Function bpf_stats_sysctl

freebsd/net/bpf.c:2937–2999

* Handle `netstat -B' stats request */

 * Handle `netstat -B' stats request
 */
static int
bpf_stats_sysctl(SYSCTL_HANDLER_ARGS)
{
	static const struct xbpf_d zerostats;
	struct xbpf_d *xbdbuf, *xbd, tempstats;
	int index, error;
	struct bpf_if *bp;
	struct bpf_d *bd;

	/*
	 * XXX This is not technically correct. It is possible for non
	 * privileged users to open bpf devices. It would make sense
	 * if the users who opened the devices were able to retrieve
	 * the statistics for them, too.
	 */
	error = priv_check(req->td, PRIV_NET_BPF);
	if (error)
		return (error);
	/*
	 * Check to see if the user is requesting that the counters be
	 * zeroed out.  Explicitly check that the supplied data is zeroed,
	 * as we aren't allowing the user to set the counters currently.
	 */
	if (req->newptr != NULL) {
		if (req->newlen != sizeof(tempstats))
			return (EINVAL);
		memset(&tempstats, 0, sizeof(tempstats));
		error = SYSCTL_IN(req, &tempstats, sizeof(tempstats));
		if (error)
			return (error);
		if (bcmp(&tempstats, &zerostats, sizeof(tempstats)) != 0)
			return (EINVAL);
		bpf_zero_counters();
		return (0);
	}
	if (req->oldptr == NULL)
		return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd)));
	if (bpf_bpfd_cnt == 0)
		return (SYSCTL_OUT(req, 0, 0));
	xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK);
	BPF_LOCK();
	if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) {
		BPF_UNLOCK();
		free(xbdbuf, M_BPF);
		return (ENOMEM);
	}
	index = 0;
	CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
		/* Send writers-only first */
		CK_LIST_FOREACH(bd, &bp->bif_wlist, bd_next) {
			xbd = &xbdbuf[index++];
			bpfstats_fill_xbpf(xbd, bd);
		}
		CK_LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
			xbd = &xbdbuf[index++];
			bpfstats_fill_xbpf(xbd, bd);
		}
	}