1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Hyper-V transport for vsock 4 * 5 * Hyper-V Sockets supplies a byte-stream based communication mechanism 6 * between the host and the VM. This driver implements the necessary 7 * support in the VM by introducing the new vsock transport. 8 * 9 * Copyright (c) 2017, Microsoft Corporation. 10 */ 11 #include <linux/module.h> 12 #include <linux/vmalloc.h> 13 #include <linux/hyperv.h> 14 #include <net/sock.h> 15 #include <net/af_vsock.h> 16 #include <hyperv/hvhdk.h> 17 18 /* Older (VMBUS version 'VERSION_WIN10' or before) Windows hosts have some 19 * stricter requirements on the hv_sock ring buffer size of six 4K pages. 20 * HV_HYP_PAGE_SIZE is defined as 4K. Newer hosts don't have this limitation; 21 * but, keep the defaults the same for compat. 22 */ 23 #define RINGBUFFER_HVS_RCV_SIZE (HV_HYP_PAGE_SIZE * 6) 24 #define RINGBUFFER_HVS_SND_SIZE (HV_HYP_PAGE_SIZE * 6) 25 #define RINGBUFFER_HVS_MAX_SIZE (HV_HYP_PAGE_SIZE * 64) 26 27 /* The MTU is 16KB per the host side's design */ 28 #define HVS_MTU_SIZE (1024 * 16) 29 30 /* How long to wait for graceful shutdown of a connection */ 31 #define HVS_CLOSE_TIMEOUT (8 * HZ) 32 33 struct vmpipe_proto_header { 34 u32 pkt_type; 35 u32 data_size; 36 }; 37 38 /* For recv, we use the VMBus in-place packet iterator APIs to directly copy 39 * data from the ringbuffer into the userspace buffer. 40 */ 41 struct hvs_recv_buf { 42 /* The header before the payload data */ 43 struct vmpipe_proto_header hdr; 44 45 /* The payload */ 46 u8 data[HVS_MTU_SIZE]; 47 }; 48 49 /* We can send up to HVS_MTU_SIZE bytes of payload to the host, but let's use 50 * a smaller size, i.e. HVS_SEND_BUF_SIZE, to maximize concurrency between the 51 * guest and the host processing as one VMBUS packet is the smallest processing 52 * unit. 53 * 54 * Note: the buffer can be eliminated in the future when we add new VMBus 55 * ringbuffer APIs that allow us to directly copy data from userspace buffer 56 * to VMBus ringbuffer. 57 */ 58 #define HVS_SEND_BUF_SIZE \ 59 (HV_HYP_PAGE_SIZE - sizeof(struct vmpipe_proto_header)) 60 61 struct hvs_send_buf { 62 /* The header before the payload data */ 63 struct vmpipe_proto_header hdr; 64 65 /* The payload */ 66 u8 data[HVS_SEND_BUF_SIZE]; 67 }; 68 69 #define HVS_HEADER_LEN (sizeof(struct vmpacket_descriptor) + \ 70 sizeof(struct vmpipe_proto_header)) 71 72 /* See 'prev_indices' in hv_ringbuffer_read(), hv_ringbuffer_write(), and 73 * __hv_pkt_iter_next(). 74 */ 75 #define VMBUS_PKT_TRAILER_SIZE (sizeof(u64)) 76 77 #define HVS_PKT_LEN(payload_len) (HVS_HEADER_LEN + \ 78 ALIGN((payload_len), 8) + \ 79 VMBUS_PKT_TRAILER_SIZE) 80 81 /* Upper bound on the size of a VMbus packet for hv_sock */ 82 #define HVS_MAX_PKT_SIZE HVS_PKT_LEN(HVS_MTU_SIZE) 83 84 union hvs_service_id { 85 guid_t srv_id; 86 87 struct { 88 unsigned int svm_port; 89 unsigned char b[sizeof(guid_t) - sizeof(unsigned int)]; 90 }; 91 }; 92 93 /* Per-socket state (accessed via vsk->trans) */ 94 struct hvsock { 95 struct vsock_sock *vsk; 96 97 guid_t vm_srv_id; 98 guid_t host_srv_id; 99 100 struct vmbus_channel *chan; 101 struct vmpacket_descriptor *recv_desc; 102 103 /* The length of the payload not delivered to userland yet */ 104 u32 recv_data_len; 105 /* The offset of the payload */ 106 u32 recv_data_off; 107 108 /* Have we sent the zero-length packet (FIN)? */ 109 bool fin_sent; 110 }; 111 112 /* In the VM, we support Hyper-V Sockets with AF_VSOCK, and the endpoint is 113 * <cid, port> (see