From ebfd26b85cbd94113f8e608bcc4ec2de219b2a90 Mon Sep 17 00:00:00 2001
From: Fridrik Asmundsson <fridrik01@gmail.com>
Date: Mon, 15 Jan 2024 19:19:51 +0000
Subject: [PATCH] Add chain metadata actor

---
 Cargo.lock                                   | 536 +++++++++++++++----
 Cargo.toml                                   |  33 +-
 fendermint/actors/Cargo.toml                 |  12 +
 fendermint/actors/build.rs                   | 110 ++++
 fendermint/actors/chainmetadata/Cargo.toml   |  26 +
 fendermint/actors/chainmetadata/src/actor.rs |  89 +++
 fendermint/actors/chainmetadata/src/lib.rs   |   4 +
 fendermint/actors/src/lib.rs                 |   2 +
 ipc/wallet/Cargo.toml                        |   2 +-
 9 files changed, 712 insertions(+), 102 deletions(-)
 create mode 100644 fendermint/actors/Cargo.toml
 create mode 100644 fendermint/actors/build.rs
 create mode 100644 fendermint/actors/chainmetadata/Cargo.toml
 create mode 100644 fendermint/actors/chainmetadata/src/actor.rs
 create mode 100644 fendermint/actors/chainmetadata/src/lib.rs
 create mode 100644 fendermint/actors/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index eae26f2fa..a77404922 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -304,25 +304,96 @@ dependencies = [
  "futures-core",
 ]
 
+[[package]]
+name = "async-channel"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ca33f4bc4ed1babef42cad36cc1f51fa88be00420404e5b1e80ab1b18f7678c"
+dependencies = [
+ "concurrent-queue",
+ "event-listener 4.0.3",
+ "event-listener-strategy",
+ "futures-core",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17ae5ebefcc48e7452b4987947920dac9450be1110cadf34d1b8c116bdbaf97c"
+dependencies = [
+ "async-lock 3.3.0",
+ "async-task",
+ "concurrent-queue",
+ "fastrand 2.0.1",
+ "futures-lite 2.2.0",
+ "slab",
+]
+
+[[package]]
+name = "async-global-executor"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05b1b633a2115cd122d73b955eadd9916c18c8f510ec9cd1686404c60ad1c29c"
+dependencies = [
+ "async-channel 2.1.1",
+ "async-executor",
+ "async-io 2.2.2",
+ "async-lock 3.3.0",
+ "blocking",
+ "futures-lite 2.2.0",
+ "once_cell",
+]
+
+[[package]]
+name = "async-io"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fc5b45d93ef0529756f812ca52e44c221b35341892d3dcc34132ac02f3dd2af"
+dependencies = [
+ "async-lock 2.8.0",
+ "autocfg",
+ "cfg-if",
+ "concurrent-queue",
+ "futures-lite 1.13.0",
+ "log",
+ "parking",
+ "polling 2.8.0",
+ "rustix 0.37.27",
+ "slab",
+ "socket2 0.4.10",
+ "waker-fn",
+]
+
 [[package]]
 name = "async-io"
 version = "2.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6afaa937395a620e33dc6a742c593c01aced20aa376ffb0f628121198578ccc7"
 dependencies = [
- "async-lock",
+ "async-lock 3.3.0",
  "cfg-if",
  "concurrent-queue",
  "futures-io",
- "futures-lite",
+ "futures-lite 2.2.0",
  "parking",
- "polling",
- "rustix",
+ "polling 3.3.1",
+ "rustix 0.38.28",
  "slab",
  "tracing",
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "async-lock"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "287272293e9d8c41773cec55e365490fe034813a2f172f502d6ddcf75b2f582b"
+dependencies = [
+ "event-listener 2.5.3",
+]
+
 [[package]]
 name = "async-lock"
 version = "3.3.0"
@@ -334,6 +405,32 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "async-std"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62565bb4402e926b29953c785397c6dc0391b7b446e45008b0049eb43cec6f5d"
+dependencies = [
+ "async-channel 1.9.0",
+ "async-global-executor",
+ "async-io 1.13.0",
+ "async-lock 2.8.0",
+ "crossbeam-utils",
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-lite 1.13.0",
+ "gloo-timers",
+ "kv-log-macro",
+ "log",
+ "memchr",
+ "once_cell",
+ "pin-project-lite",
+ "pin-utils",
+ "slab",
+ "wasm-bindgen-futures",
+]
+
 [[package]]
 name = "async-stm"
 version = "0.4.0"
@@ -344,6 +441,12 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "async-task"
+version = "4.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbb36e985947064623dbd357f727af08ffd077f93d696782f3c56365fa2e2799"
+
 [[package]]
 name = "async-trait"
 version = "0.1.77"
@@ -408,6 +511,12 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "atomic-waker"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
+
 [[package]]
 name = "attohttpc"
 version = "0.24.1"
@@ -766,6 +875,22 @@ dependencies = [
  "generic-array 0.14.7",
 ]
 
