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basic_parser optimizations:

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fix #185, fix #489

* SSE4.2 is detected

* basic_parser uses SSE4.2 if available

* basic_parser tries to parse on the initial buffer and if
  it does not find the end of header it shifts to a new
  strategy of waiting for the end of header to defeat
  slow loris attacks. This coincidentally is also faster
  than the previous algorithm.
This commit is contained in:
Vinnie Falco
2017-07-20 08:15:29 -07:00
parent c94821384d
commit e608acb791
11 changed files with 1733 additions and 1375 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/beast/http/impl/basic_parser.ipp
+224 -254
View File
@@ -21,40 +21,6 @@
namespace beast {
namespace http {
namespace detail {
template<class FwdIt>
inline
FwdIt
skip_ows2(FwdIt it, FwdIt const& end)
{
while(it != end)
{
if(*it != ' ' && *it != '\t')
break;
++it;
}
return it;
}
template<class RanIt>
inline
RanIt
skip_ows_rev2(
RanIt it, RanIt const& first)
{
while(it != first)
{
auto const c = it[-1];
if(c != ' ' && c != '\t')
break;
--it;
}
return it;
}
} // detail
template<bool isRequest, class Derived>
basic_parser<isRequest, Derived>::
basic_parser()
@@ -177,6 +143,7 @@ put(boost::asio::const_buffers_1 const& buffer,
auto n = buffer_size(*buffer.begin());
auto const p0 = p;
auto const p1 = p0 + n;
ec.assign(0, ec.category());
loop:
switch(state_)
{
@@ -186,16 +153,67 @@ loop:
ec = error::need_more;
return 0;
}
state_ = state::header;
state_ = state::start_line;
BEAST_FALLTHROUGH;
case state::header:
parse_header(p, n, ec);
case state::start_line:
{
maybe_need_more(p, n, ec);
if(ec)
goto done;
parse_start_line(p, p + std::min<std::size_t>(
header_limit_, n), ec, is_request{});
if(ec)
{
if(ec == error::need_more)
{
if(n >= header_limit_)
{
ec = error::header_limit;
goto done;
}
if(p + 3 <= p1)
skip_ = static_cast<
std::size_t>(p1 - p - 3);
}
goto done;
}
BOOST_ASSERT(! is_done());
n = static_cast<std::size_t>(p1 - p);
if(p >= p1)
{
ec = error::need_more;
goto done;
}
BEAST_FALLTHROUGH;
}
case state::fields:
maybe_need_more(p, n, ec);
if(ec)
goto done;
parse_fields(p, p + std::min<std::size_t>(
header_limit_, n), ec);
if(ec)
{
if(ec == error::need_more)
{
if(n >= header_limit_)
{
ec = error::header_limit;
goto done;
}
if(p + 3 <= p1)
skip_ = static_cast<
std::size_t>(p1 - p - 3);
}
goto done;
}
finish_header(ec, is_request{});
break;
case state::body0:
BOOST_ASSERT(! skip_);
impl().on_body(content_length(), ec);
if(ec)
goto done;
@@ -203,12 +221,14 @@ loop:
BEAST_FALLTHROUGH;
case state::body:
BOOST_ASSERT(! skip_);
parse_body(p, n, ec);
if(ec)
goto done;
break;
case state::body_to_eof0:
BOOST_ASSERT(! skip_);
impl().on_body(content_length(), ec);
if(ec)
goto done;
@@ -216,6 +236,7 @@ loop:
BEAST_FALLTHROUGH;
case state::body_to_eof:
BOOST_ASSERT(! skip_);
parse_body_to_eof(p, n, ec);
if(ec)
goto done;
@@ -259,7 +280,8 @@ basic_parser<isRequest, Derived>::
put_eof(error_code& ec)
{
BOOST_ASSERT(got_some());
if(state_ == state::header)
if( state_ == state::start_line ||
state_ == state::fields)
{
ec = error::partial_message;
return;
@@ -300,9 +322,12 @@ template<bool isRequest, class Derived>
inline
void
basic_parser<isRequest, Derived>::
parse_header(char const*& p,
std::size_t n, error_code& ec)
maybe_need_more(
char const* p, std::size_t n,
error_code& ec)
{
if(skip_ == 0)
return;
if( n > header_limit_)
n = header_limit_;
if(n < skip_ + 4)
@@ -320,73 +345,57 @@ parse_header(char const*& p,
ec = error::header_limit;
return;
}
ec = http::error::need_more;
ec = error::need_more;
return;
}
skip_ = 0;
parse_header(p, term, ec,
std::integral_constant<bool, isRequest>{});
if(ec)
return;
impl().on_header(ec);
if(ec)
return;
if(state_ == state::complete)
