Adds SNIPClient, a helper library for sending SNIP requests to remote…

… nodes. (#451)

* Adds SNIPClient, a helper library for sending SNIP requests to remote nodes.

Fixes a bug in the parser method used for OIR errors.

* fix typo.

src/openlcb/If.cxx

@@ -119,11 +119,11 @@ void buffer_to_error(const Payload &payload, uint16_t *error_code,
         error_message->clear();
     if (payload.size() >= 2 && error_code)
     {
-        *error_code = (((uint16_t)payload[0]) << 8) | payload[1];
+        *error_code = (((uint16_t)payload[0]) << 8) | (uint8_t)payload[1];
     }
     if (payload.size() >= 4 && mti)
     {
-        *mti = (((uint16_t)payload[2]) << 8) | payload[3];
+        *mti = (((uint16_t)payload[2]) << 8) | (uint8_t)payload[3];
     }
     if (payload.size() > 4 && error_message)
     {

src/openlcb/SNIPClient.cxxtest

@@ -0,0 +1,160 @@
+/** \copyright
+ * Copyright (c) 2020, Balazs Racz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * \file SNIPClient.cxxtest
+ *
+ * Unit test for SNIP client library.
+ *
+ * @author Balazs Racz
+ * @date 18 Oct 2020
+ */
+
+static long long snipTimeout = 50 * 1000000;
+#define SNIP_CLIENT_TIMEOUT_NSEC snipTimeout
+
+#include "openlcb/SNIPClient.hxx"
+
+#include "openlcb/SimpleNodeInfo.hxx"
+#include "openlcb/SimpleNodeInfoMockUserFile.hxx"
+#include "utils/async_if_test_helper.hxx"
+
+namespace openlcb
+{
+
+const char *const SNIP_DYNAMIC_FILENAME = MockSNIPUserFile::snip_user_file_path;
+
+const SimpleNodeStaticValues SNIP_STATIC_DATA = {
+    4, "TestingTesting", "Undefined model", "Undefined HW version", "0.9"};
+
+class SNIPClientTest : public AsyncNodeTest
+{
+protected:
+    SNIPClientTest()
+    {
+        eb_.release_block();
+        run_x([this]() {
+            ifTwo_.alias_allocator()->TEST_add_allocated_alias(0xFF2);
+        });
+        wait();
+    }
+
+    ~SNIPClientTest()
+    {
+        wait();
+    }
+
+    MockSNIPUserFile userFile_ {"Undefined node name", "Undefined node descr"};
+
+    /// General flow for simple info requests.
+    SimpleInfoFlow infoFlow_ {ifCan_.get()};
+    /// Handles SNIP requests.
+    SNIPHandler snipHandler_ {ifCan_.get(), node_, &infoFlow_};
+    /// The actual client to test.
+    SNIPClient client_ {ifCan_.get()};
+
+    // These objects create a second node on the CAN bus (with its own
+    // interface).
+    BlockExecutor eb_ {&g_executor};
+    static constexpr NodeID TWO_NODE_ID = 0x02010d0000ddULL;
+
+    IfCan ifTwo_ {&g_executor, &can_hub0, local_alias_cache_size,
