From 05f961c77cc5fb5637207754f5d3e005a8d75605 Mon Sep 17 00:00:00 2001
From: Richard Holland <richard.holland@starstone.co.nz>
Date: Mon, 19 Dec 2022 16:45:13 +0000
Subject: [PATCH] first half of XPOP_HISTORY

---
 src/ripple/app/misc/NetworkOPs.cpp     | 34 ++++++++++++++++++++++++++
 src/ripple/core/Config.h               |  4 +++
 src/ripple/core/ConfigSections.h       |  1 +
 src/ripple/core/impl/Config.cpp        |  3 +++
 src/ripple/protocol/SystemParameters.h |  2 +-
 5 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/ripple/app/misc/NetworkOPs.cpp b/src/ripple/app/misc/NetworkOPs.cpp
index 2c9819f0b..587746392 100644
--- a/src/ripple/app/misc/NetworkOPs.cpp
+++ b/src/ripple/app/misc/NetworkOPs.cpp
@@ -79,6 +79,9 @@ namespace ripple {
 
 class NetworkOPsImp final : public NetworkOPs
 {
+    // ledger_seq -> validator key -> validation message
+    std::map<uint32_t, std::map<PublicKey, STValidation>> xpop_history;
+
     /**
      * Transaction with input flags and results to be applied in batches.
      */
@@ -2325,6 +2328,37 @@ NetworkOPsImp::recvValidation(
 
     handleNewValidation(app_, val, source);
 
+    // manage xpop validation history
+    if (app_.config().XPOP_HISTORY)
+    {
+        if (val->isTrusted())
+        {
+            uint32_t seq = val->getFieldU32(sfLedgerSequence);
+
+            if (xpop_history.find(seq) == xpop_history.end())
+                xpop_history.emplace(seq, std::map<PublicKey, STValidation>{});
+
+            xpop_history[seq].emplace(val->getSignerPublic(), *val);
+        }
+
+        uint32_t delete_threshold = 
+            app_.getLedgerMaster().getValidLedgerIndex() + 1 - *(app_.config().XPOP_HISTORY);
+
+        if (xpop_history.find(delete_threshold) != xpop_history.end())
+            xpop_history.erase(delete_threshold);
+
+        if (xpop_history.size() > *(app_.config().XPOP_HISTORY))
+        {
+            std::unordered_set<uint32_t> to_delete;
+            for (auto const& kp : xpop_history)
+                if (kp.first < delete_threshold)
+                    to_delete.emplace(kp.first);
+
+            for (uint32_t td: to_delete)
+                xpop_history.erase(td);
+        }
+    }
+
     pubValidation(val);
 
     // We will always relay trusted validations; if configured, we will
diff --git a/src/ripple/core/Config.h b/src/ripple/core/Config.h
index 2d440a1af..c7ec6f631 100644
--- a/src/ripple/core/Config.h
+++ b/src/ripple/core/Config.h
@@ -152,6 +152,10 @@ public:
     int RELAY_UNTRUSTED_VALIDATIONS = 1;
     int RELAY_UNTRUSTED_PROPOSALS = 0;
 
+    // The number of ledgers worth of valdiations to keep for the purpose
+    // of servicing xpop requests these are lost on restart
+    std::optional<uint32_t> XPOP_HISTORY;
+
     // True to ask peers not to relay current IP.
     bool PEER_PRIVATE = false;
     // peers_max is a legacy configuration, which is going to be replaced
diff --git a/src/ripple/core/ConfigSections.h b/src/ripple/core/ConfigSections.h
index ba0f209c0..41bee720c 100644
--- a/src/ripple/core/ConfigSections.h
+++ b/src/ripple/core/ConfigSections.h
@@ -101,6 +101,7 @@ struct ConfigSection
 #define SECTION_LEDGER_REPLAY "ledger_replay"
 #define SECTION_BETA_RPC_API "beta_rpc_api"
 #define SECTION_SWEEP_INTERVAL "sweep_interval"
+#define SECTION_XPOP_HISTORY "xpop_history"
 
 }  // namespace ripple
 
diff --git a/src/ripple/core/impl/Config.cpp b/src/ripple/core/impl/Config.cpp
index 9cdb17d4e..7024bb8e3 100644
--- a/src/ripple/core/impl/Config.cpp
+++ b/src/ripple/core/impl/Config.cpp
@@ -481,6 +481,9 @@ Config::loadFromString(std::string const& fileContents)
 
     std::string strTemp;
 
+    if (getSingleSection(secConfig, SECTION_XPOP_HISTORY, strTemp, j_))
+        XPOP_HISTORY = beast::lexicalCastThrow<bool>(strTemp);
+
     if (getSingleSection(secConfig, SECTION_PEER_PRIVATE, strTemp, j_))
         PEER_PRIVATE = beast::lexicalCastThrow<bool>(strTemp);
 
diff --git a/src/ripple/protocol/SystemParameters.h b/src/ripple/protocol/SystemParameters.h
index cd76970e9..91121022c 100644
--- a/src/ripple/protocol/SystemParameters.h
+++ b/src/ripple/protocol/SystemParameters.h
@@ -73,7 +73,7 @@ constexpr std::ratio<204, 256> preFixAmendmentMajorityCalcThreshold;
 constexpr std::ratio<80, 100> postFixAmendmentMajorityCalcThreshold;
 
 /** The minimum amount of time an amendment must hold a majority */
-constexpr std::chrono::seconds const defaultAmendmentMajorityTime = weeks{2};
+constexpr std::chrono::seconds const defaultAmendmentMajorityTime = days{5};
 
 }  // namespace ripple