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   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/capability.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/kmod.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22
  23 #include <asm/uaccess.h>
  24 #include <linux/mutex.h>
  25
  26 #include <linux/netfilter/x_tables.h>
  27 #include <linux/netfilter_arp/arp_tables.h>
  28
  29 MODULE_LICENSE("GPL");
  30 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  31 MODULE_DESCRIPTION("arptables core");
  32
  33 /*#define DEBUG_ARP_TABLES*/
  34 /*#define DEBUG_ARP_TABLES_USER*/
  35
  36 #ifdef DEBUG_ARP_TABLES
  37 #define dprintf(format, args...)  printk(format , ## args)
  38 #else
  39 #define dprintf(format, args...)
  40 #endif
  41
  42 #ifdef DEBUG_ARP_TABLES_USER
  43 #define duprintf(format, args...) printk(format , ## args)
  44 #else
  45 #define duprintf(format, args...)
  46 #endif
  47
  48 #ifdef CONFIG_NETFILTER_DEBUG
  49 #define ARP_NF_ASSERT(x)                                        \
  50 do {                                                            \
  51         if (!(x))                                               \
  52                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  53                        __FUNCTION__, __FILE__, __LINE__);       \
  54 } while(0)
  55 #else
  56 #define ARP_NF_ASSERT(x)
  57 #endif
  58
  59 #include <linux/netfilter_ipv4/listhelp.h>
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       char *hdr_addr, int len)
  63 {
  64         int i, ret;
  65
  66         if (len > ARPT_DEV_ADDR_LEN_MAX)
  67                 len = ARPT_DEV_ADDR_LEN_MAX;
  68
  69         ret = 0;
  70         for (i = 0; i < len; i++)
  71                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  72
  73         return (ret != 0);
  74 }
  75
  76 /* Returns whether packet matches rule or not. */
  77 static inline int arp_packet_match(const struct arphdr *arphdr,
  78                                    struct net_device *dev,
  79                                    const char *indev,
  80                                    const char *outdev,
  81                                    const struct arpt_arp *arpinfo)
  82 {
  83         char *arpptr = (char *)(arphdr + 1);
  84         char *src_devaddr, *tgt_devaddr;
  85         u32 src_ipaddr, tgt_ipaddr;
  86         int i, ret;
  87
  88 #define FWINV(bool,invflg) ((bool) ^ !!(arpinfo->invflags & invflg))
  89
  90         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
  91                   ARPT_INV_ARPOP)) {
  92                 dprintf("ARP operation field mismatch.\n");
  93                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
  94                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
  95                 return 0;
  96         }
  97
  98         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
  99                   ARPT_INV_ARPHRD)) {
 100                 dprintf("ARP hardware address format mismatch.\n");
 101                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 102                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 103                 return 0;
 104         }
 105
 106         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 107                   ARPT_INV_ARPPRO)) {
 108                 dprintf("ARP protocol address format mismatch.\n");
 109                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 110                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 111                 return 0;
 112         }
 113
 114         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 115                   ARPT_INV_ARPHLN)) {
 116                 dprintf("ARP hardware address length mismatch.\n");
 117                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 118                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 119                 return 0;
 120         }
 121
 122         src_devaddr = arpptr;
 123         arpptr += dev->addr_len;
 124         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 125         arpptr += sizeof(u32);
 126         tgt_devaddr = arpptr;
 127         arpptr += dev->addr_len;
 128         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 129
 130         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 131                   ARPT_INV_SRCDEVADDR) ||
 132             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 133                   ARPT_INV_TGTDEVADDR)) {
 134                 dprintf("Source or target device address mismatch.\n");
 135
 136                 return 0;
 137         }
 138
 139         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 140                   ARPT_INV_SRCIP) ||
 141             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 142                   ARPT_INV_TGTIP)) {
 143                 dprintf("Source or target IP address mismatch.\n");
 144
 145                 dprintf("SRC: %u.%u.%u.%u. Mask: %u.%u.%u.%u. Target: %u.%u.%u.%u.%s\n",
 146                         NIPQUAD(src_ipaddr),
 147                         NIPQUAD(arpinfo->smsk.s_addr),
 148                         NIPQUAD(arpinfo->src.s_addr),
 149                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 150                 dprintf("TGT: %u.%u.%u.%u Mask: %u.%u.%u.%u Target: %u.%u.%u.%u.%s\n",
 151                         NIPQUAD(tgt_ipaddr),
 152                         NIPQUAD(arpinfo->tmsk.s_addr),
 153                         NIPQUAD(arpinfo->tgt.s_addr),
 154                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 155                 return 0;
 156         }
 157
 158         /* Look for ifname matches.  */
 159         for (i = 0, ret = 0; i < IFNAMSIZ; i++) {
 160                 ret |= (indev[i] ^ arpinfo->iniface[i])
 161                         & arpinfo->iniface_mask[i];
 162         }
 163
 164         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 165                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 166                         indev, arpinfo->iniface,
 167                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 168                 return 0;
 169         }
 170
 171         for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
 172                 unsigned long odev;
 173                 memcpy(&odev, outdev + i*sizeof(unsigned long),
 174                        sizeof(unsigned long));
 175                 ret |= (odev
 176                         ^ ((const unsigned long *)arpinfo->outiface)[i])
 177                         & ((const unsigned long *)arpinfo->outiface_mask)[i];
 178         }
 179
 180         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 181                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 182                         outdev, arpinfo->outiface,
