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peer.go
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peer.go
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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"bytes"
"container/list"
"fmt"
"io"
"net"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/conformal/btcchain"
"github.com/conformal/btcd/addrmgr"
"github.com/conformal/btcdb"
"github.com/conformal/btcutil"
"github.com/conformal/btcutil/bloom"
"github.com/conformal/btcwire"
socks "github.com/conformal/go-socks"
"github.com/davecgh/go-spew/spew"
)
const (
// maxProtocolVersion is the max protocol version the peer supports.
maxProtocolVersion = 70002
// outputBufferSize is the number of elements the output channels use.
outputBufferSize = 50
// invTrickleSize is the maximum amount of inventory to send in a single
// message when trickling inventory to remote peers.
maxInvTrickleSize = 1000
// maxKnownInventory is the maximum number of items to keep in the known
// inventory cache.
maxKnownInventory = 1000
// negotiateTimeoutSeconds is the number of seconds of inactivity before
// we timeout a peer that hasn't completed the initial version
// negotiation.
negotiateTimeoutSeconds = 30
// idleTimeoutMinutes is the number of minutes of inactivity before
// we time out a peer.
idleTimeoutMinutes = 5
// pingTimeoutMinutes is the number of minutes since we last sent a
// message requiring a reply before we will ping a host.
pingTimeoutMinutes = 2
)
var (
// userAgentName is the user agent name and is used to help identify
// ourselves to other bitcoin peers.
userAgentName = "btcd"
// userAgentVersion is the user agent version and is used to help
// identify ourselves to other bitcoin peers.
userAgentVersion = fmt.Sprintf("%d.%d.%d", appMajor, appMinor, appPatch)
)
// zeroHash is the zero value hash (all zeros). It is defined as a convenience.
var zeroHash btcwire.ShaHash
// minUint32 is a helper function to return the minimum of two uint32s.
// This avoids a math import and the need to cast to floats.
func minUint32(a, b uint32) uint32 {
if a < b {
return a
}
return b
}
// newNetAddress attempts to extract the IP address and port from the passed
// net.Addr interface and create a bitcoin NetAddress structure using that
// information.
func newNetAddress(addr net.Addr, services btcwire.ServiceFlag) (*btcwire.NetAddress, error) {
// addr will be a net.TCPAddr when not using a proxy.
if tcpAddr, ok := addr.(*net.TCPAddr); ok {
ip := tcpAddr.IP
port := uint16(tcpAddr.Port)
na := btcwire.NewNetAddressIPPort(ip, port, services)
return na, nil
}
// addr will be a socks.ProxiedAddr when using a proxy.
if proxiedAddr, ok := addr.(*socks.ProxiedAddr); ok {
ip := net.ParseIP(proxiedAddr.Host)
if ip == nil {
ip = net.ParseIP("0.0.0.0")
}
port := uint16(proxiedAddr.Port)
na := btcwire.NewNetAddressIPPort(ip, port, services)
return na, nil
}
// For the most part, addr should be one of the two above cases, but
// to be safe, fall back to trying to parse the information from the
// address string as a last resort.
host, portStr, err := net.SplitHostPort(addr.String())
if err != nil {
return nil, err
}
ip := net.ParseIP(host)
port, err := strconv.ParseUint(portStr, 10, 16)
if err != nil {
return nil, err
}
na := btcwire.NewNetAddressIPPort(ip, uint16(port), services)
return na, nil
}
// outMsg is used to house a message to be sent along with a channel to signal
// when the message has been sent (or won't be sent due to things such as
// shutdown)
type outMsg struct {
msg btcwire.Message
doneChan chan struct{}
}
// peer provides a bitcoin peer for handling bitcoin communications. The
// overall data flow is split into 3 goroutines and a separate block manager.
