From c6f32a8c6088d575698b3b111ae052d98286a5e9 Mon Sep 17 00:00:00 2001
From: Vlad <gluk256@gmail.com>
Date: Mon, 18 Dec 2017 17:37:08 +0200
Subject: [PATCH] whisper: respect the PoW requirement

---
 whisper/whisperv6/peer.go      |  2 +-
 whisper/whisperv6/peer_test.go | 48 ++++++++++++++++++++++++----------
 whisper/whisperv6/whisper.go   |  5 +++-
 3 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/whisper/whisperv6/peer.go b/whisper/whisperv6/peer.go
index 29d13bc6ef..f4611b8a71 100644
--- a/whisper/whisperv6/peer.go
+++ b/whisper/whisperv6/peer.go
@@ -156,7 +156,7 @@ func (p *Peer) broadcast() error {
 	var cnt int
 	envelopes := p.host.Envelopes()
 	for _, envelope := range envelopes {
-		if !p.marked(envelope) {
+		if !p.marked(envelope) && envelope.PoW() >= p.powRequirement {
 			err := p2p.Send(p.ws, messagesCode, envelope)
 			if err != nil {
 				return err
diff --git a/whisper/whisperv6/peer_test.go b/whisper/whisperv6/peer_test.go
index 7dd93238c8..40b4cc5ead 100644
--- a/whisper/whisperv6/peer_test.go
+++ b/whisper/whisperv6/peer_test.go
@@ -88,23 +88,31 @@ var sharedKey []byte = []byte("some arbitrary data here")
 var sharedTopic TopicType = TopicType{0xF, 0x1, 0x2, 0}
 var expectedMessage []byte = []byte("per rectum ad astra")
 
-// This test does the following:
-// 1. creates a chain of whisper nodes,
-// 2. installs the filters with shared (predefined) parameters,
-// 3. each node sends a number of random (undecryptable) messages,
-// 4. first node sends one expected (decryptable) message,
-// 5. checks if each node have received and decrypted exactly one message,
-// 6. sends protocol-level messages (powRequirementCode) and checks the new PoW requirement values.
 func TestSimulation(t *testing.T) {
+	// create a chain of whisper nodes,
+	// installs the filters with shared (predefined) parameters
 	initialize(t)
 
+	// each node sends a number of random (undecryptable) messages
 	for i := 0; i < NumNodes; i++ {
 		sendMsg(t, false, i)
 	}
 
+	// node #0 sends one expected (decryptable) message
 	sendMsg(t, true, 0)
-	checkPropagation(t)
+
+	// check if each node have received and decrypted exactly one message
+	checkPropagation(t, true)
+
+	// send protocol-level messages (powRequirementCode) and check the new PoW requirement values
 	powReqExchange(t)
+
+	// node #1 sends one expected (decryptable) message
+	sendMsg(t, true, 1)
+
+	// check if each node (except node #0) have received and decrypted exactly one message
+	checkPropagation(t, false)
+
 	stopServers()
 }
 
@@ -181,18 +189,21 @@ func stopServers() {
 	}
 }
 
-func checkPropagation(t *testing.T) {
+func checkPropagation(t *testing.T, includingNodeZero bool) {
 	if t.Failed() {
 		return
 	}
 
-	const cycle = 100
-	const iterations = 100
+	const cycle = 50
+	const iterations = 200
+
+	first := 0
+	if !includingNodeZero {
+		first = 1
+	}
 
 	for j := 0; j < iterations; j++ {
-		time.Sleep(cycle * time.Millisecond)
-
-		for i := 0; i < NumNodes; i++ {
+		for i := first; i < NumNodes; i++ {
 			f := nodes[i].shh.GetFilter(nodes[i].filerId)
 			if f == nil {
 				t.Fatalf("failed to get filterId %s from node %d.", nodes[i].filerId, i)
@@ -207,9 +218,18 @@ func checkPropagation(t *testing.T) {
 				return
 			}
 		}
+
+		time.Sleep(cycle * time.Millisecond)
 	}
 
 	t.Fatalf("Test was not complete: timeout %d seconds.", iterations*cycle/1000)
+
+	if !includingNodeZero {
+		f := nodes[0].shh.GetFilter(nodes[0].filerId)
+		if f != nil {
+			t.Fatalf("node zero received a message with low PoW.")
+		}
+	}
 }
 
 func validateMail(t *testing.T, index int, mail []*ReceivedMessage) bool {
diff --git a/whisper/whisperv6/whisper.go b/whisper/whisperv6/whisper.go
index ad1897e802..1cdea2aba3 100644
--- a/whisper/whisperv6/whisper.go
+++ b/whisper/whisperv6/whisper.go
@@ -638,7 +638,10 @@ func (wh *Whisper) add(envelope *Envelope) (bool, error) {
 
 	if envelope.PoW() < wh.MinPow() {
 		log.Debug("envelope with low PoW dropped", "PoW", envelope.PoW(), "hash", envelope.Hash().Hex())
-		return false, nil // drop envelope without error
+		return false, nil // drop envelope without error for now
+
+		// after the Status message will include the PoW requirement, it should return an error here:
+		//return false, fmt.Errorf("envelope with low PoW dropped: PoW=%f, hash=[%v]", envelope.PoW(), envelope.Hash().Hex())
 	}
 
 	hash := envelope.Hash()