xref: /openbmc/qemu/net/socket.c (revision caf2e8de4ed056acad4fbdb6fe420d8124d38f11)
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/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     SocketReadState rs;
41     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
42     struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
43     IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
44     bool read_poll;               /* waiting to receive data? */
45     bool write_poll;              /* waiting to transmit data? */
46 } NetSocketState;
47 
48 static void net_socket_accept(void *opaque);
49 static void net_socket_writable(void *opaque);
50 
51 static void net_socket_update_fd_handler(NetSocketState *s)
52 {
53     qemu_set_fd_handler(s->fd,
54                         s->read_poll ? s->send_fn : NULL,
55                         s->write_poll ? net_socket_writable : NULL,
56                         s);
57 }
58 
59 static void net_socket_read_poll(NetSocketState *s, bool enable)
60 {
61     s->read_poll = enable;
62     net_socket_update_fd_handler(s);
63 }
64 
65 static void net_socket_write_poll(NetSocketState *s, bool enable)
66 {
67     s->write_poll = enable;
68     net_socket_update_fd_handler(s);
69 }
70 
71 static void net_socket_writable(void *opaque)
72 {
73     NetSocketState *s = opaque;
74 
75     net_socket_write_poll(s, false);
76 
77     qemu_flush_queued_packets(&s->nc);
78 }
79 
80 static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
81 {
82     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
83     uint32_t len = htonl(size);
84     struct iovec iov[] = {
85         {
86             .iov_base = &len,
87             .iov_len  = sizeof(len),
88         }, {
89             .iov_base = (void *)buf,
90             .iov_len  = size,
91         },
92     };
93     size_t remaining;
94     ssize_t ret;
95 
96     remaining = iov_size(iov, 2) - s->send_index;
97     ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
98 
99     if (ret == -1 && errno == EAGAIN) {
100         ret = 0; /* handled further down */
101     }
102     if (ret == -1) {
103         s->send_index = 0;
104         return -errno;
105     }
106     if (ret < (ssize_t)remaining) {
107         s->send_index += ret;
108         net_socket_write_poll(s, true);
109         return 0;
110     }
111     s->send_index = 0;
112     return size;
113 }
114 
115 static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf, size_t size)
116 {
117     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
118     ssize_t ret;
119 
120     ret = RETRY_ON_EINTR(
121         s->dgram_dst.sin_family != AF_UNIX ?
122             sendto(s->fd, buf, size, 0,
123                      (struct sockaddr *)&s->dgram_dst,
124                      sizeof(s->dgram_dst)) :
125             send(s->fd, buf, size, 0)
126     );
127 
128     if (ret == -1 && errno == EAGAIN) {
129         net_socket_write_poll(s, true);
130         return 0;
131     }
132     return ret;
133 }
134 
135 static void net_socket_send_completed(NetClientState *nc, ssize_t len)
136 {
137     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
138 
139     if (!s->read_poll) {
140         net_socket_read_poll(s, true);
141     }
142 }
143 
144 static void net_socket_rs_finalize(SocketReadState *rs)
145 {
146     NetSocketState *s = container_of(rs, NetSocketState, rs);
147 
148     if (qemu_send_packet_async(&s->nc, rs->buf,
149                                rs->packet_len,
150                                net_socket_send_completed) == 0) {
151         net_socket_read_poll(s, false);
152     }
153 }
154 
155 static void net_socket_send(void *opaque)
156 {
157     NetSocketState *s = opaque;
158     int size;
159     int ret;
160     QEMU_UNINITIALIZED uint8_t buf1[NET_BUFSIZE];
161     const uint8_t *buf;
162 
163     size = recv(s->fd, buf1, sizeof(buf1), 0);
164     if (size < 0) {
165         if (errno != EWOULDBLOCK)
166             goto eoc;
167     } else if (size == 0) {
168         /* end of connection */
169     eoc:
170         net_socket_read_poll(s, false);
171         net_socket_write_poll(s, false);
172         if (s->listen_fd != -1) {
173             qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
174         }
175         close(s->fd);
176 
177         s->fd = -1;
178         net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
179         s->nc.link_down = true;
180         qemu_set_info_str(&s->nc, "%s", "");
181 
182         return;
183     }
184     buf = buf1;
185 
186     ret = net_fill_rstate(&s->rs, buf, size);
187 
188     if (ret == -1) {
189         goto eoc;
190     }
191 }
192 
193 static void net_socket_send_dgram(void *opaque)
194 {
