net/kcm/kcmsock.c

   1 /*
   2  * Kernel Connection Multiplexor
   3  *
   4  * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/bpf.h>
  12 #include <linux/errno.h>
  13 #include <linux/errqueue.h>
  14 #include <linux/file.h>
  15 #include <linux/in.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/net.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/poll.h>
  21 #include <linux/rculist.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/socket.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/workqueue.h>
  26 #include <net/kcm.h>
  27 #include <net/netns/generic.h>
  28 #include <net/sock.h>
  29 #include <uapi/linux/kcm.h>
  30
  31 unsigned int kcm_net_id;
  32
  33 static struct kmem_cache *kcm_psockp __read_mostly;
  34 static struct kmem_cache *kcm_muxp __read_mostly;
  35 static struct workqueue_struct *kcm_wq;
  36
  37 static inline struct kcm_sock *kcm_sk(const struct sock *sk)
  38 {
  39         return (struct kcm_sock *)sk;
  40 }
  41
  42 static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb)
  43 {
  44         return (struct kcm_tx_msg *)skb->cb;
  45 }
  46
  47 static void report_csk_error(struct sock *csk, int err)
  48 {
  49         csk->sk_err = EPIPE;
  50         csk->sk_error_report(csk);
  51 }
  52
  53 static void kcm_abort_tx_psock(struct kcm_psock *psock, int err,
  54                                bool wakeup_kcm)
  55 {
  56         struct sock *csk = psock->sk;
  57         struct kcm_mux *mux = psock->mux;
  58
  59         /* Unrecoverable error in transmit */
  60
  61         spin_lock_bh(&mux->lock);
  62
  63         if (psock->tx_stopped) {
  64                 spin_unlock_bh(&mux->lock);
  65                 return;
  66         }
  67
  68         psock->tx_stopped = 1;
  69         KCM_STATS_INCR(psock->stats.tx_aborts);
  70
  71         if (!psock->tx_kcm) {
  72                 /* Take off psocks_avail list */
  73                 list_del(&psock->psock_avail_list);
  74         } else if (wakeup_kcm) {
  75                 /* In this case psock is being aborted while outside of
  76                  * write_msgs and psock is reserved. Schedule tx_work
  77                  * to handle the failure there. Need to commit tx_stopped
  78                  * before queuing work.
  79                  */
  80                 smp_mb();
  81
  82                 queue_work(kcm_wq, &psock->tx_kcm->tx_work);
  83         }
  84
  85         spin_unlock_bh(&mux->lock);
  86
  87         /* Report error on lower socket */
  88         report_csk_error(csk, err);
  89 }
  90
  91 /* RX mux lock held. */
  92 static void kcm_update_rx_mux_stats(struct kcm_mux *mux,
  93                                     struct kcm_psock *psock)
  94 {
  95         STRP_STATS_ADD(mux->stats.rx_bytes,
  96                        psock->strp.stats.rx_bytes -
  97                        psock->saved_rx_bytes);
  98         mux->stats.rx_msgs +=
  99                 psock->strp.stats.rx_msgs - psock->saved_rx_msgs;
 100         psock->saved_rx_msgs = psock->strp.stats.rx_msgs;
 101         psock->saved_rx_bytes = psock->strp.stats.rx_bytes;
 102 }
 103
 104 static void kcm_update_tx_mux_stats(struct kcm_mux *mux,
 105                                     struct kcm_psock *psock)
 106 {
 107         KCM_STATS_ADD(mux->stats.tx_bytes,
 108                       psock->stats.tx_bytes - psock->saved_tx_bytes);
 109         mux->stats.tx_msgs +=
 110                 psock->stats.tx_msgs - psock->saved_tx_msgs;
 111         psock->saved_tx_msgs = psock->stats.tx_msgs;
 112         psock->saved_tx_bytes = psock->stats.tx_bytes;
 113 }
 114
 115 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
 116
 117 /* KCM is ready to receive messages on its queue-- either the KCM is new or
 118  * has become unblocked after being blocked on full socket buffer. Queue any
 119  * pending ready messages on a psock. RX mux lock held.
 120  */
 121 static void kcm_rcv_ready(struct kcm_sock *kcm)
 122 {
 123         struct kcm_mux *mux = kcm->mux;
 124         struct kcm_psock *psock;
 125         struct sk_buff *skb;
 126
 127         if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled))
 128                 return;
 129
 130         while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) {
 131                 if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
 132                         /* Assuming buffer limit has been reached */
 133                         skb_queue_head(&mux->rx_hold_queue, skb);
 134                         WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
 135                         return;
 136                 }
 137         }
 138
 139         while (!list_empty(&mux->psocks_ready)) {
 140                 psock = list_first_entry(&mux->psocks_ready, struct kcm_psock,
 141                                          psock_ready_list);
 142
 143                 if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) {
 144                         /* Assuming buffer limit has been reached */
 145                         WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
 146                         return;
 147                 }
 148
 149                 /* Consumed the ready message on the psock. Schedule rx_work to
 150                  * get more messages.
 151                  */
 152                 list_del(&psock->psock_ready_list);
 153                 psock->ready_rx_msg = NULL;
 154                 /* Commit clearing of ready_rx_msg for queuing work */
 155                 smp_mb();
 156
 157                 strp_unpause(&psock->strp);
 158                 strp_check_rcv(&psock->strp);
 159         }
 160
 161         /* Buffer limit is okay now, add to ready list */
 162         list_add_tail(&kcm->wait_rx_list,
 163                       &kcm->mux->kcm_rx_waiters);
 164         kcm->rx_wait = true;
 165 }
 166
 167 static void kcm_rfree(struct sk_buff *skb)
 168 {
 169         struct sock *sk = skb->sk;
 170         struct kcm_sock *kcm = kcm_sk(sk);
 171         struct kcm_mux *mux = kcm->mux;
 172         unsigned int len = skb->truesize;
 173
 174         sk_mem_uncharge(sk, len);
 175         atomic_sub(len, &sk->sk_rmem_alloc);
 176
 177         /* For reading rx_wait and rx_psock without holding lock */
 178         smp_mb__after_atomic();
 179
 180         if (!kcm->rx_wait && !kcm->rx_psock &&
 181             sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
 182                 spin_lock_bh(&mux->rx_lock);
 183                 kcm_rcv_ready(kcm);
 184                 spin_unlock_bh(&mux->rx_lock);
 185         }
 186 }
 187
 188 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 189 {
 190         struct sk_buff_head *list = &sk->sk_receive_queue;
 191
 192         if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
 193                 return -ENOMEM;
 194
 195         if (!sk_rmem_schedule(sk, skb, skb->truesize))
 196                 return -ENOBUFS;
 197
 198         skb->dev = NULL;
 199
 200         skb_orphan(skb);
 201         skb->sk = sk;
 202         skb->destructor = kcm_rfree;
 203         atomic_add(skb->truesize, &sk->sk_rmem_alloc);
 204         sk_mem_charge(sk, skb->truesize);
 205
 206         skb_queue_tail(list, skb);
 207
 208         if (!sock_flag(sk, SOCK_DEAD))
 209                 sk->sk_data_ready(sk);
 210
 211         return 0;
 212 }
 213
 214 /* Requeue received messages for a kcm socket to other kcm sockets. This is
 215  * called with a kcm socket is receive disabled.
 216  * RX mux lock held.
