#include <stdio.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netdb.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#include <string.h>

#include <unistd.h>

#include <stdlib.h>

#define MYPORT "17" // the port users will be connecting to

#define BACKLOG 10 // how many pending connections queue will hold

int main(int argc, char **argv)

{

if (argc!=2)

{

printf("Usage: %s message\n", argv[0]);

return 1;

}

struct sockaddr_storage their_addr;

socklen_t addr_size;

struct addrinfo hints, *res;

int sockfd, new_fd;

memset(&hints, 0, sizeof hints);

hints.ai_family = AF_UNSPEC; // use IPv4 or IPv6, whichever

hints.ai_socktype = SOCK_STREAM;

hints.ai_flags = AI_PASSIVE; // fill in my IP for me

getaddrinfo(NULL, MYPORT, &hints, &res);

// make a socket, bind it, and listen on it:

sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);

if (bind(sockfd, res->ai_addr, res->ai_addrlen) != 0)

{

perror("Bind failed");

exit(1);

}

if (listen(sockfd, BACKLOG) != 0)

{

perror("Listen failed");

exit(1);

}

// now accept an incoming connection:

addr_size = sizeof their_addr;

while ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &addr_size))>-1){

send(new_fd, argv[1], strlen(argv[1]), 0);

send(new_fd, "\n", strlen("\n"), 0);

close(new_fd);

}

}