+[[package]]
+name = "blocking"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a37913e8dc4ddcc604f0c6d3bf2887c995153af3611de9e23c352b44c1b9118"
+dependencies = [
+ "async-channel 2.1.1",
+ "async-lock 3.3.0",
+ "async-task",
+ "fastrand 2.0.1",
+ "futures-io",
+ "futures-lite 2.2.0",
+ "piper",
+ "tracing",
+]
+
 [[package]]
 name = "bloom"
 version = "0.3.2"
@@ -1031,20 +1156,6 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
-[[package]]
-name = "cid"
-version = "0.8.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6ed9c8b2d17acb8110c46f1da5bf4a696d745e1474a16db0cd2b49cd0249bf2"
-dependencies = [
- "core2",
- "multibase",
- "multihash 0.16.3",
- "serde",
- "serde_bytes",
- "unsigned-varint 0.7.2",
-]
-
 [[package]]
 name = "cid"
 version = "0.10.1"
@@ -2065,6 +2176,19 @@ dependencies = [
  "syn 2.0.48",
 ]
 
+[[package]]
+name = "env_logger"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
+dependencies = [
+ "atty",
+ "humantime 1.3.0",
+ "log",
+ "regex",
+ "termcolor",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.8.4"
@@ -2081,7 +2205,7 @@ version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95b3f3e67048839cb0d0781f445682a35113da7121f7c949db0e2be96a4fbece"
 dependencies = [
- "humantime",
+ "humantime 2.1.0",
  "is-terminal",
  "log",
  "regex",
@@ -2527,6 +2651,15 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4443176a9f2c162692bd3d352d745ef9413eec5782a80d8fd6f8a1ac692a07f7"
 
+[[package]]
+name = "fastrand"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e51093e27b0797c359783294ca4f0a911c270184cb10f85783b118614a1501be"
+dependencies = [
+ "instant",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.0.1"
@@ -2559,6 +2692,34 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "fendermint_actor_chainmetadata"
+version = "0.1.0"
+dependencies = [
+ "cid",
+ "fil_actors_runtime",
+ "frc42_dispatch",
+ "fvm_ipld_amt",
+ "fvm_ipld_blockstore",
+ "fvm_ipld_encoding",
+ "fvm_sdk",
+ "fvm_shared",
+ "getrandom",
+ "num-derive 0.3.3",
+ "num-traits",
+ "serde",
+ "serde_tuple",
+]
+
+[[package]]
+name = "fendermint_actors"
+version = "0.1.0"
+dependencies = [
+ "fil_actor_bundler",
+ "fil_actors_runtime",
+ "num-traits",
+]
+
 [[package]]
 name = "fendermint_app"
 version = "0.1.0"
@@ -2568,7 +2729,7 @@ dependencies = [
  "async-trait",
  "base64 0.21.6",
  "bytes",
- "cid 0.10.1",
+ "cid",
  "fendermint_abci",
  "fendermint_app_options",
  "fendermint_app_settings",
@@ -2627,7 +2788,7 @@ name = "fendermint_app_options"
 version = "0.1.0"
 dependencies = [
  "bytes",
- "cid 0.10.1",
+ "cid",
  "clap 4.4.14",
  "fendermint_vm_actor_interface",
  "fvm_ipld_encoding",
@@ -2702,7 +2863,7 @@ dependencies = [
  "anyhow",
  "async-trait",
  "axum",
- "cid 0.10.1",
+ "cid",
  "clap 4.4.14",
  "erased-serde",
  "ethers",
@@ -2749,7 +2910,7 @@ name = "fendermint_rocksdb"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "fendermint_storage",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
@@ -2769,7 +2930,7 @@ dependencies = [
  "async-trait",
  "base64 0.21.6",
  "bytes",
- "cid 0.10.1",
+ "cid",
  "clap 4.4.14",
  "ethers",
  "fendermint_crypto",
@@ -2817,7 +2978,7 @@ version = "0.1.0"
 dependencies = [
  "arbitrary",
  "arbtest",
- "cid 0.10.1",
+ "cid",
  "ethers",
  "fendermint_testing",
  "fvm_ipld_encoding",
@@ -2837,7 +2998,7 @@ name = "fendermint_vm_actor_interface"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "ethers",
  "ethers-core",
  "fendermint_crypto",
@@ -2867,7 +3028,7 @@ name = "fendermint_vm_core"
 version = "0.1.0"
 dependencies = [
  "arbitrary",
- "cid 0.10.1",
+ "cid",
  "fnv",
  "fvm_shared",
  "lazy_static",
@@ -2882,7 +3043,7 @@ dependencies = [
 name = "fendermint_vm_encoding"
 version = "0.1.0"
 dependencies = [
- "cid 0.10.1",
+ "cid",
  "fvm_shared",
  "ipc-api",
  "num-traits",
@@ -2896,7 +3057,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "arbitrary",
- "cid 0.10.1",
+ "cid",
  "fendermint_crypto",
  "fendermint_testing",
  "fendermint_vm_core",
@@ -2923,7 +3084,7 @@ dependencies = [
  "anyhow",
  "async-stm",
  "async-trait",
- "cid 0.10.1",
+ "cid",
  "ethers",
  "fendermint_crypto",
  "fendermint_eth_hardhat",
@@ -2970,7 +3131,7 @@ dependencies = [
  "anyhow",
  "arbitrary",
  "blake2b_simd",
- "cid 0.10.1",
+ "cid",
  "ethers",
  "ethers-core",
  "fendermint_crypto",
@@ -2998,7 +3159,7 @@ name = "fendermint_vm_resolver"
 version = "0.1.0"
 dependencies = [
  "async-stm",
- "cid 0.10.1",
+ "cid",
  "im",
  "ipc-api",
  "ipc_ipld_resolver",
@@ -3013,7 +3174,7 @@ dependencies = [
  "anyhow",
  "arbitrary",
  "async-stm",
- "cid 0.10.1",
+ "cid",
  "dircpy",
  "fendermint_testing",
  "fendermint_vm_core",
@@ -3048,7 +3209,7 @@ dependencies = [
  "anyhow",
  "async-stm",
  "async-trait",
- "cid 0.10.1",
+ "cid",
  "clap 4.4.14",
  "ethers",
  "fvm_ipld_encoding",
@@ -3094,6 +3255,25 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "27573eac26f4dd11e2b1916c3fe1baa56407c83c71a773a8ba17ec0bca03b6b7"
 
