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

   1 /*
   2  * Packet matching code for ARP packets.
   3  *
   4  * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5  *
   6  * Some ARP specific bits are:
   7  *
   8  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9  *
  10  */
  11
  12 #include <linux/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         ret = xt_check_target(target, NF_ARP, t->u.target_size - sizeof(*t),
 484                               name, e->comefrom, 0, 0);
 485         if (ret)
 486                 goto err;
 487
 488         if (t->u.kernel.target == &arpt_standard_target) {
 489                 if (!standard_check(t, size)) {
 490                         ret = -EINVAL;
 491                         goto out;
 492                 }
 493         } else if (t->u.kernel.target->checkentry
 494                    && !t->u.kernel.target->checkentry(name, e, t->data,
 495                                                       t->u.target_size
 496                                                       - sizeof(*t),
 497                                                       e->comefrom)) {
 498                 duprintf("arp_tables: check failed for `%s'.\n",
 499                          t->u.kernel.target->name);
 500                 ret = -EINVAL;
 501                 goto err;
 502         }
 503
 504         (*i)++;
 505         return 0;
 506 err:
 507         module_put(t->u.kernel.target->me);
 508 out:
 509         return ret;
 510 }
 511
 512 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 513                                              struct xt_table_info *newinfo,
 514                                              unsigned char *base,
 515                                              unsigned char *limit,
 516                                              const unsigned int *hook_entries,
 517                                              const unsigned int *underflows,
 518                                              unsigned int *i)
 519 {
 520         unsigned int h;
 521
 522         if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
 523             || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 524                 duprintf("Bad offset %p\n", e);
 525                 return -EINVAL;
 526         }
 527
 528         if (e->next_offset
 529             < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
 530                 duprintf("checking: element %p size %u\n",
 531                          e, e->next_offset);
 532                 return -EINVAL;
 533         }
 534
 535         /* Check hooks & underflows */
 536         for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 537                 if ((unsigned char *)e - base == hook_entries[h])
 538                         newinfo->hook_entry[h] = hook_entries[h];
 539                 if ((unsigned char *)e - base == underflows[h])
 540                         newinfo->underflow[h] = underflows[h];
 541         }
 542
 543         /* FIXME: underflows must be unconditional, standard verdicts
 544            < 0 (not ARPT_RETURN). --RR */
 545
 546         /* Clear counters and comefrom */
 547         e->counters = ((struct xt_counters) { 0, 0 });
 548         e->comefrom = 0;
 549
 550         (*i)++;
 551         return 0;
 552 }
 553
 554 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
 555 {
 556         struct arpt_entry_target *t;
 557
 558         if (i && (*i)-- == 0)
 559                 return 1;
 560
 561         t = arpt_get_target(e);
 562         if (t->u.kernel.target->destroy)
 563                 t->u.kernel.target->destroy(t->data,
 564                                             t->u.target_size - sizeof(*t));
 565         module_put(t->u.kernel.target->me);
 566         return 0;
 567 }
 568
 569 /* Checks and translates the user-supplied table segment (held in
 570  * newinfo).
