Added GetPeerSnapshot block query:

This change enables retrieval of big ledger peers. This data can be
saved and loaded later, and used by the network layer
to facilitate syncing up a node from a fresh or stale state.

ouroboros-consensus-cardano/src/shelley/Ouroboros/Consensus/Shelley/Ledger/NetworkProtocolVersion.hs

@@ -37,6 +37,9 @@ data ShelleyNodeToClientVersion =
 
     -- | New queries introduced: GetConstitutionHash, GetFilteredVoteDelegatees
   | ShelleyNodeToClientVersion8
+
+    -- | New queries introduced: GetPeerSnapshot
+  | ShelleyNodeToClientVersion9
   deriving (Show, Eq, Ord, Enum, Bounded)
 
 instance HasNetworkProtocolVersion (ShelleyBlock proto era) where
@@ -63,6 +66,7 @@ instance SupportedNetworkProtocolVersion (ShelleyBlock proto era) where
       , (NodeToClientV_14, ShelleyNodeToClientVersion6)
       , (NodeToClientV_15, ShelleyNodeToClientVersion7)
       , (NodeToClientV_16, ShelleyNodeToClientVersion8)
+      , (NodeToClientV_16, ShelleyNodeToClientVersion9)
       ]
 
   latestReleasedNodeVersion = latestReleasedNodeVersionDefault

ouroboros-consensus-cardano/src/shelley/Ouroboros/Consensus/Shelley/Ledger/Query.hs

@@ -74,6 +74,7 @@ import           Ouroboros.Consensus.Config
 import           Ouroboros.Consensus.HeaderValidation
 import           Ouroboros.Consensus.Ledger.Extended
 import           Ouroboros.Consensus.Ledger.Query
+import           Ouroboros.Consensus.Ledger.SupportsPeerSelection
 import           Ouroboros.Consensus.Protocol.Abstract (ChainDepState)
 import           Ouroboros.Consensus.Shelley.Eras (EraCrypto)
 import qualified Ouroboros.Consensus.Shelley.Eras as SE
@@ -87,6 +88,8 @@ import           Ouroboros.Consensus.Shelley.Protocol.Abstract (ProtoCrypto)
 import           Ouroboros.Consensus.Util (ShowProxy (..))
 import           Ouroboros.Network.Block (Serialised (..), decodePoint,
                      encodePoint, mkSerialised)
+import           Ouroboros.Network.PeerSelection.LedgerPeers.Type
+import           Ouroboros.Network.PeerSelection.LedgerPeers.Util
 
 {-------------------------------------------------------------------------------
   QueryLedger
@@ -283,6 +286,14 @@ data instance BlockQuery (ShelleyBlock proto era) :: Type -> Type where
     => Set (SL.Credential 'SL.Staking (EraCrypto era))
     -> BlockQuery (ShelleyBlock proto era) (VoteDelegatees (EraCrypto era))
 
+  -- | Obtain a snapshot of big ledger peers. CLI can serialize these,
+  -- and if made available to the node by topology configuration,
+  -- the diffusion layer can use these peers when syncing up from some
+  -- fresh or stale ledger state - especially useful for Genesis mode
+  GetPeerSnapshot
+    :: LedgerSupportsPeerSelection (ShelleyBlock proto era)
+    => BlockQuery (ShelleyBlock proto era) LedgerPeerSnapshot
+
   -- WARNING: please add new queries to the end of the list and stick to this
   -- order in all other pattern matches on queries. This helps in particular
   -- with the en/decoders, as we want the CBOR tags to be ordered.
@@ -434,6 +445,12 @@ instance (ShelleyCompatible proto era, ProtoCrypto proto ~ crypto)
           SL.queryCommitteeMembersState coldCreds hotCreds statuses st
         GetFilteredVoteDelegatees stakeCreds ->
           getFilteredVoteDelegatees st stakeCreds
+        GetPeerSnapshot ->
+          let slot = shelleyTipSlotNo <$> shelleyLedgerTip lst
+              second f (a, b) = (a, f b)
+              ledgerPeers = second (fmap stakePoolRelayAccessPoint) <$> getPeers lst
+              bigLedgerPeers = accBigPoolStake ledgerPeers
+          in LedgerPeerSnapshot (slot, bigLedgerPeers)
     where
       lcfg    = configLedger $ getExtLedgerCfg cfg
       globals = shelleyLedgerGlobals lcfg
@@ -585,6 +602,8 @@ instance SameDepIndex (BlockQuery (ShelleyBlock proto era)) where
     | otherwise
     = Nothing
   sameDepIndex GetFilteredVoteDelegatees {} _ = Nothing
+  sameDepIndex GetPeerSnapshot GetPeerSnapshot = Just Refl
+  sameDepIndex GetPeerSnapshot _ = Nothing
 