 217  */
 218 static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head)
 219 {
 220         struct sk_buff *skb;
 221         struct kcm_sock *kcm;
 222
 223         while ((skb = __skb_dequeue(head))) {
 224                 /* Reset destructor to avoid calling kcm_rcv_ready */
 225                 skb->destructor = sock_rfree;
 226                 skb_orphan(skb);
 227 try_again:
 228                 if (list_empty(&mux->kcm_rx_waiters)) {
 229                         skb_queue_tail(&mux->rx_hold_queue, skb);
 230                         continue;
 231                 }
 232
 233                 kcm = list_first_entry(&mux->kcm_rx_waiters,
 234                                        struct kcm_sock, wait_rx_list);
 235
 236                 if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
 237                         /* Should mean socket buffer full */
 238                         list_del(&kcm->wait_rx_list);
 239                         kcm->rx_wait = false;
 240
 241                         /* Commit rx_wait to read in kcm_free */
 242                         smp_wmb();
 243
 244                         goto try_again;
 245                 }
 246         }
 247 }
 248
 249 /* Lower sock lock held */
 250 static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock,
 251                                        struct sk_buff *head)
 252 {
 253         struct kcm_mux *mux = psock->mux;
 254         struct kcm_sock *kcm;
 255
 256         WARN_ON(psock->ready_rx_msg);
 257
 258         if (psock->rx_kcm)
 259                 return psock->rx_kcm;
 260
 261         spin_lock_bh(&mux->rx_lock);
 262
 263         if (psock->rx_kcm) {
 264                 spin_unlock_bh(&mux->rx_lock);
 265                 return psock->rx_kcm;
 266         }
 267
 268         kcm_update_rx_mux_stats(mux, psock);
 269
 270         if (list_empty(&mux->kcm_rx_waiters)) {
 271                 psock->ready_rx_msg = head;
 272                 strp_pause(&psock->strp);
 273                 list_add_tail(&psock->psock_ready_list,
 274                               &mux->psocks_ready);
 275                 spin_unlock_bh(&mux->rx_lock);
 276                 return NULL;
 277         }
 278
 279         kcm = list_first_entry(&mux->kcm_rx_waiters,
 280                                struct kcm_sock, wait_rx_list);
 281         list_del(&kcm->wait_rx_list);
 282         kcm->rx_wait = false;
 283
 284         psock->rx_kcm = kcm;
 285         kcm->rx_psock = psock;
 286
 287         spin_unlock_bh(&mux->rx_lock);
 288
 289         return kcm;
 290 }
 291
 292 static void kcm_done(struct kcm_sock *kcm);
 293
 294 static void kcm_done_work(struct work_struct *w)
 295 {
 296         kcm_done(container_of(w, struct kcm_sock, done_work));
 297 }
 298
 299 /* Lower sock held */
 300 static void unreserve_rx_kcm(struct kcm_psock *psock,
 301                              bool rcv_ready)
 302 {
 303         struct kcm_sock *kcm = psock->rx_kcm;
 304         struct kcm_mux *mux = psock->mux;
 305
 306         if (!kcm)
 307                 return;
 308
 309         spin_lock_bh(&mux->rx_lock);
 310
 311         psock->rx_kcm = NULL;
 312         kcm->rx_psock = NULL;
 313
 314         /* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with
 315          * kcm_rfree
 316          */
 317         smp_mb();
 318
 319         if (unlikely(kcm->done)) {
 320                 spin_unlock_bh(&mux->rx_lock);
 321
 322                 /* Need to run kcm_done in a task since we need to qcquire
 323                  * callback locks which may already be held here.
 324                  */
 325                 INIT_WORK(&kcm->done_work, kcm_done_work);
 326                 schedule_work(&kcm->done_work);
 327                 return;
 328         }
 329
 330         if (unlikely(kcm->rx_disabled)) {
 331                 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
 332         } else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) {
 333                 /* Check for degenerative race with rx_wait that all
 334                  * data was dequeued (accounted for in kcm_rfree).
 335                  */
 336                 kcm_rcv_ready(kcm);
 337         }
 338         spin_unlock_bh(&mux->rx_lock);
 339 }
 340
 341 /* Lower sock lock held */
 342 static void psock_data_ready(struct sock *sk)
 343 {
 344         struct kcm_psock *psock;
 345
 346         read_lock_bh(&sk->sk_callback_lock);
 347
 348         psock = (struct kcm_psock *)sk->sk_user_data;
 349         if (likely(psock))
 350                 strp_data_ready(&psock->strp);
 351
 352         read_unlock_bh(&sk->sk_callback_lock);
 353 }
 354
 355 /* Called with lower sock held */
 356 static void kcm_rcv_strparser(struct strparser *strp, struct sk_buff *skb)
 357 {
 358         struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
 359         struct kcm_sock *kcm;
 360
 361 try_queue:
 362         kcm = reserve_rx_kcm(psock, skb);
 363         if (!kcm) {
 364                  /* Unable to reserve a KCM, message is held in psock and strp
 365                   * is paused.
 366                   */
 367                 return;
 368         }
 369
 370         if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
 371                 /* Should mean socket buffer full */
 372                 unreserve_rx_kcm(psock, false);
 373                 goto try_queue;
 374         }
 375 }
 376
 377 static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb)
 378 {
 379         struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
 380         struct bpf_prog *prog = psock->bpf_prog;
 381
 382         return (*prog->bpf_func)(skb, prog->insnsi);
 383 }
 384
 385 static int kcm_read_sock_done(struct strparser *strp, int err)
 386 {
 387         struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
 388
 389         unreserve_rx_kcm(psock, true);
 390
 391         return err;
 392 }
 393
 394 static void psock_state_change(struct sock *sk)
 395 {
 396         /* TCP only does a POLLIN for a half close. Do a POLLHUP here
 397          * since application will normally not poll with POLLIN
 398          * on the TCP sockets.
 399          */
 400
 401         report_csk_error(sk, EPIPE);
 402 }
 403
 404 static void psock_write_space(struct sock *sk)
 405 {
 406         struct kcm_psock *psock;
 407         struct kcm_mux *mux;
 408         struct kcm_sock *kcm;
 409
 410         read_lock_bh(&sk->sk_callback_lock);
 411
 412         psock = (struct kcm_psock *)sk->sk_user_data;
 413         if (unlikely(!psock))
 414                 goto out;
 415         mux = psock->mux;
 416
 417         spin_lock_bh(&mux->lock);
 418
 419         /* Check if the socket is reserved so someone is waiting for sending. */
 420         kcm = psock->tx_kcm;
 421         if (kcm && !unlikely(kcm->tx_stopped))
 422                 queue_work(kcm_wq, &kcm->tx_work);
 423
 424         spin_unlock_bh(&mux->lock);
 425 out:
 426         read_unlock_bh(&sk->sk_callback_lock);
 427 }
 428
 429 static void unreserve_psock(struct kcm_sock *kcm);
 430
 431 /* kcm sock is locked. */
 432 static struct kcm_psock *reserve_psock(struct kcm_sock *kcm)
 433 {
 434         struct kcm_mux *mux = kcm->mux;
 435         struct kcm_psock *psock;
 436
 437         psock = kcm->tx_psock;
 438
 439         smp_rmb(); /* Must read tx_psock before tx_wait */
 440
 441         if (psock) {
 442                 WARN_ON(kcm->tx_wait);
 443                 if (unlikely(psock->tx_stopped))
 444                         unreserve_psock(kcm);
 445                 else
 446                         return kcm->tx_psock;
 447         }
 448
 449         spin_lock_bh(&mux->lock);
 450
 451         /* Check again under lock to see if psock was reserved for this
 452          * psock via psock_unreserve.
 453          */
 454         psock = kcm->tx_psock;
 455         if (unlikely(psock)) {
 456                 WARN_ON(kcm->tx_wait);
 457                 spin_unlock_bh(&mux->lock);
 458                 return kcm->tx_psock;
 459         }
 460
 461         if (!list_empty(&mux->psocks_avail)) {
 462                 psock = list_first_entry(&mux->psocks_avail,
 463                                          struct kcm_psock,
 464                                          psock_avail_list);
 465                 list_del(&psock->psock_avail_list);
 466                 if (kcm->tx_wait) {
 467                         list_del(&kcm->wait_psock_list);
 468                         kcm->tx_wait = false;
 469                 }
 470                 kcm->tx_psock = psock;
 471                 psock->tx_kcm = kcm;
 472                 KCM_STATS_INCR(psock->stats.reserved);
 473         } else if (!kcm->tx_wait) {
 474                 list_add_tail(&kcm->wait_psock_list,
 475                               &mux->kcm_tx_waiters);
 476                 kcm->tx_wait = true;
 477         }
 478
 479         spin_unlock_bh(&mux->lock);
 480
 481         return psock;
 482 }
 483
 484 /* mux lock held */
 485 static void psock_now_avail(struct kcm_psock *psock)
 486 {
 487         struct kcm_mux *mux = psock->mux;
 488         struct kcm_sock *kcm;
 489
 490         if (list_empty(&mux->kcm_tx_waiters)) {
 491                 list_add_tail(&psock->psock_avail_list,
 492                               &mux->psocks_avail);
 493         } else {
 494                 kcm = list_first_entry(&mux->kcm_tx_waiters,
 495                                        struct kcm_sock,
 496                                        wait_psock_list);
 497                 list_del(&kcm->wait_psock_list);
 498                 kcm->tx_wait = false;
 499                 psock->tx_kcm = kcm;
 500
 501                 /* Commit before changing tx_psock since that is read in
 502                  * reserve_psock before queuing work.
