#include <linux/module.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/idr.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>
#include <net/tc_wrapper.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
MODULE_DESCRIPTION("TC BPF based classifier");
#define CLS_BPF_NAME_LEN 256
#define CLS_BPF_SUPPORTED_GEN_FLAGS \
(TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
struct cls_bpf_head {
struct list_head plist;
struct idr handle_idr;
struct rcu_head rcu;
};
struct cls_bpf_prog {
struct bpf_prog *filter;
struct list_head link;
struct tcf_result res;
bool exts_integrated;
u32 gen_flags;
unsigned int in_hw_count;
struct tcf_exts exts;
u32 handle;
u16 bpf_num_ops;
struct sock_filter *bpf_ops;
const char *bpf_name;
struct tcf_proto *tp;
struct rcu_work rwork;
};
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_FLAGS_GEN] = { .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_TRAP:
case TC_ACT_REDIRECT:
case TC_ACT_UNSPEC:
return code;
default:
return TC_ACT_UNSPEC;
}
}
TC_INDIRECT_SCOPE 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;
list_for_each_entry_rcu(prog, &head->plist, link) {
int filter_res;
qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
if (tc_skip_sw(prog->gen_flags)) {
filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
} else if (at_ingress) {
__skb_push(skb, skb->mac_len);
filter_res = bpf_prog_run_data_pointers(prog->filter, skb);
__skb_pull(skb, skb->mac_len);
} else {
filter_res = bpf_prog_run_data_pointers(prog->filter, skb);
}
if (unlikely(!skb->tstamp && skb->tstamp_type))
skb->tstamp_type = SKB_CLOCK_REALTIME;
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;
}
return ret;
}
static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
{
return !prog->bpf_ops;
}
static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
struct cls_bpf_prog *oldprog,
struct netlink_ext_ack *extack)
{
struct tcf_block *block = tp->chain->block;
struct tc_cls_bpf_offload cls_bpf = {};
struct cls_bpf_prog *obj;
bool skip_sw;
int err;
skip_sw = prog && tc_skip_sw(prog->gen_flags);
obj = prog ?: oldprog;
tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags, extack);
cls_bpf.command = TC_CLSBPF_OFFLOAD;
cls_bpf.exts = &obj->exts;
cls_bpf.prog = prog ? prog->filter : NULL;
cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
cls_bpf.name = obj->bpf_name;
cls_bpf.exts_integrated = obj->exts_integrated;
if (oldprog && prog)
err = tc_setup_cb_replace(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
skip_sw, &oldprog->gen_flags,
&oldprog->in_hw_count,
&prog->gen_flags, &prog->in_hw_count,
true);
else if (prog)
err = tc_setup_cb_add(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
skip_sw, &prog->gen_flags,
&prog->in_hw_count, true);
else
err = tc_setup_cb_destroy(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
skip_sw, &oldprog->gen_flags,
&oldprog->in_hw_count, true);
if (prog && err) {
cls_bpf_offload_cmd(tp, oldprog, prog, extack);
return err;
}
if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
return -EINVAL;
return 0;
}
static u32 cls_bpf_flags(u32 flags)
{
return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
}
static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
struct cls_bpf_prog *oldprog,
struct netlink_ext_ack *extack)
{
if (prog && oldprog &&
cls_bpf_flags(prog->gen_flags) !=
cls_bpf_flags(oldprog->gen_flags))
return -EINVAL;
if (prog && tc_skip_hw(prog->gen_flags))
prog = NULL;
if (oldprog && tc_skip_hw(oldprog->gen_flags))
oldprog = NULL;
if (!prog && !oldprog)
return 0;
return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
}
static void cls_bpf_stop_offload(struct tcf_proto *tp,
struct cls_bpf_prog *prog,
struct netlink_ext_ack *extack)
{
int err;
err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
if (err)
pr_err("Stopping hardware offload failed: %d\n", err);
}
static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
struct cls_bpf_prog *prog)
{
struct tcf_block *block = tp->chain->block;