+[[package]]
+name = "fil_actor_bundler"
+version = "6.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0b1448c65c9a054c640fc086e03b730919ca4feca697c34ed3bda9f16aa982f"
+dependencies = [
+ "anyhow",
+ "async-std",
+ "cid",
+ "clap 4.4.14",
+ "futures",
+ "fvm_ipld_blockstore",
+ "fvm_ipld_car",
+ "fvm_ipld_encoding",
+ "serde",
+ "serde_ipld_dagcbor",
+ "serde_json",
+]
+
 [[package]]
 name = "fil_actors_evm_shared"
 version = "12.0.0"
@@ -3114,23 +3294,29 @@ source = "git+https://github.com/filecoin-project/builtin-actors?tag=v12.0.0#b86
 dependencies = [
  "anyhow",
  "base64 0.21.6",
+ "blake2b_simd",
  "byteorder",
  "castaway",
- "cid 0.10.1",
+ "cid",
  "fvm_ipld_amt",
  "fvm_ipld_bitfield",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
  "fvm_ipld_hamt 0.8.0",
  "fvm_shared",
+ "hex",
  "integer-encoding",
  "itertools 0.10.5",
+ "lazy_static",
+ "libsecp256k1",
  "log",
  "multihash 0.18.1",
  "num",
  "num-derive 0.3.3",
  "num-traits",
  "paste",
+ "pretty_env_logger",
+ "rand",
  "regex",
  "serde",
  "serde_repr",
@@ -3313,6 +3499,44 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "frc42_dispatch"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe63cf3ff3e332ef15fd19d95cffcb3fd2af14ccb3cb04abc730271c1362c4f"
+dependencies = [
+ "frc42_hasher",
+ "frc42_macros",
+ "fvm_ipld_encoding",
+ "fvm_sdk",
+ "fvm_shared",
+ "thiserror",
+]
+
+[[package]]
+name = "frc42_hasher"
+version = "3.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08a35e7214108f81cefc17b0466be01279f384faf913918a12dbc8528bb758a4"
+dependencies = [
+ "fvm_sdk",
+ "fvm_shared",
+ "thiserror",
+]
+
+[[package]]
+name = "frc42_macros"
+version = "3.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f50cd62b077775194bde67eef8076b31f915b9c099f3a7fd1a760363d65f145"
+dependencies = [
+ "blake2b_simd",
+ "frc42_hasher",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "fs2"
 version = "0.4.3"
@@ -3388,13 +3612,31 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
 
+[[package]]
+name = "futures-lite"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49a9d51ce47660b1e808d3c990b4709f2f415d928835a17dfd16991515c46bce"
+dependencies = [
+ "fastrand 1.9.0",
+ "futures-core",
+ "futures-io",
+ "memchr",
+ "parking",
+ "pin-project-lite",
+ "waker-fn",
+]
+
 [[package]]
 name = "futures-lite"
 version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "445ba825b27408685aaecefd65178908c36c6e96aaf6d8599419d46e624192ba"
 dependencies = [
+ "fastrand 2.0.1",
  "futures-core",
+ "futures-io",
+ "parking",
  "pin-project-lite",
 ]
 
@@ -3490,7 +3732,7 @@ dependencies = [
  "arbitrary",
  "blake2b_simd",
  "byteorder",
- "cid 0.10.1",
+ "cid",
  "derive_more",
  "filecoin-proofs-api",
  "fvm-wasm-instrument",
@@ -3539,7 +3781,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5fea333475130094f27ce67809aae3f69eb5247541d835950b7c5da733dbbb34"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
  "itertools 0.11.0",
@@ -3567,7 +3809,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "417f52f6915b9f9a68de8462e1cf46f14a2c16420f484b8d2066873de2ffe420"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "multihash 0.18.1",
 ]
 
