BUG/MINOR: haproxy: Fix option to disable the fast-forward

The option was renamed to only permit to disable the fast-forward. First
there is no reason to enable it because it is the default behavior. Then it
introduced a bug because there is no way to be sure the command line has
precedence over the configuration this way. So, the option is now named
"tune.disable-fast-forward" and does not support any argument. And of
course, the commande line option "-dF" has now precedence over the
configuration.

No backport needed.

doc/configuration.txt

@@ -1123,7 +1123,7 @@ The following keywords are supported in the "global" section :
    - tune.buffers.reserve
    - tune.bufsize
    - tune.comp.maxlevel
-   - tune.fast-forward
+   - tune.disable-fast-forward
    - tune.fd.edge-triggered
    - tune.h2.header-table-size
    - tune.h2.initial-window-size
@@ -2832,23 +2832,22 @@ tune.comp.maxlevel <number>
   Each session using compression initializes the compression algorithm with
   this value. The default value is 1.
 
+tune.disable-fast-forward [ EXPERIMENTAL ]
+  Disables the data fast-forwarding. It is a mechanism to optimize the data
+  forwarding by passing data directly from a side to the other one without
+  waking the stream up. Thanks to this directive, it is possible to disable
+  this optimization. Note it also disable any kernel tcp splicing. This command
+  is not meant for regular use, it will generally only be suggested by
+  developers along complex debugging sessions. For this reason it is internally
+  marked as experimental, meaning that "expose-experimental-directives" must
+  appear on a line before this directive.
+
 tune.fail-alloc
   If compiled with DEBUG_FAIL_ALLOC or started with "-dMfail", gives the
   percentage of chances an allocation attempt fails. Must be between 0 (no
   failure) and 100 (no success). This is useful to debug and make sure memory
   failures are handled gracefully.
 
-tune.fast-forward { on | off } [ EXPERIMENTAL ]
-
-  Enabled ('on') or disables ('off') the data fast-forwarding. It is a
-  mechanism to optimize the data forwarding by passing data directly from a
-  side to the other one without waking the stream up. Thanks to this directive,
-  it is possible to disable this optimization. Note it also disable any kernel
-  tcp splicing. This command is not meant for regular use, it will generally
-  only be suggested by developers along complex debugging sessions. For this
-  reason it is internally marked as experimental, meaning that
-  "expose-experimental-directives" must appear on a line before this directive.
-
 tune.fd.edge-triggered { on | off }  [ EXPERIMENTAL ]
   Enables ('on') or disables ('off') the edge-triggered polling mode for FDs
   that support it. This is currently only support with epoll. It may noticeably

include/haproxy/global-t.h

@@ -80,7 +80,7 @@
 #define GTUNE_QUICK_EXIT         (1<<23)
 #define GTUNE_QUIC_SOCK_PER_CONN (1<<24)
 #define GTUNE_NO_QUIC            (1<<25)
-#define GTUNE_NO_FAST_FWD        (1<<26)
+#define GTUNE_USE_FAST_FWD       (1<<26)
 
 /* SSL server verify mode */
 enum {

src/cfgparse-global.c

@@ -493,7 +493,7 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 			goto out;
 		}
 	}
-	else if (strcmp(args[0], "tune.fast-forward") == 0) {
+	else if (strcmp(args[0], "tune.disable-fast-forward") == 0) {
 		if (!experimental_directives_allowed) {
 			ha_alert("parsing [%s:%d] : '%s' directive is experimental, must be allowed via a global 'expose-experimental-directives'",
 				 file, linenum, args[0]);
@@ -502,24 +502,9 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		}
 		mark_tainted(TAINTED_CONFIG_EXP_KW_DECLARED);
 
-		if (alertif_too_many_args(1, file, linenum, args, &err_code))
+		if (alertif_too_many_args(0, file, linenum, args, &err_code))
 			goto out;
-		if (*(args[1]) == 0) {
+		global.tune.options &= GTUNE_USE_FAST_FWD;
-			ha_alert("parsing [%s:%d] : '%s' expects either 'on' or 'off' as argument.",
-				 file, linenum, args[0]);
-			err_code |= ERR_ALERT | ERR_FATAL;
-			goto out;
-		}
-		if (strcmp(args[1], "on") == 0)
-			global.tune.options &= ~GTUNE_NO_FAST_FWD;
-		else if (strcmp(args[1], "off") == 0)
-			global.tune.options |= GTUNE_NO_FAST_FWD;
-		else {
-			ha_alert("parsing [%s:%d] : '%s' expects either 'on' or 'off' but got '%s'.",
-				 file, linenum, args[0], args[1]);
-			err_code |= ERR_ALERT | ERR_FATAL;
-			goto out;
-		}
 	}
 	else if (strcmp(args[0], "cluster-secret") == 0) {
 		if (alertif_too_many_args(1, file, linenum, args, &err_code))

src/haproxy.c

@@ -1598,6 +1598,8 @@ static void init_args(int argc, char **argv)
 #endif
 	global.tune.options |= GTUNE_STRICT_LIMITS;
 
