swarm/network: Correct neighborhood depth (#18066)

Author: nolash

swarm/network/kademlia.go

@@ -177,7 +177,7 @@ func (k *Kademlia) SuggestPeer() (a *BzzAddr, o int, want bool) {
 	k.lock.Lock()
 	defer k.lock.Unlock()
 	minsize := k.MinBinSize
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	// if there is a callable neighbour within the current proxBin, connect
 	// this makes sure nearest neighbour set is fully connected
 	var ppo int
@@ -308,7 +308,7 @@ func (k *Kademlia) sendNeighbourhoodDepthChange() {
 	// It provides signaling of neighbourhood depth change.
 	// This part of the code is sending new neighbourhood depth to nDepthC if that condition is met.
 	if k.nDepthC != nil {
-		nDepth := k.neighbourhoodDepth()
+		nDepth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 		if nDepth != k.nDepth {
 			k.nDepth = nDepth
 			k.nDepthC <- nDepth
@@ -364,7 +364,7 @@ func (k *Kademlia) EachBin(base []byte, pof pot.Pof, o int, eachBinFunc func(con
 
 	var startPo int
 	var endPo int
-	kadDepth := k.neighbourhoodDepth()
+	kadDepth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 
 	k.conns.EachBin(base, pof, o, func(po, size int, f func(func(val pot.Val, i int) bool) bool) bool {
 		if startPo > 0 && endPo != k.MaxProxDisplay {
@@ -398,7 +398,7 @@ func (k *Kademlia) eachConn(base []byte, o int, f func(*Peer, int, bool) bool) {
 	if len(base) == 0 {
 		base = k.base
 	}
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	k.conns.EachNeighbour(base, pof, func(val pot.Val, po int) bool {
 		if po > o {
 			return true
@@ -420,7 +420,7 @@ func (k *Kademlia) eachAddr(base []byte, o int, f func(*BzzAddr, int, bool) bool
 	if len(base) == 0 {
 		base = k.base
 	}
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	k.addrs.EachNeighbour(base, pof, func(val pot.Val, po int) bool {
 		if po > o {
 			return true
@@ -429,26 +429,72 @@ func (k *Kademlia) eachAddr(base []byte, o int, f func(*BzzAddr, int, bool) bool
 	})
 }
 
-// neighbourhoodDepth returns the proximity order that defines the distance of
-// the nearest neighbour set with cardinality >= MinProxBinSize
-// if there is altogether less than MinProxBinSize peers it returns 0
 func (k *Kademlia) NeighbourhoodDepth() (depth int) {
 	k.lock.RLock()
 	defer k.lock.RUnlock()
-	return k.neighbourhoodDepth()
+	return depthForPot(k.conns, k.MinProxBinSize, k.base)
 }
 
-func (k *Kademlia) neighbourhoodDepth() (depth int) {
-	if k.conns.Size() < k.MinProxBinSize {
+// depthForPot returns the proximity order that defines the distance of
+// the nearest neighbour set with cardinality >= MinProxBinSize
+// if there is altogether less than MinProxBinSize peers it returns 0
+// caller must hold the lock
+func depthForPot(p *pot.Pot, minProxBinSize int, pivotAddr []byte) (depth int) {
+	if p.Size() <= minProxBinSize {
 		return 0
 	}
+
+	// total number of peers in iteration
 	var size int
+
+	// true if iteration has all prox peers
+	var b bool
+
+	// last po recorded in iteration
+	var lastPo int
+
 	f := func(v pot.Val, i int) bool {
+		// po == 256 means that addr is the pivot address(self)
+		if i == 256 {
+			return true
+		}
 		size++
-		depth = i
-		return size < k.MinProxBinSize
+
+		// this means we have all nn-peers.
+		// depth is by default set to the bin of the farthest nn-peer
+		if size == minProxBinSize {
+			b = true
+			depth = i
+			return true
+		}
+
+		// if there are empty bins between farthest nn and current node,
+		// the depth should recalculated to be
+		// the farthest of those empty bins
+		//
+		// 0   abac ccde
+		// 1   2a2a
+		// 2   589f       <--- nearest non-nn
+		// ============ DEPTH 3  ===========
+		// 3              <--- don't count as empty bins
+		// 4              <--- don't count as empty bins
+		// 5  cbcb cdcd    <---- furthest nn
+		// 6  a1a2 b3c4
+		if b && i < depth {
+			depth = i + 1
+			lastPo = i
+			return false
+		}
+		lastPo = i
+		return true
+	}
+	p.EachNeighbour(pivotAddr, pof, f)
+
+	// cover edge case where more than one farthest nn
+	// AND we only have nn-peers
+	if lastPo == depth {
+		depth = 0
 	}
-	k.conns.EachNeighbour(k.base, pof, f)
 	return depth
 }
 
