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   1 /* iptables match extension to limit the number of packets per second
   2  * seperately for each hashbucket (sourceip/sourceport/dstip/dstport)
   3  *
   4  * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
   5  *
   6  * $Id: ipt_hashlimit.c 3244 2004-10-20 16:24:29Z laforge@netfilter.org $
   7  *
   8  * Development of this code was funded by Astaro AG, http://www.astaro.com/
   9  */
  10 #include <linux/module.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/random.h>
  13 #include <linux/jhash.h>
  14 #include <linux/slab.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/list.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/mm.h>
  21 #include <linux/in.h>
  22 #include <linux/ip.h>
  23 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  24 #include <linux/ipv6.h>
  25 #include <net/ipv6.h>
  26 #endif
  27
  28 #include <net/net_namespace.h>
  29
  30 #include <linux/netfilter/x_tables.h>
  31 #include <linux/netfilter_ipv4/ip_tables.h>
  32 #include <linux/netfilter_ipv6/ip6_tables.h>
  33 #include <linux/netfilter/xt_hashlimit.h>
  34 #include <linux/mutex.h>
  35
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  38 MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
  39 MODULE_ALIAS("ipt_hashlimit");
  40 MODULE_ALIAS("ip6t_hashlimit");
  41
  42 /* need to declare this at the top */
  43 static struct proc_dir_entry *hashlimit_procdir4;
  44 static struct proc_dir_entry *hashlimit_procdir6;
  45 static const struct file_operations dl_file_ops;
  46
  47 /* hash table crap */
  48 struct dsthash_dst {
  49         union {
  50                 struct {
  51                         __be32 src;
  52                         __be32 dst;
  53                 } ip;
  54 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  55                 struct {
  56                         __be32 src[4];
  57                         __be32 dst[4];
  58                 } ip6;
  59 #endif
  60         } addr;
  61         __be16 src_port;
  62         __be16 dst_port;
  63 };
  64
  65 struct dsthash_ent {
  66         /* static / read-only parts in the beginning */
  67         struct hlist_node node;
  68         struct dsthash_dst dst;
  69
  70         /* modified structure members in the end */
  71         unsigned long expires;          /* precalculated expiry time */
  72         struct {
  73                 unsigned long prev;     /* last modification */
  74                 u_int32_t credit;
  75                 u_int32_t credit_cap, cost;
  76         } rateinfo;
  77 };
  78
  79 struct xt_hashlimit_htable {
  80         struct hlist_node node;         /* global list of all htables */
  81         atomic_t use;
  82         int family;
  83
  84         struct hashlimit_cfg cfg;       /* config */
  85
  86         /* used internally */
  87         spinlock_t lock;                /* lock for list_head */
  88         u_int32_t rnd;                  /* random seed for hash */
  89         int rnd_initialized;
  90         unsigned int count;             /* number entries in table */
  91         struct timer_list timer;        /* timer for gc */
  92
  93         /* seq_file stuff */
  94         struct proc_dir_entry *pde;
  95
  96         struct hlist_head hash[0];      /* hashtable itself */
  97 };
  98
  99 static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
 100 static DEFINE_MUTEX(hlimit_mutex);      /* additional checkentry protection */
 101 static HLIST_HEAD(hashlimit_htables);
 102 static struct kmem_cache *hashlimit_cachep __read_mostly;
 103
 104 static inline bool dst_cmp(const struct dsthash_ent *ent,
 105                            const struct dsthash_dst *b)
 106 {
 107         return !memcmp(&ent->dst, b, sizeof(ent->dst));
 108 }
 109
 110 static u_int32_t
 111 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
 112 {
 113         u_int32_t hash = jhash2((const u32 *)dst,
 114                                 sizeof(*dst)/sizeof(u32),
 115                                 ht->rnd);
 116         /*
 117          * Instead of returning hash % ht->cfg.size (implying a divide)
 118          * we return the high 32 bits of the (hash * ht->cfg.size) that will
 119          * give results between [0 and cfg.size-1] and same hash distribution,
