QUIC: sending probe packets on PTO timer expiration.
The PTO handler is split into separate PTO and loss detection handlers that operate interchangeably depending on which timer should be set. The present ngx_quic_lost_handler is now only used for packet loss detection. It replaces ngx_quic_pto_handler if there are packets preceeding largest_ack. Once there is no more such packets, ngx_quic_pto_handler is installed again. Probes carry unacknowledged data previously sent in the oldest packet number, one per each packet number space. That is, it could be up to two probes. PTO backoff is now increased before scheduling next probes.
This commit is contained in:
Sergey Kandaurov
parent
89121eccf7
commit
8402cb2f3e
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@ -265,7 +265,10 @@ static ngx_int_t ngx_quic_send_frames(ngx_connection_t *c,
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static void ngx_quic_set_packet_number(ngx_quic_header_t *pkt,
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ngx_quic_send_ctx_t *ctx);
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static void ngx_quic_pto_handler(ngx_event_t *ev);
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static ngx_int_t ngx_quic_detect_lost(ngx_connection_t *c, ngx_uint_t ack);
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static void ngx_quic_lost_handler(ngx_event_t *ev);
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static ngx_int_t ngx_quic_detect_lost(ngx_connection_t *c);
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static ngx_int_t ngx_quic_resend_frames(ngx_connection_t *c,
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ngx_quic_send_ctx_t *ctx, ngx_quic_frame_t *start);
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static void ngx_quic_push_handler(ngx_event_t *ev);
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static void ngx_quic_rbtree_insert_stream(ngx_rbtree_node_t *temp,
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@ -2401,7 +2404,7 @@ ngx_quic_handle_ack_frame(ngx_connection_t *c, ngx_quic_header_t *pkt,
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}
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}
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return ngx_quic_detect_lost(c, 1);
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return ngx_quic_detect_lost(c);
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}
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@ -3682,18 +3685,46 @@ ngx_quic_set_packet_number(ngx_quic_header_t *pkt, ngx_quic_send_ctx_t *ctx)
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static void
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ngx_quic_pto_handler(ngx_event_t *ev)
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{
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ngx_connection_t *c;
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ngx_uint_t i;
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ngx_queue_t *q;
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ngx_connection_t *c;
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ngx_quic_frame_t *start;
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ngx_quic_send_ctx_t *ctx;
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ngx_quic_connection_t *qc;
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ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, 0, "quic pto timer");
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c = ev->data;
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qc = c->quic;
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if (ngx_quic_detect_lost(c, 0) != NGX_OK) {
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ngx_quic_close_connection(c, NGX_ERROR);
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return;
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qc->pto_count++;
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for (i = 0; i < NGX_QUIC_SEND_CTX_LAST; i++) {
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ctx = &qc->send_ctx[i];
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if (ngx_queue_empty(&ctx->sent)) {
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continue;
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}
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q = ngx_queue_head(&ctx->sent);
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start = ngx_queue_data(q, ngx_quic_frame_t, queue);
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if (start->pnum <= ctx->largest_ack
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&& ctx->largest_ack != (uint64_t) -1)
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{
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continue;
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}
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ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
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"quic pto pnum:%ui pto_count:%ui level:%d",
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start->pnum, c->quic->pto_count, start->level);
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if (ngx_quic_resend_frames(c, ctx, start) != NGX_OK) {
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ngx_quic_close_connection(c, NGX_ERROR);
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return;
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}
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}
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c->quic->pto_count++;
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}
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@ -3713,14 +3744,28 @@ ngx_quic_push_handler(ngx_event_t *ev)
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}
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static ngx_int_t
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ngx_quic_detect_lost(ngx_connection_t *c, ngx_uint_t ack)
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static
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void ngx_quic_lost_handler(ngx_event_t *ev)
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{
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ngx_connection_t *c;
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ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, 0, "quic lost timer");
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c = ev->data;
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if (ngx_quic_detect_lost(c) != NGX_OK) {
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ngx_quic_close_connection(c, NGX_ERROR);
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}
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}
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static ngx_int_t
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ngx_quic_detect_lost(ngx_connection_t *c)
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{
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uint64_t pn;
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ngx_uint_t i;
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ngx_msec_t now, wait, min_wait, thr;
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ngx_queue_t *q, range;
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ngx_quic_frame_t *f, *start;
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ngx_queue_t *q;
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ngx_quic_frame_t *start;
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ngx_quic_send_ctx_t *ctx;
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ngx_quic_connection_t *qc;
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@ -3729,91 +3774,96 @@ ngx_quic_detect_lost(ngx_connection_t *c, ngx_uint_t ack)
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min_wait = 0;
