1 /* Copyright (C) 2009 Red Hat, Inc. 2 * Author: Michael S. Tsirkin <mst@redhat.com> 3 * 4 * This work is licensed under the terms of the GNU GPL, version 2. 5 * 6 * virtio-net server in host kernel. 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/eventfd.h> 11 #include <linux/vhost.h> 12 #include <linux/virtio_net.h> 13 #include <linux/mmu_context.h> 14 #include <linux/miscdevice.h> 15 #include <linux/module.h> 16 #include <linux/mutex.h> 17 #include <linux/workqueue.h> 18 #include <linux/rcupdate.h> 19 #include <linux/file.h> 20 #include <linux/slab.h> 21 22 #include <linux/net.h> 23 #include <linux/if_packet.h> 24 #include <linux/if_arp.h> 25 #include <linux/if_tun.h> 26 #include <linux/if_macvlan.h> 27 28 #include <net/sock.h> 29 30 #include "vhost.h" 31 32 /* Max number of bytes transferred before requeueing the job. 33 * Using this limit prevents one virtqueue from starving others. */ 34 #define VHOST_NET_WEIGHT 0x80000 35 36 enum { 37 VHOST_NET_VQ_RX = 0, 38 VHOST_NET_VQ_TX = 1, 39 VHOST_NET_VQ_MAX = 2, 40 }; 41 42 enum vhost_net_poll_state { 43 VHOST_NET_POLL_DISABLED = 0, 44 VHOST_NET_POLL_STARTED = 1, 45 VHOST_NET_POLL_STOPPED = 2, 46 }; 47 48 struct vhost_net { 49 struct vhost_dev dev; 50 struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX]; 51 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 52 /* Tells us whether we are polling a socket for TX. 53 * We only do this when socket buffer fills up. 54 * Protected by tx vq lock. */ 55 enum vhost_net_poll_state tx_poll_state; 56 }; 57 58 /* Pop first len bytes from iovec. Return number of segments used. */ 59 static int move_iovec_hdr(struct iovec *from, struct iovec *to, 60 size_t len, int iov_count) 61 { 62 int seg = 0; 63 size_t size; 64 while (len && seg < iov_count) { 65 size = min(from->iov_len, len); 66 to->iov_base = from->iov_base; 67 to->iov_len = size; 68 from->iov_len -= size; 69 from->iov_base += size; 70 len -= size; 71 ++from; 72 ++to; 73 ++seg; 74 } 75 return seg; 76 } 77 /* Copy iovec entries for len bytes from iovec. */ 78 static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, 79 size_t len, int iovcount) 80 { 81 int seg = 0; 82 size_t size; 83 while (len && seg < iovcount) { 84 size = min(from->iov_len, len); 85 to->iov_base = from->iov_base; 86 to->iov_len = size; 87 len -= size; 88 ++from; 89 ++to; 90 ++seg; 91 } 92 } 93 94 /* Caller must have TX VQ lock */ 95 static void tx_poll_stop(struct vhost_net *net) 96 { 97 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) 98 return; 99 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); 100 net->tx_poll_state = VHOST_NET_POLL_STOPPED; 101 } 102 103 /* Caller must have TX VQ lock */ 104 static void tx_poll_start(struct vhost_net *net, struct socket *sock) 105 { 106 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) 107 return; 108 vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); 109 net->tx_poll_state = VHOST_NET_POLL_STARTED; 110 } 111 112 /* Expects to be always run from workqueue - which acts as 113 * read-size critical section for our kind of RCU. */ 114 static void handle_tx(struct vhost_net *net) 115 { 116 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; 117 unsigned out, in, s; 118 int head; 119 struct msghdr msg = { 120 .msg_name = NULL, 121 .msg_namelen = 0, 122 .msg_control = NULL, 123 .msg_controllen = 0, 124 .msg_iov = vq->iov, 125 .msg_flags = MSG_DONTWAIT, 126 }; 127 size_t len, total_len = 0; 128 int err, wmem; 129 size_t hdr_size; 130 struct socket *sock; 131 132 /* TODO: check that we are running from vhost_worker? 