@@ -3577,7 +3819,7 @@ version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6190f03442b67b21a3d4e115c4d4dd3468aed24e27ebb074218822c1b3df41ba"
 dependencies = [
- "cid 0.10.1",
+ "cid",
  "futures",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
@@ -3593,11 +3835,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "90608092e31d9a06236268c58f7c36668ab4b2a48afafe3a97e08f094ad7ae50"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "fvm_ipld_blockstore",
  "multihash 0.18.1",
  "serde",
- "serde_ipld_dagcbor 0.4.2",
+ "serde_ipld_dagcbor",
  "serde_repr",
  "serde_tuple",
  "thiserror",
@@ -3611,7 +3853,7 @@ checksum = "03a53e14c789449cec999ca0e93d909490c921b967adb7a9ec8f12286fb809bd"
 dependencies = [
  "anyhow",
  "byteorder",
- "cid 0.10.1",
+ "cid",
  "forest_hash_utils",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
@@ -3631,7 +3873,7 @@ checksum = "48c900736087ff87cc51f669eee2f8e000c80717472242eb3f712aaa059ac3b3"
 dependencies = [
  "anyhow",
  "byteorder",
- "cid 0.10.1",
+ "cid",
  "forest_hash_utils",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
@@ -3643,6 +3885,22 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "fvm_sdk"
+version = "4.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "258cfc9a2e5dcb28ffcadd4abed504893996d31238488a07ef7d2a6a6e80e1ec"
+dependencies = [
+ "byteorder",
+ "cid",
+ "fvm_ipld_encoding",
+ "fvm_shared",
+ "lazy_static",
+ "log",
+ "num-traits",
+ "thiserror",
+]
+
 [[package]]
 name = "fvm_shared"
 version = "4.0.0"
@@ -3654,7 +3912,7 @@ dependencies = [
  "bitflags 2.4.1",
  "blake2b_simd",
  "bls-signatures 0.15.0",
- "cid 0.10.1",
+ "cid",
  "data-encoding",
  "data-encoding-macro",
  "filecoin-proofs-api",
@@ -3961,7 +4219,7 @@ dependencies = [
  "ipnet",
  "once_cell",
  "rand",
- "socket2",
+ "socket2 0.5.5",
  "thiserror",
  "tinyvec",
  "tokio",
@@ -4083,6 +4341,15 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
 
+[[package]]
+name = "humantime"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
+dependencies = [
+ "quick-error",
+]
+
 [[package]]
 name = "humantime"
 version = "2.1.0"
@@ -4106,7 +4373,7 @@ dependencies = [
  "httpdate",
  "itoa",
  "pin-project-lite",
- "socket2",
+ "socket2 0.5.5",
  "tokio",
  "tower-service",
  "tracing",
@@ -4242,7 +4509,7 @@ version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6b0422c86d7ce0e97169cc42e04ae643caf278874a7a3c87b8150a220dc7e1e"
 dependencies = [
- "async-io",
+ "async-io 2.2.2",
  "core-foundation",
  "fnv",
  "futures",
@@ -4385,6 +4652,17 @@ version = "3.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8bb03732005da905c88227371639bf1ad885cc712789c011c31c5fb3ab3ccf02"
 
+[[package]]
+name = "io-lifetimes"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eae7b9aee968036d54dce06cebaefd919e4472e753296daccd6d344e3e2df0c2"
+dependencies = [
+ "hermit-abi 0.3.3",
+ "libc",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "iowrap"
 version = "0.2.1"
@@ -4399,7 +4677,7 @@ name = "ipc-api"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "ethers",
  "fil_actors_runtime",
  "fnv",
@@ -4424,11 +4702,11 @@ name = "ipc-cli"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "async-channel",
+ "async-channel 1.9.0",
  "async-trait",
  "base64 0.21.6",
  "bytes",
- "cid 0.10.1",
+ "cid",
  "clap 4.4.14",
  "clap_complete",
  "env_logger 0.10.1",
@@ -4466,11 +4744,11 @@ name = "ipc-provider"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "async-channel",
+ "async-channel 1.9.0",
  "async-trait",
  "base64 0.21.6",
  "bytes",
- "cid 0.10.1",
+ "cid",
  "dirs",
  "ethers",
  "ethers-contract",
@@ -4507,7 +4785,7 @@ name = "ipc-types"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "fvm_ipld_amt",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
@@ -4546,7 +4824,7 @@ dependencies = [
  "quickcheck_macros",
  "rand",
  "serde",
- "serde_ipld_dagcbor 0.2.2",
+ "serde_ipld_dagcbor",
  "serde_json",
  "tempfile",
  "thiserror",
@@ -4603,7 +4881,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b58db92f96b720de98181bbbe63c831e87005ab460c1bf306eb2622b4707997f"
 dependencies = [
- "socket2",
+ "socket2 0.5.5",
  "widestring",
  "windows-sys 0.48.0",
  "winreg",
@@ -4622,7 +4900,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bad00257d07be169d870ab665980b06cdb366d792ad690bf2e76876dc503455"
 dependencies = [
  "hermit-abi 0.3.3",
- "rustix",
+ "rustix 0.38.28",
  "windows-sys 0.52.0",
 ]
 
@@ -4771,6 +5049,15 @@ dependencies = [
  "cpufeatures",
 ]
 
