dnp3 · emgre · Apr 12, 2022 · Nov 17, 2020 · Nov 17, 2020 · Nov 17, 2020
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -89,7 +89,7 @@ jobs:
       matrix:
         build-type: [Debug, Release]
         architecture: [x86, x64]
-    runs-on: windows-latest
+    runs-on: windows-2019
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -98,7 +98,7 @@ jobs:
           if("${{ matrix.architecture }}" -eq "x86") { $flag = "--x86" } else { $flag = "" };
           choco install --no-progress "$flag" cmake.portable nuget.commandline openssl; mkdir build
       - name: Install Java
-        uses: actions/setup-java@v1.4.3
+        uses: actions/setup-java@v1
         with:
           java-version: 8
           java-package: jdk

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ### Next ###
 * :beetle: Fix `PrintingSOEHandler` octet string size not printing properly.
+  See [4372862](https://github.com/dnp3/opendnp3/commit/4372862728851f559a01edcd88bc15ce6ce7f350)
+* :beetle: Fix keep-alive timer not properly calculated. See [#407](https://github.com/dnp3/opendnp3/pull/407).
+* :beetle: Fix `LinkContext` and `MContext` possible lifetime issue.
+  See [#407](https://github.com/dnp3/opendnp3/pull/407).
 
 ### 3.1.1 ###
 * :beetle: Fix static octet string serilazation bug.

diff --git a/cpp/lib/src/link/LinkContext.cpp b/cpp/lib/src/link/LinkContext.cpp
@@ -50,6 +50,16 @@ LinkContext::LinkContext(const Logger& logger,
 {
 }
 
+std::shared_ptr<LinkContext> LinkContext::Create(const Logger& logger,
+                                                 const std::shared_ptr<exe4cpp::IExecutor>& executor,
+                                                 std::shared_ptr<IUpperLayer> upper,
+                                                 std::shared_ptr<ILinkListener> listener,
+                                                 ILinkSession& session,
+                                                 const LinkLayerConfig& config)
+{
+    return std::shared_ptr<LinkContext>(new LinkContext(logger, executor, upper, listener, session, config));
+}
+
 bool LinkContext::OnLowerLayerUp()
 {
     if (this->isOnline)
@@ -58,13 +68,9 @@ bool LinkContext::OnLowerLayerUp()
         return false;
     }
 
-    const auto now = Timestamp(this->executor->get_time());
-
     this->isOnline = true;
 
-    this->lastMessageTimestamp = now; // no reason to trigger a keep-alive until we've actually expired
-
-    this->StartKeepAliveTimer(now + config.KeepAliveTimeout);
+    this->RestartKeepAliveTimer();
 
     listener->OnStateChange(LinkStatus::UNRESET);
     upper->OnLowerLayerUp();
@@ -230,16 +236,14 @@ void LinkContext::TryStartTransmission()
 void LinkContext::OnKeepAliveTimeout()
 {
     const auto now = Timestamp(this->executor->get_time());
-
-    auto elapsed = now - this->lastMessageTimestamp;
+    const auto elapsed = now - this->lastMessageTimestamp;
 
     if (elapsed >= this->config.KeepAliveTimeout)
     {
-        this->lastMessageTimestamp = now;
         this->keepAliveTimeout = true;
     }
 
-    this->StartKeepAliveTimer(now + config.KeepAliveTimeout);
+    this->RestartKeepAliveTimer();
 
     this->TryStartTransmission();
 }
@@ -253,12 +257,27 @@ void LinkContext::OnResponseTimeout()
 
 void LinkContext::StartResponseTimer()
 {
-    rspTimeoutTimer = executor->start(config.Timeout.value, [this]() { this->OnResponseTimeout(); });
+    this->rspTimeoutTimer = executor->start(config.Timeout.value, [self = shared_from_this()]() {
+        if (self->isOnline)
+        {
+            self->OnResponseTimeout();
+        }
+    });
 }
 
