linux/net/ipv6/udp.c
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   1/*
   2 *      UDP over IPv6
   3 *      Linux INET6 implementation
   4 *
   5 *      Authors:
   6 *      Pedro Roque             <roque@di.fc.ul.pt>
   7 *
   8 *      Based on linux/ipv4/udp.c
   9 *
  10 *      Fixes:
  11 *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  12 *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  13 *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  14 *                                      a single port at the same time.
  15 *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
  16 *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/udp6 to seq_file.
  17 *
  18 *      This program is free software; you can redistribute it and/or
  19 *      modify it under the terms of the GNU General Public License
  20 *      as published by the Free Software Foundation; either version
  21 *      2 of the License, or (at your option) any later version.
  22 */
  23
  24#include <linux/errno.h>
  25#include <linux/types.h>
  26#include <linux/socket.h>
  27#include <linux/sockios.h>
  28#include <linux/net.h>
  29#include <linux/in6.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_arp.h>
  32#include <linux/ipv6.h>
  33#include <linux/icmpv6.h>
  34#include <linux/init.h>
  35#include <linux/module.h>
  36#include <linux/skbuff.h>
  37#include <linux/slab.h>
  38#include <asm/uaccess.h>
  39
  40#include <net/addrconf.h>
  41#include <net/ndisc.h>
  42#include <net/protocol.h>
  43#include <net/transp_v6.h>
  44#include <net/ip6_route.h>
  45#include <net/raw.h>
  46#include <net/tcp_states.h>
  47#include <net/ip6_checksum.h>
  48#include <net/xfrm.h>
  49#include <net/inet6_hashtables.h>
  50#include <net/busy_poll.h>
  51#include <net/sock_reuseport.h>
  52
  53#include <linux/proc_fs.h>
  54#include <linux/seq_file.h>
  55#include <trace/events/skb.h>
  56#include "udp_impl.h"
  57
  58static u32 udp6_ehashfn(const struct net *net,
  59                        const struct in6_addr *laddr,
  60                        const u16 lport,
  61                        const struct in6_addr *faddr,
  62                        const __be16 fport)
  63{
  64        static u32 udp6_ehash_secret __read_mostly;
  65        static u32 udp_ipv6_hash_secret __read_mostly;
  66
  67        u32 lhash, fhash;
  68
  69        net_get_random_once(&udp6_ehash_secret,
  70                            sizeof(udp6_ehash_secret));
  71        net_get_random_once(&udp_ipv6_hash_secret,
  72                            sizeof(udp_ipv6_hash_secret));
  73
  74        lhash = (__force u32)laddr->s6_addr32[3];
  75        fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
  76
  77        return __inet6_ehashfn(lhash, lport, fhash, fport,
  78                               udp_ipv6_hash_secret + net_hash_mix(net));
  79}
  80
  81static u32 udp6_portaddr_hash(const struct net *net,
  82                              const struct in6_addr *addr6,
  83                              unsigned int port)
  84{
  85        unsigned int hash, mix = net_hash_mix(net);
  86
  87        if (ipv6_addr_any(addr6))
  88                hash = jhash_1word(0, mix);
  89        else if (ipv6_addr_v4mapped(addr6))
  90                hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
  91        else
  92                hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);
  93
  94        return hash ^ port;
  95}
  96
  97int udp_v6_get_port(struct sock *sk, unsigned short snum)
  98{
  99        unsigned int hash2_nulladdr =
 100                udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
 101        unsigned int hash2_partial =
 102                udp6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
 103
 104        /* precompute partial secondary hash */
 105        udp_sk(sk)->udp_portaddr_hash = hash2_partial;
 106        return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
 107}
 108
 109static void udp_v6_rehash(struct sock *sk)
 110{
 111        u16 new_hash = udp6_portaddr_hash(sock_net(sk),
 112                                          &sk->sk_v6_rcv_saddr,
 113                                          inet_sk(sk)->inet_num);
 114
 115        udp_lib_rehash(sk, new_hash);
 116}
 117
 118static inline int compute_score(struct sock *sk, struct net *net,
 119                                unsigned short hnum,
 120                                const struct in6_addr *saddr, __be16 sport,
 121                                const struct in6_addr *daddr, __be16 dport,
 122                                int dif)
 123{
 124        int score;
 125        struct inet_sock *inet;
 126
 127        if (!net_eq(sock_net(sk), net) ||
 128            udp_sk(sk)->udp_port_hash != hnum ||
 129            sk->sk_family != PF_INET6)
 130                return -1;
 131
 132        score = 0;
 133        inet = inet_sk(sk);
 134
 135        if (inet->inet_dport) {
 136                if (inet->inet_dport != sport)
 137                        return -1;
 138                score++;
 139        }
 140
 141        if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 142                if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 143                        return -1;
 144                score++;
 145        }
 146
 147        if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
 148                if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
 149                        return -1;
 150                score++;
 151        }
 152
 153        if (sk->sk_bound_dev_if) {
 154                if (sk->sk_bound_dev_if != dif)
 155                        return -1;
 156                score++;
 157        }
 158
 159        if (sk->sk_incoming_cpu == raw_smp_processor_id())
 160                score++;
 161
 162        return score;
 163}
 164
 165static inline int compute_score2(struct sock *sk, struct net *net,
 166                                 const struct in6_addr *saddr, __be16 sport,
 167                                 const struct in6_addr *daddr,
 168                                 unsigned short hnum, int dif)
 169{
 170        int score;
 171        struct inet_sock *inet;
 172
 173        if (!net_eq(sock_net(sk), net) ||
 174            udp_sk(sk)->udp_port_hash != hnum ||
 175            sk->sk_family != PF_INET6)
 176                return -1;
 177
 178        if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 179                return -1;
 180
 181        score = 0;
 182        inet = inet_sk(sk);
 183
 184        if (inet->inet_dport) {
 185                if (inet->inet_dport != sport)
 186                        return -1;
 187                score++;
 188        }
 189
 190        if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
 191                if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
 192                        return -1;
 193                score++;
 194        }
 195
 196        if (sk->sk_bound_dev_if) {
 197                if (sk->sk_bound_dev_if != dif)
 198                        return -1;
 199                score++;
 200        }
 201
 202        if (sk->sk_incoming_cpu == raw_smp_processor_id())
 203                score++;
 204
 205        return score;
 206}
 207
 208/* called with read_rcu_lock() */
 209static struct sock *udp6_lib_lookup2(struct net *net,
 210                const struct in6_addr *saddr, __be16 sport,
 211                const struct in6_addr *daddr, unsigned int hnum, int dif,
 212                struct udp_hslot *hslot2, unsigned int slot2,
 213                struct sk_buff *skb)
 214{
 215        struct sock *sk, *result;
 216        struct hlist_nulls_node *node;
 217        int score, badness, matches = 0, reuseport = 0;
 218        bool select_ok = true;
 219        u32 hash = 0;
 220
 221begin:
 222        result = NULL;
 223        badness = -1;
 224        udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 225                score = compute_score2(sk, net, saddr, sport,
 226                                      daddr, hnum, dif);
 227                if (score > badness) {
 228                        result = sk;
 229                        badness = score;
 230                        reuseport = sk->sk_reuseport;
 231                        if (reuseport) {
 232                                hash = udp6_ehashfn(net, daddr, hnum,
 233                                                    saddr, sport);
 234                                if (select_ok) {
 235                                        struct sock *sk2;
 236
 237                                        sk2 = reuseport_select_sock(sk, hash, skb,
 238                                                        sizeof(struct udphdr));
 239                                        if (sk2) {
 240                                                result = sk2;
 241                                                select_ok = false;
 242                                                goto found;
 243                                        }
 244                                }
 245                                matches = 1;
 246                        }
 247                } else if (score == badness && reuseport) {
 248                        matches++;
 249                        if (reciprocal_scale(hash, matches) == 0)
 250                                result = sk;
 251                        hash = next_pseudo_random32(hash);
 252                }
 253        }
 254        /*
 255         * if the nulls value we got at the end of this lookup is
 256         * not the expected one, we must restart lookup.