+        remote_alias_cache_size, local_node_count};
+    AddAliasAllocator alloc_ {TWO_NODE_ID, &ifTwo_};
+    DefaultNode nodeTwo_ {&ifTwo_, TWO_NODE_ID};
+};
+
+TEST_F(SNIPClientTest, create)
+{
+}
+
+static const char kExpectedData[] =
+    "\x04TestingTesting\0Undefined model\0Undefined HW version\0"
+    "0.9\0"
+    "\x02Undefined node name\0Undefined node descr"; // C adds another \0.
+
+TEST_F(SNIPClientTest, localhost)
+{
+    auto b = invoke_flow(&client_, node_, NodeHandle(node_->node_id()));
+    EXPECT_EQ(0, b->data()->resultCode);
+    EXPECT_EQ(
+        string(kExpectedData, sizeof(kExpectedData)), b->data()->response);
+
+    // do another request.
+    auto bb = invoke_flow(&client_, node_, NodeHandle(node_->node_id()));
+    EXPECT_EQ(0, bb->data()->resultCode);
+    EXPECT_EQ(
+        string(kExpectedData, sizeof(kExpectedData)), bb->data()->response);
+}
+
+TEST_F(SNIPClientTest, remote)
+{
+    auto b = invoke_flow(&client_, &nodeTwo_, NodeHandle(node_->node_id()));
+    EXPECT_EQ(0, b->data()->resultCode);
+    EXPECT_EQ(
+        string(kExpectedData, sizeof(kExpectedData)), b->data()->response);
+
+    // do another request.
+    auto bb = invoke_flow(&client_, &nodeTwo_, NodeHandle(node_->node_id()));
+    EXPECT_EQ(0, bb->data()->resultCode);
+    EXPECT_EQ(
+        string(kExpectedData, sizeof(kExpectedData)), bb->data()->response);
+}
+
+TEST_F(SNIPClientTest, timeout)
+{
+    long long start = os_get_time_monotonic();
+    auto b = invoke_flow(&client_, &nodeTwo_, NodeHandle(nodeTwo_.node_id()));
+    EXPECT_EQ(SNIPClientRequest::OPENMRN_TIMEOUT, b->data()->resultCode);
+    EXPECT_EQ(0u, b->data()->response.size());
+    long long time = os_get_time_monotonic() - start;
+    EXPECT_LT(MSEC_TO_NSEC(49), time);
+}
+
+TEST_F(SNIPClientTest, reject)
+{
+    SyncNotifiable n;
+    auto b = get_buffer_deleter(client_.alloc());
+    b->data()->reset(node_, NodeHandle(NodeAlias(0x555)));
+    b->data()->done.reset(&n);
+
+    expect_packet(":X19DE822AN0555;");
+    client_.send(b.get());
+    wait();
+    clear_expect(true);
+    EXPECT_EQ(SNIPClientRequest::OPERATION_PENDING, b->data()->resultCode);
+
+    send_packet(":X19068555N022A209905EB;");
+    wait();
+    EXPECT_EQ(SNIPClientRequest::OPERATION_PENDING, b->data()->resultCode);
+
+    send_packet(":X19068555N022A20990DE8;");
+    wait();
+    EXPECT_EQ(SNIPClientRequest::ERROR_REJECTED | 0x2099, b->data()->resultCode);
+    n.wait_for_notification();
+
+}
+
+} // namespace openlcb

