net/sched: Retire ipt action

The tc ipt action was intended to run all netfilter/iptables target.
Unfortunately it has not benefitted over the years from proper updates when
netfilter changes, and for that reason it has remained rudimentary.
Pinging a bunch of people that i was aware were using this indicates that
removing it wont affect them.
Retire it to reduce maintenance efforts. Buh-bye.

Reviewed-by: Victor Noguiera <[e-mail]>
Reviewed-by: Pedro Tammela <[e-mail]>
Signed-off-by: Jamal Hadi Salim <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/tc_act/tc_ipt.h

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __NET_TC_IPT_H
-#define __NET_TC_IPT_H
-
-#include <net/act_api.h>
-
-struct xt_entry_target;
-
-struct tcf_ipt {
-	struct tc_action	common;
-	u32			tcfi_hook;
-	char			*tcfi_tname;
-	struct xt_entry_target	*tcfi_t;
-};
-#define to_ipt(a) ((struct tcf_ipt *)a)
-
-#endif /* __NET_TC_IPT_H */

include/net/tc_wrapper.h

···
 	if (a->ops->act == tcf_ife_act)
 		return tcf_ife_act(skb, a, res);
 #endif
-#if IS_BUILTIN(CONFIG_NET_ACT_IPT)
-	if (a->ops->act == tcf_ipt_act)
-		return tcf_ipt_act(skb, a, res);
-#endif
 #if IS_BUILTIN(CONFIG_NET_ACT_SIMP)
 	if (a->ops->act == tcf_simp_act)
 		return tcf_simp_act(skb, a, res);

include/uapi/linux/pkt_cls.h

···
  * versions.
  */
 #define TCA_ACT_GACT 5
-#define TCA_ACT_IPT 6
+#define TCA_ACT_IPT 6 /* obsoleted, can be reused */
 #define TCA_ACT_PEDIT 7
 #define TCA_ACT_MIRRED 8
 #define TCA_ACT_NAT 9
···
 	TCA_ID_UNSPEC = 0,
 	TCA_ID_POLICE = 1,
 	TCA_ID_GACT = TCA_ACT_GACT,
-	TCA_ID_IPT = TCA_ACT_IPT,
+	TCA_ID_IPT = TCA_ACT_IPT, /* Obsoleted, can be reused */
 	TCA_ID_PEDIT = TCA_ACT_PEDIT,
 	TCA_ID_MIRRED = TCA_ACT_MIRRED,
 	TCA_ID_NAT = TCA_ACT_NAT,

include/uapi/linux/tc_act/tc_ipt.h

···
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef __LINUX_TC_IPT_H
-#define __LINUX_TC_IPT_H
-
-#include <linux/pkt_cls.h>
-
-enum {
-	TCA_IPT_UNSPEC,
-	TCA_IPT_TABLE,
-	TCA_IPT_HOOK,
-	TCA_IPT_INDEX,
-	TCA_IPT_CNT,
-	TCA_IPT_TM,
-	TCA_IPT_TARG,
-	TCA_IPT_PAD,
-	__TCA_IPT_MAX
-};
-#define TCA_IPT_MAX (__TCA_IPT_MAX - 1)
-                                                                                
-#endif

net/sched/Makefile

···
 obj-$(CONFIG_NET_ACT_GACT)	+= act_gact.o
 obj-$(CONFIG_NET_ACT_MIRRED)	+= act_mirred.o
 obj-$(CONFIG_NET_ACT_SAMPLE)	+= act_sample.o
-obj-$(CONFIG_NET_ACT_IPT)	+= act_ipt.o
 obj-$(CONFIG_NET_ACT_NAT)	+= act_nat.o
 obj-$(CONFIG_NET_ACT_PEDIT)	+= act_pedit.o
 obj-$(CONFIG_NET_ACT_SIMP)	+= act_simple.o

