linux/net/ipv4/udp.c
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              The User Datagram Protocol (UDP).
   7 *
   8 * Authors:     Ross Biro
   9 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10 *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  11 *              Alan Cox, <alan@lxorguk.ukuu.org.uk>
  12 *              Hirokazu Takahashi, <taka@valinux.co.jp>
  13 *
  14 * Fixes:
  15 *              Alan Cox        :       verify_area() calls
  16 *              Alan Cox        :       stopped close while in use off icmp
  17 *                                      messages. Not a fix but a botch that
  18 *                                      for udp at least is 'valid'.
  19 *              Alan Cox        :       Fixed icmp handling properly
  20 *              Alan Cox        :       Correct error for oversized datagrams
  21 *              Alan Cox        :       Tidied select() semantics.
  22 *              Alan Cox        :       udp_err() fixed properly, also now
  23 *                                      select and read wake correctly on errors
  24 *              Alan Cox        :       udp_send verify_area moved to avoid mem leak
  25 *              Alan Cox        :       UDP can count its memory
  26 *              Alan Cox        :       send to an unknown connection causes
  27 *                                      an ECONNREFUSED off the icmp, but
  28 *                                      does NOT close.
  29 *              Alan Cox        :       Switched to new sk_buff handlers. No more backlog!
  30 *              Alan Cox        :       Using generic datagram code. Even smaller and the PEEK
  31 *                                      bug no longer crashes it.
  32 *              Fred Van Kempen :       Net2e support for sk->broadcast.
  33 *              Alan Cox        :       Uses skb_free_datagram
  34 *              Alan Cox        :       Added get/set sockopt support.
  35 *              Alan Cox        :       Broadcasting without option set returns EACCES.
  36 *              Alan Cox        :       No wakeup calls. Instead we now use the callbacks.
  37 *              Alan Cox        :       Use ip_tos and ip_ttl
  38 *              Alan Cox        :       SNMP Mibs
  39 *              Alan Cox        :       MSG_DONTROUTE, and 0.0.0.0 support.
  40 *              Matt Dillon     :       UDP length checks.
  41 *              Alan Cox        :       Smarter af_inet used properly.
  42 *              Alan Cox        :       Use new kernel side addressing.
  43 *              Alan Cox        :       Incorrect return on truncated datagram receive.
  44 *      Arnt Gulbrandsen        :       New udp_send and stuff
  45 *              Alan Cox        :       Cache last socket
  46 *              Alan Cox        :       Route cache
  47 *              Jon Peatfield   :       Minor efficiency fix to sendto().
  48 *              Mike Shaver     :       RFC1122 checks.
  49 *              Alan Cox        :       Nonblocking error fix.
  50 *      Willy Konynenberg       :       Transparent proxying support.
  51 *              Mike McLagan    :       Routing by source
  52 *              David S. Miller :       New socket lookup architecture.
  53 *                                      Last socket cache retained as it
  54 *                                      does have a high hit rate.
  55 *              Olaf Kirch      :       Don't linearise iovec on sendmsg.
  56 *              Andi Kleen      :       Some cleanups, cache destination entry
  57 *                                      for connect.
  58 *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
  59 *              Melvin Smith    :       Check msg_name not msg_namelen in sendto(),
  60 *                                      return ENOTCONN for unconnected sockets (POSIX)
  61 *              Janos Farkas    :       don't deliver multi/broadcasts to a different
  62 *                                      bound-to-device socket
  63 *      Hirokazu Takahashi      :       HW checksumming for outgoing UDP
  64 *                                      datagrams.
  65 *      Hirokazu Takahashi      :       sendfile() on UDP works now.
  66 *              Arnaldo C. Melo :       convert /proc/net/udp to seq_file
  67 *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  68 *      Alexey Kuznetsov:               allow both IPv4 and IPv6 sockets to bind
  69 *                                      a single port at the same time.
  70 *      Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
  71 *      James Chapman           :       Add L2TP encapsulation type.
  72 *
  73 *
  74 *              This program is free software; you can redistribute it and/or
  75 *              modify it under the terms of the GNU General Public License
  76 *              as published by the Free Software Foundation; either version
  77 *              2 of the License, or (at your option) any later version.
  78 */
  79
  80#define pr_fmt(fmt) "UDP: " fmt
  81
  82#include <asm/uaccess.h>
  83#include <asm/ioctls.h>
  84#include <linux/bootmem.h>
  85#include <linux/highmem.h>
  86#include <linux/swap.h>
  87#include <linux/types.h>
  88#include <linux/fcntl.h>
  89#include <linux/module.h>
  90#include <linux/socket.h>
  91#include <linux/sockios.h>
  92#include <linux/igmp.h>
  93#include <linux/in.h>
  94#include <linux/errno.h>
  95#include <linux/timer.h>
  96#include <linux/mm.h>
  97#include <linux/inet.h>
  98#include <linux/netdevice.h>
  99#include <linux/slab.h>
 100#include <net/tcp_states.h>
 101#include <linux/skbuff.h>
 102#include <linux/proc_fs.h>
 103#include <linux/seq_file.h>
 104#include <net/net_namespace.h>
 105#include <net/icmp.h>
 106#include <net/inet_hashtables.h>
 107#include <net/route.h>
 108#include <net/checksum.h>
 109#include <net/xfrm.h>
 110#include <trace/events/udp.h>
 111#include <linux/static_key.h>
 112#include <trace/events/skb.h>
 113#include <net/busy_poll.h>
 114#include "udp_impl.h"
 115
 116struct udp_table udp_table __read_mostly;
 117EXPORT_SYMBOL(udp_table);
 118
 119long sysctl_udp_mem[3] __read_mostly;
 120EXPORT_SYMBOL(sysctl_udp_mem);
 121
 122int sysctl_udp_rmem_min __read_mostly;
 123EXPORT_SYMBOL(sysctl_udp_rmem_min);
 124
 125int sysctl_udp_wmem_min __read_mostly;
 126EXPORT_SYMBOL(sysctl_udp_wmem_min);
 127
 128atomic_long_t udp_memory_allocated;
 129EXPORT_SYMBOL(udp_memory_allocated);
 130
 131#define MAX_UDP_PORTS 65536
 132#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
 133
 134static int udp_lib_lport_inuse(struct net *net, __u16 num,
 135                               const struct udp_hslot *hslot,
 136                               unsigned long *bitmap,
 137                               struct sock *sk,
 138                               int (*saddr_comp)(const struct sock *sk1,
 139                                                 const struct sock *sk2),
 140                               unsigned int log)
 141{
 142        struct sock *sk2;
 143        struct hlist_nulls_node *node;
 144        kuid_t uid = sock_i_uid(sk);
 145
 146        sk_nulls_for_each(sk2, node, &hslot->head)
 147                if (net_eq(sock_net(sk2), net) &&
 148                    sk2 != sk &&
 149                    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
 150                    (!sk2->sk_reuse || !sk->sk_reuse) &&
 151                    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 152                     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 153                    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 154                      !uid_eq(uid, sock_i_uid(sk2))) &&
 155                    (*saddr_comp)(sk, sk2)) {
 156                        if (bitmap)
 157                                __set_bit(udp_sk(sk2)->udp_port_hash >> log,
 158                                          bitmap);
 159                        else
 160                                return 1;
 161                }
 162        return 0;
 163}
 164
 165/*
 166 * Note: we still hold spinlock of primary hash chain, so no other writer
 167 * can insert/delete a socket with local_port == num
 168 */
 169static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 170                               struct udp_hslot *hslot2,
 171                               struct sock *sk,
 172                               int (*saddr_comp)(const struct sock *sk1,
 173                                                 const struct sock *sk2))
 174{
 175        struct sock *sk2;
 176        struct hlist_nulls_node *node;
 177        kuid_t uid = sock_i_uid(sk);
 178        int res = 0;
 179
 180        spin_lock(&hslot2->lock);
 181        udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
 182                if (net_eq(sock_net(sk2), net) &&
 183                    sk2 != sk &&
 184                    (udp_sk(sk2)->udp_port_hash == num) &&
 185                    (!sk2->sk_reuse || !sk->sk_reuse) &&
 186                    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 187                     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 188                    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 189                      !uid_eq(uid, sock_i_uid(sk2))) &&
 190                    (*saddr_comp)(sk, sk2)) {
 191                        res = 1;
 192                        break;
 193                }
 194        spin_unlock(&hslot2->lock);
 195        return res;
 196}
 197
 198/**
 199 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
 200 *
 201 *  @sk:          socket struct in question
 202 *  @snum:        port number to look up
 203 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
 204 *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
 205 *                   with NULL address
 206 */
 207int udp_lib_get_port(struct sock *sk, unsigned short snum,
 208                       int (*saddr_comp)(const struct sock *sk1,
 209                                         const struct sock *sk2),
 210                     unsigned int hash2_nulladdr)
 211{
 212        struct udp_hslot *hslot, *hslot2;
 213        struct udp_table *udptable = sk->sk_prot->h.udp_table;
 214        int    error = 1;
 215        struct net *net = sock_net(sk);
 216
 217        if (!snum) {
 218                int low, high, remaining;
 219                unsigned int rand;
 220                unsigned short first, last;
 221                DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
 222
 223                inet_get_local_port_range(net, &low, &high);
 224                remaining = (high - low) + 1;
 225
 226                rand = prandom_u32();
 227                first = (((u64)rand * remaining) >> 32) + low;
 228                /*
 229                 * force rand to be an odd multiple of UDP_HTABLE_SIZE
 230                 */
 231                rand = (rand | 1) * (udptable->mask + 1);
 232                last = first + udptable->mask + 1;
 233                do {
 234                        hslot = udp_hashslot(udptable, net, first);
 235                        bitmap_zero(bitmap, PORTS_PER_CHAIN);
 236                        spin_lock_bh(&hslot->lock);
 237                        udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
 238                                            saddr_comp, udptable->log);
 239
 240                        snum = first;
 241                        /*
 242                         * Iterate on all possible values of snum for this hash.
 243                         * Using steps of an odd multiple of UDP_HTABLE_SIZE
 244                         * give us randomization and full range coverage.
