Control SD sync/async behaviour with env var on QNX

This is a change intended for systems like QNX which do not generally
have a service like netlink monitoring the network status that can
easily be tied into.  This is not setup to be used/enabled on Linux/Android.

SD will use the new asynchronous behaviour if the env var
VSOMEIP_USE_ASYNCHRONOUS_SD is set.  If not set, SD will use a
synchronous behaviour and only wait for the interface if the env var
VSOMEIP_WAIT_FOR_INTERFACE exists.  The latter (without waiting) is very
close to the upstream behaviour, the difference being that a callback is
still sent to sd::start() from routing_manager_impl, rather than
executing that code directly in routing_manager_impl.

Notes:
- mutexes
  - sd_impl::endpoint_ is now mutex protected
  - rm_impl::pending_sd_offers_mutex_ is a recursive mutex, as now it
    can be called in its own thread and the new thread in SD
- There is no timeout on the waitfor.  The original implementation had a
  configurable timeout, however because timing out left us in an error
  state anyways, this timeout was removed (raised to
  numeric_limits<int>::max() = ~45 days, give or take.)

documentation/vsomeipUserGuide

@@ -284,7 +284,7 @@ On startup the following environment variables are read out:
    Please note that <application> must be valid as part of an environment variable.
 * `VSOMEIP_MANDATORY_CONFIGURATION_FILES`: vsomeip allows to specify mandatory configuration
    files to speed-up application startup. While mandatory configuration files are read by all
-   applications, all other configuration files are only read by the application that is 
+   applications, all other configuration files are only read by the application that is
    responsible for connections to external devices. If this configuration variable is not set,
    the default mandatory files vsomeip_std.json, vsomeip_app.json and vsomeip_plc.json are used.
 * `VSOMEIP_CLIENTSIDELOGGING`: Set this variable to an empty string to enable logging of
@@ -296,6 +296,16 @@ On startup the following environment variables are read out:
    `Environment=VSOMEIP_CLIENTSIDELOGGING="b003.0001 f013.000a 1001 1002"`
    `Environment=VSOMEIP_CLIENTSIDELOGGING="b003.0001:f013.000a:1001:1002"`
 
+For systems without a netlink service (_e.g._ QNX):
+* `VSOMEIP_USE_ASYNCHRONOUS_SD`: (QNX only) Enables service discovery to run asynchronously
+   on startup and to (if enabled) wait on network availability.
+* `VSOMEIP_WAIT_FOR_INTERFACE`: Iff service discovery is running
+   asynchronously, this env var will cause it to block on network availability
+   (mostly for use in a testing scenario.)
+* `VSOMEIP_NETWORK_INT_READY_FILE`: Full path of the file that service
+   discovery is waiting on (waiting for the creation of) to indicate that a
+   network is available.
+
 NOTE: If the file/folder that is configured by `VSOMEIP_CONFIGURATION` does _not_ exist,
 the default configuration locations will be used.
 

implementation/configuration/include/internal.hpp.in

@@ -33,6 +33,25 @@
 
 #define VSOMEIP_ROUTING_HOST_PORT_DEFAULT       31490
 
+//
+// Defines related to running SD asynchronously - this is not available upstream
+
+// Env var that if exists will cause SD setup to be performed asynchronously and
+// wait on network availability.  This wait also impacts the routing_manager to
+// also wait until a network interface is available before issuring OFFERs
+#define VSOMEIP_ENV_USE_ASYNCHRONOUS_SD         "VSOMEIP_USE_ASYNCHRONOUS_SD"
+
+// Iff SD is running synchronously, the existence of this env var will cause the
+// SD setup to still block on network availability. (mostly a testing scenario)
+#define VSOMEIP_ENV_WAIT_FOR_INTERFACE          "VSOMEIP_WAIT_FOR_INTERFACE"
+
+// The current waiting mechanism is to block until a file (specified by this
+// define)
+#define VSOMEIP_NETWORK_INT_READY_FILE          "@VSOMEIP_NETWORK_INT_READY_FILE@"
+
+// /end of async change
+//
+
 #ifdef _WIN32
 #define VSOMEIP_CFG_LIBRARY                      "vsomeip3-cfg.dll"
 #else

implementation/routing/include/routing_manager_impl.hpp

@@ -495,7 +495,7 @@ class routing_manager_impl: public routing_manager_base,
     bool if_state_running_;
     bool sd_route_set_;
     bool routing_running_;
-    std::mutex pending_sd_offers_mutex_;
+    std::recursive_mutex pending_sd_offers_mutex_;
     std::vector<std::pair<service_t, instance_t>> pending_sd_offers_;
 #if defined(__linux__) || defined(ANDROID)
     std::shared_ptr<netlink_connector> netlink_connector_;

implementation/routing/src/routing_manager_impl.cpp

@@ -236,7 +236,7 @@ void routing_manager_impl::start() {
     netlink_connector_->start();
 #else
     {
-        std::lock_guard<std::mutex> its_lock(pending_sd_offers_mutex_);
+        std::lock_guard its_lock(pending_sd_offers_mutex_);
         start_ip_routing();
     }
 #endif
@@ -448,7 +448,7 @@ bool routing_manager_impl::offer_service(client_t _client,
     }
 
