Show warning for useless subnet_of at NAT network

This fixes #31

Author: hknutzen

go/pkg/pass1/find-subnets.go

@@ -494,7 +494,7 @@ func (c *spoc) findSubnetsInNatDomain0(domains []*natDomain, networks netList) {
 				// there's no method to specify a natted network
 				// as value of subnet_of.
 				if natSubnet.subnetOf == bignet {
-					subnet.subnetOfUsed = true
+					natSubnet.subnetOfUsed = true
 				} else if bignet.hasSubnets &&
 					(bignet.ipp.Bits() == 0 ||
 						zoneEq(bignet.zone, subnet.zone) ||
@@ -629,12 +629,18 @@ func isLoopbackAtZoneBorder(sub, big *network) bool {
 }
 
 func (c *spoc) findUselessSubnetAttr() {
-	for _, n := range c.allNetworks {
+	check := func(n *network) {
 		if bignet := n.subnetOf; bignet != nil && !n.subnetOfUsed {
-			c.warn("Useless 'subnet_of = %s' at %s", bignet, n.vxName())
+			c.warn("Useless 'subnet_of = %s' at %s", bignet, natName(n))
 		}
 		if n.hasSubnets && !n.hasSubnetsUsed {
-			c.warn("Useless 'has_subnets' at %s", n.vxName())
+			c.warn("Useless 'has_subnets' at %s", natName(n))
+		}
+	}
+	for _, n := range c.allNetworks {
+		check(n)
+		for _, nn := range n.nat {
+			check(nn)
 		}
 	}
 }

go/pkg/pass1/set-zone.go

@@ -1004,7 +1004,10 @@ func (c *spoc) inheritNAT0() {
 		return m1, from1
 	}
 	for _, n := range c.allNetworks {
-		inherit(n)
+		switch n.ipType {
+		case hasIP, bridgedIP:
+			inherit(n)
+		}
 	}
 }
 
@@ -1021,11 +1024,12 @@ func (c *spoc) adaptNAT(n *network, tag string, nat *network) *network {
 	subNat.name = n.name
 	subNat.descr = "nat:" + tag + " of " + n.name
 
-	// Always keep attribute subnetOf of inherited NAT with dynmic NAT,
-	// because it would override existing subnet relation of networks.
-	// Otherwies take attribute subnetOf of original network if available.
+	// Always keep attribute subnetOf of inherited NAT with dynamic or
+	// hidden NAT, because it would override existing subnet relation
+	// of networks.
+	// Otherwise take attribute subnetOf of original network if available.
 	// Else keep attribute subnetOf of inherited NAT.
-	if s := n.subnetOf; s != nil && !(subNat.subnetOf != nil && subNat.dynamic) {
+	if s := n.subnetOf; s != nil && !subNat.dynamic {
 		subNat.subnetOf = s
 	}
 

go/testdata/nat.t

@@ -4626,6 +4626,57 @@ router:r1 = {
 Warning: Useless 'subnet_of = network:n2' at network:n1
 =END=
 
+############################################################
+=TITLE=Useless subnet_of at NAT network
+=INPUT=
+network:n1 = {
+ ip = 10.1.1.0/24;
+ nat:n1 = { ip = 10.1.7.0/24; subnet_of = network:n2; }
+ nat:h1 = { hidden; }
+ nat:n2 = { identity; }
+}
+network:n2 = {
+ ip = 10.1.0.0/21;
+ nat:n2 = { hidden; }
+}
+network:n3 = {
+ ip = 10.1.3.0/24;
+ subnet_of = network:n2;
+ nat:n2 = { identity; }
+}
+router:r1 = {
+ interface:n1 = { nat_out = n2; }
+ interface:n2 = { nat_out = h1; }
+ interface:n3 = { nat_out = n1, n2; }
+}
+=WARNING=
+Warning: Useless 'subnet_of = network:n2' at nat:n1 of network:n1
+=END=
+
+############################################################
+=TITLE=Show useless subnet_of at network even if subnet_of at NAT is used
+=INPUT=
+network:n1 = {
+ ip = 10.1.1.0/24;
+ subnet_of = network:n2;
+ nat:n1 = { ip = 10.7.7.0/24; subnet_of = network:n3; }
+ nat:h1 = { hidden; }
+ nat:n2 = { identity; }
+}
+network:n2 = {
+ ip = 10.1.0.0/21;
+ nat:n2 = { hidden; }
+}
+network:n3 = { ip = 10.7.0.0/16; }
+router:r1 = {
+ interface:n1 = { nat_out = n2; }
+ interface:n2 = { nat_out = h1; }
+ interface:n3 = { nat_out = n1, n2; }
+}
+=WARNING=
+Warning: Useless 'subnet_of = network:n2' at network:n1
+=END=
+
 ############################################################
 =TITLE=Useless subnet_of with network 0/0 present
 =INPUT=