path: root/miner/remote_agent.go

// Copyright 2015 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 miner

import (
    "errors"
    "math/big"
    "sync"
    "sync/atomic"
    "time"

    "github.com/ethereum/ethash"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
)

type hashrate struct {
    ping time.Time
    rate uint64
}

type RemoteAgent struct {
    mu sync.Mutex

    quit     chan struct{}
    workCh   chan *Work
    returnCh chan<- *Result

    currentWork *Work
    work        map[common.Hash]*Work

    hashrateMu sync.RWMutex
    hashrate   map[common.Hash]hashrate

    running int32 // running indicates whether the agent is active. Call atomically
}

func NewRemoteAgent() *RemoteAgent {
    return &RemoteAgent{
        work:     make(map[common.Hash]*Work),
        hashrate: make(map[common.Hash]hashrate),
    }
}

func (a *RemoteAgent) SubmitHashrate(id common.Hash, rate uint64) {
    a.hashrateMu.Lock()
    defer a.hashrateMu.Unlock()

    a.hashrate[id] = hashrate{time.Now(), rate}
}

func (a *RemoteAgent) Work() chan<- *Work {
    return a.workCh
}

func (a *RemoteAgent) SetReturnCh(returnCh chan<- *Result) {
    a.returnCh = returnCh
}

func (a *RemoteAgent) Start() {
    if !atomic.CompareAndSwapInt32(&a.running, 0, 1) {
        return
    }

    a.quit = make(chan struct{})
    a.workCh = make(chan *Work, 1)
    go a.maintainLoop()
}

func (a *RemoteAgent) Stop() {
    if !atomic.CompareAndSwapInt32(&a.running, 1, 0) {
        return
    }

    close(a.quit)
    close(a.workCh)
}

// GetHashRate returns the accumulated hashrate of all identifier combined
func (a *RemoteAgent) GetHashRate() (tot int64) {
    a.hashrateMu.RLock()
    defer a.hashrateMu.RUnlock()

    // this could overflow
    for _, hashrate := range a.hashrate {
        tot += int64(hashrate.rate)
    }
    return
}

func (a *RemoteAgent) GetWork() ([3]string, error) {
    a.mu.Lock()
    defer a.mu.Unlock()

    var res [3]string

    if a.currentWork != nil {
        block := a.currentWork.Block

        res[0] = block.HashNoNonce().Hex()
        seedHash, _ := ethash.GetSeedHash(block.NumberU64())
        res[1] = common.BytesToHash(seedHash).Hex()
        // Calculate the "target" to be returned to the external miner
        n := big.NewInt(1)
        n.Lsh(n, 255)
        n.Div(n, block.Difficulty())
        n.Lsh(n, 1)
        res[2] = common.BytesToHash(n.Bytes()).Hex()

        a.work[block.HashNoNonce()] = a.currentWork
        return res, nil
    }
    return res, errors.New("No work available yet, don't panic.")
}

// Returns true or false, but does not indicate if the PoW was correct
func (a *RemoteAgent) SubmitWork(nonce uint64, mixDigest, hash common.Hash) bool {
    a.mu.Lock()
    defer a.mu.Unlock()

    // Make sure the work submitted is present
    if a.work[hash] != nil {
        block := a.work[hash].Block.WithMiningResult(nonce, mixDigest)
        a.returnCh <- &Result{a.work[hash], block}

        delete(a.work, hash)

        return true
    } else {
        glog.V(logger.Info).Infof("Work was submitted for %x but no pending work found\n", hash)
    }

    return false
}

func (a *RemoteAgent) maintainLoop() {
    ticker := time.Tick(5 * time.Second)

out:
    for {
        select {
        case <-a.quit:
            break out
        case work := <-a.workCh:
            a.mu.Lock()
            a.currentWork = work
            a.mu.Unlock()
        case <-ticker:
            // cleanup
            a.mu.Lock()
            for hash, work := range a.work {
                if time.Since(work.createdAt) > 7*(12*time.Second) {
                    delete(a.work, hash)
                }
            }
            a.mu.Unlock()

            a.hashrateMu.Lock()
            for id, hashrate := range a.hashrate {
                if time.Since(hashrate.ping) > 10*time.Second {
                    delete(a.hashrate, id)
                }
            }
            a.hashrateMu.Unlock()
        }
    }
}