     {
-        std::lock_guard<std::mutex> its_lock(pending_sd_offers_mutex_);
+        std::lock_guard its_lock(pending_sd_offers_mutex_);
         if (if_state_running_) {
             init_service_info(_service, _instance, true);
         } else {
@@ -542,7 +542,7 @@ void routing_manager_impl::stop_offer_service(client_t _client,
     }
     if (is_local) {
         {
-            std::lock_guard<std::mutex> its_lock(pending_sd_offers_mutex_);
+            std::lock_guard its_lock(pending_sd_offers_mutex_);
             for (auto it = pending_sd_offers_.begin(); it != pending_sd_offers_.end(); ) {
                 if (it->first == _service && it->second == _instance) {
                     it = pending_sd_offers_.erase(it);
@@ -3881,7 +3881,7 @@ void routing_manager_impl::set_routing_state(routing_state_e _routing_state) {
                 }
 
                 // start processing of SD messages (incoming remote offers should lead to new subscribe messages)
-                discovery_->start();
+                discovery_->start([]() { });
 
                 // Trigger initial offer phase for relevant services
                 for (const auto &its_service : get_offered_services()) {
@@ -3950,7 +3950,7 @@ void routing_manager_impl::set_routing_state(routing_state_e _routing_state) {
 
 void routing_manager_impl::on_net_interface_or_route_state_changed(
         bool _is_interface, const std::string &_if, bool _available) {
-    std::lock_guard<std::mutex> its_lock(pending_sd_offers_mutex_);
+    std::lock_guard its_lock(pending_sd_offers_mutex_);
     auto log_change_message = [&_if, _available, _is_interface](bool _warning) {
         std::stringstream ss;
         ss << (_is_interface ? "Network interface" : "Route") << " \"" << _if
@@ -4000,26 +4000,30 @@ void routing_manager_impl::on_net_interface_or_route_state_changed(
 }
 
 void routing_manager_impl::start_ip_routing() {
-#if defined(_WIN32) || defined(__QNX__)
+#if defined(_WIN32)
     if_state_running_ = true;
 #endif
 
-    if (routing_ready_handler_) {
-        routing_ready_handler_();
-    }
+    auto on_routing_started = [this]() -> void
+    {
+        std::lock_guard its_lock(pending_sd_offers_mutex_);
+
+        if_state_running_ = true;
+        for (auto const& its_service : pending_sd_offers_) {
+            init_service_info(its_service.first, its_service.second, true);
+        }
+        pending_sd_offers_.clear();
+
+        routing_running_ = true;
+        VSOMEIP_INFO << VSOMEIP_ROUTING_READY_MESSAGE;
+    };
+
     if (discovery_) {
-        discovery_->start();
+        discovery_->start(on_routing_started);
     } else {
         init_routing_info();
+        on_routing_started();
     }
-
-    for (auto its_service : pending_sd_offers_) {
-        init_service_info(its_service.first, its_service.second, true);
-    }
-    pending_sd_offers_.clear();
-
-    routing_running_ = true;
-    VSOMEIP_INFO << VSOMEIP_ROUTING_READY_MESSAGE;
 }
 
 void

implementation/service_discovery/include/service_discovery.hpp

@@ -30,7 +30,7 @@ class service_discovery {
     virtual boost::asio::io_context &get_io() = 0;
 
     virtual void init() = 0;
-    virtual void start() = 0;
+    virtual void start(std::function<void(void)> on_routing_started) = 0;
     virtual void stop() = 0;
 
     virtual void request_service(service_t _service, instance_t _instance,

implementation/service_discovery/include/service_discovery_impl.hpp

@@ -12,6 +12,7 @@
 #include <set>
 #include <forward_list>
 #include <atomic>
+#include <thread>
 #include <tuple>
 
