consensus/ethash: move remote agent logic to ethash internal (#15853)

* consensus/ethash: start remote ggoroutine to handle remote mining

* consensus/ethash: expose remote miner api

* consensus/ethash: expose submitHashrate api

* miner, ethash: push empty block to sealer without waiting execution

* consensus, internal: add getHashrate API for ethash

* consensus: add three method for consensus interface

* miner: expose consensus engine running status to miner

* eth, miner: specify etherbase when miner created

* miner: commit new work when consensus engine is started

* consensus, miner: fix some logics

* all: delete useless interfaces

* consensus: polish a bit

consensus/ethash/api.go

@@ -0,0 +1,117 @@
+// Copyright 2018 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 (
+	"errors"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+var errEthashStopped = errors.New("ethash stopped")
+
+// API exposes ethash related methods for the RPC interface.
+type API struct {
+	ethash *Ethash // Make sure the mode of ethash is normal.
+}
+
+// GetWork returns 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
+func (api *API) GetWork() ([3]string, error) {
+	if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+		return [3]string{}, errors.New("not supported")
+	}
+
+	var (
+		workCh = make(chan [3]string, 1)
+		errc   = make(chan error, 1)
+	)
+
+	select {
+	case api.ethash.fetchWorkCh <- &sealWork{errc: errc, res: workCh}:
+	case <-api.ethash.exitCh:
+		return [3]string{}, errEthashStopped
+	}
+
+	select {
+	case work := <-workCh:
+		return work, nil
+	case err := <-errc:
+		return [3]string{}, err
+	}
+}
+
+// SubmitWork can be used by external miner to submit their POW solution.
+// It returns an indication if the work was accepted.
+// Note either an invalid solution, a stale work a non-existent work will return false.
+func (api *API) SubmitWork(nonce types.BlockNonce, hash, digest common.Hash) bool {
+	if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+		return false
+	}
+
+	var errc = make(chan error, 1)
+
+	select {
+	case api.ethash.submitWorkCh <- &mineResult{
+		nonce:     nonce,
+		mixDigest: digest,
+		hash:      hash,
+		errc:      errc,
+	}:
+	case <-api.ethash.exitCh:
+		return false
+	}
+
+	err := <-errc
+	return err == nil
+}
+
+// SubmitHashrate can be used for remote miners to submit their hash rate.
+// This enables the node to report the combined hash rate of all miners
+// which submit work through this node.
+//
+// It accepts the miner hash rate and an identifier which must be unique
+// between nodes.
+func (api *API) SubmitHashRate(rate hexutil.Uint64, id common.Hash) bool {
+	if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+		return false
+	}
+
+	var done = make(chan struct{}, 1)
+
+	select {
+	case api.ethash.submitRateCh <- &hashrate{done: done, rate: uint64(rate), id: id}:
+	case <-api.ethash.exitCh:
+		return false
+	}
+
+	// Block until hash rate submitted successfully.
+	<-done
+
+	return true
+}
+
+// GetHashrate returns the current hashrate for local CPU miner and remote miner.
+func (api *API) GetHashrate() uint64 {
+	return uint64(api.ethash.Hashrate())
+}