xref: /openbmc/linux/net/sched/act_mpls.c (revision b3be9488)
1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Netronome Systems, Inc. */
3 
4 #include <linux/if_arp.h>
5 #include <linux/init.h>
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/mpls.h>
9 #include <linux/rtnetlink.h>
10 #include <linux/skbuff.h>
11 #include <linux/tc_act/tc_mpls.h>
12 #include <net/mpls.h>
13 #include <net/netlink.h>
14 #include <net/pkt_sched.h>
15 #include <net/pkt_cls.h>
16 #include <net/tc_act/tc_mpls.h>
17 #include <net/tc_wrapper.h>
18 
19 static struct tc_action_ops act_mpls_ops;
20 
21 #define ACT_MPLS_TTL_DEFAULT	255
22 
tcf_mpls_get_lse(struct mpls_shim_hdr * lse,struct tcf_mpls_params * p,bool set_bos)23 static __be32 tcf_mpls_get_lse(struct mpls_shim_hdr *lse,
24 			       struct tcf_mpls_params *p, bool set_bos)
25 {
26 	u32 new_lse = 0;
27 
28 	if (lse)
29 		new_lse = be32_to_cpu(lse->label_stack_entry);
30 
31 	if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET) {
32 		new_lse &= ~MPLS_LS_LABEL_MASK;
33 		new_lse |= p->tcfm_label << MPLS_LS_LABEL_SHIFT;
34 	}
35 	if (p->tcfm_ttl) {
36 		new_lse &= ~MPLS_LS_TTL_MASK;
37 		new_lse |= p->tcfm_ttl << MPLS_LS_TTL_SHIFT;
38 	}
39 	if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET) {
40 		new_lse &= ~MPLS_LS_TC_MASK;
41 		new_lse |= p->tcfm_tc << MPLS_LS_TC_SHIFT;
42 	}
43 	if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET) {
44 		new_lse &= ~MPLS_LS_S_MASK;
45 		new_lse |= p->tcfm_bos << MPLS_LS_S_SHIFT;
46 	} else if (set_bos) {
47 		new_lse |= 1 << MPLS_LS_S_SHIFT;
48 	}
49 
50 	return cpu_to_be32(new_lse);
51 }
52 
tcf_mpls_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)53 TC_INDIRECT_SCOPE int tcf_mpls_act(struct sk_buff *skb,
54 				   const struct tc_action *a,
55 				   struct tcf_result *res)
56 {
57 	struct tcf_mpls *m = to_mpls(a);
58 	struct tcf_mpls_params *p;
59 	__be32 new_lse;
60 	int ret, mac_len;
61 
62 	tcf_lastuse_update(&m->tcf_tm);
63 	bstats_update(this_cpu_ptr(m->common.cpu_bstats), skb);
64 
65 	/* Ensure 'data' points at mac_header prior calling mpls manipulating
66 	 * functions.
67 	 */
68 	if (skb_at_tc_ingress(skb)) {
69 		skb_push_rcsum(skb, skb->mac_len);
70 		mac_len = skb->mac_len;
71 	} else {
72 		mac_len = skb_network_offset(skb);
73 	}
74 
75 	ret = READ_ONCE(m->tcf_action);
76 
77 	p = rcu_dereference_bh(m->mpls_p);
78 
79 	switch (p->tcfm_action) {
80 	case TCA_MPLS_ACT_POP:
81 		if (skb_mpls_pop(skb, p->tcfm_proto, mac_len,
82 				 skb->dev && skb->dev->type == ARPHRD_ETHER))
83 			goto drop;
84 		break;
85 	case TCA_MPLS_ACT_PUSH:
86 		new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb_protocol(skb, true)));
87 		if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len,
88 				  skb->dev && skb->dev->type == ARPHRD_ETHER))
89 			goto drop;
90 		break;
91 	case TCA_MPLS_ACT_MAC_PUSH:
92 		if (skb_vlan_tag_present(skb)) {
93 			if (__vlan_insert_inner_tag(skb, skb->vlan_proto,
94 						    skb_vlan_tag_get(skb),
95 						    ETH_HLEN) < 0)
96 				goto drop;
97 
98 			skb->protocol = skb->vlan_proto;
99 			__vlan_hwaccel_clear_tag(skb);
100 		}
101 
102 		new_lse = tcf_mpls_get_lse(NULL, p, mac_len ||
103 					   !eth_p_mpls(skb->protocol));
104 
105 		if (skb_mpls_push(skb, new_lse, p->tcfm_proto, 0, false))
106 			goto drop;
107 		break;
108 	case TCA_MPLS_ACT_MODIFY:
109 		if (!pskb_may_pull(skb,
110 				   skb_network_offset(skb) + MPLS_HLEN))
111 			goto drop;
112 		new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
113 		if (skb_mpls_update_lse(skb, new_lse))
114 			goto drop;
115 		break;
116 	case TCA_MPLS_ACT_DEC_TTL:
117 		if (skb_mpls_dec_ttl(skb))
118 			goto drop;
119 		break;
120 	}
121 
122 	if (skb_at_tc_ingress(skb))
123 		skb_pull_rcsum(skb, skb->mac_len);
124 
125 	return ret;
126 
127 drop:
128 	qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
129 	return TC_ACT_SHOT;
130 }
131 
valid_label(const struct nlattr * attr,struct netlink_ext_ack * extack)132 static int valid_label(const struct nlattr *attr,
