dn_table.c

linux 内核源代码

			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)
{
	unsigned int h, s_h;
	unsigned int e = 0, s_e;
	struct dn_fib_table *tb;
	struct hlist_node *node;
	int dumped = 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);
}