1 files changed, 193 insertions, 0 deletions
diff --git a/pkg/db/trillian.go b/pkg/db/trillian.go
new file mode 100644
index 0000000..ab57db6
--- /dev/null
+++ b/pkg/db/trillian.go
@@ -0,0 +1,193 @@
+package db
+
+import (
+	"context"
+	"fmt"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/requests"
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+	"github.com/golang/glog"
+	"github.com/google/trillian"
+	trillianTypes "github.com/google/trillian/types"
+	"google.golang.org/grpc/codes"
+)
+
+// 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
+}
+
+func (c *TrillianClient) AddLeaf(ctx context.Context, req *requests.Leaf) error {
+	leaf := types.Leaf{
+		Statement: types.Statement{
+			ShardHint: req.ShardHint,
+			Checksum:  req.Checksum,
+		},
+		Signature: req.Signature,
+		KeyHash:   *types.HashFn(req.VerificationKey[:]),
+	}
+	serialized := leaf.ToBinary()
+
+	glog.V(3).Infof("queueing leaf request: %x", types.LeafHash(serialized))
+	rsp, err := c.GRPC.QueueLeaf(ctx, &trillian.QueueLeafRequest{
+		LogId: c.TreeID,
+		Leaf: &trillian.LogLeaf{
+			LeafValue: serialized,
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("backend failure: %v", err)
+	}
+	if rsp == nil {
+		return fmt.Errorf("no response")
+	}
+	if rsp.QueuedLeaf == nil {
+		return fmt.Errorf("no queued leaf")
+	}
+	if codes.Code(rsp.QueuedLeaf.GetStatus().GetCode()) == codes.AlreadyExists {
+		return fmt.Errorf("leaf is already queued or included")
+	}
+	return nil
+}
+
+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) != types.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(lr.TimestampNanos / 1000 / 1000 / 1000),
+		TreeSize:  uint64(lr.TreeSize),
+	}
+	copy(th.RootHash[:], lr.RootHash)
+	return &th
+}
+
+func nodePathFromHashes(hashes [][]byte) ([]types.Hash, error) {
+	path := make([]types.Hash, len(hashes))
+	for i := 0; i < len(hashes); i++ {
+		if len(hashes[i]) != types.HashSize {
+			return nil, fmt.Errorf("unexpected hash length: %v", len(hashes[i]))
+		}
+
+		copy(path[i][:], hashes[i])
+	}
+	return path, nil
+}