 503                  */
 504                 smp_mb();
 505
 506                 kcm->tx_psock = psock;
 507                 KCM_STATS_INCR(psock->stats.reserved);
 508                 queue_work(kcm_wq, &kcm->tx_work);
 509         }
 510 }
 511
 512 /* kcm sock is locked. */
 513 static void unreserve_psock(struct kcm_sock *kcm)
 514 {
 515         struct kcm_psock *psock;
 516         struct kcm_mux *mux = kcm->mux;
 517
 518         spin_lock_bh(&mux->lock);
 519
 520         psock = kcm->tx_psock;
 521
 522         if (WARN_ON(!psock)) {
 523                 spin_unlock_bh(&mux->lock);
 524                 return;
 525         }
 526
 527         smp_rmb(); /* Read tx_psock before tx_wait */
 528
 529         kcm_update_tx_mux_stats(mux, psock);
 530
 531         WARN_ON(kcm->tx_wait);
 532
 533         kcm->tx_psock = NULL;
 534         psock->tx_kcm = NULL;
 535         KCM_STATS_INCR(psock->stats.unreserved);
 536
 537         if (unlikely(psock->tx_stopped)) {
 538                 if (psock->done) {
 539                         /* Deferred free */
 540                         list_del(&psock->psock_list);
 541                         mux->psocks_cnt--;
 542                         sock_put(psock->sk);
 543                         fput(psock->sk->sk_socket->file);
 544                         kmem_cache_free(kcm_psockp, psock);
 545                 }
 546
 547                 /* Don't put back on available list */
 548
 549                 spin_unlock_bh(&mux->lock);
 550
 551                 return;
 552         }
 553
 554         psock_now_avail(psock);
 555
 556         spin_unlock_bh(&mux->lock);
 557 }
 558
 559 static void kcm_report_tx_retry(struct kcm_sock *kcm)
 560 {
 561         struct kcm_mux *mux = kcm->mux;
 562
 563         spin_lock_bh(&mux->lock);
 564         KCM_STATS_INCR(mux->stats.tx_retries);
 565         spin_unlock_bh(&mux->lock);
 566 }
 567
 568 /* Write any messages ready on the kcm socket.  Called with kcm sock lock
 569  * held.  Return bytes actually sent or error.
 570  */
 571 static int kcm_write_msgs(struct kcm_sock *kcm)
 572 {
 573         struct sock *sk = &kcm->sk;
 574         struct kcm_psock *psock;
 575         struct sk_buff *skb, *head;
 576         struct kcm_tx_msg *txm;
 577         unsigned short fragidx, frag_offset;
 578         unsigned int sent, total_sent = 0;
 579         int ret = 0;
 580
 581         kcm->tx_wait_more = false;
 582         psock = kcm->tx_psock;
 583         if (unlikely(psock && psock->tx_stopped)) {
 584                 /* A reserved psock was aborted asynchronously. Unreserve
 585                  * it and we'll retry the message.
 586                  */
 587                 unreserve_psock(kcm);
 588                 kcm_report_tx_retry(kcm);
 589                 if (skb_queue_empty(&sk->sk_write_queue))
 590                         return 0;
 591
 592                 kcm_tx_msg(skb_peek(&sk->sk_write_queue))->sent = 0;
 593
 594         } else if (skb_queue_empty(&sk->sk_write_queue)) {
 595                 return 0;
 596         }
 597
 598         head = skb_peek(&sk->sk_write_queue);
 599         txm = kcm_tx_msg(head);
 600
 601         if (txm->sent) {
 602                 /* Send of first skbuff in queue already in progress */
 603                 if (WARN_ON(!psock)) {
 604                         ret = -EINVAL;
 605                         goto out;
 606                 }
 607                 sent = txm->sent;
 608                 frag_offset = txm->frag_offset;
 609                 fragidx = txm->fragidx;
 610                 skb = txm->frag_skb;
 611
 612                 goto do_frag;
 613         }
 614
 615 try_again:
 616         psock = reserve_psock(kcm);
 617         if (!psock)
 618                 goto out;
 619
 620         do {
 621                 skb = head;
 622                 txm = kcm_tx_msg(head);
 623                 sent = 0;
 624
 625 do_frag_list:
 626                 if (WARN_ON(!skb_shinfo(skb)->nr_frags)) {
 627                         ret = -EINVAL;
 628                         goto out;
 629                 }
 630
 631                 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
 632                      fragidx++) {
 633                         skb_frag_t *frag;
 634
 635                         frag_offset = 0;
 636 do_frag:
 637                         frag = &skb_shinfo(skb)->frags[fragidx];
 638                         if (WARN_ON(!frag->size)) {
 639                                 ret = -EINVAL;
 640                                 goto out;
 641                         }
 642
 643                         ret = kernel_sendpage(psock->sk->sk_socket,
 644                                               frag->page.p,
 645                                               frag->page_offset + frag_offset,
 646                                               frag->size - frag_offset,
 647                                               MSG_DONTWAIT);
 648                         if (ret <= 0) {
 649                                 if (ret == -EAGAIN) {
 650                                         /* Save state to try again when there's
 651                                          * write space on the socket
 652                                          */
 653                                         txm->sent = sent;
 654                                         txm->frag_offset = frag_offset;
 655                                         txm->fragidx = fragidx;
 656                                         txm->frag_skb = skb;
 657
 658                                         ret = 0;
 659                                         goto out;
 660                                 }
 661
 662                                 /* Hard failure in sending message, abort this
 663                                  * psock since it has lost framing
 664                                  * synchonization and retry sending the
 665                                  * message from the beginning.
 666                                  */
 667                                 kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
 668                                                    true);
 669                                 unreserve_psock(kcm);
 670
 671                                 txm->sent = 0;
 672                                 kcm_report_tx_retry(kcm);
 673                                 ret = 0;
 674
 675                                 goto try_again;
 676                         }
 677
 678                         sent += ret;
 679                         frag_offset += ret;
 680                         KCM_STATS_ADD(psock->stats.tx_bytes, ret);
 681                         if (frag_offset < frag->size) {
 682                                 /* Not finished with this frag */
 683                                 goto do_frag;
 684                         }
 685                 }
 686
 687                 if (skb == head) {
 688                         if (skb_has_frag_list(skb)) {
 689                                 skb = skb_shinfo(skb)->frag_list;
 690                                 goto do_frag_list;
 691                         }
 692                 } else if (skb->next) {
 693                         skb = skb->next;
 694                         goto do_frag_list;
 695                 }
 696
 697                 /* Successfully sent the whole packet, account for it. */
 698                 skb_dequeue(&sk->sk_write_queue);
 699                 kfree_skb(head);
 700                 sk->sk_wmem_queued -= sent;
 701                 total_sent += sent;
 702                 KCM_STATS_INCR(psock->stats.tx_msgs);
 703         } while ((head = skb_peek(&sk->sk_write_queue)));
 704 out:
 705         if (!head) {
 706                 /* Done with all queued messages. */
 707                 WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
 708                 unreserve_psock(kcm);
 709         }
 710
 711         /* Check if write space is available */
 712         sk->sk_write_space(sk);
 713
 714         return total_sent ? : ret;
 715 }
 716
 717 static void kcm_tx_work(struct work_struct *w)
 718 {
 719         struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work);
 720         struct sock *sk = &kcm->sk;
 721         int err;
 722
 723         lock_sock(sk);
 724
 725         /* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx
 726          * aborts
 727          */
 728         err = kcm_write_msgs(kcm);
 729         if (err < 0) {
 730                 /* Hard failure in write, report error on KCM socket */
 731                 pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err);
 732                 report_csk_error(&kcm->sk, -err);
 733                 goto out;
 734         }
 735
 736         /* Primarily for SOCK_SEQPACKET sockets */
 737         if (likely(sk->sk_socket) &&
 738             test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
 739                 clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 740                 sk->sk_write_space(sk);
 741         }
 742
 743 out:
 744         release_sock(sk);
 745 }
 746
 747 static void kcm_push(struct kcm_sock *kcm)
 748 {
 749         if (kcm->tx_wait_more)
 750                 kcm_write_msgs(kcm);
 751 }
 752
 753 static ssize_t kcm_sendpage(struct socket *sock, struct page *page,
 754                             int offset, size_t size, int flags)
 755
 756 {
 757         struct sock *sk = sock->sk;
 758         struct kcm_sock *kcm = kcm_sk(sk);
 759         struct sk_buff *skb = NULL, *head = NULL;
 760         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 761         bool eor;
 762         int err = 0;
 763         int i;
 764
 765         if (flags & MSG_SENDPAGE_NOTLAST)
 766                 flags |= MSG_MORE;
 767
 768         /* No MSG_EOR from splice, only look at MSG_MORE */
 769         eor = !(flags & MSG_MORE);
 770
 771         lock_sock(sk);
 772
 773         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 774
 775         err = -EPIPE;
 776         if (sk->sk_err)
 777                 goto out_error;
 778
 779         if (kcm->seq_skb) {
 780                 /* Previously opened message */
 781                 head = kcm->seq_skb;
 782                 skb = kcm_tx_msg(head)->last_skb;
 783                 i = skb_shinfo(skb)->nr_frags;
 784
 785                 if (skb_can_coalesce(skb, i, page, offset)) {
 786                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
 787                         skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 788                         goto coalesced;
 789                 }
