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 "config-host.h"
  25
  26 #include "net/net.h"
  27 #include "clients.h"
  28 #include "monitor/monitor.h"
  29 #include "qemu-common.h"
  30 #include "qemu/error-report.h"
  31 #include "qemu/option.h"
  32 #include "qemu/sockets.h"
  33 #include "qemu/iov.h"
  34 #include "qemu/main-loop.h"
  35
  36 typedef struct NetSocketState {
  37     NetClientState nc;
  38     int listen_fd;
  39     int fd;
  40     int state; /* 0 = getting length, 1 = getting data */
  41     unsigned int index;
  42     unsigned int packet_len;
  43     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
  44     uint8_t buf[NET_BUFSIZE];
  45     struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
  46     IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
  47     bool read_poll;               /* waiting to receive data? */
  48     bool write_poll;              /* waiting to transmit data? */
  49 } NetSocketState;
  50
  51 static void net_socket_accept(void *opaque);
  52 static void net_socket_writable(void *opaque);
  53
  54 /* Only read packets from socket when peer can receive them */
  55 static int net_socket_can_send(void *opaque)
  56 {
  57     NetSocketState *s = opaque;
  58
  59     return qemu_can_send_packet(&s->nc);
  60 }
  61
  62 static void net_socket_update_fd_handler(NetSocketState *s)
  63 {
  64     qemu_set_fd_handler2(s->fd,
  65                          s->read_poll  ? net_socket_can_send : NULL,
  66                          s->read_poll  ? s->send_fn : NULL,
  67                          s->write_poll ? net_socket_writable : NULL,
  68                          s);
  69 }
  70
  71 static void net_socket_read_poll(NetSocketState *s, bool enable)
  72 {
  73     s->read_poll = enable;
  74     net_socket_update_fd_handler(s);
  75 }
  76
  77 static void net_socket_write_poll(NetSocketState *s, bool enable)
  78 {
  79     s->write_poll = enable;
  80     net_socket_update_fd_handler(s);
  81 }
  82
  83 static void net_socket_writable(void *opaque)
  84 {
  85     NetSocketState *s = opaque;
  86
  87     net_socket_write_poll(s, false);
  88
  89     qemu_flush_queued_packets(&s->nc);
  90 }
  91
  92 static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
  93 {
  94     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
  95     uint32_t len = htonl(size);
  96     struct iovec iov[] = {
  97         {
  98             .iov_base = &len,
  99             .iov_len  = sizeof(len),
 100         }, {
 101             .iov_base = (void *)buf,
 102             .iov_len  = size,
 103         },
 104     };
 105     size_t remaining;
 106     ssize_t ret;
 107
 108     remaining = iov_size(iov, 2) - s->send_index;
 109     ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
 110
 111     if (ret == -1 && errno == EAGAIN) {
 112         ret = 0; /* handled further down */
 113     }
 114     if (ret == -1) {
 115         s->send_index = 0;
 116         return -errno;
 117     }
 118     if (ret < (ssize_t)remaining) {
 119         s->send_index += ret;
 120         net_socket_write_poll(s, true);
 121         return 0;
 122     }
 123     s->send_index = 0;
 124     return size;
 125 }
 126
 127 static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf, size_t size)
 128 {
 129     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
 130     ssize_t ret;
 131
 132     do {
 133         ret = qemu_sendto(s->fd, buf, size, 0,
 134                           (struct sockaddr *)&s->dgram_dst,
 135                           sizeof(s->dgram_dst));
 136     } while (ret == -1 && errno == EINTR);
 137
 138     if (ret == -1 && errno == EAGAIN) {
 139         net_socket_write_poll(s, true);
 140         return 0;
 141     }
 142     return ret;
 143 }
 144
 145 static void net_socket_send(void *opaque)
 146 {
 147     NetSocketState *s = opaque;
 148     int size, err;
 149     unsigned l;
