[mirrororch]: Implement HW resources availability validation for SPAN/ERSPAN (sonic-net#2187)

- What I did
Added a validation to prevent mirror session configuration if there is no available HW resources

- Why I did it
To prevent system from unexpected reboots
To add some debuggability information to the system journal

- How I verified it
Configure mirror sessions

Signed-off-by: Nazarii Hnydyn <[email protected]>

Author: nazariig

orchagent/mirrororch.cpp

@@ -352,15 +352,35 @@ bool MirrorOrch::validateSrcPortList(const string& srcPortList)
     return true;
 }
 
+bool MirrorOrch::isHwResourcesAvailable()
+{
+    uint64_t availCount = 0;
+
+    sai_status_t status = sai_object_type_get_availability(
+        gSwitchId, SAI_OBJECT_TYPE_MIRROR_SESSION, 0, nullptr, &availCount
+    );
+    if (status != SAI_STATUS_SUCCESS)
+    {
+        if (status == SAI_STATUS_NOT_SUPPORTED)
+        {
+            SWSS_LOG_WARN("Mirror session resource availability monitoring is not supported. Skipping ...");
+            return true;
+        }
+
+        return parseHandleSaiStatusFailure(handleSaiGetStatus(SAI_API_MIRROR, status));
+    }
+
+    return availCount > 0;
+}
+
 task_process_status MirrorOrch::createEntry(const string& key, const vector<FieldValueTuple>& data)
 {
     SWSS_LOG_ENTER();
 
     auto session = m_syncdMirrors.find(key);
     if (session != m_syncdMirrors.end())
     {
-        SWSS_LOG_NOTICE("Failed to create session, session %s already exists",
-                key.c_str());
+        SWSS_LOG_NOTICE("Failed to create session %s: object already exists", key.c_str());
         return task_process_status::task_duplicated;
     }
 
@@ -471,10 +491,13 @@ task_process_status MirrorOrch::createEntry(const string& key, const vector<Fiel
         }
     }
 
-    m_syncdMirrors.emplace(key, entry);
-
-    SWSS_LOG_NOTICE("Created mirror session %s", key.c_str());
+    if (!isHwResourcesAvailable())
+    {
+        SWSS_LOG_ERROR("Failed to create session %s: HW resources are not available", key.c_str());
+        return task_process_status::task_failed;
+    }
 
+    m_syncdMirrors.emplace(key, entry);
     setSessionState(key, entry);
 
     if (entry.type == MIRROR_SESSION_SPAN && !entry.dst_port.empty())
@@ -488,6 +511,8 @@ task_process_status MirrorOrch::createEntry(const string& key, const vector<Fiel
         m_routeOrch->attach(this, entry.dstIp);
     }
 
+    SWSS_LOG_NOTICE("Created mirror session %s", key.c_str());
+
     return task_process_status::task_success;
 }
 

orchagent/mirrororch.h

@@ -104,6 +104,8 @@ class MirrorOrch : public Orch, public Observer, public Subject
     // session_name -> VLAN | monitor_port_alias | next_hop_ip
     map<string, string> m_recoverySessionMap;
 
+    bool isHwResourcesAvailable();
+
     task_process_status createEntry(const string&, const vector<FieldValueTuple>&);
     task_process_status deleteEntry(const string&);