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 <[email protected]>
   7  *         Stefan Hajnoczi <[email protected]>
   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 /* Returns a new packet on success, otherwise returns NULL.
  41  *
  42  * If NULL is returned, errp is set to a negative errno.
  43  */
  44 static struct sk_buff *
  45 virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
  46                            size_t len,
  47                            u32 src_cid,
  48                            u32 src_port,
  49                            u32 dst_cid,
  50                            u32 dst_port)
  51 {
  52         const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
  53         struct virtio_vsock_hdr *hdr;
  54         struct sk_buff *skb;
  55         void *payload;
  56         int err;
  57
  58         skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
  59         if (!skb)
  60                 return NULL;
  61
  62         hdr = virtio_vsock_hdr(skb);
  63         hdr->type       = cpu_to_le16(info->type);
  64         hdr->op         = cpu_to_le16(info->op);
  65         hdr->src_cid    = cpu_to_le64(src_cid);
  66         hdr->dst_cid    = cpu_to_le64(dst_cid);
  67         hdr->src_port   = cpu_to_le32(src_port);
  68         hdr->dst_port   = cpu_to_le32(dst_port);
  69         hdr->flags      = cpu_to_le32(info->flags);
  70         hdr->len        = cpu_to_le32(len);
  71
  72         if (info->msg && len > 0) {
  73                 payload = skb_put(skb, len);
  74                 err = memcpy_from_msg(payload, info->msg, len);
  75                 if (err)
  76                         goto out;
  77
  78                 if (msg_data_left(info->msg) == 0 &&
  79                     info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
  80                         hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
  81
  82                         if (info->msg->msg_flags & MSG_EOR)
  83                                 hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
  84                 }
  85         }
  86
  87         if (info->reply)
  88                 virtio_vsock_skb_set_reply(skb);
  89
  90         trace_virtio_transport_alloc_pkt(src_cid, src_port,
  91                                          dst_cid, dst_port,
  92                                          len,
  93                                          info->type,
  94                                          info->op,
  95                                          info->flags);
  96
  97         return skb;
  98
  99 out:
 100         kfree_skb(skb);
 101         return NULL;
 102 }
 103
 104 /* Packet capture */
 105 static struct sk_buff *virtio_transport_build_skb(void *opaque)
 106 {
 107         struct virtio_vsock_hdr *pkt_hdr;
 108         struct sk_buff *pkt = opaque;
 109         struct af_vsockmon_hdr *hdr;
 110         struct sk_buff *skb;
 111         size_t payload_len;
 112         void *payload_buf;
 113
 114         /* A packet could be split to fit the RX buffer, so we can retrieve
 115          * the payload length from the header and the buffer pointer taking
 116          * care of the offset in the original packet.
 117          */
 118         pkt_hdr = virtio_vsock_hdr(pkt);
 119         payload_len = pkt->len;
 120         payload_buf = pkt->data;
 121
 122         skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
 123                         GFP_ATOMIC);
 124         if (!skb)
 125                 return NULL;
 126
 127         hdr = skb_put(skb, sizeof(*hdr));
 128
 129         /* pkt->hdr is little-endian so no need to byteswap here */
 130         hdr->src_cid = pkt_hdr->src_cid;
 131         hdr->src_port = pkt_hdr->src_port;
 132         hdr->dst_cid = pkt_hdr->dst_cid;
 133         hdr->dst_port = pkt_hdr->dst_port;
 134
 135         hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
 136         hdr->len = cpu_to_le16(sizeof(*pkt_hdr));
 137         memset(hdr->reserved, 0, sizeof(hdr->reserved));
 138
 139         switch (le16_to_cpu(pkt_hdr->op)) {
 140         case VIRTIO_VSOCK_OP_REQUEST:
 141         case VIRTIO_VSOCK_OP_RESPONSE:
 142                 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
 143                 break;
 144         case VIRTIO_VSOCK_OP_RST:
 145         case VIRTIO_VSOCK_OP_SHUTDOWN:
 146                 hdr->op = cpu_to_le16(AF_VSOCK_OP_DISCONNECT);
 147                 break;
 148         case VIRTIO_VSOCK_OP_RW:
 149                 hdr->op = cpu_to_le16(AF_VSOCK_OP_PAYLOAD);
 150                 break;
 151         case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
 152         case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
 153                 hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
 154                 break;
 155         default:
 156                 hdr->op = cpu_to_le16(AF_VSOCK_OP_UNKNOWN);
 157                 break;
 158         }
 159
 160         skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
 161
 162         if (payload_len) {
 163                 skb_put_data(skb, payload_buf, payload_len);
 164         }
 165
 166         return skb;
 167 }
 168
 169 void virtio_transport_deliver_tap_pkt(struct sk_buff *skb)
 170 {
 171         if (virtio_vsock_skb_tap_delivered(skb))
 172                 return;
 173
 174         vsock_deliver_tap(virtio_transport_build_skb, skb);
 175         virtio_vsock_skb_set_tap_delivered(skb);
 176 }
 177 EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
 178
 179 static u16 virtio_transport_get_type(struct sock *sk)
 180 {
 181         if (sk->sk_type == SOCK_STREAM)
 182                 return VIRTIO_VSOCK_TYPE_STREAM;
 183         else
 184                 return VIRTIO_VSOCK_TYPE_SEQPACKET;
 185 }
 186
 187 /* This function can only be used on connecting/connected sockets,
 188  * since a socket assigned to a transport is required.
 189  *
 190  * Do not use on listener sockets!
