net/socket.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25
  26 #include "net/net.h"
  27 #include "clients.h"
  28 #include "monitor/monitor.h"
  29 #include "qapi/error.h"
  30 #include "qemu-common.h"
  31 #include "qemu/error-report.h"
  32 #include "qemu/option.h"
  33 #include "qemu/sockets.h"
  34 #include "qemu/iov.h"
  35 #include "qemu/main-loop.h"
  36
  37 typedef struct NetSocketState {
  38     NetClientState nc;
  39     int listen_fd;
  40     int fd;
  41     SocketReadState rs;
  42     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
  43     struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
  44     IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
  45     bool read_poll;               /* waiting to receive data? */
  46     bool write_poll;              /* waiting to transmit data? */
  47 } NetSocketState;
  48
  49 static void net_socket_accept(void *opaque);
  50 static void net_socket_writable(void *opaque);
  51
  52 static void net_socket_update_fd_handler(NetSocketState *s)
  53 {
  54     qemu_set_fd_handler(s->fd,
  55                         s->read_poll ? s->send_fn : NULL,
  56                         s->write_poll ? net_socket_writable : NULL,
  57                         s);
  58 }
  59
  60 static void net_socket_read_poll(NetSocketState *s, bool enable)
  61 {
  62     s->read_poll = enable;
  63     net_socket_update_fd_handler(s);
  64 }
  65
  66 static void net_socket_write_poll(NetSocketState *s, bool enable)
  67 {
  68     s->write_poll = enable;
  69     net_socket_update_fd_handler(s);
  70 }
  71
  72 static void net_socket_writable(void *opaque)
  73 {
  74     NetSocketState *s = opaque;
  75
  76     net_socket_write_poll(s, false);
  77
  78     qemu_flush_queued_packets(&s->nc);
  79 }
  80
  81 static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
  82 {
  83     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
  84     uint32_t len = htonl(size);
  85     struct iovec iov[] = {
  86         {
  87             .iov_base = &len,
  88             .iov_len  = sizeof(len),
  89         }, {
  90             .iov_base = (void *)buf,
  91             .iov_len  = size,
  92         },
  93     };
  94     size_t remaining;
  95     ssize_t ret;
  96
  97     remaining = iov_size(iov, 2) - s->send_index;
  98     ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
  99
 100     if (ret == -1 && errno == EAGAIN) {
 101         ret = 0; /* handled further down */
 102     }
 103     if (ret == -1) {
 104         s->send_index = 0;
 105         return -errno;
 106     }
 107     if (ret < (ssize_t)remaining) {
 108         s->send_index += ret;
 109         net_socket_write_poll(s, true);
 110         return 0;
 111     }
 112     s->send_index = 0;
 113     return size;
 114 }
 115
 116 static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf, size_t size)
 117 {
 118     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
 119     ssize_t ret;
 120
 121     do {
 122         ret = qemu_sendto(s->fd, buf, size, 0,
 123                           (struct sockaddr *)&s->dgram_dst,
 124                           sizeof(s->dgram_dst));
 125     } while (ret == -1 && errno == EINTR);
 126
 127     if (ret == -1 && errno == EAGAIN) {
 128         net_socket_write_poll(s, true);
 129         return 0;
 130     }
 131     return ret;
 132 }
 133
 134 static void net_socket_send_completed(NetClientState *nc, ssize_t len)
 135 {
 136     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
 137
 138     if (!s->read_poll) {
 139         net_socket_read_poll(s, true);
 140     }
 141 }
 142
 143 static void net_socket_rs_finalize(SocketReadState *rs)
 144 {
 145     NetSocketState *s = container_of(rs, NetSocketState, rs);
 146
 147     if (qemu_send_packet_async(&s->nc, rs->buf,
 148                                rs->packet_len,
 149                                net_socket_send_completed) == 0) {
 150         net_socket_read_poll(s, false);
 151     }
 152 }
 153
 154 static void net_socket_send(void *opaque)
 155 {
 156     NetSocketState *s = opaque;
 157     int size;
 158     int ret;
 159     uint8_t buf1[NET_BUFSIZE];
 160     const uint8_t *buf;
 161
 162     size = qemu_recv(s->fd, buf1, sizeof(buf1), 0);
 163     if (size < 0) {
 164         if (errno != EWOULDBLOCK)
 165             goto eoc;
 166     } else if (size == 0) {
 167         /* end of connection */
 168     eoc:
 169         net_socket_read_poll(s, false);
 170         net_socket_write_poll(s, false);
 171         if (s->listen_fd != -1) {
 172             qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
