net/mptcp/sockopt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Multipath TCP
   3  *
   4  * Copyright (c) 2021, Red Hat.
   5  */
   6
   7 #define pr_fmt(fmt) "MPTCP: " fmt
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <net/sock.h>
  12 #include <net/protocol.h>
  13 #include <net/tcp.h>
  14 #include <net/mptcp.h>
  15 #include "protocol.h"
  16
  17 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
  18 {
  19         sock_owned_by_me((const struct sock *)msk);
  20
  21         if (likely(!__mptcp_check_fallback(msk)))
  22                 return NULL;
  23
  24         return msk->first;
  25 }
  26
  27 static u32 sockopt_seq_reset(const struct sock *sk)
  28 {
  29         sock_owned_by_me(sk);
  30
  31         /* Highbits contain state.  Allows to distinguish sockopt_seq
  32          * of listener and established:
  33          * s0 = new_listener()
  34          * sockopt(s0) - seq is 1
  35          * s1 = accept(s0) - s1 inherits seq 1 if listener sk (s0)
  36          * sockopt(s0) - seq increments to 2 on s0
  37          * sockopt(s1) // seq increments to 2 on s1 (different option)
  38          * new ssk completes join, inherits options from s0 // seq 2
  39          * Needs sync from mptcp join logic, but ssk->seq == msk->seq
  40          *
  41          * Set High order bits to sk_state so ssk->seq == msk->seq test
  42          * will fail.
  43          */
  44
  45         return (u32)sk->sk_state << 24u;
  46 }
  47
  48 static void sockopt_seq_inc(struct mptcp_sock *msk)
  49 {
  50         u32 seq = (msk->setsockopt_seq + 1) & 0x00ffffff;
  51
  52         msk->setsockopt_seq = sockopt_seq_reset((struct sock *)msk) + seq;
  53 }
  54
  55 static int mptcp_get_int_option(struct mptcp_sock *msk, sockptr_t optval,
  56                                 unsigned int optlen, int *val)
  57 {
  58         if (optlen < sizeof(int))
  59                 return -EINVAL;
  60
  61         if (copy_from_sockptr(val, optval, sizeof(*val)))
  62                 return -EFAULT;
  63
  64         return 0;
  65 }
  66
  67 static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, int val)
  68 {
  69         struct mptcp_subflow_context *subflow;
  70         struct sock *sk = (struct sock *)msk;
  71
  72         lock_sock(sk);
  73         sockopt_seq_inc(msk);
  74
  75         mptcp_for_each_subflow(msk, subflow) {
  76                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
  77                 bool slow = lock_sock_fast(ssk);
  78
  79                 switch (optname) {
  80                 case SO_DEBUG:
  81                         sock_valbool_flag(ssk, SOCK_DBG, !!val);
  82                         break;
  83                 case SO_KEEPALIVE:
  84                         if (ssk->sk_prot->keepalive)
  85                                 ssk->sk_prot->keepalive(ssk, !!val);
  86                         sock_valbool_flag(ssk, SOCK_KEEPOPEN, !!val);
  87                         break;
  88                 case SO_PRIORITY:
  89                         ssk->sk_priority = val;
  90                         break;
  91                 case SO_SNDBUF:
  92                 case SO_SNDBUFFORCE:
  93                         ssk->sk_userlocks |= SOCK_SNDBUF_LOCK;
  94                         WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
  95                         break;
  96                 case SO_RCVBUF:
  97                 case SO_RCVBUFFORCE:
  98                         ssk->sk_userlocks |= SOCK_RCVBUF_LOCK;
  99                         WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
 100                         break;
 101                 case SO_MARK:
 102                         if (READ_ONCE(ssk->sk_mark) != sk->sk_mark) {
 103                                 ssk->sk_mark = sk->sk_mark;
 104                                 sk_dst_reset(ssk);
 105                         }
 106                         break;
 107                 case SO_INCOMING_CPU:
 108                         WRITE_ONCE(ssk->sk_incoming_cpu, val);
 109                         break;
 110                 }
 111
 112                 subflow->setsockopt_seq = msk->setsockopt_seq;
 113                 unlock_sock_fast(ssk, slow);
 114         }
 115
 116         release_sock(sk);
 117 }
 118
 119 static int mptcp_sol_socket_intval(struct mptcp_sock *msk, int optname, int val)
 120 {
 121         sockptr_t optval = KERNEL_SOCKPTR(&val);
 122         struct sock *sk = (struct sock *)msk;
 123         int ret;
 124
 125         ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