 191  */
 192 static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 193                                           struct virtio_vsock_pkt_info *info)
 194 {
 195         u32 src_cid, src_port, dst_cid, dst_port;
 196         const struct virtio_transport *t_ops;
 197         struct virtio_vsock_sock *vvs;
 198         u32 pkt_len = info->pkt_len;
 199         struct sk_buff *skb;
 200
 201         info->type = virtio_transport_get_type(sk_vsock(vsk));
 202
 203         t_ops = virtio_transport_get_ops(vsk);
 204         if (unlikely(!t_ops))
 205                 return -EFAULT;
 206
 207         src_cid = t_ops->transport.get_local_cid();
 208         src_port = vsk->local_addr.svm_port;
 209         if (!info->remote_cid) {
 210                 dst_cid = vsk->remote_addr.svm_cid;
 211                 dst_port = vsk->remote_addr.svm_port;
 212         } else {
 213                 dst_cid = info->remote_cid;
 214                 dst_port = info->remote_port;
 215         }
 216
 217         vvs = vsk->trans;
 218
 219         /* we can send less than pkt_len bytes */
 220         if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
 221                 pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
 222
 223         /* virtio_transport_get_credit might return less than pkt_len credit */
 224         pkt_len = virtio_transport_get_credit(vvs, pkt_len);
 225
 226         /* Do not send zero length OP_RW pkt */
 227         if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
 228                 return pkt_len;
 229
 230         skb = virtio_transport_alloc_skb(info, pkt_len,
 231                                          src_cid, src_port,
 232                                          dst_cid, dst_port);
 233         if (!skb) {
 234                 virtio_transport_put_credit(vvs, pkt_len);
 235                 return -ENOMEM;
 236         }
 237
 238         virtio_transport_inc_tx_pkt(vvs, skb);
 239
 240         return t_ops->send_pkt(skb);
 241 }
 242
 243 static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
 244                                         struct sk_buff *skb)
 245 {
 246         if (vvs->rx_bytes + skb->len > vvs->buf_alloc)
 247                 return false;
 248
 249         vvs->rx_bytes += skb->len;
 250         return true;
 251 }
 252
 253 static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
 254                                         struct sk_buff *skb)
 255 {
 256         int len;
 257
 258         len = skb_headroom(skb) - sizeof(struct virtio_vsock_hdr) - skb->len;
 259         vvs->rx_bytes -= len;
 260         vvs->fwd_cnt += len;
 261 }
 262
 263 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *skb)
 264 {
 265         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 266
 267         spin_lock_bh(&vvs->rx_lock);
 268         vvs->last_fwd_cnt = vvs->fwd_cnt;
 269         hdr->fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
 270         hdr->buf_alloc = cpu_to_le32(vvs->buf_alloc);
 271         spin_unlock_bh(&vvs->rx_lock);
 272 }
 273 EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
 274
 275 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
 276 {
 277         u32 ret;
 278
 279         spin_lock_bh(&vvs->tx_lock);
 280         ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
 281         if (ret > credit)
 282                 ret = credit;
 283         vvs->tx_cnt += ret;
 284         spin_unlock_bh(&vvs->tx_lock);
 285
 286         return ret;
 287 }
 288 EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
 289
 290 void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
 291 {
 292         spin_lock_bh(&vvs->tx_lock);
 293         vvs->tx_cnt -= credit;
 294         spin_unlock_bh(&vvs->tx_lock);
 295 }
 296 EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
 297
 298 static int virtio_transport_send_credit_update(struct vsock_sock *vsk)
 299 {
 300         struct virtio_vsock_pkt_info info = {
 301                 .op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
 302                 .vsk = vsk,
 303         };
 304
 305         return virtio_transport_send_pkt_info(vsk, &info);
 306 }
 307
 308 static ssize_t
 309 virtio_transport_stream_do_peek(struct vsock_sock *vsk,
 310                                 struct msghdr *msg,
 311                                 size_t len)
 312 {
 313         struct virtio_vsock_sock *vvs = vsk->trans;
 314         size_t bytes, total = 0, off;
 315         struct sk_buff *skb, *tmp;
 316         int err = -EFAULT;
 317
 318         spin_lock_bh(&vvs->rx_lock);
 319
 320         skb_queue_walk_safe(&vvs->rx_queue, skb,  tmp) {
 321                 off = 0;
 322
 323                 if (total == len)
 324                         break;
 325
 326                 while (total < len && off < skb->len) {
 327                         bytes = len - total;
 328                         if (bytes > skb->len - off)
 329                                 bytes = skb->len - off;
 330
 331                         /* sk_lock is held by caller so no one else can dequeue.
 332                          * Unlock rx_lock since memcpy_to_msg() may sleep.
 333                          */
 334                         spin_unlock_bh(&vvs->rx_lock);
 335
 336                         err = memcpy_to_msg(msg, skb->data + off, bytes);
 337                         if (err)
 338                                 goto out;
 339
 340                         spin_lock_bh(&vvs->rx_lock);
 341
 342                         total += bytes;
 343                         off += bytes;
 344                 }
 345         }
 346
 347         spin_unlock_bh(&vvs->rx_lock);
 348
 349         return total;
 350
 351 out:
 352         if (total)
 353                 err = total;
 354         return err;
 355 }
 356
 357 static ssize_t
 358 virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
 359                                    struct msghdr *msg,
 360                                    size_t len)
 361 {
 362         struct virtio_vsock_sock *vvs = vsk->trans;
 363         size_t bytes, total = 0;
 364         struct sk_buff *skb;
 365         int err = -EFAULT;
 366         u32 free_space;
 367
 368         spin_lock_bh(&vvs->rx_lock);
 369         while (total < len && !skb_queue_empty(&vvs->rx_queue)) {
 370                 skb = __skb_dequeue(&vvs->rx_queue);
 371
 372                 bytes = len - total;
 373                 if (bytes > skb->len)
 374                         bytes = skb->len;
 375
 376                 /* sk_lock is held by caller so no one else can dequeue.
