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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 #include <linux/mutex.h>
  23 #include <linux/err.h>
  24 #include <net/compat.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter_arp/arp_tables.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  33 MODULE_DESCRIPTION("arptables core");
  34
  35 /*#define DEBUG_ARP_TABLES*/
  36 /*#define DEBUG_ARP_TABLES_USER*/
  37
  38 #ifdef DEBUG_ARP_TABLES
  39 #define dprintf(format, args...)  printk(format , ## args)
  40 #else
  41 #define dprintf(format, args...)
  42 #endif
  43
  44 #ifdef DEBUG_ARP_TABLES_USER
  45 #define duprintf(format, args...) printk(format , ## args)
  46 #else
  47 #define duprintf(format, args...)
  48 #endif
  49
  50 #ifdef CONFIG_NETFILTER_DEBUG
  51 #define ARP_NF_ASSERT(x)                                        \
  52 do {                                                            \
  53         if (!(x))                                               \
  54                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  55                        __func__, __FILE__, __LINE__);   \
  56 } while(0)
  57 #else
  58 #define ARP_NF_ASSERT(x)
  59 #endif
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       const 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 /*
  77  * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  78  * Some arches dont care, unrolling the loop is a win on them.
  79  */
  80 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  81 {
  82 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  83         unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  84 #else
  85         unsigned long ret = 0;
  86         int i;
  87
  88         for (i = 0; i < IFNAMSIZ; i++)
  89                 ret |= (_a[i] ^ _b[i]) & _mask[i];
  90 #endif
  91         return ret;
  92 }
  93
  94 /* Returns whether packet matches rule or not. */
  95 static inline int arp_packet_match(const struct arphdr *arphdr,
  96                                    struct net_device *dev,
  97                                    const char *indev,
  98                                    const char *outdev,
  99                                    const struct arpt_arp *arpinfo)
 100 {
 101         const char *arpptr = (char *)(arphdr + 1);
 102         const char *src_devaddr, *tgt_devaddr;
 103         __be32 src_ipaddr, tgt_ipaddr;
 104         long ret;
 105
 106 #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 107
 108         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 109                   ARPT_INV_ARPOP)) {
 110                 dprintf("ARP operation field mismatch.\n");
 111                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 112                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 113                 return 0;
 114         }
 115
 116         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 117                   ARPT_INV_ARPHRD)) {
 118                 dprintf("ARP hardware address format mismatch.\n");
 119                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 120                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 121                 return 0;
 122         }
 123
 124         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 125                   ARPT_INV_ARPPRO)) {
 126                 dprintf("ARP protocol address format mismatch.\n");
 127                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 128                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 129                 return 0;
 130         }
 131
 132         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 133                   ARPT_INV_ARPHLN)) {
 134                 dprintf("ARP hardware address length mismatch.\n");
 135                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 136                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 137                 return 0;
 138         }
 139
 140         src_devaddr = arpptr;
 141         arpptr += dev->addr_len;
 142         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 143         arpptr += sizeof(u32);
 144         tgt_devaddr = arpptr;
 145         arpptr += dev->addr_len;
 146         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 147
 148         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 149                   ARPT_INV_SRCDEVADDR) ||
 150             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 151                   ARPT_INV_TGTDEVADDR)) {
 152                 dprintf("Source or target device address mismatch.\n");
 153
 154                 return 0;
 155         }
 156
 157         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 158                   ARPT_INV_SRCIP) ||
 159             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 160                   ARPT_INV_TGTIP)) {
 161                 dprintf("Source or target IP address mismatch.\n");
 162
 163                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 164                         &src_ipaddr,
 165                         &arpinfo->smsk.s_addr,
 166                         &arpinfo->src.s_addr,
 167                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 168                 dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 169                         &tgt_ipaddr,
 170                         &arpinfo->tmsk.s_addr,
 171                         &arpinfo->tgt.s_addr,
 172                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 173                 return 0;
 174         }
 175
 176         /* Look for ifname matches.  */
 177         ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 178
 179         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 180                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 181                         indev, arpinfo->iniface,
 182                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 183                 return 0;
 184         }
 185
 186         ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 187
 188         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 189                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 190                         outdev, arpinfo->outiface,
 191                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 192                 return 0;
 193         }
 194
 195         return 1;
 196 #undef FWINV
 197 }
 198
 199 static inline int arp_checkentry(const struct arpt_arp *arp)
 200 {
 201         if (arp->flags & ~ARPT_F_MASK) {
 202                 duprintf("Unknown flag bits set: %08X\n",
 203                          arp->flags & ~ARPT_F_MASK);
 204                 return 0;
 205         }
 206         if (arp->invflags & ~ARPT_INV_MASK) {
 207                 duprintf("Unknown invflag bits set: %08X\n",
 208                          arp->invflags & ~ARPT_INV_MASK);
 209                 return 0;
 210         }
 211
 212         return 1;
 213 }
 214
 215 static unsigned int
 216 arpt_error(struct sk_buff *skb, const struct xt_target_param *par)
 217 {
 218         if (net_ratelimit())
 219                 printk("arp_tables: error: '%s'\n",
 220                        (const char *)par->targinfo);
 221
 222         return NF_DROP;
 223 }
 224
 225 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 226 {
 227         return (struct arpt_entry *)(base + offset);
 228 }
 229
 230 unsigned int arpt_do_table(struct sk_buff *skb,
 231                            unsigned int hook,
 232                            const struct net_device *in,
 233                            const struct net_device *out,
 234                            struct xt_table *table)
 235 {
 236         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 237         unsigned int verdict = NF_DROP;
 238         const struct arphdr *arp;
 239         bool hotdrop = false;
 240         struct arpt_entry *e, *back;
 241         const char *indev, *outdev;
 242         void *table_base;
 243         const struct xt_table_info *private;
 244         struct xt_target_param tgpar;
 245
 246         if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 247                 return NF_DROP;
 248
 249         indev = in ? in->name : nulldevname;
 250         outdev = out ? out->name : nulldevname;
 251
 252         rcu_read_lock();
 253         private = rcu_dereference(table->private);
 254         table_base = rcu_dereference(private->entries[smp_processor_id()]);
 255
 256         e = get_entry(table_base, private->hook_entry[hook]);
 257         back = get_entry(table_base, private->underflow[hook]);
 258
 259         tgpar.in      = in;
 260         tgpar.out     = out;
 261         tgpar.hooknum = hook;
 262         tgpar.family  = NFPROTO_ARP;
 263
 264         arp = arp_hdr(skb);
 265         do {
 266                 if (arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 267                         struct arpt_entry_target *t;
 268                         int hdr_len;
 269
 270                         hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 271                                 (2 * skb->dev->addr_len);
 272                         ADD_COUNTER(e->counters, hdr_len, 1);
 273
 274                         t = arpt_get_target(e);
 275
 276                         /* Standard target? */
 277                         if (!t->u.kernel.target->target) {
 278                                 int v;
 279
 280                                 v = ((struct arpt_standard_target *)t)->verdict;
 281                                 if (v < 0) {
 282                                         /* Pop from stack? */
 283                                         if (v != ARPT_RETURN) {
 284                                                 verdict = (unsigned)(-v) - 1;
 285                                                 break;
 286                                         }
 287                                         e = back;
 288                                         back = get_entry(table_base,
 289                                                          back->comefrom);
 290                                         continue;
 291                                 }
 292                                 if (table_base + v
 293                                     != (void *)e + e->next_offset) {
 294                                         /* Save old back ptr in next entry */
 295                                         struct arpt_entry *next
 296                                                 = (void *)e + e->next_offset;
 297                                         next->comefrom =
 298                                                 (void *)back - table_base;
 299
 300                                         /* set back pointer to next entry */
 301                                         back = next;
 302                                 }
 303
 304                                 e = get_entry(table_base, v);
 305                         } else {
 306                                 /* Targets which reenter must return
 307                                  * abs. verdicts
 308                                  */
 309                                 tgpar.target   = t->u.kernel.target;
 310                                 tgpar.targinfo = t->data;
 311                                 verdict = t->u.kernel.target->target(skb,
 312                                                                      &tgpar);
 313
 314                                 /* Target might have changed stuff. */
 315                                 arp = arp_hdr(skb);
 316
 317                                 if (verdict == ARPT_CONTINUE)
 318                                         e = (void *)e + e->next_offset;
 319                                 else
 320                                         /* Verdict */
 321                                         break;
 322                         }
 323                 } else {
 324                         e = (void *)e + e->next_offset;
 325                 }
 326         } while (!hotdrop);
 327
 328         rcu_read_unlock();
 329
 330         if (hotdrop)
 331                 return NF_DROP;
 332         else
 333                 return verdict;
 334 }
 335
 336 /* All zeroes == unconditional rule. */
 337 static inline int unconditional(const struct arpt_arp *arp)
 338 {
 339         unsigned int i;
 340
 341         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 342                 if (((__u32 *)arp)[i])
 343                         return 0;
 344
 345         return 1;
 346 }
 347
 348 /* Figures out from what hook each rule can be called: returns 0 if
 349  * there are loops.  Puts hook bitmask in comefrom.
