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
  23 #include <asm/uaccess.h>
  24 #include <linux/mutex.h>
  25
  26 #include <linux/netfilter/x_tables.h>
  27 #include <linux/netfilter_arp/arp_tables.h>
  28
  29 MODULE_LICENSE("GPL");
  30 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  31 MODULE_DESCRIPTION("arptables core");
  32
  33 /*#define DEBUG_ARP_TABLES*/
  34 /*#define DEBUG_ARP_TABLES_USER*/
  35
  36 #ifdef DEBUG_ARP_TABLES
  37 #define dprintf(format, args...)  printk(format , ## args)
  38 #else
  39 #define dprintf(format, args...)
  40 #endif
  41
  42 #ifdef DEBUG_ARP_TABLES_USER
  43 #define duprintf(format, args...) printk(format , ## args)
  44 #else
  45 #define duprintf(format, args...)
  46 #endif
  47
  48 #ifdef CONFIG_NETFILTER_DEBUG
  49 #define ARP_NF_ASSERT(x)                                        \
  50 do {                                                            \
  51         if (!(x))                                               \
  52                 printk("ARP_NF_ASSERT: %s:%s:%u\n",             \
  53                        __FUNCTION__, __FILE__, __LINE__);       \
  54 } while(0)
  55 #else
  56 #define ARP_NF_ASSERT(x)
  57 #endif
  58
  59 #include <linux/netfilter_ipv4/listhelp.h>
  60
  61 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  62                                       char *hdr_addr, int len)
  63 {
  64         int i, ret;
  65
  66         if (len > ARPT_DEV_ADDR_LEN_MAX)
  67                 len = ARPT_DEV_ADDR_LEN_MAX;
  68
  69         ret = 0;
  70         for (i = 0; i < len; i++)
  71                 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  72
  73         return (ret != 0);
  74 }
  75
  76 /* Returns whether packet matches rule or not. */
  77 static inline int arp_packet_match(const struct arphdr *arphdr,
  78                                    struct net_device *dev,
  79                                    const char *indev,
  80                                    const char *outdev,
  81                                    const struct arpt_arp *arpinfo)
  82 {
  83         char *arpptr = (char *)(arphdr + 1);
  84         char *src_devaddr, *tgt_devaddr;
  85         u32 src_ipaddr, tgt_ipaddr;
  86         int i, ret;
  87
  88 #define FWINV(bool,invflg) ((bool) ^ !!(arpinfo->invflags & invflg))
  89
  90         if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
  91                   ARPT_INV_ARPOP)) {
  92                 dprintf("ARP operation field mismatch.\n");
  93                 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
  94                         arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
  95                 return 0;
  96         }
  97
  98         if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
  99                   ARPT_INV_ARPHRD)) {
 100                 dprintf("ARP hardware address format mismatch.\n");
 101                 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 102                         arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 103                 return 0;
 104         }
 105
 106         if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 107                   ARPT_INV_ARPPRO)) {
 108                 dprintf("ARP protocol address format mismatch.\n");
 109                 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 110                         arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 111                 return 0;
 112         }
 113
 114         if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 115                   ARPT_INV_ARPHLN)) {
 116                 dprintf("ARP hardware address length mismatch.\n");
 117                 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 118                         arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 119                 return 0;
 120         }
 121
 122         src_devaddr = arpptr;
 123         arpptr += dev->addr_len;
 124         memcpy(&src_ipaddr, arpptr, sizeof(u32));
 125         arpptr += sizeof(u32);
 126         tgt_devaddr = arpptr;
 127         arpptr += dev->addr_len;
 128         memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 129
 130         if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 131                   ARPT_INV_SRCDEVADDR) ||
 132             FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 133                   ARPT_INV_TGTDEVADDR)) {
 134                 dprintf("Source or target device address mismatch.\n");
 135
 136                 return 0;
 137         }
 138
 139         if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 140                   ARPT_INV_SRCIP) ||
 141             FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 142                   ARPT_INV_TGTIP)) {
 143                 dprintf("Source or target IP address mismatch.\n");
 144
 145                 dprintf("SRC: %u.%u.%u.%u. Mask: %u.%u.%u.%u. Target: %u.%u.%u.%u.%s\n",
 146                         NIPQUAD(src_ipaddr),
 147                         NIPQUAD(arpinfo->smsk.s_addr),
 148                         NIPQUAD(arpinfo->src.s_addr),
 149                         arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 150                 dprintf("TGT: %u.%u.%u.%u Mask: %u.%u.%u.%u Target: %u.%u.%u.%u.%s\n",
 151                         NIPQUAD(tgt_ipaddr),
 152                         NIPQUAD(arpinfo->tmsk.s_addr),
 153                         NIPQUAD(arpinfo->tgt.s_addr),
 154                         arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 155                 return 0;
 156         }
 157
 158         /* Look for ifname matches.  */
 159         for (i = 0, ret = 0; i < IFNAMSIZ; i++) {
 160                 ret |= (indev[i] ^ arpinfo->iniface[i])
 161                         & arpinfo->iniface_mask[i];
 162         }
 163
 164         if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 165                 dprintf("VIA in mismatch (%s vs %s).%s\n",
 166                         indev, arpinfo->iniface,
 167                         arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 168                 return 0;
 169         }
 170
 171         for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
 172                 unsigned long odev;
 173                 memcpy(&odev, outdev + i*sizeof(unsigned long),
 174                        sizeof(unsigned long));
 175                 ret |= (odev
 176                         ^ ((const unsigned long *)arpinfo->outiface)[i])
 177                         & ((const unsigned long *)arpinfo->outiface_mask)[i];
 178         }
 179
 180         if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 181                 dprintf("VIA out mismatch (%s vs %s).%s\n",
 182                         outdev, arpinfo->outiface,
 183                         arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 184                 return 0;
