On Tue, Nov 16, 2021 at 12:18:47PM +0300, Vladimir Homutov wrote:
> On Mon, Nov 15, 2021 at 03:33:25PM +0300, Roman Arutyunyan wrote:
> > # HG changeset patch
> > # User Roman Arutyunyan <arut@nginx.com>
> > # Date 1636646820 -10800
> > # Thu Nov 11 19:07:00 2021 +0300
> > # Branch quic
> > # Node ID 801103b7645d93d0d06f63019e54d9e76f1baa6c
> > # Parent d2c193aa84800da00314f1af72ae722d964445a4
> > QUIC: reject streams which we could not create.
> >
> > The reasons why a stream may not be created by server currently include hitting
> > worker_connections limit and memory allocation error. Previously in these
> > cases the entire QUIC connection was closed and all its streams were shut down.
> > Now the new stream is rejected and existing streams continue working.
> >
> > To reject an HTTP/3 request stream, RESET_STREAM and STOP_SENDING with
> > H3_REQUEST_REJECTED error code are sent to client. HTTP/3 uni streams and
> > Stream streams are not rejected.
> >
> > diff --git a/src/event/quic/ngx_event_quic.h b/src/event/quic/ngx_event_quic.h
> > --- a/src/event/quic/ngx_event_quic.h
> > +++ b/src/event/quic/ngx_event_quic.h
> > @@ -61,6 +61,9 @@ typedef struct {
> > ngx_flag_t retry;
> > ngx_flag_t gso_enabled;
> > ngx_str_t host_key;
> > + ngx_int_t close_stream_code;
> > + ngx_int_t reject_uni_stream_code;
> > + ngx_int_t reject_bidi_stream_code;
>
> i would prefer stream_close_code and stream_reject_code_uni|bidi,
> a bit similar to transport parameter naming like
> 'initial_max_stream_data_bidi_local', YMMV

OK, let's do this.

> > u_char av_token_key[NGX_QUIC_AV_KEY_LEN];
> > u_char sr_token_key[NGX_QUIC_SR_KEY_LEN];
> > } ngx_quic_conf_t;
> > diff --git a/src/event/quic/ngx_event_quic_streams.c b/src/event/quic/ngx_event_quic_streams.c
> > --- a/src/event/quic/ngx_event_quic_streams.c
> > +++ b/src/event/quic/ngx_event_quic_streams.c
> > @@ -15,6 +15,7 @@
> >
> > static ngx_quic_stream_t *ngx_quic_create_client_stream(ngx_connection_t *c,
> > uint64_t id);
> > +static ngx_int_t ngx_quic_reject_stream(ngx_connection_t *c, uint64_t id);
> > static ngx_int_t ngx_quic_init_stream(ngx_quic_stream_t *qs);
> > static void ngx_quic_init_streams_handler(ngx_connection_t *c);
> > static ngx_quic_stream_t *ngx_quic_create_stream(ngx_connection_t *c,
> > @@ -377,8 +378,13 @@ ngx_quic_create_client_stream(ngx_connec
> > for ( /* void */ ; min_id < id; min_id += 0x04) {
> >
> > qs = ngx_quic_create_stream(c, min_id);
> > +
> > if (qs == NULL) {
> > - return NULL;
> > + if (ngx_quic_reject_stream(c, min_id) != NGX_OK) {
> > + return NULL;
> > + }
> > +
> > + continue;
> > }
> >
> > if (ngx_quic_init_stream(qs) != NGX_OK) {
> > @@ -390,7 +396,66 @@ ngx_quic_create_client_stream(ngx_connec
> > }
> > }
> >
> > - return ngx_quic_create_stream(c, id);
> > + qs = ngx_quic_create_stream(c, id);
> > +
> > + if (qs == NULL) {
> > + if (ngx_quic_reject_stream(c, id) != NGX_OK) {
> > + return NULL;
> > + }
> > +
> > + return NGX_QUIC_STREAM_GONE;
> > + }
> > +
> > + return qs;
> > +}
> > +
> > +
> > +static ngx_int_t
> > +ngx_quic_reject_stream(ngx_connection_t *c, uint64_t id)
> > +{
> > + uint64_t code;
> > + ngx_quic_frame_t *frame;
> > + ngx_quic_connection_t *qc;
> > +
> > + qc = ngx_quic_get_connection(c);
> > +
> > + code = (id & NGX_QUIC_STREAM_UNIDIRECTIONAL)
> > + ? qc->conf->reject_uni_stream_code
> > + : qc->conf->reject_bidi_stream_code;
> > +
> > + ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
> > + "quic stream id:0x%xL reject err:0x%xL", id, code);
>
> Here we may decline stream rejection, but have already logged it.
> I suggest putting debug below 'code == 0' test.

