scanner.c

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

void scanner(int port, char host[]);

int main(int argc, char **argv) {
	char host[100];
	char *p;
	int ports[10];
	int i = 0;
	int var;
	char tok[] = " ,";
	
	if (argc < 2) {
       fprintf(stderr,"[+]usage: %s <hostname> <port,port,port...>\n", argv[0]);
       exit(0);
    }
    
    p = strtok(argv[2], tok);
    strcpy(host, argv[1]);
	while(p != NULL) {
		sscanf(p, "%d", &var);
		ports[i++] = var;
		p = strtok(NULL, tok);
	}
	
	for(i=0; i<(sizeof(ports)/sizeof(ports[0]); i++) {
		fprintf(stdout, "\n[+]Testing port: %d\n", ports[i]);
		scanner(ports[i], host);
	}
	return 0;
}

void scanner(int port, char host[]) {

	int sock, n;
    struct hostent *server;
    struct sockaddr_in serv_addr;
    
    char buffer[4096];
	
    server = gethostbyname(host);
    
	sock = socket(AF_INET, SOCK_STREAM, 0);
	/* Edit the params of socket to scan UDP ports,
	 * should be pretty straight forward I suppose.
	 */
	 
	if(sock < 0) {
		fprintf(stderr, "[-]Error creating socket");
		return;
	}
	
	bzero((char *) &serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	// AF_UNIX for Unix style socket
	
	bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);
	serv_addr.sin_port = htons(port);
	
	n = connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
	sleep(2);
	if(n < 0) {
		fprintf(stderr, "[-]Error Connecting to port\n");
		return;
	}
	
	memset(buffer, 0, sizeof(buffer));
	strcpy(buffer, "garbage\r\n");
	
	n = write(sock, buffer, strlen(buffer));
	if(n < 0) {
		fprintf(stderr, "[-]Error writing (Port closed maybe?!)\n");
		return;
	}
	
	bzero(buffer, 4096);
	n = read(sock, buffer, 4096);
	if(n < 0) {
		fprintf(stderr, "[-]Error reading (Port closed maybe?!)\n");
		return;
	}
	
	fprintf(stdout,"[*]%s\n", buffer);
	close(sock);
	   
}