195     NetSocketState *s = opaque;
196     int size;
197 
198     size = recv(s->fd, s->rs.buf, sizeof(s->rs.buf), 0);
199     if (size < 0)
200         return;
201     if (size == 0) {
202         /* end of connection */
203         net_socket_read_poll(s, false);
204         net_socket_write_poll(s, false);
205         return;
206     }
207     if (qemu_send_packet_async(&s->nc, s->rs.buf, size,
208                                net_socket_send_completed) == 0) {
209         net_socket_read_poll(s, false);
210     }
211 }
212 
213 static int net_socket_mcast_create(struct sockaddr_in *mcastaddr,
214                                    struct in_addr *localaddr,
215                                    Error **errp)
216 {
217     struct ip_mreq imr;
218     int fd;
219     int val, ret;
220 #ifdef __OpenBSD__
221     unsigned char loop;
222 #else
223     int loop;
224 #endif
225 
226     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
227         error_setg(errp, "specified mcastaddr %s (0x%08x) "
228                    "does not contain a multicast address",
229                    inet_ntoa(mcastaddr->sin_addr),
230                    (int)ntohl(mcastaddr->sin_addr.s_addr));
231         return -1;
232     }
233 
234     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
235     if (fd < 0) {
236         error_setg_errno(errp, errno, "can't create datagram socket");
237         return -1;
238     }
239 
240     /* Allow multiple sockets to bind the same multicast ip and port by setting
241      * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should be set
242      * on windows. Use socket_set_fast_reuse otherwise as it sets SO_REUSEADDR
243      * only on posix systems.
244      */
245     val = 1;
246     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
247     if (ret < 0) {
248         error_setg_errno(errp, errno,
249                          "can't set socket option SO_REUSEADDR");
250         goto fail;
251     }
252 
253     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
254     if (ret < 0) {
255         error_setg_errno(errp, errno, "can't bind ip=%s to socket",
256                          inet_ntoa(mcastaddr->sin_addr));
257         goto fail;
258     }
259 
260     /* Add host to multicast group */
261     imr.imr_multiaddr = mcastaddr->sin_addr;
262     if (localaddr) {
263         imr.imr_interface = *localaddr;
264     } else {
265         imr.imr_interface.s_addr = htonl(INADDR_ANY);
266     }
267 
268     ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
269                      &imr, sizeof(struct ip_mreq));
270     if (ret < 0) {
271         error_setg_errno(errp, errno,
272                          "can't add socket to multicast group %s",
273                          inet_ntoa(imr.imr_multiaddr));
274         goto fail;
275     }
276 
277     /* Force mcast msgs to loopback (eg. several QEMUs in same host */
278     loop = 1;
279     ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
280                      &loop, sizeof(loop));
281     if (ret < 0) {
282         error_setg_errno(errp, errno,
283                          "can't force multicast message to loopback");
284         goto fail;
285     }
286 
287     /* If a bind address is given, only send packets from that address */
288     if (localaddr != NULL) {
289         ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
290                          localaddr, sizeof(*localaddr));
291         if (ret < 0) {
292             error_setg_errno(errp, errno,
293                              "can't set the default network send interface");
294             goto fail;
295         }
296     }
297 
298     if (!qemu_set_blocking(fd, false, errp)) {
299         goto fail;
300     }
301 
302     return fd;
303 fail:
304     if (fd >= 0)
305         close(fd);
306     return -1;
307 }
308 
309 static void net_socket_cleanup(NetClientState *nc)
310 {
311     NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
312     if (s->fd != -1) {
313         net_socket_read_poll(s, false);
314         net_socket_write_poll(s, false);
315         close(s->fd);
316         s->fd = -1;
317     }
318     if (s->listen_fd != -1) {
319         qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
320         close(s->listen_fd);
321         s->listen_fd = -1;
322     }
323 }
324 
325 static NetClientInfo net_dgram_socket_info = {
326     .type = NET_CLIENT_DRIVER_SOCKET,
327     .size = sizeof(NetSocketState),
328     .receive = net_socket_receive_dgram,
329     .cleanup = net_socket_cleanup,
330 };
331 
332 static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
333                                                 const char *model,