133 * Not sure it's worth it, it's straight-forward enough. */ 134 sock = rcu_dereference_check(vq->private_data, 1); 135 if (!sock) 136 return; 137 138 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 139 if (wmem >= sock->sk->sk_sndbuf) { 140 mutex_lock(&vq->mutex); 141 tx_poll_start(net, sock); 142 mutex_unlock(&vq->mutex); 143 return; 144 } 145 146 use_mm(net->dev.mm); 147 mutex_lock(&vq->mutex); 148 vhost_disable_notify(vq); 149 150 if (wmem < sock->sk->sk_sndbuf / 2) 151 tx_poll_stop(net); 152 hdr_size = vq->vhost_hlen; 153 154 for (;;) { 155 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 156 ARRAY_SIZE(vq->iov), 157 &out, &in, 158 NULL, NULL); 159 /* On error, stop handling until the next kick. */ 160 if (unlikely(head < 0)) 161 break; 162 /* Nothing new? Wait for eventfd to tell us they refilled. */ 163 if (head == vq->num) { 164 wmem = atomic_read(&sock->sk->sk_wmem_alloc); 165 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { 166 tx_poll_start(net, sock); 167 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); 168 break; 169 } 170 if (unlikely(vhost_enable_notify(vq))) { 171 vhost_disable_notify(vq); 172 continue; 173 } 174 break; 175 } 176 if (in) { 177 vq_err(vq, "Unexpected descriptor format for TX: " 178 "out %d, int %d\n", out, in); 179 break; 180 } 181 /* Skip header. TODO: support TSO. */ 182 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); 183 msg.msg_iovlen = out; 184 len = iov_length(vq->iov, out); 185 /* Sanity check */ 186 if (!len) { 187 vq_err(vq, "Unexpected header len for TX: " 188 "%zd expected %zd\n", 189 iov_length(vq->hdr, s), hdr_size); 190 break; 191 } 192 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 193 err = sock->ops->sendmsg(NULL, sock, &msg, len); 194 if (unlikely(err < 0)) { 195 vhost_discard_vq_desc(vq, 1); 196 tx_poll_start(net, sock); 197 break; 198 } 199 if (err != len) 200 pr_debug("Truncated TX packet: " 201 " len %d != %zd\n", err, len); 202 vhost_add_used_and_signal(&net->dev, vq, head, 0); 203 total_len += len; 204 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 205 vhost_poll_queue(&vq->poll); 206 break; 207 } 208 } 209 210 mutex_unlock(&vq->mutex); 211 unuse_mm(net->dev.mm); 212 } 213 214 static int peek_head_len(struct sock *sk) 215 { 216 struct sk_buff *head; 217 int len = 0; 218 219 lock_sock(sk); 220 head = skb_peek(&sk->sk_receive_queue); 221 if (head) 222 len = head->len; 223 release_sock(sk); 224 return len; 225 } 226 227 /* This is a multi-buffer version of vhost_get_desc, that works if 228 * vq has read descriptors only. 229 * @vq - the relevant virtqueue 230 * @datalen - data length we'll be reading 231 * @iovcount - returned count of io vectors we fill 232 * @log - vhost log 233 * @log_num - log offset 234 * returns number of buffer heads allocated, negative on error 235 */ 236 static int get_rx_bufs(struct vhost_virtqueue *vq, 237 struct vring_used_elem *heads, 238 int datalen, 239 unsigned *iovcount, 240 struct vhost_log *log, 241 unsigned *log_num) 242 { 243 unsigned int out, in; 244 int seg = 0; 245 int headcount = 0; 246 unsigned d; 247 int r, nlogs = 0; 248 249 while (datalen > 0) { 250 if (unlikely(seg >= UIO_MAXIOV)) { 251 r = -ENOBUFS; 252 goto err; 253 } 254 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, 255 ARRAY_SIZE(vq->iov) - seg, &out, 256 &in, log, log_num); 257 if (d == vq->num) { 258 r = 0; 259 goto err; 260 } 261 