l2tp: Implement outgoing calls

Add the "l2tp create session" command to place an outgoing call.
For example, "l2tp create session tid 3" will send an OCRQ within
tunnel 3.
This allows the LNS to request establishment of a new session inside
an existing tunnel.

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

1 files changed, 174 insertions, 21 deletions

diff --git a/accel-pppd/ctrl/l2tp/l2tp.c b/accel-pppd/ctrl/l2tp/l2tp.c
index 13eb695..66658d9 100644
--- a/accel-pppd/ctrl/l2tp/l2tp.c
+++ b/accel-pppd/ctrl/l2tp/l2tp.c
@@ -248,6 +248,8 @@ static void __l2tp_session_free(void *data)
 		   __l2tp_session_free(). */
 		return;
 	case STATE_WAIT_ICCN:
+	case STATE_WAIT_OCRP:
+	case STATE_WAIT_OCCN:
 	case STATE_ESTB:
 		__sync_sub_and_fetch(&stat_starting, 1);
 		break;
@@ -992,17 +994,16 @@ out_err:
 	return -1;
 }
 
-/*static int l2tp_send_OCRQ(struct l2tp_conn_t *conn)
+static int l2tp_send_OCRQ(struct l2tp_sess_t *sess)
 {
 	struct l2tp_packet_t *pack;
 
-	pack = l2tp_packet_alloc(2, Message_Type_Outgoing_Call_Request, &conn->lac_addr);
+	pack = l2tp_packet_alloc(2, Message_Type_Outgoing_Call_Request,
+				 &sess->paren_conn->lac_addr);
 	if (!pack)
 		return -1;
-	
-	pack->hdr.sid = htons(conn->peer_sid);
 
-	if (l2tp_packet_add_int16(pack, Assigned_Session_ID, conn->sess.sid, 1))
+	if (l2tp_packet_add_int16(pack, Assigned_Session_ID, sess->sid, 1))
 		goto out_err;
 	if (l2tp_packet_add_int32(pack, Call_Serial_Number, 0, 1))
 		goto out_err;
@@ -1017,23 +1018,20 @@ out_err:
 	if (l2tp_packet_add_string(pack, Called_Number, "", 1))
 		goto out_err;
 
-	if (l2tp_send(conn, pack, 0))
+	if (l2tp_send(sess->paren_conn, pack, 0))
 		return -1;
 
-	if (!conn->timeout_timer.tpd)
-		triton_timer_add(&conn->ctx, &conn->timeout_timer, 0);
+	if (!sess->timeout_timer.tpd)
+		triton_timer_add(&sess->sctx, &sess->timeout_timer, 0);
 	else
-		triton_timer_mod(&conn->timeout_timer, 0);
-	
-	conn->state2 = STATE_WAIT_OCRP;
-	
+		triton_timer_mod(&sess->timeout_timer, 0);
+
 	return 0;
 
 out_err:
 	l2tp_packet_free(pack);
 	return -1;
-}*/
-
+}
 
 static int l2tp_recv_SCCRQ(struct l2tp_serv_t *serv, struct l2tp_packet_t *pack, struct in_pktinfo *pkt_info)
 {
@@ -1243,26 +1241,103 @@ static int l2tp_recv_ICCN(struct l2tp_sess_t *sess, struct l2tp_packet_t *pack)
 	return 0;
 }
 
-static int  l2tp_recv_OCRP(struct l2tp_sess_t *sess, struct l2tp_packet_t *pack)
+static int l2tp_recv_OCRP(struct l2tp_sess_t *sess, struct l2tp_packet_t *pack)
 {
-	if (sess->state2 != STATE_WAIT_OCRP) {
+	struct l2tp_attr_t *assigned_sid = NULL;
+	struct l2tp_attr_t *unknown_attr = NULL;
+	struct l2tp_attr_t *attr = NULL;
+
+	if (sess->state1 != STATE_WAIT_OCRP) {
 		log_ppp_warn("l2tp: unexpected OCRP\n");
-		return 0;
+		return -1;
 	}
 
-	sess->state2 = STATE_WAIT_OCCN;
+	list_for_each_entry(attr, &pack->attrs, entry) {
+		switch(attr->attr->id) {
+		case Message_Type:
+			break;
+		case Assigned_Session_ID:
+			assigned_sid = attr;
+			break;
+		default:
+			if (attr->M)
+				unknown_attr = attr;
+			else
+				log_ppp_warn("l2tp: OCRP:"
+					     " unknown attribute %i\n",
+					     attr->attr->id);
+			break;
+		}
+	}
+
+	if (assigned_sid == NULL) {
+		log_ppp_error("l2tp: OCRP: missing mandatory AVP:"
+			      " Assigned Session ID\n");
+		l2tp_session_disconnect(sess, 2, 6);
+		return -1;
+	}
+
+	/* Set peer_sid as soon as possible so that CDN
+	   will be sent to the right tunnel in case of error */
+	sess->peer_sid = assigned_sid->val.uint16;
+
+	if (unknown_attr) {
+		log_ppp_error("l2tp: OCRP: unknown mandatory attribute %i\n",
+			      unknown_attr->attr->id);
+		l2tp_session_disconnect(sess, 2, 8);
+		return -1;
+	}
+
+	sess->state1 = STATE_WAIT_OCCN;
 
 	return 0;
 }
 
 static int l2tp_recv_OCCN(struct l2tp_sess_t *sess, struct l2tp_packet_t *pack)
 {
-	if (sess->state2 != STATE_WAIT_OCCN) {
+	struct l2tp_attr_t *unknown_attr = NULL;
+	struct l2tp_attr_t *attr = NULL;
+
+	if (sess->state1 != STATE_WAIT_OCCN) {
 		log_ppp_warn("l2tp: unexpected OCCN\n");
 		return 0;
 	}
 
