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server.go
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server.go
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// Copyright (c) 2013-2017 The btcsuite developers
// Copyright (c) 2015-2017 The Decred developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"bytes"
"crypto/rand"
"encoding/binary"
"errors"
"fmt"
"math"
"net"
"runtime"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/btcsuite/btcd/addrmgr"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcd/blockchain/indexers"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/connmgr"
"github.com/btcsuite/btcd/database"
"github.com/btcsuite/btcd/mempool"
"github.com/btcsuite/btcd/mining"
"github.com/btcsuite/btcd/mining/cpuminer"
"github.com/btcsuite/btcd/peer"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcutil/bloom"
)
const (
// defaultServices describes the default services that are supported by
// the server.
defaultServices = wire.SFNodeNetwork | wire.SFNodeBloom
// defaultRequiredServices describes the default services that are
// required to be supported by outbound peers.
defaultRequiredServices = wire.SFNodeNetwork
// defaultTargetOutbound is the default number of outbound peers to target.
defaultTargetOutbound = 8
// connectionRetryInterval is the base amount of time to wait in between
// retries when connecting to persistent peers. It is adjusted by the
// number of retries such that there is a retry backoff.
connectionRetryInterval = time.Second * 5
)
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)
)
// onionAddr implements the net.Addr interface and represents a tor address.
type onionAddr struct {
addr string
}
// String returns the onion address.
//
// This is part of the net.Addr interface.
func (oa *onionAddr) String() string {
return oa.addr
}
// Network returns "onion".
//
// This is part of the net.Addr interface.
func (oa *onionAddr) Network() string {
return "onion"
}
// Ensure onionAddr implements the net.Addr interface.
var _ net.Addr = (*onionAddr)(nil)
// broadcastMsg provides the ability to house a bitcoin message to be broadcast
// to all connected peers except specified excluded peers.
type broadcastMsg struct {
message wire.Message
excludePeers []*serverPeer
}
// broadcastInventoryAdd is a type used to declare that the InvVect it contains
// needs to be added to the rebroadcast map
type broadcastInventoryAdd relayMsg
// broadcastInventoryDel is a type used to declare that the InvVect it contains
// needs to be removed from the rebroadcast map
type broadcastInventoryDel *wire.InvVect
// relayMsg packages an inventory vector along with the newly discovered
// inventory so the relay has access to that information.
type relayMsg struct {
invVect *wire.InvVect
data interface{}
}
// updatePeerHeightsMsg is a message sent from the blockmanager to the server
// after a new block has been accepted. The purpose of the message is to update
// the heights of peers that were known to announce the block before we
// connected it to the main chain or recognized it as an orphan. With these
// updates, peer heights will be kept up to date, allowing for fresh data when
// selecting sync peer candidacy.
type updatePeerHeightsMsg struct {
newHash *chainhash.Hash
newHeight int32
originPeer *serverPeer
}
// peerState maintains state of inbound, persistent, outbound peers as well
// as banned peers and outbound groups.
type peerState struct {
inboundPeers map[int32]*serverPeer
outboundPeers map[int32]*serverPeer
persistentPeers map[int32]*serverPeer
banned map[string]time.Time
outboundGroups map[string]int
}
// Count returns the count of all known peers.
func (ps *peerState) Count() int {
return len(ps.inboundPeers) + len(ps.outboundPeers) +
len(ps.persistentPeers)
}
// forAllOutboundPeers is a helper function that runs closure on all outbound
// peers known to peerState.
func (ps *peerState) forAllOutboundPeers(closure func(sp *serverPeer)) {
for _, e := range ps.outboundPeers {
closure(e)
}
for _, e := range ps.persistentPeers {
closure(e)
}
}
// forAllPeers is a helper function that runs closure on all peers known to
// peerState.
func (ps *peerState) forAllPeers(closure func(sp *serverPeer)) {
for _, e := range ps.inboundPeers {
closure(e)
}
ps.forAllOutboundPeers(closure)
}
// server provides a bitcoin server for handling communications to and from
// bitcoin peers.
type server struct {
// The following variables must only be used atomically.
