hw/virtio-net.c

   1 /*
   2  * Virtio Network Device
   3  *
   4  * Copyright IBM, Corp. 2007
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "virtio.h"
  15 #include "net.h"
  16 #include "net/checksum.h"
  17 #include "net/tap.h"
  18 #include "qemu-error.h"
  19 #include "qemu-timer.h"
  20 #include "virtio-net.h"
  21 #include "vhost_net.h"
  22
  23 #define VIRTIO_NET_VM_VERSION    11
  24
  25 #define MAC_TABLE_ENTRIES    64
  26 #define MAX_VLAN    (1 << 12)   /* Per 802.1Q definition */
  27
  28 typedef struct VirtIONet
  29 {
  30     VirtIODevice vdev;
  31     uint8_t mac[ETH_ALEN];
  32     uint16_t status;
  33     VirtQueue *rx_vq;
  34     VirtQueue *tx_vq;
  35     VirtQueue *ctrl_vq;
  36     NICState *nic;
  37     QEMUTimer *tx_timer;
  38     int tx_timer_active;
  39     uint32_t has_vnet_hdr;
  40     uint8_t has_ufo;
  41     struct {
  42         VirtQueueElement elem;
  43         ssize_t len;
  44     } async_tx;
  45     int mergeable_rx_bufs;
  46     uint8_t promisc;
  47     uint8_t allmulti;
  48     uint8_t alluni;
  49     uint8_t nomulti;
  50     uint8_t nouni;
  51     uint8_t nobcast;
  52     uint8_t vhost_started;
  53     VMChangeStateEntry *vmstate;
  54     struct {
  55         int in_use;
  56         int first_multi;
  57         uint8_t multi_overflow;
  58         uint8_t uni_overflow;
  59         uint8_t *macs;
  60     } mac_table;
  61     uint32_t *vlans;
  62 } VirtIONet;
  63
  64 /* TODO
  65  * - we could suppress RX interrupt if we were so inclined.
  66  */
  67
  68 static VirtIONet *to_virtio_net(VirtIODevice *vdev)
  69 {
  70     return (VirtIONet *)vdev;
  71 }
  72
  73 static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
  74 {
  75     VirtIONet *n = to_virtio_net(vdev);
  76     struct virtio_net_config netcfg;
  77
  78     netcfg.status = n->status;
  79     memcpy(netcfg.mac, n->mac, ETH_ALEN);
  80     memcpy(config, &netcfg, sizeof(netcfg));
  81 }
  82
  83 static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)
  84 {
  85     VirtIONet *n = to_virtio_net(vdev);
  86     struct virtio_net_config netcfg;
  87
  88     memcpy(&netcfg, config, sizeof(netcfg));
  89
  90     if (memcmp(netcfg.mac, n->mac, ETH_ALEN)) {
  91         memcpy(n->mac, netcfg.mac, ETH_ALEN);
  92         qemu_format_nic_info_str(&n->nic->nc, n->mac);
  93     }
  94 }
  95
  96 static void virtio_net_set_link_status(VLANClientState *nc)
  97 {
  98     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
  99     uint16_t old_status = n->status;
 100
 101     if (nc->link_down)
 102         n->status &= ~VIRTIO_NET_S_LINK_UP;
 103     else
 104         n->status |= VIRTIO_NET_S_LINK_UP;
 105
 106     if (n->status != old_status)
 107         virtio_notify_config(&n->vdev);
 108 }
 109
 110 static void virtio_net_reset(VirtIODevice *vdev)
 111 {
 112     VirtIONet *n = to_virtio_net(vdev);
 113
 114     /* Reset back to compatibility mode */
 115     n->promisc = 1;
 116     n->allmulti = 0;
 117     n->alluni = 0;
 118     n->nomulti = 0;
 119     n->nouni = 0;
 120     n->nobcast = 0;
 121     if (n->vhost_started) {
 122         vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
 123         n->vhost_started = 0;
 124     }
 125
 126     /* Flush any MAC and VLAN filter table state */
 127     n->mac_table.in_use = 0;
 128     n->mac_table.first_multi = 0;
 129     n->mac_table.multi_overflow = 0;
 130     n->mac_table.uni_overflow = 0;
 131     memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
 132     memset(n->vlans, 0, MAX_VLAN >> 3);
 133 }
 134
 135 static int peer_has_vnet_hdr(VirtIONet *n)
 136 {
 137     if (!n->nic->nc.peer)
 138         return 0;
 139
 140     if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP)
 141         return 0;
 142
 143     n->has_vnet_hdr = tap_has_vnet_hdr(n->nic->nc.peer);
 144
 145     return n->has_vnet_hdr;
 146 }
 147
 148 static int peer_has_ufo(VirtIONet *n)
 149 {
 150     if (!peer_has_vnet_hdr(n))
