AMPR-Rip44

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bin/rip44d  view on Meta::CPAN

{
	my $s = `$ifconfig -a`;
	
	while ($s =~ s/inet addr:(\d+\.\d+\.\d+\.\d+)//) {
		warn "found local address: $1\n" if ($verbose);
		$my_addresses{$1} = 1;
	}
}

# Convert a netmask (in integer form) to the corresponding prefix length,
# and validate it too. This is a bit ugly, optimizations are welcome.

sub mask2prefix($)
{
	my($mask) = @_; # integer
	
	# convert to a string of 1's and 0's, like this (/25):
	# 11111111111111111111111110000000
	my($bits) = unpack("B32", pack('N', $mask));
	
	# There should be a continuous row of 1's in the

bin/rip44d  view on Meta::CPAN

	}
	
	if ($e_passwd ne $rip_passwd) {
		warn "RIPv2 invalid password $e_passwd\n" if ($verbose);
		return 0;
	}
	
	return 1;
}

# validate a route entry, make sure we can rather safely
# insert it in the routing table

sub validate_route($$$$$)
{
	my($e_net_i, $e_net_s, $e_netmask, $e_netmask_s, $e_nexthop_s) = @_;
	
	# netmask is correct and not too wide
	my $prefix_len = mask2prefix($e_netmask);
	if ($prefix_len < 0) {
		warn "invalid netmask: $e_netmask_s\n" if ($verbose);
		return (0, 'invalid netmask');
	}
	

bin/rip44d  view on Meta::CPAN

	my $e_net_i = unpack('N', $e_net);
	my $e_netmask = substr($entry, 8, 4);
	my $e_netmask_i = unpack('N', $e_netmask);
	my $e_nexthop = substr($entry, 12, 4);
	my $e_metric = unpack('N', substr($entry, 16, 4));
	my $e_net_s = inet_ntoa($e_net);
	my $e_netmask_s = inet_ntoa($e_netmask);
	my $e_nexthop_s = inet_ntoa($e_nexthop);
	
	# Validate the route
	my($result, $reason) = validate_route($e_net_i, $e_net_s, $e_netmask_i, $e_netmask_s, $e_nexthop_s);
	if (!$result) {
		warn "entry ignored ($reason): af $e_af rtag $e_rtag $e_net_s/$e_netmask_s via $e_nexthop_s metric $e_metric\n" if ($verbose);
		return 0;
	}
	
	warn "entry: af $e_af rtag $e_rtag $e_net_s/$e_netmask_s via $e_nexthop_s metric $e_metric\n" if ($verbose > 1);
	
	# Ok, we have a valid route, consider adding it in the kernel's routing table
	consider_route($e_net_s, $e_netmask_s, $e_nexthop_s, $e_rtag);
	
	return 1;
}

# process a RIP message

sub process_msg($$$)
{
	my($addr_s, $perr_port, $msg) = @_;
	
	# validate packet's length
	if (length($msg) < RIP_HDR_LEN + RIP_ENTRY_LEN) {
		warn "$me: ignored too short packet from $addr_s: " . length($msg) . "\n";
		return -1;
	}
	
	if (length($msg) > RIP_HDR_LEN + RIP_ENTRY_LEN*25) {
		warn "$me: ignored too long packet from $addr_s: " . length($msg) . "\n";
		return -1;
	}
	
	# packet's length must be divisible by the length of an entry
	if ((length($msg) - RIP_HDR_LEN) % RIP_ENTRY_LEN != 0) {
		warn "$me: ignored invalid length packet from $addr_s: " . length($msg) . "\n";
		return -1;
	}
	
	# validate RIP packet header
	my $hdr = substr($msg, 0, 4);
	my $entries = substr($msg, 4);
	
	my($rip_command, $rip_version, $zero1, $zero2) = unpack('C*', $hdr);
	if ($rip_command != RIP_CMD_RESPONSE) {
		warn "$me: ignored non-response RIP packet from $addr_s\n";
		return -1;
	}
	if ($rip_version != 2) {
		warn "$me: ignored RIP version $rip_version packet from $addr_s (only accept v2)\n";

lib/AMPR/Rip44.pm  view on Meta::CPAN

=cut

sub fill_local_ifs() {

}

=head2 mask2prefix

Convert a netmask (in integer form) to the corresponding prefix length,
and validate it too. This is a bit ugly, optimizations are welcome.

=cut

sub mask2prefix ($) {
	my($mask) = @_; # integer

}