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 (addr_type&IPV6_ADDR_LINKLOCAL) {
 128                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 129                     usin->sin6_scope_id) {
 130                         if (sk->sk_bound_dev_if &&
 131                             sk->sk_bound_dev_if != usin->sin6_scope_id) {
 132                                 err = -EINVAL;
 133                                 goto out;
 134                         }
 135                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 136                 }
 137
 138                 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
 139                         sk->sk_bound_dev_if = np->mcast_oif;
 140
 141                 /* Connect to link-local address requires an interface */
 142                 if (!sk->sk_bound_dev_if) {
 143                         err = -EINVAL;
 144                         goto out;
 145                 }
 146         }
 147
 148         np->daddr = *daddr;
 149         np->flow_label = fl6.flowlabel;
 150
 151         inet->inet_dport = usin->sin6_port;
 152
 153         /*
 154          *      Check for a route to destination an obtain the
 155          *      destination cache for it.
 156          */
 157
 158         fl6.flowi6_proto = sk->sk_protocol;
 159         fl6.daddr = np->daddr;
 160         fl6.saddr = np->saddr;
 161         fl6.flowi6_oif = sk->sk_bound_dev_if;
 162         fl6.flowi6_mark = sk->sk_mark;
 163         fl6.fl6_dport = inet->inet_dport;
 164         fl6.fl6_sport = inet->inet_sport;
 165
 166         if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 167                 fl6.flowi6_oif = np->mcast_oif;
 168
 169         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 170
 171         opt = flowlabel ? flowlabel->opt : np->opt;
 172         final_p = fl6_update_dst(&fl6, opt, &final);
 173
 174         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 175         err = 0;
 176         if (IS_ERR(dst)) {
 177                 err = PTR_ERR(dst);
 178                 goto out;
 179         }
 180
 181         /* source address lookup done in ip6_dst_lookup */
 182
 183         if (ipv6_addr_any(&np->saddr))
 184                 np->saddr = fl6.saddr;
 185
 186         if (ipv6_addr_any(&np->rcv_saddr)) {
 187                 np->rcv_saddr = fl6.saddr;
 188                 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 189                 if (sk->sk_prot->rehash)
 190                         sk->sk_prot->rehash(sk);
 191         }
 192
 193         ip6_dst_store(sk, dst,
 194                       ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
 195                       &np->daddr : NULL,
 196 #ifdef CONFIG_IPV6_SUBTREES
 197                       ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
 198                       &np->saddr :
 199 #endif
 200                       NULL);
 201
 202         sk->sk_state = TCP_ESTABLISHED;
 203 out:
 204         fl6_sock_release(flowlabel);
 205         return err;
 206 }
 207 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
 208
 209 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 210                      __be16 port, u32 info, u8 *payload)
 211 {
 212         struct ipv6_pinfo *np  = inet6_sk(sk);
 213         struct icmp6hdr *icmph = icmp6_hdr(skb);
 214         struct sock_exterr_skb *serr;
 215
 216         if (!np->recverr)
 217                 return;
 218
 219         skb = skb_clone(skb, GFP_ATOMIC);
 220         if (!skb)
 221                 return;
 222
 223         skb->protocol = htons(ETH_P_IPV6);
 224
 225         serr = SKB_EXT_ERR(skb);
 226         serr->ee.ee_errno = err;
 227         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 228         serr->ee.ee_type = icmph->icmp6_type;
 229         serr->ee.ee_code = icmph->icmp6_code;
 230         serr->ee.ee_pad = 0;
 231         serr->ee.ee_info = info;
 232         serr->ee.ee_data = 0;
 233         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
 234                                   skb_network_header(skb);
 235         serr->port = port;
 236
 237         __skb_pull(skb, payload - skb->data);
 238         skb_reset_transport_header(skb);
 239
 240         if (sock_queue_err_skb(sk, skb))
 241                 kfree_skb(skb);
 242 }
 243
 244 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 245 {
 246         struct ipv6_pinfo *np = inet6_sk(sk);
 247         struct sock_exterr_skb *serr;
 248         struct ipv6hdr *iph;
 249         struct sk_buff *skb;
 250
 251         if (!np->recverr)
 252                 return;
 253
 254         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 255         if (!skb)
 256                 return;
 257
 258         skb->protocol = htons(ETH_P_IPV6);
 259
 260         skb_put(skb, sizeof(struct ipv6hdr));
 261         skb_reset_network_header(skb);
 262         iph = ipv6_hdr(skb);
 263         iph->daddr = fl6->daddr;
 264
 265         serr = SKB_EXT_ERR(skb);
 266         serr->ee.ee_errno = err;
 267         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
 268         serr->ee.ee_type = 0;
 269         serr->ee.ee_code = 0;
 270         serr->ee.ee_pad = 0;
 271         serr->ee.ee_info = info;
 272         serr->ee.ee_data = 0;
 273         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 274         serr->port = fl6->fl6_dport;