 126                               optval, sizeof(val));
 127         if (ret)
 128                 return ret;
 129
 130         mptcp_sol_socket_sync_intval(msk, optname, val);
 131         return 0;
 132 }
 133
 134 static void mptcp_so_incoming_cpu(struct mptcp_sock *msk, int val)
 135 {
 136         struct sock *sk = (struct sock *)msk;
 137
 138         WRITE_ONCE(sk->sk_incoming_cpu, val);
 139
 140         mptcp_sol_socket_sync_intval(msk, SO_INCOMING_CPU, val);
 141 }
 142
 143 static int mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optname, int val)
 144 {
 145         sockptr_t optval = KERNEL_SOCKPTR(&val);
 146         struct mptcp_subflow_context *subflow;
 147         struct sock *sk = (struct sock *)msk;
 148         int ret;
 149
 150         ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
 151                               optval, sizeof(val));
 152         if (ret)
 153                 return ret;
 154
 155         lock_sock(sk);
 156         mptcp_for_each_subflow(msk, subflow) {
 157                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 158                 bool slow = lock_sock_fast(ssk);
 159
 160                 sock_set_timestamp(sk, optname, !!val);
 161                 unlock_sock_fast(ssk, slow);
 162         }
 163
 164         release_sock(sk);
 165         return 0;
 166 }
 167
 168 static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
 169                                            sockptr_t optval,
 170                                            unsigned int optlen)
 171 {
 172         int val, ret;
 173
 174         ret = mptcp_get_int_option(msk, optval, optlen, &val);
 175         if (ret)
 176                 return ret;
 177
 178         switch (optname) {
 179         case SO_KEEPALIVE:
 180                 mptcp_sol_socket_sync_intval(msk, optname, val);
 181                 return 0;
 182         case SO_DEBUG:
 183         case SO_MARK:
 184         case SO_PRIORITY:
 185         case SO_SNDBUF:
 186         case SO_SNDBUFFORCE:
 187         case SO_RCVBUF:
 188         case SO_RCVBUFFORCE:
 189                 return mptcp_sol_socket_intval(msk, optname, val);
 190         case SO_INCOMING_CPU:
 191                 mptcp_so_incoming_cpu(msk, val);
 192                 return 0;
 193         case SO_TIMESTAMP_OLD:
 194         case SO_TIMESTAMP_NEW:
 195         case SO_TIMESTAMPNS_OLD:
 196         case SO_TIMESTAMPNS_NEW:
 197                 return mptcp_setsockopt_sol_socket_tstamp(msk, optname, val);
 198         }
 199
 200         return -ENOPROTOOPT;
 201 }
 202
 203 static int mptcp_setsockopt_sol_socket_timestamping(struct mptcp_sock *msk,
 204                                                     int optname,
 205                                                     sockptr_t optval,
 206                                                     unsigned int optlen)
 207 {
 208         struct mptcp_subflow_context *subflow;
 209         struct sock *sk = (struct sock *)msk;
 210         struct so_timestamping timestamping;
 211         int ret;
 212
 213         if (optlen == sizeof(timestamping)) {
 214                 if (copy_from_sockptr(&timestamping, optval,
 215                                       sizeof(timestamping)))
 216                         return -EFAULT;
 217         } else if (optlen == sizeof(int)) {
 218                 memset(&timestamping, 0, sizeof(timestamping));
 219
 220                 if (copy_from_sockptr(&timestamping.flags, optval, sizeof(int)))
 221                         return -EFAULT;
 222         } else {
 223                 return -EINVAL;
 224         }
 225
 226         ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname,
 227                               KERNEL_SOCKPTR(&timestamping),
 228                               sizeof(timestamping));
 229         if (ret)
 230                 return ret;
 231
 232         lock_sock(sk);
 233
 234         mptcp_for_each_subflow(msk, subflow) {
 235                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 236                 bool slow = lock_sock_fast(ssk);
 237
 238                 sock_set_timestamping(sk, optname, timestamping);
 239                 unlock_sock_fast(ssk, slow);
 240         }
 241
 242         release_sock(sk);
 243
 244         return 0;
 245 }
 246
 247 static int mptcp_setsockopt_sol_socket_linger(struct mptcp_sock *msk, sockptr_t optval,
 248                                               unsigned int optlen)
 249 {
 250         struct mptcp_subflow_context *subflow;