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#if (NGX_SUPPRESS_WARN)
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thr = 0;
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#endif
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if (ack) {
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thr = NGX_QUIC_TIME_THR * ngx_max(qc->latest_rtt, qc->avg_rtt);
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thr = ngx_max(thr, NGX_QUIC_TIME_GRANULARITY);
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}
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thr = NGX_QUIC_TIME_THR * ngx_max(qc->latest_rtt, qc->avg_rtt);
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thr = ngx_max(thr, NGX_QUIC_TIME_GRANULARITY);
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for (i = 0; i < NGX_QUIC_SEND_CTX_LAST; i++) {
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ctx = &qc->send_ctx[i];
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if (ngx_queue_empty(&ctx->sent)) {
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continue;
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}
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while (!ngx_queue_empty(&ctx->sent)) {
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if (!ack) {
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thr = ngx_quic_pto(c, ctx);
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}
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q = ngx_queue_head(&ctx->sent);
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do {
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q = ngx_queue_head(&ctx->sent);
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start = ngx_queue_data(q, ngx_quic_frame_t, queue);
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wait = start->last + thr - now;
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ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
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"quic detect_lost pnum:%ui thr:%M wait:%i level:%d",
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start->pnum, thr, (ngx_int_t) wait, start->level);
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if ((ngx_msec_int_t) wait >= 0) {
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if (min_wait == 0 || wait < min_wait) {
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min_wait = wait;
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}
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if (!ack) {
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break;
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}
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if ((start->pnum > ctx->largest_ack)
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|| ctx->largest_ack == (uint64_t) -1
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|| ((ctx->largest_ack - start->pnum) < NGX_QUIC_PKT_THR))
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{
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break;
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}
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}
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pn = start->pnum;
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ngx_queue_init(&range);
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/* send frames with same packet number to the wire */
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do {
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f = ngx_queue_data(q, ngx_quic_frame_t, queue);
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if (f->pnum != pn) {
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break;
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}
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q = ngx_queue_next(q);
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ngx_queue_remove(&f->queue);
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ngx_queue_insert_tail(&range, &f->queue);
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} while (q != ngx_queue_sentinel(&ctx->sent));
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ngx_quic_congestion_lost(c, start);
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if (ngx_quic_send_frames(c, ctx, &range) != NGX_OK) {
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if (ngx_quic_resend_frames(c, ctx, start) != NGX_OK) {
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return NGX_ERROR;
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}
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} while (q != ngx_queue_sentinel(&ctx->sent));
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}
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}
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/* no more preceeding packets */
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if (min_wait == 0) {
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qc->pto.handler = ngx_quic_pto_handler;
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return NGX_OK;
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}
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qc->pto.handler = ngx_quic_lost_handler;
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if (qc->pto.timer_set) {
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ngx_del_timer(&qc->pto);
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}
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if (min_wait > 0) {
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ngx_add_timer(&qc->pto, min_wait);
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}
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ngx_add_timer(&qc->pto, min_wait);
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return NGX_OK;
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}
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static ngx_int_t
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ngx_quic_resend_frames(ngx_connection_t *c, ngx_quic_send_ctx_t *ctx,
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ngx_quic_frame_t *start)
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{
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ngx_queue_t *q, range;
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ngx_quic_frame_t *f;
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ngx_queue_init(&range);
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/* send frames with same packet number to the wire */
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q = ngx_queue_head(&ctx->sent);
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do {
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f = ngx_queue_data(q, ngx_quic_frame_t, queue);
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if (f->pnum != start->pnum) {
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break;
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}
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q = ngx_queue_next(q);
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ngx_queue_remove(&f->queue);
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ngx_queue_insert_tail(&range, &f->queue);
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} while (q != ngx_queue_sentinel(&ctx->sent));
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ngx_quic_congestion_lost(c, start);
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return ngx_quic_send_frames(c, ctx, &range);
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}
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ngx_connection_t *
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ngx_quic_open_stream(ngx_connection_t *c, ngx_uint_t bidi)
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{
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