847b064461
In this commit, we add a new store within the database that'll be responsible for storing gossip messages which we need to reliably send to peers. This aims to replace the current messageStore that exists within the gossiper, so much of this logic is borrowed from there. One of the main differences between the two is that we now index messages with a new key format in which we take into account the message's type. This allows us to store different messages for a specific channel with a peer. The old key format is still supported in order to prevent a database migration.
295 lines
8.0 KiB
Go
295 lines
8.0 KiB
Go
package discovery
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"fmt"
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"github.com/coreos/bbolt"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/lnwire"
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)
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var (
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// messageStoreBucket is a key used to create a top level bucket in the
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// gossiper database, used for storing messages that are to be sent to
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// peers. Upon restarts, these messages will be read and resent to their
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// respective peers.
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//
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// maps:
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// pubKey (33 bytes) + msgShortChanID (8 bytes) + msgType (2 bytes) -> msg
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messageStoreBucket = []byte("message-store")
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// ErrUnsupportedMessage is an error returned when we attempt to add a
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// message to the store that is not supported.
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ErrUnsupportedMessage = errors.New("unsupported message type")
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// ErrCorruptedMessageStore indicates that the on-disk bucketing
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// structure has altered since the gossip message store instance was
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// initialized.
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ErrCorruptedMessageStore = errors.New("gossip message store has been " +
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"corrupted")
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)
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// GossipMessageStore is a store responsible for storing gossip messages which
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// we should reliably send to our peers.
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type GossipMessageStore interface {
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// AddMessage adds a message to the store for this peer.
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AddMessage(lnwire.Message, [33]byte) error
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// DeleteMessage deletes a message from the store for this peer.
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DeleteMessage(lnwire.Message, [33]byte) error
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// Messages returns the total set of messages that exist within the
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// store for all peers.
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Messages() (map[[33]byte][]lnwire.Message, error)
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// Peers returns the public key of all peers with messages within the
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// store.
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Peers() (map[[33]byte]struct{}, error)
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// MessagesForPeer returns the set of messages that exists within the
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// store for the given peer.
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MessagesForPeer([33]byte) ([]lnwire.Message, error)
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}
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// MessageStore is an implementation of the GossipMessageStore interface backed
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// by a channeldb instance. By design, this store will only keep the latest
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// version of a message (like in the case of multiple ChannelUpdate's) for a
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// channel with a peer.
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type MessageStore struct {
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db *channeldb.DB
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}
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// A compile-time assertion to ensure messageStore implements the
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// GossipMessageStore interface.
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var _ GossipMessageStore = (*MessageStore)(nil)
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// NewMessageStore creates a new message store backed by a channeldb instance.
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func NewMessageStore(db *channeldb.DB) (*MessageStore, error) {
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err := db.Update(func(tx *bbolt.Tx) error {
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_, err := tx.CreateBucketIfNotExists(messageStoreBucket)
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return err
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})
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if err != nil {
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return nil, fmt.Errorf("unable to create required buckets: %v",
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err)
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}
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return &MessageStore{db}, nil
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}
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// msgShortChanID retrieves the short channel ID of the message.
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func msgShortChanID(msg lnwire.Message) (lnwire.ShortChannelID, error) {
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var shortChanID lnwire.ShortChannelID
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switch msg := msg.(type) {
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case *lnwire.AnnounceSignatures:
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shortChanID = msg.ShortChannelID
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case *lnwire.ChannelUpdate:
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shortChanID = msg.ShortChannelID
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default:
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return shortChanID, ErrUnsupportedMessage
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}
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return shortChanID, nil
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}
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// messageStoreKey constructs the database key for the message to be stored.
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func messageStoreKey(msg lnwire.Message, peerPubKey [33]byte) ([]byte, error) {
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shortChanID, err := msgShortChanID(msg)
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if err != nil {
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return nil, err
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}
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var k [33 + 8 + 2]byte
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copy(k[:33], peerPubKey[:])
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binary.BigEndian.PutUint64(k[33:41], shortChanID.ToUint64())
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binary.BigEndian.PutUint16(k[41:43], uint16(msg.MsgType()))
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return k[:], nil
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}
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// AddMessage adds a message to the store for this peer.
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func (s *MessageStore) AddMessage(msg lnwire.Message, peerPubKey [33]byte) error {
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// Construct the key for which we'll find this message with in the store.
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msgKey, err := messageStoreKey(msg, peerPubKey)
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if err != nil {
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return err
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}
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// Serialize the message with its wire encoding.
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var b bytes.Buffer
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if _, err := lnwire.WriteMessage(&b, msg, 0); err != nil {
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return err
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}
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return s.db.Batch(func(tx *bbolt.Tx) error {
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messageStore := tx.Bucket(messageStoreBucket)
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if messageStore == nil {
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return ErrCorruptedMessageStore
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}
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return messageStore.Put(msgKey, b.Bytes())
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})
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}
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// DeleteMessage deletes a message from the store for this peer.