 151         return 0;
 152
 153     n->has_ufo = tap_has_ufo(n->nic->nc.peer);
 154
 155     return n->has_ufo;
 156 }
 157
 158 static uint32_t virtio_net_get_features(VirtIODevice *vdev, uint32_t features)
 159 {
 160     VirtIONet *n = to_virtio_net(vdev);
 161
 162     features |= (1 << VIRTIO_NET_F_MAC);
 163
 164     if (peer_has_vnet_hdr(n)) {
 165         tap_using_vnet_hdr(n->nic->nc.peer, 1);
 166     } else {
 167         features &= ~(0x1 << VIRTIO_NET_F_CSUM);
 168         features &= ~(0x1 << VIRTIO_NET_F_HOST_TSO4);
 169         features &= ~(0x1 << VIRTIO_NET_F_HOST_TSO6);
 170         features &= ~(0x1 << VIRTIO_NET_F_HOST_ECN);
 171
 172         features &= ~(0x1 << VIRTIO_NET_F_GUEST_CSUM);
 173         features &= ~(0x1 << VIRTIO_NET_F_GUEST_TSO4);
 174         features &= ~(0x1 << VIRTIO_NET_F_GUEST_TSO6);
 175         features &= ~(0x1 << VIRTIO_NET_F_GUEST_ECN);
 176     }
 177
 178     if (!peer_has_vnet_hdr(n) || !peer_has_ufo(n)) {
 179         features &= ~(0x1 << VIRTIO_NET_F_GUEST_UFO);
 180         features &= ~(0x1 << VIRTIO_NET_F_HOST_UFO);
 181     }
 182
 183     if (!n->nic->nc.peer ||
 184         n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
 185         return features;
 186     }
 187     if (!tap_get_vhost_net(n->nic->nc.peer)) {
 188         return features;
 189     }
 190     return vhost_net_get_features(tap_get_vhost_net(n->nic->nc.peer), features);
 191 }
 192
 193 static uint32_t virtio_net_bad_features(VirtIODevice *vdev)
 194 {
 195     uint32_t features = 0;
 196
 197     /* Linux kernel 2.6.25.  It understood MAC (as everyone must),
 198      * but also these: */
 199     features |= (1 << VIRTIO_NET_F_MAC);
 200     features |= (1 << VIRTIO_NET_F_CSUM);
 201     features |= (1 << VIRTIO_NET_F_HOST_TSO4);
 202     features |= (1 << VIRTIO_NET_F_HOST_TSO6);
 203     features |= (1 << VIRTIO_NET_F_HOST_ECN);
 204
 205     return features;
 206 }
 207
 208 static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
 209 {
 210     VirtIONet *n = to_virtio_net(vdev);
 211
 212     n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));
 213
 214     if (n->has_vnet_hdr) {
 215         tap_set_offload(n->nic->nc.peer,
 216                         (features >> VIRTIO_NET_F_GUEST_CSUM) & 1,
 217                         (features >> VIRTIO_NET_F_GUEST_TSO4) & 1,
 218                         (features >> VIRTIO_NET_F_GUEST_TSO6) & 1,
 219                         (features >> VIRTIO_NET_F_GUEST_ECN)  & 1,
 220                         (features >> VIRTIO_NET_F_GUEST_UFO)  & 1);
 221     }
 222 }
 223
 224 static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd,
 225                                      VirtQueueElement *elem)
 226 {
 227     uint8_t on;
 228
 229     if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(on)) {
 230         fprintf(stderr, "virtio-net ctrl invalid rx mode command\n");
 231         exit(1);
 232     }
 233
 234     on = ldub_p(elem->out_sg[1].iov_base);
 235
 236     if (cmd == VIRTIO_NET_CTRL_RX_MODE_PROMISC)
 237         n->promisc = on;
 238     else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLMULTI)
 239         n->allmulti = on;
 240     else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLUNI)
 241         n->alluni = on;
 242     else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOMULTI)
 243         n->nomulti = on;
 244     else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOUNI)
 245         n->nouni = on;
 246     else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOBCAST)
 247         n->nobcast = on;
 248     else
 249         return VIRTIO_NET_ERR;
 250
 251     return VIRTIO_NET_OK;
 252 }
 253
 254 static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
 255                                  VirtQueueElement *elem)
 256 {
 257     struct virtio_net_ctrl_mac mac_data;
 258
 259     if (cmd != VIRTIO_NET_CTRL_MAC_TABLE_SET || elem->out_num != 3 ||
