First upload

LICENSE

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+MIT License
+
+Copyright (c) 2023 Marco
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# subnet.py
+CLI tool to determine various information of a given IPv4 address in CIDR format.
+
+## Installation
+This program is written in Python using only the builtin libraries, you can move it
+wherever you like and invoke it from there.
+
+## Usage
+Run the program without any parameter, the helper will walk you through on how to use it.
+For example:
+
+```sh
+$> ./subnet.py 10.0.3.4/24
+IP Address: 10.0.3.4 (00001010 00000000 00000011 00000100)
+Subnet Mask: 255.255.255.0 (11111111 11111111 11111111 00000000)
+Network Prefix: 10.0.3.0 (00001010 00000000 00000011 00000000)
+Host Prefix: 0.0.0.4 (00000000 00000000 00000000 00000100)
+Usable Hosts: 254
+IP Class: A
+```

subnet.py

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+#!/usr/bin/env python3
+# CLI tool to determine various information
+# of a given IPv4 address in CIDR format
+# Developed by Marco Cetica (c) 2023 <email@marcocetica.com>
+#
+import sys
+import ipaddress
+
+class IP:
+    """Extract various information from an IPv4 in CIDR format"""
+    cidr: str = ""
+    ip_addr: str = ""
+    mask: str = ""
+    mask_bin: str = ""
+    network_prefix: str = ""
+    network_bin: str = ""
+    host_prefix: str = ""
+    host_bin: str = ""
+    usable_hosts: str = ""
+    ip_class: str = ""
+
+    def __init__(self, cidr):
+        # Check if CIDR is properly formatted
+        if '/' not in cidr:
+            raise ValueError("Invalid CIDR('xxx.xxx.xxx.xxx/xx')")
+
+        # Check if IP address is valid
+        ip_addr, mask = cidr.split('/')
+        octets = ip_addr.split('.')
+        if len(octets) != 4:
+            raise ValueError("Invalid IP address")
+
+        for v in octets:
+            if int(v) > 255 or int(v) < 0:
+                raise ValueError("IP address out of range")
+
+        # Check if subnet mask is in range
+        if int(mask) > 32 or int(mask) < 1:
+            raise ValueError("Subnet mask out of range")
+
+        # Otherwise set cidr
+        self.cidr = cidr
+
+    def extract_data(self) -> None:
+        # Get IP and subnet mask
+        self.ip_addr = self.cidr.split('/')[0]
+        self.mask = ipaddress.IPv4Network(self.cidr, strict=False).netmask
+
+        # Convert both of them to int
+        network = ipaddress.IPv4Network(self.ip_addr)
+        ip_addr_int = int(network.network_address)
+        mask_int = int(self.mask)
+
+        # Get network and host prefix
+        network_prefix_int = (ip_addr_int & mask_int)
+        host_prefix_int = (ip_addr_int & ~mask_int)
+
+        # Convert network and host prefix back to dot notation
+        self.network_prefix = str(ipaddress.IPv4Network(network_prefix_int)).split('/')[0]
+        self.host_prefix = str(ipaddress.IPv4Network(int(host_prefix_int))).split('/')[0]
+
+        # Get binary representation of ip address, mask and prefixes
+        self.ip_bin = ' '.join(format(int(x), '08b') for x in self.ip_addr.split('.'))
+        self.mask_bin = ' '.join(format(int(x), '08b') for x in str(self.mask).split('.'))
+        self.network_bin = ' '.join(format(int(x), '08b') for x in self.network_prefix.split('.'))
+        self.host_bin = ' '.join(format(int(x), '08b') for x in self.host_prefix.split('.'))
+
+        # Compute usable hosts
+        mask_complement = (~mask_int & (2 ** mask_int.bit_length() - 1))
+        bit_count = bin(mask_complement).count('1')
+        self.usable_hosts = (2 ** bit_count - 2) if bit_count > 0 else 0
+
+        # Get IP Class
+        first_octet = int(self.ip_addr.split('.')[0])
+        ip_classes = {
+            (0 < first_octet <= 127): 'A',
+            (128 <= first_octet <= 191): 'B',
+            (192 <= first_octet <= 223): 'C'
+        }
+        self.ip_class = next((val for cond, val in ip_classes.items() if cond), None)
+
+
+def main():
+    if len(sys.argv) < 2:
+        print(f"Usage {sys.argv[0]} <CIDR>")
+        sys.exit(1)
+
+    # Get the CIRD
+    cidr = sys.argv[1]
+
+    # Extract info from IP
+    try:
+        ip = IP(cidr)
+        ip.extract_data()
+        print(f"IP Address: {ip.ip_addr} ({ip.ip_bin})")
+        print(f"Subnet Mask: {ip.mask} ({ip.mask_bin})")
+        print(f"Network Prefix: {ip.network_prefix} ({ip.network_bin})")
+        print(f"Host Prefix: {ip.host_prefix} ({ip.host_bin})")
+        print(f"Usable Hosts: {ip.usable_hosts}")
+        print(f"IP Class: {ip.ip_class}")
+    except ValueError as e:
+        print(e)
+        sys.exit(1)
+
+if __name__ == "__main__":
+    main()