 571  */
 572 static int translate_table(const char *name,
 573                            unsigned int valid_hooks,
 574                            struct xt_table_info *newinfo,
 575                            void *entry0,
 576                            unsigned int size,
 577                            unsigned int number,
 578                            const unsigned int *hook_entries,
 579                            const unsigned int *underflows)
 580 {
 581         unsigned int i;
 582         int ret;
 583
 584         newinfo->size = size;
 585         newinfo->number = number;
 586
 587         /* Init all hooks to impossible value. */
 588         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 589                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 590                 newinfo->underflow[i] = 0xFFFFFFFF;
 591         }
 592
 593         duprintf("translate_table: size %u\n", newinfo->size);
 594         i = 0;
 595
 596         /* Walk through entries, checking offsets. */
 597         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 598                                  check_entry_size_and_hooks,
 599                                  newinfo,
 600                                  entry0,
 601                                  entry0 + size,
 602                                  hook_entries, underflows, &i);
 603         duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 604         if (ret != 0)
 605                 return ret;
 606
 607         if (i != number) {
 608                 duprintf("translate_table: %u not %u entries\n",
 609                          i, number);
 610                 return -EINVAL;
 611         }
 612
 613         /* Check hooks all assigned */
 614         for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 615                 /* Only hooks which are valid */
 616                 if (!(valid_hooks & (1 << i)))
 617                         continue;
 618                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 619                         duprintf("Invalid hook entry %u %u\n",
 620                                  i, hook_entries[i]);
 621                         return -EINVAL;
 622                 }
 623                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
 624                         duprintf("Invalid underflow %u %u\n",
 625                                  i, underflows[i]);
 626                         return -EINVAL;
 627                 }
 628         }
 629
 630         if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
 631                 duprintf("Looping hook\n");
 632                 return -ELOOP;
 633         }
 634
 635         /* Finally, each sanity check must pass */
 636         i = 0;
 637         ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 638                                  check_entry, name, size, &i);
 639
 640         if (ret != 0) {
 641                 ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 642                                    cleanup_entry, &i);
 643                 return ret;
 644         }
 645
 646         /* And one copy for every other CPU */
 647         for_each_cpu(i) {
 648                 if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 649                         memcpy(newinfo->entries[i], entry0, newinfo->size);
 650         }
 651
 652         return ret;
 653 }
 654
 655 /* Gets counters. */
 656 static inline int add_entry_to_counter(const struct arpt_entry *e,
 657                                        struct xt_counters total[],
 658                                        unsigned int *i)
 659 {
 660         ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 661
 662         (*i)++;
 663         return 0;
 664 }
 665
 666 static inline int set_entry_to_counter(const struct arpt_entry *e,
 667                                        struct xt_counters total[],
 668                                        unsigned int *i)
 669 {
 670         SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 671
 672         (*i)++;
 673         return 0;
 674 }
 675
 676 static void get_counters(const struct xt_table_info *t,
 677                          struct xt_counters counters[])
 678 {
 679         unsigned int cpu;
 680         unsigned int i;
 681         unsigned int curcpu;
 682
 683         /* Instead of clearing (by a previous call to memset())
 684          * the counters and using adds, we set the counters
 685          * with data used by 'current' CPU
 686          * We dont care about preemption here.
 687          */
 688         curcpu = raw_smp_processor_id();
 689
 690         i = 0;
 691         ARPT_ENTRY_ITERATE(t->entries[curcpu],
 692                            t->size,
 693                            set_entry_to_counter,
 694                            counters,
 695                            &i);
 696
 697         for_each_cpu(cpu) {
 698                 if (cpu == curcpu)
 699                         continue;
 700                 i = 0;
 701                 ARPT_ENTRY_ITERATE(t->entries[cpu],
 702                                    t->size,
 703                                    add_entry_to_counter,
 704                                    counters,
 705                                    &i);
 706         }
 707 }
 708
 709 static int copy_entries_to_user(unsigned int total_size,
 710                                 struct arpt_table *table,
 711                                 void __user *userptr)
 712 {
 713         unsigned int off, num, countersize;
 714         struct arpt_entry *e;
 715         struct xt_counters *counters;
 716         struct xt_table_info *private = table->private;
 717         int ret = 0;
 718         void *loc_cpu_entry;
 719
 720         /* We need atomic snapshot of counters: rest doesn't change
 721          * (other than comefrom, which userspace doesn't care
 722          * about).