+[[package]]
+name = "kv-log-macro"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0de8b303297635ad57c9f5059fd9cee7a47f8e8daa09df0fcd07dd39fb22977f"
+dependencies = [
+ "log",
+]
+
 [[package]]
 name = "lalrpop"
 version = "0.20.0"
@@ -4859,7 +5146,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5acd707e8d8b092e967b2af978ed84709eaded82b75effe6cb6f6cc797ef8158"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "core2",
  "multibase",
  "multihash 0.18.1",
@@ -5136,7 +5423,7 @@ dependencies = [
  "libp2p-swarm",
  "rand",
  "smallvec",
- "socket2",
+ "socket2 0.5.5",
  "tokio",
  "tracing",
  "void",
@@ -5258,7 +5545,7 @@ dependencies = [
  "rand",
  "ring 0.16.20",
  "rustls 0.21.10",
- "socket2",
+ "socket2 0.5.5",
  "thiserror",
  "tokio",
  "tracing",
@@ -5331,7 +5618,7 @@ dependencies = [
  "libc",
  "libp2p-core",
  "libp2p-identity",
- "socket2",
+ "socket2 0.5.5",
  "tokio",
  "tracing",
 ]
@@ -5478,6 +5765,12 @@ version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.12"
@@ -5505,6 +5798,9 @@ name = "log"
 version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+dependencies = [
+ "value-bag",
+]
 
 [[package]]
 name = "lru"
@@ -5583,7 +5879,7 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b2cffa4ad52c6f791f4f8b15f0c05f9824b2ced1160e88cc393d64fff9a8ac64"
 dependencies = [
- "rustix",
+ "rustix 0.38.28",
 ]
 
 [[package]]
@@ -5707,19 +6003,6 @@ dependencies = [
  "data-encoding-macro",
 ]
 
-[[package]]
-name = "multihash"
-version = "0.16.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1c346cf9999c631f002d8f977c4eaeaa0e6386f16007202308d0b3757522c2cc"
-dependencies = [
- "core2",
- "multihash-derive",
- "serde",
- "serde-big-array",
- "unsigned-varint 0.7.2",
-]
-
 [[package]]
 name = "multihash"
 version = "0.18.1"
@@ -6590,6 +6873,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "piper"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "668d31b1c4eba19242f2088b2bf3316b82ca31082a8335764db4e083db7485d4"
+dependencies = [
+ "atomic-waker",
+ "fastrand 2.0.1",
+ "futures-io",
+]
+
 [[package]]
 name = "pkcs8"
 version = "0.9.0"
@@ -6622,6 +6916,22 @@ version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "626dec3cac7cc0e1577a2ec3fc496277ec2baa084bebad95bb6fdbfae235f84c"
 
+[[package]]
+name = "polling"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b2d323e8ca7996b3e23126511a523f7e62924d93ecd5ae73b333815b0eb3dce"
+dependencies = [
+ "autocfg",
+ "bitflags 1.3.2",
+ "cfg-if",
+ "concurrent-queue",
+ "libc",
+ "log",
+ "pin-project-lite",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "polling"
 version = "3.3.1"
@@ -6631,7 +6941,7 @@ dependencies = [
  "cfg-if",
  "concurrent-queue",
  "pin-project-lite",
- "rustix",
+ "rustix 0.38.28",
  "tracing",
  "windows-sys 0.52.0",
 ]
@@ -6692,6 +7002,16 @@ dependencies = [
  "yansi",
 ]
 
+[[package]]
+name = "pretty_env_logger"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "926d36b9553851b8b0005f1275891b392ee4d2d833852c417ed025477350fb9d"
+dependencies = [
+ "env_logger 0.7.1",
+ "log",
+]
+
 [[package]]
 name = "prettyplease"
 version = "0.2.16"
@@ -6984,7 +7304,7 @@ checksum = "055b4e778e8feb9f93c4e439f71dc2156ef13360b432b799e179a8c4cdf0b1d7"
 dependencies = [
  "bytes",
  "libc",
- "socket2",
+ "socket2 0.5.5",
  "tracing",
  "windows-sys 0.48.0",
 ]
@@ -7385,6 +7705,20 @@ dependencies = [
  "nom",
 ]
 
+[[package]]
+name = "rustix"
+version = "0.37.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fea8ca367a3a01fe35e6943c400addf443c0f57670e6ec51196f71a4b8762dd2"
+dependencies = [
+ "bitflags 1.3.2",
+ "errno",
+ "io-lifetimes",
+ "libc",
+ "linux-raw-sys 0.3.8",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "rustix"
 version = "0.38.28"
@@ -7394,7 +7728,7 @@ dependencies = [
  "bitflags 2.4.1",
  "errno",
  "libc",
- "linux-raw-sys",
+ "linux-raw-sys 0.4.12",
  "windows-sys 0.52.0",
 ]
 
@@ -7700,18 +8034,6 @@ dependencies = [
  "syn 2.0.48",
 ]
 
-[[package]]
-name = "serde_ipld_dagcbor"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1e23de7a4a18dff77ab9531f279a882500b8cf3549fde044d4e10481b411f1e"
-dependencies = [
- "cbor4ii",
- "cid 0.8.6",
- "scopeguard",
- "serde",
-]
-
 [[package]]
 name = "serde_ipld_dagcbor"
 version = "0.4.2"
@@ -7719,7 +8041,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e880e0b1f9c7a8db874642c1217f7e19b29e325f24ab9f0fcb11818adec7f01"
 dependencies = [
  "cbor4ii",
- "cid 0.10.1",
+ "cid",
  "scopeguard",
  "serde",
 ]
@@ -8017,6 +8339,16 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "socket2"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f7916fc008ca5542385b89a3d3ce689953c143e9304a9bf8beec1de48994c0d"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "socket2"
 version = "0.5.5"
@@ -8432,9 +8764,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "01ce4141aa927a6d1bd34a041795abd0db1cccba5d5f24b009f694bdf3a1f3fa"
 dependencies = [
  "cfg-if",
- "fastrand",
+ "fastrand 2.0.1",
  "redox_syscall",
- "rustix",
+ "rustix 0.38.28",
  "windows-sys 0.52.0",
 ]
 