struct sockaddr_vm). Note: cid is not really used here: 114 * when we write apps to connect to the host, we can only use VMADDR_CID_ANY 115 * or VMADDR_CID_HOST (both are equivalent) as the remote cid, and when we 116 * write apps to bind() & listen() in the VM, we can only use VMADDR_CID_ANY 117 * as the local cid. 118 * 119 * On the host, Hyper-V Sockets are supported by Winsock AF_HYPERV: 120 * https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/user- 121 * guide/make-integration-service, and the endpoint is <VmID, ServiceId> with 122 * the below sockaddr: 123 * 124 * struct SOCKADDR_HV 125 * { 126 * ADDRESS_FAMILY Family; 127 * USHORT Reserved; 128 * GUID VmId; 129 * GUID ServiceId; 130 * }; 131 * Note: VmID is not used by Linux VM and actually it isn't transmitted via 132 * VMBus, because here it's obvious the host and the VM can easily identify 133 * each other. Though the VmID is useful on the host, especially in the case 134 * of Windows container, Linux VM doesn't need it at all. 135 * 136 * To make use of the AF_VSOCK infrastructure in Linux VM, we have to limit 137 * the available GUID space of SOCKADDR_HV so that we can create a mapping 138 * between AF_VSOCK port and SOCKADDR_HV Service GUID. The rule of writing 139 * Hyper-V Sockets apps on the host and in Linux VM is: 140 * 141 **************************************************************************** 142 * The only valid Service GUIDs, from the perspectives of both the host and * 143 * Linux VM, that can be connected by the other end, must conform to this * 144 * format: <port>-facb-11e6-bd58-64006a7986d3. * 145 **************************************************************************** 146 * 147 * When we write apps on the host to connect(), the GUID ServiceID is used. 148 * When we write apps in Linux VM to connect(), we only need to specify the 149 * port and the driver will form the GUID and use that to request the host. 150 * 151 */ 152 153 /* 00000000-facb-11e6-bd58-64006a7986d3 */ 154 static const guid_t srv_id_template = 155 GUID_INIT(0x00000000, 0xfacb, 0x11e6, 0xbd, 0x58, 156 0x64, 0x00, 0x6a, 0x79, 0x86, 0xd3); 157 158 static bool hvs_check_transport(struct vsock_sock *vsk); 159 160 static bool is_valid_srv_id(const guid_t *id) 161 { 162 return !memcmp(&id->b[4], &srv_id_template.b[4], sizeof(guid_t) - 4); 163 } 164 165 static unsigned int get_port_by_srv_id(const guid_t *svr_id) 166 { 167 return *((unsigned int *)svr_id); 168 } 169 170 static void hvs_addr_init(struct sockaddr_vm *addr, const guid_t *svr_id) 171 { 172 unsigned int port = get_port_by_srv_id(svr_id); 173 174 vsock_addr_init(addr, VMADDR_CID_ANY, port); 175 } 176 177 static void hvs_set_channel_pending_send_size(struct vmbus_channel *chan) 178 { 179 set_channel_pending_send_size(chan, 180 HVS_PKT_LEN(HVS_SEND_BUF_SIZE)); 181 182 virt_mb(); 183 } 184 185 static bool hvs_channel_readable(struct vmbus_channel *chan) 186 { 187 u32 readable = hv_get_bytes_to_read(&chan->inbound); 188 189 /* 0-size payload means FIN */ 190 return readable >= HVS_PKT_LEN(0); 191 } 192 193 static int hvs_channel_readable_payload(struct vmbus_channel *chan) 194 { 195 u32 readable = hv_get_bytes_to_read(&chan->inbound); 196 197 if (readable > HVS_PKT_LEN(0)) { 198 /* At least we have 1 byte to read. We don't need to return 199 * the exact readable bytes: see vsock_connectible_recvmsg() -> 200 * vsock_stream_has_data(). 