QUIC: removed "quic_mtu" directive.

The directive used to set the value of the "max_udp_payload_size" transport
parameter.  According to RFC 9000, Section 18.2, the value specifies the size
of buffer for reading incoming datagrams:

    This limit does act as an additional constraint on datagram size in
    the same way as the path MTU, but it is a property of the endpoint
    and not the path; see Section 14. It is expected that this is the
    space an endpoint dedicates to holding incoming packets.

Current QUIC implementation uses the maximum possible buffer size (65527) for
reading datagrams.

5 files changed, 1 insertions, 85 deletions

diff --git a/README b/README
index 7470457c3..cde316a7d 100644
--- a/README
+++ b/README
@@ -123,10 +123,6 @@ Experimental QUIC support for nginx
 
         quic_gso on;
 
-    To limit maximum UDP payload size on receive path:
-
-        quic_mtu <size>;
-
     To set host key for various tokens:
 
         quic_host_key <filename>;
@@ -209,14 +205,6 @@ Example configuration:
     Optimized sending is only supported on Linux featuring UDP_SEGMENT.
 
 
-    Syntax: quic_mtu size;
-    Default: quic_mtu 65527;
-    Context: http | stream, server
-
-    Sets the QUIC max_udp_payload_size transport parameter value.
-    This is the maximum UDP payload that we are willing to receive.
-
-
     Syntax: quic_host_key file;
     Default: -
     Context: http | stream, server
diff --git a/src/event/quic/ngx_event_quic.h b/src/event/quic/ngx_event_quic.h
index 56713ec4d..0c68d68f0 100644
--- a/src/event/quic/ngx_event_quic.h
+++ b/src/event/quic/ngx_event_quic.h
@@ -69,7 +69,6 @@ typedef struct {
     ngx_flag_t                     disable_active_migration;
     ngx_msec_t                     timeout;
     ngx_str_t                      host_key;
-    size_t                         mtu;
     size_t                         stream_buffer_size;
     ngx_uint_t                     max_concurrent_streams_bidi;
     ngx_uint_t                     max_concurrent_streams_uni;
diff --git a/src/event/quic/ngx_event_quic_transport.c b/src/event/quic/ngx_event_quic_transport.c
index 46456db1d..b663efbe1 100644
--- a/src/event/quic/ngx_event_quic_transport.c
+++ b/src/event/quic/ngx_event_quic_transport.c
@@ -1987,7 +1987,7 @@ ngx_quic_init_transport_params(ngx_quic_tp_t *tp, ngx_quic_conf_t *qcf)
 
     tp->max_idle_timeout = qcf->timeout;
 
-    tp->max_udp_payload_size = qcf->mtu;
+    tp->max_udp_payload_size = NGX_QUIC_MAX_UDP_PAYLOAD_SIZE;
 
     nstreams = qcf->max_concurrent_streams_bidi
                + qcf->max_concurrent_streams_uni;
diff --git a/src/http/v3/ngx_http_v3_module.c b/src/http/v3/ngx_http_v3_module.c
index 02b88b479..8569f07a0 100644
--- a/src/http/v3/ngx_http_v3_module.c
+++ b/src/http/v3/ngx_http_v3_module.c
@@ -16,8 +16,6 @@ static ngx_int_t ngx_http_v3_add_variables(ngx_conf_t *cf);
 static void *ngx_http_v3_create_srv_conf(ngx_conf_t *cf);
 static char *ngx_http_v3_merge_srv_conf(ngx_conf_t *cf, void *parent,
     void *child);
-static char *ngx_http_quic_mtu(ngx_conf_t *cf, void *post,
-    void *data);
 static char *ngx_http_quic_host_key(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
 static void *ngx_http_v3_create_loc_conf(ngx_conf_t *cf);
@@ -26,10 +24,6 @@ static char *ngx_http_v3_merge_loc_conf(ngx_conf_t *cf, void *parent,
 static char *ngx_http_v3_push(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
 
 
-static ngx_conf_post_t  ngx_http_quic_mtu_post =
-    { ngx_http_quic_mtu };
-
-
 static ngx_command_t  ngx_http_v3_commands[] = {
 
     { ngx_string("http3"),
@@ -95,13 +89,6 @@ static ngx_command_t  ngx_http_v3_commands[] = {
       offsetof(ngx_http_v3_srv_conf_t, quic.gso_enabled),
       NULL },
 
-    { ngx_string("quic_mtu"),
-      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
-      ngx_conf_set_size_slot,
-      NGX_HTTP_SRV_CONF_OFFSET,
-      offsetof(ngx_http_v3_srv_conf_t, quic.mtu),
-      &ngx_http_quic_mtu_post },
-
     { ngx_string("quic_host_key"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
       ngx_http_quic_host_key,
@@ -240,7 +227,6 @@ ngx_http_v3_create_srv_conf(ngx_conf_t *cf)
     h3scf->max_concurrent_pushes = NGX_CONF_UNSET_UINT;
     h3scf->max_concurrent_streams = NGX_CONF_UNSET_UINT;
 
