Date: Thu, 10 Aug 95 16:34:12 -0400 From: Gary Stanny <stanny@laa.com> To: hackers@FreeBSD.ORG Cc: questions@freefall.FreeBSD.org.gary Subject: Telnet can connect to a port but I can't Message-ID: <9508102034.AA01308@handset.laa.com>
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I'm not sure it this question should go to questions or hackers so I
am posting it to both. So network wizards from both areas please feel
free to enlighten me.
I am trying to use FreeBSD to write a simple protocol converter - using
code straight from Stevens' book (Unix Network Programming) but I am get-
ting a couple of errors. Can anyone see what I am doing wrong ?
The port is listening on the remote machine (netstat says the state of
the port is LISTEN) & telnet can connect to it, but my program fails to
connect it.
tdf_ltd >udp2tcp -i23456 -o12345 -d204.7.172.60 -a1
udp2tcp converter V1.0
udp2tcp: Can't bind TCP local address : Can't assign requested address
The port is listening on the local machine & telnet can connect to it,
but my program fails to connect it and I get a different error then
the remote host tests.
tdf_ltd >udp2tcp -i23456 -o12345 -d127.0.0.1 -a1
udp2tcp converter V1.0
udp2tcp: Can't bind TCP local address : Address already in use
What does telnet do to the socket&|port that I'm not ???
/*-----------------------------------------------------------------*/
/*
udp2tcp.c
This program grabs a UDP packet off a target port, converts it
to TCP &
slams it out another port.
*/
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
/*-----------------------------------------------------------------*/
int debug_flag , inputPort , outputPort , auditorNumber ;
char *destAddress ;
int sock_in , sock_out ;
struct sockaddr_in destAddr , sourceAddr ;
ARG arg_table[] = {
{ 'a' , INTEGER , &auditorNumber , "Auditor log file number" } ,
{ 'd' , STRING , ( int * ) &destAddress , "Destination IP
address" } ,
{ 'i' , INTEGER , &inputPort , "Input port number" } ,
{ 'o' , INTEGER , &outputPort , "Output port number" } ,
{ 'D' , BOOLEAN , &debug_flag , "Runtime debug flag" } ,
} ;
#define ARG_TABLE_SIZE ( sizeof( arg_table ) / sizeof( ARG ) )
/*-----------------------------------------------------------------*/
int main( int argc , char *argv[] )
{
int new_argc , i ;
new_argc = getargs( argc , argv , arg_table , ARG_TABLE_SIZE ) ;
printf( "udp2tcp converter V%s\n" , VERSION_NUMBER ) ;
/* open the TCP output socket */
if( ( sock_out = socket( AF_INET , SOCK_STREAM , 0 ) ) < 0 ) {
perror( "udp2tcp: Can't open TCP socket " ) ;
return ERR_SOCKET_OPEN_FAILURE ;
}
bzero( ( char * ) &destAddr , sizeof( destAddr ) ) ;
destAddr.sin_family = AF_INET ;
destAddr.sin_addr.s_addr = inet_addr( destAddress ) ;
destAddr.sin_port = htons( outputPort ) ;
if( bind( sock_out , (struct sockaddr *) &destAddr , sizeof(
destAddr ) ) < 0 ) {
perror( "udp2tcp: Can't bind TCP local address " ) ;
return ERR_BIND_FAILURE ;
}
/* open the UDP input socket */
if( ( sock_in = socket( AF_INET , SOCK_DGRAM , 0 ) ) < 0 ) {
perror( "udp2tcp: Can't open UDP socket " ) ;
return ERR_SOCKET_OPEN_FAILURE ;
}
bzero( ( char * ) &sourceAddr , sizeof( sourceAddr ) ) ;
sourceAddr.sin_family = AF_INET ;
sourceAddr.sin_addr.s_addr = htonl( INADDR_ANY ) ;
sourceAddr.sin_port = htons( inputPort ) ;
if( bind( sock_in , (struct sockaddr *) &sourceAddr , sizeof(
sourceAddr ) ) < 0 ) {
perror( "udp2tcp: Can't bind UDP local address " ) ;
return ERR_BIND_FAILURE ;
}
echoThePackets( sock_in ) ;
return SS_NORMAL ;
}
/*-----------------------------------------------------------------*/
void echoThePackets( int input_sock )
{
int n , n2 ;
char buff[ MAX_PACKET ] , temp[ MAX_PACKET + 25 ] ;
while( TRUE ) {
n = recvfrom( input_sock , buff , MAX_PACKET , 0 ,
(struct sockaddr *) 0 , (int *) 0 ) ;
if( n < 0 ) {
perror( "udp2tcp: Input - recvfrom error " ) ;
localExit( ERR_SOCKET_READ_ERROR ) ;
}
if( n == 0 )
return ;
n2 = sendto( sock_out , buff , n , 0 ,
(struct sockaddr *) &destAddr , sizeof( destAddr) ) ;
if( n2 < 0 ) {
perror( "udp2tcp: Output - sendto error " ) ;
localExit( ERR_SOCKET_WRITE_ERROR ) ;
}
}
}
/*-----------------------------------------------------------------*/
thanks a bunch in advance
cheers
gary
Gary Stanny Lynn-Arthur Associates, Inc. +1 313 995 5590
stanny@laa.com Operations Support Systems +1 313 995 5989 (fax)
2350 Green Road Suite 160 Ann Arbor, MI,
48105 USA
cheers
gary
Gary Stanny Lynn-Arthur Associates, Inc. +1 313 995 5590
stanny@laa.com Operations Support Systems +1 313 995 5989 (fax)
2350 Green Road Suite 160 Ann Arbor, MI, 48105 USA
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