cnet

An opinionated C package to provide a Golang net stdlib like experience

cnet is a C library to minimize the difficulty in writing network code with C. It provides simple primitives, and functions for reducing the overhead in writing network code. By being slightly opinionated cnet cuts down the amount of code one needs to write to setup network code (specify ip addresses, socket options, create socket, etc...) roughly 5x -> 10x.

details

Although C isn't tremendously difficult, writing network code in C is a process that I find to be excessively verbose. Compared to Go which you can create a network listener in less than 10 lines of code, accomplishing the same thing with C takes roughly 50 -> 150 lines of code. While it's not fair to expect C to be as simple to use as Go, part of this problem with verbosity is caused by there being no real C equivalent of Golang's stdlib net packet. By solving this, you can leverage modern C compiler niceness to create a usage experience that is only moderately more difficult to use than Go's net.

features

• fd_pool_t is a thread-safe wrapper around the FD_SET, FD_ISSET, select and other core data types
  • Enables managing a pool of tcp and/or udp sockets (set, clear, get, etc..)
  • Enables retrieving all available sockets for reading/writing
• socket management functions
  • listen on tcp/udp sockets
  • connect to tcp/udp sockets
  • control socket options (blocking, non-blocking, reuseaddr, etc..)

dependencies

To use cnet you only need two third-party dependencies, and a C11 compiler:

• pthread
  • practically availble anywhere
• ulog
  • small logging library contained within the deps/ulog folder of this repository

usage

Listen On tcp://127.0.0.1:5001 W/ Default Socket Options [Server]

Default socket options enables soreuseport and enables socket blocking

#include "sockets.h"

int main(void) {
  // included via sockets.h
  // enables a debug logger
  thread_logger *thl = new_thread_logger(true);
  // the returned fd is the file descriptor that can be used with this socket
  int fd = listen_socket(thl, "127.0.0.1", "5001", true, true, default_sock_opts, default_socket_opts_count);
  fd_pool_t *fpool = new_fd_pool_t(); // create the fd management pool
  set_fd_pool_t(fpool, fd, true); // set the opened file descriptor
  fd_set check_set; // will contain the available file descriptors
  int num_active = get_active_fd_pool_t(fpool, &check_set, true, true); // get all available tcp sockets for reading
  printf("found %i available sockets for reading", num_active); 
  // check_set will contain all available fd's (if any)
  clear_thread_logger(thl); // free up resources associated with thl
  close(fd); // close the opened socket
}

Listen On udp://127.0.0.1:5002 W/ Docket Socket Options [Server]

Default socket options enables soreuseport and enables socket blocking

#include "sockets.h"
#include "fd_pool.h"

int main(void) {
  // included via sockets.h
  // enables a debug logger
  thread_logger *thl = new_thread_logger(true);
  // the returned fd is the file descriptor that can be used with this socket
  int fd = listen_socket(thl, "127.0.0.1", "5002", false, true, default_sock_opts, default_socket_opts_count);
  fd_pool_t *fpool = new_fd_pool_t(); // create the fd management pool
  set_fd_pool_t(fpool, fd, true); // set the opened file descriptor
  fd_set check_set; // will contain the available file descriptors
  int num_active = get_active_fd_pool_t(fpool, &check_set, false, true); // get all available udp sockets for reading
  printf("found %i available sockets for reading", num_active); 
  // check_set will contain all available fd's (if any)
  clear_thread_logger(thl); // free up resources associated with thl
  close(fd); // close the opened socket
}

Connect To tcp://127.0.0.1:5001 [Client]

#include "sockets.h"

int main(void) {
  // included via sockets.h
  // enables a debug logger
  thread_logger *thl = new_thread_logger(true);
  socket_client_t *sock_client = new_client_socket(thl, "127.0.0.1", "5001", true, true);
  printf("client socket opened with fd %i\n", sock_client->socket_number); // print the opened file descriptor
  clear_thread_logger(thl); // free up resources associated with thl
  free_socket_client_t(sock_client); // will close the opened socket as well
}

Connect To udp://127.0.0.1:5002 [Client]

#include "sockets.h"

int main(void) {
  // included via sockets.h
  // enables a debug logger
  thread_logger *thl = new_thread_logger(true);
  socket_client_t *sock_client = new_client_socket(thl, "127.0.0.1", "5002", false, true);
  printf("client socket opened with fd %i\n", sock_client->socket_number); // print the opened file descriptor
  clear_thread_logger(thl); // free up resources associated with thl
  free_socket_client_t(sock_client); // will close the opened socket as well
}