BS: Max MaxExpTime configurable (#2972)

This PR makes the MaxExpTime for segments configurable through the
policy.

fixes #2968

go/beacon_srv/BUILD.bazel

@@ -34,6 +34,7 @@ go_library(
         "//go/lib/snet:go_default_library",
         "//go/lib/sock/reliable:go_default_library",
         "//go/lib/sock/reliable/reconnect:go_default_library",
+        "//go/lib/spath:go_default_library",
         "//go/lib/topology:go_default_library",
         "//go/proto:go_default_library",
         "@com_github_burntsushi_toml//:go_default_library",

go/beacon_srv/internal/beacon/BUILD.bazel

@@ -20,6 +20,7 @@ go_library(
         "//go/lib/infra/modules/db:go_default_library",
         "//go/lib/log:go_default_library",
         "//go/lib/prom:go_default_library",
+        "//go/lib/spath:go_default_library",
         "//go/proto:go_default_library",
         "@com_github_opentracing_opentracing_go//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",

go/beacon_srv/internal/beacon/policy.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/scionproto/scion/go/lib/addr"
 	"github.com/scionproto/scion/go/lib/common"
+	"github.com/scionproto/scion/go/lib/spath"
 )
 
 // PolicyType is the policy type.
@@ -44,6 +45,8 @@ const (
 	DefaultCandidateSetSize = 100
 	// DefaultMaxHopsLength is the default MaxHopsLength value.
 	DefaultMaxHopsLength = 10
+	// DefaultMaxExpTime is the default MaxExpTime value.
+	DefaultMaxExpTime = spath.DefaultHopFExpiry
 )
 
 // Policies keeps track of all policies for a non-core beacon store.
@@ -178,6 +181,9 @@ type Policy struct {
 	// CandidateSetSize is the number of segments to consider for
 	// selection.
 	CandidateSetSize int `yaml:"CandidateSetSize"`
+	// MaxExpTime indicates the maximum value for the expiration time when
+	// extending the segment.
+	MaxExpTime *spath.ExpTimeType `yaml:"MaxExpTime"`
 	// Filter is the filter applied to segments.
 	Filter Filter `yaml:"Filter"`
 	// Type is the policy type.
@@ -192,14 +198,21 @@ func (p *Policy) InitDefaults() {
 	if p.CandidateSetSize == 0 {
 		p.CandidateSetSize = DefaultCandidateSetSize
 	}
+	if p.MaxExpTime == nil {
+		m := DefaultMaxExpTime
+		p.MaxExpTime = &m
+	}
 	p.Filter.InitDefaults()
 }
 
-func (p *Policy) initDefaults(t PolicyType) {
+func (p *Policy) initDefaults(t PolicyType) error {
 	p.InitDefaults()
-	if p.Type == "" {
-		p.Type = t
+	if p.Type != "" && p.Type != t {
+		return common.NewBasicError("Specified policy type does not match", nil,
+			"expected", t, "actual", p.Type)
 	}
+	p.Type = t
+	return nil
 }
 
 // ParseYaml parses the policy in yaml format and initializes the default values.
@@ -208,13 +221,8 @@ func ParseYaml(b common.RawBytes, t PolicyType) (*Policy, error) {
 	if err := yaml.Unmarshal(b, p); err != nil {
 		return nil, common.NewBasicError("Unable to parse policy", err)
 	}
-	p.InitDefaults()
-	if p.Type == "" {
-		p.Type = t
-	}
-	if p.Type != t {
-		return nil, common.NewBasicError("Specified policy type does not match", nil,
-			"expected", t, "actual", p.Type)
+	if err := p.initDefaults(t); err != nil {
+		return nil, err
 	}
 	return p, nil
 }

go/beacon_srv/internal/beacon/policy_test.go

@@ -40,6 +40,7 @@ func TestLoadFromYaml(t *testing.T) {
 		SoMsg("BestSetSize", p.BestSetSize, ShouldEqual, 6)
 		SoMsg("CandidateSetSize", p.CandidateSetSize, ShouldEqual, 20)
 		SoMsg("Type", p.Type, ShouldEqual, t)
+		SoMsg("MaxExpTime", *p.MaxExpTime, ShouldEqual, 42)
 		SoMsg("MaxHopsLength", p.Filter.MaxHopsLength, ShouldEqual, 8)
 		SoMsg("AsBlackList", p.Filter.AsBlackList, ShouldResemble, []addr.AS{ia110.A, ia111.A})
 		SoMsg("IsdBlackList", p.Filter.IsdBlackList, ShouldResemble, []addr.ISD{1, 2, 3})

go/beacon_srv/internal/beacon/store.go

@@ -23,6 +23,7 @@ import (
 	"github.com/scionproto/scion/go/lib/common"
 	"github.com/scionproto/scion/go/lib/ctrl/path_mgmt"
 	"github.com/scionproto/scion/go/lib/log"
+	"github.com/scionproto/scion/go/lib/spath"
 	"github.com/scionproto/scion/go/proto"
 )
 