src/openlcb/SNIPClient.hxx

@@ -0,0 +1,198 @@
+/** \copyright
+ * Copyright (c) 2020, Balazs Racz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * \file SNIPClient.hxx
+ *
+ * A client library for talking to an arbitrary openlcb Node and ask it for the
+ * Simple Node Ident Info data.
+ *
+ * @author Balazs Racz
+ * @date 18 Oct 2020
+ */
+
+#ifndef _OPENLCB_SNIPCLIENT_HXX_
+#define _OPENLCB_SNIPCLIENT_HXX_
+
+#include "executor/CallableFlow.hxx"
+#include "openlcb/Defs.hxx"
+#include "openlcb/If.hxx"
+
+namespace openlcb
+{
+
+/// Buffer contents for invoking the SNIP client.
+struct SNIPClientRequest : public CallableFlowRequestBase
+{
+    /// Helper function for invoke_subflow.
+    /// @param src the openlcb node to call from
+    /// @param dst the openlcb node to target
+    void reset(Node *src, NodeHandle dst)
+    {
+        reset_base();
+        resultCode = OPERATION_PENDING;
+        src_ = src;
+        dst_ = dst;
+    }
+
+    enum
+    {
+        OPERATION_PENDING = 0x20000, //< cleared when done is called.
+        ERROR_REJECTED = 0x200000,   //< Target node has rejected the request.
+        OPENMRN_TIMEOUT = 0x80000,   //< Timeout waiting for ack/nack.
+    };
+
+    /// Source node where to send the request from.
+    Node *src_;
+    /// Destination node to query.
+    NodeHandle dst_;
+    /// Response payload if successful.
+    Payload response;
+};
+
+#if !defined(GTEST) || !defined(SNIP_CLIENT_TIMEOUT_NSEC)
+/// Specifies how long to wait for a SNIP request to get a response. Writable
+/// for unittesting purposes.
+static constexpr long long SNIP_CLIENT_TIMEOUT_NSEC = MSEC_TO_NSEC(1500);
+#endif
+
+class SNIPClient : public CallableFlow<SNIPClientRequest>
+{
+public:
+    /// Constructor.
+    /// @param s service of the openlcb executor.
+    SNIPClient(Service *s)
+        : CallableFlow<SNIPClientRequest>(s)
+    {
+    }
+
+    Action entry() override
+    {
+        request()->resultCode = SNIPClientRequest::OPERATION_PENDING;
+        return allocate_and_call(
+            iface()->addressed_message_write_flow(), STATE(write_request));
+    }
+
+private:
+    enum
+    {
+        MTI_1a = Defs::MTI_TERMINATE_DUE_TO_ERROR,
+        MTI_1b = Defs::MTI_OPTIONAL_INTERACTION_REJECTED,
+        MASK_1 = ~(MTI_1a ^ MTI_1b),
+        MTI_1 = MTI_1a,
+
+        MTI_2 = Defs::MTI_IDENT_INFO_REPLY,
+        MASK_2 = Defs::MTI_EXACT,
+    };
+
+    /// Called once the allocation is complete. Sends out the SNIP request to
+    /// the bus.
+    Action write_request()
+    {
+        auto *b =
+            get_allocation_result(iface()->addressed_message_write_flow());
+        b->data()->reset(Defs::MTI_IDENT_INFO_REQUEST,
+            request()->src_->node_id(), request()->dst_, EMPTY_PAYLOAD);
+
+        iface()->dispatcher()->register_handler(
+            &responseHandler_, MTI_1, MASK_1);
+        iface()->dispatcher()->register_handler(
+            &responseHandler_, MTI_2, MASK_2);
+
+        iface()->addressed_message_write_flow()->send(b);
+
+        return sleep_and_call(
+            &timer_, SNIP_CLIENT_TIMEOUT_NSEC, STATE(response_came));
+    }
+
+    /// Callback from the response handler.
+    /// @param message the incoming response message from the bus
+    void handle_response(Buffer<GenMessage> *message)
+    {
+        auto rb = get_buffer_deleter(message);
+        if (request()->src_ != message->data()->dstNode ||
+            !iface()->matching_node(request()->dst_, message->data()->src))
+        {
+            // Not from the right place.
+            return;
+        }
+        if (message->data()->mti == Defs::MTI_OPTIONAL_INTERACTION_REJECTED ||
+            message->data()->mti == Defs::MTI_TERMINATE_DUE_TO_ERROR)
+        {
+            uint16_t mti, error_code;
+            buffer_to_error(
+                message->data()->payload, &error_code, &mti, nullptr);
+            LOG(INFO, "rejection err %04x mti %04x", error_code, mti);
+            if (mti && mti != Defs::MTI_IDENT_INFO_REQUEST)
+            {
+                // Got error response for a different interaction. Ignore.
+                return;
+            }
+            request()->resultCode =
+                error_code | SNIPClientRequest::ERROR_REJECTED;
+        }
+        else if (message->data()->mti == Defs::MTI_IDENT_INFO_REPLY)
+        {
+            request()->response = std::move(message->data()->payload);
+            request()->resultCode = 0;
+        }
+        else
+        {
+            // Dunno what this MTI is. Ignore.
+            LOG(INFO, "Unexpected MTI for SNIP response handler: %04x",
+                message->data()->mti);
+            return;
+        }
+        // Wakes up parent flow.
+        request()->resultCode &= ~SNIPClientRequest::OPERATION_PENDING;
+        timer_.trigger();
+    }
+
+    Action response_came()
+    {
+        iface()->dispatcher()->unregister_handler_all(&responseHandler_);
+        if (request()->resultCode & SNIPClientRequest::OPERATION_PENDING)
+        {
+            return return_with_error(SNIPClientRequest::OPENMRN_TIMEOUT);
+        }
+        return return_with_error(request()->resultCode);
+    }
+
+    /// @return openlcb source interface.
+    If *iface()
+    {
+        return request()->src_->iface();
+    }
+
+    /// Handles the timeout feature.
+    StateFlowTimer timer_ {this};
+    /// Registered handler for response messages.
+    IncomingMessageStateFlow::GenericHandler responseHandler_ {
+        this, &SNIPClient::handle_response};
+};
+
+} // namespace openlcb
+
+#endif // _OPENLCB_SNIPCLIENT_HXX_