linux/net/sched/act_sample.c

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/*
* net/sched/act_sample.c - Packet sampling tc action
* Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/gfp.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_sample.h>
#include <net/tc_act/tc_sample.h>
#include <net/psample.h>
#include <linux/if_arp.h>
static unsigned int sample_net_id;
static struct tc_action_ops act_sample_ops;
static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
[TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) },
[TCA_SAMPLE_RATE] = { .type = NLA_U32 },
[TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 },
[TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 },
};
static int tcf_sample_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a, int ovr,
int bind)
{
struct tc_action_net *tn = net_generic(net, sample_net_id);
struct nlattr *tb[TCA_SAMPLE_MAX + 1];
struct psample_group *psample_group;
struct tc_sample *parm;
struct tcf_sample *s;
bool exists = false;
int ret;
if (!nla)
return -EINVAL;
ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL);
if (ret < 0)
return ret;
if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
!tb[TCA_SAMPLE_PSAMPLE_GROUP])
return -EINVAL;
parm = nla_data(tb[TCA_SAMPLE_PARMS]);
exists = tcf_idr_check(tn, parm->index, a, bind);
if (exists && bind)
return 0;
if (!exists) {
ret = tcf_idr_create(tn, parm->index, est, a,
&act_sample_ops, bind, false);
if (ret)
return ret;
ret = ACT_P_CREATED;
} else {
tcf_idr_release(*a, bind);
if (!ovr)
return -EEXIST;
}
s = to_sample(*a);
s->tcf_action = parm->action;
s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
psample_group = psample_group_get(net, s->psample_group_num);
if (!psample_group) {
if (ret == ACT_P_CREATED)
tcf_idr_release(*a, bind);
return -ENOMEM;
}
RCU_INIT_POINTER(s->psample_group, psample_group);
if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
s->truncate = true;
s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
}
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
return ret;
}
static void tcf_sample_cleanup(struct tc_action *a, int bind)
{
struct tcf_sample *s = to_sample(a);
struct psample_group *psample_group;
psample_group = rtnl_dereference(s->psample_group);
RCU_INIT_POINTER(s->psample_group, NULL);
psample_group_put(psample_group);
}
static bool tcf_sample_dev_ok_push(struct net_device *dev)
{
switch (dev->type) {
case ARPHRD_TUNNEL:
case ARPHRD_TUNNEL6:
case ARPHRD_SIT:
case ARPHRD_IPGRE:
case ARPHRD_VOID:
case ARPHRD_NONE:
return false;
default:
return true;
}
}
static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_sample *s = to_sample(a);
struct psample_group *psample_group;
int retval;
int size;
int iif;
int oif;
tcf_lastuse_update(&s->tcf_tm);
bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
retval = READ_ONCE(s->tcf_action);
rcu_read_lock();
psample_group = rcu_dereference(s->psample_group);
/* randomly sample packets according to rate */
if (psample_group && (prandom_u32() % s->rate == 0)) {
if (!skb_at_tc_ingress(skb)) {
iif = skb->skb_iif;
oif = skb->dev->ifindex;
} else {
iif = skb->dev->ifindex;
oif = 0;
}
/* on ingress, the mac header gets popped, so push it back */
if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
skb_push(skb, skb->mac_len);
size = s->truncate ? s->trunc_size : skb->len;
psample_sample_packet(psample_group, skb, size, iif, oif,
s->rate);
if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
skb_pull(skb, skb->mac_len);
}
rcu_read_unlock();
return retval;
}
static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_sample *s = to_sample(a);
struct tc_sample opt = {
.index = s->tcf_index,
.action = s->tcf_action,
.refcnt = s->tcf_refcnt - ref,
.bindcnt = s->tcf_bindcnt - bind,
};
struct tcf_t t;
if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
tcf_tm_dump(&t, &s->tcf_tm);
if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
goto nla_put_failure;
if (s->truncate)
if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
goto nla_put_failure;
return skb->len;
nla_put_failure:
nlmsg_trim(skb, b);
return -1;
}
static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops)
{
struct tc_action_net *tn = net_generic(net, sample_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops);
}
static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, sample_net_id);
return tcf_idr_search(tn, a, index);
}
static struct tc_action_ops act_sample_ops = {
.kind = "sample",
.type = TCA_ACT_SAMPLE,
.owner = THIS_MODULE,
.act = tcf_sample_act,
.dump = tcf_sample_dump,
.init = tcf_sample_init,
.cleanup = tcf_sample_cleanup,
.walk = tcf_sample_walker,
.lookup = tcf_sample_search,
.size = sizeof(struct tcf_sample),
};
static __net_init int sample_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, sample_net_id);
return tc_action_net_init(tn, &act_sample_ops);
}
static void __net_exit sample_exit_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, sample_net_id);
tc_action_net_exit(tn);
}
static struct pernet_operations sample_net_ops = {
.init = sample_init_net,
.exit = sample_exit_net,
.id = &sample_net_id,
.size = sizeof(struct tc_action_net),
};
static int __init sample_init_module(void)
{
return tcf_register_action(&act_sample_ops, &sample_net_ops);
}
static void __exit sample_cleanup_module(void)
{
tcf_unregister_action(&act_sample_ops, &sample_net_ops);
}
module_init(sample_init_module);
module_exit(sample_cleanup_module);
MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
MODULE_DESCRIPTION("Packet sampling action");
MODULE_LICENSE("GPL v2");