xref: /kernel/linux/linux-5.10/net/ipv6/seg6.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  SR-IPv6 implementation
4 *
5 *  Author:
6 *  David Lebrun <david.lebrun@uclouvain.be>
7 */
8
9#include <linux/errno.h>
10#include <linux/types.h>
11#include <linux/socket.h>
12#include <linux/net.h>
13#include <linux/in6.h>
14#include <linux/slab.h>
15#include <linux/rhashtable.h>
16
17#include <net/ipv6.h>
18#include <net/protocol.h>
19
20#include <net/seg6.h>
21#include <net/genetlink.h>
22#include <linux/seg6.h>
23#include <linux/seg6_genl.h>
24#ifdef CONFIG_IPV6_SEG6_HMAC
25#include <net/seg6_hmac.h>
26#endif
27
28bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len, bool reduced)
29{
30	unsigned int tlv_offset;
31	int max_last_entry;
32	int trailing;
33
34	if (srh->type != IPV6_SRCRT_TYPE_4)
35		return false;
36
37	if (((srh->hdrlen + 1) << 3) != len)
38		return false;
39
40	if (!reduced && srh->segments_left > srh->first_segment) {
41		return false;
42	} else {
43		max_last_entry = (srh->hdrlen / 2) - 1;
44
45		if (srh->first_segment > max_last_entry)
46			return false;
47
48		if (srh->segments_left > srh->first_segment + 1)
49			return false;
50	}
51
52	tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
53
54	trailing = len - tlv_offset;
55	if (trailing < 0)
56		return false;
57
58	while (trailing) {
59		struct sr6_tlv *tlv;
60		unsigned int tlv_len;
61
62		if (trailing < sizeof(*tlv))
63			return false;
64
65		tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
66		tlv_len = sizeof(*tlv) + tlv->len;
67
68		trailing -= tlv_len;
69		if (trailing < 0)
70			return false;
71
72		tlv_offset += tlv_len;
73	}
74
75	return true;
76}
77
78static struct genl_family seg6_genl_family;
79
80static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
81	[SEG6_ATTR_DST]				= { .type = NLA_BINARY,
82		.len = sizeof(struct in6_addr) },
83	[SEG6_ATTR_DSTLEN]			= { .type = NLA_S32, },
84	[SEG6_ATTR_HMACKEYID]		= { .type = NLA_U32, },
85	[SEG6_ATTR_SECRET]			= { .type = NLA_BINARY, },
86	[SEG6_ATTR_SECRETLEN]		= { .type = NLA_U8, },
87	[SEG6_ATTR_ALGID]			= { .type = NLA_U8, },
88	[SEG6_ATTR_HMACINFO]		= { .type = NLA_NESTED, },
89};
90
91#ifdef CONFIG_IPV6_SEG6_HMAC
92
93static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
94{
95	struct net *net = genl_info_net(info);
96	struct seg6_pernet_data *sdata;
97	struct seg6_hmac_info *hinfo;
98	u32 hmackeyid;
99	char *secret;
100	int err = 0;
101	u8 algid;
102	u8 slen;
103
104	sdata = seg6_pernet(net);
105
106	if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
107	    !info->attrs[SEG6_ATTR_SECRETLEN] ||
108	    !info->attrs[SEG6_ATTR_ALGID])
109		return -EINVAL;
110
111	hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
112	slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
113	algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
114
115	if (hmackeyid == 0)
116		return -EINVAL;
117
118	if (slen > SEG6_HMAC_SECRET_LEN)
119		return -EINVAL;
120
121	mutex_lock(&sdata->lock);
122	hinfo = seg6_hmac_info_lookup(net, hmackeyid);
123
124	if (!slen) {
125		if (!hinfo)
126			err = -ENOENT;
127
128		err = seg6_hmac_info_del(net, hmackeyid);
129
130		goto out_unlock;
131	}
132
133	if (!info->attrs[SEG6_ATTR_SECRET]) {
134		err = -EINVAL;
135		goto out_unlock;
136	}
137
138	if (slen > nla_len(info->attrs[SEG6_ATTR_SECRET])) {
139		err = -EINVAL;
140		goto out_unlock;
141	}
142
143	if (hinfo) {
144		err = seg6_hmac_info_del(net, hmackeyid);
145		if (err)
146			goto out_unlock;
147	}
148
149	secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
150
151	hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
152	if (!hinfo) {
153		err = -ENOMEM;
154		goto out_unlock;
155	}
156
157	memcpy(hinfo->secret, secret, slen);
158	hinfo->slen = slen;
159	hinfo->alg_id = algid;
160	hinfo->hmackeyid = hmackeyid;
161
162	err = seg6_hmac_info_add(net, hmackeyid, hinfo);
163	if (err)
164		kfree(hinfo);
