[MINOR] Add active connection list to server

The motivation for this is to allow iteration of all the connections
of a server without the expense of iterating over the global list
of connections.

The first use of this will be to implement an option to close connections
associated with a server when is is marked as being down or in maintenance
mode.

include/proto/session.h

@@ -225,6 +225,21 @@ static void inline session_inc_http_err_ctr(struct session *s)
 	}
 }
 
+static void inline session_add_srv_conn(struct session *sess, struct server *srv)
+{
+	sess->srv_conn = srv;
+	LIST_ADD(&srv->actconns, &sess->by_srv);
+}
+
+static void inline session_del_srv_conn(struct session *sess)
+{
+	if (!sess->srv_conn)
+		return;
+
+	sess->srv_conn = NULL;
+	LIST_DEL(&sess->by_srv);
+}
+
 #endif /* _PROTO_SESSION_H */
 
 /*

include/types/server.h

@@ -101,6 +101,7 @@ struct server {
 	struct srvcounters counters;		/* statistics counters */
 
 	struct list pendconns;			/* pending connections */
+	struct list actconns;			/* active connections */
 	struct task *check;                     /* the task associated to the health check processing */
 
 	struct sockaddr_storage addr;		/* the address to connect to */

include/types/session.h

@@ -157,6 +157,7 @@ enum {
  */
 struct session {
 	struct list list;			/* position in global sessions list */
+	struct list by_srv;			/* position in server session list */
 	struct list back_refs;			/* list of users tracking this session */
 	struct task *task;			/* the task associated with this session */
 	/* application specific below */

src/cfgparse.c

@@ -3922,6 +3922,7 @@ stats_error_parsing:
 			newsrv->conf.file = file;
 			newsrv->conf.line = linenum;
 
+			LIST_INIT(&newsrv->actconns);
 			LIST_INIT(&newsrv->pendconns);
 			do_check = 0;
 			newsrv->state = SRV_RUNNING; /* early server setup */

src/peers.c

@@ -1185,7 +1185,7 @@ static struct session *peer_session_create(struct peer *peer, struct peer_sessio
 	stream_sock_prepare_interface(&s->si[1]);
 	s->si[1].release = NULL;
 
-	s->srv_conn = NULL;
+	session_del_srv_conn(s);
 	clear_target(&s->target);
 	s->pend_pos = NULL;
 

src/proto_http.c

@@ -7593,7 +7593,7 @@ void http_reset_txn(struct session *s)
 
 	s->be = s->fe;
 	s->logs.logwait = s->fe->to_log;
-	s->srv_conn = NULL;
+	session_del_srv_conn(s);
 	clear_target(&s->target);
 	/* re-init store persistence */
 	s->store_count = 0;

src/queue.c

@@ -16,6 +16,7 @@
 
 #include <proto/queue.h>
 #include <proto/server.h>
+#include <proto/session.h>
 #include <proto/stream_interface.h>
 #include <proto/task.h>
 
@@ -122,7 +123,7 @@ struct session *pendconn_get_next_sess(struct server *srv, struct proxy *px)
 	/* we want to note that the session has now been assigned a server */
 	sess->flags |= SN_ASSIGNED;
 	set_target_server(&sess->target, srv);
-	sess->srv_conn = srv;
+	session_add_srv_conn(sess, srv);
 	srv->served++;
 	if (px->lbprm.server_take_conn)
 		px->lbprm.server_take_conn(srv);

src/session.c

@@ -201,7 +201,7 @@ int session_accept(struct listener *l, int cfd, struct sockaddr_storage *addr)
 	if (likely(s->fe->options2 & PR_O2_INDEPSTR))
 		s->si[1].flags |= SI_FL_INDEP_STR;
 
-	s->srv_conn = NULL;
+	session_del_srv_conn(s);
 	clear_target(&s->target);
 	s->pend_pos = NULL;
 
@@ -2140,14 +2140,14 @@ void sess_change_server(struct session *sess, struct server *newsrv)
 		sess->srv_conn->served--;
 		if (sess->srv_conn->proxy->lbprm.server_drop_conn)
 			sess->srv_conn->proxy->lbprm.server_drop_conn(sess->srv_conn);
-		sess->srv_conn = NULL;
+		session_del_srv_conn(sess);
 	}
 
 	if (newsrv) {
 		newsrv->served++;
 		if (newsrv->proxy->lbprm.server_take_conn)
 			newsrv->proxy->lbprm.server_take_conn(newsrv);
-		sess->srv_conn = newsrv;
+		session_add_srv_conn(sess, newsrv);
 	}
 }