334                                                 const char *name,
335                                                 int fd, int is_connected,
336                                                 const char *mcast,
337                                                 Error **errp)
338 {
339     struct sockaddr_in saddr;
340     int newfd;
341     NetClientState *nc;
342     NetSocketState *s;
343     SocketAddress *sa;
344     SocketAddressType sa_type;
345 
346     sa = socket_local_address(fd, errp);
347     if (!sa) {
348         return NULL;
349     }
350     sa_type = sa->type;
351     qapi_free_SocketAddress(sa);
352 
353     /* fd passed: multicast: "learn" dgram_dst address from bound address and save it
354      * Because this may be "shared" socket from a "master" process, datagrams would be recv()
355      * by ONLY ONE process: we must "clone" this dgram socket --jjo
356      */
357 
358     if (is_connected && mcast != NULL) {
359             if (parse_host_port(&saddr, mcast, errp) < 0) {
360                 goto err;
361             }
362             /* must be bound */
363             if (saddr.sin_addr.s_addr == 0) {
364                 error_setg(errp, "can't setup multicast destination address");
365                 goto err;
366             }
367             /* clone dgram socket */
368             newfd = net_socket_mcast_create(&saddr, NULL, errp);
369             if (newfd < 0) {
370                 goto err;
371             }
372             /* clone newfd to fd, close newfd */
373             dup2(newfd, fd);
374             close(newfd);
375 
376     }
377 
378     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
379 
380     s = DO_UPCAST(NetSocketState, nc, nc);
381 
382     s->fd = fd;
383     s->listen_fd = -1;
384     s->send_fn = net_socket_send_dgram;
385     net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
386     net_socket_read_poll(s, true);
387 
388     /* mcast: save bound address as dst */
389     if (is_connected && mcast != NULL) {
390         s->dgram_dst = saddr;
391         qemu_set_info_str(nc, "socket: fd=%d (cloned mcast=%s:%d)", fd,
392                           inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
393     } else {
394         if (sa_type == SOCKET_ADDRESS_TYPE_UNIX) {
395             s->dgram_dst.sin_family = AF_UNIX;
396         }
397 
398         qemu_set_info_str(nc, "socket: fd=%d %s", fd,
399                           SocketAddressType_str(sa_type));
400     }
401 
402     return s;
403 
404 err:
405     close(fd);
406     return NULL;
407 }
408 
409 static void net_socket_connect(void *opaque)
410 {
411     NetSocketState *s = opaque;
412     s->send_fn = net_socket_send;
413     net_socket_read_poll(s, true);
414 }
415 
416 static NetClientInfo net_socket_info = {
417     .type = NET_CLIENT_DRIVER_SOCKET,
418     .size = sizeof(NetSocketState),
419     .receive = net_socket_receive,
420     .cleanup = net_socket_cleanup,
421 };
422 
423 static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
424                                                  const char *model,
425                                                  const char *name,
426                                                  int fd, int is_connected)
427 {
428     NetClientState *nc;
429     NetSocketState *s;
430 
431     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
432 
433     qemu_set_info_str(nc, "socket: fd=%d", fd);
434 
435     s = DO_UPCAST(NetSocketState, nc, nc);
436 
437     s->fd = fd;
438     s->listen_fd = -1;
439     net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
440 
441     /* Disable Nagle algorithm on TCP sockets to reduce latency */
442     socket_set_nodelay(fd);
443 
444     if (is_connected) {
445         net_socket_connect(s);
446     } else {
447         qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
448     }
449     return s;
450 }
451 
452 static int net_socket_fd_check(int fd, Error **errp)
453 {
454     int so_type, optlen = sizeof(so_type);
455 
456     if (getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
457         (socklen_t *)&optlen) < 0) {
458         error_setg(errp, "can't get socket option SO_TYPE");
459         return -1;
460     }
461     if (so_type != SOCK_DGRAM && so_type != SOCK_STREAM) {
462         error_setg(errp, "socket type=%d for fd=%d must be either"
463                    " SOCK_DGRAM or SOCK_STREAM", so_type, fd);
464         return -1;
465     }
466     return so_type;
467 }
468 
469 static void net_socket_accept(void *opaque)
470 {
471     NetSocketState *s = opaque;
472     struct sockaddr_in saddr;
473     socklen_t len;
474     int fd;
475 
476     for(;;) {
477         len = sizeof(saddr);
