xref: /kernel/linux/linux-5.10/net/sched/act_pedit.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/act_pedit.c	Generic packet editor
4 *
5 * Authors:	Jamal Hadi Salim (2002-4)
6 */
7
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <linux/string.h>
11#include <linux/errno.h>
12#include <linux/skbuff.h>
13#include <linux/rtnetlink.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <net/netlink.h>
18#include <net/pkt_sched.h>
19#include <linux/tc_act/tc_pedit.h>
20#include <net/tc_act/tc_pedit.h>
21#include <uapi/linux/tc_act/tc_pedit.h>
22#include <net/pkt_cls.h>
23
24static unsigned int pedit_net_id;
25static struct tc_action_ops act_pedit_ops;
26
27static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
28	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
29	[TCA_PEDIT_PARMS_EX]	= { .len = sizeof(struct tc_pedit) },
30	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
31};
32
33static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
34	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
35	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
36};
37
38static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
39							u8 n)
40{
41	struct tcf_pedit_key_ex *keys_ex;
42	struct tcf_pedit_key_ex *k;
43	const struct nlattr *ka;
44	int err = -EINVAL;
45	int rem;
46
47	if (!nla)
48		return NULL;
49
50	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
51	if (!keys_ex)
52		return ERR_PTR(-ENOMEM);
53
54	k = keys_ex;
55
56	nla_for_each_nested(ka, nla, rem) {
57		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
58
59		if (!n) {
60			err = -EINVAL;
61			goto err_out;
62		}
63		n--;
64
65		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
66			err = -EINVAL;
67			goto err_out;
68		}
69
70		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
71						  ka, pedit_key_ex_policy,
72						  NULL);
73		if (err)
74			goto err_out;
75
76		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
77		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
78			err = -EINVAL;
79			goto err_out;
80		}
81
82		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
83		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
84
85		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
86		    k->cmd > TCA_PEDIT_CMD_MAX) {
87			err = -EINVAL;
88			goto err_out;
89		}
90
91		k++;
92	}
93
94	if (n) {
95		err = -EINVAL;
96		goto err_out;
97	}
98
99	return keys_ex;
100
101err_out:
102	kfree(keys_ex);
103	return ERR_PTR(err);
104}
105
106static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
107				 struct tcf_pedit_key_ex *keys_ex, int n)
108{
109	struct nlattr *keys_start = nla_nest_start_noflag(skb,
110							  TCA_PEDIT_KEYS_EX);
111
112	if (!keys_start)
113		goto nla_failure;
114	for (; n > 0; n--) {
115		struct nlattr *key_start;
116
117		key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
118		if (!key_start)
119			goto nla_failure;
120
121		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
122		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
123			goto nla_failure;
124
125		nla_nest_end(skb, key_start);
126
127		keys_ex++;
128	}
129
130	nla_nest_end(skb, keys_start);
131
132	return 0;
133nla_failure:
134	nla_nest_cancel(skb, keys_start);
135	return -EINVAL;
136}
137
138static int tcf_pedit_init(struct net *net, struct nlattr *nla,
139			  struct nlattr *est, struct tc_action **a,
140			  int ovr, int bind, bool rtnl_held,
141			  struct tcf_proto *tp, u32 flags,
142			  struct netlink_ext_ack *extack)
143{
144	struct tc_action_net *tn = net_generic(net, pedit_net_id);
145	struct nlattr *tb[TCA_PEDIT_MAX + 1];
146	struct tcf_chain *goto_ch = NULL;
147	struct tc_pedit_key *keys = NULL;
148	struct tcf_pedit_key_ex *keys_ex;
149	struct tc_pedit *parm;
150	struct nlattr *pattr;
151	struct tcf_pedit *p;
152	int ret = 0, err;
153	int i, ksize;
154	u32 index;
155
156	if (!nla) {
157		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
158		return -EINVAL;
159	}
160
161	err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
162					  pedit_policy, NULL);
163	if (err < 0)
164		return err;
165
166	pattr = tb[TCA_PEDIT_PARMS];
167	if (!pattr)
168		pattr = tb[TCA_PEDIT_PARMS_EX];
169	if (!pattr) {