 723          */
 724         countersize = sizeof(struct xt_counters) * private->number;
 725         counters = vmalloc_node(countersize, numa_node_id());
 726
 727         if (counters == NULL)
 728                 return -ENOMEM;
 729
 730         /* First, sum counters... */
 731         write_lock_bh(&table->lock);
 732         get_counters(private, counters);
 733         write_unlock_bh(&table->lock);
 734
 735         loc_cpu_entry = private->entries[raw_smp_processor_id()];
 736         /* ... then copy entire thing ... */
 737         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 738                 ret = -EFAULT;
 739                 goto free_counters;
 740         }
 741
 742         /* FIXME: use iterator macros --RR */
 743         /* ... then go back and fix counters and names */
 744         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 745                 struct arpt_entry_target *t;
 746
 747                 e = (struct arpt_entry *)(loc_cpu_entry + off);
 748                 if (copy_to_user(userptr + off
 749                                  + offsetof(struct arpt_entry, counters),
 750                                  &counters[num],
 751                                  sizeof(counters[num])) != 0) {
 752                         ret = -EFAULT;
 753                         goto free_counters;
 754                 }
 755
 756                 t = arpt_get_target(e);
 757                 if (copy_to_user(userptr + off + e->target_offset
 758                                  + offsetof(struct arpt_entry_target,
 759                                             u.user.name),
 760                                  t->u.kernel.target->name,
 761                                  strlen(t->u.kernel.target->name)+1) != 0) {
 762                         ret = -EFAULT;
 763                         goto free_counters;
 764                 }
 765         }
 766
 767  free_counters:
 768         vfree(counters);
 769         return ret;
 770 }
 771
 772 static int get_entries(const struct arpt_get_entries *entries,
 773                        struct arpt_get_entries __user *uptr)
 774 {
 775         int ret;
 776         struct arpt_table *t;
 777
 778         t = xt_find_table_lock(NF_ARP, entries->name);
 779         if (t && !IS_ERR(t)) {
 780                 struct xt_table_info *private = t->private;
 781                 duprintf("t->private->number = %u\n",
 782                          private->number);
 783                 if (entries->size == private->size)
 784                         ret = copy_entries_to_user(private->size,
 785                                                    t, uptr->entrytable);
 786                 else {
 787                         duprintf("get_entries: I've got %u not %u!\n",
 788                                  private->size, entries->size);
 789                         ret = -EINVAL;
 790                 }
 791                 module_put(t->me);
 792                 xt_table_unlock(t);
 793         } else
 794                 ret = t ? PTR_ERR(t) : -ENOENT;
 795
 796         return ret;
 797 }
 798
 799 static int do_replace(void __user *user, unsigned int len)
 800 {
 801         int ret;
 802         struct arpt_replace tmp;
 803         struct arpt_table *t;
 804         struct xt_table_info *newinfo, *oldinfo;
 805         struct xt_counters *counters;
 806         void *loc_cpu_entry, *loc_cpu_old_entry;
 807
 808         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 809                 return -EFAULT;
 810
 811         /* Hack: Causes ipchains to give correct error msg --RR */
 812         if (len != sizeof(tmp) + tmp.size)
 813                 return -ENOPROTOOPT;
 814
 815         /* overflow check */
 816         if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
 817                         SMP_CACHE_BYTES)
 818                 return -ENOMEM;
 819         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 820                 return -ENOMEM;
 821
 822         newinfo = xt_alloc_table_info(tmp.size);
 823         if (!newinfo)
 824                 return -ENOMEM;
 825
 826         /* choose the copy that is on our node/cpu */
 827         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
 828         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
 829                            tmp.size) != 0) {
 830                 ret = -EFAULT;
 831                 goto free_newinfo;
 832         }