165
166out_unlock:
167	mutex_unlock(&sdata->lock);
168	return err;
169}
170
171#else
172
173static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
174{
175	return -ENOTSUPP;
176}
177
178#endif
179
180static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
181{
182	struct net *net = genl_info_net(info);
183	struct in6_addr *val, *t_old, *t_new;
184	struct seg6_pernet_data *sdata;
185
186	sdata = seg6_pernet(net);
187
188	if (!info->attrs[SEG6_ATTR_DST])
189		return -EINVAL;
190
191	val = nla_data(info->attrs[SEG6_ATTR_DST]);
192	t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
193	if (!t_new)
194		return -ENOMEM;
195
196	mutex_lock(&sdata->lock);
197
198	t_old = sdata->tun_src;
199	rcu_assign_pointer(sdata->tun_src, t_new);
200
201	mutex_unlock(&sdata->lock);
202
203	synchronize_net();
204	kfree(t_old);
205
206	return 0;
207}
208
209static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
210{
211	struct net *net = genl_info_net(info);
212	struct in6_addr *tun_src;
213	struct sk_buff *msg;
214	void *hdr;
215
216	msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
217	if (!msg)
218		return -ENOMEM;
219
220	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
221			  &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
222	if (!hdr)
223		goto free_msg;
224
225	rcu_read_lock();
226	tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
227
228	if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
229		goto nla_put_failure;
230
231	rcu_read_unlock();
232
233	genlmsg_end(msg, hdr);
234	return genlmsg_reply(msg, info);
235
236nla_put_failure:
237	rcu_read_unlock();
238free_msg:
239	nlmsg_free(msg);
240	return -ENOMEM;
241}
242
243#ifdef CONFIG_IPV6_SEG6_HMAC
244
245static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
246				 struct sk_buff *msg)
247{
248	if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
249	    nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
250	    nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
251	    nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
252		return -1;
253
254	return 0;
255}
256
257static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
258					u32 portid, u32 seq, u32 flags,
259					struct sk_buff *skb, u8 cmd)
260{
261	void *hdr;
262
263	hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
264	if (!hdr)
265		return -ENOMEM;
266
267	if (__seg6_hmac_fill_info(hinfo, skb) < 0)
268		goto nla_put_failure;
269
270	genlmsg_end(skb, hdr);
271	return 0;
272
273nla_put_failure:
274	genlmsg_cancel(skb, hdr);
275	return -EMSGSIZE;
276}
277
278static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
279{
280	struct net *net = sock_net(cb->skb->sk);
281	struct seg6_pernet_data *sdata;
282	struct rhashtable_iter *iter;
283
284	sdata = seg6_pernet(net);
285	iter = (struct rhashtable_iter *)cb->args[0];
286
287	if (!iter) {
288		iter = kmalloc(sizeof(*iter), GFP_KERNEL);
289		if (!iter)
290			return -ENOMEM;
291
292		cb->args[0] = (long)iter;
293	}
294
295	rhashtable_walk_enter(&sdata->hmac_infos, iter);
296
297	return 0;
298}
299
300static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
301{
302	struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
303
304	rhashtable_walk_exit(iter);
305
306	kfree(iter);
307
308	return 0;
309}
310
311static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
312{
313	struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
314	struct seg6_hmac_info *hinfo;
315	int ret;
316
317	rhashtable_walk_start(iter);
318
319	for (;;) {
320		hinfo = rhashtable_walk_next(iter);
321
322		if (IS_ERR(hinfo)) {
323			if (PTR_ERR(hinfo) == -EAGAIN)
324				continue;
325			ret = PTR_ERR(hinfo);
326			goto done;
327		} else if (!hinfo) {
328			break;
329		}
330
331		ret = __seg6_genl_dumphmac_element(hinfo,
332						   NETLINK_CB(cb->skb).portid,
333						   cb->nlh->nlmsg_seq,
334						   NLM_F_MULTI,
335						   skb, SEG6_CMD_DUMPHMAC);