// Inbound messages are read via the inHandler goroutine and generally
// dispatched to their own handler. For inbound data-related messages such as
// blocks, transactions, and inventory, the data is passed on to the block
// manager to handle it. Outbound messages are queued via QueueMessage or
// QueueInventory. QueueMessage is intended for all messages, including
// responses to data such as blocks and transactions. QueueInventory, on the
// other hand, is only intended for relaying inventory as it employs a trickling
// mechanism to batch the inventory together. The data flow for outbound
// messages uses two goroutines, queueHandler and outHandler. The first,
// queueHandler, is used as a way for external entities (mainly block manager)
// to queue messages quickly regardless of whether the peer is currently
// sending or not. It acts as the traffic cop between the external world and
// the actual goroutine which writes to the network socket. In addition, the
// peer contains several functions which are of the form pushX, that are used
// to push messages to the peer. Internally they use QueueMessage.
type peer struct {
server *server
btcnet btcwire.BitcoinNet
started int32
connected int32
disconnect int32 // only to be used atomically
conn net.Conn
addr string
na *btcwire.NetAddress
inbound bool
persistent bool
knownAddresses map[string]struct{}
knownInventory *MruInventoryMap
knownInvMutex sync.Mutex
requestedTxns map[btcwire.ShaHash]struct{} // owned by blockmanager
requestedBlocks map[btcwire.ShaHash]struct{} // owned by blockmanager
retryCount int64
prevGetBlocksBegin *btcwire.ShaHash // owned by blockmanager
prevGetBlocksStop *btcwire.ShaHash // owned by blockmanager
prevGetHdrsBegin *btcwire.ShaHash // owned by blockmanager
prevGetHdrsStop *btcwire.ShaHash // owned by blockmanager
requestQueue *list.List
filter *bloom.Filter
relayMtx sync.Mutex
disableRelayTx bool
continueHash *btcwire.ShaHash
outputQueue chan outMsg
sendQueue chan outMsg
sendDoneQueue chan struct{}
queueWg sync.WaitGroup // TODO(oga) wg -> single use channel?
outputInvChan chan *btcwire.InvVect
txProcessed chan struct{}
blockProcessed chan struct{}
quit chan struct{}
StatsMtx sync.Mutex // protects all statistics below here.
versionKnown bool
protocolVersion uint32
services btcwire.ServiceFlag
timeConnected time.Time
lastSend time.Time
lastRecv time.Time
bytesReceived uint64
bytesSent uint64
userAgent string
lastBlock int32
lastPingNonce uint64 // Set to nonce if we have a pending ping.
lastPingTime time.Time // Time we sent last ping.
lastPingMicros int64 // Time for last ping to return.
}
// String returns the peer's address and directionality as a human-readable
// string.
func (p *peer) String() string {
return fmt.Sprintf("%s (%s)", p.addr, directionString(p.inbound))
}
// isKnownInventory returns whether or not the peer is known to have the passed
// inventory. It is safe for concurrent access.
func (p *peer) isKnownInventory(invVect *btcwire.InvVect) bool {
p.knownInvMutex.Lock()
defer p.knownInvMutex.Unlock()
if p.knownInventory.Exists(invVect) {
return true
}
return false
}
// AddKnownInventory adds the passed inventory to the cache of known inventory
// for the peer. It is safe for concurrent access.
func (p *peer) AddKnownInventory(invVect *btcwire.InvVect) {
p.knownInvMutex.Lock()
defer p.knownInvMutex.Unlock()
p.knownInventory.Add(invVect)
}
// VersionKnown returns the whether or not the version of a peer is known locally.
// It is safe for concurrent access.
func (p *peer) VersionKnown() bool {
p.StatsMtx.Lock()
defer p.StatsMtx.Unlock()
return p.versionKnown
}
// ProtocolVersion returns the peer protocol version in a manner that is safe
// for concurrent access.
func (p *peer) ProtocolVersion() uint32 {
p.StatsMtx.Lock()
defer p.StatsMtx.Unlock()
return p.protocolVersion
}
// RelayTxDisabled returns whether or not relaying of transactions is disabled.
