net/can/gw.c

   1 /*
   2  * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
   3  *
   4  * Copyright (c) 2011 Volkswagen Group Electronic Research
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of Volkswagen nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * Alternatively, provided that this notice is retained in full, this
  20  * software may be distributed under the terms of the GNU General
  21  * Public License ("GPL") version 2, in which case the provisions of the
  22  * GPL apply INSTEAD OF those given above.
  23  *
  24  * The provided data structures and external interfaces from this code
  25  * are not restricted to be used by modules with a GPL compatible license.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  38  * DAMAGE.
  39  *
  40  */
  41
  42 #include <linux/module.h>
  43 #include <linux/init.h>
  44 #include <linux/types.h>
  45 #include <linux/list.h>
  46 #include <linux/spinlock.h>
  47 #include <linux/rcupdate.h>
  48 #include <linux/rculist.h>
  49 #include <linux/net.h>
  50 #include <linux/netdevice.h>
  51 #include <linux/if_arp.h>
  52 #include <linux/skbuff.h>
  53 #include <linux/can.h>
  54 #include <linux/can/core.h>
  55 #include <linux/can/gw.h>
  56 #include <net/rtnetlink.h>
  57 #include <net/net_namespace.h>
  58 #include <net/sock.h>
  59
  60 #define CAN_GW_VERSION "20101209"
  61 static __initdata const char banner[] =
  62         KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n";
  63
  64 MODULE_DESCRIPTION("PF_CAN netlink gateway");
  65 MODULE_LICENSE("Dual BSD/GPL");
  66 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
  67 MODULE_ALIAS("can-gw");
  68
  69 HLIST_HEAD(cgw_list);
  70 static struct notifier_block notifier;
  71
  72 static struct kmem_cache *cgw_cache __read_mostly;
  73
  74 /* structure that contains the (on-the-fly) CAN frame modifications */
  75 struct cf_mod {
  76         struct {
  77                 struct can_frame and;
  78                 struct can_frame or;
  79                 struct can_frame xor;
  80                 struct can_frame set;
  81         } modframe;
  82         struct {
  83                 u8 and;
  84                 u8 or;
  85                 u8 xor;
  86                 u8 set;
  87         } modtype;
  88         void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
  89                                           struct cf_mod *mod);
  90
  91         /* CAN frame checksum calculation after CAN frame modifications */
  92         struct {
  93                 struct cgw_csum_xor xor;
  94                 struct cgw_csum_crc8 crc8;
  95         } csum;
  96         struct {
  97                 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
  98                 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
  99         } csumfunc;
 100 };
 101
 102
 103 /*
 104  * So far we just support CAN -> CAN routing and frame modifications.
 105  *
 106  * The internal can_can_gw structure contains data and attributes for
 107  * a CAN -> CAN gateway job.
 108  */
 109 struct can_can_gw {
 110         struct can_filter filter;
 111         int src_idx;
 112         int dst_idx;
 113 };
 114
 115 /* list entry for CAN gateways jobs */
 116 struct cgw_job {
 117         struct hlist_node list;
 118         struct rcu_head rcu;
 119         u32 handled_frames;
 120         u32 dropped_frames;
 121         struct cf_mod mod;
 122         union {
 123                 /* CAN frame data source */
 124                 struct net_device *dev;
 125         } src;
 126         union {
 127                 /* CAN frame data destination */
 128                 struct net_device *dev;
 129         } dst;
 130         union {
 131                 struct can_can_gw ccgw;
 132                 /* tbc */
 133         };
 134         u8 gwtype;
 135         u16 flags;
 136 };
 137
 138 /* modification functions that are invoked in the hot path in can_can_gw_rcv */
 139
 140 #define MODFUNC(func, op) static void func(struct can_frame *cf, \
 141                                            struct cf_mod *mod) { op ; }
 142
 143 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
 144 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
 145 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
 146 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
 147 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
 148 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
 149 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
 150 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
 151 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
 152 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
 153 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
 154 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
 155
 156 static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
 157 {
 158         /*
 159          * Copy the struct members separately to ensure that no uninitialized
 160          * data are copied in the 3 bytes hole of the struct. This is needed
 161          * to make easy compares of the data in the struct cf_mod.
