From 9b13b1b712c6493f8d41fb3e3bc00fd2d160cd2b Mon Sep 17 00:00:00 2001
From: behzad nouri <behzadnouri@gmail.com>
Date: Tue, 17 May 2022 22:44:35 +0000
Subject: [PATCH] adds const_assert_eq for shred constants (#25288)

Adding const_assert_eq:
* Documents explicitly what the constants are equal to.
* Prevents introducing bugs by silently changing the constants as the
  code is updated.
---
 Cargo.lock              | 1 +
 ledger/Cargo.toml       | 1 +
 ledger/src/shred.rs     | 7 +++++++
 programs/bpf/Cargo.lock | 1 +
 4 files changed, 10 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 5fe3091a2..15c83ae5f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5132,6 +5132,7 @@ dependencies = [
  "solana-storage-proto",
  "solana-transaction-status",
  "solana-vote-program",
+ "static_assertions",
  "tempfile",
  "thiserror",
  "tokio",
diff --git a/ledger/Cargo.toml b/ledger/Cargo.toml
index 4f708c47a..acc326795 100644
--- a/ledger/Cargo.toml
+++ b/ledger/Cargo.toml
@@ -49,6 +49,7 @@ solana-storage-bigtable = { path = "../storage-bigtable", version = "=1.11.0" }
 solana-storage-proto = { path = "../storage-proto", version = "=1.11.0" }
 solana-transaction-status = { path = "../transaction-status", version = "=1.11.0" }
 solana-vote-program = { path = "../programs/vote", version = "=1.11.0" }
+static_assertions = "1.1.0"
 tempfile = "3.3.0"
 thiserror = "1.0"
 tokio = { version = "~1.14.1", features = ["full"] }
diff --git a/ledger/src/shred.rs b/ledger/src/shred.rs
index ec354929a..a5474c73f 100644
--- a/ledger/src/shred.rs
+++ b/ledger/src/shred.rs
@@ -67,6 +67,7 @@ use {
         pubkey::Pubkey,
         signature::{Keypair, Signature, Signer},
     },
+    static_assertions::const_assert_eq,
     std::{fmt::Debug, io::Cursor, mem::size_of, ops::RangeInclusive},
     thiserror::Error,
 };
@@ -84,13 +85,17 @@ const SIZE_OF_SHRED_TYPE: usize = 1;
 const SIZE_OF_SHRED_SLOT: usize = 8;
 const SIZE_OF_SHRED_INDEX: usize = 4;
 pub const SIZE_OF_NONCE: usize = 4;
+const_assert_eq!(SIZE_OF_CODING_SHRED_HEADERS, 89);
 const SIZE_OF_CODING_SHRED_HEADERS: usize =
     SIZE_OF_COMMON_SHRED_HEADER + SIZE_OF_CODING_SHRED_HEADER;
+// Maximum size of data that a data-shred may contain (excluding headers).
+const_assert_eq!(SIZE_OF_DATA_SHRED_PAYLOAD, 1051);
 pub const SIZE_OF_DATA_SHRED_PAYLOAD: usize = PACKET_DATA_SIZE
     - SIZE_OF_COMMON_SHRED_HEADER
     - SIZE_OF_DATA_SHRED_HEADER
     - SIZE_OF_CODING_SHRED_HEADERS
     - SIZE_OF_NONCE;
+const_assert_eq!(SHRED_DATA_OFFSET, 88);
 const SHRED_DATA_OFFSET: usize = SIZE_OF_COMMON_SHRED_HEADER + SIZE_OF_DATA_SHRED_HEADER;
 // DataShredHeader.size is sum of common-shred-header, data-shred-header and
 // data.len(). Broadcast stage may create zero length data shreds when the
@@ -102,9 +107,11 @@ const DATA_SHRED_SIZE_RANGE: RangeInclusive<usize> =
 const OFFSET_OF_SHRED_TYPE: usize = SIZE_OF_SIGNATURE;
 const OFFSET_OF_SHRED_SLOT: usize = SIZE_OF_SIGNATURE + SIZE_OF_SHRED_TYPE;
 const OFFSET_OF_SHRED_INDEX: usize = OFFSET_OF_SHRED_SLOT + SIZE_OF_SHRED_SLOT;
+const_assert_eq!(SHRED_PAYLOAD_SIZE, 1228);
 const SHRED_PAYLOAD_SIZE: usize = PACKET_DATA_SIZE - SIZE_OF_NONCE;
 // SIZE_OF_CODING_SHRED_HEADERS bytes at the end of data shreds
 // is never used and is not part of erasure coding.
+const_assert_eq!(ENCODED_PAYLOAD_SIZE, 1139);
 const ENCODED_PAYLOAD_SIZE: usize = SHRED_PAYLOAD_SIZE - SIZE_OF_CODING_SHRED_HEADERS;
 
 pub const MAX_DATA_SHREDS_PER_FEC_BLOCK: u32 = 32;
diff --git a/programs/bpf/Cargo.lock b/programs/bpf/Cargo.lock
index 5e0eb9d29..3e48ec31d 100644
--- a/programs/bpf/Cargo.lock
+++ b/programs/bpf/Cargo.lock
@@ -4679,6 +4679,7 @@ dependencies = [
  "solana-storage-proto",
  "solana-transaction-status",
  "solana-vote-program",
+ "static_assertions",
  "tempfile",
  "thiserror",
  "tokio",