 245                         */
 246                        do {
 247                                if (low <= snum && snum <= high &&
 248                                    !test_bit(snum >> udptable->log, bitmap) &&
 249                                    !inet_is_local_reserved_port(net, snum))
 250                                        goto found;
 251                                snum += rand;
 252                        } while (snum != first);
 253                        spin_unlock_bh(&hslot->lock);
 254                } while (++first != last);
 255                goto fail;
 256        } else {
 257                hslot = udp_hashslot(udptable, net, snum);
 258                spin_lock_bh(&hslot->lock);
 259                if (hslot->count > 10) {
 260                        int exist;
 261                        unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
 262
 263                        slot2          &= udptable->mask;
 264                        hash2_nulladdr &= udptable->mask;
 265
 266                        hslot2 = udp_hashslot2(udptable, slot2);
 267                        if (hslot->count < hslot2->count)
 268                                goto scan_primary_hash;
 269
 270                        exist = udp_lib_lport_inuse2(net, snum, hslot2,
 271                                                     sk, saddr_comp);
 272                        if (!exist && (hash2_nulladdr != slot2)) {
 273                                hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
 274                                exist = udp_lib_lport_inuse2(net, snum, hslot2,
 275                                                             sk, saddr_comp);
 276                        }
 277                        if (exist)
 278                                goto fail_unlock;
 279                        else
 280                                goto found;
 281                }
 282scan_primary_hash:
 283                if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
 284                                        saddr_comp, 0))
 285                        goto fail_unlock;
 286        }
 287found:
 288        inet_sk(sk)->inet_num = snum;
 289        udp_sk(sk)->udp_port_hash = snum;
 290        udp_sk(sk)->udp_portaddr_hash ^= snum;
 291        if (sk_unhashed(sk)) {
 292                sk_nulls_add_node_rcu(sk, &hslot->head);
 293                hslot->count++;
 294                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 295
 296                hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 297                spin_lock(&hslot2->lock);
 298                hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
 299                                         &hslot2->head);
 300                hslot2->count++;
 301                spin_unlock(&hslot2->lock);
 302        }
 303        error = 0;
 304fail_unlock:
 305        spin_unlock_bh(&hslot->lock);
 306fail:
 307        return error;
 308}
 309EXPORT_SYMBOL(udp_lib_get_port);
 310
 311static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 312{
 313        struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 314
 315        return  (!ipv6_only_sock(sk2)  &&
 316                 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
 317                   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 318}
 319
 320static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
 321                                       unsigned int port)
 322{
 323        return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 324}
 325
 326int udp_v4_get_port(struct sock *sk, unsigned short snum)
 327{
 328        unsigned int hash2_nulladdr =
 329                udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
 330        unsigned int hash2_partial =
 331                udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
 332
 333        /* precompute partial secondary hash */
 334        udp_sk(sk)->udp_portaddr_hash = hash2_partial;
 335        return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
 336}
 337
 338static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 339                         unsigned short hnum,
 340                         __be16 sport, __be32 daddr, __be16 dport, int dif)
 341{
 342        int score = -1;
 343
 344        if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 345                        !ipv6_only_sock(sk)) {
 346                struct inet_sock *inet = inet_sk(sk);
 347
 348                score = (sk->sk_family == PF_INET ? 2 : 1);
 349                if (inet->inet_rcv_saddr) {
 350                        if (inet->inet_rcv_saddr != daddr)
 351                                return -1;
 352                        score += 4;
 353                }
 354                if (inet->inet_daddr) {
 355                        if (inet->inet_daddr != saddr)
 356                                return -1;
 357                        score += 4;
 358                }
 359                if (inet->inet_dport) {
 360                        if (inet->inet_dport != sport)
 361                                return -1;
 362                        score += 4;
 363                }
 364                if (sk->sk_bound_dev_if) {
 365                        if (sk->sk_bound_dev_if != dif)
 366                                return -1;
 367                        score += 4;
 368                }
 369        }
 370        return score;
 371}
 372
 373/*
 374 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 375 */
 376static inline int compute_score2(struct sock *sk, struct net *net,
 377                                 __be32 saddr, __be16 sport,
 378                                 __be32 daddr, unsigned int hnum, int dif)
 379{
 380        int score = -1;
 381
 382        if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
 383                struct inet_sock *inet = inet_sk(sk);
 384
 385                if (inet->inet_rcv_saddr != daddr)
 386                        return -1;
 387                if (inet->inet_num != hnum)
 388                        return -1;
 389
 390                score = (sk->sk_family == PF_INET ? 2 : 1);
 391                if (inet->inet_daddr) {
 392                        if (inet->inet_daddr != saddr)
 393                                return -1;
 394                        score += 4;
 395                }
 396                if (inet->inet_dport) {
 397                        if (inet->inet_dport != sport)
 398                                return -1;
 399                        score += 4;
 400                }
 401                if (sk->sk_bound_dev_if) {
 402                        if (sk->sk_bound_dev_if != dif)
 403                                return -1;
 404                        score += 4;
 405                }
 406        }
 407        return score;
 408}
 409
 410static unsigned int udp_ehashfn(struct net *net, const __be32 laddr,
 411                                 const __u16 lport, const __be32 faddr,
 412                                 const __be16 fport)
 413{
 414        static u32 udp_ehash_secret __read_mostly;
 415
 416        net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
 417
 418        return __inet_ehashfn(laddr, lport, faddr, fport,
 419                              udp_ehash_secret + net_hash_mix(net));
 420}
 421
 422
 423/* called with read_rcu_lock() */
 424static struct sock *udp4_lib_lookup2(struct net *net,
 425                __be32 saddr, __be16 sport,
 426                __be32 daddr, unsigned int hnum, int dif,
 427                struct udp_hslot *hslot2, unsigned int slot2)
 428{
 429        struct sock *sk, *result;
 430        struct hlist_nulls_node *node;
 431        int score, badness, matches = 0, reuseport = 0;
 432        u32 hash = 0;
 433
 434begin:
 435        result = NULL;
 436        badness = 0;
 437        udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 438                score = compute_score2(sk, net, saddr, sport,
 439                                      daddr, hnum, dif);
 440                if (score > badness) {
 441                        result = sk;
 442                        badness = score;
 443                        reuseport = sk->sk_reuseport;
 444                        if (reuseport) {
 445                                hash = udp_ehashfn(net, daddr, hnum,
 446                                                   saddr, sport);
 447                                matches = 1;
 448                        }
 449                } else if (score == badness && reuseport) {
 450                        matches++;
 451                        if (((u64)hash * matches) >> 32 == 0)
 452                                result = sk;
 453                        hash = next_pseudo_random32(hash);
 454                }
 455        }
 456        /*
 457         * if the nulls value we got at the end of this lookup is
 458         * not the expected one, we must restart lookup.
 459         * We probably met an item that was moved to another chain.
 460         */
 461        if (get_nulls_value(node) != slot2)
 462                goto begin;
 463        if (result) {
 464                if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 465                        result = NULL;
 466                else if (unlikely(compute_score2(result, net, saddr, sport,
 467                                  daddr, hnum, dif) < badness)) {
 468                        sock_put(result);
 469                        goto begin;
 470                }
 471        }
 472        return result;
 473}
 474
 475/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 476 * harder than this. -DaveM
 477 */
 478struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 479                __be16 sport, __be32 daddr, __be16 dport,
 480                int dif, struct udp_table *udptable)
 481{
 482        struct sock *sk, *result;
 483        struct hlist_nulls_node *node;
 484        unsigned short hnum = ntohs(dport);
 485        unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 486        struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 487        int score, badness, matches = 0, reuseport = 0;
 488        u32 hash = 0;
 489
 490        rcu_read_lock();
 491        if (hslot->count > 10) {
 492                hash2 = udp4_portaddr_hash(net, daddr, hnum);
 493                slot2 = hash2 & udptable->mask;
 494                hslot2 = &udptable->hash2[slot2];
 495                if (hslot->count < hslot2->count)
 496                        goto begin;
 497
 498                result = udp4_lib_lookup2(net, saddr, sport,
 499                                          daddr, hnum, dif,
 500                                          hslot2, slot2);
 501                if (!result) {
 502                        hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 503                        slot2 = hash2 & udptable->mask;
 504                        hslot2 = &udptable->hash2[slot2];
 505                        if (hslot->count < hslot2->count)
 506                                goto begin;
 507
 508                        result = udp4_lib_lookup2(net, saddr, sport,
 509                                                  htonl(INADDR_ANY), hnum, dif,
 510                                                  hslot2, slot2);
 511                }
 512                rcu_read_unlock();
 513                return result;
 514        }
 515begin:
 516        result = NULL;
 517        badness = 0;
 518        sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 519                score = compute_score(sk, net, saddr, hnum, sport,
 520                                      daddr, dport, dif);
 521                if (score > badness) {
 522                        result = sk;
 523                        badness = score;
 524                        reuseport = sk->sk_reuseport;
 525                        if (reuseport) {
 526                                hash = udp_ehashfn(net, daddr, hnum,
 527                                                   saddr, sport);
 528                                matches = 1;
 529                        }
 530                } else if (score == badness && reuseport) {
 531                        matches++;
 532                        if (((u64)hash * matches) >> 32 == 0)
 533                                result = sk;
 534                        hash = next_pseudo_random32(hash);
 535                }
 536        }
 537        /*
 538         * if the nulls value we got at the end of this lookup is
 539         * not the expected one, we must restart lookup.
 540         * We probably met an item that was moved to another chain.
 541         */
 542        if (get_nulls_value(node) != slot)
 543                goto begin;
 544
 545        if (result) {
 546                if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 547                        result = NULL;
 548                else if (unlikely(compute_score(result, net, saddr, hnum, sport,
 549                                  daddr, dport, dif) < badness)) {
 550                        sock_put(result);
 551                        goto begin;
 552                }
 553        }
 554        rcu_read_unlock();
 555        return result;
 556}
 557EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
 558
 559static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 560                                                 __be16 sport, __be16 dport,
 561                                                 struct udp_table *udptable)
 562{
 563        const struct iphdr *iph = ip_hdr(skb);
 564
 565        return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
 566                                 iph->daddr, dport, inet_iif(skb),
 567                                 udptable);
 568}
 569
 570struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 571                             __be32 daddr, __be16 dport, int dif)
 572{
 573        return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
 574}
 575EXPORT_SYMBOL_GPL(udp4_lib_lookup);
 576
 577static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
 578                                       __be16 loc_port, __be32 loc_addr,
 579                                       __be16 rmt_port, __be32 rmt_addr,
 580                                       int dif, unsigned short hnum)
 581{
 582        struct inet_sock *inet = inet_sk(sk);
 583
 584        if (!net_eq(sock_net(sk), net) ||
 585            udp_sk(sk)->udp_port_hash != hnum ||
 586            (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
 587            (inet->inet_dport != rmt_port && inet->inet_dport) ||
 588            (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
 589            ipv6_only_sock(sk) ||
 590            (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
 591                return false;
 592        if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif))
 593                return false;
 594        return true;
 595}
 596
 597static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
 598                                             __be16 loc_port, __be32 loc_addr,
 599                                             __be16 rmt_port, __be32 rmt_addr,
 600                                             int dif)
 601{
 602        struct hlist_nulls_node *node;
 603        struct sock *s = sk;
 604        unsigned short hnum = ntohs(loc_port);
 605
 606        sk_nulls_for_each_from(s, node) {
 607                if (__udp_is_mcast_sock(net, s,
 608                                        loc_port, loc_addr,
 609                                        rmt_port, rmt_addr,
 610                                        dif, hnum))
 611                        goto found;
 612        }
 613        s = NULL;
 614found:
 615        return s;
 616}
 617
 618/*
 619 * This routine is called by the ICMP module when it gets some
 620 * sort of error condition.  If err < 0 then the socket should
 621 * be closed and the error returned to the user.  If err > 0
 622 * it's just the icmp type << 8 | icmp code.
