[cbf] Add class-based forwarding support (sonic-net#1963)

* [cbf] Added initial CBF support (#2)

* Added CBF NHG support to NhgOrch
* Added NhgMapOrch to handle DSCP_TO_FC and EXP_TO_FC tables
* Added UT for the new NhgOrch function and NhgMapOrch

Support sonic-net/SONiC#796

Co-authored-by: Alexandru Banu <v-albanu@microsoft.com>

doc/Configuration.md

@@ -1129,6 +1129,8 @@ name as object key and member list as attribute.
  "pfc_enable": "3,4", 
  "pfc_to_queue_map": "AZURE", 
  "dscp_to_tc_map": "AZURE",
+ "dscp_to_fc_map": "AZURE",
+ "exp_to_fc_map": "AZURE",
  "scheduler": "scheduler.port"
  }
  }

doc/swss-schema.md

@@ -194,6 +194,28 @@ and reflects the LAG ports into the redis under: `LAG_TABLE:<team0>:port`
  mpls_nh = STRING ; Comma-separated list of MPLS NH info.
  weight = weight_list ; List of weights.
 
+---------------------------------------------
+### CLASS_BASED_NEXT_HOP_GROUP_TABLE
+ ;Stores a list of groups of one or more next hop groups used for class based forwarding
+ ;Status: Mandatory
+ key = CLASS_BASED_NEXT_HOP_GROUP_TABLE:string ; arbitrary index for the next hop group
+ members = NEXT_HOP_GROUP_TABLE.key ; one or more separated by ","
+ selection_map = FC_TO_NHG_INDEX_MAP_TABLE.key ; the NHG map to use for this CBF NHG
+
+---------------------------------------------
+### FC_TO_NHG_INDEX_MAP_TABLE
+ ; FC to Next hop group index map
+ key = "FC_TO_NHG_INDEX_MAP_TABLE:"name
+ fc_num = 1*DIGIT ;value
+ nh_index = 1*DIGIT; index of NH inside NH group
+
+ Example:
+ 127.0.0.1:6379> hgetall "FC_TO_NHG_INDEX_MAP_TABLE:AZURE"
+  1) "0" ;fc_num
+  2) "0" ;nhg_index
+  3) "1"
+  4) "0"
+
 ---------------------------------------------
 ### NEIGH_TABLE
  ; Stores the neighbors or next hop IP address and output port or
@@ -321,6 +343,41 @@ and reflects the LAG ports into the redis under: `LAG_TABLE:<team0>:port`
   9) "4"
  10) "8"
 
+### DSCP_TO_FC_TABLE_NAME
+ ; dscp to FC map
+ ;SAI mapping - qos_map object with SAI_QOS_MAP_ATTR_TYPE == sai_qos_map_type_t::SAI_QOS_MAP_TYPE_DSCP_TO_FORWARDING_CLASS
+ key = "DSCP_TO_FC_MAP_TABLE:"name
+ ;field value
+ dscp_value = 1*DIGIT
+ fc_value = 1*DIGIT
+
+ Example:
+ 127.0.0.1:6379> hgetall "DSCP_TO_FC_MAP_TABLE:AZURE"
+  1) "0" ;dscp
+  2) "1" ;fc
+  3) "1"
+  4) "1"
+  5) "2"
+  6) "3"
+  7)
+---------------------------------------------
+### EXP_TO_FC_MAP_TABLE
+ ; dscp to FC map
+ ;SAI mapping - qos_map object with SAI_QOS_MAP_ATTR_TYPE == sai_qos_map_type_t::SAI_QOS_MAP_TYPE_MPLS_EXP_TO_FORWARDING_CLASS
+ key = "EXP_TO_FC_MAP_TABLE:"name
+ ;field value
+ mpls_exp_value = 1*DIGIT
+ fc_value = 1*DIGIT
+
+ Example:
+ 127.0.0.1:6379> hgetall "EXP_TO_FC_MAP_TABLE:AZURE"
+  1) "0" ;mpls_exp
+  2) "1" ;fc
+  3) "1"
+  4) "1"
+  5) "2"
+  6) "3"
+
 ---------------------------------------------
 ### SCHEDULER_TABLE
  ; Scheduler table

orchagent/Makefile.am

@@ -3,7 +3,8 @@ INCLUDES = -I $(top_srcdir)/lib \
  -I $(top_srcdir)/warmrestart \
  -I flex_counter \
  -I debug_counter \
- -I pbh
+ -I pbh \
+ -I nhg
 
 CFLAGS_SAI = -I /usr/include/sai
 
@@ -40,7 +41,10 @@ orchagent_SOURCES = \
  orchdaemon.cpp \
  orch.cpp \
  notifications.cpp \
- nhgorch.cpp \ 
+ nhgorch.cpp \
+ nhgbase.cpp \
+ cbf/cbfnhgorch.cpp \
+ cbf/nhgmaporch.cpp \
  routeorch.cpp \
  mplsrouteorch.cpp \
  neighorch.cpp \