Topic: My Own DHCP Leases Server Panel

[rmclay]

Hi Guys,

I've cobbled together a quick and dirty active DHCP Leases script.  I've been using esmith-esi-lanlord on 6.x, but noticed the only version of this type of thing for SME 7.x was dhcpactiv.sh.  While this is a good script, I wanted to package my own script and create a server panel for it, as a lesson in coding.

So far I have the following script:

Code: [Select]

#!/bin/sh
##############################################################################
#         RMCLAY'S DHCP MANAGER        AN EXCERCISE IN SME 7.X CODING        #
##############################################################################
#                                                                            #
# v0.7 --- Almost done, also prints number of hours DHCP leases last.  Also  #
#          puts info into an html file using txt2html.                       #
# v0.6 --- Cleaner code, have started pulling hostname from dhcp.leases.     #
# v0.5 --- Now working out the ARP hostname & printing them to screen.       #
# v0.4 --- Printing a pretty table now.  Need to encode to table format.     #
# v0.2 --- Various sed & grep wiredness giving our output formatted, but no  #
#          table yet.                                                        #
#                                                                            #
# Done in stages, it's poor coding; but I need to understand it in 6 months. #
#                                                                            #
# TODO: replace 2008 with 08 (date +M), remove " from hostnames with sed, I  #
#       also need to make the html file into a server panel                  #
#                                                                            #
# Consider this script GPL V3                                                #
##############################################################################

# Read in the dhcp.conf file, and work out how long our leases last for
lease=`cat /etc/dhcpd.conf | grep default-lease | awk '{ print $2 }' | sed "s/;//g"`
sec=`echo $(($lease/3600))`

# Get current leases, remove the comments (### Blah) & put them on one line...
cat /var/lib/dhcp/dhcpd.leases | grep -v "#" | grep -v uid | grep -v bind | tr "{\n" '\t' | tr '}' '\n' > /tmp/tmp.$$

# clean the whitespace.  Make sure each line only has 1 space between columns
cat /tmp/tmp.$$ | tr '\t' ' ' | sed 's/^[ \t]*//;s/[ \t]*$//' > /tmp/tmp2.$$

# remove some text dhcpd likes, but we don't care for...
cat /tmp/tmp2.$$ | sed "s/starts//" | sed "s/ends//" | sed "s/hardware//" | sed "s/ethernet//" | sed "s/client-hostname//" | sed "s/tstp//" | tr ';' ' ' > /tmp/tmp.$$
cat /tmp/tmp.$$ | sed "s/ 0 //g" | sed "s/ 2 //g" | sed "s/ 3 //g" | sed "s/ 6 //g" | sed "s/lease//g" > /tmp/tmp3.$$
cat /tmp/tmp3.$$ | sed "s/   / /g" > /tmp/tmp2.$$

# show only the lines we want to see
cat /tmp/tmp2.$$ | awk '{ print $1" "$2" "$3" "$6" "$7 }' > /tmp/tmp3.$$

# Append the lease time in hrs to end of the info
rm /tmp/tmp.$$
while read info
 do
  echo "$info" "  $sec"hrs >> /tmp/tmp.$$
 done < /tmp/tmp3.$$

# Echo the header info into our leases list
echo > /tmp/test.$$
echo '[Current DHCP Leases:]' >> /tmp/test.$$
echo ':c' >> /tmp/test.$$
echo >> /tmp/test.$$
echo '[IP Address],[Hostname],[MAC Address],[Lease Obtained],[Lease Length]' >> /tmp/test.$$
cat /tmp/tmp.$$ | awk '{ printf "%-15s %-15s %-17s %-8s %-10s %-6s \n", $1, "," $5, "," $4, "," $2, " " $3, "," $NF }' > /tmp/tmp2.$$

# Sort the IP Addresses chronologically.  Then append to info text file
cat /tmp/tmp2.$$ | sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n | uniq -w 15 | grep hrs >> /tmp/test.$$

# This stuff enables txt2html to make a nice pretty table
echo ":tb" >> /tmp/test.$$

# Use txt2html to convert into a pretty table
txt2html /tmp/test.$$ > /tmp/rmclay_dhcpman.html

# clean up
rm /tmp/tmp.$$ /tmp/tmp2.$$ /tmp/tmp3.$$$ /tmp/test.$$


I admit my code is not the best   But what I am hoping to do is the following:

1.) Add the hostname to this list

2.) Create a server manager panel.  In order to do this, can I simply pipe the output of my script into a text file and display that in a server manager panel...?

