xref: /linux/net/sched/act_pedit.c (revision 02000b55850deeadffe433e4b4930a8831f477de) 
1 /*
2  * net/sched/act_pedit.c	Generic packet editor
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Jamal Hadi Salim (2002-4)
10  */
11 
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/skbuff.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23 #include <linux/tc_act/tc_pedit.h>
24 #include <net/tc_act/tc_pedit.h>
25 #include <uapi/linux/tc_act/tc_pedit.h>
26 
27 static unsigned int pedit_net_id;
28 static struct tc_action_ops act_pedit_ops;
29 
30 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
31 	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
32 	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
33 };
34 
35 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
36 	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
37 	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
38 };
39 
40 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
41 							u8 n)
42 {
43 	struct tcf_pedit_key_ex *keys_ex;
44 	struct tcf_pedit_key_ex *k;
45 	const struct nlattr *ka;
46 	int err = -EINVAL;
47 	int rem;
48 
49 	if (!nla || !n)
50 		return NULL;
51 
52 	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
53 	if (!keys_ex)
54 		return ERR_PTR(-ENOMEM);
55 
56 	k = keys_ex;
57 
58 	nla_for_each_nested(ka, nla, rem) {
59 		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
60 
61 		if (!n) {
62 			err = -EINVAL;
63 			goto err_out;
64 		}
65 		n--;
66 
67 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
68 			err = -EINVAL;
69 			goto err_out;
70 		}
71 
72 		err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
73 				       pedit_key_ex_policy, NULL);
74 		if (err)
75 			goto err_out;
76 
77 		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
78 		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
79 			err = -EINVAL;
80 			goto err_out;
81 		}
82 
83 		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
84 		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
85 
86 		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
87 		    k->cmd > TCA_PEDIT_CMD_MAX) {
88 			err = -EINVAL;
89 			goto err_out;
90 		}
91 
92 		k++;
93 	}
94 
95 	if (n) {
96 		err = -EINVAL;
97 		goto err_out;
98 	}
99 
100 	return keys_ex;
101 
102 err_out:
103 	kfree(keys_ex);
104 	return ERR_PTR(err);
105 }
106 
107 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
108 				 struct tcf_pedit_key_ex *keys_ex, int n)
109 {
110 	struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);
111 
112 	for (; n > 0; n--) {
113 		struct nlattr *key_start;
114 
115 		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
116 
117 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
118 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd)) {
119 			nlmsg_trim(skb, keys_start);
120 			return -EINVAL;
121 		}
122 
123 		nla_nest_end(skb, key_start);
124 
125 		keys_ex++;
126 	}
127 
128 	nla_nest_end(skb, keys_start);
129 
130 	return 0;
131 }
132 
133 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
134 			  struct nlattr *est, struct tc_action **a,
135 			  int ovr, int bind, struct netlink_ext_ack *extack)
136 {
137 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
138 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
139 	struct tc_pedit_key *keys = NULL;
140 	struct tcf_pedit_key_ex *keys_ex;
141 	struct tc_pedit *parm;
142 	struct nlattr *pattr;
143 	struct tcf_pedit *p;
144 	int ret = 0, err;
145 	int ksize;
146 
147 	if (!nla) {
148 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
149 		return -EINVAL;
150 	}
151 
152 	err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
153 	if (err < 0)
154 		return err;
155 
156 	pattr = tb[TCA_PEDIT_PARMS];
157 	if (!pattr)
158 		pattr = tb[TCA_PEDIT_PARMS_EX];
159 	if (!pattr) {
160 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
161 		return -EINVAL;
162 	}
163 
164 	parm = nla_data(pattr);
165 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
166 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
167 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
168 		return -EINVAL;
169 	}
170 
171 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
172 	if (IS_ERR(keys_ex))
173 		return PTR_ERR(keys_ex);
174 
175 	if (!tcf_idr_check(tn, parm->index, a, bind)) {
