first pass, ready for review

2020-08-03 12:20:04 -03:00
parent 43491cb7ed
commit 76d40ec408
14 changed files with 1179 additions and 1045 deletions
@@ -0,0 +1,263 @@
+package blocksync
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"time"
+
+	"go.opencensus.io/trace"
+	"golang.org/x/xerrors"
+
+	cborutil "github.com/filecoin-project/go-cbor-util"
+
+	"github.com/filecoin-project/lotus/chain/store"
+	"github.com/filecoin-project/lotus/chain/types"
+
+	"github.com/ipfs/go-cid"
+	inet "github.com/libp2p/go-libp2p-core/network"
+)
+
+
+// BlockSyncService is the component that services BlockSync requests from
+// peers.
+//
+// BlockSync is the basic chain synchronization protocol of Filecoin. BlockSync
+// is an RPC-oriented protocol, with a single operation to request blocks.
+//
+// A request contains a start anchor block (referred to with a CID), and a
+// amount of blocks requested beyond the anchor (including the anchor itself).
+//
+// A client can also pass options, encoded as a 64-bit bitfield. Lotus supports
+// two options at the moment:
+//
+//  - include block contents
+//  - include block messages
+//
+// The response will include a status code, an optional message, and the
+// response payload in case of success. The payload is a slice of serialized
+// tipsets.
+// FIXME: Rename to just `Server` (will be done later, see note on `BlockSync`).
+type BlockSyncService struct {
+	cs *store.ChainStore
+}
+
+func NewBlockSyncService(cs *store.ChainStore) *BlockSyncService {
+	return &BlockSyncService{
+		cs: cs,
+	}
+}
+
+// Entry point of the service, handles `Request`s.
+func (server *BlockSyncService) HandleStream(stream inet.Stream) {
+	ctx, span := trace.StartSpan(context.Background(), "blocksync.HandleStream")
+	defer span.End()
+
+	defer stream.Close() //nolint:errcheck
+
+	var req Request
+	if err := cborutil.ReadCborRPC(bufio.NewReader(stream), &req); err != nil {
+		log.Warnf("failed to read block sync request: %s", err)
+		return
+	}
+	log.Infow("block sync request",
+		"start", req.Head, "len", req.Length)
+
+	resp, err := server.processRequest(ctx, &req)
+	if err != nil {
+		log.Warn("failed to process request: ", err)
+		return
+	}
+
+	_ = stream.SetDeadline(time.Now().Add(WRITE_RES_DEADLINE))
+	if err := cborutil.WriteCborRPC(stream, resp); err != nil {
+		log.Warnw("failed to write back response for handle stream",
+			"err", err, "peer", stream.Conn().RemotePeer())
+		return
+	}
+}
+
+// Validate and service the request. We return either a protocol
+// response or an internal error. The protocol response may signal
+// a protocol error itself (e.g., invalid request).
+func (server *BlockSyncService) processRequest(
+	ctx context.Context,
+	req *Request,
+) (*Response, error) {
+	validReq, errResponse := validateRequest(ctx, req)
+	if errResponse != nil {
+		// The request did not pass validation, return the response
+		//  indicating it.
+		return errResponse, nil
+	}
+
+	return server.serviceRequest(ctx, validReq)
+}
+
+// Validate request. We either return a `validatedRequest`, or an error
+// `Response` indicating why we can't process it. We do not return any
+// internal errors here, we just signal protocol ones.
+func validateRequest(
+	ctx context.Context,
+	req *Request,
+) ( *validatedRequest, *Response) {
+	_, span := trace.StartSpan(ctx, "blocksync.ValidateRequest")
+	defer span.End()
+
+	validReq := validatedRequest{}
+
+	validReq.options = parseOptions(req.Options)
+	if validReq.options.noOptionsSet() {
+		return nil, &Response{
+			Status:       BadRequest,
+			ErrorMessage: "no options set",
+		}
+	}
+
+	validReq.length = req.Length
+	if validReq.length > MaxRequestLength {
+		return nil, &Response{
+			Status:       BadRequest,
+			ErrorMessage: fmt.Sprintf("request length over maximum allowed (%d)",
+				MaxRequestLength),
+		}
+	}
+	if validReq.length == 0 {
+		return nil, &Response{
+			Status:       BadRequest,
+			ErrorMessage: "invalid request length of zero",
+		}
+	}
+
+	if len(req.Head) == 0 {
+		return nil, &Response{
+			Status:       BadRequest,
+			ErrorMessage: "no cids in request",
+		}
+	}
+	validReq.head = types.NewTipSetKey(req.Head...)
