How to create a walkable snmpd extension using pass_persist with shell script

Question

I have added the following 2 lines to my snmpd.conf file:

view all included .1.3.6.1.4.1.8072.9999.9999
pass_persist .1.3.6.1.4.1.8072.9999.9999 /root/kshtest

I have created a shell script (/root/kshtest) that takes a file, OIDDEFS, containing lines with each OID, its type, and its value (separated by a space):

.1.3.6.1.4.1.8072.9999.9999.1.1 integer 35
.1.3.6.1.4.1.8072.9999.9999.1.2 integer 21
.1.3.6.1.4.1.8072.9999.9999.1.3 integer 56
.1.3.6.1.4.1.8072.9999.9999.2.1 integer 3592
.1.3.6.1.4.1.8072.9999.9999.2.2 integer 2234
.1.3.6.1.4.1.8072.9999.9999.2.3 integer 4499
.1.3.6.1.4.1.8072.9999.9999.2.4 integer 2233
.1.3.6.1.4.1.8072.9999.9999.3.1 integer 6650
.1.3.6.1.4.1.8072.9999.9999.3.2 integer 6650
.1.3.6.1.4.1.8072.9999.9999.3.3 integer 6650
.1.3.6.1.4.1.8072.9999.9999.3.4 integer 6650
.1.3.6.1.4.1.8072.9999.9999.4.1 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.2 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.3 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.4 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.5 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.6 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.7 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.8 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.9 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.10 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.11 integer 0
.1.3.6.1.4.1.8072.9999.9999.4.12 integer 0

and provides the following interaction when run from the command line:

<- PING 

-> PONG 

<- get 

<- .1.3.6.1.4.1.8072.9999.9999.1.1 

-> .1.3.6.1.4.1.8072.9999.9999.1.1 

-> integer 

-> 35

<- PING 

-> PONG 

<- getnext 

<- .1.3.6.1.4.1.8072.9999.9999.1.1 

-> .1.3.6.1.4.1.8072.9999.9999.1.2 

-> integer 

-> 21

The script's contents are as follows (but I think all you may need to know is that it works as shown above):

#!/usr/pkg/bin/ksh93

OIDDEFS=OIDDEFS
IFS=$'\n'
lines=($(< $OIDDEFS))
typeset -A gettype
typeset -A getvalue
typeset -A getnextoid
typeset -A getnexttype
typeset -A getnextvalue
for (( x=0; x<${#lines[*]}; ((x++)) ))
  do IFS=$'\t\n '
  words=($(echo ${lines[x]}))
  gettype[${words[0]}]=${words[1]}
  getvalue[${words[0]}]=$(printf "%i\n" ${words[2]})
  if [[ x -gt 0 ]]; then
    getnextoid[${lines[x-1]%% *}]=${words[0]}
    getnexttype[${lines[x-1]%% *}]=${words[1]}
    getnextvalue[${lines[x-1]%% *}]=$(printf "%i\n" ${words[2]})
  fi
done
while true
  do read
  if [[ $REPLY == "PING" ]]; then
    echo PONG
  else
    exit 1
  fi
  x=0
  while [[ x -lt 2 ]];
    do read REPLY$x
    ((x++))
  done
  if [[ $REPLY0 == get ]]; then
    echo $REPLY1
    echo ${gettype[$REPLY1]}
    echo ${getvalue[$REPLY1]}
  fi
  if [[ $REPLY0 == getnext ]]; then
    if [[ ! -v getnextoid[$REPLY1] ]]; then
      echo NONE
    else
      echo ${getnextoid[$REPLY1]}
      echo ${getnexttype[$REPLY1]}
      echo ${getnextvalue[$REPLY1]}
    fi
  fi
done

I can run 'snmpd -f' (although I don't understand why it won't work without the -f flag) and do a

snmpgetnext -On -v 2c -c public 127.0.0.1 .1.3.6.1.4.1.8072.9999.9999.1.1

and get the response:

.1.3.6.1.4.1.8072.9999.9999.1.2 = INTEGER: 21

I can successfully snmpget (net-snmp command) any of the oids in my MIB and get their values or snmpgetnext any oid and get the next oid and value. However, I cannot snmpwalk my oids. When I

snmpwalk -On -v 2c -c public 127.0.0.1 .1.3.6.1.4.1.8072.9999.9999.1.1

I get

.1.3.6.1.4.1.8072.9999.9999.1.1 = INTEGER: 35

which is the same response I get from an snmpget on that oid.

snmpwalk -d -v 2c -c public 127.0.0.1 .1.3.6.1.4.1.8072.9999.9999.1.1

gives me:

Sending 48 bytes to UDP: [127.0.0.1]:161->[0.0.0.0]:0
0000: 30 2E 02 01  01 04 06 70  75 62 6C 69  63 A1 21 02    0......public.!.
0016: 04 7F 15 82  9A 02 01 00  02 01 00 30  13 30 11 06    ...........0.0..
0032: 0D 2B 06 01  04 01 BF 08  CE 0F CE 0F  01 01 05 00    .+..............


Received 49 byte packet from UDP: [127.0.0.1]:161->[0.0.0.0]:65489
0000: 30 2F 02 01  01 04 06 70  75 62 6C 69  63 A2 22 02    0/.....public.".
0016: 04 7F 15 82  9A 02 01 00  02 01 00 30  14 30 12 06    ...........0.0..
0032: 0D 2B 06 01  04 01 BF 08  CE 0F CE 0F  01 02 02 01    .+..............
0048: 15                                                    .


Sending 48 bytes to UDP: [127.0.0.1]:161->[0.0.0.0]:0
0000: 30 2E 02 01  01 04 06 70  75 62 6C 69  63 A0 21 02    0......public.!.
0016: 04 7F 15 82  9B 02 01 00  02 01 00 30  13 30 11 06    ...........0.0..
0032: 0D 2B 06 01  04 01 BF 08  CE 0F CE 0F  01 01 05 00    .+..............


Received 49 byte packet from UDP: [127.0.0.1]:161->[0.0.0.0]:65489
0000: 30 2F 02 01  01 04 06 70  75 62 6C 69  63 A2 22 02    0/.....public.".
0016: 04 7F 15 82  9B 02 01 00  02 01 00 30  14 30 12 06    ...........0.0..
0032: 0D 2B 06 01  04 01 BF 08  CE 0F CE 0F  01 01 02 01    .+..............
0048: 23                                                    #

NET-SNMP-MIB::monoCount = INTEGER: 35

which appears to be an snmpgetnext to .1.3.6.1.4.1.8072.9999.9999.1.1, followed by an snmpgetresponse referencing .1.3.6.1.4.1.8072.9999.9999.1.2, followed by an snmpget for .1.3.6.1.4.1.8072.9999.9999.1.1, followed by an snmpgetresponse referencing .1.3.6.1.4.1.8072.9999.9999.1.1.

My NET-SNMP-MIB.txt file, which I altered to add the MIB values is as follows:

NET-SNMP-MIB DEFINITIONS ::= BEGIN

--
-- Top-level infrastructure of the Net-SNMP project enterprise MIB tree
--

IMPORTS
    MODULE-IDENTITY, Integer32, enterprises FROM SNMPv2-SMI;

netSnmp MODULE-IDENTITY
    LAST-UPDATED "200201300000Z"
    ORGANIZATION "www.net-snmp.org"
    CONTACT-INFO    
     "postal:   Wes Hardaker
                    P.O. Box 382
                    Davis CA  95617

          email:    net-snmp-coders@lists.sourceforge.net"
    DESCRIPTION
    "Top-level infrastructure of the Net-SNMP project enterprise MIB tree"
    REVISION     "200201300000Z"
    DESCRIPTION
    "First draft"
    ::= { enterprises 8072}


--
--  Net-SNMP enterprise-specific management objects
--

netSnmpObjects              OBJECT IDENTIFIER ::= {netSnmp 1}
-- netSnmpExamples             OBJECT IDENTIFIER ::= {netSnmp 2}
netSnmpEnumerations         OBJECT IDENTIFIER ::= {netSnmp 3}
netSnmpModuleIDs            OBJECT IDENTIFIER ::= {netSnmpEnumerations 1}
netSnmpAgentOIDs            OBJECT IDENTIFIER ::= {netSnmpEnumerations 2}
netSnmpDomains              OBJECT IDENTIFIER ::= {netSnmpEnumerations 3}
netSnmpExperimental         OBJECT IDENTIFIER ::= {netSnmp 9999}