// It is safe for concurrent access.
func (p *peer) RelayTxDisabled() bool {
p.relayMtx.Lock()
defer p.relayMtx.Unlock()
return p.disableRelayTx
}
// pushVersionMsg sends a version message to the connected peer using the
// current state.
func (p *peer) pushVersionMsg() error {
_, blockNum, err := p.server.db.NewestSha()
if err != nil {
return err
}
theirNa := p.na
// If we are behind a proxy and the connection comes from the proxy then
// we return an unroutable address as their address. This is to prevent
// leaking the tor proxy address.
if cfg.Proxy != "" {
proxyaddress, _, err := net.SplitHostPort(cfg.Proxy)
// invalid proxy means poorly configured, be on the safe side.
if err != nil || p.na.IP.String() == proxyaddress {
theirNa = &btcwire.NetAddress{
Timestamp: time.Now(),
IP: net.IP([]byte{0, 0, 0, 0}),
}
}
}
// Version message.
msg := btcwire.NewMsgVersion(
p.server.addrManager.GetBestLocalAddress(p.na), theirNa,
p.server.nonce, int32(blockNum))
msg.AddUserAgent(userAgentName, userAgentVersion)
// XXX: bitcoind appears to always enable the full node services flag
// of the remote peer netaddress field in the version message regardless
// of whether it knows it supports it or not. Also, bitcoind sets
// the services field of the local peer to 0 regardless of support.
//
// Realistically, this should be set as follows:
// - For outgoing connections:
// - Set the local netaddress services to what the local peer
// actually supports
// - Set the remote netaddress services to 0 to indicate no services
// as they are still unknown
// - For incoming connections:
// - Set the local netaddress services to what the local peer
// actually supports
// - Set the remote netaddress services to the what was advertised by
// by the remote peer in its version message
msg.AddrYou.Services = btcwire.SFNodeNetwork
// Advertise that we're a full node.
msg.Services = btcwire.SFNodeNetwork
// Advertise our max supported protocol version.
msg.ProtocolVersion = maxProtocolVersion
p.QueueMessage(msg, nil)
return nil
}
// updateAddresses potentially adds addresses to the address manager and
// requests known addresses from the remote peer depending on whether the peer
// is an inbound or outbound peer and other factors such as address routability
// and the negotiated protocol version.
func (p *peer) updateAddresses(msg *btcwire.MsgVersion) {
// Outbound connections.
if !p.inbound {
// TODO(davec): Only do this if not doing the initial block
// download and the local address is routable.
if !cfg.DisableListen /* && isCurrent? */ {
// Get address that best matches.
lna := p.server.addrManager.GetBestLocalAddress(p.na)
if addrmgr.IsRoutable(lna) {
addresses := []*btcwire.NetAddress{lna}
p.pushAddrMsg(addresses)
}
}
// Request known addresses if the server address manager needs
// more and the peer has a protocol version new enough to
// include a timestamp with addresses.
hasTimestamp := p.ProtocolVersion() >=
btcwire.NetAddressTimeVersion
if p.server.addrManager.NeedMoreAddresses() && hasTimestamp {
p.QueueMessage(btcwire.NewMsgGetAddr(), nil)
}
// Mark the address as a known good address.
p.server.addrManager.Good(p.na)
} else {
// A peer might not be advertising the same address that it
// actually connected from. One example of why this can happen
// is with NAT. Only add the address to the address manager if
// the addresses agree.
if addrmgr.NetAddressKey(&msg.AddrMe) == addrmgr.NetAddressKey(p.na) {
p.server.addrManager.AddAddress(p.na, p.na)
p.server.addrManager.Good(p.na)
}
}
}
// handleVersionMsg is invoked when a peer receives a version bitcoin message
// and is used to negotiate the protocol version details as well as kick start
// the communications.
func (p *peer) handleVersionMsg(msg *btcwire.MsgVersion) {
// Detect self connections.
if msg.Nonce == p.server.nonce {
peerLog.Debugf("Disconnecting peer connected to self %s", p)
p.Disconnect()
return
}
// Notify and disconnect clients that have a protocol version that is
// too old.
if msg.ProtocolVersion < int32(btcwire.MultipleAddressVersion) {
// Send a reject message indicating the protocol version is
// obsolete and wait for the message to be sent before
// disconnecting.
reason := fmt.Sprintf("protocol version must be %d or greater",
btcwire.MultipleAddressVersion)
p.PushRejectMsg(msg.Command(), btcwire.RejectObsolete, reason,
nil, true)
p.Disconnect()
return
}
// Updating a bunch of stats.
p.StatsMtx.Lock()
// Limit to one version message per peer.
