find_dest() via new_dest() may return NULL

* stefani@seibold.net | 2010-12-31 10:29:45 [+0100]:

+static int udpcp_sendmsg(struct kiocb *iocb, struct sock *sk,
+			 struct msghdr *msg, size_t len)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct udpcp_sock *usk = udpcp_sk(sk);
+	struct ipcm_cookie *ipc;
+	struct rtable *rt = NULL;
+	int free = 0;
+	int connected = 0;
+	__be32 daddr, faddr, saddr;
+	__be16 dport;
+	u8 tos;
+	int err = 0;
+	int corkreq = usk->udpsock.corkflag || msg->msg_flags & MSG_MORE;
+	int (*getfrag) (void *, char *, int, int, int, struct sk_buff *);
+	struct udpcp_dest *dest;
+
+	if (len > UDPCP_MAX_MSGSIZE)
+		return -EMSGSIZE;
+
+	/*
+	 * Check the flags.
+	 */
+	if (msg->msg_flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	/*
+	 * check if socket is binded to a port
+	 */
+	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK) || !inet->inet_num)
+		return -ENOTCONN;
+
+	/*
+	 * Get and verify the address.
+	 */
+	if (msg->msg_name) {
+		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
+		if (msg->msg_namelen < sizeof(*usin))
+			return -EINVAL;
+		if (usin->sin_family != AF_INET) {
+			if (usin->sin_family != AF_UNSPEC)
+				return -EAFNOSUPPORT;
+		}
+
+		daddr = usin->sin_addr.s_addr;
+		dport = usin->sin_port;
+	} else {
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -EDESTADDRREQ;
+		daddr = inet->inet_daddr;
+		dport = inet->inet_dport;
+		/* Open fast path for connected socket.
+		   Route will not be used, if at least one option is set.
+		 */
+		connected = 1;
+	}
+
+	if (dport == 0)
+		return -EINVAL;
+
+	dest = find_dest(sk, daddr, dport);

    if (!dest)
			return -ENOBUFS;