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root/net/decnet/dn_table.c

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DEFINITIONS

This source file includes following definitions.
  1. dn_hash
  2. dz_key
  3. dn_chain_p
  4. dz_chain
  5. dn_key_eq
  6. dn_key_leq
  7. dn_rebuild_zone
  8. dn_rehash_zone
  9. dn_free_node
  10. dn_new_zone
  11. dn_fib_nh_match
  12. dn_fib_nlmsg_size
  13. dn_fib_dump_info
  14. dn_rtmsg_fib
  15. dn_hash_dump_bucket
  16. dn_hash_dump_zone
  17. dn_fib_table_dump
  18. dn_fib_dump
  19. dn_fib_table_insert
  20. dn_fib_table_delete
  21. dn_flush_list
  22. dn_fib_table_flush
  23. dn_fib_table_lookup
  24. dn_fib_get_table
  25. dn_fib_empty_table
  26. dn_fib_flush
  27. dn_fib_table_init
  28. dn_fib_table_cleanup

/*
 * DECnet       An implementation of the DECnet protocol suite for the LINUX
 *              operating system.  DECnet is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              DECnet Routing Forwarding Information Base (Routing Tables)
 *
 * Author:      Steve Whitehouse <SteveW@ACM.org>
 *              Mostly copied from the IPv4 routing code
 *
 *
 * Changes:
 *
 */
#include <linux/string.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/netdevice.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#include <linux/route.h> /* RTF_xxx */
#include <net/neighbour.h>
#include <net/netlink.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/fib_rules.h>
#include <net/dn.h>
#include <net/dn_route.h>
#include <net/dn_fib.h>
#include <net/dn_neigh.h>
#include <net/dn_dev.h>

struct dn_zone
{
        struct dn_zone          *dz_next;
        struct dn_fib_node      **dz_hash;
        int                     dz_nent;
        int                     dz_divisor;
        u32                     dz_hashmask;
#define DZ_HASHMASK(dz) ((dz)->dz_hashmask)
        int                     dz_order;
        __le16                  dz_mask;
#define DZ_MASK(dz)     ((dz)->dz_mask)
};

struct dn_hash
{
        struct dn_zone  *dh_zones[17];
        struct dn_zone  *dh_zone_list;
};

#define dz_key_0(key)           ((key).datum = 0)
#define dz_prefix(key,dz)       ((key).datum)

#define for_nexthops(fi) { int nhsel; const struct dn_fib_nh *nh;\
        for(nhsel = 0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)

#define endfor_nexthops(fi) }

#define DN_MAX_DIVISOR 1024
#define DN_S_ZOMBIE 1
#define DN_S_ACCESSED 2

#define DN_FIB_SCAN(f, fp) \
for( ; ((f) = *(fp)) != NULL; (fp) = &(f)->fn_next)

#define DN_FIB_SCAN_KEY(f, fp, key) \
for( ; ((f) = *(fp)) != NULL && dn_key_eq((f)->fn_key, (key)); (fp) = &(f)->fn_next)

#define RT_TABLE_MIN 1
#define DN_FIB_TABLE_HASHSZ 256
static struct hlist_head dn_fib_table_hash[DN_FIB_TABLE_HASHSZ];
static DEFINE_RWLOCK(dn_fib_tables_lock);

static struct kmem_cache *dn_hash_kmem __read_mostly;
static int dn_fib_hash_zombies;

static inline dn_fib_idx_t dn_hash(dn_fib_key_t key, struct dn_zone *dz)
{
        u16 h = dn_ntohs(key.datum)>>(16 - dz->dz_order);
        h ^= (h >> 10);
        h ^= (h >> 6);
        h &= DZ_HASHMASK(dz);
        return *(dn_fib_idx_t *)&h;
}

static inline dn_fib_key_t dz_key(__le16 dst, struct dn_zone *dz)
{
        dn_fib_key_t k;
        k.datum = dst & DZ_MASK(dz);
        return k;
}

static inline struct dn_fib_node **dn_chain_p(dn_fib_key_t key, struct dn_zone *dz)
{
        return &dz->dz_hash[dn_hash(key, dz).datum];
}

