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
  26 #include <net/ipv6.h>
  27 #include <net/ndisc.h>
  28 #include <net/addrconf.h>
  29 #include <net/transp_v6.h>
  30 #include <net/ip6_route.h>
  31 #include <net/tcp_states.h>
  32
  33 #include <linux/errqueue.h>
  34 #include <asm/uaccess.h>
  35
  36 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
  37 {
  38         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
  39         struct inet_sock        *inet = inet_sk(sk);
  40         struct ipv6_pinfo       *np = inet6_sk(sk);
  41         struct in6_addr         *daddr, *final_p, final;
  42         struct dst_entry        *dst;
  43         struct flowi6           fl6;
  44         struct ip6_flowlabel    *flowlabel = NULL;
  45         struct ipv6_txoptions   *opt;
  46         int                     addr_type;
  47         int                     err;
  48
  49         if (usin->sin6_family == AF_INET) {
  50                 if (__ipv6_only_sock(sk))
  51                         return -EAFNOSUPPORT;
  52                 err = ip4_datagram_connect(sk, uaddr, addr_len);
  53                 goto ipv4_connected;
  54         }
  55
  56         if (addr_len < SIN6_LEN_RFC2133)
  57                 return -EINVAL;
  58
  59         if (usin->sin6_family != AF_INET6)
  60                 return -EAFNOSUPPORT;
  61
  62         memset(&fl6, 0, sizeof(fl6));
  63         if (np->sndflow) {
  64                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
  65                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
  66                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
  67                         if (flowlabel == NULL)
  68                                 return -EINVAL;
  69                         ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
  70                 }
  71         }
  72
  73         addr_type = ipv6_addr_type(&usin->sin6_addr);
  74
  75         if (addr_type == IPV6_ADDR_ANY) {
  76                 /*
  77                  *      connect to self
  78                  */
  79                 usin->sin6_addr.s6_addr[15] = 0x01;
  80         }
  81
  82         daddr = &usin->sin6_addr;
  83
  84         if (addr_type == IPV6_ADDR_MAPPED) {
  85                 struct sockaddr_in sin;
  86
  87                 if (__ipv6_only_sock(sk)) {
  88                         err = -ENETUNREACH;
  89                         goto out;
  90                 }
  91                 sin.sin_family = AF_INET;
  92                 sin.sin_addr.s_addr = daddr->s6_addr32[3];
  93                 sin.sin_port = usin->sin6_port;
  94
  95                 err = ip4_datagram_connect(sk,
  96                                            (struct sockaddr*) &sin,
  97                                            sizeof(sin));
  98
  99 ipv4_connected:
 100                 if (err)
 101                         goto out;
 102
 103                 ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
 104
 105                 if (ipv6_addr_any(&np->saddr))
 106                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 107
 108                 if (ipv6_addr_any(&np->rcv_saddr)) {
 109                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 110                                                &np->rcv_saddr);
 111                         if (sk->sk_prot->rehash)
 112                                 sk->sk_prot->rehash(sk);
 113                 }
 114
 115                 goto out;
 116         }
 117
 118         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 119                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 120                     usin->sin6_scope_id) {
 121                         if (sk->sk_bound_dev_if &&
 122                             sk->sk_bound_dev_if != usin->sin6_scope_id) {
 123                                 err = -EINVAL;
 124                                 goto out;
 125                         }
 126                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 127                 }
 128
 129                 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
 130                         sk->sk_bound_dev_if = np->mcast_oif;
 131
 132                 /* Connect to link-local address requires an interface */
 133                 if (!sk->sk_bound_dev_if) {
 134                         err = -EINVAL;
 135                         goto out;
 136                 }
 137         }
 138
 139         ipv6_addr_copy(&np->daddr, daddr);
 140         np->flow_label = fl6.flowlabel;
 141
 142         inet->inet_dport = usin->sin6_port;
 143
 144         /*
 145          *      Check for a route to destination an obtain the
 146          *      destination cache for it.
