1/*
2 * net/sched/ipt.c	iptables target interface
3 *
4 *TODO: Add other tables. For now we only support the ipv4 table targets
5 *
6 *		This program is free software; you can redistribute it and/or
7 *		modify it under the terms of the GNU General Public License
8 *		as published by the Free Software Foundation; either version
9 *		2 of the License, or (at your option) any later version.
10 *
11 * Copyright:	Jamal Hadi Salim (2002-4)
12 */
13
14#include <asm/uaccess.h>
15#include <asm/system.h>
16#include <asm/bitops.h>
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/socket.h>
22#include <linux/sockios.h>
23#include <linux/in.h>
24#include <linux/errno.h>
25#include <linux/interrupt.h>
26#include <linux/netdevice.h>
27#include <linux/skbuff.h>
28#include <linux/rtnetlink.h>
29#include <linux/module.h>
30#include <linux/init.h>
31#include <linux/proc_fs.h>
32#include <linux/kmod.h>
33#include <net/netlink.h>
34#include <net/sock.h>
35#include <net/pkt_sched.h>
36#include <linux/tc_act/tc_ipt.h>
37#include <net/tc_act/tc_ipt.h>
38
39#include <linux/netfilter_ipv4/ip_tables.h>
40
41
42#define IPT_TAB_MASK     15
43static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
44static u32 ipt_idx_gen;
45static DEFINE_RWLOCK(ipt_lock);
46
47static struct tcf_hashinfo ipt_hash_info = {
48	.htab	=	tcf_ipt_ht,
49	.hmask	=	IPT_TAB_MASK,
50	.lock	=	&ipt_lock,
51};
52
53static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
54{
55	struct xt_target *target;
56	int ret = 0;
57
58	target = xt_request_find_target(AF_INET, t->u.user.name,
59					t->u.user.revision);
60	if (!target)
61		return -ENOENT;
62
63	t->u.kernel.target = target;
64
65	ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
66			      table, hook, 0, 0);
67	if (ret) {
68		module_put(t->u.kernel.target->me);
69		return ret;
70	}
71	if (t->u.kernel.target->checkentry
72	    && !t->u.kernel.target->checkentry(table, NULL,
73					       t->u.kernel.target, t->data,
74					       hook)) {
75		module_put(t->u.kernel.target->me);
76		ret = -EINVAL;
77	}
78
79	return ret;
80}
81
82static void ipt_destroy_target(struct ipt_entry_target *t)
83{
84	if (t->u.kernel.target->destroy)
85		t->u.kernel.target->destroy(t->u.kernel.target, t->data);
86	module_put(t->u.kernel.target->me);
87}
88
89static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
90{
91	int ret = 0;
92	if (ipt) {
93		if (bind)
94			ipt->tcf_bindcnt--;
95		ipt->tcf_refcnt--;
96		if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
97			ipt_destroy_target(ipt->tcfi_t);
98			kfree(ipt->tcfi_tname);
99			kfree(ipt->tcfi_t);
100			tcf_hash_destroy(&ipt->common, &ipt_hash_info);
101			ret = ACT_P_DELETED;
102		}
103	}
104	return ret;
105}
106
107static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est,
108			struct tc_action *a, int ovr, int bind)
109{
110	struct rtattr *tb[TCA_IPT_MAX];
111	struct tcf_ipt *ipt;
112	struct tcf_common *pc;
113	struct ipt_entry_target *td, *t;
114	char *tname;
115	int ret = 0, err;
116	u32 hook = 0;
117	u32 index = 0;
118
119	if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0)
120		return -EINVAL;
121
122	if (tb[TCA_IPT_HOOK-1] == NULL ||
123	    RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32))
124		return -EINVAL;
125	if (tb[TCA_IPT_TARG-1] == NULL ||
126	    RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t))
127		return -EINVAL;
128	td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]);
129	if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size)
130		return -EINVAL;
131
132	if (tb[TCA_IPT_INDEX-1] != NULL &&
133	    RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32))
134		index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]);
135
136	pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
137	if (!pc) {
138		pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
139				     &ipt_idx_gen, &ipt_hash_info);
140		if (unlikely(!pc))
141			return -ENOMEM;
142		ret = ACT_P_CREATED;
143	} else {
144		if (!ovr) {
145			tcf_ipt_release(to_ipt(pc), bind);
146			return -EEXIST;
147		}
148	}
149	ipt = to_ipt(pc);
150
151	hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]);
152
153	err = -ENOMEM;
154	tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
155	if (unlikely(!tname))
156		goto err1;
157	if (tb[TCA_IPT_TABLE - 1] == NULL ||
