Viewing file:  generate-interfaces.pl (4.02 KB) -rw-r--r--
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#!/usr/bin/perl -w
# Generate an /etc/network/interfaces script based on the
# current interface and network status.
# Useful to migrate the configuration of old Debian versions (i.e. pre-woody)
# or non-Debian systems to the ifup/down scheme used in Debian.
#
# (c) 2000 Anthony Towns
# slight improvements (route parsing and direct command
# execution) done by Javier Fernandez-Sanguino
#
# TODO:
# [aj] It'd be good if it also grabbed the default gateway from route,
# and worked out the network based on the netmask and the address
# (the network is needed for ifup under 2.0.x kernels).
#
# [jfs] Some (optional) information is not parsed, like: route metrics
# and hw addresses of interfaces
use strict;
my %iface = (); # name -> iface info hash
my $ciface; # current iface name
# First, read interfaces from ifconfig
#
open (IFC,"ifconfig -a | ") || die ("Could not execute ifconfig: $!\n");
while(my $line = <IFC>) {
chomp $line;
if ($line =~ m/^(\S+)\s+(\S.*)$/) {
$ciface = $1;
$iface{$ciface} = { };
$line = $2;
} elsif ($line =~ m/^\s+(\S.*)$/) {
$line = $1;
} else {
$ciface = undef;
next;
}
next unless(defined $ciface);
if ($line =~ s/Link encap:(.*)$//) {
$iface{$ciface}->{"type"} = $1;
}
if ($line =~ s/^inet //) {
$iface{$ciface}->{"ipv4"} = "yes";
if ($line =~ s/addr:(\S*)//) {
$iface{$ciface}->{"ipv4_addr"} = $1;
}
if ($line =~ s/Bcast:(\S*)//) {
$iface{$ciface}->{"ipv4_bcast"} = $1;
}
if ($line =~ s/Mask:(\S*)//) {
$iface{$ciface}->{"ipv4_mask"} = $1;
}
}
}
close IFC;
# Now, read route information from netstat
#
open (ROU,"route -n | ") || die ("Could not execute route: $!\n");
while(my $line = <ROU>) {
chomp $line;
if ( $line =~ m/^([\d\.]+)\s+([\d\.]+)\s+([\d\.]+)\s+(\S+)\s+(\d+).*?\s+(\S+)$/) {
my $dest = $1; my $gw = $2; my $mask = $3; my $flags = $4;
my $metric = $5; my $if = $6;
if ( defined ( $iface{$if} ) ) {
if ( $dest eq "0.0.0.0" && $mask eq "0.0.0.0" ) {
# Default gateway
$iface{$if}->{"gateway"} = $gw;
} elsif ( $gw ne "0.0.0.0" ) {
# Specific (static) route
push @{$iface{$if}->{"up"}} , "route add -net $dest netmask $mask gw $gw dev $if";
push @{$iface{$if}->{"down"}} , "route del -net $dest netmask $mask gw $gw dev $if";
}
}
}
}
close ROU;
foreach my $if (keys %iface) {
if ($iface{$if}->{"type"} =~ m/loopback/i) {
if ($iface{$if}->{"ipv4"} eq "yes") {
print "iface $if inet loopback\n";
}
}
if ($iface{$if}->{"type"} =~ m/ethernet/i) {
if ($iface{$if}->{"ipv4"}) {
print "iface $if inet static\n";
if (defined $iface{$if}->{"ipv4_addr"}) {
print " address " . $iface{$if}->{"ipv4_addr"} . "\n";
}
if (defined $iface{$if}->{"ipv4_mask"}) {
print " netmask " . $iface{$if}->{"ipv4_mask"} . "\n";
}
if (defined $iface{$if}->{"ipv4_addr"}) {
print " broadcast " . $iface{$if}->{"ipv4_bcast"} . "\n";
}
if (defined $iface{$if}->{"gateway"}) {
print " gateway " . $iface{$if}->{"gateway"} . "\n";
}
if (defined $iface{$if}->{"pre-up"}) {
while ( my $upcmd = pop @{$iface{$if}->{"pre-up"}} ) {
print " pre-up " . $upcmd . "\n";
}
}
if (defined $iface{$if}->{"up"}) {
while ( my $upcmd = pop @{$iface{$if}->{"up"}} ) {
print " up " . $upcmd . "\n";
}
}
if (defined $iface{$if}->{"down"}) {
while ( my $downcmd = pop @{$iface{$if}->{"down"}} ) {
print " down " . $downcmd . "\n";
}
}
if (defined $iface{$if}->{"post-down"}) {
while ( my $downcmd = pop @{$iface{$if}->{"pre-down"}} ) {
print " pre-down " . $downcmd . "\n";
}
}
}
}
print "\n";
}
exit 0;
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