 185         }
 186
 187         return 1;
 188 }
 189
 190 static inline int arp_checkentry(const struct arpt_arp *arp)
 191 {
 192         if (arp->flags & ~ARPT_F_MASK) {
 193                 duprintf("Unknown flag bits set: %08X\n",
 194                          arp->flags & ~ARPT_F_MASK);
 195                 return 0;
 196         }
 197         if (arp->invflags & ~ARPT_INV_MASK) {
 198                 duprintf("Unknown invflag bits set: %08X\n",
 199                          arp->invflags & ~ARPT_INV_MASK);
 200                 return 0;
 201         }
 202
 203         return 1;
 204 }
 205
 206 static unsigned int arpt_error(struct sk_buff **pskb,
 207                                const struct net_device *in,
 208                                const struct net_device *out,
 209                                unsigned int hooknum,
 210                                const struct xt_target *target,
 211                                const void *targinfo,
 212                                void *userinfo)
 213 {
 214         if (net_ratelimit())
 215                 printk("arp_tables: error: '%s'\n", (char *)targinfo);
 216
 217         return NF_DROP;
 218 }
 219
 220 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
 221 {
 222         return (struct arpt_entry *)(base + offset);
 223 }
 224
 225 unsigned int arpt_do_table(struct sk_buff **pskb,
 226                            unsigned int hook,
 227                            const struct net_device *in,
 228                            const struct net_device *out,
 229                            struct arpt_table *table,
 230                            void *userdata)
 231 {
 232         static const char nulldevname[IFNAMSIZ];
 233         unsigned int verdict = NF_DROP;
 234         struct arphdr *arp;
 235         int hotdrop = 0;
 236         struct arpt_entry *e, *back;
 237         const char *indev, *outdev;
 238         void *table_base;
 239         struct xt_table_info *private;
 240
 241         /* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
 242         if (!pskb_may_pull((*pskb), (sizeof(struct arphdr) +
 243                                      (2 * (*pskb)->dev->addr_len) +
 244                                      (2 * sizeof(u32)))))
 245                 return NF_DROP;
 246
 247         indev = in ? in->name : nulldevname;
 248         outdev = out ? out->name : nulldevname;
 249
 250         read_lock_bh(&table->lock);
 251         private = table->private;
 252         table_base = (void *)private->entries[smp_processor_id()];
 253         e = get_entry(table_base, private->hook_entry[hook]);
 254         back = get_entry(table_base, private->underflow[hook]);
 255
 256         arp = (*pskb)->nh.arph;
 257         do {
 258                 if (arp_packet_match(arp, (*pskb)->dev, indev, outdev, &e->arp)) {
 259                         struct arpt_entry_target *t;
 260                         int hdr_len;
 261
 262                         hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
 263                                 (2 * (*pskb)->dev->addr_len);
 264                         ADD_COUNTER(e->counters, hdr_len, 1);
 265
 266                         t = arpt_get_target(e);
 267
 268                         /* Standard target? */
 269                         if (!t->u.kernel.target->target) {
 270                                 int v;
 271
 272                                 v = ((struct arpt_standard_target *)t)->verdict;
 273                                 if (v < 0) {
 274                                         /* Pop from stack? */
 275                                         if (v != ARPT_RETURN) {
 276                                                 verdict = (unsigned)(-v) - 1;
 277                                                 break;
 278                                         }
 279                                         e = back;
 280                                         back = get_entry(table_base,
 281                                                          back->comefrom);
 282                                         continue;
 283                                 }
 284                                 if (table_base + v
 285                                     != (void *)e + e->next_offset) {
 286                                         /* Save old back ptr in next entry */
 287                                         struct arpt_entry *next
 288                                                 = (void *)e + e->next_offset;
 289                                         next->comefrom =
 290                                                 (void *)back - table_base;
 291
 292                                         /* set back pointer to next entry */
 293                                         back = next;
 294                                 }
 295
 296                                 e = get_entry(table_base, v);
 297                         } else {
 298                                 /* Targets which reenter must return
 299                                  * abs. verdicts
 300                                  */
 301                                 verdict = t->u.kernel.target->target(pskb,
 302                                                                      in, out,
 303                                                                      hook,
 304                                                                      t->u.kernel.target,
 305                                                                      t->data,
 306                                                                      userdata);
 307
 308                                 /* Target might have changed stuff. */
 309                                 arp = (*pskb)->nh.arph;
 310
 311                                 if (verdict == ARPT_CONTINUE)
 312                                         e = (void *)e + e->next_offset;
 313                                 else
 314                                         /* Verdict */
 315                                         break;
 316                         }
 317                 } else {
 318                         e = (void *)e + e->next_offset;
 319                 }
 320         } while (!hotdrop);
 321         read_unlock_bh(&table->lock);
 322
 323         if (hotdrop)
 324                 return NF_DROP;
 325         else
 326                 return verdict;
 327 }
 328
 329 /* All zeroes == unconditional rule. */
 330 static inline int unconditional(const struct arpt_arp *arp)
 331 {
 332         unsigned int i;
 333
 334         for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
 335                 if (((__u32 *)arp)[i])
 336                         return 0;
 337
 338         return 1;
 339 }
 340
 341 /* Figures out from what hook each rule can be called: returns 0 if
 342  * there are loops.  Puts hook bitmask in comefrom.