 260         elem->out_sg[1].iov_len < sizeof(mac_data) ||
 261         elem->out_sg[2].iov_len < sizeof(mac_data))
 262         return VIRTIO_NET_ERR;
 263
 264     n->mac_table.in_use = 0;
 265     n->mac_table.first_multi = 0;
 266     n->mac_table.uni_overflow = 0;
 267     n->mac_table.multi_overflow = 0;
 268     memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
 269
 270     mac_data.entries = ldl_le_p(elem->out_sg[1].iov_base);
 271
 272     if (sizeof(mac_data.entries) +
 273         (mac_data.entries * ETH_ALEN) > elem->out_sg[1].iov_len)
 274         return VIRTIO_NET_ERR;
 275
 276     if (mac_data.entries <= MAC_TABLE_ENTRIES) {
 277         memcpy(n->mac_table.macs, elem->out_sg[1].iov_base + sizeof(mac_data),
 278                mac_data.entries * ETH_ALEN);
 279         n->mac_table.in_use += mac_data.entries;
 280     } else {
 281         n->mac_table.uni_overflow = 1;
 282     }
 283
 284     n->mac_table.first_multi = n->mac_table.in_use;
 285
 286     mac_data.entries = ldl_le_p(elem->out_sg[2].iov_base);
 287
 288     if (sizeof(mac_data.entries) +
 289         (mac_data.entries * ETH_ALEN) > elem->out_sg[2].iov_len)
 290         return VIRTIO_NET_ERR;
 291
 292     if (mac_data.entries) {
 293         if (n->mac_table.in_use + mac_data.entries <= MAC_TABLE_ENTRIES) {
 294             memcpy(n->mac_table.macs + (n->mac_table.in_use * ETH_ALEN),
 295                    elem->out_sg[2].iov_base + sizeof(mac_data),
 296                    mac_data.entries * ETH_ALEN);
 297             n->mac_table.in_use += mac_data.entries;
 298         } else {
 299             n->mac_table.multi_overflow = 1;
 300         }
 301     }
 302
 303     return VIRTIO_NET_OK;
 304 }
 305
 306 static int virtio_net_handle_vlan_table(VirtIONet *n, uint8_t cmd,
 307                                         VirtQueueElement *elem)
 308 {
 309     uint16_t vid;
 310
 311     if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(vid)) {
 312         fprintf(stderr, "virtio-net ctrl invalid vlan command\n");
 313         return VIRTIO_NET_ERR;
 314     }
 315
 316     vid = lduw_le_p(elem->out_sg[1].iov_base);
 317
 318     if (vid >= MAX_VLAN)
 319         return VIRTIO_NET_ERR;
 320
 321     if (cmd == VIRTIO_NET_CTRL_VLAN_ADD)
 322         n->vlans[vid >> 5] |= (1U << (vid & 0x1f));
 323     else if (cmd == VIRTIO_NET_CTRL_VLAN_DEL)
 324         n->vlans[vid >> 5] &= ~(1U << (vid & 0x1f));
 325     else
 326         return VIRTIO_NET_ERR;
 327
 328     return VIRTIO_NET_OK;
 329 }
 330
 331 static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 332 {
 333     VirtIONet *n = to_virtio_net(vdev);
 334     struct virtio_net_ctrl_hdr ctrl;
 335     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
 336     VirtQueueElement elem;
 337
 338     while (virtqueue_pop(vq, &elem)) {
 339         if ((elem.in_num < 1) || (elem.out_num < 1)) {
 340             fprintf(stderr, "virtio-net ctrl missing headers\n");
 341             exit(1);
 342         }
 343
 344         if (elem.out_sg[0].iov_len < sizeof(ctrl) ||
 345             elem.in_sg[elem.in_num - 1].iov_len < sizeof(status)) {
 346             fprintf(stderr, "virtio-net ctrl header not in correct element\n");
 347             exit(1);
 348         }
 349
 350         ctrl.class = ldub_p(elem.out_sg[0].iov_base);
 351         ctrl.cmd = ldub_p(elem.out_sg[0].iov_base + sizeof(ctrl.class));
 352
 353         if (ctrl.class == VIRTIO_NET_CTRL_RX_MODE)
 354             status = virtio_net_handle_rx_mode(n, ctrl.cmd, &elem);
 355         else if (ctrl.class == VIRTIO_NET_CTRL_MAC)
 356             status = virtio_net_handle_mac(n, ctrl.cmd, &elem);
 357         else if (ctrl.class == VIRTIO_NET_CTRL_VLAN)
 358             status = virtio_net_handle_vlan_table(n, ctrl.cmd, &elem);
 359
 360         stb_p(elem.in_sg[elem.in_num - 1].iov_base, status);
 361
 362         virtqueue_push(vq, &elem, sizeof(status));
 363         virtio_notify(vdev, vq);
 364     }
 365 }
 366
