1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Management Component Transport Protocol (MCTP) - device implementation.
4 *
5 * Copyright (c) 2021 Code Construct
6 * Copyright (c) 2021 Google
7 */
8
9 #include <linux/if_arp.h>
10 #include <linux/if_link.h>
11 #include <linux/mctp.h>
12 #include <linux/netdevice.h>
13 #include <linux/rcupdate.h>
14 #include <linux/rtnetlink.h>
15
16 #include <net/addrconf.h>
17 #include <net/netlink.h>
18 #include <net/mctp.h>
19 #include <net/mctpdevice.h>
20 #include <net/sock.h>
21
22 struct mctp_dump_cb {
23 int h;
24 int idx;
25 size_t a_idx;
26 };
27
28 /* unlocked: caller must hold rcu_read_lock.
29 * Returned mctp_dev has its refcount incremented, or NULL if unset.
30 */
__mctp_dev_get(const struct net_device * dev)31 struct mctp_dev *__mctp_dev_get(const struct net_device *dev)
32 {
33 struct mctp_dev *mdev = rcu_dereference(dev->mctp_ptr);
34
35 /* RCU guarantees that any mdev is still live.
36 * Zero refcount implies a pending free, return NULL.
37 */
38 if (mdev)
39 if (!refcount_inc_not_zero(&mdev->refs))
40 return NULL;
41 return mdev;
42 }
43
44 /* Returned mctp_dev does not have refcount incremented. The returned pointer
45 * remains live while rtnl_lock is held, as that prevents mctp_unregister()
46 */
mctp_dev_get_rtnl(const struct net_device * dev)47 struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev)
48 {
49 return rtnl_dereference(dev->mctp_ptr);
50 }
51
mctp_addrinfo_size(void)52 static int mctp_addrinfo_size(void)
53 {
54 return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
55 + nla_total_size(1) // IFA_LOCAL
56 + nla_total_size(1) // IFA_ADDRESS
57 ;
58 }
59
60 /* flag should be NLM_F_MULTI for dump calls */
mctp_fill_addrinfo(struct sk_buff * skb,struct mctp_dev * mdev,mctp_eid_t eid,int msg_type,u32 portid,u32 seq,int flag)61 static int mctp_fill_addrinfo(struct sk_buff *skb,
62 struct mctp_dev *mdev, mctp_eid_t eid,
63 int msg_type, u32 portid, u32 seq, int flag)
64 {
65 struct ifaddrmsg *hdr;
66 struct nlmsghdr *nlh;
67
68 nlh = nlmsg_put(skb, portid, seq,
69 msg_type, sizeof(*hdr), flag);
70 if (!nlh)
71 return -EMSGSIZE;
72
73 hdr = nlmsg_data(nlh);
74 hdr->ifa_family = AF_MCTP;
75 hdr->ifa_prefixlen = 0;
76 hdr->ifa_flags = 0;
77 hdr->ifa_scope = 0;
78 hdr->ifa_index = mdev->dev->ifindex;
79
80 if (nla_put_u8(skb, IFA_LOCAL, eid))
81 goto cancel;
82
83 if (nla_put_u8(skb, IFA_ADDRESS, eid))
84 goto cancel;
85
86 nlmsg_end(skb, nlh);
87
88 return 0;
89
90 cancel:
91 nlmsg_cancel(skb, nlh);
92 return -EMSGSIZE;
93 }
94
mctp_dump_dev_addrinfo(struct mctp_dev * mdev,struct sk_buff * skb,struct netlink_callback * cb)95 static int mctp_dump_dev_addrinfo(struct mctp_dev *mdev, struct sk_buff *skb,
96 struct netlink_callback *cb)
97 {
98 struct mctp_dump_cb *mcb = (void *)cb->ctx;
99 u32 portid, seq;
100 int rc = 0;
101
102 portid = NETLINK_CB(cb->skb).portid;
103 seq = cb->nlh->nlmsg_seq;
104 for (; mcb->a_idx < mdev->num_addrs; mcb->a_idx++) {
105 rc = mctp_fill_addrinfo(skb, mdev, mdev->addrs[mcb->a_idx],
106 RTM_NEWADDR, portid, seq, NLM_F_MULTI);
107 if (rc < 0)
108 break;
109 }
110
