commit da366d88ae6905b5e0f79e62168e58fb2dab4079
author Alexander Afanasyev <aa@cs.fiu.edu> Fri Jun 29 18:18:02 2018 -0400
committer Alexander Afanasyev <aa@cs.fiu.edu> Fri Jun 29 18:18:02 2018 -0400
tree d7aca09351e2d91368bf9992a1bb3b0be3bc710a
parent ea963953067d15ba0914666e4dfa0ba522311b33

encryptor: Continuosly retry fetching KEK forever

With this change, Encryptor will continue to retry fetching KEK until
success.  Each failed attempt will be notified to application via
onFailure callback supplied during Encryptor construction.

Change-Id: I48017b5d25bb77d9f7cfb45b21a9816fb99c33dd

src/encryptor.cpp

diff --git a/src/encryptor.cpp b/src/encryptor.cpp
index 26b9a73..0472e1e 100644
--- a/src/encryptor.cpp
+++ b/src/encryptor.cpp
@@ -38,11 +38,13 @@
   , m_ckBits{AES_KEY_SIZE}
   , m_ckDataSigningInfo{std::move(ckDataSigningInfo)}
   , m_isKekRetrievalInProgress(false)
+  , m_onFailure(onFailure)
   , m_ckRegId{nullptr}
   , m_keyChain{keyChain}
   , m_face{face}
+  , m_scheduler{face.getIoService()}
 {
-  regenerateCk(onFailure);
+  regenerateCk();
 
   auto serveFromIms = [this] (const Name& prefix, const Interest& interest) {
     auto data = m_ims.find(interest);
@@ -72,31 +74,42 @@
 }
 
 void
-Encryptor::regenerateCk(const ErrorCallback& onFailure)
+Encryptor::retryFetchingKek()
+{
+  if (m_isKekRetrievalInProgress) {
+    return;
+  }
+
+  NDN_LOG_DEBUG("Retrying fetching of KEK");
+  m_isKekRetrievalInProgress = true;
+  fetchKekAndPublishCkData([&] {
+      NDN_LOG_DEBUG("KEK retrieved and published");
+      m_isKekRetrievalInProgress = false;
+    },
+    [=] (const ErrorCode& code, const std::string& msg) {
+      NDN_LOG_ERROR("Failed to retrieved KEK: " + msg);
+      m_isKekRetrievalInProgress = false;
+      m_onFailure(code, msg);
+    },
+    N_RETRIES);
+}
+
+void
+Encryptor::regenerateCk()
 {
   m_ckName = m_ckPrefix;
   m_ckName
     .append(CK)
     .appendVersion(); // version = ID of CK
-  random::generateSecureBytes(m_ckBits.data(), m_ckBits.size());
-
   NDN_LOG_DEBUG("Generating new CK: " << m_ckName);
+  random::generateSecureBytes(m_ckBits.data(), m_ckBits.size());
 
   // one implication: if CK updated before KEK fetched, KDK for the old CK will not be published
   if (!m_kek) {
-    m_isKekRetrievalInProgress = true;
-    fetchKekAndPublishCkData([&] {
-        NDN_LOG_DEBUG("KEK retrieved and published");
-        m_isKekRetrievalInProgress = false;
-      },
-      [&] (const ErrorCode&, const std::string& msg) {
-        NDN_LOG_ERROR("Failed to retrieved KEK: " + msg);
-        m_isKekRetrievalInProgress = false;
-      },
-      N_RETRIES);
+    retryFetchingKek();
   }
   else {
-    makeAndPublishCkData(onFailure);
+    makeAndPublishCkData(m_onFailure);
   }
 }
 
@@ -145,9 +158,20 @@
                            },
                            [=] (const Interest& i, const lp::Nack& nack) {
                              m_kekPendingInterest = nullptr;
-                             onFailure(ErrorCode::KekRetrievalFailure,
-                                       "Retrieval of KEK [" + i.getName().toUri() + "] failed. "
-                                       "Got NACK (" + boost::lexical_cast<std::string>(nack.getReason()) + ")");
+                             if (nTriesLeft > 1) {
+                               m_scheduler.scheduleEvent(RETRY_DELAY_AFTER_NACK, [=] {
+                                   fetchKekAndPublishCkData(onReady, onFailure, nTriesLeft - 1);
+                                 });
+                             }
+                             else {
+                               onFailure(ErrorCode::KekRetrievalFailure,
+                                         "Retrieval of KEK [" + i.getName().toUri() + "] failed. "
+                                         "Got NACK (" + boost::lexical_cast<std::string>(nack.getReason()) + ")");
+                               NDN_LOG_DEBUG("Scheduling retry from NACK");
+                               m_scheduler.scheduleEvent(RETRY_DELAY_KEK_RETRIEVAL, [=] {
+                                   retryFetchingKek();
+                                 });
+                             }
                            },
                            [=] (const Interest& i) {
                              m_kekPendingInterest = nullptr;
@@ -157,6 +181,10 @@
                              else {
                                onFailure(ErrorCode::KekRetrievalTimeout,
                                          "Retrieval of KEK [" + i.getName().toUri() + "] timed out");
+                               NDN_LOG_DEBUG("Scheduling retry after all timeouts");
+                               m_scheduler.scheduleEvent(RETRY_DELAY_KEK_RETRIEVAL, [=] {
+                                   retryFetchingKek();
+                                 });
                              }
                            });
 }