 162          */
 163
 164         dst->can_id = src->can_id;
 165         dst->can_dlc = src->can_dlc;
 166         *(u64 *)dst->data = *(u64 *)src->data;
 167 }
 168
 169 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
 170 {
 171         /*
 172          * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
 173          * relative to received dlc -1 .. -8 :
 174          * e.g. for received dlc = 8
 175          * -1 => index = 7 (data[7])
 176          * -3 => index = 5 (data[5])
 177          * -8 => index = 0 (data[0])
 178          */
 179
 180         if (fr > -9 && fr < 8 &&
 181             to > -9 && to < 8 &&
 182             re > -9 && re < 8)
 183                 return 0;
 184         else
 185                 return -EINVAL;
 186 }
 187
 188 static inline int calc_idx(int idx, int rx_dlc)
 189 {
 190         if (idx < 0)
 191                 return rx_dlc + idx;
 192         else
 193                 return idx;
 194 }
 195
 196 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
 197 {
 198         int from = calc_idx(xor->from_idx, cf->can_dlc);
 199         int to = calc_idx(xor->to_idx, cf->can_dlc);
 200         int res = calc_idx(xor->result_idx, cf->can_dlc);
 201         u8 val = xor->init_xor_val;
 202         int i;
 203
 204         if (from < 0 || to < 0 || res < 0)
 205                 return;
 206
 207         if (from <= to) {
 208                 for (i = from; i <= to; i++)
 209                         val ^= cf->data[i];
 210         } else {
 211                 for (i = from; i >= to; i--)
 212                         val ^= cf->data[i];
 213         }
 214
 215         cf->data[res] = val;
 216 }
 217
 218 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
 219 {
 220         u8 val = xor->init_xor_val;
 221         int i;
 222
 223         for (i = xor->from_idx; i <= xor->to_idx; i++)
 224                 val ^= cf->data[i];
 225
 226         cf->data[xor->result_idx] = val;
 227 }
 228
 229 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
 230 {
 231         u8 val = xor->init_xor_val;
 232         int i;
 233
 234         for (i = xor->from_idx; i >= xor->to_idx; i--)
 235                 val ^= cf->data[i];
 236
 237         cf->data[xor->result_idx] = val;
 238 }
 239
 240 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
 241 {
 242         int from = calc_idx(crc8->from_idx, cf->can_dlc);
 243         int to = calc_idx(crc8->to_idx, cf->can_dlc);
 244         int res = calc_idx(crc8->result_idx, cf->can_dlc);
 245         u8 crc = crc8->init_crc_val;
 246         int i;
 247
 248         if (from < 0 || to < 0 || res < 0)
 249                 return;
 250
 251         if (from <= to) {
 252                 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
 253                         crc = crc8->crctab[crc^cf->data[i]];
 254         } else {
 255                 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
 256                         crc = crc8->crctab[crc^cf->data[i]];
 257         }
 258
 259         switch (crc8->profile) {
 260
 261         case CGW_CRC8PRF_1U8:
 262                 crc = crc8->crctab[crc^crc8->profile_data[0]];
 263                 break;
 264
 265         case  CGW_CRC8PRF_16U8:
 266                 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
 267                 break;
 268
 269         case CGW_CRC8PRF_SFFID_XOR:
 270                 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
 271                                    (cf->can_id >> 8 & 0xFF)];
 272                 break;
 273
 274         }
 275
 276         cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
 277 }
 278
 279 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
 280 {
 281         u8 crc = crc8->init_crc_val;
 282         int i;
 283
 284         for (i = crc8->from_idx; i <= crc8->to_idx; i++)
 285                 crc = crc8->crctab[crc^cf->data[i]];
 286
 287         switch (crc8->profile) {
 288
 289         case CGW_CRC8PRF_1U8:
 290                 crc = crc8->crctab[crc^crc8->profile_data[0]];
 291                 break;
 292
 293         case  CGW_CRC8PRF_16U8:
 294                 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
 295                 break;
 296
 297         case CGW_CRC8PRF_SFFID_XOR:
 298                 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
 299                                    (cf->can_id >> 8 & 0xFF)];
 300                 break;
 301         }
 302
 303         cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
 304 }
 305
 306 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
 307 {
 308         u8 crc = crc8->init_crc_val;
 309         int i;
 310
 311         for (i = crc8->from_idx; i >= crc8->to_idx; i--)
 312                 crc = crc8->crctab[crc^cf->data[i]];
 313
 314         switch (crc8->profile) {
 315
 316         case CGW_CRC8PRF_1U8:
 317                 crc = crc8->crctab[crc^crc8->profile_data[0]];
 318                 break;
 319
 320         case  CGW_CRC8PRF_16U8:
 321                 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
 322                 break;
 323
 324         case CGW_CRC8PRF_SFFID_XOR:
 325                 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
 326                                    (cf->can_id >> 8 & 0xFF)];
 327                 break;
 328         }
 329
 330         cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
 331 }
 332
 333 /* the receive & process & send function */
 334 static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 335 {
 336         struct cgw_job *gwj = (struct cgw_job *)data;
 337         struct can_frame *cf;
 338         struct sk_buff *nskb;
 339         int modidx = 0;
 340
 341         /* do not handle already routed frames - see comment below */
 342         if (skb_mac_header_was_set(skb))
 343                 return;
 344
 345         if (!(gwj->dst.dev->flags & IFF_UP)) {
 346                 gwj->dropped_frames++;
 347                 return;
 348         }
 349
 350         /*
 351          * clone the given skb, which has not been done in can_rcv()
 352          *
 353          * When there is at least one modification function activated,
 354          * we need to copy the skb as we want to modify skb->data.
 355          */
 356         if (gwj->mod.modfunc[0])
 357                 nskb = skb_copy(skb, GFP_ATOMIC);
 358         else
 359                 nskb = skb_clone(skb, GFP_ATOMIC);
 360
 361         if (!nskb) {
 362                 gwj->dropped_frames++;
 363                 return;
 364         }
 365
 366         /*
 367          * Mark routed frames by setting some mac header length which is
 368          * not relevant for the CAN frames located in the skb->data section.
 369          *
 370          * As dev->header_ops is not set in CAN netdevices no one is ever
 371          * accessing the various header offsets in the CAN skbuffs anyway.
 372          * E.g. using the packet socket to read CAN frames is still working.
 373          */
 374         skb_set_mac_header(nskb, 8);
 375         nskb->dev = gwj->dst.dev;
 376
 377         /* pointer to modifiable CAN frame */
 378         cf = (struct can_frame *)nskb->data;
 379
 380         /* perform preprocessed modification functions if there are any */
 381         while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
 382                 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
 383
 384         /* check for checksum updates when the CAN frame has been modified */
 385         if (modidx) {
 386                 if (gwj->mod.csumfunc.crc8)
 387                         (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
 388
 389                 if (gwj->mod.csumfunc.xor)
 390                         (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
 391         }
 392
 393         /* clear the skb timestamp if not configured the other way */
 394         if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
 395                 nskb->tstamp.tv64 = 0;
 396
 397         /* send to netdevice */
 398         if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
 399                 gwj->dropped_frames++;
 400         else
 401                 gwj->handled_frames++;
 402 }
 403
 404 static inline int cgw_register_filter(struct cgw_job *gwj)
 405 {
 406         return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
 407                                gwj->ccgw.filter.can_mask, can_can_gw_rcv,
 408                                gwj, "gw");
 409 }
 410
 411 static inline void cgw_unregister_filter(struct cgw_job *gwj)
 412 {
 413         can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
 414                           gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
 415 }
 416
 417 static int cgw_notifier(struct notifier_block *nb,
 418                         unsigned long msg, void *data)
 419 {
 420         struct net_device *dev = (struct net_device *)data;
 421
 422         if (!net_eq(dev_net(dev), &init_net))
 423                 return NOTIFY_DONE;
 424         if (dev->type != ARPHRD_CAN)
 425                 return NOTIFY_DONE;
 426
 427         if (msg == NETDEV_UNREGISTER) {
 428
 429                 struct cgw_job *gwj = NULL;
 430                 struct hlist_node *n, *nx;
 431
 432                 ASSERT_RTNL();
 433
 434                 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 435
 436                         if (gwj->src.dev == dev || gwj->dst.dev == dev) {
 437                                 hlist_del(&gwj->list);
 438                                 cgw_unregister_filter(gwj);
 439                                 kfree(gwj);
 440                         }
 441                 }
 442         }
 443
