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 __initconst 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 static 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, int type,
 448                        u32 pid, u32 seq, int flags)
 449 {
 450         struct cgw_frame_mod mb;
 451         struct rtcanmsg *rtcan;
 452         struct nlmsghdr *nlh;
 453
 454         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
 455         if (!nlh)
 456                 return -EMSGSIZE;
 457
 458         rtcan = nlmsg_data(nlh);
 459         rtcan->can_family = AF_CAN;
 460         rtcan->gwtype = gwj->gwtype;
 461         rtcan->flags = gwj->flags;
 462
 463         /* add statistics if available */
 464
 465         if (gwj->handled_frames) {
 466                 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
 467                         goto cancel;
 468         }
 469
 470         if (gwj->dropped_frames) {
 471                 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
 472                         goto cancel;
 473         }
 474
 475         /* check non default settings of attributes */
 476
 477         if (gwj->mod.modtype.and) {
 478                 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
 479                 mb.modtype = gwj->mod.modtype.and;
 480                 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
 481                         goto cancel;
 482         }
 483
 484         if (gwj->mod.modtype.or) {
 485                 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
 486                 mb.modtype = gwj->mod.modtype.or;
 487                 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
 488                         goto cancel;
 489         }
 490
 491         if (gwj->mod.modtype.xor) {
 492                 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
 493                 mb.modtype = gwj->mod.modtype.xor;
 494                 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
 495                         goto cancel;
 496         }
 497
 498         if (gwj->mod.modtype.set) {
 499                 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
 500                 mb.modtype = gwj->mod.modtype.set;
 501                 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
 502                         goto cancel;
 503         }
 504
 505         if (gwj->mod.csumfunc.crc8) {
 506                 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
 507                             &gwj->mod.csum.crc8) < 0)
 508                         goto cancel;
 509         }
 510
 511         if (gwj->mod.csumfunc.xor) {
 512                 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
 513                             &gwj->mod.csum.xor) < 0)
 514                         goto cancel;
 515         }
 516
 517         if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
 518
 519                 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
 520                         if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
 521                                     &gwj->ccgw.filter) < 0)
 522                                 goto cancel;
 523                 }
 524
 525                 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
 526                         goto cancel;
 527
 528                 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
 529                         goto cancel;
 530         }
 531
 532         return nlmsg_end(skb, nlh);
 533
 534 cancel:
 535         nlmsg_cancel(skb, nlh);
 536         return -EMSGSIZE;
 537 }
 538
 539 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
 540 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
 541 {
 542         struct cgw_job *gwj = NULL;
 543         struct hlist_node *n;
 544         int idx = 0;
 545         int s_idx = cb->args[0];
 546
 547         rcu_read_lock();
 548         hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
 549                 if (idx < s_idx)
 550                         goto cont;
 551
 552                 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
 553                     cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
 554                         break;
 555 cont:
 556                 idx++;
 557         }
 558         rcu_read_unlock();
 559
 560         cb->args[0] = idx;
 561
 562         return skb->len;
 563 }
 564
 565 static const struct nla_policy cgw_policy[CGW_MAX+1] = {
 566         [CGW_MOD_AND]   = { .len = sizeof(struct cgw_frame_mod) },
 567         [CGW_MOD_OR]    = { .len = sizeof(struct cgw_frame_mod) },
 568         [CGW_MOD_XOR]   = { .len = sizeof(struct cgw_frame_mod) },
 569         [CGW_MOD_SET]   = { .len = sizeof(struct cgw_frame_mod) },
 570         [CGW_CS_XOR]    = { .len = sizeof(struct cgw_csum_xor) },
 571         [CGW_CS_CRC8]   = { .len = sizeof(struct cgw_csum_crc8) },
 572         [CGW_SRC_IF]    = { .type = NLA_U32 },
 573         [CGW_DST_IF]    = { .type = NLA_U32 },
 574         [CGW_FILTER]    = { .len = sizeof(struct can_filter) },
 575 };
 576
 577 /* check for common and gwtype specific attributes */
 578 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
 579                           u8 gwtype, void *gwtypeattr)
 580 {
 581         struct nlattr *tb[CGW_MAX+1];
 582         struct cgw_frame_mod mb;
 583         int modidx = 0;
 584         int err = 0;
 585
 586         /* initialize modification & checksum data space */
 587         memset(mod, 0, sizeof(*mod));
 588
 589         err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
 590                           cgw_policy);
 591         if (err < 0)
 592                 return err;
 593
 594         /* check for AND/OR/XOR/SET modifications */
 595
 596         if (tb[CGW_MOD_AND]) {
 597                 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
 598
 599                 canframecpy(&mod->modframe.and, &mb.cf);
 600                 mod->modtype.and = mb.modtype;
 601