 377                  * Unlock rx_lock since memcpy_to_msg() may sleep.
 378                  */
 379                 spin_unlock_bh(&vvs->rx_lock);
 380
 381                 err = memcpy_to_msg(msg, skb->data, bytes);
 382                 if (err)
 383                         goto out;
 384
 385                 spin_lock_bh(&vvs->rx_lock);
 386
 387                 total += bytes;
 388                 skb_pull(skb, bytes);
 389
 390                 if (skb->len == 0) {
 391                         virtio_transport_dec_rx_pkt(vvs, skb);
 392                         consume_skb(skb);
 393                 } else {
 394                         __skb_queue_head(&vvs->rx_queue, skb);
 395                 }
 396         }
 397
 398         free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
 399
 400         spin_unlock_bh(&vvs->rx_lock);
 401
 402         /* To reduce the number of credit update messages,
 403          * don't update credits as long as lots of space is available.
 404          * Note: the limit chosen here is arbitrary. Setting the limit
 405          * too high causes extra messages. Too low causes transmitter
 406          * stalls. As stalls are in theory more expensive than extra
 407          * messages, we set the limit to a high value. TODO: experiment
 408          * with different values.
 409          */
 410         if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
 411                 virtio_transport_send_credit_update(vsk);
 412
 413         return total;
 414
 415 out:
 416         if (total)
 417                 err = total;
 418         return err;
 419 }
 420
 421 static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
 422                                                  struct msghdr *msg,
 423                                                  int flags)
 424 {
 425         struct virtio_vsock_sock *vvs = vsk->trans;
 426         int dequeued_len = 0;
 427         size_t user_buf_len = msg_data_left(msg);
 428         bool msg_ready = false;
 429         struct sk_buff *skb;
 430
 431         spin_lock_bh(&vvs->rx_lock);
 432
 433         if (vvs->msg_count == 0) {
 434                 spin_unlock_bh(&vvs->rx_lock);
 435                 return 0;
 436         }
 437
 438         while (!msg_ready) {
 439                 struct virtio_vsock_hdr *hdr;
 440
 441                 skb = __skb_dequeue(&vvs->rx_queue);
 442                 if (!skb)
 443                         break;
 444                 hdr = virtio_vsock_hdr(skb);
 445
 446                 if (dequeued_len >= 0) {
 447                         size_t pkt_len;
 448                         size_t bytes_to_copy;
 449
 450                         pkt_len = (size_t)le32_to_cpu(hdr->len);
 451                         bytes_to_copy = min(user_buf_len, pkt_len);
 452
 453                         if (bytes_to_copy) {
 454                                 int err;
 455
 456                                 /* sk_lock is held by caller so no one else can dequeue.
 457                                  * Unlock rx_lock since memcpy_to_msg() may sleep.
 458                                  */
 459                                 spin_unlock_bh(&vvs->rx_lock);
 460
 461                                 err = memcpy_to_msg(msg, skb->data, bytes_to_copy);
 462                                 if (err) {
 463                                         /* Copy of message failed. Rest of
 464                                          * fragments will be freed without copy.
 465                                          */
 466                                         dequeued_len = err;
 467                                 } else {
 468                                         user_buf_len -= bytes_to_copy;
 469                                         skb_pull(skb, bytes_to_copy);
 470                                 }
 471
 472                                 spin_lock_bh(&vvs->rx_lock);
 473                         }
 474
 475                         if (dequeued_len >= 0)
 476                                 dequeued_len += pkt_len;
 477                 }
 478
 479                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
 480                         msg_ready = true;
 481                         vvs->msg_count--;
 482
 483                         if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
 484                                 msg->msg_flags |= MSG_EOR;
 485                 }
 486
 487                 virtio_transport_dec_rx_pkt(vvs, skb);
 488                 kfree_skb(skb);
 489         }
 490
 491         spin_unlock_bh(&vvs->rx_lock);
 492
 493         virtio_transport_send_credit_update(vsk);
 494
 495         return dequeued_len;
 496 }
 497
 498 ssize_t
 499 virtio_transport_stream_dequeue(struct vsock_sock *vsk,
 500                                 struct msghdr *msg,
 501                                 size_t len, int flags)
 502 {
 503         if (flags & MSG_PEEK)
 504                 return virtio_transport_stream_do_peek(vsk, msg, len);
 505         else
 506                 return virtio_transport_stream_do_dequeue(vsk, msg, len);
 507 }
 508 EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
 509
 510 ssize_t
 511 virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
 512                                    struct msghdr *msg,
 513                                    int flags)
 514 {
 515         if (flags & MSG_PEEK)
 516                 return -EOPNOTSUPP;
 517
 518         return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
 519 }
 520 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
 521
 522 int
 523 virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
 524                                    struct msghdr *msg,
 525                                    size_t len)
 526 {
 527         struct virtio_vsock_sock *vvs = vsk->trans;
 528
 529         spin_lock_bh(&vvs->tx_lock);
 530
 531         if (len > vvs->peer_buf_alloc) {
 532                 spin_unlock_bh(&vvs->tx_lock);
 533                 return -EMSGSIZE;
 534         }
 535
 536         spin_unlock_bh(&vvs->tx_lock);
 537
 538         return virtio_transport_stream_enqueue(vsk, msg, len);
 539 }
 540 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
 541
 542 int
 543 virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
 544                                struct msghdr *msg,
 545                                size_t len, int flags)
 546 {
 547         return -EOPNOTSUPP;
 548 }
 549 EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
 550
 551 s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
 552 {
 553         struct virtio_vsock_sock *vvs = vsk->trans;
 554         s64 bytes;
 555
 556         spin_lock_bh(&vvs->rx_lock);
 557         bytes = vvs->rx_bytes;
 558         spin_unlock_bh(&vvs->rx_lock);
 559
 560         return bytes;
 561 }
 562 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