176 		if (!parm->nkeys) {
177 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
178 			ret = -EINVAL;
179 			goto out_free;
180 		}
181 		ret = tcf_idr_create(tn, parm->index, est, a,
182 				     &act_pedit_ops, bind, false);
183 		if (ret)
184 			goto out_free;
185 		p = to_pedit(*a);
186 		keys = kmalloc(ksize, GFP_KERNEL);
187 		if (!keys) {
188 			tcf_idr_release(*a, bind);
189 			ret = -ENOMEM;
190 			goto out_free;
191 		}
192 		ret = ACT_P_CREATED;
193 	} else {
194 		if (bind)
195 			goto out_free;
196 		tcf_idr_release(*a, bind);
197 		if (!ovr) {
198 			ret = -EEXIST;
199 			goto out_free;
200 		}
201 		p = to_pedit(*a);
202 		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
203 			keys = kmalloc(ksize, GFP_KERNEL);
204 			if (!keys) {
205 				ret = -ENOMEM;
206 				goto out_free;
207 			}
208 		}
209 	}
210 
211 	spin_lock_bh(&p->tcf_lock);
212 	p->tcfp_flags = parm->flags;
213 	p->tcf_action = parm->action;
214 	if (keys) {
215 		kfree(p->tcfp_keys);
216 		p->tcfp_keys = keys;
217 		p->tcfp_nkeys = parm->nkeys;
218 	}
219 	memcpy(p->tcfp_keys, parm->keys, ksize);
220 
221 	kfree(p->tcfp_keys_ex);
222 	p->tcfp_keys_ex = keys_ex;
223 
224 	spin_unlock_bh(&p->tcf_lock);
225 	if (ret == ACT_P_CREATED)
226 		tcf_idr_insert(tn, *a);
227 	return ret;
228 out_free:
229 	kfree(keys_ex);
230 	return ret;
231 
232 }
233 
234 static void tcf_pedit_cleanup(struct tc_action *a)
235 {
236 	struct tcf_pedit *p = to_pedit(a);
237 	struct tc_pedit_key *keys = p->tcfp_keys;
238 
239 	kfree(keys);
240 	kfree(p->tcfp_keys_ex);
241 }
242 
243 static bool offset_valid(struct sk_buff *skb, int offset)
244 {
245 	if (offset > 0 && offset > skb->len)
246 		return false;
247 
248 	if  (offset < 0 && -offset > skb_headroom(skb))
249 		return false;
250 
251 	return true;
252 }
253 
254 static int pedit_skb_hdr_offset(struct sk_buff *skb,
255 				enum pedit_header_type htype, int *hoffset)
256 {
257 	int ret = -EINVAL;
258 
259 	switch (htype) {
260 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
261 		if (skb_mac_header_was_set(skb)) {
262 			*hoffset = skb_mac_offset(skb);
263 			ret = 0;
264 		}
265 		break;
266 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
267 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
268 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
269 		*hoffset = skb_network_offset(skb);
270 		ret = 0;
271 		break;
272 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
273 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
274 		if (skb_transport_header_was_set(skb)) {
275 			*hoffset = skb_transport_offset(skb);
276 			ret = 0;
277 		}
278 		break;
279 	default:
280 		ret = -EINVAL;
281 		break;
282 	};
283 
284 	return ret;
285 }
286 
287 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
288 		     struct tcf_result *res)
289 {
290 	struct tcf_pedit *p = to_pedit(a);
291 	int i;
292 
293 	if (skb_unclone(skb, GFP_ATOMIC))
294 		return p->tcf_action;
295 
296 	spin_lock(&p->tcf_lock);
297 
298 	tcf_lastuse_update(&p->tcf_tm);
299 
300 	if (p->tcfp_nkeys > 0) {
301 		struct tc_pedit_key *tkey = p->tcfp_keys;
302 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
303 		enum pedit_header_type htype =
304 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
305 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
306 
307 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
308 			u32 *ptr, hdata;
309 			int offset = tkey->off;
310 			int hoffset;
311 			u32 val;
312 			int rc;
313 
314 			if (tkey_ex) {
315 				htype = tkey_ex->htype;
316 				cmd = tkey_ex->cmd;
317 
318 				tkey_ex++;
319 			}
320 
321 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
322 			if (rc) {
323 				pr_info("tc action pedit bad header type specified (0x%x)\n",
324 					htype);
325 				goto bad;
326 			}
327 
328 			if (tkey->offmask) {
329 				u8 *d, _d;
330 
331 				if (!offset_valid(skb, hoffset + tkey->at)) {
332 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
333 						hoffset + tkey->at);
334 					goto bad;
335 				}
336 				d = skb_header_pointer(skb, hoffset + tkey->at,
337 						       sizeof(_d), &_d);
338 				if (!d)
339 					goto bad;
340 				offset += (*d & tkey->offmask) >> tkey->shift;
341 			}
342 
343 			if (offset % 4) {
344 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
345 				goto bad;
