![Daniel Borkmann](/assets/img/avatar_default.png)
There are two issues with the current code. First one is that we need
to set res->class to 0 in case we use non-default classid matching.
This is important for the case where cls_bpf was initially set up with
an optional binding to a default class with tcf_bind_filter(), where
the underlying qdisc implements bind_tcf() that fills res->class and
tests for it later on when doing the classification. Convention for
these cases is that after tc_classify() was called, such qdiscs (atm,
drr, qfq, cbq, hfsc, htb) first test class, and if 0, then they lookup
based on classid.
Second, there's a bug with da mode, where res->classid is only assigned
a 16 bit minor, but it needs to expand to the full 32 bit major/minor
combination instead, therefore we need to expand with the bound major.
This is fine as classes belonging to a classful qdisc must share the
same major.
Fixes: 045efa82ff
("cls_bpf: introduce integrated actions")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
553 lines
12 KiB
C
553 lines
12 KiB
C
/*
|
|
* 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 <linux/bpf.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");
|
|
|
|
#define CLS_BPF_NAME_LEN 256
|
|
|
|
struct cls_bpf_head {
|
|
struct list_head plist;
|
|
u32 hgen;
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
struct cls_bpf_prog {
|
|
struct bpf_prog *filter;
|
|
struct list_head link;
|
|
struct tcf_result res;
|
|
bool exts_integrated;
|
|
struct tcf_exts exts;
|
|
u32 handle;
|
|
union {
|
|
u32 bpf_fd;
|
|
u16 bpf_num_ops;
|
|
};
|
|
struct sock_filter *bpf_ops;
|
|
const char *bpf_name;
|
|
struct tcf_proto *tp;
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
|
|
[TCA_BPF_CLASSID] = { .type = NLA_U32 },
|
|
[TCA_BPF_FLAGS] = { .type = NLA_U32 },
|
|
[TCA_BPF_FD] = { .type = NLA_U32 },
|
|
[TCA_BPF_NAME] = { .type = NLA_NUL_STRING, .len = CLS_BPF_NAME_LEN },
|
|
[TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
|
|
[TCA_BPF_OPS] = { .type = NLA_BINARY,
|
|
.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
|
|
};
|
|
|
|
static int cls_bpf_exec_opcode(int code)
|
|
{
|
|
switch (code) {
|
|
case TC_ACT_OK:
|
|
case TC_ACT_SHOT:
|
|
case TC_ACT_STOLEN:
|
|
case TC_ACT_REDIRECT:
|
|
case TC_ACT_UNSPEC:
|
|
return code;
|
|
default:
|
|
return TC_ACT_UNSPEC;
|
|
}
|
|
}
|
|
|
|
static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
|
|
struct tcf_result *res)
|
|
{
|
|
struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
|
|
bool at_ingress = skb_at_tc_ingress(skb);
|
|
struct cls_bpf_prog *prog;
|
|
int ret = -1;
|
|
|
|
if (unlikely(!skb_mac_header_was_set(skb)))
|
|
return -1;
|
|
|
|
/* Needed here for accessing maps. */
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(prog, &head->plist, link) {
|
|
int filter_res;
|
|
|
|
qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
|
|
|
|
if (at_ingress) {
|
|
/* It is safe to push/pull even if skb_shared() */
|
|
__skb_push(skb, skb->mac_len);
|
|
filter_res = BPF_PROG_RUN(prog->filter, skb);
|
|
__skb_pull(skb, skb->mac_len);
|
|
} else {
|
|
filter_res = BPF_PROG_RUN(prog->filter, skb);
|
|
}
|
|
|
|
if (prog->exts_integrated) {
|
|
res->class = 0;
|
|
res->classid = TC_H_MAJ(prog->res.classid) |
|
|
qdisc_skb_cb(skb)->tc_classid;
|
|
|
|
ret = cls_bpf_exec_opcode(filter_res);
|
|
if (ret == TC_ACT_UNSPEC)
|
|
continue;
|
|
break;
|
|
}
|
|
|
|
if (filter_res == 0)
|
|
continue;