 183                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 184                 return 0;
 185         }
 186
 187         return 1;
 188 }
 189
 190 static inline int arp_checkentry(const struct arpt_arp *arp)
 191 {
 192         if (arp->flags & ~ARPT_F_MASK) {
 193                 duprintf("Unknown flag bits set: %08X\n",
 194                          arp->flags & ~ARPT_F_MASK);
 195                 return 0;
 196         }
 197         if (arp->invflags & ~ARPT_INV_MASK) {
 198                 duprintf("Unknown invflag bits set: %08X\n",
 199                          arp->invflags & ~ARPT_INV_MASK);
 200                 return 0;
 201         }
 202
 203         return 1;
 204 }
 205
 206 static unsigned int arpt_error(struct sk_buff **pskb,
 207                                const struct net_device *in,
 208                                const struct net_device *out,
 209                                unsigned int hooknum,
 210                                const struct xt_target *target,
 211                                const void *targinfo,
 212                                void *userinfo)
 213 {
 214         if (net_ratelimit())
 215                 printk("arp_tables: error: '%s'\n", (char *)targinfo);
 216
 217         return NF_DROP;
 218 }
 219
 220 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 221 {
 222         return (struct arpt_entry *)(base + offset);
 223 }
 224
 225 unsigned int arpt_do_table(struct sk_buff **pskb,
 226                            unsigned int hook,
 227                            const struct net_device *in,
 228                            const struct net_device *out,
 229                            struct arpt_table *table,
 230                            void *userdata)
 231 {
 232         static const char nulldevname[IFNAMSIZ];
 233         unsigned int verdict = NF_DROP;
 234         struct arphdr *arp;
 235         int hotdrop = 0;
 236         struct arpt_entry *e, *back;
 237         const char *indev, *outdev;
 238         void *table_base;
 239         struct xt_table_info *private = table->private;
 240
 241         /* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
 242         if (!pskb_may_pull((*pskb), (sizeof(struct arphdr) +
 243                                      (2 * (*pskb)->dev->addr_len) +
 244                                      (2 * sizeof(u32)))))
 245                 return NF_DROP;
 246
 247         indev = in ? in->name : nulldevname;
 248         outdev = out ? out->name : nulldevname;
 249
 250         read_lock_bh(&table->lock);
 251         table_base = (void *)private->entries[smp_processor_id()];
 252         e = get_entry(table_base, private->hook_entry[hook]);
 253         back = get_entry(table_base, private->underflow[hook]);
 254
 255         arp = (*pskb)->nh.arph;
 256         do {
 257                 if (arp_packet_match(arp, (*pskb)->dev, indev, outdev, &e->arp)) {
 258                         struct arpt_entry_target *t;
 259                         int hdr_len;
 260
 261                         hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 262                                 (2 * (*pskb)->dev->addr_len);
 263                         ADD_COUNTER(e->counters, hdr_len, 1);
 264
 265                         t = arpt_get_target(e);
 266
 267                         /* Standard target? */
 268                         if (!t->u.kernel.target->target) {
 269                                 int v;
 270
 271                                 v = ((struct arpt_standard_target *)t)->verdict;
 272                                 if (v < 0) {
 273                                         /* Pop from stack? */
 274                                         if (v != ARPT_RETURN) {
 275                                                 verdict = (unsigned)(-v) - 1;
 276                                                 break;
 277                                         }
 278                                         e = back;
 279                                         back = get_entry(table_base,
 280                                                          back->comefrom);
 281                                         continue;
 282                                 }
 283                                 if (table_base + v
 284                                     != (void *)e + e->next_offset) {
 285                                         /* Save old back ptr in next entry */
 286                                         struct arpt_entry *next
 287                                                 = (void *)e + e->next_offset;
 288                                         next->comefrom =
 289                                                 (void *)back - table_base;
 290
 291                                         /* set back pointer to next entry */
 292                                         back = next;
 293                                 }
 294
 295                                 e = get_entry(table_base, v);
 296                         } else {
 297                                 /* Targets which reenter must return
 298                                  * abs. verdicts
 299                                  */
 300                                 verdict = t->u.kernel.target->target(pskb,
 301                                                                      in, out,
 302                                                                      hook,
 303                                                                      t->u.kernel.target,
 304                                                                      t->data,
 305                                                                      userdata);
 306
 307                                 /* Target might have changed stuff. */
 308                                 arp = (*pskb)->nh.arph;
 309
 310                                 if (verdict == ARPT_CONTINUE)
 311                                         e = (void *)e + e->next_offset;
 312                                 else
 313                                         /* Verdict */
 314                                         break;
 315                         }
 316                 } else {
 317                         e = (void *)e + e->next_offset;
 318                 }
 319         } while (!hotdrop);
 320         read_unlock_bh(&table->lock);
 321
 322         if (hotdrop)
 323                 return NF_DROP;
 324         else
 325                 return verdict;
 326 }
 327
 328 /* All zeroes == unconditional rule. */
 329 static inline int unconditional(const struct arpt_arp *arp)
 330 {
 331         unsigned int i;
 332
 333         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 334                 if (((__u32 *)arp)[i])
 335                         return 0;
 336
 337         return 1;
 338 }
 339
 340 /* Figures out from what hook each rule can be called: returns 0 if
 341  * there are loops.  Puts hook bitmask in comefrom.