static inline struct dn_fib_node *dz_chain(dn_fib_key_t key, struct dn_zone *dz)
{
        return dz->dz_hash[dn_hash(key, dz).datum];
}

static inline int dn_key_eq(dn_fib_key_t a, dn_fib_key_t b)
{
        return a.datum == b.datum;
}

static inline int dn_key_leq(dn_fib_key_t a, dn_fib_key_t b)
{
        return a.datum <= b.datum;
}

static inline void dn_rebuild_zone(struct dn_zone *dz,
                                   struct dn_fib_node **old_ht,
                                   int old_divisor)
{
        int i;
        struct dn_fib_node *f, **fp, *next;

        for(i = 0; i < old_divisor; i++) {
                for(f = old_ht[i]; f; f = f->fn_next) {
                        next = f->fn_next;
                        for(fp = dn_chain_p(f->fn_key, dz);
                                *fp && dn_key_leq((*fp)->fn_key, f->fn_key);
                                fp = &(*fp)->fn_next)
                                /* NOTHING */;
                        f->fn_next = *fp;
                        *fp = f;
                }
        }
}

static void dn_rehash_zone(struct dn_zone *dz)
{
        struct dn_fib_node **ht, **old_ht;
        int old_divisor, new_divisor;
        u32 new_hashmask;

        old_divisor = dz->dz_divisor;

        switch(old_divisor) {
                case 16:
                        new_divisor = 256;
                        new_hashmask = 0xFF;
                        break;
                default:
                        printk(KERN_DEBUG "DECnet: dn_rehash_zone: BUG! %d\n", old_divisor);
                case 256:
                        new_divisor = 1024;
                        new_hashmask = 0x3FF;
                        break;
        }

        ht = kcalloc(new_divisor, sizeof(struct dn_fib_node*), GFP_KERNEL);
        if (ht == NULL)
                return;

        write_lock_bh(&dn_fib_tables_lock);
        old_ht = dz->dz_hash;
        dz->dz_hash = ht;
        dz->dz_hashmask = new_hashmask;
        dz->dz_divisor = new_divisor;
        dn_rebuild_zone(dz, old_ht, old_divisor);
        write_unlock_bh(&dn_fib_tables_lock);
        kfree(old_ht);
}

static void dn_free_node(struct dn_fib_node *f)
{
        dn_fib_release_info(DN_FIB_INFO(f));
        kmem_cache_free(dn_hash_kmem, f);
}


static struct dn_zone *dn_new_zone(struct dn_hash *table, int z)
{
        int i;
        struct dn_zone *dz = kzalloc(sizeof(struct dn_zone), GFP_KERNEL);
        if (!dz)
                return NULL;

        if (z) {
                dz->dz_divisor = 16;
                dz->dz_hashmask = 0x0F;
        } else {
                dz->dz_divisor = 1;
                dz->dz_hashmask = 0;
        }

        dz->dz_hash = kcalloc(dz->dz_divisor, sizeof(struct dn_fib_node *), GFP_KERNEL);
        if (!dz->dz_hash) {
                kfree(dz);
                return NULL;
        }

        dz->dz_order = z;
        dz->dz_mask = dnet_make_mask(z);

        for(i = z + 1; i <= 16; i++)
                if (table->dh_zones[i])
                        break;

        write_lock_bh(&dn_fib_tables_lock);
        if (i>16) {
                dz->dz_next = table->dh_zone_list;
                table->dh_zone_list = dz;
        } else {
                dz->dz_next = table->dh_zones[i]->dz_next;
                table->dh_zones[i]->dz_next = dz;
        }
        table->dh_zones[z] = dz;
        write_unlock_bh(&dn_fib_tables_lock);
        return dz;
}


static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern_rta *rta, struct dn_fib_info *fi)
{
        struct rtnexthop *nhp;
        int nhlen;

        if (rta->rta_priority && *rta->rta_priority != fi->fib_priority)
                return 1;

        if (rta->rta_oif || rta->rta_gw) {
                if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
                    (!rta->rta_gw  || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 2) == 0))
                        return 0;
                return 1;
        }

        if (rta->rta_mp == NULL)
                return 0;

        nhp = RTA_DATA(rta->rta_mp);
        nhlen = RTA_PAYLOAD(rta->rta_mp);

        for_nexthops(fi) {
                int attrlen = nhlen - sizeof(struct rtnexthop);
                __le16 gw;

                if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
                        return -EINVAL;
                if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
                        return 1;
                if (attrlen) {
                        gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);

