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                                 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 datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
 472 {
 473         struct ipv6_pinfo *np = inet6_sk(sk);
 474         struct inet6_skb_parm *opt = IP6CB(skb);
 475         unsigned char *nh = skb_network_header(skb);
 476
 477         if (np->rxopt.bits.rxinfo) {
 478                 struct in6_pktinfo src_info;
 479
 480                 src_info.ipi6_ifindex = opt->iif;
 481                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 482                 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
 483         }
 484
 485         if (np->rxopt.bits.rxhlim) {
 486                 int hlim = ipv6_hdr(skb)->hop_limit;
 487                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
 488         }
 489
 490         if (np->rxopt.bits.rxtclass) {
 491                 int tclass = ipv6_tclass(ipv6_hdr(skb));
 492                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 493         }
 494
 495         if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
 496                 __be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
 497                 put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
 498         }
 499
 500         /* HbH is allowed only once */
 501         if (np->rxopt.bits.hopopts && opt->hop) {
 502                 u8 *ptr = nh + opt->hop;
 503                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
 504         }
 505
 506         if (opt->lastopt &&
 507             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
 508                 /*
 509                  * Silly enough, but we need to reparse in order to
 510                  * report extension headers (except for HbH)
 511                  * in order.
 512                  *
 513                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
 514                  * (and WILL NOT be) defined because
 515                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
 516                  */
 517                 unsigned int off = sizeof(struct ipv6hdr);
 518                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 519
 520                 while (off <= opt->lastopt) {
 521                         unsigned int len;
 522                         u8 *ptr = nh + off;
 523
 524                         switch (nexthdr) {
 525                         case IPPROTO_DSTOPTS:
 526                                 nexthdr = ptr[0];
 527                                 len = (ptr[1] + 1) << 3;
 528                                 if (np->rxopt.bits.dstopts)
 529                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
 530                                 break;
 531                         case IPPROTO_ROUTING:
 532                                 nexthdr = ptr[0];
 533                                 len = (ptr[1] + 1) << 3;
 534                                 if (np->rxopt.bits.srcrt)
 535                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
 536                                 break;
 537                         case IPPROTO_AH:
 538                                 nexthdr = ptr[0];
 539                                 len = (ptr[1] + 2) << 2;
 540                                 break;
 541                         default:
 542                                 nexthdr = ptr[0];
 543                                 len = (ptr[1] + 1) << 3;
 544                                 break;
 545                         }
 546
 547                         off += len;
 548                 }
 549         }
 550
 551         /* socket options in old style */
 552         if (np->rxopt.bits.rxoinfo) {
 553                 struct in6_pktinfo src_info;
 554
 555                 src_info.ipi6_ifindex = opt->iif;
 556                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
 557                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
 558         }
 559         if (np->rxopt.bits.rxohlim) {
 560                 int hlim = ipv6_hdr(skb)->hop_limit;
 561                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
 562         }
 563         if (np->rxopt.bits.ohopopts && opt->hop) {
 564                 u8 *ptr = nh + opt->hop;
 565                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
 566         }
 567         if (np->rxopt.bits.odstopts && opt->dst0) {
 568                 u8 *ptr = nh + opt->dst0;
 569                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 570         }
 571         if (np->rxopt.bits.osrcrt && opt->srcrt) {
 572                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
 573                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
 574         }
 575         if (np->rxopt.bits.odstopts && opt->dst1) {
 576                 u8 *ptr = nh + opt->dst1;
 577                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 578         }
 579         if (np->rxopt.bits.rxorigdstaddr) {
 580                 struct sockaddr_in6 sin6;
 581                 __be16 *ports = (__be16 *) skb_transport_header(skb);
 582
 583                 if (skb_transport_offset(skb) + 4 <= skb->len) {
 584                         /* All current transport protocols have the port numbers in the
 585                          * first four bytes of the transport header and this function is
 586                          * written with this assumption in mind.