 343  */
 344 static int mark_source_chains(struct xt_table_info *newinfo,
 345                               unsigned int valid_hooks, void *entry0)
 346 {
 347         unsigned int hook;
 348
 349         /* No recursion; use packet counter to save back ptrs (reset
 350          * to 0 as we leave), and comefrom to save source hook bitmask.
 351          */
 352         for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 353                 unsigned int pos = newinfo->hook_entry[hook];
 354                 struct arpt_entry *e
 355                         = (struct arpt_entry *)(entry0 + pos);
 356
 357                 if (!(valid_hooks & (1 << hook)))
 358                         continue;
 359
 360                 /* Set initial back pointer. */
 361                 e->counters.pcnt = pos;
 362
 363                 for (;;) {
 364                         struct arpt_standard_target *t
 365                                 = (void *)arpt_get_target(e);
 366
 367                         if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 368                                 printk("arptables: loop hook %u pos %u %08X.\n",
 369                                        hook, pos, e->comefrom);
 370                                 return 0;
 371                         }
 372                         e->comefrom
 373                                 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 374
 375                         /* Unconditional return/END. */
 376                         if (e->target_offset == sizeof(struct arpt_entry)
 377                             && (strcmp(t->target.u.user.name,
 378                                        ARPT_STANDARD_TARGET) == 0)
 379                             && t->verdict < 0
 380                             && unconditional(&e->arp)) {
 381                                 unsigned int oldpos, size;
 382
 383                                 /* Return: backtrack through the last
 384                                  * big jump.
 385                                  */
 386                                 do {
 387                                         e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 388                                         oldpos = pos;
 389                                         pos = e->counters.pcnt;
 390                                         e->counters.pcnt = 0;
 391
 392                                         /* We're at the start. */
 393                                         if (pos == oldpos)
 394                                                 goto next;
 395
 396                                         e = (struct arpt_entry *)
 397                                                 (entry0 + pos);
 398                                 } while (oldpos == pos + e->next_offset);
 399
 400                                 /* Move along one */
 401                                 size = e->next_offset;
 402                                 e = (struct arpt_entry *)
 403                                         (entry0 + pos + size);
 404                                 e->counters.pcnt = pos;
 405                                 pos += size;
 406                         } else {
 407                                 int newpos = t->verdict;
 408
 409                                 if (strcmp(t->target.u.user.name,
 410                                            ARPT_STANDARD_TARGET) == 0
 411                                     && newpos >= 0) {
 412                                         /* This a jump; chase it. */
 413                                         duprintf("Jump rule %u -> %u\n",
 414                                                  pos, newpos);
 415                                 } else {
 416                                         /* ... this is a fallthru */
 417                                         newpos = pos + e->next_offset;
 418                                 }
 419                                 e = (struct arpt_entry *)
 420                                         (entry0 + newpos);
 421                                 e->counters.pcnt = pos;
 422                                 pos = newpos;
 423                         }
 424                 }
 425                 next:
 426                 duprintf("Finished chain %u\n", hook);
 427         }
 428         return 1;
 429 }
 430
 431 static inline int standard_check(const struct arpt_entry_target *t,
 432                                  unsigned int max_offset)
 433 {
 434         struct arpt_standard_target *targ = (void *)t;
 435
 436         /* Check standard info. */
 437         if (t->u.target_size
 438             != ARPT_ALIGN(sizeof(struct arpt_standard_target))) {
 439                 duprintf("arpt_standard_check: target size %u != %Zu\n",
 440                          t->u.target_size,
 441                          ARPT_ALIGN(sizeof(struct arpt_standard_target)));
 442                 return 0;
 443         }
 444
 445         if (targ->verdict >= 0
 446             && targ->verdict > max_offset - sizeof(struct arpt_entry)) {
