Update to support SAI BFD_SESSION_OFFLOAD_TYPE. (#1546)

Adding support for SAI_SWITCH_ATTR_SUPPORTED_IPV4_BFD_SESSION_OFFLOAD_TYPE and SAI_SWITCH_ATTR_SUPPORTED_IPV6_BFD_SESSION_OFFLOAD_TYPE in vslib. This is needed by BfdOrch in sonic-swss to choose between software BFD or regular (offloaded) BFD.

Default will be to return SAI_BFD_SESSION_OFFLOAD_TYPE_FULL, as this was the default behavior previously when this value was not checked.

Added capability to return SAI_BFD_SESSION_OFFLOAD_TYPE_NONE by setting SAI_VS_BFD_OFFLOAD_SUPPORTED=false in sai.profile for testing and in cases where software BFD is desired.

Author: dypet

vslib/Sai.cpp

@@ -152,6 +152,9 @@ sai_status_t Sai::apiInitialize(
 
     auto useTapDevice = SwitchConfig::parseBool(use_tap_dev);
 
+    const char *bfd_offload_supported = service_method_table->profile_get_value(0, SAI_KEY_VS_BFD_OFFLOAD_SUPPORTED);
+    auto bfdOffloadSupported = SwitchConfig::parseBfdOffloadSupported(bfd_offload_supported);
+
     SWSS_LOG_NOTICE("hostif use TAP device: %s", (useTapDevice ? "true" : "false"));
 
     const char *use_configured_speed_as_oper_speed = service_method_table->profile_get_value(0, SAI_KEY_VS_USE_CONFIGURED_SPEED_AS_OPER_SPEED);
@@ -226,6 +229,7 @@ sai_status_t Sai::apiInitialize(
         sc->m_useTapDevice = useTapDevice;
         sc->m_useConfiguredSpeedAsOperSpeed = useConfiguredSpeedAsOperSpeed;
         sc->m_laneMap = m_laneMapContainer->getLaneMap(sc->m_switchIndex);
+        sc->m_bfdOffload = bfdOffloadSupported;
 
         if (sc->m_laneMap == nullptr)
         {

vslib/SwitchConfig.cpp

@@ -18,6 +18,7 @@ SwitchConfig::SwitchConfig(
     m_switchIndex(switchIndex),
     m_hardwareInfo(hwinfo),
     m_useTapDevice(false),
+    m_bfdOffload(true),
     m_useConfiguredSpeedAsOperSpeed(false)
 {
     SWSS_LOG_ENTER();
@@ -154,3 +155,16 @@ bool SwitchConfig::parseBool(
 
     return false;
 }
+
+bool SwitchConfig::parseBfdOffloadSupported(
+    _In_ const char* bfdOffloadSupportedStr)
+{
+    SWSS_LOG_ENTER();
+
+    if (bfdOffloadSupportedStr)
+    {
+        return strcmp(bfdOffloadSupportedStr, "true") == 0;
+    }
+
+    return true;
+}

vslib/SwitchConfig.h

@@ -67,6 +67,9 @@ namespace saivs
             static bool parseBool(
                     _In_ const char* boolStr);
 
+            static bool parseBfdOffloadSupported(
+                    _In_ const char* bfdOffloadSupportedStr);
+
         public:
 
             sai_switch_type_t m_saiSwitchType;
@@ -81,6 +84,8 @@ namespace saivs
 
             bool m_useTapDevice;
 
+            bool m_bfdOffload;
+
             bool m_useConfiguredSpeedAsOperSpeed;
 
             std::shared_ptr<LaneMap> m_laneMap;

vslib/SwitchStateBase.cpp

@@ -1055,6 +1055,24 @@ sai_status_t SwitchStateBase::set_switch_default_attributes()
 
     CHECK_STATUS(set(SAI_OBJECT_TYPE_SWITCH, m_switch_id, &attr));
 
+    attr.id = SAI_SWITCH_ATTR_SUPPORTED_IPV4_BFD_SESSION_OFFLOAD_TYPE;
+    uint32_t list[1] = { SAI_BFD_SESSION_OFFLOAD_TYPE_FULL };
+
+    if(!m_switchConfig->m_bfdOffload) {
+        list[0] = SAI_BFD_SESSION_OFFLOAD_TYPE_NONE;
+    }
+
+    attr.value.u32list.count = 1;
+    attr.value.u32list.list = list;
+
+    CHECK_STATUS(set(SAI_OBJECT_TYPE_SWITCH, m_switch_id, &attr));
+
+    attr.id = SAI_SWITCH_ATTR_SUPPORTED_IPV6_BFD_SESSION_OFFLOAD_TYPE;
+    attr.value.u32list.count = 1;
+    attr.value.u32list.list = list;
+
+    CHECK_STATUS(set(SAI_OBJECT_TYPE_SWITCH, m_switch_id, &attr));
+
     return set_switch_supported_object_types();
 }
 
@@ -2480,6 +2498,10 @@ sai_status_t SwitchStateBase::refresh_read_only(
             case SAI_SWITCH_ATTR_AVAILABLE_DOUBLE_NAT_ENTRY:
                 return SAI_STATUS_SUCCESS;
 
+            case SAI_SWITCH_ATTR_SUPPORTED_IPV4_BFD_SESSION_OFFLOAD_TYPE:
+            case SAI_SWITCH_ATTR_SUPPORTED_IPV6_BFD_SESSION_OFFLOAD_TYPE:
+                return SAI_STATUS_SUCCESS;
+
             case SAI_SWITCH_ATTR_NUMBER_OF_SYSTEM_PORTS:
             case SAI_SWITCH_ATTR_SYSTEM_PORT_LIST:
                 return refresh_system_port_list(meta);

vslib/saivs.h

@@ -56,6 +56,19 @@ extern "C" {
  */
 #define SAI_KEY_VS_HOSTIF_USE_TAP_DEVICE      "SAI_VS_HOSTIF_USE_TAP_DEVICE"
 
+/**
+ * @def SAI_KEY_VS_BFD_OFFLOAD_SUPPORTED
+ *
+ * Bool flag, (true/false). If set to false, then platform will be configured
+ * to return SAI_BFD_SESSION_OFFLOAD_TYPE_NONE for
+ * SAI_SWITCH_ATTR_SUPPORTED_IPV4_BFD_SESSION_OFFLOAD_TYPE and
+ * SAI_SWITCH_ATTR_SUPPORTED_IPV6_BFD_SESSION_OFFLOAD_TYPE calls; otherwise
+ * SAI_BFD_SESSION_OFFLOAD_TYPE_FULL will be set.
+ *
+ * By default this flag is set to true.
+ */
+ #define SAI_KEY_VS_BFD_OFFLOAD_SUPPORTED     "SAI_VS_BFD_OFFLOAD_SUPPORTED"
+
 /**
  * @def SAI_KEY_VS_USE_CONFIGURED_SPEED_AS_OPER_SPEED
  *