 deriving instance Eq   (BlockQuery (ShelleyBlock proto era) result)
 deriving instance Show (BlockQuery (ShelleyBlock proto era) result)
@@ -620,6 +639,7 @@ instance ShelleyCompatible proto era => ShowQuery (BlockQuery (ShelleyBlock prot
       GetDRepStakeDistr {}                       -> show
       GetCommitteeMembersState {}                -> show
       GetFilteredVoteDelegatees {}               -> show
+      GetPeerSnapshot                            -> show
 
 -- | Is the given query supported by the given 'ShelleyNodeToClientVersion'?
 querySupportedVersion :: BlockQuery (ShelleyBlock proto era) result -> ShelleyNodeToClientVersion -> Bool
@@ -653,6 +673,7 @@ querySupportedVersion = \case
     GetDRepStakeDistr {}                       -> (>= v8)
     GetCommitteeMembersState {}                -> (>= v8)
     GetFilteredVoteDelegatees {}               -> (>= v8)
+    GetPeerSnapshot                            -> (>= v9)
     -- WARNING: when adding a new query, a new @ShelleyNodeToClientVersionX@
     -- must be added. See #2830 for a template on how to do this.
   where
@@ -664,6 +685,7 @@ querySupportedVersion = \case
     v6 = ShelleyNodeToClientVersion6
     v7 = ShelleyNodeToClientVersion7
     v8 = ShelleyNodeToClientVersion8
+    v9 = ShelleyNodeToClientVersion9
 
 {-------------------------------------------------------------------------------
   Auxiliary
@@ -774,9 +796,11 @@ encodeShelleyQuery query = case query of
       CBOR.encodeListLen 4 <> CBOR.encodeWord8 27 <> toCBOR coldCreds <> toCBOR hotCreds <> LC.toEraCBOR @era statuses
     GetFilteredVoteDelegatees stakeCreds ->
       CBOR.encodeListLen 2 <> CBOR.encodeWord8 28 <> LC.toEraCBOR @era stakeCreds
+    GetPeerSnapshot ->
+      CBOR.encodeListLen 1 <> CBOR.encodeWord8 29
 
 decodeShelleyQuery ::
-     forall era proto. ShelleyBasedEra era
+     forall era proto . (ShelleyBasedEra era, LedgerSupportsPeerSelection (ShelleyBlock proto era))
   => forall s. Decoder s (SomeSecond BlockQuery (ShelleyBlock proto era))
 decodeShelleyQuery = do
     len <- CBOR.decodeListLen
@@ -830,6 +854,7 @@ decodeShelleyQuery = do
         return $ SomeSecond $ GetCommitteeMembersState coldCreds hotCreds statuses
       (2, 28) -> requireCG $ do
         SomeSecond . GetFilteredVoteDelegatees <$> LC.fromEraCBOR @era
+      (1, 29) ->             return $ SomeSecond GetPeerSnapshot
       _       -> failmsg "invalid"
 
 encodeShelleyResult ::
@@ -866,6 +891,7 @@ encodeShelleyResult v query = case query of
     GetDRepStakeDistr {}                       -> LC.toEraCBOR @era
     GetCommitteeMembersState {}                -> LC.toEraCBOR @era
     GetFilteredVoteDelegatees {}               -> LC.toEraCBOR @era
+    GetPeerSnapshot                            -> toCBOR
 
 decodeShelleyResult ::
      forall proto era result. ShelleyCompatible proto era
@@ -902,6 +928,7 @@ decodeShelleyResult v query = case query of
     GetDRepStakeDistr {}                       -> LC.fromEraCBOR @era
     GetCommitteeMembersState {}                -> LC.fromEraCBOR @era
     GetFilteredVoteDelegatees {}               -> LC.fromEraCBOR @era
+    GetPeerSnapshot                            -> fromCBOR
 
 currentPParamsEnDecoding ::
      forall era s.

ouroboros-consensus-diffusion/CHANGELOG.md

@@ -13,6 +13,10 @@ NOTE: version jumps from `0.13.0.0` to `0.15.0.0` because `0.14.0.0` was created
   `LowLevelRounNodeArgs` and `NodeKernel` records hold
   `PublicPeerSelectionState` variable.
 
+### Non-Breaking
+
+- Added `GetPeerSnapshot` block query
+
 <a id='changelog-0.13.0.0'></a>
 ## 0.13.0.0 — 2024-04-03