 150     uint8_t buf1[NET_BUFSIZE];
 151     const uint8_t *buf;
 152
 153     size = qemu_recv(s->fd, buf1, sizeof(buf1), 0);
 154     if (size < 0) {
 155         err = socket_error();
 156         if (err != EWOULDBLOCK)
 157             goto eoc;
 158     } else if (size == 0) {
 159         /* end of connection */
 160     eoc:
 161         net_socket_read_poll(s, false);
 162         net_socket_write_poll(s, false);
 163         if (s->listen_fd != -1) {
 164             qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
 165         }
 166         closesocket(s->fd);
 167
 168         s->fd = -1;
 169         s->state = 0;
 170         s->index = 0;
 171         s->packet_len = 0;
 172         s->nc.link_down = true;
 173         memset(s->buf, 0, sizeof(s->buf));
 174         memset(s->nc.info_str, 0, sizeof(s->nc.info_str));
 175
 176         return;
 177     }
 178     buf = buf1;
 179     while (size > 0) {
 180         /* reassemble a packet from the network */
 181         switch(s->state) {
 182         case 0:
 183             l = 4 - s->index;
 184             if (l > size)
 185                 l = size;
 186             memcpy(s->buf + s->index, buf, l);
 187             buf += l;
 188             size -= l;
 189             s->index += l;
 190             if (s->index == 4) {
 191                 /* got length */
 192                 s->packet_len = ntohl(*(uint32_t *)s->buf);
 193                 s->index = 0;
 194                 s->state = 1;
 195             }
 196             break;
 197         case 1:
 198             l = s->packet_len - s->index;
 199             if (l > size)
 200                 l = size;
 201             if (s->index + l <= sizeof(s->buf)) {
 202                 memcpy(s->buf + s->index, buf, l);
 203             } else {
 204                 fprintf(stderr, "serious error: oversized packet received,"
 205                     "connection terminated.\n");
 206                 s->state = 0;
 207                 goto eoc;
 208             }
 209
 210             s->index += l;
 211             buf += l;
 212             size -= l;
 213             if (s->index >= s->packet_len) {
 214                 qemu_send_packet(&s->nc, s->buf, s->packet_len);
 215                 s->index = 0;
 216                 s->state = 0;
 217             }
 218             break;
 219         }
 220     }
 221 }
 222
 223 static void net_socket_send_dgram(void *opaque)
 224 {
 225     NetSocketState *s = opaque;
 226     int size;
 227
 228     size = qemu_recv(s->fd, s->buf, sizeof(s->buf), 0);
 229     if (size < 0)
 230         return;
 231     if (size == 0) {
 232         /* end of connection */
 233         net_socket_read_poll(s, false);
 234         net_socket_write_poll(s, false);
 235         return;
 236     }
 237     qemu_send_packet(&s->nc, s->buf, size);
 238 }
 239
 240 static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr *localaddr)
 241 {
 242     struct ip_mreq imr;
 243     int fd;
 244     int val, ret;
 245 #ifdef __OpenBSD__
 246     unsigned char loop;
 247 #else
 248     int loop;
 249 #endif
 250
 251     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
 252         fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) "
 253                 "does not contain a multicast address\n",
 254                 inet_ntoa(mcastaddr->sin_addr),
 255                 (int)ntohl(mcastaddr->sin_addr.s_addr));
 256         return -1;
 257
 258     }
 259     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
 260     if (fd < 0) {
 261         perror("socket(PF_INET, SOCK_DGRAM)");
 262         return -1;
 263     }
 264
 265     /* Allow multiple sockets to bind the same multicast ip and port by setting
 266      * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should be set
 267      * on windows. Use socket_set_fast_reuse otherwise as it sets SO_REUSEADDR
 268      * only on posix systems.
