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linux/net/openvswitch/meter.c
Johannes Berg 3b0f31f2b8 genetlink: make policy common to family 
Since maxattr is common, the policy can't really differ sanely,
so make it common as well.

The only user that did in fact manage to make a non-common policy
is taskstats, which has to be really careful about it (since it's
still using a common maxattr!). This is no longer supported, but
we can fake it using pre_doit.

This reduces the size of e.g. nl80211.o (which has lots of commands):

   text	   data	    bss	    dec	    hex	filename
 398745	  14323	   2240	 415308	  6564c	net/wireless/nl80211.o (before)
 397913	  14331	   2240	 414484	  65314	net/wireless/nl80211.o (after)
--------------------------------
   -832      +8       0    -824

Which is obviously just 8 bytes for each command, and an added 8
bytes for the new policy pointer. I'm not sure why the ops list is
counted as .text though.

Most of the code transformations were done using the following spatch:
    @ops@
    identifier OPS;
    expression POLICY;
    @@
    struct genl_ops OPS[] = {
    ...,
     {
    -	.policy = POLICY,
     },
    ...
    };

    @@
    identifier ops.OPS;
    expression ops.POLICY;
    identifier fam;
    expression M;
    @@
    struct genl_family fam = {
            .ops = OPS,
            .maxattr = M,
    +       .policy = POLICY,
            ...
    };

This also gets rid of devlink_nl_cmd_region_read_dumpit() accessing
the cb->data as ops, which we want to change in a later genl patch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-22 10:38:23 -04:00

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/*
* 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(struct_size(meter, bands, n_bands), 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. */
.doit = ovs_meter_cmd_features
},
{ .cmd = OVS_METER_CMD_SET,
.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
* privilege.
*/
.doit = ovs_meter_cmd_set,
},
{ .cmd = OVS_METER_CMD_GET,
.flags = 0, /* OK for unprivileged users. */
.doit = ovs_meter_cmd_get,
},
{ .cmd = OVS_METER_CMD_DEL,
.flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
* privilege.
*/
.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,
.policy = meter_policy,
.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);
}
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