From 704ffd3f4b2da668157dc8053df65068ea5010c4 Mon Sep 17 00:00:00 2001
From: Matt Visnovsky <matt@visnovsky.us>
Date: Tue, 30 Apr 2024 15:18:25 -0600
Subject: [PATCH] Finalized SNMP monitor

---
 server/monitor-types/snmp.js | 69 +++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 28 deletions(-)

diff --git a/server/monitor-types/snmp.js b/server/monitor-types/snmp.js
index 1752ab717..2fa397161 100644
--- a/server/monitor-types/snmp.js
+++ b/server/monitor-types/snmp.js
@@ -1,5 +1,5 @@
 const { MonitorType } = require("./monitor-type");
-const { UP, DOWN } = require("../../src/util");
+const { UP, DOWN, log } = require("../../src/util");
 const snmp = require("net-snmp");
 
 class SNMPMonitorType extends MonitorType {
@@ -13,18 +13,17 @@ class SNMPMonitorType extends MonitorType {
      */
     async check(monitor, heartbeat, _server) {
 
-        console.log("IP Address:", monitor._hostname);
-        console.log("SNMP Community String:", monitor._snmpCommunityString);
-        console.log("SNMP OID:", monitor._snmpOid);
-        console.log("SNMP Version:", monitor._snmpVersion);
-        console.log("SNMP Condition:", monitor._snmpCondition);
-        console.log("SNMP Control Value:", monitor._snmpControlValue);
+        log.debug("monitor", `SNMP: Community String: ${monitor.snmpCommunityString}`);
+        log.debug("monitor", `SNMP: OID: ${monitor.snmpOid}`);
+        log.debug("monitor", `SNMP: Version: ${monitor.snmpVersion}`);
+        log.debug("monitor", `SNMP: Condition: ${monitor.snmpCondition}`);
+        log.debug("monitor", `SNMP: Control Value: ${monitor.snmpControlValue}`);
 
         const options = {
-            port: monitor._port || 161,
-            retries: 1,
+            port: monitor.port || '161',
+            retries: monitor.maxretries,
             timeout: 1000,
-            version: getKey(snmp.Version, monitor._snmpVersion) || snmp.Version2c,
+            version: getKey(snmp.Version, monitor.snmpVersion) || snmp.Version2c,
         };
 
         function getKey(obj, value) {
@@ -34,56 +33,70 @@ class SNMPMonitorType extends MonitorType {
         try {
             const session = snmp.createSession(monitor.hostname, monitor.snmpCommunityString, options);
 
+            // Handle errors during session creation
+            session.on('error', (error) => {
+                heartbeat.status = DOWN;
+                heartbeat.msg = `SNMP: Error creating SNMP session: ${error.message}`;
+                log.debug("monitor", `SNMP: ${heartbeat.msg}`);
+            });
+
             const varbinds = await new Promise((resolve, reject) => {
-                session.get([monitor._snmpOid], (error, varbinds) => {
+                session.get([monitor.snmpOid], (error, varbinds) => {
                     if (error) {
                         reject(error);
                     } else {
+                        log.debug("monitor", `SNMP: Received varbinds: Type: ${getKey(snmp.ObjectType, varbinds[0].type)}, Value: ${varbinds[0].value}`); // Log the received varbinds for debugging
                         resolve(varbinds);
                     }
                 });
             });
 
-            console.log("Received varbinds:", varbinds); // Log the received varbinds for debugging
-
-            if (varbinds && varbinds.length > 0) {
+            if (varbinds.length === 0 || getKey(snmp.ObjectType, varbinds[0].type) === 'NoSuchInstance') {
+                throw new Error(`No varbinds returned from SNMP session (OID: ${monitor.snmpOid})`);
+            } else {
                 const value = varbinds[0].value;
                 const numericValue = parseInt(value);
-                const stringValue = value.toString();
+                const stringValue = value.toString('ascii');
 
                 switch (monitor.snmpCondition) {
                     case '>':
-                        heartbeat.status = numericValue > monitor._snmpControlValue ? UP : DOWN;
+                        heartbeat.status = numericValue > monitor.snmpControlValue ? UP : DOWN;
                         break;
                     case '>=':
-                        heartbeat.status = numericValue >= monitor._snmpControlValue ? UP : DOWN;
+                        heartbeat.status = numericValue >= monitor.snmpControlValue ? UP : DOWN;
                         break;
                     case '<':
-                        heartbeat.status = numericValue < monitor._snmpControlValue ? UP : DOWN;
+                        heartbeat.status = numericValue < monitor.snmpControlValue ? UP : DOWN;
                         break;
                     case '<=':
-                        heartbeat.status = numericValue <= monitor._snmpControlValue ? UP : DOWN;
+                        heartbeat.status = numericValue <= monitor.snmpControlValue ? UP : DOWN;
                         break;
                     case '==':
-                        heartbeat.status = value === monitor._snmpControlValue ? UP : DOWN;
+                        if (!isNaN(value) && !isNaN(monitor.snmpControlValue)) {
+                            // Both values are numeric, parse them as numbers
+                            heartbeat.status = parseFloat(value) === parseFloat(monitor.snmpControlValue) ? UP : DOWN;
+                        } else {
+                            // At least one of the values is not numeric, compare them as strings
+                            heartbeat.status = value.toString() === monitor.snmpControlValue.toString() ? UP : DOWN;
+                        }
                         break;
                     case 'contains':
-                        heartbeat.status = stringValue.includes(monitor._snmpControlValue) ? UP : DOWN;
+                        heartbeat.status = stringValue.includes(monitor.snmpControlValue) ? UP : DOWN;
                         break;
                     default:
                         heartbeat.status = DOWN;
-                        heartbeat.msg = `Invalid condition: ${monitor._snmpCondition}`;
+                        heartbeat.msg = `Invalid condition: ${monitor.snmpCondition}`;
+                        break;
                 }
-            } else {
-                heartbeat.status = DOWN;
-                heartbeat.msg = 'No varbinds returned from SNMP session';
-            }
+                heartbeat.msg = `SNMP value ` + (heartbeat.status ? `passes` : `does not pass`) + ` comparison: ${value.toString('ascii')} ${monitor.snmpCondition} ${monitor.snmpControlValue}`;
 
+            }
             session.close(); // Close the session after use
+
         } catch (err) {
-            console.error("Error in SNMP check:", err); // Log any errors
             heartbeat.status = DOWN;
-            heartbeat.msg = `Error: ${err.message}`;
+            heartbeat.msg = `SNMP Error: ${err.message}`;
+            log.debug("monitor", `SNMP: ${heartbeat.msg}`);
         }
     }