1 /* 2 * File: af_phonet.c 3 * 4 * Phonet protocols family 5 * 6 * Copyright (C) 2008 Nokia Corporation. 7 * 8 * Authors: Sakari Ailus <sakari.ailus@nokia.com> 9 * Rémi Denis-Courmont 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * version 2 as published by the Free Software Foundation. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 23 * 02110-1301 USA 24 */ 25 26 #include <linux/kernel.h> 27 #include <linux/module.h> 28 #include <linux/slab.h> 29 #include <asm/unaligned.h> 30 #include <net/sock.h> 31 32 #include <linux/if_phonet.h> 33 #include <linux/phonet.h> 34 #include <net/phonet/phonet.h> 35 #include <net/phonet/pn_dev.h> 36 37 /* Transport protocol registration */ 38 static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly; 39 40 static const struct phonet_protocol *phonet_proto_get(unsigned int protocol) 41 { 42 const struct phonet_protocol *pp; 43 44 if (protocol >= PHONET_NPROTO) 45 return NULL; 46 47 rcu_read_lock(); 48 pp = rcu_dereference(proto_tab[protocol]); 49 if (pp && !try_module_get(pp->prot->owner)) 50 pp = NULL; 51 rcu_read_unlock(); 52 53 return pp; 54 } 55 56 static inline void phonet_proto_put(const struct phonet_protocol *pp) 57 { 58 module_put(pp->prot->owner); 59 } 60 61 /* protocol family functions */ 62 63 static int pn_socket_create(struct net *net, struct socket *sock, int protocol, 64 int kern) 65 { 66 struct sock *sk; 67 struct pn_sock *pn; 68 const struct phonet_protocol *pnp; 69 int err; 70 71 if (!capable(CAP_SYS_ADMIN)) 72 return -EPERM; 73 74 if (protocol == 0) { 75 /* Default protocol selection */ 76 switch (sock->type) { 77 case SOCK_DGRAM: 78 protocol = PN_PROTO_PHONET; 79 break; 80 case SOCK_SEQPACKET: 81 protocol = PN_PROTO_PIPE; 82 break; 83 default: 84 return -EPROTONOSUPPORT; 85 } 86 } 87 88 pnp = phonet_proto_get(protocol); 89 if (pnp == NULL && 90 request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0) 91 pnp = phonet_proto_get(protocol); 92 93 if (pnp == NULL) 94 return -EPROTONOSUPPORT; 95 if (sock->type != pnp->sock_type) { 96 err = -EPROTONOSUPPORT; 97 goto out; 98 } 99 100 sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern); 101 if (sk == NULL) { 102 err = -ENOMEM; 103 goto out; 104 } 105 106 sock_init_data(sock, sk); 107 sock->state = SS_UNCONNECTED; 108 sock->ops = pnp->ops; 109 sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv; 110 sk->sk_protocol = protocol; 111 pn = pn_sk(sk); 112 pn->sobject = 0; 113 pn->dobject = 0; 114 pn->resource = 0; 115 sk->sk_prot->init(sk); 116 err = 0; 117 118 out: 119 phonet_proto_put(pnp); 120 return err; 121 } 122 123 static const struct net_proto_family phonet_proto_family = { 124 .family = PF_PHONET, 125 .create = pn_socket_create, 126 .owner = THIS_MODULE, 127 }; 128 129 /* Phonet device header operations */ 130 static int pn_header_create(struct sk_buff *skb, struct net_device *dev, 131 unsigned short type, const void *daddr, 132 const void *saddr, unsigned int len) 133 { 134 u8 *media = skb_push(skb, 1); 135 136 if (type != ETH_P_PHONET) 137 return -1; 138 139 if (!saddr) 140 saddr = dev->dev_addr; 141 *media = *(const u8 *)saddr; 142 return 1; 143 } 144 145 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr) 146 { 147 const u8 *media = skb_mac_header(skb); 148 *haddr = *media; 149 return 1; 150 } 151 152 const struct header_ops phonet_header_ops = { 153 .create = pn_header_create, 154 .parse = pn_header_parse, 155 }; 156 EXPORT_SYMBOL(phonet_header_ops); 157 158 /* 159 * Prepends an ISI header and sends a datagram. 