use criterion::{criterion_group, criterion_main, Criterion}; use bytes::BytesMut; // A Miri run detects UB, seen on this playground: // https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=f5d9aa166aa48df8dca05fce2b6c3915 fn bench_header_parsing(c: &mut Criterion) { c.bench_function("Original (Unsound) [short]", |b| { b.iter(|| { let mut buf = BytesMut::from(REQ_SHORT); _original::parse_headers(&mut buf); }) }); c.bench_function("New (safe) [short]", |b| { b.iter(|| { let mut buf = BytesMut::from(REQ_SHORT); _new::parse_headers(&mut buf); }) }); c.bench_function("Original (Unsound) [realistic]", |b| { b.iter(|| { let mut buf = BytesMut::from(REQ); _original::parse_headers(&mut buf); }) }); c.bench_function("New (safe) [realistic]", |b| { b.iter(|| { let mut buf = BytesMut::from(REQ); _new::parse_headers(&mut buf); }) }); } criterion_group!(benches, bench_header_parsing); criterion_main!(benches); const MAX_HEADERS: usize = 96; const EMPTY_HEADER_ARRAY: [httparse::Header<'static>; MAX_HEADERS] = [httparse::EMPTY_HEADER; MAX_HEADERS]; #[derive(Clone, Copy)] struct HeaderIndex { name: (usize, usize), value: (usize, usize), } const EMPTY_HEADER_INDEX: HeaderIndex = HeaderIndex { name: (0, 0), value: (0, 0), }; const EMPTY_HEADER_INDEX_ARRAY: [HeaderIndex; MAX_HEADERS] = [EMPTY_HEADER_INDEX; MAX_HEADERS]; impl HeaderIndex { fn record( bytes: &[u8], headers: &[httparse::Header<'_>], indices: &mut [HeaderIndex], ) { let bytes_ptr = bytes.as_ptr() as usize; for (header, indices) in headers.iter().zip(indices.iter_mut()) { let name_start = header.name.as_ptr() as usize - bytes_ptr; let name_end = name_start + header.name.len(); indices.name = (name_start, name_end); let value_start = header.value.as_ptr() as usize - bytes_ptr; let value_end = value_start + header.value.len(); indices.value = (value_start, value_end); } } } // test cases taken from: // https://github.com/seanmonstar/httparse/blob/master/benches/parse.rs const REQ_SHORT: &[u8] = b"\ GET / HTTP/1.0\r\n\ Host: example.com\r\n\ Cookie: session=60; user_id=1\r\n\r\n"; const REQ: &[u8] = b"\ GET /wp-content/uploads/2010/03/hello-kitty-darth-vader-pink.jpg HTTP/1.1\r\n\ Host: www.kittyhell.com\r\n\ User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; ja-JP-mac; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 Pathtraq/0.9\r\n\ Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n\ Accept-Language: ja,en-us;q=0.7,en;q=0.3\r\n\ Accept-Encoding: gzip,deflate\r\n\ Accept-Charset: Shift_JIS,utf-8;q=0.7,*;q=0.7\r\n\ Keep-Alive: 115\r\n\ Connection: keep-alive\r\n\ Cookie: wp_ozh_wsa_visits=2; wp_ozh_wsa_visit_lasttime=xxxxxxxxxx; __utma=xxxxxxxxx.xxxxxxxxxx.xxxxxxxxxx.xxxxxxxxxx.xxxxxxxxxx.x; __utmz=xxxxxxxxx.xxxxxxxxxx.x.x.utmccn=(referral)|utmcsr=reader.livedoor.com|utmcct=/reader/|utmcmd=referral|padding=under256\r\n\r\n"; mod _new { use super::*; pub fn parse_headers(src: &mut BytesMut) -> usize { let mut headers: [HeaderIndex; MAX_HEADERS] = EMPTY_HEADER_INDEX_ARRAY; let mut parsed: [httparse::Header<'_>; MAX_HEADERS] = EMPTY_HEADER_ARRAY; let mut req = httparse::Request::new(&mut parsed); match req.parse(src).unwrap() { httparse::Status::Complete(_len) => { HeaderIndex::record(src, req.headers, &mut headers); req.headers.len() } _ => unreachable!(), } } } mod _original { use super::*; use std::mem::MaybeUninit; pub fn parse_headers(src: &mut BytesMut) -> usize { #![allow(clippy::uninit_assumed_init)] let mut headers: [HeaderIndex; MAX_HEADERS] = unsafe { MaybeUninit::uninit().assume_init() }; let mut parsed: [httparse::Header<'_>; MAX_HEADERS] = unsafe { MaybeUninit::uninit().assume_init() }; let mut req = httparse::Request::new(&mut parsed); match req.parse(src).unwrap() { httparse::Status::Complete(_len) => { HeaderIndex::record(src, req.headers, &mut headers); req.headers.len() } _ => unreachable!(), } } }