 444         return NOTIFY_DONE;
 445 }
 446
 447 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj)
 448 {
 449         struct cgw_frame_mod mb;
 450         struct rtcanmsg *rtcan;
 451         struct nlmsghdr *nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*rtcan), 0);
 452         if (!nlh)
 453                 return -EMSGSIZE;
 454
 455         rtcan = nlmsg_data(nlh);
 456         rtcan->can_family = AF_CAN;
 457         rtcan->gwtype = gwj->gwtype;
 458         rtcan->flags = gwj->flags;
 459
 460         /* add statistics if available */
 461
 462         if (gwj->handled_frames) {
 463                 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
 464                         goto cancel;
 465                 else
 466                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
 467         }
 468
 469         if (gwj->dropped_frames) {
 470                 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
 471                         goto cancel;
 472                 else
 473                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
 474         }
 475
 476         /* check non default settings of attributes */
 477
 478         if (gwj->mod.modtype.and) {
 479                 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
 480                 mb.modtype = gwj->mod.modtype.and;
 481                 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
 482                         goto cancel;
 483                 else
 484                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
 485         }
 486
 487         if (gwj->mod.modtype.or) {
 488                 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
 489                 mb.modtype = gwj->mod.modtype.or;
 490                 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
 491                         goto cancel;
 492                 else
 493                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
 494         }
 495
 496         if (gwj->mod.modtype.xor) {
 497                 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
 498                 mb.modtype = gwj->mod.modtype.xor;
 499                 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
 500                         goto cancel;
 501                 else
 502                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
 503         }
 504
 505         if (gwj->mod.modtype.set) {
 506                 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
 507                 mb.modtype = gwj->mod.modtype.set;
 508                 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
 509                         goto cancel;
 510                 else
 511                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
 512         }
 513
 514         if (gwj->mod.csumfunc.crc8) {
 515                 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
 516                             &gwj->mod.csum.crc8) < 0)
 517                         goto cancel;
 518                 else
 519                         nlh->nlmsg_len += NLA_HDRLEN + \
 520                                 NLA_ALIGN(CGW_CS_CRC8_LEN);
 521         }
 522
 523         if (gwj->mod.csumfunc.xor) {
 524                 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
 525                             &gwj->mod.csum.xor) < 0)
 526                         goto cancel;
 527                 else
 528                         nlh->nlmsg_len += NLA_HDRLEN + \
 529                                 NLA_ALIGN(CGW_CS_XOR_LEN);
 530         }
 531
 532         if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
 533
 534                 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
 535                         if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
 536                                     &gwj->ccgw.filter) < 0)
 537                                 goto cancel;
 538                         else
 539                                 nlh->nlmsg_len += NLA_HDRLEN +
 540                                         NLA_ALIGN(sizeof(struct can_filter));
 541                 }
 542
 543                 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
 544                         goto cancel;
 545                 else
 546                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
 547
 548                 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
 549                         goto cancel;
 550                 else
 551                         nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
 552         }
 553
 554         return skb->len;
 555
 556 cancel:
 557         nlmsg_cancel(skb, nlh);
 558         return -EMSGSIZE;
 559 }
 560
 561 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
 562 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
 563 {