// Putting the uint64s first makes them 64-bit aligned for 32-bit systems.
bytesReceived uint64 // Total bytes received from all peers since start.
bytesSent uint64 // Total bytes sent by all peers since start.
started int32
shutdown int32
shutdownSched int32
chainParams *chaincfg.Params
addrManager *addrmgr.AddrManager
connManager *connmgr.ConnManager
sigCache *txscript.SigCache
rpcServer *rpcServer
blockManager *blockManager
txMemPool *mempool.TxPool
cpuMiner *cpuminer.CPUMiner
modifyRebroadcastInv chan interface{}
newPeers chan *serverPeer
donePeers chan *serverPeer
banPeers chan *serverPeer
query chan interface{}
relayInv chan relayMsg
broadcast chan broadcastMsg
peerHeightsUpdate chan updatePeerHeightsMsg
wg sync.WaitGroup
quit chan struct{}
nat NAT
db database.DB
timeSource blockchain.MedianTimeSource
services wire.ServiceFlag
// The following fields are used for optional indexes. They will be nil
// if the associated index is not enabled. These fields are set during
// initial creation of the server and never changed afterwards, so they
// do not need to be protected for concurrent access.
txIndex *indexers.TxIndex
addrIndex *indexers.AddrIndex
}
// serverPeer extends the peer to maintain state shared by the server and
// the blockmanager.
type serverPeer struct {
// The following variables must only be used atomically
feeFilter int64
*peer.Peer
connReq *connmgr.ConnReq
server *server
persistent bool
continueHash *chainhash.Hash
relayMtx sync.Mutex
disableRelayTx bool
sentAddrs bool
requestQueue []*wire.InvVect
requestedTxns map[chainhash.Hash]struct{}
requestedBlocks map[chainhash.Hash]struct{}
filter *bloom.Filter
knownAddresses map[string]struct{}
banScore connmgr.DynamicBanScore
quit chan struct{}
// The following chans are used to sync blockmanager and server.
txProcessed chan struct{}
blockProcessed chan struct{}
}
// newServerPeer returns a new serverPeer instance. The peer needs to be set by
// the caller.
func newServerPeer(s *server, isPersistent bool) *serverPeer {
return &serverPeer{
server: s,
persistent: isPersistent,
requestedTxns: make(map[chainhash.Hash]struct{}),
requestedBlocks: make(map[chainhash.Hash]struct{}),
filter: bloom.LoadFilter(nil),
knownAddresses: make(map[string]struct{}),
quit: make(chan struct{}),
txProcessed: make(chan struct{}, 1),
blockProcessed: make(chan struct{}, 1),
}
}
// newestBlock returns the current best block hash and height using the format
// required by the configuration for the peer package.
func (sp *serverPeer) newestBlock() (*chainhash.Hash, int32, error) {
best := sp.server.blockManager.chain.BestSnapshot()
return &best.Hash, best.Height, nil
}
// addKnownAddresses adds the given addresses to the set of known addresses to
// the peer to prevent sending duplicate addresses.
func (sp *serverPeer) addKnownAddresses(addresses []*wire.NetAddress) {
for _, na := range addresses {
sp.knownAddresses[addrmgr.NetAddressKey(na)] = struct{}{}
}
}
// addressKnown true if the given address is already known to the peer.
func (sp *serverPeer) addressKnown(na *wire.NetAddress) bool {
_, exists := sp.knownAddresses[addrmgr.NetAddressKey(na)]
return exists
}
// setDisableRelayTx toggles relaying of transactions for the given peer.
// It is safe for concurrent access.
func (sp *serverPeer) setDisableRelayTx(disable bool) {
sp.relayMtx.Lock()
sp.disableRelayTx = disable
sp.relayMtx.Unlock()
}
// relayTxDisabled returns whether or not relaying of transactions for the given
// peer is disabled.
