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authorDeterminant <[email protected]>2020-06-28 14:47:41 -0400
committerDeterminant <[email protected]>2020-06-28 14:47:41 -0400
commitd235e2c6a5788ec4a6cff15a16f56b38a3876a0d (patch)
tree5f2727f7a50ee5840f889c82776d3a30a88dd59b /consensus/ethash/sealer.go
parent13ebd8bd9468e9d769d598b0ca2afb72ba78cb97 (diff)
...
Diffstat (limited to 'consensus/ethash/sealer.go')
-rw-r--r--consensus/ethash/sealer.go371
1 files changed, 371 insertions, 0 deletions
diff --git a/consensus/ethash/sealer.go b/consensus/ethash/sealer.go
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+// 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 ethash
+
+import (
+ "bytes"
+ crand "crypto/rand"
+ "encoding/json"
+ "errors"
+ "math"
+ "math/big"
+ "math/rand"
+ "net/http"
+ "runtime"
+ "sync"
+ "time"
+
+ "github.com/ava-labs/coreth/consensus"
+ "github.com/ava-labs/coreth/core/types"
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/common/hexutil"
+ "github.com/ava-labs/go-ethereum/log"
+)
+
+const (
+ // staleThreshold is the maximum depth of the acceptable stale but valid ethash solution.
+ staleThreshold = 7
+)
+
+var (
+ errNoMiningWork = errors.New("no mining work available yet")
+ errInvalidSealResult = errors.New("invalid or stale proof-of-work solution")
+)
+
+// Seal implements consensus.Engine, attempting to find a nonce that satisfies
+// the block's difficulty requirements.
+func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error {
+ // If we're running a fake PoW, simply return a 0 nonce immediately
+ if ethash.config.PowMode == ModeFake || ethash.config.PowMode == ModeFullFake {
+ header := block.Header()
+ header.Nonce, header.MixDigest = types.BlockNonce{}, common.Hash{}
+ select {
+ case results <- block.WithSeal(header):
+ default:
+ log.Warn("Sealing result is not read by miner", "mode", "fake", "sealhash", ethash.SealHash(block.Header()))
+ }
+ return nil
+ }
+ // If we're running a shared PoW, delegate sealing to it
+ if ethash.shared != nil {
+ return ethash.shared.Seal(chain, block, results, stop)
+ }
+ // Create a runner and the multiple search threads it directs
+ abort := make(chan struct{})
+
+ ethash.lock.Lock()
+ threads := ethash.threads
+ if ethash.rand == nil {
+ seed, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
+ if err != nil {
+ ethash.lock.Unlock()
+ return err
+ }
+ ethash.rand = rand.New(rand.NewSource(seed.Int64()))
+ }
+ ethash.lock.Unlock()
+ if threads == 0 {
+ threads = runtime.NumCPU()
+ }
+ if threads < 0 {
+ threads = 0 // Allows disabling local mining without extra logic around local/remote
+ }
+ // Push new work to remote sealer
+ if ethash.workCh != nil {
+ ethash.workCh <- &sealTask{block: block, results: results}
+ }
+ var (
+ pend sync.WaitGroup
+ locals = make(chan *types.Block)
+ )
+ for i := 0; i < threads; i++ {
+ pend.Add(1)
+ go func(id int, nonce uint64) {
+ defer pend.Done()
+ ethash.mine(block, id, nonce, abort, locals)
+ }(i, uint64(ethash.rand.Int63()))
+ }
+ // Wait until sealing is terminated or a nonce is found
+ go func() {
+ var result *types.Block
+ select {
+ case <-stop:
+ // Outside abort, stop all miner threads
+ close(abort)
+ case result = <-locals:
+ // One of the threads found a block, abort all others
+ select {
+ case results <- result:
+ default:
+ log.Warn("Sealing result is not read by miner", "mode", "local", "sealhash", ethash.SealHash(block.Header()))
+ }
+ close(abort)
+ case <-ethash.update:
+ // Thread count was changed on user request, restart
+ close(abort)
+ if err := ethash.Seal(chain, block, results, stop); err != nil {
+ log.Error("Failed to restart sealing after update", "err", err)
+ }
+ }
+ // Wait for all miners to terminate and return the block
+ pend.Wait()
+ }()
+ return nil
+}
+
+// mine is the actual proof-of-work miner that searches for a nonce starting from
+// seed that results in correct final block difficulty.