if p.versionKnown {
p.logError("Only one version message per peer is allowed %s.",
p)
p.StatsMtx.Unlock()
// Send an reject message indicating the version message was
// incorrectly sent twice and wait for the message to be sent
// before disconnecting.
p.PushRejectMsg(msg.Command(), btcwire.RejectDuplicate,
"duplicate version message", nil, true)
p.Disconnect()
return
}
// Negotiate the protocol version.
p.protocolVersion = minUint32(p.protocolVersion, uint32(msg.ProtocolVersion))
p.versionKnown = true
peerLog.Debugf("Negotiated protocol version %d for peer %s",
p.protocolVersion, p)
p.lastBlock = msg.LastBlock
// Set the supported services for the peer to what the remote peer
// advertised.
p.services = msg.Services
// Set the remote peer's user agent.
p.userAgent = msg.UserAgent
p.StatsMtx.Unlock()
// Choose whether or not to relay transactions before a filter command
// is received.
p.relayMtx.Lock()
p.disableRelayTx = msg.DisableRelayTx
p.relayMtx.Unlock()
// Inbound connections.
if p.inbound {
// Set up a NetAddress for the peer to be used with AddrManager.
// We only do this inbound because outbound set this up
// at connection time and no point recomputing.
na, err := newNetAddress(p.conn.RemoteAddr(), p.services)
if err != nil {
p.logError("Can't get remote address: %v", err)
p.Disconnect()
return
}
p.na = na
// Send version.
err = p.pushVersionMsg()
if err != nil {
p.logError("Can't send version message to %s: %v",
p, err)
p.Disconnect()
return
}
}
// Send verack.
p.QueueMessage(btcwire.NewMsgVerAck(), nil)
// Update the address manager and request known addresses from the
// remote peer for outbound connections. This is skipped when running
// on the simulation test network since it is only intended to connect
// to specified peers and actively avoids advertising and connecting to
// discovered peers.
if !cfg.SimNet {
p.updateAddresses(msg)
}
// Signal the block manager this peer is a new sync candidate.
p.server.blockManager.NewPeer(p)
// TODO: Relay alerts.
}
// pushTxMsg sends a tx message for the provided transaction hash to the
// connected peer. An error is returned if the transaction hash is not known.
func (p *peer) pushTxMsg(sha *btcwire.ShaHash, doneChan, waitChan chan struct{}) error {
// Attempt to fetch the requested transaction from the pool. A
// call could be made to check for existence first, but simply trying
// to fetch a missing transaction results in the same behavior.
tx, err := p.server.txMemPool.FetchTransaction(sha)
if err != nil {
peerLog.Tracef("Unable to fetch tx %v from transaction "+
"pool: %v", sha, err)
if doneChan != nil {
doneChan <- struct{}{}
}
return err
}
// Once we have fetched data wait for any previous operation to finish.
if waitChan != nil {
<-waitChan
}
p.QueueMessage(tx.MsgTx(), doneChan)
return nil
}
// pushBlockMsg sends a block message for the provided block hash to the
// connected peer. An error is returned if the block hash is not known.
func (p *peer) pushBlockMsg(sha *btcwire.ShaHash, doneChan, waitChan chan struct{}) error {
blk, err := p.server.db.FetchBlockBySha(sha)
if err != nil {
peerLog.Tracef("Unable to fetch requested block sha %v: %v",
sha, err)
if doneChan != nil {
doneChan <- struct{}{}
}
return err
}
// Once we have fetched data wait for any previous operation to finish.
if waitChan != nil {
<-waitChan
}
// We only send the channel for this message if we aren't sending
// an inv straight after.
var dc chan struct{}
sendInv := p.continueHash != nil && p.continueHash.IsEqual(sha)
if !sendInv {
dc = doneChan
}
p.QueueMessage(blk.MsgBlock(), dc)
// When the peer requests the final block that was advertised in
// response to a getblocks message which requested more blocks than
// would fit into a single message, send it a new inventory message
// to trigger it to issue another getblocks message for the next
// batch of inventory.