 350  */
 351 static int mark_source_chains(struct xt_table_info *newinfo,
 352                               unsigned int valid_hooks, void *entry0)
 353 {
 354         unsigned int hook;
 355
 356         /* No recursion; use packet counter to save back ptrs (reset
 357          * to 0 as we leave), and comefrom to save source hook bitmask.
 358          */
 359         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 360                 unsigned int pos = newinfo->hook_entry[hook];
 361                 struct arpt_entry *e
 362                         = (struct arpt_entry *)(entry0 + pos);
 363
 364                 if (!(valid_hooks & (1 << hook)))
 365                         continue;
 366
 367                 /* Set initial back pointer. */
 368                 e->counters.pcnt = pos;
 369
 370                 for (;;) {
 371                         const struct arpt_standard_target *t
 372                                 = (void *)arpt_get_target(e);
 373                         int visited = e->comefrom & (1 << hook);
 374
 375                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 376                                 printk("arptables: loop hook %u pos %u %08X.\n",
 377                                        hook, pos, e->comefrom);
 378                                 return 0;
 379                         }
 380                         e->comefrom
 381                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 382
 383                         /* Unconditional return/END. */
 384                         if ((e->target_offset == sizeof(struct arpt_entry)
 385                             && (strcmp(t->target.u.user.name,
 386                                        ARPT_STANDARD_TARGET) == 0)
 387                             && t->verdict < 0
 388                             && unconditional(&e->arp)) || visited) {
 389                                 unsigned int oldpos, size;
 390
 391                                 if ((strcmp(t->target.u.user.name,
 392                                             ARPT_STANDARD_TARGET) == 0) &&
 393                                     t->verdict < -NF_MAX_VERDICT - 1) {
 394                                         duprintf("mark_source_chains: bad "
 395                                                 "negative verdict (%i)\n",
 396                                                                 t->verdict);
 397                                         return 0;
 398                                 }
 399
 400                                 /* Return: backtrack through the last
 401                                  * big jump.
 402                                  */
 403                                 do {
 404                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 405                                         oldpos = pos;
 406                                         pos = e->counters.pcnt;
 407                                         e->counters.pcnt = 0;
 408
 409                                         /* We're at the start. */
 410                                         if (pos == oldpos)
 411                                                 goto next;
 412
 413                                         e = (struct arpt_entry *)
 414                                                 (entry0 + pos);
 415                                 } while (oldpos == pos + e->next_offset);
 416
 417                                 /* Move along one */
 418                                 size = e->next_offset;
 419                                 e = (struct arpt_entry *)
 420                                         (entry0 + pos + size);
 421                                 e->counters.pcnt = pos;
 422                                 pos += size;
 423                         } else {
 424                                 int newpos = t->verdict;
 425
 426                                 if (strcmp(t->target.u.user.name,
 427                                            ARPT_STANDARD_TARGET) == 0
 428                                     && newpos >= 0) {
 429                                         if (newpos > newinfo->size -
 430                                                 sizeof(struct arpt_entry)) {
 431                                                 duprintf("mark_source_chains: "
 432                                                         "bad verdict (%i)\n",
 433                                                                 newpos);
 434                                                 return 0;
 435                                         }
 436
 437                                         /* This a jump; chase it. */
 438                                         duprintf("Jump rule %u -> %u\n",
 439                                                  pos, newpos);
 440                                 } else {
 441                                         /* ... this is a fallthru */
 442                                         newpos = pos + e->next_offset;
 443                                 }
 444                                 e = (struct arpt_entry *)
 445                                         (entry0 + newpos);
 446                                 e->counters.pcnt = pos;
 447                                 pos = newpos;
 448                         }
 449                 }
 450                 next:
 451                 duprintf("Finished chain %u\n", hook);
 452         }
 453         return 1;
 454 }
 455
 456 static inline int check_entry(struct arpt_entry *e, const char *name)
 457 {
 458         const struct arpt_entry_target *t;
 459
 460         if (!arp_checkentry(&e->arp)) {
 461                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 462                 return -EINVAL;
 463         }
 464
 465         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 466                 return -EINVAL;
 467
 468         t = arpt_get_target(e);
 469         if (e->target_offset + t->u.target_size > e->next_offset)
 470                 return -EINVAL;
 471
 472         return 0;
 473 }
 474
 475 static inline int check_target(struct arpt_entry *e, const char *name)
 476 {
 477         struct arpt_entry_target *t = arpt_get_target(e);
 478         int ret;
 479         struct xt_tgchk_param par = {
 480                 .table     = name,
 481                 .entryinfo = e,
 482                 .target    = t->u.kernel.target,
 483                 .targinfo  = t->data,
 484                 .hook_mask = e->comefrom,
 485                 .family    = NFPROTO_ARP,
 486         };
 487
 488         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 489         if (ret < 0) {
 490                 duprintf("arp_tables: check failed for `%s'.\n",
 491                          t->u.kernel.target->name);
 492                 return ret;
 493         }
 494         return 0;
 495 }
 496
 497 static inline int
 498 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 499                  unsigned int *i)
 500 {
 501         struct arpt_entry_target *t;
 502         struct xt_target *target;
 503         int ret;
 504
 505         ret = check_entry(e, name);
 506         if (ret)
 507                 return ret;
 508
 509         t = arpt_get_target(e);
 510         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 511                                                         t->u.user.name,
 512                                                         t->u.user.revision),
 513                                          "arpt_%s", t->u.user.name);
 514         if (IS_ERR(target) || !target) {
 515                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 516                 ret = target ? PTR_ERR(target) : -ENOENT;
 517                 goto out;
 518         }
 519         t->u.kernel.target = target;
 520
 521         ret = check_target(e, name);
 522         if (ret)
 523                 goto err;
 524
 525         (*i)++;
 526         return 0;
 527 err:
 528         module_put(t->u.kernel.target->me);
 529 out:
 530         return ret;
 531 }
 532
 533 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 534                                              struct xt_table_info *newinfo,
 535                                              unsigned char *base,
 536                                              unsigned char *limit,
 537                                              const unsigned int *hook_entries,
 538                                              const unsigned int *underflows,
 539                                              unsigned int *i)
 540 {
 541         unsigned int h;
 542
 543         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 544             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 545                 duprintf("Bad offset %p\n", e);
 546                 return -EINVAL;
 547         }
 548
 549         if (e->next_offset
 550             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 551                 duprintf("checking: element %p size %u\n",
