core, eth: enforce network split post DAO hard-fork

pull/2814/head
Péter Szilágyi 8 years ago
parent a87089fd2d
commit 7f00e8c033
  1. 7
      core/block_validator.go
  2. 58
      eth/handler.go
  3. 73
      eth/handler_test.go
  4. 10
      eth/peer.go

@ -248,6 +248,13 @@ func ValidateHeader(config *ChainConfig, pow pow.PoW, header *types.Header, pare
return &BlockNonceErr{header.Number, header.Hash(), header.Nonce.Uint64()}
}
}
// If all checks passed, validate the extra-data field for hard forks
return ValidateHeaderExtraData(config, header)
}
// ValidateHeaderExtraData validates the extra-data field of a block header to
// ensure it conforms to hard-fork rules.
func ValidateHeaderExtraData(config *ChainConfig, header *types.Header) error {
// DAO hard-fork extension to the header validity: a) if the node is no-fork,
// do not accept blocks in the [fork, fork+10) range with the fork specific
// extra-data set; b) if the node is pro-fork, require blocks in the specific

@ -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 {
@ -481,9 +499,43 @@ 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 {

@ -20,6 +20,7 @@ import (
"math/big"
"math/rand"
"testing"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
@ -28,6 +29,7 @@ import (
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/params"
)
@ -580,3 +582,74 @@ func testGetReceipt(t *testing.T, protocol int) {
t.Errorf("receipts mismatch: %v", err)
}
}
// Tests that post eth protocol handshake, DAO fork-enabled clients also execute
// a DAO "challenge" verifying each others' DAO fork headers to ensure they're on
// compatible chains.
func TestDAOChallengeNoVsNo(t *testing.T) { testDAOChallenge(t, false, false, false) }
func TestDAOChallengeNoVsPro(t *testing.T) { testDAOChallenge(t, false, true, false) }
func TestDAOChallengeProVsNo(t *testing.T) { testDAOChallenge(t, true, false, false) }
func TestDAOChallengeProVsPro(t *testing.T) { testDAOChallenge(t, true, true, false) }
func TestDAOChallengeNoVsTimeout(t *testing.T) { testDAOChallenge(t, false, false, true) }
func TestDAOChallengeProVsTimeout(t *testing.T) { testDAOChallenge(t, true, true, true) }
func testDAOChallenge(t *testing.T, localForked, remoteForked bool, timeout bool) {
// Reduce the DAO handshake challenge timeout
if timeout {
defer func(old time.Duration) { daoChallengeTimeout = old }(daoChallengeTimeout)
daoChallengeTimeout = 500 * time.Millisecond
}
// Create a DAO aware protocol manager
var (
evmux = new(event.TypeMux)
pow = new(core.FakePow)
db, _ = ethdb.NewMemDatabase()
genesis = core.WriteGenesisBlockForTesting(db)
config = &core.ChainConfig{DAOForkBlock: big.NewInt(1), DAOForkSupport: localForked}
blockchain, _ = core.NewBlockChain(db, config, pow, evmux)
)
pm, err := NewProtocolManager(config, false, NetworkId, evmux, new(testTxPool), pow, blockchain, db)
if err != nil {
t.Fatalf("failed to start test protocol manager: %v", err)
}
pm.Start()
defer pm.Stop()
// Connect a new peer and check that we receive the DAO challenge
peer, _ := newTestPeer("peer", eth63, pm, true)
defer peer.close()
challenge := &getBlockHeadersData{
Origin: hashOrNumber{Number: config.DAOForkBlock.Uint64()},
Amount: 1,
Skip: 0,
Reverse: false,
}
if err := p2p.ExpectMsg(peer.app, GetBlockHeadersMsg, challenge); err != nil {
t.Fatalf("challenge mismatch: %v", err)
}
// Create a block to reply to the challenge if no timeout is simualted
if !timeout {
blocks, _ := core.GenerateChain(genesis, db, 1, func(i int, block *core.BlockGen) {
if remoteForked {
block.SetExtra(params.DAOForkBlockExtra)
}
})
if err := p2p.Send(peer.app, BlockHeadersMsg, []*types.Header{blocks[0].Header()}); err != nil {
t.Fatalf("failed to answer challenge: %v", err)
}
} else {
// Otherwise wait until the test timeout passes
time.Sleep(daoChallengeTimeout + 500*time.Millisecond)
}
// Verify that depending on fork side, the remote peer is maintained or dropped
if localForked == remoteForked && !timeout {
if peers := pm.peers.Len(); peers != 1 {
t.Fatalf("peer count mismatch: have %d, want %d", peers, 1)
}
} else {
if peers := pm.peers.Len(); peers != 0 {
t.Fatalf("peer count mismatch: have %d, want %d", peers, 0)
}
}
}

@ -59,10 +59,12 @@ type peer struct {
*p2p.Peer
rw p2p.MsgReadWriter
version int // Protocol version negotiated
head common.Hash
td *big.Int
lock sync.RWMutex
version int // Protocol version negotiated
forkDrop *time.Timer // Timed connection dropper if forks aren't validated in time
head common.Hash
td *big.Int
lock sync.RWMutex
knownTxs *set.Set // Set of transaction hashes known to be known by this peer
knownBlocks *set.Set // Set of block hashes known to be known by this peer

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