478         fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
479         if (fd < 0 && errno != EINTR) {
480             return;
481         } else if (fd >= 0) {
482             qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
483             break;
484         }
485     }
486 
487     s->fd = fd;
488     s->nc.link_down = false;
489     net_socket_connect(s);
490     qemu_set_info_str(&s->nc, "socket: connection from %s:%d",
491                       inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
492 }
493 
494 static int net_socket_listen_init(NetClientState *peer,
495                                   const char *model,
496                                   const char *name,
497                                   const char *host_str,
498                                   Error **errp)
499 {
500     NetClientState *nc;
501     NetSocketState *s;
502     struct sockaddr_in saddr;
503     int fd, ret;
504 
505     if (parse_host_port(&saddr, host_str, errp) < 0) {
506         return -1;
507     }
508 
509     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
510     if (fd < 0) {
511         error_setg_errno(errp, errno, "can't create stream socket");
512         return -1;
513     }
514     if (!qemu_set_blocking(fd, false, errp)) {
515         close(fd);
516         return -1;
517     }
518 
519     socket_set_fast_reuse(fd);
520 
521     ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
522     if (ret < 0) {
523         error_setg_errno(errp, errno, "can't bind ip=%s to socket",
524                          inet_ntoa(saddr.sin_addr));
525         close(fd);
526         return -1;
527     }
528     ret = listen(fd, 0);
529     if (ret < 0) {
530         error_setg_errno(errp, errno, "can't listen on socket");
531         close(fd);
532         return -1;
533     }
534 
535     nc = qemu_new_net_client(&net_socket_info, peer, model, name);
536     s = DO_UPCAST(NetSocketState, nc, nc);
537     s->fd = -1;
538     s->listen_fd = fd;
539     s->nc.link_down = true;
540     net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
541 
542     qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
543     return 0;
544 }
545 
546 static int net_socket_connect_init(NetClientState *peer,
547                                    const char *model,
548                                    const char *name,
549                                    const char *host_str,
550                                    Error **errp)
551 {
552     NetSocketState *s;
553     int fd, connected, ret;
554     struct sockaddr_in saddr;
555 
556     if (parse_host_port(&saddr, host_str, errp) < 0) {
557         return -1;
558     }
559 
560     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
561     if (fd < 0) {
562         error_setg_errno(errp, errno, "can't create stream socket");
563         return -1;
564     }
565     if (!qemu_set_blocking(fd, false, errp)) {
566         close(fd);
567         return -1;
568     }
569 
570     connected = 0;
571     for(;;) {
572         ret = connect(fd, (struct sockaddr *)&saddr, sizeof(saddr));
573         if (ret < 0) {
574             if (errno == EINTR || errno == EWOULDBLOCK) {
575                 /* continue */
576             } else if (errno == EINPROGRESS ||
577                        errno == EALREADY) {
578                 break;
579             } else {
580                 error_setg_errno(errp, errno, "can't connect socket");
581                 close(fd);
582                 return -1;
583             }
584         } else {
585             connected = 1;
586             break;
587         }
588     }
589     s = net_socket_fd_init_stream(peer, model, name, fd, connected);
590     if (!s) {
591         return -1;
592     }
593 
594     qemu_set_info_str(&s->nc, "socket: connect to %s:%d",
595                       inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
596     return 0;
597 }
598 
599 static int net_socket_mcast_init(NetClientState *peer,
600                                  const char *model,
601                                  const char *name,
602                                  const char *host_str,
603                                  const char *localaddr_str,
604                                  Error **errp)
605 {
606     NetSocketState *s;
607     int fd;
608     struct sockaddr_in saddr;
609     struct in_addr localaddr, *param_localaddr;
610 
611     if (parse_host_port(&saddr, host_str, errp) < 0) {
612         return -1;
613     }
614 
615     if (localaddr_str != NULL) {
616         if (inet_aton(localaddr_str, &localaddr) == 0) {
617             error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
618                        localaddr_str);
619             return -1;