{
impl().on_complete(ec);
if(ec)
return;
}
}
template<bool isRequest, class Derived>
inline
void
basic_parser<isRequest, Derived>::
parse_header(char const*& p, char const* term,
parse_start_line(
char const*& in, char const* last,
error_code& ec, std::true_type)
{
/*
request-line = method SP request-target SP HTTP-version CRLF
method = token
*/
auto const method = parse_method(p);
if(method.empty())
{
ec = error::bad_method;
return;
}
if(*p++ != ' ')
{
ec = error::bad_method;
return;
}
auto p = in;
auto const target = parse_target(p);
if(target.empty())
{
ec = error::bad_target;
string_view method;
parse_method(p, last, method, ec);
if(ec)
return;
}
if(*p++ != ' ')
{
ec = error::bad_target;
return;
}
auto const version = parse_version(p);
if(version < 0)
string_view target;
parse_target(p, last, target, ec);
if(ec)
return;
int version;
parse_version(p, last, version, ec);
if(ec)
return;
if(version < 10 || version > 11)
{
ec = error::bad_version;
return;
}
if(! parse_crlf(p))
if(p + 2 > last)
{
ec = error::need_more;
return;
}
if(p[0] != '\r' || p[1] != '\n')
{
ec = error::bad_version;
return;
}
p += 2;
if(version >= 11)
f_ |= flagHTTP11;
@@ -396,11 +405,114 @@ parse_header(char const*& p, char const* term,
if(ec)
return;
parse_fields(p, term, ec);
in = p;
state_ = state::fields;
}
template<bool isRequest, class Derived>
inline
void
basic_parser<isRequest, Derived>::
parse_start_line(
char const*& in, char const* last,
error_code& ec, std::false_type)
{
/*
status-line = HTTP-version SP status-code SP reason-phrase CRLF
status-code = 3*DIGIT
reason-phrase = *( HTAB / SP / VCHAR / obs-text )
*/
auto p = in;
int version;
parse_version(p, last, version, ec);
if(ec)
return;
BOOST_ASSERT(p == term);
if(version < 10 || version > 11)
{
ec = error::bad_version;
return;
}
// SP
if(p + 1 > last)
{
ec = error::need_more;
return;
}
if(*p++ != ' ')
{
ec = error::bad_version;
return;
}
parse_status(p, last, status_, ec);
if(ec)
return;
// parse reason CRLF
string_view reason;
parse_reason(p, last, reason, ec);
if(ec)
return;
if(version >= 11)
f_ |= flagHTTP11;
impl().on_response(
status_, reason, version, ec);
if(ec)
return;
in = p;
state_ = state::fields;
}
template<bool isRequest, class Derived>
void
basic_parser<isRequest, Derived>::
parse_fields(char const*& in,
char const* last, error_code& ec)
{
string_view name;
string_view value;
// https://stackoverflow.com/questions/686217/maximum-on-http-header-values
static_string<max_obs_fold> buf;
auto p = in;
for(;;)
{
if(p + 2 > last)
{
ec = error::need_more;
return;
}
if(p[0] == '\r')
{
if(p[1] != '\n')
ec = error::bad_line_ending;
in = p + 2;
return;
}
parse_field(p, last, name, value, buf, ec);
if(ec)
return;
auto const f = string_to_field(name);
do_field(f, value, ec);
if(ec)
return;
impl().on_field(f, name, value, ec);
if(ec)
return;
in = p;
}
}
template<bool isRequest, class Derived>
inline
void
basic_parser<isRequest, Derived>::
finish_header(error_code& ec, std::true_type)
{
// RFC 7230 section 3.3
// https://tools.ietf.org/html/rfc7230#section-3.3
@@ -430,62 +542,31 @@ parse_header(char const*& p, char const* term,
len_ = 0;
state_ = state::complete;
}
impl().on_header(ec);
if(ec)
return;
if(state_ == state::complete)
{
impl().on_complete(ec);
if(ec)
return;
}
}
template<bool isRequest, class Derived>
inline
void
basic_parser<isRequest, Derived>::
parse_header(char const*& p, char const* term,
error_code& ec, std::false_type)
finish_header(error_code& ec, std::false_type)
{
/*
status-line = HTTP-version SP status-code SP reason-phrase CRLF
status-code = 3*DIGIT
reason-phrase = *( HTAB / SP / VCHAR / obs-text )
*/
auto const version = parse_version(p);
if(version < 0 || *p != ' ')
{
ec = error::bad_version;
return;
}
++p;
auto const status = parse_status(p);