 120          * but using a multiply, less expensive than a divide
 121          */
 122         return ((u64)hash * ht->cfg.size) >> 32;
 123 }
 124
 125 static struct dsthash_ent *
 126 dsthash_find(const struct xt_hashlimit_htable *ht,
 127              const struct dsthash_dst *dst)
 128 {
 129         struct dsthash_ent *ent;
 130         struct hlist_node *pos;
 131         u_int32_t hash = hash_dst(ht, dst);
 132
 133         if (!hlist_empty(&ht->hash[hash])) {
 134                 hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
 135                         if (dst_cmp(ent, dst))
 136                                 return ent;
 137         }
 138         return NULL;
 139 }
 140
 141 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
 142 static struct dsthash_ent *
 143 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
 144                    const struct dsthash_dst *dst)
 145 {
 146         struct dsthash_ent *ent;
 147
 148         /* initialize hash with random val at the time we allocate
 149          * the first hashtable entry */
 150         if (!ht->rnd_initialized) {
 151                 get_random_bytes(&ht->rnd, 4);
 152                 ht->rnd_initialized = 1;
 153         }
 154
 155         if (ht->cfg.max && ht->count >= ht->cfg.max) {
 156                 /* FIXME: do something. question is what.. */
 157                 if (net_ratelimit())
 158                         printk(KERN_WARNING
 159                                 "xt_hashlimit: max count of %u reached\n",
 160                                 ht->cfg.max);
 161                 return NULL;
 162         }
 163
 164         ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
 165         if (!ent) {
 166                 if (net_ratelimit())
 167                         printk(KERN_ERR
 168                                 "xt_hashlimit: can't allocate dsthash_ent\n");
 169                 return NULL;
 170         }
 171         memcpy(&ent->dst, dst, sizeof(ent->dst));
 172
 173         hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
 174         ht->count++;
 175         return ent;
 176 }
 177
 178 static inline void
 179 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
 180 {
 181         hlist_del(&ent->node);
 182         kmem_cache_free(hashlimit_cachep, ent);
 183         ht->count--;
 184 }
 185 static void htable_gc(unsigned long htlong);
 186
 187 static int htable_create(struct xt_hashlimit_info *minfo, int family)
 188 {
 189         struct xt_hashlimit_htable *hinfo;
 190         unsigned int size;
 191         unsigned int i;
 192
 193         if (minfo->cfg.size)
 194                 size = minfo->cfg.size;
 195         else {
 196                 size = ((num_physpages << PAGE_SHIFT) / 16384) /
 197                        sizeof(struct list_head);
 198                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
 199                         size = 8192;
 200                 if (size < 16)
 201                         size = 16;
 202         }
 203         /* FIXME: don't use vmalloc() here or anywhere else -HW */
 204         hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
 205                         sizeof(struct list_head) * size);
 206         if (!hinfo) {
 207                 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
 208                 return -1;
 209         }
 210         minfo->hinfo = hinfo;
 211
 212         /* copy match config into hashtable config */
 213         memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
 214         hinfo->cfg.size = size;
 215         if (!hinfo->cfg.max)
 216                 hinfo->cfg.max = 8 * hinfo->cfg.size;
 217         else if (hinfo->cfg.max < hinfo->cfg.size)
 218                 hinfo->cfg.max = hinfo->cfg.size;
 219
 220         for (i = 0; i < hinfo->cfg.size; i++)
 221                 INIT_HLIST_HEAD(&hinfo->hash[i]);
 222
 223         atomic_set(&hinfo->use, 1);
 224         hinfo->count = 0;
 225         hinfo->family = family;
 226         hinfo->rnd_initialized = 0;
 227         spin_lock_init(&hinfo->lock);
 228         hinfo->pde = create_proc_entry(minfo->name, 0,
 229                                        family == AF_INET ? hashlimit_procdir4 :
