ClabureDB: Classified Bug-Reports Database

   /*
    * INET                An implementation of the TCP/IP protocol suite for the LINUX
    *                operating system.  INET is implemented using the  BSD Socket
    *                interface as the means of communication with the user level.
    *
    *                IPv4 FIB: lookup engine and maintenance routines.
    *
    * Authors:        Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
    *
   *                This program is free software; you can redistribute it and/or
   *                modify it under the terms of the GNU General Public License
   *                as published by the Free Software Foundation; either version
   *                2 of the License, or (at your option) any later version.
   */
  
  #include <asm/uaccess.h>
  #include <asm/system.h>
  #include <linux/bitops.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/string.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/errno.h>
  #include <linux/in.h>
  #include <linux/inet.h>
  #include <linux/inetdevice.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/proc_fs.h>
  #include <linux/skbuff.h>
  #include <linux/netlink.h>
  #include <linux/init.h>
  
  #include <net/net_namespace.h>
  #include <net/ip.h>
  #include <net/protocol.h>
  #include <net/route.h>
  #include <net/tcp.h>
  #include <net/sock.h>
  #include <net/ip_fib.h>
  
  #include "fib_lookup.h"
  
  static struct kmem_cache *fn_hash_kmem __read_mostly;
  static struct kmem_cache *fn_alias_kmem __read_mostly;
  
  struct fib_node {
          struct hlist_node        fn_hash;
          struct list_head        fn_alias;
          __be32                        fn_key;
          struct fib_alias        fn_embedded_alias;
  };
  
  struct fn_zone {
          struct fn_zone                *fz_next;        /* Next not empty zone        */
          struct hlist_head        *fz_hash;        /* Hash table pointer        */
          int                        fz_nent;        /* Number of entries        */
  
          int                        fz_divisor;        /* Hash divisor                */
          u32                        fz_hashmask;        /* (fz_divisor - 1)        */
  #define FZ_HASHMASK(fz)                ((fz)->fz_hashmask)
  
          int                        fz_order;        /* Zone order                */
          __be32                        fz_mask;
  #define FZ_MASK(fz)                ((fz)->fz_mask)
  };
  
  /* NOTE. On fast computers evaluation of fz_hashmask and fz_mask
   * can be cheaper than memory lookup, so that FZ_* macros are used.
   */
  
  struct fn_hash {
          struct fn_zone        *fn_zones[33];
          struct fn_zone        *fn_zone_list;
  };
  
  static inline u32 fn_hash(__be32 key, struct fn_zone *fz)
  {
          u32 h = ntohl(key)>>(32 - fz->fz_order);
          h ^= (h>>20);
          h ^= (h>>10);
          h ^= (h>>5);
          h &= FZ_HASHMASK(fz);
          return h;
  }
  
  static inline __be32 fz_key(__be32 dst, struct fn_zone *fz)
  {
          return dst & FZ_MASK(fz);
  }
  
  static DEFINE_RWLOCK(fib_hash_lock);
  static unsigned int fib_hash_genid;
  
  #define FZ_MAX_DIVISOR ((PAGE_SIZE<<MAX_ORDER) / sizeof(struct hlist_head))
  
  static struct hlist_head *fz_hash_alloc(int divisor)
 {
         unsigned long size = divisor * sizeof(struct hlist_head);
 
         if (size <= PAGE_SIZE) {
                 return kzalloc(size, GFP_KERNEL);
         } else {
                 return (struct hlist_head *)
                         __get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(size));
         }
 }
 
 /* The fib hash lock must be held when this is called. */
 static inline void fn_rebuild_zone(struct fn_zone *fz,
                                    struct hlist_head *old_ht,
                                    int old_divisor)
 {
         int i;
 
         for (i = 0; i < old_divisor; i++) {
                 struct hlist_node *node, *n;
                 struct fib_node *f;
 
                 hlist_for_each_entry_safe(f, node, n, &old_ht[i], fn_hash) {
                         struct hlist_head *new_head;
 
                         hlist_del(&f->fn_hash);
 
