fix: fdcostly should take only the prefix into account

also add tests for it

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

filter.go

@@ -20,6 +20,11 @@ func SubtractFilter(addrs ...ma.Multiaddr) func(ma.Multiaddr) bool {
 // IsFDCostlyTransport returns true for transports that require a new file
 // descriptor per connection created
 func IsFDCostlyTransport(a ma.Multiaddr) bool {
+	mas := ma.Split(a)
+	if len(mas) < 2 {
+		return false
+	}
+	a = mas[0].Encapsulate(mas[1])
 	return mafmt.TCP.Matches(a)
 }
 

filter_test.go

 package addrutil
 
 import (
-	ma "github.com/multiformats/go-multiaddr"
 	"testing"
+
+	ma "github.com/multiformats/go-multiaddr"
 )
 
 func TestSubtractAndNegFilter(t *testing.T) {
@@ -35,3 +36,50 @@ func TestIsFDCostlyTransport(t *testing.T) {
 		t.Errorf("Expected address %s to not need a new file descriptor per new connection", udpMa.String())
 	}
 }
+
+func TestIsFDCostly(t *testing.T) {
+	good := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/tcp/1234"),
+		newMultiaddr(t, "/ip4/0.0.0.0/tcp/1234"),
+		newMultiaddr(t, "/ip6/::1/tcp/1234"),
+		newMultiaddr(t, "/ip6/::/tcp/1234"),
+		newMultiaddr(t, "/ip6/fe80::1/tcp/1234"),
+		newMultiaddr(t, "/ip6/fe80::/tcp/1234"),
+		newMultiaddr(t, "/ip6/fe80::/tcp/1234/ws"),
+		newMultiaddr(t, "/ip4/127.0.0.1/tcp/1234/ws"),
+	}
+
+	bad := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/udp/1234"),
+		newMultiaddr(t, "/ip4/0.0.0.0/udp/1234/utp"),
+		newMultiaddr(t, "/ip6/::1/udp/1234"),
+		newMultiaddr(t, "/ip6/::/udp/1234"),
+	}
+
+	for _, a := range bad {
+		if IsFDCostlyTransport(a) {
+			t.Errorf("addr %s should not be fd costly", a)
+		}
+	}
+
+	for _, a := range good {
+		if !IsFDCostlyTransport(a) {
+			t.Errorf("addr %s should be fd costly", a)
+		}
+	}
+}
+
+func TestIsFdCostlyMalformed(t *testing.T) {
+	bad := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/"),
+		newMultiaddr(t, "/ip4/0.0.0.0/"),
+		newMultiaddr(t, "/ip6/::1/"),
+		newMultiaddr(t, "/ip6/::/"),
+	}
+
+	for _, a := range bad {
+		if IsFDCostlyTransport(a) {
+			t.Errorf("addr %s should not be fd costly", a)
+		}
+	}
+}