 257         * We probably met an item that was moved to another chain.
 258         */
 259        if (get_nulls_value(node) != slot2)
 260                goto begin;
 261
 262        if (result) {
 263found:
 264                if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 265                        result = NULL;
 266                else if (unlikely(compute_score2(result, net, saddr, sport,
 267                                  daddr, hnum, dif) < badness)) {
 268                        sock_put(result);
 269                        goto begin;
 270                }
 271        }
 272        return result;
 273}
 274
 275struct sock *__udp6_lib_lookup(struct net *net,
 276                                      const struct in6_addr *saddr, __be16 sport,
 277                                      const struct in6_addr *daddr, __be16 dport,
 278                                      int dif, struct udp_table *udptable,
 279                                      struct sk_buff *skb)
 280{
 281        struct sock *sk, *result;
 282        struct hlist_nulls_node *node;
 283        unsigned short hnum = ntohs(dport);
 284        unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 285        struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 286        int score, badness, matches = 0, reuseport = 0;
 287        bool select_ok = true;
 288        u32 hash = 0;
 289
 290        rcu_read_lock();
 291        if (hslot->count > 10) {
 292                hash2 = udp6_portaddr_hash(net, daddr, hnum);
 293                slot2 = hash2 & udptable->mask;
 294                hslot2 = &udptable->hash2[slot2];
 295                if (hslot->count < hslot2->count)
 296                        goto begin;
 297
 298                result = udp6_lib_lookup2(net, saddr, sport,
 299                                          daddr, hnum, dif,
 300                                          hslot2, slot2, skb);
 301                if (!result) {
 302                        hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
 303                        slot2 = hash2 & udptable->mask;
 304                        hslot2 = &udptable->hash2[slot2];
 305                        if (hslot->count < hslot2->count)
 306                                goto begin;
 307
 308                        result = udp6_lib_lookup2(net, saddr, sport,
 309                                                  &in6addr_any, hnum, dif,
 310                                                  hslot2, slot2, skb);
 311                }
 312                rcu_read_unlock();
 313                return result;
 314        }
 315begin:
 316        result = NULL;
 317        badness = -1;
 318        sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 319                score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
 320                if (score > badness) {
 321                        result = sk;
 322                        badness = score;
 323                        reuseport = sk->sk_reuseport;
 324                        if (reuseport) {
 325                                hash = udp6_ehashfn(net, daddr, hnum,
 326                                                    saddr, sport);
 327                                if (select_ok) {
 328                                        struct sock *sk2;
 329
 330                                        sk2 = reuseport_select_sock(sk, hash, skb,
 331                                                        sizeof(struct udphdr));
 332                                        if (sk2) {
 333                                                result = sk2;
 334                                                select_ok = false;
 335                                                goto found;
 336                                        }
 337                                }
 338                                matches = 1;
 339                        }
 340                } else if (score == badness && reuseport) {
 341                        matches++;
 342                        if (reciprocal_scale(hash, matches) == 0)
 343                                result = sk;
 344                        hash = next_pseudo_random32(hash);
 345                }
 346        }
 347        /*
 348         * if the nulls value we got at the end of this lookup is
 349         * not the expected one, we must restart lookup.
 350         * We probably met an item that was moved to another chain.
 351         */
 352        if (get_nulls_value(node) != slot)
 353                goto begin;
 354
 355        if (result) {
 356found:
 357                if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 358                        result = NULL;
 359                else if (unlikely(compute_score(result, net, hnum, saddr, sport,
 360                                        daddr, dport, dif) < badness)) {
 361                        sock_put(result);
 362                        goto begin;
 363                }
 364        }
 365        rcu_read_unlock();
 366        return result;
 367}
 368EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
 369
 370static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
 371                                          __be16 sport, __be16 dport,
 372                                          struct udp_table *udptable)
 373{
 374        struct sock *sk;
 375        const struct ipv6hdr *iph = ipv6_hdr(skb);
 376
 377        sk = skb_steal_sock(skb);
 378        if (unlikely(sk))
 379                return sk;
 380        return __udp6_lib_lookup(dev_net(skb_dst(skb)->dev), &iph->saddr, sport,
 381                                 &iph->daddr, dport, inet6_iif(skb),
 382                                 udptable, skb);
 383}
 384
 385struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
 386                             const struct in6_addr *daddr, __be16 dport, int dif)
 387{
 388        return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table, NULL);
 389}
 390EXPORT_SYMBOL_GPL(udp6_lib_lookup);
 391
 392/*
 393 *      This should be easy, if there is something there we
 394 *      return it, otherwise we block.
