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 */ 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 */ 47 struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev) 48 { 49 return rtnl_dereference(dev->mctp_ptr); 50 } 51 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 */ 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 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 } 113 114 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 } 158 159 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 }; 189 190 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 } 252 253 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 } 307 308 void mctp_dev_hold(struct mctp_dev *mdev) 309 { 310 refcount_inc(&mdev->refs); 311 } 312 313 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 } 321 322 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 } 332 333 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 } 339 340 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 } 363 364 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 return 0; 375 } 376 377 static size_t mctp_get_link_af_size(const struct net_device *dev, 378 u32 ext_filter_mask) 379 { 380 struct mctp_dev *mdev; 381 unsigned int ret; 382 383 /* caller holds RCU */ 384 mdev = __mctp_dev_get(dev); 385 if (!mdev) 386 return 0; 387 ret = nla_total_size(4); /* IFLA_MCTP_NET */ 388 mctp_dev_put(mdev); 389 return ret; 390 } 391 392 static const struct nla_policy ifla_af_mctp_policy[IFLA_MCTP_MAX + 1] = { 393 [IFLA_MCTP_NET] = { .type = NLA_U32 }, 394 }; 395 396 static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr, 397 struct netlink_ext_ack *extack) 398 { 399 struct nlattr *tb[IFLA_MCTP_MAX + 1]; 400 struct mctp_dev *mdev; 401 int rc; 402 403 rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy, 404 NULL); 405 if (rc) 406 return rc; 407 408 mdev = mctp_dev_get_rtnl(dev); 409 if (!mdev) 410 return 0; 411 412 if (tb[IFLA_MCTP_NET]) 413 WRITE_ONCE(mdev->net, nla_get_u32(tb[IFLA_MCTP_NET])); 414 415 return 0; 416 } 417 418 /* Matches netdev types that should have MCTP handling */ 419 static bool mctp_known(struct net_device *dev) 420 { 421 /* only register specific types (inc. NONE for TUN devices) */ 422 return dev->type == ARPHRD_MCTP || 423 dev->type == ARPHRD_LOOPBACK || 424 dev->type == ARPHRD_NONE; 425 } 426 427 static void mctp_unregister(struct net_device *dev) 428 { 429 struct mctp_dev *mdev; 430 431 mdev = mctp_dev_get_rtnl(dev); 432 if (!mdev) 433 return; 434 435 RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL); 436 437 mctp_route_remove_dev(mdev); 438 mctp_neigh_remove_dev(mdev); 439 440 mctp_dev_put(mdev); 441 } 442 443 static int mctp_register(struct net_device *dev) 444 { 445 struct mctp_dev *mdev; 446 447 /* Already registered? */ 448 if (rtnl_dereference(dev->mctp_ptr)) 449 return 0; 450 451 /* only register specific types */ 452 if (!mctp_known(dev)) 453 return 0; 454 455 mdev = mctp_add_dev(dev); 456 if (IS_ERR(mdev)) 457 return PTR_ERR(mdev); 458 459 return 0; 460 } 461 462 static int mctp_dev_notify(struct notifier_block *this, unsigned long event, 463 void *ptr) 464 { 465 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 466 int rc; 467 468 switch (event) { 469 case NETDEV_REGISTER: 470 rc = mctp_register(dev); 471 if (rc) 472 return notifier_from_errno(rc); 473 break; 474 case NETDEV_UNREGISTER: 475 mctp_unregister(dev); 476 break; 477 } 478 479 return NOTIFY_OK; 480 } 481 482 static int mctp_register_netdevice(struct net_device *dev, 483 const struct mctp_netdev_ops *ops) 484 { 485 struct mctp_dev *mdev; 486 487 mdev = mctp_add_dev(dev); 488 if (IS_ERR(mdev)) 489 return PTR_ERR(mdev); 490 491 mdev->ops = ops; 492 493 return register_netdevice(dev); 494 } 495 496 int mctp_register_netdev(struct net_device *dev, 497 const struct mctp_netdev_ops *ops) 498 { 499 int rc; 500 501 rtnl_lock(); 502 rc = mctp_register_netdevice(dev, ops); 503 rtnl_unlock(); 504 505 return rc; 506 } 507 EXPORT_SYMBOL_GPL(mctp_register_netdev); 508 509 void mctp_unregister_netdev(struct net_device *dev) 510 { 511 unregister_netdev(dev); 512 } 513 EXPORT_SYMBOL_GPL(mctp_unregister_netdev); 514 515 static struct rtnl_af_ops mctp_af_ops = { 516 .family = AF_MCTP, 517 .fill_link_af = mctp_fill_link_af, 518 .get_link_af_size = mctp_get_link_af_size, 519 .set_link_af = mctp_set_link_af, 520 }; 521 522 static struct notifier_block mctp_dev_nb = { 523 .notifier_call = mctp_dev_notify, 524 .priority = ADDRCONF_NOTIFY_PRIORITY, 525 }; 526 527 static const struct rtnl_msg_handler mctp_device_rtnl_msg_handlers[] = { 528 {THIS_MODULE, PF_MCTP, RTM_NEWADDR, mctp_rtm_newaddr, NULL, 0}, 529 {THIS_MODULE, PF_MCTP, RTM_DELADDR, mctp_rtm_deladdr, NULL, 0}, 530 {THIS_MODULE, PF_MCTP, RTM_GETADDR, NULL, mctp_dump_addrinfo, 0}, 531 }; 532 533 int __init mctp_device_init(void) 534 { 535 int err; 536 537 register_netdevice_notifier(&mctp_dev_nb); 538 rtnl_af_register(&mctp_af_ops); 539 540 err = rtnl_register_many(mctp_device_rtnl_msg_handlers); 541 if (err) { 542 rtnl_af_unregister(&mctp_af_ops); 543 unregister_netdevice_notifier(&mctp_dev_nb); 544 } 545 546 return err; 547 } 548 549 void __exit mctp_device_exit(void) 550 { 551 rtnl_unregister_many(mctp_device_rtnl_msg_handlers); 552 rtnl_af_unregister(&mctp_af_ops); 553 unregister_netdevice_notifier(&mctp_dev_nb); 554 } 555