 230                                                            hashlimit_procdir6);
 231         if (!hinfo->pde) {
 232                 vfree(hinfo);
 233                 return -1;
 234         }
 235         hinfo->pde->proc_fops = &dl_file_ops;
 236         hinfo->pde->data = hinfo;
 237
 238         setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo);
 239         hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
 240         add_timer(&hinfo->timer);
 241
 242         spin_lock_bh(&hashlimit_lock);
 243         hlist_add_head(&hinfo->node, &hashlimit_htables);
 244         spin_unlock_bh(&hashlimit_lock);
 245
 246         return 0;
 247 }
 248
 249 static bool select_all(const struct xt_hashlimit_htable *ht,
 250                        const struct dsthash_ent *he)
 251 {
 252         return 1;
 253 }
 254
 255 static bool select_gc(const struct xt_hashlimit_htable *ht,
 256                       const struct dsthash_ent *he)
 257 {
 258         return time_after_eq(jiffies, he->expires);
 259 }
 260
 261 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
 262                         bool (*select)(const struct xt_hashlimit_htable *ht,
 263                                       const struct dsthash_ent *he))
 264 {
 265         unsigned int i;
 266
 267         /* lock hash table and iterate over it */
 268         spin_lock_bh(&ht->lock);
 269         for (i = 0; i < ht->cfg.size; i++) {
 270                 struct dsthash_ent *dh;
 271                 struct hlist_node *pos, *n;
 272                 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
 273                         if ((*select)(ht, dh))
 274                                 dsthash_free(ht, dh);
 275                 }
 276         }
 277         spin_unlock_bh(&ht->lock);
 278 }
 279
 280 /* hash table garbage collector, run by timer */
 281 static void htable_gc(unsigned long htlong)
 282 {
 283         struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
 284
 285         htable_selective_cleanup(ht, select_gc);
 286
 287         /* re-add the timer accordingly */
 288         ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
 289         add_timer(&ht->timer);
 290 }
 291
 292 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
 293 {
 294         /* remove timer, if it is pending */
 295         if (timer_pending(&hinfo->timer))
 296                 del_timer(&hinfo->timer);
 297
 298         /* remove proc entry */
 299         remove_proc_entry(hinfo->pde->name,
 300                           hinfo->family == AF_INET ? hashlimit_procdir4 :
 301                                                      hashlimit_procdir6);
 302         htable_selective_cleanup(hinfo, select_all);
 303         vfree(hinfo);
 304 }
 305
 306 static struct xt_hashlimit_htable *htable_find_get(const char *name,
 307                                                    int family)
 308 {
 309         struct xt_hashlimit_htable *hinfo;
 310         struct hlist_node *pos;
 311
 312         spin_lock_bh(&hashlimit_lock);
 313         hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
 314                 if (!strcmp(name, hinfo->pde->name) &&
 315                     hinfo->family == family) {
 316                         atomic_inc(&hinfo->use);
 317                         spin_unlock_bh(&hashlimit_lock);
 318                         return hinfo;
 319                 }
 320         }
 321         spin_unlock_bh(&hashlimit_lock);
 322         return NULL;
 323 }
 324
 325 static void htable_put(struct xt_hashlimit_htable *hinfo)
 326 {
 327         if (atomic_dec_and_test(&hinfo->use)) {
 328                 spin_lock_bh(&hashlimit_lock);
 329                 hlist_del(&hinfo->node);
 330                 spin_unlock_bh(&hashlimit_lock);
 331                 htable_destroy(hinfo);
 332         }
 333 }
 334
 335 /* The algorithm used is the Simple Token Bucket Filter (TBF)
 336  * see net/sched/sch_tbf.c in the linux source tree
 337  */
 338
 339 /* Rusty: This is my (non-mathematically-inclined) understanding of
 340    this algorithm.  The `average rate' in jiffies becomes your initial
 341    amount of credit `credit' and the most credit you can ever have
 342    `credit_cap'.  The `peak rate' becomes the cost of passing the
 343    test, `cost'.
