move FilterAddrs here from go-addr-util

net/filter.go

@@ -0,0 +1,19 @@
+package manet
+
+import ma "github.com/multiformats/go-multiaddr"
+
+// FilterAddrs is a filter that removes certain addresses, according to the given filters.
+// If all filters return true, the address is kept.
+func FilterAddrs(a []ma.Multiaddr, filters ...func(ma.Multiaddr) bool) []ma.Multiaddr {
+	b := make([]ma.Multiaddr, 0, len(a))
+	for _, addr := range a {
+		good := true
+		for _, filter := range filters {
+			good = good && filter(addr)
+		}
+		if good {
+			b = append(b, addr)
+		}
+	}
+	return b
+}

net/filter_test.go

@@ -0,0 +1,30 @@
+package manet
+
+import (
+	"testing"
+
+	ma "github.com/multiformats/go-multiaddr"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFilterAddrs(t *testing.T) {
+	bad := []ma.Multiaddr{
+		newMultiaddr(t, "/ip6/fe80::1/tcp/1234"),   // link local
+		newMultiaddr(t, "/ip6/fe80::100/tcp/1234"), // link local
+	}
+
+	good := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/tcp/1234"),
+		newMultiaddr(t, "/ip6/::1/tcp/1234"),
+		newMultiaddr(t, "/ip4/1.2.3.4/udp/1234/utp"),
+	}
+
+	goodAndBad := append(good, bad...)
+
+	// test filters
+	filter := AddrOverNonLocalIP
+
+	require.Empty(t, FilterAddrs(bad, filter))
+	require.ElementsMatch(t, FilterAddrs(good, filter), good)
+	require.ElementsMatch(t, FilterAddrs(goodAndBad, filter), good)
+}