111 return rc;
112 }
113
mctp_dump_addrinfo(struct sk_buff * skb,struct netlink_callback * cb)114 static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
115 {
116 struct mctp_dump_cb *mcb = (void *)cb->ctx;
117 struct net *net = sock_net(skb->sk);
118 struct hlist_head *head;
119 struct net_device *dev;
120 struct ifaddrmsg *hdr;
121 struct mctp_dev *mdev;
122 int ifindex;
123 int idx = 0, rc;
124
125 hdr = nlmsg_data(cb->nlh);
126 // filter by ifindex if requested
127 ifindex = hdr->ifa_index;
128
129 rcu_read_lock();
130 for (; mcb->h < NETDEV_HASHENTRIES; mcb->h++, mcb->idx = 0) {
131 idx = 0;
132 head = &net->dev_index_head[mcb->h];
133 hlist_for_each_entry_rcu(dev, head, index_hlist) {
134 if (idx >= mcb->idx &&
135 (ifindex == 0 || ifindex == dev->ifindex)) {
136 mdev = __mctp_dev_get(dev);
137 if (mdev) {
138 rc = mctp_dump_dev_addrinfo(mdev,
139 skb, cb);
140 mctp_dev_put(mdev);
141 // Error indicates full buffer, this
142 // callback will get retried.
143 if (rc < 0)
144 goto out;
145 }
146 }
147 idx++;
148 // reset for next iteration
149 mcb->a_idx = 0;
150 }
151 }
152 out:
153 rcu_read_unlock();
154 mcb->idx = idx;
155
156 return skb->len;
157 }
158
mctp_addr_notify(struct mctp_dev * mdev,mctp_eid_t eid,int msg_type,struct sk_buff * req_skb,struct nlmsghdr * req_nlh)159 static void mctp_addr_notify(struct mctp_dev *mdev, mctp_eid_t eid, int msg_type,
160 struct sk_buff *req_skb, struct nlmsghdr *req_nlh)
161 {
162 u32 portid = NETLINK_CB(req_skb).portid;
163 struct net *net = dev_net(mdev->dev);
164 struct sk_buff *skb;
165 int rc = -ENOBUFS;
166
167 skb = nlmsg_new(mctp_addrinfo_size(), GFP_KERNEL);
168 if (!skb)
169 goto out;
170
171 rc = mctp_fill_addrinfo(skb, mdev, eid, msg_type,
172 portid, req_nlh->nlmsg_seq, 0);
173 if (rc < 0) {
174 WARN_ON_ONCE(rc == -EMSGSIZE);
175 goto out;
176 }
177
178 rtnl_notify(skb, net, portid, RTNLGRP_MCTP_IFADDR, req_nlh, GFP_KERNEL);
179 return;
180 out:
181 kfree_skb(skb);
182 rtnl_set_sk_err(net, RTNLGRP_MCTP_IFADDR, rc);
183 }
184
185 static const struct nla_policy ifa_mctp_policy[IFA_MAX + 1] = {
186 [IFA_ADDRESS] = { .type = NLA_U8 },
187 [IFA_LOCAL] = { .type = NLA_U8 },
188 };
189
mctp_rtm_newaddr(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)190 static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
191 struct netlink_ext_ack *extack)
192 {
193 struct net *net = sock_net(skb->sk);
194 struct nlattr *tb[IFA_MAX + 1];
195 struct net_device *dev;
196 struct mctp_addr *addr;
197 struct mctp_dev *mdev;
198 struct ifaddrmsg *ifm;
199 unsigned long flags;
200 u8 *tmp_addrs;
201 int rc;
202
203 rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
204 extack);
205 if (rc < 0)
206 return rc;
207
208 ifm = nlmsg_data(nlh);
209
210 if (tb[IFA_LOCAL])
211 addr = nla_data(tb[IFA_LOCAL]);
212 else if (tb[IFA_ADDRESS])
213 addr = nla_data(tb[IFA_ADDRESS]);
214 else
215 return -EINVAL;
216
217 /* find device */
218 dev = __dev_get_by_index(net, ifm->ifa_index);
219 if (!dev)
220 return -ENODEV;
221
222 mdev = mctp_dev_get_rtnl(dev);
223 if (!mdev)
224 return -ENODEV;
225
226 if (!mctp_address_unicast(addr->s_addr))