if (unlikely(out || in <= 0)) { 262 vq_err(vq, "unexpected descriptor format for RX: " 263 "out %d, in %d\n", out, in); 264 r = -EINVAL; 265 goto err; 266 } 267 if (unlikely(log)) { 268 nlogs += *log_num; 269 log += *log_num; 270 } 271 heads[headcount].id = d; 272 heads[headcount].len = iov_length(vq->iov + seg, in); 273 datalen -= heads[headcount].len; 274 ++headcount; 275 seg += in; 276 } 277 heads[headcount - 1].len += datalen; 278 *iovcount = seg; 279 if (unlikely(log)) 280 *log_num = nlogs; 281 return headcount; 282 err: 283 vhost_discard_vq_desc(vq, headcount); 284 return r; 285 } 286 287 /* Expects to be always run from workqueue - which acts as 288 * read-size critical section for our kind of RCU. */ 289 static void handle_rx_big(struct vhost_net *net) 290 { 291 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; 292 unsigned out, in, log, s; 293 int head; 294 struct vhost_log *vq_log; 295 struct msghdr msg = { 296 .msg_name = NULL, 297 .msg_namelen = 0, 298 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 299 .msg_controllen = 0, 300 .msg_iov = vq->iov, 301 .msg_flags = MSG_DONTWAIT, 302 }; 303 304 struct virtio_net_hdr hdr = { 305 .flags = 0, 306 .gso_type = VIRTIO_NET_HDR_GSO_NONE 307 }; 308 309 size_t len, total_len = 0; 310 int err; 311 size_t hdr_size; 312 struct socket *sock = rcu_dereference(vq->private_data); 313 if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) 314 return; 315 316 use_mm(net->dev.mm); 317 mutex_lock(&vq->mutex); 318 vhost_disable_notify(vq); 319 hdr_size = vq->vhost_hlen; 320 321 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 322 vq->log : NULL; 323 324 for (;;) { 325 head = vhost_get_vq_desc(&net->dev, vq, vq->iov, 326 ARRAY_SIZE(vq->iov), 327 &out, &in, 328 vq_log, &log); 329 /* On error, stop handling until the next kick. */ 330 if (unlikely(head < 0)) 331 break; 332 /* OK, now we need to know about added descriptors. */ 333 if (head == vq->num) { 334 if (unlikely(vhost_enable_notify(vq))) { 335 /* They have slipped one in as we were 336 * doing that: check again. */ 337 vhost_disable_notify(vq); 338 continue; 339 } 340 /* Nothing new? Wait for eventfd to tell us 341 * they refilled. */ 342 break; 343 } 344 /* We don't need to be notified again. */ 345 if (out) { 346 vq_err(vq, "Unexpected descriptor format for RX: " 347 "out %d, int %d\n", 348 out, in); 349 break; 350 } 351 /* Skip header. TODO: support TSO/mergeable rx buffers. */ 352 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in); 353 msg.msg_iovlen = in; 354 len = iov_length(vq->iov, in); 355 /* Sanity check */ 356 if (!len) { 357 vq_err(vq, "Unexpected header len for RX: " 358 "%zd expected %zd\n", 359 iov_length(vq->hdr, s), hdr_size); 360 break; 361 } 362 err = sock->ops->recvmsg(NULL, sock, &msg, 363 len, MSG_DONTWAIT | MSG_TRUNC); 364 /* TODO: Check specific error and bomb out unless EAGAIN? */ 365 if (err < 0) { 366 vhost_discard_vq_desc(vq, 1); 367 break; 368 } 369 /* TODO: Should check and handle checksum. */ 370 if (err > len) { 371 pr_debug("Discarded truncated rx packet: " 372 " len %d > %zd\n", err, len); 373 vhost_discard_vq_desc(vq, 1); 374 continue; 375 } 376 len = err; 377 err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size); 378 if (err) { 379 vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n", 380 vq->iov->iov_base, err); 381 break; 382 } 383 len += hdr_size; 384 vhost_add_used_and_signal(&net->dev, vq, head, len); 385 if (unlikely(vq_log)) 386 