                        if (gw && gw != nh->nh_gw)
                                return 1;
                }
                nhp = RTNH_NEXT(nhp);
        } endfor_nexthops(fi);

        return 0;
}

static inline size_t dn_fib_nlmsg_size(struct dn_fib_info *fi)
{
        size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
                         + nla_total_size(4) /* RTA_TABLE */
                         + nla_total_size(2) /* RTA_DST */
                         + nla_total_size(4); /* RTA_PRIORITY */

        /* space for nested metrics */
        payload += nla_total_size((RTAX_MAX * nla_total_size(4)));

        if (fi->fib_nhs) {
                /* Also handles the special case fib_nhs == 1 */

                /* each nexthop is packed in an attribute */
                size_t nhsize = nla_total_size(sizeof(struct rtnexthop));

                /* may contain a gateway attribute */
                nhsize += nla_total_size(4);

                /* all nexthops are packed in a nested attribute */
                payload += nla_total_size(fi->fib_nhs * nhsize);
        }

        return payload;
}

static int dn_fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
                        u32 tb_id, u8 type, u8 scope, void *dst, int dst_len,
                        struct dn_fib_info *fi, unsigned int flags)
{
        struct rtmsg *rtm;
        struct nlmsghdr *nlh;
        unsigned char *b = skb_tail_pointer(skb);

        nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
        rtm = NLMSG_DATA(nlh);
        rtm->rtm_family = AF_DECnet;
        rtm->rtm_dst_len = dst_len;
        rtm->rtm_src_len = 0;
        rtm->rtm_tos = 0;
        rtm->rtm_table = tb_id;
        RTA_PUT_U32(skb, RTA_TABLE, tb_id);
        rtm->rtm_flags = fi->fib_flags;
        rtm->rtm_scope = scope;
        rtm->rtm_type  = type;
        if (rtm->rtm_dst_len)
                RTA_PUT(skb, RTA_DST, 2, dst);
        rtm->rtm_protocol = fi->fib_protocol;
        if (fi->fib_priority)
                RTA_PUT(skb, RTA_PRIORITY, 4, &fi->fib_priority);
        if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
                goto rtattr_failure;
        if (fi->fib_nhs == 1) {
                if (fi->fib_nh->nh_gw)
                        RTA_PUT(skb, RTA_GATEWAY, 2, &fi->fib_nh->nh_gw);
                if (fi->fib_nh->nh_oif)
                        RTA_PUT(skb, RTA_OIF, sizeof(int), &fi->fib_nh->nh_oif);
        }
        if (fi->fib_nhs > 1) {
                struct rtnexthop *nhp;
                struct rtattr *mp_head;
                if (skb_tailroom(skb) <= RTA_SPACE(0))
                        goto rtattr_failure;
                mp_head = (struct rtattr *)skb_put(skb, RTA_SPACE(0));

                for_nexthops(fi) {
                        if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
                                goto rtattr_failure;
                        nhp = (struct rtnexthop *)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
                        nhp->rtnh_flags = nh->nh_flags & 0xFF;
                        nhp->rtnh_hops = nh->nh_weight - 1;
                        nhp->rtnh_ifindex = nh->nh_oif;
                        if (nh->nh_gw)
                                RTA_PUT(skb, RTA_GATEWAY, 2, &nh->nh_gw);
                        nhp->rtnh_len = skb_tail_pointer(skb) - (unsigned char *)nhp;
                } endfor_nexthops(fi);
                mp_head->rta_type = RTA_MULTIPATH;
                mp_head->rta_len = skb_tail_pointer(skb) - (u8 *)mp_head;
        }