 395 */
 396
 397int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 398                  int noblock, int flags, int *addr_len)
 399{
 400        struct ipv6_pinfo *np = inet6_sk(sk);
 401        struct inet_sock *inet = inet_sk(sk);
 402        struct sk_buff *skb;
 403        unsigned int ulen, copied;
 404        int peeked, off = 0;
 405        int err;
 406        int is_udplite = IS_UDPLITE(sk);
 407        bool checksum_valid = false;
 408        int is_udp4;
 409        bool slow;
 410
 411        if (flags & MSG_ERRQUEUE)
 412                return ipv6_recv_error(sk, msg, len, addr_len);
 413
 414        if (np->rxpmtu && np->rxopt.bits.rxpmtu)
 415                return ipv6_recv_rxpmtu(sk, msg, len, addr_len);
 416
 417try_again:
 418        skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
 419                                  &peeked, &off, &err);
 420        if (!skb)
 421                goto out;
 422
 423        ulen = skb->len - sizeof(struct udphdr);
 424        copied = len;
 425        if (copied > ulen)
 426                copied = ulen;
 427        else if (copied < ulen)
 428                msg->msg_flags |= MSG_TRUNC;
 429
 430        is_udp4 = (skb->protocol == htons(ETH_P_IP));
 431
 432        /*
 433         * If checksum is needed at all, try to do it while copying the
 434         * data.  If the data is truncated, or if we only want a partial
 435         * coverage checksum (UDP-Lite), do it before the copy.
 436         */
 437
 438        if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
 439                checksum_valid = !udp_lib_checksum_complete(skb);
 440                if (!checksum_valid)
 441                        goto csum_copy_err;
 442        }
 443
 444        if (checksum_valid || skb_csum_unnecessary(skb))
 445                err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
 446                                            msg, copied);
 447        else {
 448                err = skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
 449                if (err == -EINVAL)
 450                        goto csum_copy_err;
 451        }
 452        if (unlikely(err)) {
 453                trace_kfree_skb(skb, udpv6_recvmsg);
 454                if (!peeked) {
 455                        atomic_inc(&sk->sk_drops);
 456                        if (is_udp4)
 457                                UDP_INC_STATS_USER(sock_net(sk),
 458                                                   UDP_MIB_INERRORS,
 459                                                   is_udplite);
 460                        else
 461                                UDP6_INC_STATS_USER(sock_net(sk),
 462                                                    UDP_MIB_INERRORS,
 463                                                    is_udplite);
 464                }
 465                goto out_free;
 466        }
 467        if (!peeked) {
 468                if (is_udp4)
 469                        UDP_INC_STATS_USER(sock_net(sk),
 470                                        UDP_MIB_INDATAGRAMS, is_udplite);
 471                else
 472                        UDP6_INC_STATS_USER(sock_net(sk),
 473                                        UDP_MIB_INDATAGRAMS, is_udplite);
 474        }
 475
 476        sock_recv_ts_and_drops(msg, sk, skb);
 477
 478        /* Copy the address. */
 479        if (msg->msg_name) {
 480                DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 481                sin6->sin6_family = AF_INET6;
 482                sin6->sin6_port = udp_hdr(skb)->source;
 483                sin6->sin6_flowinfo = 0;
 484
 485                if (is_udp4) {
 486                        ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
 487                                               &sin6->sin6_addr);
 488                        sin6->sin6_scope_id = 0;
 489                } else {
 490                        sin6->sin6_addr = ipv6_hdr(skb)->saddr;
 491                        sin6->sin6_scope_id =
 492                                ipv6_iface_scope_id(&sin6->sin6_addr,
 493                                                    inet6_iif(skb));
 494                }
 495                *addr_len = sizeof(*sin6);
 496        }
 497
 498        if (np->rxopt.all)
 499                ip6_datagram_recv_common_ctl(sk, msg, skb);
 500
 501        if (is_udp4) {
 502                if (inet->cmsg_flags)
 503                        ip_cmsg_recv(msg, skb);
 504        } else {
 505                if (np->rxopt.all)
 506                        ip6_datagram_recv_specific_ctl(sk, msg, skb);
 507        }
 508
 509        err = copied;
 510        if (flags & MSG_TRUNC)
 511                err = ulen;
 512
 513out_free:
 514        skb_free_datagram_locked(sk, skb);
 515out:
 516        return err;
 517
 518csum_copy_err:
 519        slow = lock_sock_fast(sk);
 520        if (!skb_kill_datagram(sk, skb, flags)) {
 521                if (is_udp4) {
 522                        UDP_INC_STATS_USER(sock_net(sk),
 523                                        UDP_MIB_CSUMERRORS, is_udplite);
 524                        UDP_INC_STATS_USER(sock_net(sk),
 525                                        UDP_MIB_INERRORS, is_udplite);
 526                } else {
 527                        UDP6_INC_STATS_USER(sock_net(sk),
 528                                        UDP_MIB_CSUMERRORS, is_udplite);
 529                        UDP6_INC_STATS_USER(sock_net(sk),
 530                                        UDP_MIB_INERRORS, is_udplite);
 531                }
 532        }
 533        unlock_sock_fast(sk, slow);
 534
 535        /* starting over for a new packet, but check if we need to yield */
 536        cond_resched();
 537        msg->msg_flags &= ~MSG_TRUNC;
 538        goto try_again;
 539}
 540
 541void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 542                    u8 type, u8 code, int offset, __be32 info,
 543                    struct udp_table *udptable)
 544{
 545        struct ipv6_pinfo *np;
 546        const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 547        const struct in6_addr *saddr = &hdr->saddr;
 548        const struct in6_addr *daddr = &hdr->daddr;
 549        struct udphdr *uh = (struct udphdr *)(skb->data+offset);
 550        struct sock *sk;
 551        int harderr;
 552        int err;
 553        struct net *net = dev_net(skb->dev);
 554
 555        sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
 556                               inet6_iif(skb), udptable, skb);
 557        if (!sk) {
 558                ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 559                                   ICMP6_MIB_INERRORS);
 560                return;
 561        }
 562
 563        harderr = icmpv6_err_convert(type, code, &err);
 564        np = inet6_sk(sk);
 565
 566        if (type == ICMPV6_PKT_TOOBIG) {
 567                if (!ip6_sk_accept_pmtu(sk))
 568                        goto out;
 569                ip6_sk_update_pmtu(skb, sk, info);
 570                if (np->pmtudisc != IPV6_PMTUDISC_DONT)
 571                        harderr = 1;
 572        }
 573        if (type == NDISC_REDIRECT) {
 574                ip6_sk_redirect(skb, sk);
 575                goto out;
 576        }
 577
 578        if (!np->recverr) {
 579                if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 580                        goto out;
 581        } else {
 582                ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
 583        }
 584
 585        sk->sk_err = err;
 586        sk->sk_error_report(sk);
 587out:
 588        sock_put(sk);
 589}
 590
 591static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 592{
 593        int rc;
 594
 595        if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
 596                sock_rps_save_rxhash(sk, skb);
 597                sk_mark_napi_id(sk, skb);
 598                sk_incoming_cpu_update(sk);
 599        }
 600
 601        rc = sock_queue_rcv_skb(sk, skb);
 602        if (rc < 0) {
 603                int is_udplite = IS_UDPLITE(sk);
 604
 605                /* Note that an ENOMEM error is charged twice */
 606                if (rc == -ENOMEM)
 607                        UDP6_INC_STATS_BH(sock_net(sk),
 608                                        UDP_MIB_RCVBUFERRORS, is_udplite);
 609                UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 610                kfree_skb(skb);
 611                return -1;
 612        }
 613        return 0;
 614}
 615
 616static __inline__ void udpv6_err(struct sk_buff *skb,
 617                                 struct inet6_skb_parm *opt, u8 type,
 618                                 u8 code, int offset, __be32 info)
 619{
 620        __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
 621}
 622
 623static struct static_key udpv6_encap_needed __read_mostly;
 624void udpv6_encap_enable(void)
 625{
 626        if (!static_key_enabled(&udpv6_encap_needed))
 627                static_key_slow_inc(&udpv6_encap_needed);
 628}
 629EXPORT_SYMBOL(udpv6_encap_enable);
 630
 631int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 632{
 633        struct udp_sock *up = udp_sk(sk);
 634        int rc;
 635        int is_udplite = IS_UDPLITE(sk);
 636
 637        if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 638                goto drop;
 639
 640        if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
 641                int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
 642
 643                /*
 644                 * This is an encapsulation socket so pass the skb to
 645                 * the socket's udp_encap_rcv() hook. Otherwise, just
 646                 * fall through and pass this up the UDP socket.
