1 files changed, 159 insertions, 0 deletions
diff --git a/pkg/instance/instance.go b/pkg/instance/instance.go
new file mode 100644
index 0000000..c2fe8fa
--- /dev/null
+++ b/pkg/instance/instance.go
@@ -0,0 +1,159 @@
+package stfe
+
+import (
+	"context"
+	"crypto"
+	"crypto/ed25519"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/golang/glog"
+	"github.com/system-transparency/stfe/pkg/state"
+	"github.com/system-transparency/stfe/pkg/trillian"
+	"github.com/system-transparency/stfe/pkg/types"
+)
+
+// Config is a collection of log parameters
+type Config struct {
+	LogID    string        // H(public key), then hex-encoded
+	TreeID   int64         // Merkle tree identifier used by Trillian
+	Prefix   string        // The portion between base URL and st/v0 (may be "")
+	MaxRange int64         // Maximum number of leaves per get-leaves request
+	Deadline time.Duration // Deadline used for gRPC requests
+	Interval time.Duration // Cosigning frequency
+
+	// Witnesses map trusted witness identifiers to public verification keys
+	Witnesses map[[types.HashSize]byte][types.VerificationKeySize]byte
+}
+
+// Instance is an instance of the log's front-end
+type Instance struct {
+	Config                      // configuration parameters
+	Client   trillian.Client    // provides access to the Trillian backend
+	Signer   crypto.Signer      // provides access to Ed25519 private key
+	Stateman state.StateManager // coordinates access to (co)signed tree heads
+}
+
+// Handler implements the http.Handler interface, and contains a reference
+// to an STFE server instance as well as a function that uses it.
+type Handler struct {
+	Instance *Instance
+	Endpoint types.Endpoint
+	Method   string
+	Handler  func(context.Context, *Instance, http.ResponseWriter, *http.Request) (int, error)
+}
+
+// Handlers returns a list of STFE handlers
+func (i *Instance) Handlers() []Handler {
+	return []Handler{
+		Handler{Instance: i, Handler: addLeaf, Endpoint: types.EndpointAddLeaf, Method: http.MethodPost},
+		Handler{Instance: i, Handler: addCosignature, Endpoint: types.EndpointAddCosignature, Method: http.MethodPost},
+		Handler{Instance: i, Handler: getTreeHeadLatest, Endpoint: types.EndpointGetTreeHeadLatest, Method: http.MethodGet},
+		Handler{Instance: i, Handler: getTreeHeadToSign, Endpoint: types.EndpointGetTreeHeadToSign, Method: http.MethodGet},
+		Handler{Instance: i, Handler: getTreeHeadCosigned, Endpoint: types.EndpointGetTreeHeadCosigned, Method: http.MethodGet},
+		Handler{Instance: i, Handler: getConsistencyProof, Endpoint: types.EndpointGetConsistencyProof, Method: http.MethodPost},
+		Handler{Instance: i, Handler: getInclusionProof, Endpoint: types.EndpointGetProofByHash, Method: http.MethodPost},
+		Handler{Instance: i, Handler: getLeaves, Endpoint: types.EndpointGetLeaves, Method: http.MethodPost},
+	}
+}
+
+// Path returns a path that should be configured for this handler
+func (h Handler) Path() string {
+	return h.Endpoint.Path(h.Instance.Prefix, "st", "v0")
+}
+
+// ServeHTTP is part of the http.Handler interface
+func (a Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// export prometheus metrics
+	var now time.Time = time.Now()