 269      */
 270     val = 1;
 271     ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 272     if (ret < 0) {
 273         perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
 274         goto fail;
 275     }
 276
 277     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
 278     if (ret < 0) {
 279         perror("bind");
 280         goto fail;
 281     }
 282
 283     /* Add host to multicast group */
 284     imr.imr_multiaddr = mcastaddr->sin_addr;
 285     if (localaddr) {
 286         imr.imr_interface = *localaddr;
 287     } else {
 288         imr.imr_interface.s_addr = htonl(INADDR_ANY);
 289     }
 290
 291     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 292                           &imr, sizeof(struct ip_mreq));
 293     if (ret < 0) {
 294         perror("setsockopt(IP_ADD_MEMBERSHIP)");
 295         goto fail;
 296     }
 297
 298     /* Force mcast msgs to loopback (eg. several QEMUs in same host */
 299     loop = 1;
 300     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
 301                           &loop, sizeof(loop));
 302     if (ret < 0) {
 303         perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
 304         goto fail;
 305     }
 306
 307     /* If a bind address is given, only send packets from that address */
 308     if (localaddr != NULL) {
 309         ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
 310                               localaddr, sizeof(*localaddr));
 311         if (ret < 0) {
 312             perror("setsockopt(IP_MULTICAST_IF)");
 313             goto fail;
 314         }
 315     }
 316
 317     qemu_set_nonblock(fd);
 318     return fd;
 319 fail:
 320     if (fd >= 0)
 321         closesocket(fd);
 322     return -1;
 323 }
 324
 325 static void net_socket_cleanup(NetClientState *nc)
 326 {
 327     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
 328     if (s->fd != -1) {
 329         net_socket_read_poll(s, false);
 330         net_socket_write_poll(s, false);
 331         close(s->fd);
 332         s->fd = -1;
 333     }
 334     if (s->listen_fd != -1) {
 335         qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
 336         closesocket(s->listen_fd);
 337         s->listen_fd = -1;
 338     }
 339 }
 340
 341 static NetClientInfo net_dgram_socket_info = {
 342     .type = NET_CLIENT_OPTIONS_KIND_SOCKET,
 343     .size = sizeof(NetSocketState),
 344     .receive = net_socket_receive_dgram,
 345     .cleanup = net_socket_cleanup,
 346 };
 347
 348 static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
 349                                                 const char *model,
 350                                                 const char *name,
 351                                                 int fd, int is_connected)
 352 {
 353     struct sockaddr_in saddr;
 354     int newfd;
 355     socklen_t saddr_len;
 356     NetClientState *nc;
 357     NetSocketState *s;
 358
 359     /* fd passed: multicast: "learn" dgram_dst address from bound address and save it
 360      * Because this may be "shared" socket from a "master" process, datagrams would be recv()
 361      * by ONLY ONE process: we must "clone" this dgram socket --jjo
 362      */
 363
 364     if (is_connected) {
 365         if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
 366             /* must be bound */
 367             if (saddr.sin_addr.s_addr == 0) {
 368                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
 369                         "cannot setup multicast dst addr\n", fd);
 370                 goto err;
 371             }
 372             /* clone dgram socket */
 373             newfd = net_socket_mcast_create(&saddr, NULL);
 374             if (newfd < 0) {
 375                 /* error already reported by net_socket_mcast_create() */
 376                 goto err;
 377             }
 378             /* clone newfd to fd, close newfd */
 379             dup2(newfd, fd);
 380             close(newfd);
 381
 382         } else {
 383             fprintf(stderr,
 384                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
 385                     fd, strerror(errno));
 386             goto err;
 387         }
 388     }
 389
 390     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
 391
 392     snprintf(nc->info_str, sizeof(nc->info_str),
 393             "socket: fd=%d (%s mcast=%s:%d)",
 394             fd, is_connected ? "cloned" : "",
 395             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 396
 397     s = DO_UPCAST(NetSocketState, nc, nc);
 398
 399     s->fd = fd;
 400     s->listen_fd = -1;
 401     s->send_fn = net_socket_send_dgram;
 402     net_socket_read_poll(s, true);
 403
 404     /* mcast: save bound address as dst */
 405     if (is_connected) {
 406         s->dgram_dst = saddr;
 407     }
 408
 409     return s;
 410
 411 err:
 412     closesocket(fd);
 413     return NULL;
 414 }
 415
 416 static void net_socket_connect(void *opaque)
 417 {
 418     NetSocketState *s = opaque;
 419     s->send_fn = net_socket_send;
 420     net_socket_read_poll(s, true);
 421 }
 422
 423 static NetClientInfo net_socket_info = {
 424     .type = NET_CLIENT_OPTIONS_KIND_SOCKET,
 425     .size = sizeof(NetSocketState),
 426     .receive = net_socket_receive,