struct tc_cls_bpf_offload cls_bpf = {};
tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
cls_bpf.command = TC_CLSBPF_STATS;
cls_bpf.exts = &prog->exts;
cls_bpf.prog = prog->filter;
cls_bpf.name = prog->bpf_name;
cls_bpf.exts_integrated = prog->exts_integrated;
tc_setup_cb_call(block, TC_SETUP_CLSBPF, &cls_bpf, false, true);
}
static int cls_bpf_init(struct tcf_proto *tp)
{
struct cls_bpf_head *head;
head = kzalloc_obj(*head);
if (head == NULL)
return -ENOBUFS;
INIT_LIST_HEAD_RCU(&head->plist);
idr_init(&head->handle_idr);
rcu_assign_pointer(tp->root, head);
return 0;
}
static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
{
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);
}
static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
{
tcf_exts_destroy(&prog->exts);
tcf_exts_put_net(&prog->exts);
cls_bpf_free_parms(prog);
kfree(prog);
}
static void cls_bpf_delete_prog_work(struct work_struct *work)
{
struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
struct cls_bpf_prog,
rwork);
rtnl_lock();
__cls_bpf_delete_prog(prog);
rtnl_unlock();
}
static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
struct netlink_ext_ack *extack)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
idr_remove(&head->handle_idr, prog->handle);
cls_bpf_stop_offload(tp, prog, extack);
list_del_rcu(&prog->link);
tcf_unbind_filter(tp, &prog->res);
if (tcf_exts_get_net(&prog->exts))
tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
else
__cls_bpf_delete_prog(prog);
}
static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
bool rtnl_held, struct netlink_ext_ack *extack)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
__cls_bpf_delete(tp, arg, extack);
*last = list_empty(&head->plist);
return 0;
}
static void cls_bpf_destroy(struct tcf_proto *tp, bool rtnl_held,
struct netlink_ext_ack *extack)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
struct cls_bpf_prog *prog, *tmp;
list_for_each_entry_safe(prog, tmp, &head->plist, link)
__cls_bpf_delete(tp, prog, extack);
idr_destroy(&head->handle_idr);
kfree_rcu(head, rcu);
}
static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
struct cls_bpf_prog *prog;
list_for_each_entry(prog, &head->plist, link) {
if (prog->handle == handle)
return prog;
}
return NULL;
}
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 = kmemdup(nla_data(tb[TCA_BPF_OPS]), bpf_size, GFP_KERNEL);
if (bpf_ops == NULL)
return -ENOMEM;
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,
u32 gen_flags, const struct tcf_proto *tp)
{
struct bpf_prog *fp;
char *name = NULL;
bool skip_sw;
u32 bpf_fd;
bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
if (IS_ERR(fp))
return PTR_ERR(fp);
if (tb[TCA_BPF_NAME]) {
name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
if (!name) {
bpf_prog_put(fp);
return -ENOMEM;
}
}
prog->bpf_ops = NULL;
prog->bpf_name = name;
prog->filter = fp;
if (fp->dst_needed)
tcf_block_netif_keep_dst(tp->chain->block);
return 0;
}
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,
void **arg, u32 flags,
struct netlink_ext_ack *extack)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
bool is_bpf, is_ebpf, have_exts = false;
struct cls_bpf_prog *oldprog = *arg;
struct nlattr *tb[TCA_BPF_MAX + 1];
bool bound_to_filter = false;
struct cls_bpf_prog *prog;
u32 gen_flags = 0;
int ret;
if (tca[TCA_OPTIONS] == NULL)
return -EINVAL;
ret = nla_parse_nested_deprecated(tb, TCA_BPF_MAX, tca[TCA_OPTIONS],
bpf_policy, NULL);
if (ret < 0)
return ret;
prog = kzalloc_obj(*prog);
if (!prog)
return -ENOBUFS;
ret = tcf_exts_init(&prog->exts, net, TCA_BPF_ACT, TCA_BPF_POLICE);
if (ret < 0)
goto errout;
if (oldprog) {
if (handle && oldprog->handle != handle) {
ret = -EINVAL;
goto errout;
}
}
if (handle == 0) {
handle = 1;
ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
INT_MAX, GFP_KERNEL);
} else if (!oldprog) {
ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
handle, GFP_KERNEL);
}
if (ret)
goto errout;
prog->handle = handle;