// It is safe for concurrent access.
func (sp *serverPeer) relayTxDisabled() bool {
sp.relayMtx.Lock()
isDisabled := sp.disableRelayTx
sp.relayMtx.Unlock()
return isDisabled
}
// pushAddrMsg sends an addr message to the connected peer using the provided
// addresses.
func (sp *serverPeer) pushAddrMsg(addresses []*wire.NetAddress) {
// Filter addresses already known to the peer.
addrs := make([]*wire.NetAddress, 0, len(addresses))
for _, addr := range addresses {
if !sp.addressKnown(addr) {
addrs = append(addrs, addr)
}
}
known, err := sp.PushAddrMsg(addrs)
if err != nil {
peerLog.Errorf("Can't push address message to %s: %v", sp.Peer, err)
sp.Disconnect()
return
}
sp.addKnownAddresses(known)
}
// addBanScore increases the persistent and decaying ban score fields by the
// values passed as parameters. If the resulting score exceeds half of the ban
// threshold, a warning is logged including the reason provided. Further, if
// the score is above the ban threshold, the peer will be banned and
// disconnected.
func (sp *serverPeer) addBanScore(persistent, transient uint32, reason string) {
// No warning is logged and no score is calculated if banning is disabled.
if cfg.DisableBanning {
return
}
warnThreshold := cfg.BanThreshold >> 1
if transient == 0 && persistent == 0 {
// The score is not being increased, but a warning message is still
// logged if the score is above the warn threshold.
score := sp.banScore.Int()
if score > warnThreshold {
peerLog.Warnf("Misbehaving peer %s: %s -- ban score is %d, "+
"it was not increased this time", sp, reason, score)
}
return
}
score := sp.banScore.Increase(persistent, transient)
if score > warnThreshold {
peerLog.Warnf("Misbehaving peer %s: %s -- ban score increased to %d",
sp, reason, score)
if score > cfg.BanThreshold {
peerLog.Warnf("Misbehaving peer %s -- banning and disconnecting",
sp)
sp.server.BanPeer(sp)
sp.Disconnect()
}
}
}
// OnVersion 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 (sp *serverPeer) OnVersion(_ *peer.Peer, msg *wire.MsgVersion) {
// Add the remote peer time as a sample for creating an offset against
// the local clock to keep the network time in sync.
sp.server.timeSource.AddTimeSample(sp.Addr(), msg.Timestamp)
// Signal the block manager this peer is a new sync candidate.
sp.server.blockManager.NewPeer(sp)
// Choose whether or not to relay transactions before a filter command
// is received.
sp.setDisableRelayTx(msg.DisableRelayTx)
// 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 {
addrManager := sp.server.addrManager
// Outbound connections.
if !sp.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 := addrManager.GetBestLocalAddress(sp.NA())
if addrmgr.IsRoutable(lna) {
// Filter addresses the peer already knows about.
addresses := []*wire.NetAddress{lna}
sp.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 := sp.ProtocolVersion() >=
wire.NetAddressTimeVersion
if addrManager.NeedMoreAddresses() && hasTimestamp {
sp.QueueMessage(wire.NewMsgGetAddr(), nil)
}
// Mark the address as a known good address.
addrManager.Good(sp.NA())
}
}
// Add valid peer to the server.
sp.server.AddPeer(sp)
}
// OnMemPool 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 (sp *serverPeer) OnMemPool(_ *peer.Peer, msg *wire.MsgMemPool) {
// Only allow mempool requests if the server has bloom filtering
// enabled.
if sp.server.services&wire.SFNodeBloom != wire.SFNodeBloom {
peerLog.Debugf("peer %v sent mempool request with bloom "+
"filtering disabled -- disconnecting", sp)
sp.Disconnect()
return
}
// A decaying ban score increase is applied to prevent flooding.