if p.continueHash != nil && p.continueHash.IsEqual(sha) {
hash, _, err := p.server.db.NewestSha()
if err == nil {
invMsg := btcwire.NewMsgInvSizeHint(1)
iv := btcwire.NewInvVect(btcwire.InvTypeBlock, hash)
invMsg.AddInvVect(iv)
p.QueueMessage(invMsg, doneChan)
p.continueHash = nil
} else if doneChan != nil {
doneChan <- struct{}{}
}
}
return nil
}
// pushMerkleBlockMsg sends a merkleblock message for the provided block hash to
// the connected peer. Since a merkle block requires the peer to have a filter
// loaded, this call will simply be ignored if there is no filter loaded. An
// error is returned if the block hash is not known.
func (p *peer) pushMerkleBlockMsg(sha *btcwire.ShaHash, doneChan, waitChan chan struct{}) error {
// Do not send a response if the peer doesn't have a filter loaded.
if !p.filter.IsLoaded() {
if doneChan != nil {
doneChan <- struct{}{}
}
return nil
}
blk, err := p.server.db.FetchBlockBySha(sha)
if err != nil {
peerLog.Tracef("Unable to fetch requested block sha %v: %v",
sha, err)
if doneChan != nil {
doneChan <- struct{}{}
}
return err
}
// Generate a merkle block by filtering the requested block according
// to the filter for the peer and fetch any matched transactions from
// the database.
merkle, matchedHashes := bloom.NewMerkleBlock(blk, p.filter)
txList := p.server.db.FetchTxByShaList(matchedHashes)
// Warn on any missing transactions which should not happen since the
// matched transactions come from an existing block. Also, find the
// final valid transaction index for later.
finalValidTxIndex := -1
for i, txR := range txList {
if txR.Err != nil || txR.Tx == nil {
warnMsg := fmt.Sprintf("Failed to fetch transaction "+
"%v which was matched by merkle block %v",
txR.Sha, sha)
if txR.Err != nil {
warnMsg += ": " + err.Error()
}
peerLog.Warnf(warnMsg)
continue
}
finalValidTxIndex = i
}
// Once we have fetched data wait for any previous operation to finish.
if waitChan != nil {
<-waitChan
}
// Send the merkleblock. Only send the done channel with this message
// if no transactions will be sent afterwards.
var dc chan struct{}
if finalValidTxIndex == -1 {
dc = doneChan
}
p.QueueMessage(merkle, dc)
// Finally, send any matched transactions.
for i, txR := range txList {
// Only send the done channel on the final transaction.
var dc chan struct{}
if i == finalValidTxIndex {
dc = doneChan
}
if txR.Err == nil && txR.Tx != nil {
p.QueueMessage(txR.Tx, dc)
}
}
return nil
}
// PushGetBlocksMsg sends a getblocks message for the provided block locator
// and stop hash. It will ignore back-to-back duplicate requests.
func (p *peer) PushGetBlocksMsg(locator btcchain.BlockLocator, stopHash *btcwire.ShaHash) error {
// Extract the begin hash from the block locator, if one was specified,
// to use for filtering duplicate getblocks requests.
// request.
var beginHash *btcwire.ShaHash
if len(locator) > 0 {
beginHash = locator[0]
}
// Filter duplicate getblocks requests.
if p.prevGetBlocksStop != nil && p.prevGetBlocksBegin != nil &&
beginHash != nil && stopHash.IsEqual(p.prevGetBlocksStop) &&
beginHash.IsEqual(p.prevGetBlocksBegin) {
peerLog.Tracef("Filtering duplicate [getblocks] with begin "+
"hash %v, stop hash %v", beginHash, stopHash)
return nil
}
// Construct the getblocks request and queue it to be sent.
msg := btcwire.NewMsgGetBlocks(stopHash)
for _, hash := range locator {
err := msg.AddBlockLocatorHash(hash)
if err != nil {
return err
}
}
p.QueueMessage(msg, nil)
// Update the previous getblocks request information for filtering
// duplicates.
p.prevGetBlocksBegin = beginHash
p.prevGetBlocksStop = stopHash
return nil
}
// PushGetHeadersMsg sends a getblocks message for the provided block locator
// and stop hash. It will ignore back-to-back duplicate requests.
func (p *peer) PushGetHeadersMsg(locator btcchain.BlockLocator, stopHash *btcwire.ShaHash) error {
// Extract the begin hash from the block locator, if one was specified,
// to use for filtering duplicate getheaders requests.