 173         }
 174         closesocket(s->fd);
 175
 176         s->fd = -1;
 177         net_socket_rs_init(&s->rs, net_socket_rs_finalize);
 178         s->nc.link_down = true;
 179         memset(s->nc.info_str, 0, sizeof(s->nc.info_str));
 180
 181         return;
 182     }
 183     buf = buf1;
 184
 185     ret = net_fill_rstate(&s->rs, buf, size);
 186
 187     if (ret == -1) {
 188         goto eoc;
 189     }
 190 }
 191
 192 static void net_socket_send_dgram(void *opaque)
 193 {
 194     NetSocketState *s = opaque;
 195     int size;
 196
 197     size = qemu_recv(s->fd, s->rs.buf, sizeof(s->rs.buf), 0);
 198     if (size < 0)
 199         return;
 200     if (size == 0) {
 201         /* end of connection */
 202         net_socket_read_poll(s, false);
 203         net_socket_write_poll(s, false);
 204         return;
 205     }
 206     if (qemu_send_packet_async(&s->nc, s->rs.buf, size,
 207                                net_socket_send_completed) == 0) {
 208         net_socket_read_poll(s, false);
 209     }
 210 }
 211
 212 static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr *localaddr)
 213 {
 214     struct ip_mreq imr;
 215     int fd;
 216     int val, ret;
 217 #ifdef __OpenBSD__
 218     unsigned char loop;
 219 #else
 220     int loop;
 221 #endif
 222
 223     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
 224         fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) "
 225                 "does not contain a multicast address\n",
 226                 inet_ntoa(mcastaddr->sin_addr),
 227                 (int)ntohl(mcastaddr->sin_addr.s_addr));
 228         return -1;
 229
 230     }
 231     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
 232     if (fd < 0) {
 233         perror("socket(PF_INET, SOCK_DGRAM)");
 234         return -1;
 235     }
 236
 237     /* Allow multiple sockets to bind the same multicast ip and port by setting
 238      * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should be set
 239      * on windows. Use socket_set_fast_reuse otherwise as it sets SO_REUSEADDR
 240      * only on posix systems.
 241      */
 242     val = 1;
 243     ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 244     if (ret < 0) {
 245         perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
 246         goto fail;
 247     }
 248
 249     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
 250     if (ret < 0) {
 251         perror("bind");
 252         goto fail;
 253     }
 254
 255     /* Add host to multicast group */
 256     imr.imr_multiaddr = mcastaddr->sin_addr;
 257     if (localaddr) {
 258         imr.imr_interface = *localaddr;
 259     } else {
 260         imr.imr_interface.s_addr = htonl(INADDR_ANY);
 261     }
 262
 263     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 264                           &imr, sizeof(struct ip_mreq));
 265     if (ret < 0) {
 266         perror("setsockopt(IP_ADD_MEMBERSHIP)");
 267         goto fail;
 268     }
 269
 270     /* Force mcast msgs to loopback (eg. several QEMUs in same host */
 271     loop = 1;
 272     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
 273                           &loop, sizeof(loop));
 274     if (ret < 0) {
 275         perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
 276         goto fail;
 277     }
 278
 279     /* If a bind address is given, only send packets from that address */
 280     if (localaddr != NULL) {
 281         ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
 282                               localaddr, sizeof(*localaddr));
 283         if (ret < 0) {
 284             perror("setsockopt(IP_MULTICAST_IF)");
 285             goto fail;
 286         }
 287     }
 288
 289     qemu_set_nonblock(fd);
 290     return fd;
 291 fail:
 292     if (fd >= 0)
 293         closesocket(fd);
 294     return -1;
 295 }
 296
 297 static void net_socket_cleanup(NetClientState *nc)
 298 {
 299     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
 300     if (s->fd != -1) {
 301         net_socket_read_poll(s, false);
 302         net_socket_write_poll(s, false);
 303         close(s->fd);
 304         s->fd = -1;
 305     }
 306     if (s->listen_fd != -1) {
 307         qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
 308         closesocket(s->listen_fd);
 309         s->listen_fd = -1;
 310     }
 311 }
 312
 313 static NetClientInfo net_dgram_socket_info = {
 314     .type = NET_CLIENT_DRIVER_SOCKET,
 315     .size = sizeof(NetSocketState),
 316     .receive = net_socket_receive_dgram,
 317     .cleanup = net_socket_cleanup,
 318 };
 319
