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