[c-nsp] SNMP: IP => vlan + mac

[Liviu Pislaru]

I don't want to use "grep" because i have more than 1000 arp entry per vlan.

On Friday 27 August 2004 02:59, Virgil wrote:
> > Is there a posibility to obtain via SNMP a mac-address
> > (0007.eb95.9b80) from arp table for IP address 10.5.16.7 ?
>
> This might be of use to you.  It's a dodgy shell script that's crying
> out to be converted to perl net-snmp.
> If anyone feels the urge, please send me a copy.
>
> #!/bin/bash
> # locates a switch port in the access layer from an IP address.
> # query starts at the core 6500
>
> READONLY=public
> SW=$1
> IPADDRESS=$2
>
>
> arpMeBaby() {
>         #MAC address of ${IPADDRESS}
>         snmpwalk -On -v2c -c${READONLY} ${1} atPhysAddress | grep "${2}
> =" | cut -d" " -f4-
> }
>
>
> getVlanif() {
>         snmpwalk -Onq -v2c -c${READONLY} ${1} ipNetToMediaPhysAddress |
> grep "${2} " | awk ' {split($1,vi,".1.3.6.1.2.1.4.22.1.2."); print
> vi[2]}'  | awk 'BEGIN { FS = "." } ; { print $1}'
> }
>
>
> getVlan() {
>         #IF-MIB::ifName.204 = STRING: Vl11
>         snmpwalk -On -v2c -c${READONLY} ${1} ifName.${2} | awk '{print
> $4}' | cut -c3-
> }
>
>
> macSuck() {
>         #For this VLAN, get the MAC address table (using community
> string indexing!) dot1dTpFdbAddress
>         snmpwalk -On -v2c -c${READONLY}@${Vlan} ${1}
> .1.3.6.1.2.1.17.4.3.1.1 | grep "${2}" | cut -d"." -f13-18 | cut -d" "
> -f1
> }
>
> whichPort() {
>         #Get the bridge port number, dot1dTpFdbPort
> (.1.3.6.1.2.1.17.4.3.1.2) for this MAC
>         snmpwalk -Onv -v2c -c${READONLY}@${2} ${1}
> .1.3.6.1.2.1.17.4.3.1.2.${3} | cut -d" " -f2
> }
>
> findifIndex() {
>         #For this VLAN, get the bridge port to ifIndex
> (1.3.6.1.2.1.2.2.1.1) mapping,
>         #dot1dBasePortIfIndex (.1.3.6.1.2.1.17.1.4.1.2):
>         snmpwalk -Ovn -v2c -c${READONLY}@${2} ${1}
> .1.3.6.1.2.1.17.1.4.1.2.${3} | cut -d" " -f2
> }
>
> portName() {
>         #Walk the ifName (.1.3.6.1.2.1.31.1.1.1.1) so that the ifIndex
> value
>         #can be correllated with a proper port name:
>         snmpwalk -Oqn -v2c -c${READONLY}@${2} ${1} ifName.${3} | cut -d"
> " -f2
> }
>
> portDesc() {
>         #Get the description (.1.3.6.1.2.1.31.1.1.1.18)
>         snmpwalk -Oqn -v2c -c${READONLY}@${2} ${1} ifAlias.${3} | cut
> -d" " -f2-
> }
>
> cdpNei() {
>         #Find the CDP neighbor (.1.3.6.1.4.1.9.9.23.1.2.1.1.6) for the
> next hop.
>         snmpwalk -Ovn -v2c -c${READONLY}@${2} ${1}
> 1.3.6.1.4.1.9.9.23.1.2.1.1.6.${3} | cut -f2 -d\"
> }
> cdpNeiPort() {
>         snmpwalk -Ovn -v2c -c${READONLY}@${2} ${1}
> 1.3.6.1.4.1.9.9.23.1.2.1.1.7.${3} | cut -f2 -d\"
> }
>
> target=${SW}
>
> VlanifIndex=`getVlanif ${target} ${IPADDRESS}`
> Vlan=`getVlan ${target} $VlanifIndex`
> Arp=`arpMeBaby ${target} ${IPADDRESS}`
> MAC=`macSuck ${target} "${Arp}"`
> PortNo=`whichPort ${target} ${Vlan} $MAC`
> ifIndex=`findifIndex ${target} ${Vlan} $PortNo`
> if=`portName ${target} ${Vlan} $ifIndex`
> ifDesc=`portDesc ${target} ${Vlan} $ifIndex`
> CdpNei=`cdpNei ${target} ${Vlan} $ifIndex`
> CdpNeiPort=`cdpNeiPort ${target} ${Vlan} $ifIndex`
>
> target=${CdpNei}
> AccessSwPortNo=`whichPort ${target} ${Vlan} $MAC`
> AccessSwifIndex=`findifIndex ${target} ${Vlan} $AccessSwPortNo`
> AccessSwif=`portName ${target} ${Vlan} $AccessSwifIndex`
> AccessSwifDesc=`portDesc ${target} ${Vlan} $AccessSwifIndex`
>
> #echo -ne "${IPADDRESS} is in Vlan ${Vlan}\n${SW} [${if}] -> ${CdpNei}
> [${CdpNeiPort}]\n${CdpNei} [$AccessSwif] -> ${AccessSwifDesc}\n"
>
> echo -ne "$target [$AccessSwif] -> ${AccessSwifDesc}\n"
>
> Regards,
>
> Virgil

-- 
Liviu Pislaru -- Tech Department
Romania Data Systems - NOC in Bucharest
Phone: +4-021-30.10.888  Fax: +4-021-30.10.892
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