+	var statusCode int
+	defer func() {
+		rspcnt.Inc(a.Instance.LogID, string(a.Endpoint), fmt.Sprintf("%d", statusCode))
+		latency.Observe(time.Now().Sub(now).Seconds(), a.Instance.LogID, string(a.Endpoint), fmt.Sprintf("%d", statusCode))
+	}()
+	reqcnt.Inc(a.Instance.LogID, string(a.Endpoint))
+
+	ctx, cancel := context.WithDeadline(r.Context(), now.Add(a.Instance.Deadline))
+	defer cancel()
+
+	if r.Method != a.Method {
+		glog.Warningf("%s/%s: got HTTP %s, wanted HTTP %s", a.Instance.Prefix, string(a.Endpoint), r.Method, a.Method)
+		http.Error(w, "", http.StatusMethodNotAllowed)
+		return
+	}
+
+	statusCode, err := a.Handler(ctx, a.Instance, w, r)
+	if err != nil {
+		glog.Warningf("handler error %s/%s: %v", a.Instance.Prefix, a.Endpoint, err)
+		http.Error(w, fmt.Sprintf("%s%s%s%s", "Error", types.Delim, err.Error(), types.EOL), statusCode)
+	}
+}
+
+func (i *Instance) leafRequestFromHTTP(r *http.Request) (*types.LeafRequest, error) {
+	var req types.LeafRequest
+	if err := req.UnmarshalASCII(r.Body); err != nil {
+		return nil, fmt.Errorf("UnmarshalASCII: %v", err)
+	}
+
+	vk := ed25519.PublicKey(req.VerificationKey[:])
+	msg := req.Message.Marshal()
+	sig := req.Signature[:]
+	if !ed25519.Verify(vk, msg, sig) {
+		return nil, fmt.Errorf("invalid signature")
+	}
+	// TODO: check shard hint
+	// TODO: check domain hint
+	return &req, nil
+}
+
+func (i *Instance) cosignatureRequestFromHTTP(r *http.Request) (*types.CosignatureRequest, error) {
+	var req types.CosignatureRequest
+	if err := req.UnmarshalASCII(r.Body); err != nil {
+		return nil, fmt.Errorf("unpackOctetPost: %v", err)
+	}
+	if _, ok := i.Witnesses[*req.KeyHash]; !ok {
+		return nil, fmt.Errorf("Unknown witness: %x", req.KeyHash)
+	}
+	return &req, nil
+}
+
+func (i *Instance) consistencyProofRequestFromHTTP(r *http.Request) (*types.ConsistencyProofRequest, error) {
+	var req types.ConsistencyProofRequest
+	if err := req.UnmarshalASCII(r.Body); err != nil {
+		return nil, fmt.Errorf("UnmarshalASCII: %v", err)
+	}
+	if req.OldSize < 1 {
+		return nil, fmt.Errorf("OldSize(%d) must be larger than zero", req.OldSize)
+	}
+	if req.NewSize <= req.OldSize {
+		return nil, fmt.Errorf("NewSize(%d) must be larger than OldSize(%d)", req.NewSize, req.OldSize)
+	}
+	return &req, nil
+}
+
+func (i *Instance) inclusionProofRequestFromHTTP(r *http.Request) (*types.InclusionProofRequest, error) {
+	var req types.InclusionProofRequest
+	if err := req.UnmarshalASCII(r.Body); err != nil {
+		return nil, fmt.Errorf("UnmarshalASCII: %v", err)
+	}
+	if req.TreeSize < 1 {
+		return nil, fmt.Errorf("TreeSize(%d) must be larger than zero", req.TreeSize)
+	}
+	return &req, nil
+}
+
+func (i *Instance) leavesRequestFromHTTP(r *http.Request) (*types.LeavesRequest, error) {
+	var req types.LeavesRequest
+	if err := req.UnmarshalASCII(r.Body); err != nil {
+		return nil, fmt.Errorf("UnmarshalASCII: %v", err)
+	}
+
+	if req.StartSize > req.EndSize {
+		return nil, fmt.Errorf("StartSize(%d) must be less than or equal to EndSize(%d)", req.StartSize, req.EndSize)
+	}
+	if req.EndSize-req.StartSize+1 > uint64(i.MaxRange) {
+		req.EndSize = req.StartSize + uint64(i.MaxRange) - 1
+	}
+	return &req, nil
+}