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@olbat olbat/portscanner.c
Created Sep 19, 2011

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What would you like to do?
Scan a specific machine to see which ports it's listening on
/*
* Copyright (C) 2006, 2007 Sarzyniec Luc <mail@olbat.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* see the COPYING file for more informations */
/* Output:
OPEN : listening on the specified port
CLOSE : refuse connection on the specified port
TIMEOUT : don't answer on the specified port
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/time.h>
#define PORT_MIN 0
#define PORT_MAX 65535
#define TIMEOUT 1 /* in seconds */
#define DISPLAY_OPEN 0x1
#define DISPLAY_CLOSE 0x2
#define DISPLAY_TIMEOUT 0x4
int main(int argc, char **argv)
{
int sockfd,pstart,pend;
char mode;
struct timeval timeout;
struct sockaddr_in sain;
struct hostent *host;
if (argc < 2)
{
printf("usage: %s <IP/host> [<mode> <port start> <port end>]\n"
"-modes:"
"\t%#.2x display OPEN\n"
"\t%#.2x display CLOSE\n"
"\t%#.2x display TIMEOUT\n"
"\t(default is OPEN)\n",
argv[0],DISPLAY_OPEN,DISPLAY_CLOSE,DISPLAY_TIMEOUT);
exit(1);
}
if ((inet_aton(argv[1],&(sain.sin_addr))) == 0)
{
if ((host = gethostbyname(argv[1])) == 0)
{
perror("gethostbyname");
exit(1);
}
else
{
memcpy(&(sain.sin_addr),host->h_addr,
sizeof(sain.sin_addr));
}
}
if (argc > 2)
{
mode = (char) atoi(argv[2]);
if (!(mode & DISPLAY_OPEN) && !(mode & DISPLAY_CLOSE)
&& !(mode & DISPLAY_TIMEOUT))
{
printf("error: wrong mode\n");
exit(1);
}
}
else
{
mode = DISPLAY_OPEN;
}
sain.sin_family = AF_INET;
memset(sain.sin_zero,0,sizeof(sain.sin_zero));
timeout.tv_sec = TIMEOUT;
timeout.tv_usec = 0;
if (argc > 3)
pstart = atoi(argv[3]);
else
pstart = PORT_MIN;
if (argc > 4)
pend = atoi(argv[4]);
else
pend = PORT_MAX;
if (pstart > pend)
{
sockfd = pend;
pend = pstart;
pstart = sockfd;
}
for (;pstart <= pend;pstart++)
{
sain.sin_port = htons(pstart);
if ((sockfd = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP)) <= 0)
perror("socket");
if (setsockopt(sockfd,SOL_SOCKET,SO_SNDTIMEO,
&timeout,sizeof(timeout)))
perror("setsockopt");
if (connect(sockfd,(struct sockaddr *)&sain,
sizeof(struct sockaddr)))
{
if (errno == ECONNREFUSED)
{
if (mode & DISPLAY_CLOSE)
printf("\015%hu CLOSE\n",
ntohs(sain.sin_port));
else
{
printf("\015%u",pstart);
fflush(stdout);
}
}
else if ((errno == ETIMEDOUT) || (errno == EINPROGRESS))
{
if (mode & DISPLAY_TIMEOUT)
printf("\015%hu TIMEOUT\n",
ntohs(sain.sin_port));
else
{
printf("\015%u",pstart);
fflush(stdout);
}
}
else
{
perror("connect");
}
}
else
{
if (mode & DISPLAY_OPEN)
printf("\015%hu OPEN\n",ntohs(sain.sin_port));
else
{
printf("\015%u",pstart);
fflush(stdout);
}
}
close(sockfd);
}
return 0;
}
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