 563
 564 u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk)
 565 {
 566         struct virtio_vsock_sock *vvs = vsk->trans;
 567         u32 msg_count;
 568
 569         spin_lock_bh(&vvs->rx_lock);
 570         msg_count = vvs->msg_count;
 571         spin_unlock_bh(&vvs->rx_lock);
 572
 573         return msg_count;
 574 }
 575 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_has_data);
 576
 577 static s64 virtio_transport_has_space(struct vsock_sock *vsk)
 578 {
 579         struct virtio_vsock_sock *vvs = vsk->trans;
 580         s64 bytes;
 581
 582         bytes = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
 583         if (bytes < 0)
 584                 bytes = 0;
 585
 586         return bytes;
 587 }
 588
 589 s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
 590 {
 591         struct virtio_vsock_sock *vvs = vsk->trans;
 592         s64 bytes;
 593
 594         spin_lock_bh(&vvs->tx_lock);
 595         bytes = virtio_transport_has_space(vsk);
 596         spin_unlock_bh(&vvs->tx_lock);
 597
 598         return bytes;
 599 }
 600 EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
 601
 602 int virtio_transport_do_socket_init(struct vsock_sock *vsk,
 603                                     struct vsock_sock *psk)
 604 {
 605         struct virtio_vsock_sock *vvs;
 606
 607         vvs = kzalloc(sizeof(*vvs), GFP_KERNEL);
 608         if (!vvs)
 609                 return -ENOMEM;
 610
 611         vsk->trans = vvs;
 612         vvs->vsk = vsk;
 613         if (psk && psk->trans) {
 614                 struct virtio_vsock_sock *ptrans = psk->trans;
 615
 616                 vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
 617         }
 618
 619         if (vsk->buffer_size > VIRTIO_VSOCK_MAX_BUF_SIZE)
 620                 vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
 621
 622         vvs->buf_alloc = vsk->buffer_size;
 623
 624         spin_lock_init(&vvs->rx_lock);
 625         spin_lock_init(&vvs->tx_lock);
 626         skb_queue_head_init(&vvs->rx_queue);
 627
 628         return 0;
 629 }
 630 EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
 631
 632 /* sk_lock held by the caller */
 633 void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
 634 {
 635         struct virtio_vsock_sock *vvs = vsk->trans;
 636
 637         if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
 638                 *val = VIRTIO_VSOCK_MAX_BUF_SIZE;
 639
 640         vvs->buf_alloc = *val;
 641
 642         virtio_transport_send_credit_update(vsk);
 643 }
 644 EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
 645
 646 int
 647 virtio_transport_notify_poll_in(struct vsock_sock *vsk,
 648                                 size_t target,
 649                                 bool *data_ready_now)
 650 {
 651         *data_ready_now = vsock_stream_has_data(vsk) >= target;
 652
 653         return 0;
 654 }
 655 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
 656
 657 int
 658 virtio_transport_notify_poll_out(struct vsock_sock *vsk,
 659                                  size_t target,
 660                                  bool *space_avail_now)
 661 {
 662         s64 free_space;
 663
 664         free_space = vsock_stream_has_space(vsk);
 665         if (free_space > 0)
 666                 *space_avail_now = true;
 667         else if (free_space == 0)
 668                 *space_avail_now = false;
 669
 670         return 0;
 671 }
 672 EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
 673
 674 int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
 675         size_t target, struct vsock_transport_recv_notify_data *data)
 676 {
 677         return 0;
 678 }
 679 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
 680
 681 int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
 682         size_t target, struct vsock_transport_recv_notify_data *data)
 683 {
 684         return 0;
 685 }
 686 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
 687
 688 int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
 689         size_t target, struct vsock_transport_recv_notify_data *data)
 690 {
 691         return 0;
 692 }
 693 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
 694
 695 int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
 696         size_t target, ssize_t copied, bool data_read,
 697         struct vsock_transport_recv_notify_data *data)
 698 {
 699         return 0;
 700 }
 701 EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
 702
 703 int virtio_transport_notify_send_init(struct vsock_sock *vsk,
 704         struct vsock_transport_send_notify_data *data)
 705 {
 706         return 0;
 707 }
 708 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
 709
 710 int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
 711         struct vsock_transport_send_notify_data *data)
 712 {
 713         return 0;
 714 }
 715 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
 716
 717 int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
 718         struct vsock_transport_send_notify_data *data)
 719 {
 720         return 0;
 721 }
 722 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
 723
 724 int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
 725         ssize_t written, struct vsock_transport_send_notify_data *data)
 726 {
 727         return 0;
 728 }
 729 EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
 730
 731 u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
 732 {
 733         return vsk->buffer_size;
 734 }
 735 EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
 736
 737 bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
 738 {
 739         return true;
 740 }
 741 EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
 742
 743 bool virtio_transport_stream_allow(u32 cid, u32 port)
 744 {
 745         return true;
 746 }
 747 EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
 748
 749 int virtio_transport_dgram_bind(struct vsock_sock *vsk,
 750                                 struct sockaddr_vm *addr)
 751 {
 752         return -EOPNOTSUPP;
 753 }
 754 EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
 755
 756 bool virtio_transport_dgram_allow(u32 cid, u32 port)
 757 {
 758         return false;
 759 }
 760 EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
 761
 762 int virtio_transport_connect(struct vsock_sock *vsk)
 763 {
 764         struct virtio_vsock_pkt_info info = {
 765                 .op = VIRTIO_VSOCK_OP_REQUEST,
 766                 .vsk = vsk,
 767         };
 768
 769         return virtio_transport_send_pkt_info(vsk, &info);
 770 }
 771 EXPORT_SYMBOL_GPL(virtio_transport_connect);
 772
 773 int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
 774 {
 775         struct virtio_vsock_pkt_info info = {
 776                 .op = VIRTIO_VSOCK_OP_SHUTDOWN,
 777                 .flags = (mode & RCV_SHUTDOWN ?
