Add SYSTEM_DEFAULTS['decap_qos_map'] to control IPInIP decap_dscp_to_tc_map

[markx-arista]

Why I did it

Currently ipinip.json.j2 is having platform checks for enabling/disabling decap entries. We want to prevent having platform checks for simple enable/disable scenarios.

Work item tracking

• Microsoft ADO (number only):

How I did it

Use SYSTEM_DEFAULTS['decap_qos_map']['status'] to control decap_dscp_to_tc_map instead of hardcoded ASIC vendor and hwsku checks. The decap_qos_map default is set in init_cfg.json.j2 (disabled for broadcom, enabled for others) and can be overridden per-SKU via golden config.

How to verify it

decap_qos_remap is set to disabled for Broadcom platforms, and enabled for others.

Which release branch to backport (provide reason below if selected)

• 202305
• 202311
• 202405
• 202411
• 202505
• 202511
• 202512
• 202605
• 202608

Tracking issue/work item for backport/cherry-pick request (GitHub issue or Microsoft ADO):
Failure type:

Tested branch

• master
• 202305
• 202311
• 202405
• 202411
• 202505
• 202511
• 202512
• 202605
• 202608
• N/A

Test result

With decap_qos_map disabled, decap_dscp_to_tc_map is not set:

admin@qspf201:~$ sonic-cfggen -d -v "SYSTEM_DEFAULTS"
{'decap_qos_map': {'status': 'disabled'}, 'mux_tunnel_egress_acl': {'status': 'disabled'}}

admin@qspf201:~$ sonic-db-cli APPL_DB HGETALL "TUNNEL_DECAP_TABLE:IPINIP_TUNNEL"
{'dscp_mode': 'pipe', 'ecn_mode': 'copy_from_outer', 'ttl_mode': 'pipe', 'tunnel_type': 'IPINIP'}

admin@qspf201:~$ sonic-db-cli APPL_DB HGETALL "TUNNEL_DECAP_TABLE:IPINIP_V6_TUNNEL"
{'dscp_mode': 'pipe', 'ecn_mode': 'copy_from_outer', 'ttl_mode': 'pipe', 'tunnel_type': 'IPINIP'}

With golden config enabling decap_qos_map:

admin@qspf201:~$ sonic-cfggen -d -v "SYSTEM_DEFAULTS"
{'decap_qos_map': {'status': 'enabled'}, 'mux_tunnel_egress_acl': {'status': 'disabled'}}

admin@qspf201:~$ sonic-db-cli APPL_DB HGETALL "TUNNEL_DECAP_TABLE:IPINIP_TUNNEL"
{'decap_dscp_to_tc_map': 'AZURE', 'dscp_mode': 'uniform', 'ecn_mode': 'copy_from_outer', 'ttl_mode': 'pipe', 'tunnel_type': 'IPINIP'}

admin@qspf201:~$ sonic-db-cli APPL_DB HGETALL "TUNNEL_DECAP_TABLE:IPINIP_V6_TUNNEL"
{'decap_dscp_to_tc_map': 'AZURE', 'dscp_mode': 'uniform', 'ecn_mode': 'copy_from_outer', 'ttl_mode': 'pipe', 'tunnel_type': 'IPINIP'}

Description for the changelog

Use SYSTEM_DEFAULTS['decap_qos_map']['status'] to control decap_dscp_to_tc_map

Link to config_db schema for YANG module changes

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[mssonicbld]

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[mssonicbld]

This PR has backport request for branch(es): 202511,202605.
Added label(s) for branch(es) 202511,202605.

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[mssonicbld]

This PR has backport request label(s) for branch(es): 202511,202605, but is missing required test information. Please make sure you tick the tested branch(es) in the Tested branch section and provide test evidence (e.g., 202511: <test result>) in the Test result section as well in your PR description.

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