[PATCH 2 of 3] HTTP/2: "http2" directive

Sergey Kandaurov pluknet at nginx.com
Tue Feb 7 10:25:20 UTC 2023


> On 1 Feb 2023, at 18:01, Roman Arutyunyan <arut at nginx.com> wrote:
> 
> # HG changeset patch
> # User Roman Arutyunyan <arut at nginx.com>
> # Date 1675255790 -14400
> #      Wed Feb 01 16:49:50 2023 +0400
> # Branch quic
> # Node ID 139b348815b3f19753176988f06b590a3e0af4c0
> # Parent  2fcc1c60be1c89aad5464bcc06f1189d1adc885a
> HTTP/2: "http2" directive.
> 
> The directive enables HTTP/2 in the current server.  The previous way to
> enable HTTP/2 via "listen ... http2" is now deprecated.
> 
> diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
> --- a/src/http/modules/ngx_http_ssl_module.c
> +++ b/src/http/modules/ngx_http_ssl_module.c
> @@ -427,6 +427,9 @@ ngx_http_ssl_alpn_select(ngx_ssl_conn_t 
> #if (NGX_HTTP_V2 || NGX_HTTP_V3)
>     ngx_http_connection_t   *hc;
> #endif
> +#if (NGX_HTTP_V2)
> +    ngx_http_v2_srv_conf_t  *h2scf;
> +#endif
> #if (NGX_HTTP_V3)
>     ngx_http_v3_srv_conf_t  *h3scf;
> #endif
> @@ -448,12 +451,9 @@ ngx_http_ssl_alpn_select(ngx_ssl_conn_t 
>     hc = c->data;
> #endif
> 
> -#if (NGX_HTTP_V2)
> -    if (hc->addr_conf->http2) {
> -        srv = (unsigned char *) NGX_HTTP_V2_ALPN_PROTO NGX_HTTP_ALPN_PROTOS;
> -        srvlen = sizeof(NGX_HTTP_V2_ALPN_PROTO NGX_HTTP_ALPN_PROTOS) - 1;
> -    } else
> -#endif
> +    srv = (unsigned char *) NGX_HTTP_ALPN_PROTOS;
> +    srvlen = sizeof(NGX_HTTP_ALPN_PROTOS) - 1;
> +
> #if (NGX_HTTP_V3)
>     if (hc->addr_conf->quic) {
> 
> @@ -479,10 +479,16 @@ ngx_http_ssl_alpn_select(ngx_ssl_conn_t 
> 
>     } else
> #endif
> +#if (NGX_HTTP_V2)
>     {
> -        srv = (unsigned char *) NGX_HTTP_ALPN_PROTOS;
> -        srvlen = sizeof(NGX_HTTP_ALPN_PROTOS) - 1;
> +        h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module);
> +
> +        if (h2scf->enable || hc->addr_conf->http2) {
> +            srv = (unsigned char *) NGX_HTTP_V2_ALPN_PROTO NGX_HTTP_ALPN_PROTOS;
> +            srvlen = sizeof(NGX_HTTP_V2_ALPN_PROTO NGX_HTTP_ALPN_PROTOS) - 1;
> +        }
>     }
> +#endif
> 
>     if (SSL_select_next_proto((unsigned char **) out, outlen, srv, srvlen,
>                               in, inlen)
> diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
> --- a/src/http/ngx_http_core_module.c
> +++ b/src/http/ngx_http_core_module.c
> @@ -4179,6 +4179,11 @@ ngx_http_core_listen(ngx_conf_t *cf, ngx
> 
>         if (ngx_strcmp(value[n].data, "http2") == 0) {
> #if (NGX_HTTP_V2)
> +            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
> +                               "the \"listen ... http2\" directive "