 251         struct sock *sk = (struct sock *)msk;
 252         struct linger ling;
 253         sockptr_t kopt;
 254         int ret;
 255
 256         if (optlen < sizeof(ling))
 257                 return -EINVAL;
 258
 259         if (copy_from_sockptr(&ling, optval, sizeof(ling)))
 260                 return -EFAULT;
 261
 262         kopt = KERNEL_SOCKPTR(&ling);
 263         ret = sock_setsockopt(sk->sk_socket, SOL_SOCKET, SO_LINGER, kopt, sizeof(ling));
 264         if (ret)
 265                 return ret;
 266
 267         lock_sock(sk);
 268         sockopt_seq_inc(msk);
 269         mptcp_for_each_subflow(msk, subflow) {
 270                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 271                 bool slow = lock_sock_fast(ssk);
 272
 273                 if (!ling.l_onoff) {
 274                         sock_reset_flag(ssk, SOCK_LINGER);
 275                 } else {
 276                         ssk->sk_lingertime = sk->sk_lingertime;
 277                         sock_set_flag(ssk, SOCK_LINGER);
 278                 }
 279
 280                 subflow->setsockopt_seq = msk->setsockopt_seq;
 281                 unlock_sock_fast(ssk, slow);
 282         }
 283
 284         release_sock(sk);
 285         return 0;
 286 }
 287
 288 static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
 289                                        sockptr_t optval, unsigned int optlen)
 290 {
 291         struct sock *sk = (struct sock *)msk;
 292         struct socket *ssock;
 293         int ret;
 294
 295         switch (optname) {
 296         case SO_REUSEPORT:
 297         case SO_REUSEADDR:
 298         case SO_BINDTODEVICE:
 299         case SO_BINDTOIFINDEX:
 300                 lock_sock(sk);
 301                 ssock = __mptcp_nmpc_socket(msk);
 302                 if (!ssock) {
 303                         release_sock(sk);
 304                         return -EINVAL;
 305                 }
 306
 307                 ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
 308                 if (ret == 0) {
 309                         if (optname == SO_REUSEPORT)
 310                                 sk->sk_reuseport = ssock->sk->sk_reuseport;
 311                         else if (optname == SO_REUSEADDR)
 312                                 sk->sk_reuse = ssock->sk->sk_reuse;
 313                         else if (optname == SO_BINDTODEVICE)
 314                                 sk->sk_bound_dev_if = ssock->sk->sk_bound_dev_if;
 315                         else if (optname == SO_BINDTOIFINDEX)
 316                                 sk->sk_bound_dev_if = ssock->sk->sk_bound_dev_if;
 317                 }
 318                 release_sock(sk);
 319                 return ret;
 320         case SO_KEEPALIVE:
 321         case SO_PRIORITY:
 322         case SO_SNDBUF:
 323         case SO_SNDBUFFORCE:
 324         case SO_RCVBUF:
 325         case SO_RCVBUFFORCE:
 326         case SO_MARK:
 327         case SO_INCOMING_CPU:
 328         case SO_DEBUG:
 329         case SO_TIMESTAMP_OLD:
 330         case SO_TIMESTAMP_NEW:
 331         case SO_TIMESTAMPNS_OLD:
 332         case SO_TIMESTAMPNS_NEW:
 333                 return mptcp_setsockopt_sol_socket_int(msk, optname, optval,
 334                                                        optlen);
 335         case SO_TIMESTAMPING_OLD:
 336         case SO_TIMESTAMPING_NEW:
 337                 return mptcp_setsockopt_sol_socket_timestamping(msk, optname,
 338                                                                 optval, optlen);
 339         case SO_LINGER:
 340                 return mptcp_setsockopt_sol_socket_linger(msk, optval, optlen);
 341         case SO_RCVLOWAT:
 342         case SO_RCVTIMEO_OLD:
 343         case SO_RCVTIMEO_NEW:
 344         case SO_BUSY_POLL:
 345         case SO_PREFER_BUSY_POLL:
 346         case SO_BUSY_POLL_BUDGET:
 347                 /* No need to copy: only relevant for msk */
 348                 return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
 349         case SO_NO_CHECK:
 350         case SO_DONTROUTE:
 351         case SO_BROADCAST:
 352         case SO_BSDCOMPAT:
 353         case SO_PASSCRED:
 354         case SO_PASSSEC:
 355         case SO_RXQ_OVFL:
 356         case SO_WIFI_STATUS:
 357         case SO_NOFCS:
 358         case SO_SELECT_ERR_QUEUE:
 359                 return 0;
 360         }
 361
 362         /* SO_OOBINLINE is not supported, let's avoid the related mess
 363          * SO_ATTACH_FILTER, SO_ATTACH_BPF, SO_ATTACH_REUSEPORT_CBPF,
