pch_gbe dreiver: chang author

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv4 / fib_hash.c

/*
 * 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 <linux/slab.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;
};

#define EMBEDDED_HASH_SIZE (L1_CACHE_BYTES / sizeof(struct hlist_head))

struct fn_zone {
        struct fn_zone __rcu    *fz_next;       /* Next not empty zone  */
        struct hlist_head __rcu *fz_hash;       /* Hash table pointer   */
        seqlock_t               fz_lock;
        u32                     fz_hashmask;    /* (fz_divisor - 1)     */

        u8                      fz_order;       /* Zone order (0..32)   */
        u8                      fz_revorder;    /* 32 - fz_order        */
        __be32                  fz_mask;        /* inet_make_mask(order) */
#define FZ_MASK(fz)             ((fz)->fz_mask)

        struct hlist_head       fz_embedded_hash[EMBEDDED_HASH_SIZE];

        int                     fz_nent;        /* Number of entries    */
        int                     fz_divisor;     /* Hash size (mask+1)   */
};

struct fn_hash {
        struct fn_zone          *fn_zones[33];
        struct fn_zone __rcu    *fn_zone_list;
};

static inline u32 fn_hash(__be32 key, struct fn_zone *fz)
{
        u32 h = ntohl(key) >> fz->fz_revorder;
        h ^= (h>>20);
        h ^= (h>>10);
        h ^= (h>>5);
        h &= fz->fz_hashmask;
        return h;
}

static inline __be32 fz_key(__be32 dst, struct fn_zone *fz)
{
        return dst & FZ_MASK(fz);
}

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);

        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_rcu(&f->fn_hash);

                        new_head = rcu_dereference_protected(fz->fz_hash, 1) +
                                   fn_hash(f->fn_key, fz);
                        hlist_add_head_rcu(&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;

        new_divisor = old_divisor = fz->fz_divisor;

        switch (old_divisor) {
        case EMBEDDED_HASH_SIZE:
                new_divisor *= EMBEDDED_HASH_SIZE;
                break;
        case EMBEDDED_HASH_SIZE*EMBEDDED_HASH_SIZE:
                new_divisor *= (EMBEDDED_HASH_SIZE/2);
                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) {
                struct fn_zone nfz;

                memcpy(&nfz, fz, sizeof(nfz));

                write_seqlock_bh(&fz->fz_lock);
                old_ht = rcu_dereference_protected(fz->fz_hash, 1);
                RCU_INIT_POINTER(nfz.fz_hash, ht);
                nfz.fz_hashmask = new_hashmask;
                nfz.fz_divisor = new_divisor;
                fn_rebuild_zone(&nfz, old_ht, old_divisor);
                fib_hash_genid++;
                rcu_assign_pointer(fz->fz_hash, ht);
                fz->fz_hashmask = new_hashmask;
                fz->fz_divisor = new_divisor;
                write_sequnlock_bh(&fz->fz_lock);

                if (old_ht != fz->fz_embedded_hash) {
                        synchronize_rcu();
                        fz_hash_free(old_ht, old_divisor);
                }
        }
}

static void fn_free_node_rcu(struct rcu_head *head)
{
        struct fib_node *f = container_of(head, struct fib_node, fn_embedded_alias.rcu);

        kmem_cache_free(fn_hash_kmem, f);
}

static inline void fn_free_node(struct fib_node *f)
{
        call_rcu(&f->fn_embedded_alias.rcu, fn_free_node_rcu);
}

static void fn_free_alias_rcu(struct rcu_head *head)
{
        struct fib_alias *fa = container_of(head, struct fib_alias, rcu);

        kmem_cache_free(fn_alias_kmem, fa);
}

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
                call_rcu(&fa->rcu, fn_free_alias_rcu);
}

