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MINOR: filters/http: Slightly update the parsing of chunks 

Now, http_parse_chunk_size and http_skip_chunk_crlf return the number of bytes
parsed on success. http_skip_chunk_crlf does not use msg->sol anymore.

On the other hand, http_forward_trailers is unchanged. It returns >0 if the end
of trailers is reached and 0 if not. In all cases (except if an error is
encountered), msg->sol contains the length of the last parsed part of the
trailer headers.

Internal doc and comments about msg->sol has been updated accordingly.
This commit is contained in:
Christopher Faulet 2015-12-14 14:52:13 +01:00 committed by Willy Tarreau
parent b77c5c2693
commit 113f7decfc
3 changed files with 49 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
doc/internals/body-parsing.txt
View File

@ -87,7 +87,9 @@ msg.sol : start of line. Points to the beginning of the current header line
states starting with DATA. For chunked encoded messages, this sum
always corresponds to the beginning of the current chunk of data as
it appears in the buffer, or to be more precise, it corresponds to
the first of the remaining bytes of chunked data to be inspected.
the first of the remaining bytes of chunked data to be inspected. In
TRAILERS state, it contains the length of the last parsed part of
the trailer headers.
msg.eoh : end of headers. Points to the CRLF (or LF) preceeding the body and
marking the end of headers. It is where new headers are appended.

10
include/types/proto_http.h
View File

@ -296,10 +296,12 @@ enum {
* to a byte matching the current state.
*
* - sol (start of line) : start of current line before MSG_BODY. Starting
* from MSG_BODY, contains the length of the last
* parsed chunk size so that when added to sov it
* always points to the beginning of the current
* data chunk.
* from MSG_BODY and until MSG_TRAILERS, contains
* the length of the last parsed chunk size so that
* when added to sov it always points to the
* beginning of the current data chunk.
* in MSG_TRAILERS state, it contains the length of
* the last parsed part of the trailer headers.
*
* - eol (End of Line) : Before HTTP_MSG_BODY, relative offset in the
* buffer of the first byte which marks the end of

