Update adjrib for LLGR and preserve aslooped attr

Fixes LLGR community cleared on softreset.
Fixes AS Path looped routes added back to rib on Graceful Restart.

3 files changed, 83 insertions, 3 deletions

diff --git a/internal/pkg/table/adj.go b/internal/pkg/table/adj.go
index 4b9d7c5f..d63537f8 100644
--- a/internal/pkg/table/adj.go
+++ b/internal/pkg/table/adj.go
@@ -173,11 +173,39 @@ func (adj *AdjRib) StaleAll(rfList []bgp.RouteFamily) []*Path {
 		for i, p := range d.knownPathList {
 			n := p.Clone(false)
 			n.MarkStale(true)
+			n.SetAsLooped(p.IsAsLooped())
 			d.knownPathList[i] = n
-			pathList = append(pathList, n)
+			if !n.IsAsLooped() {
+				pathList = append(pathList, n)
+			}
+		}
+		return false
+	})
+	return pathList
+}
+
+func (adj *AdjRib) MarkLLGRStaleOrDrop(rfList []bgp.RouteFamily) []*Path {
+	pathList := make([]*Path, 0, adj.Count(rfList))
+	adj.walk(rfList, func(d *Destination) bool {
+		for i, p := range d.knownPathList {
+			if p.HasNoLLGR() {
+				n := p.Clone(true)
+				n.SetDropped(true)
+				pathList = append(pathList, n)
+			} else {
+				n := p.Clone(false)
+				n.SetAsLooped(p.IsAsLooped())
+				n.SetCommunities([]uint32{uint32(bgp.COMMUNITY_LLGR_STALE)}, false)
+				if p.IsAsLooped() {
+					d.knownPathList[i] = n
+				} else {
+					pathList = append(pathList, n)
+				}
+			}
 		}
 		return false
 	})
+	adj.Update(pathList)
 	return pathList
 }
 
diff --git a/internal/pkg/table/adj_test.go b/internal/pkg/table/adj_test.go
index 8513bc97..9e48538f 100644
--- a/internal/pkg/table/adj_test.go
+++ b/internal/pkg/table/adj_test.go
@@ -69,14 +69,19 @@ func TestStale(t *testing.T) {
 	p1 := NewPath(pi, nlri1, false, attrs, time.Now(), false)
 	nlri2 := bgp.NewIPAddrPrefix(24, "20.20.20.0")
 	p2 := NewPath(pi, nlri2, false, attrs, time.Now(), false)
+	p2.SetAsLooped(true)
+
 	family := p1.GetRouteFamily()
 	families := []bgp.RouteFamily{family}
 
 	adj := NewAdjRib(families)
 	adj.Update([]*Path{p1, p2})
 	assert.Equal(t, adj.Count([]bgp.RouteFamily{family}), 2)
+	assert.Equal(t, adj.Accepted([]bgp.RouteFamily{family}), 1)
 
-	adj.StaleAll(families)
+	stalePathList := adj.StaleAll(families)
+	// As looped path should not be returned
+	assert.Equal(t, 1, len(stalePathList))
 
 	for _, p := range adj.PathList([]bgp.RouteFamily{family}, false) {
 		assert.True(t, p.IsStale())
@@ -86,7 +91,45 @@ func TestStale(t *testing.T) {
 	p3 := NewPath(pi, nlri3, false, attrs, time.Now(), false)
 	adj.Update([]*Path{p1, p3})
 
-	adj.DropStale(families)
+	droppedPathList := adj.DropStale(families)
+	assert.Equal(t, 2, len(droppedPathList))
 	assert.Equal(t, adj.Count([]bgp.RouteFamily{family}), 1)
 	assert.Equal(t, 1, len(adj.table[family].destinations))
 }
+
+func TestLLGRStale(t *testing.T) {
+	pi := &PeerInfo{}
+	attrs := []bgp.PathAttributeInterface{bgp.NewPathAttributeOrigin(0)}
+
+	nlri1 := bgp.NewIPAddrPrefix(24, "20.20.10.0")
+	p1 := NewPath(pi, nlri1, false, attrs, time.Now(), false)
+
+	nlri2 := bgp.NewIPAddrPrefix(24, "20.20.20.0")
+	p2 := NewPath(pi, nlri2, false, attrs, time.Now(), false)
+	p2.SetAsLooped(true) // Not accepted
+
+	nlri3 := bgp.NewIPAddrPrefix(24, "20.20.30.0")
+	p3 := NewPath(pi, nlri3, false, attrs, time.Now(), false)
+	p3.SetAsLooped(true)
+	// Not accepted and then dropped on MarkLLGRStaleOrDrop
+	p3.SetCommunities([]uint32{uint32(bgp.COMMUNITY_NO_LLGR)}, false)
+
+	nlri4 := bgp.NewIPAddrPrefix(24, "20.20.40.0")
+	p4 := NewPath(pi, nlri4, false, attrs, time.Now(), false)
+	// dropped on MarkLLGRStaleOrDrop
+	p4.SetCommunities([]uint32{uint32(bgp.COMMUNITY_NO_LLGR)}, false)
+
+	family := p1.GetRouteFamily()
+	families := []bgp.RouteFamily{family}
+
+	adj := NewAdjRib(families)
+	adj.Update([]*Path{p1, p2, p3, p4})
+	assert.Equal(t, adj.Count([]bgp.RouteFamily{family}), 4)
+	assert.Equal(t, adj.Accepted([]bgp.RouteFamily{family}), 2)
+
+	pathList := adj.MarkLLGRStaleOrDrop(families)
+	assert.Equal(t, 3, len(pathList)) // Does not return aslooped path that is retained in adjrib
+	assert.Equal(t, adj.Count([]bgp.RouteFamily{family}), 2)
+	assert.Equal(t, adj.Accepted([]bgp.RouteFamily{family}), 1)
+	assert.Equal(t, 2, len(adj.table[family].destinations))
+}
diff --git a/internal/pkg/table/path.go b/internal/pkg/table/path.go
index 32616d2e..9f68fde3 100644
--- a/internal/pkg/table/path.go
+++ b/internal/pkg/table/path.go
@@ -398,6 +398,15 @@ func (path *Path) SetDropped(y bool) {
 	path.dropped = y
 }
 
+func (path *Path) HasNoLLGR() bool {
+	for _, c := range path.GetCommunities() {
+		if c == uint32(bgp.COMMUNITY_NO_LLGR) {
+			return true
+		}
+	}
+	return false
+}
+
 func (path *Path) IsLLGRStale() bool {
 	for _, c := range path.GetCommunities() {
 		if c == uint32(bgp.COMMUNITY_LLGR_STALE) {