                         new_head = &fz->fz_hash[fn_hash(f->fn_key, fz)];
                         hlist_add_head(&f->fn_hash, new_head);
                 }
         }
 }
 
 static void fz_hash_free(struct hlist_head *hash, int divisor)
 {
         unsigned long size = divisor * sizeof(struct hlist_head);
 
         if (size <= PAGE_SIZE)
                 kfree(hash);
         else
                 free_pages((unsigned long)hash, get_order(size));
 }
 
 static void fn_rehash_zone(struct fn_zone *fz)
 {
         struct hlist_head *ht, *old_ht;
         int old_divisor, new_divisor;
         u32 new_hashmask;
 
         old_divisor = fz->fz_divisor;
 
         switch (old_divisor) {
         case 16:
                 new_divisor = 256;
                 break;
         case 256:
                 new_divisor = 1024;
                 break;
         default:
                 if ((old_divisor << 1) > FZ_MAX_DIVISOR) {
                         printk(KERN_CRIT "route.c: bad divisor %d!\n", old_divisor);
                         return;
                 }
                 new_divisor = (old_divisor << 1);
                 break;
         }
 
         new_hashmask = (new_divisor - 1);
 
 #if RT_CACHE_DEBUG >= 2
         printk(KERN_DEBUG "fn_rehash_zone: hash for zone %d grows from %d\n",
                fz->fz_order, old_divisor);
 #endif
 
         ht = fz_hash_alloc(new_divisor);
 
         if (ht)        {
                 write_lock_bh(&fib_hash_lock);
                 old_ht = fz->fz_hash;
                 fz->fz_hash = ht;
                 fz->fz_hashmask = new_hashmask;
                 fz->fz_divisor = new_divisor;
                 fn_rebuild_zone(fz, old_ht, old_divisor);
                 fib_hash_genid++;
                 write_unlock_bh(&fib_hash_lock);
 
                 fz_hash_free(old_ht, old_divisor);
         }
 }
 
 static inline void fn_free_node(struct fib_node * f)
 {
         kmem_cache_free(fn_hash_kmem, f);
 }
 
 static inline void fn_free_alias(struct fib_alias *fa, struct fib_node *f)
 {
         fib_release_info(fa->fa_info);
         if (fa == &f->fn_embedded_alias)
                 fa->fa_info = NULL;
         else
                 kmem_cache_free(fn_alias_kmem, fa);
 }
 
 static struct fn_zone *
 fn_new_zone(struct fn_hash *table, int z)
 {
         int i;
         struct fn_zone *fz = kzalloc(sizeof(struct fn_zone), GFP_KERNEL);
         if (!fz)
                 return NULL;
 
         if (z) {
                 fz->fz_divisor = 16;
         } else {
                 fz->fz_divisor = 1;
         }
         fz->fz_hashmask = (fz->fz_divisor - 1);
         fz->fz_hash = fz_hash_alloc(fz->fz_divisor);
         if (!fz->fz_hash) {
                 kfree(fz);
                 return NULL;
         }
         fz->fz_order = z;
         fz->fz_mask = inet_make_mask(z);
 
         /* Find the first not empty zone with more specific mask */
         for (i=z+1; i<=32; i++)
                 if (table->fn_zones[i])
                         break;
         write_lock_bh(&fib_hash_lock);
         if (i>32) {
                 /* No more specific masks, we are the first. */
                 fz->fz_next = table->fn_zone_list;
                 table->fn_zone_list = fz;
         } else {
                 fz->fz_next = table->fn_zones[i]->fz_next;
                 table->fn_zones[i]->fz_next = fz;
         }
         table->fn_zones[z] = fz;
         fib_hash_genid++;
         write_unlock_bh(&fib_hash_lock);
         return fz;
 }
 
 static int
 fn_hash_lookup(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
 {
         int err;
         struct fn_zone *fz;
         struct fn_hash *t = (struct fn_hash*)tb->tb_data;
 
         read_lock(&fib_hash_lock);
         for (fz = t->fn_zone_list; fz; fz = fz->fz_next) {
                 struct hlist_head *head;
                 struct hlist_node *node;
                 struct fib_node *f;
                 __be32 k = fz_key(flp->fl4_dst, fz);
 
                 head = &fz->fz_hash[fn_hash(k, fz)];
                 hlist_for_each_entry(f, node, head, fn_hash) {
                         if (f->fn_key != k)
                                 continue;
 
