[nginx] QUIC: congestion control in ngx_quic_frame_sendto().
Roman Arutyunyan
arut at nginx.com
Tue Dec 12 13:47:52 UTC 2023
details: https://hg.nginx.org/nginx/rev/efcdaa66df2e
branches:
changeset: 9192:efcdaa66df2e
user: Roman Arutyunyan <arut at nginx.com>
date: Wed Nov 29 21:41:29 2023 +0400
description:
QUIC: congestion control in ngx_quic_frame_sendto().
Previously ngx_quic_frame_sendto() ignored congestion control and did not
contribute to in_flight counter.
Now congestion control window is checked unless ignore_congestion flag is set.
Also, in_flight counter is incremented and the frame is stored in ctx->sent
queue if it's ack-eliciting. This behavior is now similar to
ngx_quic_output_packet().
diffstat:
src/event/quic/ngx_event_quic_ack.c | 32 ++++++++++----
src/event/quic/ngx_event_quic_migration.c | 51 ++++++++++++++----------
src/event/quic/ngx_event_quic_output.c | 65 ++++++++++++++++++++++++++----
src/event/quic/ngx_event_quic_transport.h | 1 +
4 files changed, 108 insertions(+), 41 deletions(-)
diffs (344 lines):
diff -r 618132842e7c -r efcdaa66df2e src/event/quic/ngx_event_quic_ack.c
--- a/src/event/quic/ngx_event_quic_ack.c Wed Nov 22 14:48:12 2023 +0400
+++ b/src/event/quic/ngx_event_quic_ack.c Wed Nov 29 21:41:29 2023 +0400
@@ -593,6 +593,7 @@ ngx_quic_resend_frames(ngx_connection_t
break;
case NGX_QUIC_FT_PING:
+ case NGX_QUIC_FT_PATH_CHALLENGE:
case NGX_QUIC_FT_PATH_RESPONSE:
case NGX_QUIC_FT_CONNECTION_CLOSE:
ngx_quic_free_frame(c, f);
@@ -824,11 +825,11 @@ void ngx_quic_lost_handler(ngx_event_t *
void
ngx_quic_pto_handler(ngx_event_t *ev)
{
- ngx_uint_t i;
+ ngx_uint_t i, n;
ngx_msec_t now;
ngx_queue_t *q;
ngx_connection_t *c;
- ngx_quic_frame_t *f, frame;
+ ngx_quic_frame_t *f;
ngx_quic_send_ctx_t *ctx;
ngx_quic_connection_t *qc;
@@ -865,16 +866,20 @@ ngx_quic_pto_handler(ngx_event_t *ev)
"quic pto %s pto_count:%ui",
ngx_quic_level_name(ctx->level), qc->pto_count);
- ngx_memzero(&frame, sizeof(ngx_quic_frame_t));
+ for (n = 0; n < 2; n++) {
- frame.level = ctx->level;
- frame.type = NGX_QUIC_FT_PING;
+ f = ngx_quic_alloc_frame(c);
+ if (f == NULL) {
+ goto failed;
+ }
- if (ngx_quic_frame_sendto(c, &frame, 0, qc->path) != NGX_OK
- || ngx_quic_frame_sendto(c, &frame, 0, qc->path) != NGX_OK)
- {
- ngx_quic_close_connection(c, NGX_ERROR);
- return;
+ f->level = ctx->level;
+ f->type = NGX_QUIC_FT_PING;
+ f->ignore_congestion = 1;
+
+ if (ngx_quic_frame_sendto(c, f, 0, qc->path) == NGX_ERROR) {
+ goto failed;
+ }
}
}
@@ -883,6 +888,13 @@ ngx_quic_pto_handler(ngx_event_t *ev)
ngx_quic_set_lost_timer(c);
ngx_quic_connstate_dbg(c);
+
+ return;
+
+failed:
+
+ ngx_quic_close_connection(c, NGX_ERROR);
+ return;
}
diff -r 618132842e7c -r efcdaa66df2e src/event/quic/ngx_event_quic_migration.c
--- a/src/event/quic/ngx_event_quic_migration.c Wed Nov 22 14:48:12 2023 +0400
+++ b/src/event/quic/ngx_event_quic_migration.c Wed Nov 29 21:41:29 2023 +0400
@@ -37,7 +37,7 @@ ngx_quic_handle_path_challenge_frame(ngx
ngx_quic_header_t *pkt, ngx_quic_path_challenge_frame_t *f)
{
size_t min;
- ngx_quic_frame_t frame, *fp;
+ ngx_quic_frame_t *fp;
ngx_quic_connection_t *qc;
if (pkt->level != ssl_encryption_application || pkt->path_challenged) {
@@ -50,11 +50,14 @@ ngx_quic_handle_path_challenge_frame(ngx
qc = ngx_quic_get_connection(c);
- ngx_memzero(&frame, sizeof(ngx_quic_frame_t));
+ fp = ngx_quic_alloc_frame(c);
+ if (fp == NULL) {
+ return NGX_ERROR;
+ }
- frame.level = ssl_encryption_application;
