net/vmw_vsock/virtio_transport_common.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * common code for virtio vsock
   4  *
   5  * Copyright (C) 2013-2015 Red Hat, Inc.
   6  * Author: Asias He <asias@redhat.com>
   7  *         Stefan Hajnoczi <stefanha@redhat.com>
   8  */
   9 #include <linux/spinlock.h>
  10 #include <linux/module.h>
  11 #include <linux/sched/signal.h>
  12 #include <linux/ctype.h>
  13 #include <linux/list.h>
  14 #include <linux/virtio_vsock.h>
  15 #include <uapi/linux/vsockmon.h>
  16
  17 #include <net/sock.h>
  18 #include <net/af_vsock.h>
  19
  20 #define CREATE_TRACE_POINTS
  21 #include <trace/events/vsock_virtio_transport_common.h>
  22
  23 /* How long to wait for graceful shutdown of a connection */
  24 #define VSOCK_CLOSE_TIMEOUT (8 * HZ)
  25
  26 /* Threshold for detecting small packets to copy */
  27 #define GOOD_COPY_LEN  128
  28
  29 static const struct virtio_transport *
  30 virtio_transport_get_ops(struct vsock_sock *vsk)
  31 {
  32         const struct vsock_transport *t = vsock_core_get_transport(vsk);
  33
  34         if (WARN_ON(!t))
  35                 return NULL;
  36
  37         return container_of(t, struct virtio_transport, transport);
  38 }
  39
  40 static bool virtio_transport_can_zcopy(const struct virtio_transport *t_ops,
  41                                        struct virtio_vsock_pkt_info *info,
  42                                        size_t pkt_len)
  43 {
  44         struct iov_iter *iov_iter;
  45
  46         if (!info->msg)
  47                 return false;
  48
  49         iov_iter = &info->msg->msg_iter;
  50
  51         if (iov_iter->iov_offset)
  52                 return false;
  53
  54         /* We can't send whole iov. */
  55         if (iov_iter->count > pkt_len)
  56                 return false;
  57
  58         /* Check that transport can send data in zerocopy mode. */
  59         t_ops = virtio_transport_get_ops(info->vsk);
  60
  61         if (t_ops->can_msgzerocopy) {
  62                 int pages_to_send = iov_iter_npages(iov_iter, MAX_SKB_FRAGS);
  63
  64                 /* +1 is for packet header. */
  65                 return t_ops->can_msgzerocopy(pages_to_send + 1);
  66         }
  67
  68         return true;
  69 }
  70
  71 static int virtio_transport_init_zcopy_skb(struct vsock_sock *vsk,
  72                                            struct sk_buff *skb,
  73                                            struct msghdr *msg,
  74                                            bool zerocopy)
  75 {
  76         struct ubuf_info *uarg;
  77
  78         if (msg->msg_ubuf) {
  79                 uarg = msg->msg_ubuf;
  80                 net_zcopy_get(uarg);
  81         } else {
  82                 struct iov_iter *iter = &msg->msg_iter;
  83                 struct ubuf_info_msgzc *uarg_zc;
  84
  85                 uarg = msg_zerocopy_realloc(sk_vsock(vsk),
  86                                             iter->count,
  87                                             NULL);
  88                 if (!uarg)
  89                         return -1;
  90
  91                 uarg_zc = uarg_to_msgzc(uarg);
  92                 uarg_zc->zerocopy = zerocopy ? 1 : 0;
  93         }
  94
  95         skb_zcopy_init(skb, uarg);
  96
  97         return 0;
  98 }
  99
 100 static int virtio_transport_fill_skb(struct sk_buff *skb,
 101                                      struct virtio_vsock_pkt_info *info,
 102                                      size_t len,
 103                                      bool zcopy)
 104 {
 105         if (zcopy)
 106                 return __zerocopy_sg_from_iter(info->msg, NULL, skb,
 107                                                &info->msg->msg_iter,
 108                                                len);
 109
 110         return memcpy_from_msg(skb_put(skb, len), info->msg, len);
 111 }
 112
 113 static void virtio_transport_init_hdr(struct sk_buff *skb,
 114                                       struct virtio_vsock_pkt_info *info,
 115                                       size_t payload_len,
 116                                       u32 src_cid,
 117                                       u32 src_port,
 118                                       u32 dst_cid,
 119                                       u32 dst_port)
 120 {
 121         struct virtio_vsock_hdr *hdr;
 122
 123         hdr = virtio_vsock_hdr(skb);
 124         hdr->type       = cpu_to_le16(info->type);
 125         hdr->op         = cpu_to_le16(info->op);
 126         hdr->src_cid    = cpu_to_le64(src_cid);
 127         hdr->dst_cid    = cpu_to_le64(dst_cid);
 128         hdr->src_port   = cpu_to_le32(src_port);
 129         hdr->dst_port   = cpu_to_le32(dst_port);
 130         hdr->flags      = cpu_to_le32(info->flags);
 131         hdr->len        = cpu_to_le32(payload_len);
 132         hdr->buf_alloc  = cpu_to_le32(0);
 133         hdr->fwd_cnt    = cpu_to_le32(0);
 134 }
 135
 136 static void virtio_transport_copy_nonlinear_skb(const struct sk_buff *skb,
 137                                                 void *dst,
 138                                                 size_t len)
 139 {
 140         struct iov_iter iov_iter = { 0 };
 141         struct kvec kvec;
 142         size_t to_copy;
 143
 144         kvec.iov_base = dst;
 145         kvec.iov_len = len;
 146
 147         iov_iter.iter_type = ITER_KVEC;
 148         iov_iter.kvec = &kvec;
 149         iov_iter.nr_segs = 1;
 150
 151         to_copy = min_t(size_t, len, skb->len);
 152
 153         skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
 154                                &iov_iter, to_copy);
 155 }
 156
 157 /* Packet capture */
 158 static struct sk_buff *virtio_transport_build_skb(void *opaque)
 159 {
 160         struct virtio_vsock_hdr *pkt_hdr;
 161         struct sk_buff *pkt = opaque;
 162         struct af_vsockmon_hdr *hdr;
 163         struct sk_buff *skb;
 164         size_t payload_len;
 165
 166         /* A packet could be split to fit the RX buffer, so we can retrieve
 167          * the payload length from the header and the buffer pointer taking
 168          * care of the offset in the original packet.