+func (ethash *Ethash) mine(block *types.Block, id int, seed uint64, abort chan struct{}, found chan *types.Block) {
+ // Extract some data from the header
+ var (
+ header = block.Header()
+ hash = ethash.SealHash(header).Bytes()
+ target = new(big.Int).Div(two256, header.Difficulty)
+ number = header.Number.Uint64()
+ dataset = ethash.dataset(number, false)
+ )
+ // Start generating random nonces until we abort or find a good one
+ var (
+ attempts = int64(0)
+ nonce = seed
+ )
+ logger := log.New("miner", id)
+ logger.Trace("Started ethash search for new nonces", "seed", seed)
+search:
+ for {
+ select {
+ case <-abort:
+ // Mining terminated, update stats and abort
+ logger.Trace("Ethash nonce search aborted", "attempts", nonce-seed)
+ ethash.hashrate.Mark(attempts)
+ break search
+
+ default:
+ // We don't have to update hash rate on every nonce, so update after after 2^X nonces
+ attempts++
+ if (attempts % (1 << 15)) == 0 {
+ ethash.hashrate.Mark(attempts)
+ attempts = 0
+ }
+ // Compute the PoW value of this nonce
+ digest, result := hashimotoFull(dataset.dataset, hash, nonce)
+ if new(big.Int).SetBytes(result).Cmp(target) <= 0 {
+ // Correct nonce found, create a new header with it
+ header = types.CopyHeader(header)
+ header.Nonce = types.EncodeNonce(nonce)
+ header.MixDigest = common.BytesToHash(digest)
+
+ // Seal and return a block (if still needed)
+ select {
+ case found <- block.WithSeal(header):
+ logger.Trace("Ethash nonce found and reported", "attempts", nonce-seed, "nonce", nonce)
+ case <-abort:
+ logger.Trace("Ethash nonce found but discarded", "attempts", nonce-seed, "nonce", nonce)
+ }
+ break search
+ }
+ nonce++
+ }
+ }
+ // Datasets are unmapped in a finalizer. Ensure that the dataset stays live
+ // during sealing so it's not unmapped while being read.
+ runtime.KeepAlive(dataset)
+}
+
+// remote is a standalone goroutine to handle remote mining related stuff.
+func (ethash *Ethash) remote(notify []string, noverify bool) {
+ var (
+ works = make(map[common.Hash]*types.Block)
+ rates = make(map[common.Hash]hashrate)
+
+ results chan<- *types.Block
+ currentBlock *types.Block
+ currentWork [4]string
+
+ notifyTransport = &http.Transport{}
+ notifyClient = &http.Client{
+ Transport: notifyTransport,
+ Timeout: time.Second,
+ }
+ notifyReqs = make([]*http.Request, len(notify))
+ )
+ // notifyWork notifies all the specified mining endpoints of the availability of
+ // new work to be processed.
+ notifyWork := func() {
+ work := currentWork
+ blob, _ := json.Marshal(work)
+
+ for i, url := range notify {
+ // Terminate any previously pending request and create the new work
+ if notifyReqs[i] != nil {
+ notifyTransport.CancelRequest(notifyReqs[i])
+ }
+ notifyReqs[i], _ = http.NewRequest("POST", url, bytes.NewReader(blob))
+ notifyReqs[i].Header.Set("Content-Type", "application/json")
+
+ // Push the new work concurrently to all the remote nodes
+ go func(req *http.Request, url string) {
+ res, err := notifyClient.Do(req)
+ if err != nil {
+ log.Warn("Failed to notify remote miner", "err", err)
+ } else {
+ log.Trace("Notified remote miner", "miner", url, "hash", log.Lazy{Fn: func() common.Hash { return common.HexToHash(work[0]) }}, "target", work[2])
+ res.Body.Close()
+ }
+ }(notifyReqs[i], url)
+ }
+ }
+ // makeWork creates a work package for external miner.
+ //
+ // The work package consists of 3 strings:
+ // result[0], 32 bytes hex encoded current block header pow-hash
+ // result[1], 32 bytes hex encoded seed hash used for DAG
+ // result[2], 32 bytes hex encoded boundary condition ("target"), 2^256/difficulty
+ // result[3], hex encoded block number
+ makeWork := func(block *types.Block) {
+ hash := ethash.SealHash(block.Header())
+
+ currentWork[0] = hash.Hex()
+ currentWork[1] = common.BytesToHash(SeedHash(block.NumberU64())).Hex()
+ currentWork[2] = common.BytesToHash(new(big.Int).Div(two256, block.Difficulty()).Bytes()).Hex()
+ currentWork[3] = hexutil.EncodeBig(block.Number())
+
+ // Trace the seal work fetched by remote sealer.
