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