 427     .cleanup = net_socket_cleanup,
 428 };
 429
 430 static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
 431                                                  const char *model,
 432                                                  const char *name,
 433                                                  int fd, int is_connected)
 434 {
 435     NetClientState *nc;
 436     NetSocketState *s;
 437
 438     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
 439
 440     snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
 441
 442     s = DO_UPCAST(NetSocketState, nc, nc);
 443
 444     s->fd = fd;
 445     s->listen_fd = -1;
 446
 447     /* Disable Nagle algorithm on TCP sockets to reduce latency */
 448     socket_set_nodelay(fd);
 449
 450     if (is_connected) {
 451         net_socket_connect(s);
 452     } else {
 453         qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
 454     }
 455     return s;
 456 }
 457
 458 static NetSocketState *net_socket_fd_init(NetClientState *peer,
 459                                           const char *model, const char *name,
 460                                           int fd, int is_connected)
 461 {
 462     int so_type = -1, optlen=sizeof(so_type);
 463
 464     if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
 465         (socklen_t *)&optlen)< 0) {
 466         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
 467                 fd);
 468         closesocket(fd);
 469         return NULL;
 470     }
 471     switch(so_type) {
 472     case SOCK_DGRAM:
 473         return net_socket_fd_init_dgram(peer, model, name, fd, is_connected);
 474     case SOCK_STREAM:
 475         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
 476     default:
 477         /* who knows ... this could be a eg. a pty, do warn and continue as stream */
 478         fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
 479         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
 480     }
 481     return NULL;
 482 }
 483
 484 static void net_socket_accept(void *opaque)
 485 {
 486     NetSocketState *s = opaque;
 487     struct sockaddr_in saddr;
 488     socklen_t len;
 489     int fd;
 490
 491     for(;;) {
 492         len = sizeof(saddr);
 493         fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
 494         if (fd < 0 && errno != EINTR) {
 495             return;
 496         } else if (fd >= 0) {
 497             qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
 498             break;
 499         }
 500     }
 501
 502     s->fd = fd;
 503     s->nc.link_down = false;
 504     net_socket_connect(s);
 505     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 506              "socket: connection from %s:%d",
 507              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 508 }
 509
 510 static int net_socket_listen_init(NetClientState *peer,
 511                                   const char *model,
 512                                   const char *name,
 513                                   const char *host_str)
 514 {
 515     NetClientState *nc;
 516     NetSocketState *s;
 517     struct sockaddr_in saddr;
 518     int fd, ret;
 519
 520     if (parse_host_port(&saddr, host_str) < 0)
 521         return -1;
 522
 523     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
 524     if (fd < 0) {
 525         perror("socket");
 526         return -1;
 527     }
 528     qemu_set_nonblock(fd);
 529
 530     socket_set_fast_reuse(fd);
 531
 532     ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
 533     if (ret < 0) {
 534         perror("bind");
 535         closesocket(fd);
 536         return -1;
 537     }
 538     ret = listen(fd, 0);
 539     if (ret < 0) {
 540         perror("listen");
 541         closesocket(fd);
 542         return -1;
 543     }
 544
 545     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
 546     s = DO_UPCAST(NetSocketState, nc, nc);
 547     s->fd = -1;
 548     s->listen_fd = fd;
 549     s->nc.link_down = true;
 550
 551     qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
 552     return 0;
 553 }
 554
 555 static int net_socket_connect_init(NetClientState *peer,
 556                                    const char *model,
 557                                    const char *name,
 558                                    const char *host_str)
 559 {
 560     NetSocketState *s;
 561     int fd, connected, ret, err;
 562     struct sockaddr_in saddr;
 563
 564     if (parse_host_port(&saddr, host_str) < 0)
 565         return -1;
 566
 567     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
 568     if (fd < 0) {
 569         perror("socket");
 570         return -1;
 571     }
 572     qemu_set_nonblock(fd);
 573
 574     connected = 0;
 575     for(;;) {
 576         ret = connect(fd, (struct sockaddr *)&saddr, sizeof(saddr));
 577         if (ret < 0) {
 578             err = socket_error();
 579             if (err == EINTR || err == EWOULDBLOCK) {
 580             } else if (err == EINPROGRESS) {
 581                 break;
 582 #ifdef _WIN32
 583             } else if (err == WSAEALREADY || err == WSAEINVAL) {
 584                 break;
 585 #endif
 586             } else {
 587                 perror("connect");