 320 static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
 321                                                 const char *model,
 322                                                 const char *name,
 323                                                 int fd, int is_connected)
 324 {
 325     struct sockaddr_in saddr;
 326     int newfd;
 327     socklen_t saddr_len = sizeof(saddr);
 328     NetClientState *nc;
 329     NetSocketState *s;
 330
 331     /* fd passed: multicast: "learn" dgram_dst address from bound address and save it
 332      * Because this may be "shared" socket from a "master" process, datagrams would be recv()
 333      * by ONLY ONE process: we must "clone" this dgram socket --jjo
 334      */
 335
 336     if (is_connected) {
 337         if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
 338             /* must be bound */
 339             if (saddr.sin_addr.s_addr == 0) {
 340                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
 341                         "cannot setup multicast dst addr\n", fd);
 342                 goto err;
 343             }
 344             /* clone dgram socket */
 345             newfd = net_socket_mcast_create(&saddr, NULL);
 346             if (newfd < 0) {
 347                 /* error already reported by net_socket_mcast_create() */
 348                 goto err;
 349             }
 350             /* clone newfd to fd, close newfd */
 351             dup2(newfd, fd);
 352             close(newfd);
 353
 354         } else {
 355             fprintf(stderr,
 356                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
 357                     fd, strerror(errno));
 358             goto err;
 359         }
 360     }
 361
 362     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
 363
 364     s = DO_UPCAST(NetSocketState, nc, nc);
 365
 366     s->fd = fd;
 367     s->listen_fd = -1;
 368     s->send_fn = net_socket_send_dgram;
 369     net_socket_rs_init(&s->rs, net_socket_rs_finalize);
 370     net_socket_read_poll(s, true);
 371
 372     /* mcast: save bound address as dst */
 373     if (is_connected) {
 374         s->dgram_dst = saddr;
 375         snprintf(nc->info_str, sizeof(nc->info_str),
 376                  "socket: fd=%d (cloned mcast=%s:%d)",
 377                  fd, inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 378     } else {
 379         snprintf(nc->info_str, sizeof(nc->info_str),
 380                  "socket: fd=%d", fd);
 381     }
 382
 383     return s;
 384
 385 err:
 386     closesocket(fd);
 387     return NULL;
 388 }
 389
 390 static void net_socket_connect(void *opaque)
 391 {
 392     NetSocketState *s = opaque;
 393     s->send_fn = net_socket_send;
 394     net_socket_read_poll(s, true);
 395 }
 396
 397 static NetClientInfo net_socket_info = {
 398     .type = NET_CLIENT_DRIVER_SOCKET,
 399     .size = sizeof(NetSocketState),
 400     .receive = net_socket_receive,
 401     .cleanup = net_socket_cleanup,
 402 };
 403
 404 static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
 405                                                  const char *model,
 406                                                  const char *name,
 407                                                  int fd, int is_connected)
 408 {
 409     NetClientState *nc;
 410     NetSocketState *s;
 411
 412     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
 413
 414     snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
 415
 416     s = DO_UPCAST(NetSocketState, nc, nc);
 417
 418     s->fd = fd;
 419     s->listen_fd = -1;
 420     net_socket_rs_init(&s->rs, net_socket_rs_finalize);
 421
 422     /* Disable Nagle algorithm on TCP sockets to reduce latency */
 423     socket_set_nodelay(fd);
 424
 425     if (is_connected) {
 426         net_socket_connect(s);
 427     } else {
 428         qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
 429     }
 430     return s;
 431 }
 432
 433 static NetSocketState *net_socket_fd_init(NetClientState *peer,
 434                                           const char *model, const char *name,
 435                                           int fd, int is_connected)
 436 {
 437     int so_type = -1, optlen=sizeof(so_type);
 438
 439     if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
 440         (socklen_t *)&optlen)< 0) {
 441         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
 442                 fd);
 443         closesocket(fd);
 444         return NULL;
 445     }
 446     switch(so_type) {
 447     case SOCK_DGRAM:
 448         return net_socket_fd_init_dgram(peer, model, name, fd, is_connected);
