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dpif-netlink: Probe for broken Linux meter implementations.

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Meter support was introduced in Linux 4.15.  In some versions of Linux
4.15, 4.16, and 4.17, there was a bug that never set the id when the
meter was created, so all meters essentially had an id of zero.  This
commit adds a probe to check for that condition and disable meters on
those kernels.

Signed-off-by: Justin Pettit <jpettit@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
This commit is contained in:
Justin Pettit
2018-08-08 17:31:17 -07:00
parent 8101f03fcd
commit 92d0d515d6
1 changed files with 59 additions and 0 deletions
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59
lib/dpif-netlink.c
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@@ -53,6 +53,7 @@
#include "openvswitch/ofpbuf.h"
#include "openvswitch/poll-loop.h"
#include "openvswitch/shash.h"
#include "openvswitch/thread.h"
#include "openvswitch/vlog.h"
#include "packets.h"
#include "random.h"
@@ -2926,6 +2927,12 @@ dpif_netlink_ct_flush(struct dpif *dpif OVS_UNUSED, const uint16_t *zone,
#define DP_SUPPORTED_METER_FLAGS_MASK \
(OFPMF13_STATS | OFPMF13_PKTPS | OFPMF13_KBPS | OFPMF13_BURST)
/* Meter support was introduced in Linux 4.15. In some versions of
* Linux 4.15, 4.16, and 4.17, there was a bug that never set the id
* when the meter was created, so all meters essentially had an id of
* zero. Check for that condition and disable meters on those kernels. */
static bool probe_broken_meters(struct dpif *);
static void
dpif_netlink_meter_init(struct dpif_netlink *dpif, struct ofpbuf *buf,
void *stub, size_t size, uint32_t command)
@@ -2977,6 +2984,11 @@ static void
dpif_netlink_meter_get_features(const struct dpif *dpif_,
struct ofputil_meter_features *features)
{
if (probe_broken_meters(CONST_CAST(struct dpif *, dpif_))) {
features = NULL;
return;
}
struct ofpbuf buf, *msg;
uint64_t stub[1024 / 8];
@@ -3033,6 +3045,10 @@ static int
dpif_netlink_meter_set(struct dpif *dpif_, ofproto_meter_id meter_id,
struct ofputil_meter_config *config)
{
if (probe_broken_meters(dpif_)) {
return ENOMEM;
}
struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
struct ofpbuf buf, *msg;
uint64_t stub[1024 / 8];
@@ -3206,6 +3222,49 @@ dpif_netlink_meter_del(struct dpif *dpif, ofproto_meter_id meter_id,
OVS_METER_CMD_DEL);
}
static bool
probe_broken_meters__(struct dpif *dpif)
{
/* This test is destructive if a probe occurs while ovs-vswitchd is
* running (e.g., an ovs-dpctl meter command is called), so choose a
* random high meter id to make this less likely to occur. */
ofproto_meter_id id1 = { 54545401 };
ofproto_meter_id id2 = { 54545402 };
struct ofputil_meter_band band = {OFPMBT13_DROP, 0, 1, 0};
struct ofputil_meter_config config1 = { 1, OFPMF13_KBPS, 1, &band};
struct ofputil_meter_config config2 = { 2, OFPMF13_KBPS, 1, &band};
/* Try adding two meters and make sure that they both come back with
* the proper meter id. */
dpif_netlink_meter_set(dpif, id1, &config1);
dpif_netlink_meter_set(dpif, id2, &config2);
if (dpif_netlink_meter_get(dpif, id1, NULL, 0)
|| dpif_netlink_meter_get(dpif, id2, NULL, 0)) {
VLOG_INFO("The kernel module has a broken meter implementation.");
return true;
}
dpif_netlink_meter_del(dpif, id1, NULL, 0);
dpif_netlink_meter_del(dpif, id2, NULL, 0);
return false;
}
static bool
probe_broken_meters(struct dpif *dpif)
{
/* This is a once-only test because currently OVS only has at most a single
* Netlink capable datapath on any given platform. */
static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
static bool broken_meters = false;
if (ovsthread_once_start(&once)) {
broken_meters = probe_broken_meters__(dpif);
ovsthread_once_done(&once);
}
return broken_meters;
}
const struct dpif_class dpif_netlink_class = {
"system",