-    h3scf->quic.mtu = NGX_CONF_UNSET_SIZE;
     h3scf->quic.stream_buffer_size = NGX_CONF_UNSET_SIZE;
     h3scf->quic.max_concurrent_streams_bidi = NGX_CONF_UNSET_UINT;
     h3scf->quic.max_concurrent_streams_uni = NGX_HTTP_V3_MAX_UNI_STREAMS;
@@ -277,9 +263,6 @@ ngx_http_v3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
 
     conf->max_blocked_streams = conf->max_concurrent_streams;
 
-    ngx_conf_merge_size_value(conf->quic.mtu, prev->quic.mtu,
-                              NGX_QUIC_MAX_UDP_PAYLOAD_SIZE);
-
     ngx_conf_merge_size_value(conf->quic.stream_buffer_size,
                               prev->quic.stream_buffer_size,
                               65536);
@@ -335,26 +318,6 @@ ngx_http_v3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
 
 
 static char *
-ngx_http_quic_mtu(ngx_conf_t *cf, void *post, void *data)
-{
-    size_t *sp = data;
-
-    if (*sp < NGX_QUIC_MIN_INITIAL_SIZE
-        || *sp > NGX_QUIC_MAX_UDP_PAYLOAD_SIZE)
-    {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                           "\"quic_mtu\" must be between %d and %d",
-                           NGX_QUIC_MIN_INITIAL_SIZE,
-                           NGX_QUIC_MAX_UDP_PAYLOAD_SIZE);
-
-        return NGX_CONF_ERROR;
-    }
-
-    return NGX_CONF_OK;
-}
-
-
-static char *
 ngx_http_quic_host_key(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
     ngx_http_v3_srv_conf_t  *h3scf = conf;
diff --git a/src/stream/ngx_stream_quic_module.c b/src/stream/ngx_stream_quic_module.c
index 644fa0380..42f5fe060 100644
--- a/src/stream/ngx_stream_quic_module.c
+++ b/src/stream/ngx_stream_quic_module.c
@@ -16,12 +16,9 @@ static ngx_int_t ngx_stream_quic_add_variables(ngx_conf_t *cf);
 static void *ngx_stream_quic_create_srv_conf(ngx_conf_t *cf);
 static char *ngx_stream_quic_merge_srv_conf(ngx_conf_t *cf, void *parent,
     void *child);
-static char *ngx_stream_quic_mtu(ngx_conf_t *cf, void *post, void *data);
 static char *ngx_stream_quic_host_key(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
 
-static ngx_conf_post_t  ngx_stream_quic_mtu_post =
-    { ngx_stream_quic_mtu };
 
 static ngx_command_t  ngx_stream_quic_commands[] = {
 
@@ -32,13 +29,6 @@ static ngx_command_t  ngx_stream_quic_commands[] = {
       offsetof(ngx_quic_conf_t, timeout),
       NULL },
 
-    { ngx_string("quic_mtu"),
-      NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
-      ngx_conf_set_size_slot,
-      NGX_STREAM_SRV_CONF_OFFSET,
-      offsetof(ngx_quic_conf_t, mtu),
-      &ngx_stream_quic_mtu_post },
-
     { ngx_string("quic_stream_buffer_size"),
       NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_size_slot,
@@ -175,7 +165,6 @@ ngx_stream_quic_create_srv_conf(ngx_conf_t *cf)
      */
 
     conf->timeout = NGX_CONF_UNSET_MSEC;
-    conf->mtu = NGX_CONF_UNSET_SIZE;
     conf->stream_buffer_size = NGX_CONF_UNSET_SIZE;
     conf->max_concurrent_streams_bidi = NGX_CONF_UNSET_UINT;
     conf->max_concurrent_streams_uni = NGX_CONF_UNSET_UINT;
@@ -199,9 +188,6 @@ ngx_stream_quic_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
 
     ngx_conf_merge_msec_value(conf->timeout, prev->timeout, 60000);
 
-    ngx_conf_merge_size_value(conf->mtu, prev->mtu,
-                              NGX_QUIC_MAX_UDP_PAYLOAD_SIZE);
-
     ngx_conf_merge_size_value(conf->stream_buffer_size,
                               prev->stream_buffer_size,
                               65536);
@@ -260,26 +246,6 @@ ngx_stream_quic_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
 
 
 static char *
-ngx_stream_quic_mtu(ngx_conf_t *cf, void *post, void *data)
-{
-    size_t *sp = data;
-
-    if (*sp < NGX_QUIC_MIN_INITIAL_SIZE
-        || *sp > NGX_QUIC_MAX_UDP_PAYLOAD_SIZE)
-    {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                           "\"quic_mtu\" must be between %d and %d",
-                           NGX_QUIC_MIN_INITIAL_SIZE,
-                           NGX_QUIC_MAX_UDP_PAYLOAD_SIZE);
-
-        return NGX_CONF_ERROR;
-    }
-
-    return NGX_CONF_OK;
-}
-
-
-static char *
 ngx_stream_quic_host_key(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
     ngx_quic_conf_t  *qcf = conf;