simple FTP server program using Sockets

//======================================================================================================================= //ACTIVE FTP SERVER Start-up Code for Assignment 1 //single threaded ftp server //This code gives parts of the answers away. //The connection is established by ignoring USER and PASS, but sending the appropriate 3 digit codes back //only the active FTP mode connection is implemented (watch out for firewall issues - do not block your own FTP server!). //The ftp LIST command is fully implemented, in a very naive way using redirection and a temporary file. //The list may have duplications, extra lines etc, don't worry about these. You can fix it as an exercise, //but no need to do that for the assignment. //In order to implement RETR you can use the LIST part as a startup. RETR carries a filename, //so you need to replace the name when opening the file to send. //STOR is also a few steps away, use your implementation of RETR and invert it to save the file on the server's dir //======================================================================================================================= #include <stdio.h style="box-sizing: border-box;">#include <string.h style="box-sizing: border-box;">#include <stdlib.h style="box-sizing: border-box;">#include <winsock.h style="box-sizing: border-box;">#include <winsock2.h style="box-sizing: border-box;">#define INET_ADDRSTRLEN 16 #define WSVERS MAKEWORD(2,0) WSADATA wsadata; //******************************************************************** //MAIN //******************************************************************** int main(int argc, char *argv[]) { //******************************************************************** // INITIALIZATION //******************************************************************** if (WSAStartup(WSVERS, &wsadata) == INVALID_SOCKET) { WSACleanup(); printf("WSAStartup failed\n"); } struct sockaddr_in localaddr,remoteaddr; struct sockaddr_in local_data_addr_act; SOCKET s,ns; SOCKET ns_data, s_data_act; char send_buffer[200],receive_buffer[200]; ...