 147          */
 148
 149         fl6.flowi6_proto = sk->sk_protocol;
 150         ipv6_addr_copy(&fl6.daddr, &np->daddr);
 151         ipv6_addr_copy(&fl6.saddr, &np->saddr);
 152         fl6.flowi6_oif = sk->sk_bound_dev_if;
 153         fl6.flowi6_mark = sk->sk_mark;
 154         fl6.fl6_dport = inet->inet_dport;
 155         fl6.fl6_sport = inet->inet_sport;
 156
 157         if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
 158                 fl6.flowi6_oif = np->mcast_oif;
 159
 160         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 161
 162         opt = flowlabel ? flowlabel->opt : np->opt;
 163         final_p = fl6_update_dst(&fl6, opt, &final);
 164
 165         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 166         err = 0;
 167         if (IS_ERR(dst)) {
 168                 err = PTR_ERR(dst);
 169                 goto out;
 170         }
 171
 172         /* source address lookup done in ip6_dst_lookup */
 173
 174         if (ipv6_addr_any(&np->saddr))
 175                 ipv6_addr_copy(&np->saddr, &fl6.saddr);
 176
 177         if (ipv6_addr_any(&np->rcv_saddr)) {
 178                 ipv6_addr_copy(&np->rcv_saddr, &fl6.saddr);
 179                 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 180                 if (sk->sk_prot->rehash)
 181                         sk->sk_prot->rehash(sk);
 182         }
 183
 184         ip6_dst_store(sk, dst,
 185                       ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
 186                       &np->daddr : NULL,
 187 #ifdef CONFIG_IPV6_SUBTREES
 188                       ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
 189                       &np->saddr :
 190 #endif
 191                       NULL);
 192
 193         sk->sk_state = TCP_ESTABLISHED;
 194 out:
 195         fl6_sock_release(flowlabel);
 196         return err;
 197 }
 198
 199 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 200                      __be16 port, u32 info, u8 *payload)
 201 {
 202         struct ipv6_pinfo *np  = inet6_sk(sk);
 203         struct icmp6hdr *icmph = icmp6_hdr(skb);
 204         struct sock_exterr_skb *serr;
 205
 206         if (!np->recverr)
 207                 return;
 208
 209         skb = skb_clone(skb, GFP_ATOMIC);
 210         if (!skb)
 211                 return;
 212
 213         skb->protocol = htons(ETH_P_IPV6);
 214
 215         serr = SKB_EXT_ERR(skb);
 216         serr->ee.ee_errno = err;
 217         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 218         serr->ee.ee_type = icmph->icmp6_type;
 219         serr->ee.ee_code = icmph->icmp6_code;
 220         serr->ee.ee_pad = 0;
 221         serr->ee.ee_info = info;
 222         serr->ee.ee_data = 0;
 223         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
 224                                   skb_network_header(skb);
 225         serr->port = port;
 226
 227         __skb_pull(skb, payload - skb->data);
 228         skb_reset_transport_header(skb);
 229
 230         if (sock_queue_err_skb(sk, skb))
 231                 kfree_skb(skb);
 232 }
 233
 234 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 235 {
 236         struct ipv6_pinfo *np = inet6_sk(sk);
 237         struct sock_exterr_skb *serr;
 238         struct ipv6hdr *iph;
 239         struct sk_buff *skb;
 240
 241         if (!np->recverr)
 242                 return;
 243
 244         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 245         if (!skb)
 246                 return;
 247
 248         skb->protocol = htons(ETH_P_IPV6);
 249
 250         skb_put(skb, sizeof(struct ipv6hdr));
 251         skb_reset_network_header(skb);
 252         iph = ipv6_hdr(skb);
 253         ipv6_addr_copy(&iph->daddr, &fl6->daddr);
 254
 255         serr = SKB_EXT_ERR(skb);
 256         serr->ee.ee_errno = err;
 257         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
 258         serr->ee.ee_type = 0;
 259         serr->ee.ee_code = 0;
 260         serr->ee.ee_pad = 0;
 261         serr->ee.ee_info = info;
 262         serr->ee.ee_data = 0;
 263         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 264         serr->port = fl6->fl6_dport;
 265
 266         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 267         skb_reset_transport_header(skb);
 268
 269         if (sock_queue_err_skb(sk, skb))
 270                 kfree_skb(skb);
 271 }
 272
 273 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 274 {
 275         struct ipv6_pinfo *np = inet6_sk(sk);
 276         struct ipv6hdr *iph;
 277         struct sk_buff *skb;
 278         struct ip6_mtuinfo *mtu_info;
 279
 280         if (!np->rxopt.bits.rxpmtu)
 281                 return;
 282
 283         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 284         if (!skb)
 285                 return;
 286
 287         skb_put(skb, sizeof(struct ipv6hdr));
 288         skb_reset_network_header(skb);
 289         iph = ipv6_hdr(skb);
 290         ipv6_addr_copy(&iph->daddr, &fl6->daddr);
 291
 292         mtu_info = IP6CBMTU(skb);
 293         if (!mtu_info) {
 294                 kfree_skb(skb);
 295                 return;
 296         }
 297
 298         mtu_info->ip6m_mtu = mtu;
 299         mtu_info->ip6m_addr.sin6_family = AF_INET6;
 300         mtu_info->ip6m_addr.sin6_port = 0;
 301         mtu_info->ip6m_addr.sin6_flowinfo = 0;
 302         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
 303         ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);
 304
 305         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