        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
        return skb->len;


nlmsg_failure:
rtattr_failure:
        nlmsg_trim(skb, b);
        return -EMSGSIZE;
}


static void dn_rtmsg_fib(int event, struct dn_fib_node *f, int z, u32 tb_id,
                        struct nlmsghdr *nlh, struct netlink_skb_parms *req)
{
        struct sk_buff *skb;
        u32 pid = req ? req->pid : 0;
        int err = -ENOBUFS;

        skb = nlmsg_new(dn_fib_nlmsg_size(DN_FIB_INFO(f)), GFP_KERNEL);
        if (skb == NULL)
                goto errout;

        err = dn_fib_dump_info(skb, pid, nlh->nlmsg_seq, event, tb_id,
                               f->fn_type, f->fn_scope, &f->fn_key, z,
                               DN_FIB_INFO(f), 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in dn_fib_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_notify(skb, &init_net, pid, RTNLGRP_DECnet_ROUTE, nlh, GFP_KERNEL);
errout:
        if (err < 0)
                rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_ROUTE, err);
}

static __inline__ int dn_hash_dump_bucket(struct sk_buff *skb,
                                struct netlink_callback *cb,
                                struct dn_fib_table *tb,
                                struct dn_zone *dz,
                                struct dn_fib_node *f)
{
        int i, s_i;

        s_i = cb->args[4];
        for(i = 0; f; i++, f = f->fn_next) {
                if (i < s_i)
                        continue;
                if (f->fn_state & DN_S_ZOMBIE)
                        continue;
                if (dn_fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
                                cb->nlh->nlmsg_seq,
                                RTM_NEWROUTE,
                                tb->n,
                                (f->fn_state & DN_S_ZOMBIE) ? 0 : f->fn_type,
                                f->fn_scope, &f->fn_key, dz->dz_order,
                                f->fn_info, NLM_F_MULTI) < 0) {
                        cb->args[4] = i;
                        return -1;
                }
        }
        cb->args[4] = i;
        return skb->len;
}

static __inline__ int dn_hash_dump_zone(struct sk_buff *skb,
                                struct netlink_callback *cb,
                                struct dn_fib_table *tb,
                                struct dn_zone *dz)
{
        int h, s_h;

        s_h = cb->args[3];
        for(h = 0; h < dz->dz_divisor; h++) {
                if (h < s_h)
                        continue;
                if (h > s_h)
                        memset(&cb->args[4], 0, sizeof(cb->args) - 4*sizeof(cb->args[0]));
                if (dz->dz_hash == NULL || dz->dz_hash[h] == NULL)
                        continue;
                if (dn_hash_dump_bucket(skb, cb, tb, dz, dz->dz_hash[h]) < 0) {
                        cb->args[3] = h;
                        return -1;
                }
        }
        cb->args[3] = h;
        return skb->len;
}

static int dn_fib_table_dump(struct dn_fib_table *tb, struct sk_buff *skb,
                                struct netlink_callback *cb)
{
        int m, s_m;
        struct dn_zone *dz;
        struct dn_hash *table = (struct dn_hash *)tb->data;

        s_m = cb->args[2];
        read_lock(&dn_fib_tables_lock);
        for(dz = table->dh_zone_list, m = 0; dz; dz = dz->dz_next, m++) {
                if (m < s_m)
                        continue;
                if (m > s_m)
                        memset(&cb->args[3], 0, sizeof(cb->args) - 3*sizeof(cb->args[0]));

                if (dn_hash_dump_zone(skb, cb, tb, dz) < 0) {
                        cb->args[2] = m;
                        read_unlock(&dn_fib_tables_lock);
                        return -1;
                }
        }
        read_unlock(&dn_fib_tables_lock);
        cb->args[2] = m;

        return skb->len;
}

int dn_fib_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        unsigned int h, s_h;
        unsigned int e = 0, s_e;
        struct dn_fib_table *tb;
        struct hlist_node *node;
        int dumped = 0;

        if (net != &init_net)
                return 0;

        if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&
                ((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)
                        return dn_cache_dump(skb, cb);

        s_h = cb->args[0];
        s_e = cb->args[1];