+ currentBlock = block
+ works[hash] = block
+ }
+ // submitWork verifies the submitted pow solution, returning
+ // whether the solution was accepted or not (not can be both a bad pow as well as
+ // any other error, like no pending work or stale mining result).
+ submitWork := func(nonce types.BlockNonce, mixDigest common.Hash, sealhash common.Hash) bool {
+ if currentBlock == nil {
+ log.Error("Pending work without block", "sealhash", sealhash)
+ return false
+ }
+ // Make sure the work submitted is present
+ block := works[sealhash]
+ if block == nil {
+ log.Warn("Work submitted but none pending", "sealhash", sealhash, "curnumber", currentBlock.NumberU64())
+ return false
+ }
+ // Verify the correctness of submitted result.
+ header := block.Header()
+ header.Nonce = nonce
+ header.MixDigest = mixDigest
+
+ start := time.Now()
+ if !noverify {
+ if err := ethash.verifySeal(nil, header, true); err != nil {
+ log.Warn("Invalid proof-of-work submitted", "sealhash", sealhash, "elapsed", common.PrettyDuration(time.Since(start)), "err", err)
+ return false
+ }
+ }
+ // Make sure the result channel is assigned.
+ if results == nil {
+ log.Warn("Ethash result channel is empty, submitted mining result is rejected")
+ return false
+ }
+ log.Trace("Verified correct proof-of-work", "sealhash", sealhash, "elapsed", common.PrettyDuration(time.Since(start)))
+
+ // Solutions seems to be valid, return to the miner and notify acceptance.
+ solution := block.WithSeal(header)
+
+ // The submitted solution is within the scope of acceptance.
+ if solution.NumberU64()+staleThreshold > currentBlock.NumberU64() {
+ select {
+ case results <- solution:
+ log.Debug("Work submitted is acceptable", "number", solution.NumberU64(), "sealhash", sealhash, "hash", solution.Hash())
+ return true
+ default:
+ log.Warn("Sealing result is not read by miner", "mode", "remote", "sealhash", sealhash)
+ return false
+ }
+ }
+ // The submitted block is too old to accept, drop it.
+ log.Warn("Work submitted is too old", "number", solution.NumberU64(), "sealhash", sealhash, "hash", solution.Hash())
+ return false
+ }
+
+ ticker := time.NewTicker(5 * time.Second)
+ defer ticker.Stop()
+
+ for {
+ select {
+ case work := <-ethash.workCh:
+ // Update current work with new received block.
+ // Note same work can be past twice, happens when changing CPU threads.
+ results = work.results
+
+ makeWork(work.block)
+
+ // Notify and requested URLs of the new work availability
+ notifyWork()
+
+ case work := <-ethash.fetchWorkCh:
+ // Return current mining work to remote miner.
+ if currentBlock == nil {
+ work.errc <- errNoMiningWork
+ } else {
+ work.res <- currentWork
+ }
+
+ case result := <-ethash.submitWorkCh:
+ // Verify submitted PoW solution based on maintained mining blocks.
+ if submitWork(result.nonce, result.mixDigest, result.hash) {
+ result.errc <- nil
+ } else {
+ result.errc <- errInvalidSealResult
+ }
+
+ case result := <-ethash.submitRateCh:
+ // Trace remote sealer's hash rate by submitted value.
+ rates[result.id] = hashrate{rate: result.rate, ping: time.Now()}
+ close(result.done)
+
+ case req := <-ethash.fetchRateCh:
+ // Gather all hash rate submitted by remote sealer.
+ var total uint64
+ for _, rate := range rates {
+ // this could overflow
+ total += rate.rate
+ }
+ req <- total
+
+ case <-ticker.C:
+ // Clear stale submitted hash rate.
+ for id, rate := range rates {
+ if time.Since(rate.ping) > 10*time.Second {
+ delete(rates, id)
+ }
+ }
+ // Clear stale pending blocks
+ if currentBlock != nil {
+ for hash, block := range works {
+ if block.NumberU64()+staleThreshold <= currentBlock.NumberU64() {
+ delete(works, hash)
+ }
+ }
+ }
+
+ case errc := <-ethash.exitCh:
+ // Exit remote loop if ethash is closed and return relevant error.
+ errc <- nil
+ log.Trace("Ethash remote sealer is exiting")
+ return
+ }
+ }
+}