path: root/net/decnet/dn_table.c

/*
 * 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/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