Check amendment block status and update w/ ledgers:

Check and modify amendment blocked status with each new ledger (provided
by @wilsonianb). Honor blocked status in certain RPC commands and when
deciding whether to propose/validate.

Fixes: RIPD-1479
Fixes: RIPD-1447

Release Notes
-------------

This resolves an issue whereby an amendment blocked server would still
serve some RPC requests that are unreliable in blocked state and would
continue to publish validations.

src/ripple/app/consensus/RCLConsensus.cpp

@@ -934,9 +934,12 @@ RCLConsensus::peerProposal(
 bool
 RCLConsensus::Adaptor::preStartRound(RCLCxLedger const & prevLgr)
 {
-    // We have a key, and we have some idea what the ledger is
+    // We have a key, we have some idea what the ledger is, and we are not
+    // amendment blocked
     validating_ =
-        !app_.getOPs().isNeedNetworkLedger() && (valPublic_.size() != 0);
+        !app_.getOPs().isNeedNetworkLedger() &&
+        (valPublic_.size() != 0) &&
+        !app_.getOPs().isAmendmentBlocked();
 
     if (validating_)
     {

src/ripple/app/ledger/impl/LedgerMaster.cpp

@@ -227,6 +227,13 @@ LedgerMaster::setValidLedger(
     app_.getSHAMapStore().onLedgerClosed (getValidatedLedger());
     mLedgerHistory.validatedLedger (l);
     app_.getAmendmentTable().doValidatedLedger (l);
+    if (!app_.getOPs().isAmendmentBlocked() &&
+        app_.getAmendmentTable().hasUnsupportedEnabled ())
+    {
+        JLOG (m_journal.error()) <<
+            "One or more unsupported amendments activated: server blocked.";
+        app_.getOPs().setAmendmentBlocked();
+    }
 }
 
 void

src/ripple/app/misc/AmendmentTable.h

@@ -47,6 +47,14 @@ public:
     virtual bool isEnabled (uint256 const& amendment) = 0;
     virtual bool isSupported (uint256 const& amendment) = 0;
 
+    /**
+     * @brief returns true if one or more amendments on the network
+     * have been enabled that this server does not support
+     *
+     * @return true if an unsupported feature is enabled on the network
+     */
+    virtual bool hasUnsupportedEnabled () = 0;
+
     virtual Json::Value getJson (int) = 0;
 
     /** Returns a Json::objectValue. */

src/ripple/app/misc/impl/AmendmentTable.cpp

@@ -157,6 +157,9 @@ protected:
     // we haven't participated in one yet.
     std::unique_ptr <AmendmentSet> lastVote_;
 
+    // True if an unsupported amendment is enabled
+    bool unsupportedEnabled_;
+
     beast::Journal j_;
 
     // Finds or creates state
@@ -187,6 +190,8 @@ public:
     bool isEnabled (uint256 const& amendment) override;
     bool isSupported (uint256 const& amendment) override;
 
+    bool hasUnsupportedEnabled () override;
+
     Json::Value getJson (int) override;
     Json::Value getJson (uint256 const&) override;
 
@@ -222,6 +227,7 @@ AmendmentTableImpl::AmendmentTableImpl (
     : lastUpdateSeq_ (0)
     , majorityTime_ (majorityTime)
     , majorityFraction_ (majorityFraction)
+    , unsupportedEnabled_ (false)
     , j_ (journal)
 {
     assert (majorityFraction_ != 0);
@@ -340,6 +346,14 @@ AmendmentTableImpl::enable (uint256 const& amendment)
         return false;
 
     s->enabled = true;
+
+    if (! s->supported)
+    {
+        JLOG (j_.error()) <<
+            "Unsupported amendment " << amendment << " activated.";
+        unsupportedEnabled_ = true;
+    }
+
     return true;
 }
 
@@ -372,6 +386,13 @@ AmendmentTableImpl::isSupported (uint256 const& amendment)
     return s && s->supported;
 }
 
+bool
+AmendmentTableImpl::hasUnsupportedEnabled ()
+{
+    std::lock_guard <std::mutex> sl (mutex_);
+    return unsupportedEnabled_;
+}
+
 std::vector <uint256>
 AmendmentTableImpl::doValidation (
     std::set<uint256> const& enabled)
@@ -523,10 +544,8 @@ AmendmentTableImpl::doValidatedLedger (
     LedgerIndex ledgerSeq,
     std::set<uint256> const& enabled)
 {
-    std::lock_guard <std::mutex> sl (mutex_);
-
-    for (auto& e : amendmentMap_)
-        e.second.enabled = (enabled.count (e.first) != 0);
+    for (auto& e : enabled)
+        enable(e);
 }
 
 void

src/ripple/protocol/ErrorCodes.h

@@ -51,6 +51,7 @@ enum error_code_i
     rpcHIGH_FEE,
     rpcNOT_ENABLED,
     rpcNOT_READY,
+    rpcAMENDMENT_BLOCKED,
 
     // Networking
     rpcNO_CLOSED,

src/ripple/protocol/impl/ErrorCodes.cpp

@@ -53,6 +53,7 @@ public:
         add (rpcACT_EXISTS,            "actExists",         "Account already exists.");
         add (rpcACT_MALFORMED,         "actMalformed",      "Account malformed.");
         add (rpcACT_NOT_FOUND,         "actNotFound",       "Account not found.");
+        add (rpcAMENDMENT_BLOCKED,     "amendmentBlocked",  "Amendment blocked, need upgrade.");
         add (rpcATX_DEPRECATED,        "deprecated",        "Use the new API or specify a ledger range.");
         add (rpcBAD_BLOB,              "badBlob",           "Blob must be a non-empty hex string.");
         add (rpcBAD_FEATURE,           "badFeature",        "Feature unknown or invalid.");

src/ripple/rpc/impl/RPCHandler.cpp

@@ -157,6 +157,13 @@ error_code_i fillHandler (Context& context,
         return rpcNO_NETWORK;
     }
 
+    if (context.app.getOPs().isAmendmentBlocked() &&
+         (handler->condition_ & NEEDS_CURRENT_LEDGER ||
+          handler->condition_ & NEEDS_CLOSED_LEDGER))
+    {
+        return rpcAMENDMENT_BLOCKED;
+    }
+
     if (!context.app.config().standalone() &&
         handler->condition_ & NEEDS_CURRENT_LEDGER)
     {