-	sess->state2 = STATE_ESTB;
+	triton_timer_del(&sess->timeout_timer);
+
+	list_for_each_entry(attr, &pack->attrs, entry) {
+		switch (attr->attr->id) {
+		case Message_Type:
+		case TX_Speed:
+		case Framing_Type:
+			break;
+		default:
+			if (attr->M)
+				unknown_attr = attr;
+			else
+				log_ppp_warn("l2tp: OCCN:"
+					     " unknown attribute %i\n",
+					     attr->attr->id);
+			break;
+		}
+	}
+
+	if (unknown_attr) {
+		log_ppp_error("l2tp: OCCN: unknown mandatory attribute %i\n",
+			      unknown_attr->attr->id);
+		l2tp_session_disconnect(sess, 2, 8);
+		return -1;
+	}
+
+	sess->state1 = STATE_ESTB;
+
+	if (l2tp_session_connect(sess) < 0) {
+		l2tp_session_disconnect(sess, 2, 4);
+		return -1;
+	}
+
+	if (l2tp_send_ZLB(sess->paren_conn) < 0)
+		return -1;
 
 	return 0;
 }
@@ -1286,6 +1361,44 @@ static int l2tp_recv_SLI(struct l2tp_conn_t *conn, struct l2tp_packet_t *pack)
 	return 0;
 }
 
+static void l2tp_session_outcall(void *data)
+{
+	struct l2tp_sess_t *sess = data;
+
+	if (l2tp_send_OCRQ(sess) < 0) {
+		log_ppp_error("l2tp: impossible to place call:"
+			      " error while sending OCRQ\n");
+		return;
+	}
+	sess->state1 = STATE_WAIT_OCRP;
+}
+
+static void l2tp_tunnel_create_session(void *data)
+{
+	struct l2tp_conn_t *conn = data;
+	struct l2tp_sess_t *sess = NULL;
+
+	if (conn->state != STATE_ESTB) {
+		log_ppp_error("l2tp: impossible to place call:"
+			      " tunnel is not connected\n");
+		return;
+	}
+
+	sess = l2tp_tunnel_alloc_session(conn);
+	if (sess == NULL) {
+		log_ppp_error("l2tp: impossible to place call:"
+			      " no more session available\n");
+		return;
+	}
+	if (l2tp_tunnel_confirm_session(sess) < 0) {
+		log_ppp_error("l2tp: impossible to place call:"
+			      " session initialisation failed\n");
+		l2tp_tunnel_cancel_session(sess);
+		return;
+	}
+	triton_context_call(&sess->sctx, l2tp_session_outcall, sess);
+}
+
 static void l2tp_session_recv(void *data)
 {
 	struct triton_context_t *ctx = triton_context_self();
@@ -1600,6 +1713,43 @@ static int show_stat_exec(const char *cmd, char * const *fields, int fields_cnt,
 	return CLI_CMD_OK;
 }
 
+static int l2tp_create_session_exec(const char *cmd, char * const *fields,
+				    int fields_cnt, void *client)
+{
+	struct l2tp_conn_t *conn = NULL;
+	long int tid;
+	int res;
+
+	if (fields_cnt != 5)
+		return CLI_CMD_SYNTAX;
+
+	if (strcmp("tid", fields[3]) != 0)
+		return CLI_CMD_SYNTAX;
+
+	if (u_readlong(&tid, fields[4], 1, L2TP_MAX_TID - 1) < 0)
+		return CLI_CMD_INVAL;
+
+	pthread_mutex_lock(&l2tp_lock);
+	conn = l2tp_conn[tid];
+	if (conn) {
+		triton_context_call(&conn->ctx,
+				    l2tp_tunnel_create_session, conn);
+		res = CLI_CMD_OK;
+	} else
+		res = CLI_CMD_INVAL;
+	pthread_mutex_unlock(&l2tp_lock);
+
+	return res;
+}
+
+static void l2tp_create_session_help(char * const *fields, int fields_cnt,
+				     void *client)
+{
+	cli_send(client,
+		 "l2tp create session tid <tid>"
+		 " - place new call in tunnel <tid>\r\n");
+}
+
 void __export l2tp_get_stat(unsigned int **starting, unsigned int **active)
 {
 	*starting = &stat_starting;
@@ -1678,7 +1828,10 @@ static void l2tp_init(void)
 	start_udp_server();
 
 	cli_register_simple_cmd2(&show_stat_exec, NULL, 2, "show", "stat");
-	
+	cli_register_simple_cmd2(l2tp_create_session_exec,
+				 l2tp_create_session_help, 3,
+				 "l2tp", "create", "session");
+
 	triton_event_register_handler(EV_CONFIG_RELOAD, (triton_event_func)load_config);
 }