-void LinkContext::StartKeepAliveTimer(const Timestamp& expiration)
+void LinkContext::RestartKeepAliveTimer()
 {
-    this->keepAliveTimer = executor->start(expiration.value, [this]() { this->OnKeepAliveTimeout(); });
+    this->keepAliveTimer.cancel();
+
+    this->lastMessageTimestamp = Timestamp(this->executor->get_time());
+    const auto expiration = this->lastMessageTimestamp + this->config.KeepAliveTimeout;
+
+    this->keepAliveTimer = executor->start(expiration.value, [self = shared_from_this()]() {
+        if (self->isOnline)
+        {
+            self->OnKeepAliveTimeout();
+        }
+    });
 }
 
 void LinkContext::CancelTimer()
@@ -310,31 +329,19 @@ bool LinkContext::OnFrame(const LinkHeaderFields& header, const ser4cpp::rseq_t&
         return false;
     }
 
-    if (header.addresses.IsBroadcast())
+    // Broadcast addresses can only be used for sending data.
+    // If confirmed data is used, no response is sent back.
+    if (header.addresses.IsBroadcast() &&
+        !(header.func == LinkFunction::PRI_UNCONFIRMED_USER_DATA || header.func == LinkFunction::PRI_CONFIRMED_USER_DATA))
     {
-        // Broadcast addresses can only be used for sending data.
-        // If confirmed data is used, no response is sent back.
-        if (header.func == LinkFunction::PRI_UNCONFIRMED_USER_DATA)
-        {
-            this->PushDataUp(Message(header.addresses, userdata));
-            return true;
-        }
-        else if (header.func == LinkFunction::PRI_CONFIRMED_USER_DATA)
-        {
-            pSecState = &pSecState->OnConfirmedUserData(*this, header.addresses.source, header.fcb, true,
-                                                        Message(header.addresses, userdata));
-        }
-        else
-        {
-            FORMAT_LOG_BLOCK(logger, flags::WARN, "Received invalid function (%s) with broadcast destination address",
-                             LinkFunctionSpec::to_string(header.func));
-            ++statistics.numUnexpectedFrame;
-            return false;
-        }
+        FORMAT_LOG_BLOCK(logger, flags::WARN, "Received invalid function (%s) with broadcast destination address",
+                            LinkFunctionSpec::to_string(header.func));
+        ++statistics.numUnexpectedFrame;
+        return false;
     }
 
     // reset the keep-alive timestamp
-    this->lastMessageTimestamp = Timestamp(this->executor->get_time());
+    this->RestartKeepAliveTimer();
 
     switch (header.func)
     {
@@ -360,7 +367,7 @@ bool LinkContext::OnFrame(const LinkHeaderFields& header, const ser4cpp::rseq_t&
         pSecState = &pSecState->OnRequestLinkStatus(*this, header.addresses.source);
         break;
     case (LinkFunction::PRI_CONFIRMED_USER_DATA):
-        pSecState = &pSecState->OnConfirmedUserData(*this, header.addresses.source, header.fcb, false,
+        pSecState = &pSecState->OnConfirmedUserData(*this, header.addresses.source, header.fcb, header.addresses.IsBroadcast(),
                                                     Message(header.addresses, userdata));
         break;
     case (LinkFunction::PRI_UNCONFIRMED_USER_DATA):

diff --git a/cpp/lib/src/link/LinkContext.h b/cpp/lib/src/link/LinkContext.h
@@ -37,6 +37,8 @@
 
 #include <exe4cpp/IExecutor.h>
 
+#include <memory>
+
 namespace opendnp3
 {
 
@@ -51,17 +53,23 @@ enum class LinkTransmitMode : uint8_t
 };
 
 //	@section desc Implements the contextual state of DNP3 Data Link Layer
-class LinkContext
+class LinkContext : public std::enable_shared_from_this<LinkContext>
 {
-
-public:
     LinkContext(const Logger& logger,
                 const std::shared_ptr<exe4cpp::IExecutor>&,
                 std::shared_ptr<IUpperLayer>,
                 std::shared_ptr<ILinkListener>,
                 ILinkSession& session,
                 const LinkLayerConfig&);
 