170		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
171		return -EINVAL;
172	}
173
174	parm = nla_data(pattr);
175	if (!parm->nkeys) {
176		NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
177		return -EINVAL;
178	}
179	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
180	if (nla_len(pattr) < sizeof(*parm) + ksize) {
181		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
182		return -EINVAL;
183	}
184
185	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
186	if (IS_ERR(keys_ex))
187		return PTR_ERR(keys_ex);
188
189	index = parm->index;
190	err = tcf_idr_check_alloc(tn, &index, a, bind);
191	if (!err) {
192		ret = tcf_idr_create(tn, index, est, a,
193				     &act_pedit_ops, bind, false, flags);
194		if (ret) {
195			tcf_idr_cleanup(tn, index);
196			goto out_free;
197		}
198		ret = ACT_P_CREATED;
199	} else if (err > 0) {
200		if (bind)
201			goto out_free;
202		if (!ovr) {
203			ret = -EEXIST;
204			goto out_release;
205		}
206	} else {
207		ret = err;
208		goto out_free;
209	}
210
211	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
212	if (err < 0) {
213		ret = err;
214		goto out_release;
215	}
216	p = to_pedit(*a);
217	spin_lock_bh(&p->tcf_lock);
218
219	if (ret == ACT_P_CREATED ||
220	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
221		keys = kmalloc(ksize, GFP_ATOMIC);
222		if (!keys) {
223			spin_unlock_bh(&p->tcf_lock);
224			ret = -ENOMEM;
225			goto put_chain;
226		}
227		kfree(p->tcfp_keys);
228		p->tcfp_keys = keys;
229		p->tcfp_nkeys = parm->nkeys;
230	}
231	memcpy(p->tcfp_keys, parm->keys, ksize);
232	p->tcfp_off_max_hint = 0;
233	for (i = 0; i < p->tcfp_nkeys; ++i) {
234		u32 cur = p->tcfp_keys[i].off;
235
236		/* sanitize the shift value for any later use */
237		p->tcfp_keys[i].shift = min_t(size_t, BITS_PER_TYPE(int) - 1,
238					      p->tcfp_keys[i].shift);
239
240		/* The AT option can read a single byte, we can bound the actual
241		 * value with uchar max.
242		 */
243		cur += (0xff & p->tcfp_keys[i].offmask) >> p->tcfp_keys[i].shift;
244
245		/* Each key touches 4 bytes starting from the computed offset */
246		p->tcfp_off_max_hint = max(p->tcfp_off_max_hint, cur + 4);
247	}
248
249	p->tcfp_flags = parm->flags;
250	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
251
252	kfree(p->tcfp_keys_ex);
253	p->tcfp_keys_ex = keys_ex;
254
255	spin_unlock_bh(&p->tcf_lock);
256	if (goto_ch)
257		tcf_chain_put_by_act(goto_ch);
258	return ret;
259
260put_chain:
261	if (goto_ch)
262		tcf_chain_put_by_act(goto_ch);
263out_release:
264	tcf_idr_release(*a, bind);
265out_free:
266	kfree(keys_ex);
267	return ret;
268
269}
270
271static void tcf_pedit_cleanup(struct tc_action *a)
272{
273	struct tcf_pedit *p = to_pedit(a);
274	struct tc_pedit_key *keys = p->tcfp_keys;
275
276	kfree(keys);
277	kfree(p->tcfp_keys_ex);
278}
279
280static bool offset_valid(struct sk_buff *skb, int offset)
281{
282	if (offset > 0 && offset > skb->len)
283		return false;
284
285	if  (offset < 0 && -offset > skb_headroom(skb))
286		return false;
287
288	return true;
289}
290
291static int pedit_skb_hdr_offset(struct sk_buff *skb,
292				enum pedit_header_type htype, int *hoffset)
293{
294	int ret = -EINVAL;
295
296	switch (htype) {
297	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
298		if (skb_mac_header_was_set(skb)) {
299			*hoffset = skb_mac_offset(skb);
300			ret = 0;
301		}
302		break;
303	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
304	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
305	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
306		*hoffset = skb_network_offset(skb);
307		ret = 0;
308		break;
309	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
310	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
311		if (skb_transport_header_was_set(skb)) {
312			*hoffset = skb_transport_offset(skb);
313			ret = 0;
314		}
315		break;
316	default:
317		ret = -EINVAL;
318		break;
319	}
320
321	return ret;
322}
323
324static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
325			 struct tcf_result *res)
326{
327	struct tcf_pedit *p = to_pedit(a);
328	u32 max_offset;
329	int i;
330
331	spin_lock(&p->tcf_lock);
332
333	max_offset = (skb_transport_header_was_set(skb) ?