 647                 * up->encap_rcv() returns the following value:
 648                 * =0 if skb was successfully passed to the encap
 649                 *    handler or was discarded by it.
 650                 * >0 if skb should be passed on to UDP.
 651                 * <0 if skb should be resubmitted as proto -N
 652                 */
 653
 654                /* if we're overly short, let UDP handle it */
 655                encap_rcv = ACCESS_ONCE(up->encap_rcv);
 656                if (skb->len > sizeof(struct udphdr) && encap_rcv) {
 657                        int ret;
 658
 659                        /* Verify checksum before giving to encap */
 660                        if (udp_lib_checksum_complete(skb))
 661                                goto csum_error;
 662
 663                        ret = encap_rcv(sk, skb);
 664                        if (ret <= 0) {
 665                                UDP_INC_STATS_BH(sock_net(sk),
 666                                                 UDP_MIB_INDATAGRAMS,
 667                                                 is_udplite);
 668                                return -ret;
 669                        }
 670                }
 671
 672                /* FALLTHROUGH -- it's a UDP Packet */
 673        }
 674
 675        /*
 676         * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
 677         */
 678        if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
 679
 680                if (up->pcrlen == 0) {          /* full coverage was set  */
 681                        net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
 682                                            UDP_SKB_CB(skb)->cscov, skb->len);
 683                        goto drop;
 684                }
 685                if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
 686                        net_dbg_ratelimited("UDPLITE6: coverage %d too small, need min %d\n",
 687                                            UDP_SKB_CB(skb)->cscov, up->pcrlen);
 688                        goto drop;
 689                }
 690        }
 691
 692        if (rcu_access_pointer(sk->sk_filter)) {
 693                if (udp_lib_checksum_complete(skb))
 694                        goto csum_error;
 695        }
 696
 697        if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
 698                UDP6_INC_STATS_BH(sock_net(sk),
 699                                  UDP_MIB_RCVBUFERRORS, is_udplite);
 700                goto drop;
 701        }
 702
 703        skb_dst_drop(skb);
 704
 705        bh_lock_sock(sk);
 706        rc = 0;
 707        if (!sock_owned_by_user(sk))
 708                rc = __udpv6_queue_rcv_skb(sk, skb);
 709        else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
 710                bh_unlock_sock(sk);
 711                goto drop;
 712        }
 713        bh_unlock_sock(sk);
 714
 715        return rc;
 716
 717csum_error:
 718        UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
 719drop:
 720        UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 721        atomic_inc(&sk->sk_drops);
 722        kfree_skb(skb);
 723        return -1;
 724}
 725
 726static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
 727                                   __be16 loc_port, const struct in6_addr *loc_addr,
 728                                   __be16 rmt_port, const struct in6_addr *rmt_addr,
 729                                   int dif, unsigned short hnum)
 730{
 731        struct inet_sock *inet = inet_sk(sk);
 732
 733        if (!net_eq(sock_net(sk), net))
 734                return false;
 735
 736        if (udp_sk(sk)->udp_port_hash != hnum ||
 737            sk->sk_family != PF_INET6 ||
 738            (inet->inet_dport && inet->inet_dport != rmt_port) ||
 739            (!ipv6_addr_any(&sk->sk_v6_daddr) &&
 740                    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
 741            (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif) ||
 742            (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 743                    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
 744                return false;
 745        if (!inet6_mc_check(sk, loc_addr, rmt_addr))
 746                return false;
 747        return true;
 748}
 749
 750static void flush_stack(struct sock **stack, unsigned int count,
 751                        struct sk_buff *skb, unsigned int final)
 752{
 753        struct sk_buff *skb1 = NULL;
 754        struct sock *sk;
 755        unsigned int i;
 756
 757        for (i = 0; i < count; i++) {
 758                sk = stack[i];
 759                if (likely(!skb1))
 760                        skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
 761                if (!skb1) {
 762                        atomic_inc(&sk->sk_drops);
 763                        UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
 764                                          IS_UDPLITE(sk));
 765                        UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
 766                                          IS_UDPLITE(sk));
 767                }
 768
 769                if (skb1 && udpv6_queue_rcv_skb(sk, skb1) <= 0)
 770                        skb1 = NULL;
 771                sock_put(sk);
 772        }
 773        if (unlikely(skb1))
 774                kfree_skb(skb1);
 775}
 776
 777static void udp6_csum_zero_error(struct sk_buff *skb)
 778{
 779        /* RFC 2460 section 8.1 says that we SHOULD log
 780         * this error. Well, it is reasonable.
 781         */
 782        net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
 783                            &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
 784                            &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
 785}
 786
 787/*
 788 * Note: called only from the BH handler context,
 789 * so we don't need to lock the hashes.
