check port socket

/************************************************************************* * File : test-port-client.c * Author : Saurabh Gupta * Desc : port read client * Note : This is a port-read client. It will accept any IP address and port * number on the commandline, connect to the server, send the message * (if any defined), read the reply, and close. * Source : http://www.ccplusplus.com/2011/07/socket.html * Created : 8:09 PM Friday, February 17, 2012 *************************************************************************/ #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/socket.h> #include <sys/un.h> #include <netinet/in.h> #define MAXBUF 1024 int main(int Count, char *Strings[]) { int sockfd, bytes_read; struct sockaddr_in dest; char buffer[MAXBUF]; /* * Make sure we have the right number of parameters */ if ( Count < 3 || Count > 4 ) { fprintf(stderr, "usage: %s <IP-addr> <port> [<send-msg>]\n", Strings[0]); exit(0); } /* * Create socket for streaming */ if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) { perror("Socket"); exit(errno); } /* * Initialize server address/port struct */ bzero(&dest, sizeof(dest)); dest.sin_family = AF_INET; if ( inet_addr(Strings[1], &dest.sin_addr.s_addr) == 0 ) { perror(Strings[1]); exit(errno); } dest.sin_port = htons(atoi(Strings[2])); /* * Connect to server */ if ( connect(sockfd, (struct sockaddr *)&dest, sizeof(dest)) != 0 ) { perror("Connect"); exit(errno); } /* * To send message to server, send with a '\n' (newline) */ if ( Count == 4 ) { sprintf(buffer, "%s\n", Strings[3]); send(sockfd, buffer, strlen(buffer), 0); } /* * While there's data, read and print it */ do { bzero(buffer, MAXBUF); bytes_read = recv(sockfd, buffer, MAXBUF, 0); if ( bytes_read > 0 ) printf("%s", buffer); } while ( bytes_read > 0 ); /* * Clean up */ close(sockfd); return 0; }