158	    rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ)
159		strcpy(tname, "mangle");
160
161	t = kmemdup(td, td->u.target_size, GFP_KERNEL);
162	if (unlikely(!t))
163		goto err2;
164
165	if ((err = ipt_init_target(t, tname, hook)) < 0)
166		goto err3;
167
168	spin_lock_bh(&ipt->tcf_lock);
169	if (ret != ACT_P_CREATED) {
170		ipt_destroy_target(ipt->tcfi_t);
171		kfree(ipt->tcfi_tname);
172		kfree(ipt->tcfi_t);
173	}
174	ipt->tcfi_tname = tname;
175	ipt->tcfi_t     = t;
176	ipt->tcfi_hook  = hook;
177	spin_unlock_bh(&ipt->tcf_lock);
178	if (ret == ACT_P_CREATED)
179		tcf_hash_insert(pc, &ipt_hash_info);
180	return ret;
181
182err3:
183	kfree(t);
184err2:
185	kfree(tname);
186err1:
187	kfree(pc);
188	return err;
189}
190
191static int tcf_ipt_cleanup(struct tc_action *a, int bind)
192{
193	struct tcf_ipt *ipt = a->priv;
194	return tcf_ipt_release(ipt, bind);
195}
196
197static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
198		   struct tcf_result *res)
199{
200	int ret = 0, result = 0;
201	struct tcf_ipt *ipt = a->priv;
202
203	if (skb_cloned(skb)) {
204		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
205			return TC_ACT_UNSPEC;
206	}
207
208	spin_lock(&ipt->tcf_lock);
209
210	ipt->tcf_tm.lastuse = jiffies;
211	ipt->tcf_bstats.bytes += skb->len;
212	ipt->tcf_bstats.packets++;
213
214	/* yes, we have to worry about both in and out dev
215	 worry later - danger - this API seems to have changed
216	 from earlier kernels */
217
218	/* iptables targets take a double skb pointer in case the skb
219	 * needs to be replaced. We don't own the skb, so this must not
220	 * happen. The pskb_expand_head above should make sure of this */
221	ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL,
222						   ipt->tcfi_hook,
223						   ipt->tcfi_t->u.kernel.target,
224						   ipt->tcfi_t->data);
225	switch (ret) {
226	case NF_ACCEPT:
227		result = TC_ACT_OK;
228		break;
229	case NF_DROP:
230		result = TC_ACT_SHOT;
231		ipt->tcf_qstats.drops++;
232		break;
233	case IPT_CONTINUE:
234		result = TC_ACT_PIPE;
235		break;
236	default:
237		if (net_ratelimit())
238			printk("Bogus netfilter code %d assume ACCEPT\n", ret);
239		result = TC_POLICE_OK;
240		break;
241	}
242	spin_unlock(&ipt->tcf_lock);
243	return result;
244
245}
246
247static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
248{
249	unsigned char *b = skb_tail_pointer(skb);
250	struct tcf_ipt *ipt = a->priv;
251	struct ipt_entry_target *t;
252	struct tcf_t tm;
253	struct tc_cnt c;
254
255	/* for simple targets kernel size == user size
256	** user name = target name
257	** for foolproof you need to not assume this
258	*/
259
260	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
261	if (unlikely(!t))
262		goto rtattr_failure;
263
264	c.bindcnt = ipt->tcf_bindcnt - bind;
265	c.refcnt = ipt->tcf_refcnt - ref;
266	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
267
268	RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
269	RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index);
270	RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook);
271	RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
272	RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, ipt->tcfi_tname);
273	tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
274	tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
275	tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
276	RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
277	kfree(t);
278	return skb->len;
279
280rtattr_failure:
281	nlmsg_trim(skb, b);
282	kfree(t);
283	return -1;
284}
285
286static struct tc_action_ops act_ipt_ops = {
287	.kind		=	"ipt",
288	.hinfo		=	&ipt_hash_info,
289	.type		=	TCA_ACT_IPT,
290	.capab		=	TCA_CAP_NONE,
291	.owner		=	THIS_MODULE,
292	.act		=	tcf_ipt,
293	.dump		=	tcf_ipt_dump,
294	.cleanup	=	tcf_ipt_cleanup,
295	.lookup		=	tcf_hash_search,
296	.init		=	tcf_ipt_init,
297	.walk		=	tcf_generic_walker
298};
299
300MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
301MODULE_DESCRIPTION("Iptables target actions");
302MODULE_LICENSE("GPL");
303
304static int __init ipt_init_module(void)
305{
306	return tcf_register_action(&act_ipt_ops);
307}
308
309static void __exit ipt_cleanup_module(void)
310{
311	tcf_unregister_action(&act_ipt_ops);
312}
313
314module_init(ipt_init_module);
315module_exit(ipt_cleanup_module);
316