Contracts expose pallet-xcm (#1248)

This PR introduces:
- XCM  host functions `xcm_send`, `xcm_execute`
- An Xcm trait into the config. that proxy these functions to to
`pallet_xcm`, or disable their usage by using `()`.
- A mock_network and xcm_test files to test the newly added xcm-related
functions.

---------

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>
Co-authored-by: command-bot <>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>

Cargo.lock

@@ -9699,11 +9699,13 @@ dependencies = [
  "frame-system",
  "impl-trait-for-tuples",
  "log",
+ "pallet-assets",
  "pallet-balances",
  "pallet-contracts-fixtures",
  "pallet-contracts-primitives",
  "pallet-contracts-proc-macro",
  "pallet-insecure-randomness-collective-flip",
+ "pallet-message-queue",
  "pallet-proxy",
  "pallet-timestamp",
  "pallet-utility",
@@ -9720,6 +9722,9 @@ dependencies = [
  "sp-keystore",
  "sp-runtime",
  "sp-std 8.0.0",
+ "sp-tracing 10.0.0",
+ "staging-xcm",
+ "staging-xcm-builder",
  "wasm-instrument 0.4.0",
  "wasmi",
  "wat",
@@ -9734,6 +9739,44 @@ dependencies = [
  "wat",
 ]
 
+[[package]]
+name = "pallet-contracts-mock-network"
+version = "1.0.0"
+dependencies = [
+ "assert_matches",
+ "frame-support",
+ "frame-system",
+ "pallet-assets",
+ "pallet-balances",
+ "pallet-contracts",
+ "pallet-contracts-fixtures",
+ "pallet-contracts-primitives",
+ "pallet-contracts-proc-macro",
+ "pallet-insecure-randomness-collective-flip",
+ "pallet-message-queue",
+ "pallet-proxy",
+ "pallet-timestamp",
+ "pallet-utility",
+ "pallet-xcm",
+ "parity-scale-codec",
+ "polkadot-parachain-primitives",
+ "polkadot-primitives",
+ "polkadot-runtime-parachains",
+ "pretty_assertions",
+ "scale-info",
+ "sp-api",
+ "sp-core",
+ "sp-io",
+ "sp-keystore",
+ "sp-runtime",
+ "sp-std 8.0.0",
+ "sp-tracing 10.0.0",
+ "staging-xcm",
+ "staging-xcm-builder",
+ "staging-xcm-executor",
+ "xcm-simulator",
+]
+
 [[package]]
 name = "pallet-contracts-primitives"
 version = "24.0.0"

Cargo.toml

@@ -293,6 +293,7 @@ members = [
 	"substrate/frame/contracts/fixtures",
 	"substrate/frame/contracts/primitives",
 	"substrate/frame/contracts/proc-macro",
+	"substrate/frame/contracts/mock-network",
 	"substrate/frame/conviction-voting",
 	"substrate/frame/core-fellowship",
 	"substrate/frame/democracy",

cumulus/parachains/runtimes/contracts/contracts-rococo/src/contracts.rs

@@ -72,4 +72,5 @@ impl Config for Runtime {
 	type RuntimeHoldReason = RuntimeHoldReason;
 	type Debug = ();
 	type Environment = ();
+	type Xcm = pallet_xcm::Pallet<Self>;
 }

polkadot/xcm/xcm-builder/src/controller.rs

@@ -21,7 +21,7 @@
 use frame_support::pallet_prelude::DispatchError;
 use sp_std::boxed::Box;
 use xcm::prelude::*;
-use xcm_executor::traits::QueryHandler;
+pub use xcm_executor::traits::QueryHandler;
 
 /// Umbrella trait for all Controller traits.
 pub trait Controller<Origin, RuntimeCall, Timeout>:

polkadot/xcm/xcm-builder/src/lib.rs

@@ -119,5 +119,5 @@ pub use pay::{FixedLocation, LocatableAssetId, PayAccountId32OnChainOverXcm, Pay
 mod controller;
 pub use controller::{
 	Controller, ExecuteController, ExecuteControllerWeightInfo, QueryController,
-	QueryControllerWeightInfo, SendController, SendControllerWeightInfo,
+	QueryControllerWeightInfo, QueryHandler, SendController, SendControllerWeightInfo,
 };

substrate/bin/node/runtime/src/lib.rs

@@ -1353,6 +1353,7 @@ impl pallet_contracts::Config for Runtime {
 	type CodeHashLockupDepositPercent = CodeHashLockupDepositPercent;
 	type Debug = ();
 	type Environment = ();
+	type Xcm = ();
 }
 
 impl pallet_sudo::Config for Runtime {

substrate/frame/contracts/Cargo.toml

@@ -48,6 +48,9 @@ sp-io = { path = "../../primitives/io", default-features = false}
 sp-runtime = { path = "../../primitives/runtime", default-features = false}
 sp-std = { path = "../../primitives/std", default-features = false}
 
+xcm = { package = "staging-xcm", path = "../../../polkadot/xcm", default-features = false}
+xcm-builder = { package = "staging-xcm-builder", path = "../../../polkadot/xcm/xcm-builder", default-features = false}
+
 [dev-dependencies]
 array-bytes = "6.1"
 assert_matches = "1"
@@ -56,13 +59,19 @@ pretty_assertions = "1"
 wat = "1"
 pallet-contracts-fixtures = { path = "./fixtures" }
 
+# Polkadot Dependencies
+xcm-builder = {package = "staging-xcm-builder", path = "../../../polkadot/xcm/xcm-builder"}
+
 # Substrate Dependencies
 pallet-balances = { path = "../balances" }
 pallet-timestamp = { path = "../timestamp" }
+pallet-message-queue = { path = "../message-queue" }
 pallet-insecure-randomness-collective-flip = { path = "../insecure-randomness-collective-flip" }
 pallet-utility = { path = "../utility" }
+pallet-assets = { path = "../assets" }
 pallet-proxy = { path = "../proxy" }
 sp-keystore = { path = "../../primitives/keystore" }
+sp-tracing = { path = "../../primitives/tracing" }
 
 [features]
 default = [ "std" ]
@@ -92,12 +101,16 @@ std = [
 	"sp-std/std",
 	"wasm-instrument/std",
 	"wasmi/std",
+	"xcm-builder/std",
+	"xcm/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking/runtime-benchmarks",
 	"frame-support/runtime-benchmarks",
 	"frame-system/runtime-benchmarks",
+	"pallet-assets/runtime-benchmarks",
 	"pallet-balances/runtime-benchmarks",
+	"pallet-message-queue/runtime-benchmarks",
 	"pallet-proxy/runtime-benchmarks",
 	"pallet-timestamp/runtime-benchmarks",
 	"pallet-utility/runtime-benchmarks",
@@ -105,12 +118,15 @@ runtime-benchmarks = [
 	"rand_pcg",
 	"sp-runtime/runtime-benchmarks",
 	"wasm-instrument",
+	"xcm-builder/runtime-benchmarks",
 ]
 try-runtime = [
 	"frame-support/try-runtime",
 	"frame-system/try-runtime",
+	"pallet-assets/try-runtime",
 	"pallet-balances/try-runtime",
 	"pallet-insecure-randomness-collective-flip/try-runtime",
+	"pallet-message-queue/try-runtime",
 	"pallet-proxy/try-runtime",
 	"pallet-timestamp/try-runtime",
 	"pallet-utility/try-runtime",

substrate/frame/contracts/fixtures/data/xcm_execute.wat

@@ -0,0 +1,52 @@
+;; This passes its input to `seal_xcm_execute` and returns the return value to its caller.
+(module
+	(import "seal0" "xcm_execute" (func $xcm_execute (param i32 i32 i32) (result i32)))
+	(import "seal0" "seal_input" (func $seal_input (param i32 i32)))
+	(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	;; 0x1000 = 4k in little endian
+	;; Size of input buffer
+	(data (i32.const 0) "\00\10")
+
+	(func $assert (param i32)
+		(block $ok
+			(br_if $ok
+				(get_local 0)
+			)
+			(unreachable)
+		)
+	)
+
+	(func (export "call")
+		;; Receive the encoded call
+		(call $seal_input
+			(i32.const 4)	;; Pointer to the input buffer
+			(i32.const 0)	;; Pointer to the buffer length (before call) and to the copied data length (after call)
+		)
+		;; Input data layout.
+		;; [0..4) - size of the call
+		;; [4..) - message
+
+		;; Call xcm_execute with provided input.
+		(call $assert
+			(i32.eq
+				(call $xcm_execute
+					(i32.const 4)		     ;; Pointer where the message is stored
+					(i32.load (i32.const 0)) ;; Size of the message
+					(i32.const 100)	         ;; Pointer to the where the outcome is stored
+				)
+				(i32.const 0)
+			)
+		)
+
+		(call $seal_return
+			(i32.const 0)	;; flags
+			(i32.const 100)	;; Pointer to returned value
+			(i32.const 10)	;; length of returned value
+		)
+	)
+
+	(func (export "deploy"))
+)
+