@@ -508,7 +554,7 @@ func (k *Kademlia) string() string {
 	liverows := make([]string, k.MaxProxDisplay)
 	peersrows := make([]string, k.MaxProxDisplay)
 
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	rest := k.conns.Size()
 	k.conns.EachBin(k.base, pof, 0, func(po, size int, f func(func(val pot.Val, i int) bool) bool) bool {
 		var rowlen int
@@ -578,6 +624,7 @@ type PeerPot struct {
 // as hexadecimal representations of the address.
 // used for testing only
 func NewPeerPotMap(kadMinProxSize int, addrs [][]byte) map[string]*PeerPot {
+
 	// create a table of all nodes for health check
 	np := pot.NewPot(nil, 0)
 	for _, addr := range addrs {
@@ -586,34 +633,47 @@ func NewPeerPotMap(kadMinProxSize int, addrs [][]byte) map[string]*PeerPot {
 	ppmap := make(map[string]*PeerPot)
 
 	for i, a := range addrs {
-		pl := 256
-		prev := 256
+
+		// actual kademlia depth
+		depth := depthForPot(np, kadMinProxSize, a)
+
+		// upon entering a new iteration
+		// this will hold the value the po should be
+		// if it's one higher than the po in the last iteration
+		prevPo := 256
+
+		// all empty bins which are outside neighbourhood depth
 		var emptyBins []int
+
+		// all nn-peers
 		var nns [][]byte
-		np.EachNeighbour(addrs[i], pof, func(val pot.Val, po int) bool {
-			a := val.([]byte)
+
+		np.EachNeighbour(a, pof, func(val pot.Val, po int) bool {
+			addr := val.([]byte)
+			// po == 256 means that addr is the pivot address(self)
 			if po == 256 {
 				return true
 			}
-			if pl == 256 || pl == po {
-				nns = append(nns, a)
-			}
-			if pl == 256 && len(nns) >= kadMinProxSize {
-				pl = po
-				prev = po
+
+			// iterate through the neighbours, going from the closest to the farthest
+			// we calculate the nearest neighbours that should be in the set
+			// depth in this case equates to:
+			// 1.  Within all bins that are higher or equal than depth there are
+			//     at least minProxBinSize peers connected
+			// 2.  depth-1 bin is not empty
+			if po >= depth {
+				nns = append(nns, addr)
+				prevPo = depth - 1
+				return true
 			}
-			if prev < pl {
-				for j := prev; j > po; j-- {
-					emptyBins = append(emptyBins, j)
-				}
+			for j := prevPo; j > po; j-- {
+				emptyBins = append(emptyBins, j)
 			}
-			prev = po - 1
+			prevPo = po - 1
 			return true
 		})
-		for j := prev; j >= 0; j-- {
-			emptyBins = append(emptyBins, j)
-		}
-		log.Trace(fmt.Sprintf("%x NNS: %s", addrs[i][:4], LogAddrs(nns)))
+
+		log.Trace(fmt.Sprintf("%x NNS: %s, emptyBins: %s", addrs[i][:4], LogAddrs(nns), logEmptyBins(emptyBins)))
 		ppmap[common.Bytes2Hex(a)] = &PeerPot{nns, emptyBins}
 	}
 	return ppmap
@@ -628,7 +688,7 @@ func (k *Kademlia) saturation(n int) int {
 		prev++
 		return prev == po && size >= n
 	})
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	if depth < prev {
 		return depth
 	}
@@ -641,8 +701,11 @@ func (k *Kademlia) full(emptyBins []int) (full bool) {
 	prev := 0
 	e := len(emptyBins)
 	ok := true
-	depth := k.neighbourhoodDepth()
+	depth := depthForPot(k.conns, k.MinProxBinSize, k.base)
 	k.conns.EachBin(k.base, pof, 0, func(po, _ int, _ func(func(val pot.Val, i int) bool) bool) bool {
+		if po >= depth {
+			return false
+		}
 		if prev == depth+1 {
 			return true
 		}

swarm/network/kademlia_test.go

@@ -25,6 +25,9 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/protocols"
 	"github.com/ethereum/go-ethereum/swarm/pot"
 )
 
