meter.c
/*
* Copyright (c) 2017 Nicira, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/if.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/openvswitch.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include "datapath.h"
#include "meter.h"
#define METER_HASH_BUCKETS 1024
static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
[OVS_METER_ATTR_ID] = { .type = NLA_U32, },
[OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG },
[OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
[OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED },
[OVS_METER_ATTR_USED] = { .type = NLA_U64 },
[OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG },
[OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 },
[OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 },
};
static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = {
[OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, },
[OVS_BAND_ATTR_RATE] = { .type = NLA_U32, },
[OVS_BAND_ATTR_BURST] = { .type = NLA_U32, },
[OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
};
static void ovs_meter_free(struct dp_meter *meter)
{
if (!meter)
return;
kfree_rcu(meter, rcu);
}
static struct hlist_head *meter_hash_bucket(const struct datapath *dp,
u32 meter_id)
{
return &dp->meters[meter_id & (METER_HASH_BUCKETS - 1)];
}
/* Call with ovs_mutex or RCU read lock. */
static struct dp_meter *lookup_meter(const struct datapath *dp,
u32 meter_id)
{
struct dp_meter *meter;
struct hlist_head *head;
head = meter_hash_bucket(dp, meter_id);
hlist_for_each_entry_rcu(meter, head, dp_hash_node) {
if (meter->id == meter_id)
return meter;
}
return NULL;
}
static void attach_meter(struct datapath *dp, struct dp_meter *meter)
{
struct hlist_head *head = meter_hash_bucket(dp, meter->id);
hlist_add_head_rcu(&meter->dp_hash_node, head);
}
static void detach_meter(struct dp_meter *meter)
{
ASSERT_OVSL();
if (meter)
hlist_del_rcu(&meter->dp_hash_node);
}
static struct sk_buff *
ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd,
struct ovs_header **ovs_reply_header)
{
struct sk_buff *skb;
struct ovs_header *ovs_header = info->userhdr;
skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
if (!skb)
return ERR_PTR(-ENOMEM);
*ovs_reply_header = genlmsg_put(skb, info->snd_portid,
info->snd_seq,
&dp_meter_genl_family, 0, cmd);
if (!*ovs_reply_header) {
nlmsg_free(skb);
return ERR_PTR(-EMSGSIZE);
}
(*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
return skb;
}
static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
struct dp_meter *meter)
{
struct nlattr *nla;
struct dp_meter_band *band;
u16 i;
if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
goto error;
if (!meter)
return 0;
if (nla_put(reply, OVS_METER_ATTR_STATS,
sizeof(struct ovs_flow_stats), &meter->stats) ||
nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
OVS_METER_ATTR_PAD))
goto error;
nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
if (!nla)
goto error;
band = meter->bands;
for (i = 0; i < meter->n_bands; ++i, ++band) {
struct nlattr *band_nla;
band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS,
sizeof(struct ovs_flow_stats),
&band->stats))
goto error;
nla_nest_end(reply, band_nla);
}
nla_nest_end(reply, nla);
return 0;
error:
return -EMSGSIZE;
}
static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
{
struct sk_buff *reply;
struct ovs_header *ovs_reply_header;
struct nlattr *nla, *band_nla;
int err;
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))
goto nla_put_failure;
nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
if (!nla)
goto nla_put_failure;
band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
if (!band_nla)
goto nla_put_failure;
/* Currently only DROP band type is supported. */
if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP))
goto nla_put_failure;
nla_nest_end(reply, band_nla);
nla_nest_end(reply, nla);
genlmsg_end(reply, ovs_reply_header);
return genlmsg_reply(reply, info);
nla_put_failure:
nlmsg_free(reply);
err = -EMSGSIZE;
return err;
}
static struct dp_meter *dp_meter_create(struct nlattr **a)
{
struct nlattr *nla;
int rem;
u16 n_bands = 0;
struct dp_meter *meter;
struct dp_meter_band *band;
int err;
/* Validate attributes, count the bands. */
if (!a[OVS_METER_ATTR_BANDS])
return ERR_PTR(-EINVAL);
nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem)
if (++n_bands > DP_MAX_BANDS)
return ERR_PTR(-EINVAL);
/* Allocate and set up the meter before locking anything. */
meter = kzalloc(n_bands * sizeof(struct dp_meter_band) +
sizeof(*meter), GFP_KERNEL);
if (!meter)
return ERR_PTR(-ENOMEM);
meter->id = nla_get_u32(a[OVS_METER_ATTR_ID]);
meter->used = div_u64(ktime_get_ns(), 1000 * 1000);
meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0;
meter->keep_stats = !a[OVS_METER_ATTR_CLEAR];
spin_lock_init(&meter->lock);
if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) {
meter->stats = *(struct ovs_flow_stats *)
nla_data(a[OVS_METER_ATTR_STATS]);
}
meter->n_bands = n_bands;
/* Set up meter bands. */
band = meter->bands;
nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) {
struct nlattr *attr[OVS_BAND_ATTR_MAX + 1];
u32 band_max_delta_t;
err = nla_parse((struct nlattr **)&attr, OVS_BAND_ATTR_MAX,
nla_data(nla), nla_len(nla), band_policy,
NULL);
if (err)
goto exit_free_meter;
if (!attr[OVS_BAND_ATTR_TYPE] ||
!attr[OVS_BAND_ATTR_RATE] ||
!attr[OVS_BAND_ATTR_BURST]) {
err = -EINVAL;
goto exit_free_meter;
}
band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
if (band->rate == 0) {
err = -EINVAL;
goto exit_free_meter;
}
band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
/* Figure out max delta_t that is enough to fill any bucket.