 169          */
 170         pkt_hdr = virtio_vsock_hdr(pkt);
 171         payload_len = pkt->len;
 172
 173         skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
 174                         GFP_ATOMIC);
 175         if (!skb)
 176                 return NULL;
 177
 178         hdr = skb_put(skb, sizeof(*hdr));
 179
 180         /* pkt->hdr is little-endian so no need to byteswap here */
 181         hdr->src_cid = pkt_hdr->src_cid;
 182         hdr->src_port = pkt_hdr->src_port;
 183         hdr->dst_cid = pkt_hdr->dst_cid;
 184         hdr->dst_port = pkt_hdr->dst_port;
 185
 186         hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
 187         hdr->len = cpu_to_le16(sizeof(*pkt_hdr));
 188         memset(hdr->reserved, 0, sizeof(hdr->reserved));
 189
 190         switch (le16_to_cpu(pkt_hdr->op)) {
 191         case VIRTIO_VSOCK_OP_REQUEST:
 192         case VIRTIO_VSOCK_OP_RESPONSE:
 193                 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
 194                 break;
 195         case VIRTIO_VSOCK_OP_RST:
 196         case VIRTIO_VSOCK_OP_SHUTDOWN:
 197                 hdr->op = cpu_to_le16(AF_VSOCK_OP_DISCONNECT);
 198                 break;
 199         case VIRTIO_VSOCK_OP_RW:
 200                 hdr->op = cpu_to_le16(AF_VSOCK_OP_PAYLOAD);
 201                 break;
 202         case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
 203         case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
 204                 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
 205                 break;
 206         default:
 207                 hdr->op = cpu_to_le16(AF_VSOCK_OP_UNKNOWN);
 208                 break;
 209         }
 210
 211         skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
 212
 213         if (payload_len) {
 214                 if (skb_is_nonlinear(pkt)) {
 215                         void *data = skb_put(skb, payload_len);
 216
 217                         virtio_transport_copy_nonlinear_skb(pkt, data, payload_len);
 218                 } else {
 219                         skb_put_data(skb, pkt->data, payload_len);
 220                 }
 221         }
 222
 223         return skb;
 224 }
 225
 226 void virtio_transport_deliver_tap_pkt(struct sk_buff *skb)
 227 {
 228         if (virtio_vsock_skb_tap_delivered(skb))
 229                 return;
 230
 231         vsock_deliver_tap(virtio_transport_build_skb, skb);
 232         virtio_vsock_skb_set_tap_delivered(skb);
 233 }
 234 EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
 235
 236 static u16 virtio_transport_get_type(struct sock *sk)
 237 {
 238         if (sk->sk_type == SOCK_STREAM)
 239                 return VIRTIO_VSOCK_TYPE_STREAM;
 240         else
 241                 return VIRTIO_VSOCK_TYPE_SEQPACKET;
 242 }
 243
 244 /* Returns new sk_buff on success, otherwise returns NULL. */
 245 static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
 246                                                   size_t payload_len,
 247                                                   bool zcopy,
 248                                                   u32 src_cid,
 249                                                   u32 src_port,
 250                                                   u32 dst_cid,
 251                                                   u32 dst_port)
 252 {
 253         struct vsock_sock *vsk;
 254         struct sk_buff *skb;
 255         size_t skb_len;
 256
 257         skb_len = VIRTIO_VSOCK_SKB_HEADROOM;
 258
 259         if (!zcopy)
 260                 skb_len += payload_len;
 261
 262         skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
 263         if (!skb)
 264                 return NULL;
 265
 266         virtio_transport_init_hdr(skb, info, payload_len, src_cid, src_port,
 267                                   dst_cid, dst_port);
 268
 269         vsk = info->vsk;
 270
 271         /* If 'vsk' != NULL then payload is always present, so we
 272          * will never call '__zerocopy_sg_from_iter()' below without
 273          * setting skb owner in 'skb_set_owner_w()'. The only case
 274          * when 'vsk' == NULL is VIRTIO_VSOCK_OP_RST control message
 275          * without payload.
 276          */
 277         WARN_ON_ONCE(!(vsk && (info->msg && payload_len)) && zcopy);
 278
 279         /* Set owner here, because '__zerocopy_sg_from_iter()' uses
 280          * owner of skb without check to update 'sk_wmem_alloc'.
 281          */
 282         if (vsk)
 283                 skb_set_owner_w(skb, sk_vsock(vsk));
 284
 285         if (info->msg && payload_len > 0) {
 286                 int err;
 287
 288                 err = virtio_transport_fill_skb(skb, info, payload_len, zcopy);
 289                 if (err)
 290                         goto out;
 291
 292                 if (msg_data_left(info->msg) == 0 &&
 293                     info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
 294                         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 295
 296                         hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
 297
 298                         if (info->msg->msg_flags & MSG_EOR)
 299                                 hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
 300                 }
 301         }
 302
 303         if (info->reply)
 304                 virtio_vsock_skb_set_reply(skb);
 305
 306         trace_virtio_transport_alloc_pkt(src_cid, src_port,
 307                                          dst_cid, dst_port,
 308                                          payload_len,
 309                                          info->type,
 310                                          info->op,
 311                                          info->flags,
 312                                          zcopy);
 313
 314         return skb;
 315 out:
 316         kfree_skb(skb);
 317         return NULL;
 318 }
 319
 320 /* This function can only be used on connecting/connected sockets,
 321  * since a socket assigned to a transport is required.
 322  *
 323  * Do not use on listener sockets!
 324  */
 325 static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 326                                           struct virtio_vsock_pkt_info *info)
 327 {
 328         u32 max_skb_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
 329         u32 src_cid, src_port, dst_cid, dst_port;
 330         const struct virtio_transport *t_ops;
 331         struct virtio_vsock_sock *vvs;
 332         u32 pkt_len = info->pkt_len;
 333         bool can_zcopy = false;
 334         u32 rest_len;
 335         int ret;
 336
 337         info->type = virtio_transport_get_type(sk_vsock(vsk));
 338
 339         t_ops = virtio_transport_get_ops(vsk);
 340         if (unlikely(!t_ops))
 341                 return -EFAULT;
 342
 343         src_cid = t_ops->transport.get_local_cid();
 344         src_port = vsk->local_addr.svm_port;
 345         if (!info->remote_cid) {
 346                 dst_cid = vsk->remote_addr.svm_cid;
 347                 dst_port = vsk->remote_addr.svm_port;
 348         } else {
 349                 dst_cid = info->remote_cid;
 350                 dst_port = info->remote_port;
 351         }
 352
 353         vvs = vsk->trans;
 354
 355         /* virtio_transport_get_credit might return less than pkt_len credit */
 356         pkt_len = virtio_transport_get_credit(vvs, pkt_len);
 357
 358         /* Do not send zero length OP_RW pkt */
 359         if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
 360                 return pkt_len;
 361
 362         if (info->msg) {
 363                 /* If zerocopy is not enabled by 'setsockopt()', we behave as
 364                  * there is no MSG_ZEROCOPY flag set.
 365                  */
 366                 if (!sock_flag(sk_vsock(vsk), SOCK_ZEROCOPY))
 367                         info->msg->msg_flags &= ~MSG_ZEROCOPY;
 368
 369                 if (info->msg->msg_flags & MSG_ZEROCOPY)
 370                         can_zcopy = virtio_transport_can_zcopy(t_ops, info, pkt_len);
 371
 372                 if (can_zcopy)
 373                         max_skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE,
 374                                             (MAX_SKB_FRAGS * PAGE_SIZE));
 375         }
 376
 377         rest_len = pkt_len;
 378
 379         do {
 380                 struct sk_buff *skb;
 381                 size_t skb_len;
 382
 383                 skb_len = min(max_skb_len, rest_len);
 384
 385                 skb = virtio_transport_alloc_skb(info, skb_len, can_zcopy,
 386                                                  src_cid, src_port,
 387                                                  dst_cid, dst_port);
 388                 if (!skb) {
 389                         ret = -ENOMEM;
 390                         break;
 391                 }
 392
 393                 /* We process buffer part by part, allocating skb on
 394                  * each iteration. If this is last skb for this buffer
 395                  * and MSG_ZEROCOPY mode is in use - we must allocate
 396                  * completion for the current syscall.
