decode/vlan: Extend VLAN encapsulation support to 3 levels.

[jlucovsky]

This is a draft PR; Git hygiene to applied to separate commits properly.

This PR extends Suricata's support for VLANs from 2 to 3 levels. There is no standard for 3 levels of VLANs but 3 levels are not uncommon in some environments.

Link to redmine ticket: 2816

Describe changes:

• Increase VLAN level support to 3 levels
• List all VLAN levels in output.
• Add "Q-in-Q-in-Q" unittest.

suricata-verify-pr: 902 #suricata-verify-repo: #suricata-verify-branch: #suricata-update-pr: #suricata-update-repo: #suricata-update-branch: #libhtp-pr: #libhtp-repo: #libhtp-branch:

[codecov[bot]]

Codecov Report

Merging #7700 (f159d32) into master (f3d3274) will increase coverage by 0.10%. The diff coverage is 89.65%.

@@            Coverage Diff             @@
##           master    #7700      +/-   ##
==========================================
+ Coverage   75.88%   75.98%   +0.10%     
==========================================
  Files         659      659              
  Lines      185668   185691      +23     
==========================================
+ Hits       140893   141099     +206     
+ Misses      44775    44592     -183     

Flag	Coverage Δ
fuzzcorpus	60.67% <82.92%> (+0.07%)	:arrow_up:
suricata-verify	52.56% <80.48%> (-0.03%)	:arrow_down:
unittests	60.72% <47.36%> (+0.01%)	:arrow_up:

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

[catenacyber]

See also https://github.com/OISF/suricata/pull/7384

[suricata-qa]

WARNING:

field	test	baseline	%
	generic_stats_chk
.capture.kernel_drops	5359243	5654519	94.78%
.flow.end.tcp_state.syn_sent	233	183	127.32%
.flow.end.tcp_state.syn_recv	63	52	121.15%
.tcp.segment_memcap_drop	29257	11729	249.44%
.tcp.insert_data_normal_fail	28863	11358	254.12%
.app_layer.error.http.parser	39	55	70.91%
.app_layer.error.smtp.gap	81	61	132.79%

Pipeline 8733 WARNING: THERE IS A KNOWN BAD BASELINE WITH PACKET DROPS. bE MINDFUL OF ANY RESULTS.

[jlucovsky]

Continued in #7784