les, light: fix CHT trie retrievals (#16039)

* les, light: fix CHT trie retrievals

* les, light: minor polishes, test remote CHT retrievals

* les, light: deterministic nodeset rlp, bloombits test skeleton

* les: add an event emission to the les bloombits test

* les: drop dead tester code

4 files changed, 36 insertions, 24 deletions

diff --git a/light/lightchain.go b/light/lightchain.go
index bc88aeb48..181a1c2a6 100644
--- a/light/lightchain.go
+++ b/light/lightchain.go
@@ -127,7 +127,7 @@ func (self *LightChain) addTrustedCheckpoint(cp trustedCheckpoint) {
 	if self.odr.BloomIndexer() != nil {
 		self.odr.BloomIndexer().AddKnownSectionHead(cp.sectionIdx, cp.sectionHead)
 	}
-	log.Info("Added trusted checkpoint", "chain", cp.name, "block", (cp.sectionIdx+1)*ChtFrequency-1, "hash", cp.sectionHead)
+	log.Info("Added trusted checkpoint", "chain", cp.name, "block", (cp.sectionIdx+1)*CHTFrequencyClient-1, "hash", cp.sectionHead)
 }
 
 func (self *LightChain) getProcInterrupt() bool {
@@ -453,8 +453,8 @@ func (self *LightChain) SyncCht(ctx context.Context) bool {
 	}
 	headNum := self.CurrentHeader().Number.Uint64()
 	chtCount, _, _ := self.odr.ChtIndexer().Sections()
-	if headNum+1 < chtCount*ChtFrequency {
-		num := chtCount*ChtFrequency - 1
+	if headNum+1 < chtCount*CHTFrequencyClient {
+		num := chtCount*CHTFrequencyClient - 1
 		header, err := GetHeaderByNumber(ctx, self.odr, num)
 		if header != nil && err == nil {
 			self.mu.Lock()
diff --git a/light/nodeset.go b/light/nodeset.go
index ffdb71bb7..245b5eb76 100644
--- a/light/nodeset.go
+++ b/light/nodeset.go
@@ -29,7 +29,9 @@ import (
 // NodeSet stores a set of trie nodes. It implements trie.Database and can also
 // act as a cache for another trie.Database.
 type NodeSet struct {
-	db       map[string][]byte
+	nodes map[string][]byte
+	order []string
+
 	dataSize int
 	lock     sync.RWMutex
 }
@@ -37,7 +39,7 @@ type NodeSet struct {
 // NewNodeSet creates an empty node set
 func NewNodeSet() *NodeSet {
 	return &NodeSet{
-		db: make(map[string][]byte),
+		nodes: make(map[string][]byte),
 	}
 }
 
@@ -46,10 +48,15 @@ func (db *NodeSet) Put(key []byte, value []byte) error {
 	db.lock.Lock()
 	defer db.lock.Unlock()
 
-	if _, ok := db.db[string(key)]; !ok {
-		db.db[string(key)] = common.CopyBytes(value)
-		db.dataSize += len(value)
+	if _, ok := db.nodes[string(key)]; ok {
+		return nil
 	}
+	keystr := string(key)
+
+	db.nodes[keystr] = common.CopyBytes(value)
+	db.order = append(db.order, keystr)
+	db.dataSize += len(value)
+
 	return nil
 }
 
@@ -58,7 +65,7 @@ func (db *NodeSet) Get(key []byte) ([]byte, error) {
 	db.lock.RLock()
 	defer db.lock.RUnlock()
 
-	if entry, ok := db.db[string(key)]; ok {
+	if entry, ok := db.nodes[string(key)]; ok {
 		return entry, nil
 	}
 	return nil, errors.New("not found")
@@ -75,7 +82,7 @@ func (db *NodeSet) KeyCount() int {
 	db.lock.RLock()
 	defer db.lock.RUnlock()
 
-	return len(db.db)
+	return len(db.nodes)
 }
 
 // DataSize returns the aggregated data size of nodes in the set
@@ -92,8 +99,8 @@ func (db *NodeSet) NodeList() NodeList {
 	defer db.lock.RUnlock()
 
 	var values NodeList
-	for _, value := range db.db {
-		values = append(values, value)
+	for _, key := range db.order {
+		values = append(values, db.nodes[key])
 	}
 	return values
 }
@@ -103,7 +110,7 @@ func (db *NodeSet) Store(target ethdb.Putter) {
 	db.lock.RLock()
 	defer db.lock.RUnlock()
 