 342  */
 343 static int mark_source_chains(struct xt_table_info *newinfo,
 344                               unsigned int valid_hooks, void *entry0)
 345 {
 346         unsigned int hook;
 347
 348         /* No recursion; use packet counter to save back ptrs (reset
 349          * to 0 as we leave), and comefrom to save source hook bitmask.
 350          */
 351         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 352                 unsigned int pos = newinfo->hook_entry[hook];
 353                 struct arpt_entry *e
 354                         = (struct arpt_entry *)(entry0 + pos);
 355
 356                 if (!(valid_hooks & (1 << hook)))
 357                         continue;
 358
 359                 /* Set initial back pointer. */
 360                 e->counters.pcnt = pos;
 361
 362                 for (;;) {
 363                         struct arpt_standard_target *t
 364                                 = (void *)arpt_get_target(e);
 365
 366                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 367                                 printk("arptables: loop hook %u pos %u %08X.\n",
 368                                        hook, pos, e->comefrom);
 369                                 return 0;
 370                         }
 371                         e->comefrom
 372                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 373
 374                         /* Unconditional return/END. */
 375                         if (e->target_offset == sizeof(struct arpt_entry)
 376                             && (strcmp(t->target.u.user.name,
 377                                        ARPT_STANDARD_TARGET) == 0)
 378                             && t->verdict < 0
 379                             && unconditional(&e->arp)) {
 380                                 unsigned int oldpos, size;
 381
 382                                 /* Return: backtrack through the last
 383                                  * big jump.
 384                                  */
 385                                 do {
 386                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 387                                         oldpos = pos;
 388                                         pos = e->counters.pcnt;
 389                                         e->counters.pcnt = 0;
 390
 391                                         /* We're at the start. */
 392                                         if (pos == oldpos)
 393                                                 goto next;
 394
 395                                         e = (struct arpt_entry *)
 396                                                 (entry0 + pos);
 397                                 } while (oldpos == pos + e->next_offset);
 398
 399                                 /* Move along one */
 400                                 size = e->next_offset;
 401                                 e = (struct arpt_entry *)
 402                                         (entry0 + pos + size);
 403                                 e->counters.pcnt = pos;
 404                                 pos += size;
 405                         } else {
 406                                 int newpos = t->verdict;
 407
 408                                 if (strcmp(t->target.u.user.name,
 409                                            ARPT_STANDARD_TARGET) == 0
 410                                     && newpos >= 0) {
 411                                         /* This a jump; chase it. */
 412                                         duprintf("Jump rule %u -> %u\n",
 413                                                  pos, newpos);
 414                                 } else {
 415                                         /* ... this is a fallthru */
 416                                         newpos = pos + e->next_offset;
 417                                 }
 418                                 e = (struct arpt_entry *)
 419                                         (entry0 + newpos);
 420                                 e->counters.pcnt = pos;
 421                                 pos = newpos;
 422                         }
 423                 }
 424                 next:
 425                 duprintf("Finished chain %u\n", hook);
 426         }
 427         return 1;
 428 }
 429
 430 static inline int standard_check(const struct arpt_entry_target *t,
 431                                  unsigned int max_offset)
 432 {
 433         struct arpt_standard_target *targ = (void *)t;
 434
 435         /* Check standard info. */
 436         if (t->u.target_size
 437             != ARPT_ALIGN(sizeof(struct arpt_standard_target))) {
 438                 duprintf("arpt_standard_check: target size %u != %Zu\n",
 439                          t->u.target_size,
 440                          ARPT_ALIGN(sizeof(struct arpt_standard_target)));
 441                 return 0;
 442         }
 443
 444         if (targ->verdict >= 0
 445             && targ->verdict > max_offset - sizeof(struct arpt_entry)) {