201 */ 202 return 1; 203 } 204 205 if (readable == HVS_PKT_LEN(0)) { 206 /* 0-size payload means FIN */ 207 return 0; 208 } 209 210 /* No payload or FIN */ 211 return -1; 212 } 213 214 static size_t hvs_channel_writable_bytes(struct vmbus_channel *chan) 215 { 216 u32 writeable = hv_get_bytes_to_write(&chan->outbound); 217 size_t ret; 218 219 /* The ringbuffer mustn't be 100% full, and we should reserve a 220 * zero-length-payload packet for the FIN: see hv_ringbuffer_write() 221 * and hvs_shutdown(). 222 */ 223 if (writeable <= HVS_PKT_LEN(1) + HVS_PKT_LEN(0)) 224 return 0; 225 226 ret = writeable - HVS_PKT_LEN(1) - HVS_PKT_LEN(0); 227 228 return round_down(ret, 8); 229 } 230 231 static int __hvs_send_data(struct vmbus_channel *chan, 232 struct vmpipe_proto_header *hdr, 233 size_t to_write) 234 { 235 hdr->pkt_type = 1; 236 hdr->data_size = to_write; 237 return vmbus_sendpacket(chan, hdr, sizeof(*hdr) + to_write, 238 0, VM_PKT_DATA_INBAND, 0); 239 } 240 241 static int hvs_send_data(struct vmbus_channel *chan, 242 struct hvs_send_buf *send_buf, size_t to_write) 243 { 244 return __hvs_send_data(chan, &send_buf->hdr, to_write); 245 } 246 247 static void hvs_channel_cb(void *ctx) 248 { 249 struct sock *sk = (struct sock *)ctx; 250 struct vsock_sock *vsk = vsock_sk(sk); 251 struct hvsock *hvs = vsk->trans; 252 struct vmbus_channel *chan = hvs->chan; 253 254 if (hvs_channel_readable(chan)) 255 sk->sk_data_ready(sk); 256 257 if (hv_get_bytes_to_write(&chan->outbound) > 0) 258 sk->sk_write_space(sk); 259 } 260 261 static void hvs_do_close_lock_held(struct vsock_sock *vsk, 262 bool cancel_timeout) 263 { 264 struct sock *sk = sk_vsock(vsk); 265 266 sock_set_flag(sk, SOCK_DONE); 267 WRITE_ONCE(vsk->peer_shutdown, SHUTDOWN_MASK); 268 if (vsock_stream_has_data(vsk) <= 0) 269 sk->sk_state = TCP_CLOSING; 270 sk->sk_state_change(sk); 271 if (vsk->close_work_scheduled && 272 (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) { 273 vsk->close_work_scheduled = false; 274 vsock_remove_sock(vsk); 275 276 /* Release the reference taken while scheduling the timeout */ 277 sock_put(sk); 278 } 279 } 280 281 static void hvs_close_connection(struct vmbus_channel *chan) 282 { 283 struct sock *sk = get_per_channel_state(chan); 284 285 lock_sock(sk); 286 hvs_do_close_lock_held(vsock_sk(sk), true); 287 release_sock(sk); 288 289 /* Release the refcnt for the channel that's opened in 290 * hvs_open_connection(). 291 */ 292 sock_put(sk); 293 } 294 295 static void hvs_open_connection(struct vmbus_channel *chan) 296 { 297 guid_t *if_instance, *if_type; 298 unsigned char conn_from_host; 299 300 struct sockaddr_vm addr; 301 struct sock *sk, *new = NULL; 302 struct vsock_sock *vnew = NULL; 303 struct hvsock *hvs = NULL; 304 struct hvsock *hvs_new = NULL; 305 int rcvbuf; 306 int ret; 307 int sndbuf; 308 309 if_type = &chan->offermsg.offer.if_type; 310 if_instance = &chan->offermsg.offer.if_instance; 311 conn_from_host = chan->offermsg.offer.u.pipe.user_def[0]; 312 if (!is_valid_srv_id(if_type)) 313 return; 314 315 hvs_addr_init(&addr, conn_from_host ? if_type : if_instance); 316 sk = vsock_find_bound_socket(&addr); 317 if (!sk) 318 return; 319 320 lock_sock(sk); 321 if ((conn_from_host && sk->sk_state != TCP_LISTEN) || 322 (!conn_from_host && sk->sk_state != TCP_SYN_SENT)) 323 goto out; 324 325 if (conn_from_host) { 326 if (sk_acceptq_is_full(sk)) 327 goto out; 328 329 new = vsock_create_connected(sk); 330 if (!new) 331 goto out; 332 333 new->sk_state = TCP_SYN_SENT; 334 vnew = vsock_sk(new); 335 336 hvs_addr_init(&vnew->local_addr, if_type); 337 338 /* Remote peer is always the host */ 339 vsock_addr_init(&vnew->remote_addr, 340 VMADDR_CID_HOST, VMADDR_PORT_ANY); 341 vnew->remote_addr.svm_port = get_port_by_srv_id(if_instance); 342 ret = vsock_assign_transport(vnew, vsock_sk(sk)); 343 /* Transport assigned (looking at remote_addr) must be the 344 * same where we received the request. 