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Tidy inlined epee code in the RPC
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@kayabaNerve
kayabaNerve committed Jul 6, 2024
1 parent d847ec5 commit 0631607
Showing 1 changed file with 66 additions and 56 deletions.
122 changes: 66 additions & 56 deletions coins/monero/rpc/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -220,23 +220,6 @@ fn rpc_point(point: &str) -> Result<EdwardsPoint, RpcError> {
.ok_or_else(|| RpcError::InvalidNode(format!("invalid point: {point}")))
}

// Read an EPEE VarInt, distinct from the VarInts used throughout the rest of the protocol
fn read_epee_vi<R: io::Read>(reader: &mut R) -> io::Result<u64> {
let vi_start = read_byte(reader)?;
let len = match vi_start & 0b11 {
0 => 1,
1 => 2,
2 => 4,
3 => 8,
_ => unreachable!(),
};
let mut vi = u64::from(vi_start >> 2);
for i in 1 .. len {
vi |= u64::from(read_byte(reader)?) << (((i - 1) * 8) + 6);
}
Ok(vi)
}

/// An RPC connection to a Monero daemon.
///
/// This is abstract such that users can use an HTTP library (which being their choice), a
Expand Down Expand Up @@ -511,26 +494,29 @@ pub trait Rpc: Sync + Clone + Debug {

/// Get the output indexes of the specified transaction.
async fn get_o_indexes(&self, hash: [u8; 32]) -> Result<Vec<u64>, RpcError> {
/*
TODO: Use these when a suitable epee serde lib exists
#[derive(Serialize, Debug)]
struct Request {
txid: [u8; 32],
}
#[derive(Deserialize, Debug)]
struct OIndexes {
o_indexes: Vec<u64>,
}
*/

// Given the immaturity of Rust epee libraries, this is a homegrown one which is only validated
// to work against this specific function

// Header for EPEE, an 8-byte magic and a version
const EPEE_HEADER: &[u8] = b"\x01\x11\x01\x01\x01\x01\x02\x01\x01";

// Read an EPEE VarInt, distinct from the VarInts used throughout the rest of the protocol
fn read_epee_vi<R: io::Read>(reader: &mut R) -> io::Result<u64> {
let vi_start = read_byte(reader)?;
let len = match vi_start & 0b11 {
0 => 1,
1 => 2,
2 => 4,
3 => 8,
_ => unreachable!(),
};
let mut vi = u64::from(vi_start >> 2);
for i in 1 .. len {
vi |= u64::from(read_byte(reader)?) << (((i - 1) * 8) + 6);
}
Ok(vi)
}

let mut request = EPEE_HEADER.to_vec();
// Number of fields (shifted over 2 bits as the 2 LSBs are reserved for metadata)
request.push(1 << 2);
Expand All @@ -550,29 +536,58 @@ pub trait Rpc: Sync + Clone + Debug {

(|| {
let mut res = None;
let mut is_okay = false;
let mut has_status = false;

if read_bytes::<_, { EPEE_HEADER.len() }>(&mut indexes)? != EPEE_HEADER {
Err(io::Error::other("invalid header"))?;
}

let read_object = |reader: &mut &[u8]| -> io::Result<Vec<u64>> {
// Read the amount of fields
let fields = read_byte(reader)? >> 2;

for _ in 0 .. fields {
// Read the length of the field's name
let name_len = read_byte(reader)?;
// Read the name of the field
let name = read_raw_vec(read_byte, name_len.into(), reader)?;

let type_with_array_flag = read_byte(reader)?;
// The type of this field, without the potentially set array flag
let kind = type_with_array_flag & (!0x80);

let iters = if type_with_array_flag != kind { read_epee_vi(reader)? } else { 1 };

if (&name == b"o_indexes") && (kind != 5) {
Err(io::Error::other("o_indexes weren't u64s"))?;
let has_array_flag = type_with_array_flag != kind;

// Read this many instances of the field
let iters = if has_array_flag { read_epee_vi(reader)? } else { 1 };