                         err = fib_semantic_match(&f->fn_alias,
                                                  flp, res,
                                                  f->fn_key, fz->fz_mask,
                                                  fz->fz_order);
                         if (err <= 0)
                                 goto out;
                 }
         }
         err = 1;
 out:
         read_unlock(&fib_hash_lock);
         return err;
 }
 
 static void
 fn_hash_select_default(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
 {
         int order, last_idx;
         struct hlist_node *node;
         struct fib_node *f;
         struct fib_info *fi = NULL;
         struct fib_info *last_resort;
         struct fn_hash *t = (struct fn_hash*)tb->tb_data;
         struct fn_zone *fz = t->fn_zones[0];
 
         if (fz == NULL)
                 return;
 
         last_idx = -1;
         last_resort = NULL;
         order = -1;
 
         read_lock(&fib_hash_lock);
         hlist_for_each_entry(f, node, &fz->fz_hash[0], fn_hash) {
                 struct fib_alias *fa;
 
                 list_for_each_entry(fa, &f->fn_alias, fa_list) {
                         struct fib_info *next_fi = fa->fa_info;
 
                         if (fa->fa_scope != res->scope ||
                             fa->fa_type != RTN_UNICAST)
                                 continue;
 
                         if (next_fi->fib_priority > res->fi->fib_priority)
                                 break;
                         if (!next_fi->fib_nh[0].nh_gw ||
                             next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
                                 continue;
                         fa->fa_state |= FA_S_ACCESSED;
 
                         if (fi == NULL) {
                                 if (next_fi != res->fi)
                                         break;
                         } else if (!fib_detect_death(fi, order, &last_resort,
                                                 &last_idx, tb->tb_default)) {
                                 fib_result_assign(res, fi);
                                 tb->tb_default = order;
                                 goto out;
                         }
                         fi = next_fi;
                         order++;
                 }
         }
 
         if (order <= 0 || fi == NULL) {
                 tb->tb_default = -1;
                 goto out;
         }
 
         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
                                 tb->tb_default)) {
                 fib_result_assign(res, fi);
                 tb->tb_default = order;
                 goto out;
         }
 
         if (last_idx >= 0)
                 fib_result_assign(res, last_resort);
         tb->tb_default = last_idx;
 out:
         read_unlock(&fib_hash_lock);
 }
 
 /* Insert node F to FZ. */
 static inline void fib_insert_node(struct fn_zone *fz, struct fib_node *f)
 {
         struct hlist_head *head = &fz->fz_hash[fn_hash(f->fn_key, fz)];
 
         hlist_add_head(&f->fn_hash, head);
 }
 
 /* Return the node in FZ matching KEY. */
 static struct fib_node *fib_find_node(struct fn_zone *fz, __be32 key)
 {
         struct hlist_head *head = &fz->fz_hash[fn_hash(key, fz)];
         struct hlist_node *node;
         struct fib_node *f;
 
         hlist_for_each_entry(f, node, head, fn_hash) {
                 if (f->fn_key == key)
                         return f;
         }
 
         return NULL;
 }
 
 static int fn_hash_insert(struct fib_table *tb, struct fib_config *cfg)
 {
         struct fn_hash *table = (struct fn_hash *) tb->tb_data;
         struct fib_node *new_f = NULL;
         struct fib_node *f;
         struct fib_alias *fa, *new_fa;
         struct fn_zone *fz;
         struct fib_info *fi;
         u8 tos = cfg->fc_tos;
         __be32 key;
         int err;
 
         if (cfg->fc_dst_len > 32)
                 return -EINVAL;
 
         fz = table->fn_zones[cfg->fc_dst_len];
         if (!fz && !(fz = fn_new_zone(table, cfg->fc_dst_len)))
                 return -ENOBUFS;
 
         key = 0;
         if (cfg->fc_dst) {
                 if (cfg->fc_dst & ~FZ_MASK(fz))
                         return -EINVAL;
                 key = fz_key(cfg->fc_dst, fz);
         }
 