 790 */
 791static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 792                const struct in6_addr *saddr, const struct in6_addr *daddr,
 793                struct udp_table *udptable, int proto)
 794{
 795        struct sock *sk, *stack[256 / sizeof(struct sock *)];
 796        const struct udphdr *uh = udp_hdr(skb);
 797        struct hlist_nulls_node *node;
 798        unsigned short hnum = ntohs(uh->dest);
 799        struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
 800        int dif = inet6_iif(skb);
 801        unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node);
 802        unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
 803        bool inner_flushed = false;
 804
 805        if (use_hash2) {
 806                hash2_any = udp6_portaddr_hash(net, &in6addr_any, hnum) &
 807                            udp_table.mask;
 808                hash2 = udp6_portaddr_hash(net, daddr, hnum) & udp_table.mask;
 809start_lookup:
 810                hslot = &udp_table.hash2[hash2];
 811                offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
 812        }
 813
 814        spin_lock(&hslot->lock);
 815        sk_nulls_for_each_entry_offset(sk, node, &hslot->head, offset) {
 816                if (__udp_v6_is_mcast_sock(net, sk,
 817                                           uh->dest, daddr,
 818                                           uh->source, saddr,
 819                                           dif, hnum) &&
 820                    /* If zero checksum and no_check is not on for
 821                     * the socket then skip it.
 822                     */
 823                    (uh->check || udp_sk(sk)->no_check6_rx)) {
 824                        if (unlikely(count == ARRAY_SIZE(stack))) {
 825                                flush_stack(stack, count, skb, ~0);
 826                                inner_flushed = true;
 827                                count = 0;
 828                        }
 829                        stack[count++] = sk;
 830                        sock_hold(sk);
 831                }
 832        }
 833
 834        spin_unlock(&hslot->lock);
 835
 836        /* Also lookup *:port if we are using hash2 and haven't done so yet. */
 837        if (use_hash2 && hash2 != hash2_any) {
 838                hash2 = hash2_any;
 839                goto start_lookup;
 840        }
 841
 842        if (count) {
 843                flush_stack(stack, count, skb, count - 1);
 844        } else {
 845                if (!inner_flushed)
 846                        UDP6_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI,
 847                                          proto == IPPROTO_UDPLITE);
 848                consume_skb(skb);
 849        }
 850        return 0;
 851}
 852
 853int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 854                   int proto)
 855{
 856        struct net *net = dev_net(skb->dev);
 857        struct sock *sk;
 858        struct udphdr *uh;
 859        const struct in6_addr *saddr, *daddr;
 860        u32 ulen = 0;
 861
 862        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 863                goto discard;
 864
 865        saddr = &ipv6_hdr(skb)->saddr;
 866        daddr = &ipv6_hdr(skb)->daddr;
 867        uh = udp_hdr(skb);
 868
 869        ulen = ntohs(uh->len);
 870        if (ulen > skb->len)
 871                goto short_packet;
 872
 873        if (proto == IPPROTO_UDP) {
 874                /* UDP validates ulen. */
 875
 876                /* Check for jumbo payload */
 877                if (ulen == 0)
 878                        ulen = skb->len;
 879
 880                if (ulen < sizeof(*uh))
 881                        goto short_packet;
 882
 883                if (ulen < skb->len) {
 884                        if (pskb_trim_rcsum(skb, ulen))
 885                                goto short_packet;
 886                        saddr = &ipv6_hdr(skb)->saddr;
 887                        daddr = &ipv6_hdr(skb)->daddr;
 888                        uh = udp_hdr(skb);
 889                }
 890        }
 891
 892        if (udp6_csum_init(skb, uh, proto))
 893                goto csum_error;
 894
 895        /*
 896         *      Multicast receive code
 897         */
 898        if (ipv6_addr_is_multicast(daddr))
 899                return __udp6_lib_mcast_deliver(net, skb,
 900                                saddr, daddr, udptable, proto);
 901
 902        /* Unicast */
 903
 904        /*
 905         * check socket cache ... must talk to Alan about his plans
 906         * for sock caches... i'll skip this for now.
 907         */
 908        sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
 909        if (sk) {
 910                int ret;
 911
 912                if (!uh->check && !udp_sk(sk)->no_check6_rx) {
 913                        sock_put(sk);
 914                        udp6_csum_zero_error(skb);
 915                        goto csum_error;
 916                }
 917
 918                if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
 919                        skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
 920                                                 ip6_compute_pseudo);
 921
 922                ret = udpv6_queue_rcv_skb(sk, skb);
 923                sock_put(sk);
 924
 925                /* a return value > 0 means to resubmit the input */
 926                if (ret > 0)
 927                        return ret;
 928
 929                return 0;
 930        }
 931
 932        if (!uh->check) {
 933                udp6_csum_zero_error(skb);
 934                goto csum_error;
 935        }
 936
 937        if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 938                goto discard;
 939
 940        if (udp_lib_checksum_complete(skb))
 941                goto csum_error;
 942
 943        UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
 944        icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 945
 946        kfree_skb(skb);
 947        return 0;
 948
 949short_packet:
 950        net_dbg_ratelimited("UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
 951                            proto == IPPROTO_UDPLITE ? "-Lite" : "",
 952                            saddr, ntohs(uh->source),
 953                            ulen, skb->len,
 954                            daddr, ntohs(uh->dest));
 955        goto discard;
 956csum_error:
 957        UDP6_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
 958discard:
 959        UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
 960        kfree_skb(skb);
 961        return 0;
 962}
 963
 964static __inline__ int udpv6_rcv(struct sk_buff *skb)
 965{
 966        return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
 967}
 968
 969/*
 970 * Throw away all pending data and cancel the corking. Socket is locked.
