Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 725 insertions, 0 deletions

diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
new file mode 100644
index 000000000..55bf75cb1
--- /dev/null
+++ b/net/sched/cls_flow.c
@@ -0,0 +1,725 @@
+/*
+ * net/sched/cls_flow.c		Generic flow classifier
+ *
+ * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/jhash.h>
+#include <linux/random.h>
+#include <linux/pkt_cls.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/if_vlan.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <net/inet_sock.h>
+
+#include <net/pkt_cls.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/flow_dissector.h>
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#include <net/netfilter/nf_conntrack.h>
+#endif
+
+struct flow_head {
+	struct list_head	filters;
+	struct rcu_head		rcu;
+};
+
+struct flow_filter {
+	struct list_head	list;
+	struct tcf_exts		exts;
+	struct tcf_ematch_tree	ematches;
+	struct tcf_proto	*tp;
+	struct timer_list	perturb_timer;
+	u32			perturb_period;
+	u32			handle;
+
+	u32			nkeys;
+	u32			keymask;
+	u32			mode;
+	u32			mask;
+	u32			xor;
+	u32			rshift;
+	u32			addend;
+	u32			divisor;
+	u32			baseclass;
+	u32			hashrnd;
+	struct rcu_work		rwork;
+};
+
+static inline u32 addr_fold(void *addr)
+{
+	unsigned long a = (unsigned long)addr;
+
+	return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
+}
+
+static u32 flow_get_src(const struct sk_buff *skb, const struct flow_keys *flow)
+{
+	__be32 src = flow_get_u32_src(flow);
+
+	if (src)
+		return ntohl(src);
+
+	return addr_fold(skb->sk);
+}
+
+static u32 flow_get_dst(const struct sk_buff *skb, const struct flow_keys *flow)
+{
+	__be32 dst = flow_get_u32_dst(flow);
+
+	if (dst)
+		return ntohl(dst);
+
+	return addr_fold(skb_dst(skb)) ^ (__force u16)skb_protocol(skb, true);
+}
+
+static u32 flow_get_proto(const struct sk_buff *skb,
+			  const struct flow_keys *flow)
+{
+	return flow->basic.ip_proto;
+}
+
+static u32 flow_get_proto_src(const struct sk_buff *skb,
+			      const struct flow_keys *flow)
+{
+	if (flow->ports.ports)
+		return ntohs(flow->ports.src);
+
+	return addr_fold(skb->sk);
+}
+
+static u32 flow_get_proto_dst(const struct sk_buff *skb,
+			      const struct flow_keys *flow)
+{
+	if (flow->ports.ports)
+		return ntohs(flow->ports.dst);
+
+	return addr_fold(skb_dst(skb)) ^ (__force u16)skb_protocol(skb, true);
+}
+
+static u32 flow_get_iif(const struct sk_buff *skb)
+{
+	return skb->skb_iif;
+}
+
+static u32 flow_get_priority(const struct sk_buff *skb)
+{
+	return skb->priority;
+}
+
+static u32 flow_get_mark(const struct sk_buff *skb)
+{
+	return skb->mark;
+}
+
+static u32 flow_get_nfct(const struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+	return addr_fold(skb_nfct(skb));
+#else
+	return 0;
+#endif
+}
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#define CTTUPLE(skb, member)						\
+({									\
+	enum ip_conntrack_info ctinfo;					\
+	const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);		\
+	if (ct == NULL)							\
+		goto fallback;						\
+	ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;			\
+})
+#else
+#define CTTUPLE(skb, member)						\
+({									\
+	goto fallback;							\
+	0;								\
+})
+#endif
+
+static u32 flow_get_nfct_src(const struct sk_buff *skb,
+			     const struct flow_keys *flow)
+{
+	switch (skb_protocol(skb, true)) {
+	case htons(ETH_P_IP):
+		return ntohl(CTTUPLE(skb, src.u3.ip));
+	case htons(ETH_P_IPV6):
+		return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
