les: implement bloom request handler

les/backend.go

@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/bloombits"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/eth/downloader"
@@ -61,6 +62,7 @@ type LightEthereum struct {
 	// DB interfaces
 	chainDb ethdb.Database // Block chain database
 
+	bloomRequests                     chan chan *bloombits.Retrieval // Channel receiving bloom data retrieval requests
 	bbIndexer, chtIndexer, bltIndexer *core.ChainIndexer
 
 	ApiBackend *LesApiBackend
@@ -215,6 +217,7 @@ func (s *LightEthereum) Protocols() []p2p.Protocol {
 // Start implements node.Service, starting all internal goroutines needed by the
 // Ethereum protocol implementation.
 func (s *LightEthereum) Start(srvr *p2p.Server) error {
+	s.startBloomHandlers()
 	log.Warn("Light client mode is an experimental feature")
 	s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.networkId)
 	// search the topic belonging to the oldest supported protocol because

les/bloombits.go

@@ -0,0 +1,87 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package les
+
+import (
+	"context"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common/bitutil"
+	"github.com/ethereum/go-ethereum/light"
+)
+
+const (
+	// bloomServiceThreads is the number of goroutines used globally by an Ethereum
+	// instance to service bloombits lookups for all running filters.
+	bloomServiceThreads = 16
+
+	// bloomFilterThreads is the number of goroutines used locally per filter to
+	// multiplex requests onto the global servicing goroutines.
+	bloomFilterThreads = 3
+
+	// bloomRetrievalBatch is the maximum number of bloom bit retrievals to service
+	// in a single batch.
+	bloomRetrievalBatch = 16
+
+	// bloomRetrievalWait is the maximum time to wait for enough bloom bit requests
+	// to accumulate request an entire batch (avoiding hysteresis).
+	bloomRetrievalWait = time.Microsecond * 100
+)
+
+// startBloomHandlers starts a batch of goroutines to accept bloom bit database
+// retrievals from possibly a range of filters and serving the data to satisfy.
+func (eth *LightEthereum) startBloomHandlers() {
+	for i := 0; i < bloomServiceThreads; i++ {
+		go func() {
+			for {
+				select {
+				case <-eth.shutdownChan:
+					return
+
+				case request := <-eth.bloomRequests:
+					task := <-request
+
+					task.Bitsets = make([][]byte, len(task.Sections))
+
+					compVectors, err := light.GetBloomBits(context.Background(), eth.odr, task.Bit, task.Sections)
+					if err == nil {
+						for i, _ := range task.Sections {
+							if blob, err := bitutil.DecompressBytes(compVectors[i], int(light.BloomTrieFrequency/8)); err == nil {
+								task.Bitsets[i] = blob
+							} else {
+								task.Error = err
+							}
+						}
+					} else {
+						task.Error = err
+					}
+					request <- task
+				}
+			}
+		}()
+	}
+}
+
+const (
+	// bloomConfirms is the number of confirmation blocks before a bloom section is
+	// considered probably final and its rotated bits are calculated.
+	bloomConfirms = 256
+
+	// bloomThrottling is the time to wait between processing two consecutive index
+	// sections. It's useful during chain upgrades to prevent disk overload.
+	bloomThrottling = 100 * time.Millisecond
+)