133 		       struct netlink_ext_ack *extack)
134 {
135 	const u32 *label = nla_data(attr);
136 
137 	if (nla_len(attr) != sizeof(*label)) {
138 		NL_SET_ERR_MSG_MOD(extack, "Invalid MPLS label length");
139 		return -EINVAL;
140 	}
141 
142 	if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
143 		NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
144 		return -EINVAL;
145 	}
146 
147 	return 0;
148 }
149 
150 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
151 	[TCA_MPLS_PARMS]	= NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
152 	[TCA_MPLS_PROTO]	= { .type = NLA_U16 },
153 	[TCA_MPLS_LABEL]	= NLA_POLICY_VALIDATE_FN(NLA_BINARY,
154 							 valid_label),
155 	[TCA_MPLS_TC]		= NLA_POLICY_RANGE(NLA_U8, 0, 7),
156 	[TCA_MPLS_TTL]		= NLA_POLICY_MIN(NLA_U8, 1),
157 	[TCA_MPLS_BOS]		= NLA_POLICY_RANGE(NLA_U8, 0, 1),
158 };
159 
tcf_mpls_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,struct tcf_proto * tp,u32 flags,struct netlink_ext_ack * extack)160 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
161 			 struct nlattr *est, struct tc_action **a,
162 			 struct tcf_proto *tp, u32 flags,
163 			 struct netlink_ext_ack *extack)
164 {
165 	struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
166 	bool bind = flags & TCA_ACT_FLAGS_BIND;
167 	struct nlattr *tb[TCA_MPLS_MAX + 1];
168 	struct tcf_chain *goto_ch = NULL;
169 	struct tcf_mpls_params *p;
170 	struct tc_mpls *parm;
171 	bool exists = false;
172 	struct tcf_mpls *m;
173 	int ret = 0, err;
174 	u8 mpls_ttl = 0;
175 	u32 index;
176 
177 	if (!nla) {
178 		NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
179 		return -EINVAL;
180 	}
181 
182 	err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
183 	if (err < 0)
184 		return err;
185 
186 	if (!tb[TCA_MPLS_PARMS]) {
187 		NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
188 		return -EINVAL;
189 	}
190 	parm = nla_data(tb[TCA_MPLS_PARMS]);
191 	index = parm->index;
192 
193 	err = tcf_idr_check_alloc(tn, &index, a, bind);
194 	if (err < 0)
195 		return err;
196 	exists = err;
197 	if (exists && bind)
198 		return 0;
199 
200 	if (!exists) {
201 		ret = tcf_idr_create(tn, index, est, a, &act_mpls_ops, bind,
202 				     true, flags);
203 		if (ret) {
204 			tcf_idr_cleanup(tn, index);
205 			return ret;
206 		}
207 
208 		ret = ACT_P_CREATED;
209 	} else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
210 		tcf_idr_release(*a, bind);
211 		return -EEXIST;
212 	}
213 
214 	/* Verify parameters against action type. */
215 	switch (parm->m_action) {
216 	case TCA_MPLS_ACT_POP:
217 		if (!tb[TCA_MPLS_PROTO]) {
218 			NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
219 			err = -EINVAL;
220 			goto release_idr;
221 		}
222 		if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
223 			NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
224 			err = -EINVAL;
225 			goto release_idr;
226 		}
227 		if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
228 		    tb[TCA_MPLS_BOS]) {
229 			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
230 			err = -EINVAL;
231 			goto release_idr;
232 		}
233 		break;
234 	case TCA_MPLS_ACT_DEC_TTL:
235 		if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
236 		    tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
237 			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
238 			err = -EINVAL;
239 			goto release_idr;
240 		}
241 		break;
242 	case TCA_MPLS_ACT_PUSH:
243 	case TCA_MPLS_ACT_MAC_PUSH:
244 		if (!tb[TCA_MPLS_LABEL]) {
245 			NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
246 			err = -EINVAL;
247 			goto release_idr;
248 		}
249 		if (tb[TCA_MPLS_PROTO] &&
250 		    !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
251 			NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
252 			err = -EPROTONOSUPPORT;
253 			goto release_idr;
254 		}
255 		/* Push needs a TTL - if not specified, set a default value. */
256 		if (!tb[TCA_MPLS_TTL]) {
257 #if IS_ENABLED(CONFIG_MPLS)
258 			mpls_ttl = net->mpls.default_ttl ?