 790
 791                 if (i >= MAX_SKB_FRAGS) {
 792                         struct sk_buff *tskb;
 793
 794                         tskb = alloc_skb(0, sk->sk_allocation);
 795                         while (!tskb) {
 796                                 kcm_push(kcm);
 797                                 err = sk_stream_wait_memory(sk, &timeo);
 798                                 if (err)
 799                                         goto out_error;
 800                         }
 801
 802                         if (head == skb)
 803                                 skb_shinfo(head)->frag_list = tskb;
 804                         else
 805                                 skb->next = tskb;
 806
 807                         skb = tskb;
 808                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 809                         i = 0;
 810                 }
 811         } else {
 812                 /* Call the sk_stream functions to manage the sndbuf mem. */
 813                 if (!sk_stream_memory_free(sk)) {
 814                         kcm_push(kcm);
 815                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 816                         err = sk_stream_wait_memory(sk, &timeo);
 817                         if (err)
 818                                 goto out_error;
 819                 }
 820
 821                 head = alloc_skb(0, sk->sk_allocation);
 822                 while (!head) {
 823                         kcm_push(kcm);
 824                         err = sk_stream_wait_memory(sk, &timeo);
 825                         if (err)
 826                                 goto out_error;
 827                 }
 828
 829                 skb = head;
 830                 i = 0;
 831         }
 832
 833         get_page(page);
 834         skb_fill_page_desc(skb, i, page, offset, size);
 835         skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 836
 837 coalesced:
 838         skb->len += size;
 839         skb->data_len += size;
 840         skb->truesize += size;
 841         sk->sk_wmem_queued += size;
 842         sk_mem_charge(sk, size);
 843
 844         if (head != skb) {
 845                 head->len += size;
 846                 head->data_len += size;
 847                 head->truesize += size;
 848         }
 849
 850         if (eor) {
 851                 bool not_busy = skb_queue_empty(&sk->sk_write_queue);
 852
 853                 /* Message complete, queue it on send buffer */
 854                 __skb_queue_tail(&sk->sk_write_queue, head);
 855                 kcm->seq_skb = NULL;
 856                 KCM_STATS_INCR(kcm->stats.tx_msgs);
 857
 858                 if (flags & MSG_BATCH) {
 859                         kcm->tx_wait_more = true;
 860                 } else if (kcm->tx_wait_more || not_busy) {
 861                         err = kcm_write_msgs(kcm);
 862                         if (err < 0) {
 863                                 /* We got a hard error in write_msgs but have
 864                                  * already queued this message. Report an error
 865                                  * in the socket, but don't affect return value
 866                                  * from sendmsg
 867                                  */
 868                                 pr_warn("KCM: Hard failure on kcm_write_msgs\n");
 869                                 report_csk_error(&kcm->sk, -err);
 870                         }
 871                 }
 872         } else {
 873                 /* Message not complete, save state */
 874                 kcm->seq_skb = head;
 875                 kcm_tx_msg(head)->last_skb = skb;
 876         }
 877
 878         KCM_STATS_ADD(kcm->stats.tx_bytes, size);
 879
 880         release_sock(sk);
 881         return size;
 882
 883 out_error:
 884         kcm_push(kcm);
 885
 886         err = sk_stream_error(sk, flags, err);
 887
 888         /* make sure we wake any epoll edge trigger waiter */
 889         if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
 890                 sk->sk_write_space(sk);
 891
 892         release_sock(sk);
 893         return err;
 894 }
 895
 896 static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 897 {
 898         struct sock *sk = sock->sk;
 899         struct kcm_sock *kcm = kcm_sk(sk);
 900         struct sk_buff *skb = NULL, *head = NULL;
 901         size_t copy, copied = 0;
 902         long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 903         int eor = (sock->type == SOCK_DGRAM) ?
 904                   !(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR);
 905         int err = -EPIPE;
 906
 907         lock_sock(sk);
 908
 909         /* Per tcp_sendmsg this should be in poll */
 910         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 911
 912         if (sk->sk_err)
 913                 goto out_error;
 914
 915         if (kcm->seq_skb) {
 916                 /* Previously opened message */
 917                 head = kcm->seq_skb;
 918                 skb = kcm_tx_msg(head)->last_skb;
 919                 goto start;
 920         }
 921
 922         /* Call the sk_stream functions to manage the sndbuf mem. */
 923         if (!sk_stream_memory_free(sk)) {
 924                 kcm_push(kcm);
 925                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 926                 err = sk_stream_wait_memory(sk, &timeo);
 927                 if (err)
 928                         goto out_error;
 929         }
 930
 931         /* New message, alloc head skb */
 932         head = alloc_skb(0, sk->sk_allocation);
 933         while (!head) {
 934                 kcm_push(kcm);
 935                 err = sk_stream_wait_memory(sk, &timeo);
 936                 if (err)
 937                         goto out_error;
 938
 939                 head = alloc_skb(0, sk->sk_allocation);
 940         }
 941
 942         skb = head;
 943
 944         /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
 945          * csum_and_copy_from_iter from skb_do_copy_data_nocache.
 946          */
 947         skb->ip_summed = CHECKSUM_UNNECESSARY;
 948
 949 start:
 950         while (msg_data_left(msg)) {
 951                 bool merge = true;
 952                 int i = skb_shinfo(skb)->nr_frags;
 953                 struct page_frag *pfrag = sk_page_frag(sk);
 954
 955                 if (!sk_page_frag_refill(sk, pfrag))
 956                         goto wait_for_memory;
 957
 958                 if (!skb_can_coalesce(skb, i, pfrag->page,
 959                                       pfrag->offset)) {
 960                         if (i == MAX_SKB_FRAGS) {
 961                                 struct sk_buff *tskb;
 962
 963                                 tskb = alloc_skb(0, sk->sk_allocation);
 964                                 if (!tskb)
 965                                         goto wait_for_memory;
 966
 967                                 if (head == skb)
 968                                         skb_shinfo(head)->frag_list = tskb;
 969                                 else
 970                                         skb->next = tskb;
 971
 972                                 skb = tskb;
 973                                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 974                                 continue;
 975                         }
 976                         merge = false;
 977                 }
 978
 979                 copy = min_t(int, msg_data_left(msg),
 980                              pfrag->size - pfrag->offset);
 981
 982                 if (!sk_wmem_schedule(sk, copy))
 983                         goto wait_for_memory;
 984
 985                 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
 986                                                pfrag->page,
 987                                                pfrag->offset,
 988                                                copy);
 989                 if (err)
 990                         goto out_error;
 991
 992                 /* Update the skb. */
 993                 if (merge) {
 994                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 995                 } else {
 996                         skb_fill_page_desc(skb, i, pfrag->page,
 997                                            pfrag->offset, copy);
 998                         get_page(pfrag->page);
 999                 }
1000
1001                 pfrag->offset += copy;
1002                 copied += copy;
1003                 if (head != skb) {
1004                         head->len += copy;
1005                         head->data_len += copy;
1006                 }
1007
1008                 continue;
1009
1010 wait_for_memory:
1011                 kcm_push(kcm);
1012                 err = sk_stream_wait_memory(sk, &timeo);
1013                 if (err)
1014                         goto out_error;
1015         }
1016
1017         if (eor) {
1018                 bool not_busy = skb_queue_empty(&sk->sk_write_queue);
1019
1020                 /* Message complete, queue it on send buffer */
1021                 __skb_queue_tail(&sk->sk_write_queue, head);
1022                 kcm->seq_skb = NULL;
1023                 KCM_STATS_INCR(kcm->stats.tx_msgs);
1024
1025                 if (msg->msg_flags & MSG_BATCH) {
1026                         kcm->tx_wait_more = true;
1027                 } else if (kcm->tx_wait_more || not_busy) {
1028                         err = kcm_write_msgs(kcm);
1029                         if (err < 0) {
1030                                 /* We got a hard error in write_msgs but have
1031                                  * already queued this message. Report an error
1032                                  * in the socket, but don't affect return value
1033                                  * from sendmsg
1034                                  */
1035                                 pr_warn("KCM: Hard failure on kcm_write_msgs\n");
1036                                 report_csk_error(&kcm->sk, -err);
1037                         }
1038                 }
1039         } else {
1040                 /* Message not complete, save state */
1041 partial_message:
1042                 kcm->seq_skb = head;
1043                 kcm_tx_msg(head)->last_skb = skb;
1044         }
1045
1046         KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
1047
1048         release_sock(sk);
1049         return copied;
1050
1051 out_error:
1052         kcm_push(kcm);
1053
1054         if (copied && sock->type == SOCK_SEQPACKET) {
1055                 /* Wrote some bytes before encountering an
1056                  * error, return partial success.
