TrustStore: Implement crypto provider

The crypto provider handles crypto material requests. If the
requested crypto material is in the database, it is returned.
Otherwise, the crypto provider decides based on the recurser
whether it can issue a network request. If it is allowed to,
it selects the path and remote using the router and calls
resolver to resolve all the missing material.

This PR is the start of a series of PRs that make the new trust store
operational. The individual components are then glued together into
the trust store. To the client package, the trust store appears as
a single unit.

Contributes to scionproto#3115

go/lib/infra/modules/trust/v2/BUILD.bazel

@@ -23,18 +23,35 @@ go_library(
         "//go/lib/scrypto:go_default_library",
         "//go/lib/scrypto/trc/v2:go_default_library",
         "//go/lib/serrors:go_default_library",
+        "@org_golang_x_xerrors//:go_default_library",
     ],
 )
 
 go_test(
     name = "go_default_test",
-    srcs = ["main_test.go"],
+    srcs = [
+        "export_test.go",
+        "main_test.go",
+        "provider_test.go",
+    ],
     data = [
         "//go/lib/infra/modules/trust/v2/testdata:crypto_tar",
     ],
     embed = [":go_default_library"],
     deps = [
+        "//go/lib/addr:go_default_library",
+        "//go/lib/infra:go_default_library",
+        "//go/lib/infra/modules/trust/v2/internal/decoded:go_default_library",
+        "//go/lib/infra/modules/trust/v2/mock_v2:go_default_library",
         "//go/lib/log:go_default_library",
+        "//go/lib/scrypto:go_default_library",
+        "//go/lib/scrypto/trc/v2:go_default_library",
+        "//go/lib/serrors:go_default_library",
+        "//go/lib/util:go_default_library",
         "//go/lib/xtest:go_default_library",
+        "@com_github_golang_mock//gomock:go_default_library",
+        "@com_github_stretchr_testify//assert:go_default_library",
+        "@com_github_stretchr_testify//require:go_default_library",
+        "@org_golang_x_xerrors//:go_default_library",
     ],
 )

go/lib/infra/modules/trust/v2/export_test.go

@@ -0,0 +1,30 @@
+// Copyright 2019 Anapaya Systems
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trust
+
+var NewCryptoProvider = newTestCryptoProvider
+
+// newTestCryptoProvider returns a new crypto provider for testing.
+func newTestCryptoProvider(db DBRead, recurser Recurser, resolver Resolver, router Router,
+	alwaysCacheOnly bool) CryptoProvider {
+
+	return &cryptoProvider{
+		db:              db,
+		recurser:        recurser,
+		resolver:        resolver,
+		router:          router,
+		alwaysCacheOnly: alwaysCacheOnly,
+	}
+}

go/lib/infra/modules/trust/v2/internal/decoded/BUILD.bazel

@@ -8,5 +8,6 @@ go_library(
     deps = [
         "//go/lib/scrypto/cert/v2:go_default_library",
         "//go/lib/scrypto/trc/v2:go_default_library",
+        "//go/lib/serrors:go_default_library",
     ],
 )

go/lib/infra/modules/trust/v2/internal/decoded/decode.go

@@ -19,15 +19,37 @@ import (
 
 	"github.com/scionproto/scion/go/lib/scrypto/cert/v2"
 	"github.com/scionproto/scion/go/lib/scrypto/trc/v2"
+	"github.com/scionproto/scion/go/lib/serrors"
 )
 
+// ErrParse indicates that parsign failed.
+var ErrParse = serrors.New("parse error")
+
 // TRC is a container for the decoded TRC.
 type TRC struct {
 	TRC    *trc.TRC
 	Signed trc.Signed
 	Raw    []byte
 }
 
+// DecodeTRC decodes the TRC.
+func DecodeTRC(raw []byte) (TRC, error) {
+	signed, err := trc.ParseSigned(raw)
+	if err != nil {
+		return TRC{}, serrors.WithCtx(ErrParse, err, "part", "signed")
+	}
+	decoded, err := signed.EncodedTRC.Decode()
+	if err != nil {
+		return TRC{}, serrors.WithCtx(ErrParse, err, "part", "decode payload")
+	}
+	d := TRC{
+		TRC:    decoded,
+		Signed: signed,
+		Raw:    raw,
+	}
+	return d, nil
+}
+
 func (d TRC) String() string {
 	if d.TRC == nil {
 		return "<nil>"

go/lib/infra/modules/trust/v2/main_test.go

@@ -16,17 +16,53 @@ package trust_test
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
+	"github.com/scionproto/scion/go/lib/addr"
+	"github.com/scionproto/scion/go/lib/infra/modules/trust/v2/internal/decoded"
 	"github.com/scionproto/scion/go/lib/log"
+	"github.com/scionproto/scion/go/lib/scrypto"
+	"github.com/scionproto/scion/go/lib/scrypto/trc/v2"
 	"github.com/scionproto/scion/go/lib/xtest"
 )
 
 // tmpDir contains the generated crypto material.
 var tmpDir string
 
+type TRCDesc struct {
+	ISD     addr.ISD
+	Version scrypto.Version
+}
+
+func (desc TRCDesc) File() string {
+	return fmt.Sprintf("ISD%d/trcs/ISD%d-V%d.trc", desc.ISD, desc.ISD, desc.Version)
+}
+
+var (
+	trc1v1 = TRCDesc{ISD: 1, Version: 1}
+
+	// primary ASes
+	ia110 = xtest.MustParseIA("1-ff00:0:110")
+	ia120 = xtest.MustParseIA("1-ff00:0:120")
+	ia130 = xtest.MustParseIA("1-ff00:0:130")
+)
+
+var (
+	trc2v1 = TRCDesc{ISD: 2, Version: 1}
+
+	// primary ASes
+	ia210 = xtest.MustParseIA("2-ff00:0:210")
+
+	// non-primary ASes
+	ia122 = xtest.MustParseIA("1-ff00:0:122")
+)
+
 func TestMain(m *testing.M) {
 	var cleanF func()
 	tmpDir, cleanF = xtest.MustTempDir("", "test-trust")
@@ -41,3 +77,19 @@ func TestMain(m *testing.M) {
 	log.Root().SetHandler(log.DiscardHandler())
 	os.Exit(m.Run())
 }
+
+func loadTRC(t *testing.T, desc TRCDesc) decoded.TRC {
+	t.Helper()
+	file := filepath.Join(tmpDir, desc.File())
+	raw, err := ioutil.ReadFile(file)
+	require.NoError(t, err)
+	signed, err := trc.ParseSigned(raw)
+	require.NoError(t, err)
+	trcObj, err := signed.EncodedTRC.Decode()
+	require.NoError(t, err)
+	return decoded.TRC{
+		Raw:    raw,
+		Signed: signed,
+		TRC:    trcObj,
+	}
+}

go/lib/infra/modules/trust/v2/mock_v2/BUILD.bazel

@@ -0,0 +1,16 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["v2.go"],
+    importpath = "github.com/scionproto/scion/go/lib/infra/modules/trust/v2/mock_v2",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//go/lib/addr:go_default_library",
+        "//go/lib/infra/modules/trust/v2:go_default_library",
+        "//go/lib/infra/modules/trust/v2/internal/decoded:go_default_library",
+        "//go/lib/scrypto:go_default_library",
+        "//go/lib/scrypto/trc/v2:go_default_library",
+        "@com_github_golang_mock//gomock:go_default_library",
+    ],
+)