 449     case SOCK_STREAM:
 450         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
 451     default:
 452         /* who knows ... this could be a eg. a pty, do warn and continue as stream */
 453         fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
 454         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
 455     }
 456     return NULL;
 457 }
 458
 459 static void net_socket_accept(void *opaque)
 460 {
 461     NetSocketState *s = opaque;
 462     struct sockaddr_in saddr;
 463     socklen_t len;
 464     int fd;
 465
 466     for(;;) {
 467         len = sizeof(saddr);
 468         fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
 469         if (fd < 0 && errno != EINTR) {
 470             return;
 471         } else if (fd >= 0) {
 472             qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
 473             break;
 474         }
 475     }
 476
 477     s->fd = fd;
 478     s->nc.link_down = false;
 479     net_socket_connect(s);
 480     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 481              "socket: connection from %s:%d",
 482              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 483 }
 484
 485 static int net_socket_listen_init(NetClientState *peer,
 486                                   const char *model,
 487                                   const char *name,
 488                                   const char *host_str)
 489 {
 490     NetClientState *nc;
 491     NetSocketState *s;
 492     SocketAddress *saddr;
 493     int ret;
 494     Error *local_error = NULL;
 495
 496     saddr = socket_parse(host_str, &local_error);
 497     if (saddr == NULL) {
 498         error_report_err(local_error);
 499         return -1;
 500     }
 501
 502     ret = socket_listen(saddr, &local_error);
 503     if (ret < 0) {
 504         qapi_free_SocketAddress(saddr);
 505         error_report_err(local_error);
 506         return -1;
 507     }
 508
 509     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
 510     s = DO_UPCAST(NetSocketState, nc, nc);
 511     s->fd = -1;
 512     s->listen_fd = ret;
 513     s->nc.link_down = true;
 514
 515     qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
 516     qapi_free_SocketAddress(saddr);
 517     return 0;
 518 }
 519
 520 typedef struct {
 521     NetClientState *peer;
 522     SocketAddress *saddr;
 523     char *model;
 524     char *name;
 525 } socket_connect_data;
 526
 527 static void socket_connect_data_free(socket_connect_data *c)
 528 {
 529     qapi_free_SocketAddress(c->saddr);
 530     g_free(c->model);
 531     g_free(c->name);
 532     g_free(c);
 533 }
 534
 535 static void net_socket_connected(int fd, Error *err, void *opaque)
 536 {
 537     socket_connect_data *c = opaque;
 538     NetSocketState *s;
 539     char *addr_str = NULL;
 540     Error *local_error = NULL;
 541
 542     addr_str = socket_address_to_string(c->saddr, &local_error);
 543     if (addr_str == NULL) {
 544         error_report_err(local_error);
 545         closesocket(fd);
 546         goto end;
 547     }
 548
 549     s = net_socket_fd_init(c->peer, c->model, c->name, fd, true);
 550     if (!s) {
 551         closesocket(fd);
 552         goto end;
 553     }
 554
 555     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 556              "socket: connect to %s", addr_str);
 557
 558 end:
 559     g_free(addr_str);
 560     socket_connect_data_free(c);
 561 }
 562
 563 static int net_socket_connect_init(NetClientState *peer,
 564                                    const char *model,
 565                                    const char *name,
 566                                    const char *host_str)
 567 {
 568     socket_connect_data *c = g_new0(socket_connect_data, 1);
 569     int fd = -1;
 570     Error *local_error = NULL;
 571
 572     c->peer = peer;
 573     c->model = g_strdup(model);
 574     c->name = g_strdup(name);
 575     c->saddr = socket_parse(host_str, &local_error);
 576     if (c->saddr == NULL) {
 577         goto err;
 578     }
 579
 580     fd = socket_connect(c->saddr, &local_error, net_socket_connected, c);
 581     if (fd < 0) {
 582         goto err;
 583     }
 584
 585     return 0;
 586
 587 err:
 588     error_report_err(local_error);
 589     socket_connect_data_free(c);
 590     return -1;
 591 }
 592
 593 static int net_socket_mcast_init(NetClientState *peer,
 594                                  const char *model,
 595                                  const char *name,
 596                                  const char *host_str,
 597                                  const char *localaddr_str)
