Composable flash loan implementation

token-lending/cli/Cargo.toml

@@ -10,12 +10,12 @@ version = "0.1.0"
 
 [dependencies]
 clap = "=2.34.0"
-solana-clap-utils = "=1.7.12"
-solana-cli-config = "=1.7.12"
-solana-client = "=1.7.12"
-solana-logger = "=1.7.12"
-solana-sdk = "=1.7.12"
-solana-program = "=1.7.12"
+solana-clap-utils = "=1.8.14"
+solana-cli-config = "=1.8.14"
+solana-client = "=1.8.14"
+solana-logger = "=1.8.14"
+solana-sdk = "=1.8.14"
+solana-program = "=1.8.14"
 spl-token-lending = { path="../program", features = [ "no-entrypoint" ] }
 spl-token = { version = "3.2.0", features=["no-entrypoint"] }
 

token-lending/program/Cargo.toml

@@ -16,7 +16,7 @@ arrayref = "0.3.6"
 bytemuck = "1.5.1"
 num-derive = "0.3"
 num-traits = "0.2"
-solana-program = "=1.7.12"
+solana-program = "=1.8.14"
 spl-token = { version = "3.2.0", features=["no-entrypoint"] }
 switchboard-program = "0.2.0"
 thiserror = "1.0"
@@ -27,8 +27,8 @@ assert_matches = "1.5.0"
 base64 = "0.13"
 log = "0.4.14"
 proptest = "1.0"
-solana-program-test = "=1.7.12"
-solana-sdk = "=1.7.12"
+solana-program-test = "=1.8.14"
+solana-sdk = "=1.8.14"
 serde = "1.0"
 serde_yaml = "0.8"
 

token-lending/program/src/error.rs

@@ -159,10 +159,31 @@ pub enum LendingError {
     /// Not enough liquidity after flash loan
     #[error("Not enough liquidity after flash loan")]
     NotEnoughLiquidityAfterFlashLoan,
+
     // 45
     /// Null oracle config
     #[error("Null oracle config")]
     NullOracleConfig,
+    /// No cpi flash borrows allowed
+    #[error("No cpi flash borrows allowed")]
+    FlashBorrowCpi,
+    /// No corresponding repay found for flash borrow
+    #[error("No corresponding repay found for flash borrow")]
+    NoFlashRepayFound,
+    /// Invalid flash repay found for borrow
+    #[error("Invalid repay found for flash borrow")]
+    InvalidFlashRepay,
+    /// No cpi flash repays allowed
+    #[error("No cpi flash repays allowed")]
+    FlashRepayCpi,
+
+    // 50
+    /// Multiple flash borrows not allowed in the same transaction
+    #[error("Multiple flash borrows not allowed in the same transaction")]
+    MultipleFlashBorrows,
+    /// Flash loans are disabled for this reserve
+    #[error("Flash loans are disabled for this reserve")]
+    FlashLoansDisabled,
 }
 
 impl From<LendingError> for ProgramError {

token-lending/program/src/instruction.rs

@@ -379,6 +379,45 @@ pub enum LendingInstruction {
         /// Reserve config to update to
         config: ReserveConfig,
     },
+
+    // 17
+    /// Flash borrow reserve liquidity
+    //
+    /// Accounts expected by this instruction:
+    ///
+    ///   0. `[writable]` Source liquidity token account.
+    ///   1. `[writable]` Destination liquidity token account.
+    ///   2. `[writable]` Reserve account.
+    ///   3. `[]` Lending market account.
+    ///   4. `[]` Derived lending market authority.
+    ///   5. `[]` Instructions sysvar.
+    ///   6. `[]` Token program id.
+    ///   7. `[]` Clock sysvar.
+    FlashBorrowReserveLiquidity {
+        /// Amount of liquidity to flash borrow
+        liquidity_amount: u64,
+    },
+
+    // 18
+    /// Flash repay reserve liquidity
+    //
+    /// Accounts expected by this instruction:
+    ///
+    ///   0. `[writable]` Source liquidity token account.
+    ///                     $authority can transfer $liquidity_amount.
+    ///   1. `[writable]` Destination liquidity token account.
+    ///   2. `[writable]` Flash loan fee receiver account.
+    ///                     Must match the reserve liquidity fee receiver.
+    ///   3. `[writable]` Host fee receiver.
+    ///   4. `[writable]` Reserve account.
+    ///   5. `[]` Lending market account.
+    ///   6. `[signer]` User transfer authority ($authority).
+    ///   7. `[]` Instructions sysvar.
+    ///   8. `[]` Token program id.
+    FlashRepayReserveLiquidity {
+        /// Amount of liquidity to flash repay
+        liquidity_amount: u64,
+    },
 }
 
