commit 1a2a19c7fa4228c76356520026a3a4d9f61e0f56
Author: Ben Charlton <ben@spod.cx>
Date:   Mon Jan 6 23:13:46 2025 +0000

    initial release

diff --git a/uniqcidr.py b/uniqcidr.py
new file mode 100755
index 0000000..16ca43e
--- /dev/null
+++ b/uniqcidr.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+
+import ipaddress
+import sys
+import argparse
+
+# Default to /32 and /128 for single IP addresses
+start_v4 = 32
+start_v6 = 128
+
+parser = argparse.ArgumentParser(
+                    prog='uniqcidr',
+                    description='Like uniq, but understands CIDR netmasks',
+                    epilog='...but written by an idiot')
+
+parser.add_argument('-c', '--count', action='store_true', help="count number of IPs occurring in each subnet")
+parser.add_argument('-n', '--network', action='store_true', help="Enable network mode, don't require contiguous IP addresses. Sets /48 and /24 thresholds")
+parser.add_argument('-6', '--v6netmask', type=int, help=f'IPv6 netmask, default: {start_v6}') 
+parser.add_argument('-4', '--v4netmask', type=int, help=f'IPv4 netmask, default: {start_v4}') 
+
+args = parser.parse_args()
+
+# Network mode counts every /24 or /48 
+if args.network:
+    start_v4 = 24
+    start_v6 = 48
+
+# Custom subnet thresholds. -6 64 is probably the othe most useful here.
+if args.v6netmask:
+    start_v6 = args.v6netmask
+if args.v4netmask:
+    start_v4 = args.v4netmask
+
+def render_line(count, curr_network):
+    if args.count:
+        print(f"{count:>5} {curr_network}")
+    else:
+        print(curr_network)
+
+curr_network = None
+count = 0
+for line in sys.stdin:
+
+    line = line.rstrip()
+    try:
+        ifa = ipaddress.ip_interface(line)
+    except ValueError:
+        print(f"Not an ip address: {line}", file=sys.stderr)
+        continue
+
+    prefix = start_v6
+    if ifa.version == 4:
+        prefix=start_v4
+
+    network = ifa.network.supernet(new_prefix=prefix)
+
+    if curr_network is None:
+        curr_network = network
+        continue
+
+    count = count + 1
+
+    if network.version != curr_network.version:
+        render_line(count, curr_network)
+        curr_network = network
+        count = 0
+
+    if curr_network != network:
+        if network.subnet_of(curr_network):
+            pass
+        elif network.subnet_of(curr_network.supernet()):
+            curr_network = curr_network.supernet()
+        else:
+            render_line(count, curr_network)
+            curr_network = network
+            count = 0
+
+count = count + 1
+render_line(count, curr_network)