dgd: various improvements.

* dgd/dgd (get_default_gw): Rename to get_default_iface.  Compare
gateway interface name, instead of the gw address.  All uses changed.
(scan_links): Add missing conditional.
Never exit on 'no active link configured'.
(updown): If $name argument is a hash reference, read link parameters
from it and pass it to the script in the command line.
(serialize_link, cmplinks): New functions.
(SIGHUP handler): Save away active link before reconfiguring. Call
'down', if it was removed.

1 files changed, 60 insertions, 24 deletions

diff --git a/dgd/dgd b/dgd/dgd
index 1aeac04..dba3bb1 100755
--- a/dgd/dgd
+++ b/dgd/dgd
@@ -324,18 +324,20 @@ sub readconfig {
     return $err;
 }
 
-sub get_default_gw {
-    my $gw;
+sub get_default_iface {
+    my $ret;
     open(my $fd, '-|', "netstat -rn")
 	or abend(EX_OSFILE, "can't start netstat: $!");
     while (<$fd>) {
-	if (/^0\.0\.0\.0\s+(\S+)/) {
-	    $gw = $1;
+	chomp;
+	my ($dest,$gw,undef,undef,undef,undef,undef,$iface) = split /\s+/;
+	if ($dest eq "0.0.0.0") {
+	    $ret = $iface;	
 	    last;
 	}
     }
     close $fd;
-    return $gw;
+    return $ret;
 }
 
 sub scan_links {
@@ -356,24 +358,28 @@ sub scan_links {
 	for ($active_link = 0; $active_link <= $#links; ++$active_link) {
 	    last if $links[$active_link]->{name} eq $config{core}{active};
 	}
-        error("no link corresponding to the active one");
-	$active_link = undef;
-        delete $config{core}{active};
+	if ($active_link > $#links) {
+	    error("no link corresponding to the active one");
+	    $active_link = undef;
+	    delete $config{core}{active};
+	}
     } 
 
     unless (defined($active_link)) {
-	my $gw = get_default_gw();
-	if (defined($gw)) {
-	    debug(1, "default gw $gw");
+	my $iface = get_default_iface();
+	if (defined($iface)) {
+	    debug(1, "default gw via $iface");
 
 	    for ($active_link = 0; $active_link <= $#links; ++$active_link) {
-		last if $links[$active_link]->{gw} eq $gw;
+		last if $links[$active_link]->{if} eq $iface;
 	    }
 
-	    abend(EX_CONFIG, "no active link configured")
-		if ($active_link > $#links);
-	    
-	    debug(1, "active link $links[$active_link]->{name}");
+            if ($active_link > $#links) {
+	        debug(1, "no active link configured");
+	        $active_link = undef;
+            } else {
+	        debug(1, "active link $links[$active_link]->{name}");
+	    }
 	} else {
 	    debug(1, "no active link configured");
 	    $active_link = undef;
@@ -403,12 +409,13 @@ sub runcmd {
 
 sub updown {
     my ($what, $name) = @_;
-
-    my $cmd = defined($config{link}{$name}{$what})
-	       ? $config{link}{$name}{$what}
-	       : $config{core}{$what};
+    my $link = (ref($name) eq 'HASH') ? $name : $config{link}{$name};
+    my $cmd = defined($link->{$what}) ? $link->{$what} : $config{core}{$what};
     if (defined($cmd)) {
-	runcmd("$cmd $name");
+	$cmd .= " '$link->{name}'";
+	$cmd .= " '$link->{if}' '$link->{ip}' '$link->{gw}' '$link->{ns}' '$link->{net}'"
+	    if (ref($name) eq 'HASH');
+	runcmd($cmd);
     } elsif ($what eq 'up') {
 	runcmd("route add default gw $config{link}{gw}");
     } elsif ($what eq 'down') {
@@ -429,7 +436,7 @@ sub check_links {
     foreach $link (@links) {
 	$link->{alive} = 0;
     }
-    debug(1, "checking links");
+    debug(1, "checking links ".($#links+1).", probes $config{core}{probes}");
     my $p = Net::Ping->new("icmp", $config{core}{timeout});
     for (my $i = 0; $i < $config{core}{probes}; $i++) {
 	foreach $link (@links) {
@@ -467,6 +474,23 @@ sub newlink {
     error("no fallback link");
 }
 
+sub serialize_link {
+    my $link = shift;
+
+    my $s;
+    foreach my $k (sort keys %{$link}) {
+	next if ($k eq 'alive');
+	$s .= ';' if defined $s;
+	$s .= "$k=$link->{$k}";
+    }
+    return $s;
+}
+
+sub cmplinks {
+    my ($aref, $bref) = @_;
+    return serialize_link($aref) eq serialize_link($bref);
+}
+
 # ########
 my $foreground;
 
@@ -528,12 +552,24 @@ unless ($foreground) {
 }
 
 $SIG{HUP} = sub {
+    my %save_link = %{$links[$active_link]} if defined $active_link;
     my %t = %defconfig;
     diag('info', "re-reading configuration file");
     if (readconfig($conffile, \%t) == 0) {
 	%config = %t;
 	@links = ();
 	scan_links;
+	if (keys(%save_link)) {
+            my $i;
+	    for ($i = 0; $i <= $#links; ++$i) {
+		last if cmplinks(\%save_link, $links[$i]);
+	    }
+	    if ($i > $#links) {
+		debug(1, "active link $save_link{name} was removed");
+		updown('down', \%save_link);
+		$active_link = undef;
+	    }
+	}
     }
 };
 
@@ -673,8 +709,8 @@ marked as I<alive>.  Default is 2
     
 =item B<active => I<STRING>
 
-Name of the active link.  If not defined, the link whose B<gw> variable
-matches the default gateway address is assumed active. 
+Name of the active link.  If not defined, the link whose B<if> variable
+matches the interface name of the default gateway is assumed active. 
 
 =item B<logpriority => B<0>|B<1>