net/sched/cls_bpf.c - kernel/lockdown - Git at Google

 /*
  * 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;
 	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_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_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 			    struct tcf_result *res)
 {
 	struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
 	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 = BPF_PROG_RUN(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;

 		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, u32 classid)
 {
 	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;
 	prog->res.classid = classid;

 	return 0;
 }

 static int cls_bpf_prog_from_efd(struct nlattr **tb,
 				 struct cls_bpf_prog *prog, u32 classid)
 {
 	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;
 	prog->res.classid = classid;

 	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)
 {
 	struct tcf_exts exts;
 	bool is_bpf, is_ebpf;
 	u32 classid;
 	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) ||
 	    !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]);

 	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) :
 		       cls_bpf_prog_from_efd(tb, prog, classid);
 	if (ret < 0) {
 		tcf_exts_destroy(&exts);
 		return ret;
 	}

 	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;
 	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 (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;

 	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);
	/*
	* 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;
	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_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_classify(struct sk_buff skb, const struct tcf_proto tp,
	struct tcf_result *res)
	{
	struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
	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 = BPF_PROG_RUN(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;

	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, u32 classid)
	{
	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;
	prog->res.classid = classid;

	return 0;
	}

	static int cls_bpf_prog_from_efd(struct nlattr **tb,
	struct cls_bpf_prog *prog, u32 classid)
	{
	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;
	prog->res.classid = classid;

	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)
	{
	struct tcf_exts exts;
	bool is_bpf, is_ebpf;
	u32 classid;
	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) \|\|
	!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]);

	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) :
	cls_bpf_prog_from_efd(tb, prog, classid);
	if (ret < 0) {
	tcf_exts_destroy(&exts);
	return ret;
	}

	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;
	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 (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;

	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);