 397                  */
 398                 if (info->msg && info->msg->msg_flags & MSG_ZEROCOPY &&
 399                     skb_len == rest_len && info->op == VIRTIO_VSOCK_OP_RW) {
 400                         if (virtio_transport_init_zcopy_skb(vsk, skb,
 401                                                             info->msg,
 402                                                             can_zcopy)) {
 403                                 ret = -ENOMEM;
 404                                 break;
 405                         }
 406                 }
 407
 408                 virtio_transport_inc_tx_pkt(vvs, skb);
 409
 410                 ret = t_ops->send_pkt(skb);
 411                 if (ret < 0)
 412                         break;
 413
 414                 /* Both virtio and vhost 'send_pkt()' returns 'skb_len',
 415                  * but for reliability use 'ret' instead of 'skb_len'.
 416                  * Also if partial send happens (e.g. 'ret' != 'skb_len')
 417                  * somehow, we break this loop, but account such returned
 418                  * value in 'virtio_transport_put_credit()'.
 419                  */
 420                 rest_len -= ret;
 421
 422                 if (WARN_ONCE(ret != skb_len,
 423                               "'send_pkt()' returns %i, but %zu expected\n",
 424                               ret, skb_len))
 425                         break;
 426         } while (rest_len);
 427
 428         virtio_transport_put_credit(vvs, rest_len);
 429
 430         /* Return number of bytes, if any data has been sent. */
 431         if (rest_len != pkt_len)
 432                 ret = pkt_len - rest_len;
 433
 434         return ret;
 435 }
 436
 437 static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
 438                                         u32 len)
 439 {
 440         if (vvs->rx_bytes + len > vvs->buf_alloc)
 441                 return false;
 442
 443         vvs->rx_bytes += len;
 444         return true;
 445 }
 446
 447 static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
 448                                         u32 len)
 449 {
 450         vvs->rx_bytes -= len;
 451         vvs->fwd_cnt += len;
 452 }
 453
 454 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *skb)
 455 {
 456         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 457
 458         spin_lock_bh(&vvs->rx_lock);
 459         vvs->last_fwd_cnt = vvs->fwd_cnt;
 460         hdr->fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
 461         hdr->buf_alloc = cpu_to_le32(vvs->buf_alloc);
 462         spin_unlock_bh(&vvs->rx_lock);
 463 }
 464 EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
 465
 466 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
 467 {
 468         u32 ret;
 469
 470         if (!credit)
 471                 return 0;
 472
 473         spin_lock_bh(&vvs->tx_lock);
 474         ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
 475         if (ret > credit)
 476                 ret = credit;
 477         vvs->tx_cnt += ret;
 478         spin_unlock_bh(&vvs->tx_lock);
 479
 480         return ret;
 481 }
 482 EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
 483
 484 void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
 485 {
 486         if (!credit)
 487                 return;
 488
 489         spin_lock_bh(&vvs->tx_lock);
 490         vvs->tx_cnt -= credit;
 491         spin_unlock_bh(&vvs->tx_lock);
 492 }
 493 EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
 494
 495 static int virtio_transport_send_credit_update(struct vsock_sock *vsk)
 496 {
 497         struct virtio_vsock_pkt_info info = {
 498                 .op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
 499                 .vsk = vsk,
 500         };
 501
 502         return virtio_transport_send_pkt_info(vsk, &info);
 503 }
 504
 505 static ssize_t
 506 virtio_transport_stream_do_peek(struct vsock_sock *vsk,
 507                                 struct msghdr *msg,
 508                                 size_t len)
 509 {
 510         struct virtio_vsock_sock *vvs = vsk->trans;
 511         struct sk_buff *skb;
 512         size_t total = 0;
 513         int err;
 514
 515         spin_lock_bh(&vvs->rx_lock);
 516
 517         skb_queue_walk(&vvs->rx_queue, skb) {
 518                 size_t bytes;
 519
 520                 bytes = len - total;
 521                 if (bytes > skb->len)
 522                         bytes = skb->len;
 523
 524                 spin_unlock_bh(&vvs->rx_lock);
 525
 526                 /* sk_lock is held by caller so no one else can dequeue.
 527                  * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
 528                  */
 529                 err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
 530                                              &msg->msg_iter, bytes);
 531                 if (err)
 532                         goto out;
 533
 534                 total += bytes;
 535
 536                 spin_lock_bh(&vvs->rx_lock);
 537
 538                 if (total == len)
 539                         break;
 540         }
 541
 542         spin_unlock_bh(&vvs->rx_lock);
 543
 544         return total;
 545
 546 out:
 547         if (total)
 548                 err = total;
 549         return err;
 550 }
 551
 552 static ssize_t
 553 virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
 554                                    struct msghdr *msg,
 555                                    size_t len)
 556 {
 557         struct virtio_vsock_sock *vvs = vsk->trans;
 558         size_t bytes, total = 0;
 559         struct sk_buff *skb;
 560         u32 fwd_cnt_delta;
 561         bool low_rx_bytes;
 562         int err = -EFAULT;
 563         u32 free_space;
 564
 565         spin_lock_bh(&vvs->rx_lock);
 566
 567         if (WARN_ONCE(skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes,
 568                       "rx_queue is empty, but rx_bytes is non-zero\n")) {
 569                 spin_unlock_bh(&vvs->rx_lock);
 570                 return err;
 571         }
 572
 573         while (total < len && !skb_queue_empty(&vvs->rx_queue)) {
 574                 skb = skb_peek(&vvs->rx_queue);
 575
 576                 bytes = min_t(size_t, len - total,
 577                               skb->len - VIRTIO_VSOCK_SKB_CB(skb)->offset);
 578
 579                 /* sk_lock is held by caller so no one else can dequeue.
 580                  * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
 581                  */
 582                 spin_unlock_bh(&vvs->rx_lock);
 583
 584                 err = skb_copy_datagram_iter(skb,
 585                                              VIRTIO_VSOCK_SKB_CB(skb)->offset,
 586                                              &msg->msg_iter, bytes);
 587                 if (err)
 588                         goto out;
 589
 590                 spin_lock_bh(&vvs->rx_lock);
 591
 592                 total += bytes;
 593
 594                 VIRTIO_VSOCK_SKB_CB(skb)->offset += bytes;
 595
 596                 if (skb->len == VIRTIO_VSOCK_SKB_CB(skb)->offset) {
 597                         u32 pkt_len = le32_to_cpu(virtio_vsock_hdr(skb)->len);
 598
 599                         virtio_transport_dec_rx_pkt(vvs, pkt_len);
 600                         __skb_unlink(skb, &vvs->rx_queue);
 601                         consume_skb(skb);
 602                 }
 603         }
 604
 605         fwd_cnt_delta = vvs->fwd_cnt - vvs->last_fwd_cnt;
 606         free_space = vvs->buf_alloc - fwd_cnt_delta;
 607         low_rx_bytes = (vvs->rx_bytes <
 608                         sock_rcvlowat(sk_vsock(vsk), 0, INT_MAX));
 609
 610         spin_unlock_bh(&vvs->rx_lock);
 611
 612         /* To reduce the number of credit update messages,
 613          * don't update credits as long as lots of space is available.
 614          * Note: the limit chosen here is arbitrary. Setting the limit
 615          * too high causes extra messages. Too low causes transmitter
 616          * stalls. As stalls are in theory more expensive than extra
 617          * messages, we set the limit to a high value. TODO: experiment
 618          * with different values. Also send credit update message when
 619          * number of bytes in rx queue is not enough to wake up reader.