160 */ 161 static int pn_send(struct sk_buff *skb, struct net_device *dev, 162 u16 dst, u16 src, u8 res, u8 irq) 163 { 164 struct phonethdr *ph; 165 int err; 166 167 if (skb->len + 2 > 0xffff /* Phonet length field limit */ || 168 skb->len + sizeof(struct phonethdr) > dev->mtu) { 169 err = -EMSGSIZE; 170 goto drop; 171 } 172 173 /* Broadcast sending is not implemented */ 174 if (pn_addr(dst) == PNADDR_BROADCAST) { 175 err = -EOPNOTSUPP; 176 goto drop; 177 } 178 179 skb_reset_transport_header(skb); 180 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */ 181 skb_push(skb, sizeof(struct phonethdr)); 182 skb_reset_network_header(skb); 183 ph = pn_hdr(skb); 184 ph->pn_rdev = pn_dev(dst); 185 ph->pn_sdev = pn_dev(src); 186 ph->pn_res = res; 187 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph)); 188 ph->pn_robj = pn_obj(dst); 189 ph->pn_sobj = pn_obj(src); 190 191 skb->protocol = htons(ETH_P_PHONET); 192 skb->priority = 0; 193 skb->dev = dev; 194 195 if (skb->pkt_type == PACKET_LOOPBACK) { 196 skb_reset_mac_header(skb); 197 skb_orphan(skb); 198 err = (irq ? netif_rx(skb) : netif_rx_ni(skb)) ? -ENOBUFS : 0; 199 } else { 200 err = dev_hard_header(skb, dev, ntohs(skb->protocol), 201 NULL, NULL, skb->len); 202 if (err < 0) { 203 err = -EHOSTUNREACH; 204 goto drop; 205 } 206 err = dev_queue_xmit(skb); 207 if (unlikely(err > 0)) 208 err = net_xmit_errno(err); 209 } 210 211 return err; 212 drop: 213 kfree_skb(skb); 214 return err; 215 } 216 217 static int pn_raw_send(const void *data, int len, struct net_device *dev, 218 u16 dst, u16 src, u8 res) 219 { 220 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC); 221 if (skb == NULL) 222 return -ENOMEM; 223 224 if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0) 225 skb->pkt_type = PACKET_LOOPBACK; 226 227 skb_reserve(skb, MAX_PHONET_HEADER); 228 __skb_put(skb, len); 229 skb_copy_to_linear_data(skb, data, len); 230 return pn_send(skb, dev, dst, src, res, 1); 231 } 232 233 /* 234 * Create a Phonet header for the skb and send it out. Returns 235 * non-zero error code if failed. The skb is freed then. 236 */ 237 int pn_skb_send(struct sock *sk, struct sk_buff *skb, 238 const struct sockaddr_pn *target) 239 { 240 struct net *net = sock_net(sk); 241 struct net_device *dev; 242 struct pn_sock *pn = pn_sk(sk); 243 int err; 244 u16 src, dst; 245 u8 daddr, saddr, res; 246 247 src = pn->sobject; 248 if (target != NULL) { 249 dst = pn_sockaddr_get_object(target); 250 res = pn_sockaddr_get_resource(target); 251 } else { 252 dst = pn->dobject; 253 res = pn->resource; 254 } 255 daddr = pn_addr(dst); 256 257 err = -EHOSTUNREACH; 258 if (sk->sk_bound_dev_if) 259 dev = dev_get_by_index(net, sk->sk_bound_dev_if); 260 else if (phonet_address_lookup(net, daddr) == 0) { 261 dev = phonet_device_get(net); 262 skb->pkt_type = PACKET_LOOPBACK; 263 } else if (dst == 0) { 264 /* Resource routing (small race until phonet_rcv()) */ 265 struct sock *sk = pn_find_sock_by_res(net, res); 266 if (sk) { 267 sock_put(sk); 268 dev = phonet_device_get(net); 269 skb->pkt_type = PACKET_LOOPBACK; 270 } else 271 dev = phonet_route_output(net, daddr); 272 } else 273 dev = phonet_route_output(net, daddr); 274 275 if (!dev || !