 587                          */
 588
 589                         sin6.sin6_family = AF_INET6;
 590                         sin6.sin6_addr = ipv6_hdr(skb)->daddr;
 591                         sin6.sin6_port = ports[1];
 592                         sin6.sin6_flowinfo = 0;
 593                         sin6.sin6_scope_id = 0;
 594
 595                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
 596                 }
 597         }
 598         return 0;
 599 }
 600
 601 int datagram_send_ctl(struct net *net, struct sock *sk,
 602                       struct msghdr *msg, struct flowi6 *fl6,
 603                       struct ipv6_txoptions *opt,
 604                       int *hlimit, int *tclass, int *dontfrag)
 605 {
 606         struct in6_pktinfo *src_info;
 607         struct cmsghdr *cmsg;
 608         struct ipv6_rt_hdr *rthdr;
 609         struct ipv6_opt_hdr *hdr;
 610         int len;
 611         int err = 0;
 612
 613         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 614                 int addr_type;
 615
 616                 if (!CMSG_OK(msg, cmsg)) {
 617                         err = -EINVAL;
 618                         goto exit_f;
 619                 }
 620
 621                 if (cmsg->cmsg_level != SOL_IPV6)
 622                         continue;
 623
 624                 switch (cmsg->cmsg_type) {
 625                 case IPV6_PKTINFO:
 626                 case IPV6_2292PKTINFO:
 627                     {
 628                         struct net_device *dev = NULL;
 629
 630                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 631                                 err = -EINVAL;
 632                                 goto exit_f;
 633                         }
 634
 635                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 636
 637                         if (src_info->ipi6_ifindex) {
 638                                 if (fl6->flowi6_oif &&
 639                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
 640                                         return -EINVAL;
 641                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
 642                         }
 643
 644                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 645
 646                         rcu_read_lock();
 647                         if (fl6->flowi6_oif) {
 648                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 649                                 if (!dev) {
 650                                         rcu_read_unlock();
 651                                         return -ENODEV;
 652                                 }
 653                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 654                                 rcu_read_unlock();
 655                                 return -EINVAL;
 656                         }
 657
 658                         if (addr_type != IPV6_ADDR_ANY) {
 659                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 660                                 if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
 661                                     !ipv6_chk_addr(net, &src_info->ipi6_addr,
 662                                                    strict ? dev : NULL, 0))
 663                                         err = -EINVAL;
 664                                 else
 665                                         fl6->saddr = src_info->ipi6_addr;
 666                         }
 667
 668                         rcu_read_unlock();
 669
 670                         if (err)
 671                                 goto exit_f;
 672
 673                         break;
 674                     }
 675
 676                 case IPV6_FLOWINFO:
 677                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
 678                                 err = -EINVAL;
 679                                 goto exit_f;
 680                         }
 681
 682                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 683                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 684                                         err = -EINVAL;
 685                                         goto exit_f;
 686                                 }
 687                         }
 688                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 689                         break;
 690
 691                 case IPV6_2292HOPOPTS:
 692                 case IPV6_HOPOPTS:
 693                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 694                                 err = -EINVAL;
 695                                 goto exit_f;
 696                         }
 697
 698                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 699                         len = ((hdr->hdrlen + 1) << 3);
 700                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 701                                 err = -EINVAL;
 702                                 goto exit_f;
 703                         }
 704                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 705                                 err = -EPERM;
 706                                 goto exit_f;
 707                         }
 708                         opt->opt_nflen += len;
 709                         opt->hopopt = hdr;
 710                         break;
 711
 712                 case IPV6_2292DSTOPTS:
 713                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 714                                 err = -EINVAL;
 715                                 goto exit_f;
 716                         }
 717
 718                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 719                         len = ((hdr->hdrlen + 1) << 3);
 720                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 721                                 err = -EINVAL;
 722                                 goto exit_f;
 723                         }
 724                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 725                                 err = -EPERM;
