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checked request for OnDemand

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This commit is contained in:
Robert Habermeier
2017-04-05 18:56:01 +02:00
parent 35740456a4
commit 08d8709ef6
4 changed files with 232 additions and 47 deletions
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165
ethcore/light/src/on_demand/request.rs
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@@ -26,17 +26,171 @@ use ethcore::receipt::Receipt;
use ethcore::state::{self, ProvedExecution};
use ethcore::transaction::SignedTransaction;
use request::{self as net_request, IncompleteRequest, Output, OutputKind};
use rlp::{RlpStream, UntrustedRlp};
use util::{Address, Bytes, DBValue, HashDB, H256, U256};
use util::memorydb::MemoryDB;
use util::sha3::Hashable;
use util::trie::{Trie, TrieDB, TrieError};
/// Core unit of the API: submit batches of these to be answered with `Response`s.
pub enum Request {
/// A request for a header proof.
HeaderProof(HeaderProof),
/// A request for a header by hash.
HeaderByHash(HeaderByHash),
/// A request for block receipts.
Receipts(BlockReceipts),
/// A request for a block body.
Body(Body),
/// A request for an account.
Account(Account),
/// A request for a contract's code.
Code(Code),
/// A request for proof of execution.
Execution(TransactionProof),
}
/// Requests coupled with their required data for verification.
/// This is used internally but not part of the public API.
#[derive(Clone)]
#[allow(missing_docs)]
pub enum CheckedRequest {
HeaderProof(HeaderProof, net_request::IncompleteHeaderProofRequest),
HeaderByHash(HeaderByHash, net_request::IncompleteHeadersRequest),
Receipts(BlockReceipts, net_request::IncompleteReceiptsRequest),
Body(Body, net_request::IncompleteBodyRequest),
Account(Account, net_request::IncompleteAccountRequest),
Code(Code, net_request::IncompleteCodeRequest),
Execution(TransactionProof, net_request::IncompleteExecutionRequest),
}
impl IncompleteRequest for CheckedRequest {
type Complete = net_request::CompleteRequest;
type Response = net_request::Response;
/// Check prior outputs against the needed inputs.
///
/// This is called to ensure consistency of this request with
/// others in the same packet.
fn check_outputs<F>(&self, f: F) -> Result<(), net_request::NoSuchOutput>
where F: FnMut(usize, usize, OutputKind) -> Result<(), net_request::NoSuchOutput>
{
match *self {
CheckedRequest::HeaderProof(_, ref req) => req.check_outputs(f),
CheckedRequest::HeaderByHash(_, ref req) => req.check_outputs(f),
CheckedRequest::Receipts(_, ref req) => req.check_outputs(f),
CheckedRequest::Body(_, ref req) => req.check_outputs(f),
CheckedRequest::Account(_, ref req) => req.check_outputs(f),
CheckedRequest::Code(_, ref req) => req.check_outputs(f),
CheckedRequest::Execution(_, ref req) => req.check_outputs(f),
}
}
/// Note that this request will produce the following outputs.
fn note_outputs<F>(&self, f: F) where F: FnMut(usize, OutputKind) {
match *self {
CheckedRequest::HeaderProof(_, ref req) => req.note_outputs(f),
CheckedRequest::HeaderByHash(_, ref req) => req.note_outputs(f),
CheckedRequest::Receipts(_, ref req) => req.note_outputs(f),
CheckedRequest::Body(_, ref req) => req.note_outputs(f),
CheckedRequest::Account(_, ref req) => req.note_outputs(f),
CheckedRequest::Code(_, ref req) => req.note_outputs(f),
CheckedRequest::Execution(_, ref req) => req.note_outputs(f),
}
}
/// Fill fields of the request.
///
/// This function is provided an "output oracle" which allows fetching of
/// prior request outputs.
/// Only outputs previously checked with `check_outputs` may be available.
fn fill<F>(&mut self, f: F) where F: Fn(usize, usize) -> Result<Output, net_request::NoSuchOutput> {
match *self {
CheckedRequest::HeaderProof(_, ref mut req) => req.fill(f),
CheckedRequest::HeaderByHash(_, ref mut req) => req.fill(f),
CheckedRequest::Receipts(_, ref mut req) => req.fill(f),
CheckedRequest::Body(_, ref mut req) => req.fill(f),
CheckedRequest::Account(_, ref mut req) => req.fill(f),
CheckedRequest::Code(_, ref mut req) => req.fill(f),
CheckedRequest::Execution(_, ref mut req) => req.fill(f),
}
}
/// Will succeed if all fields have been filled, will fail otherwise.