var beginHash *btcwire.ShaHash
if len(locator) > 0 {
beginHash = locator[0]
}
// Filter duplicate getheaders requests.
if p.prevGetHdrsStop != nil && p.prevGetHdrsBegin != nil &&
beginHash != nil && stopHash.IsEqual(p.prevGetHdrsStop) &&
beginHash.IsEqual(p.prevGetHdrsBegin) {
peerLog.Tracef("Filtering duplicate [getheaders] with begin "+
"hash %v", beginHash)
return nil
}
// Construct the getheaders request and queue it to be sent.
msg := btcwire.NewMsgGetHeaders()
msg.HashStop = *stopHash
for _, hash := range locator {
err := msg.AddBlockLocatorHash(hash)
if err != nil {
return err
}
}
p.QueueMessage(msg, nil)
// Update the previous getheaders request information for filtering
// duplicates.
p.prevGetHdrsBegin = beginHash
p.prevGetHdrsStop = stopHash
return nil
}
// PushRejectMsg sends a reject message for the provided command, reject code,
// and reject reason, and hash. The hash will only be used when the command
// is a tx or block and should be nil in other cases. The wait parameter will
// cause the function to block until the reject message has actually been sent.
func (p *peer) PushRejectMsg(command string, code btcwire.RejectCode, reason string, hash *btcwire.ShaHash, wait bool) {
// Don't bother sending the reject message if the protocol version
// is too low.
if p.VersionKnown() && p.ProtocolVersion() < btcwire.RejectVersion {
return
}
msg := btcwire.NewMsgReject(command, code, reason)
if command == btcwire.CmdTx || command == btcwire.CmdBlock {
if hash == nil {
peerLog.Warnf("Sending a reject message for command "+
"type %v which should have specified a hash "+
"but does not", command)
hash = &zeroHash
}
msg.Hash = *hash
}
// Send the message without waiting if the caller has not requested it.
if !wait {
p.QueueMessage(msg, nil)
return
}
// Send the message and block until it has been sent before returning.
doneChan := make(chan struct{}, 1)
p.QueueMessage(msg, doneChan)
<-doneChan
}
// handleMemPoolMsg is invoked when a peer receives a mempool bitcoin message.
// It creates and sends an inventory message with the contents of the memory
// pool up to the maximum inventory allowed per message. When the peer has a
// bloom filter loaded, the contents are filtered accordingly.
func (p *peer) handleMemPoolMsg(msg *btcwire.MsgMemPool) {
// Generate inventory message with the available transactions in the
// transaction memory pool. Limit it to the max allowed inventory
// per message. The the NewMsgInvSizeHint function automatically limits
// the passed hint to the maximum allowed, so it's safe to pass it
// without double checking it here.
txDescs := p.server.txMemPool.TxDescs()
invMsg := btcwire.NewMsgInvSizeHint(uint(len(txDescs)))
for i, txDesc := range txDescs {
// Another thread might have removed the transaction from the
// pool since the initial query.
hash := txDesc.Tx.Sha()
if !p.server.txMemPool.IsTransactionInPool(hash) {
continue
}
// Either add all transactions when there is no bloom filter,
// or only the transactions that match the filter when there is
// one.
if !p.filter.IsLoaded() || p.filter.MatchTxAndUpdate(txDesc.Tx) {
iv := btcwire.NewInvVect(btcwire.InvTypeTx, hash)
invMsg.AddInvVect(iv)
if i+1 >= btcwire.MaxInvPerMsg {
break
}
}
}
// Send the inventory message if there is anything to send.
if len(invMsg.InvList) > 0 {
p.QueueMessage(invMsg, nil)
}
}
// handleTxMsg is invoked when a peer receives a tx bitcoin message. It blocks
// until the bitcoin transaction has been fully processed. Unlock the block
// handler this does not serialize all transactions through a single thread
// transactions don't rely on the previous one in a linear fashion like blocks.
func (p *peer) handleTxMsg(msg *btcwire.MsgTx) {
// Add the transaction to the known inventory for the peer.