 623 * Header points to the ip header of the error packet. We move
 624 * on past this. Then (as it used to claim before adjustment)
 625 * header points to the first 8 bytes of the udp header.  We need
 626 * to find the appropriate port.
 627 */
 628
 629void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 630{
 631        struct inet_sock *inet;
 632        const struct iphdr *iph = (const struct iphdr *)skb->data;
 633        struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
 634        const int type = icmp_hdr(skb)->type;
 635        const int code = icmp_hdr(skb)->code;
 636        struct sock *sk;
 637        int harderr;
 638        int err;
 639        struct net *net = dev_net(skb->dev);
 640
 641        sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
 642                        iph->saddr, uh->source, skb->dev->ifindex, udptable);
 643        if (sk == NULL) {
 644                ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 645                return; /* No socket for error */
 646        }
 647
 648        err = 0;
 649        harderr = 0;
 650        inet = inet_sk(sk);
 651
 652        switch (type) {
 653        default:
 654        case ICMP_TIME_EXCEEDED:
 655                err = EHOSTUNREACH;
 656                break;
 657        case ICMP_SOURCE_QUENCH:
 658                goto out;
 659        case ICMP_PARAMETERPROB:
 660                err = EPROTO;
 661                harderr = 1;
 662                break;
 663        case ICMP_DEST_UNREACH:
 664                if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 665                        ipv4_sk_update_pmtu(skb, sk, info);
 666                        if (inet->pmtudisc != IP_PMTUDISC_DONT) {
 667                                err = EMSGSIZE;
 668                                harderr = 1;
 669                                break;
 670                        }
 671                        goto out;
 672                }
 673                err = EHOSTUNREACH;
 674                if (code <= NR_ICMP_UNREACH) {
 675                        harderr = icmp_err_convert[code].fatal;
 676                        err = icmp_err_convert[code].errno;
 677                }
 678                break;
 679        case ICMP_REDIRECT:
 680                ipv4_sk_redirect(skb, sk);
 681                goto out;
 682        }
 683
 684        /*
 685         *      RFC1122: OK.  Passes ICMP errors back to application, as per
 686         *      4.1.3.3.
 687         */
 688        if (!inet->recverr) {
 689                if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 690                        goto out;
 691        } else
 692                ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
 693
 694        sk->sk_err = err;
 695        sk->sk_error_report(sk);
 696out:
 697        sock_put(sk);
 698}
 699
 700void udp_err(struct sk_buff *skb, u32 info)
 701{
 702        __udp4_lib_err(skb, info, &udp_table);
 703}
 704
 705/*
 706 * Throw away all pending data and cancel the corking. Socket is locked.
 707 */
 708void udp_flush_pending_frames(struct sock *sk)
 709{
 710        struct udp_sock *up = udp_sk(sk);
 711
 712        if (up->pending) {
 713                up->len = 0;
 714                up->pending = 0;
 715                ip_flush_pending_frames(sk);
 716        }
 717}
 718EXPORT_SYMBOL(udp_flush_pending_frames);
 719
 720/**
 721 *      udp4_hwcsum  -  handle outgoing HW checksumming
 722 *      @skb:   sk_buff containing the filled-in UDP header
 723 *              (checksum field must be zeroed out)
 724 *      @src:   source IP address
 725 *      @dst:   destination IP address
 726 */
 727void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
 728{
 729        struct udphdr *uh = udp_hdr(skb);
 730        int offset = skb_transport_offset(skb);
 731        int len = skb->len - offset;
 732        int hlen = len;
 733        __wsum csum = 0;
 734
 735        if (!skb_has_frag_list(skb)) {
 736                /*
 737                 * Only one fragment on the socket.
 738                 */
 739                skb->csum_start = skb_transport_header(skb) - skb->head;
 740                skb->csum_offset = offsetof(struct udphdr, check);
 741                uh->check = ~csum_tcpudp_magic(src, dst, len,
 742                                               IPPROTO_UDP, 0);
 743        } else {
 744                struct sk_buff *frags;
 745
 746                /*
 747                 * HW-checksum won't work as there are two or more
 748                 * fragments on the socket so that all csums of sk_buffs
 749                 * should be together
 750                 */
 751                skb_walk_frags(skb, frags) {
 752                        csum = csum_add(csum, frags->csum);
 753                        hlen -= frags->len;
 754                }
 755
 756                csum = skb_checksum(skb, offset, hlen, csum);
 757                skb->ip_summed = CHECKSUM_NONE;
 758
 759                uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
 760                if (uh->check == 0)
 761                        uh->check = CSUM_MANGLED_0;
 762        }
 763}
 764EXPORT_SYMBOL_GPL(udp4_hwcsum);
 765
 766/* Function to set UDP checksum for an IPv4 UDP packet. This is intended
 767 * for the simple case like when setting the checksum for a UDP tunnel.
 768 */
 769void udp_set_csum(bool nocheck, struct sk_buff *skb,
 770                  __be32 saddr, __be32 daddr, int len)
 771{
 772        struct udphdr *uh = udp_hdr(skb);
 773
 774        if (nocheck)
 775                uh->check = 0;
 776        else if (skb_is_gso(skb))
 777                uh->check = ~udp_v4_check(len, saddr, daddr, 0);
 778        else if (skb_dst(skb) && skb_dst(skb)->dev &&
 779                 (skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
 780
 781                BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
 782
 783                skb->ip_summed = CHECKSUM_PARTIAL;
 784                skb->csum_start = skb_transport_header(skb) - skb->head;
 785                skb->csum_offset = offsetof(struct udphdr, check);
 786                uh->check = ~udp_v4_check(len, saddr, daddr, 0);
 787        } else {
 788                __wsum csum;
 789
 790                BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
 791
 792                uh->check = 0;
 793                csum = skb_checksum(skb, 0, len, 0);
 794                uh->check = udp_v4_check(len, saddr, daddr, csum);
 795                if (uh->check == 0)
 796                        uh->check = CSUM_MANGLED_0;
 797
 798                skb->ip_summed = CHECKSUM_UNNECESSARY;
 799        }
 800}
 801EXPORT_SYMBOL(udp_set_csum);
 802
 803static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 804{
 805        struct sock *sk = skb->sk;
 806        struct inet_sock *inet = inet_sk(sk);
 807        struct udphdr *uh;
 808        int err = 0;
 809        int is_udplite = IS_UDPLITE(sk);
 810        int offset = skb_transport_offset(skb);
 811        int len = skb->len - offset;
 812        __wsum csum = 0;
 813
 814        /*
 815         * Create a UDP header
 816         */
 817        uh = udp_hdr(skb);
 818        uh->source = inet->inet_sport;
 819        uh->dest = fl4->fl4_dport;
 820        uh->len = htons(len);
 821        uh->check = 0;
 822
 823        if (is_udplite)                                  /*     UDP-Lite      */
 824                csum = udplite_csum(skb);
 825
 826        else if (sk->sk_no_check_tx) {   /* UDP csum disabled */
 827
 828                skb->ip_summed = CHECKSUM_NONE;
 829                goto send;
 830
 831        } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 832
 833                udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
 834                goto send;
 835
 836        } else
 837                csum = udp_csum(skb);
 838
 839        /* add protocol-dependent pseudo-header */
 840        uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
 841                                      sk->sk_protocol, csum);
 842        if (uh->check == 0)
 843                uh->check = CSUM_MANGLED_0;
 844
 845send:
 846        err = ip_send_skb(sock_net(sk), skb);
 847        if (err) {
 848                if (err == -ENOBUFS && !inet->recverr) {
 849                        UDP_INC_STATS_USER(sock_net(sk),
 850                                           UDP_MIB_SNDBUFERRORS, is_udplite);
 851                        err = 0;
 852                }
 853        } else
 854                UDP_INC_STATS_USER(sock_net(sk),
 855                                   UDP_MIB_OUTDATAGRAMS, is_udplite);
 856        return err;
 857}
 858
 859/*
 860 * Push out all pending data as one UDP datagram. Socket is locked.
 861 */
 862int udp_push_pending_frames(struct sock *sk)
 863{
 864        struct udp_sock  *up = udp_sk(sk);
 865        struct inet_sock *inet = inet_sk(sk);
 866        struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
 867        struct sk_buff *skb;
 868        int err = 0;
 869
 870        skb = ip_finish_skb(sk, fl4);
 871        if (!skb)
 872                goto out;
 873
 874        err = udp_send_skb(skb, fl4);
 875
 876out:
 877        up->len = 0;
 878        up->pending = 0;
 879        return err;
 880}
 881EXPORT_SYMBOL(udp_push_pending_frames);
 882
 883int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 884                size_t len)
 885{
 886        struct inet_sock *inet = inet_sk(sk);
 887        struct udp_sock *up = udp_sk(sk);
 888        struct flowi4 fl4_stack;
 889        struct flowi4 *fl4;
 890        int ulen = len;
 891        struct ipcm_cookie ipc;
 892        struct rtable *rt = NULL;
 893        int free = 0;
 894        int connected = 0;
 895        __be32 daddr, faddr, saddr;
 896        __be16 dport;
 897        u8  tos;
 898        int err, is_udplite = IS_UDPLITE(sk);
 899        int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 900        int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 901        struct sk_buff *skb;
 902        struct ip_options_data opt_copy;
 903
 904        if (len > 0xFFFF)
 905                return -EMSGSIZE;
 906
 907        /*
 908         *      Check the flags.
 909         */
 910
 911        if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
 912                return -EOPNOTSUPP;
 913
 914        ipc.opt = NULL;
 915        ipc.tx_flags = 0;
 916        ipc.ttl = 0;
 917        ipc.tos = -1;
 918
 919        getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 920
 921        fl4 = &inet->cork.fl.u.ip4;
 922        if (up->pending) {
 923                /*
 924                 * There are pending frames.
 925                 * The socket lock must be held while it's corked.
 926                 */
 927                lock_sock(sk);
 928                if (likely(up->pending)) {
 929                        if (unlikely(up->pending != AF_INET)) {
 930                                release_sock(sk);
 931                                return -EINVAL;
 932                        }
 933                        goto do_append_data;
 934                }
 935                release_sock(sk);
 936        }
 937        ulen += sizeof(struct udphdr);
 938
 939        /*
 940         *      Get and verify the address.