 552                          e, e->next_offset);
 553                 return -EINVAL;
 554         }
 555
 556         /* Check hooks & underflows */
 557         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 558                 if ((unsigned char *)e - base == hook_entries[h])
 559                         newinfo->hook_entry[h] = hook_entries[h];
 560                 if ((unsigned char *)e - base == underflows[h])
 561                         newinfo->underflow[h] = underflows[h];
 562         }
 563
 564         /* FIXME: underflows must be unconditional, standard verdicts
 565            < 0 (not ARPT_RETURN). --RR */
 566
 567         /* Clear counters and comefrom */
 568         e->counters = ((struct xt_counters) { 0, 0 });
 569         e->comefrom = 0;
 570
 571         (*i)++;
 572         return 0;
 573 }
 574
 575 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 576 {
 577         struct xt_tgdtor_param par;
 578         struct arpt_entry_target *t;
 579
 580         if (i && (*i)-- == 0)
 581                 return 1;
 582
 583         t = arpt_get_target(e);
 584         par.target   = t->u.kernel.target;
 585         par.targinfo = t->data;
 586         par.family   = NFPROTO_ARP;
 587         if (par.target->destroy != NULL)
 588                 par.target->destroy(&par);
 589         module_put(par.target->me);
 590         return 0;
 591 }
 592
 593 /* Checks and translates the user-supplied table segment (held in
 594  * newinfo).
 595  */
 596 static int translate_table(const char *name,
 597                            unsigned int valid_hooks,
 598                            struct xt_table_info *newinfo,
 599                            void *entry0,
 600                            unsigned int size,
 601                            unsigned int number,
 602                            const unsigned int *hook_entries,
 603                            const unsigned int *underflows)
 604 {
 605         unsigned int i;
 606         int ret;
 607
 608         newinfo->size = size;
 609         newinfo->number = number;
 610
 611         /* Init all hooks to impossible value. */
 612         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 613                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 614                 newinfo->underflow[i] = 0xFFFFFFFF;
 615         }
 616
 617         duprintf("translate_table: size %u\n", newinfo->size);
 618         i = 0;
 619
 620         /* Walk through entries, checking offsets. */
 621         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 622                                  check_entry_size_and_hooks,
 623                                  newinfo,
 624                                  entry0,
 625                                  entry0 + size,
 626                                  hook_entries, underflows, &i);
 627         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 628         if (ret != 0)
 629                 return ret;
 630
 631         if (i != number) {
 632                 duprintf("translate_table: %u not %u entries\n",
 633                          i, number);
 634                 return -EINVAL;
 635         }
 636
 637         /* Check hooks all assigned */
 638         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 639                 /* Only hooks which are valid */
 640                 if (!(valid_hooks & (1 << i)))
 641                         continue;
 642                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 643                         duprintf("Invalid hook entry %u %u\n",
 644                                  i, hook_entries[i]);
 645                         return -EINVAL;
 646                 }
 647                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 648                         duprintf("Invalid underflow %u %u\n",
 649                                  i, underflows[i]);
 650                         return -EINVAL;
 651                 }
 652         }
 653
 654         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 655                 duprintf("Looping hook\n");
 656                 return -ELOOP;
 657         }
 658
 659         /* Finally, each sanity check must pass */
 660         i = 0;
 661         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 662                                  find_check_entry, name, size, &i);
 663
 664         if (ret != 0) {
 665                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 666                                 cleanup_entry, &i);
 667                 return ret;
 668         }
 669
 670         /* And one copy for every other CPU */
 671         for_each_possible_cpu(i) {
 672                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 673                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 674         }
 675
 676         return ret;
 677 }
 678
 679 /* Gets counters. */
 680 static inline int add_entry_to_counter(const struct arpt_entry *e,
 681                                        struct xt_counters total[],
 682                                        unsigned int *i)
 683 {
 684         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 685
 686         (*i)++;
 687         return 0;
 688 }
 689
 690 static inline int set_entry_to_counter(const struct arpt_entry *e,
 691                                        struct xt_counters total[],
 692                                        unsigned int *i)
 693 {
 694         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 695
 696         (*i)++;
 697         return 0;
 698 }
 699
 700 static void get_counters(const struct xt_table_info *t,
 701                          struct xt_counters counters[])
 702 {
 703         unsigned int cpu;
 704         unsigned int i;
 705         unsigned int curcpu;
 706
 707         /* Instead of clearing (by a previous call to memset())
 708          * the counters and using adds, we set the counters
 709          * with data used by 'current' CPU
 710          * We dont care about preemption here.
 711          */
 712         curcpu = raw_smp_processor_id();
 713
 714         i = 0;
 715         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 716                            t->size,
 717                            set_entry_to_counter,
 718                            counters,
 719                            &i);
 720
 721         for_each_possible_cpu(cpu) {
 722                 if (cpu == curcpu)
 723                         continue;
 724                 i = 0;
 725                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 726                                    t->size,
 727                                    add_entry_to_counter,
 728                                    counters,
 729                                    &i);
 730         }
 731 }
 732
 733
 734 /* We're lazy, and add to the first CPU; overflow works its fey magic
 735  * and everything is OK. */
 736 static int
 737 add_counter_to_entry(struct arpt_entry *e,
 738                      const struct xt_counters addme[],
 739                      unsigned int *i)
 740 {
 741         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
 742
 743         (*i)++;
 744         return 0;
 745 }
 746
 747 /* Take values from counters and add them back onto the current cpu */
 748 static void put_counters(struct xt_table_info *t,
 749                          const struct xt_counters counters[])
 750 {
 751         unsigned int i, cpu;
 752
 753         local_bh_disable();
 754         cpu = smp_processor_id();
 755         i = 0;
 756         ARPT_ENTRY_ITERATE(t->entries[cpu],
 757                           t->size,
 758                           add_counter_to_entry,
 759                           counters,
 760                           &i);
 761         local_bh_enable();
 762 }
 763
 764 static inline int
 765 zero_entry_counter(struct arpt_entry *e, void *arg)
 766 {
 767         e->counters.bcnt = 0;
 768         e->counters.pcnt = 0;
 769         return 0;
 770 }
 771
 772 static void
 773 clone_counters(struct xt_table_info *newinfo, const struct xt_table_info *info)
 774 {
 775         unsigned int cpu;
 776         const void *loc_cpu_entry = info->entries[raw_smp_processor_id()];
 777
 778         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 779         for_each_possible_cpu(cpu) {
 780                 memcpy(newinfo->entries[cpu], loc_cpu_entry, info->size);
 781                 ARPT_ENTRY_ITERATE(newinfo->entries[cpu], newinfo->size,
 782                                   zero_entry_counter, NULL);
 783         }
 784 }
 785
 786 static struct xt_counters *alloc_counters(struct xt_table *table)
 787 {
 788         unsigned int countersize;
 789         struct xt_counters *counters;
 790         struct xt_table_info *private = table->private;
 791         struct xt_table_info *info;
 792
 793         /* We need atomic snapshot of counters: rest doesn't change
 794          * (other than comefrom, which userspace doesn't care
 795          * about).