345 */ 346 if (ret || !hvs_check_transport(vnew)) { 347 sock_put(new); 348 goto out; 349 } 350 hvs_new = vnew->trans; 351 hvs_new->chan = chan; 352 } else { 353 hvs = vsock_sk(sk)->trans; 354 hvs->chan = chan; 355 } 356 357 set_channel_read_mode(chan, HV_CALL_DIRECT); 358 359 /* Use the socket buffer sizes as hints for the VMBUS ring size. For 360 * server side sockets, 'sk' is the parent socket and thus, this will 361 * allow the child sockets to inherit the size from the parent. Keep 362 * the mins to the default value and align to page size as per VMBUS 363 * requirements. 364 * For the max, the socket core library will limit the socket buffer 365 * size that can be set by the user, but, since currently, the hv_sock 366 * VMBUS ring buffer is physically contiguous allocation, restrict it 367 * further. 368 * Older versions of hv_sock host side code cannot handle bigger VMBUS 369 * ring buffer size. Use the version number to limit the change to newer 370 * versions. 371 */ 372 if (vmbus_proto_version < VERSION_WIN10_V5) { 373 sndbuf = RINGBUFFER_HVS_SND_SIZE; 374 rcvbuf = RINGBUFFER_HVS_RCV_SIZE; 375 } else { 376 sndbuf = max_t(int, sk->sk_sndbuf, RINGBUFFER_HVS_SND_SIZE); 377 sndbuf = min_t(int, sndbuf, RINGBUFFER_HVS_MAX_SIZE); 378 sndbuf = VMBUS_RING_SIZE(sndbuf); 379 rcvbuf = max_t(int, sk->sk_rcvbuf, RINGBUFFER_HVS_RCV_SIZE); 380 rcvbuf = min_t(int, rcvbuf, RINGBUFFER_HVS_MAX_SIZE); 381 rcvbuf = VMBUS_RING_SIZE(rcvbuf); 382 } 383 384 chan->max_pkt_size = HVS_MAX_PKT_SIZE; 385 386 ret = vmbus_open(chan, sndbuf, rcvbuf, NULL, 0, hvs_channel_cb, 387 conn_from_host ? new : sk); 388 if (ret != 0) { 389 if (conn_from_host) { 390 hvs_new->chan = NULL; 391 sock_put(new); 392 } else { 393 hvs->chan = NULL; 394 } 395 goto out; 396 } 397 398 set_per_channel_state(chan, conn_from_host ? new : sk); 399 400 /* This reference will be dropped by hvs_close_connection(). */ 401 sock_hold(conn_from_host ? new : sk); 402 vmbus_set_chn_rescind_callback(chan, hvs_close_connection); 403 404 /* Set the pending send size to max packet size to always get 405 * notifications from the host when there is enough writable space. 406 * The host is optimized to send notifications only when the pending 407 * size boundary is crossed, and not always. 408 */ 409 hvs_set_channel_pending_send_size(chan); 410 411 if (conn_from_host) { 412 new->sk_state = TCP_ESTABLISHED; 413 414 hvs_new->vm_srv_id = *if_type; 415 hvs_new->host_srv_id = *if_instance; 416 417 vsock_insert_connected(vnew); 418 419 vsock_enqueue_accept(sk, new); 420 } else { 421 sk->sk_state = TCP_ESTABLISHED; 422 sk->sk_socket->state = SS_CONNECTED; 423 424 vsock_insert_connected(vsock_sk(sk)); 425 } 426 427 sk->sk_state_change(sk); 428 429 out: 430 /* Release refcnt obtained when we called vsock_find_bound_socket() */ 431 sock_put(sk); 432 433 release_sock(sk); 434 } 435 436 static u32 hvs_get_local_cid(void) 437 { 438 return VMADDR_CID_ANY; 439 } 440 441 static int hvs_sock_init(struct vsock_sock *vsk, struct vsock_sock *psk) 442 { 443 struct hvsock *hvs; 444 struct sock *sk = sk_vsock(vsk); 445 446 hvs = kzalloc_obj(*hvs); 447 if (!hvs) 448 return -ENOMEM; 449 450 