SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv4/netfilter/arp_tables.c

   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 (t->verdict < -NF_MAX_VERDICT - 1) {
 392                                         duprintf("mark_source_chains: bad "
 393                                                 "negative verdict (%i)\n",
 394                                                                 t->verdict);
 395                                         return 0;
 396                                 }
 397
 398                                 /* Return: backtrack through the last
 399                                  * big jump.
 400                                  */
 401                                 do {
 402                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 403                                         oldpos = pos;
 404                                         pos = e->counters.pcnt;
 405                                         e->counters.pcnt = 0;
 406
 407                                         /* We're at the start. */
 408                                         if (pos == oldpos)
 409                                                 goto next;
 410
 411                                         e = (struct arpt_entry *)
 412                                                 (entry0 + pos);
 413                                 } while (oldpos == pos + e->next_offset);
 414
 415                                 /* Move along one */
 416                                 size = e->next_offset;
 417                                 e = (struct arpt_entry *)
 418                                         (entry0 + pos + size);
 419                                 e->counters.pcnt = pos;
 420                                 pos += size;
 421                         } else {
 422                                 int newpos = t->verdict;
 423
 424                                 if (strcmp(t->target.u.user.name,
 425                                            ARPT_STANDARD_TARGET) == 0
 426                                     && newpos >= 0) {
 427                                         if (newpos > newinfo->size -
 428                                                 sizeof(struct arpt_entry)) {
 429                                                 duprintf("mark_source_chains: "
 430                                                         "bad verdict (%i)\n",
 431                                                                 newpos);
 432                                                 return 0;
 433                                         }
 434
 435                                         /* This a jump; chase it. */
 436                                         duprintf("Jump rule %u -> %u\n",
 437                                                  pos, newpos);
 438                                 } else {
 439                                         /* ... this is a fallthru */
 440                                         newpos = pos + e->next_offset;
 441                                 }
 442                                 e = (struct arpt_entry *)
 443                                         (entry0 + newpos);
 444                                 e->counters.pcnt = pos;
 445                                 pos = newpos;
 446                         }
 447                 }
 448                 next:
 449                 duprintf("Finished chain %u\n", hook);
 450         }
 451         return 1;
 452 }
 453
 454 static inline int check_entry(struct arpt_entry *e, const char *name)
 455 {
 456         const struct arpt_entry_target *t;
 457
 458         if (!arp_checkentry(&e->arp)) {
 459                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 460                 return -EINVAL;
 461         }
 462
 463         if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
 464                 return -EINVAL;
 465
 466         t = arpt_get_target(e);
 467         if (e->target_offset + t->u.target_size > e->next_offset)
 468                 return -EINVAL;
 469
 470         return 0;
 471 }
 472
 473 static inline int check_target(struct arpt_entry *e, const char *name)
 474 {
 475         struct arpt_entry_target *t = arpt_get_target(e);
 476         int ret;
 477         struct xt_tgchk_param par = {
 478                 .table     = name,
 479                 .entryinfo = e,
 480                 .target    = t->u.kernel.target,
 481                 .targinfo  = t->data,
 482                 .hook_mask = e->comefrom,
 483                 .family    = NFPROTO_ARP,
 484         };
 485
 486         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 487         if (ret < 0) {
 488                 duprintf("arp_tables: check failed for `%s'.\n",
 489                          t->u.kernel.target->name);
 490                 return ret;
 491         }
 492         return 0;
 493 }
 494
 495 static inline int
 496 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 497                  unsigned int *i)
 498 {
 499         struct arpt_entry_target *t;
 500         struct xt_target *target;
 501         int ret;
 502
 503         ret = check_entry(e, name);
 504         if (ret)
 505                 return ret;
 506
 507         t = arpt_get_target(e);
 508         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
 509                                                         t->u.user.name,
 510                                                         t->u.user.revision),
 511                                          "arpt_%s", t->u.user.name);
 512         if (IS_ERR(target) || !target) {
 513                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 514                 ret = target ? PTR_ERR(target) : -ENOENT;
 515                 goto out;
 516         }
 517         t->u.kernel.target = target;
 518
 519         ret = check_target(e, name);
 520         if (ret)
 521                 goto err;
 522
 523         (*i)++;
 524         return 0;
 525 err:
 526         module_put(t->u.kernel.target->me);
 527 out:
 528         return ret;
 529 }
 530
 531 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 532                                              struct xt_table_info *newinfo,
 533                                              unsigned char *base,
 534                                              unsigned char *limit,
 535                                              const unsigned int *hook_entries,
 536                                              const unsigned int *underflows,
 537                                              unsigned int *i)
 538 {
 539         unsigned int h;
 540
 541         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 542             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 543                 duprintf("Bad offset %p\n", e);
 544                 return -EINVAL;
 545         }
 546
 547         if (e->next_offset
 548             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 549                 duprintf("checking: element %p size %u\n",
 550                          e, e->next_offset);
 551                 return -EINVAL;
 552         }
 553
 554         /* Check hooks & underflows */
 555         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 556                 if ((unsigned char *)e - base == hook_entries[h])
 557                         newinfo->hook_entry[h] = hook_entries[h];
 558                 if ((unsigned char *)e - base == underflows[h])
 559                         newinfo->underflow[h] = underflows[h];
 560         }
 561
 562         /* FIXME: underflows must be unconditional, standard verdicts
 563            < 0 (not ARPT_RETURN). --RR */
 564
 565         /* Clear counters and comefrom */
 566         e->counters = ((struct xt_counters) { 0, 0 });
 567         e->comefrom = 0;
 568
 569         (*i)++;
 570         return 0;
 571 }
 572
 573 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 574 {
 575         struct xt_tgdtor_param par;
 576         struct arpt_entry_target *t;
 577
 578         if (i && (*i)-- == 0)
 579                 return 1;
 580
 581         t = arpt_get_target(e);
 582         par.target   = t->u.kernel.target;
 583         par.targinfo = t->data;
 584         par.family   = NFPROTO_ARP;
 585         if (par.target->destroy != NULL)
 586                 par.target->destroy(&par);
 587         module_put(par.target->me);
 588         return 0;
 589 }
 590
 591 /* Checks and translates the user-supplied table segment (held in
 592  * newinfo).