 447                 duprintf("arpt_standard_check: bad verdict (%i)\n",
 448                          targ->verdict);
 449                 return 0;
 450         }
 451
 452         if (targ->verdict < -NF_MAX_VERDICT - 1) {
 453                 duprintf("arpt_standard_check: bad negative verdict (%i)\n",
 454                          targ->verdict);
 455                 return 0;
 456         }
 457         return 1;
 458 }
 459
 460 static struct arpt_target arpt_standard_target;
 461
 462 static inline int check_entry(struct arpt_entry *e, const char *name, unsigned int size,
 463                               unsigned int *i)
 464 {
 465         struct arpt_entry_target *t;
 466         struct arpt_target *target;
 467         int ret;
 468
 469         if (!arp_checkentry(&e->arp)) {
 470                 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 471                 return -EINVAL;
 472         }
 473
 474         t = arpt_get_target(e);
 475         target = try_then_request_module(xt_find_target(NF_ARP, t->u.user.name,
 476                                                         t->u.user.revision),
 477                                          "arpt_%s", t->u.user.name);
 478         if (IS_ERR(target) || !target) {
 479                 duprintf("check_entry: `%s' not found\n", t->u.user.name);
 480                 ret = target ? PTR_ERR(target) : -ENOENT;
 481                 goto out;
 482         }
 483         t->u.kernel.target = target;
 484
 485         ret = xt_check_target(target, NF_ARP, t->u.target_size - sizeof(*t),
 486                               name, e->comefrom, 0, 0);
 487         if (ret)
 488                 goto err;
 489
 490         if (t->u.kernel.target == &arpt_standard_target) {
 491                 if (!standard_check(t, size)) {
 492                         ret = -EINVAL;
 493                         goto out;
 494                 }
 495         } else if (t->u.kernel.target->checkentry
 496                    && !t->u.kernel.target->checkentry(name, e, target, t->data,
 497                                                       t->u.target_size
 498                                                       - sizeof(*t),
 499                                                       e->comefrom)) {
 500                 duprintf("arp_tables: check failed for `%s'.\n",
 501                          t->u.kernel.target->name);
 502                 ret = -EINVAL;
 503                 goto err;
 504         }
 505
 506         (*i)++;
 507         return 0;
 508 err:
 509         module_put(t->u.kernel.target->me);
 510 out:
 511         return ret;
 512 }
 513
 514 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 515                                              struct xt_table_info *newinfo,
 516                                              unsigned char *base,
 517                                              unsigned char *limit,
 518                                              const unsigned int *hook_entries,
 519                                              const unsigned int *underflows,
 520                                              unsigned int *i)
 521 {
 522         unsigned int h;
 523
 524         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 525             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 526                 duprintf("Bad offset %p\n", e);
 527                 return -EINVAL;
 528         }
 529
 530         if (e->next_offset
 531             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 532                 duprintf("checking: element %p size %u\n",
 533                          e, e->next_offset);
 534                 return -EINVAL;
 535         }
 536
 537         /* Check hooks & underflows */
 538         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 539                 if ((unsigned char *)e - base == hook_entries[h])
 540                         newinfo->hook_entry[h] = hook_entries[h];
 541                 if ((unsigned char *)e - base == underflows[h])
 542                         newinfo->underflow[h] = underflows[h];
 543         }
 544
 545         /* FIXME: underflows must be unconditional, standard verdicts
 546            < 0 (not ARPT_RETURN). --RR */
 547
 548         /* Clear counters and comefrom */
 549         e->counters = ((struct xt_counters) { 0, 0 });
 550         e->comefrom = 0;
 551
 552         (*i)++;
 553         return 0;
 554 }
 555
 556 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 557 {
 558         struct arpt_entry_target *t;
 559
 560         if (i && (*i)-- == 0)
 561                 return 1;
 562
 563         t = arpt_get_target(e);
 564         if (t->u.kernel.target->destroy)
 565                 t->u.kernel.target->destroy(t->u.kernel.target, t->data,
 566                                             t->u.target_size - sizeof(*t));
 567         module_put(t->u.kernel.target->me);
 568         return 0;
 569 }
 570
 571 /* Checks and translates the user-supplied table segment (held in
 572  * newinfo).