// The ban score accumulates and passes the ban threshold if a burst of
// mempool messages comes from a peer. The score decays each minute to
// half of its value.
sp.addBanScore(0, 33, "mempool")
// Generate inventory message with the available transactions in the
// transaction memory pool. Limit it to the max allowed inventory
// per message. The NewMsgInvSizeHint function automatically limits
// the passed hint to the maximum allowed, so it's safe to pass it
// without double checking it here.
txMemPool := sp.server.txMemPool
txDescs := txMemPool.TxDescs()
invMsg := wire.NewMsgInvSizeHint(uint(len(txDescs)))
for _, txDesc := range txDescs {
// Either add all transactions when there is no bloom filter,
// or only the transactions that match the filter when there is
// one.
if !sp.filter.IsLoaded() || sp.filter.MatchTxAndUpdate(txDesc.Tx) {
iv := wire.NewInvVect(wire.InvTypeTx, txDesc.Tx.Hash())
invMsg.AddInvVect(iv)
if len(invMsg.InvList)+1 > wire.MaxInvPerMsg {
break
}
}
}
// Send the inventory message if there is anything to send.
if len(invMsg.InvList) > 0 {
sp.QueueMessage(invMsg, nil)
}
}
// OnTx 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 (sp *serverPeer) OnTx(_ *peer.Peer, msg *wire.MsgTx) {
if cfg.BlocksOnly {
peerLog.Tracef("Ignoring tx %v from %v - blocksonly enabled",
msg.TxHash(), sp)
return
}
// 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 := wire.NewInvVect(wire.InvTypeTx, tx.Hash())
sp.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 queuing up a bunch of bad transactions before disconnecting (or
// being disconnected) and wasting memory.
sp.server.blockManager.QueueTx(tx, sp)
<-sp.txProcessed
}
// OnBlock is invoked when a peer receives a block bitcoin message. It
// blocks until the bitcoin block has been fully processed.
func (sp *serverPeer) OnBlock(_ *peer.Peer, msg *wire.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.
iv := wire.NewInvVect(wire.InvTypeBlock, block.Hash())
sp.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 queuing 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.
sp.server.blockManager.QueueBlock(block, sp)
<-sp.blockProcessed
}
// OnInv 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 (sp *serverPeer) OnInv(_ *peer.Peer, msg *wire.MsgInv) {
if !cfg.BlocksOnly {
if len(msg.InvList) > 0 {
sp.server.blockManager.QueueInv(msg, sp)
}
return
}
newInv := wire.NewMsgInvSizeHint(uint(len(msg.InvList)))
for _, invVect := range msg.InvList {
if invVect.Type == wire.InvTypeTx {
peerLog.Tracef("Ignoring tx %v in inv from %v -- "+
"blocksonly enabled", invVect.Hash, sp)
if sp.ProtocolVersion() >= wire.BIP0037Version {
peerLog.Infof("Peer %v is announcing "+
"transactions -- disconnecting", sp)
sp.Disconnect()
return
}
continue
}
err := newInv.AddInvVect(invVect)
if err != nil {
peerLog.Errorf("Failed to add inventory vector: %v", err)
break
}
}
if len(newInv.InvList) > 0 {
sp.server.blockManager.QueueInv(newInv, sp)
}
}
// OnHeaders is invoked when a peer receives a headers bitcoin
// message. The message is passed down to the block manager.
func (sp *serverPeer) OnHeaders(_ *peer.Peer, msg *wire.MsgHeaders) {
sp.server.blockManager.QueueHeaders(msg, sp)
}
// handleGetData is invoked when a peer receives a getdata bitcoin message and
// is used to deliver block and transaction information.
func (sp *serverPeer) OnGetData(_ *peer.Peer, msg *wire.MsgGetData) {
numAdded := 0
notFound := wire.NewMsgNotFound()
length := len(msg.InvList)
// A decaying ban score increase is applied to prevent exhausting resources
// with unusually large inventory queries.
// Requesting more than the maximum inventory vector length within a short
// period of time yields a score above the default ban threshold. Sustained
// bursts of small requests are not penalized as that would potentially ban
// peers performing IBD.