1057                  */
1058                 goto partial_message;
1059         }
1060
1061         if (head != kcm->seq_skb)
1062                 kfree_skb(head);
1063
1064         err = sk_stream_error(sk, msg->msg_flags, err);
1065
1066         /* make sure we wake any epoll edge trigger waiter */
1067         if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1068                 sk->sk_write_space(sk);
1069
1070         release_sock(sk);
1071         return err;
1072 }
1073
1074 static struct sk_buff *kcm_wait_data(struct sock *sk, int flags,
1075                                      long timeo, int *err)
1076 {
1077         struct sk_buff *skb;
1078
1079         while (!(skb = skb_peek(&sk->sk_receive_queue))) {
1080                 if (sk->sk_err) {
1081                         *err = sock_error(sk);
1082                         return NULL;
1083                 }
1084
1085                 if (sock_flag(sk, SOCK_DONE))
1086                         return NULL;
1087
1088                 if ((flags & MSG_DONTWAIT) || !timeo) {
1089                         *err = -EAGAIN;
1090                         return NULL;
1091                 }
1092
1093                 sk_wait_data(sk, &timeo, NULL);
1094
1095                 /* Handle signals */
1096                 if (signal_pending(current)) {
1097                         *err = sock_intr_errno(timeo);
1098                         return NULL;
1099                 }
1100         }
1101
1102         return skb;
1103 }
1104
1105 static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
1106                        size_t len, int flags)
1107 {
1108         struct sock *sk = sock->sk;
1109         struct kcm_sock *kcm = kcm_sk(sk);
1110         int err = 0;
1111         long timeo;
1112         struct strp_rx_msg *rxm;
1113         int copied = 0;
1114         struct sk_buff *skb;
1115
1116         timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1117
1118         lock_sock(sk);
1119
1120         skb = kcm_wait_data(sk, flags, timeo, &err);
1121         if (!skb)
1122                 goto out;
1123
1124         /* Okay, have a message on the receive queue */
1125
1126         rxm = strp_rx_msg(skb);
1127
1128         if (len > rxm->full_len)
1129                 len = rxm->full_len;
1130
1131         err = skb_copy_datagram_msg(skb, rxm->offset, msg, len);
1132         if (err < 0)
1133                 goto out;
1134
1135         copied = len;
1136         if (likely(!(flags & MSG_PEEK))) {
1137                 KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1138                 if (copied < rxm->full_len) {
1139                         if (sock->type == SOCK_DGRAM) {
1140                                 /* Truncated message */
1141                                 msg->msg_flags |= MSG_TRUNC;
1142                                 goto msg_finished;
1143                         }
1144                         rxm->offset += copied;
1145                         rxm->full_len -= copied;
1146                 } else {
1147 msg_finished:
1148                         /* Finished with message */
1149                         msg->msg_flags |= MSG_EOR;
1150                         KCM_STATS_INCR(kcm->stats.rx_msgs);
1151                         skb_unlink(skb, &sk->sk_receive_queue);
1152                         kfree_skb(skb);
1153                 }
1154         }
1155
1156 out:
1157         release_sock(sk);
1158
1159         return copied ? : err;
1160 }
1161
1162 static ssize_t kcm_sock_splice(struct sock *sk,
1163                                struct pipe_inode_info *pipe,
1164                                struct splice_pipe_desc *spd)
1165 {
1166         int ret;
1167
1168         release_sock(sk);
1169         ret = splice_to_pipe(pipe, spd);
1170         lock_sock(sk);
1171
1172         return ret;
1173 }
1174
1175 static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
1176                                struct pipe_inode_info *pipe, size_t len,
1177                                unsigned int flags)
1178 {
1179         struct sock *sk = sock->sk;
1180         struct kcm_sock *kcm = kcm_sk(sk);
1181         long timeo;
1182         struct strp_rx_msg *rxm;
1183         int err = 0;
1184         ssize_t copied;
1185         struct sk_buff *skb;
1186
1187         /* Only support splice for SOCKSEQPACKET */
1188
1189         timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1190
1191         lock_sock(sk);
1192
1193         skb = kcm_wait_data(sk, flags, timeo, &err);
1194         if (!skb)
1195                 goto err_out;
1196
1197         /* Okay, have a message on the receive queue */
1198
1199         rxm = strp_rx_msg(skb);
1200
1201         if (len > rxm->full_len)
1202                 len = rxm->full_len;
1203
1204         copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
1205                                  kcm_sock_splice);
1206         if (copied < 0) {
1207                 err = copied;
1208                 goto err_out;
1209         }
1210
1211         KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1212
1213         rxm->offset += copied;
1214         rxm->full_len -= copied;
1215
1216         /* We have no way to return MSG_EOR. If all the bytes have been
1217          * read we still leave the message in the receive socket buffer.
1218          * A subsequent recvmsg needs to be done to return MSG_EOR and
1219          * finish reading the message.
1220          */
1221
1222         release_sock(sk);
1223
1224         return copied;
1225
1226 err_out:
1227         release_sock(sk);
1228
1229         return err;
1230 }
1231
1232 /* kcm sock lock held */
1233 static void kcm_recv_disable(struct kcm_sock *kcm)
1234 {
1235         struct kcm_mux *mux = kcm->mux;
1236
1237         if (kcm->rx_disabled)
1238                 return;
1239
1240         spin_lock_bh(&mux->rx_lock);
1241
1242         kcm->rx_disabled = 1;
1243
1244         /* If a psock is reserved we'll do cleanup in unreserve */
1245         if (!kcm->rx_psock) {
1246                 if (kcm->rx_wait) {
1247                         list_del(&kcm->wait_rx_list);
1248                         kcm->rx_wait = false;
1249                 }
1250
1251                 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
1252         }
1253
1254         spin_unlock_bh(&mux->rx_lock);
1255 }
1256
1257 /* kcm sock lock held */
1258 static void kcm_recv_enable(struct kcm_sock *kcm)
1259 {
1260         struct kcm_mux *mux = kcm->mux;
1261
1262         if (!kcm->rx_disabled)
1263                 return;
1264
1265         spin_lock_bh(&mux->rx_lock);
1266
1267         kcm->rx_disabled = 0;
1268         kcm_rcv_ready(kcm);
1269
1270         spin_unlock_bh(&mux->rx_lock);
1271 }
1272
1273 static int kcm_setsockopt(struct socket *sock, int level, int optname,
1274                           char __user *optval, unsigned int optlen)
1275 {
1276         struct kcm_sock *kcm = kcm_sk(sock->sk);
1277         int val, valbool;
1278         int err = 0;
1279
1280         if (level != SOL_KCM)
1281                 return -ENOPROTOOPT;
1282
1283         if (optlen < sizeof(int))
1284                 return -EINVAL;
1285
1286         if (get_user(val, (int __user *)optval))
1287                 return -EINVAL;
1288
1289         valbool = val ? 1 : 0;
1290
1291         switch (optname) {
1292         case KCM_RECV_DISABLE:
1293                 lock_sock(&kcm->sk);
1294                 if (valbool)
1295                         kcm_recv_disable(kcm);
1296                 else
1297                         kcm_recv_enable(kcm);
1298                 release_sock(&kcm->sk);
1299                 break;
1300         default:
1301                 err = -ENOPROTOOPT;
1302         }
1303
1304         return err;
1305 }
1306
1307 static int kcm_getsockopt(struct socket *sock, int level, int optname,