net/sched/act_ipt.c

···
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * net/sched/act_ipt.c		iptables target interface
- *
- *TODO: Add other tables. For now we only support the ipv4 table targets
- *
- * Copyright:	Jamal Hadi Salim (2002-13)
- */
-
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/string.h>
-#include <linux/errno.h>
-#include <linux/skbuff.h>
-#include <linux/rtnetlink.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <net/netlink.h>
-#include <net/pkt_sched.h>
-#include <linux/tc_act/tc_ipt.h>
-#include <net/tc_act/tc_ipt.h>
-#include <net/tc_wrapper.h>
-#include <net/ip.h>
-
-#include <linux/netfilter_ipv4/ip_tables.h>
-
-
-static struct tc_action_ops act_ipt_ops;
-static struct tc_action_ops act_xt_ops;
-
-static int ipt_init_target(struct net *net, struct xt_entry_target *t,
-			   char *table, unsigned int hook)
-{
-	struct xt_tgchk_param par;
-	struct xt_target *target;
-	struct ipt_entry e = {};
-	int ret = 0;
-
-	target = xt_request_find_target(AF_INET, t->u.user.name,
-					t->u.user.revision);
-	if (IS_ERR(target))
-		return PTR_ERR(target);
-
-	t->u.kernel.target = target;
-	memset(&par, 0, sizeof(par));
-	par.net       = net;
-	par.table     = table;
-	par.entryinfo = &e;
-	par.target    = target;
-	par.targinfo  = t->data;
-	par.hook_mask = 1 << hook;
-	par.family    = NFPROTO_IPV4;
-
-	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
-	if (ret < 0) {
-		module_put(t->u.kernel.target->me);
-		return ret;
-	}
-	return 0;
-}
-
-static void ipt_destroy_target(struct xt_entry_target *t, struct net *net)
-{
-	struct xt_tgdtor_param par = {
-		.target   = t->u.kernel.target,
-		.targinfo = t->data,
-		.family   = NFPROTO_IPV4,
-		.net      = net,
-	};
-	if (par.target->destroy != NULL)
-		par.target->destroy(&par);
-	module_put(par.target->me);
-}
-
-static void tcf_ipt_release(struct tc_action *a)
-{
-	struct tcf_ipt *ipt = to_ipt(a);
-
-	if (ipt->tcfi_t) {
-		ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
-		kfree(ipt->tcfi_t);
-	}
-	kfree(ipt->tcfi_tname);
-}
-
-static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
-	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
-	[TCA_IPT_HOOK]	= NLA_POLICY_RANGE(NLA_U32, NF_INET_PRE_ROUTING,
-					   NF_INET_NUMHOOKS),
-	[TCA_IPT_INDEX]	= { .type = NLA_U32 },
-	[TCA_IPT_TARG]	= { .len = sizeof(struct xt_entry_target) },
-};
-
-static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
-			  struct nlattr *est, struct tc_action **a,
-			  const struct tc_action_ops *ops,
-			  struct tcf_proto *tp, u32 flags)
-{
-	struct tc_action_net *tn = net_generic(net, id);
-	bool bind = flags & TCA_ACT_FLAGS_BIND;
-	struct nlattr *tb[TCA_IPT_MAX + 1];
-	struct tcf_ipt *ipt;
-	struct xt_entry_target *td, *t;
-	char *tname;
-	bool exists = false;
-	int ret = 0, err;
-	u32 hook = 0;
-	u32 index = 0;
-
-	if (nla == NULL)
-		return -EINVAL;
-
-	err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy,
-					  NULL);
-	if (err < 0)
-		return err;
-
-	if (tb[TCA_IPT_INDEX] != NULL)
-		index = nla_get_u32(tb[TCA_IPT_INDEX]);
-
-	err = tcf_idr_check_alloc(tn, &index, a, bind);
-	if (err < 0)
-		return err;
-	exists = err;
-	if (exists && bind)
-		return 0;
-
-	if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
-		if (exists)
-			tcf_idr_release(*a, bind);
-		else
-			tcf_idr_cleanup(tn, index);
-		return -EINVAL;
-	}
-
-	td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
-	if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) {
-		if (exists)
-			tcf_idr_release(*a, bind);
-		else
-			tcf_idr_cleanup(tn, index);
-		return -EINVAL;
-	}
-
-	if (!exists) {
-		ret = tcf_idr_create(tn, index, est, a, ops, bind,
-				     false, flags);
-		if (ret) {
-			tcf_idr_cleanup(tn, index);
-			return ret;
-		}
-		ret = ACT_P_CREATED;
-	} else {
-		if (bind)/* dont override defaults */
-			return 0;
-