|
|
if (filter_res != -1) {
|
|
res->class = 0;
|
|
res->classid = filter_res;
|
|
} else {
|
|
*res = prog->res;
|
|
}
|
|
|
|
ret = tcf_exts_exec(skb, &prog->exts, res);
|
|
if (ret < 0)
|
|
continue;
|
|
|
|
break;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
|
|
{
|
|
return !prog->bpf_ops;
|
|
}
|
|
|
|
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_RCU(&head->plist);
|
|
rcu_assign_pointer(tp->root, head);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
|
|
{
|
|
tcf_exts_destroy(&prog->exts);
|
|
|
|
if (cls_bpf_is_ebpf(prog))
|
|
bpf_prog_put(prog->filter);
|
|
else
|
|
bpf_prog_destroy(prog->filter);
|
|
|
|
kfree(prog->bpf_name);
|
|
kfree(prog->bpf_ops);
|
|
kfree(prog);
|
|
}
|
|
|
|
static void __cls_bpf_delete_prog(struct rcu_head *rcu)
|
|
{
|
|
struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
|
|
|
|
cls_bpf_delete_prog(prog->tp, prog);
|
|
}
|
|
|
|
static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
|
|
{
|
|
struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg;
|
|
|
|
list_del_rcu(&prog->link);
|
|
tcf_unbind_filter(tp, &prog->res);
|
|
call_rcu(&prog->rcu, __cls_bpf_delete_prog);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
|
|
{
|
|
struct cls_bpf_head *head = rtnl_dereference(tp->root);
|
|
struct cls_bpf_prog *prog, *tmp;
|
|
|
|
if (!force && !list_empty(&head->plist))
|
|
return false;
|
|
|
|
list_for_each_entry_safe(prog, tmp, &head->plist, link) {
|
|
list_del_rcu(&prog->link);
|
|
tcf_unbind_filter(tp, &prog->res);
|
|
call_rcu(&prog->rcu, __cls_bpf_delete_prog);
|
|
}
|
|
|
|
RCU_INIT_POINTER(tp->root, NULL);
|
|
kfree_rcu(head, rcu);
|
|
return true;
|
|
}
|
|
|
|
static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
|
|
{
|
|
struct cls_bpf_head *head = rtnl_dereference(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 int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
|
|
{
|
|
struct sock_filter *bpf_ops;
|
|
struct sock_fprog_kern fprog_tmp;
|
|
struct bpf_prog *fp;
|
|
u16 bpf_size, bpf_num_ops;
|
|
int ret;
|
|
|
|
bpf_num_ops = nla_get_u16(tb[TCA_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_BPF_OPS]))
|
|
return -EINVAL;
|
|
|
|
bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
|
|
if (bpf_ops == NULL)
|
|
return -ENOMEM;
|
|
|
|
memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
|
|
|
|
fprog_tmp.len = bpf_num_ops;
|
|
fprog_tmp.filter = bpf_ops;
|
|
|
|
ret = bpf_prog_create(&fp, &fprog_tmp);
|
|
if (ret < 0) {
|
|
kfree(bpf_ops);
|
|
return ret;
|
|
}
|
|
|
|
prog->bpf_ops = bpf_ops;
|
|
prog->bpf_num_ops = bpf_num_ops;
|
|
prog->bpf_name = NULL;
|
|
prog->filter = fp;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
|
|
const struct tcf_proto *tp)
|
|
{
|
|
struct bpf_prog *fp;
|
|
char *name = NULL;
|
|
u32 bpf_fd;
|
|
|
|
bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
|
|
|
|
fp = bpf_prog_get(bpf_fd);
|
|
if (IS_ERR(fp))
|
|
return PTR_ERR(fp);
|
|
|
|
if (fp->type != BPF_PROG_TYPE_SCHED_CLS) {
|
|
bpf_prog_put(fp);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (tb[TCA_BPF_NAME]) {
|
|
name = kmemdup(nla_data(tb[TCA_BPF_NAME]),
|
|
nla_len(tb[TCA_BPF_NAME]),
|
|
GFP_KERNEL);
|
|
if (!name) {
|
|
bpf_prog_put(fp);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
prog->bpf_ops = NULL;
|
|
prog->bpf_fd = bpf_fd;
|
|
prog->bpf_name = name;
|
|
prog->filter = fp;
|
|
|
|
if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
|
|
