pydtls/dtls/test/echo_seq.py

122 lines
3.8 KiB
Python

# PyDTLS sequential echo.
# Copyright 2012 Ray Brown
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# The License is also distributed with this work in the file named "LICENSE."
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""PyDTLS sequential echo
This script runs a sequential echo server. It is sequential in that it will
respond without error only to a single sclient that invokes the following steps
in order:
* DTLS cookie exchange on port 28000 of localhost
* DTLS handshake (application-default ciphers)
* Write and receive echo back for an arbitrary number of datagrams
* Isue shutdown notification and receive the shutdown notification response
Note that this script's operation is slow and inefficient on purpose: it
invokes the demux without socket select, but with 5-second timeouts after
the cookie exchange; this is done so that one can follow the debug logs when
operating this server from a client shell interactively.
"""
import socket
from os import path
from logging import basicConfig, DEBUG
basicConfig(level=DEBUG) # set now for dtls import code
from dtls.sslconnection import SSLConnection
from dtls.err import SSLError, SSL_ERROR_WANT_READ, SSL_ERROR_ZERO_RETURN
def main():
sck = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sck.bind(("127.0.0.1", 28000))
sck.settimeout(30)
cert_path = path.join(path.abspath(path.dirname(__file__)), "certs")
scn = SSLConnection(
sck,
keyfile=path.join(cert_path, "keycert.pem"),
certfile=path.join(cert_path, "keycert.pem"),
server_side=True,
ca_certs=path.join(cert_path, "ca-cert.pem"),
do_handshake_on_connect=False)
cnt = 0
while True:
cnt += 1
print("Listen invocation: %d" % cnt)
peer_address = scn.listen()
if peer_address:
print("Completed listening for peer: %s" % str(peer_address))
break
print("Accepting...")
conn = scn.accept()[0]
sck.settimeout(5)
conn.get_socket(True).settimeout(5)
cnt = 0
while True:
cnt += 1
print("Listen invocation: %d" % cnt)
peer_address = scn.listen()
assert not peer_address
print("Handshake invocation: %d" % cnt)
try:
conn.do_handshake()
except SSLError as err:
if err.errno == 504:
continue
raise
print("Completed handshaking with peer")
break
cnt = 0
while True:
cnt += 1
print("Listen invocation: %d" % cnt)
peer_address = scn.listen()
assert not peer_address
print("Read invocation: %d" % cnt)
try:
message = conn.read()
except SSLError as err:
if err.errno == 502:
continue
if err.args[0] == SSL_ERROR_ZERO_RETURN:
break
raise
print(message)
conn.write("Back to you: " + message)
cnt = 0
while True:
cnt += 1
print("Listen invocation: %d" % cnt)
peer_address = scn.listen()
assert not peer_address
print("Shutdown invocation: %d" % cnt)
try:
s = conn.shutdown()
s.shutdown(socket.SHUT_RDWR)
except SSLError as err:
if err.errno == 502:
continue
raise
break
if __name__ == "__main__":
main()