1308                           char __user *optval, int __user *optlen)
1309 {
1310         struct kcm_sock *kcm = kcm_sk(sock->sk);
1311         int val, len;
1312
1313         if (level != SOL_KCM)
1314                 return -ENOPROTOOPT;
1315
1316         if (get_user(len, optlen))
1317                 return -EFAULT;
1318
1319         len = min_t(unsigned int, len, sizeof(int));
1320         if (len < 0)
1321                 return -EINVAL;
1322
1323         switch (optname) {
1324         case KCM_RECV_DISABLE:
1325                 val = kcm->rx_disabled;
1326                 break;
1327         default:
1328                 return -ENOPROTOOPT;
1329         }
1330
1331         if (put_user(len, optlen))
1332                 return -EFAULT;
1333         if (copy_to_user(optval, &val, len))
1334                 return -EFAULT;
1335         return 0;
1336 }
1337
1338 static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux)
1339 {
1340         struct kcm_sock *tkcm;
1341         struct list_head *head;
1342         int index = 0;
1343
1344         /* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so
1345          * we set sk_state, otherwise epoll_wait always returns right away with
1346          * POLLHUP
1347          */
1348         kcm->sk.sk_state = TCP_ESTABLISHED;
1349
1350         /* Add to mux's kcm sockets list */
1351         kcm->mux = mux;
1352         spin_lock_bh(&mux->lock);
1353
1354         head = &mux->kcm_socks;
1355         list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) {
1356                 if (tkcm->index != index)
1357                         break;
1358                 head = &tkcm->kcm_sock_list;
1359                 index++;
1360         }
1361
1362         list_add(&kcm->kcm_sock_list, head);
1363         kcm->index = index;
1364
1365         mux->kcm_socks_cnt++;
1366         spin_unlock_bh(&mux->lock);
1367
1368         INIT_WORK(&kcm->tx_work, kcm_tx_work);
1369
1370         spin_lock_bh(&mux->rx_lock);
1371         kcm_rcv_ready(kcm);
1372         spin_unlock_bh(&mux->rx_lock);
1373 }
1374
1375 static int kcm_attach(struct socket *sock, struct socket *csock,
1376                       struct bpf_prog *prog)
1377 {
1378         struct kcm_sock *kcm = kcm_sk(sock->sk);
1379         struct kcm_mux *mux = kcm->mux;
1380         struct sock *csk;
1381         struct kcm_psock *psock = NULL, *tpsock;
1382         struct list_head *head;
1383         int index = 0;
1384         struct strp_callbacks cb;
1385         int err;
1386
1387         csk = csock->sk;
1388         if (!csk)
1389                 return -EINVAL;
1390
1391         psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
1392         if (!psock)
1393                 return -ENOMEM;
1394
1395         psock->mux = mux;
1396         psock->sk = csk;
1397         psock->bpf_prog = prog;
1398
1399         cb.rcv_msg = kcm_rcv_strparser;
1400         cb.abort_parser = NULL;
1401         cb.parse_msg = kcm_parse_func_strparser;
1402         cb.read_sock_done = kcm_read_sock_done;
1403
1404         err = strp_init(&psock->strp, csk, &cb);
1405         if (err) {
1406                 kmem_cache_free(kcm_psockp, psock);
1407                 return err;
1408         }
1409
1410         sock_hold(csk);
1411
1412         write_lock_bh(&csk->sk_callback_lock);
1413         psock->save_data_ready = csk->sk_data_ready;
1414         psock->save_write_space = csk->sk_write_space;
1415         psock->save_state_change = csk->sk_state_change;
1416         csk->sk_user_data = psock;
1417         csk->sk_data_ready = psock_data_ready;
1418         csk->sk_write_space = psock_write_space;
1419         csk->sk_state_change = psock_state_change;
1420         write_unlock_bh(&csk->sk_callback_lock);
1421
1422         /* Finished initialization, now add the psock to the MUX. */
1423         spin_lock_bh(&mux->lock);
1424         head = &mux->psocks;
1425         list_for_each_entry(tpsock, &mux->psocks, psock_list) {
1426                 if (tpsock->index != index)
1427                         break;
1428                 head = &tpsock->psock_list;
1429                 index++;
1430         }
1431
1432         list_add(&psock->psock_list, head);
1433         psock->index = index;
1434
1435         KCM_STATS_INCR(mux->stats.psock_attach);
1436         mux->psocks_cnt++;
1437         psock_now_avail(psock);
1438         spin_unlock_bh(&mux->lock);
1439
1440         /* Schedule RX work in case there are already bytes queued */
1441         strp_check_rcv(&psock->strp);
1442
1443         return 0;
1444 }
1445
1446 static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
1447 {
1448         struct socket *csock;
1449         struct bpf_prog *prog;
1450         int err;
1451
1452         csock = sockfd_lookup(info->fd, &err);
1453         if (!csock)
1454                 return -ENOENT;
1455
1456         prog = bpf_prog_get_type(info->bpf_fd, BPF_PROG_TYPE_SOCKET_FILTER);
1457         if (IS_ERR(prog)) {
1458                 err = PTR_ERR(prog);
1459                 goto out;
1460         }
1461
1462         err = kcm_attach(sock, csock, prog);
1463         if (err) {
1464                 bpf_prog_put(prog);
1465                 goto out;
1466         }
1467
1468         /* Keep reference on file also */
1469
1470         return 0;
1471 out:
1472         fput(csock->file);
1473         return err;
1474 }
1475
1476 static void kcm_unattach(struct kcm_psock *psock)
1477 {
1478         struct sock *csk = psock->sk;
1479         struct kcm_mux *mux = psock->mux;
1480
1481         lock_sock(csk);
1482
1483         /* Stop getting callbacks from TCP socket. After this there should
1484          * be no way to reserve a kcm for this psock.
1485          */
1486         write_lock_bh(&csk->sk_callback_lock);
1487         csk->sk_user_data = NULL;
1488         csk->sk_data_ready = psock->save_data_ready;
1489         csk->sk_write_space = psock->save_write_space;
1490         csk->sk_state_change = psock->save_state_change;
1491         strp_stop(&psock->strp);
1492
1493         if (WARN_ON(psock->rx_kcm)) {
1494                 write_unlock_bh(&csk->sk_callback_lock);
1495                 return;
1496         }
1497
1498         spin_lock_bh(&mux->rx_lock);
1499
1500         /* Stop receiver activities. After this point psock should not be
1501          * able to get onto ready list either through callbacks or work.
1502          */
1503         if (psock->ready_rx_msg) {
1504                 list_del(&psock->psock_ready_list);
1505                 kfree_skb(psock->ready_rx_msg);
1506                 psock->ready_rx_msg = NULL;
1507                 KCM_STATS_INCR(mux->stats.rx_ready_drops);
1508         }
1509
1510         spin_unlock_bh(&mux->rx_lock);
1511
1512         write_unlock_bh(&csk->sk_callback_lock);
1513
1514         /* Call strp_done without sock lock */
1515         release_sock(csk);
1516         strp_done(&psock->strp);
1517         lock_sock(csk);
1518
1519         bpf_prog_put(psock->bpf_prog);
1520
1521         spin_lock_bh(&mux->lock);
1522
1523         aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_stats);
1524         save_strp_stats(&psock->strp, &mux->aggregate_strp_stats);
1525
1526         KCM_STATS_INCR(mux->stats.psock_unattach);
1527
1528         if (psock->tx_kcm) {
1529                 /* psock was reserved.  Just mark it finished and we will clean
1530                  * up in the kcm paths, we need kcm lock which can not be
1531                  * acquired here.
1532                  */
1533                 KCM_STATS_INCR(mux->stats.psock_unattach_rsvd);
1534                 spin_unlock_bh(&mux->lock);
1535
1536                 /* We are unattaching a socket that is reserved. Abort the
1537                  * socket since we may be out of sync in sending on it. We need
1538                  * to do this without the mux lock.
