feat(ct-metrics): BPF implementation

[SRodi]

Description

BPF implementation for connection tracking metrics. This is the data-plane work mentioned in this comment #1057 (comment)

Summary

• feature flag enableConntrackMetrics
• counters incremented within IFDEF in BPF
• counters: packets forward/reply + bytes forward/reply
• conntrack metadata includes metrics and is added to packets struct
• add/update unit tests for conntrack_linux and packetparser_linux

Related Issue

#806

Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• 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.

Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes made.

1. enableConntrackMetrics=false

   # bpftool map dump id 994 -j | jq -r .[0]
   {
     "key": [
       ...
     ],
     "value": [
       ...
     ],
     "formatted": {
       "key": {
         ...
       },
       "value": {
         ...
         "conntrack_metadata": {
           "bytes_forward_count": 0,
           "bytes_reply_count": 0,
           "packets_forward_count": 0,
           "packets_reply_count": 0
         }
       }
     }
   }

2. enableConntrackMetrics=true

   # bpftool map dump id 1019 -j | jq -r .[0]
   {
     "key": [
       ...
     ],
     "value": [
       ...
     ],
     "formatted": {
       "key": {
         ...
       },
       "value": {
         ...,
         "conntrack_metadata": {
           "bytes_forward_count": 13440,
           "bytes_reply_count": 56335,
           "packets_forward_count": 56,
           "packets_reply_count": 43
         }
       }
     }
   }

   At userland level I provisionally added a debug statement, just for this test, in packetparser_linux.go (without IP and proto translation)

   ❯ k logs -n kube-system retina-agent-chvdh | head -n 10 | grep metadata
   Defaulted container "retina" out of: retina, init-retina (init)
   ts=2024-12-13T10:37:08.881Z level=debug caller=packetparser/packetparser_linux.go:577 msg="Conntrack metadata" SrcIp=788657162 DstIp=2499867658 SrcPort=19117 DstPort=23313 Proto=6 PacketsForwardCount=73 PacketsReplyCount=83 BytesForwardCount=16068 BytesReplyCount=6936
   ts=2024-12-13T10:37:08.881Z level=debug caller=packetparser/packetparser_linux.go:577 msg="Conntrack metadata" SrcIp=788657162 DstIp=2499867658 SrcPort=19117 DstPort=23313 Proto=6 PacketsForwardCount=73 PacketsReplyCount=82 BytesForwardCount=16068 BytesReplyCount=6870

Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the CONTRIBUTING.md file for more information on how to contribute to this project.

Copilot reviewed 8 out of 10 changed files in this pull request and generated no suggestions.

Files not reviewed (2)

• pkg/plugin/conntrack/_cprog/conntrack.c: Language not supported
• pkg/plugin/packetparser/_cprog/packetparser.c: Language not supported

Copilot reviewed 8 out of 17 changed files in this pull request and generated no suggestions.

Files not reviewed (9)

• pkg/plugin/conntrack/_cprog/conntrack.c: Language not supported
• pkg/plugin/conntrack/_cprog/dynamic.h: Language not supported
• pkg/plugin/packetparser/_cprog/dynamic.h: Language not supported
• pkg/plugin/packetparser/_cprog/packetparser.c: Language not supported
• pkg/plugin/packetparser/packetparser_bpfel_x86.go: Evaluated as low risk
• pkg/plugin/packetparser/packetparser_linux.go: Evaluated as low risk
• pkg/config/config.go: Evaluated as low risk
• deploy/legacy/manifests/controller/helm/retina/templates/configmap.yaml: Evaluated as low risk
• deploy/hubble/manifests/controller/helm/retina/templates/agent/configmap.yaml: Evaluated as low risk

[vakalapa]

Overall looks good to me, punting to @nddq to review the conntrack pieces.

Copilot reviewed 7 out of 19 changed files in this pull request and generated no suggestions.

Files not reviewed (12)

• pkg/plugin/conntrack/_cprog/conntrack.c: Language not supported
• pkg/plugin/conntrack/_cprog/dynamic.h: Language not supported
• pkg/plugin/packetparser/_cprog/dynamic.h: Language not supported
• pkg/plugin/packetparser/_cprog/packetparser.c: Language not supported
• pkg/plugin/packetparser/packetparser_bpfel_arm64.go: Evaluated as low risk
• pkg/plugin/packetparser/packetparser_linux.go: Evaluated as low risk
• pkg/plugin/packetparser/packetparser_bpfel_x86.go: Evaluated as low risk
• pkg/config/config.go: Evaluated as low risk
• deploy/hubble/manifests/controller/helm/retina/templates/agent/configmap.yaml: Evaluated as low risk
• pkg/plugin/conntrack/conntrack_bpfel_x86.go: Evaluated as low risk
• deploy/legacy/manifests/controller/helm/retina/templates/configmap.yaml: Evaluated as low risk
• pkg/plugin/conntrack/conntrack_bpfel_arm64.go: Evaluated as low risk