 941         */
 942        if (msg->msg_name) {
 943                DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 944                if (msg->msg_namelen < sizeof(*usin))
 945                        return -EINVAL;
 946                if (usin->sin_family != AF_INET) {
 947                        if (usin->sin_family != AF_UNSPEC)
 948                                return -EAFNOSUPPORT;
 949                }
 950
 951                daddr = usin->sin_addr.s_addr;
 952                dport = usin->sin_port;
 953                if (dport == 0)
 954                        return -EINVAL;
 955        } else {
 956                if (sk->sk_state != TCP_ESTABLISHED)
 957                        return -EDESTADDRREQ;
 958                daddr = inet->inet_daddr;
 959                dport = inet->inet_dport;
 960                /* Open fast path for connected socket.
 961                   Route will not be used, if at least one option is set.
 962                 */
 963                connected = 1;
 964        }
 965        ipc.addr = inet->inet_saddr;
 966
 967        ipc.oif = sk->sk_bound_dev_if;
 968
 969        sock_tx_timestamp(sk, &ipc.tx_flags);
 970
 971        if (msg->msg_controllen) {
 972                err = ip_cmsg_send(sock_net(sk), msg, &ipc,
 973                                   sk->sk_family == AF_INET6);
 974                if (err)
 975                        return err;
 976                if (ipc.opt)
 977                        free = 1;
 978                connected = 0;
 979        }
 980        if (!ipc.opt) {
 981                struct ip_options_rcu *inet_opt;
 982
 983                rcu_read_lock();
 984                inet_opt = rcu_dereference(inet->inet_opt);
 985                if (inet_opt) {
 986                        memcpy(&opt_copy, inet_opt,
 987                               sizeof(*inet_opt) + inet_opt->opt.optlen);
 988                        ipc.opt = &opt_copy.opt;
 989                }
 990                rcu_read_unlock();
 991        }
 992
 993        saddr = ipc.addr;
 994        ipc.addr = faddr = daddr;
 995
 996        if (ipc.opt && ipc.opt->opt.srr) {
 997                if (!daddr)
 998                        return -EINVAL;
 999                faddr = ipc.opt->opt.faddr;
1000                connected = 0;
1001        }
1002        tos = get_rttos(&ipc, inet);
1003        if (sock_flag(sk, SOCK_LOCALROUTE) ||
1004            (msg->msg_flags & MSG_DONTROUTE) ||
1005            (ipc.opt && ipc.opt->opt.is_strictroute)) {
1006                tos |= RTO_ONLINK;
1007                connected = 0;
1008        }
1009
1010        if (ipv4_is_multicast(daddr)) {
1011                if (!ipc.oif)
1012                        ipc.oif = inet->mc_index;
1013                if (!saddr)
1014                        saddr = inet->mc_addr;
1015                connected = 0;
1016        } else if (!ipc.oif)
1017                ipc.oif = inet->uc_index;
1018
1019        if (connected)
1020                rt = (struct rtable *)sk_dst_check(sk, 0);
1021
1022        if (rt == NULL) {
1023                struct net *net = sock_net(sk);
1024
1025                fl4 = &fl4_stack;
1026                flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
1027                                   RT_SCOPE_UNIVERSE, sk->sk_protocol,
1028                                   inet_sk_flowi_flags(sk),
1029                                   faddr, saddr, dport, inet->inet_sport);
1030
1031                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
1032                rt = ip_route_output_flow(net, fl4, sk);
1033                if (IS_ERR(rt)) {
1034                        err = PTR_ERR(rt);
1035                        rt = NULL;
1036                        if (err == -ENETUNREACH)
1037                                IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1038                        goto out;
1039                }
1040
1041                err = -EACCES;
1042                if ((rt->rt_flags & RTCF_BROADCAST) &&
1043                    !sock_flag(sk, SOCK_BROADCAST))
1044                        goto out;
1045                if (connected)
1046                        sk_dst_set(sk, dst_clone(&rt->dst));
1047        }
1048
1049        if (msg->msg_flags&MSG_CONFIRM)
1050                goto do_confirm;
1051back_from_confirm:
1052
1053        saddr = fl4->saddr;
1054        if (!ipc.addr)
1055                daddr = ipc.addr = fl4->daddr;
1056
1057        /* Lockless fast path for the non-corking case. */
1058        if (!corkreq) {
1059                skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
1060                                  sizeof(struct udphdr), &ipc, &rt,
1061                                  msg->msg_flags);
1062                err = PTR_ERR(skb);
1063                if (!IS_ERR_OR_NULL(skb))
1064                        err = udp_send_skb(skb, fl4);
1065                goto out;
1066        }
1067
1068        lock_sock(sk);
1069        if (unlikely(up->pending)) {
1070                /* The socket is already corked while preparing it. */
1071                /* ... which is an evident application bug. --ANK */
1072                release_sock(sk);
1073
1074                LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
1075                err = -EINVAL;
1076                goto out;
1077        }
1078        /*
1079         *      Now cork the socket to pend data.
1080         */
1081        fl4 = &inet->cork.fl.u.ip4;
1082        fl4->daddr = daddr;
1083        fl4->saddr = saddr;
1084        fl4->fl4_dport = dport;
1085        fl4->fl4_sport = inet->inet_sport;
1086        up->pending = AF_INET;
1087
1088do_append_data:
1089        up->len += ulen;
1090        err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
1091                             sizeof(struct udphdr), &ipc, &rt,
1092                             corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1093        if (err)
1094                udp_flush_pending_frames(sk);
1095        else if (!corkreq)
1096                err = udp_push_pending_frames(sk);
1097        else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1098                up->pending = 0;
1099        release_sock(sk);
1100
1101out:
1102        ip_rt_put(rt);
1103        if (free)
1104                kfree(ipc.opt);
1105        if (!err)
1106                return len;
1107        /*
1108         * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1109         * ENOBUFS might not be good (it's not tunable per se), but otherwise
1110         * we don't have a good statistic (IpOutDiscards but it can be too many
1111         * things).  We could add another new stat but at least for now that
1112         * seems like overkill.
1113         */
1114        if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1115                UDP_INC_STATS_USER(sock_net(sk),
1116                                UDP_MIB_SNDBUFERRORS, is_udplite);
1117        }
1118        return err;
1119
1120do_confirm:
1121        dst_confirm(&rt->dst);
1122        if (!(msg->msg_flags&MSG_PROBE) || len)
1123                goto back_from_confirm;
1124        err = 0;
1125        goto out;
1126}
1127EXPORT_SYMBOL(udp_sendmsg);
1128
1129int udp_sendpage(struct sock *sk, struct page *page, int offset,
1130                 size_t size, int flags)
1131{
1132        struct inet_sock *inet = inet_sk(sk);
1133        struct udp_sock *up = udp_sk(sk);
1134        int ret;
1135
1136        if (flags & MSG_SENDPAGE_NOTLAST)
1137                flags |= MSG_MORE;
1138
1139        if (!up->pending) {
1140                struct msghdr msg = {   .msg_flags = flags|MSG_MORE };
1141
1142                /* Call udp_sendmsg to specify destination address which
1143                 * sendpage interface can't pass.
1144                 * This will succeed only when the socket is connected.
1145                 */
1146                ret = udp_sendmsg(NULL, sk, &msg, 0);
1147                if (ret < 0)
1148                        return ret;
1149        }
1150
1151        lock_sock(sk);
1152
1153        if (unlikely(!up->pending)) {
1154                release_sock(sk);
1155
1156                LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1157                return -EINVAL;
1158        }
1159
1160        ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1161                             page, offset, size, flags);
1162        if (ret == -EOPNOTSUPP) {
1163                release_sock(sk);
1164                return sock_no_sendpage(sk->sk_socket, page, offset,
1165                                        size, flags);
1166        }
1167        if (ret < 0) {
1168                udp_flush_pending_frames(sk);
1169                goto out;
1170        }
1171
1172        up->len += size;
1173        if (!(up->corkflag || (flags&MSG_MORE)))
1174                ret = udp_push_pending_frames(sk);
1175        if (!ret)
1176                ret = size;
1177out:
1178        release_sock(sk);
1179        return ret;
1180}
1181
1182
1183/**
1184 *      first_packet_length     - return length of first packet in receive queue
1185 *      @sk: socket
1186 *
1187 *      Drops all bad checksum frames, until a valid one is found.
1188 *      Returns the length of found skb, or 0 if none is found.
1189 */
1190static unsigned int first_packet_length(struct sock *sk)
1191{
1192        struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
1193        struct sk_buff *skb;
1194        unsigned int res;
1195
1196        __skb_queue_head_init(&list_kill);
1197
1198        spin_lock_bh(&rcvq->lock);
1199        while ((skb = skb_peek(rcvq)) != NULL &&
1200                udp_lib_checksum_complete(skb)) {
1201                UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS,
1202                                 IS_UDPLITE(sk));
1203                UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1204                                 IS_UDPLITE(sk));
1205                atomic_inc(&sk->sk_drops);
1206                __skb_unlink(skb, rcvq);
1207                __skb_queue_tail(&list_kill, skb);
1208        }
1209        res = skb ? skb->len : 0;
1210        spin_unlock_bh(&rcvq->lock);
1211
1212        if (!skb_queue_empty(&list_kill)) {
1213                bool slow = lock_sock_fast(sk);
1214
1215                __skb_queue_purge(&list_kill);
1216                sk_mem_reclaim_partial(sk);
1217                unlock_sock_fast(sk, slow);
1218        }
1219        return res;
1220}
1221
1222/*
1223 *      IOCTL requests applicable to the UDP protocol
1224 */
1225
1226int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1227{
1228        switch (cmd) {
1229        case SIOCOUTQ:
1230        {
1231                int amount = sk_wmem_alloc_get(sk);
1232
1233                return put_user(amount, (int __user *)arg);
1234        }
1235
1236        case SIOCINQ:
1237        {
1238                unsigned int amount = first_packet_length(sk);
1239
1240                if (amount)
1241                        /*
1242                         * We will only return the amount
1243                         * of this packet since that is all
1244                         * that will be read.
1245                         */
1246                        amount -= sizeof(struct udphdr);
1247
1248                return put_user(amount, (int __user *)arg);
1249        }
1250
1251        default:
1252                return -ENOIOCTLCMD;
1253        }
1254
1255        return 0;
1256}
1257EXPORT_SYMBOL(udp_ioctl);
1258
1259/*
1260 *      This should be easy, if there is something there we
1261 *      return it, otherwise we block.