// Check the field type
{
#[allow(clippy::match_same_arms)]
let (expected_type, expected_array_flag) = match name.as_slice() {
b"o_indexes" => (5, true),
b"status" => (10, false),
b"untrusted" => (11, false),
b"credits" => (5, false),
b"top_hash" => (10, false),
// On-purposely prints name as a byte vector to prevent printing arbitrary strings
// This is a self-describing format so we don't have to error here, yet we don't
// claim this to be a complete deserialization function
// To ensure it works for this specific use case, it's best to ensure it's limited
// to this specific use case (ensuring we have less variables to deal with)
_ => Err(io::Error::other(format!("unrecognized field in get_o_indexes: {name:?}")))?,
};
if (expected_type != kind) || (expected_array_flag != has_array_flag) {
let fmt_array_bool = |array_bool| if array_bool { "array" } else { "not array" };
Err(io::Error::other(format!(
"field {name:?} was {kind} ({}), expected {expected_type} ({})",
fmt_array_bool(has_array_flag),
fmt_array_bool(expected_array_flag)
)))?;
}
}

let f = match kind {
let read_field_as_bytes = match kind {
/*
// i64
1 => |reader: &mut &[u8]| read_raw_vec(read_byte, 8, reader),
// i32
Expand All @@ -581,8 +596,10 @@ pub trait Rpc: Sync + Clone + Debug {
3 => |reader: &mut &[u8]| read_raw_vec(read_byte, 2, reader),
// i8
4 => |reader: &mut &[u8]| read_raw_vec(read_byte, 1, reader),
*/
// u64
5 => |reader: &mut &[u8]| read_raw_vec(read_byte, 8, reader),
/*
// u32
6 => |reader: &mut &[u8]| read_raw_vec(read_byte, 4, reader),
// u16
Expand All @@ -591,6 +608,7 @@ pub trait Rpc: Sync + Clone + Debug {
8 => |reader: &mut &[u8]| read_raw_vec(read_byte, 1, reader),
// double
9 => |reader: &mut &[u8]| read_raw_vec(read_byte, 8, reader),
*/
// string, or any collection of bytes
10 => |reader: &mut &[u8]| {
let len = read_epee_vi(reader)?;
Expand All @@ -602,55 +620,47 @@ pub trait Rpc: Sync + Clone + Debug {
},
// bool
11 => |reader: &mut &[u8]| read_raw_vec(read_byte, 1, reader),
/*
// object, errors here as it shouldn't be used on this call
12 => {
|_: &mut &[u8]| Err(io::Error::other("node used object in reply to get_o_indexes"))
}
// array, so far unused
13 => |_: &mut &[u8]| Err(io::Error::other("node used the unused array type")),
*/
_ => |_: &mut &[u8]| Err(io::Error::other("node used an invalid type")),
};

let mut bytes_res = vec![];
for _ in 0 .. iters {
bytes_res.push(f(reader)?);
bytes_res.push(read_field_as_bytes(reader)?);
}

let mut actual_res = Vec::with_capacity(bytes_res.len());
match name.as_slice() {
b"o_indexes" => {
for o_index in bytes_res {
actual_res.push(u64::from_le_bytes(
o_index
.try_into()
.map_err(|_| io::Error::other("node didn't provide 8 bytes for a u64"))?,
));
actual_res.push(read_u64(&mut o_index.as_slice())?);
}
res = Some(actual_res);
}
b"status" => {
if bytes_res
.first()
.ok_or_else(|| io::Error::other("status wasn't a string"))?
.ok_or_else(|| io::Error::other("status was a 0-length array"))?
.as_slice() !=
b"OK"
{
// TODO: Better handle non-OK responses
Err(io::Error::other("response wasn't OK"))?;
}
is_okay = true;
has_status = true;
}
_ => continue,
}

if is_okay && res.is_some() {
break;
b"untrusted" | b"credits" | b"top_hash" => continue,
_ => Err(io::Error::other("unrecognized field in get_o_indexes"))?,
}
}

// Didn't return a response with a status
// (if the status wasn't okay, we would've already errored)
if !is_okay {
if !has_status {
Err(io::Error::other("response didn't contain a status"))?;
}

Expand All @@ -661,7 +671,7 @@ pub trait Rpc: Sync + Clone + Debug {

read_object(&mut indexes)
})()
.map_err(|_| RpcError::InvalidNode("invalid binary response".to_string()))
.map_err(|e| RpcError::InvalidNode(format!("invalid binary response: {e:?}")))
}

/// Get the output distribution.
Expand Down

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