xref: /openbmc/linux/net/sched/act_mpls.c (revision 8795a739)
1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Netronome Systems, Inc. */
3 
4 #include <linux/init.h>
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/mpls.h>
8 #include <linux/rtnetlink.h>
9 #include <linux/skbuff.h>
10 #include <linux/tc_act/tc_mpls.h>
11 #include <net/mpls.h>
12 #include <net/netlink.h>
13 #include <net/pkt_sched.h>
14 #include <net/pkt_cls.h>
15 #include <net/tc_act/tc_mpls.h>
16 
17 static unsigned int mpls_net_id;
18 static struct tc_action_ops act_mpls_ops;
19 
20 #define ACT_MPLS_TTL_DEFAULT	255
21 
22 static __be32 tcf_mpls_get_lse(struct mpls_shim_hdr *lse,
23 			       struct tcf_mpls_params *p, bool set_bos)
24 {
25 	u32 new_lse = 0;
26 
27 	if (lse)
28 		new_lse = be32_to_cpu(lse->label_stack_entry);
29 
30 	if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET) {
31 		new_lse &= ~MPLS_LS_LABEL_MASK;
32 		new_lse |= p->tcfm_label << MPLS_LS_LABEL_SHIFT;
33 	}
34 	if (p->tcfm_ttl) {
35 		new_lse &= ~MPLS_LS_TTL_MASK;
36 		new_lse |= p->tcfm_ttl << MPLS_LS_TTL_SHIFT;
37 	}
38 	if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET) {
39 		new_lse &= ~MPLS_LS_TC_MASK;
40 		new_lse |= p->tcfm_tc << MPLS_LS_TC_SHIFT;
41 	}
42 	if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET) {
43 		new_lse &= ~MPLS_LS_S_MASK;
44 		new_lse |= p->tcfm_bos << MPLS_LS_S_SHIFT;
45 	} else if (set_bos) {
46 		new_lse |= 1 << MPLS_LS_S_SHIFT;
47 	}
48 
49 	return cpu_to_be32(new_lse);
50 }
51 
52 static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
53 			struct tcf_result *res)
54 {
55 	struct tcf_mpls *m = to_mpls(a);
56 	struct tcf_mpls_params *p;
57 	__be32 new_lse;
58 	int ret;
59 
60 	tcf_lastuse_update(&m->tcf_tm);
61 	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
62 
63 	/* Ensure 'data' points at mac_header prior calling mpls manipulating
64 	 * functions.
65 	 */
66 	if (skb_at_tc_ingress(skb))
67 		skb_push_rcsum(skb, skb->mac_len);
68 
69 	ret = READ_ONCE(m->tcf_action);
70 
71 	p = rcu_dereference_bh(m->mpls_p);
72 
73 	switch (p->tcfm_action) {
74 	case TCA_MPLS_ACT_POP:
75 		if (skb_mpls_pop(skb, p->tcfm_proto))
76 			goto drop;
77 		break;
78 	case TCA_MPLS_ACT_PUSH:
79 		new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb->protocol));
80 		if (skb_mpls_push(skb, new_lse, p->tcfm_proto))
81 			goto drop;
82 		break;
83 	case TCA_MPLS_ACT_MODIFY:
84 		new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
85 		if (skb_mpls_update_lse(skb, new_lse))
86 			goto drop;
87 		break;
88 	case TCA_MPLS_ACT_DEC_TTL:
89 		if (skb_mpls_dec_ttl(skb))
90 			goto drop;
91 		break;
92 	}
93 
94 	if (skb_at_tc_ingress(skb))
95 		skb_pull_rcsum(skb, skb->mac_len);
96 
97 	return ret;
98 
99 drop:
100 	qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
101 	return TC_ACT_SHOT;
102 }
103 
104 static int valid_label(const struct nlattr *attr,
105 		       struct netlink_ext_ack *extack)
106 {
107 	const u32 *label = nla_data(attr);
108 
109 	if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
110 		NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
111 		return -EINVAL;
112 	}
113 
114 	return 0;
115 }
116 
117 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
118 	[TCA_MPLS_UNSPEC]	= { .strict_start_type = TCA_MPLS_UNSPEC + 1 },
119 	[TCA_MPLS_PARMS]	= NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
120 	[TCA_MPLS_PROTO]	= { .type = NLA_U16 },
121 	[TCA_MPLS_LABEL]	= NLA_POLICY_VALIDATE_FN(NLA_U32, valid_label),
122 	[TCA_MPLS_TC]		= NLA_POLICY_RANGE(NLA_U8, 0, 7),
123 	[TCA_MPLS_TTL]		= NLA_POLICY_MIN(NLA_U8, 1),
124 	[TCA_MPLS_BOS]		= NLA_POLICY_RANGE(NLA_U8, 0, 1),
125 };
126 
127 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
128 			 struct nlattr *est, struct tc_action **a,
129 			 int ovr, int bind, bool rtnl_held,
130 			 struct tcf_proto *tp, struct netlink_ext_ack *extack)
131 {
132 	struct tc_action_net *tn = net_generic(net, mpls_net_id);
133 	struct nlattr *tb[TCA_MPLS_MAX + 1];
