Add IPv6 link-local address handling

doc/sag/sag-HLD.md

@@ -67,6 +67,8 @@ The IP address configured on the VLAN interface is not changed.
 The VLAN interface will use static anycast gateway MAC address to replace CPU MAC address if static anycast gateway MAC address is specified and it's enabled on the VLAN interface.  
 The enable/disable knob on the VLAN interface can let user to determine to use CPU MAC or static anycast gateway MAC address.
 
+In IPv6 link-local address management, the system MAC generated IPv6 link-local to me route is added by RouteOrch in its initialization.  
+If the MAC address is changed between system and SAG, we need to call RouteOrch's API to delete old MAC gerenated IPv6 link-local to me route and then add new MAC generated IPv6 link-local to me route.
 The static anycast gateway on the VLAN interface will be disabled by default.
 
 The following diagram describes the sequence between DBs and modules.
@@ -131,6 +133,8 @@ Example:
 admin@edgecore:~$ sudo config static-anycast-gateway mac_address add 00:11:22:33:44:0f
 ```
 
+It doesn't allow to change SAG MAC via this command, the SAG MAC needs to be removed first.
+
 **Delete static anycast gateway MAC address**
 
 ```

doc/sag/sag-flow.wsd

@@ -3,6 +3,8 @@ boundary "CLI" as UI
 box "Orchagent" #LightGrey
     control IntfMgrD
     control IntfsOrch
+    control RouteOrch
+    control VrfOrch
 end box
 participant kernel
 box "DB" #LightBlue
@@ -23,13 +25,38 @@ IntfsOrch <-- APPL_DB
 IntfsOrch -> ASIC_DB: create router interface and change to SAG MAC address
 IntfMgrD -> APPL_DB: config VLAN interface IP
 IntfsOrch <-- APPL_DB
-IntfsOrch -> ASIC_DB: add IP2ME route and net route
+alt VLAN interface in default VRF
+    IntfsOrch -> RouteOrch: delete system MAC generated IPv6 link-local to me route
+    RouteOrch -> ASIC_DB: remove route entry
+    IntfsOrch -> RouteOrch: add SAG MAC generated IPv6 link-local to me route
+    RouteOrch -> ASIC_DB: add route entry
+else VLAN interface in VRF
+    IntfsOrch -> VrfOrch: delete system MAC generated IPv6 link-local to me route
+    VrfOrch -> RouteOrch
+    RouteOrch -> ASIC_DB: remove route entry
+    IntfsOrch -> VrfOrch: add SAG MAC generated IPv6 link-local to me router
+    VrfOrch -> RouteOrch
+    RouteOrch -> ASIC_DB: add route entry
+end
 group Disable SAG on the VLAN interface
     UI -> CONFIG_DB: disable SAG on the VLAN interface
     IntfMgrD <-- CONFIG_DB
     IntfMgrD -> kernel: change VLAN interface's MAC address to CPU MAC address
     IntfMgrD -> APPL_DB: Modify INTF_TABLE entry from SAG MAC address to CPU MAC address
     IntfsOrch <-- APPL_DB
     IntfsOrch -> ASIC_DB: change router interface's MAC address to CPU MAC address
+    alt VLAN interface in default VRF
+        IntfsOrch -> RouteOrch: delete SAG MAC generated IPv6 link-local to me route
+        RouteOrch -> ASIC_DB: remove route entry
+        IntfsOrch -> RouteOrch: add system MAC generated IPv6 link-local to me route
+        RouteOrch -> ASIC_DB: add route entry
+    else VLAN interface in VRF
+        IntfsOrch -> VrfOrch: delete SAG MAC generated IPv6 link-local to me route
+        VrfOrh -> RouteOrch
+        RouteOrch -> ASIC_DB: remove route entry
+        IntfsOrch -> VrfOrch: add system MAC generated IPv6 link-local to me route
+        VrfOrch -> RouteOrch
+        RouteOrch -> ASIC_DB: add route entry
+    end
 end
 @enduml