+	}
+fallback:
+	return flow_get_src(skb, flow);
+}
+
+static u32 flow_get_nfct_dst(const struct sk_buff *skb,
+			     const struct flow_keys *flow)
+{
+	switch (skb_protocol(skb, true)) {
+	case htons(ETH_P_IP):
+		return ntohl(CTTUPLE(skb, dst.u3.ip));
+	case htons(ETH_P_IPV6):
+		return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
+	}
+fallback:
+	return flow_get_dst(skb, flow);
+}
+
+static u32 flow_get_nfct_proto_src(const struct sk_buff *skb,
+				   const struct flow_keys *flow)
+{
+	return ntohs(CTTUPLE(skb, src.u.all));
+fallback:
+	return flow_get_proto_src(skb, flow);
+}
+
+static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb,
+				   const struct flow_keys *flow)
+{
+	return ntohs(CTTUPLE(skb, dst.u.all));
+fallback:
+	return flow_get_proto_dst(skb, flow);
+}
+
+static u32 flow_get_rtclassid(const struct sk_buff *skb)
+{
+#ifdef CONFIG_IP_ROUTE_CLASSID
+	if (skb_dst(skb))
+		return skb_dst(skb)->tclassid;
+#endif
+	return 0;
+}
+
+static u32 flow_get_skuid(const struct sk_buff *skb)
+{
+	struct sock *sk = skb_to_full_sk(skb);
+
+	if (sk && sk->sk_socket && sk->sk_socket->file) {
+		kuid_t skuid = sk->sk_socket->file->f_cred->fsuid;
+
+		return from_kuid(&init_user_ns, skuid);
+	}
+	return 0;
+}
+
+static u32 flow_get_skgid(const struct sk_buff *skb)
+{
+	struct sock *sk = skb_to_full_sk(skb);
+
+	if (sk && sk->sk_socket && sk->sk_socket->file) {
+		kgid_t skgid = sk->sk_socket->file->f_cred->fsgid;
+
+		return from_kgid(&init_user_ns, skgid);
+	}
+	return 0;
+}
+
+static u32 flow_get_vlan_tag(const struct sk_buff *skb)
+{
+	u16 uninitialized_var(tag);
+
+	if (vlan_get_tag(skb, &tag) < 0)
+		return 0;
+	return tag & VLAN_VID_MASK;
+}
+
+static u32 flow_get_rxhash(struct sk_buff *skb)
+{
+	return skb_get_hash(skb);
+}
+
+static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow)
+{
+	switch (key) {
+	case FLOW_KEY_SRC:
+		return flow_get_src(skb, flow);
+	case FLOW_KEY_DST:
+		return flow_get_dst(skb, flow);
+	case FLOW_KEY_PROTO:
+		return flow_get_proto(skb, flow);
+	case FLOW_KEY_PROTO_SRC:
+		return flow_get_proto_src(skb, flow);
+	case FLOW_KEY_PROTO_DST:
+		return flow_get_proto_dst(skb, flow);
+	case FLOW_KEY_IIF:
+		return flow_get_iif(skb);
+	case FLOW_KEY_PRIORITY:
+		return flow_get_priority(skb);
+	case FLOW_KEY_MARK:
+		return flow_get_mark(skb);
+	case FLOW_KEY_NFCT:
+		return flow_get_nfct(skb);
+	case FLOW_KEY_NFCT_SRC:
+		return flow_get_nfct_src(skb, flow);
+	case FLOW_KEY_NFCT_DST:
+		return flow_get_nfct_dst(skb, flow);
+	case FLOW_KEY_NFCT_PROTO_SRC:
+		return flow_get_nfct_proto_src(skb, flow);
+	case FLOW_KEY_NFCT_PROTO_DST:
+		return flow_get_nfct_proto_dst(skb, flow);
+	case FLOW_KEY_RTCLASSID:
+		return flow_get_rtclassid(skb);
+	case FLOW_KEY_SKUID:
+		return flow_get_skuid(skb);
+	case FLOW_KEY_SKGID:
+		return flow_get_skgid(skb);
+	case FLOW_KEY_VLAN_TAG:
+		return flow_get_vlan_tag(skb);
+	case FLOW_KEY_RXHASH:
+		return flow_get_rxhash(skb);
+	default:
+		WARN_ON(1);
+		return 0;
+	}
+}
+
+#define FLOW_KEYS_NEEDED ((1 << FLOW_KEY_SRC) | 		\
+			  (1 << FLOW_KEY_DST) |			\
+			  (1 << FLOW_KEY_PROTO) |		\
+			  (1 << FLOW_KEY_PROTO_SRC) |		\
+			  (1 << FLOW_KEY_PROTO_DST) | 		\
+			  (1 << FLOW_KEY_NFCT_SRC) |		\
+			  (1 << FLOW_KEY_NFCT_DST) |		\
+			  (1 << FLOW_KEY_NFCT_PROTO_SRC) |	\
+			  (1 << FLOW_KEY_NFCT_PROTO_DST))
+
+static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+			 struct tcf_result *res)
+{
+	struct flow_head *head = rcu_dereference_bh(tp->root);