259 				   net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
260 #else
261 			mpls_ttl = ACT_MPLS_TTL_DEFAULT;
262 #endif
263 		}
264 		break;
265 	case TCA_MPLS_ACT_MODIFY:
266 		if (tb[TCA_MPLS_PROTO]) {
267 			NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
268 			err = -EINVAL;
269 			goto release_idr;
270 		}
271 		break;
272 	default:
273 		NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
274 		err = -EINVAL;
275 		goto release_idr;
276 	}
277 
278 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
279 	if (err < 0)
280 		goto release_idr;
281 
282 	m = to_mpls(*a);
283 
284 	p = kzalloc(sizeof(*p), GFP_KERNEL);
285 	if (!p) {
286 		err = -ENOMEM;
287 		goto put_chain;
288 	}
289 
290 	p->tcfm_action = parm->m_action;
291 	p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
292 					     ACT_MPLS_LABEL_NOT_SET;
293 	p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
294 				       ACT_MPLS_TC_NOT_SET;
295 	p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
296 					 mpls_ttl;
297 	p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
298 					 ACT_MPLS_BOS_NOT_SET;
299 	p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
300 					     htons(ETH_P_MPLS_UC);
301 
302 	spin_lock_bh(&m->tcf_lock);
303 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
304 	p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
305 	spin_unlock_bh(&m->tcf_lock);
306 
307 	if (goto_ch)
308 		tcf_chain_put_by_act(goto_ch);
309 	if (p)
310 		kfree_rcu(p, rcu);
311 
312 	return ret;
313 put_chain:
314 	if (goto_ch)
315 		tcf_chain_put_by_act(goto_ch);
316 release_idr:
317 	tcf_idr_release(*a, bind);
318 	return err;
319 }
320 
tcf_mpls_cleanup(struct tc_action * a)321 static void tcf_mpls_cleanup(struct tc_action *a)
322 {
323 	struct tcf_mpls *m = to_mpls(a);
324 	struct tcf_mpls_params *p;
325 
326 	p = rcu_dereference_protected(m->mpls_p, 1);
327 	if (p)
328 		kfree_rcu(p, rcu);
329 }
330 
tcf_mpls_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)331 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
332 			 int bind, int ref)
333 {
334 	unsigned char *b = skb_tail_pointer(skb);
335 	struct tcf_mpls *m = to_mpls(a);
336 	struct tcf_mpls_params *p;
337 	struct tc_mpls opt = {
338 		.index    = m->tcf_index,
339 		.refcnt   = refcount_read(&m->tcf_refcnt) - ref,
340 		.bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
341 	};
342 	struct tcf_t t;
343 
344 	spin_lock_bh(&m->tcf_lock);
345 	opt.action = m->tcf_action;
346 	p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
347 	opt.m_action = p->tcfm_action;
348 
349 	if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
350 		goto nla_put_failure;
351 
352 	if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
353 	    nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
354 		goto nla_put_failure;
355 
356 	if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
357 	    nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
358 		goto nla_put_failure;
359 
360 	if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
361 		goto nla_put_failure;
362 
363 	if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
364 	    nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
365 		goto nla_put_failure;
366 
367 	if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
368 		goto nla_put_failure;
369 
370 	tcf_tm_dump(&t, &m->tcf_tm);
371 
372 	if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
373 		goto nla_put_failure;
374 
375 	spin_unlock_bh(&m->tcf_lock);
376 
377 	return skb->len;
378 
379 nla_put_failure:
380 	spin_unlock_bh(&m->tcf_lock);
381 	nlmsg_trim(skb, b);
382 	return -EMSGSIZE;