// This incremental score decays each minute to half of its value.
sp.addBanScore(0, uint32(length)*99/wire.MaxInvPerMsg, "getdata")
// We wait on this wait channel periodically to prevent queuing
// 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 == length-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 wire.InvTypeTx:
err = sp.server.pushTxMsg(sp, &iv.Hash, c, waitChan)
case wire.InvTypeBlock:
err = sp.server.pushBlockMsg(sp, &iv.Hash, c, waitChan)
case wire.InvTypeFilteredBlock:
err = sp.server.pushMerkleBlockMsg(sp, &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 {
sp.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
}
}
// OnGetBlocks is invoked when a peer receives a getblocks bitcoin
// message.
func (sp *serverPeer) OnGetBlocks(_ *peer.Peer, msg *wire.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.
chain := sp.server.blockManager.chain
endIdx := int32(math.MaxInt32)
if !msg.HashStop.IsEqual(&zeroHash) {
height, err := chain.BlockHeightByHash(&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 := int32(1)
for _, hash := range msg.BlockLocatorHashes {
height, err := chain.BlockHeightByHash(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 > wire.MaxBlocksPerMsg {
endIdx = startIdx + wire.MaxBlocksPerMsg
autoContinue = true
}
// Fetch the inventory from the block database.
hashList, err := chain.HeightRange(startIdx, endIdx)
if err != nil {
peerLog.Warnf("Block lookup failed: %v", err)
return
}
// Generate inventory message.
invMsg := wire.NewMsgInv()
for i := range hashList {
iv := wire.NewInvVect(wire.InvTypeBlock, &hashList[i])
invMsg.AddInvVect(iv)
}
// Send the inventory message if there is anything to send.
if len(invMsg.InvList) > 0 {
invListLen := len(invMsg.InvList)
if autoContinue && invListLen == wire.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
sp.continueHash = &continueHash
}
sp.QueueMessage(invMsg, nil)
}
}
// locateBlocks returns the hashes of the blocks after the first known block in
// locators, until hashStop is reached, or up to a max of
// wire.MaxBlockHeadersPerMsg block hashes. This implements the search
// algorithm used by getheaders.
func (s *server) locateBlocks(locators []*chainhash.Hash, hashStop *chainhash.Hash) ([]chainhash.Hash, error) {
// Attempt to look up the height of the provided stop hash.
chain := s.blockManager.chain
endIdx := int32(math.MaxInt32)
height, err := chain.BlockHeightByHash(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(locators) == 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 == math.MaxInt32 {
return nil, nil
}
return []chainhash.Hash{*hashStop}, nil
}
// 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 := int32(1)
for _, loc := range locators {
height, err := chain.BlockHeightByHash(loc)
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 wire
// message.
if endIdx-startIdx > wire.MaxBlockHeadersPerMsg {
endIdx = startIdx + wire.MaxBlockHeadersPerMsg
}
// Fetch the inventory from the block database.
return chain.HeightRange(startIdx, endIdx)
}
// fetchHeaders fetches and decodes headers from the db for each hash in
// blockHashes.
func fetchHeaders(chain *blockchain.BlockChain, blockHashes []chainhash.Hash) ([]wire.BlockHeader, error) {
headers := make([]wire.BlockHeader, 0, len(blockHashes))
for i := range blockHashes {
header, err := chain.FetchHeader(&blockHashes[i])
if err != nil {
return nil, err
}
headers = append(headers, header)
}
return headers, nil
}
// OnGetHeaders is invoked when a peer receives a getheaders bitcoin
// message.
func (sp *serverPeer) OnGetHeaders(_ *peer.Peer, msg *wire.MsgGetHeaders) {
// Ignore getheaders requests if not in sync.
if !sp.server.blockManager.IsCurrent() {
return
}
blockHashes, err := sp.server.locateBlocks(msg.BlockLocatorHashes,
&msg.HashStop)
if err != nil {
peerLog.Errorf("OnGetHeaders: failed to fetch hashes: %v", err)
return
}
headers, err := fetchHeaders(sp.server.blockManager.chain, blockHashes)
if err != nil {
peerLog.Errorf("OnGetHeaders: failed to fetch block headers: "+
"%v", err)
return
}
blockHeaders := make([]*wire.BlockHeader, len(headers))
for i := range headers {
blockHeaders[i] = &headers[i]
}
if len(blockHeaders) > wire.MaxBlockHeadersPerMsg {
peerLog.Warnf("OnGetHeaders: fetched more block headers than " +
"allowed per message")
// Can still recover from this error, just slice off the extra
// headers and continue queing the message.