 726                                 goto exit_f;
 727                         }
 728                         if (opt->dst1opt) {
 729                                 err = -EINVAL;
 730                                 goto exit_f;
 731                         }
 732                         opt->opt_flen += len;
 733                         opt->dst1opt = hdr;
 734                         break;
 735
 736                 case IPV6_DSTOPTS:
 737                 case IPV6_RTHDRDSTOPTS:
 738                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 739                                 err = -EINVAL;
 740                                 goto exit_f;
 741                         }
 742
 743                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 744                         len = ((hdr->hdrlen + 1) << 3);
 745                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 746                                 err = -EINVAL;
 747                                 goto exit_f;
 748                         }
 749                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 750                                 err = -EPERM;
 751                                 goto exit_f;
 752                         }
 753                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 754                                 opt->opt_flen += len;
 755                                 opt->dst1opt = hdr;
 756                         } else {
 757                                 opt->opt_nflen += len;
 758                                 opt->dst0opt = hdr;
 759                         }
 760                         break;
 761
 762                 case IPV6_2292RTHDR:
 763                 case IPV6_RTHDR:
 764                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 765                                 err = -EINVAL;
 766                                 goto exit_f;
 767                         }
 768
 769                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
 770
 771                         switch (rthdr->type) {
 772 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 773                         case IPV6_SRCRT_TYPE_2:
 774                                 if (rthdr->hdrlen != 2 ||
 775                                     rthdr->segments_left != 1) {
 776                                         err = -EINVAL;
 777                                         goto exit_f;
 778                                 }
 779                                 break;
 780 #endif
 781                         default:
 782                                 err = -EINVAL;
 783                                 goto exit_f;
 784                         }
 785
 786                         len = ((rthdr->hdrlen + 1) << 3);
 787
 788                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 789                                 err = -EINVAL;
 790                                 goto exit_f;
 791                         }
 792
 793                         /* segments left must also match */
 794                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 795                                 err = -EINVAL;
 796                                 goto exit_f;
 797                         }
 798
 799                         opt->opt_nflen += len;
 800                         opt->srcrt = rthdr;
 801
 802                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 803                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
 804
 805                                 opt->opt_nflen += dsthdrlen;
 806                                 opt->dst0opt = opt->dst1opt;
 807                                 opt->dst1opt = NULL;
 808                                 opt->opt_flen -= dsthdrlen;
 809                         }
 810
 811                         break;
 812
 813                 case IPV6_2292HOPLIMIT:
 814                 case IPV6_HOPLIMIT:
 815                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 816                                 err = -EINVAL;
 817                                 goto exit_f;
 818                         }
 819
 820                         *hlimit = *(int *)CMSG_DATA(cmsg);
 821                         if (*hlimit < -1 || *hlimit > 0xff) {
 822                                 err = -EINVAL;
 823                                 goto exit_f;
 824                         }
 825
 826                         break;
 827
 828                 case IPV6_TCLASS:
 829                     {
 830                         int tc;
 831
 832                         err = -EINVAL;
 833                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 834                                 goto exit_f;
 835
 836                         tc = *(int *)CMSG_DATA(cmsg);
 837                         if (tc < -1 || tc > 0xff)
 838                                 goto exit_f;
 839
 840                         err = 0;
 841                         *tclass = tc;
 842
 843                         break;
 844                     }
 845
 846                 case IPV6_DONTFRAG:
 847                     {
 848                         int df;
 849
 850                         err = -EINVAL;
 851                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 852                                 goto exit_f;
 853
 854                         df = *(int *)CMSG_DATA(cmsg);
 855                         if (df < 0 || df > 1)
 856                                 goto exit_f;
 857
 858                         err = 0;
 859                         *dontfrag = df;
 860
 861                         break;
 862                     }
 863                 default:
 864                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
 865                                        cmsg->cmsg_type);
 866                         err = -EINVAL;
 867                         goto exit_f;
 868                 }
 869         }
 870
 871 exit_f:
 872         return err;
 873 }
 874 EXPORT_SYMBOL_GPL(datagram_send_ctl);