 446                 duprintf("arpt_standard_check: bad verdict (%i)\n",
 447                          targ->verdict);
 448                 return 0;
 449         }
 450
 451         if (targ->verdict < -NF_MAX_VERDICT - 1) {
 452                 duprintf("arpt_standard_check: bad negative verdict (%i)\n",
 453                          targ->verdict);
 454                 return 0;
 455         }
 456         return 1;
 457 }
 458
 459 static struct arpt_target arpt_standard_target;
 460
 461 static inline int check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 462                               unsigned int *i)
 463 {
 464         struct arpt_entry_target *t;
 465         struct arpt_target *target;
 466         int ret;
 467
 468         if (!arp_checkentry(&e->arp)) {
 469                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 470                 return -EINVAL;
 471         }
 472
 473         t = arpt_get_target(e);
 474         target = try_then_request_module(xt_find_target(NF_ARP, t->u.user.name,
 475                                                         t->u.user.revision),
 476                                          "arpt_%s", t->u.user.name);
 477         if (IS_ERR(target) || !target) {
 478                 duprintf("check_entry: `%s' not found\n", t->u.user.name);
 479                 ret = target ? PTR_ERR(target) : -ENOENT;
 480                 goto out;
 481         }
 482         t->u.kernel.target = target;
 483
 484         ret = xt_check_target(target, NF_ARP, t->u.target_size - sizeof(*t),
 485                               name, e->comefrom, 0, 0);
 486         if (ret)
 487                 goto err;
 488
 489         if (t->u.kernel.target == &arpt_standard_target) {
 490                 if (!standard_check(t, size)) {
 491                         ret = -EINVAL;
 492                         goto out;
 493                 }
 494         } else if (t->u.kernel.target->checkentry
 495                    && !t->u.kernel.target->checkentry(name, e, target, t->data,
 496                                                       t->u.target_size
 497                                                       - sizeof(*t),
 498                                                       e->comefrom)) {
 499                 duprintf("arp_tables: check failed for `%s'.\n",
 500                          t->u.kernel.target->name);
 501                 ret = -EINVAL;
 502                 goto err;
 503         }
 504
 505         (*i)++;
 506         return 0;
 507 err:
 508         module_put(t->u.kernel.target->me);
 509 out:
 510         return ret;
 511 }
 512
 513 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 514                                              struct xt_table_info *newinfo,
 515                                              unsigned char *base,
 516                                              unsigned char *limit,
 517                                              const unsigned int *hook_entries,
 518                                              const unsigned int *underflows,
 519                                              unsigned int *i)
 520 {
 521         unsigned int h;
 522
 523         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 524             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 525                 duprintf("Bad offset %p\n", e);
 526                 return -EINVAL;
 527         }
 528
 529         if (e->next_offset
 530             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 531                 duprintf("checking: element %p size %u\n",
 532                          e, e->next_offset);
 533                 return -EINVAL;
 534         }
 535
 536         /* Check hooks & underflows */
 537         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 538                 if ((unsigned char *)e - base == hook_entries[h])
 539                         newinfo->hook_entry[h] = hook_entries[h];
 540                 if ((unsigned char *)e - base == underflows[h])
 541                         newinfo->underflow[h] = underflows[h];
 542         }
 543
 544         /* FIXME: underflows must be unconditional, standard verdicts
 545            < 0 (not ARPT_RETURN). --RR */
 546
 547         /* Clear counters and comefrom */
 548         e->counters = ((struct xt_counters) { 0, 0 });
 549         e->comefrom = 0;
 550
 551         (*i)++;
 552         return 0;
 553 }
 554
 555 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 556 {
 557         struct arpt_entry_target *t;
 558
 559         if (i && (*i)-- == 0)
 560                 return 1;
 561
 562         t = arpt_get_target(e);
 563         if (t->u.kernel.target->destroy)
 564                 t->u.kernel.target->destroy(t->u.kernel.target, t->data,
 565                                             t->u.target_size - sizeof(*t));
 566         module_put(t->u.kernel.target->me);
 567         return 0;
 568 }
 569
 570 /* Checks and translates the user-supplied table segment (held in
 571  * newinfo).