* Keep max_delta_t size to the bucket units:
* pkts => 1/1000 packets, kilobits => bits.
*
* Start with a full bucket.
*/
band->bucket = (band->burst_size + band->rate) * 1000;
band_max_delta_t = band->bucket / band->rate;
if (band_max_delta_t > meter->max_delta_t)
meter->max_delta_t = band_max_delta_t;
band++;
}
return meter;
exit_free_meter:
kfree(meter);
return ERR_PTR(err);
}
static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr **a = info->attrs;
struct dp_meter *meter, *old_meter;
struct sk_buff *reply;
struct ovs_header *ovs_reply_header;
struct ovs_header *ovs_header = info->userhdr;
struct datapath *dp;
int err;
u32 meter_id;
bool failed;
if (!a[OVS_METER_ATTR_ID]) {
return -ENODEV;
}
meter = dp_meter_create(a);
if (IS_ERR_OR_NULL(meter))
return PTR_ERR(meter);
reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
&ovs_reply_header);
if (IS_ERR(reply)) {
err = PTR_ERR(reply);
goto exit_free_meter;
}
ovs_lock();
dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
if (!dp) {
err = -ENODEV;
goto exit_unlock;
}
meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
/* Cannot fail after this. */
old_meter = lookup_meter(dp, meter_id);
detach_meter(old_meter);
attach_meter(dp, meter);
ovs_unlock();
/* Build response with the meter_id and stats from
* the old meter, if any.
*/
failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
WARN_ON(failed);
if (old_meter) {
spin_lock_bh(&old_meter->lock);
if (old_meter->keep_stats) {
err = ovs_meter_cmd_reply_stats(reply, meter_id,
old_meter);
WARN_ON(err);
}
spin_unlock_bh(&old_meter->lock);
ovs_meter_free(old_meter);
}
genlmsg_end(reply, ovs_reply_header);
return genlmsg_reply(reply, info);
exit_unlock:
ovs_unlock();
nlmsg_free(reply);
exit_free_meter:
kfree(meter);
return err;
}
static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr **a = info->attrs;
u32 meter_id;
struct ovs_header *ovs_header = info->userhdr;
struct ovs_header *ovs_reply_header;
struct datapath *dp;
int err;
struct sk_buff *reply;
struct dp_meter *meter;
if (!a[OVS_METER_ATTR_ID])
return -EINVAL;
meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
&ovs_reply_header);
if (IS_ERR(reply))
return PTR_ERR(reply);
ovs_lock();
dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
if (!dp) {
err = -ENODEV;
goto exit_unlock;
}
/* Locate meter, copy stats. */
meter = lookup_meter(dp, meter_id);
if (!meter) {
err = -ENOENT;
goto exit_unlock;
}
spin_lock_bh(&meter->lock);
err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
spin_unlock_bh(&meter->lock);
if (err)
goto exit_unlock;
ovs_unlock();
genlmsg_end(reply, ovs_reply_header);
return genlmsg_reply(reply, info);
exit_unlock:
ovs_unlock();
nlmsg_free(reply);
return err;
}
static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr **a = info->attrs;
u32 meter_id;
struct ovs_header *ovs_header = info->userhdr;
struct ovs_header *ovs_reply_header;
struct datapath *dp;
int err;
struct sk_buff *reply;
struct dp_meter *old_meter;
if (!a[OVS_METER_ATTR_ID])
return -EINVAL;
meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
&ovs_reply_header);
if (IS_ERR(reply))
return PTR_ERR(reply);
ovs_lock();
dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
if (!dp) {
err = -ENODEV;
goto exit_unlock;
}
old_meter = lookup_meter(dp, meter_id);
if (old_meter) {
spin_lock_bh(&old_meter->lock);
err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
WARN_ON(err);
spin_unlock_bh(&old_meter->lock);
detach_meter(old_meter);
}
ovs_unlock();
ovs_meter_free(old_meter);
genlmsg_end(reply, ovs_reply_header);
return genlmsg_reply(reply, info);
exit_unlock:
ovs_unlock();
nlmsg_free(reply);
return err;
}
/* Meter action execution.
