Socket programming

receive steps server

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <netdb.h>
#include <string.h>
#include <netinet/in.h>

int main(int argc, char *argv[]) {
  // 1. determine a socket

  int sockid;
  sockid = socket(AF_INET, SOCK_STREAM, 0);

  struct sockaddr_in server;
  server.sin_addr.s_addr = inet_addr("127.0.0.1");
  server.sin_family = AF_INET;
  server.sin_port = 8080;

  // 2. bind to that socket

  int bind_status = bind(sockid, (struct sockaddr *)&server, sizeof(server));

  printf("status %d", bind_status);

  // 3. listen to that connection

  int queue_limit = 50;
  listen(sockid, queue_limit);

  // 4. accept incoming connections

  struct sockaddr client_addr;
  socklen_t size = sizeof(client_addr);
  int client_sockid = accept(sockid, (struct sockaddr *)&client_addr, &size);

  return 0;
}

socket configuration client

// a socket creates an endpoint for communication and returns a descriptor
// a socket's method signature is: socket(int domain, int type, int protocol);

// domain: selects the protocol family which should be used.
// type: specifies the semantics of communication (different for tcp and udp).
// protocol: specifies a protocol to be used with the socket.

#include <stdio.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/types.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
  int sockid;

  // AF_INET: address format is host and port number
  // SOCK_STREAM: this type provides sequenced, reliable, two-way connection based byte streams. (TCP connection)
  sockid = socket(AF_INET, SOCK_STREAM, 0);

  // connect(int socket, const struct sockaddr *address, socklen_t address_len);
  // socket: the socket which the connection will be made
  // address: the host which to connect to

  struct sockaddr_in server;

  // inet_addr() formats the server address from char to int
  server.sin_addr.s_addr = inet_addr("127.0.0.1");
  server.sin_family = AF_INET;
  // use htons if byte order for the server is different than byte order for the client (big vs little endian)
  server.sin_port = 8080;

  int connect_status = connect(sockid, (struct sockaddr *)&server, sizeof(server));
  printf("connect status %d", connect_status);

  return 0;
}