ROUTING:
 537                                 nexthdr = ptr[0];
 538                                 len = (ptr[1] + 1) << 3;
 539                                 if (np->rxopt.bits.srcrt)
 540                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
 541                                 break;
 542                         case IPPROTO_AH:
 543                                 nexthdr = ptr[0];
 544                                 len = (ptr[1] + 2) << 2;
 545                                 break;
 546                         default:
 547                                 nexthdr = ptr[0];
 548                                 len = (ptr[1] + 1) << 3;
 549                                 break;
 550                         }
 551
 552                         off += len;
 553                 }
 554         }
 555
 556         /* socket options in old style */
 557         if (np->rxopt.bits.rxoinfo) {
 558                 struct in6_pktinfo src_info;
 559
 560                 src_info.ipi6_ifindex = opt->iif;
 561                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 562                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
 563         }
 564         if (np->rxopt.bits.rxohlim) {
 565                 int hlim = ipv6_hdr(skb)->hop_limit;
 566                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
 567         }
 568         if (np->rxopt.bits.ohopopts && opt->hop) {
 569                 u8 *ptr = nh + opt->hop;
 570                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
 571         }
 572         if (np->rxopt.bits.odstopts && opt->dst0) {
 573                 u8 *ptr = nh + opt->dst0;
 574                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 575         }
 576         if (np->rxopt.bits.osrcrt && opt->srcrt) {
 577                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
 578                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
 579         }
 580         if (np->rxopt.bits.odstopts && opt->dst1) {
 581                 u8 *ptr = nh + opt->dst1;
 582                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 583         }
 584         if (np->rxopt.bits.rxorigdstaddr) {
 585                 struct sockaddr_in6 sin6;
 586                 __be16 *ports = (__be16 *) skb_transport_header(skb);
 587
 588                 if (skb_transport_offset(skb) + 4 <= skb->len) {
 589                         /* All current transport protocols have the port numbers in the
 590                          * first four bytes of the transport header and this function is
 591                          * written with this assumption in mind.
 592                          */
 593
 594                         sin6.sin6_family = AF_INET6;
 595                         sin6.sin6_addr = ipv6_hdr(skb)->daddr;
 596                         sin6.sin6_port = ports[1];
 597                         sin6.sin6_flowinfo = 0;
 598                         sin6.sin6_scope_id =
 599                                 ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
 600                                                     opt->iif);
 601
 602                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
 603                 }
 604         }
 605         return 0;
 606 }
 607 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);
 608
 609 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
 610                           struct msghdr *msg, struct flowi6 *fl6,
 611                           struct ipv6_txoptions *opt,
 612                           int *hlimit, int *tclass, int *dontfrag)
 613 {
 614         struct in6_pktinfo *src_info;
 615         struct cmsghdr *cmsg;
 616         struct ipv6_rt_hdr *rthdr;
 617         struct ipv6_opt_hdr *hdr;
 618         int len;
 619         int err = 0;
 620
 621         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 622                 int addr_type;
 623
 624                 if (!CMSG_OK(msg, cmsg)) {
 625                         err = -EINVAL;
 626                         goto exit_f;
 627                 }
 628
 629                 if (cmsg->cmsg_level != SOL_IPV6)
 630                         continue;
 631
 632                 switch (cmsg->cmsg_type) {
 633                 case IPV6_PKTINFO:
 634                 case IPV6_2292PKTINFO:
 635                     {
 636                         struct net_device *dev = NULL;
 637
 638                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 639                                 err = -EINVAL;
 640                                 goto exit_f;
 641                         }
 642
 643                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 644
 645                         if (src_info->ipi6_ifindex) {
 646                                 if (fl6->flowi6_oif &&
 647                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
 648                                         return -EINVAL;
 649                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
 650                         }
 651
 652                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 653
 654                         rcu_read_lock();
 655                         if (fl6->flowi6_oif) {
 656                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 657                                 if (!dev) {
 658                                         rcu_read_unlock();
 659                                         return -ENODEV;
 660                                 }
 661                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 662                                 rcu_read_unlock();
 663                                 return -EINVAL;
 664                         }
 665
 666                         if (addr_type != IPV6_ADDR_ANY) {
 667                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 668                                 if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
 669                                     !ipv6_chk_addr(net, &src_info->ipi6_addr,
 670                                                    strict ? dev : NULL, 0))
 671                                         err = -EINVAL;
 672                                 else
 673                                         fl6->saddr = src_info->ipi6_addr;
 674                         }
 675
 676                         rcu_read_unlock();
 677
 678                         if (err)
 679                                 goto exit_f;
 680
 681                         break;
 682                     }
 683
 684                 case IPV6_FLOWINFO:
 685                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
 686                                 err = -EINVAL;
 687                                 goto exit_f;
 688                         }
 689
 690                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 691                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 692                                         err = -EINVAL;
 693                                         goto exit_f;
 694                                 }
 695                         }
 696                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 697                         break;
 698
 699                 case IPV6_2292HOPOPTS:
 700                 case IPV6_HOPOPTS:
 701                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 702                                 err = -EINVAL;