@@ -8732,7 +9064,7 @@ dependencies = [
  "parking_lot",
  "pin-project-lite",
  "signal-hook-registry",
- "socket2",
+ "socket2 0.5.5",
  "tokio-macros",
  "windows-sys 0.48.0",
 ]
@@ -9342,6 +9674,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
 
+[[package]]
+name = "value-bag"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cdbaf5e132e593e9fc1de6a15bbec912395b11fb9719e061cf64f804524c503"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
@@ -9366,7 +9704,7 @@ version = "1.0.0"
 source = "git+https://github.com/filecoin-project/builtin-actors?tag=v12.0.0#b86938e410daebf27f9397fd622370a16b24f58b"
 dependencies = [
  "anyhow",
- "cid 0.10.1",
+ "cid",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding",
  "fvm_ipld_hamt 0.8.0",
@@ -9384,6 +9722,12 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 
+[[package]]
+name = "waker-fn"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3c4517f54858c779bbcbf228f4fca63d121bf85fbecb2dc578cdf4a39395690"
+
 [[package]]
 name = "walkdir"
 version = "2.4.0"
@@ -9654,7 +9998,7 @@ dependencies = [
  "log",
  "object 0.31.1",
  "rustc-demangle",
- "rustix",
+ "rustix 0.38.28",
  "serde",
  "target-lexicon",
  "wasmtime-environ",
@@ -9701,7 +10045,7 @@ dependencies = [
  "memoffset",
  "paste",
  "rand",
- "rustix",
+ "rustix 0.38.28",
  "sptr",
  "wasm-encoder 0.31.1",
  "wasmtime-asm-macros",
diff --git a/Cargo.toml b/Cargo.toml
index f33a1a7bb..15a0c408d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -26,6 +26,8 @@ members = [
   "fendermint/testing",
   "fendermint/testing/*-test",
   "fendermint/vm/*",
+  "fendermint/actors",
+  "fendermint/actors/chainmetadata",
 ]
 
 [workspace.package]
@@ -65,10 +67,14 @@ gcra = "0.4"
 hex = "0.4"
 im = "15.1.0"
 integer-encoding = { version = "3.0.3", default-features = false }
-jsonrpc-v2 = { version = "0.11", default-features = false, features = ["bytes-v10"] }
+jsonrpc-v2 = { version = "0.11", default-features = false, features = [
+  "bytes-v10",
+] }
 k256 = "0.11" # Same as tendermint-rs
 lazy_static = "1.4"
-libipld = { version = "0.16", default-features = false, features = ["dag-cbor"] }
+libipld = { version = "0.16", default-features = false, features = [
+  "dag-cbor",
+] }
 libp2p = { version = "0.53", default-features = false, features = [
   "gossipsub",
   "kad",
@@ -151,7 +157,7 @@ openssl = { version = "0.10", features = ["vendored"] }
 # to version which are different than the ones in the builtin-actors project, and since
 # they are 0.x cargo cannot upgrade them automatically, which leads to version conflicts.
 fvm = { version = "4.0.0", default-features = false }     # no opencl feature or it fails on CI
-fvm_shared = { version = "4.0.0", features = ["crypto"] }
+fvm_shared = { version = "4.0.0" }
 fvm_sdk = { version = "4.0.0" }
 
 fvm_ipld_blockstore = "0.2.0"
@@ -178,7 +184,10 @@ fil_actors_runtime = { git = "https://github.com/filecoin-project/builtin-actors
 # Using 0.8 because of ref-fvm.
 # 0.9 would be better because of its updated quickcheck dependency.
 # 0.10 breaks some API.
-cid = { version = "0.10.1", default-features = false, features = ["serde-codec", "std"] }
+cid = { version = "0.10.1", default-features = false, features = [
+  "serde-codec",
+  "std",
+] }
 
 # Depending on the release cycle, this dependency might want an earlier version of the FVM.
 # We can work around it by hardcoding the method hashes; currently there is only one.
@@ -188,7 +197,11 @@ cid = { version = "0.10.1", default-features = false, features = ["serde-codec",
 tower-abci = { version = "0.7" }
 tendermint = { version = "0.31", features = ["secp256k1"] }
 tendermint-config = "0.33.0"
-tendermint-rpc = { version = "0.31", features = ["secp256k1", "http-client", "websocket-client"] }
+tendermint-rpc = { version = "0.31", features = [
+  "secp256k1",
+  "http-client",
+  "websocket-client",
+] }
 tendermint-proto = { version = "0.31" }
 
