Fix: raven traffic ignore nat

[YTGhost]

Fixes #124

[codecov]

Codecov Report

Merging #131 (dc359e5) into main (5e8937d) will decrease coverage by 0.04%.
Report is 1 commits behind head on main.
The diff coverage is 30.00%.

@@            Coverage Diff             @@
##             main     #131      +/-   ##
==========================================
- Coverage   42.73%   42.69%   -0.04%     
==========================================
  Files           7        7              
  Lines        1053     1089      +36     
==========================================
+ Hits          450      465      +15     
- Misses        513      534      +21     
  Partials       90       90              

Flag	Coverage Δ
unittests	42.69% <30.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
pkg/networkengine/routedriver/vxlan/vxlan.go	57.94% <ø> (+2.53%)	⬆️
pkg/networkengine/vpndriver/libreswan/libreswan.go	45.71% <30.00%> (-3.62%)	⬇️

[YTGhost]

@njucjc PTAL

[njucjc]

LGTM

[YTGhost]

@BSWANG This pr still needs some modifications based on our last discussion.

[rambohe-ch]

@YTGhost It seems that unit tests is not enough, please fix it.