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