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