lnd.xprv/channeldb/nodes.go

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package channeldb
import (
"bytes"
"fmt"
"io"
"net"
"time"
"github.com/boltdb/bolt"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/wire"
)
var (
// nodeInfoBucket stores meta-data pertaining to nodes that we've had
// direct channel-based correspondence with. This bucket allows one to
// query for all open channels pertaining to the node by exploring each
// node's sub-bucket within the openChanBucket.
nodeInfoBucket = []byte("nib")
)
// LinkNode stores meta-data related to node's that we have/had a direct
// channel open with. Information such as the Bitcoin network the node
// advertised, and its identity public key are also stored. Additionally, this
// struct and the bucket its stored within have store data similar to that of
// Bitcion's addrmanager. The TCP address information stored within the struct
// can be used to establish persistent connections will all channel
// counter-parties on daemon startup.
//
// TODO(roasbeef): also add current OnionKey plus rotation schedule?
// TODO(roasbeef): add bitfield for supported services
// * possibly add a wire.NetAddress type, type
type LinkNode struct {
// Network indicates the Bitcoin network that the LinkNode advertises
// for incoming channel creation.
Network wire.BitcoinNet
// IdentityPub is the node's current identity public key. Any
// channel/topology related information received by this node MUST be
// signed by this public key.
IdentityPub *btcec.PublicKey
// LastSeen tracks the last time this node was seen within the network.
// A node should be marked as seen if the daemon either is able to
// establish an outgoing connection to the node or receives a new
// incoming connection from the node. This timestamp (stored in unix
// epoch) may be used within a heuristic which aims to determine when a
// channel should be unilaterally closed due to inactivity.
//
// TODO(roasbeef): replace with block hash/height?
// * possibly add a time-value metric into the heuristic?
LastSeen time.Time
// Addresses is a list of IP address in which either we were able to
// reach the node over in the past, OR we received an incoming
// authenticated connection for the stored identity public key.
//
// TODO(roasbeef): also need to support hidden service addrs
Addresses []*net.TCPAddr
db *DB
}
// NewLinkNode creates a new LinkNode from the provided parameters, which is
// backed by an instance of channeldb.
func (db *DB) NewLinkNode(bitNet wire.BitcoinNet, pub *btcec.PublicKey,
addr *net.TCPAddr) *LinkNode {
return &LinkNode{
Network: bitNet,
IdentityPub: pub,
LastSeen: time.Now(),
Addresses: []*net.TCPAddr{addr},
db: db,
}
}
// UpdateLastSeen updates the last time this node was directly encountered on
// the Lightning Network.
func (l *LinkNode) UpdateLastSeen(lastSeen time.Time) error {
l.LastSeen = lastSeen
return l.Sync()
}
// AddAddress appends the specified TCP address to the list of known addresses
// this node is/was known to be reachable at.
func (l *LinkNode) AddAddress(addr *net.TCPAddr) error {
for _, a := range l.Addresses {
if a.String() == addr.String() {
return nil
}
}
l.Addresses = append(l.Addresses, addr)
return l.Sync()
}
// Sync performs a full database sync which writes the current up-to-date data
// within the struct to the database.
func (l *LinkNode) Sync() error {
// Finally update the database by storing the link node and updating
// any relevant indexes.
return l.db.store.Update(func(tx *bolt.Tx) error {
nodeMetaBucket := tx.Bucket(nodeInfoBucket)
if nodeInfoBucket == nil {
return fmt.Errorf("node bucket not created")
}
return putLinkNode(nodeMetaBucket, l)
})
}
// putLinkNode serializes then writes the encoded version of the passed link
// node into the nodeMetaBucket. This function is provided in order to allow
// the ability to re-use a database transaction across many operations.
func putLinkNode(nodeMetaBucket *bolt.Bucket, l *LinkNode) error {
// First serialize the LinkNode into its raw-bytes encoding.
var b bytes.Buffer
if err := serializeLinkNode(&b, l); err != nil {
return err
}
// Finally insert the link-node into the node meta-data bucket keyed
// according to the its pubkey serialized in compressed form.