> +                               "is deprecated, use "
> +                               "the \"http2\" directive instead");
> +
>             lsopt.http2 = 1;
>             continue;
> #else
> diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
> --- a/src/http/ngx_http_request.c
> +++ b/src/http/ngx_http_request.c
> @@ -318,12 +318,6 @@ ngx_http_init_connection(ngx_connection_
>     rev->handler = ngx_http_wait_request_handler;
>     c->write->handler = ngx_http_empty_handler;
> 
> -#if (NGX_HTTP_V2)
> -    if (hc->addr_conf->http2) {
> -        rev->handler = ngx_http_v2_init;
> -    }
> -#endif
> -
> #if (NGX_HTTP_V3)
>     if (hc->addr_conf->quic) {
>         ngx_http_v3_init_stream(c);
> @@ -383,6 +377,9 @@ ngx_http_wait_request_handler(ngx_event_
>     ngx_buf_t                 *b;
>     ngx_connection_t          *c;
>     ngx_http_connection_t     *hc;
> +#if (NGX_HTTP_V2)
> +    ngx_http_v2_srv_conf_t    *h2scf;
> +#endif
>     ngx_http_core_srv_conf_t  *cscf;
> 
>     c = rev->data;
> @@ -429,6 +426,8 @@ ngx_http_wait_request_handler(ngx_event_
>         b->end = b->last + size;
>     }
> 
> +    size = b->end - b->last;
> +
>     n = c->recv(c, b->last, size);
> 
>     if (n == NGX_AGAIN) {
> @@ -443,12 +442,16 @@ ngx_http_wait_request_handler(ngx_event_
>             return;
>         }
> 
> -        /*
> -         * We are trying to not hold c->buffer's memory for an idle connection.
> -         */
> -
> -        if (ngx_pfree(c->pool, b->start) == NGX_OK) {
> -            b->start = NULL;
> +        if (b->pos == b->last) {
> +
> +            /*
> +             * We are trying to not hold c->buffer's memory for an
> +             * idle connection.
> +             */
> +
> +            if (ngx_pfree(c->pool, b->start) == NGX_OK) {
> +                b->start = NULL;
> +            }
>         }
> 
>         return;
> @@ -489,6 +492,30 @@ ngx_http_wait_request_handler(ngx_event_
>         }
>     }
> 
> +#if (NGX_HTTP_V2)
> +
> +    h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module);
> +
> +    if (!c->ssl && (h2scf->enable || hc->addr_conf->http2)) {
> +
> +        size = ngx_min(sizeof(NGX_HTTP_V2_PREFACE) - 1,
> +                       (size_t) (b->last - b->pos));
> +
> +        if (ngx_memcmp(b->pos, NGX_HTTP_V2_PREFACE, size) == 0) {
> +
> +            if (size == sizeof(NGX_HTTP_V2_PREFACE) - 1) {
> +                ngx_http_v2_init(rev);
> +                return;
> +            }
> +
> +            c->log->action = "waiting for request";
> +            ngx_post_event(rev, &ngx_posted_events);
> +            return;
> +        }
> +    }
> +
> +#endif
> +