 971 */
 972static void udp_v6_flush_pending_frames(struct sock *sk)
 973{
 974        struct udp_sock *up = udp_sk(sk);
 975
 976        if (up->pending == AF_INET)
 977                udp_flush_pending_frames(sk);
 978        else if (up->pending) {
 979                up->len = 0;
 980                up->pending = 0;
 981                ip6_flush_pending_frames(sk);
 982        }
 983}
 984
 985/**
 986 *      udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
 987 *      @sk:    socket we are sending on
 988 *      @skb:   sk_buff containing the filled-in UDP header
 989 *              (checksum field must be zeroed out)
 990 */
 991static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
 992                                 const struct in6_addr *saddr,
 993                                 const struct in6_addr *daddr, int len)
 994{
 995        unsigned int offset;
 996        struct udphdr *uh = udp_hdr(skb);
 997        struct sk_buff *frags = skb_shinfo(skb)->frag_list;
 998        __wsum csum = 0;
 999
1000        if (!frags) {
1001                /* Only one fragment on the socket.  */
1002                skb->csum_start = skb_transport_header(skb) - skb->head;
1003                skb->csum_offset = offsetof(struct udphdr, check);
1004                uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
1005        } else {
1006                /*
1007                 * HW-checksum won't work as there are two or more
1008                 * fragments on the socket so that all csums of sk_buffs
1009                 * should be together
1010                 */
1011                offset = skb_transport_offset(skb);
1012                skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
1013
1014                skb->ip_summed = CHECKSUM_NONE;
1015
1016                do {
1017                        csum = csum_add(csum, frags->csum);
1018                } while ((frags = frags->next));
1019
1020                uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
1021                                            csum);
1022                if (uh->check == 0)
1023                        uh->check = CSUM_MANGLED_0;
1024        }
1025}
1026
1027/*
1028 *      Sending
1029 */
1030
1031static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
1032{
1033        struct sock *sk = skb->sk;
1034        struct udphdr *uh;
1035        int err = 0;
1036        int is_udplite = IS_UDPLITE(sk);
1037        __wsum csum = 0;
1038        int offset = skb_transport_offset(skb);
1039        int len = skb->len - offset;
1040
1041        /*
1042         * Create a UDP header
1043         */
1044        uh = udp_hdr(skb);
1045        uh->source = fl6->fl6_sport;
1046        uh->dest = fl6->fl6_dport;
1047        uh->len = htons(len);
1048        uh->check = 0;
1049
1050        if (is_udplite)
1051                csum = udplite_csum(skb);
1052        else if (udp_sk(sk)->no_check6_tx) {   /* UDP csum disabled */
1053                skb->ip_summed = CHECKSUM_NONE;
1054                goto send;
1055        } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
1056                udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
1057                goto send;
1058        } else
1059                csum = udp_csum(skb);
1060
1061        /* add protocol-dependent pseudo-header */
1062        uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
1063                                    len, fl6->flowi6_proto, csum);
1064        if (uh->check == 0)
1065                uh->check = CSUM_MANGLED_0;
1066
1067send:
1068        err = ip6_send_skb(skb);
1069        if (err) {
1070                if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
1071                        UDP6_INC_STATS_USER(sock_net(sk),
1072                                            UDP_MIB_SNDBUFERRORS, is_udplite);
1073                        err = 0;
1074                }
1075        } else
1076                UDP6_INC_STATS_USER(sock_net(sk),
1077                                    UDP_MIB_OUTDATAGRAMS, is_udplite);
1078        return err;
1079}
1080
1081static int udp_v6_push_pending_frames(struct sock *sk)
1082{
1083        struct sk_buff *skb;
1084        struct udp_sock  *up = udp_sk(sk);
1085        struct flowi6 fl6;
1086        int err = 0;
1087
1088        if (up->pending == AF_INET)
1089                return udp_push_pending_frames(sk);
1090
1091        /* ip6_finish_skb will release the cork, so make a copy of
1092         * fl6 here.
1093         */
1094        fl6 = inet_sk(sk)->cork.fl.u.ip6;
1095
1096        skb = ip6_finish_skb(sk);
1097        if (!skb)
1098                goto out;
1099
1100        err = udp_v6_send_skb(skb, &fl6);
1101
1102out:
1103        up->len = 0;
1104        up->pending = 0;
1105        return err;
1106}
1107
1108int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1109{
1110        struct ipv6_txoptions opt_space;
1111        struct udp_sock *up = udp_sk(sk);
1112        struct inet_sock *inet = inet_sk(sk);
1113        struct ipv6_pinfo *np = inet6_sk(sk);
1114        DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
1115        struct in6_addr *daddr, *final_p, final;
1116        struct ipv6_txoptions *opt = NULL;
1117        struct ipv6_txoptions *opt_to_free = NULL;
1118        struct ip6_flowlabel *flowlabel = NULL;
1119        struct flowi6 fl6;
1120        struct dst_entry *dst;
1121        int addr_len = msg->msg_namelen;
1122        int ulen = len;
1123        int hlimit = -1;
1124        int tclass = -1;
1125        int dontfrag = -1;
1126        int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
1127        int err;
1128        int connected = 0;
1129        int is_udplite = IS_UDPLITE(sk);
1130        int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1131
1132        /* destination address check */
1133        if (sin6) {
1134                if (addr_len < offsetof(struct sockaddr, sa_data))
1135                        return -EINVAL;
1136
1137                switch (sin6->sin6_family) {
1138                case AF_INET6:
1139                        if (addr_len < SIN6_LEN_RFC2133)
1140                                return -EINVAL;
1141                        daddr = &sin6->sin6_addr;
1142                        break;
1143                case AF_INET:
1144                        goto do_udp_sendmsg;
1145                case AF_UNSPEC:
1146                        msg->msg_name = sin6 = NULL;
1147                        msg->msg_namelen = addr_len = 0;
1148                        daddr = NULL;
1149                        break;
1150                default:
1151                        return -EINVAL;
1152                }
1153        } else if (!up->pending) {
1154                if (sk->sk_state != TCP_ESTABLISHED)
1155                        return -EDESTADDRREQ;
1156                daddr = &sk->sk_v6_daddr;
1157        } else
1158                daddr = NULL;
1159
1160        if (daddr) {
1161                if (ipv6_addr_v4mapped(daddr)) {
1162                        struct sockaddr_in sin;
1163                        sin.sin_family = AF_INET;
1164                        sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1165                        sin.sin_addr.s_addr = daddr->s6_addr32[3];
1166                        msg->msg_name = &sin;
1167                        msg->msg_namelen = sizeof(sin);
1168do_udp_sendmsg:
1169                        if (__ipv6_only_sock(sk))
1170                                return -ENETUNREACH;
1171                        return udp_sendmsg(sk, msg, len);
1172                }
1173        }
1174
1175        if (up->pending == AF_INET)
1176                return udp_sendmsg(sk, msg, len);
1177
1178        /* Rough check on arithmetic overflow,
1179           better check is made in ip6_append_data().
1180           */
1181        if (len > INT_MAX - sizeof(struct udphdr))
1182                return -EMSGSIZE;
1183
1184        getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1185        if (up->pending) {
1186                /*
1187                 * There are pending frames.
1188                 * The socket lock must be held while it's corked.