nodePub := l.IdentityPub.SerializeCompressed()
return nodeMetaBucket.Put(nodePub, b.Bytes())
}
// FetchLinkNode attempts to lookup the data for a LinkNode based on a target
// identity public key. If a particular LinkNode for the passed identity public
// key cannot be found, then ErrNodeNotFound if returned.
func (db *DB) FetchLinkNode(identity *btcec.PublicKey) (*LinkNode, error) {
var (
node *LinkNode
err error
)
err = db.store.View(func(tx *bolt.Tx) error {
// First fetch the bucket for storing node meta-data, bailing
// out early if it hasn't been created yet.
nodeMetaBucket := tx.Bucket(nodeInfoBucket)
if nodeInfoBucket == nil {
return fmt.Errorf("node bucket not created")
}
// If a link node for that particular public key cannot be
// located, then exit early with a ErrNodeNotFound.
pubKey := identity.SerializeCompressed()
nodeBytes := nodeMetaBucket.Get(pubKey)
if nodeBytes == nil {
return ErrNodeNotFound
}
// Finally, decode an allocate a fresh LinkNode object to be
// returned to the caller.
nodeReader := bytes.NewReader(nodeBytes)
node, err = deserializeLinkNode(nodeReader)
if err != nil {
return err
}
return nil
})
if err != nil {
return nil, err
}
return node, nil
}
// FetchAllLinkNodes attempts to fetch all active LinkNodes from the database.
// If there haven't been any channels explicitly linked to LinkNodes written to
// the database, then this function will return an empty slice.
func (db *DB) FetchAllLinkNodes() ([]*LinkNode, error) {
var linkNodes []*LinkNode
err := db.store.View(func(tx *bolt.Tx) error {
nodeMetaBucket := tx.Bucket(nodeInfoBucket)
if nodeInfoBucket == nil {
return fmt.Errorf("node bucket not created")
}
return nodeMetaBucket.ForEach(func(k, v []byte) error {
nodeReader := bytes.NewReader(v)
linkNode, err := deserializeLinkNode(nodeReader)
if err != nil {
return err
}
linkNodes = append(linkNodes, linkNode)
return nil
})
return nil
})
if err != nil {
return nil, err
}
return linkNodes, nil
}
func serializeLinkNode(w io.Writer, l *LinkNode) error {
var buf [8]byte
byteOrder.PutUint32(buf[:4], uint32(l.Network))
if _, err := w.Write(buf[:4]); err != nil {
return err
}
serializedID := l.IdentityPub.SerializeCompressed()
if _, err := w.Write(serializedID); err != nil {
return err
}
seenUnix := uint64(l.LastSeen.Unix())
byteOrder.PutUint64(buf[:], seenUnix)
if _, err := w.Write(buf[:]); err != nil {
return err
}
numAddrs := uint32(len(l.Addresses))
byteOrder.PutUint32(buf[:4], numAddrs)
if _, err := w.Write(buf[:4]); err != nil {
return err
}
for _, addr := range l.Addresses {
addrString := addr.String()
if err := wire.WriteVarString(w, 0, addrString); err != nil {
return err
}
}
return nil
}
func deserializeLinkNode(r io.Reader) (*LinkNode, error) {
var (
err error
buf [8]byte
)
node := &LinkNode{}
if _, err := io.ReadFull(r, buf[:4]); err != nil {
return nil, err
}
node.Network = wire.BitcoinNet(byteOrder.Uint32(buf[:4]))
var pub [33]byte
if _, err := io.ReadFull(r, pub[:]); err != nil {
return nil, err
}
node.IdentityPub, err = btcec.ParsePubKey(pub[:], btcec.S256())
if err != nil {
return nil, err
}
if _, err := io.ReadFull(r, buf[:]); err != nil {
return nil, err
}
node.LastSeen = time.Unix(int64(byteOrder.Uint64(buf[:])), 0)
if _, err := io.ReadFull(r, buf[:4]); err != nil {
return nil, err
}
numAddrs := byteOrder.Uint32(buf[:4])
node.Addresses = make([]*net.TCPAddr, numAddrs)
for i := uint32(0); i < numAddrs; i++ {
addrString, err := wire.ReadVarString(r, 0)
if err != nil {
return nil, err
}
addr, err := net.ResolveTCPAddr("tcp", addrString)
if err != nil {
return nil, err
}
node.Addresses[i] = addr
}
return node, nil
}