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Fix local window size adjustments 

Now shrinking local window size properly limits the amount of
WINDOW_UPDATE value so that shrinked window is honored.
This commit is contained in:
Tatsuhiro Tsujikawa 2013-10-12 17:02:37 +09:00
parent 46de63b90b
commit e85418f045
11 changed files with 139 additions and 32 deletions
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5
lib/includes/nghttp2/nghttp2.h
View File

@ -1990,11 +1990,12 @@ int nghttp2_submit_goaway(nghttp2_session *session,
* should be submitted, then WINDOW_UPDATE is queued with the current
* received bytes count.
*
* If the |window_size_increment| is 0, the function does nothing and
* returns 0.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
* The |delta_window_size| is 0.
* :enum:`NGHTTP2_ERR_FLOW_CONTROL`
* The local window size overflow or gets negative.
* :enum:`NGHTTP2_ERR_STREAM_CLOSED`

43
lib/nghttp2_helper.c
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@ -94,25 +94,54 @@ void nghttp2_downcase(uint8_t *s, size_t len)
int nghttp2_adjust_local_window_size(int32_t *local_window_size_ptr,
int32_t *recv_window_size_ptr,
int32_t delta)
int32_t *recv_reduction_ptr,
int32_t *delta_ptr)
{
if(delta > 0) {
int32_t new_recv_window_size = *recv_window_size_ptr - delta;
if(*delta_ptr > 0) {
int32_t new_recv_window_size =
nghttp2_max(0, *recv_window_size_ptr) - *delta_ptr;
if(new_recv_window_size < 0) {
/* The delta size is strictly more than received bytes. Increase
local_window_size by that difference. */
int32_t recv_reduction_diff;
if(*local_window_size_ptr >
NGHTTP2_MAX_WINDOW_SIZE + new_recv_window_size) {
return NGHTTP2_ERR_FLOW_CONTROL;
}
*local_window_size_ptr -= new_recv_window_size;
new_recv_window_size = 0;
/* If there is recv_reduction due to earlier window_size
reduction, we have to adjust it too. */
recv_reduction_diff = nghttp2_min(*recv_reduction_ptr,
-new_recv_window_size);
*recv_reduction_ptr -= recv_reduction_diff;
if(*recv_window_size_ptr < 0) {
*recv_window_size_ptr += recv_reduction_diff;
} else {
/* If *recv_window_size_ptr > 0, then those bytes are
considered to be backed to the remote peer, so it is
effectively 0 now. */
*recv_window_size_ptr = recv_reduction_diff;
}
/* recv_reduction_diff must be paied from *delta_ptr, since it
was added in window size reduction (see below). */
*delta_ptr -= recv_reduction_diff;
} else {
*recv_window_size_ptr = new_recv_window_size;
}
*recv_window_size_ptr = new_recv_window_size;
return 0;
} else {
if(*local_window_size_ptr + delta < 0) {
if(*local_window_size_ptr + *delta_ptr < 0 ||
*recv_window_size_ptr < INT32_MIN - *delta_ptr ||
*recv_reduction_ptr > INT32_MAX + *delta_ptr) {
return NGHTTP2_ERR_FLOW_CONTROL;
}
*local_window_size_ptr += delta;
/* Decreasing local window size. Note that we achieve this without
noticing to the remote peer. To do this, we cut
recv_window_size by -delta. This means that we don't send
WINDOW_UPDATE for -delta bytes. */
*local_window_size_ptr += *delta_ptr;
*recv_window_size_ptr += *delta_ptr;
*recv_reduction_ptr -= *delta_ptr;
}
return 0;
}