        for (h = s_h; h < DN_FIB_TABLE_HASHSZ; h++, s_h = 0) {
                e = 0;
                hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist) {
                        if (e < s_e)
                                goto next;
                        if (dumped)
                                memset(&cb->args[2], 0, sizeof(cb->args) -
                                                 2 * sizeof(cb->args[0]));
                        if (tb->dump(tb, skb, cb) < 0)
                                goto out;
                        dumped = 1;
next:
                        e++;
                }
        }
out:
        cb->args[1] = e;
        cb->args[0] = h;

        return skb->len;
}

static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
{
        struct dn_hash *table = (struct dn_hash *)tb->data;
        struct dn_fib_node *new_f, *f, **fp, **del_fp;
        struct dn_zone *dz;
        struct dn_fib_info *fi;
        int z = r->rtm_dst_len;
        int type = r->rtm_type;
        dn_fib_key_t key;
        int err;

        if (z > 16)
                return -EINVAL;

        dz = table->dh_zones[z];
        if (!dz && !(dz = dn_new_zone(table, z)))
                return -ENOBUFS;

        dz_key_0(key);
        if (rta->rta_dst) {
                __le16 dst;
                memcpy(&dst, rta->rta_dst, 2);
                if (dst & ~DZ_MASK(dz))
                        return -EINVAL;
                key = dz_key(dst, dz);
        }

        if ((fi = dn_fib_create_info(r, rta, n, &err)) == NULL)
                return err;

        if (dz->dz_nent > (dz->dz_divisor << 2) &&
                        dz->dz_divisor > DN_MAX_DIVISOR &&
                        (z==16 || (1<<z) > dz->dz_divisor))
                dn_rehash_zone(dz);

        fp = dn_chain_p(key, dz);

        DN_FIB_SCAN(f, fp) {
                if (dn_key_leq(key, f->fn_key))
                        break;
        }

        del_fp = NULL;

        if (f && (f->fn_state & DN_S_ZOMBIE) &&
                        dn_key_eq(f->fn_key, key)) {
                del_fp = fp;
                fp = &f->fn_next;
                f = *fp;
                goto create;
        }

        DN_FIB_SCAN_KEY(f, fp, key) {
                if (fi->fib_priority <= DN_FIB_INFO(f)->fib_priority)
                        break;
        }

        if (f && dn_key_eq(f->fn_key, key) &&
                        fi->fib_priority == DN_FIB_INFO(f)->fib_priority) {
                struct dn_fib_node **ins_fp;

                err = -EEXIST;
                if (n->nlmsg_flags & NLM_F_EXCL)
                        goto out;

                if (n->nlmsg_flags & NLM_F_REPLACE) {
                        del_fp = fp;
                        fp = &f->fn_next;
                        f = *fp;
                        goto replace;
                }

                ins_fp = fp;
                err = -EEXIST;

                DN_FIB_SCAN_KEY(f, fp, key) {
                        if (fi->fib_priority != DN_FIB_INFO(f)->fib_priority)
                                break;
                        if (f->fn_type == type && f->fn_scope == r->rtm_scope
                                        && DN_FIB_INFO(f) == fi)
                                goto out;
                }

                if (!(n->nlmsg_flags & NLM_F_APPEND)) {
                        fp = ins_fp;
                        f = *fp;
                }
        }

create:
        err = -ENOENT;
        if (!(n->nlmsg_flags & NLM_F_CREATE))
                goto out;

replace:
        err = -ENOBUFS;
        new_f = kmem_cache_zalloc(dn_hash_kmem, GFP_KERNEL);
        if (new_f == NULL)
                goto out;

        new_f->fn_key = key;
        new_f->fn_type = type;
        new_f->fn_scope = r->rtm_scope;
        DN_FIB_INFO(new_f) = fi;

        new_f->fn_next = f;
        write_lock_bh(&dn_fib_tables_lock);
        *fp = new_f;
        write_unlock_bh(&dn_fib_tables_lock);
        dz->dz_nent++;

        if (del_fp) {
                f = *del_fp;
                write_lock_bh(&dn_fib_tables_lock);
                *del_fp = f->fn_next;
                write_unlock_bh(&dn_fib_tables_lock);