1189                 */
1190                lock_sock(sk);
1191                if (likely(up->pending)) {
1192                        if (unlikely(up->pending != AF_INET6)) {
1193                                release_sock(sk);
1194                                return -EAFNOSUPPORT;
1195                        }
1196                        dst = NULL;
1197                        goto do_append_data;
1198                }
1199                release_sock(sk);
1200        }
1201        ulen += sizeof(struct udphdr);
1202
1203        memset(&fl6, 0, sizeof(fl6));
1204
1205        if (sin6) {
1206                if (sin6->sin6_port == 0)
1207                        return -EINVAL;
1208
1209                fl6.fl6_dport = sin6->sin6_port;
1210                daddr = &sin6->sin6_addr;
1211
1212                if (np->sndflow) {
1213                        fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1214                        if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1215                                flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1216                                if (!flowlabel)
1217                                        return -EINVAL;
1218                        }
1219                }
1220
1221                /*
1222                 * Otherwise it will be difficult to maintain
1223                 * sk->sk_dst_cache.
1224                 */
1225                if (sk->sk_state == TCP_ESTABLISHED &&
1226                    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
1227                        daddr = &sk->sk_v6_daddr;
1228
1229                if (addr_len >= sizeof(struct sockaddr_in6) &&
1230                    sin6->sin6_scope_id &&
1231                    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
1232                        fl6.flowi6_oif = sin6->sin6_scope_id;
1233        } else {
1234                if (sk->sk_state != TCP_ESTABLISHED)
1235                        return -EDESTADDRREQ;
1236
1237                fl6.fl6_dport = inet->inet_dport;
1238                daddr = &sk->sk_v6_daddr;
1239                fl6.flowlabel = np->flow_label;
1240                connected = 1;
1241        }
1242
1243        if (!fl6.flowi6_oif)
1244                fl6.flowi6_oif = sk->sk_bound_dev_if;
1245
1246        if (!fl6.flowi6_oif)
1247                fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1248
1249        fl6.flowi6_mark = sk->sk_mark;
1250
1251        if (msg->msg_controllen) {
1252                opt = &opt_space;
1253                memset(opt, 0, sizeof(struct ipv6_txoptions));
1254                opt->tot_len = sizeof(*opt);
1255
1256                err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
1257                                            &hlimit, &tclass, &dontfrag);
1258                if (err < 0) {
1259                        fl6_sock_release(flowlabel);
1260                        return err;
1261                }
1262                if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1263                        flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1264                        if (!flowlabel)
1265                                return -EINVAL;
1266                }
1267                if (!(opt->opt_nflen|opt->opt_flen))
1268                        opt = NULL;
1269                connected = 0;
1270        }
1271        if (!opt) {
1272                opt = txopt_get(np);
1273                opt_to_free = opt;
1274        }
1275        if (flowlabel)
1276                opt = fl6_merge_options(&opt_space, flowlabel, opt);
1277        opt = ipv6_fixup_options(&opt_space, opt);
1278
1279        fl6.flowi6_proto = sk->sk_protocol;
1280        if (!ipv6_addr_any(daddr))
1281                fl6.daddr = *daddr;
1282        else
1283                fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1284        if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1285                fl6.saddr = np->saddr;
1286        fl6.fl6_sport = inet->inet_sport;
1287
1288        final_p = fl6_update_dst(&fl6, opt, &final);
1289        if (final_p)
1290                connected = 0;
1291
1292        if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1293                fl6.flowi6_oif = np->mcast_oif;
1294                connected = 0;
1295        } else if (!fl6.flowi6_oif)
1296                fl6.flowi6_oif = np->ucast_oif;
1297
1298        security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1299
1300        dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p);
1301        if (IS_ERR(dst)) {
1302                err = PTR_ERR(dst);
1303                dst = NULL;
1304                goto out;
1305        }
1306
1307        if (hlimit < 0)
1308                hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
1309
1310        if (tclass < 0)
1311                tclass = np->tclass;
1312
1313        if (msg->msg_flags&MSG_CONFIRM)
1314                goto do_confirm;
1315back_from_confirm:
1316
1317        /* Lockless fast path for the non-corking case */
1318        if (!corkreq) {
1319                struct sk_buff *skb;
1320
1321                skb = ip6_make_skb(sk, getfrag, msg, ulen,
1322                                   sizeof(struct udphdr), hlimit, tclass, opt,
1323                                   &fl6, (struct rt6_info *)dst,
1324                                   msg->msg_flags, dontfrag);
1325                err = PTR_ERR(skb);
1326                if (!IS_ERR_OR_NULL(skb))
1327                        err = udp_v6_send_skb(skb, &fl6);
1328                goto release_dst;
1329        }
1330
1331        lock_sock(sk);
1332        if (unlikely(up->pending)) {
1333                /* The socket is already corked while preparing it. */
1334                /* ... which is an evident application bug. --ANK */
1335                release_sock(sk);
1336
1337                net_dbg_ratelimited("udp cork app bug 2\n");
1338                err = -EINVAL;
1339                goto out;
1340        }
1341
1342        up->pending = AF_INET6;
1343
1344do_append_data:
1345        if (dontfrag < 0)
1346                dontfrag = np->dontfrag;
1347        up->len += ulen;
1348        err = ip6_append_data(sk, getfrag, msg, ulen,
1349                sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
1350                (struct rt6_info *)dst,
1351                corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
1352        if (err)
1353                udp_v6_flush_pending_frames(sk);
1354        else if (!corkreq)
1355                err = udp_v6_push_pending_frames(sk);
1356        else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1357                up->pending = 0;
1358
1359        if (err > 0)
1360                err = np->recverr ? net_xmit_errno(err) : 0;
1361        release_sock(sk);
1362
1363release_dst:
1364        if (dst) {
1365                if (connected) {
1366                        ip6_dst_store(sk, dst,
1367                                      ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
1368                                      &sk->sk_v6_daddr : NULL,
1369#ifdef CONFIG_IPV6_SUBTREES
1370                                      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1371                                      &np->saddr :
1372#endif
1373                                      NULL);
1374                } else {
1375                        dst_release(dst);
1376                }
1377                dst = NULL;
1378        }
1379
1380out:
1381        dst_release(dst);
1382        fl6_sock_release(flowlabel);
1383        txopt_put(opt_to_free);
1384        if (!err)
1385                return len;
1386        /*
1387         * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1388         * ENOBUFS might not be good (it's not tunable per se), but otherwise
1389         * we don't have a good statistic (IpOutDiscards but it can be too many
1390         * things).  We could add another new stat but at least for now that
1391         * seems like overkill.