 306         skb_reset_transport_header(skb);
 307
 308         skb = xchg(&np->rxpmtu, skb);
 309         kfree_skb(skb);
 310 }
 311
 312 /*
 313  *      Handle MSG_ERRQUEUE
 314  */
 315 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
 316 {
 317         struct ipv6_pinfo *np = inet6_sk(sk);
 318         struct sock_exterr_skb *serr;
 319         struct sk_buff *skb, *skb2;
 320         struct sockaddr_in6 *sin;
 321         struct {
 322                 struct sock_extended_err ee;
 323                 struct sockaddr_in6      offender;
 324         } errhdr;
 325         int err;
 326         int copied;
 327
 328         err = -EAGAIN;
 329         skb = skb_dequeue(&sk->sk_error_queue);
 330         if (skb == NULL)
 331                 goto out;
 332
 333         copied = skb->len;
 334         if (copied > len) {
 335                 msg->msg_flags |= MSG_TRUNC;
 336                 copied = len;
 337         }
 338         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 339         if (err)
 340                 goto out_free_skb;
 341
 342         sock_recv_timestamp(msg, sk, skb);
 343
 344         serr = SKB_EXT_ERR(skb);
 345
 346         sin = (struct sockaddr_in6 *)msg->msg_name;
 347         if (sin) {
 348                 const unsigned char *nh = skb_network_header(skb);
 349                 sin->sin6_family = AF_INET6;
 350                 sin->sin6_flowinfo = 0;
 351                 sin->sin6_port = serr->port;
 352                 sin->sin6_scope_id = 0;
 353                 if (skb->protocol == htons(ETH_P_IPV6)) {
 354                         ipv6_addr_copy(&sin->sin6_addr,
 355                                   (struct in6_addr *)(nh + serr->addr_offset));
 356                         if (np->sndflow)
 357                                 sin->sin6_flowinfo =
 358                                         (*(__be32 *)(nh + serr->addr_offset - 24) &
 359                                          IPV6_FLOWINFO_MASK);
 360                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 361                                 sin->sin6_scope_id = IP6CB(skb)->iif;
 362                 } else {
 363                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
 364                                                &sin->sin6_addr);
 365                 }
 366         }
 367
 368         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 369         sin = &errhdr.offender;
 370         sin->sin6_family = AF_UNSPEC;
 371         if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
 372                 sin->sin6_family = AF_INET6;
 373                 sin->sin6_flowinfo = 0;
 374                 sin->sin6_scope_id = 0;
 375                 if (skb->protocol == htons(ETH_P_IPV6)) {
 376                         ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
 377                         if (np->rxopt.all)
 378                                 datagram_recv_ctl(sk, msg, skb);
 379                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 380                                 sin->sin6_scope_id = IP6CB(skb)->iif;
 381                 } else {
 382                         struct inet_sock *inet = inet_sk(sk);
 383
 384                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
 385                                                &sin->sin6_addr);
 386                         if (inet->cmsg_flags)
 387                                 ip_cmsg_recv(msg, skb);
 388                 }
 389         }
 390
 391         put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
 392
 393         /* Now we could try to dump offended packet options */
 394
 395         msg->msg_flags |= MSG_ERRQUEUE;
 396         err = copied;
 397
 398         /* Reset and regenerate socket error */
 399         spin_lock_bh(&sk->sk_error_queue.lock);
 400         sk->sk_err = 0;
 401         if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
 402                 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
 403                 spin_unlock_bh(&sk->sk_error_queue.lock);
 404                 sk->sk_error_report(sk);
 405         } else {
 406                 spin_unlock_bh(&sk->sk_error_queue.lock);
 407         }
 408
 409 out_free_skb:
 410         kfree_skb(skb);
 411 out:
 412         return err;
 413 }
 414
 415 /*
 416  *      Handle IPV6_RECVPATHMTU
 417  */
 418 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
 419 {
 420         struct ipv6_pinfo *np = inet6_sk(sk);
 421         struct sk_buff *skb;
 422         struct sockaddr_in6 *sin;
 423         struct ip6_mtuinfo mtu_info;
 424         int err;
 425         int copied;
 426
 427         err = -EAGAIN;
 428         skb = xchg(&np->rxpmtu, NULL);
 429         if (skb == NULL)
 430                 goto out;
 431
 432         copied = skb->len;
 433         if (copied > len) {
 434                 msg->msg_flags |= MSG_TRUNC;
 435                 copied = len;
 436         }
 437         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 438         if (err)
 439                 goto out_free_skb;
 440
 441         sock_recv_timestamp(msg, sk, skb);
 442
 443         memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
 444
 445         sin = (struct sockaddr_in6 *)msg->msg_name;
 446         if (sin) {
 447                 sin->sin6_family = AF_INET6;
 448                 sin->sin6_flowinfo = 0;
 449                 sin->sin6_port = 0;
 450                 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
 451                 ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);
 452         }
 453