 275
 276         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 277         skb_reset_transport_header(skb);
 278
 279         if (sock_queue_err_skb(sk, skb))
 280                 kfree_skb(skb);
 281 }
 282
 283 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 284 {
 285         struct ipv6_pinfo *np = inet6_sk(sk);
 286         struct ipv6hdr *iph;
 287         struct sk_buff *skb;
 288         struct ip6_mtuinfo *mtu_info;
 289
 290         if (!np->rxopt.bits.rxpmtu)
 291                 return;
 292
 293         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 294         if (!skb)
 295                 return;
 296
 297         skb_put(skb, sizeof(struct ipv6hdr));
 298         skb_reset_network_header(skb);
 299         iph = ipv6_hdr(skb);
 300         iph->daddr = fl6->daddr;
 301
 302         mtu_info = IP6CBMTU(skb);
 303
 304         mtu_info->ip6m_mtu = mtu;
 305         mtu_info->ip6m_addr.sin6_family = AF_INET6;
 306         mtu_info->ip6m_addr.sin6_port = 0;
 307         mtu_info->ip6m_addr.sin6_flowinfo = 0;
 308         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
 309         mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
 310
 311         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 312         skb_reset_transport_header(skb);
 313
 314         skb = xchg(&np->rxpmtu, skb);
 315         kfree_skb(skb);
 316 }
 317
 318 /*
 319  *      Handle MSG_ERRQUEUE
 320  */
 321 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
 322 {
 323         struct ipv6_pinfo *np = inet6_sk(sk);
 324         struct sock_exterr_skb *serr;
 325         struct sk_buff *skb, *skb2;
 326         struct sockaddr_in6 *sin;
 327         struct {
 328                 struct sock_extended_err ee;
 329                 struct sockaddr_in6      offender;
 330         } errhdr;
 331         int err;
 332         int copied;
 333
 334         err = -EAGAIN;
 335         skb = skb_dequeue(&sk->sk_error_queue);
 336         if (skb == NULL)
 337                 goto out;
 338
 339         copied = skb->len;
 340         if (copied > len) {
 341                 msg->msg_flags |= MSG_TRUNC;
 342                 copied = len;
 343         }
 344         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 345         if (err)
 346                 goto out_free_skb;
 347
 348         sock_recv_timestamp(msg, sk, skb);
 349
 350         serr = SKB_EXT_ERR(skb);
 351
 352         sin = (struct sockaddr_in6 *)msg->msg_name;
 353         if (sin) {
 354                 const unsigned char *nh = skb_network_header(skb);
 355                 sin->sin6_family = AF_INET6;
 356                 sin->sin6_flowinfo = 0;
 357                 sin->sin6_port = serr->port;
 358                 sin->sin6_scope_id = 0;
 359                 if (skb->protocol == htons(ETH_P_IPV6)) {
 360                         const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
 361                                                                   struct ipv6hdr, daddr);
 362                         sin->sin6_addr = ip6h->daddr;
 363                         if (np->sndflow)
 364                                 sin->sin6_flowinfo = ip6_flowinfo(ip6h);
 365                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 366                                 sin->sin6_scope_id = IP6CB(skb)->iif;
 367                 } else {
 368                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
 369                                                &sin->sin6_addr);
 370                 }
 371         }
 372
 373         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 374         sin = &errhdr.offender;
 375         sin->sin6_family = AF_UNSPEC;
 376         if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
 377                 sin->sin6_family = AF_INET6;
 378                 sin->sin6_flowinfo = 0;
 379                 sin->sin6_scope_id = 0;
 380                 if (skb->protocol == htons(ETH_P_IPV6)) {
 381                         sin->sin6_addr = ipv6_hdr(skb)->saddr;
 382                         if (np->rxopt.all)
 383                                 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_get_dsfield(ipv6_hdr(skb));
 492                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 493         }
 494
 495         if (np->rxopt.bits.rxflow) {
 496                 __be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
 497                 if (flowinfo)
 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
 602 int datagram_send_ctl(struct net *net, struct sock *sk,
 603                       struct msghdr *msg, struct flowi6 *fl6,
 604                       struct ipv6_txoptions *opt,
 605                       int *hlimit, int *tclass, int *dontfrag)
 606 {
 607         struct in6_pktinfo *src_info;
 608         struct cmsghdr *cmsg;
 609         struct ipv6_rt_hdr *rthdr;
 610         struct ipv6_opt_hdr *hdr;
 611         int len;
 612         int err = 0;
 613
 614         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 615                 int addr_type;
 616
 617                 if (!CMSG_OK(msg, cmsg)) {
 618                         err = -EINVAL;
 619                         goto exit_f;
 620                 }
 621
 622                 if (cmsg->cmsg_level != SOL_IPV6)
 623                         continue;
 624
 625                 switch (cmsg->cmsg_type) {
