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
 18static unsigned int mpls_net_id;
 19static struct tc_action_ops act_mpls_ops;
 20
 21#define ACT_MPLS_TTL_DEFAULT	255
 22
 23static __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
 53static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
 54			struct tcf_result *res)
 55{
 56	struct tcf_mpls *m = to_mpls(a);
 57	struct tcf_mpls_params *p;
 58	__be32 new_lse;
 59	int ret, mac_len;
 60
 61	tcf_lastuse_update(&m->tcf_tm);
 62	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
 63
 64	/* Ensure 'data' points at mac_header prior calling mpls manipulating
 65	 * functions.
 66	 */
 67	if (skb_at_tc_ingress(skb)) {
 68		skb_push_rcsum(skb, skb->mac_len);
 69		mac_len = skb->mac_len;
 70	} else {
 71		mac_len = skb_network_header(skb) - skb_mac_header(skb);
 72	}
 73
 74	ret = READ_ONCE(m->tcf_action);
 75
 76	p = rcu_dereference_bh(m->mpls_p);
 77
 78	switch (p->tcfm_action) {
 79	case TCA_MPLS_ACT_POP:
 80		if (skb_mpls_pop(skb, p->tcfm_proto, mac_len,
 81				 skb->dev && skb->dev->type == ARPHRD_ETHER))
 82			goto drop;
 83		break;
 84	case TCA_MPLS_ACT_PUSH:
 85		new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb_protocol(skb, true)));
 86		if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len,
 87				  skb->dev && skb->dev->type == ARPHRD_ETHER))
 88			goto drop;
 89		break;
 90	case TCA_MPLS_ACT_MODIFY:
 91		new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
 92		if (skb_mpls_update_lse(skb, new_lse))
 93			goto drop;
 94		break;
 95	case TCA_MPLS_ACT_DEC_TTL:
 96		if (skb_mpls_dec_ttl(skb))
 97			goto drop;
 98		break;
 99	}
100
101	if (skb_at_tc_ingress(skb))
102		skb_pull_rcsum(skb, skb->mac_len);
103
104	return ret;
105
106drop:
107	qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
108	return TC_ACT_SHOT;
109}
110
111static int valid_label(const struct nlattr *attr,
112		       struct netlink_ext_ack *extack)
113{
114	const u32 *label = nla_data(attr);
115
116	if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
117		NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
118		return -EINVAL;
119	}
120
121	return 0;
122}
123
124static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
125	[TCA_MPLS_PARMS]	= NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
126	[TCA_MPLS_PROTO]	= { .type = NLA_U16 },
127	[TCA_MPLS_LABEL]	= NLA_POLICY_VALIDATE_FN(NLA_U32, valid_label),
128	[TCA_MPLS_TC]		= NLA_POLICY_RANGE(NLA_U8, 0, 7),
129	[TCA_MPLS_TTL]		= NLA_POLICY_MIN(NLA_U8, 1),
130	[TCA_MPLS_BOS]		= NLA_POLICY_RANGE(NLA_U8, 0, 1),
131};
132
133static int tcf_mpls_init(struct net *net, struct nlattr *nla,
134			 struct nlattr *est, struct tc_action **a,
135			 int ovr, int bind, bool rtnl_held,
136			 struct tcf_proto *tp, u32 flags,
137			 struct netlink_ext_ack *extack)
138{
139	struct tc_action_net *tn = net_generic(net, mpls_net_id);
140	struct nlattr *tb[TCA_MPLS_MAX + 1];
141	struct tcf_chain *goto_ch = NULL;
142	struct tcf_mpls_params *p;
143	struct tc_mpls *parm;
144	bool exists = false;
145	struct tcf_mpls *m;
146	int ret = 0, err;
147	u8 mpls_ttl = 0;
148	u32 index;
149
150	if (!nla) {
151		NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
152		return -EINVAL;
153	}
154
155	err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
156	if (err < 0)
157		return err;
158
159	if (!tb[TCA_MPLS_PARMS]) {
160		NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
161		return -EINVAL;
162	}
163	parm = nla_data(tb[TCA_MPLS_PARMS]);
164	index = parm->index;
165
166	/* Verify parameters against action type. */
167	switch (parm->m_action) {
168	case TCA_MPLS_ACT_POP:
169		if (!tb[TCA_MPLS_PROTO]) {
170			NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
171			return -EINVAL;
172		}
173		if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
174			NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
175			return -EINVAL;
176		}
177		if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
178		    tb[TCA_MPLS_BOS]) {
179			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
180			return -EINVAL;
181		}
182		break;
183	case TCA_MPLS_ACT_DEC_TTL:
184		if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
185		    tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
186			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
187			return -EINVAL;
188		}
189		break;
190	case TCA_MPLS_ACT_PUSH:
191		if (!tb[TCA_MPLS_LABEL]) {
192			NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
193			return -EINVAL;
194		}
195		if (tb[TCA_MPLS_PROTO] &&
196		    !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
197			NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
198			return -EPROTONOSUPPORT;
199		}
200		/* Push needs a TTL - if not specified, set a default value. */
201		if (!tb[TCA_MPLS_TTL]) {
202#if IS_ENABLED(CONFIG_MPLS)
203			mpls_ttl = net->mpls.default_ttl ?
