From 529aa5e6f36e0c3bece7801a9dd281107e646cef Mon Sep 17 00:00:00 2001
From: Viacheslav Hletenko <v.gletenko@vyos.io>
Date: Sat, 4 Nov 2023 10:56:55 +0000
Subject: T5702: SNMP add interface-mib max-interfaces-number and prefix

- Allow to configure only required interface prefixes

  set service snmp mib interface 'eth'
  set service snmp mib interface 'bond'

 include_ifmib_iface_prefix eth bond

Sets the interface name prefixes to include in the IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls.
A set of space separated interface name prefixes will reduce the CPU
load for IF-MIB processing. For example, configuring
"include_ifmib_iface_prefix eth dummy lo" will include only interfaces
with these prefixes and ignore all others for IF-MIB processing.

- Allow to configure maximum interface number

  set service snmp mib interface-max '100'

  ifmib_max_num_ifaces NUM

Sets the maximum number of interfaces included in IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls
(on Linux). Setting a reasonable maximum for the CPU used will
reduce the CPU load for IF-MIB processing.  For example, configuring
"ifmib_max_num_ifaces 500" will include only the first 500 interfaces
based on ifindex and ignore all others for IF-MIB processing.

(cherry picked from commit 30a05ee1d447c6f92627162a506225f833a80f8c)
---
 data/templates/snmp/etc.snmpd.conf.j2 | 10 ++++
 interface-definitions/snmp.xml.in     | 95 +++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/data/templates/snmp/etc.snmpd.conf.j2 b/data/templates/snmp/etc.snmpd.conf.j2
index 9d78d479a..3db8c4d7b 100644
--- a/data/templates/snmp/etc.snmpd.conf.j2
+++ b/data/templates/snmp/etc.snmpd.conf.j2
@@ -56,6 +56,16 @@ SysDescr {{ description }}
 {% endif %}
 agentaddress unix:/run/snmpd.socket{{ ',' ~ options | join(',') if options is vyos_defined }}
 
+{% if mib is vyos_defined %}
+# Interface MIB limits
+{%     if mib.interface_max is vyos_defined %}
+ifmib_max_num_ifaces {{ mib.interface_max }}
+{%     endif %}
+{%     if mib.interface is vyos_defined %}
+include_ifmib_iface_prefix {{ mib.interface | join(' ') }}
+{%     endif %}
+{% endif %}
+
 # SNMP communities
 {% if community is vyos_defined %}
 {%     for comm, comm_config in community.items() %}
diff --git a/interface-definitions/snmp.xml.in b/interface-definitions/snmp.xml.in
index 0851b8389..ec2151b98 100644
--- a/interface-definitions/snmp.xml.in
+++ b/interface-definitions/snmp.xml.in
@@ -79,6 +79,101 @@
             </properties>
           </leafNode>
           #include <include/generic-description.xml.i>
+          <node name="mib">
+            <properties>
+              <help>Management information base (MIB)</help>
+            </properties>
+            <children>
+              <leafNode name="interface-max">
+                <properties>
+                  <help>Sets the maximum number of interfaces included in IF-MIB data collection</help>
+                  <valueHelp>
+                    <format>u32:1-4294967295</format>
+                    <description>Sets the maximum number of interfaces included in IF-MIB data collection</description>
+                  </valueHelp>
+                  <constraint>
+                    <validator name="numeric" argument="--range 1-4294967295"/>
+                  </constraint>
+                </properties>
+              </leafNode>
+              <leafNode name="interface">
+                <properties>
+                  <help>Sets the interface name prefix to include in the IF-MIB data collection</help>
+                  <completionHelp>
+                    <list>br bond dum eth gnv macsec peth sstpc tun veth vti vtun vxlan wg wlan wwan</list>
+                  </completionHelp>
+                  <valueHelp>
+                    <format>br</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>bond</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>dum</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>eth</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>gnv</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>macsec</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>peth</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>sstpc</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>tun</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>veth</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>vti</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>vtun</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>vxlan</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>wg</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>wlan</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>wwan</format>
+                    <description>Allow prefix for IF-MIB data collection</description>
+                  </valueHelp>
+                  <constraint>
+                    <regex>(br|bond|dum|eth|gnv|macsec|peth|sstpc|tun|veth|vti|vtun|vxlan|wg|wlan|wwan)</regex>
+                  </constraint>
+                  <multi/>
+                </properties>
+              </leafNode>
+            </children>
+          </node>
           <tagNode name="listen-address">
             <properties>
               <help>IP address to listen for incoming SNMP requests</help>
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