Refactor send in cmix to have sendWithCompiler as its base

cmix/client.go

@@ -189,9 +189,15 @@ func (c *client) initialize(ndf *ndf.NetworkDefinition) error {
 	// Set up critical message tracking (sendCmix only)
 	critSender := func(msg format.Message, recipient *id.ID, params CMIXParams,
 	) (id.Round, ephemeral.Id, error) {
-		return sendCmixHelper(c.Sender, msg, recipient, params, c.instance,
+		// TODO: Does this need to be reworked to take in a message compiler?  This has ramifications down the stack in critical messaging
+		compiler := func(round id.Round) (format.Message, error) {
+			return msg, nil
+		}
+		rid, eid, _, sendErr := sendCmixHelper(c.Sender, compiler, recipient, params, c.instance,
 			c.session.GetCmixGroup(), c.Registrar, c.rng, c.events,
 			c.session.GetTransmissionID(), c.comms)
+		return rid, eid, sendErr
+
 	}
 
 	c.crit = newCritical(c.session.GetKV(), c.Monitor,

cmix/sendCmix.go

@@ -56,14 +56,29 @@ import (
 // WARNING: Do not roll your own crypto.
 func (c *client) Send(recipient *id.ID, fingerprint format.Fingerprint,
 	service message.Service, payload, mac []byte, cmixParams CMIXParams) (
+	id.Round, ephemeral.Id, error) {
+	compiler := func(rid id.Round) (format.Fingerprint, message.Service, []byte, []byte) {
+		return fingerprint, service, payload, mac
+	}
+	return c.SendWithCompiler(recipient, compiler, cmixParams)
+}
+
+type Compiler func(rid id.Round) (fingerprint format.Fingerprint, service message.Service, payload, mac []byte)
+
+type messageCompiler func(rid id.Round) (format.Message, error)
+
+func (c *client) SendWithCompiler(recipient *id.ID, compiler Compiler, cmixParams CMIXParams) (
 	id.Round, ephemeral.Id, error) {
 	if !c.Monitor.IsHealthy() {
 		return 0, ephemeral.Id{}, errors.New(
 			"Cannot send cmix message when the network is not healthy")
 	}
 
+	compilerFunc := func(rid id.Round) (format.Message, error) {
+		fingerprint, service, payload, mac := compiler(rid)
+
 		if len(payload) != c.maxMsgLen {
-		return 0, ephemeral.Id{}, errors.Errorf(
+			return format.Message{}, errors.Errorf(
 				"bad message length (%d, need %d)",
 				len(payload), c.maxMsgLen)
 		}
@@ -82,8 +97,10 @@ func (c *client) Send(recipient *id.ID, fingerprint format.Fingerprint,
 		if cmixParams.Critical {
 			c.crit.AddProcessing(msg, recipient, cmixParams)
 		}
+		return msg, nil
+	}
 
-	rid, ephID, rtnErr := sendCmixHelper(c.Sender, msg, recipient, cmixParams,
+	rid, ephID, msg, rtnErr := sendCmixHelper(c.Sender, compilerFunc, recipient, cmixParams,
 		c.instance, c.session.GetCmixGroup(), c.Registrar, c.rng, c.events,
 		c.session.GetTransmissionID(), c.comms)
 
@@ -104,10 +121,10 @@ func (c *client) Send(recipient *id.ID, fingerprint format.Fingerprint,
 // If the message is successfully sent, the ID of the round sent it is returned,
 // which can be registered with the network instance to get a callback on its
 // status.
-func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
+func sendCmixHelper(sender gateway.Sender, msgCompiler messageCompiler, recipient *id.ID,
 	cmixParams CMIXParams, instance *network.Instance, grp *cyclic.Group,
 	nodes nodes.Registrar, rng *fastRNG.StreamGenerator, events event.Reporter,
-	senderId *id.ID, comms SendCmixCommsInterface) (id.Round, ephemeral.Id, error) {
+	senderId *id.ID, comms SendCmixCommsInterface) (id.Round, ephemeral.Id, format.Message, error) {
 
 	timeStart := netTime.Now()
 	maxTimeout := sender.GetHostParams().SendTimeout
@@ -120,15 +137,11 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 	}
 
 	jww.INFO.Printf("[Send-%s] Looking for round to send cMix message to "+
-		"%s (msgDigest: %s)", cmixParams.DebugTag, recipient, msg.Digest())
+		"%s", cmixParams.DebugTag, recipient)
 
 	stream := rng.GetStream()
 	defer stream.Close()
 