 344
 345    `prev' tracks the last packet hit: you gain one credit per jiffy.
 346    If you get credit balance more than this, the extra credit is
 347    discarded.  Every time the match passes, you lose `cost' credits;
 348    if you don't have that many, the test fails.
 349
 350    See Alexey's formal explanation in net/sched/sch_tbf.c.
 351
 352    To get the maximum range, we multiply by this factor (ie. you get N
 353    credits per jiffy).  We want to allow a rate as low as 1 per day
 354    (slowest userspace tool allows), which means
 355    CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
 356 */
 357 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
 358
 359 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
 360  * us the power of 2 below the theoretical max, so GCC simply does a
 361  * shift. */
 362 #define _POW2_BELOW2(x) ((x)|((x)>>1))
 363 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
 364 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
 365 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
 366 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
 367 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
 368
 369 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
 370
 371 /* Precision saver. */
 372 static inline u_int32_t
 373 user2credits(u_int32_t user)
 374 {
 375         /* If multiplying would overflow... */
 376         if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
 377                 /* Divide first. */
 378                 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
 379
 380         return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
 381 }
 382
 383 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
 384 {
 385         dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
 386         if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
 387                 dh->rateinfo.credit = dh->rateinfo.credit_cap;
 388         dh->rateinfo.prev = now;
 389 }
 390
 391 static int
 392 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
 393                    struct dsthash_dst *dst,
 394                    const struct sk_buff *skb, unsigned int protoff)
 395 {
 396         __be16 _ports[2], *ports;
 397         u8 nexthdr;
 398
 399         memset(dst, 0, sizeof(*dst));
 400
 401         switch (hinfo->family) {
 402         case AF_INET:
 403                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
 404                         dst->addr.ip.dst = ip_hdr(skb)->daddr;
 405                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
 406                         dst->addr.ip.src = ip_hdr(skb)->saddr;
 407
 408                 if (!(hinfo->cfg.mode &
 409                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
 410                         return 0;
 411                 nexthdr = ip_hdr(skb)->protocol;
 412                 break;
 413 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 414         case AF_INET6:
 415                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
 416                         memcpy(&dst->addr.ip6.dst, &ipv6_hdr(skb)->daddr,
 417                                sizeof(dst->addr.ip6.dst));
 418                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
 419                         memcpy(&dst->addr.ip6.src, &ipv6_hdr(skb)->saddr,
 420                                sizeof(dst->addr.ip6.src));
 421
 422                 if (!(hinfo->cfg.mode &
 423                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
 424                         return 0;
 425                 nexthdr = ipv6_hdr(skb)->nexthdr;
 426                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 427                 if ((int)protoff < 0)
 428                         return -1;
 429                 break;
 430 #endif
 431         default:
 432                 BUG();
 433                 return 0;
 434         }
 435
 436         switch (nexthdr) {
 437         case IPPROTO_TCP:
 438         case IPPROTO_UDP:
 439         case IPPROTO_UDPLITE:
 440         case IPPROTO_SCTP:
 441         case IPPROTO_DCCP:
 442                 ports = skb_header_pointer(skb, protoff, sizeof(_ports),
 443                                            &_ports);
 444                 break;
 445         default:
 446                 _ports[0] = _ports[1] = 0;
 447                 ports = _ports;
 448                 break;
 449         }
 450         if (!ports)
 451                 return -1;
 452         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
 453                 dst->src_port = ports[0];
 454         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
 455                 dst->dst_port = ports[1];
 456         return 0;
 457 }
 458
 459 static bool
 460 hashlimit_mt(const struct sk_buff *skb, const struct net_device *in,
 461              const struct net_device *out, const struct xt_match *match,
 462              const void *matchinfo, int offset, unsigned int protoff,
 463              bool *hotdrop)
 464 {
 465         const struct xt_hashlimit_info *r =
 466                 ((const struct xt_hashlimit_info *)matchinfo)->u.master;
 467         struct xt_hashlimit_htable *hinfo = r->hinfo;
 468         unsigned long now = jiffies;
 469         struct dsthash_ent *dh;
 470         struct dsthash_dst dst;
 471
 472         if (hashlimit_init_dst(hinfo, &dst, skb, protoff) < 0)
 473                 goto hotdrop;
 474
 475         spin_lock_bh(&hinfo->lock);
 476         dh = dsthash_find(hinfo, &dst);
 477         if (!dh) {
 478                 dh = dsthash_alloc_init(hinfo, &dst);
 479                 if (!dh) {
 480                         spin_unlock_bh(&hinfo->lock);
 481                         goto hotdrop;
 482                 }
 483
 484                 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
 485                 dh->rateinfo.prev = jiffies;
 486                 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
 487                                                    hinfo->cfg.burst);
 488                 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
 489                                                        hinfo->cfg.burst);
 490                 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
 491         } else {
 492                 /* update expiration timeout */
 493                 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
 494                 rateinfo_recalc(dh, now);
 495         }
 496
 497         if (dh->rateinfo.credit >= dh->rateinfo.cost) {
 498                 /* We're underlimit. */
 499                 dh->rateinfo.credit -= dh->rateinfo.cost;
 500                 spin_unlock_bh(&hinfo->lock);
 501                 return true;
 502         }
 503
 504         spin_unlock_bh(&hinfo->lock);
 505
 506         /* default case: we're overlimit, thus don't match */
 507         return false;
 508
 509 hotdrop:
 510         *hotdrop = true;
 511         return false;
 512 }
 513
 514 static bool
 515 hashlimit_mt_check(const char *tablename, const void *inf,
 516                    const struct xt_match *match, void *matchinfo,
 517                    unsigned int hook_mask)
 518 {
 519         struct xt_hashlimit_info *r = matchinfo;
 520
 521         /* Check for overflow. */
 522         if (r->cfg.burst == 0 ||
 523             user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
 524                 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
 525                        r->cfg.avg, r->cfg.burst);
 526                 return false;
 527         }
 528         if (r->cfg.mode == 0 ||
 529             r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
 530                            XT_HASHLIMIT_HASH_DIP |
 531                            XT_HASHLIMIT_HASH_SIP |
 532                            XT_HASHLIMIT_HASH_SPT))
 533                 return false;
 534         if (!r->cfg.gc_interval)
 535                 return false;
 536         if (!r->cfg.expire)
 537                 return false;
 538         if (r->name[sizeof(r->name) - 1] != '\0')
 539                 return false;
 540
 541         /* This is the best we've got: We cannot release and re-grab lock,
 542          * since checkentry() is called before x_tables.c grabs xt_mutex.