227 return -EINVAL;
228
229 /* Prevent duplicates. Under RTNL so don't need to lock for reading */
230 if (memchr(mdev->addrs, addr->s_addr, mdev->num_addrs))
231 return -EEXIST;
232
233 tmp_addrs = kmalloc(mdev->num_addrs + 1, GFP_KERNEL);
234 if (!tmp_addrs)
235 return -ENOMEM;
236 memcpy(tmp_addrs, mdev->addrs, mdev->num_addrs);
237 tmp_addrs[mdev->num_addrs] = addr->s_addr;
238
239 /* Lock to write */
240 spin_lock_irqsave(&mdev->addrs_lock, flags);
241 mdev->num_addrs++;
242 swap(mdev->addrs, tmp_addrs);
243 spin_unlock_irqrestore(&mdev->addrs_lock, flags);
244
245 kfree(tmp_addrs);
246
247 mctp_addr_notify(mdev, addr->s_addr, RTM_NEWADDR, skb, nlh);
248 mctp_route_add_local(mdev, addr->s_addr);
249
250 return 0;
251 }
252
mctp_rtm_deladdr(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)253 static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
254 struct netlink_ext_ack *extack)
255 {
256 struct net *net = sock_net(skb->sk);
257 struct nlattr *tb[IFA_MAX + 1];
258 struct net_device *dev;
259 struct mctp_addr *addr;
260 struct mctp_dev *mdev;
261 struct ifaddrmsg *ifm;
262 unsigned long flags;
263 u8 *pos;
264 int rc;
265
266 rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
267 extack);
268 if (rc < 0)
269 return rc;
270
271 ifm = nlmsg_data(nlh);
272
273 if (tb[IFA_LOCAL])
274 addr = nla_data(tb[IFA_LOCAL]);
275 else if (tb[IFA_ADDRESS])
276 addr = nla_data(tb[IFA_ADDRESS]);
277 else
278 return -EINVAL;
279
280 /* find device */
281 dev = __dev_get_by_index(net, ifm->ifa_index);
282 if (!dev)
283 return -ENODEV;
284
285 mdev = mctp_dev_get_rtnl(dev);
286 if (!mdev)
287 return -ENODEV;
288
289 pos = memchr(mdev->addrs, addr->s_addr, mdev->num_addrs);
290 if (!pos)
291 return -ENOENT;
292
293 rc = mctp_route_remove_local(mdev, addr->s_addr);
294 // we can ignore -ENOENT in the case a route was already removed
295 if (rc < 0 && rc != -ENOENT)
296 return rc;
297
298 spin_lock_irqsave(&mdev->addrs_lock, flags);
299 memmove(pos, pos + 1, mdev->num_addrs - 1 - (pos - mdev->addrs));
300 mdev->num_addrs--;
301 spin_unlock_irqrestore(&mdev->addrs_lock, flags);
302
303 mctp_addr_notify(mdev, addr->s_addr, RTM_DELADDR, skb, nlh);
304
305 return 0;
306 }
307
mctp_dev_hold(struct mctp_dev * mdev)308 void mctp_dev_hold(struct mctp_dev *mdev)
309 {
310 refcount_inc(&mdev->refs);
311 }
312
mctp_dev_put(struct mctp_dev * mdev)313 void mctp_dev_put(struct mctp_dev *mdev)
314 {
315 if (mdev && refcount_dec_and_test(&mdev->refs)) {
316 kfree(mdev->addrs);
317 dev_put(mdev->dev);
318 kfree_rcu(mdev, rcu);
319 }
320 }
321
mctp_dev_release_key(struct mctp_dev * dev,struct mctp_sk_key * key)322 void mctp_dev_release_key(struct mctp_dev *dev, struct mctp_sk_key *key)
323 __must_hold(&key->lock)
324 {
325 if (!dev)
326 return;
327 if (dev->ops && dev->ops->release_flow)
328 dev->ops->release_flow(dev, key);
329 key->dev = NULL;
330 mctp_dev_put(dev);
331 }
332
mctp_dev_set_key(struct mctp_dev * dev,struct mctp_sk_key * key)333 void mctp_dev_set_key(struct mctp_dev *dev, struct mctp_sk_key *key)
334 __must_hold(&key->lock)
335 {
336 mctp_dev_hold(dev);
337 key->dev = dev;
