if ICMP in pkt:

if pkt.getlayer(ICMP).type == 3 and pkt.getlayer(ICMP).code == 3:

return 'Status: Closed Reason: ICMP port unreachable (type: 3, code: 3)'

if pkt.getlayer(ICMP).type == 3:

return 'Status: Closed Reason: ICMP unreachable (type: 3, code: other)'

elif DNS in pkt:

return 'Status: Open Reason: Received DNS Response'

elif UDP in pkt:

return 'Status: Open Reason: Received UDP Response'

else:

parser = argparse.ArgumentParser(description='Port Scanner')

parser.add_argument('--version', action='version', version='%(prog)s 1.0',

help='Show Program\'s Version Number and Exit')

parser.add_argument('--target', help='Hostname or IP to scan', default='google.com')

parser.add_argument('--port', help='Port [X] or Port Range [X-Y] to scan', default='0-1023')

group = parser.add_mutually_exclusive_group()

group.add_argument('--tcp', action="store_true", help='TCP port scan (mutually exclusive with --udp)', default=True)

group.add_argument('--udp', action="store_true", help='UDP port scan (mutually exclusive with --tcp)')

parser.add_argument('--verbose', action="store_true", help='Verbose output (Print all ports, not just open ports)')

args, scan_list, port_range, dns = parser.parse_args(), dict(), list(), False

try:

# Check if port range is valid

port_range = [int(i) if 0 <= int(i) <= 65535 else int('e') for i in

args.port.split('-')] if '-' in args.port else [int(args.port)] if 0 <= int(

args.port) <= 65535 else int('e')

# Check if exactly two numbers are provided for the range such that the first is lesser than the second

int('e') if len(port_range) == 1 or len(port_range) == 2 and port_range[0] > port_range[1] or len(port_range) > 2 else 0

# Set protocol

proto = 'udp' if args.udp else 'tcp'

# Add all port numbers to a list and randomly shuffle if the port range is valid

port_range = list(range(port_range[0], port_range[1] + 1))

random.shuffle(port_range)

org_range = port_range.copy()

except ValueError:

sys.exit('ERROR: Invalid Port or Port Range')

# If user inputs IP Address, hostname is identified, otherwise IP address is identified

try:

if args.target[0].isdigit():

target_ip, target_hostname = args.target, socket.gethostbyaddr(args.target)[0]

else:

target_ip = socket.gethostbyname(args.target)

target_hostname = socket.gethostbyaddr(target_ip)[0]

except (socket.gaierror, socket.herror):

sys.exit('Error: Invalid hostname or IP address')

print(f'Scan type: {proto}\nTarget: {target_hostname} ({target_ip})\nPort(s): {args.port}')

# TCP Scan

if proto == 'tcp':

print('TCP Scanning....')

# Create IP/TCP packet and send/receive

ans, unans = sr(IP(dst=target_ip) / TCP(sport=22434, dport=port_range), verbose=0, timeout=5)

# Check if port is open by checking for SYN-ACK packet. If it's not present, port is closed.

for s, r in ans:

scan_list[r.sport] = 'Status: Open Reason: Received TCP SYN-ACK' if r.getlayer(

TCP).flags == 'SA' else 'Status: Closed Reason: Received TCP RST'

for s in unans:

scan_list[s.dport] = 'Status: Filtered Reason: No response'

# UDP Scan

else:

print('UDP Scanning....')

# Send a valid query only to port 53 and remove port 53 from the port_range list

if 53 in port_range:

port_range.remove(53)

ans, unans = sr(IP(dst=target_ip) / UDP(sport=22434, dport=53) / DNS(qd=DNSQR(qname="www.apple.com")),

verbose=0, timeout=5)

if len(ans) > 0:

for s, r in ans:

scan_list[r.sport] = udp_state(r)

else:

for s in unans:

scan_list[s.dport] = 'Status: Open|Filtered Reason: No response'

# Send a dummy text message to all ports other than port 53

ans, unans = sr(IP(dst=target_ip) / UDP(sport=22434, dport=port_range) / Raw('Hello World'), verbose=0,

timeout=5)

for s, r in ans:

scan_list[r.sport] = udp_state(r)

for s in unans:

scan_list[s.dport] = 'Status: Open|Filtered Reason: No response'

# Print the output of the scan in sorted order

for i in sorted(org_range):

print(f'Port: {i}' + ' ' * 5 + scan_list[i]) if args.verbose else print(