cosmetic: turn some if-then-else into 'switch'

router/connection.go

@@ -479,23 +479,28 @@ func (conn *LocalConnection) receiveTCP(decoder *gob.Decoder) {
 			// the traffic rather than shutting down.
 			continue
 		}
-		if msg[0] == ProtocolConnectionEstablished {
+		switch msg[0] {
+		case ProtocolConnectionEstablished:
 			// We sent fast heartbeats to the remote peer, which has
 			// now received at least one of them and told us via this
 			// message.  We can now consider the connection as
 			// established from our end.
 			conn.SetEstablished()
-		} else if msg[0] == ProtocolStartFragmentationTest {
+		case ProtocolStartFragmentationTest:
 			conn.Forward(false, &ForwardedFrame{
 				srcPeer: conn.local,
 				dstPeer: conn.remote,
 				frame:   FragTest},
 				nil)
-		} else if msg[0] == ProtocolFragmentationReceived {
+		case ProtocolFragmentationReceived:
 			conn.setStackFrag(true)
-		} else if usingPassword && msg[0] == ProtocolNonce {
-			conn.Decryptor.ReceiveNonce(msg[1:])
-		} else if msg[0] == ProtocolFetchAll {
+		case ProtocolNonce:
+			if usingPassword {
+				conn.Decryptor.ReceiveNonce(msg[1:])
+			} else {
+				conn.log("ignoring unexpected nonce on unencrypted connection")
+			}
+		case ProtocolFetchAll:
 			// There are exactly two messages that relate to topology
 			// updates.
 			//
@@ -517,7 +522,7 @@ func (conn *LocalConnection) receiveTCP(decoder *gob.Decoder) {
 			//  - elements where the payload was older than the
 			//    receiver's version are updated
 			conn.SendTCP(Concat(ProtocolUpdateByte, conn.Router.Peers.EncodeAllPeers()))
-		} else if msg[0] == ProtocolUpdate {
+		case ProtocolUpdate:
 			newUpdate, err := conn.Router.Peers.ApplyUpdate(msg[1:])
 			if _, ok := err.(UnknownPeersError); err != nil && ok {
 				// That update contained a peer we didn't know about;
@@ -533,9 +538,9 @@ func (conn *LocalConnection) receiveTCP(decoder *gob.Decoder) {
 				conn.Router.Routes.Recalculate()
 				conn.Router.Ourself.BroadcastTCP(Concat(ProtocolUpdateByte, newUpdate))
 			}
-		} else if msg[0] == ProtocolPMTUVerified {
+		case ProtocolPMTUVerified:
 			conn.verifyPMTU <- int(binary.BigEndian.Uint16(msg[1:]))
-		} else {
+		default:
 			conn.log("received unknown msg:\n", msg)
 		}
 	}

router/crypto.go

@@ -320,8 +320,9 @@ func (nd *NaClDecryptor) decrypt(buf []byte) ([]byte, error) {
 		usedOffsets = decState.usedOffsets
 	} else {
 		highestOffsetSeen := decState.highestOffsetSeen
-		if offsetNoFlags < (1<<13) && highestOffsetSeen > ((1<<14)+(1<<13)) &&
-			(highestOffsetSeen-offsetNoFlags) > ((1<<14)+(1<<13)) {
+		switch {
+		case offsetNoFlags < (1<<13) && highestOffsetSeen > ((1<<14)+(1<<13)) &&
+			(highestOffsetSeen-offsetNoFlags) > ((1<<14)+(1<<13)):
 			// offset is in the first quarter, highestOffsetSeen is in
 			// the top quarter and under a quarter behind us. We
 			// interpret this as we need to move to the next nonce
@@ -335,29 +336,29 @@ func (nd *NaClDecryptor) decrypt(buf []byte) ([]byte, error) {
 			decState.highestOffsetSeen = offsetNoFlags
 			nonce = decState.nonce
 			usedOffsets = decState.usedOffsets
-		} else if offsetNoFlags > highestOffsetSeen &&
-			(offsetNoFlags-highestOffsetSeen) < (1<<13) {
+		case offsetNoFlags > highestOffsetSeen &&
+			(offsetNoFlags-highestOffsetSeen) < (1<<13):
 			// offset is under a quarter above highestOffsetSeen. This
 			// is ok - maybe some packet loss
 			decState.highestOffsetSeen = offsetNoFlags
 			nonce = decState.nonce
 			usedOffsets = decState.usedOffsets
-		} else if offsetNoFlags <= highestOffsetSeen &&
-			(highestOffsetSeen-offsetNoFlags) < (1<<13) {
+		case offsetNoFlags <= highestOffsetSeen &&
+			(highestOffsetSeen-offsetNoFlags) < (1<<13):
 			// offset is within a quarter of the highest we've
 			// seen. This is ok - just assuming some out-of-order
 			// delivery.
 			nonce = decState.nonce
 			usedOffsets = decState.usedOffsets
-		} else if highestOffsetSeen < (1<<13) && offsetNoFlags > ((1<<14)+(1<<13)) &&
-			(offsetNoFlags-highestOffsetSeen) > ((1<<14)+(1<<13)) {
+		case highestOffsetSeen < (1<<13) && offsetNoFlags > ((1<<14)+(1<<13)) &&
+			(offsetNoFlags-highestOffsetSeen) > ((1<<14)+(1<<13)):
 			// offset is in the last quarter, highestOffsetSeen is in
 			// the first quarter, and offset is under a quarter behind
 			// us. This is ok - as above, just some out of order. But
 			// here it means we're dealing with the previous nonce
 			nonce = decState.previousNonce
 			usedOffsets = decState.previousUsedOffsets
-		} else {
+		default:
 			return nil, fmt.Errorf("Unexpected offset when decrypting UDP packet")
 		}
 	}