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;

        seqlock_init(&fz->fz_lock);
        fz->fz_divisor = z ? EMBEDDED_HASH_SIZE : 1;
        fz->fz_hashmask = fz->fz_divisor - 1;
        RCU_INIT_POINTER(fz->fz_hash, fz->fz_embedded_hash);
        fz->fz_order = z;
        fz->fz_revorder = 32 - 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;
        if (i > 32) {
                /* No more specific masks, we are the first. */
                rcu_assign_pointer(fz->fz_next,
                                   rtnl_dereference(table->fn_zone_list));
                rcu_assign_pointer(table->fn_zone_list, fz);
        } else {
                rcu_assign_pointer(fz->fz_next,
                                   rtnl_dereference(table->fn_zones[i]->fz_next));
                rcu_assign_pointer(table->fn_zones[i]->fz_next, fz);
        }
        table->fn_zones[z] = fz;
        fib_hash_genid++;
        return fz;
}

int fib_table_lookup(struct fib_table *tb,
                     const struct flowi *flp, struct fib_result *res,
                     int fib_flags)
{
        int err;
        struct fn_zone *fz;
        struct fn_hash *t = (struct fn_hash *)tb->tb_data;

        rcu_read_lock();
        for (fz = rcu_dereference(t->fn_zone_list);
             fz != NULL;
             fz = rcu_dereference(fz->fz_next)) {
                struct hlist_head *head;
                struct hlist_node *node;
                struct fib_node *f;
                __be32 k;
                unsigned int seq;

                do {
                        seq = read_seqbegin(&fz->fz_lock);
                        k = fz_key(flp->fl4_dst, fz);

                        head = rcu_dereference(fz->fz_hash) + fn_hash(k, fz);
                        hlist_for_each_entry_rcu(f, node, head, fn_hash) {
                                if (f->fn_key != k)
                                        continue;

                                err = fib_semantic_match(&f->fn_alias,
                                                 flp, res,
                                                 fz->fz_order, fib_flags);
                                if (err <= 0)
                                        goto out;
                        }
                } while (read_seqretry(&fz->fz_lock, seq));
        }
        err = 1;
out:
        rcu_read_unlock();
        return err;
}

void fib_table_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];
        struct hlist_head *head;

        if (fz == NULL)
                return;

        last_idx = -1;
        last_resort = NULL;
        order = -1;

        rcu_read_lock();
        head = rcu_dereference(fz->fz_hash);
        hlist_for_each_entry_rcu(f, node, head, fn_hash) {
                struct fib_alias *fa;

                list_for_each_entry_rcu(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;

                        fib_alias_accessed(fa);

                        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:
        rcu_read_unlock();
}

/* Insert node F to FZ. */
static inline void fib_insert_node(struct fn_zone *fz, struct fib_node *f)
{
        struct hlist_head *head = rtnl_dereference(fz->fz_hash) + fn_hash(f->fn_key, fz);

        hlist_add_head_rcu(&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 = rtnl_dereference(fz->fz_hash) + fn_hash(key, fz);
        struct hlist_node *node;
        struct fib_node *f;

        hlist_for_each_entry_rcu(f, node, head, fn_hash) {
                if (f->fn_key == key)
                        return f;
        }

        return NULL;
}


static struct fib_alias *fib_fast_alloc(struct fib_node *f)
{
        struct fib_alias *fa = &f->fn_embedded_alias;

        if (fa->fa_info != NULL)
                fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
        return fa;
}

/* Caller must hold RTNL. */
int fib_table_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) {
                        u8 state;

                        fa = fa_first;
                        if (fa_match) {
                                if (fa == fa_match)
                                        err = 0;
                                goto out;
                        }
                        err = -ENOBUFS;
                        new_fa = fib_fast_alloc(f);
                        if (new_fa == NULL)
                                goto out;

                        new_fa->fa_tos = fa->fa_tos;
                        new_fa->fa_info = fi;
                        new_fa->fa_type = cfg->fc_type;
                        new_fa->fa_scope = cfg->fc_scope;
                        state = fa->fa_state;
                        new_fa->fa_state = state & ~FA_S_ACCESSED;
                        fib_hash_genid++;
                        list_replace_rcu(&fa->fa_list, &new_fa->fa_list);