338 }
339
mctp_add_dev(struct net_device * dev)340 static struct mctp_dev *mctp_add_dev(struct net_device *dev)
341 {
342 struct mctp_dev *mdev;
343
344 ASSERT_RTNL();
345
346 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
347 if (!mdev)
348 return ERR_PTR(-ENOMEM);
349
350 spin_lock_init(&mdev->addrs_lock);
351
352 mdev->net = mctp_default_net(dev_net(dev));
353
354 /* associate to net_device */
355 refcount_set(&mdev->refs, 1);
356 rcu_assign_pointer(dev->mctp_ptr, mdev);
357
358 dev_hold(dev);
359 mdev->dev = dev;
360
361 return mdev;
362 }
363
mctp_fill_link_af(struct sk_buff * skb,const struct net_device * dev,u32 ext_filter_mask)364 static int mctp_fill_link_af(struct sk_buff *skb,
365 const struct net_device *dev, u32 ext_filter_mask)
366 {
367 struct mctp_dev *mdev;
368
369 mdev = mctp_dev_get_rtnl(dev);
370 if (!mdev)
371 return -ENODATA;
372 if (nla_put_u32(skb, IFLA_MCTP_NET, mdev->net))
373 return -EMSGSIZE;
374 if (nla_put_u8(skb, IFLA_MCTP_PHYS_BINDING, mdev->binding))
375 return -EMSGSIZE;
376 return 0;
377 }
378
mctp_get_link_af_size(const struct net_device * dev,u32 ext_filter_mask)379 static size_t mctp_get_link_af_size(const struct net_device *dev,
380 u32 ext_filter_mask)
381 {
382 struct mctp_dev *mdev;
383 unsigned int ret;
384
385 /* caller holds RCU */
386 mdev = __mctp_dev_get(dev);
387 if (!mdev)
388 return 0;
389 ret = nla_total_size(4); /* IFLA_MCTP_NET */
390 ret += nla_total_size(1); /* IFLA_MCTP_PHYS_BINDING */
391 mctp_dev_put(mdev);
392 return ret;
393 }
394
395 static const struct nla_policy ifla_af_mctp_policy[IFLA_MCTP_MAX + 1] = {
396 [IFLA_MCTP_NET] = { .type = NLA_U32 },
397 };
398
mctp_set_link_af(struct net_device * dev,const struct nlattr * attr,struct netlink_ext_ack * extack)399 static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr,
400 struct netlink_ext_ack *extack)
401 {
402 struct nlattr *tb[IFLA_MCTP_MAX + 1];
403 struct mctp_dev *mdev;
404 int rc;
405
406 rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
407 NULL);
408 if (rc)
409 return rc;
410
411 mdev = mctp_dev_get_rtnl(dev);
412 if (!mdev)
413 return 0;
414
415 if (tb[IFLA_MCTP_NET])
416 WRITE_ONCE(mdev->net, nla_get_u32(tb[IFLA_MCTP_NET]));
417
418 return 0;
419 }
420
421 /* Matches netdev types that should have MCTP handling */
mctp_known(struct net_device * dev)422 static bool mctp_known(struct net_device *dev)
423 {
424 /* only register specific types (inc. NONE for TUN devices) */
425 return dev->type == ARPHRD_MCTP ||
426 dev->type == ARPHRD_LOOPBACK ||
427 dev->type == ARPHRD_NONE;
428 }
429
mctp_unregister(struct net_device * dev)430 static void mctp_unregister(struct net_device *dev)
431 {
432 struct mctp_dev *mdev;
433
434 mdev = mctp_dev_get_rtnl(dev);
435 if (!mdev)
436 return;
437
438 RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL);
439
440 mctp_route_remove_dev(mdev);
441 mctp_neigh_remove_dev(mdev);
442
443 mctp_dev_put(mdev);
444 }
445
mctp_register(struct net_device * dev)446 static int mctp_register(struct net_device *dev)
447 {
448 struct mctp_dev *mdev;
449
450 /* Already registered? */
451 if (rtnl_dereference(dev->mctp_ptr))