+	struct flow_filter *f;
+	u32 keymask;
+	u32 classid;
+	unsigned int n, key;
+	int r;
+
+	list_for_each_entry_rcu(f, &head->filters, list) {
+		u32 keys[FLOW_KEY_MAX + 1];
+		struct flow_keys flow_keys;
+
+		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
+			continue;
+
+		keymask = f->keymask;
+		if (keymask & FLOW_KEYS_NEEDED)
+			skb_flow_dissect_flow_keys(skb, &flow_keys, 0);
+
+		for (n = 0; n < f->nkeys; n++) {
+			key = ffs(keymask) - 1;
+			keymask &= ~(1 << key);
+			keys[n] = flow_key_get(skb, key, &flow_keys);
+		}
+
+		if (f->mode == FLOW_MODE_HASH)
+			classid = jhash2(keys, f->nkeys, f->hashrnd);
+		else {
+			classid = keys[0];
+			classid = (classid & f->mask) ^ f->xor;
+			classid = (classid >> f->rshift) + f->addend;
+		}
+
+		if (f->divisor)
+			classid %= f->divisor;
+
+		res->class   = 0;
+		res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
+
+		r = tcf_exts_exec(skb, &f->exts, res);
+		if (r < 0)
+			continue;
+		return r;
+	}
+	return -1;
+}
+
+static void flow_perturbation(struct timer_list *t)
+{
+	struct flow_filter *f = from_timer(f, t, perturb_timer);
+
+	get_random_bytes(&f->hashrnd, 4);
+	if (f->perturb_period)
+		mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
+}
+
+static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
+	[TCA_FLOW_KEYS]		= { .type = NLA_U32 },
+	[TCA_FLOW_MODE]		= { .type = NLA_U32 },
+	[TCA_FLOW_BASECLASS]	= { .type = NLA_U32 },
+	[TCA_FLOW_RSHIFT]	= { .type = NLA_U32 },
+	[TCA_FLOW_ADDEND]	= { .type = NLA_U32 },
+	[TCA_FLOW_MASK]		= { .type = NLA_U32 },
+	[TCA_FLOW_XOR]		= { .type = NLA_U32 },
+	[TCA_FLOW_DIVISOR]	= { .type = NLA_U32 },
+	[TCA_FLOW_ACT]		= { .type = NLA_NESTED },
+	[TCA_FLOW_POLICE]	= { .type = NLA_NESTED },
+	[TCA_FLOW_EMATCHES]	= { .type = NLA_NESTED },
+	[TCA_FLOW_PERTURB]	= { .type = NLA_U32 },
+};
+
+static void __flow_destroy_filter(struct flow_filter *f)
+{
+	del_timer_sync(&f->perturb_timer);
+	tcf_exts_destroy(&f->exts);
+	tcf_em_tree_destroy(&f->ematches);
+	tcf_exts_put_net(&f->exts);
+	kfree(f);
+}
+
+static void flow_destroy_filter_work(struct work_struct *work)
+{
+	struct flow_filter *f = container_of(to_rcu_work(work),
+					     struct flow_filter,
+					     rwork);
+	rtnl_lock();
+	__flow_destroy_filter(f);
+	rtnl_unlock();
+}
+
+static int flow_change(struct net *net, struct sk_buff *in_skb,
+		       struct tcf_proto *tp, unsigned long base,
+		       u32 handle, struct nlattr **tca,
+		       void **arg, bool ovr, struct netlink_ext_ack *extack)
+{
+	struct flow_head *head = rtnl_dereference(tp->root);
+	struct flow_filter *fold, *fnew;
+	struct nlattr *opt = tca[TCA_OPTIONS];
+	struct nlattr *tb[TCA_FLOW_MAX + 1];
+	unsigned int nkeys = 0;
+	unsigned int perturb_period = 0;
+	u32 baseclass = 0;
+	u32 keymask = 0;
+	u32 mode;
+	int err;
+
+	if (opt == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy, NULL);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_FLOW_BASECLASS]) {
+		baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
+		if (TC_H_MIN(baseclass) == 0)
+			return -EINVAL;
+	}
+
+	if (tb[TCA_FLOW_KEYS]) {
+		keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
+
+		nkeys = hweight32(keymask);
+		if (nkeys == 0)
+			return -EINVAL;
+
+		if (fls(keymask) - 1 > FLOW_KEY_MAX)
+			return -EOPNOTSUPP;
+
+		if ((keymask & (FLOW_KEY_SKUID|FLOW_KEY_SKGID)) &&
+		    sk_user_ns(NETLINK_CB(in_skb).sk) != &init_user_ns)
+			return -EOPNOTSUPP;
+	}
+
+	fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
