added rcv buffer test

rcv_buffer/README

+The goal of this is to create a connected
+socket and NOT read data from it. The
+server will just send random bits into
+the socket to fill the receive buffer.
+We can then observe the receive buffer
+shrinking until it reaches zero. Then we
+will see how the server side continues.
+
+Alan Marchiori
+2019

rcv_buffer/randsender.py

+"""Ranodm data sender
+This server accepts TCP connections and
+send random data forever.
+
+Alan Marchiori
+2019
+"""
+import logging
+import socket
+import time
+import threading # to get thread name
+import argparse
+import os
+
+def handle_client(clientskt, clientaddr, log, bytelen=128, rate=10):
+    "handle a single client"
+
+    totalbytes = 0
+    log.info("Connection from {}".format(clientaddr))
+    try:
+        while True:
+
+
+            try:
+                sentbytes = clientskt.send(os.urandom(bytelen))
+
+                log.info("Sending... Sent {} of {} bytes to {}, total bytes = {}".format(
+                    sentbytes, bytelen, clientaddr, totalbytes))
+
+                totalbytes += sentbytes
+                time.sleep(1/rate)
+
+            except (BrokenPipeError, ConnectionResetError):
+                log.info("Client {} closed connection".format(clientaddr))
+                clientskt.close()
+                break
+            except socket.error as x:
+                log.info("Got {}, done with client.", x)
+                break
+    finally:
+        try:
+            clientskt.close()
+        except:
+            pass
+
+
+def main(addr, port):
+    log = logging.getLogger()
+    server_port = (addr, port)
+    log.info("[{}] Starting threading server on {}".format(
+        threading.current_thread().name, server_port))
+
+    threads = []
+
+    try:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as skt:
+            skt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            skt.bind(server_port) # bind socket to the UDP port
+            skt.listen()
+
+            while True:
+                clientskt, clientaddr = skt.accept()
+
+                t = threading.Thread(
+                    target=handle_client,
+                    args=(clientskt, clientaddr, log))
+                t.start()
+                threads.append((t, clientskt))
+
+    except KeyboardInterrupt:
+
+        for t, cskt in threads:
+            if t.is_alive():
+                cskt.close()
+
+
+
+if __name__ == "__main__":
+    FORMAT = '%(asctime)-15s %(levelname)-6s: %(message)s'
+    logging.basicConfig(format=FORMAT, level=logging.DEBUG)
+
+    parser = argparse.ArgumentParser(
+            description=__doc__)
+    parser.add_argument(
+        '-a', '--addr', type=str,
+        help='ip address of the server', required=False,
+        default="127.0.0.1")
+    parser.add_argument(
+        '-p', '--port', type=int,
+        help='port the server listens on', required=False,
+        default=8888)
+    args = parser.parse_args()
+    main(**vars(args))

rcv_buffer/zerorecv.py

+"""Ranodm data sender
+This server accepts TCP connections and
+send random data forever.
+
+Alan Marchiori
+2019
+"""
+import logging
+import socket
+import time
+import argparse
+import os
+
+
+def main(addr, port):
+    log = logging.getLogger()
+    server_port = (addr, port)
+    log.info("Starting client, connect to {}".format(
+        server_port))
+
+
+    try:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as skt:
+
+            skt.connect(server_port)
+
+            log.info("Connected to {}. Doing nothing!".format(server_port))
+            while True:
+                time.sleep(0.1)
+
+    except KeyboardInterrupt:
+
+        log.info("ctrl-c, quit!")
+
+
+
+if __name__ == "__main__":
+    FORMAT = '%(asctime)-15s %(levelname)-6s: %(message)s'
+    logging.basicConfig(format=FORMAT, level=logging.DEBUG)
+
+    parser = argparse.ArgumentParser(
+            description=__doc__)
+    parser.add_argument(
+        '-a', '--addr', type=str,
+        help='ip address of the server', required=False,
+        default="127.0.0.1")
+    parser.add_argument(
+        '-p', '--port', type=int,
+        help='port the server listens on', required=False,
+        default=8888)
+    args = parser.parse_args()
+    main(**vars(args))

socket_examples/udp_client.py

@@ -22,9 +22,9 @@ print ("message:", MESSAGE)
 with socket.socket(socket.AF_INET, # Internet
                      socket.SOCK_DGRAM) as sock: # UDP
 
-    #sock.bind((UDP_IP, 8889))
+    sock.bind((UDP_IP, 8889))
     print("Socket:", sock)
     sock.sendto(MESSAGE, (UDP_IP, UDP_PORT))
-    #print("Socket:", sock)
+    print("Socket:", sock)
     #sock.sendto(MESSAGE, (UDP_IP, UDP_PORT))
     #print("Socket:", sock)