vsk->trans = hvs; 451 hvs->vsk = vsk; 452 sk->sk_sndbuf = RINGBUFFER_HVS_SND_SIZE; 453 sk->sk_rcvbuf = RINGBUFFER_HVS_RCV_SIZE; 454 return 0; 455 } 456 457 static int hvs_connect(struct vsock_sock *vsk) 458 { 459 union hvs_service_id vm, host; 460 struct hvsock *h = vsk->trans; 461 462 vm.srv_id = srv_id_template; 463 vm.svm_port = vsk->local_addr.svm_port; 464 h->vm_srv_id = vm.srv_id; 465 466 host.srv_id = srv_id_template; 467 host.svm_port = vsk->remote_addr.svm_port; 468 h->host_srv_id = host.srv_id; 469 470 return vmbus_send_tl_connect_request(&h->vm_srv_id, &h->host_srv_id); 471 } 472 473 static void hvs_shutdown_lock_held(struct hvsock *hvs, int mode) 474 { 475 struct vmpipe_proto_header hdr; 476 477 if (hvs->fin_sent || !hvs->chan) 478 return; 479 480 /* It can't fail: see hvs_channel_writable_bytes(). */ 481 (void)__hvs_send_data(hvs->chan, &hdr, 0); 482 hvs->fin_sent = true; 483 } 484 485 static int hvs_shutdown(struct vsock_sock *vsk, int mode) 486 { 487 if (!(mode & SEND_SHUTDOWN)) 488 return 0; 489 490 hvs_shutdown_lock_held(vsk->trans, mode); 491 return 0; 492 } 493 494 static void hvs_close_timeout(struct work_struct *work) 495 { 496 struct vsock_sock *vsk = 497 container_of(work, struct vsock_sock, close_work.work); 498 struct sock *sk = sk_vsock(vsk); 499 500 sock_hold(sk); 501 lock_sock(sk); 502 if (!sock_flag(sk, SOCK_DONE)) 503 hvs_do_close_lock_held(vsk, false); 504 505 vsk->close_work_scheduled = false; 506 release_sock(sk); 507 sock_put(sk); 508 } 509 510 /* Returns true, if it is safe to remove socket; false otherwise */ 511 static bool hvs_close_lock_held(struct vsock_sock *vsk) 512 { 513 struct sock *sk = sk_vsock(vsk); 514 515 if (!(sk->sk_state == TCP_ESTABLISHED || 516 sk->sk_state == TCP_CLOSING)) 517 return true; 518 519 if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK) 520 hvs_shutdown_lock_held(vsk->trans, SHUTDOWN_MASK); 521 522 if (sock_flag(sk, SOCK_DONE)) 523 return true; 524 525 /* This reference will be dropped by the delayed close routine */ 526 sock_hold(sk); 527 INIT_DELAYED_WORK(&vsk->close_work, hvs_close_timeout); 528 vsk->close_work_scheduled = true; 529 schedule_delayed_work(&vsk->close_work, HVS_CLOSE_TIMEOUT); 530 return false; 531 } 532 533 static void hvs_release(struct vsock_sock *vsk) 534 { 535 bool remove_sock; 536 537 remove_sock = hvs_close_lock_held(vsk); 538 if (remove_sock) 539 vsock_remove_sock(vsk); 540 } 541 542 static void hvs_destruct(struct vsock_sock *vsk) 543 { 544 struct hvsock *hvs = vsk->trans; 545 struct vmbus_channel *chan = hvs->chan; 546 547 if (chan) 548 vmbus_hvsock_device_unregister(chan); 549 550 kfree(hvs); 551 vsk->trans = NULL; 552 } 553 554 static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr) 555 { 556 return -EOPNOTSUPP; 557 } 558 559 static int hvs_dgram_dequeue(struct vsock_sock *vsk, struct msghdr *msg, 560 size_t len, int flags) 561 { 562 return -EOPNOTSUPP; 563 } 564 565 static int hvs_dgram_enqueue(struct vsock_sock *vsk, 566 struct sockaddr_vm *remote, struct msghdr *msg, 567 size_t dgram_len) 568 { 569 return -EOPNOTSUPP; 570 } 571 572 static bool hvs_dgram_allow(struct vsock_sock *vsk, u32 cid, u32 port) 573 { 574 return false; 575 } 576 577 static int hvs_update_recv_data(struct hvsock *hvs) 578 { 579 struct hvs_recv_buf *recv_buf; 580 u32 pkt_len, payload_len; 581 582 pkt_len = hv_pkt_len(hvs->recv_desc); 583 584 if (pkt_len < HVS_HEADER_LEN) 585 return -EIO; 586 587 recv_buf = (struct hvs_recv_buf *)(hvs->recv_desc + 1); 588 