--
-- A subtree specifically designed for private testing purposes.
-- No "public" management objects should ever be defined within this tree.
--
-- It is provided for private experimentation, prior to transferring a MIB
-- structure to another part of the overall OID tree
--
netSnmpPlaypen              OBJECT IDENTIFIER ::= {netSnmpExperimental 9999}


--
--  Notifications
--

netSnmpNotificationPrefix   OBJECT IDENTIFIER ::= {netSnmp 4}
netSnmpNotifications        OBJECT IDENTIFIER ::= {netSnmpNotificationPrefix 0}
netSnmpNotificationObjects  OBJECT IDENTIFIER ::= {netSnmpNotificationPrefix 1}


--
--  Conformance
--     (No laughing at the back!)
--

netSnmpConformance          OBJECT IDENTIFIER ::= {netSnmp 5}
netSnmpCompliances          OBJECT IDENTIFIER ::= {netSnmpConformance 1}
netSnmpGroups               OBJECT IDENTIFIER ::= {netSnmpConformance 2}

-- start additions:
pageCountsVals              OBJECT IDENTIFIER ::= {netSnmpPlaypen 1}
tonerLevelsVals             OBJECT IDENTIFIER ::= {netSnmpPlaypen 2}
tonerLevelsMaxVals          OBJECT IDENTIFIER ::= {netSnmpPlaypen 3}
otherRandomVals             OBJECT IDENTIFIER ::= {netSnmpPlaypen 4}

monoCount                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {pageCountsVals 1}

colorCount                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {pageCountsVals 2}

totalCount                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {pageCountsVals 3}

cyanVal                      OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsVals 1}

magentaVal                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsVals 2}

yellowVal                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsVals 3}

blackVal                     OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsVals 4}

cyanMaxVal                      OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsMaxVals 1}

magentaMaxVal                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsMaxVals 2}

yellowMaxVal                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsMaxVals 3}

blackMaxVal                     OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {tonerLevelsMaxVals 4}

randomVal1                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 1}

randomVal2                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 2}

randomVal3                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 3}

randomVal4                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 4}

randomVal5                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 5}

randomVal6                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 6}

randomVal7                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 7}

randomVal8                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 8}

randomVal9                    OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 9}

randomVal10                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 10}

randomVal11                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 11}

randomVal12                   OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DEFVAL      { 0 }
    ::= {otherRandomVals 12}

END

I am hoping that this will give an experienced snmp'er enough info to see what I am doing wrong. If not, please ask. Thanks.

Thanks a lot for this detailed question, helped me with net-snmp recently! — Yarek T, Jul 01 '22 at 07:50

score 0 · Answer 1 · answered Feb 10 '15 at 18:18

0

Snmpwalk gets all OIDs in the tree under the OID you specify. Since you specified .1.3.6.1.4.1.8072.9999.9999.1.1, it gets only that specific OID, since there are no other OIDs under that one. To walk all of the OIDS you've defined, do this:

snmpwalk -On -v 2c -c public 127.0.0.1 .1.3.6.1.4.1.8072.9999.9999

answered Feb 10 '15 at 18:18

John Stevens

216
1
8

1

following the example snmpd -f does have different behaviour than when snmpd is run as a service or from init.d. Walk/or Get fails no matter how you address the OID. – PodTech.io Jul 19 '16 at 18:22

PodTech.io · Answer 2 · 2016-07-19T20:27:50.583

0

@user1693487 The issue is your 3rd line;

OIDDEFS=OIDDEFS

When run as a service/init.d, this needs a full path;

OIDDEFS=/usr/bla/path/OIDDEFS

Either way, your post helped me out as I was facing the same issue!! so thanks

edited Jul 19 '16 at 20:27

answered Jul 19 '16 at 19:14

PodTech.io

4,874
41
24

How to create a walkable snmpd extension using pass_persist with shell script

2 Answers2