Thanks,
Robert

[gzartman]

I admit my code is not the best   But what I am hoping to do is the following:

1.) Add the hostname to this list

I'm sure there many ways to do this.  dig -x ip_address will return the hostname. 

2.) Create a server manager panel.  In order to do this, can I simply pipe the output of my script into a text file and display that in a server manager panel...?

No, it is not that simple.  server-manager panels are somewhat complex to create, especially if it is your first panel.  Expect to spend at least half a dozen hrs on your first effort at creating a server-manager panel.

You are basically wanting to report information in "friendly" format.  This, in and of itself, does not really warrant the effort to create a panel.   I believe you could achieve the same goal with a properly formatted log file placed in /var/log.  You could then use the View log files server-manager panel to view your DHCP IP lease log file.

Greg 

[FraunhoferIFF]

Code: [Select]

#!/bin/sh
#
# dhcpactiv.sh
#
# v.004
# - rewritten again to pull data from dhcpd files according to labels instead of position
#
# v.003
# - add code to remove tstp information from dpcpd.leases
#
# v.002
# - rewritten to use awk more for parsing
# - added "GMT" indicator to Expiration col head
#
echo "Source        Host       MAC Address       IP Address      Expiration (GMT)"
echo "============= ========== ================= =============== ================"
#
awk ' { out = ""} \
      { $1=="lease"||$1=="client-hostname" ? out=" " $2 : out=out } \
      { $1=="binding"||$1=="hardware" ? out= " " $3: out=out } \
      { $1=="ends"? out=" " $3 " " $4: out=out } \
      { $1=="}"? out="\n": out=out } \
      { printf out," " }' /var/lib/dhcp/dhcpd.leases \
  | grep active \
  | sed -e s/'[{};" ]'/\ /g  \
  | awk '{ printf "%-13s %-10s %-17s %-15s %-10s %-5s\n", "dhcpd.leases", $6, $5, $1, $2, $3 }'

#
# Now do the same for /etc/dhcpd.conf
#
 awk ' { out = ""}
       { $1=="host"||$1=="fixed-address" ? out=" " $2 : out=out } \
       { $1=="hardware" ? out= " " $3: out=out } \
       { $1=="}"? out="\n": out=out } \
       { printf out," " }' /etc/dhcpd.conf \
  | grep : \
  | sed -e  s/'[{};\" ]'/\ /g -e  s/\.`config get DomainName`// \
  | awk  '{ printf "%-13s %-10s %-17s %-15s %-15s \n", "dhcpd.conf", $1, $2, $3, "reservation"}'
#
# Finally, grab the current arp table
#
arp -a \
  |  sed -e s/\\..*\(/\ / -e s/\)// \
  |  awk '{ printf "%-13s %-10s %-17s %-15s %-15s \n", "arp", $1, $4, $2, "n/a"}'

save as dhcpaktiv.sh
chmod 775

Marcel

[rmclay]

Hi Marcel,

I have previously used the dhcpactive script to append current leases to the log files with no problem.  Although as mentioned in my first message, I want to have a go at creating a server panel.  While this is overkill for such a small function; I also want to expand my knowledge of SME Server.

As things stand now, I have a script reporting in HTML format (you will need to download the txt2html source and compile form here: http://www.cs.sandia.gov/~sjplimp/download.html Then move your txt2html binary to /usr/local/bin (I will package up a contrib once everything is working...)

I have another question:  Is it possible to display this static html page in the server manager without having to encode everything in XML...?  If not, can someone perhaps help me with turning this into a contrib...?

Thanks again,
Robert

[janet]

rmclay

The Developer Guide (ie Manual) gives an introduction to creating web panels in a simple step by step example. Click Wiki at the top of the Forums.

Read the code for other panels for more advanced functionality & how to do it.
You can even copy the code for the nearest closest panel functionality and modify to suit.

If you want specific help to create a contrib, then open a bug report for a new Contrib, and ask for help there. Developers will want justification for the project though before they commit too much resources.