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/*
* IP Autoforward Control Program v0.20
*
* Copyright (c) 1996 Richard Lynch
*
* Distributed under GPL.
*
* This program should be used with conjunction with the Autoforward kernel
* patch. It establishes and modifies the tables which the kernel uses to
* automatically add masquerade entries.
*
* Please send any comments, bug reports, and suggestions to
* rlynch@scoot.netis.com
*
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
/* necessary for some older kernels */
#ifndef CONFIG_IP_MASQUERADE_IPAUTOFW
#define CONFIG_IP_MASQUERADE_IPAUTOFW
#endif
#include <net/if.h>
#include <linux/timer.h>
#include <netinet/ip_fw.h>
#include "ip_fw.h"
#include <netdb.h>
#include <ctype.h>
#include <stdio.h>
int main(int argc, char * argv [])
{
struct ip_autofw af;
int socket_fd;
int index;
int command;
int verbose;
short int b1,b2,b3,b4;
char *tmp;
b1=0;
b2=0;
b3=0;
b4=0;
verbose=0;
command=0;
af.type=0;
af.low=0;
af.high=0;
af.visible=0;
af.hidden=0;
af.protocol=0;
af.lastcontact=0;
af.where=0;
af.ctlproto=0;
af.ctlport=0;
af.flags=IP_AUTOFW_USETIME | IP_AUTOFW_SECURE;
af.next=NULL;
if (argc<2)
{
printf("Usage:\n");
printf(" ipautofw <command> <options>\n\n");
printf("Valid commands:\n");
printf(" -A add new autoforward entry\n");
printf(" -D delete an autoforward entry\n");
printf(" -F flush the autoforward table\n");
printf("\nValid options:\n");
printf(" -r <type> <low> <high> forwarding on ports <low> to <high> using\n");
printf(" protocol <type> (tcp or udp)\n\n");
printf(" -h <host> IP address of host to receive forwarded\n");
printf(" packets\n\n");
printf(" -d <type> <low> <high> specifies a set of ports which will not use\n");
printf(" the default high range (60000+) masquerade\n");
printf(" port area\n\n");
printf(" -p <type> <visible> <host>:<hidden>\n");
printf(" set up port bouncing from visible host port\n");
printf(" to masqueraded host <host> on port <hidden>,\n");
printf(" protocol <type> (currently not supported)\n\n");
printf(" -c <type> <port> specifies a control port and protocol\n\n");
printf(" -u Do _not_ require that a host connect within\n");
printf(" 15 seconds of triggering the control port\n\n");
printf(" -i Insecure mode; any host many connect after\n");
printf(" implied by not using the -c option or implied\n");
printf(" by using the -h option\n");
printf(" once the control port has been triggered\n");
printf(" -v Verbose mode\n\n");
exit(1);
}
switch(argv[1][1])
{
case 'A':
command=IP_AUTOFW_ADD;
break;
case 'D':
command=IP_AUTOFW_DEL;
break;
case 'F':
command=IP_AUTOFW_FLUSH;
break;
default:
printf("Command must be either -A, -D, or -F\n");
exit(1);
}
if (argc>2 && command==IP_AUTOFW_FLUSH)
{
printf("The flush command does not take options\n");
exit(1);
}
for (index=2;index<argc;index++)
{
if (*argv[index]=='-')
{
switch (argv[index][1])
{
case 'r':
tmp=argv[index+1];
if (*tmp!='t' && *tmp!='u')
{
printf("protocol must be either tcp or udp\n");
exit(1);
}
if (*tmp=='t')
af.protocol=IPPROTO_TCP;
else
af.protocol=IPPROTO_UDP;
sscanf(argv[index+2],"%hu",&af.low);
sscanf(argv[index+3],"%hu",&af.high);
if (af.low==0 || af.high==0 || af.high<af.low)
{
printf("Illegal port numbers\n");
exit(1);
}
index+=3;
if (af.type)
{
printf("-r cannot be used in conjunction with -p or -d\n");
exit(1);
}
af.type=IP_FWD_RANGE;
break;
case 'd':
tmp=argv[index+1];
if (*tmp!='t' && *tmp!='u')
{
