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,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, struct netlink_ext_ack *extack)
141 {
142 struct tc_action_net *tn = net_generic(net, pedit_net_id);
143 struct nlattr *tb[TCA_PEDIT_MAX + 1];
144 struct tcf_chain *goto_ch = NULL;
145 struct tc_pedit_key *keys = NULL;
146 struct tcf_pedit_key_ex *keys_ex;
147 struct tc_pedit *parm;
148 struct nlattr *pattr;
149 struct tcf_pedit *p;
150 int ret = 0, err;
151 int ksize;
152 u32 index;
153
154 if (!nla) {
155 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
156 return -EINVAL;
157 }
158
159 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
160 pedit_policy, NULL);
161 if (err < 0)
162 return err;
163
164 pattr = tb[TCA_PEDIT_PARMS];
165 if (!pattr)
166 pattr = tb[TCA_PEDIT_PARMS_EX];
167 if (!pattr) {
168 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
169 return -EINVAL;
170 }
171
172 parm = nla_data(pattr);
173 if (!parm->nkeys) {
174 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
175 return -EINVAL;
176 }
177 ksize = parm->nkeys * sizeof(struct tc_pedit_key);
178 if (nla_len(pattr) < sizeof(*parm) + ksize) {
179 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
180 return -EINVAL;
181 }
182
183 keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
184 if (IS_ERR(keys_ex))
185 return PTR_ERR(keys_ex);
186
187 index = parm->index;
188 err = tcf_idr_check_alloc(tn, &index, a, bind);
189 if (!err) {
190 ret = tcf_idr_create(tn, index, est, a,
191 &act_pedit_ops, bind, false);
192 if (ret) {
193 tcf_idr_cleanup(tn, index);
194 goto out_free;
195 }
196 ret = ACT_P_CREATED;
197 } else if (err > 0) {
198 if (bind)
199 goto out_free;
200 if (!ovr) {
201 ret = -EEXIST;
202 goto out_release;
203 }
204 } else {
205 ret = err;
206 goto out_free;
207 }
208
209 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
210 if (err < 0) {
211 ret = err;
212 goto out_release;
213 }
214 p = to_pedit(*a);
215 spin_lock_bh(&p->tcf_lock);
216
217 if (ret == ACT_P_CREATED ||
218 (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
219 keys = kmalloc(ksize, GFP_ATOMIC);
220 if (!keys) {
221 spin_unlock_bh(&p->tcf_lock);
222 ret = -ENOMEM;
223 goto put_chain;
224 }
225 kfree(p->tcfp_keys);
226 p->tcfp_keys = keys;
227 p->tcfp_nkeys = parm->nkeys;
228 }
229 memcpy(p->tcfp_keys, parm->keys, ksize);
230
231 p->tcfp_flags = parm->flags;
232 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
233
234 kfree(p->tcfp_keys_ex);
235 p->tcfp_keys_ex = keys_ex;
236
237 spin_unlock_bh(&p->tcf_lock);
238 if (goto_ch)
239 tcf_chain_put_by_act(goto_ch);
240 if (ret == ACT_P_CREATED)
241 tcf_idr_insert(tn, *a);
242 return ret;
243
244 put_chain:
245 if (goto_ch)
246 tcf_chain_put_by_act(goto_ch);
247 out_release:
248 tcf_idr_release(*a, bind);
249 out_free:
250 kfree(keys_ex);
251 return ret;
252
253 }
254
tcf_pedit_cleanup(struct tc_action * a)255 static void tcf_pedit_cleanup(struct tc_action *a)
256 {
257 struct tcf_pedit *p = to_pedit(a);
258 struct tc_pedit_key *keys = p->tcfp_keys;
259
260 kfree(keys);
261 kfree(p->tcfp_keys_ex);
262 }
263
offset_valid(struct sk_buff * skb,int offset)264 static bool offset_valid(struct sk_buff *skb, int offset)
265 {
266 if (offset > 0 && offset > skb->len)
267 return false;
268
269 if (offset < 0 && -offset > skb_headroom(skb))
270 return false;
271
272 return true;
273 }
274
pedit_skb_hdr_offset(struct sk_buff * skb,enum pedit_header_type htype,int * hoffset)275 static int pedit_skb_hdr_offset(struct sk_buff *skb,