*
* Return true 'meter_id' drop band is triggered. The 'skb' should be
* dropped by the caller'.
*/
bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key, u32 meter_id)
{
struct dp_meter *meter;
struct dp_meter_band *band;
long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
long long int long_delta_ms;
u32 delta_ms;
u32 cost;
int i, band_exceeded_max = -1;
u32 band_exceeded_rate = 0;
meter = lookup_meter(dp, meter_id);
/* Do not drop the packet when there is no meter. */
if (!meter)
return false;
/* Lock the meter while using it. */
spin_lock(&meter->lock);
long_delta_ms = (now_ms - meter->used); /* ms */
/* Make sure delta_ms will not be too large, so that bucket will not
* wrap around below.
*/
delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
? meter->max_delta_t : (u32)long_delta_ms;
/* Update meter statistics.
*/
meter->used = now_ms;
meter->stats.n_packets += 1;
meter->stats.n_bytes += skb->len;
/* Bucket rate is either in kilobits per second, or in packets per
* second. We maintain the bucket in the units of either bits or
* 1/1000th of a packet, correspondingly.
* Then, when rate is multiplied with milliseconds, we get the
* bucket units:
* msec * kbps = bits, and
* msec * packets/sec = 1/1000 packets.
*
* 'cost' is the number of bucket units in this packet.
*/
cost = (meter->kbps) ? skb->len * 8 : 1000;
/* Update all bands and find the one hit with the highest rate. */
for (i = 0; i < meter->n_bands; ++i) {
long long int max_bucket_size;
band = &meter->bands[i];
max_bucket_size = (band->burst_size + band->rate) * 1000LL;
band->bucket += delta_ms * band->rate;
if (band->bucket > max_bucket_size)
band->bucket = max_bucket_size;
if (band->bucket >= cost) {
band->bucket -= cost;
} else if (band->rate > band_exceeded_rate) {
band_exceeded_rate = band->rate;
band_exceeded_max = i;
}
}
if (band_exceeded_max >= 0) {
/* Update band statistics. */
band = &meter->bands[band_exceeded_max];
band->stats.n_packets += 1;
band->stats.n_bytes += skb->len;
/* Drop band triggered, let the caller drop the 'skb'. */
if (band->type == OVS_METER_BAND_TYPE_DROP) {
spin_unlock(&meter->lock);
return true;
}
}
spin_unlock(&meter->lock);
return false;
}
static struct genl_ops dp_meter_genl_ops[] = {
{ .cmd = OVS_METER_CMD_FEATURES,
.flags = 0, /* OK for unprivileged users. */
.policy = meter_policy,
.doit = ovs_meter_cmd_features
},
{ .cmd = OVS_METER_CMD_SET,
.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
* privilege.
*/
.policy = meter_policy,
.doit = ovs_meter_cmd_set,
},
{ .cmd = OVS_METER_CMD_GET,
.flags = 0, /* OK for unprivileged users. */
.policy = meter_policy,
.doit = ovs_meter_cmd_get,
},
{ .cmd = OVS_METER_CMD_DEL,
.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
* privilege.
*/
.policy = meter_policy,
.doit = ovs_meter_cmd_del
},
};
static const struct genl_multicast_group ovs_meter_multicast_group = {
.name = OVS_METER_MCGROUP,
};
struct genl_family dp_meter_genl_family __ro_after_init = {
.hdrsize = sizeof(struct ovs_header),
.name = OVS_METER_FAMILY,
.version = OVS_METER_VERSION,
.maxattr = OVS_METER_ATTR_MAX,
.netnsok = true,
.parallel_ops = true,
.ops = dp_meter_genl_ops,
.n_ops = ARRAY_SIZE(dp_meter_genl_ops),
.mcgrps = &ovs_meter_multicast_group,
.n_mcgrps = 1,
.module = THIS_MODULE,
};
int ovs_meters_init(struct datapath *dp)
{
int i;
dp->meters = kmalloc_array(METER_HASH_BUCKETS,
sizeof(struct hlist_head), GFP_KERNEL);
if (!dp->meters)
return -ENOMEM;
for (i = 0; i < METER_HASH_BUCKETS; i++)
INIT_HLIST_HEAD(&dp->meters[i]);
return 0;
}
void ovs_meters_exit(struct datapath *dp)
{
int i;
for (i = 0; i < METER_HASH_BUCKETS; i++) {
struct hlist_head *head = &dp->meters[i];
struct dp_meter *meter;
struct hlist_node *n;
hlist_for_each_entry_safe(meter, n, head, dp_hash_node)
kfree(meter);
}
kfree(dp->meters);
}