 454         put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
 455
 456         err = copied;
 457
 458 out_free_skb:
 459         kfree_skb(skb);
 460 out:
 461         return err;
 462 }
 463
 464
 465 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
 466 {
 467         struct ipv6_pinfo *np = inet6_sk(sk);
 468         struct inet6_skb_parm *opt = IP6CB(skb);
 469         unsigned char *nh = skb_network_header(skb);
 470
 471         if (np->rxopt.bits.rxinfo) {
 472                 struct in6_pktinfo src_info;
 473
 474                 src_info.ipi6_ifindex = opt->iif;
 475                 ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
 476                 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
 477         }
 478
 479         if (np->rxopt.bits.rxhlim) {
 480                 int hlim = ipv6_hdr(skb)->hop_limit;
 481                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
 482         }
 483
 484         if (np->rxopt.bits.rxtclass) {
 485                 int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
 486                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
 487         }
 488
 489         if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
 490                 __be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
 491                 put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
 492         }
 493
 494         /* HbH is allowed only once */
 495         if (np->rxopt.bits.hopopts && opt->hop) {
 496                 u8 *ptr = nh + opt->hop;
 497                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
 498         }
 499
 500         if (opt->lastopt &&
 501             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
 502                 /*
 503                  * Silly enough, but we need to reparse in order to
 504                  * report extension headers (except for HbH)
 505                  * in order.
 506                  *
 507                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
 508                  * (and WILL NOT be) defined because
 509                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
 510                  */
 511                 unsigned int off = sizeof(struct ipv6hdr);
 512                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 513
 514                 while (off <= opt->lastopt) {
 515                         unsigned len;
 516                         u8 *ptr = nh + off;
 517
 518                         switch(nexthdr) {
 519                         case IPPROTO_DSTOPTS:
 520                                 nexthdr = ptr[0];
 521                                 len = (ptr[1] + 1) << 3;
 522                                 if (np->rxopt.bits.dstopts)
 523                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
 524                                 break;
 525                         case IPPROTO_ROUTING:
 526                                 nexthdr = ptr[0];
 527                                 len = (ptr[1] + 1) << 3;
 528                                 if (np->rxopt.bits.srcrt)
 529                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
 530                                 break;
 531                         case IPPROTO_AH:
 532                                 nexthdr = ptr[0];
 533                                 len = (ptr[1] + 2) << 2;
 534                                 break;
 535                         default:
 536                                 nexthdr = ptr[0];
 537                                 len = (ptr[1] + 1) << 3;
 538                                 break;
 539                         }
 540
 541                         off += len;
 542                 }
 543         }
 544
 545         /* socket options in old style */
 546         if (np->rxopt.bits.rxoinfo) {
 547                 struct in6_pktinfo src_info;
 548
 549                 src_info.ipi6_ifindex = opt->iif;
 550                 ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
 551                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
 552         }
 553         if (np->rxopt.bits.rxohlim) {
 554                 int hlim = ipv6_hdr(skb)->hop_limit;
 555                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
 556         }
 557         if (np->rxopt.bits.ohopopts && opt->hop) {
 558                 u8 *ptr = nh + opt->hop;
 559                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
 560         }
 561         if (np->rxopt.bits.odstopts && opt->dst0) {
 562                 u8 *ptr = nh + opt->dst0;
 563                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 564         }
 565         if (np->rxopt.bits.osrcrt && opt->srcrt) {
 566                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
 567                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
 568         }
 569         if (np->rxopt.bits.odstopts && opt->dst1) {
 570                 u8 *ptr = nh + opt->dst1;
 571                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
 572         }
 573         if (np->rxopt.bits.rxorigdstaddr) {
 574                 struct sockaddr_in6 sin6;
 575                 u16 *ports = (u16 *) skb_transport_header(skb);
 576
 577                 if (skb_transport_offset(skb) + 4 <= skb->len) {
 578                         /* All current transport protocols have the port numbers in the
 579                          * first four bytes of the transport header and this function is
 580                          * written with this assumption in mind.