vhost_log_write(vq, vq_log, log, len); 387 total_len += len; 388 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 389 vhost_poll_queue(&vq->poll); 390 break; 391 } 392 } 393 394 mutex_unlock(&vq->mutex); 395 unuse_mm(net->dev.mm); 396 } 397 398 /* Expects to be always run from workqueue - which acts as 399 * read-size critical section for our kind of RCU. */ 400 static void handle_rx_mergeable(struct vhost_net *net) 401 { 402 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; 403 unsigned uninitialized_var(in), log; 404 struct vhost_log *vq_log; 405 struct msghdr msg = { 406 .msg_name = NULL, 407 .msg_namelen = 0, 408 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 409 .msg_controllen = 0, 410 .msg_iov = vq->iov, 411 .msg_flags = MSG_DONTWAIT, 412 }; 413 414 struct virtio_net_hdr_mrg_rxbuf hdr = { 415 .hdr.flags = 0, 416 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE 417 }; 418 419 size_t total_len = 0; 420 int err, headcount; 421 size_t vhost_hlen, sock_hlen; 422 size_t vhost_len, sock_len; 423 struct socket *sock = rcu_dereference(vq->private_data); 424 if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) 425 return; 426 427 use_mm(net->dev.mm); 428 mutex_lock(&vq->mutex); 429 vhost_disable_notify(vq); 430 vhost_hlen = vq->vhost_hlen; 431 sock_hlen = vq->sock_hlen; 432 433 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? 434 vq->log : NULL; 435 436 while ((sock_len = peek_head_len(sock->sk))) { 437 sock_len += sock_hlen; 438 vhost_len = sock_len + vhost_hlen; 439 headcount = get_rx_bufs(vq, vq->heads, vhost_len, 440 &in, vq_log, &log); 441 /* On error, stop handling until the next kick. */ 442 if (unlikely(headcount < 0)) 443 break; 444 /* OK, now we need to know about added descriptors. */ 445 if (!headcount) { 446 if (unlikely(vhost_enable_notify(vq))) { 447 /* They have slipped one in as we were 448 * doing that: check again. */ 449 vhost_disable_notify(vq); 450 continue; 451 } 452 /* Nothing new? Wait for eventfd to tell us 453 * they refilled. */ 454 break; 455 } 456 /* We don't need to be notified again. */ 457 if (unlikely((vhost_hlen))) 458 /* Skip header. TODO: support TSO. */ 459 move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in); 460 else 461 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: 462 * needed because sendmsg can modify msg_iov. */ 463 copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in); 464 msg.msg_iovlen = in; 465 err = sock->ops->recvmsg(NULL, sock, &msg, 466 sock_len, MSG_DONTWAIT | MSG_TRUNC); 467 /* Userspace might have consumed the packet meanwhile: 468 * it's not supposed to do this usually, but might be hard 469 * to prevent. Discard data we got (if any) and keep going. */ 470 if (unlikely(err != sock_len)) { 471 pr_debug("Discarded rx packet: " 472 " len %d, expected %zd\n", err, sock_len); 473 vhost_discard_vq_desc(vq, headcount); 474 continue; 475 } 476 if (unlikely(vhost_hlen) && 477 memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0, 478 vhost_hlen)) { 479 vq_err(vq, "Unable to write vnet_hdr at addr %p\n", 480 vq->iov->iov_base); 481 break; 482 } 483 /* TODO: Should check and handle checksum. */ 484 if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF) && 485 memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount, 486 offsetof(typeof(hdr), num_buffers), 487 sizeof hdr.num_buffers)) { 488 vq_err(vq, "Failed num_buffers write"); 489 vhost_discard_vq_desc(vq, headcount); 490 break; 491 } 492 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, 