- frame.type = NGX_QUIC_FT_PATH_RESPONSE;
- frame.u.path_response = *f;
+ fp->level = ssl_encryption_application;
+ fp->type = NGX_QUIC_FT_PATH_RESPONSE;
+ fp->u.path_response = *f;
/*
* RFC 9000, 8.2.2. Path Validation Responses
@@ -73,7 +76,7 @@ ngx_quic_handle_path_challenge_frame(ngx
min = (ngx_quic_path_limit(c, pkt->path, 1200) < 1200) ? 0 : 1200;
- if (ngx_quic_frame_sendto(c, &frame, min, pkt->path) == NGX_ERROR) {
+ if (ngx_quic_frame_sendto(c, fp, min, pkt->path) == NGX_ERROR) {
return NGX_ERROR;
}
@@ -546,22 +549,25 @@ ngx_quic_validate_path(ngx_connection_t
static ngx_int_t
ngx_quic_send_path_challenge(ngx_connection_t *c, ngx_quic_path_t *path)
{
- size_t min;
- ngx_uint_t n;
- ngx_quic_frame_t frame;
+ size_t min;
+ ngx_uint_t n;
+ ngx_quic_frame_t *frame;
ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
"quic path seq:%uL send path_challenge tries:%ui",
path->seqnum, path->tries);
- ngx_memzero(&frame, sizeof(ngx_quic_frame_t));
-
- frame.level = ssl_encryption_application;
- frame.type = NGX_QUIC_FT_PATH_CHALLENGE;
-
for (n = 0; n < 2; n++) {
- ngx_memcpy(frame.u.path_challenge.data, path->challenge[n], 8);
+ frame = ngx_quic_alloc_frame(c);
+ if (frame == NULL) {
+ return NGX_ERROR;
+ }
+
+ frame->level = ssl_encryption_application;
+ frame->type = NGX_QUIC_FT_PATH_CHALLENGE;
+
+ ngx_memcpy(frame->u.path_challenge.data, path->challenge[n], 8);
/*
* RFC 9000, 8.2.1. Initiating Path Validation
@@ -574,7 +580,7 @@ ngx_quic_send_path_challenge(ngx_connect
min = (ngx_quic_path_limit(c, path, 1200) < 1200) ? 0 : 1200;
- if (ngx_quic_frame_sendto(c, &frame, min, path) == NGX_ERROR) {
+ if (ngx_quic_frame_sendto(c, frame, min, path) == NGX_ERROR) {
return NGX_ERROR;
}
}
@@ -883,14 +889,17 @@ ngx_quic_send_path_mtu_probe(ngx_connect
size_t mtu;
ngx_int_t rc;
ngx_uint_t log_error;
- ngx_quic_frame_t frame;
+ ngx_quic_frame_t *frame;
ngx_quic_send_ctx_t *ctx;
ngx_quic_connection_t *qc;
- ngx_memzero(&frame, sizeof(ngx_quic_frame_t));
+ frame = ngx_quic_alloc_frame(c);
+ if (frame == NULL) {
+ return NGX_ERROR;
+ }
- frame.level = ssl_encryption_application;
- frame.type = NGX_QUIC_FT_PING;
+ frame->level = ssl_encryption_application;
+ frame->type = NGX_QUIC_FT_PING;
qc = ngx_quic_get_connection(c);
ctx = ngx_quic_get_send_ctx(qc, ssl_encryption_application);
@@ -907,7 +916,7 @@ ngx_quic_send_path_mtu_probe(ngx_connect
mtu = path->mtu;
path->mtu = path->mtud;
- rc = ngx_quic_frame_sendto(c, &frame, path->mtud, path);
+ rc = ngx_quic_frame_sendto(c, frame, path->mtud, path);
path->mtu = mtu;
c->log_error = log_error;
diff -r 618132842e7c -r efcdaa66df2e src/event/quic/ngx_event_quic_output.c
--- a/src/event/quic/ngx_event_quic_output.c Wed Nov 22 14:48:12 2023 +0400
+++ b/src/event/quic/ngx_event_quic_output.c Wed Nov 29 21:41:29 2023 +0400
@@ -844,7 +844,7 @@ ngx_quic_send_stateless_reset(ngx_connec
ngx_int_t
ngx_quic_send_cc(ngx_connection_t *c)
{
- ngx_quic_frame_t frame;
+ ngx_quic_frame_t *frame;
ngx_quic_connection_t *qc;
qc = ngx_quic_get_connection(c);
@@ -860,22 +860,27 @@ ngx_quic_send_cc(ngx_connection_t *c)
return NGX_OK;
}
- ngx_memzero(&frame, sizeof(ngx_quic_frame_t));
+ frame = ngx_quic_alloc_frame(c);
+ if (frame == NULL) {
+ return NGX_ERROR;
+ }
- frame.level = qc->error_level;
- frame.type = qc->error_app ? NGX_QUIC_FT_CONNECTION_CLOSE_APP
- : NGX_QUIC_FT_CONNECTION_CLOSE;
- frame.u.close.error_code = qc->error;
- frame.u.close.frame_type = qc->error_ftype;