134 	struct tcf_chain *goto_ch = NULL;
135 	struct tcf_mpls_params *p;
136 	struct tc_mpls *parm;
137 	bool exists = false;
138 	struct tcf_mpls *m;
139 	int ret = 0, err;
140 	u8 mpls_ttl = 0;
141 	u32 index;
142 
143 	if (!nla) {
144 		NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
145 		return -EINVAL;
146 	}
147 
148 	err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
149 	if (err < 0)
150 		return err;
151 
152 	if (!tb[TCA_MPLS_PARMS]) {
153 		NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
154 		return -EINVAL;
155 	}
156 	parm = nla_data(tb[TCA_MPLS_PARMS]);
157 	index = parm->index;
158 
159 	/* Verify parameters against action type. */
160 	switch (parm->m_action) {
161 	case TCA_MPLS_ACT_POP:
162 		if (!tb[TCA_MPLS_PROTO]) {
163 			NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
164 			return -EINVAL;
165 		}
166 		if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
167 			NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
168 			return -EINVAL;
169 		}
170 		if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
171 		    tb[TCA_MPLS_BOS]) {
172 			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
173 			return -EINVAL;
174 		}
175 		break;
176 	case TCA_MPLS_ACT_DEC_TTL:
177 		if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
178 		    tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
179 			NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
180 			return -EINVAL;
181 		}
182 		break;
183 	case TCA_MPLS_ACT_PUSH:
184 		if (!tb[TCA_MPLS_LABEL]) {
185 			NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
186 			return -EINVAL;
187 		}
188 		if (tb[TCA_MPLS_PROTO] &&
189 		    !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
190 			NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
191 			return -EPROTONOSUPPORT;
192 		}
193 		/* Push needs a TTL - if not specified, set a default value. */
194 		if (!tb[TCA_MPLS_TTL]) {
195 #if IS_ENABLED(CONFIG_MPLS)
196 			mpls_ttl = net->mpls.default_ttl ?
197 				   net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
198 #else
199 			mpls_ttl = ACT_MPLS_TTL_DEFAULT;
200 #endif
201 		}
202 		break;
203 	case TCA_MPLS_ACT_MODIFY:
204 		if (tb[TCA_MPLS_PROTO]) {
205 			NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
206 			return -EINVAL;
207 		}
208 		break;
209 	default:
210 		NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
211 		return -EINVAL;
212 	}
213 
214 	err = tcf_idr_check_alloc(tn, &index, a, bind);
215 	if (err < 0)
216 		return err;
217 	exists = err;
218 	if (exists && bind)
219 		return 0;
220 
221 	if (!exists) {
222 		ret = tcf_idr_create(tn, index, est, a,
223 				     &act_mpls_ops, bind, true);
224 		if (ret) {
225 			tcf_idr_cleanup(tn, index);
226 			return ret;
227 		}
228 
229 		ret = ACT_P_CREATED;
230 	} else if (!ovr) {
231 		tcf_idr_release(*a, bind);
232 		return -EEXIST;
233 	}
234 
235 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
236 	if (err < 0)
237 		goto release_idr;
238 
239 	m = to_mpls(*a);
240 
241 	p = kzalloc(sizeof(*p), GFP_KERNEL);
242 	if (!p) {
243 		err = -ENOMEM;
244 		goto put_chain;
245 	}
246 
247 	p->tcfm_action = parm->m_action;
248 	p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
249 					     ACT_MPLS_LABEL_NOT_SET;
250 	p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
251 				       ACT_MPLS_TC_NOT_SET;
252 	p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
253 					 mpls_ttl;
254 	p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
255 					 ACT_MPLS_BOS_NOT_SET;
256 	p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
257 					     htons(ETH_P_MPLS_UC);
258 
259 	spin_lock_bh(&m->tcf_lock);
260 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
261 	rcu_swap_protected(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
262 	spin_unlock_bh(&m->tcf_lock);
263 
264 	if (goto_ch)
265 		tcf_chain_put_by_act(goto_ch);
266 	if (p)
267 		kfree_rcu(p, rcu);
268 
269 	if (ret == ACT_P_CREATED)