         fi = fib_create_info(cfg);
         if (IS_ERR(fi))
                 return PTR_ERR(fi);
 
         if (fz->fz_nent > (fz->fz_divisor<<1) &&
             fz->fz_divisor < FZ_MAX_DIVISOR &&
             (cfg->fc_dst_len == 32 ||
              (1 << cfg->fc_dst_len) > fz->fz_divisor))
                 fn_rehash_zone(fz);
 
         f = fib_find_node(fz, key);
 
         if (!f)
                 fa = NULL;
         else
                 fa = fib_find_alias(&f->fn_alias, tos, fi->fib_priority);
 
         /* Now fa, if non-NULL, points to the first fib alias
          * with the same keys [prefix,tos,priority], if such key already
          * exists or to the node before which we will insert new one.
          *
          * If fa is NULL, we will need to allocate a new one and
          * insert to the head of f.
          *
          * If f is NULL, no fib node matched the destination key
          * and we need to allocate a new one of those as well.
          */
 
         if (fa && fa->fa_tos == tos &&
             fa->fa_info->fib_priority == fi->fib_priority) {
                 struct fib_alias *fa_first, *fa_match;
 
                 err = -EEXIST;
                 if (cfg->fc_nlflags & NLM_F_EXCL)
                         goto out;
 
                 /* We have 2 goals:
                  * 1. Find exact match for type, scope, fib_info to avoid
                  * duplicate routes
                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
                  */
                 fa_match = NULL;
                 fa_first = fa;
                 fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
                 list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
                         if (fa->fa_tos != tos)
                                 break;
                         if (fa->fa_info->fib_priority != fi->fib_priority)
                                 break;
                         if (fa->fa_type == cfg->fc_type &&
                             fa->fa_scope == cfg->fc_scope &&
                             fa->fa_info == fi) {
                                 fa_match = fa;
                                 break;
                         }
                 }
 
                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
                         struct fib_info *fi_drop;
                         u8 state;
 
                         fa = fa_first;
                         if (fa_match) {
                                 if (fa == fa_match)
                                         err = 0;
                                 goto out;
                         }
                         write_lock_bh(&fib_hash_lock);
                         fi_drop = fa->fa_info;
                         fa->fa_info = fi;
                         fa->fa_type = cfg->fc_type;
                         fa->fa_scope = cfg->fc_scope;
                         state = fa->fa_state;
                         fa->fa_state &= ~FA_S_ACCESSED;
                         fib_hash_genid++;
                         write_unlock_bh(&fib_hash_lock);
 
                         fib_release_info(fi_drop);
                         if (state & FA_S_ACCESSED)
                                 rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
                         rtmsg_fib(RTM_NEWROUTE, key, fa, cfg->fc_dst_len, tb->tb_id,
                                   &cfg->fc_nlinfo, NLM_F_REPLACE);
                         return 0;
                 }
 
                 /* Error if we find a perfect match which
                  * uses the same scope, type, and nexthop
                  * information.
                  */
                 if (fa_match)
                         goto out;
 
                 if (!(cfg->fc_nlflags & NLM_F_APPEND))
                         fa = fa_first;
         }
 
         err = -ENOENT;
         if (!(cfg->fc_nlflags & NLM_F_CREATE))
                 goto out;
 
         err = -ENOBUFS;
 
         if (!f) {
                 new_f = kmem_cache_zalloc(fn_hash_kmem, GFP_KERNEL);
                 if (new_f == NULL)
                         goto out;
 
                 INIT_HLIST_NODE(&new_f->fn_hash);
                 INIT_LIST_HEAD(&new_f->fn_alias);
                 new_f->fn_key = key;
                 f = new_f;
         }
 
         new_fa = &f->fn_embedded_alias;
         if (new_fa->fa_info != NULL) {
                 new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
                 if (new_fa == NULL)
                         goto out;
         }
         new_fa->fa_info = fi;
         new_fa->fa_tos = tos;
         new_fa->fa_type = cfg->fc_type;
         new_fa->fa_scope = cfg->fc_scope;
         new_fa->fa_state = 0;
 
