Date: Fri, 12 Jan 2001 13:08:32 -0500 From: Larry Baird <lab@gta.com> To: freebsd-net@freebsd.org Subject: Strange source address problem Message-ID: <3A5F4820.634D626B@gta.com>
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Hopefully somebody can shed some light in helping me to understand
something I am seeing on a 4.2 box. I am experimenting with a daemon
that implements something very close to the VRRP (Virtual Router
Redundancy Protocol). The VRRP portion of the daemon works correctly.
The problem I am having has to do with the source IP address after a
host
has transitioned from "slave" to "master" mode.
The problem can be illustrated on a standard 4.2 system not
running the VRRP daemon by the following command line actions:
Script started on Fri Jan 12 12:42:35 2001
sukebe# ifconfig xl0 inet 192.168.23.85
sukebe#
sukebe# ifconfig xl0
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::260:8ff:feaf:2bf5%xl0 prefixlen 64 scopeid 0x1
inet 192.168.23.85 netmask 0xffffff00 broadcast 192.168.23.255
ether 00:60:08:af:2b:f5
media: autoselect (none) status: no carrier
supported media: autoselect 100baseTX <full-duplex> 100baseTX
10baseT/UTP <full-duplex> 10baseT/UTP 100baseTX <hw-loopback>
sukebe#
sukebe# ./getLocalIP 192.168.23.90
local = 192.168.23.85:1178
sukebe#
sukebe# ifconfig xl0 inet 192.168.23.86
sukebe#
sukebe# ifconfig xl0
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::260:8ff:feaf:2bf5%xl0 prefixlen 64 scopeid 0x1
inet 192.168.23.86 netmask 0xffffff00 broadcast 192.168.23.255
ether 00:60:08:af:2b:f5
media: autoselect (none) status: no carrier
supported media: autoselect 100baseTX <full-duplex> 100baseTX
10baseT/UTP <full-duplex> 10baseT/UTP 100baseTX <hw-loopback>
sukebe#
sukebe# ./getLocalIP 192.168.23.90
local = 192.168.23.85:1179
^^^^ why is 192.168.23.85 still showing up?? This address should be
gone.
sukebe#
sukebe# exit
Script done on Fri Jan 12 12:44:35 2001
I have attached the source code to the getLocalIP program. Can
anybody explain this? Thanks in advance for your help.
--
------------------------------------------------------------------------
Larry Baird
Global Technology Associates, Inc. | Orlando, FL
Email: lab@gta.com | TEL 407-380-0220, FAX 407-380-6080
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name="getLocalIP.c"
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filename="getLocalIP.c"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
int s;
if ( argc != 2 )
fprintf( stderr, "USAGE: %s destIP[:port]\n", argv[0] );
else {
if ( (s = socket( PF_INET, SOCK_DGRAM, 0 )) < 0 )
perror( "Unable to create socket" );
else {
struct sockaddr_in servAddr;
short port = 7;
char *p;
if ((p = strchr(argv[1], ':')) != NULL) {
port = atoi(p + 1);
*p = 0;
}
bzero(&servAddr, sizeof(servAddr));
servAddr.sin_family = AF_INET;
servAddr.sin_port = htons( port );
if ( ! inet_aton( argv[1], &servAddr.sin_addr ) )
fprintf( stderr, "IP address invalid.\n" );
else {
if ( connect( s,
(struct sockaddr *)&servAddr,
sizeof(servAddr) ) )
perror( "connect() failed" );
else {
struct sockaddr_in local;
int local_len = sizeof(local);
if ( getsockname( s,
(struct sockaddr *)&local,
&local_len))
perror( "getsockname() failed" );
else {
printf( "local = %s:%d\n",
inet_ntoa(local.sin_addr),
ntohs(local.sin_port));
exit( 0 );
}
}
}
close(s);
}
}
exit( 1 );
}
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