Thread: how to implement ftp server C

I have to develop 1 FTP (simple) server in C.
What do i mean with simple?? I mean that FTP server has to support:

1. authentication (USER, PASS, PORT)
2. change directory (CD)
3. file listing (LIST)
4. file retrive (RETR)

I have just developed as "split part" the numbers 1-2-3-4 and i have to merge them into main.c. So no problem with them.
What i don't understand is how to "receive" communications from the client.
I mean how can implement what the client wants (USER, PASS, CD, LIST, RETR)?
I've read the rfc959 but i have not totally understood the communication between client and sever.
Summary:

1. client connect to server (so into the server this part is the socket "accept(..)"), right?
2. server send to client "you are connected" right?
3. client send to server user,password (file 1, auth.c but i don't know how to read when client send to the server the user and password request)
4. after successful login the server send file list (part 3, list.c, no problem)
5. the client send to the server the file it wants to download or the changedir command (again, how to read this info from client's request?)
6. i hope you have understand

PS: i'm on GNU/Linux

I suggest you first master how to send data back and forth through a TCP connection. implement a client and server where the client sends strings, the server receives them, prints them out and responds to the client. without trying to actually do anything with the commands. you could use the FTP commands and responses if you like, or just arbitrary data.

google 'linux tcp socket programming' and there are multiple hits that describe simple clients and servers.

Thanks