commit c344e21f23c6605caa257abbf46fd333b7015928

Author: Tomas Korbar <tkorbar@redhat.com>

Date:   Wed Oct 18 20:42:21 2023 +0200

    vcl_vrt: Skip VCL execution if the client is gone

    Upstream PR #4006

diff --git a/bin/varnishd/VSC_main.vsc b/bin/varnishd/VSC_main.vsc

index b237f86..88a659f 100644

--- a/bin/varnishd/VSC_main.vsc

+++ b/bin/varnishd/VSC_main.vsc

@@ -324,6 +324,15 @@

 	Number of times an HTTP/2 stream was refused because the queue was

 	too long already. See also parameter thread_queue_limit.

+.. varnish_vsc:: req_reset

+	:group: wrk

+	:oneliner:	Requests reset

+

+	Number of times a client left before the VCL processing of its

+	requests completed. For HTTP/2 sessions, either the stream was

+	reset by an RST_STREAM frame from the client, or a stream or

+	connection error occurred.

+

 .. varnish_vsc:: n_object

 	:type:	gauge

 	:group: wrk

diff --git a/bin/varnishd/cache/cache_transport.h b/bin/varnishd/cache/cache_transport.h

index 5da5e35..8546411 100644

--- a/bin/varnishd/cache/cache_transport.h

+++ b/bin/varnishd/cache/cache_transport.h

@@ -42,6 +42,7 @@ typedef void vtr_sess_panic_f (struct vsb *, const struct sess *);

 typedef void vtr_req_panic_f (struct vsb *, const struct req *);

 typedef void vtr_req_fail_f (struct req *, enum sess_close);

 typedef void vtr_reembark_f (struct worker *, struct req *);

+typedef int vtr_poll_f (struct req *);

 typedef int vtr_minimal_response_f (struct req *, uint16_t status);

 struct transport {

@@ -62,6 +63,7 @@ struct transport {

 	vtr_sess_panic_f		*sess_panic;

 	vtr_req_panic_f			*req_panic;

 	vtr_reembark_f			*reembark;

+	vtr_poll_f			*poll;

 	vtr_minimal_response_f		*minimal_response;

 	VTAILQ_ENTRY(transport)		list;

diff --git a/bin/varnishd/cache/cache_vcl_vrt.c b/bin/varnishd/cache/cache_vcl_vrt.c

index 5f3bfee..e35ae59 100644

--- a/bin/varnishd/cache/cache_vcl_vrt.c

+++ b/bin/varnishd/cache/cache_vcl_vrt.c

@@ -37,8 +37,10 @@

 #include "cache_varnishd.h"

 #include "vcl.h"

+#include "vtim.h"

 #include "cache_director.h"

+#include "cache_transport.h"

 #include "cache_vcl.h"

 /*--------------------------------------------------------------------*/

@@ -338,6 +340,35 @@ VRT_rel_vcl(VRT_CTX, struct vclref **refp)

  * The workspace argument is where random VCL stuff gets space from.

  */

+static int

+req_poll(struct worker *wrk, struct req *req)

+{

+

+	CHECK_OBJ_NOTNULL(req->top, REQ_MAGIC);

+	CHECK_OBJ_NOTNULL(req->top->transport, TRANSPORT_MAGIC);

+

+	/* NB: Since a fail transition leads to vcl_synth, the request may be

+	 * short-circuited twice.

+	 */

+	if (req->req_reset) {

+		wrk->handling = VCL_RET_FAIL;

+		return (-1);

+	}

+

+	if (!FEATURE(FEATURE_VCL_REQ_RESET))

+		return (0);

+	if (req->top->transport->poll == NULL)

+		return (0);

+	if (req->top->transport->poll(req->top) >= 0)

+		return (0);

+

+	VSLb_ts_req(req, "Reset", W_TIM_real(wrk));

+	wrk->stats->req_reset++;

+	wrk->handling = VCL_RET_FAIL;

+	req->req_reset = 1;

+	return (-1);

+}

+

 static void

 vcl_call_method(struct worker *wrk, struct req *req, struct busyobj *bo,

     void *specific, unsigned method, vcl_func_f *func)

@@ -351,6 +382,8 @@ vcl_call_method(struct worker *wrk, struct req *req, struct busyobj *bo,

 		CHECK_OBJ_NOTNULL(req, REQ_MAGIC);

 		CHECK_OBJ_NOTNULL(req->sp, SESS_MAGIC);

 		CHECK_OBJ_NOTNULL(req->vcl, VCL_MAGIC);

+		if (req_poll(wrk, req))