1262 */
1263
1264int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1265                size_t len, int noblock, int flags, int *addr_len)
1266{
1267        struct inet_sock *inet = inet_sk(sk);
1268        DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1269        struct sk_buff *skb;
1270        unsigned int ulen, copied;
1271        int peeked, off = 0;
1272        int err;
1273        int is_udplite = IS_UDPLITE(sk);
1274        bool slow;
1275
1276        if (flags & MSG_ERRQUEUE)
1277                return ip_recv_error(sk, msg, len, addr_len);
1278
1279try_again:
1280        skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1281                                  &peeked, &off, &err);
1282        if (!skb)
1283                goto out;
1284
1285        ulen = skb->len - sizeof(struct udphdr);
1286        copied = len;
1287        if (copied > ulen)
1288                copied = ulen;
1289        else if (copied < ulen)
1290                msg->msg_flags |= MSG_TRUNC;
1291
1292        /*
1293         * If checksum is needed at all, try to do it while copying the
1294         * data.  If the data is truncated, or if we only want a partial
1295         * coverage checksum (UDP-Lite), do it before the copy.
1296         */
1297
1298        if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1299                if (udp_lib_checksum_complete(skb))
1300                        goto csum_copy_err;
1301        }
1302
1303        if (skb_csum_unnecessary(skb))
1304                err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1305                                              msg->msg_iov, copied);
1306        else {
1307                err = skb_copy_and_csum_datagram_iovec(skb,
1308                                                       sizeof(struct udphdr),
1309                                                       msg->msg_iov);
1310
1311                if (err == -EINVAL)
1312                        goto csum_copy_err;
1313        }
1314
1315        if (unlikely(err)) {
1316                trace_kfree_skb(skb, udp_recvmsg);
1317                if (!peeked) {
1318                        atomic_inc(&sk->sk_drops);
1319                        UDP_INC_STATS_USER(sock_net(sk),
1320                                           UDP_MIB_INERRORS, is_udplite);
1321                }
1322                goto out_free;
1323        }
1324
1325        if (!peeked)
1326                UDP_INC_STATS_USER(sock_net(sk),
1327                                UDP_MIB_INDATAGRAMS, is_udplite);
1328
1329        sock_recv_ts_and_drops(msg, sk, skb);
1330
1331        /* Copy the address. */
1332        if (sin) {
1333                sin->sin_family = AF_INET;
1334                sin->sin_port = udp_hdr(skb)->source;
1335                sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1336                memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1337                *addr_len = sizeof(*sin);
1338        }
1339        if (inet->cmsg_flags)
1340                ip_cmsg_recv(msg, skb);
1341
1342        err = copied;
1343        if (flags & MSG_TRUNC)
1344                err = ulen;
1345
1346out_free:
1347        skb_free_datagram_locked(sk, skb);
1348out:
1349        return err;
1350
1351csum_copy_err:
1352        slow = lock_sock_fast(sk);
1353        if (!skb_kill_datagram(sk, skb, flags)) {
1354                UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1355                UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1356        }
1357        unlock_sock_fast(sk, slow);
1358
1359        if (noblock)
1360                return -EAGAIN;
1361
1362        /* starting over for a new packet */
1363        msg->msg_flags &= ~MSG_TRUNC;
1364        goto try_again;
1365}
1366
1367
1368int udp_disconnect(struct sock *sk, int flags)
1369{
1370        struct inet_sock *inet = inet_sk(sk);
1371        /*
1372         *      1003.1g - break association.
1373         */
1374
1375        sk->sk_state = TCP_CLOSE;
1376        inet->inet_daddr = 0;
1377        inet->inet_dport = 0;
1378        sock_rps_reset_rxhash(sk);
1379        sk->sk_bound_dev_if = 0;
1380        if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1381                inet_reset_saddr(sk);
1382
1383        if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1384                sk->sk_prot->unhash(sk);
1385                inet->inet_sport = 0;
1386        }
1387        sk_dst_reset(sk);
1388        return 0;
1389}
1390EXPORT_SYMBOL(udp_disconnect);
1391
1392void udp_lib_unhash(struct sock *sk)
1393{
1394        if (sk_hashed(sk)) {
1395                struct udp_table *udptable = sk->sk_prot->h.udp_table;
1396                struct udp_hslot *hslot, *hslot2;
1397
1398                hslot  = udp_hashslot(udptable, sock_net(sk),
1399                                      udp_sk(sk)->udp_port_hash);
1400                hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1401
1402                spin_lock_bh(&hslot->lock);
1403                if (sk_nulls_del_node_init_rcu(sk)) {
1404                        hslot->count--;
1405                        inet_sk(sk)->inet_num = 0;
1406                        sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1407
1408                        spin_lock(&hslot2->lock);
1409                        hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1410                        hslot2->count--;
1411                        spin_unlock(&hslot2->lock);
1412                }
1413                spin_unlock_bh(&hslot->lock);
1414        }
1415}
1416EXPORT_SYMBOL(udp_lib_unhash);
1417
1418/*
1419 * inet_rcv_saddr was changed, we must rehash secondary hash
1420 */
1421void udp_lib_rehash(struct sock *sk, u16 newhash)
1422{
1423        if (sk_hashed(sk)) {
1424                struct udp_table *udptable = sk->sk_prot->h.udp_table;
1425                struct udp_hslot *hslot, *hslot2, *nhslot2;
1426
1427                hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1428                nhslot2 = udp_hashslot2(udptable, newhash);
1429                udp_sk(sk)->udp_portaddr_hash = newhash;
1430                if (hslot2 != nhslot2) {
1431                        hslot = udp_hashslot(udptable, sock_net(sk),
1432                                             udp_sk(sk)->udp_port_hash);
1433                        /* we must lock primary chain too */
1434                        spin_lock_bh(&hslot->lock);
1435
1436                        spin_lock(&hslot2->lock);
1437                        hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1438                        hslot2->count--;
1439                        spin_unlock(&hslot2->lock);
1440
1441                        spin_lock(&nhslot2->lock);
1442                        hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1443                                                 &nhslot2->head);
1444                        nhslot2->count++;
1445                        spin_unlock(&nhslot2->lock);
1446
1447                        spin_unlock_bh(&hslot->lock);
1448                }
1449        }
1450}
1451EXPORT_SYMBOL(udp_lib_rehash);
1452
1453static void udp_v4_rehash(struct sock *sk)
1454{
1455        u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1456                                          inet_sk(sk)->inet_rcv_saddr,
1457                                          inet_sk(sk)->inet_num);
1458        udp_lib_rehash(sk, new_hash);
1459}
1460
1461static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1462{
1463        int rc;
1464
1465        if (inet_sk(sk)->inet_daddr) {
1466                sock_rps_save_rxhash(sk, skb);
1467                sk_mark_napi_id(sk, skb);
1468        }
1469
1470        rc = sock_queue_rcv_skb(sk, skb);
1471        if (rc < 0) {
1472                int is_udplite = IS_UDPLITE(sk);
1473
1474                /* Note that an ENOMEM error is charged twice */
1475                if (rc == -ENOMEM)
1476                        UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1477                                         is_udplite);
1478                UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1479                kfree_skb(skb);
1480                trace_udp_fail_queue_rcv_skb(rc, sk);
1481                return -1;
1482        }
1483
1484        return 0;
1485
1486}
1487
1488static struct static_key udp_encap_needed __read_mostly;
1489void udp_encap_enable(void)
1490{
1491        if (!static_key_enabled(&udp_encap_needed))
1492                static_key_slow_inc(&udp_encap_needed);
1493}
1494EXPORT_SYMBOL(udp_encap_enable);
1495
1496/* returns:
1497 *  -1: error
1498 *   0: success
1499 *  >0: "udp encap" protocol resubmission
1500 *
1501 * Note that in the success and error cases, the skb is assumed to
1502 * have either been requeued or freed.
1503 */
1504int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1505{
1506        struct udp_sock *up = udp_sk(sk);
1507        int rc;
1508        int is_udplite = IS_UDPLITE(sk);
1509
1510        /*
1511         *      Charge it to the socket, dropping if the queue is full.
1512         */
1513        if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1514                goto drop;
1515        nf_reset(skb);
1516
1517        if (static_key_false(&udp_encap_needed) && up->encap_type) {
1518                int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1519
1520                /*
1521                 * This is an encapsulation socket so pass the skb to
1522                 * the socket's udp_encap_rcv() hook. Otherwise, just
1523                 * fall through and pass this up the UDP socket.
1524                 * up->encap_rcv() returns the following value:
1525                 * =0 if skb was successfully passed to the encap
1526                 *    handler or was discarded by it.
1527                 * >0 if skb should be passed on to UDP.
1528                 * <0 if skb should be resubmitted as proto -N
1529                 */
1530
1531                /* if we're overly short, let UDP handle it */
1532                encap_rcv = ACCESS_ONCE(up->encap_rcv);
1533                if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1534                        int ret;
1535
1536                        /* Verify checksum before giving to encap */
1537                        if (udp_lib_checksum_complete(skb))
1538                                goto csum_error;
1539
1540                        ret = encap_rcv(sk, skb);
1541                        if (ret <= 0) {
1542                                UDP_INC_STATS_BH(sock_net(sk),
1543                                                 UDP_MIB_INDATAGRAMS,
1544                                                 is_udplite);
1545                                return -ret;
1546                        }
1547                }
1548
1549                /* FALLTHROUGH -- it's a UDP Packet */
1550        }
1551
1552        /*
1553         *      UDP-Lite specific tests, ignored on UDP sockets
1554         */
1555        if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1556
1557                /*
1558                 * MIB statistics other than incrementing the error count are
1559                 * disabled for the following two types of errors: these depend
1560                 * on the application settings, not on the functioning of the
1561                 * protocol stack as such.
1562                 *
1563                 * RFC 3828 here recommends (sec 3.3): "There should also be a
1564                 * way ... to ... at least let the receiving application block
1565                 * delivery of packets with coverage values less than a value
1566                 * provided by the application."
1567                 */
1568                if (up->pcrlen == 0) {          /* full coverage was set  */
1569                        LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
1570                                       UDP_SKB_CB(skb)->cscov, skb->len);
1571                        goto drop;
1572                }
1573                /* The next case involves violating the min. coverage requested
1574                 * by the receiver. This is subtle: if receiver wants x and x is
1575                 * greater than the buffersize/MTU then receiver will complain
1576                 * that it wants x while sender emits packets of smaller size y.
1577                 * Therefore the above ...()->partial_cov statement is essential.
