Improve resiliency on ip context policy routes

pkg/kernel/networkservice/connectioncontextkernel/ipcontext/iprule/heal.go

@@ -0,0 +1,96 @@
+// Copyright (c) 2022 Doc.ai and/or its affiliates.
+//
+// Copyright (c) 2021-2022 Nordix Foundation.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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.
+
+//go:build linux
+// +build linux
+
+package iprule
+
+import (
+	"context"
+
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+	"github.com/networkservicemesh/api/pkg/api/networkservice/mechanisms/kernel"
+	"github.com/networkservicemesh/sdk/pkg/tools/log"
+	"github.com/pkg/errors"
+	"github.com/vishvananda/netlink"
+
+	link "github.com/networkservicemesh/sdk-kernel/pkg/kernel"
+)
+
+func recoverTableIDs(ctx context.Context, conn *networkservice.Connection, tableIDs *Map) error {
+	if mechanism := kernel.ToMechanism(conn.GetMechanism()); mechanism != nil && mechanism.GetVLAN() == 0 {
+		_, ok := tableIDs.Load(conn.GetId())
+		if ok {
+			return nil
+		}
+
+		if len(conn.Context.IpContext.Policies) == 0 {
+			return nil
+		}
+
+		netlinkHandle, err := link.GetNetlinkHandle(mechanism.GetNetNSURL())
+		if err != nil {
+			return errors.WithStack(err)
+		}
+		defer netlinkHandle.Close()
+
+		podRules, err := netlinkHandle.RuleList(netlink.FAMILY_ALL)
+		if err != nil {
+			return errors.WithStack(err)
+		}
+
+		// try to find the corresponding missing policies in the network namespace of the pod
+		for _, policy := range conn.Context.IpContext.Policies {
+			policyRule, err := policyToRule(policy)
+			if err != nil {
+				return errors.WithStack(err)
+			}
+			for i := range podRules {
+				if ruleEquals(&podRules[i], policyRule) {
+					log.FromContext(ctx).
+						WithField("From", policy.From).
+						WithField("IPProto", policy.Proto).
+						WithField("DstPort", policy.DstPort).
+						WithField("SrcPort", policy.SrcPort).
+						WithField("Table", podRules[i].Table).Debug("policy recovered")
+					err := delRule(ctx, netlinkHandle, policy, podRules[i].Table)
+					if err != nil {
+						return errors.WithStack(err)
+					}
+					break
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func ruleEquals(a, b *netlink.Rule) bool {
+	if a == nil || b == nil {
+		return a == nil && b == nil
+	}
+	return a.Src.String() == b.Src.String() && a.IPProto == b.IPProto && rulePortRangeEquals(a.Dport, b.Dport) && rulePortRangeEquals(a.Sport, b.Sport)
+}
+
+func rulePortRangeEquals(a, b *netlink.RulePortRange) bool {
+	if a == nil || b == nil {
+		return a == nil && b == nil
+	}
+	return a.Start == b.Start && a.End == b.End
+}

pkg/kernel/networkservice/connectioncontextkernel/ipcontext/iprule/server.go

@@ -2,6 +2,8 @@
 //
 // Copyright (c) 2022 Doc.ai and/or its affiliates.
 //
+// Copyright (c) 2021-2022 Nordix Foundation.
+//
 // SPDX-License-Identifier: Apache-2.0
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -48,6 +50,11 @@ func (i *ipruleServer) Request(ctx context.Context, request *networkservice.Netw
 		return nil, err
 	}
 
+	err = recoverTableIDs(ctx, conn, &i.tables)
+	if err != nil {
+		return nil, err
+	}
+
 	if err := create(ctx, conn, &i.tables); err != nil {
 		closeCtx, cancelClose := postponeCtxFunc()
 		defer cancelClose()