table: add Best/MultiPath option to SelectOption

Signed-off-by: Wataru Ishida <ishida.wataru@lab.ntt.co.jp>

2 files changed, 51 insertions, 15 deletions

diff --git a/table/destination.go b/table/destination.go
index 3a1c1c45..845c2ab2 100644
--- a/table/destination.go
+++ b/table/destination.go
@@ -852,9 +852,11 @@ func (dest *Destination) String() string {
 }
 
 type DestinationSelectOption struct {
-	ID  string
-	VRF *Vrf
-	adj bool
+	ID        string
+	VRF       *Vrf
+	adj       bool
+	Best      bool
+	MultiPath bool
 }
 
 func (d *Destination) MarshalJSON() ([]byte, error) {
@@ -865,6 +867,8 @@ func (old *Destination) Select(option ...DestinationSelectOption) *Destination {
 	id := GLOBAL_RIB_NAME
 	var vrf *Vrf
 	adj := false
+	best := false
+	mp := false
 	for _, o := range option {
 		if o.ID != "" {
 			id = o.ID
@@ -873,27 +877,50 @@ func (old *Destination) Select(option ...DestinationSelectOption) *Destination {
 			vrf = o.VRF
 		}
 		adj = o.adj
+		best = o.Best
+		mp = o.MultiPath
 	}
 	var paths []*Path
 	if adj {
 		paths = old.knownPathList
 	} else {
 		paths = old.GetKnownPathList(id)
+		if vrf != nil {
+			ps := make([]*Path, 0, len(paths))
+			for _, p := range paths {
+				if CanImportToVrf(vrf, p) {
+					ps = append(ps, p)
+				}
+			}
+			paths = ps
+		}
+		if len(paths) == 0 {
+			return nil
+		}
+		if best {
+			if !mp {
+				paths = []*Path{paths[0]}
+			} else {
+				ps := make([]*Path, 0, len(paths))
+				var best *Path
+				for _, p := range paths {
+					if best == nil {
+						best = p
+						ps = append(ps, p)
+					} else if best.Compare(p) == 0 {
+						ps = append(ps, p)
+					}
+				}
+				paths = ps
+			}
+		}
 	}
 	new := NewDestination(old.nlri)
-	list := make([]*Path, 0, len(old.knownPathList))
 	for _, path := range paths {
-		if vrf != nil && !CanImportToVrf(vrf, path) {
-			continue
-		}
 		p := path.Clone(path.IsWithdraw)
 		p.Filter("", path.Filtered(id))
-		list = append(list, p)
-	}
-	if len(list) == 0 {
-		return nil
+		new.knownPathList = append(new.knownPathList, p)
 	}
-	new.knownPathList = list
 	return new
 }
 
diff --git a/table/table.go b/table/table.go
index f89e8dff..143c4c53 100644
--- a/table/table.go
+++ b/table/table.go
@@ -43,6 +43,8 @@ type TableSelectOption struct {
 	LookupPrefixes []*LookupPrefix
 	VRF            *Vrf
 	adj            bool
+	Best           bool
+	MultiPath      bool
 }
 
 type Table struct {
@@ -314,6 +316,8 @@ func (t *Table) Select(option ...TableSelectOption) (*Table, error) {
 	var vrf *Vrf
 	adj := false
 	prefixes := make([]*LookupPrefix, 0, len(option))
+	best := false
+	mp := false
 	for _, o := range option {
 		if o.ID != "" {
 			id = o.ID
@@ -323,12 +327,15 @@ func (t *Table) Select(option ...TableSelectOption) (*Table, error) {
 		}
 		adj = o.adj
 		prefixes = append(prefixes, o.LookupPrefixes...)
+		best = o.Best
+		mp = o.MultiPath
 	}
+	dOption := DestinationSelectOption{ID: id, VRF: vrf, adj: adj, Best: best, MultiPath: mp}
 	dsts := make(map[string]*Destination)
 	if (t.routeFamily == bgp.RF_IPv4_UC || t.routeFamily == bgp.RF_IPv6_UC) && len(prefixes) > 0 {
 		f := func(id, key string) (bool, error) {
 			if dst := t.GetDestination(key); dst != nil {
-				if d := dst.Select(DestinationSelectOption{ID: id, adj: adj}); d != nil {
+				if d := dst.Select(dOption); d != nil {
 					dsts[key] = d
 					return true, nil
 				}
@@ -344,7 +351,9 @@ func (t *Table) Select(option ...TableSelectOption) (*Table, error) {
 					return nil, err
 				}
 				for _, dst := range ds {
-					dsts[dst.GetNlri().String()] = dst.Select(DestinationSelectOption{ID: id, adj: adj})
+					if d := dst.Select(dOption); d != nil {
+						dsts[dst.GetNlri().String()] = d
+					}
 				}
 			case LOOKUP_SHORTER:
 				_, prefix, err := net.ParseCIDR(key)
@@ -374,7 +383,7 @@ func (t *Table) Select(option ...TableSelectOption) (*Table, error) {
 		}
 	} else {
 		for k, dst := range t.GetDestinations() {
-			if d := dst.Select(DestinationSelectOption{ID: id, VRF: vrf, adj: adj}); d != nil {
+			if d := dst.Select(dOption); d != nil {
 				dsts[k] = d
 			}
 		}