Commit d23b8ad8 authored by Jiri Pirko's avatar Jiri Pirko Committed by David S. Miller
Browse files

tc: add BPF based action



This action provides a possibility to exec custom BPF code.
Signed-off-by: default avatarJiri Pirko <jiri@resnulli.us>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02dba438
/*
* Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __NET_TC_BPF_H
#define __NET_TC_BPF_H
#include <linux/filter.h>
#include <net/act_api.h>
struct tcf_bpf {
struct tcf_common common;
struct bpf_prog *filter;
struct sock_filter *bpf_ops;
u16 bpf_num_ops;
};
#define to_bpf(a) \
container_of(a->priv, struct tcf_bpf, common)
#endif /* __NET_TC_BPF_H */
......@@ -8,3 +8,4 @@ header-y += tc_nat.h
header-y += tc_pedit.h
header-y += tc_skbedit.h
header-y += tc_vlan.h
header-y += tc_bpf.h
/*
* Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __LINUX_TC_BPF_H
#define __LINUX_TC_BPF_H
#include <linux/pkt_cls.h>
#define TCA_ACT_BPF 13
struct tc_act_bpf {
tc_gen;
};
enum {
TCA_ACT_BPF_UNSPEC,
TCA_ACT_BPF_TM,
TCA_ACT_BPF_PARMS,
TCA_ACT_BPF_OPS_LEN,
TCA_ACT_BPF_OPS,
__TCA_ACT_BPF_MAX,
};
#define TCA_ACT_BPF_MAX (__TCA_ACT_BPF_MAX - 1)
#endif
......@@ -698,6 +698,18 @@ config NET_ACT_VLAN
To compile this code as a module, choose M here: the
module will be called act_vlan.
config NET_ACT_BPF
tristate "BPF based action"
depends on NET_CLS_ACT
---help---
Say Y here to execute BPF code on packets. The BPF code will decide
if the packet should be dropped or not.
If unsure, say N.
To compile this code as a module, choose M here: the
module will be called act_bpf.
config NET_CLS_IND
bool "Incoming device classification"
depends on NET_CLS_U32 || NET_CLS_FW
......
......@@ -17,6 +17,7 @@ obj-$(CONFIG_NET_ACT_SIMP) += act_simple.o
obj-$(CONFIG_NET_ACT_SKBEDIT) += act_skbedit.o
obj-$(CONFIG_NET_ACT_CSUM) += act_csum.o
obj-$(CONFIG_NET_ACT_VLAN) += act_vlan.o
obj-$(CONFIG_NET_ACT_BPF) += act_bpf.o
obj-$(CONFIG_NET_SCH_FIFO) += sch_fifo.o
obj-$(CONFIG_NET_SCH_CBQ) += sch_cbq.o
obj-$(CONFIG_NET_SCH_HTB) += sch_htb.o
......
/*
* Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/filter.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_bpf.h>
#include <net/tc_act/tc_bpf.h>
#define BPF_TAB_MASK 15
static int tcf_bpf(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_bpf *b = a->priv;
int action;
int filter_res;
spin_lock(&b->tcf_lock);
b->tcf_tm.lastuse = jiffies;
bstats_update(&b->tcf_bstats, skb);
action = b->tcf_action;
filter_res = BPF_PROG_RUN(b->filter, skb);
if (filter_res == 0) {
/* Return code 0 from the BPF program
* is being interpreted as a drop here.
*/
action = TC_ACT_SHOT;
b->tcf_qstats.drops++;
}
spin_unlock(&b->tcf_lock);
return action;
}
static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *tp = skb_tail_pointer(skb);
struct tcf_bpf *b = a->priv;
struct tc_act_bpf opt = {
.index = b->tcf_index,
.refcnt = b->tcf_refcnt - ref,
.bindcnt = b->tcf_bindcnt - bind,
.action = b->tcf_action,
};
struct tcf_t t;
struct nlattr *nla;
if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops))
goto nla_put_failure;
nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops *
sizeof(struct sock_filter));
if (!nla)
goto nla_put_failure;
memcpy(nla_data(nla), b->bpf_ops, nla_len(nla));
t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install);
t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse);
t.expires = jiffies_to_clock_t(b->tcf_tm.expires);
if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t))
goto nla_put_failure;
return skb->len;
nla_put_failure:
nlmsg_trim(skb, tp);
return -1;
}
static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
[TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
[TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
[TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
};
static int tcf_bpf_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action *a,
int ovr, int bind)
{
struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
struct tc_act_bpf *parm;
struct tcf_bpf *b;
u16 bpf_size, bpf_num_ops;
struct sock_filter *bpf_ops;
struct sock_fprog_kern tmp;
struct bpf_prog *fp;
int ret;
if (!nla)
return -EINVAL;
ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
if (ret < 0)
return ret;
if (!tb[TCA_ACT_BPF_PARMS] ||
!tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS])
return -EINVAL;
parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
return -EINVAL;
bpf_size = bpf_num_ops * sizeof(*bpf_ops);
bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
if (!bpf_ops)
return -ENOMEM;
memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
tmp.len = bpf_num_ops;
tmp.filter = bpf_ops;
ret = bpf_prog_create(&fp, &tmp);
if (ret)
goto free_bpf_ops;
if (!tcf_hash_check(parm->index, a, bind)) {
ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind);
if (ret)
goto destroy_fp;
ret = ACT_P_CREATED;
} else {
if (bind)
goto destroy_fp;
tcf_hash_release(a, bind);
if (!ovr) {
ret = -EEXIST;
goto destroy_fp;
}
}
b = to_bpf(a);
spin_lock_bh(&b->tcf_lock);
b->tcf_action = parm->action;
b->bpf_num_ops = bpf_num_ops;
b->bpf_ops = bpf_ops;
b->filter = fp;
spin_unlock_bh(&b->tcf_lock);
if (ret == ACT_P_CREATED)
tcf_hash_insert(a);
return ret;
destroy_fp:
bpf_prog_destroy(fp);
free_bpf_ops:
kfree(bpf_ops);
return ret;
}
static void tcf_bpf_cleanup(struct tc_action *a, int bind)
{
struct tcf_bpf *b = a->priv;
bpf_prog_destroy(b->filter);
}
static struct tc_action_ops act_bpf_ops = {
.kind = "bpf",
.type = TCA_ACT_BPF,
.owner = THIS_MODULE,
.act = tcf_bpf,
.dump = tcf_bpf_dump,
.cleanup = tcf_bpf_cleanup,
.init = tcf_bpf_init,
};
static int __init bpf_init_module(void)
{
return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK);
}
static void __exit bpf_cleanup_module(void)
{
tcf_unregister_action(&act_bpf_ops);
}
module_init(bpf_init_module);
module_exit(bpf_cleanup_module);
MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
MODULE_DESCRIPTION("TC BPF based action");
MODULE_LICENSE("GPL v2");
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