plugeth/eth/handler_test.go
Felix Lange 37dd9086ec core: refactor genesis handling
This commit solves several issues concerning the genesis block:

* Genesis/ChainConfig loading was handled by cmd/geth code. This left
  library users in the cold. They could specify a JSON-encoded
  string and overwrite the config, but didn't get any of the additional
  checks performed by geth.
* Decoding and writing of genesis JSON was conflated in
  WriteGenesisBlock. This made it a lot harder to embed the genesis
  block into the forthcoming config file loader. This commit changes
  things so there is a single Genesis type that represents genesis
  blocks. All uses of Write*Genesis* are changed to use the new type
  instead.
* If the chain config supplied by the user was incompatible with the
  current chain (i.e. the chain had already advanced beyond a scheduled
  fork), it got overwritten. This is not an issue in practice because
  previous forks have always had the highest total difficulty. It might
  matter in the future though. The new code reverts the local chain to
  the point of the fork when upgrading configuration.

The change to genesis block data removes compression library
dependencies from package core.
2017-03-23 15:58:43 +01:00

525 lines
21 KiB
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 eth
import (
"math"
"math/big"
"math/rand"
"testing"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"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"
"github.com/ethereum/go-ethereum/pow"
)
var bigTxGas = new(big.Int).SetUint64(params.TxGas)
// Tests that protocol versions and modes of operations are matched up properly.
func TestProtocolCompatibility(t *testing.T) {
// Define the compatibility chart
tests := []struct {
version uint
fastSync bool
compatible bool
}{
{61, false, true}, {62, false, true}, {63, false, true},
{61, true, false}, {62, true, false}, {63, true, true},
}
// Make sure anything we screw up is restored
backup := ProtocolVersions
defer func() { ProtocolVersions = backup }()
// Try all available compatibility configs and check for errors
for i, tt := range tests {
ProtocolVersions = []uint{tt.version}
pm, err := newTestProtocolManager(tt.fastSync, 0, nil, nil)
if pm != nil {
defer pm.Stop()
}
if (err == nil && !tt.compatible) || (err != nil && tt.compatible) {
t.Errorf("test %d: compatibility mismatch: have error %v, want compatibility %v", i, err, tt.compatible)
}
}
}
// Tests that block headers can be retrieved from a remote chain based on user queries.
func TestGetBlockHeaders62(t *testing.T) { testGetBlockHeaders(t, 62) }
func TestGetBlockHeaders63(t *testing.T) { testGetBlockHeaders(t, 63) }
func testGetBlockHeaders(t *testing.T, protocol int) {
pm := newTestProtocolManagerMust(t, false, downloader.MaxHashFetch+15, nil, nil)
peer, _ := newTestPeer("peer", protocol, pm, true)
defer peer.close()
// Create a "random" unknown hash for testing
var unknown common.Hash
for i := range unknown {
unknown[i] = byte(i)
}
// Create a batch of tests for various scenarios
limit := uint64(downloader.MaxHeaderFetch)
tests := []struct {
query *getBlockHeadersData // The query to execute for header retrieval
expect []common.Hash // The hashes of the block whose headers are expected
}{
// A single random block should be retrievable by hash and number too
{
&getBlockHeadersData{Origin: hashOrNumber{Hash: pm.blockchain.GetBlockByNumber(limit / 2).Hash()}, Amount: 1},
[]common.Hash{pm.blockchain.GetBlockByNumber(limit / 2).Hash()},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: limit / 2}, Amount: 1},
[]common.Hash{pm.blockchain.GetBlockByNumber(limit / 2).Hash()},
},
// Multiple headers should be retrievable in both directions
{
&getBlockHeadersData{Origin: hashOrNumber{Number: limit / 2}, Amount: 3},
[]common.Hash{
pm.blockchain.GetBlockByNumber(limit / 2).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 + 1).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 + 2).Hash(),
},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: limit / 2}, Amount: 3, Reverse: true},
[]common.Hash{
pm.blockchain.GetBlockByNumber(limit / 2).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 - 1).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 - 2).Hash(),
},
},
// Multiple headers with skip lists should be retrievable
{
&getBlockHeadersData{Origin: hashOrNumber{Number: limit / 2}, Skip: 3, Amount: 3},