620         }
621         param_localaddr = &localaddr;
622     } else {
623         param_localaddr = NULL;
624     }
625 
626     fd = net_socket_mcast_create(&saddr, param_localaddr, errp);
627     if (fd < 0) {
628         return -1;
629     }
630 
631     s = net_socket_fd_init_dgram(peer, model, name, fd, 0, NULL, errp);
632     if (!s) {
633         return -1;
634     }
635 
636     s->dgram_dst = saddr;
637 
638     qemu_set_info_str(&s->nc, "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                                  Error **errp)
650 {
651     NetSocketState *s;
652     int fd, ret;
653     struct sockaddr_in laddr, raddr;
654 
655     if (parse_host_port(&laddr, lhost, errp) < 0) {
656         return -1;
657     }
658 
659     if (parse_host_port(&raddr, rhost, errp) < 0) {
660         return -1;
661     }
662 
663     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
664     if (fd < 0) {
665         error_setg_errno(errp, errno, "can't create datagram socket");
666         return -1;
667     }
668 
669     ret = socket_set_fast_reuse(fd);
670     if (ret < 0) {
671         error_setg_errno(errp, errno,
672                          "can't set socket option SO_REUSEADDR");
673         close(fd);
674         return -1;
675     }
676     ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
677     if (ret < 0) {
678         error_setg_errno(errp, errno, "can't bind ip=%s to socket",
679                          inet_ntoa(laddr.sin_addr));
680         close(fd);
681         return -1;
682     }
683     if (!qemu_set_blocking(fd, false, errp)) {
684         close(fd);
685         return -1;
686     }
687 
688     s = net_socket_fd_init_dgram(peer, model, name, fd, 0, NULL, errp);
689     if (!s) {
690         return -1;
691     }
692 
693     s->dgram_dst = raddr;
694 
695     qemu_set_info_str(&s->nc, "socket: udp=%s:%d", inet_ntoa(raddr.sin_addr),
696                       ntohs(raddr.sin_port));
697     return 0;
698 }
699 
700 int net_init_socket(const Netdev *netdev, const char *name,
701                     NetClientState *peer, Error **errp)
702 {
703     const NetdevSocketOptions *sock;
704 
705     assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
706     sock = &netdev->u.socket;
707 
708     if (!!sock->fd + !!sock->listen + !!sock->connect + !!sock->mcast +
709         !!sock->udp != 1) {
710         error_setg(errp, "exactly one of listen=, connect=, mcast= or udp="
711                    " is required");
712         return -1;
713     }
714 
715     if (sock->localaddr && !sock->mcast && !sock->udp) {
716         error_setg(errp, "localaddr= is only valid with mcast= or udp=");
717         return -1;
718     }
719 
720     if (sock->fd) {
721         int fd, so_type;
722 
723         fd = monitor_fd_param(monitor_cur(), sock->fd, errp);
724         if (fd == -1) {
725             return -1;
726         }
727         so_type = net_socket_fd_check(fd, errp);
728         if (so_type < 0) {
729             return -1;
730         }
731         if (!qemu_set_blocking(fd, false, errp)) {
732             return -1;
733         }
734         switch (so_type) {
735         case SOCK_DGRAM:
736             if (!net_socket_fd_init_dgram(peer, "socket", name, fd, 1,
737                                           sock->mcast, errp)) {
738                 return -1;
739             }
740             break;
741         case SOCK_STREAM:
742             if (!net_socket_fd_init_stream(peer, "socket", name, fd, 1)) {
743                 return -1;
744             }
745             break;
746         }
747         return 0;
748     }
749 
750     if (sock->listen) {
751         if (net_socket_listen_init(peer, "socket", name, sock->listen, errp)
752             < 0) {
753             return -1;
754         }
755         return 0;
756     }
757 
758     if (sock->connect) {
759         if (net_socket_connect_init(peer, "socket", name, sock->connect, errp)
760             < 0) {
761             return -1;
762         }
763         return 0;
764     }
765 
766     if (sock->mcast) {
767         /* if sock->localaddr is missing, it has been initialized to "all bits
768          * zero" */
769         if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
770                                   sock->localaddr, errp) < 0) {
771             return -1;
772         }
773         return 0;
774     }
775 
776     assert(sock->udp);
777     if (!sock->localaddr) {
778         error_setg(errp, "localaddr= is mandatory with udp=");
779         return -1;
780     }
781     if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr,
782                             errp) < 0) {
783         return -1;
784     }
785     return 0;
786 }
787