 364          * SO_DETACH_REUSEPORT_BPF, SO_DETACH_FILTER, SO_LOCK_FILTER,
 365          * we must be careful with subflows
 366          *
 367          * SO_ATTACH_REUSEPORT_EBPF is not supported, at it checks
 368          * explicitly the sk_protocol field
 369          *
 370          * SO_PEEK_OFF is unsupported, as it is for plain TCP
 371          * SO_MAX_PACING_RATE is unsupported, we must be careful with subflows
 372          * SO_CNX_ADVICE is currently unsupported, could possibly be relevant,
 373          * but likely needs careful design
 374          *
 375          * SO_ZEROCOPY is currently unsupported, TODO in sndmsg
 376          * SO_TXTIME is currently unsupported
 377          */
 378
 379         return -EOPNOTSUPP;
 380 }
 381
 382 static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
 383                                sockptr_t optval, unsigned int optlen)
 384 {
 385         struct sock *sk = (struct sock *)msk;
 386         int ret = -EOPNOTSUPP;
 387         struct socket *ssock;
 388
 389         switch (optname) {
 390         case IPV6_V6ONLY:
 391                 lock_sock(sk);
 392                 ssock = __mptcp_nmpc_socket(msk);
 393                 if (!ssock) {
 394                         release_sock(sk);
 395                         return -EINVAL;
 396                 }
 397
 398                 ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
 399                 if (ret == 0)
 400                         sk->sk_ipv6only = ssock->sk->sk_ipv6only;
 401
 402                 release_sock(sk);
 403                 break;
 404         }
 405
 406         return ret;
 407 }
 408
 409 static bool mptcp_supported_sockopt(int level, int optname)
 410 {
 411         if (level == SOL_IP) {
 412                 switch (optname) {
 413                 /* should work fine */
 414                 case IP_FREEBIND:
 415                 case IP_TRANSPARENT:
 416
 417                 /* the following are control cmsg related */
 418                 case IP_PKTINFO:
 419                 case IP_RECVTTL:
 420                 case IP_RECVTOS:
 421                 case IP_RECVOPTS:
 422                 case IP_RETOPTS:
 423                 case IP_PASSSEC:
 424                 case IP_RECVORIGDSTADDR:
 425                 case IP_CHECKSUM:
 426                 case IP_RECVFRAGSIZE:
 427
 428                 /* common stuff that need some love */
 429                 case IP_TOS:
 430                 case IP_TTL:
 431                 case IP_BIND_ADDRESS_NO_PORT:
 432                 case IP_MTU_DISCOVER:
 433                 case IP_RECVERR:
 434
 435                 /* possibly less common may deserve some love */
 436                 case IP_MINTTL:
 437
 438                 /* the following is apparently a no-op for plain TCP */
 439                 case IP_RECVERR_RFC4884:
 440                         return true;
 441                 }
 442
 443                 /* IP_OPTIONS is not supported, needs subflow care */
 444                 /* IP_HDRINCL, IP_NODEFRAG are not supported, RAW specific */
 445                 /* IP_MULTICAST_TTL, IP_MULTICAST_LOOP, IP_UNICAST_IF,
 446                  * IP_ADD_MEMBERSHIP, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_MEMBERSHIP,
 447                  * IP_DROP_SOURCE_MEMBERSHIP, IP_BLOCK_SOURCE, IP_UNBLOCK_SOURCE,
 448                  * MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP MCAST_JOIN_SOURCE_GROUP,
 449                  * MCAST_LEAVE_SOURCE_GROUP, MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE,
 450                  * MCAST_MSFILTER, IP_MULTICAST_ALL are not supported, better not deal
 451                  * with mcast stuff
 452                  */
 453                 /* IP_IPSEC_POLICY, IP_XFRM_POLICY are nut supported, unrelated here */
 454                 return false;
 455         }
 456         if (level == SOL_IPV6) {
 457                 switch (optname) {
 458                 case IPV6_V6ONLY:
 459
 460                 /* the following are control cmsg related */
 461                 case IPV6_RECVPKTINFO:
 462                 case IPV6_2292PKTINFO:
 463                 case IPV6_RECVHOPLIMIT:
 464                 case IPV6_2292HOPLIMIT:
 465                 case IPV6_RECVRTHDR:
 466                 case IPV6_2292RTHDR:
 467                 case IPV6_RECVHOPOPTS:
 468                 case IPV6_2292HOPOPTS:
 469                 case IPV6_RECVDSTOPTS:
 470                 case IPV6_2292DSTOPTS:
 471                 case IPV6_RECVTCLASS:
