134 lines
3.6 KiB
Go
134 lines
3.6 KiB
Go
package beacon
|
|
|
|
import (
|
|
"bytes"
|
|
"context"
|
|
"encoding/binary"
|
|
"time"
|
|
|
|
"github.com/filecoin-project/lotus/chain/types"
|
|
"github.com/filecoin-project/specs-actors/actors/abi"
|
|
logging "github.com/ipfs/go-log"
|
|
"golang.org/x/xerrors"
|
|
|
|
"github.com/minio/blake2b-simd"
|
|
)
|
|
|
|
var log = logging.Logger("beacon")
|
|
|
|
type Response struct {
|
|
Entry types.BeaconEntry
|
|
Err error
|
|
}
|
|
|
|
type DrandBeacon interface {
|
|
//RoundTime() uint64
|
|
//StartTime() uint64
|
|
LastEntry() (types.BeaconEntry, error)
|
|
Entry(context.Context, uint64) <-chan Response
|
|
VerifyEntry(types.BeaconEntry, types.BeaconEntry) error
|
|
BeaconRoundsForEpoch(abi.ChainEpoch, types.BeaconEntry) []uint64
|
|
IsEntryForEpoch(e types.BeaconEntry, epoch abi.ChainEpoch, nulls int) (bool, error)
|
|
}
|
|
|
|
func ValidateBlockValues(b DrandBeacon, h *types.BlockHeader, prevEntry types.BeaconEntry) error {
|
|
rounds := b.BeaconRoundsForEpoch(h.Height, prevEntry)
|
|
if len(rounds) != len(h.BeaconEntries) {
|
|
return xerrors.Errorf("mismatch in number of expected beacon entries (exp %d, got %d)", len(rounds), len(h.BeaconEntries))
|
|
}
|
|
|
|
for i, e := range h.BeaconEntries {
|
|
if e.Round != rounds[i] {
|
|
return xerrors.Errorf("entry at index %d did not match expected round (exp %d, got %d)", i, rounds[i], e.Round)
|
|
}
|
|
|
|
if err := b.VerifyEntry(e, prevEntry); err != nil {
|
|
return xerrors.Errorf("beacon entry %d was invalid: %w", i, err)
|
|
}
|
|
prevEntry = e
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func BeaconEntriesForBlock(ctx context.Context, beacon DrandBeacon, round abi.ChainEpoch, prev types.BeaconEntry) ([]types.BeaconEntry, error) {
|
|
start := time.Now()
|
|
|
|
var out []types.BeaconEntry
|
|
for _, ei := range beacon.BeaconRoundsForEpoch(round, prev) {
|
|
rch := beacon.Entry(ctx, ei)
|
|
select {
|
|
case resp := <-rch:
|
|
if resp.Err != nil {
|
|
return nil, xerrors.Errorf("beacon entry request returned error: %w", resp.Err)
|
|
}
|
|
|
|
out = append(out, resp.Entry)
|
|
case <-ctx.Done():
|
|
return nil, xerrors.Errorf("context timed out waiting on beacon entry to come back for round %d: %w", round, ctx.Err())
|
|
}
|
|
}
|
|
|
|
log.Debugw("fetching beacon entries", "took", time.Since(start), "numEntries", len(out))
|
|
return out, nil
|
|
}
|
|
|
|
// Mock beacon assumes that filecoin rounds are 1:1 mapped with the beacon rounds
|
|
type mockBeacon struct {
|
|
interval time.Duration
|
|
}
|
|
|
|
func NewMockBeacon(interval time.Duration) *mockBeacon {
|
|
mb := &mockBeacon{interval: interval}
|
|
|
|
return mb
|
|
}
|
|
|
|
func (mb *mockBeacon) RoundTime() time.Duration {
|
|
return mb.interval
|
|
}
|
|
|
|
func (mb *mockBeacon) LastEntry() (types.BeaconEntry, error) {
|
|
panic("NYI")
|
|
}
|
|
|
|
func (mb *mockBeacon) entryForIndex(index uint64) types.BeaconEntry {
|
|
buf := make([]byte, 8)
|
|
binary.BigEndian.PutUint64(buf, index)
|
|
rval := blake2b.Sum256(buf)
|
|
return types.BeaconEntry{
|
|
Round: index,
|
|
Data: rval[:],
|
|
}
|
|
}
|
|
|
|
func (mb *mockBeacon) Entry(ctx context.Context, index uint64) <-chan Response {
|
|
e := mb.entryForIndex(index)
|
|
out := make(chan Response, 1)
|
|
out <- Response{Entry: e}
|
|
return out
|
|
}
|
|
|
|
func (mb *mockBeacon) VerifyEntry(from types.BeaconEntry, to types.BeaconEntry) error {
|
|
// TODO: cache this, especially for bls
|
|
oe := mb.entryForIndex(from.Round)
|
|
if !bytes.Equal(from.Data, oe.Data) {
|
|
return xerrors.Errorf("mock beacon entry was invalid!")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (mb *mockBeacon) IsEntryForEpoch(e types.BeaconEntry, epoch abi.ChainEpoch, nulls int) (bool, error) {
|
|
return int64(e.Round) <= int64(epoch) && int64(epoch)-int64(nulls) >= int64(e.Round), nil
|
|
}
|
|
|
|
func (mb *mockBeacon) BeaconRoundsForEpoch(epoch abi.ChainEpoch, prevEntry types.BeaconEntry) []uint64 {
|
|
var out []uint64
|
|
for i := prevEntry.Round + 1; i <= uint64(epoch); i++ {
|
|
out = append(out, i)
|
|
}
|
|
return out
|
|
}
|
|
|
|
var _ DrandBeacon = (*mockBeacon)(nil)
|