14
lib/nghttp2_helper.h
View File

@ -92,11 +92,12 @@ void* nghttp2_memdup(const void* src, size_t n);
void nghttp2_downcase(uint8_t *s, size_t len);
/*
* Adjusts |*local_window_size_ptr| and |*recv_window_size_ptr| with
* |delta| which is the WINDOW_UPDATE's window_size_increment sent
* from local side. If |delta| is strictly larger than
* |*recv_window_size_ptr|, |*local_window_size_ptr| is increased by
* delta - *recv_window_size_ptr. If |delta| is negative,
* Adjusts |*local_window_size_ptr|, |*recv_window_size_ptr|,
* |*recv_reduction_ptr| with |*delta_ptr| which is the
* WINDOW_UPDATE's window_size_increment sent from local side. If
* |delta| is strictly larger than |*recv_window_size_ptr|,
* |*local_window_size_ptr| is increased by delta -
* *recv_window_size_ptr. If |delta| is negative,
* |*local_window_size_ptr| is decreased by delta.
*
* This function returns 0 if it succeeds, or one of the following
@ -107,7 +108,8 @@ void nghttp2_downcase(uint8_t *s, size_t len);
*/
int nghttp2_adjust_local_window_size(int32_t *local_window_size_ptr,
int32_t *recv_window_size_ptr,
int32_t delta);
int32_t *recv_reduction_ptr,
int32_t *delta_ptr);
/*
* Returns non-zero if the function decided that WINDOW_UPDATE should

1
lib/nghttp2_session.c
View File

@ -183,6 +183,7 @@ static int nghttp2_session_new(nghttp2_session **session_ptr,
(*session_ptr)->local_flow_control = 1;
(*session_ptr)->remote_window_size = NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE;
(*session_ptr)->recv_window_size = 0;
(*session_ptr)->recv_reduction = 0;
(*session_ptr)->local_window_size = NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE;
(*session_ptr)->goaway_flags = NGHTTP2_GOAWAY_NONE;

3
lib/nghttp2_session.h
View File

@ -173,6 +173,9 @@ struct nghttp2_session {
/* Keep track of the number of bytes received without
WINDOW_UPDATE. */
int32_t recv_window_size;
/* The amount of recv_window_size cut using submitting negative
value to WINDOW_UPDATE */
int32_t recv_reduction;
/* window size for local flow control. It is initially set to
NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE and could be
increased/decreased by submitting WINDOW_UPDATE. See

1
lib/nghttp2_stream.c
View File

@ -49,6 +49,7 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
stream->remote_window_size = remote_initial_window_size;
stream->local_window_size = local_initial_window_size;
stream->recv_window_size = 0;
stream->recv_reduction = 0;
}
void nghttp2_stream_free(nghttp2_stream *stream)

3
lib/nghttp2_stream.h
View File

@ -115,6 +115,9 @@ typedef struct {
/* Keep track of the number of bytes received without
WINDOW_UPDATE. */
int32_t recv_window_size;
/* The amount of recv_window_size cut using submitting negative
value to WINDOW_UPDATE */
int32_t recv_reduction;
/* window size for local flow control. It is initially set to
NGHTTP2_INITIAL_WINDOW_SIZE and could be increased/decreased by
submitting WINDOW_UPDATE. See nghttp2_submit_window_update(). */

8
lib/nghttp2_submit.c
View File

@ -285,7 +285,7 @@ int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags,
int rv;
nghttp2_stream *stream;
if(window_size_increment == 0) {
return NGHTTP2_ERR_INVALID_ARGUMENT;
return 0;
}
flags = 0;
if(stream_id == 0) {
@ -294,7 +294,8 @@ int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags,
}
rv = nghttp2_adjust_local_window_size(&session->local_window_size,
&session->recv_window_size,
window_size_increment);
&session->recv_reduction,
&window_size_increment);
if(rv != 0) {
return rv;
}
@ -314,7 +315,8 @@ int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags,
}
rv = nghttp2_adjust_local_window_size(&stream->local_window_size,
&stream->recv_window_size,
window_size_increment);
&stream->recv_reduction,
&window_size_increment);
if(rv != 0) {
return rv;
}

5
src/nghttp.cc
View File

@ -691,9 +691,10 @@ struct HttpClient {
}
}
if(config.connection_window_bits != -1) {
int32_t wininc = (1 << config.connection_window_bits) - 1
- NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE;
rv = nghttp2_submit_window_update
(session, NGHTTP2_FLAG_NONE, 0,
(1 << config.connection_window_bits) - 1);
(session, NGHTTP2_FLAG_NONE, 0, wininc);
if(rv != 0) {
return -1;
}