336		if (ret)
337			goto done;
338	}
339
340	ret = skb->len;
341
342done:
343	rhashtable_walk_stop(iter);
344	return ret;
345}
346
347#else
348
349static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
350{
351	return 0;
352}
353
354static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
355{
356	return 0;
357}
358
359static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
360{
361	return -ENOTSUPP;
362}
363
364#endif
365
366static int __net_init seg6_net_init(struct net *net)
367{
368	struct seg6_pernet_data *sdata;
369
370	sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
371	if (!sdata)
372		return -ENOMEM;
373
374	mutex_init(&sdata->lock);
375
376	sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
377	if (!sdata->tun_src) {
378		kfree(sdata);
379		return -ENOMEM;
380	}
381
382	net->ipv6.seg6_data = sdata;
383
384#ifdef CONFIG_IPV6_SEG6_HMAC
385	seg6_hmac_net_init(net);
386#endif
387
388	return 0;
389}
390
391static void __net_exit seg6_net_exit(struct net *net)
392{
393	struct seg6_pernet_data *sdata = seg6_pernet(net);
394
395#ifdef CONFIG_IPV6_SEG6_HMAC
396	seg6_hmac_net_exit(net);
397#endif
398
399	kfree(sdata->tun_src);
400	kfree(sdata);
401}
402
403static struct pernet_operations ip6_segments_ops = {
404	.init = seg6_net_init,
405	.exit = seg6_net_exit,
406};
407
408static const struct genl_ops seg6_genl_ops[] = {
409	{
410		.cmd	= SEG6_CMD_SETHMAC,
411		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
412		.doit	= seg6_genl_sethmac,
413		.flags	= GENL_ADMIN_PERM,
414	},
415	{
416		.cmd	= SEG6_CMD_DUMPHMAC,
417		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
418		.start	= seg6_genl_dumphmac_start,
419		.dumpit	= seg6_genl_dumphmac,
420		.done	= seg6_genl_dumphmac_done,
421		.flags	= GENL_ADMIN_PERM,
422	},
423	{
424		.cmd	= SEG6_CMD_SET_TUNSRC,
425		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
426		.doit	= seg6_genl_set_tunsrc,
427		.flags	= GENL_ADMIN_PERM,
428	},
429	{
430		.cmd	= SEG6_CMD_GET_TUNSRC,
431		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
432		.doit	= seg6_genl_get_tunsrc,
433		.flags	= GENL_ADMIN_PERM,
434	},
435};
436
437static struct genl_family seg6_genl_family __ro_after_init = {
438	.hdrsize	= 0,
439	.name		= SEG6_GENL_NAME,
440	.version	= SEG6_GENL_VERSION,
441	.maxattr	= SEG6_ATTR_MAX,
442	.policy = seg6_genl_policy,
443	.netnsok	= true,
444	.parallel_ops	= true,
445	.ops		= seg6_genl_ops,
446	.n_ops		= ARRAY_SIZE(seg6_genl_ops),
447	.module		= THIS_MODULE,
448};
449
450int __init seg6_init(void)
451{
452	int err;
453
454	err = register_pernet_subsys(&ip6_segments_ops);
455	if (err)
456		goto out;
457
458	err = genl_register_family(&seg6_genl_family);
459	if (err)
460		goto out_unregister_pernet;
461
462#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
463	err = seg6_iptunnel_init();
464	if (err)
465		goto out_unregister_genl;
466
467	err = seg6_local_init();
468	if (err) {
469		seg6_iptunnel_exit();
470		goto out_unregister_genl;
471	}
472#endif
473
474#ifdef CONFIG_IPV6_SEG6_HMAC
475	err = seg6_hmac_init();
476	if (err)
477		goto out_unregister_iptun;
478#endif
479
480	pr_info("Segment Routing with IPv6\n");
481
482out:
483	return err;
484#ifdef CONFIG_IPV6_SEG6_HMAC
485out_unregister_iptun:
486#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
487	seg6_local_exit();
488	seg6_iptunnel_exit();
489#endif
490#endif
491#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
492out_unregister_genl:
493	genl_unregister_family(&seg6_genl_family);
494#endif
495out_unregister_pernet:
496	unregister_pernet_subsys(&ip6_segments_ops);
497	goto out;
498}
499
500void seg6_exit(void)
501{
502#ifdef CONFIG_IPV6_SEG6_HMAC
503	seg6_hmac_exit();
504#endif
505#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
506	seg6_iptunnel_exit();
507#endif
508	unregister_pernet_subsys(&ip6_segments_ops);
509	genl_unregister_family(&seg6_genl_family);
510}
511