Ignore has_subnets at IPv6 part of dual stack network

But has_subnets ist still applied to
network with both addresses having a /0 address.
This closes #29

Author: hknutzen

go/pkg/pass1/setup-objects.go

@@ -269,6 +269,11 @@ func (c *spoc) setupNetwork46(a *ast.Network) {
 		n6.nat = nil
 		c.setupNetwork2(n, na4)
 		c.setupNetwork2(n6, na6)
+		// Attribute 'has_subnets' is only applied to IPv6 part,
+		// if both parts have prefix length 0 (the internet).
+		if !(n.ipp.Bits() == 0 && n6.ipp.Bits() == 0) {
+			n6.hasSubnets = false
+		}
 	} else if needV6 {
 		n.ipV6 = true
 		n.hosts = hosts6

go/testdata/ipv46-combined.t

@@ -1593,6 +1593,33 @@ Warning: IPv6 network:n1 is subnet of IPv6 network:n2
  and at IPv6 part declare attribute 'subnet_of'
 =END=
 
+############################################################
+=TITLE=Warning at combined network with has_subnets ignored at v6 part
+=INPUT=
+network:n1 = { ip = 10.1.1.0/24; ip6 = 2001:db8:1:1::/64; }
+network:n2 = { ip = 0.0.0.0/0; ip6 = 2001:db8:1:0::/48; has_subnets; }
+router:r1 = {
+ interface:n1;
+ interface:n2;
+}
+=WARNING=
+Warning: IPv6 network:n1 is subnet of IPv6 network:n2
+ in nat_domain:[network:n1].
+ If desired, split subnet into IPv4 and IPv6 part
+ and at IPv6 part declare attribute 'subnet_of'
+=END=
+
+############################################################
+=TITLE=Attribute has_subnets at combined network is not ignored with /0
+=INPUT=
+network:n1 = { ip = 10.1.1.0/24; ip6 = 2001:db8:1:1::/64; }
+network:n2 = { ip = 0.0.0.0/0; ip6 = ::/0; has_subnets; }
+router:r1 = {
+ interface:n1;
+ interface:n2;
+}
+=WARNING=NONE
+
 ############################################################
 =TITLE=Missing owner for v6 part
 =INPUT=