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, u8 irq) 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 = (irq ? netif_rx(skb) : netif_rx_ni(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, 1); 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, 0); 273 dev_put(dev); 274 return err; 275 276 drop: 277 kfree_skb(skb); 278 if (dev) 279 dev_put(dev); 280 return err; 281 } 282 EXPORT_SYMBOL(pn_skb_send); 283 284 /* Do not send an error message in response to an error message */ 285 static inline int can_respond(struct sk_buff *skb) 286 { 287 const struct phonethdr *ph; 288 const struct phonetmsg *pm; 289 u8 submsg_id; 290 291 if (!pskb_may_pull(skb, 3)) 292 return 0; 293 294 ph = pn_hdr(skb); 295 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5)) 296 return 0; 297 if (ph->pn_res == PN_COMMGR) /* indications */ 298 return 0; 299 300 ph = pn_hdr(skb); /* re-acquires the pointer */ 301 pm = pn_msg(skb); 302 if (pm->pn_msg_id != PN_COMMON_MESSAGE) 303 return 1; 304 submsg_id = (ph->pn_res == PN_PREFIX) 305 ? pm->pn_e_submsg_id : pm->pn_submsg_id; 306 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP && 307 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP) 308 return 1; 309 return 0; 310 } 311 312 static int send_obj_unreachable(struct sk_buff *rskb) 313 { 314 const struct phonethdr *oph = pn_hdr(rskb); 315 const struct phonetmsg *opm = pn_msg(rskb); 316 struct phonetmsg resp; 317 318 memset(&resp, 0, sizeof(resp)); 319 resp.pn_trans_id = opm->pn_trans_id; 320 resp.pn_msg_id = PN_COMMON_MESSAGE; 321 if (oph->pn_res == PN_PREFIX) { 322 resp.pn_e_res_id = opm->pn_e_res_id; 323 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 324 resp.pn_e_orig_msg_id = opm->pn_msg_id; 325 resp.pn_e_status = 0; 326 } else { 327 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 328 resp.pn_orig_msg_id = opm->pn_msg_id; 329 resp.pn_status = 0; 330 } 331 return pn_raw_send(&resp, sizeof(resp), rskb->dev, 332 pn_object(oph->pn_sdev, oph->pn_sobj), 333 pn_object(oph->pn_rdev, oph->pn_robj), 334 oph->pn_res); 335 } 336 337 static int send_reset_indications(struct sk_buff *rskb) 338 { 339 struct phonethdr *oph = pn_hdr(rskb); 340 static const u8 data[4] = { 341 0x00 /* trans ID */, 0x10 /* subscribe msg */, 342 0x00 /* subscription count */, 0x00 /* dummy */ 343 }; 344 345 return pn_raw_send(data, sizeof(data), rskb->dev, 346 pn_object(oph->pn_sdev, 0x00), 347 pn_object(oph->pn_rdev, oph->pn_robj), 348 PN_COMMGR); 349 } 350 351 352 /* packet type functions */ 353 354 /* 355 * Stuff received packets to associated sockets. 356 * On error, returns non-zero and releases the skb. 357 */ 358 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, 359 struct packet_type *pkttype, 360 struct net_device *orig_dev) 361 { 362 struct net *net = dev_net(dev); 363 struct phonethdr *ph; 364 struct sockaddr_pn sa; 365 u16 len; 366 367 skb = skb_share_check(skb, GFP_ATOMIC); 368 if (!skb) 369 return NET_RX_DROP; 370 371 /* check we have at least a full Phonet header */ 372 if (!pskb_pull(skb, sizeof(struct phonethdr))) 373 goto out; 374 375 /* check that the advertised length is correct */ 376 ph = pn_hdr(skb); 377 len = get_unaligned_be16(&ph->pn_length); 378 if (len < 2) 379 goto out; 380 len -= 2; 381 if ((len > skb->len) || pskb_trim(skb, len)) 382 goto out; 383 skb_reset_transport_header(skb); 384 385 pn_skb_get_dst_sockaddr(skb, &sa); 386 387 /* check if this is broadcasted */ 388 if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) { 389 pn_deliver_sock_broadcast(net, skb); 390 goto out; 391 } 392 393 /* resource routing */ 394 if (pn_sockaddr_get_object(&sa) == 