 573  */
 574 static int translate_table(const char *name,
 575                            unsigned int valid_hooks,
 576                            struct xt_table_info *newinfo,
 577                            void *entry0,
 578                            unsigned int size,
 579                            unsigned int number,
 580                            const unsigned int *hook_entries,
 581                            const unsigned int *underflows)
 582 {
 583         unsigned int i;
 584         int ret;
 585
 586         newinfo->size = size;
 587         newinfo->number = number;
 588
 589         /* Init all hooks to impossible value. */
 590         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 591                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 592                 newinfo->underflow[i] = 0xFFFFFFFF;
 593         }
 594
 595         duprintf("translate_table: size %u\n", newinfo->size);
 596         i = 0;
 597
 598         /* Walk through entries, checking offsets. */
 599         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 600                                  check_entry_size_and_hooks,
 601                                  newinfo,
 602                                  entry0,
 603                                  entry0 + size,
 604                                  hook_entries, underflows, &i);
 605         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 606         if (ret != 0)
 607                 return ret;
 608
 609         if (i != number) {
 610                 duprintf("translate_table: %u not %u entries\n",
 611                          i, number);
 612                 return -EINVAL;
 613         }
 614
 615         /* Check hooks all assigned */
 616         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 617                 /* Only hooks which are valid */
 618                 if (!(valid_hooks & (1 << i)))
 619                         continue;
 620                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 621                         duprintf("Invalid hook entry %u %u\n",
 622                                  i, hook_entries[i]);
 623                         return -EINVAL;
 624                 }
 625                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 626                         duprintf("Invalid underflow %u %u\n",
 627                                  i, underflows[i]);
 628                         return -EINVAL;
 629                 }
 630         }
 631
 632         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 633                 duprintf("Looping hook\n");
 634                 return -ELOOP;
 635         }
 636
 637         /* Finally, each sanity check must pass */
 638         i = 0;
 639         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 640                                  check_entry, name, size, &i);
 641
 642         if (ret != 0) {
 643                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 644                                    cleanup_entry, &i);
 645                 return ret;
 646         }
 647
 648         /* And one copy for every other CPU */
 649         for_each_possible_cpu(i) {
 650                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 651                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 652         }
 653
 654         return ret;
 655 }
 656
 657 /* Gets counters. */
 658 static inline int add_entry_to_counter(const struct arpt_entry *e,
 659                                        struct xt_counters total[],
 660                                        unsigned int *i)
 661 {
 662         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 663
 664         (*i)++;
 665         return 0;
 666 }
 667
 668 static inline int set_entry_to_counter(const struct arpt_entry *e,
 669                                        struct xt_counters total[],
 670                                        unsigned int *i)
 671 {
 672         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 673
 674         (*i)++;
 675         return 0;
 676 }
 677
 678 static void get_counters(const struct xt_table_info *t,
 679                          struct xt_counters counters[])
 680 {
 681         unsigned int cpu;
 682         unsigned int i;
 683         unsigned int curcpu;
 684
 685         /* Instead of clearing (by a previous call to memset())
 686          * the counters and using adds, we set the counters
 687          * with data used by 'current' CPU
 688          * We dont care about preemption here.
 689          */
 690         curcpu = raw_smp_processor_id();
 691
 692         i = 0;
 693         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 694                            t->size,
 695                            set_entry_to_counter,
 696                            counters,
 697                            &i);
 698
 699         for_each_possible_cpu(cpu) {
 700                 if (cpu == curcpu)
 701                         continue;
 702                 i = 0;
 703                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 704                                    t->size,
 705                                    add_entry_to_counter,
 706                                    counters,
 707                                    &i);
 708         }
 709 }
 710
 711 static int copy_entries_to_user(unsigned int total_size,
 712                                 struct arpt_table *table,
 713                                 void __user *userptr)
 714 {
 715         unsigned int off, num, countersize;
 716         struct arpt_entry *e;
 717         struct xt_counters *counters;
 718         struct xt_table_info *private = table->private;
 719         int ret = 0;
 720         void *loc_cpu_entry;
 721
 722         /* We need atomic snapshot of counters: rest doesn't change
 723          * (other than comefrom, which userspace doesn't care
 724          * about).
