Default IPv6 route ::/0 not support in dash pipeline

[jimmyzhai]

Currently p4 PI does not support LPM match with prefix length 0.
https://github.com/p4lang/PI/blob/24e0a3c08c964e36d235973556b90e0ae922b894/proto/frontend/src/device_mgr.cpp#L2242-L2246

During kvm dpu starts up, swss orchagent creates default IPv6 route ::/0, then fails.

Related logs in sonic kvm dpu:

2025 Jan 10 09:25:15.733134 vlab-01 WARNING syncd#syncd_dash: w:- table_route_entry_add_keys: Invalid reprsentation of 'don't care' LPM match, omit match field instead of using a prefix length of 0
2025 Jan 10 09:25:15.733134 vlab-01 NOTICE syncd#syncd_dash: n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_USER_TRAP_ID with default value
2025 Jan 10 09:25:15.733134 vlab-01 NOTICE syncd#syncd_dash: n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_NEXT_HOP_ID with default value
2025 Jan 10 09:25:15.733134 vlab-01 NOTICE syncd#syncd_dash: n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_META_DATA with default value
2025 Jan 10 09:25:15.733134 vlab-01 NOTICE syncd#syncd_dash: n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_COUNTER_ID with default value
2025 Jan 10 09:25:15.733149 vlab-01 NOTICE syncd#syncd_dash: n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_PREFIX_AGG_ID with default value
2025 Jan 10 09:25:15.733221 vlab-01 INFO syncd#supervisord: syncd w:- table_route_entry_add_keys: Invalid reprsentation of 'don't care' LPM match, omit match field instead of using a prefix length of 0
2025 Jan 10 09:25:15.733221 vlab-01 INFO syncd#supervisord: syncd n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_USER_TRAP_ID with default value
2025 Jan 10 09:25:15.733221 vlab-01 INFO syncd#supervisord: syncd n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_NEXT_HOP_ID with default value
2025 Jan 10 09:25:15.733221 vlab-01 INFO syncd#supervisord: syncd n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_META_DATA with default value
2025 Jan 10 09:25:15.733221 vlab-01 INFO syncd#supervisord: syncd n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_COUNTER_ID with default value
2025 Jan 10 09:25:15.733340 vlab-01 INFO syncd#supervisord: syncd
2025 Jan 10 09:25:15.733340 vlab-01 INFO syncd#supervisord: syncd n:- populateDefaultAttributes: adding SAI_ROUTE_ENTRY_ATTR_PREFIX_AGG_ID with default value
2025 Jan 10 09:25:15.734898 vlab-01 ERR syncd#syncd_dash: e:- mutateTableEntry: GRPC ERROR[2]: , #010#002#032L#012#037type.googleapis.com/p4.v1.Error#022)#010#003#022#022Invalid match type#032#021ALL-sswitch-p4org
2025 Jan 10 09:25:15.734898 vlab-01 ERR syncd#syncd_dash: e:- mutateTableEntry: GRPC call Write::INSERT ERROR: table_id: 49279256 match { field_id: 1 } action { action { action_id: 32404057 params { param_id: 1 value: "\000\000" } params { param_id: 2 value: "\000\000" } } }
2025 Jan 10 09:25:15.734898 vlab-01 INFO syncd#supervisord: syncd e:- mutateTableEntry: GRPC ERROR[2]: , #010#002#032L
2025 Jan 10 09:25:15.734898 vlab-01 ERR syncd#syncd_dash: :- sendApiResponse: api SAI_COMMON_API_CREATE failed in syncd mode: SAI_STATUS_FAILURE
2025 Jan 10 09:25:15.734898 vlab-01 INFO syncd#supervisord: syncd #037type.googleapis.com/p4.v1.Error#022)#010#003#022#022Invalid match type#032#021ALL-sswitch-p4org
2025 Jan 10 09:25:15.734898 vlab-01 INFO syncd#supervisord: syncd e:- mutateTableEntry: GRPC call Write::INSERT ERROR: table_id: 49279256 match { field_id: 1 } action { action { action_id: 32404057 params { param_id: 1 value: "\000\000" } params { param_id: 2 value: "\000\000" } } }
2025 Jan 10 09:25:15.735538 vlab-01 ERR swss#orchagent: :- create: create status: SAI_STATUS_FAILURE
2025 Jan 10 09:25:15.735563 vlab-01 ERR swss#orchagent: :- RouteOrch: Failed to create IPv6 default route with packet action drop
2025 Jan 10 09:25:15.735619 vlab-01 INFO swss#supervisord: orchagent terminate called after throwing an instance of 'std::runtime_error'
2025 Jan 10 09:25:15.735638 vlab-01 INFO swss#supervisord: orchagent   what():  Failed to create IPv6 default route with packet action drop
2025 Jan 10 09:25:15.735771 vlab-01 ERR syncd#syncd_dash: :- processQuadEvent: attr: SAI_ROUTE_ENTRY_ATTR_PACKET_ACTION: SAI_PACKET_ACTION_DROP
2025 Jan 10 09:25:16.152182 vlab-01 INFO swss#supervisord 2025-01-10 09:25:16,151 WARN exited: orchagent (terminated by SIGABRT (core dumped); not expected)

[KrisNey-MSFT]

hi @jimmyzhai - all done with this one, ok to merge?

[jimmyzhai]

hi @jimmyzhai - all done with this one, ok to merge?

@r12f and @kcudnik are reviewing PR #657