[]common.Hash{
pm.blockchain.GetBlockByNumber(limit / 2).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 + 4).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 + 8).Hash(),
},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: limit / 2}, Skip: 3, Amount: 3, Reverse: true},
[]common.Hash{
pm.blockchain.GetBlockByNumber(limit / 2).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 - 4).Hash(),
pm.blockchain.GetBlockByNumber(limit/2 - 8).Hash(),
},
},
// The chain endpoints should be retrievable
{
&getBlockHeadersData{Origin: hashOrNumber{Number: 0}, Amount: 1},
[]common.Hash{pm.blockchain.GetBlockByNumber(0).Hash()},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: pm.blockchain.CurrentBlock().NumberU64()}, Amount: 1},
[]common.Hash{pm.blockchain.CurrentBlock().Hash()},
},
// Ensure protocol limits are honored
{
&getBlockHeadersData{Origin: hashOrNumber{Number: pm.blockchain.CurrentBlock().NumberU64() - 1}, Amount: limit + 10, Reverse: true},
pm.blockchain.GetBlockHashesFromHash(pm.blockchain.CurrentBlock().Hash(), limit),
},
// Check that requesting more than available is handled gracefully
{
&getBlockHeadersData{Origin: hashOrNumber{Number: pm.blockchain.CurrentBlock().NumberU64() - 4}, Skip: 3, Amount: 3},
[]common.Hash{
pm.blockchain.GetBlockByNumber(pm.blockchain.CurrentBlock().NumberU64() - 4).Hash(),
pm.blockchain.GetBlockByNumber(pm.blockchain.CurrentBlock().NumberU64()).Hash(),
},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: 4}, Skip: 3, Amount: 3, Reverse: true},
[]common.Hash{
pm.blockchain.GetBlockByNumber(4).Hash(),
pm.blockchain.GetBlockByNumber(0).Hash(),
},
},
// Check that requesting more than available is handled gracefully, even if mid skip
{
&getBlockHeadersData{Origin: hashOrNumber{Number: pm.blockchain.CurrentBlock().NumberU64() - 4}, Skip: 2, Amount: 3},
[]common.Hash{
pm.blockchain.GetBlockByNumber(pm.blockchain.CurrentBlock().NumberU64() - 4).Hash(),
pm.blockchain.GetBlockByNumber(pm.blockchain.CurrentBlock().NumberU64() - 1).Hash(),
},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: 4}, Skip: 2, Amount: 3, Reverse: true},
[]common.Hash{
pm.blockchain.GetBlockByNumber(4).Hash(),
pm.blockchain.GetBlockByNumber(1).Hash(),
},
},
// Check a corner case where requesting more can iterate past the endpoints
{
&getBlockHeadersData{Origin: hashOrNumber{Number: 2}, Amount: 5, Reverse: true},
[]common.Hash{
pm.blockchain.GetBlockByNumber(2).Hash(),
pm.blockchain.GetBlockByNumber(1).Hash(),
pm.blockchain.GetBlockByNumber(0).Hash(),
},
},
// Check a corner case where skipping overflow loops back into the chain start
{
&getBlockHeadersData{Origin: hashOrNumber{Hash: pm.blockchain.GetBlockByNumber(3).Hash()}, Amount: 2, Reverse: false, Skip: math.MaxUint64 - 1},
[]common.Hash{
pm.blockchain.GetBlockByNumber(3).Hash(),
},
},
// Check a corner case where skipping overflow loops back to the same header
{
&getBlockHeadersData{Origin: hashOrNumber{Hash: pm.blockchain.GetBlockByNumber(1).Hash()}, Amount: 2, Reverse: false, Skip: math.MaxUint64},
[]common.Hash{
pm.blockchain.GetBlockByNumber(1).Hash(),
},
},
// Check that non existing headers aren't returned
{
&getBlockHeadersData{Origin: hashOrNumber{Hash: unknown}, Amount: 1},
[]common.Hash{},
}, {
&getBlockHeadersData{Origin: hashOrNumber{Number: pm.blockchain.CurrentBlock().NumberU64() + 1}, Amount: 1},
[]common.Hash{},
},
}
// Run each of the tests and verify the results against the chain
for i, tt := range tests {
// Collect the headers to expect in the response
headers := []*types.Header{}
for _, hash := range tt.expect {
headers = append(headers, pm.blockchain.GetBlockByHash(hash).Header())
}
// Send the hash request and verify the response
p2p.Send(peer.app, 0x03, tt.query)
if err := p2p.ExpectMsg(peer.app, 0x04, headers); err != nil {
t.Errorf("test %d: headers mismatch: %v", i, err)
}
// If the test used number origins, repeat with hashes as the too
if tt.query.Origin.Hash == (common.Hash{}) {
if origin := pm.blockchain.GetBlockByNumber(tt.query.Origin.Number); origin != nil {
tt.query.Origin.Hash, tt.query.Origin.Number = origin.Hash(), 0
p2p.Send(peer.app, 0x03, tt.query)
if err := p2p.ExpectMsg(peer.app, 0x04, headers); err != nil {
t.Errorf("test %d: headers mismatch: %v", i, err)
}
}
}
}
}
// Tests that block contents can be retrieved from a remote chain based on their hashes.
func TestGetBlockBodies62(t *testing.T) { testGetBlockBodies(t, 62) }
func TestGetBlockBodies63(t *testing.T) { testGetBlockBodies(t, 63) }
func testGetBlockBodies(t *testing.T, protocol int) {
pm := newTestProtocolManagerMust(t, false, downloader.MaxBlockFetch+15, nil, nil)
peer, _ := newTestPeer("peer", protocol, pm, true)
defer peer.close()
// Create a batch of tests for various scenarios
limit := downloader.MaxBlockFetch
tests := []struct {
random int // Number of blocks to fetch randomly from the chain
explicit []common.Hash // Explicitly requested blocks
available []bool // Availability of explicitly requested blocks
expected int // Total number of existing blocks to expect
}{
{1, nil, nil, 1}, // A single random block should be retrievable
{10, nil, nil, 10}, // Multiple random blocks should be retrievable
{limit, nil, nil, limit}, // The maximum possible blocks should be retrievable
{limit + 1, nil, nil, limit}, // No more than the possible block count should be returned
{0, []common.Hash{pm.blockchain.Genesis().Hash()}, []bool{true}, 1}, // The genesis block should be retrievable
{0, []common.Hash{pm.blockchain.CurrentBlock().Hash()}, []bool{true}, 1}, // The chains head block should be retrievable
{0, []common.Hash{{}}, []bool{false}, 0}, // A non existent block should not be returned
// Existing and non-existing blocks interleaved should not cause problems
{0, []common.Hash{
{},
pm.blockchain.GetBlockByNumber(1).Hash(),
{},
pm.blockchain.GetBlockByNumber(10).Hash(),
{},
pm.blockchain.GetBlockByNumber(100).Hash(),
{},
}, []bool{false, true, false, true, false, true, false}, 3},
}
// Run each of the tests and verify the results against the chain
for i, tt := range tests {
// Collect the hashes to request, and the response to expect
hashes, seen := []common.Hash{}, make(map[int64]bool)
bodies := []*blockBody{}
for j := 0; j < tt.random; j++ {
for {
num := rand.Int63n(int64(pm.blockchain.CurrentBlock().NumberU64()))
if !seen[num] {
seen[num] = true
block := pm.blockchain.GetBlockByNumber(uint64(num))
hashes = append(hashes, block.Hash())
if len(bodies) < tt.expected {
bodies = append(bodies, &blockBody{Transactions: block.Transactions(), Uncles: block.Uncles()})
}
break
}
}
}
for j, hash := range tt.explicit {
hashes = append(hashes, hash)
if tt.available[j] && len(bodies) < tt.expected {
block := pm.blockchain.GetBlockByHash(hash)
bodies = append(bodies, &blockBody{Transactions: block.Transactions(), Uncles: block.Uncles()})
}
}
// Send the hash request and verify the response
p2p.Send(peer.app, 0x05, hashes)
if err := p2p.ExpectMsg(peer.app, 0x06, bodies); err != nil {
t.Errorf("test %d: bodies mismatch: %v", i, err)
}
}
}
// Tests that the node state database can be retrieved based on hashes.
func TestGetNodeData63(t *testing.T) { testGetNodeData(t, 63) }
func testGetNodeData(t *testing.T, protocol int) {
// Define three accounts to simulate transactions with
acc1Key, _ := crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
acc2Key, _ := crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
acc1Addr := crypto.PubkeyToAddress(acc1Key.PublicKey)
acc2Addr := crypto.PubkeyToAddress(acc2Key.PublicKey)
signer := types.HomesteadSigner{}
// Create a chain generator with some simple transactions (blatantly stolen from @fjl/chain_markets_test)
generator := func(i int, block *core.BlockGen) {
switch i {
case 0:
// In block 1, the test bank sends account #1 some ether.
tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
block.AddTx(tx)
case 1:
// In block 2, the test bank sends some more ether to account #1.
