1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * File: af_phonet.c 4 * 5 * Phonet protocols family 6 * 7 * Copyright (C) 2008 Nokia Corporation. 8 * 9 * Authors: Sakari Ailus <sakari.ailus@nokia.com> 10 * Rémi Denis-Courmont 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/slab.h> 16 #include <asm/unaligned.h> 17 #include <net/sock.h> 18 19 #include <linux/if_phonet.h> 20 #include <linux/phonet.h> 21 #include <net/phonet/phonet.h> 22 #include <net/phonet/pn_dev.h> 23 24 /* Transport protocol registration */ 25 static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly; 26 27 static const struct phonet_protocol *phonet_proto_get(unsigned int protocol) 28 { 29 const struct phonet_protocol *pp; 30 31 if (protocol >= PHONET_NPROTO) 32 return NULL; 33 34 rcu_read_lock(); 35 pp = rcu_dereference(proto_tab[protocol]); 36 if (pp && !try_module_get(pp->prot->owner)) 37 pp = NULL; 38 rcu_read_unlock(); 39 40 return pp; 41 } 42 43 static inline void phonet_proto_put(const struct phonet_protocol *pp) 44 { 45 module_put(pp->prot->owner); 46 } 47 48 /* protocol family functions */ 49 50 static int pn_socket_create(struct net *net, struct socket *sock, int protocol, 51 int kern) 52 { 53 struct sock *sk; 54 struct pn_sock *pn; 55 const struct phonet_protocol *pnp; 56 int err; 57 58 if (!capable(CAP_SYS_ADMIN)) 59 return -EPERM; 60 61 if (protocol == 0) { 62 /* Default protocol selection */ 63 switch (sock->type) { 64 case SOCK_DGRAM: 65 protocol = PN_PROTO_PHONET; 66 break; 67 case SOCK_SEQPACKET: 68 protocol = PN_PROTO_PIPE; 69 break; 70 default: 71 return -EPROTONOSUPPORT; 72 } 73 } 74 75 pnp = phonet_proto_get(protocol); 76 if (pnp == NULL && 77 request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0) 78 pnp = phonet_proto_get(protocol); 79 80 if (pnp == NULL) 81 return -EPROTONOSUPPORT; 82 if (sock->type != pnp->sock_type) { 83 err = -EPROTONOSUPPORT; 84 goto out; 85 } 86 87 sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern); 88 if (sk == NULL) { 89 err = -ENOMEM; 90 goto out; 91 } 92 93 sock_init_data(sock, sk); 94 sock->state = SS_UNCONNECTED; 95 sock->ops = pnp->ops; 96 sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv; 97 sk->sk_protocol = protocol; 98 pn = pn_sk(sk); 99 pn->sobject = 0; 100 pn->dobject = 0; 101 pn->resource = 0; 102 sk->sk_prot->init(sk); 103 err = 0; 104 105 out: 106 phonet_proto_put(pnp); 107 return err; 108 } 109 110 static const struct net_proto_family phonet_proto_family = { 111 .family = PF_PHONET, 112 .create = pn_socket_create, 113 .owner = THIS_MODULE, 114 }; 115 116 /* Phonet device header operations */ 117 static int pn_header_create(struct sk_buff *skb, struct net_device *dev, 118 unsigned short type, const void *daddr, 119 const void *saddr, unsigned int len) 120 { 121 u8 *media = skb_push(skb, 1); 122 123 if (type != ETH_P_PHONET) 124 return -1; 125 126 if (!saddr) 127 saddr = dev->dev_addr; 128 *media = *(const u8 *)saddr; 129 return 1; 130 } 131 132 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr) 133 { 134 const u8 *media = skb_mac_header(skb); 135 *haddr = *media; 136 return 1; 137 } 138 139 const struct header_ops phonet_header_ops = { 140 .create = pn_header_create, 141 .parse = pn_header_parse, 142 }; 143 EXPORT_SYMBOL(phonet_header_ops); 144 145 /* 146 * Prepends an ISI header and sends a datagram. 