 581                          */
 582
 583                         sin6.sin6_family = AF_INET6;
 584                         ipv6_addr_copy(&sin6.sin6_addr, &ipv6_hdr(skb)->daddr);
 585                         sin6.sin6_port = ports[1];
 586                         sin6.sin6_flowinfo = 0;
 587                         sin6.sin6_scope_id = 0;
 588
 589                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
 590                 }
 591         }
 592         return 0;
 593 }
 594
 595 int datagram_send_ctl(struct net *net,
 596                       struct msghdr *msg, struct flowi6 *fl6,
 597                       struct ipv6_txoptions *opt,
 598                       int *hlimit, int *tclass, int *dontfrag)
 599 {
 600         struct in6_pktinfo *src_info;
 601         struct cmsghdr *cmsg;
 602         struct ipv6_rt_hdr *rthdr;
 603         struct ipv6_opt_hdr *hdr;
 604         int len;
 605         int err = 0;
 606
 607         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 608                 int addr_type;
 609
 610                 if (!CMSG_OK(msg, cmsg)) {
 611                         err = -EINVAL;
 612                         goto exit_f;
 613                 }
 614
 615                 if (cmsg->cmsg_level != SOL_IPV6)
 616                         continue;
 617
 618                 switch (cmsg->cmsg_type) {
 619                 case IPV6_PKTINFO:
 620                 case IPV6_2292PKTINFO:
 621                     {
 622                         struct net_device *dev = NULL;
 623
 624                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
 625                                 err = -EINVAL;
 626                                 goto exit_f;
 627                         }
 628
 629                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 630
 631                         if (src_info->ipi6_ifindex) {
 632                                 if (fl6->flowi6_oif &&
 633                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
 634                                         return -EINVAL;
 635                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
 636                         }
 637
 638                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
 639
 640                         rcu_read_lock();
 641                         if (fl6->flowi6_oif) {
 642                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 643                                 if (!dev) {
 644                                         rcu_read_unlock();
 645                                         return -ENODEV;
 646                                 }
 647                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
 648                                 rcu_read_unlock();
 649                                 return -EINVAL;
 650                         }
 651
 652                         if (addr_type != IPV6_ADDR_ANY) {
 653                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
 654                                 if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
 655                                                    strict ? dev : NULL, 0))
 656                                         err = -EINVAL;
 657                                 else
 658                                         ipv6_addr_copy(&fl6->saddr, &src_info->ipi6_addr);
 659                         }
 660
 661                         rcu_read_unlock();
 662
 663                         if (err)
 664                                 goto exit_f;
 665
 666                         break;
 667                     }
 668
 669                 case IPV6_FLOWINFO:
 670                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
 671                                 err = -EINVAL;
 672                                 goto exit_f;
 673                         }
 674
 675                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
 676                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
 677                                         err = -EINVAL;
 678                                         goto exit_f;
 679                                 }
 680                         }
 681                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
 682                         break;
 683
 684                 case IPV6_2292HOPOPTS:
 685                 case IPV6_HOPOPTS:
 686                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 687                                 err = -EINVAL;
 688                                 goto exit_f;
 689                         }
 690
 691                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 692                         len = ((hdr->hdrlen + 1) << 3);
 693                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 694                                 err = -EINVAL;
 695                                 goto exit_f;
 696                         }
 697                         if (!capable(CAP_NET_RAW)) {
 698                                 err = -EPERM;
 699                                 goto exit_f;
 700                         }
 701                         opt->opt_nflen += len;
 702                         opt->hopopt = hdr;
 703                         break;
 704
 705                 case IPV6_2292DSTOPTS:
 706                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 707                                 err = -EINVAL;
 708                                 goto exit_f;
 709                         }
 710
 711                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 712                         len = ((hdr->hdrlen + 1) << 3);
 713                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 714                                 err = -EINVAL;
 715                                 goto exit_f;
 716                         }
 717                         if (!capable(CAP_NET_RAW)) {
 718                                 err = -EPERM;
 719                                 goto exit_f;