 626                 case IPV6_PKTINFO:
 627                 case IPV6_2292PKTINFO:
 628                     {
 629                         struct net_device *dev = NULL;
 630
 631                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 632                                 err = -EINVAL;
 633                                 goto exit_f;
 634                         }
 635
 636                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 637
 638                         if (src_info->ipi6_ifindex) {
 639                                 if (fl6->flowi6_oif &&
 640                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
 641                                         return -EINVAL;
 642                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
 643                         }
 644
 645                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 646
 647                         rcu_read_lock();
 648                         if (fl6->flowi6_oif) {
 649                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 650                                 if (!dev) {
 651                                         rcu_read_unlock();
 652                                         return -ENODEV;
 653                                 }
 654                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 655                                 rcu_read_unlock();
 656                                 return -EINVAL;
 657                         }
 658
 659                         if (addr_type != IPV6_ADDR_ANY) {
 660                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 661                                 if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
 662                                     !ipv6_chk_addr(net, &src_info->ipi6_addr,
 663                                                    strict ? dev : NULL, 0))
 664                                         err = -EINVAL;
 665                                 else
 666                                         fl6->saddr = src_info->ipi6_addr;
 667                         }
 668
 669                         rcu_read_unlock();
 670
 671                         if (err)
 672                                 goto exit_f;
 673
 674                         break;
 675                     }
 676
 677                 case IPV6_FLOWINFO:
 678                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
 679                                 err = -EINVAL;
 680                                 goto exit_f;
 681                         }
 682
 683                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 684                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 685                                         err = -EINVAL;
 686                                         goto exit_f;
 687                                 }
 688                         }
 689                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 690                         break;
 691
 692                 case IPV6_2292HOPOPTS:
 693                 case IPV6_HOPOPTS:
 694                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 695                                 err = -EINVAL;
 696                                 goto exit_f;
 697                         }
 698
 699                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 700                         len = ((hdr->hdrlen + 1) << 3);
 701                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 702                                 err = -EINVAL;
 703                                 goto exit_f;
 704                         }
 705                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 706                                 err = -EPERM;
 707                                 goto exit_f;
 708                         }
 709                         opt->opt_nflen += len;
 710                         opt->hopopt = hdr;
 711                         break;
 712
 713                 case IPV6_2292DSTOPTS:
 714                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 715                                 err = -EINVAL;
 716                                 goto exit_f;
 717                         }
 718
 719                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 720                         len = ((hdr->hdrlen + 1) << 3);
 721                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 722                                 err = -EINVAL;
 723                                 goto exit_f;
 724                         }
 725                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 726                                 err = -EPERM;
 727                                 goto exit_f;
 728                         }
 729                         if (opt->dst1opt) {
 730                                 err = -EINVAL;
 731                                 goto exit_f;
 732                         }
 733                         opt->opt_flen += len;
 734                         opt->dst1opt = hdr;
 735                         break;
 736
 737                 case IPV6_DSTOPTS:
 738                 case IPV6_RTHDRDSTOPTS:
 739                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 740                                 err = -EINVAL;
 741                                 goto exit_f;