Zero code still carries some information. If it looks misleading, then yes,
let's move it below.

> > + if (code == 0) {
> > + return NGX_DECLINED;
> > + }
> > +
> > + frame = ngx_quic_alloc_frame(c);
> > + if (frame == NULL) {
> > + return NGX_ERROR;
> > + }
> > +
> > + frame->level = ssl_encryption_application;
> > + frame->type = NGX_QUIC_FT_RESET_STREAM;
> > + frame->u.reset_stream.id = id;
> > + frame->u.reset_stream.error_code = code;
> > + frame->u.reset_stream.final_size = 0;
> > +
> > + ngx_quic_queue_frame(qc, frame);
> > +
> > + frame = ngx_quic_alloc_frame(c);
> > + if (frame == NULL) {
> > + return NGX_ERROR;
> > + }
> > +
> > + frame->level = ssl_encryption_application;
> > + frame->type = NGX_QUIC_FT_STOP_SENDING;
> > + frame->u.stop_sending.id = id;
> > + frame->u.stop_sending.error_code = code;
> > +
> > + ngx_quic_queue_frame(qc, frame);
> > +
> > + return NGX_OK;
> > }
> >
> >
> > @@ -866,7 +931,9 @@ ngx_quic_stream_cleanup_handler(void *da
> > if ((qs->id & NGX_QUIC_STREAM_SERVER_INITIATED) == 0
> > || (qs->id & NGX_QUIC_STREAM_UNIDIRECTIONAL) == 0)
> > {
> > - if (!c->read->pending_eof && !c->read->error) {
> > + if (!c->read->pending_eof && !c->read->error
> > + && qc->conf->close_stream_code)
> > + {
> > frame = ngx_quic_alloc_frame(pc);
> > if (frame == NULL) {
> > goto done;
> > @@ -875,7 +942,7 @@ ngx_quic_stream_cleanup_handler(void *da
> > frame->level = ssl_encryption_application;
> > frame->type = NGX_QUIC_FT_STOP_SENDING;
> > frame->u.stop_sending.id = qs->id;
> > - frame->u.stop_sending.error_code = 0x100; /* HTTP/3 no error */
> > + frame->u.stop_sending.error_code = qc->conf->close_stream_code;
> >
> > ngx_quic_queue_frame(qc, frame);
> > }
> > diff --git a/src/http/modules/ngx_http_quic_module.c b/src/http/modules/ngx_http_quic_module.c
> > --- a/src/http/modules/ngx_http_quic_module.c
> > +++ b/src/http/modules/ngx_http_quic_module.c
> > @@ -314,6 +314,7 @@ ngx_http_quic_create_srv_conf(ngx_conf_t
> > * conf->tp.sr_enabled = 0
> > * conf->tp.preferred_address = NULL
> > * conf->host_key = { 0, NULL }
> > + * cong->reject_uni_stream_code = 0;
> > */
> >
> > conf->tp.max_idle_timeout = NGX_CONF_UNSET_MSEC;
> > @@ -331,6 +332,8 @@ ngx_http_quic_create_srv_conf(ngx_conf_t
> >
> > conf->retry = NGX_CONF_UNSET;
> > conf->gso_enabled = NGX_CONF_UNSET;
> > + conf->close_stream_code = NGX_HTTP_V3_ERR_NO_ERROR;
> > + conf->reject_bidi_stream_code = NGX_HTTP_V3_ERR_REQUEST_REJECTED;
> >
> > return conf;
> > }
> > diff --git a/src/stream/ngx_stream_quic_module.c b/src/stream/ngx_stream_quic_module.c
> > --- a/src/stream/ngx_stream_quic_module.c
> > +++ b/src/stream/ngx_stream_quic_module.c
> > @@ -241,6 +241,9 @@ ngx_stream_quic_create_srv_conf(ngx_conf
> > * conf->tp.retry_scid = { 0, NULL };
> > * conf->tp.preferred_address = NULL
> > * conf->host_key = { 0, NULL }
> > + * conf->close_stream_code = 0;
> > + * conf->reject_uni_stream_code = 0;
> > + * conf->reject_bidi_stream_code = 0;
> > */
> >
> > conf->tp.max_idle_timeout = NGX_CONF_UNSET_MSEC;
>
>
> Overal patch looks good to me
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> nginx-devel@nginx.org
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--
Roman Arutyunyan
# HG changeset patch
# User Roman Arutyunyan <arut@nginx.com>
# Date 1636646820 -10800
# Thu Nov 11 19:07:00 2021 +0300
# Branch quic
# Node ID 4ad8fc79cb33257c928a9098a87324b350576551
# Parent d2c193aa84800da00314f1af72ae722d964445a4
QUIC: reject streams which we could not create.

