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