1578                 */
1579                if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1580                        LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
1581                                       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1582                        goto drop;
1583                }
1584        }
1585
1586        if (rcu_access_pointer(sk->sk_filter) &&
1587            udp_lib_checksum_complete(skb))
1588                goto csum_error;
1589
1590
1591        if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf)) {
1592                UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1593                                 is_udplite);
1594                goto drop;
1595        }
1596
1597        rc = 0;
1598
1599        ipv4_pktinfo_prepare(sk, skb);
1600        bh_lock_sock(sk);
1601        if (!sock_owned_by_user(sk))
1602                rc = __udp_queue_rcv_skb(sk, skb);
1603        else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
1604                bh_unlock_sock(sk);
1605                goto drop;
1606        }
1607        bh_unlock_sock(sk);
1608
1609        return rc;
1610
1611csum_error:
1612        UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1613drop:
1614        UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1615        atomic_inc(&sk->sk_drops);
1616        kfree_skb(skb);
1617        return -1;
1618}
1619
1620
1621static void flush_stack(struct sock **stack, unsigned int count,
1622                        struct sk_buff *skb, unsigned int final)
1623{
1624        unsigned int i;
1625        struct sk_buff *skb1 = NULL;
1626        struct sock *sk;
1627
1628        for (i = 0; i < count; i++) {
1629                sk = stack[i];
1630                if (likely(skb1 == NULL))
1631                        skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1632
1633                if (!skb1) {
1634                        atomic_inc(&sk->sk_drops);
1635                        UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1636                                         IS_UDPLITE(sk));
1637                        UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1638                                         IS_UDPLITE(sk));
1639                }
1640
1641                if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1642                        skb1 = NULL;
1643        }
1644        if (unlikely(skb1))
1645                kfree_skb(skb1);
1646}
1647
1648/* For TCP sockets, sk_rx_dst is protected by socket lock
1649 * For UDP, we use xchg() to guard against concurrent changes.
1650 */
1651static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
1652{
1653        struct dst_entry *old;
1654
1655        dst_hold(dst);
1656        old = xchg(&sk->sk_rx_dst, dst);
1657        dst_release(old);
1658}
1659
1660/*
1661 *      Multicasts and broadcasts go to each listener.
1662 *
1663 *      Note: called only from the BH handler context.
1664 */
1665static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1666                                    struct udphdr  *uh,
1667                                    __be32 saddr, __be32 daddr,
1668                                    struct udp_table *udptable)
1669{
1670        struct sock *sk, *stack[256 / sizeof(struct sock *)];
1671        struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1672        int dif;
1673        unsigned int i, count = 0;
1674
1675        spin_lock(&hslot->lock);
1676        sk = sk_nulls_head(&hslot->head);
1677        dif = skb->dev->ifindex;
1678        sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1679        while (sk) {
1680                stack[count++] = sk;
1681                sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1682                                       daddr, uh->source, saddr, dif);
1683                if (unlikely(count == ARRAY_SIZE(stack))) {
1684                        if (!sk)
1685                                break;
1686                        flush_stack(stack, count, skb, ~0);
1687                        count = 0;
1688                }
1689        }
1690        /*
1691         * before releasing chain lock, we must take a reference on sockets
1692         */
1693        for (i = 0; i < count; i++)
1694                sock_hold(stack[i]);
1695
1696        spin_unlock(&hslot->lock);
1697
1698        /*
1699         * do the slow work with no lock held
1700         */
1701        if (count) {
1702                flush_stack(stack, count, skb, count - 1);
1703
1704                for (i = 0; i < count; i++)
1705                        sock_put(stack[i]);
1706        } else {
1707                kfree_skb(skb);
1708        }
1709        return 0;
1710}
1711
1712/* Initialize UDP checksum. If exited with zero value (success),
1713 * CHECKSUM_UNNECESSARY means, that no more checks are required.
1714 * Otherwise, csum completion requires chacksumming packet body,
1715 * including udp header and folding it to skb->csum.
1716 */
1717static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1718                                 int proto)
1719{
1720        int err;
1721
1722        UDP_SKB_CB(skb)->partial_cov = 0;
1723        UDP_SKB_CB(skb)->cscov = skb->len;
1724
1725        if (proto == IPPROTO_UDPLITE) {
1726                err = udplite_checksum_init(skb, uh);
1727                if (err)
1728                        return err;
1729        }
1730
1731        return skb_checksum_init_zero_check(skb, proto, uh->check,
1732                                            inet_compute_pseudo);
1733}
1734
1735/*
1736 *      All we need to do is get the socket, and then do a checksum.
1737 */
1738
1739int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1740                   int proto)
1741{
1742        struct sock *sk;
1743        struct udphdr *uh;
1744        unsigned short ulen;
1745        struct rtable *rt = skb_rtable(skb);
1746        __be32 saddr, daddr;
1747        struct net *net = dev_net(skb->dev);
1748
1749        /*
1750         *  Validate the packet.
1751         */
1752        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1753                goto drop;              /* No space for header. */
1754
1755        uh   = udp_hdr(skb);
1756        ulen = ntohs(uh->len);
1757        saddr = ip_hdr(skb)->saddr;
1758        daddr = ip_hdr(skb)->daddr;
1759
1760        if (ulen > skb->len)
1761                goto short_packet;
1762
1763        if (proto == IPPROTO_UDP) {
1764                /* UDP validates ulen. */
1765                if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1766                        goto short_packet;
1767                uh = udp_hdr(skb);
1768        }
1769
1770        if (udp4_csum_init(skb, uh, proto))
1771                goto csum_error;
1772
1773        sk = skb_steal_sock(skb);
1774        if (sk) {
1775                struct dst_entry *dst = skb_dst(skb);
1776                int ret;
1777
1778                if (unlikely(sk->sk_rx_dst != dst))
1779                        udp_sk_rx_dst_set(sk, dst);
1780
1781                ret = udp_queue_rcv_skb(sk, skb);
1782                sock_put(sk);
1783                /* a return value > 0 means to resubmit the input, but
1784                 * it wants the return to be -protocol, or 0
1785                 */
1786                if (ret > 0)
1787                        return -ret;
1788                return 0;
1789        } else {
1790                if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1791                        return __udp4_lib_mcast_deliver(net, skb, uh,
1792                                        saddr, daddr, udptable);
1793
1794                sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1795        }
1796
1797        if (sk != NULL) {
1798                int ret;
1799
1800                ret = udp_queue_rcv_skb(sk, skb);
1801                sock_put(sk);
1802
1803                /* a return value > 0 means to resubmit the input, but
1804                 * it wants the return to be -protocol, or 0
1805                 */
1806                if (ret > 0)
1807                        return -ret;
1808                return 0;
1809        }
1810
1811        if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1812                goto drop;
1813        nf_reset(skb);
1814
1815        /* No socket. Drop packet silently, if checksum is wrong */
1816        if (udp_lib_checksum_complete(skb))
1817                goto csum_error;
1818
1819        UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1820        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1821
1822        /*
1823         * Hmm.  We got an UDP packet to a port to which we
1824         * don't wanna listen.  Ignore it.
1825         */
1826        kfree_skb(skb);
1827        return 0;
1828
1829short_packet:
1830        LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1831                       proto == IPPROTO_UDPLITE ? "Lite" : "",
1832                       &saddr, ntohs(uh->source),
1833                       ulen, skb->len,
1834                       &daddr, ntohs(uh->dest));
1835        goto drop;
1836
1837csum_error:
1838        /*
1839         * RFC1122: OK.  Discards the bad packet silently (as far as
1840         * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1841         */
1842        LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1843                       proto == IPPROTO_UDPLITE ? "Lite" : "",
1844                       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1845                       ulen);
1846        UDP_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
1847drop:
1848        UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1849        kfree_skb(skb);
1850        return 0;
1851}
1852
1853/* We can only early demux multicast if there is a single matching socket.
1854 * If more than one socket found returns NULL
1855 */
1856static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
1857                                                  __be16 loc_port, __be32 loc_addr,
1858                                                  __be16 rmt_port, __be32 rmt_addr,
1859                                                  int dif)
1860{
1861        struct sock *sk, *result;
1862        struct hlist_nulls_node *node;
1863        unsigned short hnum = ntohs(loc_port);
1864        unsigned int count, slot = udp_hashfn(net, hnum, udp_table.mask);
1865        struct udp_hslot *hslot = &udp_table.hash[slot];
1866
1867        /* Do not bother scanning a too big list */
1868        if (hslot->count > 10)
1869                return NULL;
1870
1871        rcu_read_lock();
1872begin:
1873        count = 0;
1874        result = NULL;
1875        sk_nulls_for_each_rcu(sk, node, &hslot->head) {
1876                if (__udp_is_mcast_sock(net, sk,
1877                                        loc_port, loc_addr,
1878                                        rmt_port, rmt_addr,
1879                                        dif, hnum)) {
1880                        result = sk;
1881                        ++count;
1882                }
1883        }
1884        /*
1885         * if the nulls value we got at the end of this lookup is
1886         * not the expected one, we must restart lookup.
1887         * We probably met an item that was moved to another chain.
1888         */
1889        if (get_nulls_value(node) != slot)
1890                goto begin;
1891
1892        if (result) {
1893                if (count != 1 ||
1894                    unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1895                        result = NULL;
1896                else if (unlikely(!__udp_is_mcast_sock(net, result,
1897                                                       loc_port, loc_addr,
1898                                                       rmt_port, rmt_addr,
1899                                                       dif, hnum))) {
1900                        sock_put(result);
1901                        result = NULL;
1902                }
1903        }
1904        rcu_read_unlock();
1905        return result;
1906}
1907
1908/* For unicast we should only early demux connected sockets or we can
1909 * break forwarding setups.  The chains here can be long so only check
1910 * if the first socket is an exact match and if not move on.