blockHeaders = blockHeaders[:wire.MaxBlockHeaderPayload]
}
sp.QueueMessage(&wire.MsgHeaders{Headers: blockHeaders}, nil)
}
// enforceNodeBloomFlag disconnects the peer if the server is not configured to
// allow bloom filters. Additionally, if the peer has negotiated to a protocol
// version that is high enough to observe the bloom filter service support bit,
// it will be banned since it is intentionally violating the protocol.
func (sp *serverPeer) enforceNodeBloomFlag(cmd string) bool {
if sp.server.services&wire.SFNodeBloom != wire.SFNodeBloom {
// Ban the peer if the protocol version is high enough that the
// peer is knowingly violating the protocol and banning is
// enabled.
//
// NOTE: Even though the addBanScore function already examines
// whether or not banning is enabled, it is checked here as well
// to ensure the violation is logged and the peer is
// disconnected regardless.
if sp.ProtocolVersion() >= wire.BIP0111Version &&
!cfg.DisableBanning {
// Disonnect the peer regardless of whether it was
// banned.
sp.addBanScore(100, 0, cmd)
sp.Disconnect()
return false
}
// Disconnect the peer regardless of protocol version or banning
// state.
peerLog.Debugf("%s sent an unsupported %s request -- "+
"disconnecting", sp, cmd)
sp.Disconnect()
return false
}
return true
}
// OnFeeFilter is invoked when a peer receives a feefilter bitcoin message and
// is used by remote peers to request that no transactions which have a fee rate
// lower than provided value are inventoried to them. The peer will be
// disconnected if an invalid fee filter value is provided.
func (sp *serverPeer) OnFeeFilter(_ *peer.Peer, msg *wire.MsgFeeFilter) {
// Check that the passed minimum fee is a valid amount.
if msg.MinFee < 0 || msg.MinFee > btcutil.MaxSatoshi {
peerLog.Debugf("Peer %v sent an invalid feefilter '%v' -- "+
"disconnecting", sp, btcutil.Amount(msg.MinFee))
sp.Disconnect()
return
}
atomic.StoreInt64(&sp.feeFilter, msg.MinFee)
}
// OnFilterAdd is invoked when a peer receives a filteradd bitcoin
// message and is used by remote peers to add data to an already loaded bloom
// filter. The peer will be disconnected if a filter is not loaded when this
// message is received or the server is not configured to allow bloom filters.
func (sp *serverPeer) OnFilterAdd(_ *peer.Peer, msg *wire.MsgFilterAdd) {
// Disconnect and/or ban depending on the node bloom services flag and
// negotiated protocol version.
if !sp.enforceNodeBloomFlag(msg.Command()) {
return
}
if sp.filter.IsLoaded() {
peerLog.Debugf("%s sent a filteradd request with no filter "+
"loaded -- disconnecting", sp)
sp.Disconnect()
return
}
sp.filter.Add(msg.Data)
}
// OnFilterClear is invoked when a peer receives a filterclear bitcoin
// message and is used by remote peers to clear an already loaded bloom filter.
// The peer will be disconnected if a filter is not loaded when this message is
// received or the server is not configured to allow bloom filters.
func (sp *serverPeer) OnFilterClear(_ *peer.Peer, msg *wire.MsgFilterClear) {
// Disconnect and/or ban depending on the node bloom services flag and
// negotiated protocol version.
if !sp.enforceNodeBloomFlag(msg.Command()) {
return
}
if !sp.filter.IsLoaded() {
peerLog.Debugf("%s sent a filterclear request with no "+
"filter loaded -- disconnecting", sp)
sp.Disconnect()
return
}
sp.filter.Unload()
}
// OnFilterLoad is invoked when a peer receives a filterload bitcoin
// message and it used to load a bloom filter that should be used for
// delivering merkle blocks and associated transactions that match the filter.