 593  */
 594 static int translate_table(const char *name,
 595                            unsigned int valid_hooks,
 596                            struct xt_table_info *newinfo,
 597                            void *entry0,
 598                            unsigned int size,
 599                            unsigned int number,
 600                            const unsigned int *hook_entries,
 601                            const unsigned int *underflows)
 602 {
 603         unsigned int i;
 604         int ret;
 605
 606         newinfo->size = size;
 607         newinfo->number = number;
 608
 609         /* Init all hooks to impossible value. */
 610         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 611                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 612                 newinfo->underflow[i] = 0xFFFFFFFF;
 613         }
 614
 615         duprintf("translate_table: size %u\n", newinfo->size);
 616         i = 0;
 617
 618         /* Walk through entries, checking offsets. */
 619         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 620                                  check_entry_size_and_hooks,
 621                                  newinfo,
 622                                  entry0,
 623                                  entry0 + size,
 624                                  hook_entries, underflows, &i);
 625         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 626         if (ret != 0)
 627                 return ret;
 628
 629         if (i != number) {
 630                 duprintf("translate_table: %u not %u entries\n",
 631                          i, number);
 632                 return -EINVAL;
 633         }
 634
 635         /* Check hooks all assigned */
 636         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 637                 /* Only hooks which are valid */
 638                 if (!(valid_hooks & (1 << i)))
 639                         continue;
 640                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 641                         duprintf("Invalid hook entry %u %u\n",
 642                                  i, hook_entries[i]);
 643                         return -EINVAL;
 644                 }
 645                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 646                         duprintf("Invalid underflow %u %u\n",
 647                                  i, underflows[i]);
 648                         return -EINVAL;
 649                 }
 650         }
 651
 652         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 653                 duprintf("Looping hook\n");
 654                 return -ELOOP;
 655         }
 656
 657         /* Finally, each sanity check must pass */
 658         i = 0;
 659         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 660                                  find_check_entry, name, size, &i);
 661
 662         if (ret != 0) {
 663                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 664                                 cleanup_entry, &i);
 665                 return ret;
 666         }
 667
 668         /* And one copy for every other CPU */
 669         for_each_possible_cpu(i) {
 670                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 671                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 672         }
 673
 674         return ret;
 675 }
 676
 677 /* Gets counters. */
 678 static inline int add_entry_to_counter(const struct arpt_entry *e,
 679                                        struct xt_counters total[],
 680                                        unsigned int *i)
 681 {
 682         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 683
 684         (*i)++;
 685         return 0;
 686 }
 687
 688 static inline int set_entry_to_counter(const struct arpt_entry *e,
 689                                        struct xt_counters total[],
 690                                        unsigned int *i)
 691 {
 692         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 693
 694         (*i)++;
 695         return 0;
 696 }
 697
 698 static void get_counters(const struct xt_table_info *t,
 699                          struct xt_counters counters[])
 700 {
 701         unsigned int cpu;
 702         unsigned int i;
 703         unsigned int curcpu;
 704
 705         /* Instead of clearing (by a previous call to memset())
 706          * the counters and using adds, we set the counters
 707          * with data used by 'current' CPU
 708          * We dont care about preemption here.
 709          */
 710         curcpu = raw_smp_processor_id();
 711
 712         i = 0;
 713         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 714                            t->size,
 715                            set_entry_to_counter,
 716                            counters,
 717                            &i);
 718
 719         for_each_possible_cpu(cpu) {
 720                 if (cpu == curcpu)
 721                         continue;
 722                 i = 0;
 723                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 724                                    t->size,
 725                                    add_entry_to_counter,
 726                                    counters,
 727                                    &i);
 728         }
 729 }
 730
 731
 732 /* We're lazy, and add to the first CPU; overflow works its fey magic
 733  * and everything is OK. */
 734 static int
 735 add_counter_to_entry(struct arpt_entry *e,
 736                      const struct xt_counters addme[],
 737                      unsigned int *i)
 738 {
 739         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
 740
 741         (*i)++;
 742         return 0;
 743 }
 744
 745 /* Take values from counters and add them back onto the current cpu */
 746 static void put_counters(struct xt_table_info *t,
 747                          const struct xt_counters counters[])
 748 {
 749         unsigned int i, cpu;
 750
 751         local_bh_disable();
 752         cpu = smp_processor_id();
 753         i = 0;
 754         ARPT_ENTRY_ITERATE(t->entries[cpu],
 755                           t->size,
 756                           add_counter_to_entry,
 757                           counters,
 758                           &i);
 759         local_bh_enable();
 760 }
 761
 762 static inline int
 763 zero_entry_counter(struct arpt_entry *e, void *arg)
 764 {
 765         e->counters.bcnt = 0;
 766         e->counters.pcnt = 0;
 767         return 0;
 768 }
 769
 770 static void
 771 clone_counters(struct xt_table_info *newinfo, const struct xt_table_info *info)
 772 {
 773         unsigned int cpu;
 774         const void *loc_cpu_entry = info->entries[raw_smp_processor_id()];
 775
 776         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 777         for_each_possible_cpu(cpu) {
 778                 memcpy(newinfo->entries[cpu], loc_cpu_entry, info->size);
 779                 ARPT_ENTRY_ITERATE(newinfo->entries[cpu], newinfo->size,
 780                                   zero_entry_counter, NULL);
 781         }
 782 }
 783
 784 static struct xt_counters *alloc_counters(struct xt_table *table)
 785 {
 786         unsigned int countersize;
 787         struct xt_counters *counters;
 788         struct xt_table_info *private = table->private;
 789         struct xt_table_info *info;
 790
 791         /* We need atomic snapshot of counters: rest doesn't change
 792          * (other than comefrom, which userspace doesn't care
 793          * about).