 472                 case IPV6_FLOWINFO:
 473                 case IPV6_RECVPATHMTU:
 474                 case IPV6_RECVORIGDSTADDR:
 475                 case IPV6_RECVFRAGSIZE:
 476
 477                 /* the following ones need some love but are quite common */
 478                 case IPV6_TCLASS:
 479                 case IPV6_TRANSPARENT:
 480                 case IPV6_FREEBIND:
 481                 case IPV6_PKTINFO:
 482                 case IPV6_2292PKTOPTIONS:
 483                 case IPV6_UNICAST_HOPS:
 484                 case IPV6_MTU_DISCOVER:
 485                 case IPV6_MTU:
 486                 case IPV6_RECVERR:
 487                 case IPV6_FLOWINFO_SEND:
 488                 case IPV6_FLOWLABEL_MGR:
 489                 case IPV6_MINHOPCOUNT:
 490                 case IPV6_DONTFRAG:
 491                 case IPV6_AUTOFLOWLABEL:
 492
 493                 /* the following one is a no-op for plain TCP */
 494                 case IPV6_RECVERR_RFC4884:
 495                         return true;
 496                 }
 497
 498                 /* IPV6_HOPOPTS, IPV6_RTHDRDSTOPTS, IPV6_RTHDR, IPV6_DSTOPTS are
 499                  * not supported
 500                  */
 501                 /* IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_IF,
 502                  * IPV6_MULTICAST_IF, IPV6_ADDRFORM,
 503                  * IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP, IPV6_JOIN_ANYCAST,
 504                  * IPV6_LEAVE_ANYCAST, IPV6_MULTICAST_ALL, MCAST_JOIN_GROUP, MCAST_LEAVE_GROUP,
 505                  * MCAST_JOIN_SOURCE_GROUP, MCAST_LEAVE_SOURCE_GROUP,
 506                  * MCAST_BLOCK_SOURCE, MCAST_UNBLOCK_SOURCE, MCAST_MSFILTER
 507                  * are not supported better not deal with mcast
 508                  */
 509                 /* IPV6_ROUTER_ALERT, IPV6_ROUTER_ALERT_ISOLATE are not supported, since are evil */
 510
 511                 /* IPV6_IPSEC_POLICY, IPV6_XFRM_POLICY are not supported */
 512                 /* IPV6_ADDR_PREFERENCES is not supported, we must be careful with subflows */
 513                 return false;
 514         }
 515         if (level == SOL_TCP) {
 516                 switch (optname) {
 517                 /* the following are no-op or should work just fine */
 518                 case TCP_THIN_DUPACK:
 519                 case TCP_DEFER_ACCEPT:
 520
 521                 /* the following need some love */
 522                 case TCP_MAXSEG:
 523                 case TCP_NODELAY:
 524                 case TCP_THIN_LINEAR_TIMEOUTS:
 525                 case TCP_CONGESTION:
 526                 case TCP_ULP:
 527                 case TCP_CORK:
 528                 case TCP_KEEPIDLE:
 529                 case TCP_KEEPINTVL:
 530                 case TCP_KEEPCNT:
 531                 case TCP_SYNCNT:
 532                 case TCP_SAVE_SYN:
 533                 case TCP_LINGER2:
 534                 case TCP_WINDOW_CLAMP:
 535                 case TCP_QUICKACK:
 536                 case TCP_USER_TIMEOUT:
 537                 case TCP_TIMESTAMP:
 538                 case TCP_NOTSENT_LOWAT:
 539                 case TCP_TX_DELAY:
 540                         return true;
 541                 }
 542
 543                 /* TCP_MD5SIG, TCP_MD5SIG_EXT are not supported, MD5 is not compatible with MPTCP */
 544
 545                 /* TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS,
 546                  * TCP_REPAIR_WINDOW are not supported, better avoid this mess
 547                  */
 548                 /* TCP_FASTOPEN_KEY, TCP_FASTOPEN TCP_FASTOPEN_CONNECT, TCP_FASTOPEN_NO_COOKIE,
 549                  * are not supported fastopen is currently unsupported
 550                  */
 551                 /* TCP_INQ is currently unsupported, needs some recvmsg work */
 552         }
 553         return false;
 554 }
 555
 556 static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t optval,
 557                                                unsigned int optlen)
 558 {
 559         struct mptcp_subflow_context *subflow;
 560         struct sock *sk = (struct sock *)msk;
 561         char name[TCP_CA_NAME_MAX];
 562         bool cap_net_admin;
 563         int ret;
 564
 565         if (optlen < 1)
 566                 return -EINVAL;
 567
 568         ret = strncpy_from_sockptr(name, optval,
 569                                    min_t(long, TCP_CA_NAME_MAX - 1, optlen));
 570         if (ret < 0)
 571                 return -EFAULT;
 572
 573         name[ret] = 0;
 574