493 headcount); 494 if (unlikely(vq_log)) 495 vhost_log_write(vq, vq_log, log, vhost_len); 496 total_len += vhost_len; 497 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 498 vhost_poll_queue(&vq->poll); 499 break; 500 } 501 } 502 503 mutex_unlock(&vq->mutex); 504 unuse_mm(net->dev.mm); 505 } 506 507 static void handle_rx(struct vhost_net *net) 508 { 509 if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF)) 510 handle_rx_mergeable(net); 511 else 512 handle_rx_big(net); 513 } 514 515 static void handle_tx_kick(struct vhost_work *work) 516 { 517 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 518 poll.work); 519 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 520 521 handle_tx(net); 522 } 523 524 static void handle_rx_kick(struct vhost_work *work) 525 { 526 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 527 poll.work); 528 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 529 530 handle_rx(net); 531 } 532 533 static void handle_tx_net(struct vhost_work *work) 534 { 535 struct vhost_net *net = container_of(work, struct vhost_net, 536 poll[VHOST_NET_VQ_TX].work); 537 handle_tx(net); 538 } 539 540 static void handle_rx_net(struct vhost_work *work) 541 { 542 struct vhost_net *net = container_of(work, struct vhost_net, 543 poll[VHOST_NET_VQ_RX].work); 544 handle_rx(net); 545 } 546 547 static int vhost_net_open(struct inode *inode, struct file *f) 548 { 549 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); 550 struct vhost_dev *dev; 551 int r; 552 553 if (!n) 554 return -ENOMEM; 555 556 dev = &n->dev; 557 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; 558 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; 559 r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX); 560 if (r < 0) { 561 kfree(n); 562 return r; 563 } 564 565 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); 566 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); 567 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 568 569 f->private_data = n; 570 571 return 0; 572 } 573 574 static void vhost_net_disable_vq(struct vhost_net *n, 575 struct vhost_virtqueue *vq) 576 { 577 if (!vq->private_data) 578 return; 579 if (vq == n->vqs + VHOST_NET_VQ_TX) { 580 tx_poll_stop(n); 581 n->tx_poll_state = VHOST_NET_POLL_DISABLED; 582 } else 583 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); 584 } 585 586 static void vhost_net_enable_vq(struct vhost_net *n, 587 struct vhost_virtqueue *vq) 588 { 589 struct socket *sock; 590 591 sock = rcu_dereference_protected(vq->private_data, 592 lockdep_is_held(&vq->mutex)); 593 if (!sock) 594 return; 595 if (vq == n->vqs + VHOST_NET_VQ_TX) { 596 n->tx_poll_state = VHOST_NET_POLL_STOPPED; 597 tx_poll_start(n, sock); 598 } else 599 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); 600 } 601 602 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 603 struct vhost_virtqueue *vq) 604 { 605 struct socket *sock; 606 607 mutex_lock(&vq->mutex); 608 sock = rcu_dereference_protected(vq->private_data, 609 lockdep_is_held(&vq->mutex)); 610 vhost_net_disable_vq(n, vq); 611 rcu_assign_pointer(vq->private_data, NULL); 612 mutex_unlock(&vq->mutex); 613 return sock; 614 } 615 616 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 617 struct socket **rx_sock) 618 { 619 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); 620 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); 621 } 622 623 static void vhost_net_flush_vq(struct vhost_net *n, int index) 624 { 625 vhost_poll_flush(n->poll + index); 626 vhost_poll_flush(&n->dev.vqs[index].poll); 627 } 628 629 static void vhost_net_flush(struct vhost_net *n) 630 { 631 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 632 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 633 } 634 635 static int vhost_net_release(struct inode *inode, struct file *f) 636 { 637 struct vhost_net *n = f->private_data; 638 struct socket *tx_sock; 639 struct socket *rx_sock; 640 641 vhost_net_stop(n, &tx_sock, &rx_sock); 642 vhost_net_flush(n); 643 vhost_dev_cleanup(&n->dev); 644 if (tx_sock) 645 fput(tx_sock->file); 646 if (rx_sock) 647 fput(rx_sock->file); 648 /* We do an extra flush before freeing memory, 649 * since jobs can re-queue themselves. */ 650 vhost_net_flush(n); 651 kfree(n); 652 return 0; 653 } 654 655 static struct socket *get_raw_socket(int fd) 656 { 657 struct { 658 struct sockaddr_ll sa; 659 char buf[MAX_ADDR_LEN]; 660 } uaddr; 661 int uaddr_len = sizeof uaddr, r; 662 struct socket *sock = sockfd_lookup(fd, &r); 663 if (!sock) 664 return ERR_PTR(-ENOTSOCK); 665 666 /* Parameter checking */ 667 if (sock->sk->sk_type != SOCK_RAW) { 668 r = -ESOCKTNOSUPPORT; 669 goto err; 670 } 671 672 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 673 &uaddr_len, 0); 674 if (r) 675 goto err; 676 677 if (uaddr.sa.sll_family != AF_PACKET) { 678 r = -EPFNOSUPPORT; 679 goto err; 680 } 681 return sock; 682 err: 683 fput(sock->file); 684 return ERR_PTR(r); 685 } 686 687 static struct socket *get_tap_socket(int fd) 688 { 689 struct file *file = fget(fd); 690 struct socket *sock; 691 if (!file) 692 return ERR_PTR(-EBADF); 693 sock = tun_get_socket(file); 694 if (!IS_ERR(sock)) 695 return sock; 696 sock = macvtap_get_socket(file); 697 if (IS_ERR(sock)) 698 fput(file); 699 return sock; 700 } 701 702 static struct socket *get_socket(int fd) 703 { 704 struct socket *sock; 705 /* special case to disable backend */ 706 if (fd == -1) 707 return NULL; 708 sock = get_raw_socket(fd); 709 if (!IS_ERR(sock)) 710 return sock; 711 sock = get_tap_socket(fd); 712 if (!IS_ERR(sock)) 713 return sock; 714 return ERR_PTR(-ENOTSOCK); 715 } 716 717 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 718 { 719 struct socket *sock, *oldsock; 720 struct vhost_virtqueue *vq; 721 int r; 722 723 mutex_lock(&n->dev.mutex); 724 r = vhost_dev_check_owner(&n->dev); 725 if (r) 726 goto err; 727 728 if (index >= VHOST_NET_VQ_MAX) { 729 r = -ENOBUFS; 730 goto err; 731 } 732 vq = n->vqs + index; 733 mutex_lock(&vq->mutex); 734 735 /* Verify that ring has been setup correctly. */ 736 if (!vhost_vq_access_ok(vq)) { 737 r = -EFAULT; 738 goto err_vq; 739 } 740 sock = get_socket(fd); 741 if (IS_ERR(sock)) { 742 r = PTR_ERR(sock); 743 goto err_vq; 744 } 745 746 /* start polling new socket */ 747 oldsock = rcu_dereference_protected(vq->private_data, 748 lockdep_is_held(&vq->mutex)); 749 if (sock != oldsock) { 750 vhost_net_disable_vq(n, vq); 751 rcu_assign_pointer(vq->private_data, sock); 752 vhost_net_enable_vq(n, vq); 753 } 754 755 mutex_unlock(&vq->mutex); 756 757 if (oldsock) { 758 vhost_net_flush_vq(n, index); 759 fput(oldsock->file); 760 } 761 762 mutex_unlock(&n->dev.mutex); 763 return 0; 764 765 err_vq: 766 mutex_unlock(&vq->mutex); 767 err: 768 mutex_unlock(&n->dev.mutex); 769 return r; 770 } 771 772 static long vhost_net_reset_owner(struct vhost_net *n) 773 { 774 struct socket *tx_sock = NULL; 775 struct socket *rx_sock = NULL; 776 long err; 777 mutex_lock(&n->dev.mutex); 