 703                                 goto exit_f;
 704                         }
 705
 706                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 707                         len = ((hdr->hdrlen + 1) << 3);
 708                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 709                                 err = -EINVAL;
 710                                 goto exit_f;
 711                         }
 712                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 713                                 err = -EPERM;
 714                                 goto exit_f;
 715                         }
 716                         opt->opt_nflen += len;
 717                         opt->hopopt = hdr;
 718                         break;
 719
 720                 case IPV6_2292DSTOPTS:
 721                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 722                                 err = -EINVAL;
 723                                 goto exit_f;
 724                         }
 725
 726                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 727                         len = ((hdr->hdrlen + 1) << 3);
 728                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 729                                 err = -EINVAL;
 730                                 goto exit_f;
 731                         }
 732                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 733                                 err = -EPERM;
 734                                 goto exit_f;
 735                         }
 736                         if (opt->dst1opt) {
 737                                 err = -EINVAL;
 738                                 goto exit_f;
 739                         }
 740                         opt->opt_flen += len;
 741                         opt->dst1opt = hdr;
 742                         break;
 743
 744                 case IPV6_DSTOPTS:
 745                 case IPV6_RTHDRDSTOPTS:
 746                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 747                                 err = -EINVAL;
 748                                 goto exit_f;
 749                         }
 750
 751                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 752                         len = ((hdr->hdrlen + 1) << 3);
 753                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 754                                 err = -EINVAL;
 755                                 goto exit_f;
 756                         }
 757                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 758                                 err = -EPERM;
 759                                 goto exit_f;
 760                         }
 761                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 762                                 opt->opt_flen += len;
 763                                 opt->dst1opt = hdr;
 764                         } else {
 765                                 opt->opt_nflen += len;
 766                                 opt->dst0opt = hdr;
 767                         }
 768                         break;
 769
 770                 case IPV6_2292RTHDR:
 771                 case IPV6_RTHDR:
 772                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 773                                 err = -EINVAL;
 774                                 goto exit_f;
 775                         }
 776
 777                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
 778
 779                         switch (rthdr->type) {
 780 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 781                         case IPV6_SRCRT_TYPE_2:
 782                                 if (rthdr->hdrlen != 2 ||
 783                                     rthdr->segments_left != 1) {
 784                                         err = -EINVAL;
 785                                         goto exit_f;
 786                                 }
 787                                 break;
 788 #endif
 789                         default:
 790                                 err = -EINVAL;
 791                                 goto exit_f;
 792                         }
 793
 794                         len = ((rthdr->hdrlen + 1) << 3);
 795
 796                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 797                                 err = -EINVAL;
 798                                 goto exit_f;
 799                         }
 800
 801                         /* segments left must also match */
 802                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 803                                 err = -EINVAL;
 804                                 goto exit_f;
 805                         }
 806
 807                         opt->opt_nflen += len;
 808                         opt->srcrt = rthdr;
 809
 810                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 811                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
 812
 813                                 opt->opt_nflen += dsthdrlen;
 814                                 opt->dst0opt = opt->dst1opt;
 815                                 opt->dst1opt = NULL;
 816                                 opt->opt_flen -= dsthdrlen;
 817                         }
 818
 819                         break;
 820
 821                 case IPV6_2292HOPLIMIT:
 822                 case IPV6_HOPLIMIT:
 823                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 824                                 err = -EINVAL;
 825                                 goto exit_f;
 826                         }
 827
 828                         *hlimit = *(int *)CMSG_DATA(cmsg);
 829                         if (*hlimit < -1 || *hlimit > 0xff) {
 830                                 err = -EINVAL;
 831                                 goto exit_f;
 832                         }
 833
 834                         break;
 835
 836                 case IPV6_TCLASS:
 837                     {
 838                         int tc;
 839
 840                         err = -EINVAL;
 841                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 842                                 goto exit_f;
 843
 844                         tc = *(int *)CMSG_DATA(cmsg);
 845                         if (tc < -1 || tc > 0xff)
 846                                 goto exit_f;
 847
 848                         err = 0;
 849                         *tclass = tc;
 850
 851                         break;
 852                     }
 853
 854                 case IPV6_DONTFRAG:
 855                     {
 856                         int df;
 857
 858                         err = -EINVAL;
 859                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 860                                 goto exit_f;
 861
 862                         df = *(int *)CMSG_DATA(cmsg);
 863                         if (df < 0 || df > 1)
 864                                 goto exit_f;
 865
 866                         err = 0;
 867                         *dontfrag = df;
 868
 869                         break;
 870                     }
 871                 default:
 872                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
 873                                        cmsg->cmsg_type);
 874                         err = -EINVAL;
 875                         goto exit_f;
 876                 }
 877         }
 878
 879 exit_f:
 880         return err;
 881 }
 882 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);