270 		tcf_idr_insert(tn, *a);
271 	return ret;
272 put_chain:
273 	if (goto_ch)
274 		tcf_chain_put_by_act(goto_ch);
275 release_idr:
276 	tcf_idr_release(*a, bind);
277 	return err;
278 }
279 
280 static void tcf_mpls_cleanup(struct tc_action *a)
281 {
282 	struct tcf_mpls *m = to_mpls(a);
283 	struct tcf_mpls_params *p;
284 
285 	p = rcu_dereference_protected(m->mpls_p, 1);
286 	if (p)
287 		kfree_rcu(p, rcu);
288 }
289 
290 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
291 			 int bind, int ref)
292 {
293 	unsigned char *b = skb_tail_pointer(skb);
294 	struct tcf_mpls *m = to_mpls(a);
295 	struct tcf_mpls_params *p;
296 	struct tc_mpls opt = {
297 		.index    = m->tcf_index,
298 		.refcnt   = refcount_read(&m->tcf_refcnt) - ref,
299 		.bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
300 	};
301 	struct tcf_t t;
302 
303 	spin_lock_bh(&m->tcf_lock);
304 	opt.action = m->tcf_action;
305 	p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
306 	opt.m_action = p->tcfm_action;
307 
308 	if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
309 		goto nla_put_failure;
310 
311 	if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
312 	    nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
313 		goto nla_put_failure;
314 
315 	if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
316 	    nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
317 		goto nla_put_failure;
318 
319 	if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
320 		goto nla_put_failure;
321 
322 	if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
323 	    nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
324 		goto nla_put_failure;
325 
326 	if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
327 		goto nla_put_failure;
328 
329 	tcf_tm_dump(&t, &m->tcf_tm);
330 
331 	if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
332 		goto nla_put_failure;
333 
334 	spin_unlock_bh(&m->tcf_lock);
335 
336 	return skb->len;
337 
338 nla_put_failure:
339 	spin_unlock_bh(&m->tcf_lock);
340 	nlmsg_trim(skb, b);
341 	return -EMSGSIZE;
342 }
343 
344 static int tcf_mpls_walker(struct net *net, struct sk_buff *skb,
345 			   struct netlink_callback *cb, int type,
346 			   const struct tc_action_ops *ops,
347 			   struct netlink_ext_ack *extack)
348 {
349 	struct tc_action_net *tn = net_generic(net, mpls_net_id);
350 
351 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
352 }
353 
354 static int tcf_mpls_search(struct net *net, struct tc_action **a, u32 index)
355 {
356 	struct tc_action_net *tn = net_generic(net, mpls_net_id);
357 
358 	return tcf_idr_search(tn, a, index);
359 }
360 
361 static struct tc_action_ops act_mpls_ops = {
362 	.kind		=	"mpls",
363 	.id		=	TCA_ID_MPLS,
364 	.owner		=	THIS_MODULE,
365 	.act		=	tcf_mpls_act,
366 	.dump		=	tcf_mpls_dump,
367 	.init		=	tcf_mpls_init,
368 	.cleanup	=	tcf_mpls_cleanup,
369 	.walk		=	tcf_mpls_walker,
370 	.lookup		=	tcf_mpls_search,
371 	.size		=	sizeof(struct tcf_mpls),
372 };
373 
374 static __net_init int mpls_init_net(struct net *net)
375 {
376 	struct tc_action_net *tn = net_generic(net, mpls_net_id);
377 
378 	return tc_action_net_init(net, tn, &act_mpls_ops);
379 }
380 
381 static void __net_exit mpls_exit_net(struct list_head *net_list)
382 {
383 	tc_action_net_exit(net_list, mpls_net_id);
384 }
385 
386 static struct pernet_operations mpls_net_ops = {
387 	.init = mpls_init_net,
388 	.exit_batch = mpls_exit_net,
389 	.id   = &mpls_net_id,
390 	.size = sizeof(struct tc_action_net),
391 };
392 
393 static int __init mpls_init_module(void)
394 {
395 	return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
396 }
397 
398 static void __exit mpls_cleanup_module(void)
399 {
400 	tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
401 }
402 
403 module_init(mpls_init_module);
404 module_exit(mpls_cleanup_module);
405 
406 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
407 MODULE_LICENSE("GPL");
408 MODULE_DESCRIPTION("MPLS manipulation actions");
409