// Convert the raw MsgTx to a btcutil.Tx which provides some convenience
// methods and things such as hash caching.
tx := btcutil.NewTx(msg)
iv := btcwire.NewInvVect(btcwire.InvTypeTx, tx.Sha())
p.AddKnownInventory(iv)
// Queue the transaction up to be handled by the block manager and
// intentionally block further receives until the transaction is fully
// processed and known good or bad. This helps prevent a malicious peer
// from queueing up a bunch of bad transactions before disconnecting (or
// being disconnected) and wasting memory.
p.server.blockManager.QueueTx(tx, p)
<-p.txProcessed
}
// handleBlockMsg is invoked when a peer receives a block bitcoin message. It
// blocks until the bitcoin block has been fully processed.
func (p *peer) handleBlockMsg(msg *btcwire.MsgBlock, buf []byte) {
// Convert the raw MsgBlock to a btcutil.Block which provides some
// convenience methods and things such as hash caching.
block := btcutil.NewBlockFromBlockAndBytes(msg, buf)
// Add the block to the known inventory for the peer.
hash, err := block.Sha()
if err != nil {
peerLog.Errorf("Unable to get block hash: %v", err)
return
}
iv := btcwire.NewInvVect(btcwire.InvTypeBlock, hash)
p.AddKnownInventory(iv)
// Queue the block up to be handled by the block
// manager and intentionally block further receives
// until the bitcoin block is fully processed and known
// good or bad. This helps prevent a malicious peer
// from queueing up a bunch of bad blocks before
// disconnecting (or being disconnected) and wasting
// memory. Additionally, this behavior is depended on
// by at least the block acceptance test tool as the
// reference implementation processes blocks in the same
// thread and therefore blocks further messages until
// the bitcoin block has been fully processed.
p.server.blockManager.QueueBlock(block, p)
<-p.blockProcessed
}
// handleInvMsg is invoked when a peer receives an inv bitcoin message and is
// used to examine the inventory being advertised by the remote peer and react
// accordingly. We pass the message down to blockmanager which will call
// QueueMessage with any appropriate responses.
func (p *peer) handleInvMsg(msg *btcwire.MsgInv) {
p.server.blockManager.QueueInv(msg, p)
}
// handleHeadersMsg is invoked when a peer receives a headers bitcoin message.
// The message is passed down to the block manager.
func (p *peer) handleHeadersMsg(msg *btcwire.MsgHeaders) {
p.server.blockManager.QueueHeaders(msg, p)
}
// handleGetData is invoked when a peer receives a getdata bitcoin message and
// is used to deliver block and transaction information.
func (p *peer) handleGetDataMsg(msg *btcwire.MsgGetData) {
numAdded := 0
notFound := btcwire.NewMsgNotFound()
// We wait on the this wait channel periodically to prevent queueing
// far more data than we can send in a reasonable time, wasting memory.
// The waiting occurs after the database fetch for the next one to
// provide a little pipelining.
var waitChan chan struct{}
doneChan := make(chan struct{}, 1)
for i, iv := range msg.InvList {
var c chan struct{}
// If this will be the last message we send.
if i == len(msg.InvList)-1 && len(notFound.InvList) == 0 {
c = doneChan
} else if (i+1)%3 == 0 {
// Buffered so as to not make the send goroutine block.
c = make(chan struct{}, 1)
}
var err error
switch iv.Type {
case btcwire.InvTypeTx:
err = p.pushTxMsg(&iv.Hash, c, waitChan)
case btcwire.InvTypeBlock:
err = p.pushBlockMsg(&iv.Hash, c, waitChan)
case btcwire.InvTypeFilteredBlock:
err = p.pushMerkleBlockMsg(&iv.Hash, c, waitChan)
default:
peerLog.Warnf("Unknown type in inventory request %d",
iv.Type)
continue
}
if err != nil {
notFound.AddInvVect(iv)
// When there is a failure fetching the final entry
// and the done channel was sent in due to there
// being no outstanding not found inventory, consume
// it here because there is now not found inventory
// that will use the channel momentarily.
if i == len(msg.InvList)-1 && c != nil {
<-c
}
}
numAdded++
waitChan = c
}
if len(notFound.InvList) != 0 {
p.QueueMessage(notFound, doneChan)
}
// Wait for messages to be sent. We can send quite a lot of data at this
// point and this will keep the peer busy for a decent amount of time.