 794          */
 795         countersize = sizeof(struct xt_counters) * private->number;
 796         counters = vmalloc_node(countersize, numa_node_id());
 797
 798         if (counters == NULL)
 799                 goto nomem;
 800
 801         info = xt_alloc_table_info(private->size);
 802         if (!info)
 803                 goto free_counters;
 804
 805         clone_counters(info, private);
 806
 807         mutex_lock(&table->lock);
 808         xt_table_entry_swap_rcu(private, info);
 809         synchronize_net();      /* Wait until smoke has cleared */
 810
 811         get_counters(info, counters);
 812         put_counters(private, counters);
 813         mutex_unlock(&table->lock);
 814
 815         xt_free_table_info(info);
 816
 817         return counters;
 818
 819  free_counters:
 820         vfree(counters);
 821  nomem:
 822         return ERR_PTR(-ENOMEM);
 823 }
 824
 825 static int copy_entries_to_user(unsigned int total_size,
 826                                 struct xt_table *table,
 827                                 void __user *userptr)
 828 {
 829         unsigned int off, num;
 830         struct arpt_entry *e;
 831         struct xt_counters *counters;
 832         struct xt_table_info *private = table->private;
 833         int ret = 0;
 834         void *loc_cpu_entry;
 835
 836         counters = alloc_counters(table);
 837         if (IS_ERR(counters))
 838                 return PTR_ERR(counters);
 839
 840         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 841         /* ... then copy entire thing ... */
 842         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 843                 ret = -EFAULT;
 844                 goto free_counters;
 845         }
 846
 847         /* FIXME: use iterator macros --RR */
 848         /* ... then go back and fix counters and names */
 849         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 850                 struct arpt_entry_target *t;
 851
 852                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 853                 if (copy_to_user(userptr + off
 854                                  + offsetof(struct arpt_entry, counters),
 855                                  &counters[num],
 856                                  sizeof(counters[num])) != 0) {
 857                         ret = -EFAULT;
 858                         goto free_counters;
 859                 }
 860
 861                 t = arpt_get_target(e);
 862                 if (copy_to_user(userptr + off + e->target_offset
 863                                  + offsetof(struct arpt_entry_target,
 864                                             u.user.name),
 865                                  t->u.kernel.target->name,
 866                                  strlen(t->u.kernel.target->name)+1) != 0) {
 867                         ret = -EFAULT;
 868                         goto free_counters;
 869                 }
 870         }
 871
 872  free_counters:
 873         vfree(counters);
 874         return ret;
 875 }
 876
 877 #ifdef CONFIG_COMPAT
 878 static void compat_standard_from_user(void *dst, void *src)
 879 {
 880         int v = *(compat_int_t *)src;
 881
 882         if (v > 0)
 883                 v += xt_compat_calc_jump(NFPROTO_ARP, v);
 884         memcpy(dst, &v, sizeof(v));
 885 }
 886
 887 static int compat_standard_to_user(void __user *dst, void *src)
 888 {
 889         compat_int_t cv = *(int *)src;
 890
 891         if (cv > 0)
 892                 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 893         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 894 }
 895
 896 static int compat_calc_entry(struct arpt_entry *e,
 897                              const struct xt_table_info *info,
 898                              void *base, struct xt_table_info *newinfo)
 899 {
 900         struct arpt_entry_target *t;
 901         unsigned int entry_offset;
 902         int off, i, ret;
 903
 904         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 905         entry_offset = (void *)e - base;
 906
 907         t = arpt_get_target(e);
 908         off += xt_compat_target_offset(t->u.kernel.target);
 909         newinfo->size -= off;
 910         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 911         if (ret)
 912                 return ret;
 913
 914         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 915                 if (info->hook_entry[i] &&
 916                     (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 917                         newinfo->hook_entry[i] -= off;
 918                 if (info->underflow[i] &&
 919                     (e < (struct arpt_entry *)(base + info->underflow[i])))
 920                         newinfo->underflow[i] -= off;
 921         }
 922         return 0;
 923 }
 924
 925 static int compat_table_info(const struct xt_table_info *info,
 926                              struct xt_table_info *newinfo)
 927 {
 928         void *loc_cpu_entry;
 929
 930         if (!newinfo || !info)
 931                 return -EINVAL;
 932
 933         /* we dont care about newinfo->entries[] */
 934         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 935         newinfo->initial_entries = 0;
 936         loc_cpu_entry = info->entries[raw_smp_processor_id()];
 937         return ARPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
 938                                   compat_calc_entry, info, loc_cpu_entry,
 939                                   newinfo);
 940 }
 941 #endif
 942
 943 static int get_info(struct net *net, void __user *user, int *len, int compat)
 944 {
 945         char name[ARPT_TABLE_MAXNAMELEN];
 946         struct xt_table *t;
 947         int ret;
 948
 949         if (*len != sizeof(struct arpt_getinfo)) {
 950                 duprintf("length %u != %Zu\n", *len,
 951                          sizeof(struct arpt_getinfo));
 952                 return -EINVAL;
 953         }
 954
 955         if (copy_from_user(name, user, sizeof(name)) != 0)
 956                 return -EFAULT;
 957
 958         name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
 959 #ifdef CONFIG_COMPAT
 960         if (compat)
 961                 xt_compat_lock(NFPROTO_ARP);
 962 #endif
 963         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 964                                     "arptable_%s", name);
 965         if (t && !IS_ERR(t)) {
 966                 struct arpt_getinfo info;
 967                 const struct xt_table_info *private = t->private;
 968
 969 #ifdef CONFIG_COMPAT
 970                 if (compat) {
 971                         struct xt_table_info tmp;
 972                         ret = compat_table_info(private, &tmp);
 973                         xt_compat_flush_offsets(NFPROTO_ARP);
 974                         private = &tmp;
 975                 }
 976 #endif
 977                 info.valid_hooks = t->valid_hooks;
 978                 memcpy(info.hook_entry, private->hook_entry,
 979                        sizeof(info.hook_entry));
 980                 memcpy(info.underflow, private->underflow,
 981                        sizeof(info.underflow));
 982                 info.num_entries = private->number;
 983                 info.size = private->size;