 602                 if (mb.modtype & CGW_MOD_ID)
 603                         mod->modfunc[modidx++] = mod_and_id;
 604
 605                 if (mb.modtype & CGW_MOD_DLC)
 606                         mod->modfunc[modidx++] = mod_and_dlc;
 607
 608                 if (mb.modtype & CGW_MOD_DATA)
 609                         mod->modfunc[modidx++] = mod_and_data;
 610         }
 611
 612         if (tb[CGW_MOD_OR]) {
 613                 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
 614
 615                 canframecpy(&mod->modframe.or, &mb.cf);
 616                 mod->modtype.or = mb.modtype;
 617
 618                 if (mb.modtype & CGW_MOD_ID)
 619                         mod->modfunc[modidx++] = mod_or_id;
 620
 621                 if (mb.modtype & CGW_MOD_DLC)
 622                         mod->modfunc[modidx++] = mod_or_dlc;
 623
 624                 if (mb.modtype & CGW_MOD_DATA)
 625                         mod->modfunc[modidx++] = mod_or_data;
 626         }
 627
 628         if (tb[CGW_MOD_XOR]) {
 629                 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
 630
 631                 canframecpy(&mod->modframe.xor, &mb.cf);
 632                 mod->modtype.xor = mb.modtype;
 633
 634                 if (mb.modtype & CGW_MOD_ID)
 635                         mod->modfunc[modidx++] = mod_xor_id;
 636
 637                 if (mb.modtype & CGW_MOD_DLC)
 638                         mod->modfunc[modidx++] = mod_xor_dlc;
 639
 640                 if (mb.modtype & CGW_MOD_DATA)
 641                         mod->modfunc[modidx++] = mod_xor_data;
 642         }
 643
 644         if (tb[CGW_MOD_SET]) {
 645                 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
 646
 647                 canframecpy(&mod->modframe.set, &mb.cf);
 648                 mod->modtype.set = mb.modtype;
 649
 650                 if (mb.modtype & CGW_MOD_ID)
 651                         mod->modfunc[modidx++] = mod_set_id;
 652
 653                 if (mb.modtype & CGW_MOD_DLC)
 654                         mod->modfunc[modidx++] = mod_set_dlc;
 655
 656                 if (mb.modtype & CGW_MOD_DATA)
 657                         mod->modfunc[modidx++] = mod_set_data;
 658         }
 659
 660         /* check for checksum operations after CAN frame modifications */
 661         if (modidx) {
 662
 663                 if (tb[CGW_CS_CRC8]) {
 664                         struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
 665
 666                         err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
 667                                                  c->result_idx);
 668                         if (err)
 669                                 return err;
 670
 671                         nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
 672                                    CGW_CS_CRC8_LEN);
 673
 674                         /*
 675                          * select dedicated processing function to reduce
 676                          * runtime operations in receive hot path.
 677                          */
 678                         if (c->from_idx < 0 || c->to_idx < 0 ||
 679                             c->result_idx < 0)
 680                                 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
 681                         else if (c->from_idx <= c->to_idx)
 682                                 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
 683                         else
 684                                 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
 685                 }
 686
 687                 if (tb[CGW_CS_XOR]) {
 688                         struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
 689
 690                         err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
 691                                                  c->result_idx);
 692                         if (err)
 693                                 return err;
 694
 695                         nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
 696                                    CGW_CS_XOR_LEN);
 697
 698                         /*
 699                          * select dedicated processing function to reduce
 700                          * runtime operations in receive hot path.
 701                          */
 702                         if (c->from_idx < 0 || c->to_idx < 0 ||
 703                             c->result_idx < 0)
 704                                 mod->csumfunc.xor = cgw_csum_xor_rel;
 705                         else if (c->from_idx <= c->to_idx)
 706                                 mod->csumfunc.xor = cgw_csum_xor_pos;
 707                         else
 708                                 mod->csumfunc.xor = cgw_csum_xor_neg;
 709                 }
 710         }
 711
 712         if (gwtype == CGW_TYPE_CAN_CAN) {
 713
 714                 /* check CGW_TYPE_CAN_CAN specific attributes */
 715
 716                 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
 717                 memset(ccgw, 0, sizeof(*ccgw));
 718
 719                 /* check for can_filter in attributes */
 720                 if (tb[CGW_FILTER])
 721                         nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
 722                                    sizeof(struct can_filter));
 723
 724                 err = -ENODEV;
 725
 726                 /* specifying two interfaces is mandatory */
 727                 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
 728                         return err;
 729
 730                 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
 731                 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
 732
 733                 /* both indices set to 0 for flushing all routing entries */
 734                 if (!ccgw->src_idx && !ccgw->dst_idx)
 735                         return 0;
 736
 737                 /* only one index set to 0 is an error */
 738                 if (!ccgw->src_idx || !ccgw->dst_idx)