 778                           VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
 779                          (mode & SEND_SHUTDOWN ?
 780                           VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
 781                 .vsk = vsk,
 782         };
 783
 784         return virtio_transport_send_pkt_info(vsk, &info);
 785 }
 786 EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
 787
 788 int
 789 virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
 790                                struct sockaddr_vm *remote_addr,
 791                                struct msghdr *msg,
 792                                size_t dgram_len)
 793 {
 794         return -EOPNOTSUPP;
 795 }
 796 EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
 797
 798 ssize_t
 799 virtio_transport_stream_enqueue(struct vsock_sock *vsk,
 800                                 struct msghdr *msg,
 801                                 size_t len)
 802 {
 803         struct virtio_vsock_pkt_info info = {
 804                 .op = VIRTIO_VSOCK_OP_RW,
 805                 .msg = msg,
 806                 .pkt_len = len,
 807                 .vsk = vsk,
 808         };
 809
 810         return virtio_transport_send_pkt_info(vsk, &info);
 811 }
 812 EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
 813
 814 void virtio_transport_destruct(struct vsock_sock *vsk)
 815 {
 816         struct virtio_vsock_sock *vvs = vsk->trans;
 817
 818         kfree(vvs);
 819 }
 820 EXPORT_SYMBOL_GPL(virtio_transport_destruct);
 821
 822 static int virtio_transport_reset(struct vsock_sock *vsk,
 823                                   struct sk_buff *skb)
 824 {
 825         struct virtio_vsock_pkt_info info = {
 826                 .op = VIRTIO_VSOCK_OP_RST,
 827                 .reply = !!skb,
 828                 .vsk = vsk,
 829         };
 830
 831         /* Send RST only if the original pkt is not a RST pkt */
 832         if (skb && le16_to_cpu(virtio_vsock_hdr(skb)->op) == VIRTIO_VSOCK_OP_RST)
 833                 return 0;
 834
 835         return virtio_transport_send_pkt_info(vsk, &info);
 836 }
 837
 838 /* Normally packets are associated with a socket.  There may be no socket if an
 839  * attempt was made to connect to a socket that does not exist.
 840  */
 841 static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
 842                                           struct sk_buff *skb)
 843 {
 844         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 845         struct virtio_vsock_pkt_info info = {
 846                 .op = VIRTIO_VSOCK_OP_RST,
 847                 .type = le16_to_cpu(hdr->type),
 848                 .reply = true,
 849         };
 850         struct sk_buff *reply;
 851
 852         /* Send RST only if the original pkt is not a RST pkt */
 853         if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
 854                 return 0;
 855
 856         reply = virtio_transport_alloc_skb(&info, 0,
 857                                            le64_to_cpu(hdr->dst_cid),
 858                                            le32_to_cpu(hdr->dst_port),
 859                                            le64_to_cpu(hdr->src_cid),
 860                                            le32_to_cpu(hdr->src_port));
 861         if (!reply)
 862                 return -ENOMEM;
 863
 864         if (!t) {
 865                 kfree_skb(reply);
 866                 return -ENOTCONN;
 867         }
 868
 869         return t->send_pkt(reply);
 870 }
 871
 872 /* This function should be called with sk_lock held and SOCK_DONE set */
 873 static void virtio_transport_remove_sock(struct vsock_sock *vsk)
 874 {
 875         struct virtio_vsock_sock *vvs = vsk->trans;
 876
 877         /* We don't need to take rx_lock, as the socket is closing and we are
 878          * removing it.
