Function rack_log_output

freebsd/netinet/tcp_stacks/rack.c:6064–6309

}

static void
rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
    uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts,
    uint8_t pass, struct rack_sendmap *hintrsm, uint32_t us_cts)
{
	struct tcp_rack *rack;
	struct rack_sendmap *rsm, *nrsm, *insret, fe;
	register uint32_t snd_max, snd_una;

	/*
	 * Add to the RACK log of packets in flight or retransmitted. If
	 * there is a TS option we will use the TS echoed, if not we will
	 * grab a TS.
	 *
	 * Retransmissions will increment the count and move the ts to its
	 * proper place. Note that if options do not include TS's then we
	 * won't be able to effectively use the ACK for an RTT on a retran.
	 *
	 * Notes about r_start and r_end. Lets consider a send starting at
	 * sequence 1 for 10 bytes. In such an example the r_start would be
	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
	 * This means that r_end is actually the first sequence for the next
	 * slot (11).
	 *
	 */
	/*
	 * If err is set what do we do XXXrrs? should we not add the thing?
	 * -- i.e. return if err != 0 or should we pretend we sent it? --
	 * i.e. proceed with add ** do this for now.
	 */
	INP_WLOCK_ASSERT(tp->t_inpcb);
	if (err)
		/*
		 * We don't log errors -- we could but snd_max does not
		 * advance in this case either.
		 */
		return;

	if (th_flags & TH_RST) {
		/*
		 * We don't log resets and we return immediately from
		 * sending
		 */
		return;
	}
	rack = (struct tcp_rack *)tp->t_fb_ptr;
	snd_una = tp->snd_una;
	if (SEQ_LEQ((seq_out + len), snd_una)) {
		/* Are sending an old segment to induce an ack (keep-alive)? */
		return;
	}
	if (SEQ_LT(seq_out, snd_una)) {
		/* huh? should we panic? */
		uint32_t end;

		end = seq_out + len;
		seq_out = snd_una;
		if (SEQ_GEQ(end, seq_out))