 588                 closesocket(fd);
 589                 return -1;
 590             }
 591         } else {
 592             connected = 1;
 593             break;
 594         }
 595     }
 596     s = net_socket_fd_init(peer, model, name, fd, connected);
 597     if (!s)
 598         return -1;
 599     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 600              "socket: connect to %s:%d",
 601              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 602     return 0;
 603 }
 604
 605 static int net_socket_mcast_init(NetClientState *peer,
 606                                  const char *model,
 607                                  const char *name,
 608                                  const char *host_str,
 609                                  const char *localaddr_str)
 610 {
 611     NetSocketState *s;
 612     int fd;
 613     struct sockaddr_in saddr;
 614     struct in_addr localaddr, *param_localaddr;
 615
 616     if (parse_host_port(&saddr, host_str) < 0)
 617         return -1;
 618
 619     if (localaddr_str != NULL) {
 620         if (inet_aton(localaddr_str, &localaddr) == 0)
 621             return -1;
 622         param_localaddr = &localaddr;
 623     } else {
 624         param_localaddr = NULL;
 625     }
 626
 627     fd = net_socket_mcast_create(&saddr, param_localaddr);
 628     if (fd < 0)
 629         return -1;
 630
 631     s = net_socket_fd_init(peer, model, name, fd, 0);
 632     if (!s)
 633         return -1;
 634
 635     s->dgram_dst = saddr;
 636
 637     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 638              "socket: mcast=%s:%d",
 639              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 640     return 0;
 641
 642 }
 643
 644 static int net_socket_udp_init(NetClientState *peer,
 645                                  const char *model,
 646                                  const char *name,
 647                                  const char *rhost,
 648                                  const char *lhost)
 649 {
 650     NetSocketState *s;
 651     int fd, ret;
 652     struct sockaddr_in laddr, raddr;
 653
 654     if (parse_host_port(&laddr, lhost) < 0) {
 655         return -1;
 656     }
 657
 658     if (parse_host_port(&raddr, rhost) < 0) {
 659         return -1;
 660     }
 661
 662     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
 663     if (fd < 0) {
 664         perror("socket(PF_INET, SOCK_DGRAM)");
 665         return -1;
 666     }
 667
 668     ret = socket_set_fast_reuse(fd);
 669     if (ret < 0) {
 670         closesocket(fd);
 671         return -1;
 672     }
 673     ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
 674     if (ret < 0) {
 675         perror("bind");
 676         closesocket(fd);
 677         return -1;
 678     }
 679     qemu_set_nonblock(fd);
 680
 681     s = net_socket_fd_init(peer, model, name, fd, 0);
 682     if (!s) {
 683         return -1;
 684     }
 685
 686     s->dgram_dst = raddr;
 687
 688     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 689              "socket: udp=%s:%d",
 690              inet_ntoa(raddr.sin_addr), ntohs(raddr.sin_port));
 691     return 0;
 692 }
 693
 694 int net_init_socket(const NetClientOptions *opts, const char *name,
 695                     NetClientState *peer)
 696 {
 697     const NetdevSocketOptions *sock;
 698
 699     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_SOCKET);
 700     sock = opts->socket;
 701
 702     if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
 703         sock->has_udp != 1) {
 704         error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
 705                      " is required");
 706         return -1;
 707     }
 708
 709     if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
 710         error_report("localaddr= is only valid with mcast= or udp=");
 711         return -1;
 712     }
 713
 714     if (sock->has_fd) {
 715         int fd;
 716
 717         fd = monitor_handle_fd_param(cur_mon, sock->fd);
 718         if (fd == -1) {
 719             return -1;
 720         }
 721         qemu_set_nonblock(fd);
 722         if (!net_socket_fd_init(peer, "socket", name, fd, 1)) {
 723             return -1;
 724         }
 725         return 0;
 726     }
 727
 728     if (sock->has_listen) {
 729         if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
 730             return -1;
 731         }
 732         return 0;
 733     }
 734
 735     if (sock->has_connect) {
 736         if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
 737             -1) {
 738             return -1;
 739         }
 740         return 0;
 741     }
 742
 743     if (sock->has_mcast) {
 744         /* if sock->localaddr is missing, it has been initialized to "all bits
 745          * zero" */
 746         if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
 747             sock->localaddr) == -1) {
 748             return -1;
 749         }
 750         return 0;
 751     }
 752
 753     assert(sock->has_udp);
 754     if (!sock->has_localaddr) {
 755         error_report("localaddr= is mandatory with udp=");
 756         return -1;
 757     }
 758     if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
 759         -1) {
 760         return -1;
 761     }
 762     return 0;
 763 }