ipv6 python sockets not working ! OSError: [Errno 22] Invalid argument

Question

I have a simple client server program and the server side works but for some reason I can't get the the client to interact to the server. I am able to launch the server and use nc -6 fe80::cbdd:d3da:5194:99be%eth1 2020 and connect to it.

Server code:

    #!/usr/bin/env python3
from socket import *
from time import ctime

HOST='::'
PORT = 2020
BUFSIZ = 1024
ADDR = (HOST, PORT)

tcpSerSock = socket(AF_INET6, SOCK_STREAM)
##tcpSerSock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)

tcpSerSock.bind(ADDR)
tcpSerSock.listen(5)

while True:
        print('Waiting for connection...')

        tcpCliSock, addr = tcpSerSock.accept()
        print('...connected from:', addr)

        while True:
                data = tcpCliSock.recv(BUFSIZ)
                if not data:
                        break
                tcpCliSock.send(('[%s] %s'%(bytes(ctime(), 'utf-8'), data)).encode('utf-8'))
        tcpCliSock.close()
tcpSerSock.close()

client code:

    #!/usr/bin/python3
from socket import *





def tcp_ipv6():
    HOST = 'fe80::cbdd:d3da:5194:99be%eth1'
    PORT = 2020
    ADDR = (HOST, PORT)
    BUFSIZ = 1024
    
    sock = socket(AF_INET6, SOCK_STREAM)
    sock.connect(ADDR)
    
    while True:
        data = input('> ')
        if not data:
            break
        sock.send(data)
        response = sock.recv(BUFSIZ)
        if not response:
            break
        print(response.decode('utf-8'))
    sock.close()        
   
tcp_ipv6() 

When I run the client code I get:

Traceback (most recent call last):
  File "client.py", line 44, in <module>
    tcp_ipv6() 
  File "client.py", line 31, in tcp_ipv6
    sock.connect(ADDR)
OSError: [Errno 22] Invalid argument

Edit1: Thanks to Establishing an IPv6 connection using sockets in python 4-tuple for AF_INET6

ADDR = (HOST, PORT, 0, 0)
sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
sock.connect(ADDR)

Still having the same error

Any idea? Thanks in advance

Answer 1

The higher level function - create_connection , to connect to port works in such case. Sample scriptlet is given as follows. Though why sock.connect fails needs to be identified.

HOST = "xxxx::xxx:xxxx:xxxx:xxxx%en0"
PORT = 2020
ADDR = (HOST, PORT)
BUFSIZ = 1024

sock=create_connection(ADDR)