 572  */
 573 static int translate_table(const char *name,
 574                            unsigned int valid_hooks,
 575                            struct xt_table_info *newinfo,
 576                            void *entry0,
 577                            unsigned int size,
 578                            unsigned int number,
 579                            const unsigned int *hook_entries,
 580                            const unsigned int *underflows)
 581 {
 582         unsigned int i;
 583         int ret;
 584
 585         newinfo->size = size;
 586         newinfo->number = number;
 587
 588         /* Init all hooks to impossible value. */
 589         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 590                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 591                 newinfo->underflow[i] = 0xFFFFFFFF;
 592         }
 593
 594         duprintf("translate_table: size %u\n", newinfo->size);
 595         i = 0;
 596
 597         /* Walk through entries, checking offsets. */
 598         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 599                                  check_entry_size_and_hooks,
 600                                  newinfo,
 601                                  entry0,
 602                                  entry0 + size,
 603                                  hook_entries, underflows, &i);
 604         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 605         if (ret != 0)
 606                 return ret;
 607
 608         if (i != number) {
 609                 duprintf("translate_table: %u not %u entries\n",
 610                          i, number);
 611                 return -EINVAL;
 612         }
 613
 614         /* Check hooks all assigned */
 615         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 616                 /* Only hooks which are valid */
 617                 if (!(valid_hooks & (1 << i)))
 618                         continue;
 619                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 620                         duprintf("Invalid hook entry %u %u\n",
 621                                  i, hook_entries[i]);
 622                         return -EINVAL;
 623                 }
 624                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 625                         duprintf("Invalid underflow %u %u\n",
 626                                  i, underflows[i]);
 627                         return -EINVAL;
 628                 }
 629         }
 630
 631         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 632                 duprintf("Looping hook\n");
 633                 return -ELOOP;
 634         }
 635
 636         /* Finally, each sanity check must pass */
 637         i = 0;
 638         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 639                                  check_entry, name, size, &i);
 640
 641         if (ret != 0) {
 642                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 643                                    cleanup_entry, &i);
 644                 return ret;
 645         }
 646
 647         /* And one copy for every other CPU */
 648         for_each_possible_cpu(i) {
 649                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 650                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 651         }
 652
 653         return ret;
 654 }
 655
 656 /* Gets counters. */
 657 static inline int add_entry_to_counter(const struct arpt_entry *e,
 658                                        struct xt_counters total[],
 659                                        unsigned int *i)
 660 {
 661         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 662
 663         (*i)++;
 664         return 0;
 665 }
 666
 667 static inline int set_entry_to_counter(const struct arpt_entry *e,
 668                                        struct xt_counters total[],
 669                                        unsigned int *i)
 670 {
 671         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 672
 673         (*i)++;
 674         return 0;
 675 }
 676
 677 static void get_counters(const struct xt_table_info *t,
 678                          struct xt_counters counters[])
 679 {
 680         unsigned int cpu;
 681         unsigned int i;
 682         unsigned int curcpu;
 683
 684         /* Instead of clearing (by a previous call to memset())
 685          * the counters and using adds, we set the counters
 686          * with data used by 'current' CPU
 687          * We dont care about preemption here.
 688          */
 689         curcpu = raw_smp_processor_id();
 690
 691         i = 0;
 692         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 693                            t->size,
 694                            set_entry_to_counter,
 695                            counters,
 696                            &i);
 697
 698         for_each_possible_cpu(cpu) {
 699                 if (cpu == curcpu)
 700                         continue;
 701                 i = 0;
 702                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 703                                    t->size,
 704                                    add_entry_to_counter,
 705                                    counters,
 706                                    &i);
 707         }
 708 }
 709
 710 static int copy_entries_to_user(unsigned int total_size,
 711                                 struct arpt_table *table,
 712                                 void __user *userptr)
 713 {
 714         unsigned int off, num, countersize;
 715         struct arpt_entry *e;
 716         struct xt_counters *counters;
 717         struct xt_table_info *private = table->private;
 718         int ret = 0;
 719         void *loc_cpu_entry;
 720
 721         /* We need atomic snapshot of counters: rest doesn't change
 722          * (other than comefrom, which userspace doesn't care
 723          * about).