+	if (!fnew)
+		return -ENOBUFS;
+
+	err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &fnew->ematches);
+	if (err < 0)
+		goto err1;
+
+	err = tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE);
+	if (err < 0)
+		goto err2;
+
+	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &fnew->exts, ovr,
+				extack);
+	if (err < 0)
+		goto err2;
+
+	fold = *arg;
+	if (fold) {
+		err = -EINVAL;
+		if (fold->handle != handle && handle)
+			goto err2;
+
+		/* Copy fold into fnew */
+		fnew->tp = fold->tp;
+		fnew->handle = fold->handle;
+		fnew->nkeys = fold->nkeys;
+		fnew->keymask = fold->keymask;
+		fnew->mode = fold->mode;
+		fnew->mask = fold->mask;
+		fnew->xor = fold->xor;
+		fnew->rshift = fold->rshift;
+		fnew->addend = fold->addend;
+		fnew->divisor = fold->divisor;
+		fnew->baseclass = fold->baseclass;
+		fnew->hashrnd = fold->hashrnd;
+
+		mode = fold->mode;
+		if (tb[TCA_FLOW_MODE])
+			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
+		if (mode != FLOW_MODE_HASH && nkeys > 1)
+			goto err2;
+
+		if (mode == FLOW_MODE_HASH)
+			perturb_period = fold->perturb_period;
+		if (tb[TCA_FLOW_PERTURB]) {
+			if (mode != FLOW_MODE_HASH)
+				goto err2;
+			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
+		}
+	} else {
+		err = -EINVAL;
+		if (!handle)
+			goto err2;
+		if (!tb[TCA_FLOW_KEYS])
+			goto err2;
+
+		mode = FLOW_MODE_MAP;
+		if (tb[TCA_FLOW_MODE])
+			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
+		if (mode != FLOW_MODE_HASH && nkeys > 1)
+			goto err2;
+
+		if (tb[TCA_FLOW_PERTURB]) {
+			if (mode != FLOW_MODE_HASH)
+				goto err2;
+			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
+		}
+
+		if (TC_H_MAJ(baseclass) == 0) {
+			struct Qdisc *q = tcf_block_q(tp->chain->block);
+
+			baseclass = TC_H_MAKE(q->handle, baseclass);
+		}
+		if (TC_H_MIN(baseclass) == 0)
+			baseclass = TC_H_MAKE(baseclass, 1);
+
+		fnew->handle = handle;
+		fnew->mask  = ~0U;
+		fnew->tp = tp;
+		get_random_bytes(&fnew->hashrnd, 4);
+	}
+
+	timer_setup(&fnew->perturb_timer, flow_perturbation, TIMER_DEFERRABLE);
+
+	tcf_block_netif_keep_dst(tp->chain->block);
+
+	if (tb[TCA_FLOW_KEYS]) {
+		fnew->keymask = keymask;
+		fnew->nkeys   = nkeys;
+	}
+
+	fnew->mode = mode;
+
+	if (tb[TCA_FLOW_MASK])
+		fnew->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
+	if (tb[TCA_FLOW_XOR])
+		fnew->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
+	if (tb[TCA_FLOW_RSHIFT])
+		fnew->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
+	if (tb[TCA_FLOW_ADDEND])
+		fnew->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
+
+	if (tb[TCA_FLOW_DIVISOR])
+		fnew->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
+	if (baseclass)
+		fnew->baseclass = baseclass;
+
+	fnew->perturb_period = perturb_period;
+	if (perturb_period)
+		mod_timer(&fnew->perturb_timer, jiffies + perturb_period);
+
+	if (!*arg)
+		list_add_tail_rcu(&fnew->list, &head->filters);
+	else
+		list_replace_rcu(&fold->list, &fnew->list);
+
+	*arg = fnew;
+
+	if (fold) {
+		tcf_exts_get_net(&fold->exts);
+		tcf_queue_work(&fold->rwork, flow_destroy_filter_work);
+	}
+	return 0;
+
+err2:
+	tcf_exts_destroy(&fnew->exts);
+	tcf_em_tree_destroy(&fnew->ematches);
+err1:
+	kfree(fnew);
+	return err;
+}
+
+static int flow_delete(struct tcf_proto *tp, void *arg, bool *last,
+		       struct netlink_ext_ack *extack)
+{
+	struct flow_head *head = rtnl_dereference(tp->root);
+	struct flow_filter *f = arg;
+
+	list_del_rcu(&f->list);
+	tcf_exts_get_net(&f->exts);