 #include <boost/asio/steady_timer.hpp>
@@ -67,7 +68,12 @@ class service_discovery_impl: public service_discovery,
     std::recursive_mutex& get_subscribed_mutex();
 
     void init();
-    void start();
+    void start(std::function<void(void)> on_routing_started);
+
+    // Function that'll do the startup work of SD, either in a new thread or
+    // in the current thread depending on the user's choice
+    void do_start_sd(std::function<void(void)> on_complete, bool wait_for_if);
+
     void stop();
 
     void request_service(service_t _service, instance_t _instance,
@@ -367,7 +373,9 @@ class service_discovery_impl: public service_discovery,
     boost::asio::ip::address unicast_;
     uint16_t port_;
     bool reliable_;
+    std::mutex endpoint_mutex_;
     std::shared_ptr<endpoint> endpoint_;
+    std::thread endpoint_getter_thread_;
 
     std::shared_ptr<serializer> serializer_;
     std::shared_ptr<deserializer> deserializer_;

implementation/service_discovery/src/service_discovery_impl.cpp

@@ -5,12 +5,23 @@
 
 #include <vsomeip/constants.hpp>
 
+#if defined(__linux__) || defined(ANDROID) || defined(__QNX__)
+#include <pthread.h>
+#endif
+
 #include <chrono>
 #include <iomanip>
 #include <forward_list>
 #include <random>
 #include <thread>
 
+#include <chrono>
+
+#ifdef __QNX__
+#include <string_view>
+#include <libgen.h>
+#endif
+
 #include <vsomeip/internal/logger.hpp>
 
 #include "../include/constants.hpp"
@@ -71,7 +82,7 @@ service_discovery_impl::service_discovery_impl(
       find_debounce_time_(VSOMEIP_SD_DEFAULT_FIND_DEBOUNCE_TIME),
       find_debounce_timer_(_host->get_io()),
       main_phase_timer_(_host->get_io()),
-      is_suspended_(false),
+      is_suspended_(true), // Start suspended: this is different than upstream as we start before a network interface is available
       is_diagnosis_(false),
       last_msg_received_timer_(_host->get_io()),
       last_msg_received_timer_timeout_(VSOMEIP_SD_DEFAULT_CYCLIC_OFFER_DELAY +
@@ -80,8 +91,7 @@ service_discovery_impl::service_discovery_impl(
     next_subscription_expiration_ = std::chrono::steady_clock::now() + std::chrono::hours(24);
 }
 
-service_discovery_impl::~service_discovery_impl() {
-}
+service_discovery_impl::~service_discovery_impl() = default;
 
 boost::asio::io_context &service_discovery_impl::get_io() {
     return io_;
@@ -158,16 +168,64 @@ service_discovery_impl::init() {
             + (cyclic_offer_delay_ / 10);
 }
 