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func (s *MessageStore) DeleteMessage(msg lnwire.Message,
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peerPubKey [33]byte) error {
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// Construct the key for which we'll find this message with in the
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// store.
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msgKey, err := messageStoreKey(msg, peerPubKey)
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if err != nil {
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return err
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}
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return s.db.Batch(func(tx *bbolt.Tx) error {
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messageStore := tx.Bucket(messageStoreBucket)
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if messageStore == nil {
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return ErrCorruptedMessageStore
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}
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// In the event that we're attempting to delete a ChannelUpdate
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// from the store, we'll make sure that we're actually deleting
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// the correct one as it can be overwritten.
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if msg, ok := msg.(*lnwire.ChannelUpdate); ok {
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// Deleting a value from a bucket that doesn't exist
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// acts as a NOP, so we'll return if a message doesn't
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// exist under this key.
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v := messageStore.Get(msgKey)
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if v == nil {
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return nil
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}
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dbMsg, err := lnwire.ReadMessage(bytes.NewReader(v), 0)
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if err != nil {
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return err
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}
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// If the timestamps don't match, then the update stored
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// should be the latest one, so we'll avoid deleting it.
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if msg.Timestamp != dbMsg.(*lnwire.ChannelUpdate).Timestamp {
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return nil
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}
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}
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return messageStore.Delete(msgKey)
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})
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}
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// readMessage reads a message from its serialized form and ensures its
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// supported by the current version of the message store.
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func readMessage(msgBytes []byte) (lnwire.Message, error) {
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msg, err := lnwire.ReadMessage(bytes.NewReader(msgBytes), 0)
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if err != nil {
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return nil, err
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}
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// Check if the message is supported by the store. We can reuse the
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// check for ShortChannelID as its a dependency on messages stored.
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if _, err := msgShortChanID(msg); err != nil {
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return nil, err
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}
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return msg, nil
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}
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// Messages returns the total set of messages that exist within the store for
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// all peers.
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func (s *MessageStore) Messages() (map[[33]byte][]lnwire.Message, error) {
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msgs := make(map[[33]byte][]lnwire.Message)
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err := s.db.View(func(tx *bbolt.Tx) error {
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messageStore := tx.Bucket(messageStoreBucket)
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if messageStore == nil {
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return ErrCorruptedMessageStore
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}
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return messageStore.ForEach(func(k, v []byte) error {
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var pubKey [33]byte
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copy(pubKey[:], k[:33])
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// Deserialize the message from its raw bytes and filter
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// out any which are not currently supported by the
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// store.
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msg, err := readMessage(v)
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if err == ErrUnsupportedMessage {
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return nil
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}
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if err != nil {
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return err
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}
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msgs[pubKey] = append(msgs[pubKey], msg)
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return nil
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})
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})
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if err != nil {
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return nil, err
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}
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return msgs, nil
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}
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// MessagesForPeer returns the set of messages that exists within the store for
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// the given peer.
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func (s *MessageStore) MessagesForPeer(
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peerPubKey [33]byte) ([]lnwire.Message, error) {
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var msgs []lnwire.Message
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err := s.db.View(func(tx *bbolt.Tx) error {
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messageStore := tx.Bucket(messageStoreBucket)
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if messageStore == nil {
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return ErrCorruptedMessageStore
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}
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c := messageStore.Cursor()
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k, v := c.Seek(peerPubKey[:])
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for ; bytes.HasPrefix(k, peerPubKey[:]); k, v = c.Next() {
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// Deserialize the message from its raw bytes and filter
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// out any which are not currently supported by the
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// store.
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msg, err := readMessage(v)
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if err == ErrUnsupportedMessage {
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continue
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}
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if err != nil {
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return err
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}
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msgs = append(msgs, msg)
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}
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return nil
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})
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if err != nil {
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return nil, err
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}
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return msgs, nil
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}
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// Peers returns the public key of all peers with messages within the store.
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func (s *MessageStore) Peers() (map[[33]byte]struct{}, error) {
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peers := make(map[[33]byte]struct{})
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err := s.db.View(func(tx *bbolt.Tx) error {
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messageStore := tx.Bucket(messageStoreBucket)
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if messageStore == nil {
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return ErrCorruptedMessageStore
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}
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return messageStore.ForEach(func(k, _ []byte) error {
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var pubKey [33]byte
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copy(pubKey[:], k[:33])
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peers[pubKey] = struct{}{}
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return nil
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})
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})
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if err != nil {
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return nil, err
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}
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return peers, nil
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}
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