147 */ 148 static int pn_send(struct sk_buff *skb, struct net_device *dev, 149 u16 dst, u16 src, u8 res) 150 { 151 struct phonethdr *ph; 152 int err; 153 154 if (skb->len + 2 > 0xffff /* Phonet length field limit */ || 155 skb->len + sizeof(struct phonethdr) > dev->mtu) { 156 err = -EMSGSIZE; 157 goto drop; 158 } 159 160 /* Broadcast sending is not implemented */ 161 if (pn_addr(dst) == PNADDR_BROADCAST) { 162 err = -EOPNOTSUPP; 163 goto drop; 164 } 165 166 skb_reset_transport_header(skb); 167 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */ 168 skb_push(skb, sizeof(struct phonethdr)); 169 skb_reset_network_header(skb); 170 ph = pn_hdr(skb); 171 ph->pn_rdev = pn_dev(dst); 172 ph->pn_sdev = pn_dev(src); 173 ph->pn_res = res; 174 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph)); 175 ph->pn_robj = pn_obj(dst); 176 ph->pn_sobj = pn_obj(src); 177 178 skb->protocol = htons(ETH_P_PHONET); 179 skb->priority = 0; 180 skb->dev = dev; 181 182 if (skb->pkt_type == PACKET_LOOPBACK) { 183 skb_reset_mac_header(skb); 184 skb_orphan(skb); 185 err = netif_rx(skb) ? -ENOBUFS : 0; 186 } else { 187 err = dev_hard_header(skb, dev, ntohs(skb->protocol), 188 NULL, NULL, skb->len); 189 if (err < 0) { 190 err = -EHOSTUNREACH; 191 goto drop; 192 } 193 err = dev_queue_xmit(skb); 194 if (unlikely(err > 0)) 195 err = net_xmit_errno(err); 196 } 197 198 return err; 199 drop: 200 kfree_skb(skb); 201 return err; 202 } 203 204 static int pn_raw_send(const void *data, int len, struct net_device *dev, 205 u16 dst, u16 src, u8 res) 206 { 207 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC); 208 if (skb == NULL) 209 return -ENOMEM; 210 211 if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0) 212 skb->pkt_type = PACKET_LOOPBACK; 213 214 skb_reserve(skb, MAX_PHONET_HEADER); 215 __skb_put(skb, len); 216 skb_copy_to_linear_data(skb, data, len); 217 return pn_send(skb, dev, dst, src, res); 218 } 219 220 /* 221 * Create a Phonet header for the skb and send it out. Returns 222 * non-zero error code if failed. The skb is freed then. 223 */ 224 int pn_skb_send(struct sock *sk, struct sk_buff *skb, 225 const struct sockaddr_pn *target) 226 { 227 struct net *net = sock_net(sk); 228 struct net_device *dev; 229 struct pn_sock *pn = pn_sk(sk); 230 int err; 231 u16 src, dst; 232 u8 daddr, saddr, res; 233 234 src = pn->sobject; 235 if (target != NULL) { 236 dst = pn_sockaddr_get_object(target); 237 res = pn_sockaddr_get_resource(target); 238 } else { 239 dst = pn->dobject; 240 res = pn->resource; 241 } 242 daddr = pn_addr(dst); 243 244 err = -EHOSTUNREACH; 245 if (sk->sk_bound_dev_if) 246 dev = dev_get_by_index(net, sk->sk_bound_dev_if); 247 else if (phonet_address_lookup(net, daddr) == 0) { 248 dev = phonet_device_get(net); 249 skb->pkt_type = PACKET_LOOPBACK; 250 } else if (dst == 0) { 251 /* Resource routing (small race until phonet_rcv()) */ 252 struct sock *sk = pn_find_sock_by_res(net, res); 253 if (sk) { 254 sock_put(sk); 255 dev = phonet_device_get(net); 256 skb->pkt_type = PACKET_LOOPBACK; 257 } else 258 dev = phonet_route_output(net, daddr); 259 } else 260 dev = phonet_route_output(net, daddr); 261 262 if (!dev || !