 724          */
 725         countersize = sizeof(struct xt_counters) * private->number;
 726         counters = vmalloc_node(countersize, numa_node_id());
 727
 728         if (counters == NULL)
 729                 return -ENOMEM;
 730
 731         /* First, sum counters... */
 732         write_lock_bh(&table->lock);
 733         get_counters(private, counters);
 734         write_unlock_bh(&table->lock);
 735
 736         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 737         /* ... then copy entire thing ... */
 738         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 739                 ret = -EFAULT;
 740                 goto free_counters;
 741         }
 742
 743         /* FIXME: use iterator macros --RR */
 744         /* ... then go back and fix counters and names */
 745         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 746                 struct arpt_entry_target *t;
 747
 748                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 749                 if (copy_to_user(userptr + off
 750                                  + offsetof(struct arpt_entry, counters),
 751                                  &counters[num],
 752                                  sizeof(counters[num])) != 0) {
 753                         ret = -EFAULT;
 754                         goto free_counters;
 755                 }
 756
 757                 t = arpt_get_target(e);
 758                 if (copy_to_user(userptr + off + e->target_offset
 759                                  + offsetof(struct arpt_entry_target,
 760                                             u.user.name),
 761                                  t->u.kernel.target->name,
 762                                  strlen(t->u.kernel.target->name)+1) != 0) {
 763                         ret = -EFAULT;
 764                         goto free_counters;
 765                 }
 766         }
 767
 768  free_counters:
 769         vfree(counters);
 770         return ret;
 771 }
 772
 773 static int get_entries(const struct arpt_get_entries *entries,
 774                        struct arpt_get_entries __user *uptr)
 775 {
 776         int ret;
 777         struct arpt_table *t;
 778
 779         t = xt_find_table_lock(NF_ARP, entries->name);
 780         if (t && !IS_ERR(t)) {
 781                 struct xt_table_info *private = t->private;
 782                 duprintf("t->private->number = %u\n",
 783                          private->number);
 784                 if (entries->size == private->size)
 785                         ret = copy_entries_to_user(private->size,
 786                                                    t, uptr->entrytable);
 787                 else {
 788                         duprintf("get_entries: I've got %u not %u!\n",
 789                                  private->size, entries->size);
 790                         ret = -EINVAL;
 791                 }
 792                 module_put(t->me);
 793                 xt_table_unlock(t);
 794         } else
 795                 ret = t ? PTR_ERR(t) : -ENOENT;
 796
 797         return ret;
 798 }
 799
 800 static int do_replace(void __user *user, unsigned int len)
 801 {
 802         int ret;
 803         struct arpt_replace tmp;
 804         struct arpt_table *t;
 805         struct xt_table_info *newinfo, *oldinfo;
 806         struct xt_counters *counters;
 807         void *loc_cpu_entry, *loc_cpu_old_entry;
 808
 809         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 810                 return -EFAULT;
 811
 812         /* Hack: Causes ipchains to give correct error msg --RR */
 813         if (len != sizeof(tmp) + tmp.size)
 814                 return -ENOPROTOOPT;
 815
 816         /* overflow check */
 817         if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
 818                         SMP_CACHE_BYTES)
 819                 return -ENOMEM;
 820         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 821                 return -ENOMEM;
 822
 823         newinfo = xt_alloc_table_info(tmp.size);
 824         if (!newinfo)
 825                 return -ENOMEM;
 826
 827         /* choose the copy that is on our node/cpu */
 828         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
 829         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 830                            tmp.size) != 0) {
 831                 ret = -EFAULT;
 832                 goto free_newinfo;
 833         }
 834
 835         counters = vmalloc(tmp.num_counters * sizeof(struct xt_counters));
 836         if (!counters) {
 837                 ret = -ENOMEM;
 838                 goto free_newinfo;
 839         }
 840
 841         ret = translate_table(tmp.name, tmp.valid_hooks,
 842                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
 843                               tmp.hook_entry, tmp.underflow);
 844         if (ret != 0)
 845                 goto free_newinfo_counters;
 846
 847         duprintf("arp_tables: Translated table\n");
 848
 849         t = try_then_request_module(xt_find_table_lock(NF_ARP, tmp.name),
 850                                     "arptable_%s", tmp.name);
 851         if (!t || IS_ERR(t)) {
 852                 ret = t ? PTR_ERR(t) : -ENOENT;
 853                 goto free_newinfo_counters_untrans;
 854         }
 855
 856         /* You lied! */
 857         if (tmp.valid_hooks != t->valid_hooks) {
 858                 duprintf("Valid hook crap: %08X vs %08X\n",
 859                          tmp.valid_hooks, t->valid_hooks);
 860                 ret = -EINVAL;
 861                 goto put_module;
 862         }
 863
 864         oldinfo = xt_replace_table(t, tmp.num_counters, newinfo, &ret);
 865         if (!oldinfo)
 866                 goto put_module;
 867
 868         /* Update module usage count based on number of rules */
 869         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
 870                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
 871         if ((oldinfo->number > oldinfo->initial_entries) ||
 872             (newinfo->number <= oldinfo->initial_entries))
 873                 module_put(t->me);
 874         if ((oldinfo->number > oldinfo->initial_entries) &&
 875             (newinfo->number <= oldinfo->initial_entries))
 876                 module_put(t->me);
 877
 878         /* Get the old counters. */
 879         get_counters(oldinfo, counters);
 880         /* Decrease module usage counts and free resource */
 881         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
 882         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,NULL);
 883
 884         xt_free_table_info(oldinfo);
 885         if (copy_to_user(tmp.counters, counters,
 886                          sizeof(struct xt_counters) * tmp.num_counters) != 0)
 887                 ret = -EFAULT;
 888         vfree(counters);
 889         xt_table_unlock(t);
 890         return ret;
 891
 892  put_module:
 893         module_put(t->me);
 894         xt_table_unlock(t);
 895  free_newinfo_counters_untrans:
 896         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
 897  free_newinfo_counters:
 898         vfree(counters);
 899  free_newinfo:
 900         xt_free_table_info(newinfo);
 901         return ret;
 902 }
 903
 904 /* We're lazy, and add to the first CPU; overflow works its fey magic
 905  * and everything is OK.