 796          */
 797         countersize = sizeof(struct xt_counters) * private->number;
 798         counters = vmalloc_node(countersize, numa_node_id());
 799
 800         if (counters == NULL)
 801                 goto nomem;
 802
 803         info = xt_alloc_table_info(private->size);
 804         if (!info)
 805                 goto free_counters;
 806
 807         clone_counters(info, private);
 808
 809         mutex_lock(&table->lock);
 810         xt_table_entry_swap_rcu(private, info);
 811         synchronize_net();      /* Wait until smoke has cleared */
 812
 813         get_counters(info, counters);
 814         put_counters(private, counters);
 815         mutex_unlock(&table->lock);
 816
 817         xt_free_table_info(info);
 818
 819         return counters;
 820
 821  free_counters:
 822         vfree(counters);
 823  nomem:
 824         return ERR_PTR(-ENOMEM);
 825 }
 826
 827 static int copy_entries_to_user(unsigned int total_size,
 828                                 struct xt_table *table,
 829                                 void __user *userptr)
 830 {
 831         unsigned int off, num;
 832         struct arpt_entry *e;
 833         struct xt_counters *counters;
 834         struct xt_table_info *private = table->private;
 835         int ret = 0;
 836         void *loc_cpu_entry;
 837
 838         counters = alloc_counters(table);
 839         if (IS_ERR(counters))
 840                 return PTR_ERR(counters);
 841
 842         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 843         /* ... then copy entire thing ... */
 844         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 845                 ret = -EFAULT;
 846                 goto free_counters;
 847         }
 848
 849         /* FIXME: use iterator macros --RR */
 850         /* ... then go back and fix counters and names */
 851         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 852                 struct arpt_entry_target *t;
 853
 854                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 855                 if (copy_to_user(userptr + off
 856                                  + offsetof(struct arpt_entry, counters),
 857                                  &counters[num],
 858                                  sizeof(counters[num])) != 0) {
 859                         ret = -EFAULT;
 860                         goto free_counters;
 861                 }
 862
 863                 t = arpt_get_target(e);
 864                 if (copy_to_user(userptr + off + e->target_offset
 865                                  + offsetof(struct arpt_entry_target,
 866                                             u.user.name),
 867                                  t->u.kernel.target->name,
 868                                  strlen(t->u.kernel.target->name)+1) != 0) {
 869                         ret = -EFAULT;
 870                         goto free_counters;
 871                 }
 872         }
 873
 874  free_counters:
 875         vfree(counters);
 876         return ret;
 877 }
 878
 879 #ifdef CONFIG_COMPAT
 880 static void compat_standard_from_user(void *dst, void *src)
 881 {
 882         int v = *(compat_int_t *)src;
 883
 884         if (v > 0)
 885                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 886         memcpy(dst, &v, sizeof(v));
 887 }
 888
 889 static int compat_standard_to_user(void __user *dst, void *src)
 890 {
 891         compat_int_t cv = *(int *)src;
 892
 893         if (cv > 0)
 894                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 895         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 896 }
 897
 898 static int compat_calc_entry(struct arpt_entry *e,
 899                              const struct xt_table_info *info,
 900                              void *base, struct xt_table_info *newinfo)
 901 {
 902         struct arpt_entry_target *t;
 903         unsigned int entry_offset;
 904         int off, i, ret;
 905
 906         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 907         entry_offset = (void *)e - base;
 908
 909         t = arpt_get_target(e);
 910         off += xt_compat_target_offset(t->u.kernel.target);
 911         newinfo->size -= off;
 912         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 913         if (ret)
 914                 return ret;
 915
 916         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 917                 if (info->hook_entry[i] &&
 918                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 919                         newinfo->hook_entry[i] -= off;
 920                 if (info->underflow[i] &&
 921                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 922                         newinfo->underflow[i] -= off;
 923         }
 924         return 0;
 925 }
 926
 927 static int compat_table_info(const struct xt_table_info *info,
 928                              struct xt_table_info *newinfo)
 929 {
 930         void *loc_cpu_entry;
 931
 932         if (!newinfo || !info)
 933                 return -EINVAL;
 934
 935         /* we dont care about newinfo->entries[] */
 936         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 937         newinfo->initial_entries = 0;
 938         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 939         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 940                                   compat_calc_entry, info, loc_cpu_entry,
 941                                   newinfo);
 942 }
 943 #endif
 944
 945 static int get_info(struct net *net, void __user *user, int *len, int compat)
 946 {
 947         char name[ARPT_TABLE_MAXNAMELEN];
 948         struct xt_table *t;
 949         int ret;
 950
 951         if (*len != sizeof(struct arpt_getinfo)) {
 952                 duprintf("length %u != %Zu\n", *len,
 953                          sizeof(struct arpt_getinfo));
 954                 return -EINVAL;
 955         }
 956
 957         if (copy_from_user(name, user, sizeof(name)) != 0)
 958                 return -EFAULT;
 959
 960         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 961 #ifdef CONFIG_COMPAT
 962         if (compat)
 963                 xt_compat_lock(NFPROTO_ARP);
 964 #endif
 965         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 966                                     "arptable_%s", name);
 967         if (t && !IS_ERR(t)) {
 968                 struct arpt_getinfo info;
 969                 const struct xt_table_info *private = t->private;
 970
 971 #ifdef CONFIG_COMPAT
 972                 if (compat) {
 973                         struct xt_table_info tmp;
 974                         ret = compat_table_info(private, &tmp);
 975                         xt_compat_flush_offsets(NFPROTO_ARP);
 976                         private = &tmp;
 977                 }
 978 #endif
 979                 info.valid_hooks = t->valid_hooks;
 980                 memcpy(info.hook_entry, private->hook_entry,
 981                        sizeof(info.hook_entry));
 982                 memcpy(info.underflow, private->underflow,
 983                        sizeof(info.underflow));
 984                 info.num_entries = private->number;
 985                 info.size = private->size;
 986                 strcpy(info.name, name);
 987
 988                 if (copy_to_user(user, &info, *len) != 0)
 989                         ret = -EFAULT;
 990                 else
 991                         ret = 0;
 992                 xt_table_unlock(t);
 993                 module_put(t->me);
 994         } else
 995                 ret = t ? PTR_ERR(t) : -ENOENT;
 996 #ifdef CONFIG_COMPAT
 997         if (compat)
 998                 xt_compat_unlock(NFPROTO_ARP);
 999 #endif
1000         return ret;
1001 }
1002
1003 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
1004                        int *len)
1005 {
1006         int ret;
1007         struct arpt_get_entries get;
1008         struct xt_table *t;
1009
1010         if (*len < sizeof(get)) {
1011                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1012                 return -EINVAL;
1013         }
1014         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1015                 return -EFAULT;
1016         if (*len != sizeof(struct arpt_get_entries) + get.size) {
1017                 duprintf("get_entries: %u != %Zu\n", *len,
1018                          sizeof(struct arpt_get_entries) + get.size);
1019                 return -EINVAL;
1020         }
1021
1022         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1023         if (t && !IS_ERR(t)) {
1024                 const struct xt_table_info *private = t->private;
