fix: fix some nat traversal bugs

[YTGhost]

No description provided.

[codecov]

Codecov Report

Attention: 157 lines in your changes are missing coverage. Please review.

Comparison is base (bee0a5d) 40.89% compared to head (332eabf) 37.72%.
Report is 3 commits behind head on main.

Files	Patch %	Lines
pkg/networkengine/vpndriver/libreswan/libreswan.go	36.02%	106 Missing and 13 partials ⚠️
pkg/utils/stun.go	9.67%	28 Missing ⚠️
pkg/networkengine/vpndriver/driver.go	0.00%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #141      +/-   ##
==========================================
- Coverage   40.89%   37.72%   -3.18%     
==========================================
  Files           9       10       +1     
  Lines        1137     1275     +138     
==========================================
+ Hits          465      481      +16     
- Misses        582      697     +115     
- Partials       90       97       +7     

Flag	Coverage Δ
unittests	37.72% <30.83%> (-3.18%)	⬇️

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[YTGhost]

@BSWANG @njucjc @River-sh PTAL

[River-sh]

A switch should be provided in boot options to enable or disable nat traversal

[YTGhost]

A switch should be provided in boot options to enable or disable nat traversal

ok, I'll add this switch.