204				   net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
205#else
206			mpls_ttl = ACT_MPLS_TTL_DEFAULT;
207#endif
208		}
209		break;
210	case TCA_MPLS_ACT_MODIFY:
211		if (tb[TCA_MPLS_PROTO]) {
212			NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
213			return -EINVAL;
214		}
215		break;
216	default:
217		NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
218		return -EINVAL;
219	}
220
221	err = tcf_idr_check_alloc(tn, &index, a, bind);
222	if (err < 0)
223		return err;
224	exists = err;
225	if (exists && bind)
226		return 0;
227
228	if (!exists) {
229		ret = tcf_idr_create(tn, index, est, a,
230				     &act_mpls_ops, bind, true, 0);
231		if (ret) {
232			tcf_idr_cleanup(tn, index);
233			return ret;
234		}
235
236		ret = ACT_P_CREATED;
237	} else if (!ovr) {
238		tcf_idr_release(*a, bind);
239		return -EEXIST;
240	}
241
242	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
243	if (err < 0)
244		goto release_idr;
245
246	m = to_mpls(*a);
247
248	p = kzalloc(sizeof(*p), GFP_KERNEL);
249	if (!p) {
250		err = -ENOMEM;
251		goto put_chain;
252	}
253
254	p->tcfm_action = parm->m_action;
255	p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
256					     ACT_MPLS_LABEL_NOT_SET;
257	p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
258				       ACT_MPLS_TC_NOT_SET;
259	p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
260					 mpls_ttl;
261	p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
262					 ACT_MPLS_BOS_NOT_SET;
263	p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
264					     htons(ETH_P_MPLS_UC);
265
266	spin_lock_bh(&m->tcf_lock);
267	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
268	p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
269	spin_unlock_bh(&m->tcf_lock);
270
271	if (goto_ch)
272		tcf_chain_put_by_act(goto_ch);
273	if (p)
274		kfree_rcu(p, rcu);
275
276	return ret;
277put_chain:
278	if (goto_ch)
279		tcf_chain_put_by_act(goto_ch);
280release_idr:
281	tcf_idr_release(*a, bind);
282	return err;
283}
284
285static void tcf_mpls_cleanup(struct tc_action *a)
286{
287	struct tcf_mpls *m = to_mpls(a);
288	struct tcf_mpls_params *p;
289
290	p = rcu_dereference_protected(m->mpls_p, 1);
291	if (p)
292		kfree_rcu(p, rcu);
293}
294
295static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
296			 int bind, int ref)
297{
298	unsigned char *b = skb_tail_pointer(skb);
299	struct tcf_mpls *m = to_mpls(a);
300	struct tcf_mpls_params *p;
301	struct tc_mpls opt = {
302		.index    = m->tcf_index,
303		.refcnt   = refcount_read(&m->tcf_refcnt) - ref,
304		.bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
305	};
306	struct tcf_t t;
307
308	spin_lock_bh(&m->tcf_lock);
309	opt.action = m->tcf_action;
310	p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
311	opt.m_action = p->tcfm_action;
312
313	if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
314		goto nla_put_failure;
315
316	if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
317	    nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
318		goto nla_put_failure;
319
320	if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
321	    nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
322		goto nla_put_failure;
323
324	if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
325		goto nla_put_failure;
326
327	if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
328	    nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
329		goto nla_put_failure;
330
331	if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
332		goto nla_put_failure;
333
334	tcf_tm_dump(&t, &m->tcf_tm);
335
336	if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
337		goto nla_put_failure;
338
339	spin_unlock_bh(&m->tcf_lock);
340
341	return skb->len;
342
343nla_put_failure:
344	spin_unlock_bh(&m->tcf_lock);
345	nlmsg_trim(skb, b);
346	return -EMSGSIZE;
347}
348
349static int tcf_mpls_walker(struct net *net, struct sk_buff *skb,
350			   struct netlink_callback *cb, int type,
351			   const struct tc_action_ops *ops,
352			   struct netlink_ext_ack *extack)
353{
354	struct tc_action_net *tn = net_generic(net, mpls_net_id);
355
356	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
357}
358
359static int tcf_mpls_search(struct net *net, struct tc_action **a, u32 index)
360{
361	struct tc_action_net *tn = net_generic(net, mpls_net_id);
362
363	return tcf_idr_search(tn, a, index);
364}
365
366static struct tc_action_ops act_mpls_ops = {
367	.kind		=	"mpls",
368	.id		=	TCA_ID_MPLS,
369	.owner		=	THIS_MODULE,
370	.act		=	tcf_mpls_act,
371	.dump		=	tcf_mpls_dump,
372	.init		=	tcf_mpls_init,
373	.cleanup	=	tcf_mpls_cleanup,
374	.walk		=	tcf_mpls_walker,
375	.lookup		=	tcf_mpls_search,
376	.size		=	sizeof(struct tcf_mpls),
377};
378
379static __net_init int mpls_init_net(struct net *net)
380{
381	struct tc_action_net *tn = net_generic(net, mpls_net_id);
382
383	return tc_action_net_init(net, tn, &act_mpls_ops);
384}
385
386static void __net_exit mpls_exit_net(struct list_head *net_list)
387{
388	tc_action_net_exit(net_list, mpls_net_id);
389}
390
391static struct pernet_operations mpls_net_ops = {
392	.init = mpls_init_net,
393	.exit_batch = mpls_exit_net,
394	.id   = &mpls_net_id,
395	.size = sizeof(struct tc_action_net),
396};
397
398static int __init mpls_init_module(void)
399{
400	return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
401}
402
403static void __exit mpls_cleanup_module(void)
404{
405	tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
406}
407
408module_init(mpls_init_module);
409module_exit(mpls_cleanup_module);
410
411MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
412MODULE_LICENSE("GPL");
413MODULE_DESCRIPTION("MPLS manipulation actions");