1 files changed, 232 insertions, 0 deletions
diff --git a/internal/db/trillian.go b/internal/db/trillian.go
new file mode 100644
index 0000000..e8a9945
--- /dev/null
+++ b/internal/db/trillian.go
@@ -0,0 +1,232 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"git.sigsum.org/sigsum-go/pkg/log"
+	"git.sigsum.org/sigsum-go/pkg/merkle"
+	"git.sigsum.org/sigsum-go/pkg/requests"
+	"git.sigsum.org/sigsum-go/pkg/types"
+	"github.com/google/trillian"
+	trillianTypes "github.com/google/trillian/types"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// TrillianClient implements the Client interface for Trillian's gRPC backend
+type TrillianClient struct {
+	// TreeID is a Merkle tree identifier that Trillian uses
+	TreeID int64
+
+	// GRPC is a Trillian gRPC client
+	GRPC trillian.TrillianLogClient
+}
+
+// AddLeaf adds a leaf to the tree and returns true if the leaf has
+// been sequenced into the tree of size treeSize.
+func (c *TrillianClient) AddLeaf(ctx context.Context, req *requests.Leaf, treeSize uint64) (bool, error) {
+	leaf := types.Leaf{
+		Statement: types.Statement{
+			ShardHint: req.ShardHint,
+			Checksum:  *merkle.HashFn(req.Message[:]),
+		},
+		Signature: req.Signature,
+		KeyHash:   *merkle.HashFn(req.PublicKey[:]),
+	}
+	serialized := leaf.ToBinary()
+
+	log.Debug("queueing leaf request: %x", merkle.HashLeafNode(serialized))
+	_, err := c.GRPC.QueueLeaf(ctx, &trillian.QueueLeafRequest{
+		LogId: c.TreeID,
+		Leaf: &trillian.LogLeaf{
+			LeafValue: serialized,
+		},
+	})
+	switch status.Code(err) {
+	case codes.OK:
+	case codes.AlreadyExists:
+	default:
+		log.Warning("gRPC error: %v", err)
+		return false, fmt.Errorf("back-end failure")
+	}
+	_, err = c.GetInclusionProof(ctx, &requests.InclusionProof{treeSize, *merkle.HashLeafNode(serialized)})
+	return err == nil, nil
+}
+
+// AddSequencedLeaves adds a set of already sequenced leaves to the tree.
+func (c *TrillianClient) AddSequencedLeaves(ctx context.Context, leaves types.Leaves, index int64) error {
+	trilLeaves := make([]*trillian.LogLeaf, len(leaves))
+	for i, leaf := range leaves {
+		trilLeaves[i] = &trillian.LogLeaf{
+			LeafValue: leaf.ToBinary(),
+			LeafIndex: index + int64(i),
+		}
+	}
+
+	req := trillian.AddSequencedLeavesRequest{
+		LogId:  c.TreeID,
+		Leaves: trilLeaves,
+	}
+	log.Debug("adding sequenced leaves: count %d", len(trilLeaves))
+	var err error
+	for wait := 1; wait < 30; wait *= 2 {
+		var rsp *trillian.AddSequencedLeavesResponse
+		rsp, err = c.GRPC.AddSequencedLeaves(ctx, &req)
+		switch status.Code(err) {
+		case codes.ResourceExhausted:
+			log.Info("waiting %d seconds before retrying to add %d leaves, reason: %v", wait, len(trilLeaves), err)
+			time.Sleep(time.Second * time.Duration(wait))
+			continue
+		case codes.OK:
+			if rsp == nil {
+				return fmt.Errorf("GRPC.AddSequencedLeaves no response")
+			}
+			// FIXME: check rsp.Results.QueuedLogLeaf
+			return nil
+		default:
+			return fmt.Errorf("GRPC.AddSequencedLeaves error: %v", err)
+		}
+	}
+
+	return fmt.Errorf("giving up on adding %d leaves", len(trilLeaves))
+}
+
+func (c *TrillianClient) GetTreeHead(ctx context.Context) (*types.TreeHead, error) {
+	rsp, err := c.GRPC.GetLatestSignedLogRoot(ctx, &trillian.GetLatestSignedLogRootRequest{
+		LogId: c.TreeID,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if rsp.SignedLogRoot == nil {
+		return nil, fmt.Errorf("no signed log root")
+	}
+	if rsp.SignedLogRoot.LogRoot == nil {
+		return nil, fmt.Errorf("no log root")
+	}
+	var r trillianTypes.LogRootV1