 833
 834         counters = vmalloc(tmp.num_counters * sizeof(struct xt_counters));
 835         if (!counters) {
 836                 ret = -ENOMEM;
 837                 goto free_newinfo;
 838         }
 839
 840         ret = translate_table(tmp.name, tmp.valid_hooks,
 841                               newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
 842                               tmp.hook_entry, tmp.underflow);
 843         if (ret != 0)
 844                 goto free_newinfo_counters;
 845
 846         duprintf("arp_tables: Translated table\n");
 847
 848         t = try_then_request_module(xt_find_table_lock(NF_ARP, tmp.name),
 849                                     "arptable_%s", tmp.name);
 850         if (!t || IS_ERR(t)) {
 851                 ret = t ? PTR_ERR(t) : -ENOENT;
 852                 goto free_newinfo_counters_untrans;
 853         }
 854
 855         /* You lied! */
 856         if (tmp.valid_hooks != t->valid_hooks) {
 857                 duprintf("Valid hook crap: %08X vs %08X\n",
 858                          tmp.valid_hooks, t->valid_hooks);
 859                 ret = -EINVAL;
 860                 goto put_module;
 861         }
 862
 863         oldinfo = xt_replace_table(t, tmp.num_counters, newinfo, &ret);
 864         if (!oldinfo)
 865                 goto put_module;
 866
 867         /* Update module usage count based on number of rules */
 868         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
 869                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
 870         if ((oldinfo->number > oldinfo->initial_entries) ||
 871             (newinfo->number <= oldinfo->initial_entries))
 872                 module_put(t->me);
 873         if ((oldinfo->number > oldinfo->initial_entries) &&
 874             (newinfo->number <= oldinfo->initial_entries))
 875                 module_put(t->me);
 876
 877         /* Get the old counters. */
 878         get_counters(oldinfo, counters);
 879         /* Decrease module usage counts and free resource */
 880         loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
 881         ARPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,NULL);
 882
 883         xt_free_table_info(oldinfo);
 884         if (copy_to_user(tmp.counters, counters,
 885                          sizeof(struct xt_counters) * tmp.num_counters) != 0)
 886                 ret = -EFAULT;
 887         vfree(counters);
 888         xt_table_unlock(t);
 889         return ret;
 890
 891  put_module:
 892         module_put(t->me);
 893         xt_table_unlock(t);
 894  free_newinfo_counters_untrans:
 895         ARPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry, NULL);
 896  free_newinfo_counters:
 897         vfree(counters);
 898  free_newinfo:
 899         xt_free_table_info(newinfo);
 900         return ret;
 901 }
 902
 903 /* We're lazy, and add to the first CPU; overflow works its fey magic
 904  * and everything is OK.
 905  */
 906 static inline int add_counter_to_entry(struct arpt_entry *e,
 907                                        const struct xt_counters addme[],
 908                                        unsigned int *i)
 909 {
 910
 911         ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
 912
 913         (*i)++;
 914         return 0;
 915 }
 916
 917 static int do_add_counters(void __user *user, unsigned int len)
 918 {
 919         unsigned int i;
 920         struct xt_counters_info tmp, *paddc;
 921         struct arpt_table *t;
 922         struct xt_table_info *private;
 923         int ret = 0;
 924         void *loc_cpu_entry;
 925
 926         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
 927                 return -EFAULT;
 928
 929         if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct xt_counters))
 930                 return -EINVAL;
 931
 932         paddc = vmalloc(len);
 933         if (!paddc)
 934                 return -ENOMEM;
 935
 936         if (copy_from_user(paddc, user, len) != 0) {
 937                 ret = -EFAULT;
 938                 goto free;
 939         }
 940
 941         t = xt_find_table_lock(NF_ARP, tmp.name);
 942         if (!t || IS_ERR(t)) {
 943                 ret = t ? PTR_ERR(t) : -ENOENT;
 944                 goto free;
 945         }
 946
 947         write_lock_bh(&t->lock);
 948         private = t->private;
 949         if (private->number != paddc->num_counters) {
 950                 ret = -EINVAL;
