90 lines
2.4 KiB
Go
90 lines
2.4 KiB
Go
package beacon
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import (
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"context"
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"time"
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"github.com/filecoin-project/lotus/chain/types"
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"github.com/filecoin-project/specs-actors/actors/abi"
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logging "github.com/ipfs/go-log"
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"golang.org/x/xerrors"
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)
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var log = logging.Logger("beacon")
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type Response struct {
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Entry types.BeaconEntry
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Err error
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}
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type RandomBeacon interface {
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Entry(context.Context, uint64) <-chan Response
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VerifyEntry(types.BeaconEntry, types.BeaconEntry) error
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MaxBeaconRoundForEpoch(abi.ChainEpoch, types.BeaconEntry) uint64
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}
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func ValidateBlockValues(b RandomBeacon, h *types.BlockHeader, prevEntry types.BeaconEntry) error {
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maxRound := b.MaxBeaconRoundForEpoch(h.Height, prevEntry)
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if maxRound == prevEntry.Round {
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if len(h.BeaconEntries) != 0 {
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return xerrors.Errorf("expected not to have any beacon entries in this block, got %d", len(h.BeaconEntries))
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}
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return nil
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}
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last := h.BeaconEntries[len(h.BeaconEntries)-1]
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if last.Round != maxRound {
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return xerrors.Errorf("expected final beacon entry in block to be at round %d, got %d", maxRound, last.Round)
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}
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for i, e := range h.BeaconEntries {
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if err := b.VerifyEntry(e, prevEntry); err != nil {
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return xerrors.Errorf("beacon entry %d (%d - %x (%d)) was invalid: %w", i, e.Round, e.Data, len(e.Data), err)
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}
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prevEntry = e
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}
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return nil
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}
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func BeaconEntriesForBlock(ctx context.Context, beacon RandomBeacon, round abi.ChainEpoch, prev types.BeaconEntry) ([]types.BeaconEntry, error) {
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start := time.Now()
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maxRound := beacon.MaxBeaconRoundForEpoch(round, prev)
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if maxRound == prev.Round {
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return nil, nil
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}
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// TODO: this is a sketchy way to handle the genesis block not having a beacon entry
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if prev.Round == 0 {
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prev.Round = maxRound - 1
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}
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cur := maxRound
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var out []types.BeaconEntry
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for cur > prev.Round {
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rch := beacon.Entry(ctx, cur)
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select {
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case resp := <-rch:
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if resp.Err != nil {
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return nil, xerrors.Errorf("beacon entry request returned error: %w", resp.Err)
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}
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out = append(out, resp.Entry)
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cur = resp.Entry.Round - 1
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case <-ctx.Done():
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return nil, xerrors.Errorf("context timed out waiting on beacon entry to come back for round %d: %w", round, ctx.Err())
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}
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}
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log.Debugw("fetching beacon entries", "took", time.Since(start), "numEntries", len(out))
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reverse(out)
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return out, nil
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}
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func reverse(arr []types.BeaconEntry) {
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for i := 0; i < len(arr)/2; i++ {
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arr[i], arr[len(arr)-(1+i)] = arr[len(arr)-(1+i)], arr[i]
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}
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}
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