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  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		err = seg6_hmac_info_del(net, hmackeyid);
126
127		goto out_unlock;
128	}
129
130	if (!info->attrs[SEG6_ATTR_SECRET]) {
131		err = -EINVAL;
132		goto out_unlock;
133	}
134
135	if (hinfo) {
136		err = seg6_hmac_info_del(net, hmackeyid);
137		if (err)
138			goto out_unlock;
139	}
140
141	secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
142
143	hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
144	if (!hinfo) {
145		err = -ENOMEM;
146		goto out_unlock;
147	}
148
149	memcpy(hinfo->secret, secret, slen);
150	hinfo->slen = slen;
151	hinfo->alg_id = algid;
152	hinfo->hmackeyid = hmackeyid;
153
154	err = seg6_hmac_info_add(net, hmackeyid, hinfo);
155	if (err)
156		kfree(hinfo);
157
158out_unlock:
159	mutex_unlock(&sdata->lock);
160	return err;
161}
162
163#else
164
165static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
166{
167	return -ENOTSUPP;
168}
169
170#endif
171
172static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
173{
174	struct net *net = genl_info_net(info);
175	struct in6_addr *val, *t_old, *t_new;
176	struct seg6_pernet_data *sdata;
177
178	sdata = seg6_pernet(net);
179
180	if (!info->attrs[SEG6_ATTR_DST])
181		return -EINVAL;
182
183	val = nla_data(info->attrs[SEG6_ATTR_DST]);
184	t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
185	if (!t_new)
186		return -ENOMEM;
187
188	mutex_lock(&sdata->lock);
189
190	t_old = sdata->tun_src;
191	rcu_assign_pointer(sdata->tun_src, t_new);
192
193	mutex_unlock(&sdata->lock);
194
195	synchronize_net();
196	kfree(t_old);
197
198	return 0;
199}
200
201static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
202{
203	struct net *net = genl_info_net(info);
204	struct in6_addr *tun_src;
205	struct sk_buff *msg;
206	void *hdr;
207
208	msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
209	if (!msg)
210		return -ENOMEM;
211
212	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
213			  &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
214	if (!hdr)
215		goto free_msg;
216
217	rcu_read_lock();
218	tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
219
220	if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
221		goto nla_put_failure;
222
223	rcu_read_unlock();
224
225	genlmsg_end(msg, hdr);
226	return genlmsg_reply(msg, info);
227
228nla_put_failure:
229	rcu_read_unlock();
230free_msg:
231	nlmsg_free(msg);
232	return -ENOMEM;
233}
234
235#ifdef CONFIG_IPV6_SEG6_HMAC
236
237static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
238				 struct sk_buff *msg)
239{
240	if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
241	    nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
242	    nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
243	    nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
244		return -1;
245
246	return 0;
247}
248
249static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
250					u32 portid, u32 seq, u32 flags,
251					struct sk_buff *skb, u8 cmd)
252{
253	void *hdr;
254
255	hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
256	if (!hdr)
257		return -ENOMEM;
258
259	if (__seg6_hmac_fill_info(hinfo, skb) < 0)
260		goto nla_put_failure;
261
262	genlmsg_end(skb, hdr);
263	return 0;
264
265nla_put_failure:
266	genlmsg_cancel(skb, hdr);
267	return -EMSGSIZE;
268}
269
270static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
271{
272	struct net *net = sock_net(cb->skb->sk);
273	struct seg6_pernet_data *sdata;
274	struct rhashtable_iter *iter;
275
276	sdata = seg6_pernet(net);
277	iter = (struct rhashtable_iter *)cb->args[0];
278
279	if (!iter) {
280		iter = kmalloc(sizeof(*iter), GFP_KERNEL);
281		if (!iter)
282			return -ENOMEM;
283
284		cb->args[0] = (long)iter;
285	}
286
287	rhashtable_walk_enter(&sdata->hmac_infos, iter);
288
289	return 0;
290}
291
292static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
293{
294	struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
295
296	rhashtable_walk_exit(iter);
297
298	kfree(iter);
299
300	return 0;
301}
302
303static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
304{
305	struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
306	struct seg6_hmac_info *hinfo;
307	int ret;
308
309	rhashtable_walk_start(iter);