 367 /* RX */
 368
 369 static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
 370 {
 371     VirtIONet *n = to_virtio_net(vdev);
 372
 373     qemu_flush_queued_packets(&n->nic->nc);
 374
 375     /* We now have RX buffers, signal to the IO thread to break out of the
 376      * select to re-poll the tap file descriptor */
 377     qemu_notify_event();
 378 }
 379
 380 static int virtio_net_can_receive(VLANClientState *nc)
 381 {
 382     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
 383
 384     if (!virtio_queue_ready(n->rx_vq) ||
 385         !(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
 386         return 0;
 387
 388     return 1;
 389 }
 390
 391 static int virtio_net_has_buffers(VirtIONet *n, int bufsize)
 392 {
 393     if (virtio_queue_empty(n->rx_vq) ||
 394         (n->mergeable_rx_bufs &&
 395          !virtqueue_avail_bytes(n->rx_vq, bufsize, 0))) {
 396         virtio_queue_set_notification(n->rx_vq, 1);
 397
 398         /* To avoid a race condition where the guest has made some buffers
 399          * available after the above check but before notification was
 400          * enabled, check for available buffers again.
 401          */
 402         if (virtio_queue_empty(n->rx_vq) ||
 403             (n->mergeable_rx_bufs &&
 404              !virtqueue_avail_bytes(n->rx_vq, bufsize, 0)))
 405             return 0;
 406     }
 407
 408     virtio_queue_set_notification(n->rx_vq, 0);
 409     return 1;
 410 }
 411
 412 /* dhclient uses AF_PACKET but doesn't pass auxdata to the kernel so
 413  * it never finds out that the packets don't have valid checksums.  This
 414  * causes dhclient to get upset.  Fedora's carried a patch for ages to
 415  * fix this with Xen but it hasn't appeared in an upstream release of
 416  * dhclient yet.
 417  *
 418  * To avoid breaking existing guests, we catch udp packets and add
 419  * checksums.  This is terrible but it's better than hacking the guest
 420  * kernels.
 421  *
 422  * N.B. if we introduce a zero-copy API, this operation is no longer free so
 423  * we should provide a mechanism to disable it to avoid polluting the host
 424  * cache.
 425  */
 426 static void work_around_broken_dhclient(struct virtio_net_hdr *hdr,
 427                                         const uint8_t *buf, size_t size)
 428 {
 429     if ((hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && /* missing csum */
 430         (size > 27 && size < 1500) && /* normal sized MTU */
 431         (buf[12] == 0x08 && buf[13] == 0x00) && /* ethertype == IPv4 */
 432         (buf[23] == 17) && /* ip.protocol == UDP */
 433         (buf[34] == 0 && buf[35] == 67)) { /* udp.srcport == bootps */
 434         /* FIXME this cast is evil */
 435         net_checksum_calculate((uint8_t *)buf, size);
 436         hdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM;
 437     }
 438 }
 439
 440 static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)
 441 {
 442     int offset, i;
 443
 444     offset = i = 0;
 445     while (offset < count && i < iovcnt) {
 446         int len = MIN(iov[i].iov_len, count - offset);
 447         memcpy(iov[i].iov_base, buf + offset, len);
 448         offset += len;
 449         i++;
 450     }
 451
 452     return offset;
 453 }
 454
 455 static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
 456                           const void *buf, size_t size, size_t hdr_len)
 457 {
 458     struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)iov[0].iov_base;
 459     int offset = 0;
 460
 461     hdr->flags = 0;
 462     hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 463
 464     if (n->has_vnet_hdr) {
 465         memcpy(hdr, buf, sizeof(*hdr));
 466         offset = sizeof(*hdr);
 467         work_around_broken_dhclient(hdr, buf + offset, size - offset);
 468     }
 469
 470     /* We only ever receive a struct virtio_net_hdr from the tapfd,
 471      * but we may be passing along a larger header to the guest.