@@ -73,6 +76,76 @@ func Register(k *Kademlia, regs ...string) {
 	}
 }
 
+// tests the validity of neighborhood depth calculations
+//
+// in particular, it tests that if there are one or more consecutive
+// empty bins above the farthest "nearest neighbor-peer" then
+// the depth should be set at the farthest of those empty bins
+//
+// TODO: Make test adapt to change in MinProxBinSize
+func TestNeighbourhoodDepth(t *testing.T) {
+	baseAddressBytes := RandomAddr().OAddr
+	kad := NewKademlia(baseAddressBytes, NewKadParams())
+
+	baseAddress := pot.NewAddressFromBytes(baseAddressBytes)
+
+	closerAddress := pot.RandomAddressAt(baseAddress, 7)
+	closerPeer := newTestDiscoveryPeer(closerAddress, kad)
+	kad.On(closerPeer)
+	depth := kad.NeighbourhoodDepth()
+	if depth != 0 {
+		t.Fatalf("expected depth 0, was %d", depth)
+	}
+
+	sameAddress := pot.RandomAddressAt(baseAddress, 7)
+	samePeer := newTestDiscoveryPeer(sameAddress, kad)
+	kad.On(samePeer)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 0 {
+		t.Fatalf("expected depth 0, was %d", depth)
+	}
+
+	midAddress := pot.RandomAddressAt(baseAddress, 4)
+	midPeer := newTestDiscoveryPeer(midAddress, kad)
+	kad.On(midPeer)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 5 {
+		t.Fatalf("expected depth 5, was %d", depth)
+	}
+
+	kad.Off(midPeer)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 0 {
+		t.Fatalf("expected depth 0, was %d", depth)
+	}
+
+	fartherAddress := pot.RandomAddressAt(baseAddress, 1)
+	fartherPeer := newTestDiscoveryPeer(fartherAddress, kad)
+	kad.On(fartherPeer)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 2 {
+		t.Fatalf("expected depth 2, was %d", depth)
+	}
+
+	midSameAddress := pot.RandomAddressAt(baseAddress, 4)
+	midSamePeer := newTestDiscoveryPeer(midSameAddress, kad)
+	kad.Off(closerPeer)
+	kad.On(midPeer)
+	kad.On(midSamePeer)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 2 {
+		t.Fatalf("expected depth 2, was %d", depth)
+	}
+
+	kad.Off(fartherPeer)
+	log.Trace(kad.string())
+	time.Sleep(time.Millisecond)
+	depth = kad.NeighbourhoodDepth()
+	if depth != 0 {
+		t.Fatalf("expected depth 0, was %d", depth)
+	}
+}
+
 func testSuggestPeer(k *Kademlia, expAddr string, expPo int, expWant bool) error {
 	addr, o, want := k.SuggestPeer()
 	if binStr(addr) != expAddr {
@@ -376,7 +449,7 @@ func TestKademliaHiveString(t *testing.T) {
 	Register(k, "10000000", "10000001")
 	k.MaxProxDisplay = 8
 	h := k.String()
-	expH := "\n=========================================================================\nMon Feb 27 12:10:28 UTC 2017 KΛÐΞMLIΛ hive: queen's address: 000000\npopulation: 2 (4), MinProxBinSize: 2, MinBinSize: 1, MaxBinSize: 4\n000  0                              |  2 8100 (0) 8000 (0)\n============ DEPTH: 1 ==========================================\n001  1 4000                         |  1 4000 (0)\n002  1 2000                         |  1 2000 (0)\n003  0                              |  0\n004  0                              |  0\n005  0                              |  0\n006  0                              |  0\n007  0                              |  0\n========================================================================="
+	expH := "\n=========================================================================\nMon Feb 27 12:10:28 UTC 2017 KΛÐΞMLIΛ hive: queen's address: 000000\npopulation: 2 (4), MinProxBinSize: 2, MinBinSize: 1, MaxBinSize: 4\n============ DEPTH: 0 ==========================================\n000  0                              |  2 8100 (0) 8000 (0)\n001  1 4000                         |  1 4000 (0)\n002  1 2000                         |  1 2000 (0)\n003  0                              |  0\n004  0                              |  0\n005  0                              |  0\n006  0                              |  0\n007  0                              |  0\n========================================================================="