 620          */
 621         if (fwd_cnt_delta &&
 622             (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE || low_rx_bytes))
 623                 virtio_transport_send_credit_update(vsk);
 624
 625         return total;
 626
 627 out:
 628         if (total)
 629                 err = total;
 630         return err;
 631 }
 632
 633 static ssize_t
 634 virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
 635                                    struct msghdr *msg)
 636 {
 637         struct virtio_vsock_sock *vvs = vsk->trans;
 638         struct sk_buff *skb;
 639         size_t total, len;
 640
 641         spin_lock_bh(&vvs->rx_lock);
 642
 643         if (!vvs->msg_count) {
 644                 spin_unlock_bh(&vvs->rx_lock);
 645                 return 0;
 646         }
 647
 648         total = 0;
 649         len = msg_data_left(msg);
 650
 651         skb_queue_walk(&vvs->rx_queue, skb) {
 652                 struct virtio_vsock_hdr *hdr;
 653
 654                 if (total < len) {
 655                         size_t bytes;
 656                         int err;
 657
 658                         bytes = len - total;
 659                         if (bytes > skb->len)
 660                                 bytes = skb->len;
 661
 662                         spin_unlock_bh(&vvs->rx_lock);
 663
 664                         /* sk_lock is held by caller so no one else can dequeue.
 665                          * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
 666                          */
 667                         err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset,
 668                                                      &msg->msg_iter, bytes);
 669                         if (err)
 670                                 return err;
 671
 672                         spin_lock_bh(&vvs->rx_lock);
 673                 }
 674
 675                 total += skb->len;
 676                 hdr = virtio_vsock_hdr(skb);
 677
 678                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
 679                         if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
 680                                 msg->msg_flags |= MSG_EOR;
 681
 682                         break;
 683                 }
 684         }
 685
 686         spin_unlock_bh(&vvs->rx_lock);
 687
 688         return total;
 689 }
 690
 691 static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
 692                                                  struct msghdr *msg,
 693                                                  int flags)
 694 {
 695         struct virtio_vsock_sock *vvs = vsk->trans;
 696         int dequeued_len = 0;
 697         size_t user_buf_len = msg_data_left(msg);
 698         bool msg_ready = false;
 699         struct sk_buff *skb;
 700
 701         spin_lock_bh(&vvs->rx_lock);
 702
 703         if (vvs->msg_count == 0) {
 704                 spin_unlock_bh(&vvs->rx_lock);
 705                 return 0;
 706         }
 707
 708         while (!msg_ready) {
 709                 struct virtio_vsock_hdr *hdr;
 710                 size_t pkt_len;
 711
 712                 skb = __skb_dequeue(&vvs->rx_queue);
 713                 if (!skb)
 714                         break;
 715                 hdr = virtio_vsock_hdr(skb);
 716                 pkt_len = (size_t)le32_to_cpu(hdr->len);
 717
 718                 if (dequeued_len >= 0) {
 719                         size_t bytes_to_copy;
 720
 721                         bytes_to_copy = min(user_buf_len, pkt_len);
 722
 723                         if (bytes_to_copy) {
 724                                 int err;
 725
 726                                 /* sk_lock is held by caller so no one else can dequeue.
 727                                  * Unlock rx_lock since skb_copy_datagram_iter() may sleep.
 728                                  */
 729                                 spin_unlock_bh(&vvs->rx_lock);
 730
 731                                 err = skb_copy_datagram_iter(skb, 0,
 732                                                              &msg->msg_iter,
 733                                                              bytes_to_copy);
 734                                 if (err) {
 735                                         /* Copy of message failed. Rest of
 736                                          * fragments will be freed without copy.
 737                                          */
 738                                         dequeued_len = err;
 739                                 } else {
 740                                         user_buf_len -= bytes_to_copy;
 741                                 }
 742
 743                                 spin_lock_bh(&vvs->rx_lock);
 744                         }
 745
 746                         if (dequeued_len >= 0)
 747                                 dequeued_len += pkt_len;
 748                 }
 749
 750                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
 751                         msg_ready = true;
 752                         vvs->msg_count--;
 753
 754                         if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
 755                                 msg->msg_flags |= MSG_EOR;
 756                 }
 757
 758                 virtio_transport_dec_rx_pkt(vvs, pkt_len);
 759                 kfree_skb(skb);
 760         }
 761
 762         spin_unlock_bh(&vvs->rx_lock);
 763
 764         virtio_transport_send_credit_update(vsk);
 765
 766         return dequeued_len;
 767 }
 768
 769 ssize_t
 770 virtio_transport_stream_dequeue(struct vsock_sock *vsk,
 771                                 struct msghdr *msg,
 772                                 size_t len, int flags)
 773 {
 774         if (flags & MSG_PEEK)
 775                 return virtio_transport_stream_do_peek(vsk, msg, len);
 776         else
 777                 return virtio_transport_stream_do_dequeue(vsk, msg, len);
 778 }
 779 EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
 780
 781 ssize_t
 782 virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
 783                                    struct msghdr *msg,
 784                                    int flags)
 785 {
 786         if (flags & MSG_PEEK)
 787                 return virtio_transport_seqpacket_do_peek(vsk, msg);
 788         else
 789                 return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
 790 }
 791 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
 792
 793 int
 794 virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
 795                                    struct msghdr *msg,
 796                                    size_t len)
 797 {
 798         struct virtio_vsock_sock *vvs = vsk->trans;
 799
 800         spin_lock_bh(&vvs->tx_lock);
 801
 802         if (len > vvs->peer_buf_alloc) {
 803                 spin_unlock_bh(&vvs->tx_lock);
 804                 return -EMSGSIZE;
 805         }
 806
 807         spin_unlock_bh(&vvs->tx_lock);
 808
 809         return virtio_transport_stream_enqueue(vsk, msg, len);
 810 }
 811 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
 812
 813 int
 814 virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
 815                                struct msghdr *msg,
 816                                size_t len, int flags)
 817 {
 818         return -EOPNOTSUPP;
 819 }
 820 EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
 821
 822 s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
 823 {
 824         struct virtio_vsock_sock *vvs = vsk->trans;
 825         s64 bytes;
 826
 827         spin_lock_bh(&vvs->rx_lock);
 828         bytes = vvs->rx_bytes;
 829         spin_unlock_bh(&vvs->rx_lock);
 830
 831         return bytes;
 832 }
 833 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
 834
 835 u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk)
 836 {
 837         struct virtio_vsock_sock *vvs = vsk->trans;
 838         u32 msg_count;
 839
 840         spin_lock_bh(&vvs->rx_lock);
 841         msg_count = vvs->msg_count;
 842         spin_unlock_bh(&vvs->rx_lock);
 843
 844         return msg_count;
 845 }
 846 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_has_data);
 847
 848 static s64 virtio_transport_has_space(struct vsock_sock *vsk)
 849 {
 850         struct virtio_vsock_sock *vvs = vsk->trans;
 851         s64 bytes;
 852
 853         bytes = (s64)vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
 854         if (bytes < 0)
