stake-pool: Add DecreaseAdditionalValidatorStake instruction

stake-pool/program/src/instruction.rs

@@ -4,8 +4,9 @@
 
 use {
     crate::{
-        find_deposit_authority_program_address, find_stake_program_address,
-        find_transient_stake_program_address, find_withdraw_authority_program_address,
+        find_deposit_authority_program_address, find_ephemeral_stake_program_address,
+        find_stake_program_address, find_transient_stake_program_address,
+        find_withdraw_authority_program_address,
         state::{Fee, FeeType, StakePool, ValidatorList},
         MAX_VALIDATORS_TO_UPDATE,
     },
@@ -401,6 +402,37 @@ pub enum StakePoolInstruction {
         /// URI of the uploaded metadata of the spl-token
         uri: String,
     },
+
+    /// (Staker only) Decrease active stake again from a validator, eventually moving it to the reserve
+    ///
+    /// Works regardless if the transient stake account already exists.
+    ///
+    /// Internally, this instruction splits a validator stake account into an
+    /// ephemeral stake account, deactivates it, then merges or splits it into
+    /// the transient stake account delegated to the appropriate validator.
+    ///
+    ///  The amount of lamports to move must be at least rent-exemption plus
+    /// `max(crate::MINIMUM_ACTIVE_STAKE, solana_program::stake::tools::get_minimum_delegation())`.
+    ///
+    ///  0. `[]` Stake pool
+    ///  1. `[s]` Stake pool staker
+    ///  2. `[]` Stake pool withdraw authority
+    ///  3. `[w]` Validator list
+    ///  4. `[w]` Canonical stake account to split from
+    ///  5. `[w]` Uninitialized ephemeral stake account to receive stake
+    ///  6. `[w]` Transient stake account
+    ///  7. `[]` Clock sysvar
+    ///  8. '[]' Stake history sysvar
+    ///  9. `[]` System program
+    /// 10. `[]` Stake program
+    DecreaseAdditionalValidatorStake {
+        /// amount of lamports to split into the transient stake account
+        lamports: u64,
+        /// seed used to create transient stake account
+        transient_stake_seed: u64,
+        /// seed used to create ephemeral account.
+        ephemeral_stake_seed: u64,
+    },
 }
 
 /// Creates an 'initialize' instruction.
@@ -554,6 +586,47 @@ pub fn decrease_validator_stake(
     }
 }
 
+/// Creates `DecreaseAdditionalValidatorStake` instruction (rebalance from
+/// validator account to transient account)
+pub fn decrease_additional_validator_stake(
+    program_id: &Pubkey,
+    stake_pool: &Pubkey,
+    staker: &Pubkey,
+    stake_pool_withdraw_authority: &Pubkey,
+    validator_list: &Pubkey,
+    validator_stake: &Pubkey,
+    ephemeral_stake: &Pubkey,
+    transient_stake: &Pubkey,
+    lamports: u64,
+    transient_stake_seed: u64,
+    ephemeral_stake_seed: u64,
+) -> Instruction {
+    let accounts = vec![
+        AccountMeta::new_readonly(*stake_pool, false),
+        AccountMeta::new_readonly(*staker, true),
+        AccountMeta::new_readonly(*stake_pool_withdraw_authority, false),
+        AccountMeta::new(*validator_list, false),
+        AccountMeta::new(*validator_stake, false),
+        AccountMeta::new(*ephemeral_stake, false),
+        AccountMeta::new(*transient_stake, false),
+        AccountMeta::new_readonly(sysvar::clock::id(), false),
+        AccountMeta::new_readonly(sysvar::stake_history::id(), false),
+        AccountMeta::new_readonly(system_program::id(), false),
+        AccountMeta::new_readonly(stake::program::id(), false),
+    ];
+    Instruction {
+        program_id: *program_id,
+        accounts,
+        data: StakePoolInstruction::DecreaseAdditionalValidatorStake {
+            lamports,
+            transient_stake_seed,
+            ephemeral_stake_seed,
+        }
+        .try_to_vec()
+        .unwrap(),
+    }
+}
+
 /// Creates `IncreaseValidatorStake` instruction (rebalance from reserve account to
 /// transient account)
 pub fn increase_validator_stake(
@@ -762,6 +835,49 @@ pub fn decrease_validator_stake_with_vote(
     )
 }
 
+/// Create a `DecreaseAdditionalValidatorStake` instruction given an existing
+/// stake pool and vote account
+pub fn decrease_additional_validator_stake_with_vote(
+    program_id: &Pubkey,
+    stake_pool: &StakePool,
+    stake_pool_address: &Pubkey,
+    vote_account_address: &Pubkey,
+    lamports: u64,
+    validator_stake_seed: Option<NonZeroU32>,
+    transient_stake_seed: u64,
+    ephemeral_stake_seed: u64,
+) -> Instruction {
+    let pool_withdraw_authority =
+        find_withdraw_authority_program_address(program_id, stake_pool_address).0;
+    let (validator_stake_address, _) = find_stake_program_address(
+        program_id,
+        vote_account_address,
+        stake_pool_address,
+        validator_stake_seed,
+    );
+    let (ephemeral_stake_address, _) =
+        find_ephemeral_stake_program_address(program_id, stake_pool_address, ephemeral_stake_seed);
+    let (transient_stake_address, _) = find_transient_stake_program_address(
+        program_id,
+        vote_account_address,
+        stake_pool_address,
+        transient_stake_seed,
+    );
+    decrease_additional_validator_stake(
+        program_id,
+        stake_pool_address,
+        &stake_pool.staker,
+        &pool_withdraw_authority,
+        &stake_pool.validator_list,
+        &validator_stake_address,
+        &ephemeral_stake_address,
+        &transient_stake_address,
+        lamports,
+        transient_stake_seed,
+        ephemeral_stake_seed,
+    )
+}
+
 /// Creates `UpdateValidatorListBalance` instruction (update validator stake account balances)
 pub fn update_validator_list_balance(
     program_id: &Pubkey,

stake-pool/program/src/lib.rs

@@ -28,6 +28,9 @@ const AUTHORITY_WITHDRAW: &[u8] = b"withdraw";
 /// Seed for transient stake account
 const TRANSIENT_STAKE_SEED_PREFIX: &[u8] = b"transient";
 
+/// Seed for ephemeral stake account
+const EPHEMERAL_STAKE_SEED_PREFIX: &[u8] = b"ephemeral";
+
 /// Minimum amount of staked lamports required in a validator stake account to allow
 /// for merges without a mismatch on credits observed
 pub const MINIMUM_ACTIVE_STAKE: u64 = 1_000_000;
@@ -138,6 +141,22 @@ pub fn find_transient_stake_program_address(
     )
 }
 
+/// Generates the ephemeral program address for stake pool redelegation
+pub fn find_ephemeral_stake_program_address(
+    program_id: &Pubkey,
+    stake_pool_address: &Pubkey,
+    seed: u64,
+) -> (Pubkey, u8) {
+    Pubkey::find_program_address(
+        &[
+            EPHEMERAL_STAKE_SEED_PREFIX,
+            stake_pool_address.as_ref(),
+            &seed.to_le_bytes(),
+        ],
+        program_id,
+    )
+}
+
 solana_program::declare_id!("SPoo1Ku8WFXoNDMHPsrGSTSG1Y47rzgn41SLUNakuHy");
 
 #[cfg(test)]