Who is connect on Socket in C

c, linux, sockets

Solution

The `accept()` call gives you the remote address if you pass the address of a `struct sockaddr` as argument:

struct sockaddr_storage remoteAddr;
socklen_t remoteAddrLen = sizeof(remoteAddr);

sock.conn = accept(sock.socket, (struct sockaddr *)&remoteAddr, &remoteAddrLen);

You can then convert the remote address to a string with getnameinfo(), this works with both IPv4 and IPv6:

char host[NI_MAXHOST];
getnameinfo((struct sockaddr *)&remoteAddr, remoteAddrLen, host, sizeof(host), NULL, 0, NI_NUMERICHOST);

Problem

i'm write some program in client/server style. Now i'm developing the server side, and i open an socket. But, i need to know who is connected in my socket. What IP is connected. Because i need to put in logs who connect on server. So, my question is how can i do this in C? Using Linux. I try to use `getsockopt()` but don't work. And i'm new on network programming. Someone know how can i do this? Here is the code of my socket: ``` int init_socket() { /** Declara um socket */ Socket sock; /** Inicia o socket */ sock.socket = socket(AF_INET, SOCK_STREAM, 0); /** Seta zeros no sockaddr */ memset(&sock.server, 0, sizeof (sock.server)); /** E tambem no buffer */ memset(sock.buff, 0, sizeof (sock.buff)); /** Seta os valores do sockaddr */ sock.server.sin_family = AF_INET; sock.server.sin_addr.s_addr = htonl(INADDR_ANY); //sock.server.sin_port = htons(get_config_int(&conf, "monitor_port")); sock.server.sin_port = htons(2200); /** Chama o bind */ bind(sock.socket, (struct sockaddr*) &sock.server, sizeof (sock.server)); /* * É um socket blocante, então espera encher o buffer * Faz o listen */ if (listen(sock.socket, 2) == -1) { /** Deu falha na preparação para o accept, insere nos logs */ insert_log(FATAL, LOG_KERNEL, "Não foi possível iniciar o socket - event.c"); /** Retorna falha */ return INIT_SOCKET_FAILED; } /** Se chegar aqui, faz o accept, dentro de um loop infinito */ connect: while ((sock.conn = accept(sock.socket, (struct sockaddr*) NULL, NULL))) { printf("Recebi uma conexão, começando comunicação...\n"); /** Agora conn é um file descriptor, podemos ler e gravar nele */ while (1) { if (read(sock.conn, sock.buff, sizeof (sock.buff)) == 0) { close(sock.conn); printf("Pronto para outra conexão...\n"); goto connect; } printf("Eu Li isso do Buffer: %s", sock.buff); /** Limpa o buffer */ memset(sock.buff, 0, sizeof (sock.buff)); sleep(1); } } return INIT_SOCKET_SUCCESS; } ``` Thanks for help!

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