         /*
          * Insert new entry to the list.
          */
 
         write_lock_bh(&fib_hash_lock);
         if (new_f)
                 fib_insert_node(fz, new_f);
         list_add_tail(&new_fa->fa_list,
                  (fa ? &fa->fa_list : &f->fn_alias));
         fib_hash_genid++;
         write_unlock_bh(&fib_hash_lock);
 
         if (new_f)
                 fz->fz_nent++;
         rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
 
         rtmsg_fib(RTM_NEWROUTE, key, new_fa, cfg->fc_dst_len, tb->tb_id,
                   &cfg->fc_nlinfo, 0);
         return 0;
 
 out:
         if (new_f)
                 kmem_cache_free(fn_hash_kmem, new_f);
         fib_release_info(fi);
         return err;
 }
 
 
 static int fn_hash_delete(struct fib_table *tb, struct fib_config *cfg)
 {
         struct fn_hash *table = (struct fn_hash*)tb->tb_data;
         struct fib_node *f;
         struct fib_alias *fa, *fa_to_delete;
         struct fn_zone *fz;
         __be32 key;
 
         if (cfg->fc_dst_len > 32)
                 return -EINVAL;
 
         if ((fz  = table->fn_zones[cfg->fc_dst_len]) == NULL)
                 return -ESRCH;
 
         key = 0;
         if (cfg->fc_dst) {
                 if (cfg->fc_dst & ~FZ_MASK(fz))
                         return -EINVAL;
                 key = fz_key(cfg->fc_dst, fz);
         }
 
         f = fib_find_node(fz, key);
 
         if (!f)
                 fa = NULL;
         else
                 fa = fib_find_alias(&f->fn_alias, cfg->fc_tos, 0);
         if (!fa)
                 return -ESRCH;
 
         fa_to_delete = NULL;
         fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
         list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
                 struct fib_info *fi = fa->fa_info;
 
                 if (fa->fa_tos != cfg->fc_tos)
                         break;
 
                 if ((!cfg->fc_type ||
                      fa->fa_type == cfg->fc_type) &&
                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
                      fa->fa_scope == cfg->fc_scope) &&
                     (!cfg->fc_protocol ||
                      fi->fib_protocol == cfg->fc_protocol) &&
                     fib_nh_match(cfg, fi) == 0) {
                         fa_to_delete = fa;
                         break;
                 }
         }
 
         if (fa_to_delete) {
                 int kill_fn;
 
                 fa = fa_to_delete;
                 rtmsg_fib(RTM_DELROUTE, key, fa, cfg->fc_dst_len,
                           tb->tb_id, &cfg->fc_nlinfo, 0);
 
                 kill_fn = 0;
                 write_lock_bh(&fib_hash_lock);
                 list_del(&fa->fa_list);
                 if (list_empty(&f->fn_alias)) {
                         hlist_del(&f->fn_hash);
                         kill_fn = 1;
                 }
                 fib_hash_genid++;
                 write_unlock_bh(&fib_hash_lock);
 
                 if (fa->fa_state & FA_S_ACCESSED)
                         rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
                 fn_free_alias(fa, f);
                 if (kill_fn) {
                         fn_free_node(f);
                         fz->fz_nent--;
                 }
 
                 return 0;
         }
         return -ESRCH;
 }
 
 static int fn_flush_list(struct fn_zone *fz, int idx)
 {
         struct hlist_head *head = &fz->fz_hash[idx];
         struct hlist_node *node, *n;
         struct fib_node *f;
         int found = 0;
 
         hlist_for_each_entry_safe(f, node, n, head, fn_hash) {
                 struct fib_alias *fa, *fa_node;
                 int kill_f;
 
                 kill_f = 0;
                 list_for_each_entry_safe(fa, fa_node, &f->fn_alias, fa_list) {
                         struct fib_info *fi = fa->fa_info;
 
                         if (fi && (fi->fib_flags&RTNH_F_DEAD)) {
                                 write_lock_bh(&fib_hash_lock);
                                 list_del(&fa->fa_list);
                                 if (list_empty(&f->fn_alias)) {
                                         hlist_del(&f->fn_hash);
                                         kill_f = 1;
                                 }
                                 fib_hash_genid++;
                                 write_unlock_bh(&fib_hash_lock);
 
