+ skb_queue_walk_from(&(sk)->sk_write_queue, skb)
+
+#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
+ skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
+
+/* This function calculates a "timeout" which is equivalent to the timeout of a
+ * TCP connection after "boundary" unsucessful, exponentially backed-off
+ * retransmissions with an initial RTO of TCP_RTO_MIN.
+ */
+static inline bool retransmits_timed_out(const struct sock *sk,
+ unsigned int boundary)
+{
+ unsigned int timeout, linear_backoff_thresh;
+
+ if (!inet_csk(sk)->icsk_retransmits)
+ return false;
+
+ linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
+
+ if (boundary <= linear_backoff_thresh)
+ timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
+ else
+ timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
+ (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
+
+ return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout;
+}