-	// Flip leading bits randomly to thwart a tagging attack.
-	// See cmix.SetGroupBits for more info.
-	cmix.SetGroupBits(msg, grp, stream)
-
 	for numRoundTries := uint(0); numRoundTries < cmixParams.RoundTries; numRoundTries++ {
 		elapsed := netTime.Since(timeStart)
 		jww.TRACE.Printf("[Send-%s] try %d, elapsed: %s",
@@ -136,15 +149,15 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 
 		if elapsed > cmixParams.Timeout {
 			jww.INFO.Printf("[Send-%s] No rounds to send to %s "+
-				"(msgDigest: %s) were found before timeout %s",
-				cmixParams.DebugTag, recipient, msg.Digest(), cmixParams.Timeout)
-			return 0, ephemeral.Id{}, errors.New("Sending cmix message timed out")
+				"were found before timeout %s",
+				cmixParams.DebugTag, recipient, cmixParams.Timeout)
+			return 0, ephemeral.Id{}, format.Message{}, errors.New("Sending cmix message timed out")
 		}
 
 		if numRoundTries > 0 {
 			jww.INFO.Printf("[Send-%s] Attempt %d to find round to send "+
-				"message to %s (msgDigest: %s)", cmixParams.DebugTag,
-				numRoundTries+1, recipient, msg.Digest())
+				"message to %s", cmixParams.DebugTag,
+				numRoundTries+1, recipient)
 		}
 
 		// Find the best round to send to, excluding attempted rounds
@@ -152,8 +165,8 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 		bestRound, err := instance.GetWaitingRounds().GetUpcomingRealtime(
 			remainingTime, attempted, sendTimeBuffer)
 		if err != nil {
-			jww.WARN.Printf("[Send-%s] Failed to GetUpcomingRealtime "+
-				"(msgDigest: %s): %+v", cmixParams.DebugTag, msg.Digest(), err)
+			jww.WARN.Printf("[Send-%s] Failed to GetUpcomingRealtime: "+
+				"%+v", cmixParams.DebugTag, err)
 		}
 
 		if bestRound == nil {
@@ -185,6 +198,16 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 			continue
 		}
 
+		msg, err := msgCompiler(id.Round(bestRound.ID))
+		if err != nil {
+			jww.ERROR.Printf("Failed to compile message: %+v", err)
+			return 0, ephemeral.Id{}, format.Message{}, err
+		}
+
+		// Flip leading bits randomly to thwart a tagging attack.
+		// See cmix.SetGroupBits for more info.
+		cmix.SetGroupBits(msg, grp, stream)
+
 		// Retrieve host and key information from round
 		firstGateway, roundKeys, err := processRound(
 			nodes, bestRound, recipient.String(), msg.Digest())
@@ -201,7 +224,7 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 		wrappedMsg, encMsg, ephID, err := buildSlotMessage(msg, recipient,
 			firstGateway, stream, senderId, bestRound, roundKeys)
 		if err != nil {
-			return 0, ephemeral.Id{}, err
+			return 0, ephemeral.Id{}, format.Message{}, err
 		}
 
 		jww.INFO.Printf("[Send-%s] Sending to EphID %d (%s), on round %d "+
@@ -251,7 +274,7 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 
 		// Exit if the thread has been stopped
 		if stoppable.CheckErr(err) {
-			return 0, ephemeral.Id{}, err
+			return 0, ephemeral.Id{}, format.Message{}, err
 		}
 
 		// If the comm errors or the message fails to send, continue retrying
@@ -260,7 +283,7 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 				jww.ERROR.Printf("[Send-%s] SendCmix failed to send to "+
 					"EphID %d (%s) on round %d: %+v", cmixParams.DebugTag,
 					ephID.Int64(), recipient, bestRound.ID, err)
-				return 0, ephemeral.Id{}, err
+				return 0, ephemeral.Id{}, format.Message{}, err
 			}
 
 			jww.ERROR.Printf("[Send-%s] SendCmix failed to send to "+
@@ -280,7 +303,7 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 			jww.INFO.Print(m)
 			events.Report(1, "MessageSend", "Metric", m)
 
-			return id.Round(bestRound.ID), ephID, nil
+			return id.Round(bestRound.ID), ephID, msg, nil
 		} else {
 			jww.FATAL.Panicf("[Send-%s] Gateway %s returned no error, "+
 				"but failed to accept message when sending to EphID %d (%s) "+
@@ -289,6 +312,6 @@ func sendCmixHelper(sender gateway.Sender, msg format.Message, recipient *id.ID,
 		}
 
 	}
-	return 0, ephemeral.Id{},
+	return 0, ephemeral.Id{}, format.Message{},
 		errors.New("failed to send the message, unknown error")
 }