 472      */
 473     iov[0].iov_base += hdr_len;
 474     iov[0].iov_len  -= hdr_len;
 475
 476     return offset;
 477 }
 478
 479 static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
 480 {
 481     static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 482     static const uint8_t vlan[] = {0x81, 0x00};
 483     uint8_t *ptr = (uint8_t *)buf;
 484     int i;
 485
 486     if (n->promisc)
 487         return 1;
 488
 489     if (n->has_vnet_hdr) {
 490         ptr += sizeof(struct virtio_net_hdr);
 491     }
 492
 493     if (!memcmp(&ptr[12], vlan, sizeof(vlan))) {
 494         int vid = be16_to_cpup((uint16_t *)(ptr + 14)) & 0xfff;
 495         if (!(n->vlans[vid >> 5] & (1U << (vid & 0x1f))))
 496             return 0;
 497     }
 498
 499     if (ptr[0] & 1) { // multicast
 500         if (!memcmp(ptr, bcast, sizeof(bcast))) {
 501             return !n->nobcast;
 502         } else if (n->nomulti) {
 503             return 0;
 504         } else if (n->allmulti || n->mac_table.multi_overflow) {
 505             return 1;
 506         }
 507
 508         for (i = n->mac_table.first_multi; i < n->mac_table.in_use; i++) {
 509             if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {
 510                 return 1;
 511             }
 512         }
 513     } else { // unicast
 514         if (n->nouni) {
 515             return 0;
 516         } else if (n->alluni || n->mac_table.uni_overflow) {
 517             return 1;
 518         } else if (!memcmp(ptr, n->mac, ETH_ALEN)) {
 519             return 1;
 520         }
 521
 522         for (i = 0; i < n->mac_table.first_multi; i++) {
 523             if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {
 524                 return 1;
 525             }
 526         }
 527     }
 528
 529     return 0;
 530 }
 531
 532 static ssize_t virtio_net_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
 533 {
 534     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
 535     struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;
 536     size_t hdr_len, offset, i;
 537
 538     if (!virtio_net_can_receive(&n->nic->nc))
 539         return -1;
 540
 541     if (!virtio_net_has_buffers(n, size))
 542         return 0;
 543
 544     if (!receive_filter(n, buf, size))
 545         return size;
 546
 547     /* hdr_len refers to the header we supply to the guest */
 548     hdr_len = n->mergeable_rx_bufs ?
 549         sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct virtio_net_hdr);
 550
 551     offset = i = 0;
 552
 553     while (offset < size) {
 554         VirtQueueElement elem;
 555         int len, total;
 556         struct iovec sg[VIRTQUEUE_MAX_SIZE];
 557
 558         total = 0;
 559
 560         if ((i != 0 && !n->mergeable_rx_bufs) ||
 561             virtqueue_pop(n->rx_vq, &elem) == 0) {
 562             if (i == 0)
 563                 return -1;
 564             fprintf(stderr, "virtio-net truncating packet\n");
 565             exit(1);
 566         }
 567
 568         if (elem.in_num < 1) {
 569             fprintf(stderr, "virtio-net receive queue contains no in buffers\n");
 570             exit(1);
 571         }
 572
 573         if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != hdr_len) {
 574             fprintf(stderr, "virtio-net header not in first element\n");
 575             exit(1);
 576         }
 577
 578         memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);
 579
 580         if (i == 0) {
 581             if (n->mergeable_rx_bufs)
 582                 mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;
 583
 584             offset += receive_header(n, sg, elem.in_num,
 585                                      buf + offset, size - offset, hdr_len);
 586             total += hdr_len;
 587         }
 588
 589         /* copy in packet.  ugh */
 590         len = iov_fill(sg, elem.in_num,
 591                        buf + offset, size - offset);
