Function sbappend_locked

freebsd/kern/uipc_sockbuf.c:868–912

* Append mbuf chain m to the last record in the socket buffer sb. The * additional space associated the mbuf chain is recorded in sb. Empty mbufs * are discarded and mbufs are compacted where possible. */

 * are discarded and mbufs are compacted where possible.
 */
void
sbappend_locked(struct sockbuf *sb, struct mbuf *m, int flags)
{
	struct mbuf *n;

	SOCKBUF_LOCK_ASSERT(sb);

	if (m == NULL)
		return;
	sbm_clrprotoflags(m, flags);
	SBLASTRECORDCHK(sb);
	n = sb->sb_mb;
	if (n) {
		while (n->m_nextpkt)
			n = n->m_nextpkt;
		do {
			if (n->m_flags & M_EOR) {
				sbappendrecord_locked(sb, m); /* XXXXXX!!!! */
				return;
			}
		} while (n->m_next && (n = n->m_next));
	} else {
		/*
		 * XXX Would like to simply use sb_mbtail here, but
		 * XXX I need to verify that I won't miss an EOR that
		 * XXX way.
		 */
		if ((n = sb->sb_lastrecord) != NULL) {
			do {
				if (n->m_flags & M_EOR) {
					sbappendrecord_locked(sb, m); /* XXXXXX!!!! */
					return;
				}
			} while (n->m_next && (n = n->m_next));
		} else {
			/*
			 * If this is the first record in the socket buffer,
			 * it's also the last record.
			 */
			sb->sb_lastrecord = m;
		}
	}
	sbcompress(sb, m, n);
	SBLASTRECORDCHK(sb);
}

/*
 * Append mbuf chain m to the last record in the socket buffer sb.  The