walkero
/
nghttp2
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

nghttp2_session_mem_send: Handle stream closure early 

Previously session_after_frame_sent is called after we detected all
data is sent.  In nghttp2_session_mem_send, we only detect it in the
next call of the function.  It means that if a frame data bearing
END_STREAM is on flight to the peer as a result of
nghttp2_session_mem_send, peer may get that data and knows the stream
closure and issues new stream.  We may receive this new stream before
the next nghttp2_session_mem_send call, which means that we may
incorrectly assumes that peer violates maximum concurrent stream
limit.  To fix this issue, we separate session_after_frame_sent into 2
functions: session_after_frame_sent1 and session_after_frame_sent2.
session_after_frame_sent1 handles on_frame_send_callback and stream
closure and we call this early in nghttp2_session_mem_send.  This
makes number of streams are synchronized correctly with peer.
This commit is contained in:
Tatsuhiro Tsujikawa 2014-12-18 21:52:17 +09:00
parent ce1bf11d4b
commit 8bac2087cf
1 changed files with 107 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

127
lib/nghttp2_session.c
View File

@ -2200,7 +2200,10 @@ static void session_outbound_item_cycle_weight(nghttp2_session *session,
}
/*
* Called after a frame is sent.
* Called after a frame is sent. This function runs
* on_frame_send_callback and handles stream closure upon END_STREAM
* or RST_STREAM. This function does not reset session->aob. It is a
* responsibility of session_after_frame_sent2.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
@ -2210,7 +2213,7 @@ static void session_outbound_item_cycle_weight(nghttp2_session *session,
* NGHTTP2_ERR_CALLBACK_FAILURE
* The callback function failed.
*/
static int session_after_frame_sent(nghttp2_session *session) {
static int session_after_frame_sent1(nghttp2_session *session) {
int rv;
nghttp2_active_outbound_item *aob = &session->aob;
nghttp2_outbound_item *item = aob->item;
@ -2227,11 +2230,7 @@ static int session_after_frame_sent(nghttp2_session *session) {
frame->hd.type == NGHTTP2_PUSH_PROMISE) {
if (nghttp2_bufs_next_present(framebufs)) {
framebufs->cur = framebufs->cur->next;
DEBUGF(fprintf(stderr, "send: next CONTINUATION frame, %zu bytes\n",
nghttp2_buf_len(&framebufs->cur->buf)));
DEBUGF(fprintf(stderr, "send: CONTINUATION exists, just return\n"));
return 0;
}
}
@ -2242,8 +2241,9 @@ static int session_after_frame_sent(nghttp2_session *session) {
switch (frame->hd.type) {
case NGHTTP2_HEADERS: {
nghttp2_headers_aux_data *aux_data;
nghttp2_stream *stream =
nghttp2_session_get_stream(session, frame->hd.stream_id);
nghttp2_stream *stream;
stream = nghttp2_session_get_stream(session, frame->hd.stream_id);
if (!stream) {
break;
}
@ -2359,10 +2359,9 @@ static int session_after_frame_sent(nghttp2_session *session) {
default:
break;
}
active_outbound_item_reset(&session->aob, mem);
return 0;
} else {
nghttp2_outbound_item *next_item;
nghttp2_stream *stream;
nghttp2_data_aux_data *aux_data;
@ -2412,7 +2411,10 @@ static int session_after_frame_sent(nghttp2_session *session) {
stream = NULL;
}
}
} else if (session->callbacks.on_frame_send_callback) {
return 0;
}
if (session->callbacks.on_frame_send_callback) {
rv = session_call_on_frame_send(session, frame);
if (nghttp2_is_fatal(rv)) {
@ -2420,17 +2422,73 @@ static int session_after_frame_sent(nghttp2_session *session) {
}
}
/* On EOF, we have already detached data if stream is not NULL.