(dev->flags & IFF_UP)) 276 goto drop; 277 278 saddr = phonet_address_get(dev, daddr); 279 if (saddr == PN_NO_ADDR) 280 goto drop; 281 282 if (!pn_addr(src)) 283 src = pn_object(saddr, pn_obj(src)); 284 285 err = pn_send(skb, dev, dst, src, res, 0); 286 dev_put(dev); 287 return err; 288 289 drop: 290 kfree_skb(skb); 291 if (dev) 292 dev_put(dev); 293 return err; 294 } 295 EXPORT_SYMBOL(pn_skb_send); 296 297 /* Do not send an error message in response to an error message */ 298 static inline int can_respond(struct sk_buff *skb) 299 { 300 const struct phonethdr *ph; 301 const struct phonetmsg *pm; 302 u8 submsg_id; 303 304 if (!pskb_may_pull(skb, 3)) 305 return 0; 306 307 ph = pn_hdr(skb); 308 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5)) 309 return 0; 310 if (ph->pn_res == PN_COMMGR) /* indications */ 311 return 0; 312 313 ph = pn_hdr(skb); /* re-acquires the pointer */ 314 pm = pn_msg(skb); 315 if (pm->pn_msg_id != PN_COMMON_MESSAGE) 316 return 1; 317 submsg_id = (ph->pn_res == PN_PREFIX) 318 ? pm->pn_e_submsg_id : pm->pn_submsg_id; 319 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP && 320 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP) 321 return 1; 322 return 0; 323 } 324 325 static int send_obj_unreachable(struct sk_buff *rskb) 326 { 327 const struct phonethdr *oph = pn_hdr(rskb); 328 const struct phonetmsg *opm = pn_msg(rskb); 329 struct phonetmsg resp; 330 331 memset(&resp, 0, sizeof(resp)); 332 resp.pn_trans_id = opm->pn_trans_id; 333 resp.pn_msg_id = PN_COMMON_MESSAGE; 334 if (oph->pn_res == PN_PREFIX) { 335 resp.pn_e_res_id = opm->pn_e_res_id; 336 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 337 resp.pn_e_orig_msg_id = opm->pn_msg_id; 338 resp.pn_e_status = 0; 339 } else { 340 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 341 resp.pn_orig_msg_id = opm->pn_msg_id; 342 resp.pn_status = 0; 343 } 344 return pn_raw_send(&resp, sizeof(resp), rskb->dev, 345 pn_object(oph->pn_sdev, oph->pn_sobj), 346 pn_object(oph->pn_rdev, oph->pn_robj), 347 oph->pn_res); 348 } 349 350 static int send_reset_indications(struct sk_buff *rskb) 351 { 352 struct phonethdr *oph = pn_hdr(rskb); 353 static const u8 data[4] = { 354 0x00 /* trans ID */, 0x10 /* subscribe msg */, 355 0x00 /* subscription count */, 0x00 /* dummy */ 356 }; 357 358 return pn_raw_send(data, sizeof(data), rskb->dev, 359 pn_object(oph->pn_sdev, 0x00), 360 pn_object(oph->pn_rdev, oph->pn_robj), 361 PN_COMMGR); 362 } 363 364 365 /* packet type functions */ 366 367 /* 368 * Stuff received packets to associated sockets. 369 * On error, returns non-zero and releases the skb. 370 */ 371 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, 372 struct packet_type *pkttype, 373 struct net_device *orig_dev) 374 { 375 struct net *net = dev_net(dev); 376 struct phonethdr *ph; 377 struct sockaddr_pn sa; 378 u16 len; 379 380 skb = skb_share_check(skb, GFP_ATOMIC); 381 if (!skb) 382 return NET_RX_DROP; 383 384 /* check we have at least a full Phonet header */ 385 if (!pskb_pull(skb, sizeof(struct phonethdr))) 386 goto out; 387 388 /* check that the advertised length is correct */ 389 ph = pn_hdr(skb); 390 len = get_unaligned_be16(&ph->pn_length); 391 if (len < 2) 392 goto out; 393 len -= 2; 394 if ((len > skb->len) || pskb_trim(skb, len)) 395 goto out; 396 skb_reset_transport_header(skb); 397 398 pn_skb_get_dst_sockaddr(skb, &sa); 399 400 /* check if this is broadcasted */ 401 if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) { 402 pn_deliver_sock_broadcast(net, skb); 403 goto out; 404 } 405 406 /* resource routing */ 407 if (pn_sockaddr_get_object(&sa) == 0) { 408 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource); 409 if (sk) 410 return sk_receive_skb(sk, skb, 0); 411 } 412 413 /* check if we are the destination */ 414 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) { 415 /* Phonet packet input */ 416 struct sock *sk = pn_find_sock_by_sa(net, &sa); 417 418 if (sk) 419 return sk_receive_skb(sk, skb, 0); 420 421 if (can_respond(skb)) { 422 send_obj_unreachable(skb); 423 send_reset_indications(skb); 424 } 425 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) 426 goto out; /* Race between address deletion and loopback */ 427 else { 428 /* Phonet packet routing */ 429 struct net_device *out_dev; 430 431 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa)); 432 if (!out_dev) { 433 net_dbg_ratelimited("No Phonet route to %02X\n", 434 pn_sockaddr_get_addr(&sa)); 435 goto out; 436 } 437 438 __skb_push(skb, sizeof(struct phonethdr)); 439 skb->dev = out_dev; 440 if (out_dev == dev) { 441 net_dbg_ratelimited("Phonet loop to %02X on %s\n", 442 pn_sockaddr_get_addr(&sa), 443 dev->name); 444 goto out_dev; 445 } 446 /* Some drivers (e.g. TUN) do not allocate HW header space */ 447 if (skb_cow_head(skb, out_dev->hard_header_len)) 448 goto out_dev; 449 450 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL, 451 skb->len) < 0) 452 goto out_dev; 453 dev_queue_xmit(skb); 454 dev_put(out_dev); 455 return NET_RX_SUCCESS; 456 out_dev: 457 dev_put(out_dev); 458 } 459 460 out: 461 kfree_skb(skb); 462 return NET_RX_DROP; 463 } 464 465 static struct packet_type phonet_packet_type __read_mostly = { 466 .type = cpu_to_be16(ETH_P_PHONET), 467 .func = phonet_rcv, 468 }; 469 470 static DEFINE_MUTEX(proto_tab_lock); 471 472 int __init_or_module phonet_proto_register(unsigned int protocol, 473 const struct phonet_protocol *pp) 474 { 475 int err = 0; 476 477 if (protocol >= PHONET_NPROTO) 478 return -EINVAL; 479 480 err = proto_register(pp->prot, 1); 481 if (err) 482 return err; 483 484 mutex_lock(&proto_tab_lock); 485 if (proto_tab[protocol]) 486 err = -EBUSY; 487 else 488 rcu_assign_pointer(proto_tab[protocol], pp); 489 mutex_unlock(&proto_tab_lock); 490 491 return err; 492 } 493 EXPORT_SYMBOL(phonet_proto_register); 494 495 void phonet_proto_unregister(unsigned int protocol, 496 const struct phonet_protocol *pp) 497 { 498 mutex_lock(&proto_tab_lock); 499 BUG_ON(proto_tab[protocol] != pp); 500 RCU_INIT_POINTER(proto_tab[protocol], NULL); 501 mutex_unlock(&proto_tab_lock); 502 synchronize_rcu(); 503 proto_unregister(pp->prot); 504 } 505 EXPORT_SYMBOL(phonet_proto_unregister); 506 507 /* Module registration */ 508 static int __init phonet_init(void) 509 { 510 int err; 511 512 err = phonet_device_init(); 513 if (err) 514 return err; 515 516 pn_sock_init(); 517 err = sock_register(&phonet_proto_family); 518 if (err) { 519 printk(KERN_ALERT 520 "phonet protocol family initialization failed\n"); 521 goto err_sock; 522 } 523 524 dev_add_pack(&phonet_packet_type); 525 phonet_sysctl_init(); 526 527 err = isi_register(); 528 if (err) 529 goto err; 530 return 0; 531 532 err: 533 phonet_sysctl_exit(); 534 sock_unregister(PF_PHONET); 535 dev_remove_pack(&phonet_packet_type); 536 err_sock: 537 phonet_device_exit(); 538 return err; 539 } 540 541 static void __exit phonet_exit(void) 542 { 543 isi_unregister(); 544 phonet_sysctl_exit(); 545 sock_unregister(PF_PHONET); 546 dev_remove_pack(&phonet_packet_type); 547 phonet_device_exit(); 548 } 549 550 module_init(phonet_init); 551 module_exit(phonet_exit); 552 MODULE_DESCRIPTION("Phonet protocol stack for Linux"); 553 MODULE_LICENSE("GPL"); 554 MODULE_ALIAS_NETPROTO(PF_PHONET); 555