net/x25: add new state X25_STATE_5

This is needed, because if the flag X25_ACCPT_APPRV_FLAG is not set on a
socket (manual call confirmation) and the channel is cleared by remote
before the manual call confirmation was sent, this situation needs to
be handled.

Signed-off-by: Martin Schiller <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/x25.h

···
 	X25_STATE_1,		/* Awaiting Call Accepted */
 	X25_STATE_2,		/* Awaiting Clear Confirmation */
 	X25_STATE_3,		/* Data Transfer */
-	X25_STATE_4		/* Awaiting Reset Confirmation */
+	X25_STATE_4,		/* Awaiting Reset Confirmation */
+	X25_STATE_5		/* Call Accepted / Call Connected pending */
 };
 
 enum {

net/x25/af_x25.c

···
 			sock_set_flag(sk, SOCK_DEAD);
 			sock_set_flag(sk, SOCK_DESTROY);
 			break;
+
+		case X25_STATE_5:
+			x25_write_internal(sk, X25_CLEAR_REQUEST);
+			x25_disconnect(sk, 0, 0, 0);
+			__x25_destroy_socket(sk);
+			goto out;
 	}
 
 	sock_orphan(sk);
···
 	if (test_bit(X25_ACCPT_APPRV_FLAG, &makex25->flags)) {
 		x25_write_internal(make, X25_CALL_ACCEPTED);
 		makex25->state = X25_STATE_3;
+	} else {
+		makex25->state = X25_STATE_5;
 	}
 
 	/*

net/x25/x25_in.c

···
 	return 0;
 }
 
+/*
+ * State machine for state 5, Call Accepted / Call Connected pending (X25_ACCPT_APPRV_FLAG).
+ * The handling of the timer(s) is in file x25_timer.c
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	switch (frametype) {
+		case X25_CLEAR_REQUEST:
+			if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) {
+				x25_write_internal(sk, X25_CLEAR_REQUEST);
+				x25->state = X25_STATE_2;
+				x25_start_t23timer(sk);
+				return 0;
+			}
+
+			x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+			x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
+			break;
+
+		default:
+			break;
+	}
+
+	return 0;
+}
+
 /* Higher level upcall for a LAPB frame */
 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 {
···
 		break;
 	case X25_STATE_4:
 		queued = x25_state4_machine(sk, skb, frametype);
+		break;
+	case X25_STATE_5:
+		queued = x25_state5_machine(sk, skb, frametype);
 		break;
 	}