simple server example

simple_server.c

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


#define PORT 7890

int main(int argc, char** argv)
{
  int sockfd, new_sockfd;
  struct sockaddr_in host_addr, client_addr;
  socklen_t sin_size;
  int recv_length = 1, yes = 1;
  char buff[1024];
  memset(&buff, '\0', 1024);

  sockfd = socket(PF_INET, SOCK_STREAM, 0);
  if (sockfd == -1) perror("in socket\n");

  if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) perror("setting socket option SO_REUSEADDR\n");


  host_addr.sin_family = AF_INET;
  host_addr.sin_port = htons(PORT);
  host_addr.sin_addr.s_addr = 0;
  memset(&(host_addr.sin_zero), '\0', 8);

  if (bind(sockfd, (struct sockaddr*)&host_addr, sizeof(struct sockaddr)) == -1) perror("binding to socket\n");

  if (listen(sockfd, 5) == -1) perror("listening on socket\n");


  while(1)
    {
      sin_size = sizeof(struct sockaddr_in);
      new_sockfd = accept(sockfd, (struct sockaddr*)&client_addr, &sin_size);
      if (new_sockfd == -1) perror("accepting connection\n");
      printf("server got connection from  %s prot %d\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

      send(new_sockfd,"Hello world\n", 11, 0);
      recv_length = recv(new_sockfd, &buff, 1024, 0);

      while(recv_length > 0)
	{
	  printf("received %d bytes --> %s\n", recv_length, (char*)&buff);
	  memset(&buff, '\0', 1024);
	  recv_length = recv(new_sockfd, &buff, 1024, 0);
	}
      close(new_sockfd);
    }
  return 0;
}