// acc1Addr passes it on to account #2.
tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
block.AddTx(tx1)
block.AddTx(tx2)
case 2:
// Block 3 is empty but was mined by account #2.
block.SetCoinbase(acc2Addr)
block.SetExtra([]byte("yeehaw"))
case 3:
// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
b2 := block.PrevBlock(1).Header()
b2.Extra = []byte("foo")
block.AddUncle(b2)
b3 := block.PrevBlock(2).Header()
b3.Extra = []byte("foo")
block.AddUncle(b3)
}
}
// Assemble the test environment
pm := newTestProtocolManagerMust(t, false, 4, generator, nil)
peer, _ := newTestPeer("peer", protocol, pm, true)
defer peer.close()
// Fetch for now the entire chain db
hashes := []common.Hash{}
for _, key := range pm.chaindb.(*ethdb.MemDatabase).Keys() {
if len(key) == len(common.Hash{}) {
hashes = append(hashes, common.BytesToHash(key))
}
}
p2p.Send(peer.app, 0x0d, hashes)
msg, err := peer.app.ReadMsg()
if err != nil {
t.Fatalf("failed to read node data response: %v", err)
}
if msg.Code != 0x0e {
t.Fatalf("response packet code mismatch: have %x, want %x", msg.Code, 0x0c)
}
var data [][]byte
if err := msg.Decode(&data); err != nil {
t.Fatalf("failed to decode response node data: %v", err)
}
// Verify that all hashes correspond to the requested data, and reconstruct a state tree
for i, want := range hashes {
if hash := crypto.Keccak256Hash(data[i]); hash != want {
t.Errorf("data hash mismatch: have %x, want %x", hash, want)
}
}
statedb, _ := ethdb.NewMemDatabase()
for i := 0; i < len(data); i++ {
statedb.Put(hashes[i].Bytes(), data[i])
}
accounts := []common.Address{testBank, acc1Addr, acc2Addr}
for i := uint64(0); i <= pm.blockchain.CurrentBlock().NumberU64(); i++ {
trie, _ := state.New(pm.blockchain.GetBlockByNumber(i).Root(), statedb)
for j, acc := range accounts {
state, _ := pm.blockchain.State()
bw := state.GetBalance(acc)
bh := trie.GetBalance(acc)
if (bw != nil && bh == nil) || (bw == nil && bh != nil) {
t.Errorf("test %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
}
if bw != nil && bh != nil && bw.Cmp(bw) != 0 {
t.Errorf("test %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
}
}
}
}
// Tests that the transaction receipts can be retrieved based on hashes.
func TestGetReceipt63(t *testing.T) { testGetReceipt(t, 63) }
func testGetReceipt(t *testing.T, protocol int) {
// Define three accounts to simulate transactions with
acc1Key, _ := crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
acc2Key, _ := crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
acc1Addr := crypto.PubkeyToAddress(acc1Key.PublicKey)
acc2Addr := crypto.PubkeyToAddress(acc2Key.PublicKey)
signer := types.HomesteadSigner{}
// Create a chain generator with some simple transactions (blatantly stolen from @fjl/chain_markets_test)
generator := func(i int, block *core.BlockGen) {
switch i {
case 0:
// In block 1, the test bank sends account #1 some ether.
tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
block.AddTx(tx)
case 1:
// In block 2, the test bank sends some more ether to account #1.
// acc1Addr passes it on to account #2.
tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
block.AddTx(tx1)
block.AddTx(tx2)
case 2:
// Block 3 is empty but was mined by account #2.
block.SetCoinbase(acc2Addr)
block.SetExtra([]byte("yeehaw"))
case 3:
// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
b2 := block.PrevBlock(1).Header()
b2.Extra = []byte("foo")
block.AddUncle(b2)
b3 := block.PrevBlock(2).Header()
b3.Extra = []byte("foo")
block.AddUncle(b3)
}
}
// Assemble the test environment
pm := newTestProtocolManagerMust(t, false, 4, generator, nil)
peer, _ := newTestPeer("peer", protocol, pm, true)
defer peer.close()
// Collect the hashes to request, and the response to expect
hashes, receipts := []common.Hash{}, []types.Receipts{}
for i := uint64(0); i <= pm.blockchain.CurrentBlock().NumberU64(); i++ {
block := pm.blockchain.GetBlockByNumber(i)
hashes = append(hashes, block.Hash())
receipts = append(receipts, core.GetBlockReceipts(pm.chaindb, block.Hash(), block.NumberU64()))
}
// Send the hash request and verify the response
p2p.Send(peer.app, 0x0f, hashes)
if err := p2p.ExpectMsg(peer.app, 0x10, receipts); err != nil {
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(pow.FakePow)
db, _ = ethdb.NewMemDatabase()
config = &params.ChainConfig{DAOForkBlock: big.NewInt(1), DAOForkSupport: localForked}
gspec = &core.Genesis{Config: config}
genesis = gspec.MustCommit(db)
blockchain, _ = core.NewBlockChain(db, config, pow, evmux, vm.Config{})
)
pm, err := NewProtocolManager(config, false, NetworkId, 1000, 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 simulated
if !timeout {
blocks, _ := core.GenerateChain(&params.ChainConfig{}, 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)
}
time.Sleep(100 * time.Millisecond) // Sleep to avoid the verification racing with the drops
} 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)
}
}
}