 725          */
 726         countersize = sizeof(struct xt_counters) * private->number;
 727         counters = vmalloc_node(countersize, numa_node_id());
 728
 729         if (counters == NULL)
 730                 return -ENOMEM;
 731
 732         /* First, sum counters... */
 733         write_lock_bh(&table->lock);
 734         get_counters(private, counters);
 735         write_unlock_bh(&table->lock);
 736
 737         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 738         /* ... then copy entire thing ... */
 739         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 740                 ret = -EFAULT;
 741                 goto free_counters;
 742         }
 743
 744         /* FIXME: use iterator macros --RR */
 745         /* ... then go back and fix counters and names */
 746         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 747                 struct arpt_entry_target *t;
 748
 749                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 750                 if (copy_to_user(userptr + off
 751                                  + offsetof(struct arpt_entry, counters),
 752                                  &counters[num],
 753                                  sizeof(counters[num])) != 0) {
 754                         ret = -EFAULT;
 755                         goto free_counters;
 756                 }
 757
 758                 t = arpt_get_target(e);
 759                 if (copy_to_user(userptr + off + e->target_offset
 760                                  + offsetof(struct arpt_entry_target,
 761                                             u.user.name),
 762                                  t->u.kernel.target->name,
 763                                  strlen(t->u.kernel.target->name)+1) != 0) {
 764                         ret = -EFAULT;
 765                         goto free_counters;
 766                 }
 767         }
 768
 769  free_counters:
 770         vfree(counters);
 771         return ret;
 772 }
 773
 774 static int get_entries(const struct arpt_get_entries *entries,
 775                        struct arpt_get_entries __user *uptr)
 776 {
 777         int ret;
 778         struct arpt_table *t;
 779
 780         t = xt_find_table_lock(NF_ARP, entries->name);
 781         if (t && !IS_ERR(t)) {
 782                 struct xt_table_info *private = t->private;
 783                 duprintf("t->private->number = %u\n",
 784                          private->number);
 785                 if (entries->size == private->size)
 786                         ret = copy_entries_to_user(private->size,
 787                                                    t, uptr->entrytable);
 788                 else {
 789                         duprintf("get_entries: I've got %u not %u!\n",
 790                                  private->size, entries->size);
 791                         ret = -EINVAL;
 792                 }
 793                 module_put(t->me);
 794                 xt_table_unlock(t);
 795         } else
 796                 ret = t ? PTR_ERR(t) : -ENOENT;
 797
 798         return ret;
 799 }
 800
 801 static int do_replace(void __user *user, unsigned int len)
 802 {
 803         int ret;
 804         struct arpt_replace tmp;
 805         struct arpt_table *t;
 806         struct xt_table_info *newinfo, *oldinfo;
 807         struct xt_counters *counters;
 808         void *loc_cpu_entry, *loc_cpu_old_entry;
 809
 810         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 811                 return -EFAULT;
 812
 813         /* Hack: Causes ipchains to give correct error msg --RR */
 814         if (len != sizeof(tmp) + tmp.size)
 815                 return -ENOPROTOOPT;
 816
 817         /* overflow check */
 818         if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
 819                         SMP_CACHE_BYTES)
 820                 return -ENOMEM;
 821         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 822                 return -ENOMEM;
 823
 824         newinfo = xt_alloc_table_info(tmp.size);
 825         if (!newinfo)
 826                 return -ENOMEM;
 827
 828         /* choose the copy that is on our node/cpu */
 829         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
 830         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 831                            tmp.size) != 0) {
 832                 ret = -EFAULT;
 833                 goto free_newinfo;
 834         }
 835
 836         counters = vmalloc(tmp.num_counters * sizeof(struct xt_counters));
 837         if (!counters) {
 838                 ret = -ENOMEM;
 839                 goto free_newinfo;
 840         }
 841
 842         ret = translate_table(tmp.name, tmp.valid_hooks,
 843                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
 844                               tmp.hook_entry, tmp.underflow);
 845         if (ret != 0)
 846                 goto free_newinfo_counters;
 847
 848         duprintf("arp_tables: Translated table\n");
 849
 850         t = try_then_request_module(xt_find_table_lock(NF_ARP, tmp.name),
 851                                     "arptable_%s", tmp.name);
 852         if (!t || IS_ERR(t)) {
 853                 ret = t ? PTR_ERR(t) : -ENOENT;
 854                 goto free_newinfo_counters_untrans;
 855         }
 856
 857         /* You lied! */
 858         if (tmp.valid_hooks != t->valid_hooks) {
 859                 duprintf("Valid hook crap: %08X vs %08X\n",
 860                          tmp.valid_hooks, t->valid_hooks);
 861                 ret = -EINVAL;
 862                 goto put_module;
 863         }
 864
 865         oldinfo = xt_replace_table(t, tmp.num_counters, newinfo, &ret);
 866         if (!oldinfo)
 867                 goto put_module;
 868
 869         /* Update module usage count based on number of rules */
 870         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
 871                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
 872         if ((oldinfo->number > oldinfo->initial_entries) ||
 873             (newinfo->number <= oldinfo->initial_entries))
 874                 module_put(t->me);
 875         if ((oldinfo->number > oldinfo->initial_entries) &&
 876             (newinfo->number <= oldinfo->initial_entries))
 877                 module_put(t->me);
 878
 879         /* Get the old counters. */
 880         get_counters(oldinfo, counters);
 881         /* Decrease module usage counts and free resource */
 882         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
 883         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,NULL);
 884
 885         xt_free_table_info(oldinfo);
 886         if (copy_to_user(tmp.counters, counters,
 887                          sizeof(struct xt_counters) * tmp.num_counters) != 0)
 888                 ret = -EFAULT;
 889         vfree(counters);
 890         xt_table_unlock(t);
 891         return ret;
 892
 893  put_module:
 894         module_put(t->me);
 895         xt_table_unlock(t);
 896  free_newinfo_counters_untrans:
 897         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
 898  free_newinfo_counters:
 899         vfree(counters);
 900  free_newinfo:
 901         xt_free_table_info(newinfo);
 902         return ret;
 903 }
 904
 905 /* We're lazy, and add to the first CPU; overflow works its fey magic
 906  * and everything is OK.