 855                 bytes = 0;
 856
 857         return bytes;
 858 }
 859
 860 s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
 861 {
 862         struct virtio_vsock_sock *vvs = vsk->trans;
 863         s64 bytes;
 864
 865         spin_lock_bh(&vvs->tx_lock);
 866         bytes = virtio_transport_has_space(vsk);
 867         spin_unlock_bh(&vvs->tx_lock);
 868
 869         return bytes;
 870 }
 871 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
 872
 873 int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 874                                     struct vsock_sock *psk)
 875 {
 876         struct virtio_vsock_sock *vvs;
 877
 878         vvs = kzalloc(sizeof(*vvs), GFP_KERNEL);
 879         if (!vvs)
 880                 return -ENOMEM;
 881
 882         vsk->trans = vvs;
 883         vvs->vsk = vsk;
 884         if (psk && psk->trans) {
 885                 struct virtio_vsock_sock *ptrans = psk->trans;
 886
 887                 vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
 888         }
 889
 890         if (vsk->buffer_size > VIRTIO_VSOCK_MAX_BUF_SIZE)
 891                 vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
 892
 893         vvs->buf_alloc = vsk->buffer_size;
 894
 895         spin_lock_init(&vvs->rx_lock);
 896         spin_lock_init(&vvs->tx_lock);
 897         skb_queue_head_init(&vvs->rx_queue);
 898
 899         return 0;
 900 }
 901 EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
 902
 903 /* sk_lock held by the caller */
 904 void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
 905 {
 906         struct virtio_vsock_sock *vvs = vsk->trans;
 907
 908         if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
 909                 *val = VIRTIO_VSOCK_MAX_BUF_SIZE;
 910
 911         vvs->buf_alloc = *val;
 912
 913         virtio_transport_send_credit_update(vsk);
 914 }
 915 EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
 916
 917 int
 918 virtio_transport_notify_poll_in(struct vsock_sock *vsk,
 919                                 size_t target,
 920                                 bool *data_ready_now)
 921 {
 922         *data_ready_now = vsock_stream_has_data(vsk) >= target;
 923
 924         return 0;
 925 }
 926 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
 927
 928 int
 929 virtio_transport_notify_poll_out(struct vsock_sock *vsk,
 930                                  size_t target,
 931                                  bool *space_avail_now)
 932 {
 933         s64 free_space;
 934
 935         free_space = vsock_stream_has_space(vsk);
 936         if (free_space > 0)
 937                 *space_avail_now = true;
 938         else if (free_space == 0)
 939                 *space_avail_now = false;
 940
 941         return 0;
 942 }
 943 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
 944
 945 int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
 946         size_t target, struct vsock_transport_recv_notify_data *data)
 947 {
 948         return 0;
 949 }
 950 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
 951
 952 int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
 953         size_t target, struct vsock_transport_recv_notify_data *data)
 954 {
 955         return 0;
 956 }
 957 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
 958
 959 int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
 960         size_t target, struct vsock_transport_recv_notify_data *data)
 961 {
 962         return 0;
 963 }
 964 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
 965
 966 int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
 967         size_t target, ssize_t copied, bool data_read,
 968         struct vsock_transport_recv_notify_data *data)
 969 {
 970         return 0;
 971 }
 972 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
 973
 974 int virtio_transport_notify_send_init(struct vsock_sock *vsk,
 975         struct vsock_transport_send_notify_data *data)
 976 {
 977         return 0;
 978 }
 979 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
 980
 981 int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
 982         struct vsock_transport_send_notify_data *data)
 983 {
 984         return 0;
 985 }
 986 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
 987
 988 int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
 989         struct vsock_transport_send_notify_data *data)
 990 {
 991         return 0;
 992 }
 993 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
 994
 995 int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
 996         ssize_t written, struct vsock_transport_send_notify_data *data)
 997 {
 998         return 0;
 999 }
1000 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
1001
1002 u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
1003 {
1004         return vsk->buffer_size;
1005 }
1006 EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
1007
1008 bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
1009 {
1010         return true;
1011 }
1012 EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
1013
1014 bool virtio_transport_stream_allow(u32 cid, u32 port)
1015 {
1016         return true;
1017 }
1018 EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
1019
1020 int virtio_transport_dgram_bind(struct vsock_sock *vsk,
1021                                 struct sockaddr_vm *addr)
1022 {
1023         return -EOPNOTSUPP;
1024 }
1025 EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
1026
1027 bool virtio_transport_dgram_allow(u32 cid, u32 port)
1028 {
1029         return false;
1030 }
1031 EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
1032
1033 int virtio_transport_connect(struct vsock_sock *vsk)
1034 {
1035         struct virtio_vsock_pkt_info info = {
1036                 .op = VIRTIO_VSOCK_OP_REQUEST,
1037                 .vsk = vsk,
1038         };
1039
1040         return virtio_transport_send_pkt_info(vsk, &info);
1041 }
1042 EXPORT_SYMBOL_GPL(virtio_transport_connect);
1043
1044 int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
1045 {
1046         struct virtio_vsock_pkt_info info = {
1047                 .op = VIRTIO_VSOCK_OP_SHUTDOWN,
1048                 .flags = (mode & RCV_SHUTDOWN ?
1049                           VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
1050                          (mode & SEND_SHUTDOWN ?
1051                           VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
1052                 .vsk = vsk,
1053         };
1054
1055         return virtio_transport_send_pkt_info(vsk, &info);
1056 }
1057 EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
1058
1059 int
1060 virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
1061                                struct sockaddr_vm *remote_addr,
1062                                struct msghdr *msg,
1063                                size_t dgram_len)
1064 {
1065         return -EOPNOTSUPP;
1066 }
1067 EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
1068
1069 ssize_t
1070 virtio_transport_stream_enqueue(struct vsock_sock *vsk,
1071                                 struct msghdr *msg,
1072                                 size_t len)
1073 {
1074         struct virtio_vsock_pkt_info info = {
1075                 .op = VIRTIO_VSOCK_OP_RW,
1076                 .msg = msg,
1077                 .pkt_len = len,
1078                 .vsk = vsk,
1079         };
1080
1081         return virtio_transport_send_pkt_info(vsk, &info);
1082 }
1083 EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
1084
1085 void virtio_transport_destruct(struct vsock_sock *vsk)
1086 {
1087         struct virtio_vsock_sock *vvs = vsk->trans;
1088
1089         kfree(vvs);
1090 }
1091 EXPORT_SYMBOL_GPL(virtio_transport_destruct);
1092
1093 static int virtio_transport_reset(struct vsock_sock *vsk,
1094                                   struct sk_buff *skb)
1095 {
1096         struct virtio_vsock_pkt_info info = {
1097                 .op = VIRTIO_VSOCK_OP_RST,
1098                 .reply = !!skb,
1099                 .vsk = vsk,
1100         };
1101
1102         /* Send RST only if the original pkt is not a RST pkt */
1103         if (skb && le16_to_cpu(virtio_vsock_hdr(skb)->op) == VIRTIO_VSOCK_OP_RST)
1104                 return 0;
1105
1106         return virtio_transport_send_pkt_info(vsk, &info);
1107 }
1108
1109 /* Normally packets are associated with a socket.  There may be no socket if an
1110  * attempt was made to connect to a socket that does not exist.
