MEDIUM: h1: reimplement the http/1 response parser for the gateway
The HTTP/2->HTTP/1 gateway will need to process HTTP/1 responses. We
cannot sanely rely on the HTTP/1 txn to parse a response because :
1) responses generated by haproxy such as error messages, redirects,
stats or Lua are neither parsed nor indexed ; this could be
addressed over the long term but will take time.
2) the http txn is useless to parse the body : the states present there
are only meaningful to received bytes (ie next bytes to parse) and
not at all to sent bytes. Thus chunks cannot be followed at all.
Even when implementing this later, it's unsure whether it will be
possible when dealing with compression.
So using the HTTP txn is now out of the equation and the only remaining
solution is to call an HTTP/1 message parser. We already have one, it was
slightly modified to avoid keeping states by benefitting from the fact
that the response was produced by haproxy and this is entirely available.
It assumes the following rules are true, or that incuring an extra cost
to work around them is acceptable :
- the response buffer is read-write and supports modifications in place
- headers sent through / by haproxy are not folded. Folding is still
implemented by replacing CR/LF/tabs/spaces with spaces if encountered
- HTTP/0.9 responses are never sent by haproxy and have never been
supported at all
- haproxy will not send partial responses, the whole headers block will
be sent at once ; this means that we don't need to keep expensive
states and can afford to restart the parsing from the beginning when
facing a partial response ;
- response is contiguous (does not wrap). This was already the case
with the original parser and ensures we can safely dereference all
fields with (ptr,len)
The parser replaces all of the http_msg fields that were necessary with
local variables. The parser is not called on an http_msg but on a string
with a start and an end. The HTTP/1 states were reused for ease of use,
though the request-specific ones have not been implemented for now. The
error position and error state are supported and optional ; these ones
may be used later for bug hunting.
The parser issues the list of all the headers into a caller-allocated
array of struct ist.
The content-length/transfer-encoding header are checked and the relevant
info fed the h1 message state (flags + body_len).
diff --git a/include/proto/h1.h b/include/proto/h1.h
index 6bd7537..e7d364d 100644
--- a/include/proto/h1.h
+++ b/include/proto/h1.h
@@ -25,6 +25,7 @@
#include <common/buffer.h>
#include <common/compiler.h>
#include <common/config.h>
+#include <common/http-hdr.h>
#include <common/standard.h>
#include <types/h1.h>
#include <types/proto_http.h>
@@ -39,6 +40,9 @@
unsigned int *ret_ptr, enum h1_state *ret_state);
void http_msg_analyzer(struct http_msg *msg, struct hdr_idx *idx);
int http_forward_trailers(struct http_msg *msg);
+int h1_headers_to_hdr_list(char *start, const char *stop,
+ struct http_hdr *hdr, unsigned int hdr_num,
+ struct h1m *h1m);
#define H1_FLG_CTL 0x01
#define H1_FLG_SEP 0x02