substrate/frame/contracts/fixtures/data/xcm_send.wat

@@ -0,0 +1,59 @@
+;; This passes its input to `seal_xcm_send` and returns the return value to its caller.
+(module
+	(import "seal0" "xcm_send" (func $xcm_send (param i32 i32 i32 i32) (result i32)))
+	(import "seal0" "seal_input" (func $seal_input (param i32 i32)))
+	(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	;; 0x1000 = 4k in little endian
+	;; size of input buffer
+	(data (i32.const 0) "\00\10")
+
+	(func $assert (param i32)
+		(block $ok
+			(br_if $ok
+				(get_local 0)
+			)
+			(unreachable)
+		)
+	)
+
+	(func (export "call")
+
+		;; Receive the encoded call
+		(call $seal_input
+			(i32.const 4)	;; Pointer to the input buffer
+			(i32.const 0)	;; Size of the length buffer
+		)
+
+		;; Input data layout.
+		;; [0..4) - size of the call
+		;; [4..7) - dest
+		;; [7..) - message
+
+		;; Call xcm_send with provided input.
+		(call $assert
+			(i32.eq
+				(call $xcm_send
+					(i32.const 4)               ;; Pointer where the dest is stored
+					(i32.const 7)				;; Pointer where the message is stored
+					(i32.sub
+						(i32.load (i32.const 0)) ;; length of the input buffer
+						(i32.const 3)            ;; Size of the XCM dest
+					)
+					(i32.const 100)	            ;; Pointer to the where the message_id is stored
+				)
+				(i32.const 0)
+			)
+		)
+
+		;; Return the the message_id
+		(call $seal_return
+			(i32.const 0)	;; flags
+			(i32.const 100)	;; Pointer to returned value
+			(i32.const 32)	;; length of returned value
+		)
+	)
+
+	(func (export "deploy"))
+)

substrate/frame/contracts/fixtures/src/lib.rs

@@ -23,6 +23,8 @@ fn fixtures_root_dir() -> PathBuf {
 		// When `CARGO_MANIFEST_DIR` is not set, Rust resolves relative paths from the root folder
 		(Err(_), _) => "substrate/frame/contracts/fixtures/data".into(),
 		(Ok(path), Ok(s)) if s == "pallet-contracts" => PathBuf::from(path).join("fixtures/data"),
+		(Ok(path), Ok(s)) if s == "pallet-contracts-mock-network" =>
+			PathBuf::from(path).parent().unwrap().join("fixtures/data"),
 		(Ok(_), pkg_name) => panic!("Failed to resolve fixture dir for tests from {pkg_name:?}."),
 	}
 }

substrate/frame/contracts/mock-network/Cargo.toml

@@ -0,0 +1,91 @@
+[package]
+name = "pallet-contracts-mock-network"
+version = "1.0.0"
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+homepage = "https://substrate.io"
+repository.workspace = true
+description = "A mock network for testing pallet-contracts"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.6.1", default-features = false, features = [ "derive", "max-encoded-len"] }
+
+frame-support = { path = "../../support", default-features = false}
+frame-system = { path = "../../system", default-features = false}
+pallet-assets = { path = "../../assets" }
+pallet-balances = { path = "../../balances" }
+pallet-contracts = { path = ".." }
+pallet-contracts-primitives = { path = "../primitives", default-features = false}
+pallet-contracts-proc-macro = { path = "../proc-macro" }
+pallet-insecure-randomness-collective-flip = { path = "../../insecure-randomness-collective-flip" }
+pallet-message-queue = { path = "../../message-queue" }
+pallet-proxy = { path = "../../proxy" }
+pallet-timestamp = { path = "../../timestamp" }
+pallet-utility = { path = "../../utility" }
+pallet-xcm = { path = "../../../../polkadot/xcm/pallet-xcm", default-features = false}
+polkadot-parachain-primitives = { path = "../../../../polkadot/parachain"  }
+polkadot-primitives = { path = "../../../../polkadot/primitives"  }
+polkadot-runtime-parachains = {path = "../../../../polkadot/runtime/parachains"}
+scale-info = { version = "2.10.0", default-features = false, features = ["derive"] }
+sp-api = { path = "../../../primitives/api", default-features = false}
+sp-core = { path = "../../../primitives/core", default-features = false}
+sp-io = { path = "../../../primitives/io", default-features = false}
+sp-keystore = { path = "../../../primitives/keystore" }
+sp-runtime = { path = "../../../primitives/runtime", default-features = false}
+sp-std = { path = "../../../primitives/std", default-features = false}
+sp-tracing = { path = "../../../primitives/tracing" }
+xcm = { package = "staging-xcm", path = "../../../../polkadot/xcm", default-features = false}
+xcm-builder = {package = "staging-xcm-builder", path = "../../../../polkadot/xcm/xcm-builder"}
+xcm-executor = { package = "staging-xcm-executor", path = "../../../../polkadot/xcm/xcm-executor", default-features = false}
+xcm-simulator = {path = "../../../../polkadot/xcm/xcm-simulator"}
+
+[dev-dependencies]
+assert_matches = "1"
+pretty_assertions = "1"
+pallet-contracts-fixtures = { path = "../fixtures" }
+
+[features]
+default = [ "std" ]
+std = [
+	"codec/std",
+	"frame-support/std",
+	"frame-system/std",
+	"pallet-balances/std",
+	"pallet-contracts-primitives/std",
+	"pallet-contracts-proc-macro/full",
+	"pallet-contracts/std",
+	"pallet-insecure-randomness-collective-flip/std",
+	"pallet-proxy/std",
+	"pallet-timestamp/std",
+	"pallet-utility/std",
+	"pallet-xcm/std",
+	"scale-info/std",
+	"sp-api/std",
+	"sp-core/std",
+	"sp-io/std",
+	"sp-keystore/std",
+	"sp-runtime/std",
+	"sp-std/std",
+	"xcm-executor/std",
+	"xcm/std",
+]
+
+runtime-benchmarks = [
+	"frame-support/runtime-benchmarks",
+	"frame-system/runtime-benchmarks",
+	"pallet-assets/runtime-benchmarks",
+	"pallet-balances/runtime-benchmarks",
+	"pallet-contracts/runtime-benchmarks",
+	"pallet-message-queue/runtime-benchmarks",
+	"pallet-proxy/runtime-benchmarks",
+	"pallet-timestamp/runtime-benchmarks",
+	"pallet-utility/runtime-benchmarks",
+	"pallet-xcm/runtime-benchmarks",
+	"polkadot-parachain-primitives/runtime-benchmarks",
+	"polkadot-primitives/runtime-benchmarks",
+	"polkadot-runtime-parachains/runtime-benchmarks",
+	"sp-runtime/runtime-benchmarks",
+	"xcm-builder/runtime-benchmarks",
+	"xcm-executor/runtime-benchmarks",
+]

substrate/frame/contracts/mock-network/src/lib.rs

@@ -0,0 +1,151 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+pub mod mocks;
+pub mod parachain;
+pub mod primitives;
+pub mod relay_chain;
+
+#[cfg(test)]
+mod tests;
+
+use crate::primitives::{AccountId, UNITS};
+use sp_runtime::BuildStorage;
+use xcm::latest::{prelude::*, MultiLocation};
+use xcm_executor::traits::ConvertLocation;
+use xcm_simulator::{decl_test_network, decl_test_parachain, decl_test_relay_chain, TestExt};
+
+// Accounts
+pub const ADMIN: sp_runtime::AccountId32 = sp_runtime::AccountId32::new([0u8; 32]);
+pub const ALICE: sp_runtime::AccountId32 = sp_runtime::AccountId32::new([1u8; 32]);
+pub const BOB: sp_runtime::AccountId32 = sp_runtime::AccountId32::new([2u8; 32]);
+
+// Balances
+pub const INITIAL_BALANCE: u128 = 1_000_000_000 * UNITS;
+
+decl_test_parachain! {
+	pub struct ParaA {
+		Runtime = parachain::Runtime,
+		XcmpMessageHandler = parachain::MsgQueue,
+		DmpMessageHandler = parachain::MsgQueue,
+		new_ext = para_ext(1),
+	}
+}
+
+decl_test_relay_chain! {
+	pub struct Relay {
+		Runtime = relay_chain::Runtime,
+		RuntimeCall = relay_chain::RuntimeCall,
+		RuntimeEvent = relay_chain::RuntimeEvent,
+		XcmConfig = relay_chain::XcmConfig,
+		MessageQueue = relay_chain::MessageQueue,
+		System = relay_chain::System,
+		new_ext = relay_ext(),
+	}
+}
+
+decl_test_network! {
+	pub struct MockNet {
+		relay_chain = Relay,
+		parachains = vec![
+			(1, ParaA),
+		],
+	}
+}
+
+pub fn relay_sovereign_account_id() -> AccountId {
+	let location: MultiLocation = (Parent,).into();
+	parachain::SovereignAccountOf::convert_location(&location).unwrap()
+}
+
+pub fn parachain_sovereign_account_id(para: u32) -> AccountId {
+	let location: MultiLocation = (Parachain(para),).into();
+	relay_chain::SovereignAccountOf::convert_location(&location).unwrap()
+}
+
+pub fn parachain_account_sovereign_account_id(
+	para: u32,
+	who: sp_runtime::AccountId32,
+) -> AccountId {
+	let location: MultiLocation = (
+		Parachain(para),
+		AccountId32 { network: Some(relay_chain::RelayNetwork::get()), id: who.into() },
+	)
+		.into();
+	relay_chain::SovereignAccountOf::convert_location(&location).unwrap()
+}
+
+pub fn para_ext(para_id: u32) -> sp_io::TestExternalities {
+	use parachain::{MsgQueue, Runtime, System};
+
+	let mut t = frame_system::GenesisConfig::<Runtime>::default().build_storage().unwrap();
+
+	pallet_balances::GenesisConfig::<Runtime> {
+		balances: vec![
+			(ALICE, INITIAL_BALANCE),
+			(relay_sovereign_account_id(), INITIAL_BALANCE),
+			(BOB, INITIAL_BALANCE),
+		],
+	}
+	.assimilate_storage(&mut t)
+	.unwrap();
+
+	pallet_assets::GenesisConfig::<Runtime> {
+		assets: vec![
+			(0u128, ADMIN, false, 1u128), // Create derivative asset for relay's native token
+		],
+		metadata: Default::default(),
+		accounts: vec![
+			(0u128, ALICE, INITIAL_BALANCE),
+			(0u128, relay_sovereign_account_id(), INITIAL_BALANCE),
+		],
+	}
+	.assimilate_storage(&mut t)
+	.unwrap();
+
+	let mut ext = sp_io::TestExternalities::new(t);
+	ext.execute_with(|| {
+		sp_tracing::try_init_simple();
+		System::set_block_number(1);
+		MsgQueue::set_para_id(para_id.into());
+	});
+	ext
+}
+
+pub fn relay_ext() -> sp_io::TestExternalities {
+	use relay_chain::{Runtime, System};
+
+	let mut t = frame_system::GenesisConfig::<Runtime>::default().build_storage().unwrap();
+
+	pallet_balances::GenesisConfig::<Runtime> {
+		balances: vec![
+			(ALICE, INITIAL_BALANCE),
+			(parachain_sovereign_account_id(1), INITIAL_BALANCE),
+			(parachain_account_sovereign_account_id(1, ALICE), INITIAL_BALANCE),
+		],
+	}
+	.assimilate_storage(&mut t)
+	.unwrap();
+
+	let mut ext = sp_io::TestExternalities::new(t);
+	ext.execute_with(|| {
+		System::set_block_number(1);
+	});
+	ext
+}
+
+pub type ParachainPalletXcm = pallet_xcm::Pallet<parachain::Runtime>;
+pub type ParachainBalances = pallet_balances::Pallet<parachain::Runtime>;