1539                  */
1540                 kcm_abort_tx_psock(psock, EPIPE, false);
1541
1542                 spin_lock_bh(&mux->lock);
1543                 if (!psock->tx_kcm) {
1544                         /* psock now unreserved in window mux was unlocked */
1545                         goto no_reserved;
1546                 }
1547                 psock->done = 1;
1548
1549                 /* Commit done before queuing work to process it */
1550                 smp_mb();
1551
1552                 /* Queue tx work to make sure psock->done is handled */
1553                 queue_work(kcm_wq, &psock->tx_kcm->tx_work);
1554                 spin_unlock_bh(&mux->lock);
1555         } else {
1556 no_reserved:
1557                 if (!psock->tx_stopped)
1558                         list_del(&psock->psock_avail_list);
1559                 list_del(&psock->psock_list);
1560                 mux->psocks_cnt--;
1561                 spin_unlock_bh(&mux->lock);
1562
1563                 sock_put(csk);
1564                 fput(csk->sk_socket->file);
1565                 kmem_cache_free(kcm_psockp, psock);
1566         }
1567
1568         release_sock(csk);
1569 }
1570
1571 static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
1572 {
1573         struct kcm_sock *kcm = kcm_sk(sock->sk);
1574         struct kcm_mux *mux = kcm->mux;
1575         struct kcm_psock *psock;
1576         struct socket *csock;
1577         struct sock *csk;
1578         int err;
1579
1580         csock = sockfd_lookup(info->fd, &err);
1581         if (!csock)
1582                 return -ENOENT;
1583
1584         csk = csock->sk;
1585         if (!csk) {
1586                 err = -EINVAL;
1587                 goto out;
1588         }
1589
1590         err = -ENOENT;
1591
1592         spin_lock_bh(&mux->lock);
1593
1594         list_for_each_entry(psock, &mux->psocks, psock_list) {
1595                 if (psock->sk != csk)
1596                         continue;
1597
1598                 /* Found the matching psock */
1599
1600                 if (psock->unattaching || WARN_ON(psock->done)) {
1601                         err = -EALREADY;
1602                         break;
1603                 }
1604
1605                 psock->unattaching = 1;
1606
1607                 spin_unlock_bh(&mux->lock);
1608
1609                 /* Lower socket lock should already be held */
1610                 kcm_unattach(psock);
1611
1612                 err = 0;
1613                 goto out;
1614         }
1615
1616         spin_unlock_bh(&mux->lock);
1617
1618 out:
1619         fput(csock->file);
1620         return err;
1621 }
1622
1623 static struct proto kcm_proto = {
1624         .name   = "KCM",
1625         .owner  = THIS_MODULE,
1626         .obj_size = sizeof(struct kcm_sock),
1627 };
1628
1629 /* Clone a kcm socket. */
1630 static int kcm_clone(struct socket *osock, struct kcm_clone *info,
1631                      struct socket **newsockp)
1632 {
1633         struct socket *newsock;
1634         struct sock *newsk;
1635         struct file *newfile;
1636         int err, newfd;
1637
1638         err = -ENFILE;
1639         newsock = sock_alloc();
1640         if (!newsock)
1641                 goto out;
1642
1643         newsock->type = osock->type;
1644         newsock->ops = osock->ops;
1645
1646         __module_get(newsock->ops->owner);
1647
1648         newfd = get_unused_fd_flags(0);
1649         if (unlikely(newfd < 0)) {
1650                 err = newfd;
1651                 goto out_fd_fail;
1652         }
1653
1654         newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
1655         if (unlikely(IS_ERR(newfile))) {
1656                 err = PTR_ERR(newfile);
1657                 goto out_sock_alloc_fail;
1658         }
1659
1660         newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
1661                          &kcm_proto, true);
1662         if (!newsk) {
1663                 err = -ENOMEM;
1664                 goto out_sk_alloc_fail;
1665         }
1666
1667         sock_init_data(newsock, newsk);
1668         init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
1669
1670         fd_install(newfd, newfile);
1671         *newsockp = newsock;
1672         info->fd = newfd;
1673
1674         return 0;
1675
1676 out_sk_alloc_fail:
1677         fput(newfile);
1678 out_sock_alloc_fail:
1679         put_unused_fd(newfd);
1680 out_fd_fail:
1681         sock_release(newsock);
1682 out:
1683         return err;
1684 }
1685
1686 static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1687 {
1688         int err;
1689
1690         switch (cmd) {
1691         case SIOCKCMATTACH: {
1692                 struct kcm_attach info;
1693
1694                 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
1695                         err = -EFAULT;
1696
1697                 err = kcm_attach_ioctl(sock, &info);
1698
1699                 break;
1700         }
1701         case SIOCKCMUNATTACH: {
1702                 struct kcm_unattach info;
1703
1704                 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
1705                         err = -EFAULT;
1706
1707                 err = kcm_unattach_ioctl(sock, &info);
1708
1709                 break;
1710         }
1711         case SIOCKCMCLONE: {
1712                 struct kcm_clone info;
1713                 struct socket *newsock = NULL;
1714
1715                 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
1716                         err = -EFAULT;
1717
1718                 err = kcm_clone(sock, &info, &newsock);
1719
1720                 if (!err) {
1721                         if (copy_to_user((void __user *)arg, &info,
1722                                          sizeof(info))) {
1723                                 err = -EFAULT;
1724                                 sock_release(newsock);
1725                         }
1726                 }
1727
1728                 break;
1729         }
1730         default:
1731                 err = -ENOIOCTLCMD;
1732                 break;
1733         }
1734
1735         return err;
1736 }
1737
1738 static void free_mux(struct rcu_head *rcu)
1739 {
1740         struct kcm_mux *mux = container_of(rcu,
1741             struct kcm_mux, rcu);
1742
1743         kmem_cache_free(kcm_muxp, mux);
1744 }
1745
1746 static void release_mux(struct kcm_mux *mux)
1747 {
1748         struct kcm_net *knet = mux->knet;
1749         struct kcm_psock *psock, *tmp_psock;
1750
1751         /* Release psocks */
1752         list_for_each_entry_safe(psock, tmp_psock,
1753                                  &mux->psocks, psock_list) {
1754                 if (!WARN_ON(psock->unattaching))
1755                         kcm_unattach(psock);
1756         }
1757
1758         if (WARN_ON(mux->psocks_cnt))
1759                 return;
1760
1761         __skb_queue_purge(&mux->rx_hold_queue);
1762
1763         mutex_lock(&knet->mutex);
1764         aggregate_mux_stats(&mux->stats, &knet->aggregate_mux_stats);
1765         aggregate_psock_stats(&mux->aggregate_psock_stats,
1766                               &knet->aggregate_psock_stats);
1767         aggregate_strp_stats(&mux->aggregate_strp_stats,
1768                              &knet->aggregate_strp_stats);
1769         list_del_rcu(&mux->kcm_mux_list);
1770         knet->count--;
1771         mutex_unlock(&knet->mutex);
1772
1773         call_rcu(&mux->rcu, free_mux);
1774 }
1775
1776 static void kcm_done(struct kcm_sock *kcm)
1777 {
1778         struct kcm_mux *mux = kcm->mux;
1779         struct sock *sk = &kcm->sk;
1780         int socks_cnt;
1781
1782         spin_lock_bh(&mux->rx_lock);
1783         if (kcm->rx_psock) {
1784                 /* Cleanup in unreserve_rx_kcm */
1785                 WARN_ON(kcm->done);
1786                 kcm->rx_disabled = 1;
1787                 kcm->done = 1;
1788                 spin_unlock_bh(&mux->rx_lock);
1789                 return;
1790         }
1791
1792         if (kcm->rx_wait) {
1793                 list_del(&kcm->wait_rx_list);
1794                 kcm->rx_wait = false;
1795         }
1796         /* Move any pending receive messages to other kcm sockets */
1797         requeue_rx_msgs(mux, &sk->sk_receive_queue);
1798
1799         spin_unlock_bh(&mux->rx_lock);
1800
1801         if (WARN_ON(sk_rmem_alloc_get(sk)))
1802                 return;
1803
1804         /* Detach from MUX */
1805         spin_lock_bh(&mux->lock);
1806
1807         list_del(&kcm->kcm_sock_list);
1808         mux->kcm_socks_cnt--;
1809         socks_cnt = mux->kcm_socks_cnt;
1810
1811         spin_unlock_bh(&mux->lock);
1812
1813         if (!socks_cnt) {
1814                 /* We are done with the mux now. */
1815                 release_mux(mux);
1816         }
1817
1818         WARN_ON(kcm->rx_wait);
1819
1820         sock_put(&kcm->sk);
1821 }
1822
1823 /* Called by kcm_release to close a KCM socket.
1824  * If this is the last KCM socket on the MUX, destroy the MUX.
1825  */
1826 static int kcm_release(struct socket *sock)
1827 {
1828         struct sock *sk = sock->sk;
1829         struct kcm_sock *kcm;
1830         struct kcm_mux *mux;
1831         struct kcm_psock *psock;
1832
1833         if (!sk)
1834                 return 0;
1835
1836         kcm = kcm_sk(sk);
1837         mux = kcm->mux;
1838
1839         sock_orphan(sk);
1840         kfree_skb(kcm->seq_skb);
1841
1842         lock_sock(sk);
1843         /* Purge queue under lock to avoid race condition with tx_work trying
1844          * to act when queue is nonempty. If tx_work runs after this point
1845          * it will just return.
1846          */
1847         __skb_queue_purge(&sk->sk_write_queue);
1848
1849         /* Set tx_stopped. This is checked when psock is bound to a kcm and we
1850          * get a writespace callback. This prevents further work being queued
1851          * from the callback (unbinding the psock occurs after canceling work.
1852          */
1853         kcm->tx_stopped = 1;
1854
1855         release_sock(sk);
1856
1857         spin_lock_bh(&mux->lock);
1858         if (kcm->tx_wait) {
1859                 /* Take of tx_wait list, after this point there should be no way
1860                  * that a psock will be assigned to this kcm.