 906  */
 907 static inline int add_counter_to_entry(struct arpt_entry *e,
 908                                        const struct xt_counters addme[],
 909                                        unsigned int *i)
 910 {
 911
 912         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
 913
 914         (*i)++;
 915         return 0;
 916 }
 917
 918 static int do_add_counters(void __user *user, unsigned int len)
 919 {
 920         unsigned int i;
 921         struct xt_counters_info tmp, *paddc;
 922         struct arpt_table *t;
 923         struct xt_table_info *private;
 924         int ret = 0;
 925         void *loc_cpu_entry;
 926
 927         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 928                 return -EFAULT;
 929
 930         if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct xt_counters))
 931                 return -EINVAL;
 932
 933         paddc = vmalloc(len);
 934         if (!paddc)
 935                 return -ENOMEM;
 936
 937         if (copy_from_user(paddc, user, len) != 0) {
 938                 ret = -EFAULT;
 939                 goto free;
 940         }
 941
 942         t = xt_find_table_lock(NF_ARP, tmp.name);
 943         if (!t || IS_ERR(t)) {
 944                 ret = t ? PTR_ERR(t) : -ENOENT;
 945                 goto free;
 946         }
 947
 948         write_lock_bh(&t->lock);
 949         private = t->private;
 950         if (private->number != tmp.num_counters) {
 951                 ret = -EINVAL;
 952                 goto unlock_up_free;
 953         }
 954
 955         i = 0;
 956         /* Choose the copy that is on our node */
 957         loc_cpu_entry = private->entries[smp_processor_id()];
 958         ARPT_ENTRY_ITERATE(loc_cpu_entry,
 959                            private->size,
 960                            add_counter_to_entry,
 961                            paddc->counters,
 962                            &i);
 963  unlock_up_free:
 964         write_unlock_bh(&t->lock);
 965         xt_table_unlock(t);
 966         module_put(t->me);
 967  free:
 968         vfree(paddc);
 969
 970         return ret;
 971 }
 972
 973 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 974 {
 975         int ret;
 976
 977         if (!capable(CAP_NET_ADMIN))
 978                 return -EPERM;
 979
 980         switch (cmd) {
 981         case ARPT_SO_SET_REPLACE:
 982                 ret = do_replace(user, len);
 983                 break;
 984
 985         case ARPT_SO_SET_ADD_COUNTERS:
 986                 ret = do_add_counters(user, len);
 987                 break;
 988
 989         default:
 990                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
 991                 ret = -EINVAL;
 992         }
 993
 994         return ret;
 995 }
 996
 997 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
 998 {
 999         int ret;
1000
1001         if (!capable(CAP_NET_ADMIN))
1002                 return -EPERM;
1003
1004         switch (cmd) {
1005         case ARPT_SO_GET_INFO: {
1006                 char name[ARPT_TABLE_MAXNAMELEN];
1007                 struct arpt_table *t;
1008
1009                 if (*len != sizeof(struct arpt_getinfo)) {
1010                         duprintf("length %u != %Zu\n", *len,
1011                                  sizeof(struct arpt_getinfo));
1012                         ret = -EINVAL;
1013                         break;
1014                 }
1015
1016                 if (copy_from_user(name, user, sizeof(name)) != 0) {
1017                         ret = -EFAULT;
1018                         break;
1019                 }
1020                 name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
1021
1022                 t = try_then_request_module(xt_find_table_lock(NF_ARP, name),
1023                                             "arptable_%s", name);
1024                 if (t && !IS_ERR(t)) {
1025                         struct arpt_getinfo info;
1026                         struct xt_table_info *private = t->private;
1027
1028                         info.valid_hooks = t->valid_hooks;
1029                         memcpy(info.hook_entry, private->hook_entry,
1030                                sizeof(info.hook_entry));
1031                         memcpy(info.underflow, private->underflow,
1032                                sizeof(info.underflow));
1033                         info.num_entries = private->number;
1034                         info.size = private->size;
1035                         strcpy(info.name, name);
1036
1037                         if (copy_to_user(user, &info, *len) != 0)
1038                                 ret = -EFAULT;
1039                         else
1040                                 ret = 0;
1041                         xt_table_unlock(t);
1042                         module_put(t->me);
1043                 } else
1044                         ret = t ? PTR_ERR(t) : -ENOENT;
1045         }
1046         break;
1047
1048         case ARPT_SO_GET_ENTRIES: {
1049                 struct arpt_get_entries get;
1050
1051                 if (*len < sizeof(get)) {
1052                         duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1053                         ret = -EINVAL;
1054                 } else if (copy_from_user(&get, user, sizeof(get)) != 0) {
