#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#define CON_NUM 10
#define MAX_IPV4_SIZE 15

int main(int argc, char** argv) {
    int sockfd, new_fd;
    struct addrinfo hints, *servinfo;
    struct sockaddr_in their_addr;
    socklen_t sin_size;
	char *buff = (char*)malloc(1024);
    char ip[MAX_IPV4_SIZE];
    int rc;
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;

	if (argc != 2) {
		printf("Usage : %s PORT\n", argv[0]);
		return -1;
	}

    if ((rc = getaddrinfo(NULL, argv[1], &hints, &servinfo)) != 0) {
		printf("Error at getaddrinfo() : %s\n", gai_strerror(rc));
        return 1;
    }
	
	if ((sockfd = socket(servinfo->ai_family, servinfo->ai_socktype, servinfo->ai_protocol)) == -1) {
		printf("Error at socket() : %s\n", strerror(errno));
		freeaddrinfo(servinfo);
		return 1;
	}
	
	if (bind(sockfd, servinfo->ai_addr, servinfo->ai_addrlen) == -1) {
		printf("Error at bind() : %s\n", strerror(errno));
		freeaddrinfo(servinfo);
		close(sockfd);
		return -1;
	}
	
    if (listen(sockfd, CON_NUM) == -1) {
		printf("Error at listen() : %s\n", strerror(errno));
		freeaddrinfo(servinfo);
		close(sockfd);
		return -1;
    }
	sin_size = sizeof their_addr;
    while(1) {
		new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
		if (new_fd == -1) {
			printf("Error at accept() : %s\n", strerror(errno));
			continue;
		}
		inet_ntop(their_addr.sin_family, (struct sockaddr*)&their_addr.sin_addr, ip, sizeof ip);
		printf("Got connection from %s\n", ip);
		int j = 1;
		while (1) {
			j = recv(new_fd, buff, 1024, 0);
			if ( j == 0 )
				break;
			if ( j  == -1 ) {
				printf("Error at recv() : %s\n", strerror(errno));
				freeaddrinfo(servinfo);
				close(sockfd);
				return -1;
			}
			printf("Recieved : %s\n", buff);
		}
	}
	freeaddrinfo(servinfo);
	close(sockfd);
	close(new_fd);
    return 0;
}