+public:
+    static std::shared_ptr<LinkContext> Create(const Logger& logger,
+                                               const std::shared_ptr<exe4cpp::IExecutor>&,
+                                               std::shared_ptr<IUpperLayer>,
+                                               std::shared_ptr<ILinkListener>,
+                                               ILinkSession& session,
+                                               const LinkLayerConfig&);
+
     // ---- helpers for dealing with the FCB bits ----
 
     void ResetReadFCB()
@@ -97,7 +105,7 @@ class LinkContext
     void OnKeepAliveTimeout();
     void OnResponseTimeout();
     void StartResponseTimer();
-    void StartKeepAliveTimer(const Timestamp& expiration);
+    void RestartKeepAliveTimer();
     void CancelTimer();
     void FailKeepAlive(bool timeout);
     void CompleteKeepAlive();

diff --git a/cpp/lib/src/link/LinkLayer.cpp b/cpp/lib/src/link/LinkLayer.cpp
@@ -27,19 +27,19 @@ LinkLayer::LinkLayer(const Logger& logger,
                      const std::shared_ptr<IUpperLayer>& upper,
                      const std::shared_ptr<ILinkListener>& listener,
                      const LinkLayerConfig& config)
-    : ctx(logger, executor, upper, listener, *this, config)
+    : ctx(LinkContext::Create(logger, executor, upper, listener, *this, config))
 {
 }
 
 const StackStatistics::Link& LinkLayer::GetStatistics() const
 {
-    return this->ctx.statistics;
+    return this->ctx->statistics;
 }
 
 void LinkLayer::SetRouter(ILinkTx& router)
 {
-    assert(!ctx.linktx);
-    ctx.linktx = &router;
+    assert(!ctx->linktx);
+    ctx->linktx = &router;
 }
 
 ////////////////////////////////
@@ -48,12 +48,12 @@ void LinkLayer::SetRouter(ILinkTx& router)
 
 bool LinkLayer::Send(ITransportSegment& segments)
 {
-    if (!ctx.isOnline)
+    if (!ctx->isOnline)
         return false;
 
-    if (ctx.SetTxSegment(segments))
+    if (ctx->SetTxSegment(segments))
     {
-        ctx.TryStartTransmission();
+        ctx->TryStartTransmission();
     }
 
     return true;
@@ -65,21 +65,21 @@ bool LinkLayer::Send(ITransportSegment& segments)
 
 bool LinkLayer::OnLowerLayerUp()
 {
-    return ctx.OnLowerLayerUp();
+    return ctx->OnLowerLayerUp();
 }
 
 bool LinkLayer::OnLowerLayerDown()
 {
-    return ctx.OnLowerLayerDown();
+    return ctx->OnLowerLayerDown();
 }
 
 bool LinkLayer::OnTxReady()
 {
-    auto ret = ctx.OnTxReady();
+    auto ret = ctx->OnTxReady();
 
     if (ret)
     {
-        ctx.TryStartTransmission();
+        ctx->TryStartTransmission();
     }
 
     return true;
@@ -91,11 +91,11 @@ bool LinkLayer::OnTxReady()
 
 bool LinkLayer::OnFrame(const LinkHeaderFields& header, const ser4cpp::rseq_t& userdata)
 {
-    auto ret = this->ctx.OnFrame(header, userdata);
+    auto ret = this->ctx->OnFrame(header, userdata);
 
     if (ret)
     {
-        this->ctx.TryStartTransmission();
+        this->ctx->TryStartTransmission();
     }
 
     return ret;

diff --git a/cpp/lib/src/link/LinkLayer.h b/cpp/lib/src/link/LinkLayer.h
@@ -23,6 +23,8 @@
 #include "LinkContext.h"
 #include "LinkLayerConfig.h"
 