+
+	// FIXME: Add as a defer at the start.
+	span.AddAttributes(
+		trace.BoolAttribute("blocks", validReq.options.IncludeHeaders),
+		trace.BoolAttribute("messages", validReq.options.IncludeMessages),
+		trace.Int64Attribute("reqlen", int64(validReq.length)),
+	)
+
+	return &validReq, nil
+}
+
+func (server *BlockSyncService) serviceRequest(
+	ctx context.Context,
+	req *validatedRequest,
+	) (*Response, error) {
+	_, span := trace.StartSpan(ctx, "blocksync.ServiceRequest")
+	defer span.End()
+
+	chain, err := collectChainSegment(server.cs, req)
+	if err != nil {
+		log.Warn("block sync request: collectChainSegment failed: ", err)
+		return &Response{
+			Status:       InternalError,
+			ErrorMessage: err.Error(),
+		}, nil
+	}
+
+	status := Ok
+	if len(chain) < int(req.length) {
+		status = Partial
+	}
+
+	return &Response{
+		Chain:  chain,
+		Status: status,
+	}, nil
+}
+
+func collectChainSegment(
+	cs *store.ChainStore,
+	req *validatedRequest,
+	) ([]*BSTipSet, error) {
+	var bstips []*BSTipSet
+
+	cur := req.head
+	for {
+		var bst BSTipSet
+		ts, err := cs.LoadTipSet(cur)
+		if err != nil {
+			return nil, xerrors.Errorf("failed loading tipset %s: %w", cur, err)
+		}
+
+		if req.options.IncludeHeaders {
+			bst.Blocks = ts.Blocks()
+		}
+
+		if req.options.IncludeMessages {
+			bmsgs, bmincl, smsgs, smincl, err := gatherMessages(cs, ts)
+			if err != nil {
+				return nil, xerrors.Errorf("gather messages failed: %w", err)
+			}
+
+			// FIXME: Pass the response to the `gatherMessages` and set all this there.
+			bst.Messages = &CompactedMessages{}
+			bst.Messages.Bls = bmsgs
+			bst.Messages.BlsIncludes = bmincl
+			bst.Messages.Secpk = smsgs
+			bst.Messages.SecpkIncludes = smincl
+		}
+
+		bstips = append(bstips, &bst)
+
+		// If we collected the length requested or if we reached the
+		// start (genesis), then stop.
+		if uint64(len(bstips)) >= req.length || ts.Height() == 0 {
+			return bstips, nil
+		}
+
+		cur = ts.Parents()
+	}
+}
+
+func gatherMessages(cs *store.ChainStore, ts *types.TipSet) ([]*types.Message, [][]uint64, []*types.SignedMessage, [][]uint64, error) {
+	blsmsgmap := make(map[cid.Cid]uint64)
+	secpkmsgmap := make(map[cid.Cid]uint64)
+	var secpkmsgs []*types.SignedMessage
+	var blsmsgs []*types.Message
+	var secpkincl, blsincl [][]uint64
+
+	for _, block := range ts.Blocks() {
+		bmsgs, smsgs, err := cs.MessagesForBlock(block)
+		if err != nil {
+			return nil, nil, nil, nil, err
+		}
+
+		// FIXME: DRY. Use `chain.Message` interface.
+		bmi := make([]uint64, 0, len(bmsgs))
+		for _, m := range bmsgs {
+			i, ok := blsmsgmap[m.Cid()]
+			if !ok {
+				i = uint64(len(blsmsgs))
+				blsmsgs = append(blsmsgs, m)
+				blsmsgmap[m.Cid()] = i
+			}
+
+			bmi = append(bmi, i)
+		}
+		blsincl = append(blsincl, bmi)
+
+		smi := make([]uint64, 0, len(smsgs))
+		for _, m := range smsgs {
+			i, ok := secpkmsgmap[m.Cid()]
+			if !ok {
+				i = uint64(len(secpkmsgs))
+				secpkmsgs = append(secpkmsgs, m)
+				secpkmsgmap[m.Cid()] = i
+			}
+
+			smi = append(smi, i)
+		}
+		secpkincl = append(secpkincl, smi)
+	}
+
+	return blsmsgs, blsincl, secpkmsgs, secpkincl, nil
+}