Initial revision
diff --git a/Demo/sockets/udpecho.py b/Demo/sockets/udpecho.py
new file mode 100755
index 0000000..53dff64
--- /dev/null
+++ b/Demo/sockets/udpecho.py
@@ -0,0 +1,63 @@
+#! /usr/local/python
+
+# Client and server for udp (datagram) echo.
+#
+# Usage: udpecho -s [port] (to start a server)
+# or: udpecho -c host [port] <file (client)
+
+import sys
+from socket import *
+
+ECHO_PORT = 50000 + 7
+BUFSIZE = 1024
+
+def main():
+ if len(sys.argv) < 2:
+ usage()
+ if sys.argv[1] = '-s':
+ server()
+ elif sys.argv[1] = '-c':
+ client()
+ else:
+ usage()
+
+def usage():
+ sys.stdout = sys.stderr
+ print 'Usage: udpecho -s [port] (server)'
+ print 'or: udpecho -c host [port] <file (client)'
+ sys.exit(2)
+
+def server():
+ if len(sys.argv) > 2:
+ port = eval(sys.argv[2])
+ else:
+ port = ECHO_PORT
+ s = socket(AF_INET, SOCK_DGRAM)
+ s.bind('', port)
+ print 'udp echo server ready'
+ while 1:
+ data, addr = s.recvfrom(BUFSIZE)
+ print 'server received', `data`, 'from', `addr`
+ s.sendto(data, addr)
+
+def client():
+ if len(sys.argv) < 3:
+ usage()
+ host = sys.argv[2]
+ if len(sys.argv) > 3:
+ port = eval(sys.argv[3])
+ else:
+ port = ECHO_PORT
+ addr = host, port
+ s = socket(AF_INET, SOCK_DGRAM)
+ s.bind('', 0)
+ print 'udp echo client ready, reading stdin'
+ while 1:
+ line = sys.stdin.readline()
+ if not line:
+ break
+ s.sendto(line, addr)
+ data, fromaddr = s.recvfrom(BUFSIZE)
+ print 'client received', `data`, 'from', `fromaddr`
+
+main()