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Message-Id: <1587686886-16347-3-git-send-email-xiangxia.m.yue@gmail.com>
Date: Fri, 24 Apr 2020 08:08:03 +0800
From: xiangxia.m.yue@...il.com
To: pshelar@....org, azhou@....org, blp@....org, u9012063@...il.com
Cc: netdev@...r.kernel.org, dev@...nvswitch.org,
Tonghao Zhang <xiangxia.m.yue@...il.com>
Subject: [PATCH net-next v4 2/5] net: openvswitch: set max limitation to meters
From: Tonghao Zhang <xiangxia.m.yue@...il.com>
Don't allow user to create meter unlimitedly, which may cause
to consume a large amount of kernel memory. The max number
supported is decided by physical memory and 20K meters as default.
Cc: Pravin B Shelar <pshelar@....org>
Cc: Andy Zhou <azhou@....org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@...il.com>
Acked-by: Pravin B Shelar <pshelar@....org>
---
net/openvswitch/meter.c | 57 +++++++++++++++++++++++++++++++++--------
net/openvswitch/meter.h | 2 ++
2 files changed, 49 insertions(+), 10 deletions(-)
diff --git a/net/openvswitch/meter.c b/net/openvswitch/meter.c
index f806ded1dd0a..372f4565872d 100644
--- a/net/openvswitch/meter.c
+++ b/net/openvswitch/meter.c
@@ -12,6 +12,7 @@
#include <linux/openvswitch.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
+#include <linux/swap.h>
#include <net/netlink.h>
#include <net/genetlink.h>
@@ -137,6 +138,7 @@ static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
{
struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
u32 hash = meter_hash(ti, meter->id);
+ int err;
/* In generally, slots selected should be empty, because
* OvS uses id-pool to fetch a available id.
@@ -147,16 +149,24 @@ static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
dp_meter_instance_insert(ti, meter);
/* That function is thread-safe. */
- if (++tbl->count >= ti->n_meters)
- if (dp_meter_instance_realloc(tbl, ti->n_meters * 2))
- goto expand_err;
+ tbl->count++;
+ if (tbl->count >= tbl->max_meters_allowed) {
+ err = -EFBIG;
+ goto attach_err;
+ }
+
+ if (tbl->count >= ti->n_meters &&
+ dp_meter_instance_realloc(tbl, ti->n_meters * 2)) {
+ err = -ENOMEM;
+ goto attach_err;
+ }
return 0;
-expand_err:
+attach_err:
dp_meter_instance_remove(ti, meter);
tbl->count--;
- return -ENOMEM;
+ return err;
}
static int detach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
@@ -266,18 +276,32 @@ static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
{
- struct sk_buff *reply;
+ struct ovs_header *ovs_header = info->userhdr;
struct ovs_header *ovs_reply_header;
struct nlattr *nla, *band_nla;
- int err;
+ struct sk_buff *reply;
+ struct datapath *dp;
+ int err = -EMSGSIZE;
reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
&ovs_reply_header);
if (IS_ERR(reply))
return PTR_ERR(reply);
- if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS, U32_MAX) ||
- nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
+ ovs_lock();
+ dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+ if (!dp) {
+ err = -ENODEV;
+ goto exit_unlock;
+ }
+
+ if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS,
+ dp->meter_tbl.max_meters_allowed))
+ goto exit_unlock;
+
+ ovs_unlock();
+
+ if (nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
goto nla_put_failure;
nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
@@ -296,9 +320,10 @@ static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
genlmsg_end(reply, ovs_reply_header);
return genlmsg_reply(reply, info);
+exit_unlock:
+ ovs_unlock();
nla_put_failure:
nlmsg_free(reply);
- err = -EMSGSIZE;
return err;
}
@@ -699,15 +724,27 @@ int ovs_meters_init(struct datapath *dp)
{
struct dp_meter_table *tbl = &dp->meter_tbl;
struct dp_meter_instance *ti;
+ unsigned long free_mem_bytes;
ti = dp_meter_instance_alloc(DP_METER_ARRAY_SIZE_MIN);
if (!ti)
return -ENOMEM;
+ /* Allow meters in a datapath to use ~3.12% of physical memory. */
+ free_mem_bytes = nr_free_buffer_pages() * (PAGE_SIZE >> 5);
+ tbl->max_meters_allowed = min(free_mem_bytes / sizeof(struct dp_meter),
+ DP_METER_NUM_MAX);
+ if (!tbl->max_meters_allowed)
+ goto out_err;
+
rcu_assign_pointer(tbl->ti, ti);
tbl->count = 0;
return 0;
+
+out_err:
+ dp_meter_instance_free(ti);
+ return -ENOMEM;
}
void ovs_meters_exit(struct datapath *dp)
diff --git a/net/openvswitch/meter.h b/net/openvswitch/meter.h
index f52052d30a16..61a3ca43cd77 100644
--- a/net/openvswitch/meter.h
+++ b/net/openvswitch/meter.h
@@ -20,6 +20,7 @@ struct datapath;
#define DP_MAX_BANDS 1
#define DP_METER_ARRAY_SIZE_MIN BIT_ULL(10)
+#define DP_METER_NUM_MAX (200000UL)
struct dp_meter_band {
u32 type;
@@ -50,6 +51,7 @@ struct dp_meter_instance {
struct dp_meter_table {
struct dp_meter_instance __rcu *ti;
u32 count;
+ u32 max_meters_allowed;
};
extern struct genl_family dp_meter_genl_family;
--
2.23.0
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