346 			}
347 
348 			if (!offset_valid(skb, hoffset + offset)) {
349 				pr_info("tc action pedit offset %d out of bounds\n",
350 					hoffset + offset);
351 				goto bad;
352 			}
353 
354 			ptr = skb_header_pointer(skb, hoffset + offset,
355 						 sizeof(hdata), &hdata);
356 			if (!ptr)
357 				goto bad;
358 			/* just do it, baby */
359 			switch (cmd) {
360 			case TCA_PEDIT_KEY_EX_CMD_SET:
361 				val = tkey->val;
362 				break;
363 			case TCA_PEDIT_KEY_EX_CMD_ADD:
364 				val = (*ptr + tkey->val) & ~tkey->mask;
365 				break;
366 			default:
367 				pr_info("tc action pedit bad command (%d)\n",
368 					cmd);
369 				goto bad;
370 			}
371 
372 			*ptr = ((*ptr & tkey->mask) ^ val);
373 			if (ptr == &hdata)
374 				skb_store_bits(skb, hoffset + offset, ptr, 4);
375 		}
376 
377 		goto done;
378 	} else {
379 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
380 	}
381 
382 bad:
383 	p->tcf_qstats.overlimits++;
384 done:
385 	bstats_update(&p->tcf_bstats, skb);
386 	spin_unlock(&p->tcf_lock);
387 	return p->tcf_action;
388 }
389 
390 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
391 			  int bind, int ref)
392 {
393 	unsigned char *b = skb_tail_pointer(skb);
394 	struct tcf_pedit *p = to_pedit(a);
395 	struct tc_pedit *opt;
396 	struct tcf_t t;
397 	int s;
398 
399 	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
400 
401 	/* netlink spinlocks held above us - must use ATOMIC */
402 	opt = kzalloc(s, GFP_ATOMIC);
403 	if (unlikely(!opt))
404 		return -ENOBUFS;
405 
406 	memcpy(opt->keys, p->tcfp_keys,
407 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
408 	opt->index = p->tcf_index;
409 	opt->nkeys = p->tcfp_nkeys;
410 	opt->flags = p->tcfp_flags;
411 	opt->action = p->tcf_action;
412 	opt->refcnt = p->tcf_refcnt - ref;
413 	opt->bindcnt = p->tcf_bindcnt - bind;
414 
415 	if (p->tcfp_keys_ex) {
416 		tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
417 
418 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
419 			goto nla_put_failure;
420 	} else {
421 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
422 			goto nla_put_failure;
423 	}
424 
425 	tcf_tm_dump(&t, &p->tcf_tm);
426 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
427 		goto nla_put_failure;
428 
429 	kfree(opt);
430 	return skb->len;
431 
432 nla_put_failure:
433 	nlmsg_trim(skb, b);
434 	kfree(opt);
435 	return -1;
436 }
437 
438 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
439 			    struct netlink_callback *cb, int type,
440 			    const struct tc_action_ops *ops,
441 			    struct netlink_ext_ack *extack)
442 {
443 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
444 
445 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
446 }
447 
448 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index,
449 			    struct netlink_ext_ack *extack)
450 {
451 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
452 
453 	return tcf_idr_search(tn, a, index);
454 }
455 
456 static struct tc_action_ops act_pedit_ops = {
457 	.kind		=	"pedit",
458 	.type		=	TCA_ACT_PEDIT,
459 	.owner		=	THIS_MODULE,
460 	.act		=	tcf_pedit,
461 	.dump		=	tcf_pedit_dump,
462 	.cleanup	=	tcf_pedit_cleanup,
463 	.init		=	tcf_pedit_init,
464 	.walk		=	tcf_pedit_walker,
465 	.lookup		=	tcf_pedit_search,
466 	.size		=	sizeof(struct tcf_pedit),
467 };
468 
469 static __net_init int pedit_init_net(struct net *net)
470 {
471 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
472 
473 	return tc_action_net_init(tn, &act_pedit_ops);
474 }
475 
476 static void __net_exit pedit_exit_net(struct list_head *net_list)
477 {
478 	tc_action_net_exit(net_list, pedit_net_id);
479 }
480 
481 static struct pernet_operations pedit_net_ops = {
482 	.init = pedit_init_net,
483 	.exit_batch = pedit_exit_net,
484 	.id   = &pedit_net_id,
485 	.size = sizeof(struct tc_action_net),
486 };
487 
488 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
489 MODULE_DESCRIPTION("Generic Packet Editor actions");
490 MODULE_LICENSE("GPL");
491 
492 static int __init pedit_init_module(void)
493 {
494 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
495 }
496 
497 static void __exit pedit_cleanup_module(void)
498 {
499 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
500 }
501 
502 module_init(pedit_init_module);
503 module_exit(pedit_cleanup_module);
504 
505