 [patch.crates-io]
@@ -196,3 +209,13 @@ tendermint-proto = { version = "0.31" }
 gcra = { git = "https://github.com/consensus-shipyard/gcra-rs.git", branch = "main" }
 # Contains some API changes that the upstream has not merged.
 merkle-tree-rs = { git = "https://github.com/consensus-shipyard/merkle-tree-rs.git", branch = "dev" }
+
+[profile.wasm]
+inherits = "release"
+panic = "abort"
+overflow-checks = false
+lto = true
+opt-level = "z"
+strip = true
+codegen-units = 1
+incremental = false
diff --git a/fendermint/actors/Cargo.toml b/fendermint/actors/Cargo.toml
new file mode 100644
index 000000000..b8f235be6
--- /dev/null
+++ b/fendermint/actors/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "fendermint_actors"
+version = "0.1.0"
+
+[build-dependencies]
+fil_actors_runtime = { workspace = true, features = ["test_utils"] }
+fil_actor_bundler = "6.1.0"
+num-traits = { workspace = true}
+
+[features]
+default=[]
+testing=[]
\ No newline at end of file
diff --git a/fendermint/actors/build.rs b/fendermint/actors/build.rs
new file mode 100644
index 000000000..be5e279f8
--- /dev/null
+++ b/fendermint/actors/build.rs
@@ -0,0 +1,110 @@
+// Copyright 2022-2024 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+extern crate fil_actor_bundler;
+extern crate fil_actors_runtime;
+extern crate num_traits;
+
+use fil_actor_bundler::Bundler;
+use std::error::Error;
+use std::io::{BufRead, BufReader};
+use std::path::Path;
+use std::process::{Command, Stdio};
+use std::thread;
+
+const ACTORS: &[&str] = &["chainmetadata"];
+
+const FILES_TO_WATCH: &[&str] = &["Cargo.toml", "src", "actors"];
+
+fn main() -> Result<(), Box<dyn Error>> {
+    // Cargo executable location.
+    let cargo = std::env::var_os("CARGO").expect("no CARGO env var");
+
+    let out_dir = std::env::var_os("OUT_DIR")
+        .as_ref()
+        .map(Path::new)
+        .map(|p| p.join("bundle"))
+        .expect("no OUT_DIR env var");
+    println!("cargo:warning=out_dir: {:?}", &out_dir);
+
+    let manifest_path =
+        Path::new(&std::env::var_os("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR unset"))
+            .join("Cargo.toml");
+
+    for file in FILES_TO_WATCH.to_vec() {
+        println!("cargo:rerun-if-changed={}", file);
+    }
+
+    // Cargo build command for all test_actors at once.
+    let mut cmd = Command::new(cargo);
+    cmd.arg("build")
+        .args(
+            ACTORS
+                .iter()
+                .map(|pkg| "-p=fendermint_actor_".to_owned() + pkg),
+        )
+        .arg("--target=wasm32-unknown-unknown")
+        .arg("--profile=wasm")
+        .arg("--manifest-path=".to_owned() + manifest_path.to_str().unwrap())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        // We are supposed to only generate artifacts under OUT_DIR,
+        // so set OUT_DIR as the target directory for this build.
+        .env("CARGO_TARGET_DIR", &out_dir)
+        // As we are being called inside a build-script, this env variable is set. However, we set
+        // our own `RUSTFLAGS` and thus, we need to remove this. Otherwise cargo favors this
+        // env variable.
+        .env_remove("CARGO_ENCODED_RUSTFLAGS");
+
+    // Print out the command line we're about to run.
+    println!("cargo:warning=cmd={:?}", &cmd);
+
+    // Launch the command.
+    let mut child = cmd.spawn().expect("failed to launch cargo build");
+
+    // Pipe the output as cargo warnings. Unfortunately this is the only way to
+    // get cargo build to print the output.
+    let stdout = child.stdout.take().expect("no stdout");
+    let stderr = child.stderr.take().expect("no stderr");
+    let j1 = thread::spawn(move || {
+        for line in BufReader::new(stderr).lines() {
+            println!("cargo:warning={:?}", line.unwrap());
+        }
+    });
+    let j2 = thread::spawn(move || {
+        for line in BufReader::new(stdout).lines() {
+            println!("cargo:warning={:?}", line.unwrap());
+        }
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+
+    let result = child.wait().expect("failed to wait for build to finish");
+    if !result.success() {
+        return Err("actor build failed".into());
+    }
+
+    let dst = Path::new(&out_dir).join("bundle.car");
+    let mut bundler = Bundler::new(&dst);
+    for (&pkg, id) in ACTORS.iter().zip(1u32..) {
+        let bytecode_path = Path::new(&out_dir)
+            .join("wasm32-unknown-unknown/wasm")
+            .join(format!("fendermint_actor_{}.wasm", pkg));
+
+        // This actor version doesn't force synthetic CIDs; it uses genuine
+        // content-addressed CIDs.
+        let forced_cid = None;
+
+        let cid = bundler
+            .add_from_file(id, pkg.to_owned(), forced_cid, &bytecode_path)
+            .unwrap_or_else(|err| {
+                panic!("failed to add file {:?} to bundle for actor {}: {}", bytecode_path, id, err)