+#include <memory>
+
 namespace opendnp3
 {
 
@@ -54,7 +56,7 @@ class LinkLayer final : public ILinkLayer, public ILinkSession
 
 private:
     // The full state
-    LinkContext ctx;
+    std::shared_ptr<LinkContext> ctx;
 };
 
 } // namespace opendnp3

diff --git a/cpp/lib/src/master/MasterContext.cpp b/cpp/lib/src/master/MasterContext.cpp
@@ -59,6 +59,19 @@ MContext::MContext(const Addresses& addresses,
 {
 }
 
+std::shared_ptr<MContext> MContext::Create(
+    const Addresses& addresses,
+    const Logger& logger,
+    const std::shared_ptr<exe4cpp::IExecutor>& executor,
+    std::shared_ptr<ILowerLayer> lower,
+    const std::shared_ptr<ISOEHandler>& SOEHandler,
+    const std::shared_ptr<IMasterApplication>& application,
+    std::shared_ptr<IMasterScheduler> scheduler,
+    const MasterParams& params)
+{
+    return std::shared_ptr<MContext>(new MContext(addresses, logger, executor, lower, SOEHandler, application, scheduler, params));
+}
+
 bool MContext::OnLowerLayerUp()
 {
     if (isOnline)
@@ -289,7 +302,7 @@ void MContext::Transmit(const ser4cpp::rseq_t& data)
 
 void MContext::StartResponseTimer()
 {
-    auto timeout = [this]() { this->OnResponseTimeout(); };
+    auto timeout = [self = shared_from_this()]() { self->OnResponseTimeout(); };
     this->responseTimer = this->executor->start(this->params.responseTimeout.value, timeout);
 }
 

diff --git a/cpp/lib/src/master/MasterContext.h b/cpp/lib/src/master/MasterContext.h
@@ -40,14 +40,24 @@
 #include <exe4cpp/asio/StrandExecutor.h>
 
 #include <deque>
+#include <memory>
 
 namespace opendnp3
 {
 /*
     All of the mutable state and configuration for a master
 */
-class MContext final : public IUpperLayer, private IMasterTaskRunner, private Uncopyable
+class MContext final : public IUpperLayer, public std::enable_shared_from_this<MContext>, private IMasterTaskRunner, private Uncopyable
 {
+private:
+    MContext(const Addresses& addresses,
+             const Logger& logger,
+             const std::shared_ptr<exe4cpp::IExecutor>& executor,
+             std::shared_ptr<ILowerLayer> lower,
+             const std::shared_ptr<ISOEHandler>& SOEHandler,
+             const std::shared_ptr<IMasterApplication>& application,
+             std::shared_ptr<IMasterScheduler> scheduler,
+             const MasterParams& params);
 
 public:
     enum class TaskState
@@ -57,14 +67,16 @@ class MContext final : public IUpperLayer, private IMasterTaskRunner, private Un
         WAIT_FOR_RESPONSE
     };
 
-    MContext(const Addresses& addresses,
-             const Logger& logger,
-             const std::shared_ptr<exe4cpp::IExecutor>& executor,
-             std::shared_ptr<ILowerLayer> lower,
-             const std::shared_ptr<ISOEHandler>& SOEHandler,
-             const std::shared_ptr<IMasterApplication>& application,
-             std::shared_ptr<IMasterScheduler> scheduler,
-             const MasterParams& params);
+    static std::shared_ptr<MContext> Create(
+        const Addresses& addresses,
+        const Logger& logger,
+        const std::shared_ptr<exe4cpp::IExecutor>& executor,
+        std::shared_ptr<ILowerLayer> lower,
+        const std::shared_ptr<ISOEHandler>& SOEHandler,
+        const std::shared_ptr<IMasterApplication>& application,
+        std::shared_ptr<IMasterScheduler> scheduler,
+        const MasterParams& params
+    );
 
     Logger logger;
     const std::shared_ptr<exe4cpp::IExecutor> executor;