MEDIUM: listener: store the default target per listener

This will be useful later to state that some listeners have to use
certain decoders (typically an HTTP/2 decoder) regardless of the
regular processing applied to other listeners. For now it simply
defaults to the frontend's default target, and it is used by the
session.

include/types/listener.h

@@ -173,6 +173,7 @@ struct listener {
 	int (*accept)(struct listener *l, int fd, struct sockaddr_storage *addr); /* upper layer's accept() */
 	struct task * (*handler)(struct task *t); /* protocol handler. It is a task */
 	struct proxy *frontend;		/* the frontend this listener belongs to, or NULL */
+	enum obj_type *default_target;  /* default target to use for accepted sessions or NULL */
 	struct list wait_queue;		/* link element to make the listener wait for something (LI_LIMITED)  */
 	unsigned int analysers;		/* bitmap of required protocol analysers */
 	int maxseg;			/* for TCP, advertised MSS */

src/cfgparse.c

@@ -1887,6 +1887,7 @@ int cfg_parse_peers(const char *file, int linenum, char **args, int kwm)
 					l->accept = session_accept;
 					l->handler = process_session;
 					l->analysers |=  ((struct proxy *)curpeers->peers_fe)->fe_req_ana;
+					l->default_target = ((struct proxy *)curpeers->peers_fe)->default_target;
 					l->options |= LI_O_UNLIMITED; /* don't make the peers subject to global limits */
 					global.maxsock += l->maxconn;
 				}
@@ -7710,6 +7711,7 @@ int check_config_validity()
 			listener->accept = session_accept;
 			listener->handler = process_session;
 			listener->analysers |= curproxy->fe_req_ana;
+			listener->default_target = curproxy->default_target;
 
 			if (!LIST_ISEMPTY(&curproxy->tcp_req.l4_rules))
 				listener->options |= LI_O_TCP_RULES;

src/dumpstats.c

@@ -339,6 +339,7 @@ static int stats_parse_global(char **args, int section_type, struct proxy *curpx
 			l->backlog = global.stats_fe->backlog;
 			l->accept = session_accept;
 			l->handler = process_session;
+			l->default_target = global.stats_fe->default_target;
 			l->options |= LI_O_UNLIMITED; /* don't make the peers subject to global limits */
 			l->nice = -64;  /* we want to boost priority for local stats */
 			global.maxsock += l->maxconn;

src/session.c

@@ -481,7 +481,7 @@ int session_complete(struct session *s)
 		s->si[1].flags |= SI_FL_INDEP_STR;
 
 	session_init_srv_conn(s);
-	s->target = p->default_target; /* used by peers and CLI */
+	s->target = l->default_target; /* used by peers and CLI */
 	s->pend_pos = NULL;
 
 	/* init store persistence */