1025
1026                 duprintf("t->private->number = %u\n",
1027                          private->number);
1028                 if (get.size == private->size)
1029                         ret = copy_entries_to_user(private->size,
1030                                                    t, uptr->entrytable);
1031                 else {
1032                         duprintf("get_entries: I've got %u not %u!\n",
1033                                  private->size, get.size);
1034                         ret = -EAGAIN;
1035                 }
1036                 module_put(t->me);
1037                 xt_table_unlock(t);
1038         } else
1039                 ret = t ? PTR_ERR(t) : -ENOENT;
1040
1041         return ret;
1042 }
1043
1044 static int __do_replace(struct net *net, const char *name,
1045                         unsigned int valid_hooks,
1046                         struct xt_table_info *newinfo,
1047                         unsigned int num_counters,
1048                         void __user *counters_ptr)
1049 {
1050         int ret;
1051         struct xt_table *t;
1052         struct xt_table_info *oldinfo;
1053         struct xt_counters *counters;
1054         void *loc_cpu_old_entry;
1055
1056         ret = 0;
1057         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
1058                                 numa_node_id());
1059         if (!counters) {
1060                 ret = -ENOMEM;
1061                 goto out;
1062         }
1063
1064         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1065                                     "arptable_%s", name);
1066         if (!t || IS_ERR(t)) {
1067                 ret = t ? PTR_ERR(t) : -ENOENT;
1068                 goto free_newinfo_counters_untrans;
1069         }
1070
1071         /* You lied! */
1072         if (valid_hooks != t->valid_hooks) {
1073                 duprintf("Valid hook crap: %08X vs %08X\n",
1074                          valid_hooks, t->valid_hooks);
1075                 ret = -EINVAL;
1076                 goto put_module;
1077         }
1078
1079         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1080         if (!oldinfo)
1081                 goto put_module;
1082
1083         /* Update module usage count based on number of rules */
1084         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1085                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1086         if ((oldinfo->number > oldinfo->initial_entries) ||
1087             (newinfo->number <= oldinfo->initial_entries))
1088                 module_put(t->me);
1089         if ((oldinfo->number > oldinfo->initial_entries) &&
1090             (newinfo->number <= oldinfo->initial_entries))
1091                 module_put(t->me);
1092
1093         /* Get the old counters. */
1094         get_counters(oldinfo, counters);
1095         /* Decrease module usage counts and free resource */
1096         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1097         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1098                            NULL);
1099
1100         xt_free_table_info(oldinfo);
1101         if (copy_to_user(counters_ptr, counters,
1102                          sizeof(struct xt_counters) * num_counters) != 0)
1103                 ret = -EFAULT;
1104         vfree(counters);
1105         xt_table_unlock(t);
1106         return ret;
1107
1108  put_module:
1109         module_put(t->me);
1110         xt_table_unlock(t);
1111  free_newinfo_counters_untrans:
1112         vfree(counters);
1113  out:
1114         return ret;
1115 }
1116
1117 static int do_replace(struct net *net, void __user *user, unsigned int len)
1118 {
1119         int ret;
1120         struct arpt_replace tmp;
1121         struct xt_table_info *newinfo;
1122         void *loc_cpu_entry;
1123
1124         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1125                 return -EFAULT;
1126
1127         /* overflow check */
1128         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1129                 return -ENOMEM;
1130
1131         newinfo = xt_alloc_table_info(tmp.size);
1132         if (!newinfo)
1133                 return -ENOMEM;
1134
1135         /* choose the copy that is on our node/cpu */
1136         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1137         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1138                            tmp.size) != 0) {
1139                 ret = -EFAULT;
1140                 goto free_newinfo;
1141         }
1142
1143         ret = translate_table(tmp.name, tmp.valid_hooks,
1144                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1145                               tmp.hook_entry, tmp.underflow);
1146         if (ret != 0)
1147                 goto free_newinfo;
1148
1149         duprintf("arp_tables: Translated table\n");
1150
1151         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1152                            tmp.num_counters, tmp.counters);
1153         if (ret)
1154                 goto free_newinfo_untrans;
1155         return 0;
1156
1157  free_newinfo_untrans:
1158         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1159  free_newinfo:
1160         xt_free_table_info(newinfo);
1161         return ret;
1162 }
1163
1164 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1165                            int compat)
1166 {
1167         unsigned int i;
1168         struct xt_counters_info tmp;
1169         struct xt_counters *paddc;
1170         unsigned int num_counters;
1171         const char *name;
1172         int size;
1173         void *ptmp;
1174         struct xt_table *t;
1175         const struct xt_table_info *private;
1176         int ret = 0;
1177         void *loc_cpu_entry;
1178 #ifdef CONFIG_COMPAT
1179         struct compat_xt_counters_info compat_tmp;
1180
1181         if (compat) {
1182                 ptmp = &compat_tmp;
1183                 size = sizeof(struct compat_xt_counters_info);
1184         } else
1185 #endif
1186         {
1187                 ptmp = &tmp;
1188                 size = sizeof(struct xt_counters_info);
1189         }
1190
1191         if (copy_from_user(ptmp, user, size) != 0)
1192                 return -EFAULT;
1193
1194 #ifdef CONFIG_COMPAT
1195         if (compat) {
1196                 num_counters = compat_tmp.num_counters;
1197                 name = compat_tmp.name;
1198         } else
1199 #endif
1200         {
1201                 num_counters = tmp.num_counters;
1202                 name = tmp.name;
1203         }
1204
1205         if (len != size + num_counters * sizeof(struct xt_counters))
1206                 return -EINVAL;
1207
1208         paddc = vmalloc_node(len - size, numa_node_id());
1209         if (!paddc)
1210                 return -ENOMEM;
1211
1212         if (copy_from_user(paddc, user + size, len - size) != 0) {
1213                 ret = -EFAULT;
1214                 goto free;
1215         }
1216
1217         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1218         if (!t || IS_ERR(t)) {
1219                 ret = t ? PTR_ERR(t) : -ENOENT;
1220                 goto free;
1221         }
1222
1223         mutex_lock(&t->lock);
1224         private = t->private;
1225         if (private->number != num_counters) {
1226                 ret = -EINVAL;
1227                 goto unlock_up_free;
1228         }
1229
1230         preempt_disable();
1231         i = 0;
1232         /* Choose the copy that is on our node */
1233         loc_cpu_entry = private->entries[smp_processor_id()];
1234         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1235                            private->size,
1236                            add_counter_to_entry,
1237                            paddc,
1238                            &i);
1239         preempt_enable();
1240  unlock_up_free:
1241         mutex_unlock(&t->lock);
1242
1243         xt_table_unlock(t);
1244         module_put(t->me);
1245  free:
1246         vfree(paddc);
1247
1248         return ret;
1249 }
1250
1251 #ifdef CONFIG_COMPAT
1252 static inline int
1253 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1254 {
1255         struct arpt_entry_target *t;
1256
1257         if (i && (*i)-- == 0)
1258                 return 1;
1259
1260         t = compat_arpt_get_target(e);
1261         module_put(t->u.kernel.target->me);
1262         return 0;
1263 }
1264
1265 static inline int
1266 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1267                                   struct xt_table_info *newinfo,
1268                                   unsigned int *size,
1269                                   unsigned char *base,