 592         total += len;
 593
 594         /* signal other side */
 595         virtqueue_fill(n->rx_vq, &elem, total, i++);
 596
 597         offset += len;
 598     }
 599
 600     if (mhdr)
 601         mhdr->num_buffers = i;
 602
 603     virtqueue_flush(n->rx_vq, i);
 604     virtio_notify(&n->vdev, n->rx_vq);
 605
 606     return size;
 607 }
 608
 609 static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq);
 610
 611 static void virtio_net_tx_complete(VLANClientState *nc, ssize_t len)
 612 {
 613     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
 614
 615     virtqueue_push(n->tx_vq, &n->async_tx.elem, n->async_tx.len);
 616     virtio_notify(&n->vdev, n->tx_vq);
 617
 618     n->async_tx.elem.out_num = n->async_tx.len = 0;
 619
 620     virtio_queue_set_notification(n->tx_vq, 1);
 621     virtio_net_flush_tx(n, n->tx_vq);
 622 }
 623
 624 /* TX */
 625 static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
 626 {
 627     VirtQueueElement elem;
 628
 629     if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
 630         return;
 631
 632     if (n->async_tx.elem.out_num) {
 633         virtio_queue_set_notification(n->tx_vq, 0);
 634         return;
 635     }
 636
 637     while (virtqueue_pop(vq, &elem)) {
 638         ssize_t ret, len = 0;
 639         unsigned int out_num = elem.out_num;
 640         struct iovec *out_sg = &elem.out_sg[0];
 641         unsigned hdr_len;
 642
 643         /* hdr_len refers to the header received from the guest */
 644         hdr_len = n->mergeable_rx_bufs ?
 645             sizeof(struct virtio_net_hdr_mrg_rxbuf) :
 646             sizeof(struct virtio_net_hdr);
 647
 648         if (out_num < 1 || out_sg->iov_len != hdr_len) {
 649             fprintf(stderr, "virtio-net header not in first element\n");
 650             exit(1);
 651         }
 652
 653         /* ignore the header if GSO is not supported */
 654         if (!n->has_vnet_hdr) {
 655             out_num--;
 656             out_sg++;
 657             len += hdr_len;
 658         } else if (n->mergeable_rx_bufs) {
 659             /* tapfd expects a struct virtio_net_hdr */
 660             hdr_len -= sizeof(struct virtio_net_hdr);
 661             out_sg->iov_len -= hdr_len;
 662             len += hdr_len;
 663         }
 664
 665         ret = qemu_sendv_packet_async(&n->nic->nc, out_sg, out_num,
 666                                       virtio_net_tx_complete);
 667         if (ret == 0) {
 668             virtio_queue_set_notification(n->tx_vq, 0);
 669             n->async_tx.elem = elem;
 670             n->async_tx.len  = len;
 671             return;
 672         }
 673
 674         len += ret;
 675
 676         virtqueue_push(vq, &elem, len);
 677         virtio_notify(&n->vdev, vq);
 678     }
 679 }
 680
 681 static void virtio_net_handle_tx(VirtIODevice *vdev, VirtQueue *vq)
 682 {
 683     VirtIONet *n = to_virtio_net(vdev);
 684
 685     if (n->tx_timer_active) {
 686         virtio_queue_set_notification(vq, 1);
 687         qemu_del_timer(n->tx_timer);
 688         n->tx_timer_active = 0;
 689         virtio_net_flush_tx(n, vq);
 690     } else {
 691         qemu_mod_timer(n->tx_timer,
 692                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
 693         n->tx_timer_active = 1;
 694         virtio_queue_set_notification(vq, 0);
 695     }
 696 }
 697
 698 static void virtio_net_tx_timer(void *opaque)
 699 {
 700     VirtIONet *n = opaque;
 701
 702     n->tx_timer_active = 0;
 703
 704     /* Just in case the driver is not ready on more */
 705     if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
 706         return;
 707
 708     virtio_queue_set_notification(n->tx_vq, 1);
 709     virtio_net_flush_tx(n, n->tx_vq);
 710 }
 711
 712 static void virtio_net_save(QEMUFile *f, void *opaque)
 713 {
 714     VirtIONet *n = opaque;
 715
 716     if (n->vhost_started) {
 717         /* TODO: should we really stop the backend?