+	if err := r.UnmarshalBinary(rsp.SignedLogRoot.LogRoot); err != nil {
+		return nil, fmt.Errorf("no log root: unmarshal failed: %v", err)
+	}
+	if len(r.RootHash) != merkle.HashSize {
+		return nil, fmt.Errorf("unexpected hash length: %d", len(r.RootHash))
+	}
+	return treeHeadFromLogRoot(&r), nil
+}
+
+func (c *TrillianClient) GetConsistencyProof(ctx context.Context, req *requests.ConsistencyProof) (*types.ConsistencyProof, error) {
+	rsp, err := c.GRPC.GetConsistencyProof(ctx, &trillian.GetConsistencyProofRequest{
+		LogId:          c.TreeID,
+		FirstTreeSize:  int64(req.OldSize),
+		SecondTreeSize: int64(req.NewSize),
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if rsp.Proof == nil {
+		return nil, fmt.Errorf("no consistency proof")
+	}
+	if len(rsp.Proof.Hashes) == 0 {
+		return nil, fmt.Errorf("not a consistency proof: empty")
+	}
+	path, err := nodePathFromHashes(rsp.Proof.Hashes)
+	if err != nil {
+		return nil, fmt.Errorf("not a consistency proof: %v", err)
+	}
+	return &types.ConsistencyProof{
+		OldSize: req.OldSize,
+		NewSize: req.NewSize,
+		Path:    path,
+	}, nil
+}
+
+func (c *TrillianClient) GetInclusionProof(ctx context.Context, req *requests.InclusionProof) (*types.InclusionProof, error) {
+	rsp, err := c.GRPC.GetInclusionProofByHash(ctx, &trillian.GetInclusionProofByHashRequest{
+		LogId:           c.TreeID,
+		LeafHash:        req.LeafHash[:],
+		TreeSize:        int64(req.TreeSize),
+		OrderBySequence: true,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if len(rsp.Proof) != 1 {
+		return nil, fmt.Errorf("bad proof count: %d", len(rsp.Proof))
+	}
+	proof := rsp.Proof[0]
+	if len(proof.Hashes) == 0 {
+		return nil, fmt.Errorf("not an inclusion proof: empty")
+	}
+	path, err := nodePathFromHashes(proof.Hashes)
+	if err != nil {
+		return nil, fmt.Errorf("not an inclusion proof: %v", err)
+	}
+	return &types.InclusionProof{
+		TreeSize:  req.TreeSize,
+		LeafIndex: uint64(proof.LeafIndex),
+		Path:      path,
+	}, nil
+}
+
+func (c *TrillianClient) GetLeaves(ctx context.Context, req *requests.Leaves) (*types.Leaves, error) {
+	rsp, err := c.GRPC.GetLeavesByRange(ctx, &trillian.GetLeavesByRangeRequest{
+		LogId:      c.TreeID,
+		StartIndex: int64(req.StartSize),
+		Count:      int64(req.EndSize-req.StartSize) + 1,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return nil, fmt.Errorf("no response")
+	}
+	if got, want := len(rsp.Leaves), int(req.EndSize-req.StartSize+1); got != want {
+		return nil, fmt.Errorf("unexpected number of leaves: %d", got)
+	}
+	var list types.Leaves = make([]types.Leaf, 0, len(rsp.Leaves))
+	for i, leaf := range rsp.Leaves {
+		leafIndex := int64(req.StartSize + uint64(i))
+		if leafIndex != leaf.LeafIndex {
+			return nil, fmt.Errorf("unexpected leaf(%d): got index %d", leafIndex, leaf.LeafIndex)
+		}
+
+		var l types.Leaf
+		if err := l.FromBinary(leaf.LeafValue); err != nil {
+			return nil, fmt.Errorf("unexpected leaf(%d): %v", leafIndex, err)
+		}
+		list = append(list[:], l)
+	}
+	return &list, nil
+}
+
+func treeHeadFromLogRoot(lr *trillianTypes.LogRootV1) *types.TreeHead {
+	th := types.TreeHead{
+		Timestamp: uint64(time.Now().Unix()),
+		TreeSize:  uint64(lr.TreeSize),
+	}
+	copy(th.RootHash[:], lr.RootHash)
+	return &th
+}
+
+func nodePathFromHashes(hashes [][]byte) ([]merkle.Hash, error) {
+	path := make([]merkle.Hash, len(hashes))
+	for i := 0; i < len(hashes); i++ {
+		if len(hashes[i]) != merkle.HashSize {
+			return nil, fmt.Errorf("unexpected hash length: %v", len(hashes[i]))
+		}
+
+		copy(path[i][:], hashes[i])
+	}
+	return path, nil
+}