More extraction of functionality

Extracting server and tty functions into separate headers.
Thread functions for new connections, tty data and client data
are also extracted and used as separate functional blocks.

client.h

@@ -1,6 +1,21 @@
-/* Handles communication with clients. */
+#pragma once
 
-#include <moxerver.h>
+/* Handles communication with a client. */
+
+#include <common.h>
+#include <netinet/in.h>
+
+#define USERNAME_LEN 32
+
+typedef struct
+{
+	int socket;							/* client socket */
+	struct sockaddr_in address;			/* client address information */
+	char ip_string[INET_ADDRSTRLEN];	/* client IP address as a string */
+	time_t last_active;					/* time of client's last activity in seconds from Epoch */
+	char username[USERNAME_LEN];		/* username for human identification */
+	char data[DATABUF_LEN];				/* buffer for data received from client */
+} client_t;
 
 /**
  * Closes a client connection.