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/*
* 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, filter_res;
spin_lock(&b->tcf_lock);
b->tcf_tm.lastuse = jiffies;
bstats_update(&b->tcf_bstats, skb);
filter_res = BPF_PROG_RUN(b->filter, skb);
/* A BPF program may overwrite the default action opcode.
* Similarly as in cls_bpf, if filter_res == -1 we use the
* default action specified from tc.
*
* In case a different well-known TC_ACT opcode has been
* returned, it will overwrite the default one.
*
* For everything else that is unkown, TC_ACT_UNSPEC is
* returned.
*/
switch (filter_res) {
case TC_ACT_PIPE:
case TC_ACT_RECLASSIFY:
case TC_ACT_OK:
action = filter_res;
break;
case TC_ACT_SHOT:
action = filter_res;
b->tcf_qstats.drops++;
break;
case TC_ACT_UNSPEC:
action = b->tcf_action;
break;
default:
action = TC_ACT_UNSPEC;
break;
}
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);
if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
return -EINVAL;
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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