NetKit - Making Sockets in C Easy!

Have you ever spent way too much time poring over man pages, network guides and textbooks trying to figure out the C socket library? Wondering what in the heck is the difference between a struct sockaddr, a struct addrinfo, a struct in_addr and a struct hostent? Why there's bind and connect and listen and accept and socket?

Meanwhile, your friend using python just gets to call socket or whatever, and be done with it! This library is meant to help with that. Too many times, I've found myself wanting to build something with sockets -- even something exceedingly simple -- and found myself having to go back to Beej's Network Guide (Beej has saved my ass many a time!) and figure this stuff out all over again. No longer! Now if you want to connect to www.google.com, you can just say:

connection_t *con = nk_connect_to("www.google.com", "80");

And if you want to make a listening server on port 7890, you can just say

connection_t *con = nk_listen_on("7890");

And if you want to accept a client on that port, you just call:

connection_t *incoming_con = nk_accept(con);

So you can write a hello, world! server in one line:

#include "../include/netkit.h"

int main(int argc, char const *argv[]) {
	nk_send(nk_accept(nk_listen_on("7890")), "hello, world!\r\n");
}

A connection_t pointer holds all of the relevant information - the file descriptor in use, the IP version (4 or 6), the IP address, the hostname and port (if set), and various options. There's even a convenient print function to display the info:

connection_t *con = nk_connect_to("www.github.com", "80");
if (con)
	nk_print_connection(con);

which prints:

Connection:
	Type: Client (seeking) type
	Version: IPV4
	IP address: 204.232.175.90
	Hostname: www.github.com
	Port: 80

There are also versions of send and recv, including a version of recv which breaks on a user-specified delimiter (such as \r\n). Likely to come later are ability to choose TCP or UDP, simple functions for parsing/constructing HTTP requests/responses, grabbing the content of web pages, and more. There may be asyncronous functionality (using libuv, for example) in the future as well.

Installation and Usage:

Note that I've only run this on Mac OS X so far, but it should work on any unix system. On windows, a savvy user might be able to hack it to work.

Run make from the main directory. This should put netkit.o in the /bin directory. To use it, include /include/netkit.h and link with /bin/netkit.o. To build the examples, run make in the examples directory.

Examples:

• one_liner_helloworld.c: Does what you expect it to do.
• mini_http.c: A slightly more fleshed-out version of the hello world server, sends it in (somewhat) properly formed HTTP and HTML format, and does a proper teardown of the connection (calling nk_close()). Also prints out the request it receives from a browser (or otherwise).
• connector.c: Connects to a specified server and port, sends a GET request and returns a response.
• netkit_telnet.c: A pretty crummy version of telnet, but barely functional. Uses threads.