 739                         return err;
 740         }
 741
 742         /* add the checks for other gwtypes here */
 743
 744         return 0;
 745 }
 746
 747 static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 748                           void *arg)
 749 {
 750         struct rtcanmsg *r;
 751         struct cgw_job *gwj;
 752         int err = 0;
 753
 754         if (nlmsg_len(nlh) < sizeof(*r))
 755                 return -EINVAL;
 756
 757         r = nlmsg_data(nlh);
 758         if (r->can_family != AF_CAN)
 759                 return -EPFNOSUPPORT;
 760
 761         /* so far we only support CAN -> CAN routings */
 762         if (r->gwtype != CGW_TYPE_CAN_CAN)
 763                 return -EINVAL;
 764
 765         gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
 766         if (!gwj)
 767                 return -ENOMEM;
 768
 769         gwj->handled_frames = 0;
 770         gwj->dropped_frames = 0;
 771         gwj->flags = r->flags;
 772         gwj->gwtype = r->gwtype;
 773
 774         err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
 775         if (err < 0)
 776                 goto out;
 777
 778         err = -ENODEV;
 779
 780         /* ifindex == 0 is not allowed for job creation */
 781         if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
 782                 goto out;
 783
 784         gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
 785
 786         if (!gwj->src.dev)
 787                 goto out;
 788
 789         /* check for CAN netdev not using header_ops - see gw_rcv() */
 790         if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
 791                 goto put_src_out;
 792
 793         gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
 794
 795         if (!gwj->dst.dev)
 796                 goto put_src_out;
 797
 798         /* check for CAN netdev not using header_ops - see gw_rcv() */
 799         if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
 800                 goto put_src_dst_out;
 801
 802         ASSERT_RTNL();
 803
 804         err = cgw_register_filter(gwj);
 805         if (!err)
 806                 hlist_add_head_rcu(&gwj->list, &cgw_list);
 807
 808 put_src_dst_out:
 809         dev_put(gwj->dst.dev);
 810 put_src_out:
 811         dev_put(gwj->src.dev);
 812 out:
 813         if (err)
 814                 kmem_cache_free(cgw_cache, gwj);
 815
 816         return err;
 817 }
 818
 819 static void cgw_remove_all_jobs(void)
 820 {
 821         struct cgw_job *gwj = NULL;
 822         struct hlist_node *n, *nx;
 823
 824         ASSERT_RTNL();
 825
 826         hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 827                 hlist_del(&gwj->list);
 828                 cgw_unregister_filter(gwj);
 829                 kfree(gwj);
 830         }
 831 }
 832
 833 static int cgw_remove_job(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 834 {
 835         struct cgw_job *gwj = NULL;
 836         struct hlist_node *n, *nx;
 837         struct rtcanmsg *r;
 838         struct cf_mod mod;
 839         struct can_can_gw ccgw;
 840         int err = 0;
 841
 842         if (nlmsg_len(nlh) < sizeof(*r))
 843                 return -EINVAL;
 844
 845         r = nlmsg_data(nlh);
 846         if (r->can_family != AF_CAN)
 847                 return -EPFNOSUPPORT;
 848
 849         /* so far we only support CAN -> CAN routings */
 850         if (r->gwtype != CGW_TYPE_CAN_CAN)
 851                 return -EINVAL;
 852
 853         err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
 854         if (err < 0)
 855                 return err;
 856
 857         /* two interface indices both set to 0 => remove all entries */
 858         if (!ccgw.src_idx && !ccgw.dst_idx) {
 859                 cgw_remove_all_jobs();
 860                 return 0;
 861         }
 862
 863         err = -EINVAL;
 864
 865         ASSERT_RTNL();
 866
 867         /* remove only the first matching entry */
 868         hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
 869
 870                 if (gwj->flags != r->flags)
 871                         continue;
 872
 873                 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
 874                         continue;
 875
 876                 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
 877                 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
 878                         continue;
 879
 880                 hlist_del(&gwj->list);
 881                 cgw_unregister_filter(gwj);
 882                 kfree(gwj);
 883                 err = 0;
 884                 break;
 885         }
 886
 887         return err;
 888 }
 889
 890 static __init int cgw_module_init(void)
 891 {
 892         printk(banner);
 893
 894         cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
 895                                       0, 0, NULL);
 896
 897         if (!cgw_cache)
 898                 return -ENOMEM;
 899
 900         /* set notifier */
 901         notifier.notifier_call = cgw_notifier;
 902         register_netdevice_notifier(&notifier);
 903
 904         if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
 905                 unregister_netdevice_notifier(&notifier);
 906                 kmem_cache_destroy(cgw_cache);
 907                 return -ENOBUFS;
 908         }
 909
 910         /* Only the first call to __rtnl_register can fail */
 911         __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
 912         __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
 913
 914         return 0;
 915 }
 916
 917 static __exit void cgw_module_exit(void)
 918 {
 919         rtnl_unregister_all(PF_CAN);
 920
 921         unregister_netdevice_notifier(&notifier);
 922
 923         rtnl_lock();
 924         cgw_remove_all_jobs();
 925         rtnl_unlock();
 926
 927         rcu_barrier(); /* Wait for completion of call_rcu()'s */
 928
 929         kmem_cache_destroy(cgw_cache);
 930 }
 931
 932 module_init(cgw_module_init);
 933 module_exit(cgw_module_exit);