+	tcf_queue_work(&f->rwork, flow_destroy_filter_work);
+	*last = list_empty(&head->filters);
+	return 0;
+}
+
+static int flow_init(struct tcf_proto *tp)
+{
+	struct flow_head *head;
+
+	head = kzalloc(sizeof(*head), GFP_KERNEL);
+	if (head == NULL)
+		return -ENOBUFS;
+	INIT_LIST_HEAD(&head->filters);
+	rcu_assign_pointer(tp->root, head);
+	return 0;
+}
+
+static void flow_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
+{
+	struct flow_head *head = rtnl_dereference(tp->root);
+	struct flow_filter *f, *next;
+
+	list_for_each_entry_safe(f, next, &head->filters, list) {
+		list_del_rcu(&f->list);
+		if (tcf_exts_get_net(&f->exts))
+			tcf_queue_work(&f->rwork, flow_destroy_filter_work);
+		else
+			__flow_destroy_filter(f);
+	}
+	kfree_rcu(head, rcu);
+}
+
+static void *flow_get(struct tcf_proto *tp, u32 handle)
+{
+	struct flow_head *head = rtnl_dereference(tp->root);
+	struct flow_filter *f;
+
+	list_for_each_entry(f, &head->filters, list)
+		if (f->handle == handle)
+			return f;
+	return NULL;
+}
+
+static int flow_dump(struct net *net, struct tcf_proto *tp, void *fh,
+		     struct sk_buff *skb, struct tcmsg *t)
+{
+	struct flow_filter *f = fh;
+	struct nlattr *nest;
+
+	if (f == NULL)
+		return skb->len;
+
+	t->tcm_handle = f->handle;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, TCA_FLOW_KEYS, f->keymask) ||
+	    nla_put_u32(skb, TCA_FLOW_MODE, f->mode))
+		goto nla_put_failure;
+
+	if (f->mask != ~0 || f->xor != 0) {
+		if (nla_put_u32(skb, TCA_FLOW_MASK, f->mask) ||
+		    nla_put_u32(skb, TCA_FLOW_XOR, f->xor))
+			goto nla_put_failure;
+	}
+	if (f->rshift &&
+	    nla_put_u32(skb, TCA_FLOW_RSHIFT, f->rshift))
+		goto nla_put_failure;
+	if (f->addend &&
+	    nla_put_u32(skb, TCA_FLOW_ADDEND, f->addend))
+		goto nla_put_failure;
+
+	if (f->divisor &&
+	    nla_put_u32(skb, TCA_FLOW_DIVISOR, f->divisor))
+		goto nla_put_failure;
+	if (f->baseclass &&
+	    nla_put_u32(skb, TCA_FLOW_BASECLASS, f->baseclass))
+		goto nla_put_failure;
+
+	if (f->perturb_period &&
+	    nla_put_u32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ))
+		goto nla_put_failure;
+
+	if (tcf_exts_dump(skb, &f->exts) < 0)
+		goto nla_put_failure;
+#ifdef CONFIG_NET_EMATCH
+	if (f->ematches.hdr.nmatches &&
+	    tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
+		goto nla_put_failure;
+#endif
+	nla_nest_end(skb, nest);
+
+	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
+		goto nla_put_failure;
+
+	return skb->len;
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -1;
+}
+
+static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
+{
+	struct flow_head *head = rtnl_dereference(tp->root);
+	struct flow_filter *f;
+
+	list_for_each_entry(f, &head->filters, list) {
+		if (arg->count < arg->skip)
+			goto skip;
+		if (arg->fn(tp, f, arg) < 0) {
+			arg->stop = 1;
+			break;
+		}
+skip:
+		arg->count++;
+	}
+}
+
+static struct tcf_proto_ops cls_flow_ops __read_mostly = {
+	.kind		= "flow",
+	.classify	= flow_classify,
+	.init		= flow_init,
+	.destroy	= flow_destroy,
+	.change		= flow_change,
+	.delete		= flow_delete,
+	.get		= flow_get,
+	.dump		= flow_dump,
+	.walk		= flow_walk,
+	.owner		= THIS_MODULE,
+};
+
+static int __init cls_flow_init(void)
+{
+	return register_tcf_proto_ops(&cls_flow_ops);
+}
+
+static void __exit cls_flow_exit(void)
+{
+	unregister_tcf_proto_ops(&cls_flow_ops);
+}
+
+module_init(cls_flow_init);
+module_exit(cls_flow_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("TC flow classifier");