[PATCH 1 of 2] QUIC: reusable and idle modes for main connection

Sergey Kandaurov pluknet at nginx.com
Mon May 30 13:54:34 UTC 2022


> On 18 May 2022, at 10:57, Roman Arutyunyan <arut at nginx.com> wrote:
> 
> # HG changeset patch
> # User Roman Arutyunyan <arut at nginx.com>
> # Date 1652852691 -14400
> #      Wed May 18 09:44:51 2022 +0400
> # Branch quic
> # Node ID 67ae4b649f2e38a44b245b7a842cf396c8250f02
> # Parent  c2f5d79cde64457f1fa7344c56a5248a677a7e46
> QUIC: reusable and idle modes for main connection.
> 
> The modes are controlled by application layer.  For HTTP/3, they are enabled
> when there are no active request streams.
> 
> diff --git a/src/event/quic/ngx_event_quic.c b/src/event/quic/ngx_event_quic.c
> --- a/src/event/quic/ngx_event_quic.c
> +++ b/src/event/quic/ngx_event_quic.c
> @@ -414,8 +414,8 @@ ngx_quic_input_handler(ngx_event_t *rev)
>     }
> 
>     if (c->close) {
> -        qc->error_reason = "graceful shutdown";
> -        ngx_quic_close_connection(c, NGX_OK);
> +        qc->error = NGX_QUIC_ERR_NO_ERROR;
> +        ngx_quic_close_connection(c, NGX_ERROR);
>         return;
>     }
> 
> 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
> @@ -161,6 +161,7 @@ ngx_quic_close_streams(ngx_connection_t 
>     ngx_pool_t         *pool;
>     ngx_queue_t        *q;
>     ngx_rbtree_t       *tree;
> +    ngx_connection_t   *sc;
>     ngx_rbtree_node_t  *node;
>     ngx_quic_stream_t  *qs;
> 
> @@ -185,24 +186,41 @@ ngx_quic_close_streams(ngx_connection_t 
>         return NGX_OK;
>     }
> 
> -#if (NGX_DEBUG)
> -    ns = 0;
> -#endif
> -
>     node = ngx_rbtree_min(tree->root, tree->sentinel);
> 
>     while (node) {
>         qs = (ngx_quic_stream_t *) node;
>         node = ngx_rbtree_next(tree, node);
> +        sc = qs->connection;
> +
> +        if (sc == NULL) {
> +            ngx_quic_close_stream(qs);
> +            continue;
> +        }
> +
> +        if (c->close || sc->idle || sc->reusable) {
> +            sc->close = 1;
> +            sc->read->handler(sc->read);
> +        }
> +    }
> +
> +    if (tree->root == tree->sentinel) {
> +        return NGX_OK;
> +    }
> +
> +#if (NGX_DEBUG)
> +    ns = 0;
> +#endif
> +
> +    for (node = ngx_rbtree_min(tree->root, tree->sentinel);
> +         node;
> +         node = ngx_rbtree_next(tree, node))
> +    {
> +        qs = (ngx_quic_stream_t *) node;
> 
>         qs->recv_state = NGX_QUIC_STREAM_RECV_RESET_RECVD;
>         qs->send_state = NGX_QUIC_STREAM_SEND_RESET_SENT;
> 
> -        if (qs->connection == NULL) {
> -            ngx_quic_close_stream(qs);
> -            continue;
> -        }
> -
>         ngx_quic_set_event(qs->connection->read);
>         ngx_quic_set_event(qs->connection->write);
> 
> @@ -587,6 +605,7 @@ ngx_quic_create_stream(ngx_connection_t 
> {
>     ngx_log_t              *log;
>     ngx_pool_t             *pool;
> +    ngx_uint_t              reusable;
>     ngx_queue_t            *q;
>     ngx_connection_t       *sc;
>     ngx_quic_stream_t      *qs;
> @@ -639,7 +658,13 @@ ngx_quic_create_stream(ngx_connection_t 
>     *log = *c->log;
>     pool->log = log;
> 
> +    reusable = c->reusable;
> +    ngx_reusable_connection(c, 0);
> +
>     sc = ngx_get_connection(c->fd, log);
> +
> +    ngx_reusable_connection(c, reusable);
> +

jftr, this pollutes debug log a bit, but generally looks ok.