1270                                   unsigned char *limit,
1271                                   unsigned int *hook_entries,
1272                                   unsigned int *underflows,
1273                                   unsigned int *i,
1274                                   const char *name)
1275 {
1276         struct arpt_entry_target *t;
1277         struct xt_target *target;
1278         unsigned int entry_offset;
1279         int ret, off, h;
1280
1281         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1282         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1283             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1284                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1285                 return -EINVAL;
1286         }
1287
1288         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1289                              sizeof(struct compat_xt_entry_target)) {
1290                 duprintf("checking: element %p size %u\n",
1291                          e, e->next_offset);
1292                 return -EINVAL;
1293         }
1294
1295         /* For purposes of check_entry casting the compat entry is fine */
1296         ret = check_entry((struct arpt_entry *)e, name);
1297         if (ret)
1298                 return ret;
1299
1300         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1301         entry_offset = (void *)e - (void *)base;
1302
1303         t = compat_arpt_get_target(e);
1304         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1305                                                         t->u.user.name,
1306                                                         t->u.user.revision),
1307                                          "arpt_%s", t->u.user.name);
1308         if (IS_ERR(target) || !target) {
1309                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1310                          t->u.user.name);
1311                 ret = target ? PTR_ERR(target) : -ENOENT;
1312                 goto out;
1313         }
1314         t->u.kernel.target = target;
1315
1316         off += xt_compat_target_offset(target);
1317         *size += off;
1318         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1319         if (ret)
1320                 goto release_target;
1321
1322         /* Check hooks & underflows */
1323         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1324                 if ((unsigned char *)e - base == hook_entries[h])
1325                         newinfo->hook_entry[h] = hook_entries[h];
1326                 if ((unsigned char *)e - base == underflows[h])
1327                         newinfo->underflow[h] = underflows[h];
1328         }
1329
1330         /* Clear counters and comefrom */
1331         memset(&e->counters, 0, sizeof(e->counters));
1332         e->comefrom = 0;
1333
1334         (*i)++;
1335         return 0;
1336
1337 release_target:
1338         module_put(t->u.kernel.target->me);
1339 out:
1340         return ret;
1341 }
1342
1343 static int
1344 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1345                             unsigned int *size, const char *name,
1346                             struct xt_table_info *newinfo, unsigned char *base)
1347 {
1348         struct arpt_entry_target *t;
1349         struct xt_target *target;
1350         struct arpt_entry *de;
1351         unsigned int origsize;
1352         int ret, h;
1353
1354         ret = 0;
1355         origsize = *size;
1356         de = (struct arpt_entry *)*dstptr;
1357         memcpy(de, e, sizeof(struct arpt_entry));
1358         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1359
1360         *dstptr += sizeof(struct arpt_entry);
1361         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1362
1363         de->target_offset = e->target_offset - (origsize - *size);
1364         t = compat_arpt_get_target(e);
1365         target = t->u.kernel.target;
1366         xt_compat_target_from_user(t, dstptr, size);
1367
1368         de->next_offset = e->next_offset - (origsize - *size);
1369         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1370                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1371                         newinfo->hook_entry[h] -= origsize - *size;
1372                 if ((unsigned char *)de - base < newinfo->underflow[h])
1373                         newinfo->underflow[h] -= origsize - *size;
1374         }
1375         return ret;
1376 }
1377
1378 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1379                                      unsigned int *i)
1380 {
1381         int ret;
1382
1383         ret = check_target(e, name);
1384         if (ret)
1385                 return ret;
1386
1387         (*i)++;
1388         return 0;
1389 }
1390
1391 static int translate_compat_table(const char *name,
1392                                   unsigned int valid_hooks,
1393                                   struct xt_table_info **pinfo,
1394                                   void **pentry0,
1395                                   unsigned int total_size,
1396                                   unsigned int number,
1397                                   unsigned int *hook_entries,
1398                                   unsigned int *underflows)
1399 {
1400         unsigned int i, j;
1401         struct xt_table_info *newinfo, *info;
1402         void *pos, *entry0, *entry1;
1403         unsigned int size;
1404         int ret;
1405
1406         info = *pinfo;
1407         entry0 = *pentry0;
1408         size = total_size;
1409         info->number = number;
1410
1411         /* Init all hooks to impossible value. */
1412         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1413                 info->hook_entry[i] = 0xFFFFFFFF;
1414                 info->underflow[i] = 0xFFFFFFFF;
1415         }
1416
1417         duprintf("translate_compat_table: size %u\n", info->size);
1418         j = 0;
1419         xt_compat_lock(NFPROTO_ARP);
1420         /* Walk through entries, checking offsets. */
1421         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1422                                         check_compat_entry_size_and_hooks,
1423                                         info, &size, entry0,
1424                                         entry0 + total_size,
1425                                         hook_entries, underflows, &j, name);
1426         if (ret != 0)
1427                 goto out_unlock;
1428
1429         ret = -EINVAL;
1430         if (j != number) {
1431                 duprintf("translate_compat_table: %u not %u entries\n",
1432                          j, number);
1433                 goto out_unlock;
1434         }
1435
1436         /* Check hooks all assigned */
1437         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1438                 /* Only hooks which are valid */
1439                 if (!(valid_hooks & (1 << i)))
1440                         continue;
1441                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1442                         duprintf("Invalid hook entry %u %u\n",
1443                                  i, hook_entries[i]);
1444                         goto out_unlock;
1445                 }
1446                 if (info->underflow[i] == 0xFFFFFFFF) {
1447                         duprintf("Invalid underflow %u %u\n",
1448                                  i, underflows[i]);
1449                         goto out_unlock;
1450                 }
1451         }
1452
1453         ret = -ENOMEM;
1454         newinfo = xt_alloc_table_info(size);
1455         if (!newinfo)
1456                 goto out_unlock;
1457
1458         newinfo->number = number;
1459         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1460                 newinfo->hook_entry[i] = info->hook_entry[i];
1461                 newinfo->underflow[i] = info->underflow[i];
1462         }
1463         entry1 = newinfo->entries[raw_smp_processor_id()];
1464         pos = entry1;
1465         size = total_size;
1466         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1467                                         compat_copy_entry_from_user,
1468                                         &pos, &size, name, newinfo, entry1);
1469         xt_compat_flush_offsets(NFPROTO_ARP);
1470         xt_compat_unlock(NFPROTO_ARP);
1471         if (ret)
1472                 goto free_newinfo;
1473
1474         ret = -ELOOP;
1475         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1476                 goto free_newinfo;
1477
1478         i = 0;
1479         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1480                                  name, &i);