There are two subtile changes:

- if we receive bad invalid connection preface,
now it is handled in the generic ngx_http_wait_request_handler(),
meaning HTTP/1.1 400 will be sent on error.
This is acceptable by RFC 9113, though:
: A GOAWAY frame (Section 6.8) MAY be omitted in this case, since
: an invalid preface indicates that the peer is not using HTTP/2.
But it probably deserves to write a not in the commit message

- the same is about bad PROXY protocol string

Looks like we can optimize parsing PROXY after ngx_http_v2_init(),
since PROXY is now always parsed in ngx_http_wait_request_handler().

>     c->log->action = "reading client request line";
> 
>     ngx_reusable_connection(c, 0);
> @@ -808,13 +835,16 @@ ngx_http_ssl_handshake_handler(ngx_conne
> #if (NGX_HTTP_V2                                                              \
>      && defined TLSEXT_TYPE_application_layer_protocol_negotiation)
>         {
> -        unsigned int            len;
> -        const unsigned char    *data;
> -        ngx_http_connection_t  *hc;
> +        unsigned int             len;
> +        const unsigned char     *data;
> +        ngx_http_connection_t   *hc;
> +        ngx_http_v2_srv_conf_t  *h2scf;
> 
>         hc = c->data;
> 
> -        if (hc->addr_conf->http2) {
> +        h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module);
> +
> +        if (h2scf->enable || hc->addr_conf->http2) {
> 
>             SSL_get0_alpn_selected(c->ssl->connection, &data, &len);
> 
> diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
> --- a/src/http/v2/ngx_http_v2.c
> +++ b/src/http/v2/ngx_http_v2.c
> @@ -232,6 +232,7 @@ static ngx_http_v2_parse_header_t  ngx_h
> void
> ngx_http_v2_init(ngx_event_t *rev)
> {
> +    u_char                    *p, *end;
>     ngx_connection_t          *c;
>     ngx_pool_cleanup_t        *cln;
>     ngx_http_connection_t     *hc;
> @@ -335,6 +336,29 @@ ngx_http_v2_init(ngx_event_t *rev)
>     c->idle = 1;
>     ngx_reusable_connection(c, 0);
> 
> +    if (c->buffer) {
> +        p = c->buffer->pos;
> +        end = c->buffer->last;
> +
> +        do {
> +            p = h2c->state.handler(h2c, p, end);
> +
> +            if (p == NULL) {
> +                return;
> +            }
> +
> +        } while (p != end);
> +
> +        h2c->total_bytes += p - c->buffer->pos;
> +        c->buffer->pos = p;
> +
> +        if (h2c->total_bytes / 8 > h2c->payload_bytes + 1048576) {
> +            ngx_log_error(NGX_LOG_INFO, c->log, 0, "http2 flood detected");
> +            ngx_http_v2_finalize_connection(h2c, NGX_HTTP_V2_NO_ERROR);
> +            return;
> +        }
> +    }
> +
>     ngx_http_v2_read_handler(rev);
> }
> 
> @@ -871,7 +895,7 @@ static u_char *
> ngx_http_v2_state_preface(ngx_http_v2_connection_t *h2c, u_char *pos,
>     u_char *end)
> {
> -    static const u_char preface[] = "PRI * HTTP/2.0\r\n";
> +    static const u_char preface[] = NGX_HTTP_V2_PREFACE_START;
> 
>     if ((size_t) (end - pos) < sizeof(preface) - 1) {
>         return ngx_http_v2_state_save(h2c, pos, end, ngx_http_v2_state_preface);
> @@ -892,7 +916,7 @@ static u_char *
> ngx_http_v2_state_preface_end(ngx_http_v2_connection_t *h2c, u_char *pos,
>     u_char *end)
> {
> -    static const u_char preface[] = "\r\nSM\r\n\r\n";
> +    static const u_char preface[] = NGX_HTTP_V2_PREFACE_END;
> 
>     if ((size_t) (end - pos) < sizeof(preface) - 1) {
>         return ngx_http_v2_state_save(h2c, pos, end,
> @@ -3946,10 +3970,22 @@ static void
> ngx_http_v2_run_request(ngx_http_request_t *r)
> {
>     ngx_connection_t          *fc;
> +    ngx_http_v3_srv_conf_t    *h2scf;

ngx_http_v2_srv_conf_t

>     ngx_http_v2_connection_t  *h2c;
> 
>     fc = r->connection;
> 
> +    h2scf = ngx_http_get_module_srv_conf(r, ngx_http_v2_module);
> +
> +    if (!h2scf->enable && !r->http_connection->addr_conf->http2) {
> +        ngx_log_error(NGX_LOG_INFO, fc->log, 0,
> +                      "client attempted to request the server name "
> +                      "for which the negotitated protocol is unavailable");

- typo: negotiated
(same as in 1st patch)