276 enum pedit_header_type htype, int *hoffset)
277 {
278 int ret = -EINVAL;
279
280 switch (htype) {
281 case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
282 if (skb_mac_header_was_set(skb)) {
283 *hoffset = skb_mac_offset(skb);
284 ret = 0;
285 }
286 break;
287 case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
288 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
289 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
290 *hoffset = skb_network_offset(skb);
291 ret = 0;
292 break;
293 case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
294 case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
295 if (skb_transport_header_was_set(skb)) {
296 *hoffset = skb_transport_offset(skb);
297 ret = 0;
298 }
299 break;
300 default:
301 ret = -EINVAL;
302 break;
303 }
304
305 return ret;
306 }
307
tcf_pedit_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)308 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
309 struct tcf_result *res)
310 {
311 struct tcf_pedit *p = to_pedit(a);
312 int i;
313
314 if (skb_unclone(skb, GFP_ATOMIC))
315 return p->tcf_action;
316
317 spin_lock(&p->tcf_lock);
318
319 tcf_lastuse_update(&p->tcf_tm);
320
321 if (p->tcfp_nkeys > 0) {
322 struct tc_pedit_key *tkey = p->tcfp_keys;
323 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
324 enum pedit_header_type htype =
325 TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
326 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
327
328 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
329 u32 *ptr, hdata;
330 int offset = tkey->off;
331 int hoffset;
332 u32 val;
333 int rc;
334
335 if (tkey_ex) {
336 htype = tkey_ex->htype;
337 cmd = tkey_ex->cmd;
338
339 tkey_ex++;
340 }
341
342 rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
343 if (rc) {
344 pr_info("tc action pedit bad header type specified (0x%x)\n",
345 htype);
346 goto bad;
347 }
348
349 if (tkey->offmask) {
350 u8 *d, _d;
351
352 if (!offset_valid(skb, hoffset + tkey->at)) {
353 pr_info("tc action pedit 'at' offset %d out of bounds\n",
354 hoffset + tkey->at);
355 goto bad;
356 }
357 d = skb_header_pointer(skb, hoffset + tkey->at,
358 sizeof(_d), &_d);
359 if (!d)
360 goto bad;
361 offset += (*d & tkey->offmask) >> tkey->shift;
362 }
363
364 if (offset % 4) {
365 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
366 goto bad;
367 }
368
369 if (!offset_valid(skb, hoffset + offset)) {
370 pr_info("tc action pedit offset %d out of bounds\n",
371 hoffset + offset);
372 goto bad;
373 }
374
375 ptr = skb_header_pointer(skb, hoffset + offset,
376 sizeof(hdata), &hdata);
377 if (!ptr)
378 goto bad;
379 /* just do it, baby */
380 switch (cmd) {
381 case TCA_PEDIT_KEY_EX_CMD_SET:
382 val = tkey->val;
383 break;
384 case TCA_PEDIT_KEY_EX_CMD_ADD:
385 val = (*ptr + tkey->val) & ~tkey->mask;
386 break;
387 default:
388 pr_info("tc action pedit bad command (%d)\n",
389 cmd);
390 goto bad;
391 }
392
393 *ptr = ((*ptr & tkey->mask) ^ val);
394 if (ptr == &hdata)
395 skb_store_bits(skb, hoffset + offset, ptr, 4);
396 }
397
398 goto done;
399 } else {
400 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
401 }
402
403 bad:
404 p->tcf_qstats.overlimits++;
405 done:
406 bstats_update(&p->tcf_bstats, skb);
407 spin_unlock(&p->tcf_lock);
408 return p->tcf_action;
409 }
410
tcf_pedit_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)411 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