 	if expH[104:] != h[104:] {
 		t.Fatalf("incorrect hive output. expected %v, got %v", expH, h)
 	}
@@ -644,3 +717,17 @@ func TestKademliaCase5(t *testing.T) {
 		"78fafa0809929a1279ece089a51d12457c2d8416dff859aeb2ccc24bb50df5ec", "1dd39b1257e745f147cbbc3cadd609ccd6207c41056dbc4254bba5d2527d3ee5", "5f61dd66d4d94aec8fcc3ce0e7885c7edf30c43143fa730e2841c5d28e3cd081", "8aa8b0472cb351d967e575ad05c4b9f393e76c4b01ef4b3a54aac5283b78abc9", "4502f385152a915b438a6726ce3ea9342e7a6db91a23c2f6bee83a885ed7eb82", "718677a504249db47525e959ef1784bed167e1c46f1e0275b9c7b588e28a3758", "7c54c6ed1f8376323896ed3a4e048866410de189e9599dd89bf312ca4adb96b5", "18e03bd3378126c09e799a497150da5c24c895aedc84b6f0dbae41fc4bac081a", "23db76ac9e6e58d9f5395ca78252513a7b4118b4155f8462d3d5eec62486cadc", "40ae0e8f065e96c7adb7fa39505136401f01780481e678d718b7f6dbb2c906ec", "c1539998b8bae19d339d6bbb691f4e9daeb0e86847545229e80fe0dffe716e92", "ed139d73a2699e205574c08722ca9f030ad2d866c662f1112a276b91421c3cb9", "5bdb19584b7a36d09ca689422ef7e6bb681b8f2558a6b2177a8f7c812f631022", "636c9de7fe234ffc15d67a504c69702c719f626c17461d3f2918e924cd9d69e2", "de4455413ff9335c440d52458c6544191bd58a16d85f700c1de53b62773064ea", "de1963310849527acabc7885b6e345a56406a8f23e35e436b6d9725e69a79a83", "a80a50a467f561210a114cba6c7fb1489ed43a14d61a9edd70e2eb15c31f074d", "7804f12b8d8e6e4b375b242058242068a3809385e05df0e64973cde805cf729c", "60f9aa320c02c6f2e6370aa740cf7cea38083fa95fca8c99552cda52935c1520", "d8da963602390f6c002c00ce62a84b514edfce9ebde035b277a957264bb54d21", "8463d93256e026fe436abad44697152b9a56ac8e06a0583d318e9571b83d073c", "9a3f78fcefb9a05e40a23de55f6153d7a8b9d973ede43a380bf46bb3b3847de1", "e3bb576f4b3760b9ca6bff59326f4ebfc4a669d263fb7d67ab9797adea54ed13", "4d5cdbd6dcca5bdf819a0fe8d175dc55cc96f088d37462acd5ea14bc6296bdbe", "5a0ed28de7b5258c727cb85447071c74c00a5fbba9e6bc0393bc51944d04ab2a", "61e4ddb479c283c638f4edec24353b6cc7a3a13b930824aad016b0996ca93c47", "7e3610868acf714836cafaaa7b8c009a9ac6e3a6d443e5586cf661530a204ee2", "d74b244d4345d2c86e30a097105e4fb133d53c578320285132a952cdaa64416e", "cfeed57d0f935bfab89e3f630a7c97e0b1605f0724d85a008bbfb92cb47863a8", "580837af95055670e20d494978f60c7f1458dc4b9e389fc7aa4982b2aca3bce3", "df55c0c49e6c8a83d82dfa1c307d3bf6a20e18721c80d8ec4f1f68dc0a137ced", "5f149c51ce581ba32a285439a806c063ced01ccd4211cd024e6a615b8f216f95", "1eb76b00aeb127b10dd1b7cd4c3edeb4d812b5a658f0feb13e85c4d2b7c6fe06", "7a56ba7c3fb7cbfb5561a46a75d95d7722096b45771ec16e6fa7bbfab0b35dfe", "4bae85ad88c28470f0015246d530adc0cd1778bdd5145c3c6b538ee50c4e04bd", "afd1892e2a7145c99ec0ebe9ded0d3fec21089b277a68d47f45961ec5e39e7e0", "953138885d7b36b0ef79e46030f8e61fd7037fbe5ce9e0a94d728e8c8d7eab86", "de761613ef305e4f628cb6bf97d7b7dc69a9d513dc233630792de97bcda777a6", "3f3087280063d09504c084bbf7fdf984347a72b50d097fd5b086ffabb5b3fb4c", "7d18a94bb1ebfdef4d3e454d2db8cb772f30ca57920dd1e402184a9e598581a0", "a7d6fbdc9126d9f10d10617f49fb9f5474ffe1b229f76b7dd27cebba30eccb5d", "fad0246303618353d1387ec10c09ee991eb6180697ed3470ed9a6b377695203d", "1cf66e09ea51ee5c23df26615a9e7420be2ac8063f28f60a3bc86020e94fe6f3", "8269cdaa153da7c358b0b940791af74d7c651cd4d3f5ed13acfe6d0f2c539e7f", "90d52eaaa60e74bf1c79106113f2599471a902d7b1c39ac1f55b20604f453c09", "9788fd0c09190a3f3d0541f68073a2f44c2fcc45bb97558a7c319f36c25a75b3", "10b68fc44157ecfdae238ee6c1ce0333f906ad04d1a4cb1505c8e35c3c87fbb0", "e5284117fdf3757920475c786e0004cb00ba0932163659a89b36651a01e57394", "403ad51d911e113dcd5f9ff58c94f6d278886a2a4da64c3ceca2083282c92de3",
 	)
 }
+
+func newTestDiscoveryPeer(addr pot.Address, kad *Kademlia) *Peer {
+	rw := &p2p.MsgPipeRW{}
+	p := p2p.NewPeer(enode.ID{}, "foo", []p2p.Cap{})
+	pp := protocols.NewPeer(p, rw, &protocols.Spec{})
+	bp := &BzzPeer{
+		Peer: pp,
+		BzzAddr: &BzzAddr{
+			OAddr: addr.Bytes(),
+			UAddr: []byte(fmt.Sprintf("%x", addr[:])),
+		},
+	}
+	return NewPeer(bp, kad)
+}