 575         cap_net_admin = ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN);
 576
 577         ret = 0;
 578         lock_sock(sk);
 579         sockopt_seq_inc(msk);
 580         mptcp_for_each_subflow(msk, subflow) {
 581                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 582                 int err;
 583
 584                 lock_sock(ssk);
 585                 err = tcp_set_congestion_control(ssk, name, true, cap_net_admin);
 586                 if (err < 0 && ret == 0)
 587                         ret = err;
 588                 subflow->setsockopt_seq = msk->setsockopt_seq;
 589                 release_sock(ssk);
 590         }
 591
 592         if (ret == 0)
 593                 strcpy(msk->ca_name, name);
 594
 595         release_sock(sk);
 596         return ret;
 597 }
 598
 599 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 600                                     sockptr_t optval, unsigned int optlen)
 601 {
 602         switch (optname) {
 603         case TCP_ULP:
 604                 return -EOPNOTSUPP;
 605         case TCP_CONGESTION:
 606                 return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen);
 607         }
 608
 609         return -EOPNOTSUPP;
 610 }
 611
 612 int mptcp_setsockopt(struct sock *sk, int level, int optname,
 613                      sockptr_t optval, unsigned int optlen)
 614 {
 615         struct mptcp_sock *msk = mptcp_sk(sk);
 616         struct sock *ssk;
 617
 618         pr_debug("msk=%p", msk);
 619
 620         if (level == SOL_SOCKET)
 621                 return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
 622
 623         if (!mptcp_supported_sockopt(level, optname))
 624                 return -ENOPROTOOPT;
 625
 626         /* @@ the meaning of setsockopt() when the socket is connected and
 627          * there are multiple subflows is not yet defined. It is up to the
 628          * MPTCP-level socket to configure the subflows until the subflow
 629          * is in TCP fallback, when TCP socket options are passed through
 630          * to the one remaining subflow.
 631          */
 632         lock_sock(sk);
 633         ssk = __mptcp_tcp_fallback(msk);
 634         release_sock(sk);
 635         if (ssk)
 636                 return tcp_setsockopt(ssk, level, optname, optval, optlen);
 637
 638         if (level == SOL_IPV6)
 639                 return mptcp_setsockopt_v6(msk, optname, optval, optlen);
 640
 641         if (level == SOL_TCP)
 642                 return mptcp_setsockopt_sol_tcp(msk, optname, optval, optlen);
 643
 644         return -EOPNOTSUPP;
 645 }
 646
 647 static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
 648                                           char __user *optval, int __user *optlen)
 649 {
 650         struct sock *sk = (struct sock *)msk;
 651         struct socket *ssock;
 652         int ret = -EINVAL;
 653         struct sock *ssk;
 654
 655         lock_sock(sk);
 656         ssk = msk->first;
 657         if (ssk) {
 658                 ret = tcp_getsockopt(ssk, level, optname, optval, optlen);
 659                 goto out;
 660         }
 661
 662         ssock = __mptcp_nmpc_socket(msk);
 663         if (!ssock)
 664                 goto out;
 665
 666         ret = tcp_getsockopt(ssock->sk, level, optname, optval, optlen);
 667
 668 out:
 669         release_sock(sk);
 670         return ret;
 671 }
 672
 673 static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 674                                     char __user *optval, int __user *optlen)
 675 {
 676         switch (optname) {
 677         case TCP_ULP:
 678         case TCP_CONGESTION:
 679         case TCP_INFO:
 680         case TCP_CC_INFO:
 681                 return mptcp_getsockopt_first_sf_only(msk, SOL_TCP, optname,
 682                                                       optval, optlen);
 683         }
 684         return -EOPNOTSUPP;
 685 }
 686
 687 int mptcp_getsockopt(struct sock *sk, int level, int optname,
 688                      char __user *optval, int __user *option)
 689 {
 690         struct mptcp_sock *msk = mptcp_sk(sk);
 691         struct sock *ssk;
 692
 693         pr_debug("msk=%p", msk);
 694
 695         /* @@ the meaning of setsockopt() when the socket is connected and
 696          * there are multiple subflows is not yet defined. It is up to the
 697          * MPTCP-level socket to configure the subflows until the subflow
 698          * is in TCP fallback, when socket options are passed through
 699          * to the one remaining subflow.