 951                 goto unlock_up_free;
 952         }
 953
 954         i = 0;
 955         /* Choose the copy that is on our node */
 956         loc_cpu_entry = private->entries[smp_processor_id()];
 957         ARPT_ENTRY_ITERATE(loc_cpu_entry,
 958                            private->size,
 959                            add_counter_to_entry,
 960                            paddc->counters,
 961                            &i);
 962  unlock_up_free:
 963         write_unlock_bh(&t->lock);
 964         xt_table_unlock(t);
 965         module_put(t->me);
 966  free:
 967         vfree(paddc);
 968
 969         return ret;
 970 }
 971
 972 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 973 {
 974         int ret;
 975
 976         if (!capable(CAP_NET_ADMIN))
 977                 return -EPERM;
 978
 979         switch (cmd) {
 980         case ARPT_SO_SET_REPLACE:
 981                 ret = do_replace(user, len);
 982                 break;
 983
 984         case ARPT_SO_SET_ADD_COUNTERS:
 985                 ret = do_add_counters(user, len);
 986                 break;
 987
 988         default:
 989                 duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
 990                 ret = -EINVAL;
 991         }
 992
 993         return ret;
 994 }
 995
 996 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
 997 {
 998         int ret;
 999
1000         if (!capable(CAP_NET_ADMIN))
1001                 return -EPERM;
1002
1003         switch (cmd) {
1004         case ARPT_SO_GET_INFO: {
1005                 char name[ARPT_TABLE_MAXNAMELEN];
1006                 struct arpt_table *t;
1007
1008                 if (*len != sizeof(struct arpt_getinfo)) {
1009                         duprintf("length %u != %Zu\n", *len,
1010                                  sizeof(struct arpt_getinfo));
1011                         ret = -EINVAL;
1012                         break;
1013                 }
1014
1015                 if (copy_from_user(name, user, sizeof(name)) != 0) {
1016                         ret = -EFAULT;
1017                         break;
1018                 }
1019                 name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
1020
1021                 t = try_then_request_module(xt_find_table_lock(NF_ARP, name),
1022                                             "arptable_%s", name);
1023                 if (t && !IS_ERR(t)) {
1024                         struct arpt_getinfo info;
1025                         struct xt_table_info *private = t->private;
1026
1027                         info.valid_hooks = t->valid_hooks;
1028                         memcpy(info.hook_entry, private->hook_entry,
1029                                sizeof(info.hook_entry));
1030                         memcpy(info.underflow, private->underflow,
1031                                sizeof(info.underflow));
1032                         info.num_entries = private->number;
1033                         info.size = private->size;
1034                         strcpy(info.name, name);
1035
1036                         if (copy_to_user(user, &info, *len) != 0)
1037                                 ret = -EFAULT;
1038                         else
1039                                 ret = 0;
1040                         xt_table_unlock(t);
1041                         module_put(t->me);
1042                 } else
1043                         ret = t ? PTR_ERR(t) : -ENOENT;
1044         }
1045         break;
1046
1047         case ARPT_SO_GET_ENTRIES: {
1048                 struct arpt_get_entries get;
1049
1050                 if (*len < sizeof(get)) {
1051                         duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1052                         ret = -EINVAL;
1053                 } else if (copy_from_user(&get, user, sizeof(get)) != 0) {
1054                         ret = -EFAULT;
1055                 } else if (*len != sizeof(struct arpt_get_entries) + get.size) {
1056                         duprintf("get_entries: %u != %Zu\n", *len,
1057                                  sizeof(struct arpt_get_entries) + get.size);
1058                         ret = -EINVAL;
1059                 } else
1060                         ret = get_entries(&get, user);
1061                 break;
1062         }
1063
1064         case ARPT_SO_GET_REVISION_TARGET: {
1065                 struct xt_get_revision rev;
1066
1067                 if (*len != sizeof(rev)) {