1911 */
1912static struct sock *__udp4_lib_demux_lookup(struct net *net,
1913                                            __be16 loc_port, __be32 loc_addr,
1914                                            __be16 rmt_port, __be32 rmt_addr,
1915                                            int dif)
1916{
1917        struct sock *sk, *result;
1918        struct hlist_nulls_node *node;
1919        unsigned short hnum = ntohs(loc_port);
1920        unsigned int hash2 = udp4_portaddr_hash(net, loc_addr, hnum);
1921        unsigned int slot2 = hash2 & udp_table.mask;
1922        struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
1923        INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
1924        const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
1925
1926        rcu_read_lock();
1927        result = NULL;
1928        udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
1929                if (INET_MATCH(sk, net, acookie,
1930                               rmt_addr, loc_addr, ports, dif))
1931                        result = sk;
1932                /* Only check first socket in chain */
1933                break;
1934        }
1935
1936        if (result) {
1937                if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1938                        result = NULL;
1939                else if (unlikely(!INET_MATCH(sk, net, acookie,
1940                                              rmt_addr, loc_addr,
1941                                              ports, dif))) {
1942                        sock_put(result);
1943                        result = NULL;
1944                }
1945        }
1946        rcu_read_unlock();
1947        return result;
1948}
1949
1950void udp_v4_early_demux(struct sk_buff *skb)
1951{
1952        struct net *net = dev_net(skb->dev);
1953        const struct iphdr *iph;
1954        const struct udphdr *uh;
1955        struct sock *sk;
1956        struct dst_entry *dst;
1957        int dif = skb->dev->ifindex;
1958
1959        /* validate the packet */
1960        if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
1961                return;
1962
1963        iph = ip_hdr(skb);
1964        uh = udp_hdr(skb);
1965
1966        if (skb->pkt_type == PACKET_BROADCAST ||
1967            skb->pkt_type == PACKET_MULTICAST)
1968                sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
1969                                                   uh->source, iph->saddr, dif);
1970        else if (skb->pkt_type == PACKET_HOST)
1971                sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
1972                                             uh->source, iph->saddr, dif);
1973        else
1974                return;
1975
1976        if (!sk)
1977                return;
1978
1979        skb->sk = sk;
1980        skb->destructor = sock_edemux;
1981        dst = sk->sk_rx_dst;
1982
1983        if (dst)
1984                dst = dst_check(dst, 0);
1985        if (dst)
1986                skb_dst_set_noref(skb, dst);
1987}
1988
1989int udp_rcv(struct sk_buff *skb)
1990{
1991        return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1992}
1993
1994void udp_destroy_sock(struct sock *sk)
1995{
1996        struct udp_sock *up = udp_sk(sk);
1997        bool slow = lock_sock_fast(sk);
1998        udp_flush_pending_frames(sk);
1999        unlock_sock_fast(sk, slow);
2000        if (static_key_false(&udp_encap_needed) && up->encap_type) {
2001                void (*encap_destroy)(struct sock *sk);
2002                encap_destroy = ACCESS_ONCE(up->encap_destroy);
2003                if (encap_destroy)
2004                        encap_destroy(sk);
2005        }
2006}
2007
2008/*
2009 *      Socket option code for UDP
2010 */
2011int udp_lib_setsockopt(struct sock *sk, int level, int optname,
2012                       char __user *optval, unsigned int optlen,
2013                       int (*push_pending_frames)(struct sock *))
2014{
2015        struct udp_sock *up = udp_sk(sk);
2016        int val, valbool;
2017        int err = 0;
2018        int is_udplite = IS_UDPLITE(sk);
2019
2020        if (optlen < sizeof(int))
2021                return -EINVAL;
2022
2023        if (get_user(val, (int __user *)optval))
2024                return -EFAULT;
2025
2026        valbool = val ? 1 : 0;
2027
2028        switch (optname) {
2029        case UDP_CORK:
2030                if (val != 0) {
2031                        up->corkflag = 1;
2032                } else {
2033                        up->corkflag = 0;
2034                        lock_sock(sk);
2035                        (*push_pending_frames)(sk);
2036                        release_sock(sk);
2037                }
2038                break;
2039
2040        case UDP_ENCAP:
2041                switch (val) {
2042                case 0:
2043                case UDP_ENCAP_ESPINUDP:
2044                case UDP_ENCAP_ESPINUDP_NON_IKE:
2045                        up->encap_rcv = xfrm4_udp_encap_rcv;
2046                        /* FALLTHROUGH */
2047                case UDP_ENCAP_L2TPINUDP:
2048                        up->encap_type = val;
2049                        udp_encap_enable();
2050                        break;
2051                default:
2052                        err = -ENOPROTOOPT;
2053                        break;
2054                }
2055                break;
2056
2057        case UDP_NO_CHECK6_TX:
2058                up->no_check6_tx = valbool;
2059                break;
2060
2061        case UDP_NO_CHECK6_RX:
2062                up->no_check6_rx = valbool;
2063                break;
2064
2065        /*
2066         *      UDP-Lite's partial checksum coverage (RFC 3828).
2067         */
2068        /* The sender sets actual checksum coverage length via this option.
2069         * The case coverage > packet length is handled by send module. */
2070        case UDPLITE_SEND_CSCOV:
2071                if (!is_udplite)         /* Disable the option on UDP sockets */
2072                        return -ENOPROTOOPT;
2073                if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2074                        val = 8;
2075                else if (val > USHRT_MAX)
2076                        val = USHRT_MAX;
2077                up->pcslen = val;
2078                up->pcflag |= UDPLITE_SEND_CC;
2079                break;
2080
2081        /* The receiver specifies a minimum checksum coverage value. To make
2082         * sense, this should be set to at least 8 (as done below). If zero is
2083         * used, this again means full checksum coverage.                     */
2084        case UDPLITE_RECV_CSCOV:
2085                if (!is_udplite)         /* Disable the option on UDP sockets */
2086                        return -ENOPROTOOPT;
2087                if (val != 0 && val < 8) /* Avoid silly minimal values.       */
2088                        val = 8;
2089                else if (val > USHRT_MAX)
2090                        val = USHRT_MAX;
2091                up->pcrlen = val;
2092                up->pcflag |= UDPLITE_RECV_CC;
2093                break;
2094
2095        default:
2096                err = -ENOPROTOOPT;
2097                break;
2098        }
2099
2100        return err;
2101}
2102EXPORT_SYMBOL(udp_lib_setsockopt);
2103
2104int udp_setsockopt(struct sock *sk, int level, int optname,
2105                   char __user *optval, unsigned int optlen)
2106{
2107        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2108                return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2109                                          udp_push_pending_frames);
2110        return ip_setsockopt(sk, level, optname, optval, optlen);
2111}
2112
2113#ifdef CONFIG_COMPAT
2114int compat_udp_setsockopt(struct sock *sk, int level, int optname,
2115                          char __user *optval, unsigned int optlen)
2116{
2117        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2118                return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2119                                          udp_push_pending_frames);
2120        return compat_ip_setsockopt(sk, level, optname, optval, optlen);
2121}
2122#endif
2123
2124int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2125                       char __user *optval, int __user *optlen)
2126{
2127        struct udp_sock *up = udp_sk(sk);
2128        int val, len;
2129
2130        if (get_user(len, optlen))
2131                return -EFAULT;
2132
2133        len = min_t(unsigned int, len, sizeof(int));
2134
2135        if (len < 0)
2136                return -EINVAL;
2137
2138        switch (optname) {
2139        case UDP_CORK:
2140                val = up->corkflag;
2141                break;
2142
2143        case UDP_ENCAP:
2144                val = up->encap_type;
2145                break;
2146
2147        case UDP_NO_CHECK6_TX:
2148                val = up->no_check6_tx;
2149                break;
2150
2151        case UDP_NO_CHECK6_RX:
2152                val = up->no_check6_rx;
2153                break;
2154
2155        /* The following two cannot be changed on UDP sockets, the return is
2156         * always 0 (which corresponds to the full checksum coverage of UDP). */
2157        case UDPLITE_SEND_CSCOV:
2158                val = up->pcslen;
2159                break;
2160
2161        case UDPLITE_RECV_CSCOV:
2162                val = up->pcrlen;
2163                break;
2164
2165        default:
2166                return -ENOPROTOOPT;
2167        }
2168
2169        if (put_user(len, optlen))
2170                return -EFAULT;
2171        if (copy_to_user(optval, &val, len))
2172                return -EFAULT;
2173        return 0;
2174}
2175EXPORT_SYMBOL(udp_lib_getsockopt);
2176
2177int udp_getsockopt(struct sock *sk, int level, int optname,
2178                   char __user *optval, int __user *optlen)
2179{
2180        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2181                return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2182        return ip_getsockopt(sk, level, optname, optval, optlen);
2183}
2184
2185#ifdef CONFIG_COMPAT
2186int compat_udp_getsockopt(struct sock *sk, int level, int optname,
2187                                 char __user *optval, int __user *optlen)
2188{
2189        if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2190                return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2191        return compat_ip_getsockopt(sk, level, optname, optval, optlen);
2192}
2193#endif
2194/**
2195 *      udp_poll - wait for a UDP event.
2196 *      @file - file struct
2197 *      @sock - socket
2198 *      @wait - poll table
2199 *
2200 *      This is same as datagram poll, except for the special case of
2201 *      blocking sockets. If application is using a blocking fd
2202 *      and a packet with checksum error is in the queue;
2203 *      then it could get return from select indicating data available
2204 *      but then block when reading it. Add special case code
2205 *      to work around these arguably broken applications.
