Harden validations:

This commit introduces the "HardenedValidations" amendment which,
if enabled, allows validators to include additional information in
their validations that can increase the robustness of consensus.

Specifically, the commit introduces a new optional field that can
be set in validation messages can be used to attest to the hash of
the latest ledger that a validator considers to be fully validated.

Additionally, the commit leverages the previously introduced "cookie"
field to improve the robustness of the network by making it possible
for servers to automatically detect accidental misconfiguration which
results in two or more validators using the same validation key.

src/ripple/protocol/impl/Feature.cpp

@@ -130,7 +130,7 @@ detail::supportedAmendments()
         "fixQualityUpperBound",
         "RequireFullyCanonicalSig",
         "fix1781",
-    };
+        "HardenedValidations"};
     return supported;
 }
 
@@ -187,6 +187,8 @@ uint256 const fixQualityUpperBound =
 uint256 const featureRequireFullyCanonicalSig =
     *getRegisteredFeature("RequireFullyCanonicalSig");
 uint256 const fix1781 = *getRegisteredFeature("fix1781");
+uint256 const featureHardenedValidations =
+    *getRegisteredFeature("HardenedValidations");
 
 // The following amendments have been active for at least two years.
 // Their pre-amendment code has been removed.

src/ripple/protocol/impl/SField.cpp

@@ -168,6 +168,7 @@ SF_U256 const sfDigest(access, STI_HASH256, 21, "Digest");
 SF_U256 const sfPayChannel(access, STI_HASH256, 22, "Channel");
 SF_U256 const sfConsensusHash(access, STI_HASH256, 23, "ConsensusHash");
 SF_U256 const sfCheckID(access, STI_HASH256, 24, "CheckID");
+SF_U256 const sfValidatedHash(access, STI_HASH256, 25, "ValidatedHash");
 
 // currency amount (common)
 SF_Amount const sfAmount(access, STI_AMOUNT, 1, "Amount");

src/ripple/protocol/impl/STValidation.cpp

@@ -25,68 +25,32 @@
 
 namespace ripple {
 
-STValidation::STValidation(
-    uint256 const& ledgerHash,
-    std::uint32_t ledgerSeq,
-    uint256 const& consensusHash,
-    NetClock::time_point signTime,
-    PublicKey const& publicKey,
-    SecretKey const& secretKey,
-    NodeID const& nodeID,
-    bool isFull,
-    FeeSettings const& fees,
-    std::vector<uint256> const& amendments)
-    : STObject(getFormat(), sfValidation), mNodeID(nodeID), mSeen(signTime)
+SOTemplate const&
+STValidation::validationFormat()
 {
-    // This is our own public key and it should always be valid.
-    if (!publicKeyType(publicKey))
-        LogicError("Invalid validation public key");
-    assert(mNodeID.isNonZero());
-    setFieldH256(sfLedgerHash, ledgerHash);
-    setFieldH256(sfConsensusHash, consensusHash);
-    setFieldU32(sfSigningTime, signTime.time_since_epoch().count());
+    // We can't have this be a magic static at namespace scope because
+    // it relies on the SField's below being initialized, and we can't
+    // guarantee the initialization order.
+    static SOTemplate const format{
+        {sfFlags, soeREQUIRED},
+        {sfLedgerHash, soeREQUIRED},
+        {sfLedgerSequence, soeOPTIONAL},
+        {sfCloseTime, soeOPTIONAL},
+        {sfLoadFee, soeOPTIONAL},
+        {sfAmendments, soeOPTIONAL},
+        {sfBaseFee, soeOPTIONAL},
+        {sfReserveBase, soeOPTIONAL},
+        {sfReserveIncrement, soeOPTIONAL},
+        {sfSigningTime, soeREQUIRED},
+        {sfSigningPubKey, soeREQUIRED},
+        {sfSignature, soeOPTIONAL},
+        {sfConsensusHash, soeOPTIONAL},
+        {sfCookie, soeDEFAULT},
+        {sfValidatedHash, soeOPTIONAL},
+    };
 
-    setFieldVL(sfSigningPubKey, publicKey.slice());
-    if (isFull)
-        setFlag(kFullFlag);
-
-    setFieldU32(sfLedgerSequence, ledgerSeq);
-
-    if (fees.loadFee)
-        setFieldU32(sfLoadFee, *fees.loadFee);
-
-    // IF any of the values are out of the valid range, don't send a value.
-    // They should not be an issue, though, because the voting
-    // process (FeeVoteImpl) ignores any out of range values.
-    if (fees.baseFee)
-    {
-        if (auto const v = fees.baseFee->dropsAs<std::uint64_t>())
-            setFieldU64(sfBaseFee, *v);
-    }
-
-    if (fees.reserveBase)
-    {
-        if (auto const v = fees.reserveBase->dropsAs<std::uint32_t>())
-            setFieldU32(sfReserveBase, *v);
-    }
-
-    if (fees.reserveIncrement)
-    {
-        if (auto const v = fees.reserveIncrement->dropsAs<std::uint32_t>())
-            setFieldU32(sfReserveIncrement, *v);
-    }
-
-    if (!amendments.empty())
-        setFieldV256(sfAmendments, STVector256(sfAmendments, amendments));
-
-    setFlag(vfFullyCanonicalSig);
-
-    auto const signingHash = getSigningHash();
-    setFieldVL(
-        sfSignature, signDigest(getSignerPublic(), secretKey, signingHash));
-
-    setTrusted();
-}
+    return format;
+};
 
 uint256
 STValidation::getSigningHash() const
@@ -115,7 +79,7 @@ STValidation::getSignTime() const
 NetClock::time_point
 STValidation::getSeenTime() const
 {
-    return mSeen;
+    return seenTime_;
 }
 
 bool
@@ -148,7 +112,7 @@ STValidation::getSignerPublic() const
 bool
 STValidation::isFull() const
 {
-    return (getFlags() & kFullFlag) != 0;
+    return (getFlags() & vfFullValidation) != 0;
 }
 
 Blob
@@ -165,32 +129,4 @@ STValidation::getSerialized() const
     return s.peekData();
 }
 
-SOTemplate const&
-STValidation::getFormat()
-{
-    struct FormatHolder
-    {
-        SOTemplate format{
-            {sfFlags, soeREQUIRED},
-            {sfLedgerHash, soeREQUIRED},
-            {sfLedgerSequence, soeOPTIONAL},
-            {sfCloseTime, soeOPTIONAL},
-            {sfLoadFee, soeOPTIONAL},
-            {sfAmendments, soeOPTIONAL},
-            {sfBaseFee, soeOPTIONAL},
-            {sfReserveBase, soeOPTIONAL},
-            {sfReserveIncrement, soeOPTIONAL},
-            {sfSigningTime, soeREQUIRED},
-            {sfSigningPubKey, soeREQUIRED},
-            {sfSignature, soeOPTIONAL},
-            {sfConsensusHash, soeOPTIONAL},
-            {sfCookie, soeOPTIONAL},
-        };
-    };
-
-    static const FormatHolder holder;
-
-    return holder.format;
-}
-
 }  // namespace ripple