-		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
-			tcf_idr_release(*a, bind);
-			return -EEXIST;
-		}
-	}
-
-	err = -EINVAL;
-	hook = nla_get_u32(tb[TCA_IPT_HOOK]);
-	switch (hook) {
-	case NF_INET_PRE_ROUTING:
-		break;
-	case NF_INET_POST_ROUTING:
-		break;
-	default:
-		goto err1;
-	}
-
-	if (tb[TCA_IPT_TABLE]) {
-		/* mangle only for now */
-		if (nla_strcmp(tb[TCA_IPT_TABLE], "mangle"))
-			goto err1;
-	}
-
-	tname = kstrdup("mangle", GFP_KERNEL);
-	if (unlikely(!tname))
-		goto err1;
-
-	t = kmemdup(td, td->u.target_size, GFP_KERNEL);
-	if (unlikely(!t))
-		goto err2;
-
-	err = ipt_init_target(net, t, tname, hook);
-	if (err < 0)
-		goto err3;
-
-	ipt = to_ipt(*a);
-
-	spin_lock_bh(&ipt->tcf_lock);
-	if (ret != ACT_P_CREATED) {
-		ipt_destroy_target(ipt->tcfi_t, net);
-		kfree(ipt->tcfi_tname);
-		kfree(ipt->tcfi_t);
-	}
-	ipt->tcfi_tname = tname;
-	ipt->tcfi_t     = t;
-	ipt->tcfi_hook  = hook;
-	spin_unlock_bh(&ipt->tcf_lock);
-	return ret;
-
-err3:
-	kfree(t);
-err2:
-	kfree(tname);
-err1:
-	tcf_idr_release(*a, bind);
-	return err;
-}
-
-static int tcf_ipt_init(struct net *net, struct nlattr *nla,
-			struct nlattr *est, struct tc_action **a,
-			struct tcf_proto *tp,
-			u32 flags, struct netlink_ext_ack *extack)
-{
-	return __tcf_ipt_init(net, act_ipt_ops.net_id, nla, est,
-			      a, &act_ipt_ops, tp, flags);
-}
-
-static int tcf_xt_init(struct net *net, struct nlattr *nla,
-		       struct nlattr *est, struct tc_action **a,
-		       struct tcf_proto *tp,
-		       u32 flags, struct netlink_ext_ack *extack)
-{
-	return __tcf_ipt_init(net, act_xt_ops.net_id, nla, est,
-			      a, &act_xt_ops, tp, flags);
-}
-
-static bool tcf_ipt_act_check(struct sk_buff *skb)
-{
-	const struct iphdr *iph;
-	unsigned int nhoff, len;
-
-	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
-		return false;
-
-	nhoff = skb_network_offset(skb);
-	iph = ip_hdr(skb);
-	if (iph->ihl < 5 || iph->version != 4)
-		return false;
-
-	len = skb_ip_totlen(skb);
-	if (skb->len < nhoff + len || len < (iph->ihl * 4u))
-		return false;
-
-	return pskb_may_pull(skb, iph->ihl * 4u);
-}
-
-TC_INDIRECT_SCOPE int tcf_ipt_act(struct sk_buff *skb,
-				  const struct tc_action *a,
-				  struct tcf_result *res)
-{
-	char saved_cb[sizeof_field(struct sk_buff, cb)];
-	int ret = 0, result = 0;
-	struct tcf_ipt *ipt = to_ipt(a);
-	struct xt_action_param par;
-	struct nf_hook_state state = {
-		.net	= dev_net(skb->dev),
-		.in	= skb->dev,
-		.hook	= ipt->tcfi_hook,
-		.pf	= NFPROTO_IPV4,
-	};
-
-	if (skb_protocol(skb, false) != htons(ETH_P_IP))
-		return TC_ACT_UNSPEC;
-
-	if (skb_unclone(skb, GFP_ATOMIC))
-		return TC_ACT_UNSPEC;
-
-	if (!tcf_ipt_act_check(skb))
-		return TC_ACT_UNSPEC;
-
-	if (state.hook == NF_INET_POST_ROUTING) {
-		if (!skb_dst(skb))
-			return TC_ACT_UNSPEC;
-
-		state.out = skb->dev;
-	}
-
-	memcpy(saved_cb, skb->cb, sizeof(saved_cb));
-
-	spin_lock(&ipt->tcf_lock);
-
-	tcf_lastuse_update(&ipt->tcf_tm);
-	bstats_update(&ipt->tcf_bstats, skb);
-
-	/* yes, we have to worry about both in and out dev
-	 * worry later - danger - this API seems to have changed
-	 * from earlier kernels
-	 */
-	par.state    = &state;
-	par.target   = ipt->tcfi_t->u.kernel.target;
-	par.targinfo = ipt->tcfi_t->data;
-
-	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
-
-	ret = par.target->target(skb, &par);
-
-	switch (ret) {
-	case NF_ACCEPT:
-		result = TC_ACT_OK;
-		break;
-	case NF_DROP:
-		result = TC_ACT_SHOT;
-		ipt->tcf_qstats.drops++;
-		break;
-	case XT_CONTINUE:
-		result = TC_ACT_PIPE;
-		break;
-	default:
-		net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
-				       ret);
-		result = TC_ACT_OK;
-		break;
-	}
-	spin_unlock(&ipt->tcf_lock);
-
-	memcpy(skb->cb, saved_cb, sizeof(skb->cb));
-
-	return result;
-
-}
-
-static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
-			int ref)
