From b89ebabeccbd7948aa0f54e9736d602e78bb2126 Mon Sep 17 00:00:00 2001
From: Neil Lathwood <neil@lathwood.co.uk>
Date: Fri, 28 Oct 2016 07:02:09 +0100
Subject: [PATCH] Feature: Added support for global max repeaters for snmp
 (#4880)

* Feature: Added support for global max repeaters for snmp

* added phpdoc
---
 doc/Support/Performance.md | 13 ++++++++++++-
 includes/snmp.inc.php      | 21 ++++++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/doc/Support/Performance.md b/doc/Support/Performance.md
index 66af33d48b..f4fc343fa8 100644
--- a/doc/Support/Performance.md
+++ b/doc/Support/Performance.md
@@ -42,13 +42,24 @@ You can disable modules globally then re-enable the module per device or the opp
 We have support for SNMP Max repeaters which can be handy on devices where we poll a lot of ports or bgp sessions for instance and 
 where snmpwalk or snmpbulkwalk is used. This needs to be enabled on a per device basis under edit device -> snmp -> Max repeaters.
 
+You can also set this globally with the config option `$config['snmp']['max_repeaters'] = X;`.
+
 It's advisable to test the time taken to snmpwalk IF-MIB or something similar to work out what the best value is. To do this run the following 
 but replace <REPEATERS> with varying numbers from 10 upto around 50. You will also need to set the correct snmp version, hostname and community string:
 
-`time snmpbulkwalk -v2c -cpublic HOSTNAME -Cr<REPEATERS> -M /opt/librenms/mibs -m IF-MIB`
+`time snmpbulkwalk -v2c -cpublic HOSTNAME -Cr<REPEATERS> -M /opt/librenms/mibs -m IF-MIB IfEntry`
 
 > NOTE: Do not go blindly setting this value as you can impact polling negatively.
 
+#### SNMP Max OIDs
+
+For sensors polling we now do bulk snmp gets to speed things up. By default this is ten but you can overwrite this per device under 
+edit device -> snmp -> Max OIDs.
+
+You can also set this globally with the config option `$config['snmp']['max_oid'] = X;`.
+
+> NOTE: It is advisable to monitor sensor polling when you change this to ensure you don't set the value too high.
+
 #### Optimise poller-wrapper
 
 The default 16 threads that `poller-wrapper.py` runs as isn't necessarily the optimal number. A general rule of thumb is 
diff --git a/includes/snmp.inc.php b/includes/snmp.inc.php
index c10f82a794..92d5c7498a 100644
--- a/includes/snmp.inc.php
+++ b/includes/snmp.inc.php
@@ -102,7 +102,7 @@ function gen_snmpwalk_cmd($device, $oids, $options = null, $mib = null, $mibdir
         $snmpcmd = $config['snmpwalk'];
     } else {
         $snmpcmd = $config['snmpbulkwalk'];
-        $max_repeaters = $device['snmp_max_repeaters'];
+        $max_repeaters = get_device_max_repeaters($device);
         if ($max_repeaters > 0) {
             $snmpcmd .= " -Cr$max_repeaters ";
         }
@@ -1147,3 +1147,22 @@ function snmpwalk_array_num($device, $oid, $indexes = 1)
     }
     return $array;
 }
+
+/**
+ * @param $device
+ * @return bool
+ */
+function get_device_max_repeaters($device)
+{
+    global $config;
+
+    $max_repeaters = $device['snmp_max_repeaters'];
+
+    if (isset($max_repeaters) && $max_repeaters > 0) {
+        return $max_repeaters;
+    } elseif (isset($config['snmp']['max_repeaters']) && $config['snmp']['max_repeaters'] > 0) {
+        return $config['snmp']['max_repeaters'];
+    } else {
+        return false;
+    }
+}