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Accepting incoming socket connections

Started by January 10, 2000 07:33 AM
3 comments, last by Yanroy 24 years, 11 months ago
No one in the multiplayer section would answer this the first time I asked, so here it is. I am making a MUD that uses winsock32. I know how to make a connection to a remote computer, but on the server side, how do I accept that connection? I know it has something to do with the listen() function, but where/how do I call it? Also, how do I make the socket(s) on the server bind to a port number? Another thing related to this is parsing the data sent and received by the sockets. On the client end, I have a very nice system for this, but as soon as it enters the Send() function (which I did not make), I have no idea what happens to it. How do I get it to come out on the server as it came out on the client? Thanks for you help in advance. www.trak.to/rdp

Yanroy@usa.com

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You are not a real programmer until you end all your sentences with semicolons; (c) 2000 ROAD Programming
You are unique. Just like everybody else.
"Mechanical engineers design weapons; civil engineers design targets."
"Sensitivity is adjustable, so you can set it to detect elephants and other small creatures." -- Product Description for a vibration sensor

Yanroy@usa.com

Well, for the server the general algorithm is: (assumes tcp)

1. Create the socket
2. Bind() to the address and port on the machine you want (hint- use INADDR_ANY for all ip addresses)
3. listen() on the socket.
4. when listen returns(if blocking), it has a connection waiting, so...
5. accept() it. accept will return a new socket to use in communications with the client.
6. Send & recv on the new socket.
7. closesocket()
8. start at the listen

NOTES: this is single threaded and can only handle one connection at a time, but shows the general gist of it. Also, I don''t have the reference in front for the function params.

If you need some more info let me know. I''m doing a client/server library so it''s fairly fresh in my mind.

--Joe
Joe
-flynboy
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That was the best answer I have gotten yet
I am making a MUD, so I *kinda* need to have multiple connections. Could you tell me how to do that? Thanks in advance.

www.trak.to/rdp

Yanroy@usa.com

--------------------

You are not a real programmer until you end all your sentences with semicolons; (c) 2000 ROAD Programming
You are unique. Just like everybody else.
"Mechanical engineers design weapons; civil engineers design targets."
"Sensitivity is adjustable, so you can set it to detect elephants and other small creatures." -- Product Description for a vibration sensor

Yanroy@usa.com

That''s where the interesting part is.
There are a few different ways to handle it depending on:
1. The OS you''re running under
2. The expected number of connections
3. and so on...

The easiest (to explain, not necessarily implement) is to create a new thread to handle each new client socket. So, after accepting the connection, start a new thread and pass the socket to it, then continue to listen() for more connections.

The other way to is to use non-blocking sockets and the select() function to see which socket is ready to receive data and or connections.

The system I am currently using uses a hybrid. I have a main thread that handles any connections and sending data to clients, and a second thread that uses select() to receive data back from the sockets.

Joe
Joe
-flynboy
The Berkeley Sockets API is portable across most operating systems. In order to handle multiple connections in that you code something like this:

struct sockaddr_in servaddr;

socket listenfd = socket(...);
bind(listenfd, ...);
listen(listenfd, ...);
FD_ZERO(&all_fd);
FD_SET(listenfd, &all_fd);
for (; {
nready = select(maxfd + 1, &all_fd, NULL, NULL, NULL, NULL);
if (FD_ISSET(listenfd, &all_fd) {
client_fd = accept(listenfd, ...)
/* spawn new thread or whatever to handle client */
}
}

With Winsock you can replace the select loop with WSAAsyncSelect. Then you assign a message and a message handler to WSAAsyncSelect.

In Winsock2 you can also use WSAEventSelect, which works by signaling on events rather than windows messages.

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