payload_len = recv_buf->hdr.data_size; 589 590 if (payload_len > pkt_len - HVS_HEADER_LEN || 591 payload_len > HVS_MTU_SIZE) 592 return -EIO; 593 594 if (payload_len == 0) 595 WRITE_ONCE(hvs->vsk->peer_shutdown, 596 READ_ONCE(hvs->vsk->peer_shutdown) | 597 SEND_SHUTDOWN); 598 599 hvs->recv_data_len = payload_len; 600 hvs->recv_data_off = 0; 601 602 return 0; 603 } 604 605 static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg, 606 size_t len, int flags) 607 { 608 struct hvsock *hvs = vsk->trans; 609 bool need_refill = !hvs->recv_desc; 610 struct hvs_recv_buf *recv_buf; 611 u32 to_read; 612 int ret; 613 614 if (flags & MSG_PEEK) 615 return -EOPNOTSUPP; 616 617 if (need_refill) { 618 hvs->recv_desc = hv_pkt_iter_first(hvs->chan); 619 if (!hvs->recv_desc) 620 return -ENOBUFS; 621 ret = hvs_update_recv_data(hvs); 622 if (ret) 623 return ret; 624 } 625 626 recv_buf = (struct hvs_recv_buf *)(hvs->recv_desc + 1); 627 to_read = min_t(u32, len, hvs->recv_data_len); 628 ret = memcpy_to_msg(msg, recv_buf->data + hvs->recv_data_off, to_read); 629 if (ret != 0) 630 return ret; 631 632 hvs->recv_data_len -= to_read; 633 if (hvs->recv_data_len == 0) { 634 hvs->recv_desc = hv_pkt_iter_next(hvs->chan, hvs->recv_desc); 635 if (hvs->recv_desc) { 636 ret = hvs_update_recv_data(hvs); 637 if (ret) 638 return ret; 639 } 640 } else { 641 hvs->recv_data_off += to_read; 642 } 643 644 return to_read; 645 } 646 647 static ssize_t hvs_stream_enqueue(struct vsock_sock *vsk, struct msghdr *msg, 648 size_t len) 649 { 650 struct hvsock *hvs = vsk->trans; 651 struct vmbus_channel *chan = hvs->chan; 652 struct hvs_send_buf *send_buf; 653 ssize_t to_write, max_writable; 654 ssize_t ret = 0; 655 ssize_t bytes_written = 0; 656 657 BUILD_BUG_ON(sizeof(*send_buf) != HV_HYP_PAGE_SIZE); 658 659 send_buf = kmalloc_obj(*send_buf); 660 if (!send_buf) 661 return -ENOMEM; 662 663 /* Reader(s) could be draining data from the channel as we write. 664 * Maximize bandwidth, by iterating until the channel is found to be 665 * full. 666 */ 667 while (len) { 668 max_writable = hvs_channel_writable_bytes(chan); 669 if (!max_writable) 670 break; 671 to_write = min_t(ssize_t, len, max_writable); 672 to_write = min_t(ssize_t, to_write, HVS_SEND_BUF_SIZE); 673 /* memcpy_from_msg is safe for loop as it advances the offsets 674 * within the message iterator. 675 */ 676 ret = memcpy_from_msg(send_buf->data, msg, to_write); 677 if (ret < 0) 678 goto out; 679 680 ret = hvs_send_data(hvs->chan, send_buf, to_write); 681 if (ret < 0) 682 goto out; 683 684 bytes_written += to_write; 685 len -= to_write; 686 } 687 out: 688 /* If any data has been sent, return that */ 689 if (bytes_written) 690 ret = bytes_written; 691 kfree(send_buf); 692 return ret; 693 } 694 695 static s64 hvs_stream_has_data(struct vsock_sock *vsk) 696 { 697 struct hvsock *hvs = vsk->trans; 698 s64 ret; 699 700 if (hvs->recv_data_len > 0) 701 return hvs->recv_data_len; 702 703 switch (hvs_channel_readable_payload(hvs->chan)) { 704 case 1: 705 if (hvs->recv_desc) { 706 /* Here hvs->recv_data_len is 0, so hvs->recv_desc must 707 * be NULL unless it points to the 0-byte-payload FIN 708 * packet or a malformed/short packet: see 709 * hvs_update_recv_data(). 710 * 711 * If hvs->recv_desc points to the FIN packet, here all 712 * the payload has been dequeued and the peer_shutdown 713 * flag is set, but hvs_channel_readable_payload() still 714 * returns 1, because the VMBus ringbuffer's read_index 715 * is not updated for the FIN packet: 716 * hvs_stream_dequeue() -> hv_pkt_iter_next() updates 717 * the cached priv_read_index but has no opportunity to 718 * update the read_index in hv_pkt_iter_close() as 719 * hvs_stream_has_data() returns 0 for the FIN packet, 720 * so it won't get dequeued. 