@@ -72,10 +73,10 @@ func (s *Store) BeaconsToPropagate(ctx context.Context) (<-chan BeaconOrErr, err
 func (s *Store) SegmentsToRegister(ctx context.Context, segType proto.PathSegType) (
 	<-chan BeaconOrErr, error) {
 
-	switch {
-	case segType == proto.PathSegType_down:
+	switch segType {
+	case proto.PathSegType_down:
 		return s.getBeacons(ctx, &s.policies.DownReg)
-	case segType == proto.PathSegType_up:
+	case proto.PathSegType_up:
 		return s.getBeacons(ctx, &s.policies.UpReg)
 	default:
 		return nil, common.NewBasicError("Unsupported segment type", nil, "type", segType)
@@ -99,6 +100,19 @@ func (s *Store) getBeacons(ctx context.Context, policy *Policy) (<-chan BeaconOr
 	return results, nil
 }
 
+// MaxExpTime returns the segment maximum expiration time for the given policy.
+func (s *Store) MaxExpTime(policyType PolicyType) spath.ExpTimeType {
+	switch policyType {
+	case UpRegPolicy:
+		return *s.policies.UpReg.MaxExpTime
+	case DownRegPolicy:
+		return *s.policies.DownReg.MaxExpTime
+	case PropPolicy:
+		return *s.policies.Prop.MaxExpTime
+	}
+	return DefaultMaxExpTime
+}
+
 // CoreStore provides abstracted access to the beacon database in a core AS. The
 // store helps inserting beacons and revocations, and selects the best beacons
 // for given purposes based on the configured policies. It should not be used in
@@ -184,6 +198,17 @@ func (s *CoreStore) getBeacons(ctx context.Context, policy *Policy) (<-chan Beac
 	return results, nil
 }
 
+// MaxExpTime returns the segment maximum expiration time for the given policy.
+func (s *CoreStore) MaxExpTime(policyType PolicyType) spath.ExpTimeType {
+	switch policyType {
+	case CoreRegPolicy:
+		return *s.policies.CoreReg.MaxExpTime
+	case PropPolicy:
+		return *s.policies.Prop.MaxExpTime
+	}
+	return DefaultMaxExpTime
+}
+
 // baseStore is the basis for the beacon store.
 type baseStore struct {
 	db     DB

go/beacon_srv/internal/beacon/testdata/policy.yml

@@ -1,6 +1,7 @@
 ---
 BestSetSize: 6
 CandidateSetSize: 20
+MaxExpTime: 42
 Filter:
   MaxHopsLength: 8
   AsBlackList: ["ff00:0:110", "ff00:0:111"]

go/beacon_srv/internal/beacon/testdata/typedPolicy.yml

@@ -1,6 +1,7 @@
 ---
 BestSetSize: 6
 CandidateSetSize: 20
+MaxExpTime: 42
 Filter:
   MaxHopsLength: 8
   AsBlackList: ["ff00:0:110", "ff00:0:111"]

go/beacon_srv/internal/beaconing/extender.go

@@ -168,9 +168,7 @@ func (s *segExtender) createHopF(inIfid, egIfid common.IFIDType, prev common.Raw
 		return nil, common.NewBasicError("Chain does not cover minimum hop expiration time", nil,
 			"minimumExpiration", min, "chainExpiration", meta.ExpTime, "src", meta.Src)
 	}
-	if expiry > s.cfg.maxExpTime {
-		expiry = s.cfg.maxExpTime
-	}
+	expiry = min(expiry, s.cfg.GetMaxExpTime())
 	hop := &spath.HopField{
 		ConsIngress: inIfid,
 		ConsEgress:  egIfid,
@@ -191,3 +189,10 @@ func (s *segExtender) IntfActive(ifid common.IFIDType) bool {
 	intf := s.cfg.Intfs.Get(ifid)
 	return intf != nil && intf.State() == ifstate.Active
 }
+
+func min(a, b spath.ExpTimeType) spath.ExpTimeType {
+	if a > b {
+		return b
+	}
+	return a
+}

