Function pf_send_tcp

freebsd/netpfil/pf/pf.c:2442–2600

}

static void
pf_send_tcp(struct mbuf *replyto, const struct pf_krule *r, sa_family_t af,
    const struct pf_addr *saddr, const struct pf_addr *daddr,
    u_int16_t sport, u_int16_t dport, u_int32_t seq, u_int32_t ack,
    u_int8_t flags, u_int16_t win, u_int16_t mss, u_int8_t ttl, int tag,
    u_int16_t rtag, struct ifnet *ifp)
{
	struct pf_send_entry *pfse;
	struct mbuf	*m;
	int		 len, tlen;
#ifdef INET
	struct ip	*h = NULL;
#endif /* INET */
#ifdef INET6
	struct ip6_hdr	*h6 = NULL;
#endif /* INET6 */
	struct tcphdr	*th;
	char		*opt;
	struct pf_mtag  *pf_mtag;

	len = 0;
	th = NULL;

	/* maximum segment size tcp option */
	tlen = sizeof(struct tcphdr);
	if (mss)
		tlen += 4;

	switch (af) {
#ifdef INET
	case AF_INET:
		len = sizeof(struct ip) + tlen;
		break;
#endif /* INET */
#ifdef INET6
	case AF_INET6:
		len = sizeof(struct ip6_hdr) + tlen;
		break;
#endif /* INET6 */
	default:
		panic("%s: unsupported af %d", __func__, af);
	}

	/* Allocate outgoing queue entry, mbuf and mbuf tag. */
	pfse = malloc(sizeof(*pfse), M_PFTEMP, M_NOWAIT);
	if (pfse == NULL)
		return;
	m = m_gethdr(M_NOWAIT, MT_DATA);
	if (m == NULL) {
		free(pfse, M_PFTEMP);
		return;
	}
#ifdef MAC
	mac_netinet_firewall_send(m);
#endif
	if ((pf_mtag = pf_get_mtag(m)) == NULL) {
		free(pfse, M_PFTEMP);
		m_freem(m);