778 err = vhost_dev_check_owner(&n->dev); 779 if (err) 780 goto done; 781 vhost_net_stop(n, &tx_sock, &rx_sock); 782 vhost_net_flush(n); 783 err = vhost_dev_reset_owner(&n->dev); 784 done: 785 mutex_unlock(&n->dev.mutex); 786 if (tx_sock) 787 fput(tx_sock->file); 788 if (rx_sock) 789 fput(rx_sock->file); 790 return err; 791 } 792 793 static int vhost_net_set_features(struct vhost_net *n, u64 features) 794 { 795 size_t vhost_hlen, sock_hlen, hdr_len; 796 int i; 797 798 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? 799 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 800 sizeof(struct virtio_net_hdr); 801 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 802 /* vhost provides vnet_hdr */ 803 vhost_hlen = hdr_len; 804 sock_hlen = 0; 805 } else { 806 /* socket provides vnet_hdr */ 807 vhost_hlen = 0; 808 sock_hlen = hdr_len; 809 } 810 mutex_lock(&n->dev.mutex); 811 if ((features & (1 << VHOST_F_LOG_ALL)) && 812 !vhost_log_access_ok(&n->dev)) { 813 mutex_unlock(&n->dev.mutex); 814 return -EFAULT; 815 } 816 n->dev.acked_features = features; 817 smp_wmb(); 818 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 819 mutex_lock(&n->vqs[i].mutex); 820 n->vqs[i].vhost_hlen = vhost_hlen; 821 n->vqs[i].sock_hlen = sock_hlen; 822 mutex_unlock(&n->vqs[i].mutex); 823 } 824 vhost_net_flush(n); 825 mutex_unlock(&n->dev.mutex); 826 return 0; 827 } 828 829 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 830 unsigned long arg) 831 { 832 struct vhost_net *n = f->private_data; 833 void __user *argp = (void __user *)arg; 834 u64 __user *featurep = argp; 835 struct vhost_vring_file backend; 836 u64 features; 837 int r; 838 switch (ioctl) { 839 case VHOST_NET_SET_BACKEND: 840 if (copy_from_user(&backend, argp, sizeof backend)) 841 return -EFAULT; 842 return vhost_net_set_backend(n, backend.index, backend.fd); 843 case VHOST_GET_FEATURES: 844 features = VHOST_FEATURES; 845 if (copy_to_user(featurep, &features, sizeof features)) 846 return -EFAULT; 847 return 0; 848 case VHOST_SET_FEATURES: 849 if (copy_from_user(&features, featurep, sizeof features)) 850 return -EFAULT; 851 if (features & ~VHOST_FEATURES) 852 return -EOPNOTSUPP; 853 return vhost_net_set_features(n, features); 854 case VHOST_RESET_OWNER: 855 return vhost_net_reset_owner(n); 856 default: 857 mutex_lock(&n->dev.mutex); 858 r = vhost_dev_ioctl(&n->dev, ioctl, arg); 859 vhost_net_flush(n); 860 mutex_unlock(&n->dev.mutex); 861 return r; 862 } 863 } 864 865 #ifdef CONFIG_COMPAT 866 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 867 unsigned long arg) 868 { 869 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 870 } 871 #endif 872 873 static const struct file_operations vhost_net_fops = { 874 .owner = THIS_MODULE, 875 .release = vhost_net_release, 876 .unlocked_ioctl = vhost_net_ioctl, 877 #ifdef CONFIG_COMPAT 878 .compat_ioctl = vhost_net_compat_ioctl, 879 #endif 880 .open = vhost_net_open, 881 .llseek = noop_llseek, 882 }; 883 884 static struct miscdevice vhost_net_misc = { 885 MISC_DYNAMIC_MINOR, 886 "vhost-net", 887 &vhost_net_fops, 888 }; 889 890 static int vhost_net_init(void) 891 { 892 return misc_register(&vhost_net_misc); 893 } 894 module_init(vhost_net_init); 895 896 static void vhost_net_exit(void) 897 { 898 misc_deregister(&vhost_net_misc); 899 } 900 module_exit(vhost_net_exit); 901 902 MODULE_VERSION("0.0.1"); 903 MODULE_LICENSE("GPL v2"); 904 MODULE_AUTHOR("Michael S. Tsirkin"); 905 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 906