 984                 strcpy(info.name, name);
 985
 986                 if (copy_to_user(user, &info, *len) != 0)
 987                         ret = -EFAULT;
 988                 else
 989                         ret = 0;
 990                 xt_table_unlock(t);
 991                 module_put(t->me);
 992         } else
 993                 ret = t ? PTR_ERR(t) : -ENOENT;
 994 #ifdef CONFIG_COMPAT
 995         if (compat)
 996                 xt_compat_unlock(NFPROTO_ARP);
 997 #endif
 998         return ret;
 999 }
1000
1001 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
1002                        int *len)
1003 {
1004         int ret;
1005         struct arpt_get_entries get;
1006         struct xt_table *t;
1007
1008         if (*len < sizeof(get)) {
1009                 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1010                 return -EINVAL;
1011         }
1012         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1013                 return -EFAULT;
1014         if (*len != sizeof(struct arpt_get_entries) + get.size) {
1015                 duprintf("get_entries: %u != %Zu\n", *len,
1016                          sizeof(struct arpt_get_entries) + get.size);
1017                 return -EINVAL;
1018         }
1019
1020         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1021         if (t && !IS_ERR(t)) {
1022                 const struct xt_table_info *private = t->private;
1023
1024                 duprintf("t->private->number = %u\n",
1025                          private->number);
1026                 if (get.size == private->size)
1027                         ret = copy_entries_to_user(private->size,
1028                                                    t, uptr->entrytable);
1029                 else {
1030                         duprintf("get_entries: I've got %u not %u!\n",
1031                                  private->size, get.size);
1032                         ret = -EAGAIN;
1033                 }
1034                 module_put(t->me);
1035                 xt_table_unlock(t);
1036         } else
1037                 ret = t ? PTR_ERR(t) : -ENOENT;
1038
1039         return ret;
1040 }
1041
1042 static int __do_replace(struct net *net, const char *name,
1043                         unsigned int valid_hooks,
1044                         struct xt_table_info *newinfo,
1045                         unsigned int num_counters,
1046                         void __user *counters_ptr)
1047 {
1048         int ret;
1049         struct xt_table *t;
1050         struct xt_table_info *oldinfo;
1051         struct xt_counters *counters;
1052         void *loc_cpu_old_entry;
1053
1054         ret = 0;
1055         counters = vmalloc_node(num_counters * sizeof(struct xt_counters),
1056                                 numa_node_id());
1057         if (!counters) {
1058                 ret = -ENOMEM;
1059                 goto out;
1060         }
1061
1062         t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1063                                     "arptable_%s", name);
1064         if (!t || IS_ERR(t)) {
1065                 ret = t ? PTR_ERR(t) : -ENOENT;
1066                 goto free_newinfo_counters_untrans;
1067         }
1068
1069         /* You lied! */
1070         if (valid_hooks != t->valid_hooks) {
1071                 duprintf("Valid hook crap: %08X vs %08X\n",
1072                          valid_hooks, t->valid_hooks);
1073                 ret = -EINVAL;
1074                 goto put_module;
1075         }
1076
1077         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1078         if (!oldinfo)
1079                 goto put_module;
1080
1081         /* Update module usage count based on number of rules */
1082         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1083                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1084         if ((oldinfo->number > oldinfo->initial_entries) ||
1085             (newinfo->number <= oldinfo->initial_entries))
1086                 module_put(t->me);
1087         if ((oldinfo->number > oldinfo->initial_entries) &&
1088             (newinfo->number <= oldinfo->initial_entries))
1089                 module_put(t->me);
1090
1091         /* Get the old counters. */
1092         get_counters(oldinfo, counters);
1093         /* Decrease module usage counts and free resource */
1094         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1095         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,
1096                            NULL);
1097
1098         xt_free_table_info(oldinfo);
1099         if (copy_to_user(counters_ptr, counters,
1100                          sizeof(struct xt_counters) * num_counters) != 0)
1101                 ret = -EFAULT;
1102         vfree(counters);
1103         xt_table_unlock(t);
1104         return ret;
1105
1106  put_module:
1107         module_put(t->me);
1108         xt_table_unlock(t);
1109  free_newinfo_counters_untrans:
1110         vfree(counters);
1111  out:
1112         return ret;
1113 }
1114
1115 static int do_replace(struct net *net, void __user *user, unsigned int len)
1116 {
1117         int ret;
1118         struct arpt_replace tmp;
1119         struct xt_table_info *newinfo;
1120         void *loc_cpu_entry;
1121
1122         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1123                 return -EFAULT;
1124
1125         /* overflow check */
1126         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1127                 return -ENOMEM;
1128
1129         newinfo = xt_alloc_table_info(tmp.size);
1130         if (!newinfo)
1131                 return -ENOMEM;
1132
1133         /* choose the copy that is on our node/cpu */
1134         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1135         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1136                            tmp.size) != 0) {
1137                 ret = -EFAULT;
1138                 goto free_newinfo;
1139         }
1140
1141         ret = translate_table(tmp.name, tmp.valid_hooks,
1142                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
1143                               tmp.hook_entry, tmp.underflow);
1144         if (ret != 0)
1145                 goto free_newinfo;
1146
1147         duprintf("arp_tables: Translated table\n");
1148
1149         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1150                            tmp.num_counters, tmp.counters);
1151         if (ret)
1152                 goto free_newinfo_untrans;
1153         return 0;
1154
1155  free_newinfo_untrans:
1156         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1157  free_newinfo:
1158         xt_free_table_info(newinfo);
1159         return ret;
1160 }
1161
1162 static int do_add_counters(struct net *net, void __user *user, unsigned int len,
1163                            int compat)
1164 {
1165         unsigned int i;
1166         struct xt_counters_info tmp;
1167         struct xt_counters *paddc;
1168         unsigned int num_counters;
1169         const char *name;
1170         int size;
1171         void *ptmp;
1172         struct xt_table *t;
1173         const struct xt_table_info *private;
1174         int ret = 0;
1175         void *loc_cpu_entry;
1176 #ifdef CONFIG_COMPAT