netif_keep_dst(qdisc_dev(tp->q));
|
|
|
|
return 0;
|
|
}
|
|
|
|
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)
|
|
{
|
|
bool is_bpf, is_ebpf, have_exts = false;
|
|
struct tcf_exts exts;
|
|
int ret;
|
|
|
|
is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
|
|
is_ebpf = tb[TCA_BPF_FD];
|
|
if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
|
|
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;
|
|
|
|
if (tb[TCA_BPF_FLAGS]) {
|
|
u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
|
|
|
|
if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
|
|
tcf_exts_destroy(&exts);
|
|
return -EINVAL;
|
|
}
|
|
|
|
have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
|
|
}
|
|
|
|
prog->exts_integrated = have_exts;
|
|
|
|
ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
|
|
cls_bpf_prog_from_efd(tb, prog, tp);
|
|
if (ret < 0) {
|
|
tcf_exts_destroy(&exts);
|
|
return ret;
|
|
}
|
|
|
|
if (tb[TCA_BPF_CLASSID]) {
|
|
prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
|
|
tcf_bind_filter(tp, &prog->res, base);
|
|
}
|
|
|
|
tcf_exts_change(tp, &prog->exts, &exts);
|
|
return 0;
|
|
}
|
|
|
|
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 = rtnl_dereference(tp->root);
|
|
struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
|
|
struct nlattr *tb[TCA_BPF_MAX + 1];
|
|
struct cls_bpf_prog *prog;
|
|
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;
|
|
|
|
prog = kzalloc(sizeof(*prog), GFP_KERNEL);
|
|
if (!prog)
|
|
return -ENOBUFS;
|
|
|
|
tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
|
|
|
|
if (oldprog) {
|
|
if (handle && oldprog->handle != handle) {
|
|
ret = -EINVAL;
|
|
goto errout;
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
if (oldprog) {
|
|
list_replace_rcu(&oldprog->link, &prog->link);
|
|
tcf_unbind_filter(tp, &oldprog->res);
|
|
call_rcu(&oldprog->rcu, __cls_bpf_delete_prog);
|
|
} else {
|
|
list_add_rcu(&prog->link, &head->plist);
|
|
}
|
|
|
|
*arg = (unsigned long) prog;
|
|
return 0;
|
|
errout:
|
|
kfree(prog);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct nlattr *nla;
|
|
|
|
if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
|
|
return -EMSGSIZE;
|
|
|
|
nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
|
|
sizeof(struct sock_filter));
|
|
if (nla == NULL)
|
|
return -EMSGSIZE;
|
|
|
|
memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
|
|
struct sk_buff *skb)
|
|
{
|
|
if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd))
|
|
return -EMSGSIZE;
|
|
|
|
if (prog->bpf_name &&
|
|
nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
|
|
return -EMSGSIZE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
u32 bpf_flags = 0;
|
|
int ret;
|
|
|
|
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 (prog->res.classid &&
|
|
nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
|
|
goto nla_put_failure;
|
|
|
|
if (cls_bpf_is_ebpf(prog))
|
|
ret = cls_bpf_dump_ebpf_info(prog, skb);
|
|
else
|
|
ret = cls_bpf_dump_bpf_info(prog, skb);
|
|
if (ret)
|
|
goto nla_put_failure;
|
|
|
|
if (tcf_exts_dump(skb, &prog->exts) < 0)
|
|
goto nla_put_failure;
|
|
|
|
if (prog->exts_integrated)
|
|
bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
|
|
if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
|
|
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 = rtnl_dereference(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,
|
|
.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);
|