+ frame->level = qc->error_level;
+ frame->type = qc->error_app ? NGX_QUIC_FT_CONNECTION_CLOSE_APP
+ : NGX_QUIC_FT_CONNECTION_CLOSE;
+ frame->u.close.error_code = qc->error;
+ frame->u.close.frame_type = qc->error_ftype;
if (qc->error_reason) {
- frame.u.close.reason.len = ngx_strlen(qc->error_reason);
- frame.u.close.reason.data = (u_char *) qc->error_reason;
+ frame->u.close.reason.len = ngx_strlen(qc->error_reason);
+ frame->u.close.reason.data = (u_char *) qc->error_reason;
}
+ frame->ignore_congestion = 1;
+
qc->last_cc = ngx_current_msec;
- return ngx_quic_frame_sendto(c, &frame, 0, qc->path);
+ return ngx_quic_frame_sendto(c, frame, 0, qc->path);
}
@@ -1184,22 +1189,32 @@ ngx_quic_frame_sendto(ngx_connection_t *
size_t max, max_payload, min_payload, pad;
ssize_t len, sent;
ngx_str_t res;
+ ngx_msec_t now;
ngx_quic_header_t pkt;
ngx_quic_send_ctx_t *ctx;
+ ngx_quic_congestion_t *cg;
ngx_quic_connection_t *qc;
static u_char src[NGX_QUIC_MAX_UDP_PAYLOAD_SIZE];
static u_char dst[NGX_QUIC_MAX_UDP_PAYLOAD_SIZE];
qc = ngx_quic_get_connection(c);
+ cg = &qc->congestion;
ctx = ngx_quic_get_send_ctx(qc, frame->level);
+ now = ngx_current_msec;
+
max = ngx_quic_path_limit(c, path, path->mtu);
ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
"quic sendto %s packet max:%uz min:%uz",
ngx_quic_level_name(ctx->level), max, min);
+ if (cg->in_flight >= cg->window && !frame->ignore_congestion) {
+ ngx_quic_free_frame(c, frame);
+ return NGX_AGAIN;
+ }
+
ngx_quic_init_packet(c, ctx, &pkt, path);
min_payload = ngx_quic_payload_size(&pkt, min);
@@ -1210,6 +1225,7 @@ ngx_quic_frame_sendto(ngx_connection_t *
min_payload = ngx_max(min_payload, pad);
if (min_payload > max_payload) {
+ ngx_quic_free_frame(c, frame);
return NGX_AGAIN;
}
@@ -1221,11 +1237,13 @@ ngx_quic_frame_sendto(ngx_connection_t *
len = ngx_quic_create_frame(NULL, frame);
if ((size_t) len > max_payload) {
+ ngx_quic_free_frame(c, frame);
return NGX_AGAIN;
}
len = ngx_quic_create_frame(src, frame);
if (len == -1) {
+ ngx_quic_free_frame(c, frame);
return NGX_ERROR;
}
@@ -1242,18 +1260,45 @@ ngx_quic_frame_sendto(ngx_connection_t *
ngx_quic_log_packet(c->log, &pkt);
if (ngx_quic_encrypt(&pkt, &res) != NGX_OK) {
+ ngx_quic_free_frame(c, frame);
return NGX_ERROR;
}
+ frame->pnum = ctx->pnum;
+ frame->first = now;
+ frame->last = now;
+ frame->plen = res.len;
+
ctx->pnum++;
sent = ngx_quic_send(c, res.data, res.len, path->sockaddr, path->socklen);
if (sent < 0) {
+ ngx_quic_free_frame(c, frame);
return sent;
}
path->sent += sent;
+ if (frame->need_ack && !qc->closing) {
+ ngx_queue_insert_tail(&ctx->sent, &frame->queue);
+
+ cg->in_flight += frame->plen;
+
+ } else {
+ ngx_quic_free_frame(c, frame);
+ return NGX_OK;
+ }
+
+ ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
+ "quic congestion send if:%uz", cg->in_flight);
+
+ if (!qc->send_timer_set) {
+ qc->send_timer_set = 1;
+ ngx_add_timer(c->read, qc->tp.max_idle_timeout);
+ }
+
+ ngx_quic_set_lost_timer(c);
+
return NGX_OK;
}
diff -r 618132842e7c -r efcdaa66df2e src/event/quic/ngx_event_quic_transport.h
--- a/src/event/quic/ngx_event_quic_transport.h Wed Nov 22 14:48:12 2023 +0400
+++ b/src/event/quic/ngx_event_quic_transport.h Wed Nov 29 21:41:29 2023 +0400
@@ -271,6 +271,7 @@ struct ngx_quic_frame_s {
ssize_t len;
unsigned need_ack:1;
unsigned pkt_need_ack:1;
+ unsigned ignore_congestion:1;
ngx_chain_t *data;
union {
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