452 return 0;
453
454 /* only register specific types */
455 if (!mctp_known(dev))
456 return 0;
457
458 mdev = mctp_add_dev(dev);
459 if (IS_ERR(mdev))
460 return PTR_ERR(mdev);
461
462 return 0;
463 }
464
mctp_dev_notify(struct notifier_block * this,unsigned long event,void * ptr)465 static int mctp_dev_notify(struct notifier_block *this, unsigned long event,
466 void *ptr)
467 {
468 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
469 int rc;
470
471 switch (event) {
472 case NETDEV_REGISTER:
473 rc = mctp_register(dev);
474 if (rc)
475 return notifier_from_errno(rc);
476 break;
477 case NETDEV_UNREGISTER:
478 mctp_unregister(dev);
479 break;
480 }
481
482 return NOTIFY_OK;
483 }
484
mctp_register_netdevice(struct net_device * dev,const struct mctp_netdev_ops * ops,enum mctp_phys_binding binding)485 static int mctp_register_netdevice(struct net_device *dev,
486 const struct mctp_netdev_ops *ops,
487 enum mctp_phys_binding binding)
488 {
489 struct mctp_dev *mdev;
490
491 mdev = mctp_add_dev(dev);
492 if (IS_ERR(mdev))
493 return PTR_ERR(mdev);
494
495 mdev->ops = ops;
496 mdev->binding = binding;
497
498 return register_netdevice(dev);
499 }
500
mctp_register_netdev(struct net_device * dev,const struct mctp_netdev_ops * ops,enum mctp_phys_binding binding)501 int mctp_register_netdev(struct net_device *dev,
502 const struct mctp_netdev_ops *ops,
503 enum mctp_phys_binding binding)
504 {
505 int rc;
506
507 rtnl_lock();
508 rc = mctp_register_netdevice(dev, ops, binding);
509 rtnl_unlock();
510
511 return rc;
512 }
513 EXPORT_SYMBOL_GPL(mctp_register_netdev);
514
mctp_unregister_netdev(struct net_device * dev)515 void mctp_unregister_netdev(struct net_device *dev)
516 {
517 unregister_netdev(dev);
518 }
519 EXPORT_SYMBOL_GPL(mctp_unregister_netdev);
520
521 static struct rtnl_af_ops mctp_af_ops = {
522 .family = AF_MCTP,
523 .fill_link_af = mctp_fill_link_af,
524 .get_link_af_size = mctp_get_link_af_size,
525 .set_link_af = mctp_set_link_af,
526 };
527
528 static struct notifier_block mctp_dev_nb = {
529 .notifier_call = mctp_dev_notify,
530 .priority = ADDRCONF_NOTIFY_PRIORITY,
531 };
532
533 static const struct rtnl_msg_handler mctp_device_rtnl_msg_handlers[] = {
534 {THIS_MODULE, PF_MCTP, RTM_NEWADDR, mctp_rtm_newaddr, NULL, 0},
535 {THIS_MODULE, PF_MCTP, RTM_DELADDR, mctp_rtm_deladdr, NULL, 0},
536 {THIS_MODULE, PF_MCTP, RTM_GETADDR, NULL, mctp_dump_addrinfo, 0},
537 };
538
mctp_device_init(void)539 int __init mctp_device_init(void)
540 {
541 int err;
542
543 register_netdevice_notifier(&mctp_dev_nb);
544
545 err = rtnl_af_register(&mctp_af_ops);
546 if (err)
547 goto err_notifier;
548
549 err = rtnl_register_many(mctp_device_rtnl_msg_handlers);
550 if (err)
551 goto err_af;
552
553 return 0;
554 err_af:
555 rtnl_af_unregister(&mctp_af_ops);
556 err_notifier:
557 unregister_netdevice_notifier(&mctp_dev_nb);
558 return err;
559 }
560
mctp_device_exit(void)561 void __exit mctp_device_exit(void)
562 {
563 rtnl_unregister_many(mctp_device_rtnl_msg_handlers);
564 rtnl_af_unregister(&mctp_af_ops);
565 unregister_netdevice_notifier(&mctp_dev_nb);
566 }
567