 720                         }
 721                         if (opt->dst1opt) {
 722                                 err = -EINVAL;
 723                                 goto exit_f;
 724                         }
 725                         opt->opt_flen += len;
 726                         opt->dst1opt = hdr;
 727                         break;
 728
 729                 case IPV6_DSTOPTS:
 730                 case IPV6_RTHDRDSTOPTS:
 731                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
 732                                 err = -EINVAL;
 733                                 goto exit_f;
 734                         }
 735
 736                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
 737                         len = ((hdr->hdrlen + 1) << 3);
 738                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 739                                 err = -EINVAL;
 740                                 goto exit_f;
 741                         }
 742                         if (!capable(CAP_NET_RAW)) {
 743                                 err = -EPERM;
 744                                 goto exit_f;
 745                         }
 746                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
 747                                 opt->opt_flen += len;
 748                                 opt->dst1opt = hdr;
 749                         } else {
 750                                 opt->opt_nflen += len;
 751                                 opt->dst0opt = hdr;
 752                         }
 753                         break;
 754
 755                 case IPV6_2292RTHDR:
 756                 case IPV6_RTHDR:
 757                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
 758                                 err = -EINVAL;
 759                                 goto exit_f;
 760                         }
 761
 762                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
 763
 764                         switch (rthdr->type) {
 765 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 766                         case IPV6_SRCRT_TYPE_2:
 767                                 if (rthdr->hdrlen != 2 ||
 768                                     rthdr->segments_left != 1) {
 769                                         err = -EINVAL;
 770                                         goto exit_f;
 771                                 }
 772                                 break;
 773 #endif
 774                         default:
 775                                 err = -EINVAL;
 776                                 goto exit_f;
 777                         }
 778
 779                         len = ((rthdr->hdrlen + 1) << 3);
 780
 781                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
 782                                 err = -EINVAL;
 783                                 goto exit_f;
 784                         }
 785
 786                         /* segments left must also match */
 787                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
 788                                 err = -EINVAL;
 789                                 goto exit_f;
 790                         }
 791
 792                         opt->opt_nflen += len;
 793                         opt->srcrt = rthdr;
 794
 795                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
 796                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
 797
 798                                 opt->opt_nflen += dsthdrlen;
 799                                 opt->dst0opt = opt->dst1opt;
 800                                 opt->dst1opt = NULL;
 801                                 opt->opt_flen -= dsthdrlen;
 802                         }
 803
 804                         break;
 805
 806                 case IPV6_2292HOPLIMIT:
 807                 case IPV6_HOPLIMIT:
 808                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 809                                 err = -EINVAL;
 810                                 goto exit_f;
 811                         }
 812
 813                         *hlimit = *(int *)CMSG_DATA(cmsg);
 814                         if (*hlimit < -1 || *hlimit > 0xff) {
 815                                 err = -EINVAL;
 816                                 goto exit_f;
 817                         }
 818
 819                         break;
 820
 821                 case IPV6_TCLASS:
 822                     {
 823                         int tc;
 824
 825                         err = -EINVAL;
 826                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 827                                 goto exit_f;
 828                         }
 829
 830                         tc = *(int *)CMSG_DATA(cmsg);
 831                         if (tc < -1 || tc > 0xff)
 832                                 goto exit_f;
 833
 834                         err = 0;
 835                         *tclass = tc;
 836
 837                         break;
 838                     }
 839
 840                 case IPV6_DONTFRAG:
 841                     {
 842                         int df;
 843
 844                         err = -EINVAL;
 845                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
 846                                 goto exit_f;
 847                         }
 848
 849                         df = *(int *)CMSG_DATA(cmsg);
 850                         if (df < 0 || df > 1)
 851                                 goto exit_f;
 852
 853                         err = 0;
 854                         *dontfrag = df;
 855
 856                         break;
 857                     }
 858                 default:
 859                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
 860                                        cmsg->cmsg_type);
 861                         err = -EINVAL;
 862                         goto exit_f;
 863                 }
 864         }
 865
 866 exit_f:
 867         return err;
 868 }