83
src/proto_http.c
View File

@ -2095,13 +2095,13 @@ void http_change_connection_header(struct http_txn *txn, struct http_msg *msg, i
return;
}
/* Parse the chunk size at msg->next. Once done, it adjusts ->next to point to
* the first byte of data after the chunk size, so that we know we can forward
* exactly msg->next bytes. msg->sol contains the exact number of bytes forming
* the chunk size. That way it is always possible to differentiate between the
* start of the body and the start of the data.
* Return >0 on success, 0 when some data is missing, <0 on error.
* Note: this function is designed to parse wrapped CRLF at the end of the buffer.
/* Parse the chunk size at msg->next. Once done, caller should adjust ->next to
* point to the first byte of data after the chunk size, so that we know we can
* forward exactly msg->next bytes. msg->sol contains the exact number of bytes
* forming the chunk size. That way it is always possible to differentiate
* between the start of the body and the start of the data. Return the number
* of byte parsed on success, 0 when some data is missing, <0 on error. Note:
* this function is designed to parse wrapped CRLF at the end of the buffer.
*/
static inline int http_parse_chunk_size(struct http_msg *msg)
{
@ -2181,40 +2181,42 @@ static inline int http_parse_chunk_size(struct http_msg *msg)
goto error;
}
/* OK we found our CRLF and now <ptr> points to the next byte,
* which may or may not be present. We save that into ->next,
* and the number of bytes parsed into msg->sol.
/* OK we found our CRLF and now <ptr> points to the next byte, which may
* or may not be present. We save the number of bytes parsed into
* msg->sol.
*/
msg->sol = ptr - ptr_old;
if (unlikely(ptr < ptr_old))
msg->sol += buf->size;
msg->chunk_len = chunk;
msg->body_len += chunk;
return 1;
return msg->sol;
error:
msg->err_pos = buffer_count(buf, buf->p, ptr);
return -1;
}
/* This function skips trailers in the buffer associated with HTTP
* message <msg>. The first visited position is msg->next. If the end of
* the trailers is found, it is automatically scheduled to be forwarded,
* msg->msg_state switches to HTTP_MSG_DONE, and the function returns >0.
* If not enough data are available, the function does not change anything
* except maybe msg->next if it could parse some lines, and returns zero.
* If a parse error is encountered, the function returns < 0 and does not
* change anything except maybe msg->next. Note that the message must
* already be in HTTP_MSG_TRAILERS state before calling this function,
* which implies that all non-trailers data have already been scheduled for
* forwarding, and that msg->next exactly matches the length of trailers
* already parsed and not forwarded. It is also important to note that this
* function is designed to be able to parse wrapped headers at end of buffer.
/* This function skips trailers in the buffer associated with HTTP message
* <msg>. The first visited position is msg->next. If the end of the trailers is
* found, the function returns >0. So, the caller can automatically schedul it
* to be forwarded, and switch msg->msg_state to HTTP_MSG_DONE. If not enough
* data are available, the function does not change anything except maybe
* msg->sol if it could parse some lines, and returns zero. If a parse error
* is encountered, the function returns < 0 and does not change anything except
* maybe msg->sol. Note that the message must already be in HTTP_MSG_TRAILERS
* state before calling this function, which implies that all non-trailers data
* have already been scheduled for forwarding, and that msg->next exactly
* matches the length of trailers already parsed and not forwarded. It is also
* important to note that this function is designed to be able to parse wrapped
* headers at end of buffer.
*/
static int http_forward_trailers(struct http_msg *msg)
{
const struct buffer *buf = msg->chn->buf;
/* we have msg->next which points to next line. Look for CRLF. */
/* we have msg->next which points to next line. Look for CRLF. But
* first, we reset msg->sol */
msg->sol = 0;
while (1) {
const char *p1 = NULL, *p2 = NULL;
const char *start = b_ptr(buf, msg->next + msg->sol);
@ -2267,15 +2269,15 @@ static int http_forward_trailers(struct http_msg *msg)
}
}
/* This function may be called only in HTTP_MSG_CHUNK_CRLF. It reads the CRLF
* or a possible LF alone at the end of a chunk. It automatically adjusts
* msg->next in order to include this part into the next forwarding phase.
* Note that the caller must ensure that ->p points to the first byte to parse.
* It also sets msg_state to HTTP_MSG_CHUNK_SIZE and returns >0 on success. If
* not enough data are available, the function does not change anything and
* returns zero. If a parse error is encountered, the function returns < 0 and
* does not change anything. Note: this function is designed to parse wrapped
* CRLF at the end of the buffer.
/* This function may be called only in HTTP_MSG_CHUNK_CRLF. It reads the CRLF or
* a possible LF alone at the end of a chunk. The caller should adjust msg->next
* in order to include this part into the next forwarding phase. Note that the
* caller must ensure that ->p points to the first byte to parse. It returns
* the number of bytes parsed on success, so the caller can set msg_state to
* HTTP_MSG_CHUNK_SIZE. If not enough data are available, the function does not
* change anything and returns zero. If a parse error is encountered, the
* function returns < 0. Note: this function is designed to parse wrapped CRLF
* at the end of the buffer.
*/
static inline int http_skip_chunk_crlf(struct http_msg *msg)
{
@ -2303,8 +2305,7 @@ static inline int http_skip_chunk_crlf(struct http_msg *msg)
msg->err_pos = buffer_count(buf, buf->p, ptr);
return -1;
}
msg->sol = bytes;
return 1;
return bytes;
}
/* Parses a qvalue and returns it multipled by 1000, from 0 to 1000. If the
@ -4760,8 +4761,7 @@ int http_wait_for_request_body(struct stream *s, struct channel *req, int an_bit
stream_inc_http_err_ctr(s);
goto return_bad_req;
}
msg->next += msg->sol;
msg->sol = 0;
msg->next += ret;
msg->msg_state = msg->chunk_len ? HTTP_MSG_DATA : HTTP_MSG_TRAILERS;
}
@ -6889,8 +6889,7 @@ http_msg_forward_chunked_body(struct stream *s, struct http_msg *msg)
goto missing_data_or_waiting;
if (ret < 0)
goto chunk_parsing_error;
msg->next += msg->sol;
msg->sol = 0;
msg->next += ret;
msg->msg_state = HTTP_MSG_CHUNK_SIZE;
/* fall through for HTTP_MSG_CHUNK_SIZE */
@ -6904,8 +6903,7 @@ http_msg_forward_chunked_body(struct stream *s, struct http_msg *msg)
goto missing_data_or_waiting;
if (ret < 0)
goto chunk_parsing_error;
msg->next += msg->sol;
msg->sol = 0;
msg->next += ret;
if (msg->chunk_len) {
msg->msg_state = HTTP_MSG_DATA;
goto switch_states;
@ -6921,7 +6919,6 @@ http_msg_forward_chunked_body(struct stream *s, struct http_msg *msg)
/* default_ret */ 1,
/* on_error */ goto error);
msg->next += msg->sol;
msg->sol = 0;
if (!ret)
goto missing_data_or_waiting;
break;