xref: /openbmc/linux/net/sched/act_ipt.c (revision 52fb57e7)
1 /*
2  * net/sched/act_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 (2002-13)
12  */
13 
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/skbuff.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <net/netlink.h>
24 #include <net/pkt_sched.h>
25 #include <linux/tc_act/tc_ipt.h>
26 #include <net/tc_act/tc_ipt.h>
27 
28 #include <linux/netfilter_ipv4/ip_tables.h>
29 
30 
31 #define IPT_TAB_MASK     15
32 
33 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
34 {
35 	struct xt_tgchk_param par;
36 	struct xt_target *target;
37 	int ret = 0;
38 
39 	target = xt_request_find_target(AF_INET, t->u.user.name,
40 					t->u.user.revision);
41 	if (IS_ERR(target))
42 		return PTR_ERR(target);
43 
44 	t->u.kernel.target = target;
45 	par.table     = table;
46 	par.entryinfo = NULL;
47 	par.target    = target;
48 	par.targinfo  = t->data;
49 	par.hook_mask = hook;
50 	par.family    = NFPROTO_IPV4;
51 
52 	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
53 	if (ret < 0) {
54 		module_put(t->u.kernel.target->me);
55 		return ret;
56 	}
57 	return 0;
58 }
59 
60 static void ipt_destroy_target(struct xt_entry_target *t)
61 {
62 	struct xt_tgdtor_param par = {
63 		.target   = t->u.kernel.target,
64 		.targinfo = t->data,
65 	};
66 	if (par.target->destroy != NULL)
67 		par.target->destroy(&par);
68 	module_put(par.target->me);
69 }
70 
71 static void tcf_ipt_release(struct tc_action *a, int bind)
72 {
73 	struct tcf_ipt *ipt = to_ipt(a);
74 	ipt_destroy_target(ipt->tcfi_t);
75 	kfree(ipt->tcfi_tname);
76 	kfree(ipt->tcfi_t);
77 }
78 
79 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
80 	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
81 	[TCA_IPT_HOOK]	= { .type = NLA_U32 },
82 	[TCA_IPT_INDEX]	= { .type = NLA_U32 },
83 	[TCA_IPT_TARG]	= { .len = sizeof(struct xt_entry_target) },
84 };
85 
86 static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est,
87 			struct tc_action *a, int ovr, int bind)
88 {
89 	struct nlattr *tb[TCA_IPT_MAX + 1];
90 	struct tcf_ipt *ipt;
91 	struct xt_entry_target *td, *t;
92 	char *tname;
93 	int ret = 0, err;
94 	u32 hook = 0;
95 	u32 index = 0;
96 
97 	if (nla == NULL)
98 		return -EINVAL;
99 
100 	err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
101 	if (err < 0)
102 		return err;
103 
104 	if (tb[TCA_IPT_HOOK] == NULL)
105 		return -EINVAL;
106 	if (tb[TCA_IPT_TARG] == NULL)
107 		return -EINVAL;
108 
109 	td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
110 	if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
111 		return -EINVAL;
112 
113 	if (tb[TCA_IPT_INDEX] != NULL)
114 		index = nla_get_u32(tb[TCA_IPT_INDEX]);
115 
116 	if (!tcf_hash_check(index, a, bind) ) {
117 		ret = tcf_hash_create(index, est, a, sizeof(*ipt), bind);
118 		if (ret)
119 			return ret;
120 		ret = ACT_P_CREATED;
121 	} else {
122 		if (bind)/* dont override defaults */
123 			return 0;
124 		tcf_hash_release(a, bind);
125 
126 		if (!ovr)
127 			return -EEXIST;
128 	}
129 	ipt = to_ipt(a);
130 
131 	hook = nla_get_u32(tb[TCA_IPT_HOOK]);
132 
133 	err = -ENOMEM;
134 	tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
135 	if (unlikely(!tname))
136 		goto err1;
137 	if (tb[TCA_IPT_TABLE] == NULL ||
138 	    nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
139 		strcpy(tname, "mangle");
140 
141 	t = kmemdup(td, td->u.target_size, GFP_KERNEL);
142 	if (unlikely(!t))
143 		goto err2;
144 
145 	err = ipt_init_target(t, tname, hook);
146 	if (err < 0)
147 		goto err3;
148 
149 	spin_lock_bh(&ipt->tcf_lock);
150 	if (ret != ACT_P_CREATED) {
151 		ipt_destroy_target(ipt->tcfi_t);
152 		kfree(ipt->tcfi_tname);
153 		kfree(ipt->tcfi_t);
154 	}
155 	ipt->tcfi_tname = tname;
156 	ipt->tcfi_t     = t;
157 	ipt->tcfi_hook  = hook;
158 	spin_unlock_bh(&ipt->tcf_lock);
159 	if (ret == ACT_P_CREATED)
160 		tcf_hash_insert(a);
161 	return ret;
162 
163 err3:
164 	kfree(t);
165 err2:
166 	kfree(tname);
167 err1:
168 	if (ret == ACT_P_CREATED)
169 		tcf_hash_cleanup(a, est);
170 	return err;
171 }
172 
173 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
174 		   struct tcf_result *res)
175 {
176 	int ret = 0, result = 0;
177 	struct tcf_ipt *ipt = a->priv;
178 	struct xt_action_param par;
179 
180 	if (skb_unclone(skb, GFP_ATOMIC))
181 		return TC_ACT_UNSPEC;
182 
183 	spin_lock(&ipt->tcf_lock);
184 
185 	ipt->tcf_tm.lastuse = jiffies;
186 	bstats_update(&ipt->tcf_bstats, skb);
187 
188 	/* yes, we have to worry about both in and out dev
189 	 * worry later - danger - this API seems to have changed
190 	 * from earlier kernels
191 	 */
192 	par.in       = skb->dev;
193 	par.out      = NULL;
194 	par.hooknum  = ipt->tcfi_hook;
195 	par.target   = ipt->tcfi_t->u.kernel.target;
196 	par.targinfo = ipt->tcfi_t->data;
197 	ret = par.target->target(skb, &par);
198 
199 	switch (ret) {
200 	case NF_ACCEPT:
201 		result = TC_ACT_OK;
202 		break;
203 	case NF_DROP:
204 		result = TC_ACT_SHOT;
205 		ipt->tcf_qstats.drops++;
206 		break;
207 	case XT_CONTINUE:
208 		result = TC_ACT_PIPE;
209 		break;
210 	default:
211 		net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
212 				       ret);
213 		result = TC_POLICE_OK;
214 		break;
215 	}
216 	spin_unlock(&ipt->tcf_lock);
217 	return result;
218 
219 }
220 
221 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
222 {
223 	unsigned char *b = skb_tail_pointer(skb);
224 	struct tcf_ipt *ipt = a->priv;
225 	struct xt_entry_target *t;
226 	struct tcf_t tm;
227 	struct tc_cnt c;
228 
229 	/* for simple targets kernel size == user size
230 	 * user name = target name
231 	 * for foolproof you need to not assume this
232 	 */
233 
234 	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
235 	if (unlikely(!t))
236 		goto nla_put_failure;
237 
238 	c.bindcnt = ipt->tcf_bindcnt - bind;
239 	c.refcnt = ipt->tcf_refcnt - ref;
240 	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
241 
242 	if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
243 	    nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
244 	    nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
245 	    nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
246 	    nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
247 		goto nla_put_failure;
248 	tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
249 	tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
250 	tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
251 	if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
252 		goto nla_put_failure;
253 	kfree(t);
254 	return skb->len;
255 
256 nla_put_failure:
257 	nlmsg_trim(skb, b);
258 	kfree(t);
259 	return -1;
260 }
261 
262 static struct tc_action_ops act_ipt_ops = {
263 	.kind		=	"ipt",
264 	.type		=	TCA_ACT_IPT,
265 	.owner		=	THIS_MODULE,
266 	.act		=	tcf_ipt,
267 	.dump		=	tcf_ipt_dump,
268 	.cleanup	=	tcf_ipt_release,
269 	.init		=	tcf_ipt_init,
270 };
271 
272 static struct tc_action_ops act_xt_ops = {
273 	.kind		=	"xt",
274 	.type		=	TCA_ACT_XT,
275 	.owner		=	THIS_MODULE,
276 	.act		=	tcf_ipt,
277 	.dump		=	tcf_ipt_dump,
278 	.cleanup	=	tcf_ipt_release,
279 	.init		=	tcf_ipt_init,
280 };
281 
282 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
283 MODULE_DESCRIPTION("Iptables target actions");
284 MODULE_LICENSE("GPL");
285 MODULE_ALIAS("act_xt");
286 
287 static int __init ipt_init_module(void)
288 {
289 	int ret1, ret2;
290 
291 	ret1 = tcf_register_action(&act_xt_ops, IPT_TAB_MASK);
292 	if (ret1 < 0)
293 		printk("Failed to load xt action\n");
294 	ret2 = tcf_register_action(&act_ipt_ops, IPT_TAB_MASK);
295 	if (ret2 < 0)
296 		printk("Failed to load ipt action\n");
297 
298 	if (ret1 < 0 && ret2 < 0) {
299 		return ret1;
300 	} else
301 		return 0;
302 }
303 
304 static void __exit ipt_cleanup_module(void)
305 {
306 	tcf_unregister_action(&act_xt_ops);
307 	tcf_unregister_action(&act_ipt_ops);
308 }
309 
310 module_init(ipt_init_module);
311 module_exit(ipt_cleanup_module);
312