[TCP] Implementing TCP datapath

[SHiftLin]

Why are these changes needed?

Related issue number

Checks

• [ ] I've run scripts/clippy.sh to lint the changes in this PR.
• [ ] I've included any doc changes.
• Testing Strategy
  • [ ] Release tests
  • [ ] This PR is not tested :(

[crazyboycjr]

LGTM. Thanks!