 598 {
 599     NetSocketState *s;
 600     int fd;
 601     struct sockaddr_in saddr;
 602     struct in_addr localaddr, *param_localaddr;
 603
 604     if (parse_host_port(&saddr, host_str) < 0)
 605         return -1;
 606
 607     if (localaddr_str != NULL) {
 608         if (inet_aton(localaddr_str, &localaddr) == 0)
 609             return -1;
 610         param_localaddr = &localaddr;
 611     } else {
 612         param_localaddr = NULL;
 613     }
 614
 615     fd = net_socket_mcast_create(&saddr, param_localaddr);
 616     if (fd < 0)
 617         return -1;
 618
 619     s = net_socket_fd_init(peer, model, name, fd, 0);
 620     if (!s)
 621         return -1;
 622
 623     s->dgram_dst = saddr;
 624
 625     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 626              "socket: mcast=%s:%d",
 627              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 628     return 0;
 629
 630 }
 631
 632 static int net_socket_udp_init(NetClientState *peer,
 633                                  const char *model,
 634                                  const char *name,
 635                                  const char *rhost,
 636                                  const char *lhost)
 637 {
 638     NetSocketState *s;
 639     int fd, ret;
 640     struct sockaddr_in laddr, raddr;
 641
 642     if (parse_host_port(&laddr, lhost) < 0) {
 643         return -1;
 644     }
 645
 646     if (parse_host_port(&raddr, rhost) < 0) {
 647         return -1;
 648     }
 649
 650     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
 651     if (fd < 0) {
 652         perror("socket(PF_INET, SOCK_DGRAM)");
 653         return -1;
 654     }
 655
 656     ret = socket_set_fast_reuse(fd);
 657     if (ret < 0) {
 658         closesocket(fd);
 659         return -1;
 660     }
 661     ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
 662     if (ret < 0) {
 663         perror("bind");
 664         closesocket(fd);
 665         return -1;
 666     }
 667     qemu_set_nonblock(fd);
 668
 669     s = net_socket_fd_init(peer, model, name, fd, 0);
 670     if (!s) {
 671         return -1;
 672     }
 673
 674     s->dgram_dst = raddr;
 675
 676     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 677              "socket: udp=%s:%d",
 678              inet_ntoa(raddr.sin_addr), ntohs(raddr.sin_port));
 679     return 0;
 680 }
 681
 682 int net_init_socket(const Netdev *netdev, const char *name,
 683                     NetClientState *peer, Error **errp)
 684 {
 685     /* FIXME error_setg(errp, ...) on failure */
 686     Error *err = NULL;
 687     const NetdevSocketOptions *sock;
 688
 689     assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
 690     sock = &netdev->u.socket;
 691
 692     if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
 693         sock->has_udp != 1) {
 694         error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
 695                      " is required");
 696         return -1;
 697     }
 698
 699     if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
 700         error_report("localaddr= is only valid with mcast= or udp=");
 701         return -1;
 702     }
 703
 704     if (sock->has_fd) {
 705         int fd;
 706
 707         fd = monitor_fd_param(cur_mon, sock->fd, &err);
 708         if (fd == -1) {
 709             error_report_err(err);
 710             return -1;
 711         }
 712         qemu_set_nonblock(fd);
 713         if (!net_socket_fd_init(peer, "socket", name, fd, 1)) {
 714             return -1;
 715         }
 716         return 0;
 717     }
 718
 719     if (sock->has_listen) {
 720         if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
 721             return -1;
 722         }
 723         return 0;
 724     }
 725
 726     if (sock->has_connect) {
 727         if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
 728             -1) {
 729             return -1;
 730         }
 731         return 0;
 732     }
 733
 734     if (sock->has_mcast) {
 735         /* if sock->localaddr is missing, it has been initialized to "all bits
 736          * zero" */
 737         if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
 738             sock->localaddr) == -1) {
 739             return -1;
 740         }
 741         return 0;
 742     }
 743
 744     assert(sock->has_udp);
 745     if (!sock->has_localaddr) {
 746         error_report("localaddr= is mandatory with udp=");
 747         return -1;
 748     }
 749     if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
 750         -1) {
 751         return -1;
 752     }
 753     return 0;
 754 }