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