                                 fn_free_alias(fa, f);
                                 found++;
                         }
                 }
                 if (kill_f) {
                         fn_free_node(f);
                         fz->fz_nent--;
                 }
         }
         return found;
 }
 
 static int fn_hash_flush(struct fib_table *tb)
 {
         struct fn_hash *table = (struct fn_hash *) tb->tb_data;
         struct fn_zone *fz;
         int found = 0;
 
         for (fz = table->fn_zone_list; fz; fz = fz->fz_next) {
                 int i;
 
                 for (i = fz->fz_divisor - 1; i >= 0; i--)
                         found += fn_flush_list(fz, i);
         }
         return found;
 }
 
 
 static inline int
 fn_hash_dump_bucket(struct sk_buff *skb, struct netlink_callback *cb,
                      struct fib_table *tb,
                      struct fn_zone *fz,
                      struct hlist_head *head)
 {
         struct hlist_node *node;
         struct fib_node *f;
         int i, s_i;
 
         s_i = cb->args[4];
         i = 0;
         hlist_for_each_entry(f, node, head, fn_hash) {
                 struct fib_alias *fa;
 
                 list_for_each_entry(fa, &f->fn_alias, fa_list) {
                         if (i < s_i)
                                 goto next;
 
                         if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
                                           cb->nlh->nlmsg_seq,
                                           RTM_NEWROUTE,
                                           tb->tb_id,
                                           fa->fa_type,
                                           fa->fa_scope,
                                           f->fn_key,
                                           fz->fz_order,
                                           fa->fa_tos,
                                           fa->fa_info,
                                           NLM_F_MULTI) < 0) {
                                 cb->args[4] = i;
                                 return -1;
                         }
                 next:
                         i++;
                 }
         }
         cb->args[4] = i;
         return skb->len;
 }
 
 static inline int
 fn_hash_dump_zone(struct sk_buff *skb, struct netlink_callback *cb,
                    struct fib_table *tb,
                    struct fn_zone *fz)
 {
         int h, s_h;
 
         if (fz->fz_hash == NULL)
                 return skb->len;
         s_h = cb->args[3];
         for (h = s_h; h < fz->fz_divisor; h++) {
                 if (hlist_empty(&fz->fz_hash[h]))
                         continue;
                 if (fn_hash_dump_bucket(skb, cb, tb, fz, &fz->fz_hash[h]) < 0) {
                         cb->args[3] = h;
                         return -1;
                 }
                 memset(&cb->args[4], 0,
                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
         }
         cb->args[3] = h;
         return skb->len;
 }
 
 static int fn_hash_dump(struct fib_table *tb, struct sk_buff *skb, struct netlink_callback *cb)
 {
         int m, s_m;
         struct fn_zone *fz;
         struct fn_hash *table = (struct fn_hash*)tb->tb_data;
 
         s_m = cb->args[2];
         read_lock(&fib_hash_lock);
         for (fz = table->fn_zone_list, m=0; fz; fz = fz->fz_next, m++) {
                 if (m < s_m) continue;
                 if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
                         cb->args[2] = m;
                         read_unlock(&fib_hash_lock);
                         return -1;
                 }
                 memset(&cb->args[3], 0,
                        sizeof(cb->args) - 3*sizeof(cb->args[0]));
         }
         read_unlock(&fib_hash_lock);
         cb->args[2] = m;
         return skb->len;
 }
 
 void __init fib_hash_init(void)
 {
         fn_hash_kmem = kmem_cache_create("ip_fib_hash", sizeof(struct fib_node),
                                          0, SLAB_PANIC, NULL);
 
         fn_alias_kmem = kmem_cache_create("ip_fib_alias", sizeof(struct fib_alias),
                                           0, SLAB_PANIC, NULL);
 
