[Excerpt-socket-Learning]socket listen for local IP (inaddr_any) and get local IP address

1, the server is not fixed IP listening, only monitoring the host any IP address: (the client specifies the local IP address, the server does not need to modify any IP address information) bzero (&adr_inet, sizeof (adr_inet)); adr_inet.sin_family = af_inet; ADR_INET.SIN_ADDR.S_ADDR = htonl (Inaddr_any); Adr_inet.sin_port = htons (port);
Note: The dual IP address of the host has not been processed, to be verified;
2, obtain the local IP address: (no TCP and UDP points)//Remove the local IP address struct sockaddr_in serv; Char serv_ip[20]; int serv_len = sizeof (serv); GetSockName (SOCKFD, struct sockaddr *) &serv, (socklen_t *) &serv_len); Inet_ntop (Af_inet, &serv.sin_addr, serv_ip, sizeof (SERV_IP)); printf ("Local address:%s\n", serv_ip);
3. Get local IP Address: (no TCP and UDP) Udp:recvlen = Recvfrom (sockfd, buf, sizeof (BUF), 0, (struct sockaddr *) &adr_clnt, (Socklen_ T *) &len); if (Recvlen < 0) {usleep); continue;} char* ClientIP = Inet_ntoa (ADR_CLNT.SIN_ADDR); Long ClientPort = Ntohs (Adr_clnt.sin_port);
Tcp:accept (Listener, (struct sockaddr *) &their_addr, &socklen); char* ClientIP = Inet_ntoa (THEIR_ADDR.SIN_ADDR); Long ClientPort = Ntohs (Their_addrt.sin_port);
Note: If a socket is bundled with inaddr_any, which means that the socket can be used with the address of any host, then getsockname () will not return any information about the host's IP address unless it calls connect () or accept (). Windows socket applications should not assume that IP addresses will change from Inaddr_any to other addresses unless sockets are connected. This is because for multiple host environments, the IP address used by the socket is not known unless the socket is connected.