> +
> +        ngx_http_finalize_request(r, NGX_HTTP_MISDIRECTED_REQUEST);
> +        goto failed;
> +    }
> +
>     if (ngx_http_v2_construct_request_line(r) != NGX_OK) {
>         goto failed;
>     }
> diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h
> --- a/src/http/v2/ngx_http_v2.h
> +++ b/src/http/v2/ngx_http_v2.h
> @@ -64,6 +64,16 @@ typedef u_char *(*ngx_http_v2_handler_pt
> 
> 
> typedef struct {
> +    ngx_flag_t                       enable;
> +    size_t                           pool_size;
> +    ngx_uint_t                       concurrent_streams;
> +    ngx_uint_t                       concurrent_pushes;
> +    size_t                           preread_size;
> +    ngx_uint_t                       streams_index_mask;
> +} ngx_http_v2_srv_conf_t;
> +
> +
> +typedef struct {
>     ngx_str_t                        name;
>     ngx_str_t                        value;
> } ngx_http_v2_header_t;
> @@ -408,9 +418,17 @@ ngx_int_t ngx_http_v2_table_size(ngx_htt
> #define NGX_HTTP_V2_USER_AGENT_INDEX      58
> #define NGX_HTTP_V2_VARY_INDEX            59
> 
> +#define NGX_HTTP_V2_PREFACE_START         "PRI * HTTP/2.0\r\n"
> +#define NGX_HTTP_V2_PREFACE_END           "\r\nSM\r\n\r\n"
> +#define NGX_HTTP_V2_PREFACE               NGX_HTTP_V2_PREFACE_START           \
> +                                          NGX_HTTP_V2_PREFACE_END
> +
> 
> u_char *ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len,
>     u_char *tmp, ngx_uint_t lower);
> 
> 
> +extern ngx_module_t  ngx_http_v2_module;
> +
> +
> #endif /* _NGX_HTTP_V2_H_INCLUDED_ */
> diff --git a/src/http/v2/ngx_http_v2_module.c b/src/http/v2/ngx_http_v2_module.c
> --- a/src/http/v2/ngx_http_v2_module.c
> +++ b/src/http/v2/ngx_http_v2_module.c
> @@ -75,6 +75,13 @@ static ngx_conf_post_t  ngx_http_v2_chun
> 
> static ngx_command_t  ngx_http_v2_commands[] = {
> 
> +    { ngx_string("http2"),
> +      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
> +      ngx_conf_set_flag_slot,
> +      NGX_HTTP_SRV_CONF_OFFSET,
> +      offsetof(ngx_http_v2_srv_conf_t, enable),
> +      NULL },
> +
>     { ngx_string("http2_recv_buffer_size"),
>       NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
>       ngx_conf_set_size_slot,
> @@ -314,6 +321,8 @@ ngx_http_v2_create_srv_conf(ngx_conf_t *
>         return NULL;
>     }
> 
> +    h2scf->enable = NGX_CONF_UNSET;
> +
>     h2scf->pool_size = NGX_CONF_UNSET_SIZE;
> 
>     h2scf->concurrent_streams = NGX_CONF_UNSET_UINT;
> @@ -333,6 +342,8 @@ ngx_http_v2_merge_srv_conf(ngx_conf_t *c
>     ngx_http_v2_srv_conf_t *prev = parent;
>     ngx_http_v2_srv_conf_t *conf = child;
> 
> +    ngx_conf_merge_value(conf->enable, prev->enable, 0);
> +
>     ngx_conf_merge_size_value(conf->pool_size, prev->pool_size, 4096);
> 
>     ngx_conf_merge_uint_value(conf->concurrent_streams,
> diff --git a/src/http/v2/ngx_http_v2_module.h b/src/http/v2/ngx_http_v2_module.h
> --- a/src/http/v2/ngx_http_v2_module.h
> +++ b/src/http/v2/ngx_http_v2_module.h
> @@ -21,15 +21,6 @@ typedef struct {
> 
> 
> typedef struct {
> -    size_t                          pool_size;
> -    ngx_uint_t                      concurrent_streams;
> -    ngx_uint_t                      concurrent_pushes;
> -    size_t                          preread_size;
> -    ngx_uint_t                      streams_index_mask;
> -} ngx_http_v2_srv_conf_t;
> -
> -
> -typedef struct {
>     size_t                          chunk_size;
> 
>     ngx_flag_t                      push_preload;
> @@ -39,7 +30,4 @@ typedef struct {
> } ngx_http_v2_loc_conf_t;
> 
> 
> -extern ngx_module_t  ngx_http_v2_module;
> -
> -
> #endif /* _NGX_HTTP_V2_MODULE_H_INCLUDED_ */

(BTW, we could make a separate ngx_http_v3_module.h as well,
to keep there a private stuff.)

-- 
Sergey Kandaurov


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