 700          */
 701         lock_sock(sk);
 702         ssk = __mptcp_tcp_fallback(msk);
 703         release_sock(sk);
 704         if (ssk)
 705                 return tcp_getsockopt(ssk, level, optname, optval, option);
 706
 707         if (level == SOL_TCP)
 708                 return mptcp_getsockopt_sol_tcp(msk, optname, optval, option);
 709         return -EOPNOTSUPP;
 710 }
 711
 712 static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 713 {
 714         static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
 715         struct sock *sk = (struct sock *)msk;
 716
 717         if (ssk->sk_prot->keepalive) {
 718                 if (sock_flag(sk, SOCK_KEEPOPEN))
 719                         ssk->sk_prot->keepalive(ssk, 1);
 720                 else
 721                         ssk->sk_prot->keepalive(ssk, 0);
 722         }
 723
 724         ssk->sk_priority = sk->sk_priority;
 725         ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
 726         ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
 727
 728         if (sk->sk_userlocks & tx_rx_locks) {
 729                 ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
 730                 if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
 731                         WRITE_ONCE(ssk->sk_sndbuf, sk->sk_sndbuf);
 732                 if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
 733                         WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf);
 734         }
 735
 736         if (sock_flag(sk, SOCK_LINGER)) {
 737                 ssk->sk_lingertime = sk->sk_lingertime;
 738                 sock_set_flag(ssk, SOCK_LINGER);
 739         } else {
 740                 sock_reset_flag(ssk, SOCK_LINGER);
 741         }
 742
 743         if (sk->sk_mark != ssk->sk_mark) {
 744                 ssk->sk_mark = sk->sk_mark;
 745                 sk_dst_reset(ssk);
 746         }
 747
 748         sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
 749
 750         if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
 751                 tcp_set_congestion_control(ssk, msk->ca_name, false, true);
 752 }
 753
 754 static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
 755 {
 756         bool slow = lock_sock_fast(ssk);
 757
 758         sync_socket_options(msk, ssk);
 759
 760         unlock_sock_fast(ssk, slow);
 761 }
 762
 763 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
 764 {
 765         struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 766
 767         msk_owned_by_me(msk);
 768
 769         if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
 770                 __mptcp_sockopt_sync(msk, ssk);
 771
 772                 subflow->setsockopt_seq = msk->setsockopt_seq;
 773         }
 774 }
 775
 776 void mptcp_sockopt_sync_all(struct mptcp_sock *msk)
 777 {
 778         struct mptcp_subflow_context *subflow;
 779         struct sock *sk = (struct sock *)msk;
 780         u32 seq;
 781
 782         seq = sockopt_seq_reset(sk);
 783
 784         mptcp_for_each_subflow(msk, subflow) {
 785                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 786                 u32 sseq = READ_ONCE(subflow->setsockopt_seq);
 787
 788                 if (sseq != msk->setsockopt_seq) {
 789                         __mptcp_sockopt_sync(msk, ssk);
 790                         WRITE_ONCE(subflow->setsockopt_seq, seq);
 791                 } else if (sseq != seq) {
 792                         WRITE_ONCE(subflow->setsockopt_seq, seq);
 793                 }
 794
 795                 cond_resched();
 796         }
 797
 798         msk->setsockopt_seq = seq;
 799 }