-	for key, value := range db.db {
+	for key, value := range db.nodes {
 		target.Put([]byte(key), value)
 	}
 }
diff --git a/light/odr_util.go b/light/odr_util.go
index 33a8e80ce..8f92d6442 100644
--- a/light/odr_util.go
+++ b/light/odr_util.go
@@ -52,13 +52,13 @@ func GetHeaderByNumber(ctx context.Context, odr OdrBackend, number uint64) (*typ
 		for chtCount > 0 && canonicalHash != sectionHead && canonicalHash != (common.Hash{}) {
 			chtCount--
 			if chtCount > 0 {
-				sectionHeadNum = chtCount*ChtFrequency - 1
+				sectionHeadNum = chtCount*CHTFrequencyClient - 1
 				sectionHead = odr.ChtIndexer().SectionHead(chtCount - 1)
 				canonicalHash = core.GetCanonicalHash(db, sectionHeadNum)
 			}
 		}
 	}
-	if number >= chtCount*ChtFrequency {
+	if number >= chtCount*CHTFrequencyClient {
 		return nil, ErrNoTrustedCht
 	}
 	r := &ChtRequest{ChtRoot: GetChtRoot(db, chtCount-1, sectionHead), ChtNum: chtCount - 1, BlockNum: number}
diff --git a/light/postprocess.go b/light/postprocess.go
index 160d07b17..b6756de51 100644
--- a/light/postprocess.go
+++ b/light/postprocess.go
@@ -19,7 +19,6 @@ package light
 import (
 	"encoding/binary"
 	"errors"
-	"fmt"
 	"math/big"
 	"time"
 
@@ -35,8 +34,14 @@ import (
 )
 
 const (
-	ChtFrequency                   = 32768
-	ChtV1Frequency                 = 4096 // as long as we want to retain LES/1 compatibility, servers generate CHTs with the old, higher frequency
+	// CHTFrequencyClient is the block frequency for creating CHTs on the client side.
+	CHTFrequencyClient = 32768
+
+	// CHTFrequencyServer is the block frequency for creating CHTs on the server side.
+	// Eventually this can be merged back with the client version, but that requires a
+	// full database upgrade, so that should be left for a suitable moment.
+	CHTFrequencyServer = 4096
+
 	HelperTrieConfirmations        = 2048 // number of confirmations before a server is expected to have the given HelperTrie available
 	HelperTrieProcessConfirmations = 256  // number of confirmations before a HelperTrie is generated
 )
@@ -100,7 +105,7 @@ func GetChtRoot(db ethdb.Database, sectionIdx uint64, sectionHead common.Hash) c
 // GetChtV2Root reads the CHT root assoctiated to the given section from the database
 // Note that sectionIdx is specified according to LES/2 CHT section size
 func GetChtV2Root(db ethdb.Database, sectionIdx uint64, sectionHead common.Hash) common.Hash {
-	return GetChtRoot(db, (sectionIdx+1)*(ChtFrequency/ChtV1Frequency)-1, sectionHead)
+	return GetChtRoot(db, (sectionIdx+1)*(CHTFrequencyClient/CHTFrequencyServer)-1, sectionHead)
 }
 
 // StoreChtRoot writes the CHT root assoctiated to the given section into the database
@@ -124,10 +129,10 @@ type ChtIndexerBackend struct {
 func NewChtIndexer(db ethdb.Database, clientMode bool) *core.ChainIndexer {
 	var sectionSize, confirmReq uint64
 	if clientMode {
-		sectionSize = ChtFrequency
+		sectionSize = CHTFrequencyClient
 		confirmReq = HelperTrieConfirmations
 	} else {
-		sectionSize = ChtV1Frequency
+		sectionSize = CHTFrequencyServer
 		confirmReq = HelperTrieProcessConfirmations
 	}
 	idb := ethdb.NewTable(db, "chtIndex-")
@@ -174,8 +179,8 @@ func (c *ChtIndexerBackend) Commit() error {
 	}
 	c.triedb.Commit(root, false)
 
-	if ((c.section+1)*c.sectionSize)%ChtFrequency == 0 {
-		log.Info("Storing CHT", "idx", c.section*c.sectionSize/ChtFrequency, "sectionHead", fmt.Sprintf("%064x", c.lastHash), "root", fmt.Sprintf("%064x", root))
+	if ((c.section+1)*c.sectionSize)%CHTFrequencyClient == 0 {
+		log.Info("Storing CHT", "section", c.section*c.sectionSize/CHTFrequencyClient, "head", c.lastHash, "root", root)
 	}
 	StoreChtRoot(c.diskdb, c.section, c.lastHash, root)
 	return nil
@@ -294,7 +299,7 @@ func (b *BloomTrieIndexerBackend) Commit() error {
 	b.triedb.Commit(root, false)
 
 	sectionHead := b.sectionHeads[b.bloomTrieRatio-1]
-	log.Info("Storing BloomTrie", "section", b.section, "sectionHead", fmt.Sprintf("%064x", sectionHead), "root", fmt.Sprintf("%064x", root), "compression ratio", float64(compSize)/float64(decompSize))
+	log.Info("Storing bloom trie", "section", b.section, "head", sectionHead, "root", root, "compression", float64(compSize)/float64(decompSize))
 	StoreBloomTrieRoot(b.diskdb, b.section, sectionHead, root)
 
 	return nil