static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer, const char *model, const char *name, int fd, int is_connected) { struct sockaddr_in saddr; int newfd; socklen_t saddr_len; NetClientState *nc; NetSocketState *s; /* fd passed: multicast: "learn" dgram_dst address from bound address and save it * Because this may be "shared" socket from a "master" process, datagrams would be recv() * by ONLY ONE process: we must "clone" this dgram socket --jjo */ if (is_connected) { if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) { /* must be bound */ if (saddr.sin_addr.s_addr == 0) { fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, " "cannot setup multicast dst addr\n", fd); goto err; } /* clone dgram socket */ newfd = net_socket_mcast_create(&saddr, NULL); if (newfd < 0) { /* error already reported by net_socket_mcast_create() */ goto err; } /* clone newfd to fd, close newfd */ dup2(newfd, fd); close(newfd); } else { fprintf(stderr, "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n", fd, strerror(errno)); goto err; } } nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name); snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d (%s mcast=%s:%d)", fd, is_connected ? "cloned" : "", inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port)); s = DO_UPCAST(NetSocketState, nc, nc); s->fd = fd; s->listen_fd = -1; s->send_fn = net_socket_send_dgram; net_socket_read_poll(s, true); /* mcast: save bound address as dst */ if (is_connected) { s->dgram_dst = saddr; } return s; err: closesocket(fd); return NULL; }