// The peer will be disconnected if the server is not configured to allow bloom
// filters.
func (sp *serverPeer) OnFilterLoad(_ *peer.Peer, msg *wire.MsgFilterLoad) {
// Disconnect and/or ban depending on the node bloom services flag and
// negotiated protocol version.
if !sp.enforceNodeBloomFlag(msg.Command()) {
return
}
sp.setDisableRelayTx(false)
sp.filter.Reload(msg)
}
// OnGetAddr is invoked when a peer receives a getaddr bitcoin message
// and is used to provide the peer with known addresses from the address
// manager.
func (sp *serverPeer) OnGetAddr(_ *peer.Peer, msg *wire.MsgGetAddr) {
// Don't return any addresses when running on the simulation test
// network. This helps prevent the network from becoming another
// public test network since it will not be able to learn about other
// peers that have not specifically been provided.
if cfg.SimNet {
return
}
// Do not accept getaddr requests from outbound peers. This reduces
// fingerprinting attacks.
if !sp.Inbound() {
peerLog.Debugf("Ignoring getaddr request from outbound peer ",
"%v", sp)
return
}
// Only allow one getaddr request per connection to discourage
// address stamping of inv announcements.
if sp.sentAddrs {
peerLog.Debugf("Ignoring repeated getaddr request from peer ",
"%v", sp)
return
}
sp.sentAddrs = true
// Get the current known addresses from the address manager.
addrCache := sp.server.addrManager.AddressCache()
// Push the addresses.
sp.pushAddrMsg(addrCache)
}
// OnAddr is invoked when a peer receives an addr bitcoin message and is
// used to notify the server about advertised addresses.
func (sp *serverPeer) OnAddr(_ *peer.Peer, msg *wire.MsgAddr) {
// Ignore addresses when running on the simulation test network. This
// helps prevent the network from becoming another public test network
// since it will not be able to learn about other peers that have not
// specifically been provided.
if cfg.SimNet {
return
}
// Ignore old style addresses which don't include a timestamp.
if sp.ProtocolVersion() < wire.NetAddressTimeVersion {
return
}
// A message that has no addresses is invalid.
if len(msg.AddrList) == 0 {
peerLog.Errorf("Command [%s] from %s does not contain any addresses",
msg.Command(), sp)
sp.Disconnect()
return
}
for _, na := range msg.AddrList {
// Don't add more address if we're disconnecting.
if !sp.Connected() {
return
}
// Set the timestamp to 5 days ago if it's more than 24 hours
// in the future so this address is one of the first to be
// removed when space is needed.
now := time.Now()
if na.Timestamp.After(now.Add(time.Minute * 10)) {
na.Timestamp = now.Add(-1 * time.Hour * 24 * 5)
}
// Add address to known addresses for this peer.
sp.addKnownAddresses([]*wire.NetAddress{na})
}
// Add addresses to server address manager. The address manager handles
// the details of things such as preventing duplicate addresses, max
// addresses, and last seen updates.
// XXX bitcoind gives a 2 hour time penalty here, do we want to do the
// same?
sp.server.addrManager.AddAddresses(msg.AddrList, sp.NA())
}
// OnRead is invoked when a peer receives a message and it is used to update
// the bytes received by the server.
func (sp *serverPeer) OnRead(_ *peer.Peer, bytesRead int, msg wire.Message, err error) {
sp.server.AddBytesReceived(uint64(bytesRead))
}
// OnWrite is invoked when a peer sends a message and it is used to update
// the bytes sent by the server.
func (sp *serverPeer) OnWrite(_ *peer.Peer, bytesWritten int, msg wire.Message, err error) {
sp.server.AddBytesSent(uint64(bytesWritten))
}
// randomUint16Number returns a random uint16 in a specified input range. Note
// that the range is in zeroth ordering; if you pass it 1800, you will get
// values from 0 to 1800.
func randomUint16Number(max uint16) uint16 {
// In order to avoid modulo bias and ensure every possible outcome in
// [0, max) has equal probability, the random number must be sampled
// from a random source that has a range limited to a multiple of the
// modulus.
var randomNumber uint16
var limitRange = (math.MaxUint16 / max) * max
for {
binary.Read(rand.Reader, binary.LittleEndian, &randomNumber)
if randomNumber < limitRange {
return (randomNumber % max)
}
}