// We don't process anything else by them in this time so that we
// have an idea of when we should hear back from them - else the idle
// timeout could fire when we were only half done sending the blocks.
if numAdded > 0 {
<-doneChan
}
}
// handleGetBlocksMsg is invoked when a peer receives a getblocks bitcoin message.
func (p *peer) handleGetBlocksMsg(msg *btcwire.MsgGetBlocks) {
// Return all block hashes to the latest one (up to max per message) if
// no stop hash was specified.
// Attempt to find the ending index of the stop hash if specified.
endIdx := btcdb.AllShas
if !msg.HashStop.IsEqual(&zeroHash) {
height, err := p.server.db.FetchBlockHeightBySha(&msg.HashStop)
if err == nil {
endIdx = height + 1
}
}
// Find the most recent known block based on the block locator.
// Use the block after the genesis block if no other blocks in the
// provided locator are known. This does mean the client will start
// over with the genesis block if unknown block locators are provided.
// This mirrors the behavior in the reference implementation.
startIdx := int64(1)
for _, hash := range msg.BlockLocatorHashes {
height, err := p.server.db.FetchBlockHeightBySha(hash)
if err == nil {
// Start with the next hash since we know this one.
startIdx = height + 1
break
}
}
// Don't attempt to fetch more than we can put into a single message.
autoContinue := false
if endIdx-startIdx > btcwire.MaxBlocksPerMsg {
endIdx = startIdx + btcwire.MaxBlocksPerMsg
autoContinue = true
}
// Generate inventory message.
//
// The FetchBlockBySha call is limited to a maximum number of hashes
// per invocation. Since the maximum number of inventory per message
// might be larger, call it multiple times with the appropriate indices
// as needed.
invMsg := btcwire.NewMsgInv()
for start := startIdx; start < endIdx; {
// Fetch the inventory from the block database.
hashList, err := p.server.db.FetchHeightRange(start, endIdx)
if err != nil {
peerLog.Warnf("Block lookup failed: %v", err)
return
}
// The database did not return any further hashes. Break out of
// the loop now.
if len(hashList) == 0 {
break
}
// Add block inventory to the message.
for _, hash := range hashList {
hashCopy := hash
iv := btcwire.NewInvVect(btcwire.InvTypeBlock, &hashCopy)
invMsg.AddInvVect(iv)
}
start += int64(len(hashList))
}
// Send the inventory message if there is anything to send.
if len(invMsg.InvList) > 0 {
invListLen := len(invMsg.InvList)
if autoContinue && invListLen == btcwire.MaxBlocksPerMsg {
// Intentionally use a copy of the final hash so there
// is not a reference into the inventory slice which
// would prevent the entire slice from being eligible
// for GC as soon as it's sent.
continueHash := invMsg.InvList[invListLen-1].Hash
p.continueHash = &continueHash
}
p.QueueMessage(invMsg, nil)
}
}
// handleGetHeadersMsg is invoked when a peer receives a getheaders bitcoin
// message.
func (p *peer) handleGetHeadersMsg(msg *btcwire.MsgGetHeaders) {
// Attempt to look up the height of the provided stop hash.
endIdx := btcdb.AllShas
height, err := p.server.db.FetchBlockHeightBySha(&msg.HashStop)
if err == nil {
endIdx = height + 1
}
// There are no block locators so a specific header is being requested
// as identified by the stop hash.
if len(msg.BlockLocatorHashes) == 0 {
// No blocks with the stop hash were found so there is nothing
// to do. Just return. This behavior mirrors the reference
// implementation.
if endIdx == btcdb.AllShas {
return
}
// Fetch and send the requested block header.
header, err := p.server.db.FetchBlockHeaderBySha(&msg.HashStop)
if err != nil {
peerLog.Warnf("Lookup of known block hash failed: %v",
err)
return
}
headersMsg := btcwire.NewMsgHeaders()
headersMsg.AddBlockHeader(header)
p.QueueMessage(headersMsg, nil)
return
}
// Find the most recent known block based on the block locator.
// Use the block after the genesis block if no other blocks in the
// provided locator are known. This does mean the client will start
// over with the genesis block if unknown block locators are provided.