The reasons why a stream may not be created by server currently include hitting
worker_connections limit and memory allocation error. Previously in these
cases the entire QUIC connection was closed and all its streams were shut down.
Now the new stream is rejected and existing streams continue working.

To reject an HTTP/3 request stream, RESET_STREAM and STOP_SENDING with
H3_REQUEST_REJECTED error code are sent to client. HTTP/3 uni streams and
Stream streams are not rejected.

diff --git a/src/event/quic/ngx_event_quic.h b/src/event/quic/ngx_event_quic.h
--- a/src/event/quic/ngx_event_quic.h
+++ b/src/event/quic/ngx_event_quic.h
@@ -61,6 +61,9 @@ typedef struct {
ngx_flag_t retry;
ngx_flag_t gso_enabled;
ngx_str_t host_key;
+ ngx_int_t stream_close_code;
+ ngx_int_t stream_reject_code_uni;
+ ngx_int_t stream_reject_code_bidi;
u_char av_token_key[NGX_QUIC_AV_KEY_LEN];
u_char sr_token_key[NGX_QUIC_SR_KEY_LEN];
} ngx_quic_conf_t;
diff --git a/src/event/quic/ngx_event_quic_streams.c b/src/event/quic/ngx_event_quic_streams.c
--- a/src/event/quic/ngx_event_quic_streams.c
+++ b/src/event/quic/ngx_event_quic_streams.c
@@ -15,6 +15,7 @@

static ngx_quic_stream_t *ngx_quic_create_client_stream(ngx_connection_t *c,
uint64_t id);
+static ngx_int_t ngx_quic_reject_stream(ngx_connection_t *c, uint64_t id);
static ngx_int_t ngx_quic_init_stream(ngx_quic_stream_t *qs);
static void ngx_quic_init_streams_handler(ngx_connection_t *c);
static ngx_quic_stream_t *ngx_quic_create_stream(ngx_connection_t *c,
@@ -377,8 +378,13 @@ ngx_quic_create_client_stream(ngx_connec
for ( /* void */ ; min_id < id; min_id += 0x04) {

qs = ngx_quic_create_stream(c, min_id);
+
if (qs == NULL) {
- return NULL;
+ if (ngx_quic_reject_stream(c, min_id) != NGX_OK) {
+ return NULL;
+ }
+
+ continue;
}

if (ngx_quic_init_stream(qs) != NGX_OK) {
@@ -390,7 +396,66 @@ ngx_quic_create_client_stream(ngx_connec
}
}