1861                  */
1862                 list_del(&kcm->wait_psock_list);
1863                 kcm->tx_wait = false;
1864         }
1865         spin_unlock_bh(&mux->lock);
1866
1867         /* Cancel work. After this point there should be no outside references
1868          * to the kcm socket.
1869          */
1870         cancel_work_sync(&kcm->tx_work);
1871
1872         lock_sock(sk);
1873         psock = kcm->tx_psock;
1874         if (psock) {
1875                 /* A psock was reserved, so we need to kill it since it
1876                  * may already have some bytes queued from a message. We
1877                  * need to do this after removing kcm from tx_wait list.
1878                  */
1879                 kcm_abort_tx_psock(psock, EPIPE, false);
1880                 unreserve_psock(kcm);
1881         }
1882         release_sock(sk);
1883
1884         WARN_ON(kcm->tx_wait);
1885         WARN_ON(kcm->tx_psock);
1886
1887         sock->sk = NULL;
1888
1889         kcm_done(kcm);
1890
1891         return 0;
1892 }
1893
1894 static const struct proto_ops kcm_dgram_ops = {
1895         .family =       PF_KCM,
1896         .owner =        THIS_MODULE,
1897         .release =      kcm_release,
1898         .bind =         sock_no_bind,
1899         .connect =      sock_no_connect,
1900         .socketpair =   sock_no_socketpair,
1901         .accept =       sock_no_accept,
1902         .getname =      sock_no_getname,
1903         .poll =         datagram_poll,
1904         .ioctl =        kcm_ioctl,
1905         .listen =       sock_no_listen,
1906         .shutdown =     sock_no_shutdown,
1907         .setsockopt =   kcm_setsockopt,
1908         .getsockopt =   kcm_getsockopt,
1909         .sendmsg =      kcm_sendmsg,
1910         .recvmsg =      kcm_recvmsg,
1911         .mmap =         sock_no_mmap,
1912         .sendpage =     kcm_sendpage,
1913 };
1914
1915 static const struct proto_ops kcm_seqpacket_ops = {
1916         .family =       PF_KCM,
1917         .owner =        THIS_MODULE,
1918         .release =      kcm_release,
1919         .bind =         sock_no_bind,
1920         .connect =      sock_no_connect,
1921         .socketpair =   sock_no_socketpair,
1922         .accept =       sock_no_accept,
1923         .getname =      sock_no_getname,
1924         .poll =         datagram_poll,
1925         .ioctl =        kcm_ioctl,
1926         .listen =       sock_no_listen,
1927         .shutdown =     sock_no_shutdown,
1928         .setsockopt =   kcm_setsockopt,
1929         .getsockopt =   kcm_getsockopt,
1930         .sendmsg =      kcm_sendmsg,
1931         .recvmsg =      kcm_recvmsg,
1932         .mmap =         sock_no_mmap,
1933         .sendpage =     kcm_sendpage,
1934         .splice_read =  kcm_splice_read,
1935 };
1936
1937 /* Create proto operation for kcm sockets */
1938 static int kcm_create(struct net *net, struct socket *sock,
1939                       int protocol, int kern)
1940 {
1941         struct kcm_net *knet = net_generic(net, kcm_net_id);
1942         struct sock *sk;
1943         struct kcm_mux *mux;
1944
1945         switch (sock->type) {
1946         case SOCK_DGRAM:
1947                 sock->ops = &kcm_dgram_ops;
1948                 break;
1949         case SOCK_SEQPACKET:
1950                 sock->ops = &kcm_seqpacket_ops;
1951                 break;
1952         default:
1953                 return -ESOCKTNOSUPPORT;
1954         }
1955
1956         if (protocol != KCMPROTO_CONNECTED)
1957                 return -EPROTONOSUPPORT;
1958
1959         sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern);
1960         if (!sk)
1961                 return -ENOMEM;
1962
1963         /* Allocate a kcm mux, shared between KCM sockets */
1964         mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL);
1965         if (!mux) {
1966                 sk_free(sk);
1967                 return -ENOMEM;
1968         }
1969
1970         spin_lock_init(&mux->lock);
1971         spin_lock_init(&mux->rx_lock);
1972         INIT_LIST_HEAD(&mux->kcm_socks);
1973         INIT_LIST_HEAD(&mux->kcm_rx_waiters);
1974         INIT_LIST_HEAD(&mux->kcm_tx_waiters);
1975
1976         INIT_LIST_HEAD(&mux->psocks);
1977         INIT_LIST_HEAD(&mux->psocks_ready);
1978         INIT_LIST_HEAD(&mux->psocks_avail);
1979
1980         mux->knet = knet;
1981
1982         /* Add new MUX to list */
1983         mutex_lock(&knet->mutex);
1984         list_add_rcu(&mux->kcm_mux_list, &knet->mux_list);
1985         knet->count++;
1986         mutex_unlock(&knet->mutex);
1987
1988         skb_queue_head_init(&mux->rx_hold_queue);
1989
1990         /* Init KCM socket */
1991         sock_init_data(sock, sk);
1992         init_kcm_sock(kcm_sk(sk), mux);
1993
1994         return 0;
1995 }
1996
1997 static struct net_proto_family kcm_family_ops = {
1998         .family = PF_KCM,
1999         .create = kcm_create,
2000         .owner  = THIS_MODULE,
2001 };
2002
2003 static __net_init int kcm_init_net(struct net *net)
2004 {
2005         struct kcm_net *knet = net_generic(net, kcm_net_id);
2006
2007         INIT_LIST_HEAD_RCU(&knet->mux_list);
2008         mutex_init(&knet->mutex);
2009
2010         return 0;
2011 }
2012
2013 static __net_exit void kcm_exit_net(struct net *net)
2014 {
2015         struct kcm_net *knet = net_generic(net, kcm_net_id);
2016
2017         /* All KCM sockets should be closed at this point, which should mean
2018          * that all multiplexors and psocks have been destroyed.
2019          */
2020         WARN_ON(!list_empty(&knet->mux_list));
2021 }
2022
2023 static struct pernet_operations kcm_net_ops = {
2024         .init = kcm_init_net,
2025         .exit = kcm_exit_net,
2026         .id   = &kcm_net_id,
2027         .size = sizeof(struct kcm_net),
2028 };
2029
2030 static int __init kcm_init(void)
2031 {
2032         int err = -ENOMEM;
2033
2034         kcm_muxp = kmem_cache_create("kcm_mux_cache",
2035                                      sizeof(struct kcm_mux), 0,
2036                                      SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
2037         if (!kcm_muxp)
2038                 goto fail;
2039
2040         kcm_psockp = kmem_cache_create("kcm_psock_cache",
2041                                        sizeof(struct kcm_psock), 0,
2042                                         SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
2043         if (!kcm_psockp)
2044                 goto fail;
2045
2046         kcm_wq = create_singlethread_workqueue("kkcmd");
2047         if (!kcm_wq)
2048                 goto fail;
2049
2050         err = proto_register(&kcm_proto, 1);
2051         if (err)
2052                 goto fail;
2053
2054         err = sock_register(&kcm_family_ops);
2055         if (err)
2056                 goto sock_register_fail;
2057
2058         err = register_pernet_device(&kcm_net_ops);
2059         if (err)
2060                 goto net_ops_fail;
2061
2062         err = kcm_proc_init();
2063         if (err)
2064                 goto proc_init_fail;
2065
2066         return 0;
2067
2068 proc_init_fail:
2069         unregister_pernet_device(&kcm_net_ops);
2070
2071 net_ops_fail:
2072         sock_unregister(PF_KCM);
2073
2074 sock_register_fail:
2075         proto_unregister(&kcm_proto);
2076
2077 fail:
2078         kmem_cache_destroy(kcm_muxp);
2079         kmem_cache_destroy(kcm_psockp);
2080
2081         if (kcm_wq)
2082                 destroy_workqueue(kcm_wq);
2083
2084         return err;
2085 }
2086
2087 static void __exit kcm_exit(void)
2088 {
2089         kcm_proc_exit();
2090         unregister_pernet_device(&kcm_net_ops);
2091         sock_unregister(PF_KCM);
2092         proto_unregister(&kcm_proto);
2093         destroy_workqueue(kcm_wq);
2094
2095         kmem_cache_destroy(kcm_muxp);
2096         kmem_cache_destroy(kcm_psockp);
2097 }
2098
2099 module_init(kcm_init);
2100 module_exit(kcm_exit);
2101
2102 MODULE_LICENSE("GPL");
2103 MODULE_ALIAS_NETPROTO(PF_KCM);
2104