 879          */
 880         __skb_queue_purge(&vvs->rx_queue);
 881         vsock_remove_sock(vsk);
 882 }
 883
 884 static void virtio_transport_wait_close(struct sock *sk, long timeout)
 885 {
 886         if (timeout) {
 887                 DEFINE_WAIT_FUNC(wait, woken_wake_function);
 888
 889                 add_wait_queue(sk_sleep(sk), &wait);
 890
 891                 do {
 892                         if (sk_wait_event(sk, &timeout,
 893                                           sock_flag(sk, SOCK_DONE), &wait))
 894                                 break;
 895                 } while (!signal_pending(current) && timeout);
 896
 897                 remove_wait_queue(sk_sleep(sk), &wait);
 898         }
 899 }
 900
 901 static void virtio_transport_do_close(struct vsock_sock *vsk,
 902                                       bool cancel_timeout)
 903 {
 904         struct sock *sk = sk_vsock(vsk);
 905
 906         sock_set_flag(sk, SOCK_DONE);
 907         vsk->peer_shutdown = SHUTDOWN_MASK;
 908         if (vsock_stream_has_data(vsk) <= 0)
 909                 sk->sk_state = TCP_CLOSING;
 910         sk->sk_state_change(sk);
 911
 912         if (vsk->close_work_scheduled &&
 913             (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
 914                 vsk->close_work_scheduled = false;
 915
 916                 virtio_transport_remove_sock(vsk);
 917
 918                 /* Release refcnt obtained when we scheduled the timeout */
 919                 sock_put(sk);
 920         }
 921 }
 922
 923 static void virtio_transport_close_timeout(struct work_struct *work)
 924 {
 925         struct vsock_sock *vsk =
 926                 container_of(work, struct vsock_sock, close_work.work);
 927         struct sock *sk = sk_vsock(vsk);
 928
 929         sock_hold(sk);
 930         lock_sock(sk);
 931
 932         if (!sock_flag(sk, SOCK_DONE)) {
 933                 (void)virtio_transport_reset(vsk, NULL);
 934
 935                 virtio_transport_do_close(vsk, false);
 936         }
 937
 938         vsk->close_work_scheduled = false;
 939
 940         release_sock(sk);
 941         sock_put(sk);
 942 }
 943
 944 /* User context, vsk->sk is locked */
 945 static bool virtio_transport_close(struct vsock_sock *vsk)
 946 {
 947         struct sock *sk = &vsk->sk;
 948
 949         if (!(sk->sk_state == TCP_ESTABLISHED ||
 950               sk->sk_state == TCP_CLOSING))
 951                 return true;
 952
 953         /* Already received SHUTDOWN from peer, reply with RST */
 954         if ((vsk->peer_shutdown & SHUTDOWN_MASK) == SHUTDOWN_MASK) {
 955                 (void)virtio_transport_reset(vsk, NULL);
 956                 return true;
 957         }
 958
 959         if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK)
 960                 (void)virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
 961
 962         if (sock_flag(sk, SOCK_LINGER) && !(current->flags & PF_EXITING))
 963                 virtio_transport_wait_close(sk, sk->sk_lingertime);
 964
 965         if (sock_flag(sk, SOCK_DONE)) {
 966                 return true;
 967         }
 968
 969         sock_hold(sk);
 970         INIT_DELAYED_WORK(&vsk->close_work,
 971                           virtio_transport_close_timeout);
 972         vsk->close_work_scheduled = true;
 973         schedule_delayed_work(&vsk->close_work, VSOCK_CLOSE_TIMEOUT);
 974         return false;
 975 }
 976
 977 void virtio_transport_release(struct vsock_sock *vsk)
 978 {
 979         struct sock *sk = &vsk->sk;
 980         bool remove_sock = true;
 981
 982         if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
 983                 remove_sock = virtio_transport_close(vsk);
 984
 985         if (remove_sock) {
 986                 sock_set_flag(sk, SOCK_DONE);
 987                 virtio_transport_remove_sock(vsk);
 988         }
 989 }
 990 EXPORT_SYMBOL_GPL(virtio_transport_release);
 991
 992 static int
 993 virtio_transport_recv_connecting(struct sock *sk,
 994                                  struct sk_buff *skb)
 995 {
 996         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
 997         struct vsock_sock *vsk = vsock_sk(sk);
 998         int skerr;
 999         int err;
1000
1001         switch (le16_to_cpu(hdr->op)) {
1002         case VIRTIO_VSOCK_OP_RESPONSE:
1003                 sk->sk_state = TCP_ESTABLISHED;
1004                 sk->sk_socket->state = SS_CONNECTED;
1005                 vsock_insert_connected(vsk);
1006                 sk->sk_state_change(sk);
1007                 break;
1008         case VIRTIO_VSOCK_OP_INVALID:
1009                 break;
1010         case VIRTIO_VSOCK_OP_RST:
1011                 skerr = ECONNRESET;
1012                 err = 0;
1013                 goto destroy;
1014         default:
1015                 skerr = EPROTO;
1016                 err = -EINVAL;
1017                 goto destroy;
1018         }
1019         return 0;
1020
1021 destroy:
1022         virtio_transport_reset(vsk, skb);
1023         sk->sk_state = TCP_CLOSE;
1024         sk->sk_err = skerr;
1025         sk_error_report(sk);
1026         return err;
1027 }
1028
1029 static void
1030 virtio_transport_recv_enqueue(struct vsock_sock *vsk,
1031                               struct sk_buff *skb)
1032 {
1033         struct virtio_vsock_sock *vvs = vsk->trans;
1034         bool can_enqueue, free_pkt = false;
1035         struct virtio_vsock_hdr *hdr;
1036         u32 len;
1037
1038         hdr = virtio_vsock_hdr(skb);
1039         len = le32_to_cpu(hdr->len);
1040
1041         spin_lock_bh(&vvs->rx_lock);
1042
1043         can_enqueue = virtio_transport_inc_rx_pkt(vvs, skb);
1044         if (!can_enqueue) {
1045                 free_pkt = true;
1046                 goto out;
1047         }
1048
1049         if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)
1050                 vvs->msg_count++;
1051
1052         /* Try to copy small packets into the buffer of last packet queued,
1053          * to avoid wasting memory queueing the entire buffer with a small
1054          * payload.
1055          */
1056         if (len <= GOOD_COPY_LEN && !skb_queue_empty(&vvs->rx_queue)) {
1057                 struct virtio_vsock_hdr *last_hdr;
1058                 struct sk_buff *last_skb;
1059
1060                 last_skb = skb_peek_tail(&vvs->rx_queue);
1061                 last_hdr = virtio_vsock_hdr(last_skb);
1062
1063                 /* If there is space in the last packet queued, we copy the
1064                  * new packet in its buffer. We avoid this if the last packet
1065                  * queued has VIRTIO_VSOCK_SEQ_EOM set, because this is
1066                  * delimiter of SEQPACKET message, so 'pkt' is the first packet
1067                  * of a new message.
