71 lines
2.4 KiB
Go
71 lines
2.4 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package downloader
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import (
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"time"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/eth/protocols/eth"
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)
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// fetchHeadersByHash is a blocking version of Peer.RequestHeadersByHash which
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// handles all the cancellation, interruption and timeout mechanisms of a data
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// retrieval to allow blocking API calls.
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func (d *Downloader) fetchHeadersByHash(p *peerConnection, hash common.Hash, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error) {
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// Create the response sink and send the network request
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start := time.Now()
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resCh := make(chan *eth.Response)
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req, err := p.peer.RequestHeadersByHash(hash, amount, skip, reverse, resCh)
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if err != nil {
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return nil, nil, err
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}
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defer req.Close()
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// Wait until the response arrives, the request is cancelled or times out
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ttl := d.peers.rates.TargetTimeout()
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timeoutTimer := time.NewTimer(ttl)
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defer timeoutTimer.Stop()
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select {
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case <-d.cancelCh:
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return nil, nil, errCanceled
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case <-timeoutTimer.C:
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// Header retrieval timed out, update the metrics
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p.log.Debug("Header request timed out", "elapsed", ttl)
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headerTimeoutMeter.Mark(1)
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return nil, nil, errTimeout
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case res := <-resCh:
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// Headers successfully retrieved, update the metrics
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headerReqTimer.Update(time.Since(start))
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headerInMeter.Mark(int64(len(*res.Res.(*eth.BlockHeadersRequest))))
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// Don't reject the packet even if it turns out to be bad, downloader will
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// disconnect the peer on its own terms. Simply delivery the headers to
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// be processed by the caller
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res.Done <- nil
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return *res.Res.(*eth.BlockHeadersRequest), res.Meta.([]common.Hash), nil
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}
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}
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