 }
 
 struct fib_table *fib_hash_table(u32 id)
 {
         struct fib_table *tb;
 
         tb = kmalloc(sizeof(struct fib_table) + sizeof(struct fn_hash),
                      GFP_KERNEL);
         if (tb == NULL)
                 return NULL;
 
         tb->tb_id = id;
         tb->tb_default = -1;
         tb->tb_lookup = fn_hash_lookup;
         tb->tb_insert = fn_hash_insert;
         tb->tb_delete = fn_hash_delete;
         tb->tb_flush = fn_hash_flush;
         tb->tb_select_default = fn_hash_select_default;
         tb->tb_dump = fn_hash_dump;
         memset(tb->tb_data, 0, sizeof(struct fn_hash));
         return tb;
 }
 
 /* ------------------------------------------------------------------------ */
 #ifdef CONFIG_PROC_FS
 
 struct fib_iter_state {
         struct seq_net_private p;
         struct fn_zone        *zone;
         int                bucket;
         struct hlist_head *hash_head;
         struct fib_node *fn;
         struct fib_alias *fa;
         loff_t pos;
         unsigned int genid;
         int valid;
 };
 
 static struct fib_alias *fib_get_first(struct seq_file *seq)
 {
         struct fib_iter_state *iter = seq->private;
         struct fib_table *main_table;
         struct fn_hash *table;
 
         main_table = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
         table = (struct fn_hash *)main_table->tb_data;
 
         iter->bucket    = 0;
         iter->hash_head = NULL;
         iter->fn        = NULL;
         iter->fa        = NULL;
         iter->pos        = 0;
         iter->genid        = fib_hash_genid;
         iter->valid        = 1;
 
         for (iter->zone = table->fn_zone_list; iter->zone;
              iter->zone = iter->zone->fz_next) {
                 int maxslot;
 
                 if (!iter->zone->fz_nent)
                         continue;
 
                 iter->hash_head = iter->zone->fz_hash;
                 maxslot = iter->zone->fz_divisor;
 
                 for (iter->bucket = 0; iter->bucket < maxslot;
                      ++iter->bucket, ++iter->hash_head) {
                         struct hlist_node *node;
                         struct fib_node *fn;
 
                         hlist_for_each_entry(fn,node,iter->hash_head,fn_hash) {
                                 struct fib_alias *fa;
 
                                 list_for_each_entry(fa,&fn->fn_alias,fa_list) {
                                         iter->fn = fn;
                                         iter->fa = fa;
                                         goto out;
                                 }
                         }
                 }
         }
 out:
         return iter->fa;
 }
 
 static struct fib_alias *fib_get_next(struct seq_file *seq)
 {
         struct fib_iter_state *iter = seq->private;
         struct fib_node *fn;
         struct fib_alias *fa;
 
         /* Advance FA, if any. */
         fn = iter->fn;
         fa = iter->fa;
         if (fa) {
                 BUG_ON(!fn);
                 list_for_each_entry_continue(fa, &fn->fn_alias, fa_list) {
                         iter->fa = fa;
                         goto out;
                 }
         }
 
         fa = iter->fa = NULL;
 
         /* Advance FN. */
         if (fn) {
                 struct hlist_node *node = &fn->fn_hash;
                 hlist_for_each_entry_continue(fn, node, fn_hash) {
                         iter->fn = fn;
 
                         list_for_each_entry(fa, &fn->fn_alias, fa_list) {
                                 iter->fa = fa;
                                 goto out;
                         }
                 }
         }
 
         fn = iter->fn = NULL;
 
         /* Advance hash chain. */
         if (!iter->zone)
                 goto out;
 
         for (;;) {
                 struct hlist_node *node;
                 int maxslot;
 
                 maxslot = iter->zone->fz_divisor;
 
                 while (++iter->bucket < maxslot) {
                         iter->hash_head++;
 