334		      skb_transport_offset(skb) :
335		      skb_network_offset(skb)) +
336		     p->tcfp_off_max_hint;
337	if (skb_ensure_writable(skb, min(skb->len, max_offset)))
338		goto unlock;
339
340	tcf_lastuse_update(&p->tcf_tm);
341
342	if (p->tcfp_nkeys > 0) {
343		struct tc_pedit_key *tkey = p->tcfp_keys;
344		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
345		enum pedit_header_type htype =
346			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
347		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
348
349		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
350			u32 *ptr, hdata;
351			int offset = tkey->off;
352			int hoffset;
353			u32 val;
354			int rc;
355
356			if (tkey_ex) {
357				htype = tkey_ex->htype;
358				cmd = tkey_ex->cmd;
359
360				tkey_ex++;
361			}
362
363			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
364			if (rc) {
365				pr_info("tc action pedit bad header type specified (0x%x)\n",
366					htype);
367				goto bad;
368			}
369
370			if (tkey->offmask) {
371				u8 *d, _d;
372
373				if (!offset_valid(skb, hoffset + tkey->at)) {
374					pr_info("tc action pedit 'at' offset %d out of bounds\n",
375						hoffset + tkey->at);
376					goto bad;
377				}
378				d = skb_header_pointer(skb, hoffset + tkey->at,
379						       sizeof(_d), &_d);
380				if (!d)
381					goto bad;
382				offset += (*d & tkey->offmask) >> tkey->shift;
383			}
384
385			if (offset % 4) {
386				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
387				goto bad;
388			}
389
390			if (!offset_valid(skb, hoffset + offset)) {
391				pr_info("tc action pedit offset %d out of bounds\n",
392					hoffset + offset);
393				goto bad;
394			}
395
396			ptr = skb_header_pointer(skb, hoffset + offset,
397						 sizeof(hdata), &hdata);
398			if (!ptr)
399				goto bad;
400			/* just do it, baby */
401			switch (cmd) {
402			case TCA_PEDIT_KEY_EX_CMD_SET:
403				val = tkey->val;
404				break;
405			case TCA_PEDIT_KEY_EX_CMD_ADD:
406				val = (*ptr + tkey->val) & ~tkey->mask;
407				break;
408			default:
409				pr_info("tc action pedit bad command (%d)\n",
410					cmd);
411				goto bad;
412			}
413
414			*ptr = ((*ptr & tkey->mask) ^ val);
415			if (ptr == &hdata)
416				skb_store_bits(skb, hoffset + offset, ptr, 4);
417		}
418
419		goto done;
420	} else {
421		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
422	}
423
424bad:
425	p->tcf_qstats.overlimits++;
426done:
427	bstats_update(&p->tcf_bstats, skb);
428unlock:
429	spin_unlock(&p->tcf_lock);
430	return p->tcf_action;
431}
432
433static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
434				   u64 drops, u64 lastuse, bool hw)
435{
436	struct tcf_pedit *d = to_pedit(a);
437	struct tcf_t *tm = &d->tcf_tm;
438
439	tcf_action_update_stats(a, bytes, packets, drops, hw);
440	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
441}
442
443static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
444			  int bind, int ref)
445{
446	unsigned char *b = skb_tail_pointer(skb);
447	struct tcf_pedit *p = to_pedit(a);
448	struct tc_pedit *opt;
449	struct tcf_t t;
450	int s;
451
