Function sbappendaddr_locked_internal

freebsd/kern/uipc_sockbuf.c:1143–1187

Helper routine that appends data, control, and address to a sockbuf. */

/* Helper routine that appends data, control, and address to a sockbuf. */
static int
sbappendaddr_locked_internal(struct sockbuf *sb, const struct sockaddr *asa,
    struct mbuf *m0, struct mbuf *control, struct mbuf *ctrl_last)
{
	struct mbuf *m, *n, *nlast;
#if MSIZE <= 256
	if (asa->sa_len > MLEN)
		return (0);
#endif
	m = m_get(M_NOWAIT, MT_SONAME);
	if (m == NULL)
		return (0);
	m->m_len = asa->sa_len;
	bcopy(asa, mtod(m, caddr_t), asa->sa_len);
	if (m0) {
		m_clrprotoflags(m0);
		m_tag_delete_chain(m0, NULL);
		/*
		 * Clear some persistent info from pkthdr.
		 * We don't use m_demote(), because some netgraph consumers
		 * expect M_PKTHDR presence.
		 */
		m0->m_pkthdr.rcvif = NULL;
		m0->m_pkthdr.flowid = 0;
		m0->m_pkthdr.csum_flags = 0;
		m0->m_pkthdr.fibnum = 0;
		m0->m_pkthdr.rsstype = 0;
	}
	if (ctrl_last)
		ctrl_last->m_next = m0;	/* concatenate data to control */
	else
		control = m0;
	m->m_next = control;
	for (n = m; n->m_next != NULL; n = n->m_next)
		sballoc(sb, n);
	sballoc(sb, n);
	nlast = n;
	SBLINKRECORD(sb, m);

	sb->sb_mbtail = nlast;
	SBLASTMBUFCHK(sb);

	SBLASTRECORDCHK(sb);
	return (1);
}

/*
 * Append address and data, and optionally, control (ancillary) data to the