webrtc: fix ufrag prefix for dialing (#2832)

libp2p · Jun 12, 2024 · 398c0b4 · 398c0b4
1 parent 1be87de
commit 398c0b4
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/p2p/transport/webrtc/transport.go b/p2p/transport/webrtc/transport.go
@@ -415,15 +415,17 @@ func genUfrag() string {
 		uFragAlphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
 		uFragPrefix   = "libp2p+webrtc+v1/"
 		uFragIdLength = 32
-		uFragIdOffset = len(uFragPrefix)
-		uFragLength   = uFragIdOffset + uFragIdLength
+		uFragLength   = len(uFragPrefix) + uFragIdLength
 	)
 
 	seed := [8]byte{}
 	rand.Read(seed[:])
 	r := mrand.New(mrand.NewSource(binary.BigEndian.Uint64(seed[:])))
 	b := make([]byte, uFragLength)
-	for i := uFragIdOffset; i < uFragLength; i++ {
+	for i := 0; i < len(uFragPrefix); i++ {
+		b[i] = uFragPrefix[i]
+	}
+	for i := len(uFragPrefix); i < uFragLength; i++ {
 		b[i] = uFragAlphabet[r.Intn(len(uFragAlphabet))]
 	}
 	return string(b)

diff --git a/p2p/transport/webrtc/transport_test.go b/p2p/transport/webrtc/transport_test.go
@@ -860,3 +860,10 @@ func TestMaxInFlightRequests(t *testing.T) {
 	require.Equal(t, count, int(success.Load()), "expected exactly 3 dial successes")
 	require.Equal(t, 1, int(fails.Load()), "expected exactly 1 dial failure")
 }
+
+func TestGenUfrag(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		s := genUfrag()
+		require.True(t, strings.HasPrefix(s, "libp2p+webrtc+v1/"))
+	}
+}