lwip - Added udp_dtls_handshake test

Added test for the pattern of packets used during the DTLS
handshake. This pattern (5x ~300 byte packets) has been very
problematic for new network interfaces.

features/FEATURE_LWIP/TESTS/mbedmicro-net/host_tests/udp_shotgun.py

@@ -0,0 +1,135 @@
+"""
+mbed SDK
+Copyright (c) 2011-2013 ARM Limited
+
+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
+
+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.
+"""
+
+import sys
+import socket
+import json
+import random
+import itertools
+from sys import stdout
+from threading import Thread
+from SocketServer import BaseRequestHandler, UDPServer
+from mbed_host_tests import BaseHostTest, event_callback
+
+
+class UDPEchoClientHandler(BaseRequestHandler):
+    def handle(self):
+        """ UDP packet handler. Responds with multiple simultaneous packets
+        """
+        data, sock = self.request
+        pattern = [ord(d) << 4 for d in data]
+
+        # Each byte in request indicates size of packet to recieve
+        # Each packet size is shifted over by 4 to fit in a byte, which
+        # avoids any issues with endianess or decoding
+        for packet in pattern:
+            data = [random.randint(0, 255) for _ in range(packet-1)]
+            data.append(reduce(lambda a,b: a^b, data))
+            data = ''.join(map(chr, data))
+            sock.sendto(data, self.client_address)
+
+
+class UDPEchoClientTest(BaseHostTest):
+    def __init__(self):
+        """
+        Initialise test parameters.
+
+        :return:
+        """
+        BaseHostTest.__init__(self)
+        self.SERVER_IP = None # Will be determined after knowing the target IP
+        self.SERVER_PORT = 0  # Let TCPServer choose an arbitrary port
+        self.server = None
+        self.server_thread = None
+        self.target_ip = None
+
+    @staticmethod
+    def find_interface_to_target_addr(target_ip):
+        """
+        Finds IP address of the interface through which it is connected to the target.
+
+        :return:
+        """
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.connect((target_ip, 0)) # Target IP, Any port
+        ip = s.getsockname()[0]
+        s.close()
+        return ip
+
+    def setup_udp_server(self):
+        """
+        sets up a UDP server for target to connect and send test data.
+
+        :return:
+        """
+        # !NOTE: There should mechanism to assert in the host test
+        if self.SERVER_IP is None:
+            self.log("setup_udp_server() called before determining server IP!")
+            self.notify_complete(False)
+
+        # Returning none will suppress host test from printing success code
+        self.server = UDPServer((self.SERVER_IP, self.SERVER_PORT), UDPEchoClientHandler)
+        ip, port = self.server.server_address
+        self.SERVER_PORT = port
+        self.server.allow_reuse_address = True
+        self.log("HOST: Listening for UDP packets: " + self.SERVER_IP + ":" + str(self.SERVER_PORT))
+        self.server_thread = Thread(target=UDPEchoClientTest.server_thread_func, args=(self,))
+        self.server_thread.start()
+
+    @staticmethod
+    def server_thread_func(this):
+        """
+        Thread function to run TCP server forever.
+
+        :param this:
+        :return:
+        """
+        this.server.serve_forever()
+
+    @event_callback("target_ip")
+    def _callback_target_ip(self, key, value, timestamp):
+        """
+        Callback to handle reception of target's IP address.
+
+        :param key:
+        :param value:
+        :param timestamp:
+        :return:
+        """
+        self.target_ip = value
+        self.SERVER_IP = self.find_interface_to_target_addr(self.target_ip)
+        self.setup_udp_server()
+
+    @event_callback("host_ip")
+    def _callback_host_ip(self, key, value, timestamp):
+        """
+        Callback for request for host IP Addr
+
+        """
+        self.send_kv("host_ip", self.SERVER_IP)
+
+    @event_callback("host_port")
+    def _callback_host_port(self, key, value, timestamp):
+        """
+        Callback for request for host port
+        """
+        self.send_kv("host_port", self.SERVER_PORT)
+
+    def teardown(self):
+        if self.server:
+            self.server.shutdown()
+            self.server_thread.join()