 718          * If we don't, it might keep writing to memory. */
 719         vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
 720         n->vhost_started = 0;
 721     }
 722     virtio_save(&n->vdev, f);
 723
 724     qemu_put_buffer(f, n->mac, ETH_ALEN);
 725     qemu_put_be32(f, n->tx_timer_active);
 726     qemu_put_be32(f, n->mergeable_rx_bufs);
 727     qemu_put_be16(f, n->status);
 728     qemu_put_byte(f, n->promisc);
 729     qemu_put_byte(f, n->allmulti);
 730     qemu_put_be32(f, n->mac_table.in_use);
 731     qemu_put_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN);
 732     qemu_put_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
 733     qemu_put_be32(f, n->has_vnet_hdr);
 734     qemu_put_byte(f, n->mac_table.multi_overflow);
 735     qemu_put_byte(f, n->mac_table.uni_overflow);
 736     qemu_put_byte(f, n->alluni);
 737     qemu_put_byte(f, n->nomulti);
 738     qemu_put_byte(f, n->nouni);
 739     qemu_put_byte(f, n->nobcast);
 740     qemu_put_byte(f, n->has_ufo);
 741 }
 742
 743 static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
 744 {
 745     VirtIONet *n = opaque;
 746     int i;
 747
 748     if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)
 749         return -EINVAL;
 750
 751     virtio_load(&n->vdev, f);
 752
 753     qemu_get_buffer(f, n->mac, ETH_ALEN);
 754     n->tx_timer_active = qemu_get_be32(f);
 755     n->mergeable_rx_bufs = qemu_get_be32(f);
 756
 757     if (version_id >= 3)
 758         n->status = qemu_get_be16(f);
 759
 760     if (version_id >= 4) {
 761         if (version_id < 8) {
 762             n->promisc = qemu_get_be32(f);
 763             n->allmulti = qemu_get_be32(f);
 764         } else {
 765             n->promisc = qemu_get_byte(f);
 766             n->allmulti = qemu_get_byte(f);
 767         }
 768     }
 769
 770     if (version_id >= 5) {
 771         n->mac_table.in_use = qemu_get_be32(f);
 772         /* MAC_TABLE_ENTRIES may be different from the saved image */
 773         if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
 774             qemu_get_buffer(f, n->mac_table.macs,
 775                             n->mac_table.in_use * ETH_ALEN);
 776         } else if (n->mac_table.in_use) {
 777             qemu_fseek(f, n->mac_table.in_use * ETH_ALEN, SEEK_CUR);
 778             n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;
 779             n->mac_table.in_use = 0;
 780         }
 781     }
 782
 783     if (version_id >= 6)
 784         qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
 785
 786     if (version_id >= 7) {
 787         if (qemu_get_be32(f) && !peer_has_vnet_hdr(n)) {
 788             error_report("virtio-net: saved image requires vnet_hdr=on");
 789             return -1;
 790         }
 791
 792         if (n->has_vnet_hdr) {
 793             tap_using_vnet_hdr(n->nic->nc.peer, 1);
 794             tap_set_offload(n->nic->nc.peer,
 795                     (n->vdev.guest_features >> VIRTIO_NET_F_GUEST_CSUM) & 1,
 796                     (n->vdev.guest_features >> VIRTIO_NET_F_GUEST_TSO4) & 1,
 797                     (n->vdev.guest_features >> VIRTIO_NET_F_GUEST_TSO6) & 1,
 798                     (n->vdev.guest_features >> VIRTIO_NET_F_GUEST_ECN)  & 1,
 799                     (n->vdev.guest_features >> VIRTIO_NET_F_GUEST_UFO)  & 1);
 800         }
 801     }
 802
 803     if (version_id >= 9) {
 804         n->mac_table.multi_overflow = qemu_get_byte(f);
 805         n->mac_table.uni_overflow = qemu_get_byte(f);
 806     }
 807
 808     if (version_id >= 10) {
 809         n->alluni = qemu_get_byte(f);
 810         n->nomulti = qemu_get_byte(f);
 811         n->nouni = qemu_get_byte(f);
 812         n->nobcast = qemu_get_byte(f);
 813     }
 814
 815     if (version_id >= 11) {
 816         if (qemu_get_byte(f) && !peer_has_ufo(n)) {
 817             error_report("virtio-net: saved image requires TUN_F_UFO support");
 818             return -1;
 819         }
 820     }
 821
 822     /* Find the first multicast entry in the saved MAC filter */
 823     for (i = 0; i < n->mac_table.in_use; i++) {
 824         if (n->mac_table.macs[i * ETH_ALEN] & 1) {
 825             break;
 826         }
 827     }
 828     n->mac_table.first_multi = i;
 829
 830     if (n->tx_timer_active) {
 831         qemu_mod_timer(n->tx_timer,
 832                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);