                        fn_free_alias(fa, f);
                        if (state & FA_S_ACCESSED)
                                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, 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 = fib_fast_alloc(f);
        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.
         */

        if (new_f)
                fib_insert_node(fz, new_f);
        list_add_tail_rcu(&new_fa->fa_list,
                 (fa ? &fa->fa_list : &f->fn_alias));
        fib_hash_genid++;

        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;
}

int fib_table_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;
                list_del_rcu(&fa->fa_list);
                if (list_empty(&f->fn_alias)) {
                        hlist_del_rcu(&f->fn_hash);
                        kill_fn = 1;
                }
                fib_hash_genid++;

                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 = rtnl_dereference(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)) {
                                list_del_rcu(&fa->fa_list);
                                if (list_empty(&f->fn_alias)) {
                                        hlist_del_rcu(&f->fn_hash);
                                        kill_f = 1;
                                }
                                fib_hash_genid++;

                                fn_free_alias(fa, f);
                                found++;
                        }
                }
                if (kill_f) {
                        fn_free_node(f);
                        fz->fz_nent--;
                }
        }
        return found;
}

/* caller must hold RTNL. */
int fib_table_flush(struct fib_table *tb)
{
        struct fn_hash *table = (struct fn_hash *) tb->tb_data;
        struct fn_zone *fz;
        int found = 0;

        for (fz = rtnl_dereference(table->fn_zone_list);
             fz != NULL;
             fz = rtnl_dereference(fz->fz_next)) {
                int i;

                for (i = fz->fz_divisor - 1; i >= 0; i--)
                        found += fn_flush_list(fz, i);
        }
        return found;
}

void fib_free_table(struct fib_table *tb)
{
        struct fn_hash *table = (struct fn_hash *) tb->tb_data;
        struct fn_zone *fz, *next;

        next = table->fn_zone_list;
        while (next != NULL) {
                fz = next;
                next = fz->fz_next;

                if (fz->fz_hash != fz->fz_embedded_hash)
                        fz_hash_free(fz->fz_hash, fz->fz_divisor);

                kfree(fz);
        }

        kfree(tb);
}

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_rcu(f, node, head, fn_hash) {
                struct fib_alias *fa;

                list_for_each_entry_rcu(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;
        struct hlist_head *head = rcu_dereference(fz->fz_hash);

        if (head == NULL)
                return skb->len;
        s_h = cb->args[3];
        for (h = s_h; h < fz->fz_divisor; h++) {
                if (hlist_empty(head + h))
                        continue;
                if (fn_hash_dump_bucket(skb, cb, tb, fz, head + 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;
}

int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
                   struct netlink_callback *cb)
{
        int m = 0, s_m;
        struct fn_zone *fz;
        struct fn_hash *table = (struct fn_hash *)tb->tb_data;

        s_m = cb->args[2];
        rcu_read_lock();
        for (fz = rcu_dereference(table->fn_zone_list);
             fz != NULL;
             fz = rcu_dereference(fz->fz_next), m++) {
                if (m < s_m)
                        continue;
                if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
                        cb->args[2] = m;
                        rcu_read_unlock();
                        return -1;
                }
                memset(&cb->args[3], 0,
                       sizeof(cb->args) - 3*sizeof(cb->args[0]));
        }
        rcu_read_unlock();
        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;

        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 = rcu_dereference(table->fn_zone_list);
             iter->zone != NULL;
             iter->zone = rcu_dereference(iter->zone->fz_next)) {
                int maxslot;

                if (!iter->zone->fz_nent)
                        continue;

                iter->hash_head = rcu_dereference(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 = rcu_dereference(iter->zone->fz_next);

                if (!iter->zone)
                        goto out;

                iter->bucket = 0;
                iter->hash_head = rcu_dereference(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(RCU)
{
        void *v = NULL;

        rcu_read_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(RCU)
{
        rcu_read_unlock();
}

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 */