1068                         ret = -EINVAL;
1069                         break;
1070                 }
1071                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1072                         ret = -EFAULT;
1073                         break;
1074                 }
1075
1076                 try_then_request_module(xt_find_revision(NF_ARP, rev.name,
1077                                                          rev.revision, 1, &ret),
1078                                         "arpt_%s", rev.name);
1079                 break;
1080         }
1081
1082         default:
1083                 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1084                 ret = -EINVAL;
1085         }
1086
1087         return ret;
1088 }
1089
1090 int arpt_register_table(struct arpt_table *table,
1091                         const struct arpt_replace *repl)
1092 {
1093         int ret;
1094         struct xt_table_info *newinfo;
1095         static struct xt_table_info bootstrap
1096                 = { 0, 0, 0, { 0 }, { 0 }, { } };
1097         void *loc_cpu_entry;
1098
1099         newinfo = xt_alloc_table_info(repl->size);
1100         if (!newinfo) {
1101                 ret = -ENOMEM;
1102                 return ret;
1103         }
1104
1105         /* choose the copy on our node/cpu */
1106         loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1107         memcpy(loc_cpu_entry, repl->entries, repl->size);
1108
1109         ret = translate_table(table->name, table->valid_hooks,
1110                               newinfo, loc_cpu_entry, repl->size,
1111                               repl->num_entries,
1112                               repl->hook_entry,
1113                               repl->underflow);
1114
1115         duprintf("arpt_register_table: translate table gives %d\n", ret);
1116         if (ret != 0) {
1117                 xt_free_table_info(newinfo);
1118                 return ret;
1119         }
1120
1121         if (xt_register_table(table, &bootstrap, newinfo) != 0) {
1122                 xt_free_table_info(newinfo);
1123                 return ret;
1124         }
1125
1126         return 0;
1127 }
1128
1129 void arpt_unregister_table(struct arpt_table *table)
1130 {
1131         struct xt_table_info *private;
1132         void *loc_cpu_entry;
1133
1134         private = xt_unregister_table(table);
1135
1136         /* Decrease module usage counts and free resources */
1137         loc_cpu_entry = private->entries[raw_smp_processor_id()];
1138         ARPT_ENTRY_ITERATE(loc_cpu_entry, private->size,
1139                            cleanup_entry, NULL);
1140         xt_free_table_info(private);
1141 }
1142
1143 /* The built-in targets: standard (NULL) and error. */
1144 static struct arpt_target arpt_standard_target = {
1145         .name           = ARPT_STANDARD_TARGET,
1146         .targetsize     = sizeof(int),
1147 };
1148
1149 static struct arpt_target arpt_error_target = {
1150         .name           = ARPT_ERROR_TARGET,
1151         .target         = arpt_error,
1152         .targetsize     = ARPT_FUNCTION_MAXNAMELEN,
1153 };
1154
1155 static struct nf_sockopt_ops arpt_sockopts = {
1156         .pf             = PF_INET,
1157         .set_optmin     = ARPT_BASE_CTL,
1158         .set_optmax     = ARPT_SO_SET_MAX+1,
1159         .set            = do_arpt_set_ctl,
1160         .get_optmin     = ARPT_BASE_CTL,
1161         .get_optmax     = ARPT_SO_GET_MAX+1,
1162         .get            = do_arpt_get_ctl,
1163 };
1164
1165 static int __init init(void)
1166 {
1167         int ret;
1168
1169         xt_proto_init(NF_ARP);
1170
1171         /* Noone else will be downing sem now, so we won't sleep */
1172         xt_register_target(NF_ARP, &arpt_standard_target);
1173         xt_register_target(NF_ARP, &arpt_error_target);
1174
1175         /* Register setsockopt */
1176         ret = nf_register_sockopt(&arpt_sockopts);
1177         if (ret < 0) {
1178                 duprintf("Unable to register sockopts.\n");
1179                 return ret;
1180         }
1181
1182         printk("arp_tables: (C) 2002 David S. Miller\n");
1183         return 0;
1184 }
1185
1186 static void __exit fini(void)
1187 {
1188         nf_unregister_sockopt(&arpt_sockopts);
1189         xt_proto_fini(NF_ARP);
1190 }
1191
1192 EXPORT_SYMBOL(arpt_register_table);
1193 EXPORT_SYMBOL(arpt_unregister_table);
1194 EXPORT_SYMBOL(arpt_do_table);
1195
1196 module_init(init);
1197 module_exit(fini);