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 skb_reset_transport_header(skb); 172 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */ 173 skb_push(skb, sizeof(struct phonethdr)); 174 skb_reset_network_header(skb); 175 ph = pn_hdr(skb); 176 ph->pn_rdev = pn_dev(dst); 177 ph->pn_sdev = pn_dev(src); 178 ph->pn_res = res; 179 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph)); 180 ph->pn_robj = pn_obj(dst); 181 ph->pn_sobj = pn_obj(src); 182 183 skb->protocol = htons(ETH_P_PHONET); 184 skb->priority = 0; 185 skb->dev = dev; 186 187 if (pn_addr(src) == pn_addr(dst)) { 188 skb_reset_mac_header(skb); 189 skb->pkt_type = PACKET_LOOPBACK; 190 skb_orphan(skb); 191 if (irq) 192 netif_rx(skb); 193 else 194 netif_rx_ni(skb); 195 err = 0; 196 } else { 197 err = dev_hard_header(skb, dev, ntohs(skb->protocol), 198 NULL, NULL, skb->len); 199 if (err < 0) { 200 err = -EHOSTUNREACH; 201 goto drop; 202 } 203 err = dev_queue_xmit(skb); 204 } 205 206 return err; 207 drop: 208 kfree_skb(skb); 209 return err; 210 } 211 212 static int pn_raw_send(const void *data, int len, struct net_device *dev, 213 u16 dst, u16 src, u8 res) 214 { 215 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC); 216 if (skb == NULL) 217 return -ENOMEM; 218 219 skb_reserve(skb, MAX_PHONET_HEADER); 220 __skb_put(skb, len); 221 skb_copy_to_linear_data(skb, data, len); 222 return pn_send(skb, dev, dst, src, res, 1); 223 } 224 225 /* 226 * Create a Phonet header for the skb and send it out. Returns 227 * non-zero error code if failed. The skb is freed then. 228 */ 229 int pn_skb_send(struct sock *sk, struct sk_buff *skb, 230 const struct sockaddr_pn *target) 231 { 232 struct net_device *dev; 233 struct pn_sock *pn = pn_sk(sk); 234 int err; 235 u16 src; 236 u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR; 237 238 err = -EHOSTUNREACH; 239 if (sk->sk_bound_dev_if) 240 dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if); 241 else 242 dev = phonet_device_get(sock_net(sk)); 243 if (!dev || !(dev->flags & IFF_UP)) 244 goto drop; 245 246 saddr = phonet_address_get(dev, daddr); 247 if (saddr == PN_NO_ADDR) 248 goto drop; 249 250 src = pn->sobject; 251 if (!pn_addr(src)) 252 src = pn_object(saddr, pn_obj(src)); 253 254 err = pn_send(skb, dev, pn_sockaddr_get_object(target), 255 src, pn_sockaddr_get_resource(target), 0); 256 dev_put(dev); 257 return err; 258 259 drop: 260 kfree_skb(skb); 261 if (dev) 262 dev_put(dev); 263 return err; 264 } 265 EXPORT_SYMBOL(pn_skb_send); 266 267 /* Do not send an error message in response to an error message */ 268 static inline int can_respond(struct sk_buff *skb) 269 { 270 const struct phonethdr *ph; 271 const struct phonetmsg *pm; 272 u8 submsg_id; 273 274 if (!pskb_may_pull(skb, 3)) 275 return 0; 276 277 ph = pn_hdr(skb); 278 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5)) 279 return 0; 280 if (ph->pn_res == PN_COMMGR) /* indications */ 281 return 0; 282 283 ph = pn_hdr(skb); /* re-acquires the pointer */ 284 pm = pn_msg(skb); 285 if (pm->pn_msg_id != PN_COMMON_MESSAGE) 286 return 1; 287 submsg_id = (ph->pn_res == PN_PREFIX) 288 ? pm->pn_e_submsg_id : pm->pn_submsg_id; 289 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP && 290 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP) 291 return 1; 292 return 0; 293 } 294 295 static int send_obj_unreachable(struct sk_buff *rskb) 296 { 297 const struct phonethdr *oph = pn_hdr(rskb); 298 const struct phonetmsg *opm = pn_msg(rskb); 299 struct phonetmsg resp; 300 301 memset(&resp, 0, sizeof(resp)); 302 resp.pn_trans_id = opm->pn_trans_id; 303 resp.pn_msg_id = PN_COMMON_MESSAGE; 304 if (oph->pn_res == PN_PREFIX) { 305 resp.pn_e_res_id = opm->pn_e_res_id; 306 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 307 resp.pn_e_orig_msg_id = opm->pn_msg_id; 308 resp.pn_e_status = 0; 309 } else { 310 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP; 311 resp.pn_orig_msg_id = opm->pn_msg_id; 312 resp.pn_status = 0; 313 } 314 return pn_raw_send(&resp, sizeof(resp), rskb->dev, 315 pn_object(oph->pn_sdev, oph->pn_sobj), 316 pn_object(oph->pn_rdev, oph->pn_robj), 317 oph->pn_res); 318 } 319 320 static int send_reset_indications(struct sk_buff *rskb) 321 { 322 struct phonethdr *oph = pn_hdr(rskb); 323 static const u8 data[4] = { 324 0x00 /* trans ID */, 0x10 /* subscribe msg */, 325 0x00 /* subscription count */, 0x00 /* dummy */ 326 }; 327 328 return pn_raw_send(data, sizeof(data), rskb->dev, 329 pn_object(oph->pn_sdev, 0x00), 330 pn_object(oph->pn_rdev, oph->pn_robj), 331 PN_COMMGR); 332 } 333 334 335 /* packet type functions */ 336 337 /* 338 * Stuff received packets to associated sockets. 339 * On error, returns non-zero and releases the skb. 340 */ 341 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, 342 struct packet_type *pkttype, 343 struct net_device *orig_dev) 344 { 345 struct net *net = dev_net(dev); 346 struct phonethdr *ph; 347 struct sockaddr_pn sa; 348 u16 len; 349 350 /* check we have at least a full Phonet header */ 351 if (!pskb_pull(skb, sizeof(struct phonethdr))) 352 goto out; 353 354 /* check that the advertised length is correct */ 355 ph = pn_hdr(skb); 356 len = get_unaligned_be16(&ph->pn_length); 357 if (len < 2) 358 goto out; 359 len -= 2; 360 if ((len > skb->len) || pskb_trim(skb, len)) 361 goto out; 362 skb_reset_transport_header(skb); 363 364 pn_skb_get_dst_sockaddr(skb, &sa); 365 366 /* check if we are the destination */ 367 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) { 368 /* Phonet packet input */ 369 struct sock *sk = pn_find_sock_by_sa(net, &sa); 370 371 if (sk) 372 return sk_receive_skb(sk, skb, 0); 373 374 if (can_respond(skb)) { 375 send_obj_unreachable(skb); 376 send_reset_indications(skb); 377 } 378 } 379 380 out: 381 kfree_skb(skb); 382 return NET_RX_DROP; 383 } 384 385 static struct packet_type phonet_packet_type __read_mostly = { 386 .type = cpu_to_be16(ETH_P_PHONET), 387 .func = phonet_rcv, 388 }; 389 390 int __init_or_module phonet_proto_register(int protocol, 391 struct phonet_protocol *pp) 392 { 393 int err = 0; 394 395 if (protocol >= PHONET_NPROTO) 396 return -EINVAL; 397 398 err = proto_register(pp->prot, 1); 399 if (err) 400 return err; 401 402 spin_lock(&proto_tab_lock); 403 if (proto_tab[protocol]) 404 err = -EBUSY; 405 else 406 proto_tab[protocol] = pp; 407 spin_unlock(&proto_tab_lock); 408 409 return err; 410 } 411 EXPORT_SYMBOL(phonet_proto_register); 412 413 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp) 414 { 415 spin_lock(&proto_tab_lock); 416 BUG_ON(proto_tab[protocol] != pp); 417 proto_tab[protocol] = NULL; 418 spin_unlock(&proto_tab_lock); 419 proto_unregister(pp->prot); 420 } 421 EXPORT_SYMBOL(phonet_proto_unregister); 422 423 /* Module registration */ 424 static int __init phonet_init(void) 425 { 426 int err; 427 428 err = phonet_device_init(); 429 if (err) 430 return err; 431 432 err = sock_register(&phonet_proto_family); 433 if (err) { 434 printk(KERN_ALERT 435 "phonet protocol family initialization failed\n"); 436 goto err_sock; 437 } 438 439 dev_add_pack(&phonet_packet_type); 440 phonet_sysctl_init(); 441 442 err = isi_register(); 443 if (err) 444 goto err; 445 return 0; 446 447 err: 448 phonet_sysctl_exit(); 449 sock_unregister(PF_PHONET); 450 dev_remove_pack(&phonet_packet_type); 451 err_sock: 452 phonet_device_exit(); 453 return err; 454 } 455 456 static void __exit phonet_exit(void) 457 { 458 isi_unregister(); 459 phonet_sysctl_exit(); 460 sock_unregister(PF_PHONET); 461 dev_remove_pack(&phonet_packet_type); 462 phonet_device_exit(); 463 } 464 465 module_init(phonet_init); 466 module_exit(phonet_exit); 467 MODULE_DESCRIPTION("Phonet protocol stack for Linux"); 468 MODULE_LICENSE("GPL"); 469 MODULE_ALIAS_NETPROTO(PF_PHONET); 470