go test: add ICMP ping

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

diff --git a/contrib/external-tests/go/main.go b/contrib/external-tests/go/main.go
index 16632bbaa7bca2bcb6bee29a57017e8f3d5b1193..68447feb8802b32a642e00518c253a1fd55e048a 100644 (file)
--- a/contrib/external-tests/go/main.go
+++ b/contrib/external-tests/go/main.go
@@ -12,6 +12,8 @@ import (
 
        "github.com/dchest/blake2s"
        "github.com/titanous/noise"
+       "golang.org/x/net/icmp"
+       "golang.org/x/net/ipv4"
 )
 
 func main() {
@@ -36,6 +38,7 @@ func main() {
        }
        defer conn.Close()
 
+       // write handshake initiation packet
        now := time.Now()
        tai64n := make([]byte, 12)
        binary.BigEndian.PutUint64(tai64n[:], uint64(now.Unix()))
@@ -53,6 +56,7 @@ func main() {
                log.Fatalf("error writing initiation packet: %s", err)
        }
 
+       // read handshake response packet
        responsePacket := make([]byte, 89)
        n, err := conn.Read(responsePacket)
        if err != nil {
@@ -69,7 +73,7 @@ func main() {
        if ourIndex != 28 {
                log.Fatalf("response packet index wrong: want %d, got %d", 28, ourIndex)
        }
-       payload, sendCipher, _, err := hs.ReadMessage(nil, responsePacket[9:57])
+       payload, sendCipher, receiveCipher, err := hs.ReadMessage(nil, responsePacket[9:57])
        if err != nil {
                log.Fatalf("error reading handshake message: %s", err)
        }
@@ -77,12 +81,64 @@ func main() {
                log.Fatalf("unexpected payload: %x", payload)
        }
 
-       keepalivePacket := make([]byte, 13)
-       keepalivePacket[0] = 4 // Type: Data
-       binary.LittleEndian.PutUint32(keepalivePacket[1:], theirIndex)
-       binary.LittleEndian.PutUint64(keepalivePacket[5:], 0) // Nonce
-       keepalivePacket = sendCipher.Encrypt(keepalivePacket, nil, nil)
-       if _, err := conn.Write(keepalivePacket); err != nil {
-               log.Fatalf("error writing keepalive packet: %s", err)
+       // write ICMP Echo packet
+       pingMessage, _ := (&icmp.Message{
+               Type: ipv4.ICMPTypeEcho,
+               Body: &icmp.Echo{
+                       ID:   1,
+                       Seq:  1,
+                       Data: []byte("WireGuard"),
+               },
+       }).Marshal(nil)
+       pingHeader, err := (&ipv4.Header{
+               Version:  ipv4.Version,
+               Len:      ipv4.HeaderLen,
+               TotalLen: ipv4.HeaderLen + len(pingMessage),
+               Protocol: 1, // ICMP
+               TTL:      2,
+               Checksum: 0xa15b, // the packet is always the same, hard-code checksum
+               Src:      net.IPv4(10, 189, 129, 2),
+               Dst:      net.IPv4(10, 189, 129, 1),
+       }).Marshal()
+       binary.BigEndian.PutUint16(pingHeader[2:], uint16(ipv4.HeaderLen+len(pingMessage))) // fix the length endianness on BSDs
+       if err != nil {
+               panic(err)
+       }
+       pingPacket := make([]byte, 13)
+       pingPacket[0] = 4 // Type: Data
+       binary.LittleEndian.PutUint32(pingPacket[1:], theirIndex)
+       binary.LittleEndian.PutUint64(pingPacket[5:], 0) // Nonce
+       pingPacket = sendCipher.Encrypt(pingPacket, nil, append(pingHeader, pingMessage...))
+       if _, err := conn.Write(pingPacket); err != nil {
+               log.Fatalf("error writing ping message: %s", err)
+       }
+
+       // read ICMP Echo Reply packet
+       replyPacket := make([]byte, 128)
+       n, err = conn.Read(replyPacket)
+       if err != nil {
+               log.Fatalf("error reading ping reply message: %s", err)
+       }
+       replyPacket = replyPacket[:n]
+       if replyPacket[0] != 4 { // Type: Data
+               log.Fatalf("unexpected reply packet type: %d", replyPacket[0])
+       }
+       replyPacket, err = receiveCipher.Decrypt(nil, nil, replyPacket[13:])
+       if err != nil {
+               log.Fatalf("error decrypting reply packet: %s", err)
+       }
+       replyHeaderLen := int(replyPacket[0]&0x0f) << 2
+       replyLen := binary.BigEndian.Uint16(replyPacket[2:])
+       replyMessage, err := icmp.ParseMessage(1, replyPacket[replyHeaderLen:replyLen])
+       if err != nil {
+               log.Fatalf("error parsing echo: %s", err)
+       }
+       echo, ok := replyMessage.Body.(*icmp.Echo)
+       if !ok {
+               log.Fatalf("unexpected reply body type %T", replyMessage.Body)
+       }
+
+       if echo.ID != 1 || echo.Seq != 1 || string(echo.Data) != "WireGuard" {
+               log.Fatalf("incorrect echo response: %#v", echo)
        }
 }