fn complete(self) -> Result<Self::Complete, net_request::NoSuchOutput> {
use ::request::CompleteRequest;
match self {
CheckedRequest::HeaderProof(_, req) => req.complete().map(CompleteRequest::HeaderProof),
CheckedRequest::HeaderByHash(_, req) => req.complete().map(CompleteRequest::Headers),
CheckedRequest::Receipts(_, req) => req.complete().map(CompleteRequest::Receipts),
CheckedRequest::Body(_, req) => req.complete().map(CompleteRequest::Body),
CheckedRequest::Account(_, req) => req.complete().map(CompleteRequest::Account),
CheckedRequest::Code(_, req) => req.complete().map(CompleteRequest::Code),
CheckedRequest::Execution(_, req) => req.complete().map(CompleteRequest::Execution),
}
}
}
impl net_request::CheckedRequest for CheckedRequest {
type Extract = Response;
type Error = Error;
/// Check whether the response matches (beyond the type).
fn check_response(&self, response: &Self::Response) -> Result<Response, Error> {
use ::request::Response as NetResponse;
// check response against contained prover.
match (self, response) {
(&CheckedRequest::HeaderProof(ref prover, _), &NetResponse::HeaderProof(ref res)) =>
prover.check_response(&res.proof).map(|(h, s)| Response::HeaderProof(h, s)),
(&CheckedRequest::HeaderByHash(ref prover, _), &NetResponse::Headers(ref res)) =>
prover.check_response(&res.headers).map(Response::HeaderByHash),
(&CheckedRequest::Receipts(ref prover, _), &NetResponse::Receipts(ref res)) =>
prover.check_response(&res.receipts).map(Response::Receipts),
(&CheckedRequest::Body(ref prover, _), &NetResponse::Body(ref res)) =>
prover.check_response(&res.body).map(Response::Body),
(&CheckedRequest::Account(ref prover, _), &NetResponse::Account(ref res)) =>
prover.check_response(&res.proof).map(Response::Account),
(&CheckedRequest::Code(ref prover, _), &NetResponse::Code(ref res)) =>
prover.check_response(&res.code).map(Response::Code),
(&CheckedRequest::Execution(ref prover, _), &NetResponse::Execution(ref res)) =>
Ok(Response::Execution(prover.check_response(&res.items))),
_ => Err(Error::WrongKind),
}
}
}
/// Responses to on-demand requests.
/// All of these are checked.
pub enum Response {
/// Response to a header proof request.
/// Returns the hash and chain score.
HeaderProof(H256, U256),
/// Response to a header-by-hash request.
HeaderByHash(encoded::Header),
/// Response to a receipts request.
Receipts(Vec<Receipt>),
/// Response to a block body request.
Body(encoded::Block),
/// Response to an Account request.
// TODO: `unwrap_or(engine_defaults)`
Account(Option<BasicAccount>),
/// Response to a request for code.
Code(Vec<u8>),
/// Response to a request for proved execution.
Execution(ProvedExecution), // TODO: make into `Result`
}
/// Errors in verification.
#[derive(Debug, PartialEq)]
pub enum Error {
/// RLP decoder error.
Decoder(::rlp::DecoderError),
/// Empty response.
Empty,
/// Trie lookup error (result of bad proof)
Trie(TrieError),
/// Bad inclusion proof
@@ -47,6 +201,8 @@ pub enum Error {
WrongHash(H256, H256),
/// Wrong trie root.
WrongTrieRoot(H256, H256),
/// Wrong response kind.
WrongKind,
}
impl From<::rlp::DecoderError> for Error {
@@ -107,7 +263,8 @@ pub struct HeaderByHash(pub H256);
impl HeaderByHash {
/// Check a response for the header.
pub fn check_response(&self, header: &encoded::Header) -> Result<encoded::Header, Error> {
pub fn check_response(&self, headers: &[encoded::Header]) -> Result<encoded::Header, Error> {
let header = headers.get(0).ok_or(Error::Empty)?;
let hash = header.sha3();
match hash == self.0 {
true => Ok(header.clone()),
@@ -208,6 +365,7 @@ impl Account {
}
/// Request for account code.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Code {
/// Block hash, number pair.
pub block_id: (H256, u64),
@@ -217,10 +375,10 @@ pub struct Code {
impl Code {
/// Check a response with code against the code hash.
pub fn check_response(&self, code: &[u8]) -> Result<(), Error> {
pub fn check_response(&self, code: &[u8]) -> Result<Vec<u8>, Error> {
let found_hash = code.sha3();
if found_hash == self.code_hash {
Ok(())
Ok(code.to_vec())
} else {
Err(Error::WrongHash(self.code_hash, found_hash))
}
@@ -228,6 +386,7 @@ impl Code {
}
/// Request for transaction execution, along with the parts necessary to verify the proof.
#[derive(Clone)]
pub struct TransactionProof {
/// The transaction to request proof of.
pub tx: SignedTransaction,