310
311	for (;;) {
312		hinfo = rhashtable_walk_next(iter);
313
314		if (IS_ERR(hinfo)) {
315			if (PTR_ERR(hinfo) == -EAGAIN)
316				continue;
317			ret = PTR_ERR(hinfo);
318			goto done;
319		} else if (!hinfo) {
320			break;
321		}
322
323		ret = __seg6_genl_dumphmac_element(hinfo,
324						   NETLINK_CB(cb->skb).portid,
325						   cb->nlh->nlmsg_seq,
326						   NLM_F_MULTI,
327						   skb, SEG6_CMD_DUMPHMAC);
328		if (ret)
329			goto done;
330	}
331
332	ret = skb->len;
333
334done:
335	rhashtable_walk_stop(iter);
336	return ret;
337}
338
339#else
340
341static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
342{
343	return 0;
344}
345
346static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
347{
348	return 0;
349}
350
351static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
352{
353	return -ENOTSUPP;
354}
355
356#endif
357
358static int __net_init seg6_net_init(struct net *net)
359{
360	struct seg6_pernet_data *sdata;
361
362	sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
363	if (!sdata)
364		return -ENOMEM;
365
366	mutex_init(&sdata->lock);
367
368	sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
369	if (!sdata->tun_src) {
370		kfree(sdata);
371		return -ENOMEM;
372	}
373
374	net->ipv6.seg6_data = sdata;
375
376#ifdef CONFIG_IPV6_SEG6_HMAC
377	seg6_hmac_net_init(net);
378#endif
379
380	return 0;
381}
382
383static void __net_exit seg6_net_exit(struct net *net)
384{
385	struct seg6_pernet_data *sdata = seg6_pernet(net);
386
387#ifdef CONFIG_IPV6_SEG6_HMAC
388	seg6_hmac_net_exit(net);
389#endif
390
391	kfree(sdata->tun_src);
392	kfree(sdata);
393}
394
395static struct pernet_operations ip6_segments_ops = {
396	.init = seg6_net_init,
397	.exit = seg6_net_exit,
398};
399
400static const struct genl_ops seg6_genl_ops[] = {
401	{
402		.cmd	= SEG6_CMD_SETHMAC,
403		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
404		.doit	= seg6_genl_sethmac,
405		.flags	= GENL_ADMIN_PERM,
406	},
407	{
408		.cmd	= SEG6_CMD_DUMPHMAC,
409		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
410		.start	= seg6_genl_dumphmac_start,
411		.dumpit	= seg6_genl_dumphmac,
412		.done	= seg6_genl_dumphmac_done,
413		.flags	= GENL_ADMIN_PERM,
414	},
415	{
416		.cmd	= SEG6_CMD_SET_TUNSRC,
417		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
418		.doit	= seg6_genl_set_tunsrc,
419		.flags	= GENL_ADMIN_PERM,
420	},
421	{
422		.cmd	= SEG6_CMD_GET_TUNSRC,
423		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
424		.doit	= seg6_genl_get_tunsrc,
425		.flags	= GENL_ADMIN_PERM,
426	},
427};
428
429static struct genl_family seg6_genl_family __ro_after_init = {
430	.hdrsize	= 0,
431	.name		= SEG6_GENL_NAME,
432	.version	= SEG6_GENL_VERSION,
433	.maxattr	= SEG6_ATTR_MAX,
434	.policy = seg6_genl_policy,
435	.netnsok	= true,
436	.parallel_ops	= true,
437	.ops		= seg6_genl_ops,
438	.n_ops		= ARRAY_SIZE(seg6_genl_ops),
439	.module		= THIS_MODULE,
440};
441
442int __init seg6_init(void)
443{
444	int err;
445
446	err = genl_register_family(&seg6_genl_family);
447	if (err)
448		goto out;
449
450	err = register_pernet_subsys(&ip6_segments_ops);
451	if (err)
452		goto out_unregister_genl;
453
454#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
455	err = seg6_iptunnel_init();
456	if (err)
457		goto out_unregister_pernet;
458
459	err = seg6_local_init();
460	if (err)
461		goto out_unregister_pernet;
462#endif
463
464#ifdef CONFIG_IPV6_SEG6_HMAC
465	err = seg6_hmac_init();
466	if (err)
467		goto out_unregister_iptun;
468#endif
469
470	pr_info("Segment Routing with IPv6\n");
471
472out:
473	return err;
474#ifdef CONFIG_IPV6_SEG6_HMAC
475out_unregister_iptun:
476#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
477	seg6_local_exit();
478	seg6_iptunnel_exit();
479#endif
480#endif
481#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
482out_unregister_pernet:
483	unregister_pernet_subsys(&ip6_segments_ops);
484#endif
485out_unregister_genl:
486	genl_unregister_family(&seg6_genl_family);
487	goto out;
488}
489
490void seg6_exit(void)
491{
492#ifdef CONFIG_IPV6_SEG6_HMAC
493	seg6_hmac_exit();
494#endif
495#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
496	seg6_iptunnel_exit();
497#endif
498	unregister_pernet_subsys(&ip6_segments_ops);
499	genl_unregister_family(&seg6_genl_family);
500}