+	global.tune.options |= GTUNE_USE_FAST_FWD; /* Use fast-forward by default */
+
 	/* keep a copy of original arguments for the master process */
 	old_argv = copy_argv(argc, argv);
 	if (!old_argv) {
@@ -1649,7 +1651,7 @@ static void init_args(int argc, char **argv)
 				global.tune.options &= ~GTUNE_USE_REUSEPORT;
 #endif
 			else if (*flag == 'd' && flag[1] == 'F')
-				global.tune.options |= GTUNE_NO_FAST_FWD;
+				global.tune.options &= ~GTUNE_USE_FAST_FWD;
 			else if (*flag == 'd' && flag[1] == 'V')
 				global.ssl_server_verify = SSL_SERVER_VERIFY_NONE;
 			else if (*flag == 'V')

src/http_ana.c

@@ -941,7 +941,7 @@ int http_request_forward_body(struct stream *s, struct channel *req, int an_bit)
 	}
 	else {
 		c_adv(req, htx->data - co_data(req));
-		if (!(global.tune.options & GTUNE_NO_FAST_FWD) && (msg->flags & HTTP_MSGF_XFER_LEN))
+		if ((global.tune.options & GTUNE_USE_FAST_FWD) && (msg->flags & HTTP_MSGF_XFER_LEN))
 			channel_htx_forward_forever(req, htx);
 	}
 
@@ -2044,7 +2044,7 @@ int http_response_forward_body(struct stream *s, struct channel *res, int an_bit
 	}
 	else {
 		c_adv(res, htx->data - co_data(res));
-		if (!(global.tune.options & GTUNE_NO_FAST_FWD) && (msg->flags & HTTP_MSGF_XFER_LEN))
+		if ((global.tune.options & GTUNE_USE_FAST_FWD) && (msg->flags & HTTP_MSGF_XFER_LEN))
 			channel_htx_forward_forever(res, htx);
 	}
 

src/stream.c

@@ -2258,7 +2258,7 @@ struct task *process_stream(struct task *t, void *context, unsigned int state)
 			 * to the consumer.
 			 */
 			co_set_data(req, htx->data);
-			if (!(global.tune.options & GTUNE_NO_FAST_FWD) && !(req->flags & (CF_SHUTR|CF_SHUTW_NOW)))
+			if ((global.tune.options & GTUNE_USE_FAST_FWD) && !(req->flags & (CF_SHUTR|CF_SHUTW_NOW)))
 				channel_htx_forward_forever(req, htx);
 		}
 		else {
@@ -2266,7 +2266,7 @@ struct task *process_stream(struct task *t, void *context, unsigned int state)
 			 * to the consumer (which might possibly not be connected yet).
 			 */
 			c_adv(req, ci_data(req));
-			if (!(global.tune.options & GTUNE_NO_FAST_FWD) && !(req->flags & (CF_SHUTR|CF_SHUTW_NOW)))
+			if ((global.tune.options & GTUNE_USE_FAST_FWD) && !(req->flags & (CF_SHUTR|CF_SHUTW_NOW)))
 				channel_forward_forever(req);
 		}
 	}
@@ -2429,7 +2429,7 @@ struct task *process_stream(struct task *t, void *context, unsigned int state)
 			 * to the consumer.
 			 */
 			co_set_data(res, htx->data);
-			if (!(global.tune.options & GTUNE_NO_FAST_FWD) && !(res->flags & (CF_SHUTR|CF_SHUTW_NOW)))
+			if ((global.tune.options & GTUNE_USE_FAST_FWD) && !(res->flags & (CF_SHUTR|CF_SHUTW_NOW)))
 				channel_htx_forward_forever(res, htx);
 		}
 		else {
@@ -2437,7 +2437,7 @@ struct task *process_stream(struct task *t, void *context, unsigned int state)
 			 * to the consumer.
 			 */
 			c_adv(res, ci_data(res));
-			if (!(global.tune.options & GTUNE_NO_FAST_FWD) && !(res->flags & (CF_SHUTR|CF_SHUTW_NOW)))
+			if ((global.tune.options & GTUNE_USE_FAST_FWD) && !(res->flags & (CF_SHUTR|CF_SHUTW_NOW)))
 				channel_forward_forever(res);
 		}