1177         struct compat_xt_counters_info compat_tmp;
1178
1179         if (compat) {
1180                 ptmp = &compat_tmp;
1181                 size = sizeof(struct compat_xt_counters_info);
1182         } else
1183 #endif
1184         {
1185                 ptmp = &tmp;
1186                 size = sizeof(struct xt_counters_info);
1187         }
1188
1189         if (copy_from_user(ptmp, user, size) != 0)
1190                 return -EFAULT;
1191
1192 #ifdef CONFIG_COMPAT
1193         if (compat) {
1194                 num_counters = compat_tmp.num_counters;
1195                 name = compat_tmp.name;
1196         } else
1197 #endif
1198         {
1199                 num_counters = tmp.num_counters;
1200                 name = tmp.name;
1201         }
1202
1203         if (len != size + num_counters * sizeof(struct xt_counters))
1204                 return -EINVAL;
1205
1206         paddc = vmalloc_node(len - size, numa_node_id());
1207         if (!paddc)
1208                 return -ENOMEM;
1209
1210         if (copy_from_user(paddc, user + size, len - size) != 0) {
1211                 ret = -EFAULT;
1212                 goto free;
1213         }
1214
1215         t = xt_find_table_lock(net, NFPROTO_ARP, name);
1216         if (!t || IS_ERR(t)) {
1217                 ret = t ? PTR_ERR(t) : -ENOENT;
1218                 goto free;
1219         }
1220
1221         mutex_lock(&t->lock);
1222         private = t->private;
1223         if (private->number != num_counters) {
1224                 ret = -EINVAL;
1225                 goto unlock_up_free;
1226         }
1227
1228         preempt_disable();
1229         i = 0;
1230         /* Choose the copy that is on our node */
1231         loc_cpu_entry = private->entries[smp_processor_id()];
1232         ARPT_ENTRY_ITERATE(loc_cpu_entry,
1233                            private->size,
1234                            add_counter_to_entry,
1235                            paddc,
1236                            &i);
1237         preempt_enable();
1238  unlock_up_free:
1239         mutex_unlock(&t->lock);
1240
1241         xt_table_unlock(t);
1242         module_put(t->me);
1243  free:
1244         vfree(paddc);
1245
1246         return ret;
1247 }
1248
1249 #ifdef CONFIG_COMPAT
1250 static inline int
1251 compat_release_entry(struct compat_arpt_entry *e, unsigned int *i)
1252 {
1253         struct arpt_entry_target *t;
1254
1255         if (i && (*i)-- == 0)
1256                 return 1;
1257
1258         t = compat_arpt_get_target(e);
1259         module_put(t->u.kernel.target->me);
1260         return 0;
1261 }
1262
1263 static inline int
1264 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1265                                   struct xt_table_info *newinfo,
1266                                   unsigned int *size,
1267                                   unsigned char *base,
1268                                   unsigned char *limit,
1269                                   unsigned int *hook_entries,
1270                                   unsigned int *underflows,
1271                                   unsigned int *i,
1272                                   const char *name)
1273 {
1274         struct arpt_entry_target *t;
1275         struct xt_target *target;
1276         unsigned int entry_offset;
1277         int ret, off, h;
1278
1279         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1280         if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0
1281             || (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1282                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1283                 return -EINVAL;
1284         }
1285
1286         if (e->next_offset < sizeof(struct compat_arpt_entry) +
1287                              sizeof(struct compat_xt_entry_target)) {
1288                 duprintf("checking: element %p size %u\n",
1289                          e, e->next_offset);
1290                 return -EINVAL;
1291         }
1292
1293         /* For purposes of check_entry casting the compat entry is fine */
1294         ret = check_entry((struct arpt_entry *)e, name);
1295         if (ret)
1296                 return ret;
1297
1298         off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1299         entry_offset = (void *)e - (void *)base;
1300
1301         t = compat_arpt_get_target(e);
1302         target = try_then_request_module(xt_find_target(NFPROTO_ARP,
1303                                                         t->u.user.name,
1304                                                         t->u.user.revision),
1305                                          "arpt_%s", t->u.user.name);
1306         if (IS_ERR(target) || !target) {
1307                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1308                          t->u.user.name);
1309                 ret = target ? PTR_ERR(target) : -ENOENT;
1310                 goto out;
1311         }
1312         t->u.kernel.target = target;
1313
1314         off += xt_compat_target_offset(target);
1315         *size += off;
1316         ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1317         if (ret)
1318                 goto release_target;
1319
1320         /* Check hooks & underflows */
1321         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1322                 if ((unsigned char *)e - base == hook_entries[h])
1323                         newinfo->hook_entry[h] = hook_entries[h];
1324                 if ((unsigned char *)e - base == underflows[h])
1325                         newinfo->underflow[h] = underflows[h];
1326         }
1327
1328         /* Clear counters and comefrom */
1329         memset(&e->counters, 0, sizeof(e->counters));
1330         e->comefrom = 0;
1331
1332         (*i)++;
1333         return 0;
1334
1335 release_target:
1336         module_put(t->u.kernel.target->me);
1337 out:
1338         return ret;
1339 }
1340
1341 static int
1342 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1343                             unsigned int *size, const char *name,
1344                             struct xt_table_info *newinfo, unsigned char *base)
1345 {
1346         struct arpt_entry_target *t;
1347         struct xt_target *target;
1348         struct arpt_entry *de;
1349         unsigned int origsize;
1350         int ret, h;
1351
1352         ret = 0;
1353         origsize = *size;
1354         de = (struct arpt_entry *)*dstptr;
1355         memcpy(de, e, sizeof(struct arpt_entry));
1356         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1357
1358         *dstptr += sizeof(struct arpt_entry);
1359         *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1360
1361         de->target_offset = e->target_offset - (origsize - *size);
1362         t = compat_arpt_get_target(e);
1363         target = t->u.kernel.target;
1364         xt_compat_target_from_user(t, dstptr, size);
1365
1366         de->next_offset = e->next_offset - (origsize - *size);
1367         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1368                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1369                         newinfo->hook_entry[h] -= origsize - *size;
1370                 if ((unsigned char *)de - base < newinfo->underflow[h])