substrate/frame/contracts/mock-network/src/mocks.rs

@@ -0,0 +1,18 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+pub mod msg_queue;
+pub mod relay_message_queue;

substrate/frame/contracts/mock-network/src/mocks/msg_queue.rs

@@ -0,0 +1,168 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Parachain runtime mock.
+
+use codec::{Decode, Encode};
+
+use frame_support::weights::Weight;
+use polkadot_parachain_primitives::primitives::{
+	DmpMessageHandler, Id as ParaId, XcmpMessageFormat, XcmpMessageHandler,
+};
+use polkadot_primitives::BlockNumber as RelayBlockNumber;
+use sp_runtime::traits::{Get, Hash};
+
+use sp_std::prelude::*;
+use xcm::{latest::prelude::*, VersionedXcm};
+
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
+		type XcmExecutor: ExecuteXcm<Self::RuntimeCall>;
+	}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::pallet]
+	#[pallet::without_storage_info]
+	pub struct Pallet<T>(_);
+
+	#[pallet::storage]
+	#[pallet::getter(fn parachain_id)]
+	pub(super) type ParachainId<T: Config> = StorageValue<_, ParaId, ValueQuery>;
+
+	#[pallet::storage]
+	#[pallet::getter(fn received_dmp)]
+	/// A queue of received DMP messages
+	pub(super) type ReceivedDmp<T: Config> = StorageValue<_, Vec<Xcm<T::RuntimeCall>>, ValueQuery>;
+
+	impl<T: Config> Get<ParaId> for Pallet<T> {
+		fn get() -> ParaId {
+			Self::parachain_id()
+		}
+	}
+
+	pub type MessageId = [u8; 32];
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		/// Some XCM was executed OK.
+		Success(Option<T::Hash>),
+		/// Some XCM failed.
+		Fail(Option<T::Hash>, XcmError),
+		/// Bad XCM version used.
+		BadVersion(Option<T::Hash>),
+		/// Bad XCM format used.
+		BadFormat(Option<T::Hash>),
+
+		// DMP
+		/// Downward message is invalid XCM.
+		InvalidFormat(MessageId),
+		/// Downward message is unsupported version of XCM.
+		UnsupportedVersion(MessageId),
+		/// Downward message executed with the given outcome.
+		ExecutedDownward(MessageId, Outcome),
+	}
+
+	impl<T: Config> Pallet<T> {
+		pub fn set_para_id(para_id: ParaId) {
+			ParachainId::<T>::put(para_id);
+		}
+
+		fn handle_xcmp_message(
+			sender: ParaId,
+			_sent_at: RelayBlockNumber,
+			xcm: VersionedXcm<T::RuntimeCall>,
+			max_weight: Weight,
+		) -> Result<Weight, XcmError> {
+			let hash = Encode::using_encoded(&xcm, T::Hashing::hash);
+			let message_hash = Encode::using_encoded(&xcm, sp_io::hashing::blake2_256);
+			let (result, event) = match Xcm::<T::RuntimeCall>::try_from(xcm) {
+				Ok(xcm) => {
+					let location = (Parent, Parachain(sender.into()));
+					match T::XcmExecutor::execute_xcm(location, xcm, message_hash, max_weight) {
+						Outcome::Error(e) => (Err(e), Event::Fail(Some(hash), e)),
+						Outcome::Complete(w) => (Ok(w), Event::Success(Some(hash))),
+						// As far as the caller is concerned, this was dispatched without error, so
+						// we just report the weight used.
+						Outcome::Incomplete(w, e) => (Ok(w), Event::Fail(Some(hash), e)),
+					}
+				},
+				Err(()) => (Err(XcmError::UnhandledXcmVersion), Event::BadVersion(Some(hash))),
+			};
+			Self::deposit_event(event);
+			result
+		}
+	}
+
+	impl<T: Config> XcmpMessageHandler for Pallet<T> {
+		fn handle_xcmp_messages<'a, I: Iterator<Item = (ParaId, RelayBlockNumber, &'a [u8])>>(
+			iter: I,
+			max_weight: Weight,
+		) -> Weight {
+			for (sender, sent_at, data) in iter {
+				let mut data_ref = data;
+				let _ = XcmpMessageFormat::decode(&mut data_ref)
+					.expect("Simulator encodes with versioned xcm format; qed");
+
+				let mut remaining_fragments = data_ref;
+				while !remaining_fragments.is_empty() {
+					if let Ok(xcm) =
+						VersionedXcm::<T::RuntimeCall>::decode(&mut remaining_fragments)
+					{
+						let _ = Self::handle_xcmp_message(sender, sent_at, xcm, max_weight);
+					} else {
+						debug_assert!(false, "Invalid incoming XCMP message data");
+					}
+				}
+			}
+			max_weight
+		}
+	}
+
+	impl<T: Config> DmpMessageHandler for Pallet<T> {
+		fn handle_dmp_messages(
+			iter: impl Iterator<Item = (RelayBlockNumber, Vec<u8>)>,
+			limit: Weight,
+		) -> Weight {
+			for (_i, (_sent_at, data)) in iter.enumerate() {
+				let id = sp_io::hashing::blake2_256(&data[..]);
+				let maybe_versioned = VersionedXcm::<T::RuntimeCall>::decode(&mut &data[..]);
+				match maybe_versioned {
+					Err(_) => {
+						Self::deposit_event(Event::InvalidFormat(id));
+					},
+					Ok(versioned) => match Xcm::try_from(versioned) {
+						Err(()) => Self::deposit_event(Event::UnsupportedVersion(id)),
+						Ok(x) => {
+							let outcome = T::XcmExecutor::execute_xcm(Parent, x.clone(), id, limit);
+							<ReceivedDmp<T>>::append(x);
+							Self::deposit_event(Event::ExecutedDownward(id, outcome));
+						},
+					},
+				}
+			}
+			limit
+		}
+	}
+}

substrate/frame/contracts/mock-network/src/mocks/relay_message_queue.rs

@@ -0,0 +1,52 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use frame_support::{parameter_types, weights::Weight};
+use xcm::latest::prelude::*;
+use xcm_simulator::{
+	AggregateMessageOrigin, ProcessMessage, ProcessMessageError, UmpQueueId, WeightMeter,
+};
+
+use crate::relay_chain::{RuntimeCall, XcmConfig};
+
+parameter_types! {
+	/// Amount of weight that can be spent per block to service messages.
+	pub MessageQueueServiceWeight: Weight = Weight::from_parts(1_000_000_000, 1_000_000);
+	pub const MessageQueueHeapSize: u32 = 65_536;
+	pub const MessageQueueMaxStale: u32 = 16;
+}
+
+/// Message processor to handle any messages that were enqueued into the `MessageQueue` pallet.
+pub struct MessageProcessor;
+impl ProcessMessage for MessageProcessor {
+	type Origin = AggregateMessageOrigin;
+
+	fn process_message(
+		message: &[u8],
+		origin: Self::Origin,
+		meter: &mut WeightMeter,
+		id: &mut [u8; 32],
+	) -> Result<bool, ProcessMessageError> {
+		let para = match origin {
+			AggregateMessageOrigin::Ump(UmpQueueId::Para(para)) => para,
+		};
+		xcm_builder::ProcessXcmMessage::<
+			Junction,
+			xcm_executor::XcmExecutor<XcmConfig>,
+			RuntimeCall,
+		>::process_message(message, Junction::Parachain(para.into()), meter, id)
+	}
+}