+			return;

 		VCL_Req2Ctx(&ctx, req);

 	}

 	if (bo != NULL) {

diff --git a/bin/varnishd/http2/cache_http2_session.c b/bin/varnishd/http2/cache_http2_session.c

index 720b009..1584740 100644

--- a/bin/varnishd/http2/cache_http2_session.c

+++ b/bin/varnishd/http2/cache_http2_session.c

@@ -440,6 +440,16 @@ h2_new_session(struct worker *wrk, void *arg)

 	h2_del_sess(wrk, h2, SC_RX_JUNK);

 }

+static int v_matchproto_(vtr_poll_f)

+h2_poll(struct req *req)

+{

+	struct h2_req *r2;

+

+	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);

+	CAST_OBJ_NOTNULL(r2, req->transport_priv, H2_REQ_MAGIC);

+	return (r2->error ? -1 : 1);

+}

+

 struct transport H2_transport = {

 	.name =			"H2",

 	.magic =		TRANSPORT_MAGIC,

@@ -449,4 +459,5 @@ struct transport H2_transport = {

 	.req_body =		h2_req_body,

 	.req_fail =		h2_req_fail,

 	.sess_panic =		h2_sess_panic,

+	.poll =			h2_poll,

 };

diff --git a/bin/varnishd/mgt/mgt_param_bits.c b/bin/varnishd/mgt/mgt_param_bits.c

index 263d8a3..788d8f0 100644

--- a/bin/varnishd/mgt/mgt_param_bits.c

+++ b/bin/varnishd/mgt/mgt_param_bits.c

@@ -219,7 +219,12 @@ tweak_feature(struct vsb *vsb, const struct parspec *par, const char *arg)

 	(void)par;

 	if (arg != NULL && arg != JSON_FMT) {

-		if (!strcmp(arg, "none")) {

+		if (!strcmp(arg, "default")) {

+			AZ(bit_tweak(vsb, mgt_param.feature_bits,

+				FEATURE_Reserved,

+				"+vcl_req_reset",

+				feature_tags, "feature bit", "+"));

+		}else if (!strcmp(arg, "none")) {

 			memset(mgt_param.feature_bits,

 			    0, sizeof mgt_param.feature_bits);

 		} else {

@@ -271,6 +276,6 @@ struct parspec VSL_parspec[] = {

 #define FEATURE_BIT(U, l, d, ld) "\n\t" #l "\t" d

 #include "tbl/feature_bits.h"

 #undef FEATURE_BIT

-		, 0, "none", "" },

+		, 0, "default", "" },

 	{ NULL, NULL, NULL }

 };

diff --git a/doc/sphinx/reference/vsl.rst b/doc/sphinx/reference/vsl.rst

index 4d01f5b..b529562 100644

--- a/doc/sphinx/reference/vsl.rst

+++ b/doc/sphinx/reference/vsl.rst

@@ -71,6 +71,11 @@ Resp

 Restart

 	Client request is being restarted.

+Reset

+        The client closed its connection, reset its stream or caused

+        a stream error that forced Varnish to reset the stream. Request

+        processing is interrupted and considered failed.

+

 Pipe handling timestamps

 ~~~~~~~~~~~~~~~~~~~~~~~~

diff --git a/include/tbl/feature_bits.h b/include/tbl/feature_bits.h

index 23f1b01..844ecfa 100644

--- a/include/tbl/feature_bits.h

+++ b/include/tbl/feature_bits.h

@@ -83,6 +83,12 @@ FEATURE_BIT(HTTP_DATE_POSTEL,	http_date_postel,

     "like Date:, Last-Modified:, Expires: etc."

 )

+FEATURE_BIT(VCL_REQ_RESET,			vcl_req_reset,

+    "Stop processing client VCL once the client is gone.",

+    "Stop processing client VCL once the client is gone. "

+    "When this happens MAIN.req_reset is incremented."

+)

+

 #undef FEATURE_BIT

 /*lint -restore */

diff --git a/include/tbl/req_flags.h b/include/tbl/req_flags.h

index 2c0dbe8..3d3f05f 100644

--- a/include/tbl/req_flags.h

+++ b/include/tbl/req_flags.h

@@ -39,6 +39,7 @@ REQ_FLAG(is_hitpass,		1, 0, "")

 REQ_FLAG(waitinglist,		0, 0, "")

 REQ_FLAG(want100cont,		0, 0, "")

 REQ_FLAG(late100cont,		0, 0, "")

+REQ_FLAG(req_reset,		0, 0, "")

 #undef REQ_FLAG

 /*lint -restore */