1068                  */
1069                 if (skb->len < skb_tailroom(last_skb) &&
1070                     !(le32_to_cpu(last_hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)) {
1071                         memcpy(skb_put(last_skb, skb->len), skb->data, skb->len);
1072                         free_pkt = true;
1073                         last_hdr->flags |= hdr->flags;
1074                         last_hdr->len = cpu_to_le32(last_skb->len);
1075                         goto out;
1076                 }
1077         }
1078
1079         __skb_queue_tail(&vvs->rx_queue, skb);
1080
1081 out:
1082         spin_unlock_bh(&vvs->rx_lock);
1083         if (free_pkt)
1084                 kfree_skb(skb);
1085 }
1086
1087 static int
1088 virtio_transport_recv_connected(struct sock *sk,
1089                                 struct sk_buff *skb)
1090 {
1091         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1092         struct vsock_sock *vsk = vsock_sk(sk);
1093         int err = 0;
1094
1095         switch (le16_to_cpu(hdr->op)) {
1096         case VIRTIO_VSOCK_OP_RW:
1097                 virtio_transport_recv_enqueue(vsk, skb);
1098                 vsock_data_ready(sk);
1099                 return err;
1100         case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
1101                 virtio_transport_send_credit_update(vsk);
1102                 break;
1103         case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
1104                 sk->sk_write_space(sk);
1105                 break;
1106         case VIRTIO_VSOCK_OP_SHUTDOWN:
1107                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
1108                         vsk->peer_shutdown |= RCV_SHUTDOWN;
1109                 if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
1110                         vsk->peer_shutdown |= SEND_SHUTDOWN;
1111                 if (vsk->peer_shutdown == SHUTDOWN_MASK &&
1112                     vsock_stream_has_data(vsk) <= 0 &&
1113                     !sock_flag(sk, SOCK_DONE)) {
1114                         (void)virtio_transport_reset(vsk, NULL);
1115                         virtio_transport_do_close(vsk, true);
1116                 }
1117                 if (le32_to_cpu(virtio_vsock_hdr(skb)->flags))
1118                         sk->sk_state_change(sk);
1119                 break;
1120         case VIRTIO_VSOCK_OP_RST:
1121                 virtio_transport_do_close(vsk, true);
1122                 break;
1123         default:
1124                 err = -EINVAL;
1125                 break;
1126         }
1127
1128         kfree_skb(skb);
1129         return err;
1130 }
1131
1132 static void
1133 virtio_transport_recv_disconnecting(struct sock *sk,
1134                                     struct sk_buff *skb)
1135 {
1136         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1137         struct vsock_sock *vsk = vsock_sk(sk);
1138
1139         if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
1140                 virtio_transport_do_close(vsk, true);
1141 }
1142
1143 static int
1144 virtio_transport_send_response(struct vsock_sock *vsk,
1145                                struct sk_buff *skb)
1146 {
1147         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1148         struct virtio_vsock_pkt_info info = {
1149                 .op = VIRTIO_VSOCK_OP_RESPONSE,
1150                 .remote_cid = le64_to_cpu(hdr->src_cid),
1151                 .remote_port = le32_to_cpu(hdr->src_port),
1152                 .reply = true,
1153                 .vsk = vsk,
1154         };
1155
1156         return virtio_transport_send_pkt_info(vsk, &info);
1157 }
1158
1159 static bool virtio_transport_space_update(struct sock *sk,
1160                                           struct sk_buff *skb)
1161 {
1162         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1163         struct vsock_sock *vsk = vsock_sk(sk);
1164         struct virtio_vsock_sock *vvs = vsk->trans;
1165         bool space_available;
1166
1167         /* Listener sockets are not associated with any transport, so we are
1168          * not able to take the state to see if there is space available in the
1169          * remote peer, but since they are only used to receive requests, we
1170          * can assume that there is always space available in the other peer.
1171          */
1172         if (!vvs)
1173                 return true;
1174
1175         /* buf_alloc and fwd_cnt is always included in the hdr */
1176         spin_lock_bh(&vvs->tx_lock);
1177         vvs->peer_buf_alloc = le32_to_cpu(hdr->buf_alloc);
1178         vvs->peer_fwd_cnt = le32_to_cpu(hdr->fwd_cnt);
1179         space_available = virtio_transport_has_space(vsk);
1180         spin_unlock_bh(&vvs->tx_lock);
1181         return space_available;
1182 }
1183
1184 /* Handle server socket */
1185 static int
1186 virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
1187                              struct virtio_transport *t)
1188 {
1189         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1190         struct vsock_sock *vsk = vsock_sk(sk);
1191         struct vsock_sock *vchild;
1192         struct sock *child;
1193         int ret;
1194
1195         if (le16_to_cpu(hdr->op) != VIRTIO_VSOCK_OP_REQUEST) {
1196                 virtio_transport_reset_no_sock(t, skb);
1197                 return -EINVAL;
1198         }
1199
1200         if (sk_acceptq_is_full(sk)) {
1201                 virtio_transport_reset_no_sock(t, skb);
1202                 return -ENOMEM;
1203         }
1204
1205         child = vsock_create_connected(sk);
1206         if (!child) {
1207                 virtio_transport_reset_no_sock(t, skb);
1208                 return -ENOMEM;
1209         }
1210
1211         sk_acceptq_added(sk);
1212
1213         lock_sock_nested(child, SINGLE_DEPTH_NESTING);
1214
1215         child->sk_state = TCP_ESTABLISHED;
1216
1217         vchild = vsock_sk(child);
1218         vsock_addr_init(&vchild->local_addr, le64_to_cpu(hdr->dst_cid),
1219                         le32_to_cpu(hdr->dst_port));
1220         vsock_addr_init(&vchild->remote_addr, le64_to_cpu(hdr->src_cid),
1221                         le32_to_cpu(hdr->src_port));
1222
1223         ret = vsock_assign_transport(vchild, vsk);
1224         /* Transport assigned (looking at remote_addr) must be the same
1225          * where we received the request.