substrate/frame/contracts/mock-network/src/parachain.rs

@@ -0,0 +1,353 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Parachain runtime mock.
+
+mod contracts_config;
+use crate::{
+	mocks::msg_queue::pallet as mock_msg_queue,
+	primitives::{AccountId, AssetIdForAssets, Balance},
+};
+use core::marker::PhantomData;
+use frame_support::{
+	construct_runtime, parameter_types,
+	traits::{AsEnsureOriginWithArg, Contains, ContainsPair, Everything, EverythingBut, Nothing},
+	weights::{
+		constants::{WEIGHT_PROOF_SIZE_PER_MB, WEIGHT_REF_TIME_PER_SECOND},
+		Weight,
+	},
+};
+use frame_system::{EnsureRoot, EnsureSigned};
+use pallet_xcm::XcmPassthrough;
+use sp_core::{ConstU32, ConstU64, H256};
+use sp_runtime::traits::{Get, IdentityLookup, MaybeEquivalence};
+
+use sp_std::prelude::*;
+use xcm::latest::prelude::*;
+use xcm_builder::{
+	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowTopLevelPaidExecutionFrom,
+	ConvertedConcreteId, CurrencyAdapter as XcmCurrencyAdapter, EnsureXcmOrigin,
+	FixedRateOfFungible, FixedWeightBounds, FungiblesAdapter, IsConcrete, NativeAsset, NoChecking,
+	ParentAsSuperuser, ParentIsPreset, SignedAccountId32AsNative, SignedToAccountId32,
+	SovereignSignedViaLocation, WithComputedOrigin,
+};
+use xcm_executor::{traits::JustTry, Config, XcmExecutor};
+
+pub type SovereignAccountOf =
+	(AccountId32Aliases<RelayNetwork, AccountId>, ParentIsPreset<AccountId>);
+
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
+
+impl frame_system::Config for Runtime {
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	type Nonce = u64;
+	type Block = Block;
+	type Hash = H256;
+	type Hashing = ::sp_runtime::traits::BlakeTwo256;
+	type AccountId = AccountId;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type RuntimeEvent = RuntimeEvent;
+	type BlockHashCount = BlockHashCount;
+	type BlockWeights = ();
+	type BlockLength = ();
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<Balance>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type DbWeight = ();
+	type BaseCallFilter = Everything;
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+	type OnSetCode = ();
+	type MaxConsumers = ConstU32<16>;
+}
+
+parameter_types! {
+	pub ExistentialDeposit: Balance = 1;
+	pub const MaxLocks: u32 = 50;
+	pub const MaxReserves: u32 = 50;
+}
+
+impl pallet_balances::Config for Runtime {
+	type AccountStore = System;
+	type Balance = Balance;
+	type DustRemoval = ();
+	type ExistentialDeposit = ExistentialDeposit;
+	type FreezeIdentifier = ();
+	type MaxFreezes = ConstU32<0>;
+	type MaxHolds = ConstU32<1>;
+	type MaxLocks = MaxLocks;
+	type MaxReserves = MaxReserves;
+	type ReserveIdentifier = [u8; 8];
+	type RuntimeEvent = RuntimeEvent;
+	type RuntimeHoldReason = RuntimeHoldReason;
+	type RuntimeFreezeReason = RuntimeFreezeReason;
+	type WeightInfo = ();
+}
+
+parameter_types! {
+	pub const AssetDeposit: u128 = 1_000_000;
+	pub const MetadataDepositBase: u128 = 1_000_000;
+	pub const MetadataDepositPerByte: u128 = 100_000;
+	pub const AssetAccountDeposit: u128 = 1_000_000;
+	pub const ApprovalDeposit: u128 = 1_000_000;
+	pub const AssetsStringLimit: u32 = 50;
+	pub const RemoveItemsLimit: u32 = 50;
+}
+
+impl pallet_assets::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type Balance = Balance;
+	type AssetId = AssetIdForAssets;
+	type Currency = Balances;
+	type CreateOrigin = AsEnsureOriginWithArg<EnsureSigned<AccountId>>;
+	type ForceOrigin = EnsureRoot<AccountId>;
+	type AssetDeposit = AssetDeposit;
+	type MetadataDepositBase = MetadataDepositBase;
+	type MetadataDepositPerByte = MetadataDepositPerByte;
+	type AssetAccountDeposit = AssetAccountDeposit;
+	type ApprovalDeposit = ApprovalDeposit;
+	type StringLimit = AssetsStringLimit;
+	type Freezer = ();
+	type Extra = ();
+	type WeightInfo = ();
+	type RemoveItemsLimit = RemoveItemsLimit;
+	type AssetIdParameter = AssetIdForAssets;
+	type CallbackHandle = ();
+	#[cfg(feature = "runtime-benchmarks")]
+	type BenchmarkHelper = ();
+}
+
+parameter_types! {
+	pub const ReservedXcmpWeight: Weight = Weight::from_parts(WEIGHT_REF_TIME_PER_SECOND.saturating_div(4), 0);
+	pub const ReservedDmpWeight: Weight = Weight::from_parts(WEIGHT_REF_TIME_PER_SECOND.saturating_div(4), 0);
+}
+
+parameter_types! {
+	pub const KsmLocation: MultiLocation = MultiLocation::parent();
+	pub const TokenLocation: MultiLocation = Here.into_location();
+	pub const RelayNetwork: NetworkId = ByGenesis([0; 32]);
+	pub UniversalLocation: InteriorMultiLocation = Parachain(MsgQueue::parachain_id().into()).into();
+}
+
+pub type XcmOriginToCallOrigin = (
+	SovereignSignedViaLocation<SovereignAccountOf, RuntimeOrigin>,
+	ParentAsSuperuser<RuntimeOrigin>,
+	SignedAccountId32AsNative<RelayNetwork, RuntimeOrigin>,
+	XcmPassthrough<RuntimeOrigin>,
+);
+
+parameter_types! {
+	pub const XcmInstructionWeight: Weight = Weight::from_parts(1_000, 1_000);
+	pub TokensPerSecondPerMegabyte: (AssetId, u128, u128) = (Concrete(Parent.into()), 1_000_000_000_000, 1024 * 1024);
+	pub const MaxInstructions: u32 = 100;
+	pub const MaxAssetsIntoHolding: u32 = 64;
+	pub ForeignPrefix: MultiLocation = (Parent,).into();
+	pub CheckingAccount: AccountId = PolkadotXcm::check_account();
+	pub TrustedLockPairs: (MultiLocation, MultiAssetFilter) =
+	(Parent.into(), Wild(AllOf { id: Concrete(Parent.into()), fun: WildFungible }));
+}
+
+pub fn estimate_message_fee(number_of_instructions: u64) -> u128 {
+	let weight = estimate_weight(number_of_instructions);
+
+	estimate_fee_for_weight(weight)
+}
+
+pub fn estimate_weight(number_of_instructions: u64) -> Weight {
+	XcmInstructionWeight::get().saturating_mul(number_of_instructions)
+}
+
+pub fn estimate_fee_for_weight(weight: Weight) -> u128 {
+	let (_, units_per_second, units_per_mb) = TokensPerSecondPerMegabyte::get();
+
+	units_per_second * (weight.ref_time() as u128) / (WEIGHT_REF_TIME_PER_SECOND as u128) +
+		units_per_mb * (weight.proof_size() as u128) / (WEIGHT_PROOF_SIZE_PER_MB as u128)
+}
+
+pub type LocalBalancesTransactor =
+	XcmCurrencyAdapter<Balances, IsConcrete<TokenLocation>, SovereignAccountOf, AccountId, ()>;
+
+pub struct FromMultiLocationToAsset<MultiLocation, AssetId>(PhantomData<(MultiLocation, AssetId)>);
+impl MaybeEquivalence<MultiLocation, AssetIdForAssets>
+	for FromMultiLocationToAsset<MultiLocation, AssetIdForAssets>
+{
+	fn convert(value: &MultiLocation) -> Option<AssetIdForAssets> {
+		match *value {
+			MultiLocation { parents: 1, interior: Here } => Some(0 as AssetIdForAssets),
+			MultiLocation { parents: 1, interior: X1(Parachain(para_id)) } =>
+				Some(para_id as AssetIdForAssets),
+			_ => None,
+		}
+	}
+
+	fn convert_back(_id: &AssetIdForAssets) -> Option<MultiLocation> {
+		None
+	}
+}
+
+pub type ForeignAssetsTransactor = FungiblesAdapter<
+	Assets,
+	ConvertedConcreteId<
+		AssetIdForAssets,
+		Balance,
+		FromMultiLocationToAsset<MultiLocation, AssetIdForAssets>,
+		JustTry,
+	>,
+	SovereignAccountOf,
+	AccountId,
+	NoChecking,
+	CheckingAccount,
+>;
+
+/// Means for transacting assets on this chain
+pub type AssetTransactors = (LocalBalancesTransactor, ForeignAssetsTransactor);
+
+pub struct ParentRelay;
+impl Contains<MultiLocation> for ParentRelay {
+	fn contains(location: &MultiLocation) -> bool {
+		location.contains_parents_only(1)
+	}
+}
+pub struct ThisParachain;
+impl Contains<MultiLocation> for ThisParachain {
+	fn contains(location: &MultiLocation) -> bool {
+		matches!(
+			location,
+			MultiLocation { parents: 0, interior: Junctions::X1(Junction::AccountId32 { .. }) }
+		)
+	}
+}
+
+pub type XcmRouter = crate::ParachainXcmRouter<MsgQueue>;
+
+pub type Barrier = (
+	xcm_builder::AllowUnpaidExecutionFrom<ThisParachain>,
+	WithComputedOrigin<
+		(AllowExplicitUnpaidExecutionFrom<ParentRelay>, AllowTopLevelPaidExecutionFrom<Everything>),
+		UniversalLocation,
+		ConstU32<1>,
+	>,
+);
+
+parameter_types! {
+	pub NftCollectionOne: MultiAssetFilter
+		= Wild(AllOf { fun: WildNonFungible, id: Concrete((Parent, GeneralIndex(1)).into()) });
+	pub NftCollectionOneForRelay: (MultiAssetFilter, MultiLocation)
+		= (NftCollectionOne::get(), Parent.into());
+	pub RelayNativeAsset: MultiAssetFilter = Wild(AllOf { fun: WildFungible, id: Concrete((Parent, Here).into()) });
+	pub RelayNativeAssetForRelay: (MultiAssetFilter, MultiLocation) = (RelayNativeAsset::get(), Parent.into());
+}
+pub type TrustedTeleporters =
+	(xcm_builder::Case<NftCollectionOneForRelay>, xcm_builder::Case<RelayNativeAssetForRelay>);
+pub type TrustedReserves = EverythingBut<xcm_builder::Case<NftCollectionOneForRelay>>;
+
+pub struct XcmConfig;
+impl Config for XcmConfig {
+	type RuntimeCall = RuntimeCall;
+	type XcmSender = XcmRouter;
+	type AssetTransactor = AssetTransactors;
+	type OriginConverter = XcmOriginToCallOrigin;
+	type IsReserve = (NativeAsset, TrustedReserves);
+	type IsTeleporter = TrustedTeleporters;
+	type UniversalLocation = UniversalLocation;
+	type Barrier = Barrier;
+	type Weigher = FixedWeightBounds<XcmInstructionWeight, RuntimeCall, MaxInstructions>;
+	type Trader = FixedRateOfFungible<TokensPerSecondPerMegabyte, ()>;
+	type ResponseHandler = PolkadotXcm;
+	type AssetTrap = PolkadotXcm;
+	type AssetLocker = PolkadotXcm;
+	type AssetExchanger = ();
+	type AssetClaims = PolkadotXcm;
+	type SubscriptionService = PolkadotXcm;
+	type PalletInstancesInfo = AllPalletsWithSystem;
+	type FeeManager = ();
+	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
+	type MessageExporter = ();
+	type UniversalAliases = Nothing;
+	type CallDispatcher = RuntimeCall;
+	type SafeCallFilter = Everything;
+	type Aliasers = Nothing;
+}
+
+impl mock_msg_queue::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type XcmExecutor = XcmExecutor<XcmConfig>;
+}
+
+pub type LocalOriginToLocation = SignedToAccountId32<RuntimeOrigin, AccountId, RelayNetwork>;
+
+pub struct TrustedLockerCase<T>(PhantomData<T>);
+impl<T: Get<(MultiLocation, MultiAssetFilter)>> ContainsPair<MultiLocation, MultiAsset>
+	for TrustedLockerCase<T>
+{
+	fn contains(origin: &MultiLocation, asset: &MultiAsset) -> bool {
+		let (o, a) = T::get();
+		a.matches(asset) && &o == origin
+	}
+}
+
+impl pallet_xcm::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type SendXcmOrigin = EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;
+	type XcmRouter = XcmRouter;
+	type ExecuteXcmOrigin = EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;
+	type XcmExecuteFilter = Everything;
+	type XcmExecutor = XcmExecutor<XcmConfig>;
+	type XcmTeleportFilter = Nothing;
+	type XcmReserveTransferFilter = Everything;
+	type Weigher = FixedWeightBounds<XcmInstructionWeight, RuntimeCall, MaxInstructions>;
+	type UniversalLocation = UniversalLocation;
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	const VERSION_DISCOVERY_QUEUE_SIZE: u32 = 100;
+	type AdvertisedXcmVersion = pallet_xcm::CurrentXcmVersion;
+	type Currency = Balances;
+	type CurrencyMatcher = IsConcrete<TokenLocation>;
+	type TrustedLockers = TrustedLockerCase<TrustedLockPairs>;
+	type SovereignAccountOf = SovereignAccountOf;
+	type MaxLockers = ConstU32<8>;
+	type MaxRemoteLockConsumers = ConstU32<0>;
+	type RemoteLockConsumerIdentifier = ();
+	type WeightInfo = pallet_xcm::TestWeightInfo;
+	type AdminOrigin = EnsureRoot<AccountId>;
+}
+
+type Block = frame_system::mocking::MockBlock<Runtime>;
+
+impl pallet_timestamp::Config for Runtime {
+	type Moment = u64;
+	type OnTimestampSet = ();
+	type MinimumPeriod = ConstU64<1>;
+	type WeightInfo = ();
+}
+
+construct_runtime!(
+	pub enum Runtime
+	{
+		System: frame_system,
+		Balances: pallet_balances,
+		Timestamp: pallet_timestamp,
+		MsgQueue: mock_msg_queue,
+		PolkadotXcm: pallet_xcm,
+		Contracts: pallet_contracts,
+		Assets: pallet_assets,
+	}
+);