 907  */
 908 static inline int add_counter_to_entry(struct arpt_entry *e,
 909                                        const struct xt_counters addme[],
 910                                        unsigned int *i)
 911 {
 912
 913         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
 914
 915         (*i)++;
 916         return 0;
 917 }
 918
 919 static int do_add_counters(void __user *user, unsigned int len)
 920 {
 921         unsigned int i;
 922         struct xt_counters_info tmp, *paddc;
 923         struct arpt_table *t;
 924         struct xt_table_info *private;
 925         int ret = 0;
 926         void *loc_cpu_entry;
 927
 928         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 929                 return -EFAULT;
 930
 931         if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct xt_counters))
 932                 return -EINVAL;
 933
 934         paddc = vmalloc(len);
 935         if (!paddc)
 936                 return -ENOMEM;
 937
 938         if (copy_from_user(paddc, user, len) != 0) {
 939                 ret = -EFAULT;
 940                 goto free;
 941         }
 942
 943         t = xt_find_table_lock(NF_ARP, tmp.name);
 944         if (!t || IS_ERR(t)) {
 945                 ret = t ? PTR_ERR(t) : -ENOENT;
 946                 goto free;
 947         }
 948
 949         write_lock_bh(&t->lock);
 950         private = t->private;
 951         if (private->number != tmp.num_counters) {
 952                 ret = -EINVAL;
 953                 goto unlock_up_free;
 954         }
 955
 956         i = 0;
 957         /* Choose the copy that is on our node */
 958         loc_cpu_entry = private->entries[smp_processor_id()];
 959         ARPT_ENTRY_ITERATE(loc_cpu_entry,
 960                            private->size,
 961                            add_counter_to_entry,
 962                            paddc->counters,
 963                            &i);
 964  unlock_up_free:
 965         write_unlock_bh(&t->lock);
 966         xt_table_unlock(t);
 967         module_put(t->me);
 968  free:
 969         vfree(paddc);
 970
 971         return ret;
 972 }
 973
 974 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 975 {
 976         int ret;
 977
 978         if (!capable(CAP_NET_ADMIN))
 979                 return -EPERM;
 980
 981         switch (cmd) {
 982         case ARPT_SO_SET_REPLACE:
 983                 ret = do_replace(user, len);
 984                 break;
 985
 986         case ARPT_SO_SET_ADD_COUNTERS:
 987                 ret = do_add_counters(user, len);
 988                 break;
 989
 990         default:
 991                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
 992                 ret = -EINVAL;
 993         }
 994
 995         return ret;
 996 }
 997
 998 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
 999 {
1000         int ret;
1001
1002         if (!capable(CAP_NET_ADMIN))
1003                 return -EPERM;
1004
1005         switch (cmd) {
1006         case ARPT_SO_GET_INFO: {
1007                 char name[ARPT_TABLE_MAXNAMELEN];
1008                 struct arpt_table *t;
1009
1010                 if (*len != sizeof(struct arpt_getinfo)) {
1011                         duprintf("length %u != %Zu\n", *len,
1012                                  sizeof(struct arpt_getinfo));
1013                         ret = -EINVAL;
1014                         break;
1015                 }
1016
1017                 if (copy_from_user(name, user, sizeof(name)) != 0) {
1018                         ret = -EFAULT;
1019                         break;
1020                 }
1021                 name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
1022
1023                 t = try_then_request_module(xt_find_table_lock(NF_ARP, name),
1024                                             "arptable_%s", name);
1025                 if (t && !IS_ERR(t)) {
1026                         struct arpt_getinfo info;
1027                         struct xt_table_info *private = t->private;
1028
1029                         info.valid_hooks = t->valid_hooks;
1030                         memcpy(info.hook_entry, private->hook_entry,
1031                                sizeof(info.hook_entry));
1032                         memcpy(info.underflow, private->underflow,
1033                                sizeof(info.underflow));
1034                         info.num_entries = private->number;
1035                         info.size = private->size;
1036                         strcpy(info.name, name);
1037
1038                         if (copy_to_user(user, &info, *len) != 0)
1039                                 ret = -EFAULT;
1040                         else
1041                                 ret = 0;
1042                         xt_table_unlock(t);
1043                         module_put(t->me);
1044                 } else
1045                         ret = t ? PTR_ERR(t) : -ENOENT;
1046         }
1047         break;
1048
1049         case ARPT_SO_GET_ENTRIES: {
1050                 struct arpt_get_entries get;
1051
1052                 if (*len < sizeof(get)) {
1053                         duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1054                         ret = -EINVAL;
1055                 } else if (copy_from_user(&get, user, sizeof(get)) != 0) {
1056                         ret = -EFAULT;
1057                 } else if (*len != sizeof(struct arpt_get_entries) + get.size) {