                         hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
                                 list_for_each_entry(fa, &fn->fn_alias, fa_list) {
                                         iter->fn = fn;
                                         iter->fa = fa;
                                         goto out;
                                 }
                         }
                 }
 
                 iter->zone = iter->zone->fz_next;
 
                 if (!iter->zone)
                         goto out;
 
                 iter->bucket = 0;
                 iter->hash_head = iter->zone->fz_hash;
 
                 hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
                         list_for_each_entry(fa, &fn->fn_alias, fa_list) {
                                 iter->fn = fn;
                                 iter->fa = fa;
                                 goto out;
                         }
                 }
         }
 out:
         iter->pos++;
         return fa;
 }
 
 static struct fib_alias *fib_get_idx(struct seq_file *seq, loff_t pos)
 {
         struct fib_iter_state *iter = seq->private;
         struct fib_alias *fa;
 
         if (iter->valid && pos >= iter->pos && iter->genid == fib_hash_genid) {
                 fa   = iter->fa;
                 pos -= iter->pos;
         } else
                 fa = fib_get_first(seq);
 
         if (fa)
                 while (pos && (fa = fib_get_next(seq)))
                         --pos;
         return pos ? NULL : fa;
 }
 
 static void *fib_seq_start(struct seq_file *seq, loff_t *pos)
         __acquires(fib_hash_lock)
 {
         void *v = NULL;
 
         read_lock(&fib_hash_lock);
         if (fib_get_table(seq_file_net(seq), RT_TABLE_MAIN))
                 v = *pos ? fib_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
         return v;
 }
 
 static void *fib_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
         ++*pos;
         return v == SEQ_START_TOKEN ? fib_get_first(seq) : fib_get_next(seq);
 }
 
 static void fib_seq_stop(struct seq_file *seq, void *v)
         __releases(fib_hash_lock)
 {
         read_unlock(&fib_hash_lock);
 }
 
 static unsigned fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
 {
         static const unsigned type2flags[RTN_MAX + 1] = {
                 [7] = RTF_REJECT, [8] = RTF_REJECT,
         };
         unsigned flags = type2flags[type];
 
         if (fi && fi->fib_nh->nh_gw)
                 flags |= RTF_GATEWAY;
         if (mask == htonl(0xFFFFFFFF))
                 flags |= RTF_HOST;
         flags |= RTF_UP;
         return flags;
 }
 
 /*
  *        This outputs /proc/net/route.
  *
  *        It always works in backward compatibility mode.
  *        The format of the file is not supposed to be changed.
 */
static int fib_seq_show(struct seq_file *seq, void *v)
{
        struct fib_iter_state *iter;
        int len;
        __be32 prefix, mask;
        unsigned flags;
        struct fib_node *f;
        struct fib_alias *fa;
        struct fib_info *fi;

        if (v == SEQ_START_TOKEN) {
                seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
                           "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
                           "\tWindow\tIRTT");
                goto out;
        }

        iter        = seq->private;
        f        = iter->fn;
        fa        = iter->fa;
        fi        = fa->fa_info;
        prefix        = f->fn_key;
        mask        = FZ_MASK(iter->zone);
        flags        = fib_flag_trans(fa->fa_type, mask, fi);
        if (fi)
                seq_printf(seq,
                         "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u%n",
                         fi->fib_dev ? fi->fib_dev->name : "*", prefix,
                         fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
                         mask, (fi->fib_advmss ? fi->fib_advmss + 40 : 0),
                         fi->fib_window,
                         fi->fib_rtt >> 3, &len);
        else
                seq_printf(seq,
                         "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u%n",
                         prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0, &len);

        seq_printf(seq, "%*s\n", 127 - len, "");
out:
        return 0;
}

static const struct seq_operations fib_seq_ops = {
        .start  = fib_seq_start,
        .next   = fib_seq_next,
        .stop   = fib_seq_stop,
        .show   = fib_seq_show,
};

static int fib_seq_open(struct inode *inode, struct file *file)
{
        return seq_open_net(inode, file, &fib_seq_ops,
                            sizeof(struct fib_iter_state));
}

static const struct file_operations fib_seq_fops = {
        .owner                = THIS_MODULE,
        .open           = fib_seq_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release_net,
};

int __net_init fib_proc_init(struct net *net)
{
        if (!proc_net_fops_create(net, "route", S_IRUGO, &fib_seq_fops))
                return -ENOMEM;
        return 0;
}

void __net_exit fib_proc_exit(struct net *net)
{
        proc_net_remove(net, "route");
}
#endif /* CONFIG_PROC_FS */