MEDIUM: session: count the frontend's connections at a single place

There are several places where we see feconn++, feconn--, totalconn++ and
an increment on the frontend's number of connections and connection rate.
This is done exactly once per session in each direction, so better take
care of this counter in the session and simplify the callers. At least it
ensures a better symmetry. It also ensures consistency as till now the
lua/spoe/peers frontend didn't have these counters properly set, which can
be useful at least for troubleshooting.

src/flt_spoe.c

@@ -1948,9 +1948,6 @@ spoe_create_appctx(struct spoe_config *conf)
 	strm->do_log = NULL;
 	strm->res.flags |= CF_READ_DONTWAIT;
 
-	conf->agent_fe.feconn++;
-	totalconn++;
-
 	task_wakeup(SPOE_APPCTX(appctx)->task, TASK_WOKEN_INIT);
 	LIST_ADDQ(&conf->agent->applets, &SPOE_APPCTX(appctx)->list);
 	conf->agent->applets_act++;

src/hlua.c

@@ -2413,10 +2413,6 @@ __LJMP static int hlua_socket_new(lua_State *L)
 	strm->flags |= SF_DIRECT | SF_ASSIGNED | SF_ADDR_SET | SF_BE_ASSIGNED;
 	strm->target = &socket_tcp.obj_type;
 
-	/* Update statistics counters. */
-	socket_proxy.feconn++; /* beconn will be increased later */
-	totalconn++;
-
 	task_wakeup(strm->task, TASK_WOKEN_INIT);
 	/* Return yield waiting for connection. */
 	return 1;

src/listener.c

@@ -527,7 +527,6 @@ void listener_accept(int fd)
 			actconn++;
 		}
 
-		totalconn++;
 		l->nbconn++;
 
 		if (l->counters) {

src/peers.c

@@ -1835,9 +1835,6 @@ static struct appctx *peer_session_create(struct peers *peers, struct peer *peer
 
 	s->res.flags |= CF_READ_DONTWAIT;
 
-	p->feconn++;/* beconn will be increased later */
-	totalconn++;
-
 	peer->appctx = appctx;
 	task_wakeup(s->task, TASK_WOKEN_INIT);
 	return appctx;

src/session.c

@@ -36,7 +36,7 @@ static struct task *session_expire_embryonic(struct task *t);
 /* Create a a new session and assign it to frontend <fe>, listener <li>,
  * origin <origin>, set the current date and clear the stick counters pointers.
  * Returns the session upon success or NULL. The session may be released using
- * session_free().
+ * session_free(). Note: <li> may be NULL.
  */
 struct session *session_new(struct proxy *fe, struct listener *li, enum obj_type *origin)
 {
@@ -53,6 +53,12 @@ struct session *session_new(struct proxy *fe, struct listener *li, enum obj_type
 		memset(sess->stkctr, 0, sizeof(sess->stkctr));
 		vars_init(&sess->vars, SCOPE_SESS);
 		sess->task = NULL;
+		fe->feconn++;
+		if (fe->feconn > fe->fe_counters.conn_max)
+			fe->fe_counters.conn_max = fe->feconn;
+		if (li)
+			proxy_inc_fe_conn_ctr(li, fe);
+		totalconn++;
 		jobs++;
 	}
 	return sess;
@@ -62,6 +68,7 @@ void session_free(struct session *sess)
 {
 	if (!LIST_ISEMPTY(&sess->streams))
 		return;
+	sess->fe->feconn--;
 	session_store_counters(sess);
 	vars_prune_per_sess(&sess->vars);
 	pool_free2(pool2_session, sess);
@@ -153,13 +160,6 @@ int session_accept_fd(struct listener *l, int cfd, struct sockaddr_storage *addr
 
 	conn_set_owner(cli_conn, sess);
 
-	p->feconn++;
-	/* This session was accepted, count it now */
-	if (p->feconn > p->fe_counters.conn_max)
-		p->fe_counters.conn_max = p->feconn;
-
-	proxy_inc_fe_conn_ctr(l, p);
-
 	/* now evaluate the tcp-request layer4 rules. We only need a session
 	 * and no stream for these rules.
 	 */
@@ -265,7 +265,6 @@ int session_accept_fd(struct listener *l, int cfd, struct sockaddr_storage *addr
 
 	/* error unrolling */
  out_free_sess:
-	p->feconn--;
 	session_free(sess);
  out_free_conn:
 	cli_conn->flags &= ~CO_FL_XPRT_TRACKED;
@@ -365,7 +364,6 @@ static void session_kill_embryonic(struct session *sess)
 	conn_force_close(conn);
 	conn_free(conn);
 
-	sess->fe->feconn--;
 	listener_release(sess->listener);
 
 	task_delete(task);

src/stream.c

@@ -2417,7 +2417,6 @@ struct task *process_stream(struct task *t)
 		return t; /* nothing more to do */
 	}
 
-	sess->fe->feconn--;
 	if (s->flags & SF_BE_ASSIGNED)
 		s->be->beconn--;