1055                         ret = -EFAULT;
1056                 } else if (*len != sizeof(struct arpt_get_entries) + get.size) {
1057                         duprintf("get_entries: %u != %Zu\n", *len,
1058                                  sizeof(struct arpt_get_entries) + get.size);
1059                         ret = -EINVAL;
1060                 } else
1061                         ret = get_entries(&get, user);
1062                 break;
1063         }
1064
1065         case ARPT_SO_GET_REVISION_TARGET: {
1066                 struct xt_get_revision rev;
1067
1068                 if (*len != sizeof(rev)) {
1069                         ret = -EINVAL;
1070                         break;
1071                 }
1072                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1073                         ret = -EFAULT;
1074                         break;
1075                 }
1076
1077                 try_then_request_module(xt_find_revision(NF_ARP, rev.name,
1078                                                          rev.revision, 1, &ret),
1079                                         "arpt_%s", rev.name);
1080                 break;
1081         }
1082
1083         default:
1084                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1085                 ret = -EINVAL;
1086         }
1087
1088         return ret;
1089 }
1090
1091 int arpt_register_table(struct arpt_table *table,
1092                         const struct arpt_replace *repl)
1093 {
1094         int ret;
1095         struct xt_table_info *newinfo;
1096         static struct xt_table_info bootstrap
1097                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1098         void *loc_cpu_entry;
1099
1100         newinfo = xt_alloc_table_info(repl->size);
1101         if (!newinfo) {
1102                 ret = -ENOMEM;
1103                 return ret;
1104         }
1105
1106         /* choose the copy on our node/cpu */
1107         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1108         memcpy(loc_cpu_entry, repl->entries, repl->size);
1109
1110         ret = translate_table(table->name, table->valid_hooks,
1111                               newinfo, loc_cpu_entry, repl->size,
1112                               repl->num_entries,
1113                               repl->hook_entry,
1114                               repl->underflow);
1115
1116         duprintf("arpt_register_table: translate table gives %d\n", ret);
1117         if (ret != 0) {
1118                 xt_free_table_info(newinfo);
1119                 return ret;
1120         }
1121
1122         ret = xt_register_table(table, &bootstrap, newinfo);
1123         if (ret != 0) {
1124                 xt_free_table_info(newinfo);
1125                 return ret;
1126         }
1127
1128         return 0;
1129 }
1130
1131 void arpt_unregister_table(struct arpt_table *table)
1132 {
1133         struct xt_table_info *private;
1134         void *loc_cpu_entry;
1135
1136         private = xt_unregister_table(table);
1137
1138         /* Decrease module usage counts and free resources */
1139         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1140         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1141                            cleanup_entry, NULL);
1142         xt_free_table_info(private);
1143 }
1144
1145 /* The built-in targets: standard (NULL) and error. */
1146 static struct arpt_target arpt_standard_target = {
1147         .name           = ARPT_STANDARD_TARGET,
1148         .targetsize     = sizeof(int),
1149         .family         = NF_ARP,
1150 };
1151
1152 static struct arpt_target arpt_error_target = {
1153         .name           = ARPT_ERROR_TARGET,
1154         .target         = arpt_error,
1155         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1156         .family         = NF_ARP,
1157 };
1158
1159 static struct nf_sockopt_ops arpt_sockopts = {
1160         .pf             = PF_INET,
1161         .set_optmin     = ARPT_BASE_CTL,
1162         .set_optmax     = ARPT_SO_SET_MAX+1,
1163         .set            = do_arpt_set_ctl,
1164         .get_optmin     = ARPT_BASE_CTL,
1165         .get_optmax     = ARPT_SO_GET_MAX+1,
1166         .get            = do_arpt_get_ctl,
1167 };
1168
1169 static int __init arp_tables_init(void)
1170 {
1171         int ret;
1172
1173         xt_proto_init(NF_ARP);
1174
1175         /* Noone else will be downing sem now, so we won't sleep */
1176         xt_register_target(&arpt_standard_target);
1177         xt_register_target(&arpt_error_target);
1178
1179         /* Register setsockopt */
1180         ret = nf_register_sockopt(&arpt_sockopts);
1181         if (ret < 0) {
1182                 duprintf("Unable to register sockopts.\n");
1183                 return ret;
1184         }
1185
1186         printk("arp_tables: (C) 2002 David S. Miller\n");
1187         return 0;
1188 }
1189
1190 static void __exit arp_tables_fini(void)
1191 {
1192         nf_unregister_sockopt(&arpt_sockopts);
1193         xt_proto_fini(NF_ARP);
1194 }
1195
1196 EXPORT_SYMBOL(arpt_register_table);
1197 EXPORT_SYMBOL(arpt_unregister_table);
1198 EXPORT_SYMBOL(arpt_do_table);
1199
1200 module_init(arp_tables_init);
1201 module_exit(arp_tables_fini);