swarm/network/simulation/example_test.go

@@ -33,6 +33,10 @@ import (
 // BucketKeyKademlia key. This allows to use WaitTillHealthy to block until
 // all nodes have the their Kadmlias healthy.
 func ExampleSimulation_WaitTillHealthy() {
+
+	log.Error("temporarily disabled as simulations.WaitTillHealthy cannot be trusted")
+	return
+
 	sim := simulation.New(map[string]simulation.ServiceFunc{
 		"bzz": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
 			addr := network.NewAddr(ctx.Config.Node())

swarm/network/simulation/kademlia.go

@@ -33,6 +33,7 @@ var BucketKeyKademlia BucketKey = "kademlia"
 
 // WaitTillHealthy is blocking until the health of all kademlias is true.
 // If error is not nil, a map of kademlia that was found not healthy is returned.
+// TODO: Check correctness since change in kademlia depth calculation logic
 func (s *Simulation) WaitTillHealthy(ctx context.Context, kadMinProxSize int) (ill map[enode.ID]*network.Kademlia, err error) {
 	// Prepare PeerPot map for checking Kademlia health
 	var ppmap map[string]*network.PeerPot

swarm/network/simulation/kademlia_test.go

@@ -28,6 +28,7 @@ import (
 )
 
 func TestWaitTillHealthy(t *testing.T) {
+
 	sim := New(map[string]ServiceFunc{
 		"bzz": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
 			addr := network.NewAddr(ctx.Config.Node())

swarm/network/stream/delivery_test.go

@@ -453,6 +453,8 @@ func TestDeliveryFromNodes(t *testing.T) {
 }
 
 func testDeliveryFromNodes(t *testing.T, nodes, conns, chunkCount int, skipCheck bool) {
+
+	t.Skip("temporarily disabled as simulations.WaitTillHealthy cannot be trusted")
 	sim := simulation.New(map[string]simulation.ServiceFunc{
 		"streamer": func(ctx *adapters.ServiceContext, bucket *sync.Map) (s node.Service, cleanup func(), err error) {
 			node := ctx.Config.Node()

swarm/network/stream/intervals_test.go

@@ -52,6 +52,8 @@ func TestIntervalsLiveAndHistory(t *testing.T) {
 }
 
 func testIntervals(t *testing.T, live bool, history *Range, skipCheck bool) {
+
+	t.Skip("temporarily disabled as simulations.WaitTillHealthy cannot be trusted")
 	nodes := 2
 	chunkCount := dataChunkCount
 	externalStreamName := "externalStream"

swarm/network/stream/snapshot_retrieval_test.go

@@ -246,6 +246,7 @@ simulation's `action` function.
 The snapshot should have 'streamer' in its service list.
 */
 func runRetrievalTest(chunkCount int, nodeCount int) error {
+
 	sim := simulation.New(retrievalSimServiceMap)
 	defer sim.Close()