>     if (sc == NULL) {
>         ngx_destroy_pool(pool);
>         ngx_queue_insert_tail(&qc->streams.free, &qs->queue);
> diff --git a/src/http/v3/ngx_http_v3_request.c b/src/http/v3/ngx_http_v3_request.c
> --- a/src/http/v3/ngx_http_v3_request.c
> +++ b/src/http/v3/ngx_http_v3_request.c
> @@ -210,6 +210,11 @@ ngx_http_v3_init_request_stream(ngx_conn
> 
>     h3c = ngx_http_v3_get_session(c);
> 
> +    if (ngx_terminate || ngx_exiting) {
> +        h3c->goaway = 1;
> +        (void) ngx_http_v3_send_goaway(c, c->quic->id);
> +    }
> +

This results in ever increasing GOAWAY identifiers if multiple
new client streams received after graceful shutdown initiated.
This is forbidden per rfc9114, 5.2. Connection Shutdown.

I wonder if it should move after the below condition.

>     if (h3c->goaway) {
>         c->close = 1;
>         ngx_http_close_connection(c);
> @@ -258,7 +263,7 @@ ngx_http_v3_wait_request_handler(ngx_eve
>     size_t                     size;
>     ssize_t                    n;
>     ngx_buf_t                 *b;
> -    ngx_connection_t          *c;
> +    ngx_connection_t          *c, *pc;
>     ngx_pool_cleanup_t        *cln;
>     ngx_http_request_t        *r;
>     ngx_http_connection_t     *hc;
> @@ -385,6 +390,10 @@ ngx_http_v3_wait_request_handler(ngx_eve
>     h3c = ngx_http_v3_get_session(c);
>     h3c->nrequests++;
> 
> +    pc = c->quic->parent;
> +    pc->idle = 0;
> +    ngx_reusable_connection(pc, 0);
> +
>     if (h3c->keepalive.timer_set) {
>         ngx_del_timer(&h3c->keepalive);
>     }
> @@ -430,7 +439,7 @@ ngx_http_v3_cleanup_request(void *data)
> {
>     ngx_http_request_t  *r = data;
> 
> -    ngx_connection_t          *c;
> +    ngx_connection_t          *c, *pc;
>     ngx_http_v3_session_t     *h3c;
>     ngx_http_core_loc_conf_t  *clcf;
> 
> @@ -443,6 +452,16 @@ ngx_http_v3_cleanup_request(void *data)
>     h3c = ngx_http_v3_get_session(c);
> 
>     if (--h3c->nrequests == 0) {
> +        pc = c->quic->parent;
> +
> +        if (ngx_terminate || ngx_exiting) {
> +            ngx_quic_finalize_connection(pc, NGX_HTTP_V3_ERR_NO_ERROR, NULL);
> +            return;
> +        }
> +
> +        pc->idle = 1;
> +        ngx_reusable_connection(pc, 1);
> +
>         clcf = ngx_http_v3_get_module_loc_conf(c, ngx_http_core_module);
>         ngx_add_timer(&h3c->keepalive, clcf->keepalive_timeout);
>     }
> diff --git a/src/http/v3/ngx_http_v3_uni.c b/src/http/v3/ngx_http_v3_uni.c
> --- a/src/http/v3/ngx_http_v3_uni.c
> +++ b/src/http/v3/ngx_http_v3_uni.c
> @@ -182,6 +182,11 @@ ngx_http_v3_uni_read_handler(ngx_event_t
> 
>     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 read handler");
> 
> +    if (c->close) {
> +        ngx_http_v3_close_uni_stream(c);
> +        return;
> +    }
> +
>     ngx_memzero(&b, sizeof(ngx_buf_t));
> 
>     while (rev->ready) {
> @@ -262,6 +267,11 @@ ngx_http_v3_uni_dummy_read_handler(ngx_e
> 
>     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 dummy read handler");
> 
> +    if (c->close) {
> +        ngx_http_v3_close_uni_stream(c);
> +        return;
> +    }
> +
>     if (rev->ready) {
>         if (c->recv(c, &ch, 1) != 0) {
>             ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_NO_ERROR, NULL);
> 

-- 
Sergey Kandaurov



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