                if (!(f->fn_state & DN_S_ZOMBIE))
                        dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);
                if (f->fn_state & DN_S_ACCESSED)
                        dn_rt_cache_flush(-1);
                dn_free_node(f);
                dz->dz_nent--;
        } else {
                dn_rt_cache_flush(-1);
        }

        dn_rtmsg_fib(RTM_NEWROUTE, new_f, z, tb->n, n, req);

        return 0;
out:
        dn_fib_release_info(fi);
        return err;
}


static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
{
        struct dn_hash *table = (struct dn_hash*)tb->data;
        struct dn_fib_node **fp, **del_fp, *f;
        int z = r->rtm_dst_len;
        struct dn_zone *dz;
        dn_fib_key_t key;
        int matched;


        if (z > 16)
                return -EINVAL;

        if ((dz = table->dh_zones[z]) == NULL)
                return -ESRCH;

        dz_key_0(key);
        if (rta->rta_dst) {
                __le16 dst;
                memcpy(&dst, rta->rta_dst, 2);
                if (dst & ~DZ_MASK(dz))
                        return -EINVAL;
                key = dz_key(dst, dz);
        }

        fp = dn_chain_p(key, dz);

        DN_FIB_SCAN(f, fp) {
                if (dn_key_eq(f->fn_key, key))
                        break;
                if (dn_key_leq(key, f->fn_key))
                        return -ESRCH;
        }

        matched = 0;
        del_fp = NULL;
        DN_FIB_SCAN_KEY(f, fp, key) {
                struct dn_fib_info *fi = DN_FIB_INFO(f);

                if (f->fn_state & DN_S_ZOMBIE)
                        return -ESRCH;

                matched++;

                if (del_fp == NULL &&
                                (!r->rtm_type || f->fn_type == r->rtm_type) &&
                                (r->rtm_scope == RT_SCOPE_NOWHERE || f->fn_scope == r->rtm_scope) &&
                                (!r->rtm_protocol ||
                                        fi->fib_protocol == r->rtm_protocol) &&
                                dn_fib_nh_match(r, n, rta, fi) == 0)
                        del_fp = fp;
        }

        if (del_fp) {
                f = *del_fp;
                dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);

                if (matched != 1) {
                        write_lock_bh(&dn_fib_tables_lock);
                        *del_fp = f->fn_next;
                        write_unlock_bh(&dn_fib_tables_lock);

                        if (f->fn_state & DN_S_ACCESSED)
                                dn_rt_cache_flush(-1);
                        dn_free_node(f);
                        dz->dz_nent--;
                } else {
                        f->fn_state |= DN_S_ZOMBIE;
                        if (f->fn_state & DN_S_ACCESSED) {
                                f->fn_state &= ~DN_S_ACCESSED;
                                dn_rt_cache_flush(-1);
                        }
                        if (++dn_fib_hash_zombies > 128)
                                dn_fib_flush();
                }

                return 0;
        }

        return -ESRCH;
}

static inline int dn_flush_list(struct dn_fib_node **fp, int z, struct dn_hash *table)
{
        int found = 0;
        struct dn_fib_node *f;

        while((f = *fp) != NULL) {
                struct dn_fib_info *fi = DN_FIB_INFO(f);

                if (fi && ((f->fn_state & DN_S_ZOMBIE) || (fi->fib_flags & RTNH_F_DEAD))) {
                        write_lock_bh(&dn_fib_tables_lock);
                        *fp = f->fn_next;
                        write_unlock_bh(&dn_fib_tables_lock);

                        dn_free_node(f);
                        found++;
                        continue;
                }
                fp = &f->fn_next;
        }

        return found;
}

static int dn_fib_table_flush(struct dn_fib_table *tb)
{
        struct dn_hash *table = (struct dn_hash *)tb->data;
        struct dn_zone *dz;
        int found = 0;

        dn_fib_hash_zombies = 0;
        for(dz = table->dh_zone_list; dz; dz = dz->dz_next) {
                int i;
                int tmp = 0;
                for(i = dz->dz_divisor-1; i >= 0; i--)
                        tmp += dn_flush_list(&dz->dz_hash[i], dz->dz_order, table);
                dz->dz_nent -= tmp;
                found += tmp;
        }

