[C++] A Simple but Effective Port Scanner

[Gonzalez]

/**************************************
//* * *
// ****** A Simple but effective port sca
//* * *nner
// Description:This port scanner is pret
//* * *ty simple, it just fork()'s each connect
//* * *() call, and reads the return value.

/* simple connect port scanner.. -- very fast .. very detectable... */
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <netdb.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/poll.h>
static int verbose = 0;


* * enum port_e {
* *     P_ERROR = 0,
* *     P_CLOSED = 1,
* *     P_OPEN = 2,
};

enum port_e chkport(struct sockaddr_in addr);
//int v_printf(const char *fmt, ...);   /*
//* * *verbose printf */
#define v_printf(x)     if(verbose) printf x
int main(int argc, char *argv[])


* * {
* *     int index = 1, i;
* *     struct sockaddr_in addr;
* *     struct hostent *hp;


* * * *         if(argc < 2) {
* * * *                 fprintf(stderr, "Usage:\n\t%s [-v] <host>\n", argv[0]);
* * * *                 return 0;
* * * *         }
* * * *         if((argv[1][0] == '-') && argv[1][1] == 'v')
* * * *                 verbose = index++;


* * * * * *     if(index != 1 && argc == 2) {
* * * * * *             fprintf(stderr, "missing host\n");
* * * * * *             return 0;
* * * * * *     }
* * * * * *     hp = gethostbyname(argv[index]);


* * * * * * * *         if(!hp) {
* * * * * * * *                 fprintf(stderr, "could not lookup host\n");
* * * * * * * *                 return 0;
* * * * * * * *         }
* * * * * * * *         memset(&addr, 0, sizeof(addr));
* * * * * * * *         addr.sin_family = PF_INET;
* * * * * * * *         memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
* * * * * * * *         printf("Scanning Host %s\n", argv[index]);
* * * * * * * *         clock_t st = clock();


* * * * * * * * * *     for(i = 1; i <= 65535; i++) {
* * * * * * * * * *             addr.sin_port = htons(i);


* * * * * * * * * * * *                 if(!fork()) {
* * * * * * * * * * * *                         enum port_e p = chkport(addr);


* * * * * * * * * * * * * *                     switch(p) {
* * * * * * * * * * * * * *                             case P_OPEN: printf("%-4d OPEN\n", i); break;
* * * * * * * * * * * * * *                             case P_CLOSED: if(verbose) printf("%-4d CLOSED\n", i); break;
* * * * * * * * * * * * * *                             case P_ERROR: if(verbose) printf("%-4d ERROR\n", i); break;
* * * * * * * * * * * * * *                     }
* * * * * * * * * * * * * *                     exit(0);
* * * * * * * * * * * * * *             }
* * * * * * * * * * * * * *     }
* * * * * * * * * * * * * *     printf("Done in %.2lf seconds.\n", (float) (clock() - st) / CLOCKS_PER_SEC);
* * * * * * * * * * * * * *     return 0;
* * * * * * * * * * * * }

* * * * * * * * * * * * enum port_e chkport(struct sockaddr_in addr)


* * * * * * * * * * * * * * {
* * * * * * * * * * * * * *     int sd = socket(PF_INET, SOCK_STREAM, 0);
* * * * * * * * * * * * * *     enum port_e prtst = P_OPEN;
* * * * * * * * * * * * * *     if(sd < 0)
* * * * * * * * * * * * * *             return P_ERROR;
* * * * * * * * * * * * * * /*


* * * * * * * * * * * * * * * *         if(fcntl(sd, F_SETFL, O_NONBLOCK) < 0) {
* * * * * * * * * * * * * * * *                 close(sd);
* * * * * * * * * * * * * * * *                 return P_ERROR;
* * * * * * * * * * * * * * * *         }
* * * * * * * * * * * * * * * * */
* * * * * * * * * * * * * * * *         if(connect(sd, (struct sockaddr*) &addr, sizeof(addr)))
* * * * * * * * * * * * * * * *                 return P_CLOSED;
* * * * * * * * * * * * * * * *         shutdown(sd, 2);
* * * * * * * * * * * * * * * *         close(sd);
* * * * * * * * * * * * * * * *         return prtst;
* * * * * * * * * * * * * * }