1371                         newinfo->underflow[h] -= origsize - *size;
1372         }
1373         return ret;
1374 }
1375
1376 static inline int compat_check_entry(struct arpt_entry *e, const char *name,
1377                                      unsigned int *i)
1378 {
1379         int ret;
1380
1381         ret = check_target(e, name);
1382         if (ret)
1383                 return ret;
1384
1385         (*i)++;
1386         return 0;
1387 }
1388
1389 static int translate_compat_table(const char *name,
1390                                   unsigned int valid_hooks,
1391                                   struct xt_table_info **pinfo,
1392                                   void **pentry0,
1393                                   unsigned int total_size,
1394                                   unsigned int number,
1395                                   unsigned int *hook_entries,
1396                                   unsigned int *underflows)
1397 {
1398         unsigned int i, j;
1399         struct xt_table_info *newinfo, *info;
1400         void *pos, *entry0, *entry1;
1401         unsigned int size;
1402         int ret;
1403
1404         info = *pinfo;
1405         entry0 = *pentry0;
1406         size = total_size;
1407         info->number = number;
1408
1409         /* Init all hooks to impossible value. */
1410         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1411                 info->hook_entry[i] = 0xFFFFFFFF;
1412                 info->underflow[i] = 0xFFFFFFFF;
1413         }
1414
1415         duprintf("translate_compat_table: size %u\n", info->size);
1416         j = 0;
1417         xt_compat_lock(NFPROTO_ARP);
1418         /* Walk through entries, checking offsets. */
1419         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1420                                         check_compat_entry_size_and_hooks,
1421                                         info, &size, entry0,
1422                                         entry0 + total_size,
1423                                         hook_entries, underflows, &j, name);
1424         if (ret != 0)
1425                 goto out_unlock;
1426
1427         ret = -EINVAL;
1428         if (j != number) {
1429                 duprintf("translate_compat_table: %u not %u entries\n",
1430                          j, number);
1431                 goto out_unlock;
1432         }
1433
1434         /* Check hooks all assigned */
1435         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1436                 /* Only hooks which are valid */
1437                 if (!(valid_hooks & (1 << i)))
1438                         continue;
1439                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1440                         duprintf("Invalid hook entry %u %u\n",
1441                                  i, hook_entries[i]);
1442                         goto out_unlock;
1443                 }
1444                 if (info->underflow[i] == 0xFFFFFFFF) {
1445                         duprintf("Invalid underflow %u %u\n",
1446                                  i, underflows[i]);
1447                         goto out_unlock;
1448                 }
1449         }
1450
1451         ret = -ENOMEM;
1452         newinfo = xt_alloc_table_info(size);
1453         if (!newinfo)
1454                 goto out_unlock;
1455
1456         newinfo->number = number;
1457         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1458                 newinfo->hook_entry[i] = info->hook_entry[i];
1459                 newinfo->underflow[i] = info->underflow[i];
1460         }
1461         entry1 = newinfo->entries[raw_smp_processor_id()];
1462         pos = entry1;
1463         size = total_size;
1464         ret = COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size,
1465                                         compat_copy_entry_from_user,
1466                                         &pos, &size, name, newinfo, entry1);
1467         xt_compat_flush_offsets(NFPROTO_ARP);
1468         xt_compat_unlock(NFPROTO_ARP);
1469         if (ret)
1470                 goto free_newinfo;
1471
1472         ret = -ELOOP;
1473         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1474                 goto free_newinfo;
1475
1476         i = 0;
1477         ret = ARPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
1478                                  name, &i);
1479         if (ret) {
1480                 j -= i;
1481                 COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entry0, newinfo->size, i,
1482                                                    compat_release_entry, &j);
1483                 ARPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
1484                 xt_free_table_info(newinfo);
1485                 return ret;
1486         }
1487
1488         /* And one copy for every other CPU */
1489         for_each_possible_cpu(i)
1490                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1491                         memcpy(newinfo->entries[i], entry1, newinfo->size);
1492
1493         *pinfo = newinfo;
1494         *pentry0 = entry1;
1495         xt_free_table_info(info);
1496         return 0;
1497
1498 free_newinfo:
1499         xt_free_table_info(newinfo);
1500 out:
1501         COMPAT_ARPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
1502         return ret;
1503 out_unlock:
1504         xt_compat_flush_offsets(NFPROTO_ARP);
1505         xt_compat_unlock(NFPROTO_ARP);
1506         goto out;
1507 }
1508
1509 struct compat_arpt_replace {
1510         char                            name[ARPT_TABLE_MAXNAMELEN];
1511         u32                             valid_hooks;
1512         u32                             num_entries;
1513         u32                             size;
1514         u32                             hook_entry[NF_ARP_NUMHOOKS];
1515         u32                             underflow[NF_ARP_NUMHOOKS];
1516         u32                             num_counters;
1517         compat_uptr_t                   counters;
1518         struct compat_arpt_entry        entries[0];
1519 };
1520
1521 static int compat_do_replace(struct net *net, void __user *user,
1522                              unsigned int len)
1523 {
1524         int ret;
1525         struct compat_arpt_replace tmp;
1526         struct xt_table_info *newinfo;
1527         void *loc_cpu_entry;
1528
1529         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1530                 return -EFAULT;
1531
1532         /* overflow check */
1533         if (tmp.size >= INT_MAX / num_possible_cpus())
1534                 return -ENOMEM;
1535         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1536                 return -ENOMEM;
1537
1538         newinfo = xt_alloc_table_info(tmp.size);
1539         if (!newinfo)
1540                 return -ENOMEM;
1541
1542         /* choose the copy that is on our node/cpu */
1543         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1544         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1545                 ret = -EFAULT;
1546                 goto free_newinfo;
1547         }
1548
1549         ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1550                                      &newinfo, &loc_cpu_entry, tmp.size,