substrate/frame/contracts/mock-network/src/parachain/contracts_config.rs

@@ -0,0 +1,98 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+use super::{Balances, Runtime, RuntimeCall, RuntimeEvent};
+use crate::{
+	parachain,
+	parachain::RuntimeHoldReason,
+	primitives::{Balance, CENTS},
+};
+use frame_support::{
+	parameter_types,
+	traits::{ConstBool, ConstU32, Contains, Randomness},
+	weights::Weight,
+};
+use frame_system::pallet_prelude::BlockNumberFor;
+use pallet_xcm::BalanceOf;
+use sp_runtime::{traits::Convert, Perbill};
+
+pub const fn deposit(items: u32, bytes: u32) -> Balance {
+	items as Balance * 1 * CENTS + (bytes as Balance) * 1 * CENTS
+}
+
+parameter_types! {
+	pub const DepositPerItem: Balance = deposit(1, 0);
+	pub const DepositPerByte: Balance = deposit(0, 1);
+	pub const DefaultDepositLimit: Balance = deposit(1024, 1024 * 1024);
+	pub Schedule: pallet_contracts::Schedule<Runtime> = Default::default();
+	pub const CodeHashLockupDepositPercent: Perbill = Perbill::from_percent(0);
+	pub const MaxDelegateDependencies: u32 = 32;
+}
+
+pub struct DummyRandomness<T: pallet_contracts::Config>(sp_std::marker::PhantomData<T>);
+
+impl<T: pallet_contracts::Config> Randomness<T::Hash, BlockNumberFor<T>> for DummyRandomness<T> {
+	fn random(_subject: &[u8]) -> (T::Hash, BlockNumberFor<T>) {
+		(Default::default(), Default::default())
+	}
+}
+
+impl Convert<Weight, BalanceOf<Self>> for Runtime {
+	fn convert(w: Weight) -> BalanceOf<Self> {
+		w.ref_time().into()
+	}
+}
+
+#[derive(Clone, Default)]
+pub struct Filters;
+
+impl Contains<RuntimeCall> for Filters {
+	fn contains(call: &RuntimeCall) -> bool {
+		match call {
+			parachain::RuntimeCall::Contracts(_) => true,
+			_ => false,
+		}
+	}
+}
+
+impl pallet_contracts::Config for Runtime {
+	type AddressGenerator = pallet_contracts::DefaultAddressGenerator;
+	type CallFilter = Filters;
+	type CallStack = [pallet_contracts::Frame<Self>; 5];
+	type ChainExtension = ();
+	type CodeHashLockupDepositPercent = CodeHashLockupDepositPercent;
+	type Currency = Balances;
+	type DefaultDepositLimit = DefaultDepositLimit;
+	type DepositPerByte = DepositPerByte;
+	type DepositPerItem = DepositPerItem;
+	type MaxCodeLen = ConstU32<{ 123 * 1024 }>;
+	type MaxDebugBufferLen = ConstU32<{ 2 * 1024 * 1024 }>;
+	type MaxDelegateDependencies = MaxDelegateDependencies;
+	type MaxStorageKeyLen = ConstU32<128>;
+	type Migrations = ();
+	type Randomness = DummyRandomness<Self>;
+	type RuntimeCall = RuntimeCall;
+	type RuntimeEvent = RuntimeEvent;
+	type RuntimeHoldReason = RuntimeHoldReason;
+	type Schedule = Schedule;
+	type Time = super::Timestamp;
+	type UnsafeUnstableInterface = ConstBool<true>;
+	type WeightInfo = ();
+	type WeightPrice = Self;
+	type Debug = ();
+	type Environment = ();
+	type Xcm = pallet_xcm::Pallet<Self>;
+}

substrate/frame/contracts/mock-network/src/primitives.rs

@@ -0,0 +1,23 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+pub type Balance = u128;
+
+pub const UNITS: Balance = 10_000_000_000;
+pub const CENTS: Balance = UNITS / 100; // 100_000_000
+
+pub type AccountId = sp_runtime::AccountId32;
+pub type AssetIdForAssets = u128;