 742                         }
 743
 744                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 745                         len = ((hdr->hdrlen + 1) << 3);
 746                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 747                                 err = -EINVAL;
 748                                 goto exit_f;
 749                         }
 750                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
 751                                 err = -EPERM;
 752                                 goto exit_f;
 753                         }
 754                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 755                                 opt->opt_flen += len;
 756                                 opt->dst1opt = hdr;
 757                         } else {
 758                                 opt->opt_nflen += len;
 759                                 opt->dst0opt = hdr;
 760                         }
 761                         break;
 762
 763                 case IPV6_2292RTHDR:
 764                 case IPV6_RTHDR:
 765                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 766                                 err = -EINVAL;
 767                                 goto exit_f;
 768                         }
 769
 770                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
 771
 772                         switch (rthdr->type) {
 773 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 774                         case IPV6_SRCRT_TYPE_2:
 775                                 if (rthdr->hdrlen != 2 ||
 776                                     rthdr->segments_left != 1) {
 777                                         err = -EINVAL;
 778                                         goto exit_f;
 779                                 }
 780                                 break;
 781 #endif
 782                         default:
 783                                 err = -EINVAL;
 784                                 goto exit_f;
 785                         }
 786
 787                         len = ((rthdr->hdrlen + 1) << 3);
 788
 789                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 790                                 err = -EINVAL;
 791                                 goto exit_f;
 792                         }
 793
 794                         /* segments left must also match */
 795                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 796                                 err = -EINVAL;
 797                                 goto exit_f;
 798                         }
 799
 800                         opt->opt_nflen += len;
 801                         opt->srcrt = rthdr;
 802
 803                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 804                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
 805
 806                                 opt->opt_nflen += dsthdrlen;
 807                                 opt->dst0opt = opt->dst1opt;
 808                                 opt->dst1opt = NULL;
 809                                 opt->opt_flen -= dsthdrlen;
 810                         }
 811
 812                         break;
 813
 814                 case IPV6_2292HOPLIMIT:
 815                 case IPV6_HOPLIMIT:
 816                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 817                                 err = -EINVAL;
 818                                 goto exit_f;
 819                         }
 820
 821                         *hlimit = *(int *)CMSG_DATA(cmsg);
 822                         if (*hlimit < -1 || *hlimit > 0xff) {
 823                                 err = -EINVAL;
 824                                 goto exit_f;
 825                         }
 826
 827                         break;
 828
 829                 case IPV6_TCLASS:
 830                     {
 831                         int tc;
 832
 833                         err = -EINVAL;
 834                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 835                                 goto exit_f;
 836
 837                         tc = *(int *)CMSG_DATA(cmsg);
 838                         if (tc < -1 || tc > 0xff)
 839                                 goto exit_f;
 840
 841                         err = 0;
 842                         *tclass = tc;
 843
 844                         break;
 845                     }
 846
 847                 case IPV6_DONTFRAG:
 848                     {
 849                         int df;
 850
 851                         err = -EINVAL;
 852                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
 853                                 goto exit_f;
 854
 855                         df = *(int *)CMSG_DATA(cmsg);
 856                         if (df < 0 || df > 1)
 857                                 goto exit_f;
 858
 859                         err = 0;
 860                         *dontfrag = df;
 861
 862                         break;
 863                     }
 864                 default:
 865                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
 866                                        cmsg->cmsg_type);
 867                         err = -EINVAL;
 868                         goto exit_f;
 869                 }
 870         }
 871
 872 exit_f:
 873         return err;
 874 }
 875 EXPORT_SYMBOL_GPL(datagram_send_ctl);