SSL: SSL_sendfile() support with kernel TLS.

Requires OpenSSL 3.0 compiled with "enable-ktls" option.  Further, KTLS
needs to be enabled in kernel, and in OpenSSL, either via OpenSSL
configuration file or with "ssl_conf_command Options KTLS;" in nginx
configuration.

On FreeBSD, kernel TLS is available starting with FreeBSD 13.0, and
can be enabled with "sysctl kern.ipc.tls.enable=1" and "kldload ktls_ocf"
to load a software backend, see man ktls(4) for details.

On Linux, kernel TLS is available starting with kernel 4.13 (at least 5.2
is recommended), and needs kernel compiled with CONFIG_TLS=y (with
CONFIG_TLS=m, which is used at least on Ubuntu 21.04 by default,
the tls module needs to be loaded with "modprobe tls").

2 files changed, 6 insertions, 4 deletions

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index 76bbcd67c..013b7158e 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -607,7 +607,7 @@ ngx_http_alloc_request(ngx_connection_t *c)
     }
 
 #if (NGX_HTTP_SSL)
-    if (c->ssl) {
+    if (c->ssl && !c->ssl->sendfile) {
         r->main_filter_need_in_memory = 1;
     }
 #endif
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 01c7877e6..daa8d2201 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -1683,9 +1683,6 @@ ngx_http_upstream_ssl_init_connection(ngx_http_request_t *r,
         return;
     }
 
-    c->sendfile = 0;
-    u->output.sendfile = 0;
-
     if (u->conf->ssl_server_name || u->conf->ssl_verify) {
         if (ngx_http_upstream_ssl_name(r, u, c) != NGX_OK) {
             ngx_http_upstream_finalize_request(r, u,
@@ -1791,6 +1788,11 @@ ngx_http_upstream_ssl_handshake(ngx_http_request_t *r, ngx_http_upstream_t *u,
             }
         }
 
+        if (!c->ssl->sendfile) {
+            c->sendfile = 0;
+            u->output.sendfile = 0;
+        }
+
         c->write->handler = ngx_http_upstream_handler;
         c->read->handler = ngx_http_upstream_handler;