substrate/frame/contracts/mock-network/src/relay_chain.rs

@@ -0,0 +1,236 @@
+// Copyright Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Relay chain runtime mock.
+
+use frame_support::{
+	construct_runtime, parameter_types,
+	traits::{Contains, Everything, Nothing},
+	weights::Weight,
+};
+
+use frame_system::EnsureRoot;
+use sp_core::{ConstU32, H256};
+use sp_runtime::traits::IdentityLookup;
+
+use polkadot_parachain_primitives::primitives::Id as ParaId;
+use polkadot_runtime_parachains::{configuration, origin, shared};
+use xcm::latest::prelude::*;
+use xcm_builder::{
+	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowSubscriptionsFrom,
+	AllowTopLevelPaidExecutionFrom, ChildParachainAsNative, ChildParachainConvertsVia,
+	ChildSystemParachainAsSuperuser, CurrencyAdapter as XcmCurrencyAdapter, DescribeAllTerminal,
+	DescribeFamily, FixedRateOfFungible, FixedWeightBounds, HashedDescription, IsConcrete,
+	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, WithComputedOrigin,
+};
+use xcm_executor::{Config, XcmExecutor};
+
+use super::{
+	mocks::relay_message_queue::*,
+	primitives::{AccountId, Balance},
+};
+
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
+
+impl frame_system::Config for Runtime {
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	type Block = Block;
+	type Nonce = u64;
+	type Hash = H256;
+	type Hashing = ::sp_runtime::traits::BlakeTwo256;
+	type AccountId = AccountId;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type RuntimeEvent = RuntimeEvent;
+	type BlockHashCount = BlockHashCount;
+	type BlockWeights = ();
+	type BlockLength = ();
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<Balance>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type DbWeight = ();
+	type BaseCallFilter = Everything;
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+	type OnSetCode = ();
+	type MaxConsumers = ConstU32<16>;
+}
+
+parameter_types! {
+	pub ExistentialDeposit: Balance = 1;
+	pub const MaxLocks: u32 = 50;
+	pub const MaxReserves: u32 = 50;
+}
+
+impl pallet_balances::Config for Runtime {
+	type MaxLocks = MaxLocks;
+	type Balance = Balance;
+	type RuntimeEvent = RuntimeEvent;
+	type DustRemoval = ();
+	type ExistentialDeposit = ExistentialDeposit;
+	type AccountStore = System;
+	type WeightInfo = ();
+	type MaxReserves = MaxReserves;
+	type ReserveIdentifier = [u8; 8];
+	type FreezeIdentifier = ();
+	type MaxHolds = ConstU32<0>;
+	type MaxFreezes = ConstU32<0>;
+	type RuntimeHoldReason = RuntimeHoldReason;
+	type RuntimeFreezeReason = RuntimeFreezeReason;
+}
+
+impl shared::Config for Runtime {}
+
+impl configuration::Config for Runtime {
+	type WeightInfo = configuration::TestWeightInfo;
+}
+
+parameter_types! {
+	pub RelayNetwork: NetworkId = ByGenesis([0; 32]);
+	pub const TokenLocation: MultiLocation = Here.into_location();
+	pub UniversalLocation: InteriorMultiLocation = Here;
+	pub UnitWeightCost: u64 = 1_000;
+}
+
+pub type SovereignAccountOf = (
+	HashedDescription<AccountId, DescribeFamily<DescribeAllTerminal>>,
+	AccountId32Aliases<RelayNetwork, AccountId>,
+	ChildParachainConvertsVia<ParaId, AccountId>,
+);
+
+pub type LocalBalancesTransactor =
+	XcmCurrencyAdapter<Balances, IsConcrete<TokenLocation>, SovereignAccountOf, AccountId, ()>;
+
+pub type AssetTransactors = LocalBalancesTransactor;
+
+type LocalOriginConverter = (
+	SovereignSignedViaLocation<SovereignAccountOf, RuntimeOrigin>,
+	ChildParachainAsNative<origin::Origin, RuntimeOrigin>,
+	SignedAccountId32AsNative<RelayNetwork, RuntimeOrigin>,
+	ChildSystemParachainAsSuperuser<ParaId, RuntimeOrigin>,
+);
+
+parameter_types! {
+	pub const XcmInstructionWeight: Weight = Weight::from_parts(1_000, 1_000);
+	pub TokensPerSecondPerMegabyte: (AssetId, u128, u128) =
+		(Concrete(TokenLocation::get()), 1_000_000_000_000, 1024 * 1024);
+	pub const MaxInstructions: u32 = 100;
+	pub const MaxAssetsIntoHolding: u32 = 64;
+}
+
+pub struct ChildrenParachains;
+impl Contains<MultiLocation> for ChildrenParachains {
+	fn contains(location: &MultiLocation) -> bool {
+		matches!(location, MultiLocation { parents: 0, interior: X1(Parachain(_)) })
+	}
+}
+
+pub type XcmRouter = crate::RelayChainXcmRouter;
+pub type Barrier = WithComputedOrigin<
+	(
+		AllowExplicitUnpaidExecutionFrom<ChildrenParachains>,
+		AllowTopLevelPaidExecutionFrom<Everything>,
+		AllowSubscriptionsFrom<Everything>,
+	),
+	UniversalLocation,
+	ConstU32<1>,
+>;
+
+pub struct XcmConfig;
+impl Config for XcmConfig {
+	type RuntimeCall = RuntimeCall;
+	type XcmSender = XcmRouter;
+	type AssetTransactor = AssetTransactors;
+	type OriginConverter = LocalOriginConverter;
+	type IsReserve = ();
+	type IsTeleporter = ();
+	type UniversalLocation = UniversalLocation;
+	type Barrier = Barrier;
+	type Weigher = FixedWeightBounds<XcmInstructionWeight, RuntimeCall, MaxInstructions>;
+	type Trader = FixedRateOfFungible<TokensPerSecondPerMegabyte, ()>;
+	type ResponseHandler = XcmPallet;
+	type AssetTrap = XcmPallet;
+	type AssetLocker = XcmPallet;
+	type AssetExchanger = ();
+	type AssetClaims = XcmPallet;
+	type SubscriptionService = XcmPallet;
+	type PalletInstancesInfo = AllPalletsWithSystem;
+	type FeeManager = ();
+	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
+	type MessageExporter = ();
+	type UniversalAliases = Nothing;
+	type CallDispatcher = RuntimeCall;
+	type SafeCallFilter = Everything;
+	type Aliasers = Nothing;
+}
+
+pub type LocalOriginToLocation = SignedToAccountId32<RuntimeOrigin, AccountId, RelayNetwork>;
+
+impl pallet_xcm::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;
+	type XcmRouter = XcmRouter;
+	type ExecuteXcmOrigin = xcm_builder::EnsureXcmOrigin<RuntimeOrigin, LocalOriginToLocation>;
+	type XcmExecuteFilter = Everything;
+	type XcmExecutor = XcmExecutor<XcmConfig>;
+	type XcmTeleportFilter = Everything;
+	type XcmReserveTransferFilter = Everything;
+	type Weigher = FixedWeightBounds<XcmInstructionWeight, RuntimeCall, MaxInstructions>;
+	type UniversalLocation = UniversalLocation;
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	const VERSION_DISCOVERY_QUEUE_SIZE: u32 = 100;
+	type AdvertisedXcmVersion = pallet_xcm::CurrentXcmVersion;
+	type Currency = Balances;
+	type CurrencyMatcher = IsConcrete<TokenLocation>;
+	type TrustedLockers = ();
+	type SovereignAccountOf = SovereignAccountOf;
+	type MaxLockers = ConstU32<8>;
+	type MaxRemoteLockConsumers = ConstU32<0>;
+	type RemoteLockConsumerIdentifier = ();
+	type WeightInfo = pallet_xcm::TestWeightInfo;
+	type AdminOrigin = EnsureRoot<AccountId>;
+}
+
+impl origin::Config for Runtime {}
+
+type Block = frame_system::mocking::MockBlock<Runtime>;
+
+impl pallet_message_queue::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type Size = u32;
+	type HeapSize = MessageQueueHeapSize;
+	type MaxStale = MessageQueueMaxStale;
+	type ServiceWeight = MessageQueueServiceWeight;
+	type MessageProcessor = MessageProcessor;
+	type QueueChangeHandler = ();
+	type WeightInfo = ();
+	type QueuePausedQuery = ();
+}
+
+construct_runtime!(
+	pub enum Runtime {
+		System: frame_system::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		ParasOrigin: origin::{Pallet, Origin},
+		XcmPallet: pallet_xcm::{Pallet, Call, Storage, Event<T>, Origin},
+		MessageQueue: pallet_message_queue::{Pallet, Event<T>},
+	}
+);

