Function ctf_fixed_maxseg

freebsd/netinet/tcp_stacks/rack_bbr_common.c:817–859

}

uint32_t
ctf_fixed_maxseg(struct tcpcb *tp)
{
	int optlen;

	if (tp->t_flags & TF_NOOPT)
		return (tp->t_maxseg);

	/*
	 * Here we have a simplified code from tcp_addoptions(),
	 * without a proper loop, and having most of paddings hardcoded.
	 * We only consider fixed options that we would send every
	 * time I.e. SACK is not considered.
	 *
	 */
#define	PAD(len)	((((len) / 4) + !!((len) % 4)) * 4)
	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
		if (tp->t_flags & TF_RCVD_TSTMP)
			optlen = TCPOLEN_TSTAMP_APPA;
		else
			optlen = 0;
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
		if (tp->t_flags & TF_SIGNATURE)
			optlen += PAD(TCPOLEN_SIGNATURE);
#endif
	} else {
		if (tp->t_flags & TF_REQ_TSTMP)
			optlen = TCPOLEN_TSTAMP_APPA;
		else
			optlen = PAD(TCPOLEN_MAXSEG);
		if (tp->t_flags & TF_REQ_SCALE)
			optlen += PAD(TCPOLEN_WINDOW);
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
		if (tp->t_flags & TF_SIGNATURE)
			optlen += PAD(TCPOLEN_SIGNATURE);
#endif
		if (tp->t_flags & TF_SACK_PERMIT)
			optlen += PAD(TCPOLEN_SACK_PERMITTED);
	}
#undef PAD
	optlen = min(optlen, TCP_MAXOLEN);
	return (tp->t_maxseg - optlen);
}

void
ctf_log_sack_filter(struct tcpcb *tp, int num_sack_blks, struct sackblk *sack_blocks)