 564         struct cgw_job *gwj = NULL;
 565         struct hlist_node *n;
 566         int idx = 0;
 567         int s_idx = cb->args[0];
 568
 569         rcu_read_lock();
 570         hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
 571                 if (idx < s_idx)
 572                         goto cont;
 573
 574                 if (cgw_put_job(skb, gwj) < 0)
 575                         break;
 576 cont:
 577                 idx++;
 578         }
 579         rcu_read_unlock();
 580
 581         cb->args[0] = idx;
 582
 583         return skb->len;
 584 }
 585
 586 /* check for common and gwtype specific attributes */
 587 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
 588                           u8 gwtype, void *gwtypeattr)
 589 {
 590         struct nlattr *tb[CGW_MAX+1];
 591         struct cgw_frame_mod mb;
 592         int modidx = 0;
 593         int err = 0;
 594
 595         /* initialize modification & checksum data space */
 596         memset(mod, 0, sizeof(*mod));
 597
 598         err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, NULL);
 599         if (err < 0)
 600                 return err;
 601
 602         /* check for AND/OR/XOR/SET modifications */
 603
 604         if (tb[CGW_MOD_AND] &&
 605             nla_len(tb[CGW_MOD_AND]) == CGW_MODATTR_LEN) {
 606                 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
 607
 608                 canframecpy(&mod->modframe.and, &mb.cf);
 609                 mod->modtype.and = mb.modtype;
 610
 611                 if (mb.modtype & CGW_MOD_ID)
 612                         mod->modfunc[modidx++] = mod_and_id;
 613
 614                 if (mb.modtype & CGW_MOD_DLC)
 615                         mod->modfunc[modidx++] = mod_and_dlc;
 616
 617                 if (mb.modtype & CGW_MOD_DATA)
 618                         mod->modfunc[modidx++] = mod_and_data;
 619         }
 620
 621         if (tb[CGW_MOD_OR] &&
 622             nla_len(tb[CGW_MOD_OR]) == CGW_MODATTR_LEN) {
 623                 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
 624
 625                 canframecpy(&mod->modframe.or, &mb.cf);
 626                 mod->modtype.or = mb.modtype;
 627
 628                 if (mb.modtype & CGW_MOD_ID)
 629                         mod->modfunc[modidx++] = mod_or_id;
 630
 631                 if (mb.modtype & CGW_MOD_DLC)
 632                         mod->modfunc[modidx++] = mod_or_dlc;
 633
 634                 if (mb.modtype & CGW_MOD_DATA)
 635                         mod->modfunc[modidx++] = mod_or_data;
 636         }
 637
 638         if (tb[CGW_MOD_XOR] &&
 639             nla_len(tb[CGW_MOD_XOR]) == CGW_MODATTR_LEN) {
 640                 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
 641
 642                 canframecpy(&mod->modframe.xor, &mb.cf);
 643                 mod->modtype.xor = mb.modtype;
 644
 645                 if (mb.modtype & CGW_MOD_ID)
 646                         mod->modfunc[modidx++] = mod_xor_id;
 647
 648                 if (mb.modtype & CGW_MOD_DLC)
 649                         mod->modfunc[modidx++] = mod_xor_dlc;
 650
 651                 if (mb.modtype & CGW_MOD_DATA)
 652                         mod->modfunc[modidx++] = mod_xor_data;
 653         }
 654
 655         if (tb[CGW_MOD_SET] &&
 656             nla_len(tb[CGW_MOD_SET]) == CGW_MODATTR_LEN) {
 657                 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
 658
 659                 canframecpy(&mod->modframe.set, &mb.cf);
 660                 mod->modtype.set = mb.modtype;
 661
 662                 if (mb.modtype & CGW_MOD_ID)
 663                         mod->modfunc[modidx++] = mod_set_id;
 664
 665                 if (mb.modtype & CGW_MOD_DLC)
 666                         mod->modfunc[modidx++] = mod_set_dlc;
 667
 668                 if (mb.modtype & CGW_MOD_DATA)
 669                         mod->modfunc[modidx++] = mod_set_data;
 670         }
 671
 672         /* check for checksum operations after CAN frame modifications */
 673         if (modidx) {
 674
 675                 if (tb[CGW_CS_CRC8] &&
 676                     nla_len(tb[CGW_CS_CRC8]) == CGW_CS_CRC8_LEN) {
 677
 678                         struct cgw_csum_crc8 *c = (struct cgw_csum_crc8 *)\
 679                                 nla_data(tb[CGW_CS_CRC8]);
 680
 681                         err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
 682                                                  c->result_idx);
 683                         if (err)
 684                                 return err;
 685
 686                         nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
 687                                    CGW_CS_CRC8_LEN);
 688
 689                         /*
 690                          * select dedicated processing function to reduce
 691                          * runtime operations in receive hot path.
