blob: d2f034cf60558ffd3b3de9faf92fea2bb79247da [file] [log] [blame]
/*
* Berkeley Packet Filter based traffic classifier
*
* Might be used to classify traffic through flexible, user-defined and
* possibly JIT-ed BPF filters for traffic control as an alternative to
* ematches.
*
* (C) 2013 Daniel Borkmann <dborkman@redhat.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/module.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
MODULE_DESCRIPTION("TC BPF based classifier");
struct cls_bpf_head {
struct list_head plist;
u32 hgen;
};
struct cls_bpf_prog {
struct sk_filter *filter;
struct sock_filter *bpf_ops;
struct tcf_exts exts;
struct tcf_result res;
struct list_head link;
u32 handle;
u16 bpf_len;
};
static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
[TCA_BPF_CLASSID] = { .type = NLA_U32 },
[TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
[TCA_BPF_OPS] = { .type = NLA_BINARY,
.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
};
static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog;
int ret;
list_for_each_entry(prog, &head->plist, link) {
int filter_res = SK_RUN_FILTER(prog->filter, skb);
if (filter_res == 0)
continue;
*res = prog->res;
if (filter_res != -1)
res->classid = filter_res;
ret = tcf_exts_exec(skb, &prog->exts, res);
if (ret < 0)
continue;
return ret;
}
return -1;
}
static int cls_bpf_init(struct tcf_proto *tp)
{
struct cls_bpf_head *head;
head = kzalloc(sizeof(*head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
INIT_LIST_HEAD(&head->plist);
tp->root = head;
return 0;
}
static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
{
tcf_unbind_filter(tp, &prog->res);
tcf_exts_destroy(tp, &prog->exts);
sk_unattached_filter_destroy(prog->filter);
kfree(prog->bpf_ops);
kfree(prog);
}
static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog, *todel = (struct cls_bpf_prog *) arg;
list_for_each_entry(prog, &head->plist, link) {
if (prog == todel) {
tcf_tree_lock(tp);
list_del(&prog->link);
tcf_tree_unlock(tp);
cls_bpf_delete_prog(tp, prog);
return 0;
}
}
return -ENOENT;
}
static void cls_bpf_destroy(struct tcf_proto *tp)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog, *tmp;
list_for_each_entry_safe(prog, tmp, &head->plist, link) {
list_del(&prog->link);
cls_bpf_delete_prog(tp, prog);
}
kfree(head);
}
static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog;
unsigned long ret = 0UL;
if (head == NULL)
return 0UL;
list_for_each_entry(prog, &head->plist, link) {
if (prog->handle == handle) {
ret = (unsigned long) prog;
break;
}
}
return ret;
}
static void cls_bpf_put(struct tcf_proto *tp, unsigned long f)
{
}
static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
struct cls_bpf_prog *prog,
unsigned long base, struct nlattr **tb,
struct nlattr *est, bool ovr)
{
struct sock_filter *bpf_ops, *bpf_old;
struct tcf_exts exts;
struct sock_fprog_kern tmp;
struct sk_filter *fp, *fp_old;
u16 bpf_size, bpf_len;
u32 classid;
int ret;
if (!tb[TCA_BPF_OPS_LEN] || !tb[TCA_BPF_OPS] || !tb[TCA_BPF_CLASSID])
return -EINVAL;
tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
if (ret < 0)
return ret;
classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
bpf_len = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
if (bpf_len > BPF_MAXINSNS || bpf_len == 0) {
ret = -EINVAL;
goto errout;
}
bpf_size = bpf_len * sizeof(*bpf_ops);
if (bpf_size != nla_len(tb[TCA_BPF_OPS])) {
ret = -EINVAL;
goto errout;
}
bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
if (bpf_ops == NULL) {
ret = -ENOMEM;
goto errout;
}
memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
tmp.len = bpf_len;
tmp.filter = bpf_ops;
ret = sk_unattached_filter_create(&fp, &tmp);
if (ret)
goto errout_free;
tcf_tree_lock(tp);
fp_old = prog->filter;
bpf_old = prog->bpf_ops;
prog->bpf_len = bpf_len;
prog->bpf_ops = bpf_ops;
prog->filter = fp;
prog->res.classid = classid;
tcf_tree_unlock(tp);
tcf_bind_filter(tp, &prog->res, base);
tcf_exts_change(tp, &prog->exts, &exts);
if (fp_old)
sk_unattached_filter_destroy(fp_old);
if (bpf_old)
kfree(bpf_old);
return 0;
errout_free:
kfree(bpf_ops);
errout:
tcf_exts_destroy(tp, &exts);
return ret;
}
static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
struct cls_bpf_head *head)
{
unsigned int i = 0x80000000;
u32 handle;
do {
if (++head->hgen == 0x7FFFFFFF)
head->hgen = 1;
} while (--i > 0 && cls_bpf_get(tp, head->hgen));
if (unlikely(i == 0)) {
pr_err("Insufficient number of handles\n");
handle = 0;
} else {
handle = head->hgen;
}
return handle;
}
static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base,
u32 handle, struct nlattr **tca,
unsigned long *arg, bool ovr)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog = (struct cls_bpf_prog *) *arg;
struct nlattr *tb[TCA_BPF_MAX + 1];
int ret;
if (tca[TCA_OPTIONS] == NULL)
return -EINVAL;
ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy);
if (ret < 0)
return ret;
if (prog != NULL) {
if (handle && prog->handle != handle)
return -EINVAL;
return cls_bpf_modify_existing(net, tp, prog, base, tb,
tca[TCA_RATE], ovr);
}
prog = kzalloc(sizeof(*prog), GFP_KERNEL);
if (prog == NULL)
return -ENOBUFS;
tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
if (handle == 0)
prog->handle = cls_bpf_grab_new_handle(tp, head);
else
prog->handle = handle;
if (prog->handle == 0) {
ret = -EINVAL;
goto errout;
}
ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
if (ret < 0)
goto errout;
tcf_tree_lock(tp);
list_add(&prog->link, &head->plist);
tcf_tree_unlock(tp);
*arg = (unsigned long) prog;
return 0;
errout:
if (*arg == 0UL && prog)
kfree(prog);
return ret;
}
static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *tm)
{
struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
struct nlattr *nest, *nla;
if (prog == NULL)
return skb->len;
tm->tcm_handle = prog->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
goto nla_put_failure;
if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_len))
goto nla_put_failure;
nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_len *
sizeof(struct sock_filter));
if (nla == NULL)
goto nla_put_failure;
memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
if (tcf_exts_dump(skb, &prog->exts) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest);
if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct cls_bpf_head *head = tp->root;
struct cls_bpf_prog *prog;
list_for_each_entry(prog, &head->plist, link) {
if (arg->count < arg->skip)
goto skip;
if (arg->fn(tp, (unsigned long) prog, arg) < 0) {
arg->stop = 1;
break;
}
skip:
arg->count++;
}
}
static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
.kind = "bpf",
.owner = THIS_MODULE,
.classify = cls_bpf_classify,
.init = cls_bpf_init,
.destroy = cls_bpf_destroy,
.get = cls_bpf_get,
.put = cls_bpf_put,
.change = cls_bpf_change,
.delete = cls_bpf_delete,
.walk = cls_bpf_walk,
.dump = cls_bpf_dump,
};
static int __init cls_bpf_init_mod(void)
{
return register_tcf_proto_ops(&cls_bpf_ops);
}
static void __exit cls_bpf_exit_mod(void)
{
unregister_tcf_proto_ops(&cls_bpf_ops);
}
module_init(cls_bpf_init_mod);
module_exit(cls_bpf_exit_mod);