0) { 395 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource); 396 if (sk) 397 return sk_receive_skb(sk, skb, 0); 398 } 399 400 /* check if we are the destination */ 401 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) { 402 /* Phonet packet input */ 403 struct sock *sk = pn_find_sock_by_sa(net, &sa); 404 405 if (sk) 406 return sk_receive_skb(sk, skb, 0); 407 408 if (can_respond(skb)) { 409 send_obj_unreachable(skb); 410 send_reset_indications(skb); 411 } 412 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) 413 goto out; /* Race between address deletion and loopback */ 414 else { 415 /* Phonet packet routing */ 416 struct net_device *out_dev; 417 418 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa)); 419 if (!out_dev) { 420 net_dbg_ratelimited("No Phonet route to %02X\n", 421 pn_sockaddr_get_addr(&sa)); 422 goto out; 423 } 424 425 __skb_push(skb, sizeof(struct phonethdr)); 426 skb->dev = out_dev; 427 if (out_dev == dev) { 428 net_dbg_ratelimited("Phonet loop to %02X on %s\n", 429 pn_sockaddr_get_addr(&sa), 430 dev->name); 431 goto out_dev; 432 } 433 /* Some drivers (e.g. TUN) do not allocate HW header space */ 434 if (skb_cow_head(skb, out_dev->hard_header_len)) 435 goto out_dev; 436 437 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL, 438 skb->len) < 0) 439 goto out_dev; 440 dev_queue_xmit(skb); 441 dev_put(out_dev); 442 return NET_RX_SUCCESS; 443 out_dev: 444 dev_put(out_dev); 445 } 446 447 out: 448 kfree_skb(skb); 449 return NET_RX_DROP; 450 } 451 452 static struct packet_type phonet_packet_type __read_mostly = { 453 .type = cpu_to_be16(ETH_P_PHONET), 454 .func = phonet_rcv, 455 }; 456 457 static DEFINE_MUTEX(proto_tab_lock); 458 459 int __init_or_module phonet_proto_register(unsigned int protocol, 460 const struct phonet_protocol *pp) 461 { 462 int err = 0; 463 464 if (protocol >= PHONET_NPROTO) 465 return -EINVAL; 466 467 err = proto_register(pp->prot, 1); 468 if (err) 469 return err; 470 471 mutex_lock(&proto_tab_lock); 472 if (proto_tab[protocol]) 473 err = -EBUSY; 474 else 475 rcu_assign_pointer(proto_tab[protocol], pp); 476 mutex_unlock(&proto_tab_lock); 477 478 return err; 479 } 480 EXPORT_SYMBOL(phonet_proto_register); 481 482 void phonet_proto_unregister(unsigned int protocol, 483 const struct phonet_protocol *pp) 484 { 485 mutex_lock(&proto_tab_lock); 486 BUG_ON(proto_tab[protocol] != pp); 487 RCU_INIT_POINTER(proto_tab[protocol], NULL); 488 mutex_unlock(&proto_tab_lock); 489 synchronize_rcu(); 490 proto_unregister(pp->prot); 491 } 492 EXPORT_SYMBOL(phonet_proto_unregister); 493 494 /* Module registration */ 495 static int __init phonet_init(void) 496 { 497 int err; 498 499 err = phonet_device_init(); 500 if (err) 501 return err; 502 503 pn_sock_init(); 504 err = sock_register(&phonet_proto_family); 505 if (err) { 506 printk(KERN_ALERT 507 "phonet protocol family initialization failed\n"); 508 goto err_sock; 509 } 510 511 dev_add_pack(&phonet_packet_type); 512 phonet_sysctl_init(); 513 514 err = isi_register(); 515 if (err) 516 goto err; 517 return 0; 518 519 err: 520 phonet_sysctl_exit(); 521 sock_unregister(PF_PHONET); 522 dev_remove_pack(&phonet_packet_type); 523 err_sock: 524 phonet_device_exit(); 525 return err; 526 } 527 528 static void __exit phonet_exit(void) 529 { 530 isi_unregister(); 531 phonet_sysctl_exit(); 532 sock_unregister(PF_PHONET); 533 dev_remove_pack(&phonet_packet_type); 534 phonet_device_exit(); 535 } 536 537 module_init(phonet_init); 538 module_exit(phonet_exit); 539 MODULE_DESCRIPTION("Phonet protocol stack for Linux"); 540 MODULE_LICENSE("GPL"); 541 MODULE_ALIAS_NETPROTO(PF_PHONET); 542