contrib: add first .awk algorithm test version to contrib

The script is not maintained, but perhaps nice to have a
reference how the IP sorting & range matching was done in demo
version. Actually more proper version number would have been 0.x
but it was not.

Signed-off-by: Sami Kerola <sami.kerola@tomtom.com>

contrib/dhcpd-pools.awk

@@ -0,0 +1,168 @@
+# This is ISC dhcpd pool statistics script.
+#
+# The script is first version which was used to test that
+# analysis algorithm is sane. This script is no longer
+# maintained, and can be considered as historic reference.
+#
+# Licensed under the Open Software License version 1.1
+# http://opensource.org/licenses/osl.php
+#
+# Sami Kerola <sami.kerola@teliasonera.com>
+#
+# Latest version is available from http://www.iki.fi/kerolasa/dhcp/
+# This is version 1.4
+
+BEGIN {
+    # Do you want to see statistics per pool? 1 = yes, 0 = no.
+    PrintRanges = 1
+
+    leasefile="/opt/dhcp/db/dhcpd.leases"
+    #conffile="/opt/dhcp/etc/dhcpd.conf"
+
+    # External commands.
+    uniq = "sort -nu > afterlp"
+    sort = "sort -nu -k 2 > aftercp"
+    uniqstdout = "sort -u"
+
+    # Do the trick.
+    main()
+}
+
+# Convert ip to decimal number.
+function ip2num(addr) {
+    split(addr, z, ".");
+    numb = z[4]+256*(z[3]+256*(z[2]+256*z[1]))
+    return numb
+}
+
+# Print decimal ip in dotted format.
+function printip(number) {
+    a = int(number/16777216)
+    number = (number-(a*16777216))
+    b = int(number/65536)
+    number = int((number-(b*65536)))
+    c = int(number/256)
+    number = (number-(c*256))
+    ipstring = sprintf("%d.%d.%d.%d", a, b, c, number)
+    printf "%16s", ipstring
+}
+
+# Parse dhcpd lease file.
+function parseleases() {
+    if (system("test -r " leasefile) != 0) {
+        print "File " leasefile " is not readable, exiting."
+        exit 1
+    }
+    while (getline < leasefile) {
+        if ($0 ~ /^lease/) {
+            A = ip2num($2)
+        }
+        if ($0 ~ /^[    ]*binding state active/) {
+            printf "%d\n", A | uniq
+        }
+    }
+    close(leasefile)
+    close(uniq)
+}
+
+# Parse dhcpd configuration file.
+function parseconf() {
+    while (getline) {  
+        if ($0 ~ /^[    ]*shared-network/) {
+            sharnet = $2
+        }
+        if ($0 ~ /^[    ]*range/) {
+            printf "%s %d %d\n", sharnet, ip2num($2), ip2num($3) | sort
+        }
+    }
+    close(sort)
+}
+
+# Join preparsed tmp files and output pool status.
+function join() {
+    # Get shared networks and pool ranges.
+    i = 1
+    while (getline < "aftercp") {
+        split($0, j, " ")
+        cnf[i,1] = j[1]
+        cnf[i,2] = j[2]
+        if (j[3] == 0) {
+            j[3] = j[2]
+        }
+        cnf[i,3] = j[3]
+        shnet[j[1],1] += j[3]-j[2]+1
+        shnet[j[1],2] = 0
+        allofall[1] += j[3]-j[2]+1
+        i++
+    }
+    close("aftercp")
+    i = 1
+    allofall[2] = k = 0
+    thisnet = ""
+    # Count IPs in pools.
+    if (PrintRanges) {
+        # Print header.
+        print "shared-network            1st in pool    last in pool   max   cur    usage%"
+    }
+    k = 0;
+    while (getline < "afterlp") {
+        ip = $0
+          allofall[2]++
+        # Ip out of the range, pool is changing.
+        while (ip > cnf[i,3]) {
+          if (PrintRanges) {
+              printf "%-20s ", cnf[i,1]
+              printip(cnf[i,2])
+              printip(cnf[i,3])
+              printf " %5d %5d %9.2f\n", cnf[i,3]-cnf[i,2]+1, k, k/(cnf[i,3]-cnf[i,2]+1)
+              k = 0;
+            }
+            if (cnf[i,1] != thisnet) {
+                # Shared network changed.
+                thisnet = cnf[i,1]
+            }
+            i++
+        }
+        if (ip > cnf[i,2] && ip < cnf[i,3]) {
+            # Add ip.
+            shnet[cnf[i,1],2]++
+        }
+        k++;
+    }
+ 
+    # Print pool statistics.
+
+
+    if (PrintRanges) {
+        printf "%-20s ", cnf[i,1]
+        printip(cnf[i,2])
+        printip(cnf[i,3])
+        printf " %5d %5d %9.2f\n", cnf[i,3]-cnf[i,2]+1, k, k/(cnf[i,3]-cnf[i,2]+1)
+    }
+    close("afterlp")
+    # Print header and shared network statistics.
+    print "#shared-network            max      cur   usage%"
+    for (items in shnet) {
+        x = substr(items, 1, length(items)-2)
+        printf "%-20s %8d %8d %8.4f\n", x, shnet[x,1], shnet[x,2], shnet[x,2]/shnet[x,1] | uniqstdout
+    }
+    close(uniqstdout)
+    print "#--------------"
+    printf "%-20s %8d %8d %8.4f\n", "all_pools", allofall[1], allofall[2], allofall[2]/allofall[1]
+}
+
+# Remove temporary files.
+function cleanup() {
+    system("rm -f aftercp afterlp")
+}
+
+# Main.
+function main() {
+    system("touch afterlp aftercp")
+    parseleases()
+    parseconf()
+    join()
+    cleanup()
+}
+
+# EOF