Propage Pre/Post policy indicator from BMP Reciver into BGPPath

Signed-off-by: Maximilian Wilhelm <maximilian@cloudflare.com>

Author: Maximilian Wilhelm

protocols/bgp/server/fsm_address_family.go

@@ -165,7 +165,7 @@ func (f *fsmAddressFamily) processUpdate(u *packet.BGPUpdate, bmpPostPolicy bool
 		return
 	}
 
-	f.multiProtocolUpdates(u)
+	f.multiProtocolUpdates(u, bmpPostPolicy)
 	if f.afi == packet.AFIIPv4 {
 		f.withdraws(u, bmpPostPolicy)
 		f.updates(u, bmpPostPolicy)
@@ -175,24 +175,25 @@ func (f *fsmAddressFamily) processUpdate(u *packet.BGPUpdate, bmpPostPolicy bool
 func (f *fsmAddressFamily) withdraws(u *packet.BGPUpdate, bmpPostPolicy bool) {
 	for r := u.WithdrawnRoutes; r != nil; r = r.Next {
 		f.adjRIBIn.RemovePath(r.Prefix, &route.Path{
-			BMPPostPolicy: bmpPostPolicy,
+			BGPPath: &route.BGPPath{
+				BMPPostPolicy: bmpPostPolicy,
+			},
 		})
 	}
 }
 
 func (f *fsmAddressFamily) updates(u *packet.BGPUpdate, bmpPostPolicy bool) {
 	for r := u.NLRI; r != nil; r = r.Next {
-		path := f.newRoutePath()
-		path.BMPPostPolicy = bmpPostPolicy
+		path := f.newRoutePath(bmpPostPolicy)
 		f.processAttributes(u.PathAttributes, path)
 		path.BGPPath.PathIdentifier = u.NLRI.PathIdentifier
 
 		f.adjRIBIn.AddPath(r.Prefix, path)
 	}
 }
 
-func (f *fsmAddressFamily) multiProtocolUpdates(u *packet.BGPUpdate) {
-	path := f.newRoutePath()
+func (f *fsmAddressFamily) multiProtocolUpdates(u *packet.BGPUpdate, bmpPostPolicy bool) {
+	path := f.newRoutePath(bmpPostPolicy)
 	f.processAttributes(u.PathAttributes, path)
 
 	for pa := u.PathAttributes; pa != nil; pa = pa.Next {
@@ -205,10 +206,11 @@ func (f *fsmAddressFamily) multiProtocolUpdates(u *packet.BGPUpdate) {
 	}
 }
 
-func (f *fsmAddressFamily) newRoutePath() *route.Path {
+func (f *fsmAddressFamily) newRoutePath(bmpPostPolicy bool) *route.Path {
 	return &route.Path{
 		Type: route.BGPPathType,
 		BGPPath: &route.BGPPath{
+			BMPPostPolicy: bmpPostPolicy,
 			BGPPathA: &route.BGPPathA{
 				Source: f.fsm.peer.addr,
 				EBGP:   f.fsm.peer.localASN != f.fsm.peer.peerASN,

route/api/route.pb.go

@@ -49,6 +49,7 @@ message BGPPath {
     uint32 originator_id = 12;
     repeated uint32 cluster_list = 13;
     repeated UnknownPathAttribute unknown_attributes = 14;
+    bool bmp_post_policy = 15;
 }
 
 message ASPathSegment {

route/api/route.proto

@@ -22,6 +22,7 @@ type BGPPath struct {
 	UnknownAttributes []types.UnknownPathAttribute
 	PathIdentifier    uint32
 	ASPathLen         uint16
+	BMPPostPolicy     bool // BMPPostPolicy fields is a hack used in BMP to differentiate between pre/post policy routes (L flag of the per peer header)
 }
 
 // BGPPathA represents cachable BGP path attributes
@@ -73,6 +74,7 @@ func (b *BGPPath) ToProto() *api.BGPPath {
 		Source:            b.BGPPathA.Source.ToProto(),
 		UnknownAttributes: make([]*api.UnknownPathAttribute, len(b.UnknownAttributes)),
 		OriginatorId:      b.BGPPathA.OriginatorID,
+		BmpPostPolicy:     b.BMPPostPolicy,
 	}
 
 	if b.ASPath != nil {
@@ -122,6 +124,7 @@ func BGPPathFromProtoBGPPath(pb *api.BGPPath, dedup bool) *BGPPath {
 		},
 		PathIdentifier: pb.PathIdentifier,
 		ASPath:         types.ASPathFromProtoASPath(pb.AsPath),
+		BMPPostPolicy:  pb.BmpPostPolicy,
 	}
 
 	if dedup {

route/bgp_path.go

@@ -20,12 +20,11 @@ const (
 
 // Path represents a network path
 type Path struct {
-	Type          uint8
-	BMPPostPolicy bool  // BMPPostPolicy fields is a hack used in BMP to differentiate between pre/post policy routes (L flag of the per peer header)
-	HiddenReason  uint8 // If set, Path is hidden and ineligible to be installed in LocRIB and used for path selection
-	StaticPath    *StaticPath
-	BGPPath       *BGPPath
-	FIBPath       *FIBPath
+	Type         uint8
+	HiddenReason uint8 // If set, Path is hidden and ineligible to be installed in LocRIB and used for path selection
+	StaticPath   *StaticPath
+	BGPPath      *BGPPath
+	FIBPath      *FIBPath
 }
 
 // Select returns negative if p < q, 0 if paths are equal, positive if p > q