features/FEATURE_LWIP/TESTS/mbedmicro-net/udp_dtls_handshake/main.cpp

@@ -0,0 +1,123 @@
+#if !FEATURE_LWIP
+    #error [NOT_SUPPORTED] LWIP not supported for this target
+#endif
+
+#include "mbed.h"
+#include "EthernetInterface.h"
+#include "UDPSocket.h"
+#include "greentea-client/test_env.h"
+#include "unity/unity.h"
+
+#ifndef MBED_CFG_UDP_DTLS_HANDSHAKE_BUFFER_SIZE
+#define MBED_CFG_UDP_DTLS_HANDSHAKE_BUFFER_SIZE 512
+#endif
+
+#ifndef MBED_CFG_UDP_DTLS_HANDSHAKE_RETRIES
+#define MBED_CFG_UDP_DTLS_HANDSHAKE_RETRIES 16
+#endif
+
+#ifndef MBED_CFG_UDP_DTLS_HANDSHAKE_PATTERN
+#define MBED_CFG_UDP_DTLS_HANDSHAKE_PATTERN 112, 384, 200, 219, 25
+#endif
+
+uint8_t buffer[MBED_CFG_UDP_DTLS_HANDSHAKE_BUFFER_SIZE] = {0};
+int udp_dtls_handshake_pattern[] = {MBED_CFG_UDP_DTLS_HANDSHAKE_PATTERN};
+const int udp_dtls_handshake_count = sizeof(udp_dtls_handshake_pattern) / sizeof(int);
+
+int main() {
+    GREENTEA_SETUP(20, "udp_shotgun");
+
+    EthernetInterface eth;
+    int err = eth.connect();
+    TEST_ASSERT_EQUAL(0, err);
+
+    printf("MBED: UDPClient IP address is '%s'\n", eth.get_ip_address());
+    printf("MBED: UDPClient waiting for server IP and port...\n");
+
+    greentea_send_kv("target_ip", eth.get_ip_address());
+
+    bool result = false;
+
+    char recv_key[] = "host_port";
+    char ipbuf[60] = {0};
+    char portbuf[16] = {0};
+    unsigned int port = 0;
+
+    greentea_send_kv("host_ip", " ");
+    greentea_parse_kv(recv_key, ipbuf, sizeof(recv_key), sizeof(ipbuf));
+
+    greentea_send_kv("host_port", " ");
+    greentea_parse_kv(recv_key, portbuf, sizeof(recv_key), sizeof(ipbuf));
+    sscanf(portbuf, "%u", &port);
+
+    printf("MBED: UDP Server IP address received: %s:%d \n", ipbuf, port);
+
+    // align each size to 4-bits
+    for (int i = 0; i < udp_dtls_handshake_count; i++) {
+        udp_dtls_handshake_pattern[i] = (~0xf & udp_dtls_handshake_pattern[i]) + 0x10;
+    }
+
+    printf("MBED: [");
+    for (int i = 0; i < udp_dtls_handshake_count; i++) {
+        printf("%d", udp_dtls_handshake_pattern[i]);
+        if (i != udp_dtls_handshake_count-1) {
+            printf(", ");
+        }
+    }
+    printf("]\r\n");
+
+    UDPSocket sock;
+    SocketAddress udp_addr(ipbuf, port);
+
+    for (int attempt = 0; attempt < MBED_CFG_UDP_DTLS_HANDSHAKE_RETRIES; attempt++) {
+        err = sock.open(&eth);
+        TEST_ASSERT_EQUAL(0, err);
+
+        for (int i = 0; i < udp_dtls_handshake_count; i++) {
+            buffer[i] = udp_dtls_handshake_pattern[i] >> 4;
+        }
+
+        err = sock.sendto(udp_addr, buffer, udp_dtls_handshake_count);
+        printf("UDP: tx -> %d\r\n", err);
+        TEST_ASSERT_EQUAL(udp_dtls_handshake_count, err);
+
+        int step = 0;
+        while (step < udp_dtls_handshake_count) {
+            err = sock.recvfrom(NULL, buffer, sizeof(buffer));
+            printf("UDP: rx <- %d ", err);
+
+            // check length
+            if (err != udp_dtls_handshake_pattern[step]) {
+                printf("x (expected %d)\r\n", udp_dtls_handshake_pattern[step]);
+                break;
+            }
+
+            // check quick xor of packet
+            uint8_t check = 0;
+            for (int j = 0; j < udp_dtls_handshake_pattern[step]; j++) {
+                check ^= buffer[j];
+            }
+
+            if (check != 0) {
+                printf("x (checksum 0x%02x)\r\n", check);
+                break;
+            }
+
+            // successfully got a packet
+            printf("\r\n");
+            step += 1;
+        }
+
+        err = sock.close();
+        TEST_ASSERT_EQUAL(0, err);
+
+        // got through all steps, test passed
+        if (step == udp_dtls_handshake_count) {
+            result = true;
+            break;
+        }
+    }
+
+    eth.disconnect();
+    GREENTEA_TESTSUITE_RESULT(result);
+}