go/beacon_srv/internal/beaconing/extender_config.go

@@ -40,11 +40,8 @@ type ExtenderConf struct {
 	MTU uint16
 	// IfidSize is the bit-size of the ifid in the hop-fields.
 	IfidSize uint8
-	// MaxExpTime is the maximum relative expiration time.
-	MaxExpTime *spath.ExpTimeType
-	// maxExpTime is a copy of MaxExpTime to avoid using the captured
-	// reference from the calling code.
-	maxExpTime spath.ExpTimeType
+	// GetMaxExpTime returns the maximum relative expiration time.
+	GetMaxExpTime func() spath.ExpTimeType
 	// task contains an identifier specific to the task that uses the extender.
 	task string
 }
@@ -54,10 +51,6 @@ func (cfg *ExtenderConf) InitDefaults() {
 	if cfg.IfidSize == 0 {
 		cfg.IfidSize = DefaultIfidSize
 	}
-	if cfg.MaxExpTime == nil {
-		expiry := spath.DefaultHopFExpiry
-		cfg.MaxExpTime = &expiry
-	}
 }
 
 // Validate checks that the config contains a signer.
@@ -71,9 +64,5 @@ func (cfg *ExtenderConf) Validate() error {
 	if cfg.MTU == 0 {
 		return common.NewBasicError("MTU must be set", nil)
 	}
-	if cfg.MaxExpTime == nil {
-		return common.NewBasicError("MaxExpTime must be set", nil)
-	}
-	cfg.maxExpTime = *cfg.MaxExpTime
 	return nil
 }

go/beacon_srv/internal/beaconing/extender_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/golang/mock/gomock"
 	. "github.com/smartystreets/goconvey/convey"
 
+	"github.com/scionproto/scion/go/beacon_srv/internal/beacon"
 	"github.com/scionproto/scion/go/beacon_srv/internal/ifstate"
 	"github.com/scionproto/scion/go/lib/addr"
 	"github.com/scionproto/scion/go/lib/common"
@@ -116,10 +117,11 @@ func TestExtenderExtend(t *testing.T) {
 			intfs.Get(graph.If_111_A_112_X).Activate(graph.If_112_X_111_A)
 			intfs.Get(peer).Activate(graph.If_121_X_111_C)
 			ext, err := ExtenderConf{
-				MTU:    1337,
-				Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
-				Mac:    mac,
-				Intfs:  intfs,
+				MTU:           1337,
+				Signer:        testSigner(t, priv, topoProvider.Get().ISD_AS),
+				Mac:           mac,
+				Intfs:         intfs,
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			}.new()
 			SoMsg("err", err, ShouldBeNil)
 			// Create path segment from description, if available.
@@ -185,13 +187,12 @@ func TestExtenderExtend(t *testing.T) {
 		intfs := ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{})
 		xtest.FailOnErr(t, err)
 		intfs.Get(graph.If_111_B_120_X).Activate(graph.If_120_X_111_B)
-		var maxExpTime = spath.ExpTimeType(1)
 		ext, err := ExtenderConf{
-			MTU:        1337,
-			Signer:     testSigner(t, priv, topoProvider.Get().ISD_AS),
-			Mac:        mac,
-			MaxExpTime: &maxExpTime,
-			Intfs:      intfs,
+			MTU:           1337,
+			Signer:        testSigner(t, priv, topoProvider.Get().ISD_AS),
+			Mac:           mac,
+			GetMaxExpTime: maxExpTimeFactory(1),
+			Intfs:         intfs,
 		}.new()
 		SoMsg("err", err, ShouldBeNil)
 		pseg := testBeacon(g, segDesc).Segment
@@ -209,10 +210,11 @@ func TestExtenderExtend(t *testing.T) {
 		intfs := ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{})
 		xtest.FailOnErr(t, err)
 		ext, err := ExtenderConf{
-			MTU:    1337,
-			Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
-			Mac:    mac,
-			Intfs:  intfs,
+			MTU:           1337,
+			Signer:        testSigner(t, priv, topoProvider.Get().ISD_AS),
+			Mac:           mac,
+			Intfs:         intfs,
+			GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 		}.new()
 		SoMsg("err", err, ShouldBeNil)
 		pseg := testBeacon(g, segDesc).Segment
@@ -324,3 +326,9 @@ type failSigner struct {
 func (f *failSigner) Sign(msg common.RawBytes) (*proto.SignS, error) {
 	return nil, errors.New("fail")
 }
+
+func maxExpTimeFactory(max spath.ExpTimeType) func() spath.ExpTimeType {
+	return func() spath.ExpTimeType {
+		return max
+	}
+}

go/beacon_srv/internal/beaconing/originator_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/golang/mock/gomock"
 	. "github.com/smartystreets/goconvey/convey"
 
