lnd.xprv/channeldb/peers.go
carla a550ca3d64
multi: store peer flap rate on disk on best effort basis
Since we will use peer flap rate to determine how we rate limit, we
store this value on disk per peer per channel. This allows us to
restart with memory of our peers past behaviour, so we don't give badly
behaving peers have a fresh start on restart. Last flap timestamp is
stored with our flap count so that we can degrade this all time flap
count over time for peers that have not recently flapped.
2020-09-08 13:49:46 +02:00

122 lines
2.9 KiB
Go

package channeldb
import (
"bytes"
"errors"
"fmt"
"time"
"github.com/btcsuite/btcwallet/walletdb"
"github.com/lightningnetwork/lnd/routing/route"
)
var (
// peersBucket is the name of a top level bucket in which we store
// information about our peers. Information for different peers is
// stored in buckets keyed by their public key.
//
//
// peers-bucket
// |
// |-- <peer-pubkey>
// | |--flap-count-key: <ts><flap count>
// |
// |-- <peer-pubkey>
// | |--flap-count-key: <ts><flap count>
peersBucket = []byte("peers-bucket")
// flapCountKey is a key used in the peer pubkey sub-bucket that stores
// the timestamp of a peer's last flap count and its all time flap
// count.
flapCountKey = []byte("flap-count")
)
var (
// ErrNoPeerBucket is returned when we try to read entries for a peer
// that is not tracked.
ErrNoPeerBucket = errors.New("peer bucket not found")
)
// FlapCount contains information about a peer's flap count.
type FlapCount struct {
// Count provides the total flap count for a peer.
Count uint32
// LastFlap is the timestamp of the last flap recorded for a peer.
LastFlap time.Time
}
// WriteFlapCounts writes the flap count for a set of peers to disk, creating a
// bucket for the peer's pubkey if necessary. Note that this function overwrites
// the current value.
func (d *DB) WriteFlapCounts(flapCounts map[route.Vertex]*FlapCount) error {
return d.Update(func(tx walletdb.ReadWriteTx) error {
// Run through our set of flap counts and record them for
// each peer, creating a bucket for the peer pubkey if required.
for peer, flapCount := range flapCounts {
peers := tx.ReadWriteBucket(peersBucket)
peerBucket, err := peers.CreateBucketIfNotExists(
peer[:],
)
if err != nil {
return err
}
var b bytes.Buffer
err = serializeTime(&b, flapCount.LastFlap)
if err != nil {
return err
}
if err = WriteElement(&b, flapCount.Count); err != nil {
return err
}
err = peerBucket.Put(flapCountKey, b.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// ReadFlapCount attempts to read the flap count for a peer, failing if the
// peer is not found or we do not have flap count stored.
func (d *DB) ReadFlapCount(pubkey route.Vertex) (*FlapCount, error) {
var flapCount FlapCount
if err := d.View(func(tx walletdb.ReadTx) error {
peers := tx.ReadBucket(peersBucket)
peerBucket := peers.NestedReadBucket(pubkey[:])
if peerBucket == nil {
return ErrNoPeerBucket
}
flapBytes := peerBucket.Get(flapCountKey)
if flapBytes == nil {
return fmt.Errorf("flap count not recorded for: %v",
pubkey)
}
var (
err error
r = bytes.NewReader(flapBytes)
)
flapCount.LastFlap, err = deserializeTime(r)
if err != nil {
return err
}
return ReadElements(r, &flapCount.Count)
}); err != nil {
return nil, err
}
return &flapCount, nil
}