        return found;
}

static int dn_fib_table_lookup(struct dn_fib_table *tb, const struct flowi *flp, struct dn_fib_res *res)
{
        int err;
        struct dn_zone *dz;
        struct dn_hash *t = (struct dn_hash *)tb->data;

        read_lock(&dn_fib_tables_lock);
        for(dz = t->dh_zone_list; dz; dz = dz->dz_next) {
                struct dn_fib_node *f;
                dn_fib_key_t k = dz_key(flp->fld_dst, dz);

                for(f = dz_chain(k, dz); f; f = f->fn_next) {
                        if (!dn_key_eq(k, f->fn_key)) {
                                if (dn_key_leq(k, f->fn_key))
                                        break;
                                else
                                        continue;
                        }

                        f->fn_state |= DN_S_ACCESSED;

                        if (f->fn_state&DN_S_ZOMBIE)
                                continue;

                        if (f->fn_scope < flp->fld_scope)
                                continue;

                        err = dn_fib_semantic_match(f->fn_type, DN_FIB_INFO(f), flp, res);

                        if (err == 0) {
                                res->type = f->fn_type;
                                res->scope = f->fn_scope;
                                res->prefixlen = dz->dz_order;
                                goto out;
                        }
                        if (err < 0)
                                goto out;
                }
        }
        err = 1;
out:
        read_unlock(&dn_fib_tables_lock);
        return err;
}


struct dn_fib_table *dn_fib_get_table(u32 n, int create)
{
        struct dn_fib_table *t;
        struct hlist_node *node;
        unsigned int h;

        if (n < RT_TABLE_MIN)
                return NULL;

        if (n > RT_TABLE_MAX)
                return NULL;

        h = n & (DN_FIB_TABLE_HASHSZ - 1);
        rcu_read_lock();
        hlist_for_each_entry_rcu(t, node, &dn_fib_table_hash[h], hlist) {
                if (t->n == n) {
                        rcu_read_unlock();
                        return t;
                }
        }
        rcu_read_unlock();

        if (!create)
                return NULL;

        if (in_interrupt() && net_ratelimit()) {
                printk(KERN_DEBUG "DECnet: BUG! Attempt to create routing table from interrupt\n");
                return NULL;
        }

        t = kzalloc(sizeof(struct dn_fib_table) + sizeof(struct dn_hash),
                    GFP_KERNEL);
        if (t == NULL)
                return NULL;

        t->n = n;
        t->insert = dn_fib_table_insert;
        t->delete = dn_fib_table_delete;
        t->lookup = dn_fib_table_lookup;
        t->flush  = dn_fib_table_flush;
        t->dump = dn_fib_table_dump;
        hlist_add_head_rcu(&t->hlist, &dn_fib_table_hash[h]);

        return t;
}

struct dn_fib_table *dn_fib_empty_table(void)
{
        u32 id;

        for(id = RT_TABLE_MIN; id <= RT_TABLE_MAX; id++)
                if (dn_fib_get_table(id, 0) == NULL)
                        return dn_fib_get_table(id, 1);
        return NULL;
}

void dn_fib_flush(void)
{
        int flushed = 0;
        struct dn_fib_table *tb;
        struct hlist_node *node;
        unsigned int h;

        for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
                hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist)
                        flushed += tb->flush(tb);
        }

        if (flushed)
                dn_rt_cache_flush(-1);
}

void __init dn_fib_table_init(void)
{
        dn_hash_kmem = kmem_cache_create("dn_fib_info_cache",
                                        sizeof(struct dn_fib_info),
                                        0, SLAB_HWCACHE_ALIGN,
                                        NULL);
}

void __exit dn_fib_table_cleanup(void)
{
        struct dn_fib_table *t;
        struct hlist_node *node, *next;
        unsigned int h;

        write_lock(&dn_fib_tables_lock);
        for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
                hlist_for_each_entry_safe(t, node, next, &dn_fib_table_hash[h],
                                          hlist) {
                        hlist_del(&t->hlist);
                        kfree(t);
                }
        }
        write_unlock(&dn_fib_tables_lock);
}

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