Function unp_scan

freebsd/kern/uipc_usrreq.c:2803–2845

}

static void
unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
{
	struct mbuf *m;
	struct cmsghdr *cm;
	void *data;
	socklen_t clen, datalen;

	while (m0 != NULL) {
		for (m = m0; m; m = m->m_next) {
			if (m->m_type != MT_CONTROL)
				continue;

			cm = mtod(m, struct cmsghdr *);
			clen = m->m_len;

			while (cm != NULL) {
				if (sizeof(*cm) > clen || cm->cmsg_len > clen)
					break;

				data = CMSG_DATA(cm);
				datalen = (caddr_t)cm + cm->cmsg_len
				    - (caddr_t)data;

				if (cm->cmsg_level == SOL_SOCKET &&
				    cm->cmsg_type == SCM_RIGHTS) {
					(*op)(data, datalen /
					    sizeof(struct filedescent *));
				}

				if (CMSG_SPACE(datalen) < clen) {
					clen -= CMSG_SPACE(datalen);
					cm = (struct cmsghdr *)
					    ((caddr_t)cm + CMSG_SPACE(datalen));
				} else {
					clen = 0;
					cm = NULL;
				}
			}
		}
		m0 = m0->m_nextpkt;
	}
}

/*
 * A helper function called by VFS before socket-type vnode reclamation.