if(status < 0 || *p != ' ')
{
ec = error::bad_status;
return;
}
++p;
auto const reason = parse_reason(p);
if(! parse_crlf(p))
{
ec = error::bad_reason;
return;
}
if(version >= 11)
f_ |= flagHTTP11;
impl().on_response(
status, reason, version, ec);
if(ec)
return;
parse_fields(p, term, ec);
if(ec)
return;
BOOST_ASSERT(p == term);
// RFC 7230 section 3.3
// https://tools.ietf.org/html/rfc7230#section-3.3
if( (f_ & flagSkipBody) || // e.g. response to a HEAD request
status / 100 == 1 || // 1xx e.g. Continue
status == 204 || // No Content
status == 304) // Not Modified
status_ / 100 == 1 || // 1xx e.g. Continue
status_ == 204 || // No Content
status_ == 304) // Not Modified
{
state_ = state::complete;
return;
@@ -514,6 +595,16 @@ parse_header(char const*& p, char const* term,
f_ |= flagNeedEOF;
state_ = state::body_to_eof0;
}
impl().on_header(ec);
if(ec)
return;
if(state_ == state::complete)
{
impl().on_complete(ec);
if(ec)
return;
}
}
template<bool isRequest, class Derived>
@@ -712,117 +803,6 @@ parse_chunk_body(char const*& p,
state_ = state::chunk_header;
}
template<bool isRequest, class Derived>
void
basic_parser<isRequest, Derived>::
parse_fields(char const*& p,
char const* last, error_code& ec)
{
/* header-field = field-name ":" OWS field-value OWS
field-name = token
field-value = *( field-content / obs-fold )
field-content = field-vchar [ 1*( SP / HTAB ) field-vchar ]
field-vchar = VCHAR / obs-text
obs-fold = CRLF 1*( SP / HTAB )
; obsolete line folding
; see Section 3.2.4
*/
for(;;)
{
auto term = find_eol(p, last, ec);
if(ec)
return;
BOOST_ASSERT(term);
if(p == term - 2)
{
p = term;
break;
}
auto const name = parse_name(p);
if(name.empty())
{
ec = error::bad_field;
return;
}
if(*p++ != ':')
{
ec = error::bad_field;
return;
}
if(*term != ' ' &&
*term != '\t')
{
auto it2 = term - 2;
p = detail::skip_ows2(p, it2);
it2 = detail::skip_ows_rev2(it2, p);
auto const f = string_to_field(name);
auto const value = make_string(p, it2);
do_field(f, value, ec);
if(ec)
return;
impl().on_field(f, name, value, ec);
if(ec)
return;
p = term;
}
else
{
// obs-fold
for(;;)
{
auto const it2 = term - 2;
p = detail::skip_ows2(p, it2);
if(p != it2)
break;
p = term;
if(*p != ' ' && *p != '\t')
break;
term = find_eol(p, last, ec);
if(ec)
return;
}
// https://stackoverflow.com/questions/686217/maximum-on-http-header-values
static_string<max_obs_fold> s;
try
{
if(p != term)
{
s.append(p, term - 2);
p = term;
for(;;)
{
if(*p != ' ' && *p != '\t')
break;
s.push_back(' ');
p = detail::skip_ows2(p, term - 2);
term = find_eol(p, last, ec);
if(ec)
return;
if(p != term - 2)
s.append(p, term - 2);
p = term;
}
}
}
catch(std::length_error const&)
{
ec = error::bad_obs_fold;
return;
}
auto const f = string_to_field(name);
string_view const value{s.data(), s.size()};
do_field(f, value, ec);
if(ec)
return;
impl().on_field(f, name, value, ec);
if(ec)
return;
}
}
}
template<bool isRequest, class Derived>
void
basic_parser<isRequest, Derived>::
@@ -842,19 +822,19 @@ do_field(field f,
}
for(auto const& s : list)
{
if(strieq("close", s))
if(iequals({"close", 5}, s))
{
f_ |= flagConnectionClose;
continue;
}
if(strieq("keep-alive", s))
if(iequals({"keep-alive", 10}, s))
{
f_ |= flagConnectionKeepAlive;
continue;
}
if(strieq("upgrade", s))
if(iequals({"upgrade", 7}, s))
{
f_ |= flagConnectionUpgrade;
continue;
@@ -864,16 +844,6 @@ do_field(field f,
return;
}
for(auto p = value.begin();
p != value.end(); ++p)
{
if(! is_text(*p))
{
ec = error::bad_value;
return;
}
}
// Content-Length
if(f == field::content_length)
{
@@ -933,7 +903,7 @@ do_field(field f,
auto const p = std::find_if(v.begin(), v.end(),
[&](typename token_list::value_type const& s)
{
return strieq("chunked", s);
return iequals({"chunked", 7}, s);
});
if(p == v.end())
return;