383 }
384 
tcf_mpls_offload_act_setup(struct tc_action * act,void * entry_data,u32 * index_inc,bool bind,struct netlink_ext_ack * extack)385 static int tcf_mpls_offload_act_setup(struct tc_action *act, void *entry_data,
386 				      u32 *index_inc, bool bind,
387 				      struct netlink_ext_ack *extack)
388 {
389 	if (bind) {
390 		struct flow_action_entry *entry = entry_data;
391 
392 		switch (tcf_mpls_action(act)) {
393 		case TCA_MPLS_ACT_PUSH:
394 			entry->id = FLOW_ACTION_MPLS_PUSH;
395 			entry->mpls_push.proto = tcf_mpls_proto(act);
396 			entry->mpls_push.label = tcf_mpls_label(act);
397 			entry->mpls_push.tc = tcf_mpls_tc(act);
398 			entry->mpls_push.bos = tcf_mpls_bos(act);
399 			entry->mpls_push.ttl = tcf_mpls_ttl(act);
400 			break;
401 		case TCA_MPLS_ACT_POP:
402 			entry->id = FLOW_ACTION_MPLS_POP;
403 			entry->mpls_pop.proto = tcf_mpls_proto(act);
404 			break;
405 		case TCA_MPLS_ACT_MODIFY:
406 			entry->id = FLOW_ACTION_MPLS_MANGLE;
407 			entry->mpls_mangle.label = tcf_mpls_label(act);
408 			entry->mpls_mangle.tc = tcf_mpls_tc(act);
409 			entry->mpls_mangle.bos = tcf_mpls_bos(act);
410 			entry->mpls_mangle.ttl = tcf_mpls_ttl(act);
411 			break;
412 		case TCA_MPLS_ACT_DEC_TTL:
413 			NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"dec_ttl\" option is used");
414 			return -EOPNOTSUPP;
415 		case TCA_MPLS_ACT_MAC_PUSH:
416 			NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"mac_push\" option is used");
417 			return -EOPNOTSUPP;
418 		default:
419 			NL_SET_ERR_MSG_MOD(extack, "Unsupported MPLS mode offload");
420 			return -EOPNOTSUPP;
421 		}
422 		*index_inc = 1;
423 	} else {
424 		struct flow_offload_action *fl_action = entry_data;
425 
426 		switch (tcf_mpls_action(act)) {
427 		case TCA_MPLS_ACT_PUSH:
428 			fl_action->id = FLOW_ACTION_MPLS_PUSH;
429 			break;
430 		case TCA_MPLS_ACT_POP:
431 			fl_action->id = FLOW_ACTION_MPLS_POP;
432 			break;
433 		case TCA_MPLS_ACT_MODIFY:
434 			fl_action->id = FLOW_ACTION_MPLS_MANGLE;
435 			break;
436 		default:
437 			return -EOPNOTSUPP;
438 		}
439 	}
440 
441 	return 0;
442 }
443 
444 static struct tc_action_ops act_mpls_ops = {
445 	.kind		=	"mpls",
446 	.id		=	TCA_ID_MPLS,
447 	.owner		=	THIS_MODULE,
448 	.act		=	tcf_mpls_act,
449 	.dump		=	tcf_mpls_dump,
450 	.init		=	tcf_mpls_init,
451 	.cleanup	=	tcf_mpls_cleanup,
452 	.offload_act_setup =	tcf_mpls_offload_act_setup,
453 	.size		=	sizeof(struct tcf_mpls),
454 };
455 
mpls_init_net(struct net * net)456 static __net_init int mpls_init_net(struct net *net)
457 {
458 	struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
459 
460 	return tc_action_net_init(net, tn, &act_mpls_ops);
461 }
462 
mpls_exit_net(struct list_head * net_list)463 static void __net_exit mpls_exit_net(struct list_head *net_list)
464 {
465 	tc_action_net_exit(net_list, act_mpls_ops.net_id);
466 }
467 
468 static struct pernet_operations mpls_net_ops = {
469 	.init = mpls_init_net,
470 	.exit_batch = mpls_exit_net,
471 	.id   = &act_mpls_ops.net_id,
472 	.size = sizeof(struct tc_action_net),
473 };
474 
mpls_init_module(void)475 static int __init mpls_init_module(void)
476 {
477 	return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
478 }
479 
mpls_cleanup_module(void)480 static void __exit mpls_cleanup_module(void)
481 {
482 	tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
483 }
484 
485 module_init(mpls_init_module);
486 module_exit(mpls_cleanup_module);
487 
488 MODULE_SOFTDEP("post: mpls_gso");
489 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
490 MODULE_LICENSE("GPL");
491 MODULE_DESCRIPTION("MPLS manipulation actions");
492