1226          */
1227         if (ret || vchild->transport != &t->transport) {
1228                 release_sock(child);
1229                 virtio_transport_reset_no_sock(t, skb);
1230                 sock_put(child);
1231                 return ret;
1232         }
1233
1234         if (virtio_transport_space_update(child, skb))
1235                 child->sk_write_space(child);
1236
1237         vsock_insert_connected(vchild);
1238         vsock_enqueue_accept(sk, child);
1239         virtio_transport_send_response(vchild, skb);
1240
1241         release_sock(child);
1242
1243         sk->sk_data_ready(sk);
1244         return 0;
1245 }
1246
1247 static bool virtio_transport_valid_type(u16 type)
1248 {
1249         return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
1250                (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
1251 }
1252
1253 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
1254  * lock.
1255  */
1256 void virtio_transport_recv_pkt(struct virtio_transport *t,
1257                                struct sk_buff *skb)
1258 {
1259         struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
1260         struct sockaddr_vm src, dst;
1261         struct vsock_sock *vsk;
1262         struct sock *sk;
1263         bool space_available;
1264
1265         vsock_addr_init(&src, le64_to_cpu(hdr->src_cid),
1266                         le32_to_cpu(hdr->src_port));
1267         vsock_addr_init(&dst, le64_to_cpu(hdr->dst_cid),
1268                         le32_to_cpu(hdr->dst_port));
1269
1270         trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
1271                                         dst.svm_cid, dst.svm_port,
1272                                         le32_to_cpu(hdr->len),
1273                                         le16_to_cpu(hdr->type),
1274                                         le16_to_cpu(hdr->op),
1275                                         le32_to_cpu(hdr->flags),
1276                                         le32_to_cpu(hdr->buf_alloc),
1277                                         le32_to_cpu(hdr->fwd_cnt));
1278
1279         if (!virtio_transport_valid_type(le16_to_cpu(hdr->type))) {
1280                 (void)virtio_transport_reset_no_sock(t, skb);
1281                 goto free_pkt;
1282         }
1283
1284         /* The socket must be in connected or bound table
1285          * otherwise send reset back
1286          */
1287         sk = vsock_find_connected_socket(&src, &dst);
1288         if (!sk) {
1289                 sk = vsock_find_bound_socket(&dst);
1290                 if (!sk) {
1291                         (void)virtio_transport_reset_no_sock(t, skb);
1292                         goto free_pkt;
1293                 }
1294         }
1295
1296         if (virtio_transport_get_type(sk) != le16_to_cpu(hdr->type)) {
1297                 (void)virtio_transport_reset_no_sock(t, skb);
1298                 sock_put(sk);
1299                 goto free_pkt;
1300         }
1301
1302         vsk = vsock_sk(sk);
1303
1304         lock_sock(sk);
1305
1306         /* Check if sk has been closed before lock_sock */
1307         if (sock_flag(sk, SOCK_DONE)) {
1308                 (void)virtio_transport_reset_no_sock(t, skb);
1309                 release_sock(sk);
1310                 sock_put(sk);
1311                 goto free_pkt;
1312         }
1313
1314         space_available = virtio_transport_space_update(sk, skb);
1315
1316         /* Update CID in case it has changed after a transport reset event */
1317         if (vsk->local_addr.svm_cid != VMADDR_CID_ANY)
1318                 vsk->local_addr.svm_cid = dst.svm_cid;
1319
1320         if (space_available)
1321                 sk->sk_write_space(sk);
1322
1323         switch (sk->sk_state) {
1324         case TCP_LISTEN:
1325                 virtio_transport_recv_listen(sk, skb, t);
1326                 kfree_skb(skb);
1327                 break;
1328         case TCP_SYN_SENT:
1329                 virtio_transport_recv_connecting(sk, skb);
1330                 kfree_skb(skb);
1331                 break;
1332         case TCP_ESTABLISHED:
1333                 virtio_transport_recv_connected(sk, skb);
1334                 break;
1335         case TCP_CLOSING:
1336                 virtio_transport_recv_disconnecting(sk, skb);
1337                 kfree_skb(skb);
1338                 break;
1339         default:
1340                 (void)virtio_transport_reset_no_sock(t, skb);
1341                 kfree_skb(skb);
1342                 break;
1343         }
1344
1345         release_sock(sk);
1346
1347         /* Release refcnt obtained when we fetched this socket out of the
1348          * bound or connected list.
1349          */
1350         sock_put(sk);
1351         return;
1352
1353 free_pkt:
1354         kfree_skb(skb);
1355 }
1356 EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
1357
1358 /* Remove skbs found in a queue that have a vsk that matches.
1359  *
1360  * Each skb is freed.
1361  *
1362  * Returns the count of skbs that were reply packets.
1363  */
1364 int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
1365 {
1366         struct sk_buff_head freeme;
1367         struct sk_buff *skb, *tmp;
1368         int cnt = 0;
1369
1370         skb_queue_head_init(&freeme);
1371
1372         spin_lock_bh(&queue->lock);
1373         skb_queue_walk_safe(queue, skb, tmp) {
1374                 if (vsock_sk(skb->sk) != vsk)
1375                         continue;
1376
1377                 __skb_unlink(skb, queue);
1378                 __skb_queue_tail(&freeme, skb);
1379
1380                 if (virtio_vsock_skb_reply(skb))
1381                         cnt++;
1382         }
1383         spin_unlock_bh(&queue->lock);
1384
1385         __skb_queue_purge(&freeme);
1386
1387         return cnt;
1388 }
1389 EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
1390
1391 MODULE_LICENSE("GPL v2");
1392 MODULE_AUTHOR("Asias He");
1393 MODULE_DESCRIPTION("common code for virtio vsock");