feat: add Windows drop reasons (#406)

# Description

Please provide a brief description of the changes made in this pull
request.

Add drop reasons specifically to windows builds.

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- [ ] I have correctly attributed the author(s) of the code.
- [ ] I have tested the changes locally.
- [ ] I have followed the project's style guidelines.
- [ ] I have updated the documentation, if necessary.
- [ ] I have added tests, if applicable.

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## Additional Notes

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---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
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pkg/utils/flow_utils.go

@@ -271,16 +271,8 @@ func AddDropReason(f *flow.Flow, meta *RetinaMetadata, dropReason uint32) {
  // Retina drop reasons are different from the drop reasons available in flow library.
  // We map the ones available in flow library to the ones available in Retina.
  // Rest are set to UNKNOWN. The details are added in the metadata.
- switch meta.GetDropReason() { //nolint:exhaustive // We are handling all the cases.
- case DropReason_IPTABLE_RULE_DROP:
- f.DropReasonDesc = flow.DropReason_POLICY_DENIED
- case DropReason_IPTABLE_NAT_DROP:
- f.DropReasonDesc = flow.DropReason_SNAT_NO_MAP_FOUND
- case DropReason_CONNTRACK_ADD_DROP:
- f.DropReasonDesc = flow.DropReason_UNKNOWN_CONNECTION_TRACKING_STATE
- default:
- f.DropReasonDesc = flow.DropReason_DROP_REASON_UNKNOWN
- }
+
+ f.DropReasonDesc = GetDropReasonDesc(meta.GetDropReason())
 
  f.EventType = &flow.CiliumEventType{
  Type: int32(api.MessageTypeDrop),

pkg/utils/utils_linux.go

@@ -10,6 +10,7 @@ import (
  "syscall"
  "unsafe"
 
+ "github.com/cilium/cilium/api/v1/flow"
  "github.com/pkg/errors"
  "github.com/vishvananda/netlink"
  "golang.org/x/exp/maps"
@@ -113,3 +114,20 @@ func isDefaultRoute(route netlink.Route) bool {
 
  return false
 }
+
+func GetDropReasonDesc(dr DropReason) flow.DropReason {
+ // Set the drop reason.
+ // Retina drop reasons are different from the drop reasons available in flow library.
+ // We map the ones available in flow library to the ones available in Retina.
+ // Rest are set to UNKNOWN. The details are added in the metadata.
+ switch dr { //nolint:exhaustive // We are handling all the cases.
+ case DropReason_IPTABLE_RULE_DROP:
+ return flow.DropReason_POLICY_DENIED
+ case DropReason_IPTABLE_NAT_DROP:
+ return flow.DropReason_SNAT_NO_MAP_FOUND
+ case DropReason_CONNTRACK_ADD_DROP:
+ return flow.DropReason_UNKNOWN_CONNECTION_TRACKING_STATE
+ default:
+ return flow.DropReason_DROP_REASON_UNKNOWN
+ }
+}

pkg/utils/utils_windows.go

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+package utils
+
+import (
+ "github.com/cilium/cilium/api/v1/flow"
+)
+
+func GetDropReasonDesc(dr DropReason) flow.DropReason {
+ switch dr { //nolint:exhaustive // We are handling all the cases.
+ case DropReason_Drop_INET_FinWait2:
+ return flow.DropReason_UNKNOWN_CONNECTION_TRACKING_STATE
+ default:
+ return flow.DropReason_DROP_REASON_UNKNOWN
+ }
+}