tcp_retransmit_skb
int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
TRACE_EVENT(tcp_retransmit_skb,
if (tcp_retransmit_skb(sk, skb, segs))
tcp_retransmit_skb(sk, skb, 1);
if (tcp_retransmit_skb(sk, tcp_rtx_queue_head(sk), 1) > 0) {