 543          * We also cannot grab the hashtable spinlock, since htable_create will
 544          * call vmalloc, and that can sleep.  And we cannot just re-search
 545          * the list of htable's in htable_create(), since then we would
 546          * create duplicate proc files. -HW */
 547         mutex_lock(&hlimit_mutex);
 548         r->hinfo = htable_find_get(r->name, match->family);
 549         if (!r->hinfo && htable_create(r, match->family) != 0) {
 550                 mutex_unlock(&hlimit_mutex);
 551                 return false;
 552         }
 553         mutex_unlock(&hlimit_mutex);
 554
 555         /* Ugly hack: For SMP, we only want to use one set */
 556         r->u.master = r;
 557         return true;
 558 }
 559
 560 static void
 561 hashlimit_mt_destroy(const struct xt_match *match, void *matchinfo)
 562 {
 563         const struct xt_hashlimit_info *r = matchinfo;
 564
 565         htable_put(r->hinfo);
 566 }
 567
 568 #ifdef CONFIG_COMPAT
 569 struct compat_xt_hashlimit_info {
 570         char name[IFNAMSIZ];
 571         struct hashlimit_cfg cfg;
 572         compat_uptr_t hinfo;
 573         compat_uptr_t master;
 574 };
 575
 576 static void hashlimit_mt_compat_from_user(void *dst, void *src)
 577 {
 578         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
 579
 580         memcpy(dst, src, off);
 581         memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
 582 }
 583
 584 static int hashlimit_mt_compat_to_user(void __user *dst, void *src)
 585 {
 586         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
 587
 588         return copy_to_user(dst, src, off) ? -EFAULT : 0;
 589 }
 590 #endif
 591
 592 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
 593         {
 594                 .name           = "hashlimit",
 595                 .family         = AF_INET,
 596                 .match          = hashlimit_mt,
 597                 .matchsize      = sizeof(struct xt_hashlimit_info),
 598 #ifdef CONFIG_COMPAT
 599                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
 600                 .compat_from_user = hashlimit_mt_compat_from_user,
 601                 .compat_to_user = hashlimit_mt_compat_to_user,
 602 #endif
 603                 .checkentry     = hashlimit_mt_check,
 604                 .destroy        = hashlimit_mt_destroy,
 605                 .me             = THIS_MODULE
 606         },
 607 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 608         {
 609                 .name           = "hashlimit",
 610                 .family         = AF_INET6,
 611                 .match          = hashlimit_mt,
 612                 .matchsize      = sizeof(struct xt_hashlimit_info),
 613 #ifdef CONFIG_COMPAT
 614                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
 615                 .compat_from_user = hashlimit_mt_compat_from_user,
 616                 .compat_to_user = hashlimit_mt_compat_to_user,
 617 #endif
 618                 .checkentry     = hashlimit_mt_check,
 619                 .destroy        = hashlimit_mt_destroy,
 620                 .me             = THIS_MODULE
 621         },
 622 #endif
 623 };
 624
 625 /* PROC stuff */
 626 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
 627         __acquires(htable->lock)
 628 {
 629         struct proc_dir_entry *pde = s->private;
 630         struct xt_hashlimit_htable *htable = pde->data;
 631         unsigned int *bucket;
 632
 633         spin_lock_bh(&htable->lock);
 634         if (*pos >= htable->cfg.size)
 635                 return NULL;
 636
 637         bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
 638         if (!bucket)
 639                 return ERR_PTR(-ENOMEM);
 640
 641         *bucket = *pos;
 642         return bucket;
 643 }
 644
 645 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
 646 {
 647         struct proc_dir_entry *pde = s->private;
 648         struct xt_hashlimit_htable *htable = pde->data;
 649         unsigned int *bucket = (unsigned int *)v;
 650
 651         *pos = ++(*bucket);
 652         if (*pos >= htable->cfg.size) {
 653                 kfree(v);
 654                 return NULL;
 655         }
 656         return bucket;
 657 }
 658
 659 static void dl_seq_stop(struct seq_file *s, void *v)
 660         __releases(htable->lock)
 661 {
 662         struct proc_dir_entry *pde = s->private;
 663         struct xt_hashlimit_htable *htable = pde->data;
 664         unsigned int *bucket = (unsigned int *)v;
 665
 666         kfree(bucket);
 667         spin_unlock_bh(&htable->lock);
 668 }
 669
 670 static int dl_seq_real_show(struct dsthash_ent *ent, int family,
 671                                    struct seq_file *s)
 672 {
 673         /* recalculate to show accurate numbers */
 674         rateinfo_recalc(ent, jiffies);
 675
 676         switch (family) {
 677         case AF_INET:
 678                 return seq_printf(s, "%ld %u.%u.%u.%u:%u->"
 679                                      "%u.%u.%u.%u:%u %u %u %u\n",
 680                                  (long)(ent->expires - jiffies)/HZ,
 681                                  NIPQUAD(ent->dst.addr.ip.src),
 682                                  ntohs(ent->dst.src_port),
 683                                  NIPQUAD(ent->dst.addr.ip.dst),
 684                                  ntohs(ent->dst.dst_port),
 685                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
 686                                  ent->rateinfo.cost);
 687 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 688         case AF_INET6:
 689                 return seq_printf(s, "%ld " NIP6_FMT ":%u->"
 690                                      NIP6_FMT ":%u %u %u %u\n",
 691                                  (long)(ent->expires - jiffies)/HZ,
 692                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.src),
 693                                  ntohs(ent->dst.src_port),
 694                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.dst),
 695                                  ntohs(ent->dst.dst_port),
 696                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
 697                                  ent->rateinfo.cost);
 698 #endif
 699         default:
 700                 BUG();
 701                 return 0;
 702         }
 703 }
 704
 705 static int dl_seq_show(struct seq_file *s, void *v)
 706 {
 707         struct proc_dir_entry *pde = s->private;
 708         struct xt_hashlimit_htable *htable = pde->data;
 709         unsigned int *bucket = (unsigned int *)v;
 710         struct dsthash_ent *ent;
 711         struct hlist_node *pos;
 712
 713         if (!hlist_empty(&htable->hash[*bucket])) {
 714                 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
 715                         if (dl_seq_real_show(ent, htable->family, s))
 716                                 return 1;
 717         }
 718         return 0;
 719 }
 720
 721 static const struct seq_operations dl_seq_ops = {
 722         .start = dl_seq_start,
 723         .next  = dl_seq_next,
 724         .stop  = dl_seq_stop,
 725         .show  = dl_seq_show
 726 };
 727
 728 static int dl_proc_open(struct inode *inode, struct file *file)
 729 {
 730         int ret = seq_open(file, &dl_seq_ops);
 731
 732         if (!ret) {
 733                 struct seq_file *sf = file->private_data;
 734                 sf->private = PDE(inode);
 735         }
 736         return ret;
 737 }
 738
 739 static const struct file_operations dl_file_ops = {
 740         .owner   = THIS_MODULE,
 741         .open    = dl_proc_open,
 742         .read    = seq_read,
 743         .llseek  = seq_lseek,
 744         .release = seq_release
 745 };
 746
 747 static int __init hashlimit_mt_init(void)
 748 {
 749         int err;
 750
 751         err = xt_register_matches(hashlimit_mt_reg,
 752               ARRAY_SIZE(hashlimit_mt_reg));
 753         if (err < 0)
 754                 goto err1;
 755
 756         err = -ENOMEM;
 757         hashlimit_cachep = kmem_cache_create("xt_hashlimit",
 758                                             sizeof(struct dsthash_ent), 0, 0,
 759                                             NULL);
 760         if (!hashlimit_cachep) {
 761                 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
 762                 goto err2;
 763         }
 764         hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", init_net.proc_net);
 765         if (!hashlimit_procdir4) {
 766                 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
 767                                 "entry\n");
 768                 goto err3;
 769         }
 770         err = 0;
 771 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 772         hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", init_net.proc_net);
 773         if (!hashlimit_procdir6) {
 774                 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
 775                                 "entry\n");
 776                 err = -ENOMEM;
 777         }
 778 #endif
 779         if (!err)
 780                 return 0;
 781         remove_proc_entry("ipt_hashlimit", init_net.proc_net);
 782 err3:
 783         kmem_cache_destroy(hashlimit_cachep);
 784 err2:
 785         xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
 786 err1:
 787         return err;
 788
 789 }
 790
 791 static void __exit hashlimit_mt_exit(void)
 792 {
 793         remove_proc_entry("ipt_hashlimit", init_net.proc_net);
 794 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 795         remove_proc_entry("ip6t_hashlimit", init_net.proc_net);
 796 #endif
 797         kmem_cache_destroy(hashlimit_cachep);
 798         xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
 799 }
 800
 801 module_init(hashlimit_mt_init);
 802 module_exit(hashlimit_mt_exit);