printf("protocol must be either tcp or udp\n");
exit(1);
}
if (*tmp=='t')
af.protocol=IPPROTO_TCP;
else
af.protocol=IPPROTO_UDP;
sscanf(argv[index+2],"%hu",&af.low);
sscanf(argv[index+3],"%hu",&af.high);
if (af.low==0 || af.high==0 || af.high<af.low)
{
printf("Illegal port numbers\n");
exit(1);
}
index+=3;
if (af.type)
{
printf("-d cannot be used in conjunction with -p or -r\n");
exit(1);
}
af.type=IP_FWD_DIRECT;
break;
case 'h':
if (sscanf(argv[index+1],"%hd.%hd.%hd.%hd",&b1,&b2,&b3,&b4)<0)
{
printf("Invalid IP address: %s\n",argv[index+1]);
exit(1);
}
af.where=b1+b2*256+b3*256*256+b4*256*256*256;
af.flags&=IP_AUTOFW_SECURE ^ 0xFFFF;
index++;
break;
case 'p':
tmp=argv[index+1];
if (*tmp!='t' && *tmp!='u')
{
printf("protocol must be either tcp or udp\n");
exit(1);
}
if (*tmp=='t')
af.protocol=IPPROTO_TCP;
else
af.protocol=IPPROTO_UDP;
sscanf(argv[index+2],"%hu",&af.visible);
sscanf(argv[index+3],"%hu.%hu.%hu.%hu:%hu",&b1,&b2,&b3,&b4,&af.hidden);
af.where=b1+b2*256+b3*256*256+b4*256*256*256;
if (af.visible==0 || af.hidden==0)
{
printf("Illegal port numbers\n");
exit(1);
}
index+=3;
if (af.type)
{
printf("-p cannot be used in conjunction with -r or -d\n");
exit(1);
}
af.type=IP_FWD_PORT;
break;
case 'c':
tmp=argv[index+1];
if (*tmp!='t' && *tmp!='u')
{
printf("Control protocol must be either tcp or udp\n");
exit(1);
}
if (*tmp=='t')
af.ctlproto=IPPROTO_TCP;
else
af.ctlproto=IPPROTO_UDP;
sscanf(argv[index+2],"%hu",&af.ctlport);
index+=2;
break;
case 'u':
af.flags&=IP_AUTOFW_USETIME ^ 0xFFFF;
break;
case 'i':
af.flags&=IP_AUTOFW_SECURE ^ 0xFFFF;
break;
case 'v':
verbose=1;
break;
default:
printf("Invalid option: %s\n",argv[index]);
exit(1);
}
}
else
{
printf("Invalid option: %s\n",argv[index]);
}
}
if (af.where && (af.flags & IP_AUTOFW_SECURE) && af.type!=IP_FWD_PORT)
{
printf("Cannot use -h in secure mode\n");
}
if (!(af.ctlport && af.ctlproto))
{
af.flags&=IP_AUTOFW_SECURE ^ 0xFFFF;
}
if (af.ctlport && af.ctlproto && !(af.flags & IP_AUTOFW_SECURE))
{
printf("-i cannot be specified with a control port\n");
}
if (!af.type && command!=IP_AUTOFW_FLUSH)
{
printf("You must select a type of forwarding (direct, port, or range)\n");
exit(1);
}
if (verbose)
{
switch(command)
{
case IP_AUTOFW_ADD:
printf("Adding autofwd ");
break;
case IP_AUTOFW_DEL:
printf("Deleteing autofwd ");
break;
case IP_AUTOFW_FLUSH:
printf("Flushing autoforward table\n");
break;
}
if (command!=IP_AUTOFW_FLUSH)
{
if (af.type==IP_FWD_DIRECT)
printf("(direct) ports %hu - %hu\n",af.low,af.high);
if (af.type==IP_FWD_PORT)
printf("%s port %hu -> %hd.%hd.%hd.%hd:%hu ",(af.protocol==IPPROTO_TCP ? "tcp" : "udp" ), af.visible,af.where & 255, (af.where >> 8) & 255, (af.where >> 16) & 255, (af.where >> 24) & 255,af.hidden);
if (af.type==IP_FWD_RANGE)
{
printf("%s ports %hu - %hu ",(af.protocol==IPPROTO_TCP ? "tcp" : "udp" ),af.low,af.high);
if (af.where)
printf("to fixed host %hd.%hd.%hd.%hd ",af.where & 255, (af.where >> 8) & 255, (af.where >> 16) & 255, (af.where >> 24) & 255);
}
if (af.ctlproto && af.ctlport)
printf("via %s ctl port %hu ",(af.ctlproto==IPPROTO_TCP ? "tcp" : "udp" ),af.ctlport);
}
if (af.flags & IP_AUTOFW_USETIME)
printf("U");
if (af.flags & IP_AUTOFW_SECURE)
printf("S");
printf("\n");
}
socket_fd=socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
if (setsockopt(socket_fd, IPPROTO_IP, command, &af, sizeof(af))<0)
perror("setsockopt");
exit(0);
}
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