If stream is NULL, we cannot detach data. Please note that
return 0;
}
/* Unreachable */
assert(0);
return 0;
}
/*
* Called after a frame is sent and session_after_frame_sent1. This
* function is responsible to reset session->aob.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_CALLBACK_FAILURE
* The callback function failed.
*/
static int session_after_frame_sent2(nghttp2_session *session) {
int rv;
nghttp2_active_outbound_item *aob = &session->aob;
nghttp2_outbound_item *item = aob->item;
nghttp2_bufs *framebufs = &aob->framebufs;
nghttp2_frame *frame;
nghttp2_mem *mem;
mem = &session->mem;
frame = &item->frame;
if (frame->hd.type != NGHTTP2_DATA) {
if (frame->hd.type == NGHTTP2_HEADERS ||
frame->hd.type == NGHTTP2_PUSH_PROMISE) {
if (nghttp2_bufs_next_present(framebufs)) {
framebufs->cur = framebufs->cur->next;
DEBUGF(fprintf(stderr, "send: next CONTINUATION frame, %zu bytes\n",
nghttp2_buf_len(&framebufs->cur->buf)));
return 0;
}
}
active_outbound_item_reset(&session->aob, mem);
return 0;
} else {
nghttp2_outbound_item *next_item;
nghttp2_stream *stream;
nghttp2_data_aux_data *aux_data;
aux_data = &item->aux_data.data;
/* On EOF, we have already detached data. Please note that
application may issue nghttp2_submit_data() in
on_frame_send_callback, which attach data to stream. We don't
want to detach it. */
on_frame_send_callback (call from session_after_frame_sent1),
which attach data to stream. We don't want to detach it. */
if (aux_data->eof) {
active_outbound_item_reset(aob, mem);
return 0;
}
stream = nghttp2_session_get_stream(session, frame->hd.stream_id);
/* If session is closed or RST_STREAM was queued, we won't send
further data. */
if (nghttp2_session_predicate_data_send(session, stream) != 0) {
@ -2558,8 +2616,9 @@ static int session_after_frame_sent(nghttp2_session *session) {
return 0;
}
ssize_t nghttp2_session_mem_send(nghttp2_session *session,
const uint8_t **data_ptr) {
static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
const uint8_t **data_ptr,
int fast_cb) {
int rv;
nghttp2_active_outbound_item *aob;
nghttp2_bufs *framebufs;
@ -2680,7 +2739,12 @@ ssize_t nghttp2_session_mem_send(nghttp2_session *session,
DEBUGF(fprintf(stderr, "send: end transmission of a frame\n"));
/* Frame has completely sent */
rv = session_after_frame_sent(session);
if (fast_cb) {
rv = session_after_frame_sent2(session);
} else {
rv = session_after_frame_sent1(session);
rv = session_after_frame_sent2(session);
}
if (rv < 0) {
/* FATAL */
assert(nghttp2_is_fatal(rv));
@ -2703,6 +2767,29 @@ ssize_t nghttp2_session_mem_send(nghttp2_session *session,
}
}
ssize_t nghttp2_session_mem_send(nghttp2_session *session,
const uint8_t **data_ptr) {
int rv;
ssize_t len;
len = nghttp2_session_mem_send_internal(session, data_ptr, 1);
if (len <= 0) {
return len;
}
/* We have to call session_after_frame_sent1 here to handle stream
closure upon transmission of frames. Otherwise, END_STREAM may
be reached to client before we call nghttp2_session_mem_send
again and we may get exceeding number of incoming streams. */
rv = session_after_frame_sent1(session);
if (rv < 0) {
assert(nghttp2_is_fatal(rv));
return (ssize_t)rv;
}
return len;
}
int nghttp2_session_send(nghttp2_session *session) {
const uint8_t *data;
ssize_t datalen;
@ -2712,7 +2799,7 @@ int nghttp2_session_send(nghttp2_session *session) {
framebufs = &session->aob.framebufs;
for (;;) {
datalen = nghttp2_session_mem_send(session, &data);
datalen = nghttp2_session_mem_send_internal(session, &data, 0);
if (datalen <= 0) {
return (int)datalen;
}