 692                          */
 693                         if (c->from_idx < 0 || c->to_idx < 0 ||
 694                             c->result_idx < 0)
 695                                 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
 696                         else if (c->from_idx <= c->to_idx)
 697                                 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
 698                         else
 699                                 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
 700                 }
 701
 702                 if (tb[CGW_CS_XOR] &&
 703                     nla_len(tb[CGW_CS_XOR]) == CGW_CS_XOR_LEN) {
 704
 705                         struct cgw_csum_xor *c = (struct cgw_csum_xor *)\
 706                                 nla_data(tb[CGW_CS_XOR]);
 707
 708                         err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
 709                                                  c->result_idx);
 710                         if (err)
 711                                 return err;
 712
 713                         nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
 714                                    CGW_CS_XOR_LEN);
 715
 716                         /*
 717                          * select dedicated processing function to reduce
 718                          * runtime operations in receive hot path.
 719                          */
 720                         if (c->from_idx < 0 || c->to_idx < 0 ||
 721                             c->result_idx < 0)
 722                                 mod->csumfunc.xor = cgw_csum_xor_rel;
 723                         else if (c->from_idx <= c->to_idx)
 724                                 mod->csumfunc.xor = cgw_csum_xor_pos;
 725                         else
 726                                 mod->csumfunc.xor = cgw_csum_xor_neg;
 727                 }
 728         }
 729
 730         if (gwtype == CGW_TYPE_CAN_CAN) {
 731
 732                 /* check CGW_TYPE_CAN_CAN specific attributes */
 733
 734                 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
 735                 memset(ccgw, 0, sizeof(*ccgw));
 736
 737                 /* check for can_filter in attributes */
 738                 if (tb[CGW_FILTER] &&
 739                     nla_len(tb[CGW_FILTER]) == sizeof(struct can_filter))
 740                         nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
 741                                    sizeof(struct can_filter));
 742
 743                 err = -ENODEV;
 744
 745                 /* specifying two interfaces is mandatory */
 746                 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
 747                         return err;
 748
 749                 if (nla_len(tb[CGW_SRC_IF]) == sizeof(u32))
 750                         nla_memcpy(&ccgw->src_idx, tb[CGW_SRC_IF],
 751                                    sizeof(u32));
 752
 753                 if (nla_len(tb[CGW_DST_IF]) == sizeof(u32))
 754                         nla_memcpy(&ccgw->dst_idx, tb[CGW_DST_IF],
 755                                    sizeof(u32));
 756
 757                 /* both indices set to 0 for flushing all routing entries */
 758                 if (!ccgw->src_idx && !ccgw->dst_idx)
 759                         return 0;
 760
 761                 /* only one index set to 0 is an error */
 762                 if (!ccgw->src_idx || !ccgw->dst_idx)
 763                         return err;
 764         }
 765
 766         /* add the checks for other gwtypes here */
 767
 768         return 0;
 769 }
 770
 771 static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 772                           void *arg)
 773 {
 774         struct rtcanmsg *r;
 775         struct cgw_job *gwj;
 776         int err = 0;
 777
 778         if (nlmsg_len(nlh) < sizeof(*r))
 779                 return -EINVAL;
 780
 781         r = nlmsg_data(nlh);
 782         if (r->can_family != AF_CAN)
 783                 return -EPFNOSUPPORT;
 784
 785         /* so far we only support CAN -> CAN routings */
 786         if (r->gwtype != CGW_TYPE_CAN_CAN)
 787                 return -EINVAL;
 788
 789         gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
 790         if (!gwj)
 791                 return -ENOMEM;
 792
 793         gwj->handled_frames = 0;
 794         gwj->dropped_frames = 0;
 795         gwj->flags = r->flags;
 796         gwj->gwtype = r->gwtype;
 797
 798         err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
 799         if (err < 0)
 800                 goto out;
 801
 802         err = -ENODEV;
 803
 804         /* ifindex == 0 is not allowed for job creation */
 805         if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