412 int bind, int ref)
413 {
414 unsigned char *b = skb_tail_pointer(skb);
415 struct tcf_pedit *p = to_pedit(a);
416 struct tc_pedit *opt;
417 struct tcf_t t;
418 int s;
419
420 s = struct_size(opt, keys, p->tcfp_nkeys);
421
422 /* netlink spinlocks held above us - must use ATOMIC */
423 opt = kzalloc(s, GFP_ATOMIC);
424 if (unlikely(!opt))
425 return -ENOBUFS;
426
427 spin_lock_bh(&p->tcf_lock);
428 memcpy(opt->keys, p->tcfp_keys,
429 p->tcfp_nkeys * sizeof(struct tc_pedit_key));
430 opt->index = p->tcf_index;
431 opt->nkeys = p->tcfp_nkeys;
432 opt->flags = p->tcfp_flags;
433 opt->action = p->tcf_action;
434 opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
435 opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
436
437 if (p->tcfp_keys_ex) {
438 if (tcf_pedit_key_ex_dump(skb,
439 p->tcfp_keys_ex,
440 p->tcfp_nkeys))
441 goto nla_put_failure;
442
443 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
444 goto nla_put_failure;
445 } else {
446 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
447 goto nla_put_failure;
448 }
449
450 tcf_tm_dump(&t, &p->tcf_tm);
451 if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
452 goto nla_put_failure;
453 spin_unlock_bh(&p->tcf_lock);
454
455 kfree(opt);
456 return skb->len;
457
458 nla_put_failure:
459 spin_unlock_bh(&p->tcf_lock);
460 nlmsg_trim(skb, b);
461 kfree(opt);
462 return -1;
463 }
464
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)465 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
466 struct netlink_callback *cb, int type,
467 const struct tc_action_ops *ops,
468 struct netlink_ext_ack *extack)
469 {
470 struct tc_action_net *tn = net_generic(net, pedit_net_id);
471
472 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
473 }
474
tcf_pedit_search(struct net * net,struct tc_action ** a,u32 index)475 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
476 {
477 struct tc_action_net *tn = net_generic(net, pedit_net_id);
478
479 return tcf_idr_search(tn, a, index);
480 }
481
482 static struct tc_action_ops act_pedit_ops = {
483 .kind = "pedit",
484 .id = TCA_ID_PEDIT,
485 .owner = THIS_MODULE,
486 .act = tcf_pedit_act,
487 .dump = tcf_pedit_dump,
488 .cleanup = tcf_pedit_cleanup,
489 .init = tcf_pedit_init,
490 .walk = tcf_pedit_walker,
491 .lookup = tcf_pedit_search,
492 .size = sizeof(struct tcf_pedit),
493 };
494
pedit_init_net(struct net * net)495 static __net_init int pedit_init_net(struct net *net)
496 {
497 struct tc_action_net *tn = net_generic(net, pedit_net_id);
498
499 return tc_action_net_init(net, tn, &act_pedit_ops);
500 }
501
pedit_exit_net(struct list_head * net_list)502 static void __net_exit pedit_exit_net(struct list_head *net_list)
503 {
504 tc_action_net_exit(net_list, pedit_net_id);
505 }
506
507 static struct pernet_operations pedit_net_ops = {
508 .init = pedit_init_net,
509 .exit_batch = pedit_exit_net,
510 .id = &pedit_net_id,
511 .size = sizeof(struct tc_action_net),
512 };
513
514 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
515 MODULE_DESCRIPTION("Generic Packet Editor actions");
516 MODULE_LICENSE("GPL");
517
pedit_init_module(void)518 static int __init pedit_init_module(void)
519 {
520 return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
521 }
522
pedit_cleanup_module(void)523 static void __exit pedit_cleanup_module(void)
524 {
525 tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
526 }
527
528 module_init(pedit_init_module);
529 module_exit(pedit_cleanup_module);
530