1551                                      tmp.num_entries, tmp.hook_entry,
1552                                      tmp.underflow);
1553         if (ret != 0)
1554                 goto free_newinfo;
1555
1556         duprintf("compat_do_replace: Translated table\n");
1557
1558         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1559                            tmp.num_counters, compat_ptr(tmp.counters));
1560         if (ret)
1561                 goto free_newinfo_untrans;
1562         return 0;
1563
1564  free_newinfo_untrans:
1565         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
1566  free_newinfo:
1567         xt_free_table_info(newinfo);
1568         return ret;
1569 }
1570
1571 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1572                                   unsigned int len)
1573 {
1574         int ret;
1575
1576         if (!capable(CAP_NET_ADMIN))
1577                 return -EPERM;
1578
1579         switch (cmd) {
1580         case ARPT_SO_SET_REPLACE:
1581                 ret = compat_do_replace(sock_net(sk), user, len);
1582                 break;
1583
1584         case ARPT_SO_SET_ADD_COUNTERS:
1585                 ret = do_add_counters(sock_net(sk), user, len, 1);
1586                 break;
1587
1588         default:
1589                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1590                 ret = -EINVAL;
1591         }
1592
1593         return ret;
1594 }
1595
1596 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1597                                      compat_uint_t *size,
1598                                      struct xt_counters *counters,
1599                                      unsigned int *i)
1600 {
1601         struct arpt_entry_target *t;
1602         struct compat_arpt_entry __user *ce;
1603         u_int16_t target_offset, next_offset;
1604         compat_uint_t origsize;
1605         int ret;
1606
1607         ret = -EFAULT;
1608         origsize = *size;
1609         ce = (struct compat_arpt_entry __user *)*dstptr;
1610         if (copy_to_user(ce, e, sizeof(struct arpt_entry)))
1611                 goto out;
1612
1613         if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
1614                 goto out;
1615
1616         *dstptr += sizeof(struct compat_arpt_entry);
1617         *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1618
1619         target_offset = e->target_offset - (origsize - *size);
1620
1621         t = arpt_get_target(e);
1622         ret = xt_compat_target_to_user(t, dstptr, size);
1623         if (ret)
1624                 goto out;
1625         ret = -EFAULT;
1626         next_offset = e->next_offset - (origsize - *size);
1627         if (put_user(target_offset, &ce->target_offset))
1628                 goto out;
1629         if (put_user(next_offset, &ce->next_offset))
1630                 goto out;
1631
1632         (*i)++;
1633         return 0;
1634 out:
1635         return ret;
1636 }
1637
1638 static int compat_copy_entries_to_user(unsigned int total_size,
1639                                        struct xt_table *table,
1640                                        void __user *userptr)
1641 {
1642         struct xt_counters *counters;
1643         const struct xt_table_info *private = table->private;
1644         void __user *pos;
1645         unsigned int size;
1646         int ret = 0;
1647         void *loc_cpu_entry;
1648         unsigned int i = 0;
1649
1650         counters = alloc_counters(table);
1651         if (IS_ERR(counters))
1652                 return PTR_ERR(counters);
1653
1654         /* choose the copy on our node/cpu */
1655         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1656         pos = userptr;
1657         size = total_size;
1658         ret = ARPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
1659                                  compat_copy_entry_to_user,
1660                                  &pos, &size, counters, &i);
1661         vfree(counters);
1662         return ret;
1663 }
1664
1665 struct compat_arpt_get_entries {
1666         char name[ARPT_TABLE_MAXNAMELEN];
1667         compat_uint_t size;
1668         struct compat_arpt_entry entrytable[0];
1669 };
1670
1671 static int compat_get_entries(struct net *net,
1672                               struct compat_arpt_get_entries __user *uptr,
1673                               int *len)
1674 {
1675         int ret;
1676         struct compat_arpt_get_entries get;
1677         struct xt_table *t;
1678
1679         if (*len < sizeof(get)) {
1680                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1681                 return -EINVAL;
1682         }
1683         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1684                 return -EFAULT;
1685         if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1686                 duprintf("compat_get_entries: %u != %zu\n",
1687                          *len, sizeof(get) + get.size);
1688                 return -EINVAL;
1689         }
1690
1691         xt_compat_lock(NFPROTO_ARP);
1692         t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1693         if (t && !IS_ERR(t)) {
1694                 const struct xt_table_info *private = t->private;
1695                 struct xt_table_info info;
1696
1697                 duprintf("t->private->number = %u\n", private->number);
1698                 ret = compat_table_info(private, &info);
1699                 if (!ret && get.size == info.size) {
1700                         ret = compat_copy_entries_to_user(private->size,
1701                                                           t, uptr->entrytable);
1702                 } else if (!ret) {
1703                         duprintf("compat_get_entries: I've got %u not %u!\n",
1704                                  private->size, get.size);
1705                         ret = -EAGAIN;
1706                 }
1707                 xt_compat_flush_offsets(NFPROTO_ARP);
1708                 module_put(t->me);
1709                 xt_table_unlock(t);
1710         } else
1711                 ret = t ? PTR_ERR(t) : -ENOENT;
1712
1713         xt_compat_unlock(NFPROTO_ARP);
1714         return ret;
1715 }
1716
1717 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1718
1719 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1720                                   int *len)
1721 {
1722         int ret;
1723
1724         if (!capable(CAP_NET_ADMIN))
1725                 return -EPERM;
1726
1727         switch (cmd) {
1728         case ARPT_SO_GET_INFO:
1729                 ret = get_info(sock_net(sk), user, len, 1);
1730                 break;
1731         case ARPT_SO_GET_ENTRIES:
1732                 ret = compat_get_entries(sock_net(sk), user, len);
1733                 break;
1734         default:
1735                 ret = do_arpt_get_ctl(sk, cmd, user, len);
1736         }
1737         return ret;
1738 }
1739 #endif
1740
1741 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1742 {
1743         int ret;
1744
1745         if (!capable(CAP_NET_ADMIN))
1746                 return -EPERM;
1747
1748         switch (cmd) {
1749         case ARPT_SO_SET_REPLACE:
1750                 ret = do_replace(sock_net(sk), user, len);
1751                 break;
1752