1111  */
1112 static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
1113                                           struct sk_buff *skb)
1114 {
1115         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1116         struct virtio_vsock_pkt_info info = {
1117                 .op = VIRTIO_VSOCK_OP_RST,
1118                 .type = le16_to_cpu(hdr->type),
1119                 .reply = true,
1120         };
1121         struct sk_buff *reply;
1122
1123         /* Send RST only if the original pkt is not a RST pkt */
1124         if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
1125                 return 0;
1126
1127         if (!t)
1128                 return -ENOTCONN;
1129
1130         reply = virtio_transport_alloc_skb(&info, 0, false,
1131                                            le64_to_cpu(hdr->dst_cid),
1132                                            le32_to_cpu(hdr->dst_port),
1133                                            le64_to_cpu(hdr->src_cid),
1134                                            le32_to_cpu(hdr->src_port));
1135         if (!reply)
1136                 return -ENOMEM;
1137
1138         return t->send_pkt(reply);
1139 }
1140
1141 /* This function should be called with sk_lock held and SOCK_DONE set */
1142 static void virtio_transport_remove_sock(struct vsock_sock *vsk)
1143 {
1144         struct virtio_vsock_sock *vvs = vsk->trans;
1145
1146         /* We don't need to take rx_lock, as the socket is closing and we are
1147          * removing it.
1148          */
1149         __skb_queue_purge(&vvs->rx_queue);
1150         vsock_remove_sock(vsk);
1151 }
1152
1153 static void virtio_transport_wait_close(struct sock *sk, long timeout)
1154 {
1155         if (timeout) {
1156                 DEFINE_WAIT_FUNC(wait, woken_wake_function);
1157
1158                 add_wait_queue(sk_sleep(sk), &wait);
1159
1160                 do {
1161                         if (sk_wait_event(sk, &timeout,
1162                                           sock_flag(sk, SOCK_DONE), &wait))
1163                                 break;
1164                 } while (!signal_pending(current) && timeout);
1165
1166                 remove_wait_queue(sk_sleep(sk), &wait);
1167         }
1168 }
1169
1170 static void virtio_transport_do_close(struct vsock_sock *vsk,
1171                                       bool cancel_timeout)
1172 {
1173         struct sock *sk = sk_vsock(vsk);
1174
1175         sock_set_flag(sk, SOCK_DONE);
1176         vsk->peer_shutdown = SHUTDOWN_MASK;
1177         if (vsock_stream_has_data(vsk) <= 0)
1178                 sk->sk_state = TCP_CLOSING;
1179         sk->sk_state_change(sk);
1180
1181         if (vsk->close_work_scheduled &&
1182             (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
1183                 vsk->close_work_scheduled = false;
1184
1185                 virtio_transport_remove_sock(vsk);
1186
1187                 /* Release refcnt obtained when we scheduled the timeout */
1188                 sock_put(sk);
1189         }
1190 }
1191
1192 static void virtio_transport_close_timeout(struct work_struct *work)
1193 {
1194         struct vsock_sock *vsk =
1195                 container_of(work, struct vsock_sock, close_work.work);
1196         struct sock *sk = sk_vsock(vsk);
1197
1198         sock_hold(sk);
1199         lock_sock(sk);
1200
1201         if (!sock_flag(sk, SOCK_DONE)) {
1202                 (void)virtio_transport_reset(vsk, NULL);
1203
1204                 virtio_transport_do_close(vsk, false);
1205         }
1206
1207         vsk->close_work_scheduled = false;
1208
1209         release_sock(sk);
1210         sock_put(sk);
1211 }
1212
1213 /* User context, vsk->sk is locked */
1214 static bool virtio_transport_close(struct vsock_sock *vsk)
1215 {
1216         struct sock *sk = &vsk->sk;
1217
1218         if (!(sk->sk_state == TCP_ESTABLISHED ||
1219               sk->sk_state == TCP_CLOSING))
1220                 return true;
1221
1222         /* Already received SHUTDOWN from peer, reply with RST */
1223         if ((vsk->peer_shutdown & SHUTDOWN_MASK) == SHUTDOWN_MASK) {
1224                 (void)virtio_transport_reset(vsk, NULL);
1225                 return true;
1226         }
1227
1228         if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK)
1229                 (void)virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
1230
1231         if (sock_flag(sk, SOCK_LINGER) && !(current->flags & PF_EXITING))
1232                 virtio_transport_wait_close(sk, sk->sk_lingertime);
1233
1234         if (sock_flag(sk, SOCK_DONE)) {
1235                 return true;
1236         }
1237
1238         sock_hold(sk);
1239         INIT_DELAYED_WORK(&vsk->close_work,
1240                           virtio_transport_close_timeout);
1241         vsk->close_work_scheduled = true;
1242         schedule_delayed_work(&vsk->close_work, VSOCK_CLOSE_TIMEOUT);
1243         return false;
1244 }
1245
1246 void virtio_transport_release(struct vsock_sock *vsk)
1247 {
1248         struct sock *sk = &vsk->sk;
1249         bool remove_sock = true;
1250
1251         if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
1252                 remove_sock = virtio_transport_close(vsk);
1253
1254         if (remove_sock) {
1255                 sock_set_flag(sk, SOCK_DONE);
1256                 virtio_transport_remove_sock(vsk);
1257         }
1258 }
1259 EXPORT_SYMBOL_GPL(virtio_transport_release);
1260
1261 static int
1262 virtio_transport_recv_connecting(struct sock *sk,
1263                                  struct sk_buff *skb)
1264 {
1265         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1266         struct vsock_sock *vsk = vsock_sk(sk);
1267         int skerr;
1268         int err;
1269
1270         switch (le16_to_cpu(hdr->op)) {
1271         case VIRTIO_VSOCK_OP_RESPONSE:
1272                 sk->sk_state = TCP_ESTABLISHED;
1273                 sk->sk_socket->state = SS_CONNECTED;
1274                 vsock_insert_connected(vsk);
1275                 sk->sk_state_change(sk);
1276                 break;
1277         case VIRTIO_VSOCK_OP_INVALID:
1278                 break;
1279         case VIRTIO_VSOCK_OP_RST:
1280                 skerr = ECONNRESET;
1281                 err = 0;
1282                 goto destroy;
1283         default:
1284                 skerr = EPROTO;
1285                 err = -EINVAL;
1286                 goto destroy;
1287         }
1288         return 0;
1289
1290 destroy:
1291         virtio_transport_reset(vsk, skb);
1292         sk->sk_state = TCP_CLOSE;
1293         sk->sk_err = skerr;
1294         sk_error_report(sk);
1295         return err;
1296 }
1297
1298 static void
1299 virtio_transport_recv_enqueue(struct vsock_sock *vsk,
1300                               struct sk_buff *skb)
1301 {
1302         struct virtio_vsock_sock *vvs = vsk->trans;
1303         bool can_enqueue, free_pkt = false;
1304         struct virtio_vsock_hdr *hdr;
1305         u32 len;
1306
1307         hdr = virtio_vsock_hdr(skb);
1308         len = le32_to_cpu(hdr->len);
1309
1310         spin_lock_bh(&vvs->rx_lock);
1311
1312         can_enqueue = virtio_transport_inc_rx_pkt(vvs, len);
1313         if (!can_enqueue) {
1314                 free_pkt = true;
1315                 goto out;
1316         }
1317
1318         if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)
1319                 vvs->msg_count++;
1320
1321         /* Try to copy small packets into the buffer of last packet queued,
1322          * to avoid wasting memory queueing the entire buffer with a small
1323          * payload.