 806                 goto out;
 807
 808         gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
 809
 810         if (!gwj->src.dev)
 811                 goto out;
 812
 813         /* check for CAN netdev not using header_ops - see gw_rcv() */
 814         if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
 815                 goto put_src_out;
 816
 817         gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
 818
 819         if (!gwj->dst.dev)
 820                 goto put_src_out;
 821
 822         /* check for CAN netdev not using header_ops - see gw_rcv() */
 823         if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
 824                 goto put_src_dst_out;
 825
 826         ASSERT_RTNL();
 827
 828         err = cgw_register_filter(gwj);
 829         if (!err)
 830                 hlist_add_head_rcu(&gwj->list, &cgw_list);
 831
 832 put_src_dst_out:
 833         dev_put(gwj->dst.dev);
 834 put_src_out:
 835         dev_put(gwj->src.dev);
 836 out:
 837         if (err)
 838                 kmem_cache_free(cgw_cache, gwj);
 839
 840         return err;
 841 }
 842
 843 static void cgw_remove_all_jobs(void)
 844 {
 845         struct cgw_job *gwj = NULL;
 846         struct hlist_node *n, *nx;
 847
 848         ASSERT_RTNL();
 849
 850         hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 851                 hlist_del(&gwj->list);
 852                 cgw_unregister_filter(gwj);
 853                 kfree(gwj);
 854         }
 855 }
 856
 857 static int cgw_remove_job(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 858 {
 859         struct cgw_job *gwj = NULL;
 860         struct hlist_node *n, *nx;
 861         struct rtcanmsg *r;
 862         struct cf_mod mod;
 863         struct can_can_gw ccgw;
 864         int err = 0;
 865
 866         if (nlmsg_len(nlh) < sizeof(*r))
 867                 return -EINVAL;
 868
 869         r = nlmsg_data(nlh);
 870         if (r->can_family != AF_CAN)
 871                 return -EPFNOSUPPORT;
 872
 873         /* so far we only support CAN -> CAN routings */
 874         if (r->gwtype != CGW_TYPE_CAN_CAN)
 875                 return -EINVAL;
 876
 877         err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
 878         if (err < 0)
 879                 return err;
 880
 881         /* two interface indices both set to 0 => remove all entries */
 882         if (!ccgw.src_idx && !ccgw.dst_idx) {
 883                 cgw_remove_all_jobs();
 884                 return 0;
 885         }
 886
 887         err = -EINVAL;
 888
 889         ASSERT_RTNL();
 890
 891         /* remove only the first matching entry */
 892         hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 893
 894                 if (gwj->flags != r->flags)
 895                         continue;
 896
 897                 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
 898                         continue;
 899
 900                 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
 901                 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
 902                         continue;
 903
 904                 hlist_del(&gwj->list);
 905                 cgw_unregister_filter(gwj);
 906                 kfree(gwj);
 907                 err = 0;
 908                 break;
 909         }
 910
 911         return err;
 912 }
 913
 914 static __init int cgw_module_init(void)
 915 {
 916         printk(banner);
 917
 918         cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
 919                                       0, 0, NULL);
 920
 921         if (!cgw_cache)
 922                 return -ENOMEM;
 923
 924         /* set notifier */
 925         notifier.notifier_call = cgw_notifier;
 926         register_netdevice_notifier(&notifier);
 927
 928         if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
 929                 unregister_netdevice_notifier(&notifier);
 930                 kmem_cache_destroy(cgw_cache);
 931                 return -ENOBUFS;
 932         }
 933
 934         /* Only the first call to __rtnl_register can fail */
 935         __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
 936         __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
 937
 938         return 0;
 939 }
 940
 941 static __exit void cgw_module_exit(void)
 942 {
 943         rtnl_unregister_all(PF_CAN);
 944
 945         unregister_netdevice_notifier(&notifier);
 946
 947         rtnl_lock();
 948         cgw_remove_all_jobs();
 949         rtnl_unlock();
 950
 951         rcu_barrier(); /* Wait for completion of call_rcu()'s */
 952
 953         kmem_cache_destroy(cgw_cache);
 954 }
 955
 956 module_init(cgw_module_init);
 957 module_exit(cgw_module_exit);