452	s = struct_size(opt, keys, p->tcfp_nkeys);
453
454	/* netlink spinlocks held above us - must use ATOMIC */
455	opt = kzalloc(s, GFP_ATOMIC);
456	if (unlikely(!opt))
457		return -ENOBUFS;
458
459	spin_lock_bh(&p->tcf_lock);
460	memcpy(opt->keys, p->tcfp_keys, flex_array_size(opt, keys, p->tcfp_nkeys));
461	opt->index = p->tcf_index;
462	opt->nkeys = p->tcfp_nkeys;
463	opt->flags = p->tcfp_flags;
464	opt->action = p->tcf_action;
465	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
466	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
467
468	if (p->tcfp_keys_ex) {
469		if (tcf_pedit_key_ex_dump(skb,
470					  p->tcfp_keys_ex,
471					  p->tcfp_nkeys))
472			goto nla_put_failure;
473
474		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
475			goto nla_put_failure;
476	} else {
477		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
478			goto nla_put_failure;
479	}
480
481	tcf_tm_dump(&t, &p->tcf_tm);
482	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
483		goto nla_put_failure;
484	spin_unlock_bh(&p->tcf_lock);
485
486	kfree(opt);
487	return skb->len;
488
489nla_put_failure:
490	spin_unlock_bh(&p->tcf_lock);
491	nlmsg_trim(skb, b);
492	kfree(opt);
493	return -1;
494}
495
496static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
497			    struct netlink_callback *cb, int type,
498			    const struct tc_action_ops *ops,
499			    struct netlink_ext_ack *extack)
500{
501	struct tc_action_net *tn = net_generic(net, pedit_net_id);
502
503	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
504}
505
506static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
507{
508	struct tc_action_net *tn = net_generic(net, pedit_net_id);
509
510	return tcf_idr_search(tn, a, index);
511}
512
513static struct tc_action_ops act_pedit_ops = {
514	.kind		=	"pedit",
515	.id		=	TCA_ID_PEDIT,
516	.owner		=	THIS_MODULE,
517	.act		=	tcf_pedit_act,
518	.stats_update	=	tcf_pedit_stats_update,
519	.dump		=	tcf_pedit_dump,
520	.cleanup	=	tcf_pedit_cleanup,
521	.init		=	tcf_pedit_init,
522	.walk		=	tcf_pedit_walker,
523	.lookup		=	tcf_pedit_search,
524	.size		=	sizeof(struct tcf_pedit),
525};
526
527static __net_init int pedit_init_net(struct net *net)
528{
529	struct tc_action_net *tn = net_generic(net, pedit_net_id);
530
531	return tc_action_net_init(net, tn, &act_pedit_ops);
532}
533
534static void __net_exit pedit_exit_net(struct list_head *net_list)
535{
536	tc_action_net_exit(net_list, pedit_net_id);
537}
538
539static struct pernet_operations pedit_net_ops = {
540	.init = pedit_init_net,
541	.exit_batch = pedit_exit_net,
542	.id   = &pedit_net_id,
543	.size = sizeof(struct tc_action_net),
544};
545
546MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
547MODULE_DESCRIPTION("Generic Packet Editor actions");
548MODULE_LICENSE("GPL");
549
550static int __init pedit_init_module(void)
551{
552	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
553}
554
555static void __exit pedit_cleanup_module(void)
556{
557	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
558}
559
560module_init(pedit_init_module);
561module_exit(pedit_cleanup_module);
562