-void
-service_discovery_impl::start() {
+auto wait_for_interface() -> bool {
+#ifdef __QNX__
+    static std::string_view constexpr path = VSOMEIP_NETWORK_INT_READY_FILE;
+    if (path.empty()) {
+        VSOMEIP_ERROR << "No network interface signal path defined, service discovery will effectively be disabled.";
+        return false;
+    }
+    // Indefinite delay.  If the condition we're waiting for doesn't occur then
+    // we are in an error state and thus should not continue.
+    static auto constexpr delay_ms = std::numeric_limits<int>::max();
+    static int constexpr poll_ms = 50;
+
+    auto const start = std::chrono::steady_clock::now();
+    VSOMEIP_DEBUG << "Waiting (blocking) indefinitely on network interface (signal=" << path << ")";
+    auto const r = waitfor(path.data(), delay_ms, poll_ms);
+    auto const end = std::chrono::steady_clock::now();
+    auto diff = end - start;
+    if (0 == r)
+    {
+        VSOMEIP_DEBUG << "Waited (blocked) for network interface (signal=" << path << ") for " << std::chrono::duration_cast<std::chrono::milliseconds>(diff).count() << " ms.";
+        return true;
+    } else {
+        VSOMEIP_ERROR << "Timedout waiting for network interface (signal=" << path << ") after " << std::chrono::duration_cast<std::chrono::milliseconds>(diff).count() << " ms: errno=" << errno << ", msg=" << strerror(errno);
+        return false;
+    }
+#else
+    // Omitting a Linux implementation.
+    //
+    // Currently the Linux implementations use netlink in routing_manager_impl to
+    // receive network events, so this function wouldnt be expected to be used. In
+    // theory the QNX implementation could be modified to use pps (if available)
+    // to mirror the Linux functionality, which would avoid this function entirely.
+    //
+    // If however an implementation on linux wanted to use a pattern similar to
+    // this, inotify would likely be the best candidate to monitor the filesystem
+    // for this file.
+  return true;
+#endif
+}
+
+void service_discovery_impl::do_start_sd(std::function<void(void)> on_complete, bool wait_for_if)
+{
+    bool wait_for_result = false;
+    if (wait_for_if)
+    {
+        wait_for_result = wait_for_interface();
+    }
+
+    std::lock_guard<std::mutex> its_lock(endpoint_mutex_);
     if (!endpoint_) {
         endpoint_ = host_->create_service_discovery_endpoint(
                 sd_multicast_, port_, reliable_);
         if (!endpoint_) {
-            VSOMEIP_ERROR << "Couldn't start service discovery";
+            VSOMEIP_ERROR << "Couldn't start service discovery" << (wait_for_result ? "" : " - likely due to timeing out waiting for a network interface");
             return;
         }
     }
+
     {
         std::lock_guard<std::mutex> its_lock(sessions_received_mutex_);
         sessions_received_.clear();
@@ -185,20 +243,61 @@ service_discovery_impl::start() {
                 i.second->set_sent_counter(0);
             }
         }
-
-        // rejoin multicast group
         if (endpoint_ && !reliable_) {
-            auto its_server_endpoint
-                = std::dynamic_pointer_cast<udp_server_endpoint_impl>(endpoint_);
-            if (its_server_endpoint)
-                its_server_endpoint->join(sd_multicast_);
+            // rejoin multicast group
+            dynamic_cast<udp_server_endpoint_impl*>(
+                    endpoint_.get())->join(sd_multicast_);
         }
     }
     is_suspended_ = false;
     start_main_phase_timer();
     start_offer_debounce_timer(true);
     start_find_debounce_timer(true);
     start_ttl_timer();
+
+    on_complete();
+}
+
+void
+service_discovery_impl::start(std::function<void(void)> on_routing_started) {
+#if defined(__QNX__)
+    auto* const use_async_sd = getenv(VSOMEIP_ENV_USE_ASYNCHRONOUS_SD);
+#else
+    // Linux/Android uses netlink, so there's less need for this
+    // asynchroneous service discovery
+    const char* use_async_sd = nullptr;
+#endif
+
+    if (use_async_sd)
+    {
+        // Perform the SD setup in a new thread, and use a wait in that block
+        // to wait for the network to be available
+        VSOMEIP_DEBUG << "Starting service discovery using separate thread";
+        endpoint_getter_thread_ = std::thread(&service_discovery_impl::do_start_sd, this, on_routing_started, true);
+        endpoint_getter_thread_.detach();
+#if defined(__linux__) || defined(ANDROID) || defined(__QNX__)
+        {
+            auto err = pthread_setname_np(endpoint_getter_thread_.native_handle(), "sd_start");
+            if (err) {
+                VSOMEIP_ERROR << "Could not rename SD thread: " << errno << ":" << strerror(errno);
+            }
+        }
+#endif
+    } else {
+        // Perform the SD setup in the current thread (synchronously), and
+        // if VSOMEIP_ENV_WAIT_FOR_INTERFACE exists use a wait in that block
+        // to wait for the network to be available.  Note that
+        // VSOMEIP_ENV_WAIT_FOR_INTERFACE mostly exists for performance
+        // testing.
+
+#if defined(__QNX__)
+        auto* const wait_for_interface_env = getenv(VSOMEIP_ENV_WAIT_FOR_INTERFACE);
+#else
+        const char* wait_for_interface_env = nullptr;
+#endif
+        VSOMEIP_DEBUG << "Starting service discovery using main thread" << (wait_for_interface_env ? ", will block for network interface" : ", will assume network interface pre-exists");
+        do_start_sd(on_routing_started, wait_for_interface_env != nullptr);
+    }
 }
 
 void
@@ -3508,6 +3607,7 @@ service_discovery_impl::on_last_msg_received_timer_expired(
                 std::dec << last_msg_received_timer_timeout_.count() << "ms.";
 
         // Rejoin multicast group
+        std::lock_guard<std::mutex> its_lock(endpoint_mutex_);
         if (endpoint_ && !reliable_) {
             auto its_server_endpoint
                 = std::dynamic_pointer_cast<udp_server_endpoint_impl>(endpoint_);
@@ -3518,7 +3618,7 @@ service_discovery_impl::on_last_msg_received_timer_expired(
         }
         {
             boost::system::error_code ec;
-            std::lock_guard<std::mutex> its_lock(last_msg_received_timer_mutex_);
+            std::lock_guard<std::mutex> its_lock_inner(last_msg_received_timer_mutex_);
             last_msg_received_timer_.expires_from_now(last_msg_received_timer_timeout_, ec);
             last_msg_received_timer_.async_wait(
                     std::bind(