1481         if (ret) {
1482                 j -= i;
1483                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1484                                                    compat_release_entry, &j);
1485                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1486                 xt_free_table_info(newinfo);
1487                 return ret;
1488         }
1489
1490         /* And one copy for every other CPU */
1491         for_each_possible_cpu(i)
1492                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1493                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1494
1495         *pinfo = newinfo;
1496         *pentry0 = entry1;
1497         xt_free_table_info(info);
1498         return 0;
1499
1500 free_newinfo:
1501         xt_free_table_info(newinfo);
1502 out:
1503         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1504         return ret;
1505 out_unlock:
1506         xt_compat_flush_offsets(NFPROTO_ARP);
1507         xt_compat_unlock(NFPROTO_ARP);
1508         goto out;
1509 }
1510
1511 struct compat_arpt_replace {
1512         char                            name[ARPT_TABLE_MAXNAMELEN];
1513         u32                             valid_hooks;
1514         u32                             num_entries;
1515         u32                             size;
1516         u32                             hook_entry[NF_ARP_NUMHOOKS];
1517         u32                             underflow[NF_ARP_NUMHOOKS];
1518         u32                             num_counters;
1519         compat_uptr_t                   counters;
1520         struct compat_arpt_entry        entries[0];
1521 };
1522
1523 static int compat_do_replace(struct net *net, void __user *user,
1524                              unsigned int len)
1525 {
1526         int ret;
1527         struct compat_arpt_replace tmp;
1528         struct xt_table_info *newinfo;
1529         void *loc_cpu_entry;
1530
1531         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1532                 return -EFAULT;
1533
1534         /* overflow check */
1535         if (tmp.size >= INT_MAX / num_possible_cpus())
1536                 return -ENOMEM;
1537         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1538                 return -ENOMEM;
1539
1540         newinfo = xt_alloc_table_info(tmp.size);
1541         if (!newinfo)
1542                 return -ENOMEM;
1543
1544         /* choose the copy that is on our node/cpu */
1545         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1546         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1547                 ret = -EFAULT;
1548                 goto free_newinfo;
1549         }
1550
1551         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1552                                      &newinfo, &loc_cpu_entry, tmp.size,
1553                                      tmp.num_entries, tmp.hook_entry,
1554                                      tmp.underflow);
1555         if (ret != 0)
1556                 goto free_newinfo;
1557
1558         duprintf("compat_do_replace: Translated table\n");
1559
1560         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1561                            tmp.num_counters, compat_ptr(tmp.counters));
1562         if (ret)
1563                 goto free_newinfo_untrans;
1564         return 0;
1565
1566  free_newinfo_untrans:
1567         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1568  free_newinfo:
1569         xt_free_table_info(newinfo);
1570         return ret;
1571 }
1572
1573 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1574                                   unsigned int len)
1575 {
1576         int ret;
1577
1578         if (!capable(CAP_NET_ADMIN))
1579                 return -EPERM;
1580
1581         switch (cmd) {
1582         case ARPT_SO_SET_REPLACE:
1583                 ret = compat_do_replace(sock_net(sk), user, len);
1584                 break;
1585
1586         case ARPT_SO_SET_ADD_COUNTERS:
1587                 ret = do_add_counters(sock_net(sk), user, len, 1);
1588                 break;
1589
1590         default:
1591                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1592                 ret = -EINVAL;
1593         }
1594
1595         return ret;
1596 }
1597
1598 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1599                                      compat_uint_t *size,
1600                                      struct xt_counters *counters,
1601                                      unsigned int *i)
1602 {
1603         struct arpt_entry_target *t;
1604         struct compat_arpt_entry __user *ce;
1605         u_int16_t target_offset, next_offset;
1606         compat_uint_t origsize;
1607         int ret;
1608
1609         ret = -EFAULT;
1610         origsize = *size;
1611         ce = (struct compat_arpt_entry __user *)*dstptr;
1612         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1613                 goto out;
1614
1615         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1616                 goto out;
1617
1618         *dstptr += sizeof(struct compat_arpt_entry);
1619         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1620
1621         target_offset = e->target_offset - (origsize - *size);
1622
1623         t = arpt_get_target(e);
1624         ret = xt_compat_target_to_user(t, dstptr, size);
1625         if (ret)
1626                 goto out;
1627         ret = -EFAULT;
1628         next_offset = e->next_offset - (origsize - *size);
1629         if (put_user(target_offset, &ce->target_offset))
1630                 goto out;
1631         if (put_user(next_offset, &ce->next_offset))
1632                 goto out;
1633
1634         (*i)++;
1635         return 0;
1636 out:
1637         return ret;
1638 }
1639
1640 static int compat_copy_entries_to_user(unsigned int total_size,
1641                                        struct xt_table *table,
1642                                        void __user *userptr)
1643 {
1644         struct xt_counters *counters;
1645         const struct xt_table_info *private = table->private;
1646         void __user *pos;
1647         unsigned int size;
1648         int ret = 0;
1649         void *loc_cpu_entry;
1650         unsigned int i = 0;
1651
1652         counters = alloc_counters(table);
1653         if (IS_ERR(counters))
1654                 return PTR_ERR(counters);
1655
1656         /* choose the copy on our node/cpu */
1657         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1658         pos = userptr;
1659         size = total_size;
1660         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1661                                  compat_copy_entry_to_user,
1662                                  &pos, &size, counters, &i);
1663         vfree(counters);
1664         return ret;
1665 }
1666
1667 struct compat_arpt_get_entries {
1668         char name[ARPT_TABLE_MAXNAMELEN];
1669         compat_uint_t size;
1670         struct compat_arpt_entry entrytable[0];
1671 };
1672
1673 static int compat_get_entries(struct net *net,
1674                               struct compat_arpt_get_entries __user *uptr,
1675                               int *len)
1676 {
1677         int ret;
1678         struct compat_arpt_get_entries get;
1679         struct xt_table *t;
1680
1681         if (*len < sizeof(get)) {
1682                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1683                 return -EINVAL;
1684         }
1685         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1686                 return -EFAULT;
1687         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1688                 duprintf("compat_get_entries: %u != %zu\n",
1689                          *len, sizeof(get) + get.size);
1690                 return -EINVAL;
1691         }
1692
1693         xt_compat_lock(NFPROTO_ARP);
1694         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1695         if (t && !IS_ERR(t)) {
1696                 const struct xt_table_info *private = t->private;
1697                 struct xt_table_info info;
1698
1699                 duprintf("t->private->number = %u\n", private->number);
1700                 ret = compat_table_info(private, &info);
1701                 if (!ret && get.size == info.size) {
1702                         ret = compat_copy_entries_to_user(private->size,
1703                                                           t, uptr->entrytable);
1704                 } else if (!ret) {
1705                         duprintf("compat_get_entries: I've got %u not %u!\n",
1706                                  private->size, get.size);
