L2TP: Use different states for handling sessions and tunnels

Use the "state" field (struct l2tp_conn_t) for tracking tunnel
states and "state1" (struct l2tp_sess_t) for sessions. The
meaning of the STATE_* has been slightly modified:

  * STATE_WAIT_SCCN (tunnel): no modification.

  * STATE_WAIT_ICRQ (session): now unused. Acceptation of ICRQ
    messages now depend on the tunnel state (STATE_ESTB).

  * STATE_WAIT_ICCN (session): no modification.

  * STATE_ESTB (tunnel and session): for tunnels, means that the
    tunnel is ready to accept new sessions. For sessions, means
    that the L2TP session is established, but that it doesn't
    carry any PPP session yet.

  * STATE_PPP (session): the session is in use (i.e. it is
    established and carries a PPP session).

  * STATE_FIN (tunnel): the tunnel is being closed.

  * STATE_CLOSE (tunnel and session): default state after
    allocation/free. For session, this is also the state
    used once disconnected.

Since outgoing calls are not implemented yet, STATE_WAIT_OCRP and
STATE_WAIT_OCCN are not used.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>

1 files changed, 27 insertions, 17 deletions

diff --git a/accel-pppd/ctrl/l2tp/l2tp.c b/accel-pppd/ctrl/l2tp/l2tp.c
index d436de0e..c4ff01be 100644
--- a/accel-pppd/ctrl/l2tp/l2tp.c
+++ b/accel-pppd/ctrl/l2tp/l2tp.c
@@ -121,13 +121,19 @@ static int l2tp_conn_read(struct triton_md_handler_t *);
 
 static void l2tp_session_free(struct l2tp_conn_t *conn)
 {
-	if (conn->state == STATE_PPP) {
+	switch (conn->sess.state1) {
+	case STATE_PPP:
 		__sync_sub_and_fetch(&stat_active, 1);
-		conn->state = STATE_FIN;
 		ap_session_terminate(&conn->sess.ppp.ses,
 				     TERM_USER_REQUEST, 1);
-	} else if (conn->state != STATE_FIN)
+		break;
+	case STATE_WAIT_ICCN:
+	case STATE_ESTB:
 		__sync_sub_and_fetch(&stat_starting, 1);
+		break;
+	default:
+		return;
+	}
 
 	if (conn->sess.ppp.fd != -1)
 		close(conn->sess.ppp.fd);
@@ -140,12 +146,17 @@ static void l2tp_session_free(struct l2tp_conn_t *conn)
 		_free(conn->sess.ppp.ses.chan_name);
 	_free(conn->sess.ctrl.calling_station_id);
 	_free(conn->sess.ctrl.called_station_id);
+
+	conn->sess.state1 = STATE_CLOSE;
 }
 
 static void l2tp_tunnel_free(struct l2tp_conn_t *conn)
 {
 	struct l2tp_packet_t *pack;
 
+	if (conn->state == STATE_CLOSE)
+		return;
+
 	l2tp_session_free(conn);
 
 	triton_md_unregister_handler(&conn->hnd);
@@ -178,6 +189,8 @@ static void l2tp_tunnel_free(struct l2tp_conn_t *conn)
 	if (conn->challenge_len)
 	    _free(conn->challenge.octets);
 
+	conn->state = STATE_CLOSE;
+
 	mempool_free(conn);
 }
 
@@ -229,7 +242,7 @@ static void l2tp_ppp_finished(struct ap_session *ses)
 
 	log_ppp_debug("l2tp: ppp finished\n");
 
-	if (conn->state != STATE_FIN) {
+	if (conn->sess.state1 == STATE_PPP) {
 		__sync_sub_and_fetch(&stat_active, 1);
 		if (l2tp_terminate(conn, 0, 0))
 			triton_context_call(&conn->ctx, (triton_event_func)l2tp_tunnel_free, conn);
@@ -272,10 +285,9 @@ static int l2tp_session_alloc(struct l2tp_conn_t *conn)
 static void l2tp_conn_close(struct triton_context_t *ctx)
 {
 	struct l2tp_conn_t *conn = container_of(ctx, typeof(*conn), ctx);
-	
-	if (conn->state == STATE_PPP) {
+
+	if (conn->sess.state1 == STATE_PPP) {
 		__sync_sub_and_fetch(&stat_active, 1);
-		conn->state = STATE_FIN;
 		ap_session_terminate(&conn->sess.ppp.ses, TERM_ADMIN_RESET, 1);
 	}
 	
@@ -459,7 +471,7 @@ static int l2tp_session_connect(struct l2tp_conn_t *conn)
 	__sync_sub_and_fetch(&stat_starting, 1);
 	__sync_add_and_fetch(&stat_active, 1);
 
-	conn->state = STATE_PPP;
+	conn->sess.state1 = STATE_PPP;
 
 	return 0;
 
@@ -816,7 +828,6 @@ static int l2tp_recv_SCCCN(struct l2tp_conn_t *conn, struct l2tp_packet_t *pack)
 			return -1;
 		}
 		conn->state = STATE_ESTB;
-		conn->sess.state1 = STATE_WAIT_ICRQ;
 	}
 	else
 		log_ppp_warn("l2tp: unexpected SCCCN\n");
@@ -843,11 +854,16 @@ static int l2tp_recv_ICRQ(struct l2tp_conn_t *conn, struct l2tp_packet_t *pack)
 	struct l2tp_attr_t *attr;
 	struct l2tp_attr_t *assigned_sid = NULL;
 
-	if (conn->sess.state1 != STATE_WAIT_ICRQ) {
+	if (conn->state != STATE_ESTB) {
 		log_ppp_warn("l2tp: unexpected ICRQ\n");
 		return 0;
 	}
 
+	if (conn->sess.state1 != STATE_CLOSE) {
+		log_ppp_warn("l2tp: no more session available\n");
+		return 0;
+	}
+
 	list_for_each_entry(attr, &pack->attrs, entry) {
 		switch(attr->attr->id) {
 			case Assigned_Session_ID:
@@ -946,13 +962,7 @@ static int l2tp_recv_CDN(struct l2tp_conn_t *conn, struct l2tp_packet_t *pack)
 		return 0;
 	}
 
-	if (conn->state == STATE_PPP) {
-		__sync_sub_and_fetch(&stat_active, 1);
-		conn->state = STATE_FIN;
-		ap_session_terminate(&conn->sess.ppp.ses,
-				     TERM_USER_REQUEST, 1);
-	}
-	
+	l2tp_session_free(conn);
 	if (l2tp_terminate(conn, 0, 0))
 		return -1;