Cleanup URI code and TCP bugfixing

- Add CLI/API to enable session layer, by default it's disabled
- Improve rcv wnd computation
- Improvements to tx path
- URI code cleanup
- Builtin test tcp server
- Improve src port allocation

Change-Id: I2ace498e76a0771d4c31a8075cc14fe33d7dfa38
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/scripts/vnet/uri/dummy_app.py b/src/scripts/vnet/uri/dummy_app.py
new file mode 100644
index 0000000..b80fbb2
--- /dev/null
+++ b/src/scripts/vnet/uri/dummy_app.py
@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+
+import socket
+import sys
+import bitstring
+
+# action can be reflect or drop 
+action = "drop"
+
+def handle_connection (connection, client_address):
+    print("Received connection from {}".format(repr(client_address)))
+    try:
+        while True:
+            data = connection.recv(4096)
+            if not data:
+                break;
+            if (action != "drop"):
+                connection.sendall(data)
+    finally:
+        connection.close()
+        
+def run_server(ip, port):
+    print("Starting server {}:{}".format(repr(ip), repr(port)))
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    server_address = (ip, int(port))
+    sock.bind(server_address)
+    sock.listen(1)
+    
+    while True:
+        connection, client_address = sock.accept()
+        handle_connection (connection, client_address)
+
+def prepare_data():
+    buf = []
+    for i in range (0, pow(2, 16)):
+        buf.append(i & 0xff)
+    return bytearray(buf)
+
+def run_client(ip, port):
+    print("Starting client {}:{}".format(repr(ip), repr(port)))
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    server_address = ("6.0.1.1", 1234)
+    sock.connect(server_address)
+    
+    data = prepare_data()
+    try:
+        sock.sendall(data)
+    finally:
+        sock.close()
+    
+def run(mode, ip, port):
+    if (mode == "server"):
+        run_server (ip, port)
+    elif (mode == "client"):
+        run_client (ip, port)
+    else:
+        raise Exception("Unknown mode. Only client and server supported")
+
+if __name__ == "__main__":
+    if (len(sys.argv)) < 4:
+        raise Exception("Usage: ./dummy_app <mode> <ip> <port> [<action>]")
+    if (len(sys.argv) == 5):
+        action = sys.argv[4]
+
+    run (sys.argv[1], sys.argv[2], sys.argv[3])
diff --git a/src/scripts/vnet/uri/tcp_server b/src/scripts/vnet/uri/tcp_server
index 7f5a86d..c29afc6 100644
--- a/src/scripts/vnet/uri/tcp_server
+++ b/src/scripts/vnet/uri/tcp_server
@@ -2,3 +2,4 @@
 set int state host-vpp1 up
 set int ip address host-vpp1 6.0.1.1/24
 trace add af-packet-input 10
+session enable