-{
-	unsigned char *b = skb_tail_pointer(skb);
-	struct tcf_ipt *ipt = to_ipt(a);
-	struct xt_entry_target *t;
-	struct tcf_t tm;
-	struct tc_cnt c;
-
-	/* for simple targets kernel size == user size
-	 * user name = target name
-	 * for foolproof you need to not assume this
-	 */
-
-	spin_lock_bh(&ipt->tcf_lock);
-	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
-	if (unlikely(!t))
-		goto nla_put_failure;
-
-	c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
-	c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
-	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
-
-	if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
-	    nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
-	    nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
-	    nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
-	    nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
-		goto nla_put_failure;
-
-	tcf_tm_dump(&tm, &ipt->tcf_tm);
-	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
-		goto nla_put_failure;
-
-	spin_unlock_bh(&ipt->tcf_lock);
-	kfree(t);
-	return skb->len;
-
-nla_put_failure:
-	spin_unlock_bh(&ipt->tcf_lock);
-	nlmsg_trim(skb, b);
-	kfree(t);
-	return -1;
-}
-
-static struct tc_action_ops act_ipt_ops = {
-	.kind		=	"ipt",
-	.id		=	TCA_ID_IPT,
-	.owner		=	THIS_MODULE,
-	.act		=	tcf_ipt_act,
-	.dump		=	tcf_ipt_dump,
-	.cleanup	=	tcf_ipt_release,
-	.init		=	tcf_ipt_init,
-	.size		=	sizeof(struct tcf_ipt),
-};
-
-static __net_init int ipt_init_net(struct net *net)
-{
-	struct tc_action_net *tn = net_generic(net, act_ipt_ops.net_id);
-
-	return tc_action_net_init(net, tn, &act_ipt_ops);
-}
-
-static void __net_exit ipt_exit_net(struct list_head *net_list)
-{
-	tc_action_net_exit(net_list, act_ipt_ops.net_id);
-}
-
-static struct pernet_operations ipt_net_ops = {
-	.init = ipt_init_net,
-	.exit_batch = ipt_exit_net,
-	.id   = &act_ipt_ops.net_id,
-	.size = sizeof(struct tc_action_net),
-};
-
-static struct tc_action_ops act_xt_ops = {
-	.kind		=	"xt",
-	.id		=	TCA_ID_XT,
-	.owner		=	THIS_MODULE,
-	.act		=	tcf_ipt_act,
-	.dump		=	tcf_ipt_dump,
-	.cleanup	=	tcf_ipt_release,
-	.init		=	tcf_xt_init,
-	.size		=	sizeof(struct tcf_ipt),
-};
-
-static __net_init int xt_init_net(struct net *net)
-{
-	struct tc_action_net *tn = net_generic(net, act_xt_ops.net_id);
-
-	return tc_action_net_init(net, tn, &act_xt_ops);
-}
-
-static void __net_exit xt_exit_net(struct list_head *net_list)
-{
-	tc_action_net_exit(net_list, act_xt_ops.net_id);
-}
-
-static struct pernet_operations xt_net_ops = {
-	.init = xt_init_net,
-	.exit_batch = xt_exit_net,
-	.id   = &act_xt_ops.net_id,
-	.size = sizeof(struct tc_action_net),
-};
-
-MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
-MODULE_DESCRIPTION("Iptables target actions");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("act_xt");
-
-static int __init ipt_init_module(void)
-{
-	int ret1, ret2;
-
-	ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
-	if (ret1 < 0)
-		pr_err("Failed to load xt action\n");
-
-	ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
-	if (ret2 < 0)
-		pr_err("Failed to load ipt action\n");
-
-	if (ret1 < 0 && ret2 < 0) {
-		return ret1;
-	} else
-		return 0;
-}
-
-static void __exit ipt_cleanup_module(void)
-{
-	tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
-	tcf_unregister_action(&act_xt_ops, &xt_net_ops);
-}
-
-module_init(ipt_init_module);
-module_exit(ipt_cleanup_module);

tools/testing/selftests/tc-testing/config

···
 CONFIG_GACT_PROB=y
 CONFIG_NET_ACT_MIRRED=m
 CONFIG_NET_ACT_SAMPLE=m
-CONFIG_NET_ACT_IPT=m
 CONFIG_NET_ACT_NAT=m
 CONFIG_NET_ACT_PEDIT=m
 CONFIG_NET_ACT_SIMP=m

tools/testing/selftests/tc-testing/tdc.sh

···
 try_modprobe act_ctinfo
 try_modprobe act_gact
 try_modprobe act_gate
-try_modprobe act_ipt
 try_modprobe act_mirred
 try_modprobe act_mpls
 try_modprobe act_nat