(dev->flags & IFF_UP)) 263 goto drop; 264 265 saddr = phonet_address_get(dev, daddr); 266 if (saddr == PN_NO_ADDR) 267 goto drop; 268 269 if (!pn_addr(src)) 270 src = pn_object(saddr, pn_obj(src)); 271 272 err = pn_send(skb, dev, dst, src, res); 273 dev_put(dev); 274 return err; 275 276 drop: 277 kfree_skb(skb); 278 dev_put(dev); 279 return err; 280 } 281 EXPORT_SYMBOL(pn_skb_send); 282 283 /* Do not send an error message in response to an error message */ 284 static inline int can_respond(struct sk_buff *skb) 285 { 286 const struct phonethdr *ph; 287 const struct phonetmsg *pm; 288 u8 submsg_id; 289 290 if (!pskb_may_pull(skb, 3)) 291 return 0; 292 293 ph = pn_hdr(skb); 294 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5)) 295 return 0; 296 if (ph->pn_res == PN_COMMGR) /* indications */ 297 return 0; 298 299 ph = pn_hdr(skb); /* re-acquires the pointer */ 300 pm = pn_msg(skb); 301 if (pm->pn_msg_id != PN_COMMON_MESSAGE) 302 return 1; 303 submsg_id = (ph->pn_res == PN_PREFIX) 304 ? pm->pn_e_submsg_id : pm->pn_submsg_id; 305 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP && 306 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP) 307 return 1; 308 return 0; 309 } 310 311 static int send_obj_unreachable(struct sk_buff *rskb) 312 { 313 const struct phonethdr *oph = pn_hdr(rskb); 314 const struct phonetmsg *opm = pn_msg(rskb); 315 struct phonetmsg resp; 316 317 memset(&resp, 0, sizeof(resp)); 318 resp.pn_trans_id = opm->pn_trans_id; 319 resp.pn_msg_id = PN_COMMON_MESSAGE; 320 if (oph->pn_res == PN_PREFIX) { 321 resp.pn_e_res_id = opm->pn_e_res_id; 322 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 323 resp.pn_e_orig_msg_id = opm->pn_msg_id; 324 resp.pn_e_status = 0; 325 } else { 326 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 327 resp.pn_orig_msg_id = opm->pn_msg_id; 328 resp.pn_status = 0; 329 } 330 return pn_raw_send(&resp, sizeof(resp), rskb->dev, 331 pn_object(oph->pn_sdev, oph->pn_sobj), 332 pn_object(oph->pn_rdev, oph->pn_robj), 333 oph->pn_res); 334 } 335 336 static int send_reset_indications(struct sk_buff *rskb) 337 { 338 struct phonethdr *oph = pn_hdr(rskb); 339 static const u8 data[4] = { 340 0x00 /* trans ID */, 0x10 /* subscribe msg */, 341 0x00 /* subscription count */, 0x00 /* dummy */ 342 }; 343 344 return pn_raw_send(data, sizeof(data), rskb->dev, 345 pn_object(oph->pn_sdev, 0x00), 346 pn_object(oph->pn_rdev, oph->pn_robj), 347 PN_COMMGR); 348 } 349 350 351 /* packet type functions */ 352 353 /* 354 * Stuff received packets to associated sockets. 355 * On error, returns non-zero and releases the skb. 356 */ 357 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, 358 struct packet_type *pkttype, 359 struct net_device *orig_dev) 360 { 361 struct net *net = dev_net(dev); 362 struct phonethdr *ph; 363 struct sockaddr_pn sa; 364 u16 len; 365 366 skb = skb_share_check(skb, GFP_ATOMIC); 367 if (!skb) 368 return NET_RX_DROP; 369 370 /* check we have at least a full Phonet header */ 371 if (!pskb_pull(skb, sizeof(struct phonethdr))) 372 goto out; 373 374 /* check that the advertised length is correct */ 375 ph = pn_hdr(skb); 376 len = get_unaligned_be16(&ph->pn_length); 377 if (len < 2) 378 goto out; 379 len -= 2; 380 if ((len > skb->len) || pskb_trim(skb, len)) 381 goto out; 382 skb_reset_transport_header(skb); 383 384 pn_skb_get_dst_sockaddr(skb, &sa); 385 386 /* check if this is broadcasted */ 387 if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) { 388 pn_deliver_sock_broadcast(net, skb); 389 goto out; 390 } 391 392 /* resource routing */ 393 if (pn_sockaddr_get_object(&sa) == 0) { 394 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource); 395 if (sk) 396 return sk_receive_skb(sk, skb, 0); 397 } 398 399 /* check if we are the destination */ 400 