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 static struct net_proto_family phonet_proto_family; 37 static struct phonet_protocol *phonet_proto_get(int protocol); 38 static inline void phonet_proto_put(struct phonet_protocol *pp); 39 40 /* protocol family functions */ 41 42 static int pn_socket_create(struct net *net, struct socket *sock, int protocol) 43 { 44 struct sock *sk; 45 struct pn_sock *pn; 46 struct phonet_protocol *pnp; 47 int err; 48 49 if (net != &init_net) 50 return -EAFNOSUPPORT; 51 52 if (!capable(CAP_SYS_ADMIN)) 53 return -EPERM; 54 55 if (protocol == 0) { 56 /* Default protocol selection */ 57 switch (sock->type) { 58 case SOCK_DGRAM: 59 protocol = PN_PROTO_PHONET; 60 break; 61 case SOCK_SEQPACKET: 62 protocol = PN_PROTO_PIPE; 63 break; 64 default: 65 return -EPROTONOSUPPORT; 66 } 67 } 68 69 pnp = phonet_proto_get(protocol); 70 #ifdef CONFIG_KMOD 71 if (pnp == NULL && 72 request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0) 73 pnp = phonet_proto_get(protocol); 74 #endif 75 if (pnp == NULL) 76 return -EPROTONOSUPPORT; 77 if (sock->type != pnp->sock_type) { 78 err = -EPROTONOSUPPORT; 79 goto out; 80 } 81 82 sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot); 83 if (sk == NULL) { 84 err = -ENOMEM; 85 goto out; 86 } 87 88 sock_init_data(sock, sk); 89 sock->state = SS_UNCONNECTED; 90 sock->ops = pnp->ops; 91 sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv; 92 sk->sk_protocol = protocol; 93 pn = pn_sk(sk); 94 pn->sobject = 0; 95 pn->resource = 0; 96 sk->sk_prot->init(sk); 97 err = 0; 98 99 out: 100 phonet_proto_put(pnp); 101 return err; 102 } 103 104 static struct net_proto_family phonet_proto_family = { 105 .family = PF_PHONET, 106 .create = pn_socket_create, 107 .owner = THIS_MODULE, 108 }; 109 110 /* Phonet device header operations */ 111 static int pn_header_create(struct sk_buff *skb, struct net_device *dev, 112 unsigned short type, const void *daddr, 113 const void *saddr, unsigned len) 114 { 115 u8 *media = skb_push(skb, 1); 116 117 if (type != ETH_P_PHONET) 118 return -1; 119 120 if (!saddr) 121 saddr = dev->dev_addr; 122 *media = *(const u8 *)saddr; 123 return 1; 124 } 125 126 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr) 127 { 128 const u8 *media = skb_mac_header(skb); 129 *haddr = *media; 130 return 1; 131 } 132 133 struct header_ops phonet_header_ops = { 134 .create = pn_header_create, 135 .parse = pn_header_parse, 136 }; 137 EXPORT_SYMBOL(phonet_header_ops); 138 139 /* 140 * Prepends an ISI header and sends a datagram. 141 */ 142 static int pn_send(struct sk_buff *skb, struct net_device *dev, 143 u16 dst, u16 src, u8 res, u8 irq) 144 { 145 struct phonethdr *ph; 146 int err; 147 148 if (skb->len + 2 > 0xffff) { 149 /* Phonet length field would overflow */ 150 err = -EMSGSIZE; 151 goto drop; 152 } 153 154 skb_reset_transport_header(skb); 155 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */ 156 skb_push(skb, sizeof(struct phonethdr)); 157 skb_reset_network_header(skb); 158 ph = pn_hdr(skb); 159 ph->pn_rdev = pn_dev(dst); 160 ph->pn_sdev = pn_dev(src); 161 ph->pn_res = res; 162 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph)); 163 ph->pn_robj = pn_obj(dst); 164 ph->pn_sobj = pn_obj(src); 165 166 skb->protocol = htons(ETH_P_PHONET); 167 skb->priority = 0; 168 skb->dev = dev; 169 170 if (pn_addr(src) == pn_addr(dst)) { 171 skb_reset_mac_header(skb); 172 skb->pkt_type = PACKET_LOOPBACK; 173 skb_orphan(skb); 174 if (irq) 175 netif_rx(skb); 176 else 177 netif_rx_ni(skb); 178 err = 0; 179 } else { 180 err = dev_hard_header(skb, dev, ntohs(skb->protocol), 181 NULL, NULL, skb->len); 182 if (err < 0) { 183 err = -EHOSTUNREACH; 184 goto drop; 185 } 186 err = dev_queue_xmit(skb); 187 } 188 189 return err; 190 drop: 191 kfree_skb(skb); 192 return err; 193 } 194 195 static int pn_raw_send(const void *data, int len, struct net_device *dev, 196 u16 dst, u16 src, u8 res) 197 { 198 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC); 199 if (skb == NULL) 200 return -ENOMEM; 201 202 skb_reserve(skb, MAX_PHONET_HEADER); 203 __skb_put(skb, len); 204 skb_copy_to_linear_data(skb, data, len); 205 return pn_send(skb, dev, dst, src, res, 1); 206 } 207 208 /* 209 * Create a Phonet header for the skb and send it out. Returns 210 * non-zero error code if failed. The skb is freed then. 211 */ 212 int pn_skb_send(struct sock *sk, struct sk_buff *skb, 213 const struct sockaddr_pn *target) 214 { 215 struct net_device *dev; 216 struct pn_sock *pn = pn_sk(sk); 217 int err; 218 u16 src; 219 u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR; 220 221 err = -EHOSTUNREACH; 222 if (sk->sk_bound_dev_if) 223 dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if); 224 else 225 dev = phonet_device_get(sock_net(sk)); 226 if (!dev || !(dev->flags & IFF_UP)) 227 goto drop; 228 229 saddr = phonet_address_get(dev, daddr); 230 if (saddr == PN_NO_ADDR) 231 goto drop; 232 233 src = pn->sobject; 234 if (!pn_addr(src)) 235 src = pn_object(saddr, pn_obj(src)); 236 237 err = pn_send(skb, dev, pn_sockaddr_get_object(target), 238 src, pn_sockaddr_get_resource(target), 0); 239 dev_put(dev); 240 return err; 241 242 drop: 243 kfree_skb(skb); 244 if (dev) 245 dev_put(dev); 246 return err; 247 } 248 EXPORT_SYMBOL(pn_skb_send); 249 250 /* Do not send an error message in response to an error message */ 251 static inline int can_respond(struct sk_buff *skb) 252 { 253 const struct phonethdr *ph; 254 const struct phonetmsg *pm; 255 u8 submsg_id; 256 257 if (!pskb_may_pull(skb, 3)) 258 return 0; 259 260 ph = pn_hdr(skb); 261 if (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev) 262 return 0; /* we are not the destination */ 263 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5)) 264 return 0; 265 266 ph = pn_hdr(skb); /* re-acquires the pointer */ 267 pm = pn_msg(skb); 268 if (pm->pn_msg_id != PN_COMMON_MESSAGE) 269 return 1; 270 submsg_id = (ph->pn_res == PN_PREFIX) 271 ? pm->pn_e_submsg_id : pm->pn_submsg_id; 272 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP && 273 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP) 274 return 1; 275 return 0; 276 } 277 278 static int send_obj_unreachable(struct sk_buff *rskb) 279 { 280 const struct phonethdr *oph = pn_hdr(rskb); 281 const struct phonetmsg *opm = pn_msg(rskb); 282 struct phonetmsg resp; 283 284 memset(&resp, 0, sizeof(resp)); 285 resp.pn_trans_id = opm->pn_trans_id; 286 resp.pn_msg_id = PN_COMMON_MESSAGE; 287 if (oph->pn_res == PN_PREFIX) { 288 resp.pn_e_res_id = opm->pn_e_res_id; 289 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 290 resp.pn_e_orig_msg_id = opm->pn_msg_id; 291 resp.pn_e_status = 0; 292 } else { 293 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 294 resp.pn_orig_msg_id = opm->pn_msg_id; 295 resp.pn_status = 0; 296 } 297 return pn_raw_send(&resp, sizeof(resp), rskb->dev, 298 pn_object(oph->pn_sdev, oph->pn_sobj), 299 pn_object(oph->pn_rdev, oph->pn_robj), 300 oph->pn_res); 301 } 302 303 static int send_reset_indications(struct sk_buff *rskb) 304 { 305 struct phonethdr *oph = pn_hdr(rskb); 306 static const u8 data[4] = { 307 0x00 /* trans ID */, 0x10 /* subscribe msg */, 308 0x00 /* subscription count */, 0x00 /* dummy */ 309 }; 310 311 return pn_raw_send(data, sizeof(data), rskb->dev, 312 pn_object(oph->pn_sdev, 0x00), 313 pn_object(oph->pn_rdev, oph->pn_robj), 0x10); 314 } 315 316 317 /* packet type functions */ 318 319 /* 320 * Stuff received packets to associated sockets. 321 * On error, returns non-zero and releases the skb. 322 */ 323 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, 324 struct packet_type *pkttype, 325 struct net_device *orig_dev) 326 { 327 struct phonethdr *ph; 328 struct sock *sk; 329 struct sockaddr_pn sa; 330 u16 len; 331 332 if (dev_net(dev) != &init_net) 333 goto out; 334 335 /* check we have at least a full Phonet header */ 336 if (!pskb_pull(skb, sizeof(struct phonethdr))) 337 goto out; 338 339 /* check that the advertised length is correct */ 340 ph = pn_hdr(skb); 341 len = get_unaligned_be16(&ph->pn_length); 342 if (len < 2) 343 goto out; 344 len -= 2; 345 if ((len > skb->len) || pskb_trim(skb, len)) 346 goto out; 347 skb_reset_transport_header(skb); 348 349 pn_skb_get_dst_sockaddr(skb, &sa); 350 if (pn_sockaddr_get_addr(&sa) == 0) 351 goto out; /* currently, we cannot be device 0 */ 352 353 sk = pn_find_sock_by_sa(&sa); 354 if (sk == NULL) { 355 if (can_respond(skb)) { 356 send_obj_unreachable(skb); 357 send_reset_indications(skb); 358 } 359 goto out; 360 } 361 362 /* Push data to the socket (or other sockets connected to it). */ 363 return sk_receive_skb(sk, skb, 0); 364 365 out: 366 kfree_skb(skb); 367 return NET_RX_DROP; 368 } 369 370 static struct packet_type phonet_packet_type = { 371 .type = __constant_htons(ETH_P_PHONET), 372 .dev = NULL, 373 .func = phonet_rcv, 374 }; 375 376 /* Transport protocol registration */ 377 static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly; 378 static DEFINE_SPINLOCK(proto_tab_lock); 379 380 int __init_or_module phonet_proto_register(int protocol, 381 struct phonet_protocol *pp) 382 { 383 int err = 0; 384 385 if (protocol >= PHONET_NPROTO) 386 return -EINVAL; 387 388 err = proto_register(pp->prot, 1); 389 if (err) 390 return err; 391 392 spin_lock(&proto_tab_lock); 393 if (proto_tab[protocol]) 394 err = -EBUSY; 395 else 396 proto_tab[protocol] = pp; 397 spin_unlock(&proto_tab_lock); 398 399 return err; 400 } 401 EXPORT_SYMBOL(phonet_proto_register); 402 403 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp) 404 { 405 spin_lock(&proto_tab_lock); 406 BUG_ON(proto_tab[protocol] != pp); 407 proto_tab[protocol] = NULL; 408 spin_unlock(&proto_tab_lock); 409 proto_unregister(pp->prot); 410 } 411 EXPORT_SYMBOL(phonet_proto_unregister); 412 413 static struct phonet_protocol *phonet_proto_get(int protocol) 414 { 415 struct phonet_protocol *pp; 416 417 if (protocol >= PHONET_NPROTO) 418 return NULL; 419 420 spin_lock(&proto_tab_lock); 421 pp = proto_tab[protocol]; 422 if (pp && !try_module_get(pp->prot->owner)) 423 pp = NULL; 424 spin_unlock(&proto_tab_lock); 425 426 return pp; 427 } 428 429 static inline void phonet_proto_put(struct phonet_protocol *pp) 430 { 431 module_put(pp->prot->owner); 432 } 433 434 /* Module registration */ 435 static int __init phonet_init(void) 436 { 437 int err; 438 439 err = sock_register(&phonet_proto_family); 440 if (err) { 441 printk(KERN_ALERT 442 "phonet protocol family initialization failed\n"); 443 return err; 444 } 445 446 phonet_device_init(); 447 dev_add_pack(&phonet_packet_type); 448 phonet_netlink_register(); 449 phonet_sysctl_init(); 450 451 err = isi_register(); 452 if (err) 453 goto err; 454 return 0; 455 456 err: 457 phonet_sysctl_exit(); 458 sock_unregister(PF_PHONET); 459 dev_remove_pack(&phonet_packet_type); 460 phonet_device_exit(); 461 return err; 462 } 463 464 static void __exit phonet_exit(void) 465 { 466 isi_unregister(); 467 phonet_sysctl_exit(); 468 sock_unregister(PF_PHONET); 469 dev_remove_pack(&phonet_packet_type); 470 phonet_device_exit(); 471 } 472 473 module_init(phonet_init); 474 module_exit(phonet_exit); 475 MODULE_DESCRIPTION("Phonet protocol stack for Linux"); 476 MODULE_LICENSE("GPL"); 477 MODULE_ALIAS_NETPROTO(PF_PHONET); 478