1392         */
1393        if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1394                UDP6_INC_STATS_USER(sock_net(sk),
1395                                UDP_MIB_SNDBUFERRORS, is_udplite);
1396        }
1397        return err;
1398
1399do_confirm:
1400        dst_confirm(dst);
1401        if (!(msg->msg_flags&MSG_PROBE) || len)
1402                goto back_from_confirm;
1403        err = 0;
1404        goto out;
1405}
1406
1407void udpv6_destroy_sock(struct sock *sk)
1408{
1409        struct udp_sock *up = udp_sk(sk);
1410        lock_sock(sk);
1411        udp_v6_flush_pending_frames(sk);
1412        release_sock(sk);
1413
1414        if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
1415                void (*encap_destroy)(struct sock *sk);
1416                encap_destroy = ACCESS_ONCE(up->encap_destroy);
1417                if (encap_destroy)
1418                        encap_destroy(sk);
1419        }
1420
1421        inet6_destroy_sock(sk);
1422}
1423
1424/*
1425 *      Socket option code for UDP
1426 */
1427int udpv6_setsockopt(struct sock *sk, int level, int optname,
1428                     char __user *optval, unsigned int optlen)
1429{
1430        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1431                return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1432                                          udp_v6_push_pending_frames);
1433        return ipv6_setsockopt(sk, level, optname, optval, optlen);
1434}
1435
1436#ifdef CONFIG_COMPAT
1437int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1438                            char __user *optval, unsigned int optlen)
1439{
1440        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1441                return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1442                                          udp_v6_push_pending_frames);
1443        return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1444}
1445#endif
1446
1447int udpv6_getsockopt(struct sock *sk, int level, int optname,
1448                     char __user *optval, int __user *optlen)
1449{
1450        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1451                return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1452        return ipv6_getsockopt(sk, level, optname, optval, optlen);
1453}
1454
1455#ifdef CONFIG_COMPAT
1456int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1457                            char __user *optval, int __user *optlen)
1458{
1459        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1460                return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1461        return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1462}
1463#endif
1464
1465static const struct inet6_protocol udpv6_protocol = {
1466        .handler        =       udpv6_rcv,
1467        .err_handler    =       udpv6_err,
1468        .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1469};
1470
1471/* ------------------------------------------------------------------------ */
1472#ifdef CONFIG_PROC_FS
1473int udp6_seq_show(struct seq_file *seq, void *v)
1474{
1475        if (v == SEQ_START_TOKEN) {
1476                seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1477        } else {
1478                int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1479                struct inet_sock *inet = inet_sk(v);
1480                __u16 srcp = ntohs(inet->inet_sport);
1481                __u16 destp = ntohs(inet->inet_dport);
1482                ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
1483        }
1484        return 0;
1485}
1486
1487static const struct file_operations udp6_afinfo_seq_fops = {
1488        .owner    = THIS_MODULE,
1489        .open     = udp_seq_open,
1490        .read     = seq_read,
1491        .llseek   = seq_lseek,
1492        .release  = seq_release_net
1493};
1494
1495static struct udp_seq_afinfo udp6_seq_afinfo = {
1496        .name           = "udp6",
1497        .family         = AF_INET6,
1498        .udp_table      = &udp_table,
1499        .seq_fops       = &udp6_afinfo_seq_fops,
1500        .seq_ops        = {
1501                .show           = udp6_seq_show,
1502        },
1503};
1504
1505int __net_init udp6_proc_init(struct net *net)
1506{
1507        return udp_proc_register(net, &udp6_seq_afinfo);
1508}
1509
1510void udp6_proc_exit(struct net *net)
1511{
1512        udp_proc_unregister(net, &udp6_seq_afinfo);
1513}
1514#endif /* CONFIG_PROC_FS */
1515
1516void udp_v6_clear_sk(struct sock *sk, int size)
1517{
1518        struct inet_sock *inet = inet_sk(sk);
1519
1520        /* we do not want to clear pinet6 field, because of RCU lookups */
1521        sk_prot_clear_portaddr_nulls(sk, offsetof(struct inet_sock, pinet6));
1522
1523        size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1524        memset(&inet->pinet6 + 1, 0, size);
1525}
1526
1527/* ------------------------------------------------------------------------ */
1528
1529struct proto udpv6_prot = {
1530        .name              = "UDPv6",
1531        .owner             = THIS_MODULE,
1532        .close             = udp_lib_close,
1533        .connect           = ip6_datagram_connect,
1534        .disconnect        = udp_disconnect,
1535        .ioctl             = udp_ioctl,
1536        .destroy           = udpv6_destroy_sock,
1537        .setsockopt        = udpv6_setsockopt,
1538        .getsockopt        = udpv6_getsockopt,
1539        .sendmsg           = udpv6_sendmsg,
1540        .recvmsg           = udpv6_recvmsg,
1541        .backlog_rcv       = __udpv6_queue_rcv_skb,
1542        .release_cb        = ip6_datagram_release_cb,
1543        .hash              = udp_lib_hash,
1544        .unhash            = udp_lib_unhash,
1545        .rehash            = udp_v6_rehash,
1546        .get_port          = udp_v6_get_port,
1547        .memory_allocated  = &udp_memory_allocated,
1548        .sysctl_mem        = sysctl_udp_mem,
1549        .sysctl_wmem       = &sysctl_udp_wmem_min,
1550        .sysctl_rmem       = &sysctl_udp_rmem_min,
1551        .obj_size          = sizeof(struct udp6_sock),
1552        .slab_flags        = SLAB_DESTROY_BY_RCU,
1553        .h.udp_table       = &udp_table,
1554#ifdef CONFIG_COMPAT
1555        .compat_setsockopt = compat_udpv6_setsockopt,
1556        .compat_getsockopt = compat_udpv6_getsockopt,
1557#endif
1558        .clear_sk          = udp_v6_clear_sk,
1559};
1560
1561static struct inet_protosw udpv6_protosw = {
1562        .type =      SOCK_DGRAM,
1563        .protocol =  IPPROTO_UDP,
1564        .prot =      &udpv6_prot,
1565        .ops =       &inet6_dgram_ops,
1566        .flags =     INET_PROTOSW_PERMANENT,
1567};
1568
1569int __init udpv6_init(void)
1570{
1571        int ret;
1572
1573        ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1574        if (ret)
1575                goto out;
1576
1577        ret = inet6_register_protosw(&udpv6_protosw);
1578        if (ret)
1579                goto out_udpv6_protocol;
1580out:
1581        return ret;
1582
1583out_udpv6_protocol:
1584        inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1585        goto out;
1586}
1587
1588void udpv6_exit(void)
1589{
1590        inet6_unregister_protosw(&udpv6_protosw);
1591        inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1592}
1593