721 * 722 * In case hvs->recv_desc points to a malformed/short 723 * packet, return -EIO. 724 */ 725 if (!(vsk->peer_shutdown & SEND_SHUTDOWN)) 726 return -EIO; 727 728 return 0; 729 } 730 731 hvs->recv_desc = hv_pkt_iter_first(hvs->chan); 732 if (!hvs->recv_desc) 733 return -ENOBUFS; 734 735 ret = hvs_update_recv_data(hvs); 736 if (ret) 737 return ret; 738 return hvs->recv_data_len; 739 case 0: 740 WRITE_ONCE(vsk->peer_shutdown, 741 READ_ONCE(vsk->peer_shutdown) | SEND_SHUTDOWN); 742 ret = 0; 743 break; 744 default: /* -1 */ 745 ret = 0; 746 break; 747 } 748 749 return ret; 750 } 751 752 static s64 hvs_stream_has_space(struct vsock_sock *vsk) 753 { 754 struct hvsock *hvs = vsk->trans; 755 756 return hvs_channel_writable_bytes(hvs->chan); 757 } 758 759 static u64 hvs_stream_rcvhiwat(struct vsock_sock *vsk) 760 { 761 return HVS_MTU_SIZE + 1; 762 } 763 764 static bool hvs_stream_is_active(struct vsock_sock *vsk) 765 { 766 struct hvsock *hvs = vsk->trans; 767 768 return hvs->chan != NULL; 769 } 770 771 static bool hvs_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port) 772 { 773 if (!vsock_net_mode_global(vsk)) 774 return false; 775 776 if (cid == VMADDR_CID_HOST) 777 return true; 778 779 return false; 780 } 781 782 static 783 int hvs_notify_poll_in(struct vsock_sock *vsk, size_t target, bool *readable) 784 { 785 struct hvsock *hvs = vsk->trans; 786 787 *readable = hvs_channel_readable(hvs->chan); 788 return 0; 789 } 790 791 static 792 int hvs_notify_poll_out(struct vsock_sock *vsk, size_t target, bool *writable) 793 { 794 *writable = hvs_stream_has_space(vsk) > 0; 795 796 return 0; 797 } 798 799 static 800 int hvs_notify_recv_init(struct vsock_sock *vsk, size_t target, 801 struct vsock_transport_recv_notify_data *d) 802 { 803 return 0; 804 } 805 806 static 807 int hvs_notify_recv_pre_block(struct vsock_sock *vsk, size_t target, 808 struct vsock_transport_recv_notify_data *d) 809 { 810 return 0; 811 } 812 813 static 814 int hvs_notify_recv_pre_dequeue(struct vsock_sock *vsk, size_t target, 815 struct vsock_transport_recv_notify_data *d) 816 { 817 return 0; 818 } 819 820 static 821 int hvs_notify_recv_post_dequeue(struct vsock_sock *vsk, size_t target, 822 ssize_t copied, bool data_read, 823 struct vsock_transport_recv_notify_data *d) 824 { 825 return 0; 826 } 827 828 static 829 int hvs_notify_send_init(struct vsock_sock *vsk, 830 struct vsock_transport_send_notify_data *d) 831 { 832 return 0; 833 } 834 835 static 836 int hvs_notify_send_pre_block(struct vsock_sock *vsk, 837 struct vsock_transport_send_notify_data *d) 838 { 839 return 0; 840 } 841 842 static 843 int hvs_notify_send_pre_enqueue(struct vsock_sock *vsk, 844 struct vsock_transport_send_notify_data *d) 845 { 846 return 0; 847 } 848 849 static 850 int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written, 851 struct vsock_transport_send_notify_data *d) 852 { 853 return 0; 854 } 855 856 static 857 int hvs_notify_set_rcvlowat(struct vsock_sock *vsk, int val) 858 { 859 return -EOPNOTSUPP; 860 } 861 862 static struct vsock_transport hvs_transport = { 863 .module = THIS_MODULE, 864 865 .get_local_cid = hvs_get_local_cid, 866 867 .init = hvs_sock_init, 868 .destruct = hvs_destruct, 869 .release = hvs_release, 