+            });
+        println!("cargo:warning=added {} ({}) to bundle with CID {}", pkg, id, cid);
+    }
+    bundler.finish().expect("failed to finish bundle");
+
+    println!("cargo:warning=bundle={}", dst.display());
+
+    Ok(())
+}
diff --git a/fendermint/actors/chainmetadata/Cargo.toml b/fendermint/actors/chainmetadata/Cargo.toml
new file mode 100644
index 000000000..6bc24c845
--- /dev/null
+++ b/fendermint/actors/chainmetadata/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+name = "fendermint_actor_chainmetadata"
+description = "Actor for storing chain metadata"
+license.workspace = true
+edition.workspace = true
+authors.workspace = true
+version = "0.1.0"
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+cid = { workspace = true, default-features = false }
+frc42_dispatch = "5.0.0"
+fvm_sdk = { workspace = true }
+fvm_ipld_blockstore = { workspace = true }
+fil_actors_runtime = { workspace = true }
+fvm_shared = { workspace = true }
+fvm_ipld_encoding = { workspace = true }
+fvm_ipld_amt = { workspace = true }
+getrandom = { version = "0.2.12", features = ["js"] }
+serde = { workspace = true, features = ["derive"] }
+serde_tuple = { workspace = true  }
+num-traits = { workspace = true }
+num-derive = { workspace = true }
+
+
+[lib]
+crate-type = ["cdylib", "lib"]
diff --git a/fendermint/actors/chainmetadata/src/actor.rs b/fendermint/actors/chainmetadata/src/actor.rs
new file mode 100644
index 000000000..5bcc15257
--- /dev/null
+++ b/fendermint/actors/chainmetadata/src/actor.rs
@@ -0,0 +1,89 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+
+use cid::Cid;
+use fil_actors_runtime::actor_dispatch;
+use fil_actors_runtime::actor_error;
+use fil_actors_runtime::runtime::{ActorCode, Runtime};
+use fil_actors_runtime::ActorError;
+use fvm_ipld_encoding::tuple::{Deserialize_tuple, Serialize_tuple};
+use fvm_shared::METHOD_CONSTRUCTOR;
+use num_derive::FromPrimitive;
+use std::collections::VecDeque;
+
+#[derive(Serialize_tuple, Deserialize_tuple)]
+struct State {
+    blockhashes: VecDeque<Cid>,
+    params: ConstructorParams,
+}
+
+#[derive(Default, Debug, Serialize_tuple, Deserialize_tuple)]
+struct ConstructorParams {
+    lookback_len: u64,
+}
+
+#[derive(FromPrimitive)]
+#[repr(u64)]
+pub enum Method {
+    Constructor = METHOD_CONSTRUCTOR,
+    PushBlock = 2,
+    LookbackLen = 3,
+    BlockCID = 4,
+}
+
+pub struct Actor;
+
+impl Actor {
+    fn constructor(rt: &impl Runtime, params: ConstructorParams) -> Result<(), ActorError> {
+        let state = State {
+            blockhashes: VecDeque::new(),
+            params,
+        };
+        rt.create(&state)?;
+        Ok(())
+    }
+
+    fn push_block(rt: &impl Runtime, block: Cid) -> Result<(), ActorError> {
+        rt.transaction(|st: &mut State, _rt| {
+            st.blockhashes.push_back(block);
+            if st.blockhashes.len() > st.params.lookback_len as usize {
+                st.blockhashes.pop_front();
+            }
+
+            Ok(())
+        })?;
+
+        Ok(())
+    }
+
+    fn lookback_len(rt: &impl Runtime) -> Result<u64, ActorError> {
+        let state: State = rt.state()?;
+        Ok(state.params.lookback_len)
+    }
+
+    fn block_cid(rt: &impl Runtime, rewind: u64) -> Result<Cid, ActorError> {
+        let state: State = rt.state()?;
+        let block = state
+            .blockhashes
+            .get(state.blockhashes.len() - rewind as usize - 1)
+            .ok_or_else(|| actor_error!(illegal_argument; "lookback too large"))?;
+
+
+        Ok(*block)
+    }
+}
+
+impl ActorCode for Actor {
+    type Methods = Method;
+
+    fn name() -> &'static str {
+        "ChainMetadata"
+    }
+
+    actor_dispatch! {
+        Constructor => constructor,
+        PushBlock => push_block,
+        LookbackLen => lookback_len,
+        BlockCID => block_cid,
+    }
+}
diff --git a/fendermint/actors/chainmetadata/src/lib.rs b/fendermint/actors/chainmetadata/src/lib.rs
new file mode 100644
index 000000000..1d4daedef
--- /dev/null
+++ b/fendermint/actors/chainmetadata/src/lib.rs
@@ -0,0 +1,4 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+#[cfg(target_arch = "wasm32")]
+mod actor;
diff --git a/fendermint/actors/src/lib.rs b/fendermint/actors/src/lib.rs
new file mode 100644
index 000000000..f4a17876d
--- /dev/null
+++ b/fendermint/actors/src/lib.rs
@@ -0,0 +1,2 @@
+// Copyright 2022-2024 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
diff --git a/ipc/wallet/Cargo.toml b/ipc/wallet/Cargo.toml
index 6dc7365ad..11cd5d946 100644
--- a/ipc/wallet/Cargo.toml
+++ b/ipc/wallet/Cargo.toml
@@ -22,7 +22,7 @@ libsecp256k1 = { workspace = true }
 log = { workspace = true }
 rand = { workspace = true }
 serde = { workspace = true }
-serde_ipld_dagcbor = "0.2"
+serde_ipld_dagcbor = "0.4.2"
 serde_json = { workspace = true }
 thiserror = { workspace = true }
 xsalsa20poly1305 = "0.9"