1324          */
1325         if (len <= GOOD_COPY_LEN && !skb_queue_empty(&vvs->rx_queue)) {
1326                 struct virtio_vsock_hdr *last_hdr;
1327                 struct sk_buff *last_skb;
1328
1329                 last_skb = skb_peek_tail(&vvs->rx_queue);
1330                 last_hdr = virtio_vsock_hdr(last_skb);
1331
1332                 /* If there is space in the last packet queued, we copy the
1333                  * new packet in its buffer. We avoid this if the last packet
1334                  * queued has VIRTIO_VSOCK_SEQ_EOM set, because this is
1335                  * delimiter of SEQPACKET message, so 'pkt' is the first packet
1336                  * of a new message.
1337                  */
1338                 if (skb->len < skb_tailroom(last_skb) &&
1339                     !(le32_to_cpu(last_hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)) {
1340                         memcpy(skb_put(last_skb, skb->len), skb->data, skb->len);
1341                         free_pkt = true;
1342                         last_hdr->flags |= hdr->flags;
1343                         le32_add_cpu(&last_hdr->len, len);
1344                         goto out;
1345                 }
1346         }
1347
1348         __skb_queue_tail(&vvs->rx_queue, skb);
1349
1350 out:
1351         spin_unlock_bh(&vvs->rx_lock);
1352         if (free_pkt)
1353                 kfree_skb(skb);
1354 }
1355
1356 static int
1357 virtio_transport_recv_connected(struct sock *sk,
1358                                 struct sk_buff *skb)
1359 {
1360         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1361         struct vsock_sock *vsk = vsock_sk(sk);
1362         int err = 0;
1363
1364         switch (le16_to_cpu(hdr->op)) {
1365         case VIRTIO_VSOCK_OP_RW:
1366                 virtio_transport_recv_enqueue(vsk, skb);
1367                 vsock_data_ready(sk);
1368                 return err;
1369         case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
1370                 virtio_transport_send_credit_update(vsk);
1371                 break;
1372         case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
1373                 sk->sk_write_space(sk);
1374                 break;
1375         case VIRTIO_VSOCK_OP_SHUTDOWN:
1376                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
1377                         vsk->peer_shutdown |= RCV_SHUTDOWN;
1378                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
1379                         vsk->peer_shutdown |= SEND_SHUTDOWN;
1380                 if (vsk->peer_shutdown == SHUTDOWN_MASK) {
1381                         if (vsock_stream_has_data(vsk) <= 0 && !sock_flag(sk, SOCK_DONE)) {
1382                                 (void)virtio_transport_reset(vsk, NULL);
1383                                 virtio_transport_do_close(vsk, true);
1384                         }
1385                         /* Remove this socket anyway because the remote peer sent
1386                          * the shutdown. This way a new connection will succeed
1387                          * if the remote peer uses the same source port,
1388                          * even if the old socket is still unreleased, but now disconnected.
1389                          */
1390                         vsock_remove_sock(vsk);
1391                 }
1392                 if (le32_to_cpu(virtio_vsock_hdr(skb)->flags))
1393                         sk->sk_state_change(sk);
1394                 break;
1395         case VIRTIO_VSOCK_OP_RST:
1396                 virtio_transport_do_close(vsk, true);
1397                 break;
1398         default:
1399                 err = -EINVAL;
1400                 break;
1401         }
1402
1403         kfree_skb(skb);
1404         return err;
1405 }
1406
1407 static void
1408 virtio_transport_recv_disconnecting(struct sock *sk,
1409                                     struct sk_buff *skb)
1410 {
1411         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1412         struct vsock_sock *vsk = vsock_sk(sk);
1413
1414         if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
1415                 virtio_transport_do_close(vsk, true);
1416 }
1417
1418 static int
1419 virtio_transport_send_response(struct vsock_sock *vsk,
1420                                struct sk_buff *skb)
1421 {
1422         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1423         struct virtio_vsock_pkt_info info = {
1424                 .op = VIRTIO_VSOCK_OP_RESPONSE,
1425                 .remote_cid = le64_to_cpu(hdr->src_cid),
1426                 .remote_port = le32_to_cpu(hdr->src_port),
1427                 .reply = true,
1428                 .vsk = vsk,
1429         };
1430
1431         return virtio_transport_send_pkt_info(vsk, &info);
1432 }
1433
1434 static bool virtio_transport_space_update(struct sock *sk,
1435                                           struct sk_buff *skb)
1436 {
1437         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1438         struct vsock_sock *vsk = vsock_sk(sk);
1439         struct virtio_vsock_sock *vvs = vsk->trans;
1440         bool space_available;
1441
1442         /* Listener sockets are not associated with any transport, so we are
1443          * not able to take the state to see if there is space available in the
1444          * remote peer, but since they are only used to receive requests, we
1445          * can assume that there is always space available in the other peer.
1446          */
1447         if (!vvs)
1448                 return true;
1449
1450         /* buf_alloc and fwd_cnt is always included in the hdr */
1451         spin_lock_bh(&vvs->tx_lock);
1452         vvs->peer_buf_alloc = le32_to_cpu(hdr->buf_alloc);
1453         vvs->peer_fwd_cnt = le32_to_cpu(hdr->fwd_cnt);
1454         space_available = virtio_transport_has_space(vsk);
1455         spin_unlock_bh(&vvs->tx_lock);
1456         return space_available;
1457 }
1458
1459 /* Handle server socket */
1460 static int
1461 virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
1462                              struct virtio_transport *t)
1463 {
1464         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1465         struct vsock_sock *vsk = vsock_sk(sk);
1466         struct vsock_sock *vchild;
1467         struct sock *child;
1468         int ret;
1469
1470         if (le16_to_cpu(hdr->op) != VIRTIO_VSOCK_OP_REQUEST) {
1471                 virtio_transport_reset_no_sock(t, skb);
1472                 return -EINVAL;
1473         }
1474
1475         if (sk_acceptq_is_full(sk)) {
1476                 virtio_transport_reset_no_sock(t, skb);
1477                 return -ENOMEM;
1478         }
1479
1480         child = vsock_create_connected(sk);
1481         if (!child) {
1482                 virtio_transport_reset_no_sock(t, skb);
1483                 return -ENOMEM;
1484         }
1485
1486         sk_acceptq_added(sk);
1487
1488         lock_sock_nested(child, SINGLE_DEPTH_NESTING);
1489
1490         child->sk_state = TCP_ESTABLISHED;
1491
1492         vchild = vsock_sk(child);
1493         vsock_addr_init(&vchild->local_addr, le64_to_cpu(hdr->dst_cid),
1494                         le32_to_cpu(hdr->dst_port));
1495         vsock_addr_init(&vchild->remote_addr, le64_to_cpu(hdr->src_cid),
1496                         le32_to_cpu(hdr->src_port));
1497
1498         ret = vsock_assign_transport(vchild, vsk);
1499         /* Transport assigned (looking at remote_addr) must be the same
1500          * where we received the request.