1707                         ret = -EAGAIN;
1708                 }
1709                 xt_compat_flush_offsets(NFPROTO_ARP);
1710                 module_put(t->me);
1711                 xt_table_unlock(t);
1712         } else
1713                 ret = t ? PTR_ERR(t) : -ENOENT;
1714
1715         xt_compat_unlock(NFPROTO_ARP);
1716         return ret;
1717 }
1718
1719 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1720
1721 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1722                                   int *len)
1723 {
1724         int ret;
1725
1726         if (!capable(CAP_NET_ADMIN))
1727                 return -EPERM;
1728
1729         switch (cmd) {
1730         case ARPT_SO_GET_INFO:
1731                 ret = get_info(sock_net(sk), user, len, 1);
1732                 break;
1733         case ARPT_SO_GET_ENTRIES:
1734                 ret = compat_get_entries(sock_net(sk), user, len);
1735                 break;
1736         default:
1737                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1738         }
1739         return ret;
1740 }
1741 #endif
1742
1743 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1744 {
1745         int ret;
1746
1747         if (!capable(CAP_NET_ADMIN))
1748                 return -EPERM;
1749
1750         switch (cmd) {
1751         case ARPT_SO_SET_REPLACE:
1752                 ret = do_replace(sock_net(sk), user, len);
1753                 break;
1754
1755         case ARPT_SO_SET_ADD_COUNTERS:
1756                 ret = do_add_counters(sock_net(sk), user, len, 0);
1757                 break;
1758
1759         default:
1760                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1761                 ret = -EINVAL;
1762         }
1763
1764         return ret;
1765 }
1766
1767 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1768 {
1769         int ret;
1770
1771         if (!capable(CAP_NET_ADMIN))
1772                 return -EPERM;
1773
1774         switch (cmd) {
1775         case ARPT_SO_GET_INFO:
1776                 ret = get_info(sock_net(sk), user, len, 0);
1777                 break;
1778
1779         case ARPT_SO_GET_ENTRIES:
1780                 ret = get_entries(sock_net(sk), user, len);
1781                 break;
1782
1783         case ARPT_SO_GET_REVISION_TARGET: {
1784                 struct xt_get_revision rev;
1785
1786                 if (*len != sizeof(rev)) {
1787                         ret = -EINVAL;
1788                         break;
1789                 }
1790                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1791                         ret = -EFAULT;
1792                         break;
1793                 }
1794
1795                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1796                                                          rev.revision, 1, &ret),
1797                                         "arpt_%s", rev.name);
1798                 break;
1799         }
1800
1801         default:
1802                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1803                 ret = -EINVAL;
1804         }
1805
1806         return ret;
1807 }
1808
1809 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1810                                      const struct arpt_replace *repl)
1811 {
1812         int ret;
1813         struct xt_table_info *newinfo;
1814         struct xt_table_info bootstrap
1815                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1816         void *loc_cpu_entry;
1817         struct xt_table *new_table;
1818
1819         newinfo = xt_alloc_table_info(repl->size);
1820         if (!newinfo) {
1821                 ret = -ENOMEM;
1822                 goto out;
1823         }
1824
1825         /* choose the copy on our node/cpu */
1826         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1827         memcpy(loc_cpu_entry, repl->entries, repl->size);
1828
1829         ret = translate_table(table->name, table->valid_hooks,
1830                               newinfo, loc_cpu_entry, repl->size,
1831                               repl->num_entries,
1832                               repl->hook_entry,
1833                               repl->underflow);
1834
1835         duprintf("arpt_register_table: translate table gives %d\n", ret);
1836         if (ret != 0)
1837                 goto out_free;
1838
1839         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1840         if (IS_ERR(new_table)) {
1841                 ret = PTR_ERR(new_table);
1842                 goto out_free;
1843         }
1844         return new_table;
1845
1846 out_free:
1847         xt_free_table_info(newinfo);
1848 out:
1849         return ERR_PTR(ret);
1850 }
1851
1852 void arpt_unregister_table(struct xt_table *table)
1853 {
1854         struct xt_table_info *private;
1855         void *loc_cpu_entry;
1856         struct module *table_owner = table->me;
1857
1858         private = xt_unregister_table(table);
1859
1860         /* Decrease module usage counts and free resources */
1861         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1862         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1863                            cleanup_entry, NULL);
1864         if (private->number > private->initial_entries)
1865                 module_put(table_owner);
1866         xt_free_table_info(private);
1867 }
1868
1869 /* The built-in targets: standard (NULL) and error. */
1870 static struct xt_target arpt_standard_target __read_mostly = {
1871         .name           = ARPT_STANDARD_TARGET,
1872         .targetsize     = sizeof(int),
1873         .family         = NFPROTO_ARP,
1874 #ifdef CONFIG_COMPAT
1875         .compatsize     = sizeof(compat_int_t),
1876         .compat_from_user = compat_standard_from_user,
1877         .compat_to_user = compat_standard_to_user,
1878 #endif
1879 };
1880
1881 static struct xt_target arpt_error_target __read_mostly = {
1882         .name           = ARPT_ERROR_TARGET,
1883         .target         = arpt_error,
1884         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1885         .family         = NFPROTO_ARP,
1886 };
1887
1888 static struct nf_sockopt_ops arpt_sockopts = {
1889         .pf             = PF_INET,
1890         .set_optmin     = ARPT_BASE_CTL,
1891         .set_optmax     = ARPT_SO_SET_MAX+1,
1892         .set            = do_arpt_set_ctl,
1893 #ifdef CONFIG_COMPAT
1894         .compat_set     = compat_do_arpt_set_ctl,
1895 #endif
1896         .get_optmin     = ARPT_BASE_CTL,
1897         .get_optmax     = ARPT_SO_GET_MAX+1,
1898         .get            = do_arpt_get_ctl,
1899 #ifdef CONFIG_COMPAT
1900         .compat_get     = compat_do_arpt_get_ctl,
1901 #endif
1902         .owner          = THIS_MODULE,
1903 };
1904
1905 static int __net_init arp_tables_net_init(struct net *net)
1906 {
1907         return xt_proto_init(net, NFPROTO_ARP);
1908 }
1909
1910 static void __net_exit arp_tables_net_exit(struct net *net)
1911 {
1912         xt_proto_fini(net, NFPROTO_ARP);
1913 }
1914
1915 static struct pernet_operations arp_tables_net_ops = {
1916         .init = arp_tables_net_init,
1917         .exit = arp_tables_net_exit,
1918 };
1919
1920 static int __init arp_tables_init(void)
1921 {
1922         int ret;
1923
1924         ret = register_pernet_subsys(&arp_tables_net_ops);
1925         if (ret < 0)
1926                 goto err1;
1927
1928         /* Noone else will be downing sem now, so we won't sleep */
1929         ret = xt_register_target(&arpt_standard_target);
1930         if (ret < 0)
1931                 goto err2;
1932         ret = xt_register_target(&arpt_error_target);
1933         if (ret < 0)
1934                 goto err3;
1935
1936         /* Register setsockopt */
1937         ret = nf_register_sockopt(&arpt_sockopts);
1938         if (ret < 0)
1939                 goto err4;
1940
1941         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1942         return 0;
1943
1944 err4:
1945         xt_unregister_target(&arpt_error_target);
1946 err3:
1947         xt_unregister_target(&arpt_standard_target);
1948 err2:
1949         unregister_pernet_subsys(&arp_tables_net_ops);
1950 err1:
1951         return ret;
1952 }
1953
1954 static void __exit arp_tables_fini(void)
1955 {
1956         nf_unregister_sockopt(&arpt_sockopts);
1957         xt_unregister_target(&arpt_error_target);
1958         xt_unregister_target(&arpt_standard_target);
1959         unregister_pernet_subsys(&arp_tables_net_ops);
1960 }
1961
1962 EXPORT_SYMBOL(arpt_register_table);
1963 EXPORT_SYMBOL(arpt_unregister_table);
1964 EXPORT_SYMBOL(arpt_do_table);
1965
1966 module_init(arp_tables_init);
1967 module_exit(arp_tables_fini);