2206 */
2207unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2208{
2209        unsigned int mask = datagram_poll(file, sock, wait);
2210        struct sock *sk = sock->sk;
2211
2212        sock_rps_record_flow(sk);
2213
2214        /* Check for false positives due to checksum errors */
2215        if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2216            !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
2217                mask &= ~(POLLIN | POLLRDNORM);
2218
2219        return mask;
2220
2221}
2222EXPORT_SYMBOL(udp_poll);
2223
2224struct proto udp_prot = {
2225        .name              = "UDP",
2226        .owner             = THIS_MODULE,
2227        .close             = udp_lib_close,
2228        .connect           = ip4_datagram_connect,
2229        .disconnect        = udp_disconnect,
2230        .ioctl             = udp_ioctl,
2231        .destroy           = udp_destroy_sock,
2232        .setsockopt        = udp_setsockopt,
2233        .getsockopt        = udp_getsockopt,
2234        .sendmsg           = udp_sendmsg,
2235        .recvmsg           = udp_recvmsg,
2236        .sendpage          = udp_sendpage,
2237        .backlog_rcv       = __udp_queue_rcv_skb,
2238        .release_cb        = ip4_datagram_release_cb,
2239        .hash              = udp_lib_hash,
2240        .unhash            = udp_lib_unhash,
2241        .rehash            = udp_v4_rehash,
2242        .get_port          = udp_v4_get_port,
2243        .memory_allocated  = &udp_memory_allocated,
2244        .sysctl_mem        = sysctl_udp_mem,
2245        .sysctl_wmem       = &sysctl_udp_wmem_min,
2246        .sysctl_rmem       = &sysctl_udp_rmem_min,
2247        .obj_size          = sizeof(struct udp_sock),
2248        .slab_flags        = SLAB_DESTROY_BY_RCU,
2249        .h.udp_table       = &udp_table,
2250#ifdef CONFIG_COMPAT
2251        .compat_setsockopt = compat_udp_setsockopt,
2252        .compat_getsockopt = compat_udp_getsockopt,
2253#endif
2254        .clear_sk          = sk_prot_clear_portaddr_nulls,
2255};
2256EXPORT_SYMBOL(udp_prot);
2257
2258/* ------------------------------------------------------------------------ */
2259#ifdef CONFIG_PROC_FS
2260
2261static struct sock *udp_get_first(struct seq_file *seq, int start)
2262{
2263        struct sock *sk;
2264        struct udp_iter_state *state = seq->private;
2265        struct net *net = seq_file_net(seq);
2266
2267        for (state->bucket = start; state->bucket <= state->udp_table->mask;
2268             ++state->bucket) {
2269                struct hlist_nulls_node *node;
2270                struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
2271
2272                if (hlist_nulls_empty(&hslot->head))
2273                        continue;
2274
2275                spin_lock_bh(&hslot->lock);
2276                sk_nulls_for_each(sk, node, &hslot->head) {
2277                        if (!net_eq(sock_net(sk), net))
2278                                continue;
2279                        if (sk->sk_family == state->family)
2280                                goto found;
2281                }
2282                spin_unlock_bh(&hslot->lock);
2283        }
2284        sk = NULL;
2285found:
2286        return sk;
2287}
2288
2289static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
2290{
2291        struct udp_iter_state *state = seq->private;
2292        struct net *net = seq_file_net(seq);
2293
2294        do {
2295                sk = sk_nulls_next(sk);
2296        } while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2297
2298        if (!sk) {
2299                if (state->bucket <= state->udp_table->mask)
2300                        spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2301                return udp_get_first(seq, state->bucket + 1);
2302        }
2303        return sk;
2304}
2305
2306static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2307{
2308        struct sock *sk = udp_get_first(seq, 0);
2309
2310        if (sk)
2311                while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2312                        --pos;
2313        return pos ? NULL : sk;
2314}
2315
2316static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2317{
2318        struct udp_iter_state *state = seq->private;
2319        state->bucket = MAX_UDP_PORTS;
2320
2321        return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2322}
2323
2324static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2325{
2326        struct sock *sk;
2327
2328        if (v == SEQ_START_TOKEN)
2329                sk = udp_get_idx(seq, 0);
2330        else
2331                sk = udp_get_next(seq, v);
2332
2333        ++*pos;
2334        return sk;
2335}
2336
2337static void udp_seq_stop(struct seq_file *seq, void *v)
2338{
2339        struct udp_iter_state *state = seq->private;
2340
2341        if (state->bucket <= state->udp_table->mask)
2342                spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2343}
2344
2345int udp_seq_open(struct inode *inode, struct file *file)
2346{
2347        struct udp_seq_afinfo *afinfo = PDE_DATA(inode);
2348        struct udp_iter_state *s;
2349        int err;
2350
2351        err = seq_open_net(inode, file, &afinfo->seq_ops,
2352                           sizeof(struct udp_iter_state));
2353        if (err < 0)
2354                return err;
2355
2356        s = ((struct seq_file *)file->private_data)->private;
2357        s->family               = afinfo->family;
2358        s->udp_table            = afinfo->udp_table;
2359        return err;
2360}
2361EXPORT_SYMBOL(udp_seq_open);
2362
2363/* ------------------------------------------------------------------------ */
2364int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2365{
2366        struct proc_dir_entry *p;
2367        int rc = 0;
2368
2369        afinfo->seq_ops.start           = udp_seq_start;
2370        afinfo->seq_ops.next            = udp_seq_next;
2371        afinfo->seq_ops.stop            = udp_seq_stop;
2372
2373        p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2374                             afinfo->seq_fops, afinfo);
2375        if (!p)
2376                rc = -ENOMEM;
2377        return rc;
2378}
2379EXPORT_SYMBOL(udp_proc_register);
2380
2381void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2382{
2383        remove_proc_entry(afinfo->name, net->proc_net);
2384}
2385EXPORT_SYMBOL(udp_proc_unregister);
2386
2387/* ------------------------------------------------------------------------ */
2388static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2389                int bucket)
2390{
2391        struct inet_sock *inet = inet_sk(sp);
2392        __be32 dest = inet->inet_daddr;
2393        __be32 src  = inet->inet_rcv_saddr;
2394        __u16 destp       = ntohs(inet->inet_dport);
2395        __u16 srcp        = ntohs(inet->inet_sport);
2396
2397        seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2398                " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
2399                bucket, src, srcp, dest, destp, sp->sk_state,
2400                sk_wmem_alloc_get(sp),
2401                sk_rmem_alloc_get(sp),
2402                0, 0L, 0,
2403                from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
2404                0, sock_i_ino(sp),
2405                atomic_read(&sp->sk_refcnt), sp,
2406                atomic_read(&sp->sk_drops));
2407}
2408
2409int udp4_seq_show(struct seq_file *seq, void *v)
2410{
2411        seq_setwidth(seq, 127);
2412        if (v == SEQ_START_TOKEN)
2413                seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
2414                           "rx_queue tr tm->when retrnsmt   uid  timeout "
2415                           "inode ref pointer drops");
2416        else {
2417                struct udp_iter_state *state = seq->private;
2418
2419                udp4_format_sock(v, seq, state->bucket);
2420        }
2421        seq_pad(seq, '\n');
2422        return 0;
2423}
2424
2425static const struct file_operations udp_afinfo_seq_fops = {
2426        .owner    = THIS_MODULE,
2427        .open     = udp_seq_open,
2428        .read     = seq_read,
2429        .llseek   = seq_lseek,
2430        .release  = seq_release_net
2431};
2432
2433/* ------------------------------------------------------------------------ */
2434static struct udp_seq_afinfo udp4_seq_afinfo = {
2435        .name           = "udp",
2436        .family         = AF_INET,
2437        .udp_table      = &udp_table,
2438        .seq_fops       = &udp_afinfo_seq_fops,
2439        .seq_ops        = {
2440                .show           = udp4_seq_show,
2441        },
2442};
2443
2444static int __net_init udp4_proc_init_net(struct net *net)
2445{
2446        return udp_proc_register(net, &udp4_seq_afinfo);
2447}
2448
2449static void __net_exit udp4_proc_exit_net(struct net *net)
2450{
2451        udp_proc_unregister(net, &udp4_seq_afinfo);
2452}
2453
2454static struct pernet_operations udp4_net_ops = {
2455        .init = udp4_proc_init_net,
2456        .exit = udp4_proc_exit_net,
2457};
2458
2459int __init udp4_proc_init(void)
2460{
2461        return register_pernet_subsys(&udp4_net_ops);
2462}
2463
2464void udp4_proc_exit(void)
2465{
2466        unregister_pernet_subsys(&udp4_net_ops);
2467}
2468#endif /* CONFIG_PROC_FS */
2469
2470static __initdata unsigned long uhash_entries;
2471static int __init set_uhash_entries(char *str)
2472{
2473        ssize_t ret;
2474
2475        if (!str)
2476                return 0;
2477
2478        ret = kstrtoul(str, 0, &uhash_entries);
2479        if (ret)
2480                return 0;
2481
2482        if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2483                uhash_entries = UDP_HTABLE_SIZE_MIN;
2484        return 1;
2485}
2486__setup("uhash_entries=", set_uhash_entries);
2487
2488void __init udp_table_init(struct udp_table *table, const char *name)
2489{
2490        unsigned int i;
2491
2492        table->hash = alloc_large_system_hash(name,
2493                                              2 * sizeof(struct udp_hslot),
2494                                              uhash_entries,
2495                                              21, /* one slot per 2 MB */
2496                                              0,
2497                                              &table->log,
2498                                              &table->mask,
2499                                              UDP_HTABLE_SIZE_MIN,
2500                                              64 * 1024);
2501
2502        table->hash2 = table->hash + (table->mask + 1);
2503        for (i = 0; i <= table->mask; i++) {
2504                INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2505                table->hash[i].count = 0;
2506                spin_lock_init(&table->hash[i].lock);
2507        }
2508        for (i = 0; i <= table->mask; i++) {
2509                INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2510                table->hash2[i].count = 0;
2511                spin_lock_init(&table->hash2[i].lock);
2512        }
2513}
2514
2515void __init udp_init(void)
2516{
2517        unsigned long limit;
2518
2519        udp_table_init(&udp_table, "UDP");
2520        limit = nr_free_buffer_pages() / 8;
2521        limit = max(limit, 128UL);
2522        sysctl_udp_mem[0] = limit / 4 * 3;
2523        sysctl_udp_mem[1] = limit;
2524        sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2525
2526        sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2527        sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2528}
2529
2530struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
2531                                       netdev_features_t features)
2532{
2533        struct sk_buff *segs = ERR_PTR(-EINVAL);
2534        u16 mac_offset = skb->mac_header;
2535        int mac_len = skb->mac_len;
2536        int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
2537        __be16 protocol = skb->protocol;
2538        netdev_features_t enc_features;
2539        int udp_offset, outer_hlen;
2540        unsigned int oldlen;
2541        bool need_csum;
2542
2543        oldlen = (u16)~skb->len;
2544
2545        if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
2546                goto out;
2547
2548        skb->encapsulation = 0;
2549        __skb_pull(skb, tnl_hlen);
2550        skb_reset_mac_header(skb);
2551        skb_set_network_header(skb, skb_inner_network_offset(skb));
2552        skb->mac_len = skb_inner_network_offset(skb);
2553        skb->protocol = htons(ETH_P_TEB);
2554
2555        need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
2556        if (need_csum)
2557                skb->encap_hdr_csum = 1;
2558
2559        /* segment inner packet. */
2560        enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
2561        segs = skb_mac_gso_segment(skb, enc_features);
2562        if (!segs || IS_ERR(segs)) {
2563                skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
2564                                     mac_len);
2565                goto out;
2566        }
2567
2568        outer_hlen = skb_tnl_header_len(skb);
2569        udp_offset = outer_hlen - tnl_hlen;
2570        skb = segs;
2571        do {
2572                struct udphdr *uh;
2573                int len;
2574
2575                skb_reset_inner_headers(skb);
2576                skb->encapsulation = 1;
2577
2578                skb->mac_len = mac_len;
2579
2580                skb_push(skb, outer_hlen);
2581                skb_reset_mac_header(skb);
2582                skb_set_network_header(skb, mac_len);
2583                skb_set_transport_header(skb, udp_offset);
2584                len = skb->len - udp_offset;
2585                uh = udp_hdr(skb);
2586                uh->len = htons(len);
2587
2588                if (need_csum) {
2589                        __be32 delta = htonl(oldlen + len);
2590
2591                        uh->check = ~csum_fold((__force __wsum)
2592                                               ((__force u32)uh->check +
2593                                                (__force u32)delta));
2594                        uh->check = gso_make_checksum(skb, ~uh->check);
2595
2596                        if (uh->check == 0)
2597                                uh->check = CSUM_MANGLED_0;
2598                }
2599
2600                skb->protocol = protocol;
2601        } while ((skb = skb->next));
2602out:
2603        return segs;
2604}
2605