feat!: v20 BIP9 fork (#5121)

## Issue being fixed or feature implemented


## What was done?
Added v20 BIP9 style fork structure along with utility functions. 
Since several features coming depending on that fork status, we needed
to group them into one

## How Has This Been Tested?


## Breaking Changes


## Checklist:
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [ ] I have made corresponding changes to the documentation

**For repository code-owners and collaborators only**
- [x] I have assigned this pull request to a milestone

src/chainparams.cpp

@@ -245,6 +245,15 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nThresholdMin = 2420;         // 60% of 4032
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nFalloffCoeff = 5;            // this corresponds to 10 periods
 
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].bit = 9;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nStartTime = 19999999999;     // TODO: To be determined later
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nTimeout = 999999999999ULL;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize = 4032;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdStart = 3226;       // 80% of 4032
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdMin = 2420;         // 60% of 4032
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nFalloffCoeff = 5;            // this corresponds to 10 periods
+
+
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x0000000000000000000000000000000000000000000082094584a23266cbb5f8"); // 1850400
 
@@ -484,6 +493,14 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nThresholdMin = 60;           // 60% of 100
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nFalloffCoeff = 5;            // this corresponds to 10 periods
 
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].bit = 9;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nStartTime = 19999999999;     // TODO: To be determined later
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nTimeout = 999999999999ULL;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize = 100;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdStart = 80;         // 80% of 100
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdMin = 60;           // 60% of 100
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nFalloffCoeff = 5;            // this corresponds to 10 periods
+
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000000000000002d68cb6c090031f"); // 864000
 
@@ -696,6 +713,14 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nThresholdMin = 60;   // 60% of 100
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nFalloffCoeff = 5;     // this corresponds to 10 periods
 
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].bit = 9;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nStartTime = 1661990400; // Sep 1st, 2022
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nTimeout = 999999999999ULL;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize = 120;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdStart = 80; // 80% of 100
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdMin = 60;   // 60% of 100
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nFalloffCoeff = 5;     // this corresponds to 10 periods
+
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x000000000000000000000000000000000000000000000000000000000000000");
 
@@ -959,6 +984,14 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nThresholdMin = 180;   // 60% of 300
         consensus.vDeployments[Consensus::DEPLOYMENT_V19].nFalloffCoeff = 5;     // this corresponds to 10 periods
 
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].bit = 9;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nStartTime = 0;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nTimeout = 999999999999ULL;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nWindowSize = 320;
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdStart = 240; // 80% of 300
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nThresholdMin = 180;   // 60% of 300
+        consensus.vDeployments[Consensus::DEPLOYMENT_V20].nFalloffCoeff = 5;     // this corresponds to 10 periods
+
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x00");
 

src/consensus/params.h

@@ -23,7 +23,8 @@ enum DeploymentPos {
     DEPLOYMENT_REALLOC, // Deployment of Block Reward Reallocation
     DEPLOYMENT_DIP0020, // Deployment of DIP0020, DIP0021 and LMQ_100_67 quorums
     DEPLOYMENT_DIP0024, // Deployment of DIP0024 (Quorum Rotation) and decreased governance proposal fee
-    DEPLOYMENT_V19,     // Deployment of Basic BLS, AssetLocks, EHF
+    DEPLOYMENT_V19,     // Deployment of Basic BLS, AssetLocks
+    DEPLOYMENT_V20,     // Deployment of EHF, LLMQ Randomness Beacon
     // NOTE: Also add new deployments to VersionBitsDeploymentInfo in versionbits.cpp
     MAX_VERSION_BITS_DEPLOYMENTS
 };

src/llmq/utils.cpp

@@ -671,6 +671,14 @@ const CBlockIndex* V19ActivationIndex(const CBlockIndex* pindex)
     return pindex->GetAncestor(nHeight);
 }
 
+bool IsV20Active(const CBlockIndex* pindex)
+{
+    assert(pindex);
+
+    LOCK(cs_llmq_vbc);
+    return VersionBitsState(pindex, Params().GetConsensus(), Consensus::DEPLOYMENT_V20, llmq_versionbitscache) == ThresholdState::ACTIVE;
+}
+
 bool IsInstantSendLLMQTypeShared()
 {
     if (Params().GetConsensus().llmqTypeInstantSend == Params().GetConsensus().llmqTypeChainLocks ||

src/llmq/utils.h

@@ -85,6 +85,7 @@ Consensus::LLMQType GetInstantSendLLMQType(bool deterministic);
 bool IsDIP0024Active(const CBlockIndex* pindex);
 bool IsV19Active(const CBlockIndex* pindex);
 const CBlockIndex* V19ActivationIndex(const CBlockIndex* pindex);
+bool IsV20Active(const CBlockIndex* pindex);
 
 /// Returns the state of `-llmq-data-recovery`
 bool QuorumDataRecoveryEnabled();

src/versionbitsinfo.cpp

@@ -56,5 +56,10 @@ const struct VBDeploymentInfo VersionBitsDeploymentInfo[Consensus::MAX_VERSION_B
         /*.name =*/"v19",
         /*.gbt_force =*/true,
         /*.check_mn_protocol =*/false,
+    },
+    {
+        /*.name =*/"v20",
+        /*.gbt_force =*/true,
+        /*.check_mn_protocol =*/false,
     }
 };