Update prefix listing

get_prefixes.awk

@@ -0,0 +1,79 @@
+function print_prefix(prefix, count, status) {
+  printf "%-20s%-10s%s\n", prefix, count, status
+}
+
+function d2b(d, b) {
+  while(d) {
+    b=d%2b
+    d=int(d/2)
+  }
+  return b
+}
+
+function ip2dec(prefix) {
+  split(prefix, splitted_prefix, ".")
+  b1 = splitted_prefix[1] * 256^3
+  b2 = splitted_prefix[2] * 256^2
+  b3 = splitted_prefix[3] * 256
+  b4 = splitted_prefix[4]
+  return b1 + b2 + b3 + b4
+}
+
+function dec2ip(dec_prefix) {
+  b1 = int(dec_prefix/256^3) % 256
+  b2 = int(dec_prefix/256^2) % 256
+  b3 = int(dec_prefix/256) % 256
+  b4 = int(dec_prefix) % 256
+  return b1 "." b2 "." b3 "." b4
+}
+
+function compute_prefix(prefix, count, status, count_alloc) {
+  split(prefix, bytes, ".")
+
+  # Everything in 151.216.0.0/13 is reserved for temporary assignments
+  if(bytes[1] == 151 && bytes[2] >= 216 && bytes[2] <= 223) {
+    return 0
+  }
+
+  # Everything in 185.0.0.0/15 is reserved for IXP assignments
+  if(bytes[1] == 185 && bytes[2] <= 1) {
+    return 0
+  }
+
+  for(i = 4; i >= 0; i--) {
+    if(bytes[i] != 0) {
+      bin = d2b(bytes[i])
+      idx = match(bin, /0*$/)
+      host_bytes = 1 substr(bin, idx, 9 - idx)
+      split(host_bytes, msb, "")
+      max_count = 2^(length(msb) - 1) * 256 ^ (4 - i)
+      if(max_count > count) {
+        max_count = count
+      }
+      cidr = 32 - log(max_count)/log(2)
+      remainder = count - max_count
+      if(cidr <= 24) {
+        print_prefix(prefix "/" cidr, max_count, status)
+        count_alloc = count_alloc + 2^(24-cidr)
+      }
+
+      if(remainder > 0) {
+        new_prefix = dec2ip(ip2dec(prefix) + max_count)
+        count_alloc = count_alloc + compute_prefix(new_prefix, remainder, status, count_alloc)
+      }
+      return count_alloc
+    }
+  }
+}
+
+BEGIN {
+  FS = "|"
+  print_prefix("Prefix", "Addresses", "Status")
+  count_alloc = 0
+}
+$3 == "ipv4" && $7 ~ /(reserved|available)/ && $5 >= 256 {
+  count_alloc = compute_prefix($4, $5, $7, count_alloc)
+}
+END {
+  print "Number of /24 available for future allocation: " count_alloc
+}

get_prefixes.sh

@@ -1,6 +1,3 @@
 #!/usr/bin/env bash
 
-curl -s https://ftp.ripe.net/ripe/stats/delegated-ripencc-extended-latest | awk -F "|" '
+curl -s https://ftp.ripe.net/ripe/stats/delegated-ripencc-extended-latest | awk -f $(dirname -- "${BASH_SOURCE[0]}")/get_prefixes.awk > $(dirname -- "${BASH_SOURCE[0]}")/ipv4_available_reserved.txt
-$3 == "ipv4" && $7 ~ /(reserved|available)/ && $5 >= 256 {
-  printf "%-15s\t%i\t%s\n", $4, $5, $7
-}' > $(dirname -- "${BASH_SOURCE[0]}")/ipv4_available_reserved.txt