1058                         duprintf("get_entries: %u != %Zu\n", *len,
1059                                  sizeof(struct arpt_get_entries) + get.size);
1060                         ret = -EINVAL;
1061                 } else
1062                         ret = get_entries(&get, user);
1063                 break;
1064         }
1065
1066         case ARPT_SO_GET_REVISION_TARGET: {
1067                 struct xt_get_revision rev;
1068
1069                 if (*len != sizeof(rev)) {
1070                         ret = -EINVAL;
1071                         break;
1072                 }
1073                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1074                         ret = -EFAULT;
1075                         break;
1076                 }
1077
1078                 try_then_request_module(xt_find_revision(NF_ARP, rev.name,
1079                                                          rev.revision, 1, &ret),
1080                                         "arpt_%s", rev.name);
1081                 break;
1082         }
1083
1084         default:
1085                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1086                 ret = -EINVAL;
1087         }
1088
1089         return ret;
1090 }
1091
1092 int arpt_register_table(struct arpt_table *table,
1093                         const struct arpt_replace *repl)
1094 {
1095         int ret;
1096         struct xt_table_info *newinfo;
1097         static struct xt_table_info bootstrap
1098                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1099         void *loc_cpu_entry;
1100
1101         newinfo = xt_alloc_table_info(repl->size);
1102         if (!newinfo) {
1103                 ret = -ENOMEM;
1104                 return ret;
1105         }
1106
1107         /* choose the copy on our node/cpu */
1108         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1109         memcpy(loc_cpu_entry, repl->entries, repl->size);
1110
1111         ret = translate_table(table->name, table->valid_hooks,
1112                               newinfo, loc_cpu_entry, repl->size,
1113                               repl->num_entries,
1114                               repl->hook_entry,
1115                               repl->underflow);
1116
1117         duprintf("arpt_register_table: translate table gives %d\n", ret);
1118         if (ret != 0) {
1119                 xt_free_table_info(newinfo);
1120                 return ret;
1121         }
1122
1123         ret = xt_register_table(table, &bootstrap, newinfo);
1124         if (ret != 0) {
1125                 xt_free_table_info(newinfo);
1126                 return ret;
1127         }
1128
1129         return 0;
1130 }
1131
1132 void arpt_unregister_table(struct arpt_table *table)
1133 {
1134         struct xt_table_info *private;
1135         void *loc_cpu_entry;
1136
1137         private = xt_unregister_table(table);
1138
1139         /* Decrease module usage counts and free resources */
1140         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1141         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1142                            cleanup_entry, NULL);
1143         xt_free_table_info(private);
1144 }
1145
1146 /* The built-in targets: standard (NULL) and error. */
1147 static struct arpt_target arpt_standard_target = {
1148         .name           = ARPT_STANDARD_TARGET,
1149         .targetsize     = sizeof(int),
1150         .family         = NF_ARP,
1151 };
1152
1153 static struct arpt_target arpt_error_target = {
1154         .name           = ARPT_ERROR_TARGET,
1155         .target         = arpt_error,
1156         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1157         .family         = NF_ARP,
1158 };
1159
1160 static struct nf_sockopt_ops arpt_sockopts = {
1161         .pf             = PF_INET,
1162         .set_optmin     = ARPT_BASE_CTL,
1163         .set_optmax     = ARPT_SO_SET_MAX+1,
1164         .set            = do_arpt_set_ctl,
1165         .get_optmin     = ARPT_BASE_CTL,
1166         .get_optmax     = ARPT_SO_GET_MAX+1,
1167         .get            = do_arpt_get_ctl,
1168 };
1169
1170 static int __init arp_tables_init(void)
1171 {
1172         int ret;
1173
1174         ret = xt_proto_init(NF_ARP);
1175         if (ret < 0)
1176                 goto err1;
1177
1178         /* Noone else will be downing sem now, so we won't sleep */
1179         ret = xt_register_target(&arpt_standard_target);
1180         if (ret < 0)
1181                 goto err2;
1182         ret = xt_register_target(&arpt_error_target);
1183         if (ret < 0)
1184                 goto err3;
1185
1186         /* Register setsockopt */
1187         ret = nf_register_sockopt(&arpt_sockopts);
1188         if (ret < 0)
1189                 goto err4;
1190
1191         printk("arp_tables: (C) 2002 David S. Miller\n");
1192         return 0;
1193
1194 err4:
1195         xt_unregister_target(&arpt_error_target);
1196 err3:
1197         xt_unregister_target(&arpt_standard_target);
1198 err2:
1199         xt_proto_fini(NF_ARP);
1200 err1:
1201         return ret;
1202 }
1203
1204 static void __exit arp_tables_fini(void)
1205 {
1206         nf_unregister_sockopt(&arpt_sockopts);
1207         xt_proto_fini(NF_ARP);
1208 }
1209
1210 EXPORT_SYMBOL(arpt_register_table);
1211 EXPORT_SYMBOL(arpt_unregister_table);
1212 EXPORT_SYMBOL(arpt_do_table);
1213
1214 module_init(arp_tables_init);
1215 module_exit(arp_tables_fini);