 833     }
 834     return 0;
 835 }
 836
 837 static void virtio_net_cleanup(VLANClientState *nc)
 838 {
 839     VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
 840
 841     n->nic = NULL;
 842 }
 843
 844 static NetClientInfo net_virtio_info = {
 845     .type = NET_CLIENT_TYPE_NIC,
 846     .size = sizeof(NICState),
 847     .can_receive = virtio_net_can_receive,
 848     .receive = virtio_net_receive,
 849         .cleanup = virtio_net_cleanup,
 850     .link_status_changed = virtio_net_set_link_status,
 851 };
 852
 853 static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
 854 {
 855     VirtIONet *n = to_virtio_net(vdev);
 856     if (!n->nic->nc.peer) {
 857         return;
 858     }
 859     if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
 860         return;
 861     }
 862
 863     if (!tap_get_vhost_net(n->nic->nc.peer)) {
 864         return;
 865     }
 866     if (!!n->vhost_started == !!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
 867         return;
 868     }
 869     if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
 870         int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), vdev);
 871         if (r < 0) {
 872             fprintf(stderr, "unable to start vhost net: %d: "
 873                     "falling back on userspace virtio\n", -r);
 874         } else {
 875             n->vhost_started = 1;
 876         }
 877     } else {
 878         vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
 879         n->vhost_started = 0;
 880     }
 881 }
 882
 883 static void virtio_net_vmstate_change(void *opaque, int running, int reason)
 884 {
 885     VirtIONet *n = opaque;
 886     if (!running) {
 887         return;
 888     }
 889     /* This is called when vm is started, it will start vhost backend if
 890      * appropriate e.g. after migration. */
 891     virtio_net_set_status(&n->vdev, n->vdev.status);
 892 }
 893
 894 VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)
 895 {
 896     VirtIONet *n;
 897     static int virtio_net_id;
 898
 899     n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,
 900                                         sizeof(struct virtio_net_config),
 901                                         sizeof(VirtIONet));
 902
 903     n->vdev.get_config = virtio_net_get_config;
 904     n->vdev.set_config = virtio_net_set_config;
 905     n->vdev.get_features = virtio_net_get_features;
 906     n->vdev.set_features = virtio_net_set_features;
 907     n->vdev.bad_features = virtio_net_bad_features;
 908     n->vdev.reset = virtio_net_reset;
 909     n->vdev.set_status = virtio_net_set_status;
 910     n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
 911     n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);
 912     n->ctrl_vq = virtio_add_queue(&n->vdev, 64, virtio_net_handle_ctrl);
 913     qemu_macaddr_default_if_unset(&conf->macaddr);
 914     memcpy(&n->mac[0], &conf->macaddr, sizeof(n->mac));
 915     n->status = VIRTIO_NET_S_LINK_UP;
 916
 917     n->nic = qemu_new_nic(&net_virtio_info, conf, dev->info->name, dev->id, n);
 918
 919     qemu_format_nic_info_str(&n->nic->nc, conf->macaddr.a);
 920
 921     n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);
 922     n->tx_timer_active = 0;
 923     n->mergeable_rx_bufs = 0;
 924     n->promisc = 1; /* for compatibility */
 925
 926     n->mac_table.macs = qemu_mallocz(MAC_TABLE_ENTRIES * ETH_ALEN);
 927
 928     n->vlans = qemu_mallocz(MAX_VLAN >> 3);
 929
 930     register_savevm("virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,
 931                     virtio_net_save, virtio_net_load, n);
 932     n->vmstate = qemu_add_vm_change_state_handler(virtio_net_vmstate_change, n);
 933
 934     return &n->vdev;
 935 }
 936
 937 void virtio_net_exit(VirtIODevice *vdev)
 938 {
 939     VirtIONet *n = DO_UPCAST(VirtIONet, vdev, vdev);
 940     qemu_del_vm_change_state_handler(n->vmstate);
 941
 942     if (n->vhost_started) {
 943         vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
 944     }
 945
 946     qemu_purge_queued_packets(&n->nic->nc);
 947
 948     unregister_savevm("virtio-net", n);
 949
 950     qemu_free(n->mac_table.macs);
 951     qemu_free(n->vlans);
 952
 953     qemu_del_timer(n->tx_timer);
 954     qemu_free_timer(n->tx_timer);
 955
 956     virtio_cleanup(&n->vdev);
 957     qemu_del_vlan_client(&n->nic->nc);
 958 }