- return ngx_quic_create_stream(c, id);
+ qs = ngx_quic_create_stream(c, id);
+
+ if (qs == NULL) {
+ if (ngx_quic_reject_stream(c, id) != NGX_OK) {
+ return NULL;
+ }
+
+ return NGX_QUIC_STREAM_GONE;
+ }
+
+ return qs;
+}
+
+
+static ngx_int_t
+ngx_quic_reject_stream(ngx_connection_t *c, uint64_t id)
+{
+ uint64_t code;
+ ngx_quic_frame_t *frame;
+ ngx_quic_connection_t *qc;
+
+ qc = ngx_quic_get_connection(c);
+
+ code = (id & NGX_QUIC_STREAM_UNIDIRECTIONAL)
+ ? qc->conf->stream_reject_code_uni
+ : qc->conf->stream_reject_code_bidi;
+
+ if (code == 0) {
+ return NGX_DECLINED;
+ }
+
+ ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
+ "quic stream id:0x%xL reject err:0x%xL", id, code);
+
+ frame = ngx_quic_alloc_frame(c);
+ if (frame == NULL) {
+ return NGX_ERROR;
+ }
+
+ frame->level = ssl_encryption_application;
+ frame->type = NGX_QUIC_FT_RESET_STREAM;
+ frame->u.reset_stream.id = id;
+ frame->u.reset_stream.error_code = code;
+ frame->u.reset_stream.final_size = 0;
+
+ ngx_quic_queue_frame(qc, frame);
+
+ frame = ngx_quic_alloc_frame(c);
+ if (frame == NULL) {
+ return NGX_ERROR;
+ }
+
+ frame->level = ssl_encryption_application;
+ frame->type = NGX_QUIC_FT_STOP_SENDING;
+ frame->u.stop_sending.id = id;
+ frame->u.stop_sending.error_code = code;
+
+ ngx_quic_queue_frame(qc, frame);
+
+ return NGX_OK;
}


@@ -866,7 +931,9 @@ ngx_quic_stream_cleanup_handler(void *da
if ((qs->id & NGX_QUIC_STREAM_SERVER_INITIATED) == 0
|| (qs->id & NGX_QUIC_STREAM_UNIDIRECTIONAL) == 0)
{
- if (!c->read->pending_eof && !c->read->error) {
+ if (!c->read->pending_eof && !c->read->error
+ && qc->conf->stream_close_code)
+ {
frame = ngx_quic_alloc_frame(pc);
if (frame == NULL) {
goto done;
@@ -875,7 +942,7 @@ ngx_quic_stream_cleanup_handler(void *da
frame->level = ssl_encryption_application;
frame->type = NGX_QUIC_FT_STOP_SENDING;
frame->u.stop_sending.id = qs->id;
- frame->u.stop_sending.error_code = 0x100; /* HTTP/3 no error */
+ frame->u.stop_sending.error_code = qc->conf->stream_close_code;

ngx_quic_queue_frame(qc, frame);
}
diff --git a/src/http/modules/ngx_http_quic_module.c b/src/http/modules/ngx_http_quic_module.c
--- a/src/http/modules/ngx_http_quic_module.c
+++ b/src/http/modules/ngx_http_quic_module.c
@@ -314,6 +314,7 @@ ngx_http_quic_create_srv_conf(ngx_conf_t
* conf->tp.sr_enabled = 0
* conf->tp.preferred_address = NULL
* conf->host_key = { 0, NULL }
+ * cong->stream_reject_code_uni = 0;
*/

conf->tp.max_idle_timeout = NGX_CONF_UNSET_MSEC;
@@ -331,6 +332,8 @@ ngx_http_quic_create_srv_conf(ngx_conf_t

conf->retry = NGX_CONF_UNSET;
conf->gso_enabled = NGX_CONF_UNSET;
+ conf->stream_close_code = NGX_HTTP_V3_ERR_NO_ERROR;
+ conf->stream_reject_code_bidi = NGX_HTTP_V3_ERR_REQUEST_REJECTED;

return conf;
}
diff --git a/src/stream/ngx_stream_quic_module.c b/src/stream/ngx_stream_quic_module.c
--- a/src/stream/ngx_stream_quic_module.c
+++ b/src/stream/ngx_stream_quic_module.c
@@ -241,6 +241,9 @@ ngx_stream_quic_create_srv_conf(ngx_conf
* conf->tp.retry_scid = { 0, NULL };
* conf->tp.preferred_address = NULL
* conf->host_key = { 0, NULL }
+ * conf->stream_close_code = 0;
+ * conf->stream_reject_code_uni = 0;
+ * conf->stream_reject_code_bidi= 0;
*/

conf->tp.max_idle_timeout = NGX_CONF_UNSET_MSEC;
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