substrate/frame/contracts/mock-network/src/tests.rs

@@ -0,0 +1,239 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::{
+	parachain::{self, Runtime},
+	parachain_account_sovereign_account_id,
+	primitives::{AccountId, CENTS},
+	relay_chain, MockNet, ParaA, ParachainBalances, Relay, ALICE, BOB, INITIAL_BALANCE,
+};
+use assert_matches::assert_matches;
+use codec::{Decode, Encode};
+use frame_support::{
+	assert_err,
+	pallet_prelude::Weight,
+	traits::{fungibles::Mutate, Currency},
+};
+use pallet_balances::{BalanceLock, Reasons};
+use pallet_contracts::{CollectEvents, DebugInfo, Determinism};
+use pallet_contracts_fixtures::compile_module;
+use pallet_contracts_primitives::Code;
+use xcm::{v3::prelude::*, VersionedMultiLocation, VersionedXcm};
+use xcm_simulator::TestExt;
+
+type ParachainContracts = pallet_contracts::Pallet<parachain::Runtime>;
+
+/// Instantiate the tests contract, and fund it with some balance and assets.
+fn instantiate_test_contract(name: &str) -> AccountId {
+	let (wasm, _) = compile_module::<Runtime>(name).unwrap();
+
+	// Instantiate contract.
+	let contract_addr = ParaA::execute_with(|| {
+		ParachainContracts::bare_instantiate(
+			ALICE,
+			0,
+			Weight::MAX,
+			None,
+			Code::Upload(wasm),
+			vec![],
+			vec![],
+			DebugInfo::UnsafeDebug,
+			CollectEvents::Skip,
+		)
+		.result
+		.unwrap()
+		.account_id
+	});
+
+	// Funds contract account with some balance and assets.
+	ParaA::execute_with(|| {
+		parachain::Balances::make_free_balance_be(&contract_addr, INITIAL_BALANCE);
+		parachain::Assets::mint_into(0u32.into(), &contract_addr, INITIAL_BALANCE).unwrap();
+	});
+	Relay::execute_with(|| {
+		let sovereign_account = parachain_account_sovereign_account_id(1u32, contract_addr.clone());
+		relay_chain::Balances::make_free_balance_be(&sovereign_account, INITIAL_BALANCE);
+	});
+
+	contract_addr
+}
+
+#[test]
+fn test_xcm_execute() {
+	MockNet::reset();
+
+	let contract_addr = instantiate_test_contract("xcm_execute");
+
+	// Execute XCM instructions through the contract.
+	ParaA::execute_with(|| {
+		let amount: u128 = 10 * CENTS;
+
+		// The XCM used to transfer funds to Bob.
+		let message: xcm_simulator::Xcm<()> = Xcm(vec![
+			WithdrawAsset(vec![(Here, amount).into()].into()),
+			DepositAsset {
+				assets: All.into(),
+				beneficiary: AccountId32 { network: None, id: BOB.clone().into() }.into(),
+			},
+		]);
+
+		let result = ParachainContracts::bare_call(
+			ALICE,
+			contract_addr.clone(),
+			0,
+			Weight::MAX,
+			None,
+			VersionedXcm::V3(message).encode(),
+			DebugInfo::UnsafeDebug,
+			CollectEvents::UnsafeCollect,
+			Determinism::Enforced,
+		)
+		.result
+		.unwrap();
+
+		let mut data = &result.data[..];
+		let outcome = Outcome::decode(&mut data).expect("Failed to decode xcm_execute Outcome");
+		assert_matches!(outcome, Outcome::Complete(_));
+
+		// Check if the funds are subtracted from the account of Alice and added to the account of
+		// Bob.
+		let initial = INITIAL_BALANCE;
+		assert_eq!(parachain::Assets::balance(0, contract_addr), initial);
+		assert_eq!(ParachainBalances::free_balance(BOB), initial + amount);
+	});
+}
+
+#[test]
+fn test_xcm_execute_filtered_call() {
+	MockNet::reset();
+
+	let contract_addr = instantiate_test_contract("xcm_execute");
+
+	ParaA::execute_with(|| {
+		// `remark`  should be rejected, as it is not allowed by our CallFilter.
+		let call = parachain::RuntimeCall::System(frame_system::Call::remark { remark: vec![] });
+		let message: Xcm<parachain::RuntimeCall> = Xcm(vec![Transact {
+			origin_kind: OriginKind::Native,
+			require_weight_at_most: Weight::MAX,
+			call: call.encode().into(),
+		}]);
+
+		let result = ParachainContracts::bare_call(
+			ALICE,
+			contract_addr.clone(),
+			0,
+			Weight::MAX,
+			None,
+			VersionedXcm::V3(message).encode(),
+			DebugInfo::UnsafeDebug,
+			CollectEvents::UnsafeCollect,
+			Determinism::Enforced,
+		);
+
+		assert_err!(result.result, frame_system::Error::<parachain::Runtime>::CallFiltered);
+	});
+}
+
+#[test]
+fn test_xcm_execute_reentrant_call() {
+	MockNet::reset();
+
+	let contract_addr = instantiate_test_contract("xcm_execute");
+
+	ParaA::execute_with(|| {
+		let transact_call = parachain::RuntimeCall::Contracts(pallet_contracts::Call::call {
+			dest: contract_addr.clone(),
+			gas_limit: 1_000_000.into(),
+			storage_deposit_limit: None,
+			data: vec![],
+			value: 0u128,
+		});
+
+		// The XCM used to transfer funds to Bob.
+		let message: Xcm<parachain::RuntimeCall> = Xcm(vec![
+			Transact {
+				origin_kind: OriginKind::Native,
+				require_weight_at_most: 1_000_000_000.into(),
+				call: transact_call.encode().into(),
+			},
+			ExpectTransactStatus(MaybeErrorCode::Success),
+		]);
+
+		let result = ParachainContracts::bare_call(
+			ALICE,
+			contract_addr.clone(),
+			0,
+			Weight::MAX,
+			None,
+			VersionedXcm::V3(message).encode(),
+			DebugInfo::UnsafeDebug,
+			CollectEvents::UnsafeCollect,
+			Determinism::Enforced,
+		)
+		.result
+		.unwrap();
+
+		let mut data = &result.data[..];
+		let outcome = Outcome::decode(&mut data).expect("Failed to decode xcm_execute Outcome");
+		assert_matches!(outcome, Outcome::Incomplete(_, XcmError::ExpectationFalse));
+
+		// Funds should not change hands as the XCM transact failed.
+		assert_eq!(ParachainBalances::free_balance(BOB), INITIAL_BALANCE);
+	});
+}
+
+#[test]
+fn test_xcm_send() {
+	MockNet::reset();
+	let contract_addr = instantiate_test_contract("xcm_send");
+	let fee = parachain::estimate_message_fee(4); // Accounts for the `DescendOrigin` instruction added by `send_xcm`
+
+	// Send XCM instructions through the contract, to lock some funds on the relay chain.
+	ParaA::execute_with(|| {
+		let dest = MultiLocation::from(Parent);
+		let dest = VersionedMultiLocation::V3(dest);
+
+		let message: xcm_simulator::Xcm<()> = Xcm(vec![
+			WithdrawAsset((Here, fee).into()),
+			BuyExecution { fees: (Here, fee).into(), weight_limit: WeightLimit::Unlimited },
+			LockAsset { asset: (Here, 5 * CENTS).into(), unlocker: (Parachain(1)).into() },
+		]);
+		let message = VersionedXcm::V3(message);
+		let exec = ParachainContracts::bare_call(
+			ALICE,
+			contract_addr.clone(),
+			0,
+			Weight::MAX,
+			None,
+			(dest, message).encode(),
+			DebugInfo::UnsafeDebug,
+			CollectEvents::UnsafeCollect,
+			Determinism::Enforced,
+		);
+
+		let mut data = &exec.result.unwrap().data[..];
+		XcmHash::decode(&mut data).expect("Failed to decode xcm_send message_id");
+	});
+
+	Relay::execute_with(|| {
+		// Check if the funds are locked on the relay chain.
+		assert_eq!(
+			relay_chain::Balances::locks(&parachain_account_sovereign_account_id(1, contract_addr)),
+			vec![BalanceLock { id: *b"py/xcmlk", amount: 5 * CENTS, reasons: Reasons::All }]
+		);
+	});
+}

substrate/frame/contracts/src/lib.rs

@@ -403,6 +403,14 @@ pub mod pallet {
 		/// its type appears in the metadata. Only valid value is `()`.
 		#[pallet::constant]
 		type Environment: Get<Environment<Self>>;
+
+		/// A type that exposes XCM APIs, allowing contracts to interact with other parachains, and
+		/// execute XCM programs.
+		type Xcm: xcm_builder::Controller<
+			OriginFor<Self>,
+			<Self as frame_system::Config>::RuntimeCall,
+			BlockNumberFor<Self>,
+		>;
 	}
 
 	#[pallet::hooks]
@@ -1004,6 +1012,8 @@ pub mod pallet {
 		/// in this error. Note that this usually  shouldn't happen as deploying such contracts
 		/// is rejected.
 		NoChainExtension,
+		/// Failed to decode the XCM program.
+		XCMDecodeFailed,
 		/// A contract with the same AccountId already exists.
 		DuplicateContract,
 		/// A contract self destructed in its constructor.

substrate/frame/contracts/src/tests.rs

@@ -486,6 +486,7 @@ impl Config for Test {
 	type MaxDelegateDependencies = MaxDelegateDependencies;
 	type Debug = TestDebug;
 	type Environment = ();
+	type Xcm = ();
 }
 
 pub const ALICE: AccountId32 = AccountId32::new([1u8; 32]);

substrate/frame/contracts/src/wasm/runtime.rs

@@ -23,10 +23,16 @@ use crate::{
 	schedule::HostFnWeights,
 	BalanceOf, CodeHash, Config, DebugBufferVec, Error, SENTINEL,
 };
-
 use bitflags::bitflags;
 use codec::{Decode, DecodeLimit, Encode, MaxEncodedLen};
-use frame_support::{ensure, traits::Get, weights::Weight};
+use frame_support::{
+	dispatch::DispatchInfo,
+	ensure,
+	pallet_prelude::{DispatchResult, DispatchResultWithPostInfo},
+	parameter_types,
+	traits::Get,
+	weights::Weight,
+};
 use pallet_contracts_primitives::{ExecReturnValue, ReturnFlags};
 use pallet_contracts_proc_macro::define_env;
 use sp_io::hashing::{blake2_128, blake2_256, keccak_256, sha2_256};
@@ -36,6 +42,9 @@ use sp_runtime::{
 };
 use sp_std::{fmt, prelude::*};
 use wasmi::{core::HostError, errors::LinkerError, Linker, Memory, Store};
+use xcm::VersionedXcm;
+
+type CallOf<T> = <T as frame_system::Config>::RuntimeCall;
 
 /// The maximum nesting depth a contract can use when encoding types.
 const MAX_DECODE_NESTING: u32 = 256;
@@ -113,6 +122,17 @@ pub enum ReturnCode {
 	EcdsaRecoverFailed = 11,
 	/// sr25519 signature verification failed.
 	Sr25519VerifyFailed = 12,
+	/// The `xcm_execute` call failed.
+	XcmExecutionFailed = 13,
+	/// The `xcm_send` call failed.
+	XcmSendFailed = 14,
+}
+
+parameter_types! {
+	/// Getter types used by [`crate::api_doc::Current::call_runtime`]
+	const CallRuntimeFailed: ReturnCode = ReturnCode::CallRuntimeFailed;
+	/// Getter types used by [`crate::api_doc::Current::xcm_execute`]
+	const XcmExecutionFailed: ReturnCode = ReturnCode::XcmExecutionFailed;
 }
 
 impl From<ExecReturnValue> for ReturnCode {
@@ -461,6 +481,29 @@ fn already_charged(_: u32) -> Option<RuntimeCosts> {
 	None
 }
 