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)) {
ret = -EINVAL;
goto errout_idr;
}
ret = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &prog->exts,
flags, extack);
if (ret < 0)
goto errout_idr;
if (tb[TCA_BPF_FLAGS]) {
u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
ret = -EINVAL;
goto errout_idr;
}
have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
}
if (tb[TCA_BPF_FLAGS_GEN]) {
gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
!tc_flags_valid(gen_flags)) {
ret = -EINVAL;
goto errout_idr;
}
}
prog->exts_integrated = have_exts;
prog->gen_flags = gen_flags;
ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
if (ret < 0)
goto errout_idr;
if (tb[TCA_BPF_CLASSID]) {
prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
tcf_bind_filter(tp, &prog->res, base);
bound_to_filter = true;
}
ret = cls_bpf_offload(tp, prog, oldprog, extack);
if (ret)
goto errout_parms;
if (!tc_in_hw(prog->gen_flags))
prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
tcf_proto_update_usesw(tp, prog->gen_flags);
if (oldprog) {
idr_replace(&head->handle_idr, prog, handle);
list_replace_rcu(&oldprog->link, &prog->link);
tcf_unbind_filter(tp, &oldprog->res);
tcf_exts_get_net(&oldprog->exts);
tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
} else {
list_add_rcu(&prog->link, &head->plist);
}
*arg = prog;
return 0;
errout_parms:
if (bound_to_filter)
tcf_unbind_filter(tp, &prog->res);
cls_bpf_free_parms(prog);
errout_idr:
if (!oldprog)
idr_remove(&head->handle_idr, prog->handle);
errout:
tcf_exts_destroy(&prog->exts);
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)
{
struct nlattr *nla;
if (prog->bpf_name &&
nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
return -EMSGSIZE;
if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
return -EMSGSIZE;
nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
if (nla == NULL)
return -EMSGSIZE;
memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
return 0;
}
static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
struct sk_buff *skb, struct tcmsg *tm, bool rtnl_held)
{
struct cls_bpf_prog *prog = fh;
struct nlattr *nest;
u32 bpf_flags = 0;
int ret;
if (prog == NULL)
return skb->len;
tm->tcm_handle = prog->handle;
cls_bpf_offload_update_stats(tp, prog);
nest = nla_nest_start_noflag(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;
if (prog->gen_flags &&
nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_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_bind_class(void *fh, u32 classid, unsigned long cl,
void *q, unsigned long base)
{
struct cls_bpf_prog *prog = fh;
tc_cls_bind_class(classid, cl, q, &prog->res, base);
}
static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg,
bool rtnl_held)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
struct cls_bpf_prog *prog;
list_for_each_entry(prog, &head->plist, link) {
if (!tc_cls_stats_dump(tp, arg, prog))
break;
}
}
static int cls_bpf_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
void *cb_priv, struct netlink_ext_ack *extack)
{
struct cls_bpf_head *head = rtnl_dereference(tp->root);
struct tcf_block *block = tp->chain->block;
struct tc_cls_bpf_offload cls_bpf = {};
struct cls_bpf_prog *prog;
int err;
list_for_each_entry(prog, &head->plist, link) {
if (tc_skip_hw(prog->gen_flags))
continue;
tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags,
extack);
cls_bpf.command = TC_CLSBPF_OFFLOAD;
cls_bpf.exts = &prog->exts;
cls_bpf.prog = add ? prog->filter : NULL;
cls_bpf.oldprog = add ? NULL : prog->filter;
cls_bpf.name = prog->bpf_name;
cls_bpf.exts_integrated = prog->exts_integrated;
err = tc_setup_cb_reoffload(block, tp, add, cb, TC_SETUP_CLSBPF,
&cls_bpf, cb_priv, &prog->gen_flags,
&prog->in_hw_count);
if (err)
return err;
}
return 0;
}
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,
.reoffload = cls_bpf_reoffload,
.dump = cls_bpf_dump,
.bind_class = cls_bpf_bind_class,
};
MODULE_ALIAS_NET_CLS("bpf");
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);