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) { 401 /* Phonet packet input */ 402 struct sock *sk = pn_find_sock_by_sa(net, &sa); 403 404 if (sk) 405 return sk_receive_skb(sk, skb, 0); 406 407 if (can_respond(skb)) { 408 send_obj_unreachable(skb); 409 send_reset_indications(skb); 410 } 411 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) 412 goto out; /* Race between address deletion and loopback */ 413 else { 414 /* Phonet packet routing */ 415 struct net_device *out_dev; 416 417 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa)); 418 if (!out_dev) { 419 net_dbg_ratelimited("No Phonet route to %02X\n", 420 pn_sockaddr_get_addr(&sa)); 421 goto out; 422 } 423 424 __skb_push(skb, sizeof(struct phonethdr)); 425 skb->dev = out_dev; 426 if (out_dev == dev) { 427 net_dbg_ratelimited("Phonet loop to %02X on %s\n", 428 pn_sockaddr_get_addr(&sa), 429 dev->name); 430 goto out_dev; 431 } 432 /* Some drivers (e.g. TUN) do not allocate HW header space */ 433 if (skb_cow_head(skb, out_dev->hard_header_len)) 434 goto out_dev; 435 436 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL, 437 skb->len) < 0) 438 goto out_dev; 439 dev_queue_xmit(skb); 440 dev_put(out_dev); 441 return NET_RX_SUCCESS; 442 out_dev: 443 dev_put(out_dev); 444 } 445 446 out: 447 kfree_skb(skb); 448 return NET_RX_DROP; 449 } 450 451 static struct packet_type phonet_packet_type __read_mostly = { 452 .type = cpu_to_be16(ETH_P_PHONET), 453 .func = phonet_rcv, 454 }; 455 456 static DEFINE_MUTEX(proto_tab_lock); 457 458 int __init_or_module phonet_proto_register(unsigned int protocol, 459 const struct phonet_protocol *pp) 460 { 461 int err = 0; 462 463 if (protocol >= PHONET_NPROTO) 464 return -EINVAL; 465 466 err = proto_register(pp->prot, 1); 467 if (err) 468 return err; 469 470 mutex_lock(&proto_tab_lock); 471 if (proto_tab[protocol]) 472 err = -EBUSY; 473 else 474 rcu_assign_pointer(proto_tab[protocol], pp); 475 mutex_unlock(&proto_tab_lock); 476 477 return err; 478 } 479 EXPORT_SYMBOL(phonet_proto_register); 480 481 void phonet_proto_unregister(unsigned int protocol, 482 const struct phonet_protocol *pp) 483 { 484 mutex_lock(&proto_tab_lock); 485 BUG_ON(proto_tab[protocol] != pp); 486 RCU_INIT_POINTER(proto_tab[protocol], NULL); 487 mutex_unlock(&proto_tab_lock); 488 synchronize_rcu(); 489 proto_unregister(pp->prot); 490 } 491 EXPORT_SYMBOL(phonet_proto_unregister); 492 493 /* Module registration */ 494 static int __init phonet_init(void) 495 { 496 int err; 497 498 err = phonet_device_init(); 499 if (err) 500 return err; 501 502 pn_sock_init(); 503 err = sock_register(&phonet_proto_family); 504 if (err) { 505 printk(KERN_ALERT 506 "phonet protocol family initialization failed\n"); 507 goto err_sock; 508 } 509 510 dev_add_pack(&phonet_packet_type); 511 phonet_sysctl_init(); 512 513 err = isi_register(); 514 if (err) 515 goto err; 516 return 0; 517 518 err: 519 phonet_sysctl_exit(); 520 sock_unregister(PF_PHONET); 521 dev_remove_pack(&phonet_packet_type); 522 err_sock: 523 phonet_device_exit(); 524 return err; 525 } 526 527 static void __exit phonet_exit(void) 528 { 529 isi_unregister(); 530 phonet_sysctl_exit(); 531 sock_unregister(PF_PHONET); 532 dev_remove_pack(&phonet_packet_type); 533 phonet_device_exit(); 534 } 535 536 module_init(phonet_init); 537 module_exit(phonet_exit); 538 MODULE_DESCRIPTION("Phonet protocol stack for Linux"); 539 MODULE_LICENSE("GPL"); 540 MODULE_ALIAS_NETPROTO(PF_PHONET); 541