+	"github.com/scionproto/scion/go/beacon_srv/internal/beacon"
 	"github.com/scionproto/scion/go/beacon_srv/internal/ifstate"
 	"github.com/scionproto/scion/go/beacon_srv/internal/onehop"
 	"github.com/scionproto/scion/go/lib/addr"
@@ -59,10 +60,11 @@ func TestOriginatorRun(t *testing.T) {
 		conn := mock_snet.NewMockPacketConn(mctrl)
 		o, err := OriginatorConf{
 			Config: ExtenderConf{
-				MTU:    uint16(topoProvider.Get().MTU),
-				Signer: signer,
-				Intfs:  intfs,
-				Mac:    mac,
+				MTU:           uint16(topoProvider.Get().MTU),
+				Signer:        signer,
+				Intfs:         intfs,
+				Mac:           mac,
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			},
 			Period: time.Hour,
 			BeaconSender: &onehop.BeaconSender{
@@ -112,10 +114,11 @@ func TestOriginatorRun(t *testing.T) {
 		conn := mock_snet.NewMockPacketConn(mctrl)
 		o, err := OriginatorConf{
 			Config: ExtenderConf{
-				MTU:    uint16(topoProvider.Get().MTU),
-				Signer: signer,
-				Intfs:  intfs,
-				Mac:    mac,
+				MTU:           uint16(topoProvider.Get().MTU),
+				Signer:        signer,
+				Intfs:         intfs,
+				Mac:           mac,
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			},
 			Period: 2 * time.Second,
 			BeaconSender: &onehop.BeaconSender{

go/beacon_srv/internal/beaconing/propagator_test.go

@@ -148,8 +148,10 @@ func TestPropagatorRun(t *testing.T) {
 				Config: ExtenderConf{
 					Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
 					Mac:    macProp,
-					Intfs:  ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{}),
-					MTU:    uint16(topoProvider.Get().MTU),
+					Intfs: ifstate.NewInterfaces(topoProvider.Get().IFInfoMap,
+						ifstate.Config{}),
+					MTU:           uint16(topoProvider.Get().MTU),
+					GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 				},
 				Period:         time.Hour,
 				BeaconProvider: provider,
@@ -218,8 +220,10 @@ func TestPropagatorRun(t *testing.T) {
 			Config: ExtenderConf{
 				Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
 				Mac:    macProp,
-				Intfs:  ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{}),
-				MTU:    uint16(topoProvider.Get().MTU),
+				Intfs: ifstate.NewInterfaces(topoProvider.Get().IFInfoMap,
+					ifstate.Config{}),
+				MTU:           uint16(topoProvider.Get().MTU),
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			},
 			Period:         2 * time.Second,
 			BeaconProvider: provider,

go/beacon_srv/internal/beaconing/registrar_test.go

@@ -99,8 +99,10 @@ func TestRegistrarRun(t *testing.T) {
 				Config: ExtenderConf{
 					Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
 					Mac:    mac,
-					Intfs:  ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{}),
-					MTU:    uint16(topoProvider.Get().MTU),
+					Intfs: ifstate.NewInterfaces(topoProvider.Get().IFInfoMap,
+						ifstate.Config{}),
+					MTU:           uint16(topoProvider.Get().MTU),
+					GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 				},
 				Period:       time.Hour,
 				Msgr:         msgr,
@@ -190,8 +192,10 @@ func TestRegistrarRun(t *testing.T) {
 			Config: ExtenderConf{
 				Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
 				Mac:    mac,
-				Intfs:  ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{}),
-				MTU:    uint16(topoProvider.Get().MTU),
+				Intfs: ifstate.NewInterfaces(topoProvider.Get().IFInfoMap,
+					ifstate.Config{}),
+				MTU:           uint16(topoProvider.Get().MTU),
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			},
 			Msgr:         msgr,
 			SegProvider:  segProvider,
@@ -227,8 +231,10 @@ func TestRegistrarRun(t *testing.T) {
 			Config: ExtenderConf{
 				Signer: testSigner(t, priv, topoProvider.Get().ISD_AS),
 				Mac:    mac,
-				Intfs:  ifstate.NewInterfaces(topoProvider.Get().IFInfoMap, ifstate.Config{}),
-				MTU:    uint16(topoProvider.Get().MTU),
+				Intfs: ifstate.NewInterfaces(topoProvider.Get().IFInfoMap,
+					ifstate.Config{}),
+				MTU:           uint16(topoProvider.Get().MTU),
+				GetMaxExpTime: maxExpTimeFactory(beacon.DefaultMaxExpTime),
 			},
 			Msgr:         msgr,
 			SegProvider:  segProvider,