 impl LendingInstruction {
@@ -514,6 +553,14 @@ impl LendingInstruction {
                     },
                 }
             }
+            17 => {
+                let (liquidity_amount, _rest) = Self::unpack_u64(rest)?;
+                Self::FlashBorrowReserveLiquidity { liquidity_amount }
+            }
+            18 => {
+                let (liquidity_amount, _rest) = Self::unpack_u64(rest)?;
+                Self::FlashRepayReserveLiquidity { liquidity_amount }
+            }
             _ => {
                 msg!("Instruction cannot be unpacked");
                 return Err(LendingError::InstructionUnpackError.into());
@@ -692,6 +739,14 @@ impl LendingInstruction {
                 buf.extend_from_slice(&config.borrow_limit.to_le_bytes());
                 buf.extend_from_slice(&config.fee_receiver.to_bytes());
             }
+            Self::FlashBorrowReserveLiquidity { liquidity_amount } => {
+                buf.push(17);
+                buf.extend_from_slice(&liquidity_amount.to_le_bytes());
+            }
+            Self::FlashRepayReserveLiquidity { liquidity_amount } => {
+                buf.push(18);
+                buf.extend_from_slice(&liquidity_amount.to_le_bytes());
+            }
         }
         buf
     }
@@ -1216,3 +1271,64 @@ pub fn update_reserve_config(
         data: LendingInstruction::UpdateReserveConfig { config }.pack(),
     }
 }
+
+/// Creates a 'FlashBorrowReserveLiquidity' instruction.
+#[allow(clippy::too_many_arguments)]
+pub fn flash_borrow_reserve_liquidity(
+    program_id: Pubkey,
+    liquidity_amount: u64,
+    source_liquidity_pubkey: Pubkey,
+    destination_liquidity_pubkey: Pubkey,
+    reserve_pubkey: Pubkey,
+    lending_market_pubkey: Pubkey,
+) -> Instruction {
+    let (lending_market_authority_pubkey, _bump_seed) = Pubkey::find_program_address(
+        &[&lending_market_pubkey.to_bytes()[..PUBKEY_BYTES]],
+        &program_id,
+    );
+
+    Instruction {
+        program_id,
+        accounts: vec![
+            AccountMeta::new(source_liquidity_pubkey, false),
+            AccountMeta::new(destination_liquidity_pubkey, false),
+            AccountMeta::new(reserve_pubkey, false),
+            AccountMeta::new_readonly(lending_market_pubkey, false),
+            AccountMeta::new_readonly(lending_market_authority_pubkey, false),
+            AccountMeta::new_readonly(sysvar::instructions::id(), false),
+            AccountMeta::new_readonly(spl_token::id(), false),
+            AccountMeta::new_readonly(sysvar::clock::id(), false),
+        ],
+        data: LendingInstruction::FlashBorrowReserveLiquidity { liquidity_amount }.pack(),
+    }
+}
+
+/// Creates a 'FlashRepayReserveLiquidity' instruction.
+#[allow(clippy::too_many_arguments)]
+pub fn flash_repay_reserve_liquidity(
+    program_id: Pubkey,
+    liquidity_amount: u64,
+    source_liquidity_pubkey: Pubkey,
+    destination_liquidity_pubkey: Pubkey,
+    reserve_liquidity_fee_receiver_pubkey: Pubkey,
+    host_fee_receiver_pubkey: Pubkey,
+    reserve_pubkey: Pubkey,
+    lending_market_pubkey: Pubkey,
+    user_transfer_authority_pubkey: Pubkey,
+) -> Instruction {
+    Instruction {
+        program_id,
+        accounts: vec![
+            AccountMeta::new(source_liquidity_pubkey, false),
+            AccountMeta::new(destination_liquidity_pubkey, false),
+            AccountMeta::new(reserve_liquidity_fee_receiver_pubkey, false),
+            AccountMeta::new(host_fee_receiver_pubkey, false),
+            AccountMeta::new(reserve_pubkey, false),
+            AccountMeta::new_readonly(lending_market_pubkey, false),
+            AccountMeta::new_readonly(user_transfer_authority_pubkey, true),
+            AccountMeta::new_readonly(sysvar::instructions::id(), false),
+            AccountMeta::new_readonly(spl_token::id(), false),
+        ],
+        data: LendingInstruction::FlashRepayReserveLiquidity { liquidity_amount }.pack(),
+    }
+}