+/// Ensure that the XCM program is executable, by checking that it does not contain any [`Transact`]
+/// instruction with a call that is not allowed by the CallFilter.
+fn ensure_executable<T: Config>(message: &VersionedXcm<CallOf<T>>) -> DispatchResult {
+	use frame_support::traits::Contains;
+	use xcm::prelude::{Transact, Xcm};
+
+	let mut message: Xcm<CallOf<T>> =
+		message.clone().try_into().map_err(|_| Error::<T>::XCMDecodeFailed)?;
+
+	message.iter_mut().try_for_each(|inst| -> DispatchResult {
+		let Transact { ref mut call, .. } = inst else { return Ok(()) };
+		let call = call.ensure_decoded().map_err(|_| Error::<T>::XCMDecodeFailed)?;
+
+		if !<T as Config>::CallFilter::contains(call) {
+			return Err(frame_system::Error::<T>::CallFiltered.into())
+		}
+
+		Ok(())
+	})?;
+
+	Ok(())
+}
+
 /// Can only be used for one call.
 pub struct Runtime<'a, E: Ext + 'a> {
 	ext: &'a mut E,
@@ -558,6 +601,32 @@ impl<'a, E: Ext + 'a> Runtime<'a, E> {
 		self.ext.gas_meter_mut().adjust_gas(charged, token);
 	}
 
+	/// Charge, Run and adjust gas, for executing the given dispatchable.
+	fn call_dispatchable<
+		ErrorReturnCode: Get<ReturnCode>,
+		F: FnOnce(&mut Self) -> DispatchResultWithPostInfo,
+	>(
+		&mut self,
+		dispatch_info: DispatchInfo,
+		run: F,
+	) -> Result<ReturnCode, TrapReason> {
+		use frame_support::dispatch::extract_actual_weight;
+		let charged = self.charge_gas(RuntimeCosts::CallRuntime(dispatch_info.weight))?;
+		let result = run(self);
+		let actual_weight = extract_actual_weight(&result, &dispatch_info);
+		self.adjust_gas(charged, RuntimeCosts::CallRuntime(actual_weight));
+		match result {
+			Ok(_) => Ok(ReturnCode::Success),
+			Err(e) => {
+				if self.ext.append_debug_buffer("") {
+					self.ext.append_debug_buffer("call failed with: ");
+					self.ext.append_debug_buffer(e.into());
+				};
+				Ok(ErrorReturnCode::get())
+			},
+		}
+	}
+
 	/// Read designated chunk from the sandbox memory.
 	///
 	/// Returns `Err` if one of the following conditions occurs:
@@ -633,8 +702,10 @@ impl<'a, E: Ext + 'a> Runtime<'a, E> {
 		let ptr = ptr as usize;
 		let mut bound_checked =
 			memory.get(ptr..ptr + len as usize).ok_or_else(|| Error::<E::T>::OutOfBounds)?;
+
 		let decoded = D::decode_all_with_depth_limit(MAX_DECODE_NESTING, &mut bound_checked)
 			.map_err(|_| DispatchError::from(Error::<E::T>::DecodingFailed))?;
+
 		Ok(decoded)
 	}
 
@@ -1023,6 +1094,7 @@ impl<'a, E: Ext + 'a> Runtime<'a, E> {
 // for every function.
 #[define_env(doc)]
 pub mod env {
+
 	/// Set the value at the given key in the contract storage.
 	///
 	/// Equivalent to the newer [`seal1`][`super::api_doc::Version1::set_storage`] version with the
@@ -2584,7 +2656,7 @@ pub mod env {
 	/// # Return Value
 	///
 	/// Returns `ReturnCode::Success` when the dispatchable was successfully executed and
-	/// returned `Ok`. When the dispatchable was exeuted but returned an error
+	/// returned `Ok`. When the dispatchable was executed but returned an error
 	/// `ReturnCode::CallRuntimeFailed` is returned. The full error is not
 	/// provided because it is not guaranteed to be stable.
 	///
@@ -2605,23 +2677,118 @@ pub mod env {
 		call_ptr: u32,
 		call_len: u32,
 	) -> Result<ReturnCode, TrapReason> {
-		use frame_support::dispatch::{extract_actual_weight, GetDispatchInfo};
+		use frame_support::dispatch::GetDispatchInfo;
 		ctx.charge_gas(RuntimeCosts::CopyFromContract(call_len))?;
 		let call: <E::T as Config>::RuntimeCall =
 			ctx.read_sandbox_memory_as_unbounded(memory, call_ptr, call_len)?;
-		let dispatch_info = call.get_dispatch_info();
-		let charged = ctx.charge_gas(RuntimeCosts::CallRuntime(dispatch_info.weight))?;
-		let result = ctx.ext.call_runtime(call);
-		let actual_weight = extract_actual_weight(&result, &dispatch_info);
-		ctx.adjust_gas(charged, RuntimeCosts::CallRuntime(actual_weight));
-		match result {
-			Ok(_) => Ok(ReturnCode::Success),
+		ctx.call_dispatchable::<CallRuntimeFailed, _>(call.get_dispatch_info(), |ctx| {
+			ctx.ext.call_runtime(call)
+		})
+	}
+
+	/// Execute an XCM program locally, using the contract's address as the origin.
+	/// This is equivalent to dispatching `pallet_xcm::execute` through call_runtime, except that
+	/// the function is called directly instead of being dispatched.
+	///
+	/// # Parameters
+	///
+	/// - `msg_ptr`: the pointer into the linear memory where the [`xcm::prelude::VersionedXcm`] is
+	///   placed.
+	/// - `msg_len`: the length of the message in bytes.
+	/// - `output_ptr`: the pointer into the linear memory where the [`xcm::prelude::Outcome`]
+	///   message id is placed.
+	///
+	/// # Return Value
+	///
+	/// Returns `ReturnCode::Success` when the XCM was successfully executed. When the XCM
+	/// execution fails, `ReturnCode::XcmExecutionFailed` is returned.
+	#[unstable]
+	fn xcm_execute(
+		ctx: _,
+		memory: _,
+		msg_ptr: u32,
+		msg_len: u32,
+		output_ptr: u32,
+	) -> Result<ReturnCode, TrapReason> {
+		use frame_support::dispatch::DispatchInfo;
+		use xcm::VersionedXcm;
+		use xcm_builder::{ExecuteController, ExecuteControllerWeightInfo};
+
+		ctx.charge_gas(RuntimeCosts::CopyFromContract(msg_len))?;
+		let message: VersionedXcm<CallOf<E::T>> =
+			ctx.read_sandbox_memory_as_unbounded(memory, msg_ptr, msg_len)?;
+
+		let execute_weight =
+			<<E::T as Config>::Xcm as ExecuteController<_, _>>::WeightInfo::execute();
+		let weight = ctx.ext.gas_meter().gas_left().max(execute_weight);
+		let dispatch_info = DispatchInfo { weight, ..Default::default() };
+
+		ensure_executable::<E::T>(&message)?;
+		ctx.call_dispatchable::<XcmExecutionFailed, _>(dispatch_info, |ctx| {
+			let origin = crate::RawOrigin::Signed(ctx.ext.address().clone()).into();
+			let outcome = <<E::T as Config>::Xcm>::execute(
+				origin,
+				Box::new(message),
+				weight.saturating_sub(execute_weight),
+			)?;
+
+			ctx.write_sandbox_memory(memory, output_ptr, &outcome.encode())?;
+			let pre_dispatch_weight =
+				<<E::T as Config>::Xcm as ExecuteController<_, _>>::WeightInfo::execute();
+			Ok(Some(outcome.weight_used().saturating_add(pre_dispatch_weight)).into())
+		})
+	}
+
+	/// Send an XCM program from the contract to the specified destination.
+	/// This is equivalent to dispatching `pallet_xcm::send` through `call_runtime`, except that
+	/// the function is called directly instead of being dispatched.
+	///
+	/// # Parameters
+	///
+	/// - `dest_ptr`: the pointer into the linear memory where the
+	///   [`xcm::prelude::VersionedMultiLocation`] is placed.
+	/// - `msg_ptr`: the pointer into the linear memory where the [`xcm::prelude::VersionedXcm`] is
+	///   placed.
+	/// - `msg_len`: the length of the message in bytes.
+	/// - `output_ptr`: the pointer into the linear memory where the [`xcm::v3::XcmHash`] message id
+	///   is placed.
+	///
+	/// # Return Value
+	///
+	/// Returns `ReturnCode::Success` when the message was successfully sent. When the XCM
+	/// execution fails, `ReturnCode::CallRuntimeFailed` is returned.
+	#[unstable]
+	fn xcm_send(
+		ctx: _,
+		memory: _,
+		dest_ptr: u32,
+		msg_ptr: u32,
+		msg_len: u32,
+		output_ptr: u32,
+	) -> Result<ReturnCode, TrapReason> {
+		use xcm::{VersionedMultiLocation, VersionedXcm};
+		use xcm_builder::{SendController, SendControllerWeightInfo};
+
+		ctx.charge_gas(RuntimeCosts::CopyFromContract(msg_len))?;
+		let dest: VersionedMultiLocation = ctx.read_sandbox_memory_as(memory, dest_ptr)?;
+
+		let message: VersionedXcm<()> =
+			ctx.read_sandbox_memory_as_unbounded(memory, msg_ptr, msg_len)?;
+		let weight = <<E::T as Config>::Xcm as SendController<_>>::WeightInfo::send();
+		ctx.charge_gas(RuntimeCosts::CallRuntime(weight))?;
+		let origin = crate::RawOrigin::Signed(ctx.ext.address().clone()).into();
+
+		match <<E::T as Config>::Xcm>::send(origin, dest.into(), message.into()) {
+			Ok(message_id) => {
+				ctx.write_sandbox_memory(memory, output_ptr, &message_id.encode())?;
+				Ok(ReturnCode::Success)
+			},
 			Err(e) => {
 				if ctx.ext.append_debug_buffer("") {
-					ctx.ext.append_debug_buffer("seal0::call_runtime failed with: ");
+					ctx.ext.append_debug_buffer("seal0::xcm_send failed with: ");
 					ctx.ext.append_debug_buffer(e.into());
 				};
-				Ok(ReturnCode::CallRuntimeFailed)
+				Ok(ReturnCode::XcmSendFailed)
 			},
 		}
 	}