T6364: CGNAT drop hard limit that allows only one translation rule

[sever-sever]

Change Summary

As PoC for CGNAT had a hard limit in using only one translation rule for one internal pool,
Drop this limit and extend the usage number of the rules.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T6364

Related PR(s)

Component(s) name

cgnat

Proposed changes

How to test

And configuration with several translation rules (before it was possible only one rule):

set nat cgnat pool external ext-01 external-port-range '40000-60000'
set nat cgnat pool external ext-01 per-user-limit port '5000'
set nat cgnat pool external ext-01 range 192.0.2.1-192.0.2.2
set nat cgnat pool external ext-01 range 192.0.2.11/32

set nat cgnat pool external vyos-ext-02 external-port-range '2000-22000'
set nat cgnat pool external vyos-ext-02 per-user-limit port '2000'
set nat cgnat pool external vyos-ext-02 range 203.0.113.55/32

set nat cgnat pool internal int-01 range '100.64.0.0/29'
set nat cgnat pool internal vyos-int-02 range '100.64.222.10-100.64.222.12'

set nat cgnat rule 100 source pool 'int-01'
set nat cgnat rule 100 translation pool 'ext-01'
set nat cgnat rule 120 source pool 'vyos-int-02'
set nat cgnat rule 120 translation pool 'vyos-ext-02'

Check allocation to be sure that we see addresses in both pools:

vyos@r4# run show nat cgnat allocation 
Internal IP    External IP    Port range
-------------  -------------  ------------
100.64.0.0     192.0.2.1      40000-44999
100.64.0.1     192.0.2.1      45000-49999
100.64.0.2     192.0.2.1      50000-54999
100.64.0.3     192.0.2.1      55000-59999
100.64.0.4     192.0.2.2      40000-44999
100.64.0.5     192.0.2.2      45000-49999
100.64.0.6     192.0.2.2      50000-54999
100.64.0.7     192.0.2.2      55000-59999
100.64.222.10  203.0.113.55   2000-3999
100.64.222.11  203.0.113.55   4000-5999
100.64.222.12  203.0.113.55   6000-7999
[edit]
vyos@r4# 

Smoketest result

vyos@r4:~$ /usr/libexec/vyos/tests/smoke/cli/test_cgnat.py
test_cgnat (__main__.TestCGNAT.test_cgnat) ... ok

----------------------------------------------------------------------
Ran 1 test in 20.654s

OK
vyos@r4:~$ 

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly