Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 1 | /* |
| 2 | * af_can.c - Protocol family CAN core module |
| 3 | * (used by different CAN protocol modules) |
| 4 | * |
| 5 | * Copyright (c) 2002-2007 Volkswagen Group Electronic Research |
| 6 | * All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. Neither the name of Volkswagen nor the names of its contributors |
| 17 | * may be used to endorse or promote products derived from this software |
| 18 | * without specific prior written permission. |
| 19 | * |
| 20 | * Alternatively, provided that this notice is retained in full, this |
| 21 | * software may be distributed under the terms of the GNU General |
| 22 | * Public License ("GPL") version 2, in which case the provisions of the |
| 23 | * GPL apply INSTEAD OF those given above. |
| 24 | * |
| 25 | * The provided data structures and external interfaces from this code |
| 26 | * are not restricted to be used by modules with a GPL compatible license. |
| 27 | * |
| 28 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 29 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 30 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 31 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 32 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 33 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 34 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 35 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 36 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 37 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 38 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
| 39 | * DAMAGE. |
| 40 | * |
| 41 | * Send feedback to <socketcan-users@lists.berlios.de> |
| 42 | * |
| 43 | */ |
| 44 | |
| 45 | #include <linux/module.h> |
| 46 | #include <linux/init.h> |
| 47 | #include <linux/kmod.h> |
| 48 | #include <linux/slab.h> |
| 49 | #include <linux/list.h> |
| 50 | #include <linux/spinlock.h> |
| 51 | #include <linux/rcupdate.h> |
| 52 | #include <linux/uaccess.h> |
| 53 | #include <linux/net.h> |
| 54 | #include <linux/netdevice.h> |
| 55 | #include <linux/socket.h> |
| 56 | #include <linux/if_ether.h> |
| 57 | #include <linux/if_arp.h> |
| 58 | #include <linux/skbuff.h> |
| 59 | #include <linux/can.h> |
| 60 | #include <linux/can/core.h> |
| 61 | #include <net/net_namespace.h> |
| 62 | #include <net/sock.h> |
| 63 | |
| 64 | #include "af_can.h" |
| 65 | |
| 66 | static __initdata const char banner[] = KERN_INFO |
| 67 | "can: controller area network core (" CAN_VERSION_STRING ")\n"; |
| 68 | |
| 69 | MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); |
| 70 | MODULE_LICENSE("Dual BSD/GPL"); |
| 71 | MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " |
| 72 | "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); |
| 73 | |
| 74 | MODULE_ALIAS_NETPROTO(PF_CAN); |
| 75 | |
| 76 | static int stats_timer __read_mostly = 1; |
| 77 | module_param(stats_timer, int, S_IRUGO); |
| 78 | MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); |
| 79 | |
| 80 | HLIST_HEAD(can_rx_dev_list); |
| 81 | static struct dev_rcv_lists can_rx_alldev_list; |
| 82 | static DEFINE_SPINLOCK(can_rcvlists_lock); |
| 83 | |
| 84 | static struct kmem_cache *rcv_cache __read_mostly; |
| 85 | |
| 86 | /* table of registered CAN protocols */ |
| 87 | static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; |
| 88 | static DEFINE_SPINLOCK(proto_tab_lock); |
| 89 | |
| 90 | struct timer_list can_stattimer; /* timer for statistics update */ |
| 91 | struct s_stats can_stats; /* packet statistics */ |
| 92 | struct s_pstats can_pstats; /* receive list statistics */ |
| 93 | |
| 94 | /* |
| 95 | * af_can socket functions |
| 96 | */ |
| 97 | |
| 98 | static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) |
| 99 | { |
| 100 | struct sock *sk = sock->sk; |
| 101 | |
| 102 | switch (cmd) { |
| 103 | |
| 104 | case SIOCGSTAMP: |
| 105 | return sock_get_timestamp(sk, (struct timeval __user *)arg); |
| 106 | |
| 107 | default: |
| 108 | return -ENOIOCTLCMD; |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | static void can_sock_destruct(struct sock *sk) |
| 113 | { |
| 114 | skb_queue_purge(&sk->sk_receive_queue); |
| 115 | } |
| 116 | |
Eric Paris | 3f378b6 | 2009-11-05 22:18:14 -0800 | [diff] [blame] | 117 | static int can_create(struct net *net, struct socket *sock, int protocol, |
| 118 | int kern) |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 119 | { |
| 120 | struct sock *sk; |
| 121 | struct can_proto *cp; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 122 | int err = 0; |
| 123 | |
| 124 | sock->state = SS_UNCONNECTED; |
| 125 | |
| 126 | if (protocol < 0 || protocol >= CAN_NPROTO) |
| 127 | return -EINVAL; |
| 128 | |
Octavian Purdila | 09ad9bc | 2009-11-25 15:14:13 -0800 | [diff] [blame] | 129 | if (!net_eq(net, &init_net)) |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 130 | return -EAFNOSUPPORT; |
| 131 | |
Johannes Berg | 95a5afc | 2008-10-16 15:24:51 -0700 | [diff] [blame] | 132 | #ifdef CONFIG_MODULES |
| 133 | /* try to load protocol module kernel is modular */ |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 134 | if (!proto_tab[protocol]) { |
Urs Thuermann | 5423dd6 | 2008-02-07 18:04:21 -0800 | [diff] [blame] | 135 | err = request_module("can-proto-%d", protocol); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 136 | |
| 137 | /* |
| 138 | * In case of error we only print a message but don't |
| 139 | * return the error code immediately. Below we will |
| 140 | * return -EPROTONOSUPPORT |
| 141 | */ |
Urs Thuermann | 5423dd6 | 2008-02-07 18:04:21 -0800 | [diff] [blame] | 142 | if (err && printk_ratelimit()) |
| 143 | printk(KERN_ERR "can: request_module " |
| 144 | "(can-proto-%d) failed.\n", protocol); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 145 | } |
Urs Thuermann | 5423dd6 | 2008-02-07 18:04:21 -0800 | [diff] [blame] | 146 | #endif |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 147 | |
| 148 | spin_lock(&proto_tab_lock); |
| 149 | cp = proto_tab[protocol]; |
| 150 | if (cp && !try_module_get(cp->prot->owner)) |
| 151 | cp = NULL; |
| 152 | spin_unlock(&proto_tab_lock); |
| 153 | |
| 154 | /* check for available protocol and correct usage */ |
| 155 | |
| 156 | if (!cp) |
| 157 | return -EPROTONOSUPPORT; |
| 158 | |
| 159 | if (cp->type != sock->type) { |
| 160 | err = -EPROTONOSUPPORT; |
| 161 | goto errout; |
| 162 | } |
| 163 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 164 | sock->ops = cp->ops; |
| 165 | |
| 166 | sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); |
| 167 | if (!sk) { |
| 168 | err = -ENOMEM; |
| 169 | goto errout; |
| 170 | } |
| 171 | |
| 172 | sock_init_data(sock, sk); |
| 173 | sk->sk_destruct = can_sock_destruct; |
| 174 | |
| 175 | if (sk->sk_prot->init) |
| 176 | err = sk->sk_prot->init(sk); |
| 177 | |
| 178 | if (err) { |
| 179 | /* release sk on errors */ |
| 180 | sock_orphan(sk); |
| 181 | sock_put(sk); |
| 182 | } |
| 183 | |
| 184 | errout: |
| 185 | module_put(cp->prot->owner); |
| 186 | return err; |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * af_can tx path |
| 191 | */ |
| 192 | |
| 193 | /** |
| 194 | * can_send - transmit a CAN frame (optional with local loopback) |
| 195 | * @skb: pointer to socket buffer with CAN frame in data section |
| 196 | * @loop: loopback for listeners on local CAN sockets (recommended default!) |
| 197 | * |
Oliver Hartkopp | 481a819 | 2009-09-15 01:31:34 -0700 | [diff] [blame] | 198 | * Due to the loopback this routine must not be called from hardirq context. |
| 199 | * |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 200 | * Return: |
| 201 | * 0 on success |
| 202 | * -ENETDOWN when the selected interface is down |
| 203 | * -ENOBUFS on full driver queue (see net_xmit_errno()) |
| 204 | * -ENOMEM when local loopback failed at calling skb_clone() |
| 205 | * -EPERM when trying to send on a non-CAN interface |
Oliver Hartkopp | 7f2d38e | 2008-07-05 23:38:43 -0700 | [diff] [blame] | 206 | * -EINVAL when the skb->data does not contain a valid CAN frame |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 207 | */ |
| 208 | int can_send(struct sk_buff *skb, int loop) |
| 209 | { |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 210 | struct sk_buff *newskb = NULL; |
Oliver Hartkopp | 7f2d38e | 2008-07-05 23:38:43 -0700 | [diff] [blame] | 211 | struct can_frame *cf = (struct can_frame *)skb->data; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 212 | int err; |
| 213 | |
Oliver Hartkopp | 7f2d38e | 2008-07-05 23:38:43 -0700 | [diff] [blame] | 214 | if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) { |
| 215 | kfree_skb(skb); |
| 216 | return -EINVAL; |
| 217 | } |
| 218 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 219 | if (skb->dev->type != ARPHRD_CAN) { |
| 220 | kfree_skb(skb); |
| 221 | return -EPERM; |
| 222 | } |
| 223 | |
| 224 | if (!(skb->dev->flags & IFF_UP)) { |
| 225 | kfree_skb(skb); |
| 226 | return -ENETDOWN; |
| 227 | } |
| 228 | |
| 229 | skb->protocol = htons(ETH_P_CAN); |
| 230 | skb_reset_network_header(skb); |
| 231 | skb_reset_transport_header(skb); |
| 232 | |
| 233 | if (loop) { |
| 234 | /* local loopback of sent CAN frames */ |
| 235 | |
| 236 | /* indication for the CAN driver: do loopback */ |
| 237 | skb->pkt_type = PACKET_LOOPBACK; |
| 238 | |
| 239 | /* |
| 240 | * The reference to the originating sock may be required |
| 241 | * by the receiving socket to check whether the frame is |
| 242 | * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS |
| 243 | * Therefore we have to ensure that skb->sk remains the |
| 244 | * reference to the originating sock by restoring skb->sk |
| 245 | * after each skb_clone() or skb_orphan() usage. |
| 246 | */ |
| 247 | |
| 248 | if (!(skb->dev->flags & IFF_ECHO)) { |
| 249 | /* |
| 250 | * If the interface is not capable to do loopback |
| 251 | * itself, we do it here. |
| 252 | */ |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 253 | newskb = skb_clone(skb, GFP_ATOMIC); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 254 | if (!newskb) { |
| 255 | kfree_skb(skb); |
| 256 | return -ENOMEM; |
| 257 | } |
| 258 | |
| 259 | newskb->sk = skb->sk; |
| 260 | newskb->ip_summed = CHECKSUM_UNNECESSARY; |
| 261 | newskb->pkt_type = PACKET_BROADCAST; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 262 | } |
| 263 | } else { |
| 264 | /* indication for the CAN driver: no loopback required */ |
| 265 | skb->pkt_type = PACKET_HOST; |
| 266 | } |
| 267 | |
| 268 | /* send to netdevice */ |
| 269 | err = dev_queue_xmit(skb); |
| 270 | if (err > 0) |
| 271 | err = net_xmit_errno(err); |
| 272 | |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 273 | if (err) { |
Wei Yongjun | ce030ed | 2009-02-25 00:35:44 +0000 | [diff] [blame] | 274 | kfree_skb(newskb); |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 275 | return err; |
| 276 | } |
| 277 | |
| 278 | if (newskb) |
Oliver Hartkopp | 481a819 | 2009-09-15 01:31:34 -0700 | [diff] [blame] | 279 | netif_rx_ni(newskb); |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 280 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 281 | /* update statistics */ |
| 282 | can_stats.tx_frames++; |
| 283 | can_stats.tx_frames_delta++; |
| 284 | |
Oliver Hartkopp | c2ab7ac | 2008-05-08 02:49:55 -0700 | [diff] [blame] | 285 | return 0; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 286 | } |
| 287 | EXPORT_SYMBOL(can_send); |
| 288 | |
| 289 | /* |
| 290 | * af_can rx path |
| 291 | */ |
| 292 | |
| 293 | static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) |
| 294 | { |
| 295 | struct dev_rcv_lists *d = NULL; |
| 296 | struct hlist_node *n; |
| 297 | |
| 298 | /* |
| 299 | * find receive list for this device |
| 300 | * |
| 301 | * The hlist_for_each_entry*() macros curse through the list |
| 302 | * using the pointer variable n and set d to the containing |
| 303 | * struct in each list iteration. Therefore, after list |
| 304 | * iteration, d is unmodified when the list is empty, and it |
| 305 | * points to last list element, when the list is non-empty |
| 306 | * but no match in the loop body is found. I.e. d is *not* |
| 307 | * NULL when no match is found. We can, however, use the |
| 308 | * cursor variable n to decide if a match was found. |
| 309 | */ |
| 310 | |
| 311 | hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) { |
| 312 | if (d->dev == dev) |
| 313 | break; |
| 314 | } |
| 315 | |
| 316 | return n ? d : NULL; |
| 317 | } |
| 318 | |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 319 | /** |
| 320 | * find_rcv_list - determine optimal filterlist inside device filter struct |
| 321 | * @can_id: pointer to CAN identifier of a given can_filter |
| 322 | * @mask: pointer to CAN mask of a given can_filter |
| 323 | * @d: pointer to the device filter struct |
| 324 | * |
| 325 | * Description: |
| 326 | * Returns the optimal filterlist to reduce the filter handling in the |
| 327 | * receive path. This function is called by service functions that need |
| 328 | * to register or unregister a can_filter in the filter lists. |
| 329 | * |
| 330 | * A filter matches in general, when |
| 331 | * |
| 332 | * <received_can_id> & mask == can_id & mask |
| 333 | * |
| 334 | * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe |
| 335 | * relevant bits for the filter. |
| 336 | * |
| 337 | * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can |
| 338 | * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames |
| 339 | * there is a special filterlist and a special rx path filter handling. |
| 340 | * |
| 341 | * Return: |
| 342 | * Pointer to optimal filterlist for the given can_id/mask pair. |
| 343 | * Constistency checked mask. |
| 344 | * Reduced can_id to have a preprocessed filter compare value. |
| 345 | */ |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 346 | static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, |
| 347 | struct dev_rcv_lists *d) |
| 348 | { |
| 349 | canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ |
| 350 | |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 351 | /* filter for error frames in extra filterlist */ |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 352 | if (*mask & CAN_ERR_FLAG) { |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 353 | /* clear CAN_ERR_FLAG in filter entry */ |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 354 | *mask &= CAN_ERR_MASK; |
| 355 | return &d->rx[RX_ERR]; |
| 356 | } |
| 357 | |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 358 | /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ |
| 359 | |
| 360 | #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) |
| 361 | |
| 362 | /* ensure valid values in can_mask for 'SFF only' frame filtering */ |
| 363 | if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) |
| 364 | *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 365 | |
| 366 | /* reduce condition testing at receive time */ |
| 367 | *can_id &= *mask; |
| 368 | |
| 369 | /* inverse can_id/can_mask filter */ |
| 370 | if (inv) |
| 371 | return &d->rx[RX_INV]; |
| 372 | |
| 373 | /* mask == 0 => no condition testing at receive time */ |
| 374 | if (!(*mask)) |
| 375 | return &d->rx[RX_ALL]; |
| 376 | |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 377 | /* extra filterlists for the subscription of a single non-RTR can_id */ |
Joe Perches | f64f9e7 | 2009-11-29 16:55:45 -0800 | [diff] [blame^] | 378 | if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && |
| 379 | !(*can_id & CAN_RTR_FLAG)) { |
Oliver Hartkopp | d253eee | 2008-12-03 15:52:35 -0800 | [diff] [blame] | 380 | |
| 381 | if (*can_id & CAN_EFF_FLAG) { |
| 382 | if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { |
| 383 | /* RFC: a future use-case for hash-tables? */ |
| 384 | return &d->rx[RX_EFF]; |
| 385 | } |
| 386 | } else { |
| 387 | if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) |
| 388 | return &d->rx_sff[*can_id]; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 389 | } |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 390 | } |
| 391 | |
| 392 | /* default: filter via can_id/can_mask */ |
| 393 | return &d->rx[RX_FIL]; |
| 394 | } |
| 395 | |
| 396 | /** |
| 397 | * can_rx_register - subscribe CAN frames from a specific interface |
| 398 | * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) |
| 399 | * @can_id: CAN identifier (see description) |
| 400 | * @mask: CAN mask (see description) |
| 401 | * @func: callback function on filter match |
| 402 | * @data: returned parameter for callback function |
| 403 | * @ident: string for calling module indentification |
| 404 | * |
| 405 | * Description: |
| 406 | * Invokes the callback function with the received sk_buff and the given |
| 407 | * parameter 'data' on a matching receive filter. A filter matches, when |
| 408 | * |
| 409 | * <received_can_id> & mask == can_id & mask |
| 410 | * |
| 411 | * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can |
| 412 | * filter for error frames (CAN_ERR_FLAG bit set in mask). |
| 413 | * |
Oliver Hartkopp | 1fa17d4 | 2009-01-06 11:07:54 -0800 | [diff] [blame] | 414 | * The provided pointer to the sk_buff is guaranteed to be valid as long as |
| 415 | * the callback function is running. The callback function must *not* free |
| 416 | * the given sk_buff while processing it's task. When the given sk_buff is |
| 417 | * needed after the end of the callback function it must be cloned inside |
| 418 | * the callback function with skb_clone(). |
| 419 | * |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 420 | * Return: |
| 421 | * 0 on success |
| 422 | * -ENOMEM on missing cache mem to create subscription entry |
| 423 | * -ENODEV unknown device |
| 424 | */ |
| 425 | int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, |
| 426 | void (*func)(struct sk_buff *, void *), void *data, |
| 427 | char *ident) |
| 428 | { |
| 429 | struct receiver *r; |
| 430 | struct hlist_head *rl; |
| 431 | struct dev_rcv_lists *d; |
| 432 | int err = 0; |
| 433 | |
| 434 | /* insert new receiver (dev,canid,mask) -> (func,data) */ |
| 435 | |
| 436 | r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); |
| 437 | if (!r) |
| 438 | return -ENOMEM; |
| 439 | |
| 440 | spin_lock(&can_rcvlists_lock); |
| 441 | |
| 442 | d = find_dev_rcv_lists(dev); |
| 443 | if (d) { |
| 444 | rl = find_rcv_list(&can_id, &mask, d); |
| 445 | |
| 446 | r->can_id = can_id; |
| 447 | r->mask = mask; |
| 448 | r->matches = 0; |
| 449 | r->func = func; |
| 450 | r->data = data; |
| 451 | r->ident = ident; |
| 452 | |
| 453 | hlist_add_head_rcu(&r->list, rl); |
| 454 | d->entries++; |
| 455 | |
| 456 | can_pstats.rcv_entries++; |
| 457 | if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) |
| 458 | can_pstats.rcv_entries_max = can_pstats.rcv_entries; |
| 459 | } else { |
| 460 | kmem_cache_free(rcv_cache, r); |
| 461 | err = -ENODEV; |
| 462 | } |
| 463 | |
| 464 | spin_unlock(&can_rcvlists_lock); |
| 465 | |
| 466 | return err; |
| 467 | } |
| 468 | EXPORT_SYMBOL(can_rx_register); |
| 469 | |
| 470 | /* |
| 471 | * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal |
| 472 | */ |
| 473 | static void can_rx_delete_device(struct rcu_head *rp) |
| 474 | { |
| 475 | struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu); |
| 476 | |
| 477 | kfree(d); |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | * can_rx_delete_receiver - rcu callback for single receiver entry removal |
| 482 | */ |
| 483 | static void can_rx_delete_receiver(struct rcu_head *rp) |
| 484 | { |
| 485 | struct receiver *r = container_of(rp, struct receiver, rcu); |
| 486 | |
| 487 | kmem_cache_free(rcv_cache, r); |
| 488 | } |
| 489 | |
| 490 | /** |
| 491 | * can_rx_unregister - unsubscribe CAN frames from a specific interface |
| 492 | * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) |
| 493 | * @can_id: CAN identifier |
| 494 | * @mask: CAN mask |
| 495 | * @func: callback function on filter match |
| 496 | * @data: returned parameter for callback function |
| 497 | * |
| 498 | * Description: |
| 499 | * Removes subscription entry depending on given (subscription) values. |
| 500 | */ |
| 501 | void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, |
| 502 | void (*func)(struct sk_buff *, void *), void *data) |
| 503 | { |
| 504 | struct receiver *r = NULL; |
| 505 | struct hlist_head *rl; |
| 506 | struct hlist_node *next; |
| 507 | struct dev_rcv_lists *d; |
| 508 | |
| 509 | spin_lock(&can_rcvlists_lock); |
| 510 | |
| 511 | d = find_dev_rcv_lists(dev); |
| 512 | if (!d) { |
| 513 | printk(KERN_ERR "BUG: receive list not found for " |
| 514 | "dev %s, id %03X, mask %03X\n", |
| 515 | DNAME(dev), can_id, mask); |
| 516 | goto out; |
| 517 | } |
| 518 | |
| 519 | rl = find_rcv_list(&can_id, &mask, d); |
| 520 | |
| 521 | /* |
| 522 | * Search the receiver list for the item to delete. This should |
| 523 | * exist, since no receiver may be unregistered that hasn't |
| 524 | * been registered before. |
| 525 | */ |
| 526 | |
| 527 | hlist_for_each_entry_rcu(r, next, rl, list) { |
Joe Perches | f64f9e7 | 2009-11-29 16:55:45 -0800 | [diff] [blame^] | 528 | if (r->can_id == can_id && r->mask == mask && |
| 529 | r->func == func && r->data == data) |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 530 | break; |
| 531 | } |
| 532 | |
| 533 | /* |
| 534 | * Check for bugs in CAN protocol implementations: |
| 535 | * If no matching list item was found, the list cursor variable next |
| 536 | * will be NULL, while r will point to the last item of the list. |
| 537 | */ |
| 538 | |
| 539 | if (!next) { |
| 540 | printk(KERN_ERR "BUG: receive list entry not found for " |
| 541 | "dev %s, id %03X, mask %03X\n", |
| 542 | DNAME(dev), can_id, mask); |
| 543 | r = NULL; |
| 544 | d = NULL; |
| 545 | goto out; |
| 546 | } |
| 547 | |
| 548 | hlist_del_rcu(&r->list); |
| 549 | d->entries--; |
| 550 | |
| 551 | if (can_pstats.rcv_entries > 0) |
| 552 | can_pstats.rcv_entries--; |
| 553 | |
| 554 | /* remove device structure requested by NETDEV_UNREGISTER */ |
| 555 | if (d->remove_on_zero_entries && !d->entries) |
| 556 | hlist_del_rcu(&d->list); |
| 557 | else |
| 558 | d = NULL; |
| 559 | |
| 560 | out: |
| 561 | spin_unlock(&can_rcvlists_lock); |
| 562 | |
| 563 | /* schedule the receiver item for deletion */ |
| 564 | if (r) |
| 565 | call_rcu(&r->rcu, can_rx_delete_receiver); |
| 566 | |
| 567 | /* schedule the device structure for deletion */ |
| 568 | if (d) |
| 569 | call_rcu(&d->rcu, can_rx_delete_device); |
| 570 | } |
| 571 | EXPORT_SYMBOL(can_rx_unregister); |
| 572 | |
| 573 | static inline void deliver(struct sk_buff *skb, struct receiver *r) |
| 574 | { |
Oliver Hartkopp | 1fa17d4 | 2009-01-06 11:07:54 -0800 | [diff] [blame] | 575 | r->func(skb, r->data); |
| 576 | r->matches++; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 577 | } |
| 578 | |
| 579 | static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) |
| 580 | { |
| 581 | struct receiver *r; |
| 582 | struct hlist_node *n; |
| 583 | int matches = 0; |
| 584 | struct can_frame *cf = (struct can_frame *)skb->data; |
| 585 | canid_t can_id = cf->can_id; |
| 586 | |
| 587 | if (d->entries == 0) |
| 588 | return 0; |
| 589 | |
| 590 | if (can_id & CAN_ERR_FLAG) { |
| 591 | /* check for error frame entries only */ |
| 592 | hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { |
| 593 | if (can_id & r->mask) { |
| 594 | deliver(skb, r); |
| 595 | matches++; |
| 596 | } |
| 597 | } |
| 598 | return matches; |
| 599 | } |
| 600 | |
| 601 | /* check for unfiltered entries */ |
| 602 | hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { |
| 603 | deliver(skb, r); |
| 604 | matches++; |
| 605 | } |
| 606 | |
| 607 | /* check for can_id/mask entries */ |
| 608 | hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { |
| 609 | if ((can_id & r->mask) == r->can_id) { |
| 610 | deliver(skb, r); |
| 611 | matches++; |
| 612 | } |
| 613 | } |
| 614 | |
| 615 | /* check for inverted can_id/mask entries */ |
| 616 | hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { |
| 617 | if ((can_id & r->mask) != r->can_id) { |
| 618 | deliver(skb, r); |
| 619 | matches++; |
| 620 | } |
| 621 | } |
| 622 | |
Oliver Hartkopp | f706644 | 2008-12-04 15:01:08 -0800 | [diff] [blame] | 623 | /* check filterlists for single non-RTR can_ids */ |
| 624 | if (can_id & CAN_RTR_FLAG) |
| 625 | return matches; |
| 626 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 627 | if (can_id & CAN_EFF_FLAG) { |
| 628 | hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { |
| 629 | if (r->can_id == can_id) { |
| 630 | deliver(skb, r); |
| 631 | matches++; |
| 632 | } |
| 633 | } |
| 634 | } else { |
| 635 | can_id &= CAN_SFF_MASK; |
| 636 | hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { |
| 637 | deliver(skb, r); |
| 638 | matches++; |
| 639 | } |
| 640 | } |
| 641 | |
| 642 | return matches; |
| 643 | } |
| 644 | |
| 645 | static int can_rcv(struct sk_buff *skb, struct net_device *dev, |
| 646 | struct packet_type *pt, struct net_device *orig_dev) |
| 647 | { |
| 648 | struct dev_rcv_lists *d; |
Oliver Hartkopp | 7f2d38e | 2008-07-05 23:38:43 -0700 | [diff] [blame] | 649 | struct can_frame *cf = (struct can_frame *)skb->data; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 650 | int matches; |
| 651 | |
Oliver Hartkopp | 1758c09 | 2009-08-13 22:54:25 +0000 | [diff] [blame] | 652 | if (!net_eq(dev_net(dev), &init_net)) |
| 653 | goto drop; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 654 | |
Oliver Hartkopp | 1758c09 | 2009-08-13 22:54:25 +0000 | [diff] [blame] | 655 | if (WARN_ONCE(dev->type != ARPHRD_CAN || |
| 656 | skb->len != sizeof(struct can_frame) || |
| 657 | cf->can_dlc > 8, |
| 658 | "PF_CAN: dropped non conform skbuf: " |
| 659 | "dev type %d, len %d, can_dlc %d\n", |
| 660 | dev->type, skb->len, cf->can_dlc)) |
| 661 | goto drop; |
Oliver Hartkopp | 7f2d38e | 2008-07-05 23:38:43 -0700 | [diff] [blame] | 662 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 663 | /* update statistics */ |
| 664 | can_stats.rx_frames++; |
| 665 | can_stats.rx_frames_delta++; |
| 666 | |
| 667 | rcu_read_lock(); |
| 668 | |
| 669 | /* deliver the packet to sockets listening on all devices */ |
| 670 | matches = can_rcv_filter(&can_rx_alldev_list, skb); |
| 671 | |
| 672 | /* find receive list for this device */ |
| 673 | d = find_dev_rcv_lists(dev); |
| 674 | if (d) |
| 675 | matches += can_rcv_filter(d, skb); |
| 676 | |
| 677 | rcu_read_unlock(); |
| 678 | |
Oliver Hartkopp | 62bcaa1 | 2009-04-17 01:38:46 -0700 | [diff] [blame] | 679 | /* consume the skbuff allocated by the netdevice driver */ |
| 680 | consume_skb(skb); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 681 | |
| 682 | if (matches > 0) { |
| 683 | can_stats.matches++; |
| 684 | can_stats.matches_delta++; |
| 685 | } |
| 686 | |
Oliver Hartkopp | 6ca8b99 | 2009-08-29 06:45:09 +0000 | [diff] [blame] | 687 | return NET_RX_SUCCESS; |
Oliver Hartkopp | 1758c09 | 2009-08-13 22:54:25 +0000 | [diff] [blame] | 688 | |
| 689 | drop: |
| 690 | kfree_skb(skb); |
Oliver Hartkopp | 6ca8b99 | 2009-08-29 06:45:09 +0000 | [diff] [blame] | 691 | return NET_RX_DROP; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 692 | } |
| 693 | |
| 694 | /* |
| 695 | * af_can protocol functions |
| 696 | */ |
| 697 | |
| 698 | /** |
| 699 | * can_proto_register - register CAN transport protocol |
| 700 | * @cp: pointer to CAN protocol structure |
| 701 | * |
| 702 | * Return: |
| 703 | * 0 on success |
| 704 | * -EINVAL invalid (out of range) protocol number |
| 705 | * -EBUSY protocol already in use |
| 706 | * -ENOBUF if proto_register() fails |
| 707 | */ |
| 708 | int can_proto_register(struct can_proto *cp) |
| 709 | { |
| 710 | int proto = cp->protocol; |
| 711 | int err = 0; |
| 712 | |
| 713 | if (proto < 0 || proto >= CAN_NPROTO) { |
| 714 | printk(KERN_ERR "can: protocol number %d out of range\n", |
| 715 | proto); |
| 716 | return -EINVAL; |
| 717 | } |
| 718 | |
Urs Thuermann | a2fea5f | 2008-02-07 18:04:45 -0800 | [diff] [blame] | 719 | err = proto_register(cp->prot, 0); |
| 720 | if (err < 0) |
| 721 | return err; |
| 722 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 723 | spin_lock(&proto_tab_lock); |
| 724 | if (proto_tab[proto]) { |
| 725 | printk(KERN_ERR "can: protocol %d already registered\n", |
| 726 | proto); |
| 727 | err = -EBUSY; |
Urs Thuermann | a2fea5f | 2008-02-07 18:04:45 -0800 | [diff] [blame] | 728 | } else { |
| 729 | proto_tab[proto] = cp; |
| 730 | |
| 731 | /* use generic ioctl function if not defined by module */ |
| 732 | if (!cp->ops->ioctl) |
| 733 | cp->ops->ioctl = can_ioctl; |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 734 | } |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 735 | spin_unlock(&proto_tab_lock); |
| 736 | |
Urs Thuermann | a2fea5f | 2008-02-07 18:04:45 -0800 | [diff] [blame] | 737 | if (err < 0) |
| 738 | proto_unregister(cp->prot); |
| 739 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 740 | return err; |
| 741 | } |
| 742 | EXPORT_SYMBOL(can_proto_register); |
| 743 | |
| 744 | /** |
| 745 | * can_proto_unregister - unregister CAN transport protocol |
| 746 | * @cp: pointer to CAN protocol structure |
| 747 | */ |
| 748 | void can_proto_unregister(struct can_proto *cp) |
| 749 | { |
| 750 | int proto = cp->protocol; |
| 751 | |
| 752 | spin_lock(&proto_tab_lock); |
| 753 | if (!proto_tab[proto]) { |
| 754 | printk(KERN_ERR "BUG: can: protocol %d is not registered\n", |
| 755 | proto); |
| 756 | } |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 757 | proto_tab[proto] = NULL; |
| 758 | spin_unlock(&proto_tab_lock); |
Urs Thuermann | a2fea5f | 2008-02-07 18:04:45 -0800 | [diff] [blame] | 759 | |
| 760 | proto_unregister(cp->prot); |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 761 | } |
| 762 | EXPORT_SYMBOL(can_proto_unregister); |
| 763 | |
| 764 | /* |
| 765 | * af_can notifier to create/remove CAN netdevice specific structs |
| 766 | */ |
| 767 | static int can_notifier(struct notifier_block *nb, unsigned long msg, |
| 768 | void *data) |
| 769 | { |
| 770 | struct net_device *dev = (struct net_device *)data; |
| 771 | struct dev_rcv_lists *d; |
| 772 | |
YOSHIFUJI Hideaki | 721499e | 2008-07-19 22:34:43 -0700 | [diff] [blame] | 773 | if (!net_eq(dev_net(dev), &init_net)) |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 774 | return NOTIFY_DONE; |
| 775 | |
| 776 | if (dev->type != ARPHRD_CAN) |
| 777 | return NOTIFY_DONE; |
| 778 | |
| 779 | switch (msg) { |
| 780 | |
| 781 | case NETDEV_REGISTER: |
| 782 | |
| 783 | /* |
| 784 | * create new dev_rcv_lists for this device |
| 785 | * |
| 786 | * N.B. zeroing the struct is the correct initialization |
| 787 | * for the embedded hlist_head structs. |
| 788 | * Another list type, e.g. list_head, would require |
| 789 | * explicit initialization. |
| 790 | */ |
| 791 | |
| 792 | d = kzalloc(sizeof(*d), GFP_KERNEL); |
| 793 | if (!d) { |
| 794 | printk(KERN_ERR |
| 795 | "can: allocation of receive list failed\n"); |
| 796 | return NOTIFY_DONE; |
| 797 | } |
| 798 | d->dev = dev; |
| 799 | |
| 800 | spin_lock(&can_rcvlists_lock); |
| 801 | hlist_add_head_rcu(&d->list, &can_rx_dev_list); |
| 802 | spin_unlock(&can_rcvlists_lock); |
| 803 | |
| 804 | break; |
| 805 | |
| 806 | case NETDEV_UNREGISTER: |
| 807 | spin_lock(&can_rcvlists_lock); |
| 808 | |
| 809 | d = find_dev_rcv_lists(dev); |
| 810 | if (d) { |
| 811 | if (d->entries) { |
| 812 | d->remove_on_zero_entries = 1; |
| 813 | d = NULL; |
| 814 | } else |
| 815 | hlist_del_rcu(&d->list); |
| 816 | } else |
| 817 | printk(KERN_ERR "can: notifier: receive list not " |
| 818 | "found for dev %s\n", dev->name); |
| 819 | |
| 820 | spin_unlock(&can_rcvlists_lock); |
| 821 | |
| 822 | if (d) |
| 823 | call_rcu(&d->rcu, can_rx_delete_device); |
| 824 | |
| 825 | break; |
| 826 | } |
| 827 | |
| 828 | return NOTIFY_DONE; |
| 829 | } |
| 830 | |
| 831 | /* |
| 832 | * af_can module init/exit functions |
| 833 | */ |
| 834 | |
| 835 | static struct packet_type can_packet __read_mostly = { |
Harvey Harrison | 09640e6 | 2009-02-01 00:45:17 -0800 | [diff] [blame] | 836 | .type = cpu_to_be16(ETH_P_CAN), |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 837 | .dev = NULL, |
| 838 | .func = can_rcv, |
| 839 | }; |
| 840 | |
Stephen Hemminger | ec1b4cf | 2009-10-05 05:58:39 +0000 | [diff] [blame] | 841 | static const struct net_proto_family can_family_ops = { |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 842 | .family = PF_CAN, |
| 843 | .create = can_create, |
| 844 | .owner = THIS_MODULE, |
| 845 | }; |
| 846 | |
| 847 | /* notifier block for netdevice event */ |
| 848 | static struct notifier_block can_netdev_notifier __read_mostly = { |
| 849 | .notifier_call = can_notifier, |
| 850 | }; |
| 851 | |
| 852 | static __init int can_init(void) |
| 853 | { |
| 854 | printk(banner); |
| 855 | |
| 856 | rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), |
| 857 | 0, 0, NULL); |
| 858 | if (!rcv_cache) |
| 859 | return -ENOMEM; |
| 860 | |
| 861 | /* |
| 862 | * Insert can_rx_alldev_list for reception on all devices. |
| 863 | * This struct is zero initialized which is correct for the |
| 864 | * embedded hlist heads, the dev pointer, and the entries counter. |
| 865 | */ |
| 866 | |
| 867 | spin_lock(&can_rcvlists_lock); |
| 868 | hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list); |
| 869 | spin_unlock(&can_rcvlists_lock); |
| 870 | |
| 871 | if (stats_timer) { |
| 872 | /* the statistics are updated every second (timer triggered) */ |
| 873 | setup_timer(&can_stattimer, can_stat_update, 0); |
| 874 | mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); |
| 875 | } else |
| 876 | can_stattimer.function = NULL; |
| 877 | |
| 878 | can_init_proc(); |
| 879 | |
| 880 | /* protocol register */ |
| 881 | sock_register(&can_family_ops); |
| 882 | register_netdevice_notifier(&can_netdev_notifier); |
| 883 | dev_add_pack(&can_packet); |
| 884 | |
| 885 | return 0; |
| 886 | } |
| 887 | |
| 888 | static __exit void can_exit(void) |
| 889 | { |
| 890 | struct dev_rcv_lists *d; |
| 891 | struct hlist_node *n, *next; |
| 892 | |
| 893 | if (stats_timer) |
| 894 | del_timer(&can_stattimer); |
| 895 | |
| 896 | can_remove_proc(); |
| 897 | |
| 898 | /* protocol unregister */ |
| 899 | dev_remove_pack(&can_packet); |
| 900 | unregister_netdevice_notifier(&can_netdev_notifier); |
| 901 | sock_unregister(PF_CAN); |
| 902 | |
| 903 | /* remove can_rx_dev_list */ |
| 904 | spin_lock(&can_rcvlists_lock); |
| 905 | hlist_del(&can_rx_alldev_list.list); |
| 906 | hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { |
| 907 | hlist_del(&d->list); |
| 908 | kfree(d); |
| 909 | } |
| 910 | spin_unlock(&can_rcvlists_lock); |
| 911 | |
Jesper Dangaard Brouer | 382bfee | 2009-06-08 03:11:38 +0000 | [diff] [blame] | 912 | rcu_barrier(); /* Wait for completion of call_rcu()'s */ |
| 913 | |
Oliver Hartkopp | 0d66548 | 2007-11-16 15:52:17 -0800 | [diff] [blame] | 914 | kmem_cache_destroy(rcv_cache); |
| 915 | } |
| 916 | |
| 917 | module_init(can_init); |
| 918 | module_exit(can_exit); |