An AWK script to parse ISC dhcpd configuration files into dcm.pl output to load into OpenNetAdmin

dhcpparse.awk

#!/usr/bin/awk -f
#
# Author: Matt Pascoe - [email protected]
#
# This awk script is used to extract relavant information from a dhcpd.conf
# config file and build dcm.pl output with appropriate fields.  This can be
# used to bootstrap a new database from existing site data.
# As usual, inspect the output for accuracy.
# Also you will get three types of output, subnet,pool,host.  You must
# add the subnet information first, then pool, then host.

# Note that for hosts, it will try a reverse lookup on the IP address
# to determine an appropriate dns name
#
# USAGE:
# make this script executable with `chmod +x dhcpparse.awk` and then
#
#   cat dhcpd.conf|./dhcpparse.awk|sort




# set the RECORD SEPARATOR, RS, to "}" ... records span multiple lines
BEGIN {RS="}"}

# TODO: figure out how to skip comment lines without having to use sed first

length($0) > 5 { total++

  for(i=1;i<=NF;i++) {

    counter[total] = total

    # if this field matches the word "host"
    if($i ~ /^host$/) {
      type[total] = "host"
      hostname[total]=$(i+1)
      # Remove the trailing { that might be there
      gsub(/{/, "", hostname[total])
    }

    # if this field matches the word "hardware"
    else if($i ~ /^hardware$/) {

      # get rid of the trailing semi-colon
      split($(i+2),arr,";")

      mac[total]=arr[1]
    }

    # if this field matches the word "hardware"
    else if($i ~ /^fixed-address$/) {

      # get rid of the trailing semi-colon
      split($(i+1),arr,";")

      ip[total]=arr[1]
    }

    # if this field matches the word "subnet"
    else if($i ~ /^subnet$/) {

      type[total] = "subnet"
      # get rid of the enclosing quotes
      split($(i+1),arr,"\"")

      subnetip[total]=arr[1]
    }

    # if this field matches the word "netmask"
    else if($i ~ /^netmask$/) {

      subnetmask[total]=$(i+1)
    }

    # if this field matches the word "range"
    else if($i ~ /^range$/) {
      total++
      type[total] = "pool"
      poolstart[total]=$(i+1)
      # get rid of the trailing semi-colon
      split($(i+2),arr,";")
      poolend[total]=arr[1]
    }

    # if this field matches the word "failover"
    if($i ~ /^#failover$/) {
      # get rid of the enclosing quotes
      split($(i+2),arr,"\"")

      failover[total]=arr[2]
    }
  }



  # do a host command reverse lookup on the IP to try and find a dns name
  if( length(ip[total]) > 0 ) {
    command = ("host " ip[total])
    command | getline tmpname
    close(command)
    split(tmpname,n,"pointer")

    # trim off leading spaces etc
    gsub(/^[ \t]+/, "", n[2])

    name[total] = substr(n[2],0,length(n[2])-1)
  }

  if( length(name[total]) == 0 ) {
    gsub(/\./, "-", hostname[total])
    # This option turns the ip into a fake name
    #name[total]="dhcpload-" ip[total]

    # This option just uses the text found in the conf for host
    name[total]=hostname[total]
  }


}

# for every entry we captured, display its appropriate info
END { for(entry in counter) {
         if(type[entry] == "subnet") {
             printf("dcm.pl -r %s_add ip=%s netmask=%s name='DHCPLOAD-%s' type='LAN'\n",\
                 type[entry],subnetip[entry],subnetmask[entry],subnetip[entry])
         }
         if(type[entry] == "pool") {
             printf("dcm.pl -r dhcp_pool_add start=%s end=%s\n",\
                 poolstart[entry],poolend[entry])
         }
         if(type[entry] == "host") {
             printf("dcm.pl -r %s_add ip=%s mac=%s host=%s type='Unknown, Unknown (Manually loaded)'\n",\
                 type[entry],ip[entry],mac[entry],name[entry])
         }
    }
}

My latest update now outputs direct dcm.pl command output instead of csv. There are goods and bads of both but the dcm.pl output seemed the most direct and simple for new users to understand and deal with. I also am defaulting hosts to the name field as defined in the dhcp.conf file. You can choose to switch to an IP mode here instead by adjusting comment lines at about line 112.

Thanks very much matt on the troubleshooting and line of though using the import script. Ill test up the parse update and give some feedback asap.

well, I managed to get the script running, but nothing appeared on the interface, besides the DHCP Pools. So I tried to run one line at a time to troubleshoot where it stopped. After adding the pools, on the first host it prompts the syntaxe, maybe its something wrong on the host_add line:

dcm.pl -r host_add ip=20.14.11.11 mac=00:22:71:69:85:40 name=AP01_AD2_S11

host_add-v1.11
Add a new host

  Synopsis: host_add [KEY=VALUE] ...

  Required:
    host=NAME[.DOMAIN]        Hostname for new DNS record
    type=TYPE or ID           Device/model type or ID
    ip=ADDRESS                IP address (numeric or dotted)

  Optional:
    notes=NOTES               Textual notes
    location=REF              Reference of location
    device=NAME|ID            The device this host is associated with

  Optional, add an interface too:
    mac=ADDRESS               Mac address (most formats are ok)
    name=NAME                 Interface name (i.e. "FastEthernet0/1.100")
    description=TEXT          Brief description of the interface
    addptr=Y|N                Auto add a PTR record for new host/IP (default: Y)