1501          */
1502         if (ret || vchild->transport != &t->transport) {
1503                 release_sock(child);
1504                 virtio_transport_reset_no_sock(t, skb);
1505                 sock_put(child);
1506                 return ret;
1507         }
1508
1509         if (virtio_transport_space_update(child, skb))
1510                 child->sk_write_space(child);
1511
1512         vsock_insert_connected(vchild);
1513         vsock_enqueue_accept(sk, child);
1514         virtio_transport_send_response(vchild, skb);
1515
1516         release_sock(child);
1517
1518         sk->sk_data_ready(sk);
1519         return 0;
1520 }
1521
1522 static bool virtio_transport_valid_type(u16 type)
1523 {
1524         return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
1525                (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
1526 }
1527
1528 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
1529  * lock.
1530  */
1531 void virtio_transport_recv_pkt(struct virtio_transport *t,
1532                                struct sk_buff *skb)
1533 {
1534         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1535         struct sockaddr_vm src, dst;
1536         struct vsock_sock *vsk;
1537         struct sock *sk;
1538         bool space_available;
1539
1540         vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
1541                         le32_to_cpu(hdr->src_port));
1542         vsock_addr_init(&dst, le64_to_cpu(hdr->dst_cid),
1543                         le32_to_cpu(hdr->dst_port));
1544
1545         trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
1546                                         dst.svm_cid, dst.svm_port,
1547                                         le32_to_cpu(hdr->len),
1548                                         le16_to_cpu(hdr->type),
1549                                         le16_to_cpu(hdr->op),
1550                                         le32_to_cpu(hdr->flags),
1551                                         le32_to_cpu(hdr->buf_alloc),
1552                                         le32_to_cpu(hdr->fwd_cnt));
1553
1554         if (!virtio_transport_valid_type(le16_to_cpu(hdr->type))) {
1555                 (void)virtio_transport_reset_no_sock(t, skb);
1556                 goto free_pkt;
1557         }
1558
1559         /* The socket must be in connected or bound table
1560          * otherwise send reset back
1561          */
1562         sk = vsock_find_connected_socket(&src, &dst);
1563         if (!sk) {
1564                 sk = vsock_find_bound_socket(&dst);
1565                 if (!sk) {
1566                         (void)virtio_transport_reset_no_sock(t, skb);
1567                         goto free_pkt;
1568                 }
1569         }
1570
1571         if (virtio_transport_get_type(sk) != le16_to_cpu(hdr->type)) {
1572                 (void)virtio_transport_reset_no_sock(t, skb);
1573                 sock_put(sk);
1574                 goto free_pkt;
1575         }
1576
1577         if (!skb_set_owner_sk_safe(skb, sk)) {
1578                 WARN_ONCE(1, "receiving vsock socket has sk_refcnt == 0\n");
1579                 goto free_pkt;
1580         }
1581
1582         vsk = vsock_sk(sk);
1583
1584         lock_sock(sk);
1585
1586         /* Check if sk has been closed before lock_sock */
1587         if (sock_flag(sk, SOCK_DONE)) {
1588                 (void)virtio_transport_reset_no_sock(t, skb);
1589                 release_sock(sk);
1590                 sock_put(sk);
1591                 goto free_pkt;
1592         }
1593
1594         space_available = virtio_transport_space_update(sk, skb);
1595
1596         /* Update CID in case it has changed after a transport reset event */
1597         if (vsk->local_addr.svm_cid != VMADDR_CID_ANY)
1598                 vsk->local_addr.svm_cid = dst.svm_cid;
1599
1600         if (space_available)
1601                 sk->sk_write_space(sk);
1602
1603         switch (sk->sk_state) {
1604         case TCP_LISTEN:
1605                 virtio_transport_recv_listen(sk, skb, t);
1606                 kfree_skb(skb);
1607                 break;
1608         case TCP_SYN_SENT:
1609                 virtio_transport_recv_connecting(sk, skb);
1610                 kfree_skb(skb);
1611                 break;
1612         case TCP_ESTABLISHED:
1613                 virtio_transport_recv_connected(sk, skb);
1614                 break;
1615         case TCP_CLOSING:
1616                 virtio_transport_recv_disconnecting(sk, skb);
1617                 kfree_skb(skb);
1618                 break;
1619         default:
1620                 (void)virtio_transport_reset_no_sock(t, skb);
1621                 kfree_skb(skb);
1622                 break;
1623         }
1624
1625         release_sock(sk);
1626
1627         /* Release refcnt obtained when we fetched this socket out of the
1628          * bound or connected list.
1629          */
1630         sock_put(sk);
1631         return;
1632
1633 free_pkt:
1634         kfree_skb(skb);
1635 }
1636 EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
1637
1638 /* Remove skbs found in a queue that have a vsk that matches.
1639  *
1640  * Each skb is freed.
1641  *
1642  * Returns the count of skbs that were reply packets.
1643  */
1644 int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
1645 {
1646         struct sk_buff_head freeme;
1647         struct sk_buff *skb, *tmp;
1648         int cnt = 0;
1649
1650         skb_queue_head_init(&freeme);
1651
1652         spin_lock_bh(&queue->lock);
1653         skb_queue_walk_safe(queue, skb, tmp) {
1654                 if (vsock_sk(skb->sk) != vsk)
1655                         continue;
1656
1657                 __skb_unlink(skb, queue);
1658                 __skb_queue_tail(&freeme, skb);
1659
1660                 if (virtio_vsock_skb_reply(skb))
1661                         cnt++;
1662         }
1663         spin_unlock_bh(&queue->lock);
1664
1665         __skb_queue_purge(&freeme);
1666
1667         return cnt;
1668 }
1669 EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
1670
1671 int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_actor)
1672 {
1673         struct virtio_vsock_sock *vvs = vsk->trans;
1674         struct sock *sk = sk_vsock(vsk);
1675         struct sk_buff *skb;
1676         int off = 0;
1677         int err;
1678
1679         spin_lock_bh(&vvs->rx_lock);
1680         /* Use __skb_recv_datagram() for race-free handling of the receive. It
1681          * works for types other than dgrams.
1682          */
1683         skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);
1684         spin_unlock_bh(&vvs->rx_lock);
1685
1686         if (!skb)
1687                 return err;
1688
1689         return recv_actor(sk, skb);
1690 }
1691 EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
1692
1693 int virtio_transport_notify_set_rcvlowat(struct vsock_sock *vsk, int val)
1694 {
1695         struct virtio_vsock_sock *vvs = vsk->trans;
1696         bool send_update;
1697
1698         spin_lock_bh(&vvs->rx_lock);
1699
1700         /* If number of available bytes is less than new SO_RCVLOWAT value,
1701          * kick sender to send more data, because sender may sleep in its
1702          * 'send()' syscall waiting for enough space at our side. Also
1703          * don't send credit update when peer already knows actual value -
1704          * such transmission will be useless.
1705          */
1706         send_update = (vvs->rx_bytes < val) &&
1707                       (vvs->fwd_cnt != vvs->last_fwd_cnt);
1708
1709         spin_unlock_bh(&vvs->rx_lock);
1710
1711         if (send_update) {
1712                 int err;
1713
1714                 err = virtio_transport_send_credit_update(vsk);
1715                 if (err < 0)
1716                         return err;
1717         }
1718
1719         return 0;
1720 }
1721 EXPORT_SYMBOL_GPL(virtio_transport_notify_set_rcvlowat);
1722
1723 MODULE_LICENSE("GPL v2");
1724 MODULE_AUTHOR("Asias He");
1725 MODULE_DESCRIPTION("common code for virtio vsock");