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[release/1.4.10] core, eth: enforce network split post DAO hard-fork

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(cherry picked from commit 7f00e8c033)
This commit is contained in:
Péter Szilágyi
2016-07-08 20:59:11 +03:00
parent a0cc73a27a
commit 8c20fe17bd
4 changed files with 141 additions and 7 deletions
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58
eth/handler.go
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@ -45,6 +45,10 @@ const (
estHeaderRlpSize = 500 // Approximate size of an RLP encoded block header
)
var (
daoChallengeTimeout = 15 * time.Second // Time allowance for a node to reply to the DAO handshake challenge
)
// errIncompatibleConfig is returned if the requested protocols and configs are
// not compatible (low protocol version restrictions and high requirements).
var errIncompatibleConfig = errors.New("incompatible configuration")
@ -62,9 +66,10 @@ type ProtocolManager struct {
fastSync uint32 // Flag whether fast sync is enabled (gets disabled if we already have blocks)
synced uint32 // Flag whether we're considered synchronised (enables transaction processing)
txpool txPool
blockchain *core.BlockChain
chaindb ethdb.Database
txpool txPool
blockchain *core.BlockChain
chaindb ethdb.Database
chainconfig *core.ChainConfig
downloader *downloader.Downloader
fetcher *fetcher.Fetcher
@ -99,6 +104,7 @@ func NewProtocolManager(config *core.ChainConfig, fastSync bool, networkId int,
txpool: txpool,
blockchain: blockchain,
chaindb: chaindb,
chainconfig: config,
peers: newPeerSet(),
newPeerCh: make(chan *peer),
noMorePeers: make(chan struct{}),
@ -278,6 +284,18 @@ func (pm *ProtocolManager) handle(p *peer) error {
// after this will be sent via broadcasts.
pm.syncTransactions(p)
// If we're DAO hard-fork aware, validate any remote peer with regard to the hard-fork
if daoBlock := pm.chainconfig.DAOForkBlock; daoBlock != nil {
// Request the peer's DAO fork header for extra-data validation
if err := p.RequestHeadersByNumber(daoBlock.Uint64(), 1, 0, false); err != nil {
return err
}
// Start a timer to disconnect if the peer doesn't reply in time
p.forkDrop = time.AfterFunc(daoChallengeTimeout, func() {
glog.V(logger.Warn).Infof("%v: timed out DAO fork-check, dropping", p)
pm.removePeer(p.id)
})
}
// main loop. handle incoming messages.
for {
if err := pm.handleMsg(p); err != nil {
@ -479,9 +497,43 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
if err := msg.Decode(&headers); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
// If no headers were received, but we're expending a DAO fork check, maybe it's that
if len(headers) == 0 && p.forkDrop != nil {
// Possibly an empty reply to the fork header checks, sanity check TDs
verifyDAO := true
// If we already have a DAO header, we can check the peer's TD against it. If
// the peer's ahead of this, it too must have a reply to the DAO check
if daoHeader := pm.blockchain.GetHeaderByNumber(pm.chainconfig.DAOForkBlock.Uint64()); daoHeader != nil {
if p.Td().Cmp(pm.blockchain.GetTd(daoHeader.Hash(), daoHeader.Number.Uint64())) >= 0 {
verifyDAO = false
}
}
// If we're seemingly on the same chain, disable the drop timer
if verifyDAO {
glog.V(logger.Info).Infof("%v: seems to be on the same side of the DAO fork", p)
p.forkDrop.Stop()
p.forkDrop = nil
return nil
}
}
// Filter out any explicitly requested headers, deliver the rest to the downloader
filter := len(headers) == 1
if filter {
// If it's a potential DAO fork check, validate against the rules
if p.forkDrop != nil && pm.chainconfig.DAOForkBlock.Cmp(headers[0].Number) == 0 {
// Disable the fork drop timer
p.forkDrop.Stop()
p.forkDrop = nil
// Validate the header and either drop the peer or continue
if err := core.ValidateHeaderExtraData(pm.chainconfig, headers[0]); err != nil {
glog.V(logger.Info).Infof("%v: verified to be on the other side of the DAO fork, dropping", p)
return err
}
glog.V(logger.Info).Infof("%v: verified to be on the same side of the DAO fork", p)
}
// Irrelevant of the fork checks, send the header to the fetcher just in case
headers = pm.fetcher.FilterHeaders(headers, time.Now())
}
if len(headers) > 0 || !filter {