870 .connect = hvs_connect, 871 .shutdown = hvs_shutdown, 872 873 .dgram_bind = hvs_dgram_bind, 874 .dgram_dequeue = hvs_dgram_dequeue, 875 .dgram_enqueue = hvs_dgram_enqueue, 876 .dgram_allow = hvs_dgram_allow, 877 878 .stream_dequeue = hvs_stream_dequeue, 879 .stream_enqueue = hvs_stream_enqueue, 880 .stream_has_data = hvs_stream_has_data, 881 .stream_has_space = hvs_stream_has_space, 882 .stream_rcvhiwat = hvs_stream_rcvhiwat, 883 .stream_is_active = hvs_stream_is_active, 884 .stream_allow = hvs_stream_allow, 885 886 .notify_poll_in = hvs_notify_poll_in, 887 .notify_poll_out = hvs_notify_poll_out, 888 .notify_recv_init = hvs_notify_recv_init, 889 .notify_recv_pre_block = hvs_notify_recv_pre_block, 890 .notify_recv_pre_dequeue = hvs_notify_recv_pre_dequeue, 891 .notify_recv_post_dequeue = hvs_notify_recv_post_dequeue, 892 .notify_send_init = hvs_notify_send_init, 893 .notify_send_pre_block = hvs_notify_send_pre_block, 894 .notify_send_pre_enqueue = hvs_notify_send_pre_enqueue, 895 .notify_send_post_enqueue = hvs_notify_send_post_enqueue, 896 897 .notify_set_rcvlowat = hvs_notify_set_rcvlowat 898 }; 899 900 static bool hvs_check_transport(struct vsock_sock *vsk) 901 { 902 return vsk->transport == &hvs_transport; 903 } 904 905 static int hvs_probe(struct hv_device *hdev, 906 const struct hv_vmbus_device_id *dev_id) 907 { 908 struct vmbus_channel *chan = hdev->channel; 909 910 hvs_open_connection(chan); 911 912 /* Always return success to suppress the unnecessary error message 913 * in vmbus_probe(): on error the host will rescind the device in 914 * 30 seconds and we can do cleanup at that time in 915 * vmbus_onoffer_rescind(). 916 */ 917 return 0; 918 } 919 920 static void hvs_remove(struct hv_device *hdev) 921 { 922 struct vmbus_channel *chan = hdev->channel; 923 924 vmbus_close(chan); 925 } 926 927 /* hv_sock connections can not persist across hibernation, and all the hv_sock 928 * channels are forced to be rescinded before hibernation: see 929 * vmbus_bus_suspend(). Here the dummy hvs_suspend() and hvs_resume() 930 * are only needed because hibernation requires that every vmbus device's 931 * driver should have a .suspend and .resume callback: see vmbus_suspend(). 932 */ 933 static int hvs_suspend(struct hv_device *hv_dev) 934 { 935 /* Dummy */ 936 return 0; 937 } 938 939 static int hvs_resume(struct hv_device *dev) 940 { 941 /* Dummy */ 942 return 0; 943 } 944 945 /* This isn't really used. See vmbus_match() and vmbus_probe() */ 946 static const struct hv_vmbus_device_id id_table[] = { 947 {}, 948 }; 949 950 static struct hv_driver hvs_drv = { 951 .name = "hv_sock", 952 .hvsock = true, 953 .id_table = id_table, 954 .probe = hvs_probe, 955 .remove = hvs_remove, 956 .suspend = hvs_suspend, 957 .resume = hvs_resume, 958 }; 959 960 static int __init hvs_init(void) 961 { 962 int ret; 963 964 if (vmbus_proto_version < VERSION_WIN10) 965 return -ENODEV; 966 967 ret = vmbus_driver_register(&hvs_drv); 968 if (ret != 0) 969 return ret; 970 971 ret = vsock_core_register(&hvs_transport, VSOCK_TRANSPORT_F_G2H); 972 if (ret) { 973 vmbus_driver_unregister(&hvs_drv); 974 return ret; 975 } 976 977 return 0; 978 } 979 980 static void __exit hvs_exit(void) 981 { 982 vsock_core_unregister(&hvs_transport); 983 vmbus_driver_unregister(&hvs_drv); 984 } 985 986 module_init(hvs_init); 987 module_exit(hvs_exit); 988 989 MODULE_DESCRIPTION("Hyper-V Sockets"); 990 MODULE_VERSION("1.0.0"); 991 MODULE_LICENSE("GPL"); 992 MODULE_ALIAS_NETPROTO(PF_VSOCK); 993