61
tests/nghttp2_helper_test.c
View File

@ -32,46 +32,93 @@ void test_nghttp2_adjust_local_window_size(void)
{
int32_t local_window_size = 100;
int32_t recv_window_size = 50;
int32_t recv_reduction = 0;
int32_t delta;
delta = 0;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size, 0));
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(50 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(0 == delta);
delta = 49;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size, 49));
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(1 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(49 == delta);
delta = 1;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size, 1));
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(0 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(1 == delta);
delta = 1;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size, 1));
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(101 == local_window_size);
CU_ASSERT(0 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(1 == delta);
delta = -1;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size, -1));
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(-1 == recv_window_size);
CU_ASSERT(1 == recv_reduction);
CU_ASSERT(-1 == delta);
delta = 1;
CU_ASSERT(0 == nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size,
&recv_reduction,
&delta));
CU_ASSERT(101 == local_window_size);
CU_ASSERT(0 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(0 == delta);
local_window_size = 100;
recv_window_size = 50;
recv_reduction = 0;
delta = INT32_MAX;
CU_ASSERT(NGHTTP2_ERR_FLOW_CONTROL ==
nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size,
INT32_MAX));
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(50 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(INT32_MAX == delta);
delta = INT32_MIN;
CU_ASSERT(NGHTTP2_ERR_FLOW_CONTROL ==
nghttp2_adjust_local_window_size(&local_window_size,
&recv_window_size,
INT32_MIN));
&recv_reduction,
&delta));
CU_ASSERT(100 == local_window_size);
CU_ASSERT(50 == recv_window_size);
CU_ASSERT(0 == recv_reduction);
CU_ASSERT(INT32_MIN == delta);
}
static int check_header_name(const char *s)

27
tests/nghttp2_session_test.c
View File

@ -2432,7 +2432,7 @@ void test_nghttp2_submit_window_update(void)
CU_ASSERT(0 == nghttp2_session_send(session));
CU_ASSERT(0 == stream->recv_window_size);
CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT ==
CU_ASSERT(0 ==
nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 2, 0));
/* Disable local flow control */
stream->local_flow_control = 0;
@ -2472,17 +2472,26 @@ void test_nghttp2_submit_window_update_local_window_size(void)
CU_ASSERT(0 == nghttp2_session_send(session));
/* Let's decrement local window size */
stream->recv_window_size = 32768;
stream->recv_window_size = 65536;
CU_ASSERT(0 == nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 2,
-stream->local_window_size / 2));
CU_ASSERT(32768 == stream->local_window_size);
CU_ASSERT(0 == stream->recv_window_size);
CU_ASSERT(32768 == stream->recv_reduction);
item = nghttp2_session_get_next_ob_item(session);
CU_ASSERT(NGHTTP2_WINDOW_UPDATE == OB_CTRL_TYPE(item));
CU_ASSERT(32768 == OB_CTRL(item)->window_update.window_size_increment);
CU_ASSERT(0 == nghttp2_session_send(session));
/* Increase local window size */
CU_ASSERT(0 == nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 2,
16384));
CU_ASSERT(49152 == stream->local_window_size);
CU_ASSERT(16384 == stream->recv_window_size);
CU_ASSERT(16384 == stream->recv_reduction);
CU_ASSERT(NULL == nghttp2_session_get_next_ob_item(session));
CU_ASSERT(NGHTTP2_ERR_FLOW_CONTROL ==
nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 2,
NGHTTP2_MAX_WINDOW_SIZE));
@ -2503,17 +2512,25 @@ void test_nghttp2_submit_window_update_local_window_size(void)
CU_ASSERT(0 == nghttp2_session_send(session));
/* Go decrement part */
session->recv_window_size = 32768;
session->recv_window_size = 65536;
CU_ASSERT(0 == nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 0,
-session->local_window_size/2));
CU_ASSERT(32768 == session->local_window_size);
CU_ASSERT(0 == session->recv_window_size);
CU_ASSERT(32768 == session->recv_reduction);
item = nghttp2_session_get_next_ob_item(session);
CU_ASSERT(NGHTTP2_WINDOW_UPDATE == OB_CTRL_TYPE(item));
CU_ASSERT(32768 == OB_CTRL(item)->window_update.window_size_increment);
CU_ASSERT(0 == nghttp2_session_send(session));
/* Increase local window size */
CU_ASSERT(0 == nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 0,
16384));
CU_ASSERT(49152 == session->local_window_size);
CU_ASSERT(16384 == session->recv_window_size);
CU_ASSERT(16384 == session->recv_reduction);
CU_ASSERT(NULL == nghttp2_session_get_next_ob_item(session));
CU_ASSERT(NGHTTP2_ERR_FLOW_CONTROL ==
nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 0,
NGHTTP2_MAX_WINDOW_SIZE));