1753         case ARPT_SO_SET_ADD_COUNTERS:
1754                 ret = do_add_counters(sock_net(sk), user, len, 0);
1755                 break;
1756
1757         default:
1758                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1759                 ret = -EINVAL;
1760         }
1761
1762         return ret;
1763 }
1764
1765 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1766 {
1767         int ret;
1768
1769         if (!capable(CAP_NET_ADMIN))
1770                 return -EPERM;
1771
1772         switch (cmd) {
1773         case ARPT_SO_GET_INFO:
1774                 ret = get_info(sock_net(sk), user, len, 0);
1775                 break;
1776
1777         case ARPT_SO_GET_ENTRIES:
1778                 ret = get_entries(sock_net(sk), user, len);
1779                 break;
1780
1781         case ARPT_SO_GET_REVISION_TARGET: {
1782                 struct xt_get_revision rev;
1783
1784                 if (*len != sizeof(rev)) {
1785                         ret = -EINVAL;
1786                         break;
1787                 }
1788                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1789                         ret = -EFAULT;
1790                         break;
1791                 }
1792
1793                 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1794                                                          rev.revision, 1, &ret),
1795                                         "arpt_%s", rev.name);
1796                 break;
1797         }
1798
1799         default:
1800                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1801                 ret = -EINVAL;
1802         }
1803
1804         return ret;
1805 }
1806
1807 struct xt_table *arpt_register_table(struct net *net, struct xt_table *table,
1808                                      const struct arpt_replace *repl)
1809 {
1810         int ret;
1811         struct xt_table_info *newinfo;
1812         struct xt_table_info bootstrap
1813                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1814         void *loc_cpu_entry;
1815         struct xt_table *new_table;
1816
1817         newinfo = xt_alloc_table_info(repl->size);
1818         if (!newinfo) {
1819                 ret = -ENOMEM;
1820                 goto out;
1821         }
1822
1823         /* choose the copy on our node/cpu */
1824         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1825         memcpy(loc_cpu_entry, repl->entries, repl->size);
1826
1827         ret = translate_table(table->name, table->valid_hooks,
1828                               newinfo, loc_cpu_entry, repl->size,
1829                               repl->num_entries,
1830                               repl->hook_entry,
1831                               repl->underflow);
1832
1833         duprintf("arpt_register_table: translate table gives %d\n", ret);
1834         if (ret != 0)
1835                 goto out_free;
1836
1837         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1838         if (IS_ERR(new_table)) {
1839                 ret = PTR_ERR(new_table);
1840                 goto out_free;
1841         }
1842         return new_table;
1843
1844 out_free:
1845         xt_free_table_info(newinfo);
1846 out:
1847         return ERR_PTR(ret);
1848 }
1849
1850 void arpt_unregister_table(struct xt_table *table)
1851 {
1852         struct xt_table_info *private;
1853         void *loc_cpu_entry;
1854         struct module *table_owner = table->me;
1855
1856         private = xt_unregister_table(table);
1857
1858         /* Decrease module usage counts and free resources */
1859         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1860         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1861                            cleanup_entry, NULL);
1862         if (private->number > private->initial_entries)
1863                 module_put(table_owner);
1864         xt_free_table_info(private);
1865 }
1866
1867 /* The built-in targets: standard (NULL) and error. */
1868 static struct xt_target arpt_standard_target __read_mostly = {
1869         .name           = ARPT_STANDARD_TARGET,
1870         .targetsize     = sizeof(int),
1871         .family         = NFPROTO_ARP,
1872 #ifdef CONFIG_COMPAT
1873         .compatsize     = sizeof(compat_int_t),
1874         .compat_from_user = compat_standard_from_user,
1875         .compat_to_user = compat_standard_to_user,
1876 #endif
1877 };
1878
1879 static struct xt_target arpt_error_target __read_mostly = {
1880         .name           = ARPT_ERROR_TARGET,
1881         .target         = arpt_error,
1882         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1883         .family         = NFPROTO_ARP,
1884 };
1885
1886 static struct nf_sockopt_ops arpt_sockopts = {
1887         .pf             = PF_INET,
1888         .set_optmin     = ARPT_BASE_CTL,
1889         .set_optmax     = ARPT_SO_SET_MAX+1,
1890         .set            = do_arpt_set_ctl,
1891 #ifdef CONFIG_COMPAT
1892         .compat_set     = compat_do_arpt_set_ctl,
1893 #endif
1894         .get_optmin     = ARPT_BASE_CTL,
1895         .get_optmax     = ARPT_SO_GET_MAX+1,
1896         .get            = do_arpt_get_ctl,
1897 #ifdef CONFIG_COMPAT
1898         .compat_get     = compat_do_arpt_get_ctl,
1899 #endif
1900         .owner          = THIS_MODULE,
1901 };
1902
1903 static int __net_init arp_tables_net_init(struct net *net)
1904 {
1905         return xt_proto_init(net, NFPROTO_ARP);
1906 }
1907
1908 static void __net_exit arp_tables_net_exit(struct net *net)
1909 {
1910         xt_proto_fini(net, NFPROTO_ARP);
1911 }
1912
1913 static struct pernet_operations arp_tables_net_ops = {
1914         .init = arp_tables_net_init,
1915         .exit = arp_tables_net_exit,
1916 };
1917
1918 static int __init arp_tables_init(void)
1919 {
1920         int ret;
1921
1922         ret = register_pernet_subsys(&arp_tables_net_ops);
1923         if (ret < 0)
1924                 goto err1;
1925
1926         /* Noone else will be downing sem now, so we won't sleep */
1927         ret = xt_register_target(&arpt_standard_target);
1928         if (ret < 0)
1929                 goto err2;
1930         ret = xt_register_target(&arpt_error_target);
1931         if (ret < 0)
1932                 goto err3;
1933
1934         /* Register setsockopt */
1935         ret = nf_register_sockopt(&arpt_sockopts);
1936         if (ret < 0)
1937                 goto err4;
1938
1939         printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1940         return 0;
1941
1942 err4:
1943         xt_unregister_target(&arpt_error_target);
1944 err3:
1945         xt_unregister_target(&arpt_standard_target);
1946 err2:
1947         unregister_pernet_subsys(&arp_tables_net_ops);
1948 err1:
1949         return ret;
1950 }
1951
1952 static void __exit arp_tables_fini(void)
1953 {
1954         nf_unregister_sockopt(&arpt_sockopts);
1955         xt_unregister_target(&arpt_error_target);
1956         xt_unregister_target(&arpt_standard_target);
1957         unregister_pernet_subsys(&arp_tables_net_ops);
1958 }
1959
1960 EXPORT_SYMBOL(arpt_register_table);
1961 EXPORT_SYMBOL(arpt_unregister_table);
1962 EXPORT_SYMBOL(arpt_do_table);
1963
1964 module_init(arp_tables_init);
1965 module_exit(arp_tables_fini);