dn_table.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

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

	dz_key_0(key);
	if (rta->rta_dst) {
		dn_address 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_alloc(dn_hash_kmem, SLAB_KERNEL);
	if (new_f == NULL)
		goto out;

	memset(new_f, 0, sizeof(struct dn_fib_node));

	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) {
		dn_address 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 dn_fib_key *
key, 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(key->dst, dz);

		for(f = dz_chain(k, dz); f; f = f->fn_next) {
			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 < key->scope)
				continue;

			err = dn_fib_semantic_match(f->fn_type, DN_FIB_INFO(f), key, 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;
}

#ifdef CONFIG_PROC_FS

static unsigned dn_fib_flag_trans(int type, int dead, u16 mask, struct dn_fib_info *fi)
{
	static unsigned type2flags[RTN_MAX+1] = {
		0, 0, 0, 0, 0, 0, 0, RTF_REJECT, RTF_REJECT, 0, 0, 0
	};
	unsigned flags = type2flags[type];

	if (fi && fi->fib_nh->nh_gw)
		flags |= RTF_GATEWAY;
	if (mask == 0xFFFF)
		flags |= RTF_HOST;
	if (dead)
		flags |= RTF_UP;
	return flags;
}

static void dn_fib_node_get_info(int type, int dead, struct dn_fib_info *fi, u16 prefix, u16 mask, char *buffer)
{
	int len;
	unsigned flags = dn_fib_flag_trans(type, dead, mask, fi);

	if (fi) {
		len = sprintf(buffer, "%s\t%04x\t%04x\t%04x\t%d\t%u\t%d\t%04x\t%d\t%u\t%u",
				fi->fib_dev ? fi->fib_dev->name : "*", prefix,
				fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
				mask, 0, 0, 0);
	} else {
		len = sprintf(buffer, "*\t%04x\t%04x\t%04x\t%d\t%u\t%d\t%04x\t%d\t%u\t%u",
					prefix, 0,
					flags, 0, 0, 0,
					mask, 0, 0, 0);
	}
	memset(buffer+len, ' ', 127-len);
	buffer[127] = '\n';
}

static int dn_fib_table_get_info(struct dn_fib_table *tb, char *buffer, int first, int count)
{
	struct dn_hash *table = (struct dn_hash *)tb->data;
	struct dn_zone *dz;
	int pos = 0;
	int n = 0;

	read_lock(&dn_fib_tables_lock);
	for(dz = table->dh_zone_list; dz; dz = dz->dz_next) {
		int i;
		struct dn_fib_node *f;
		int maxslot = dz->dz_divisor;
		struct dn_fib_node **fp = dz->dz_hash;

		if (dz->dz_nent == 0)
			continue;

		if (pos + dz->dz_nent < first) {
			pos += dz->dz_nent;
			continue;
		}

		for(i = 0; i < maxslot; i++, fp++) {
			for(f = *fp; f ; f = f->fn_next) {
				if (++pos <= first)
					continue;
				dn_fib_node_get_info(f->fn_type,
						f->fn_state & DN_S_ZOMBIE,
						DN_FIB_INFO(f),
						dz_prefix(f->fn_key, dz),
						DZ_MASK(dz), buffer);
				buffer += 128;
				if (++n >= count)
					goto out;
			}
		}
	}
out:
	read_unlock(&dn_fib_tables_lock);
	return n;
}
#endif /* CONFIG_PROC_FS */

struct dn_fib_table *dn_fib_get_table(int n, int create)
{
        struct dn_fib_table *t;

        if (n < DN_MIN_TABLE)
                return NULL;

        if (n > DN_NUM_TABLES)
                return NULL;

        if (dn_fib_tables[n]) 
                return dn_fib_tables[n];

        if (!create)
                return NULL;

        if (in_interrupt() && net_ratelimit()) {
                printk(KERN_DEBUG "DECnet: BUG! Attempt to create routing table 
from interrupt\n"); 
                return NULL;
        }
        if ((t = kmalloc(sizeof(struct dn_fib_table), GFP_KERNEL)) == NULL)
                return NULL;

        memset(t, 0, sizeof(struct dn_fib_table));

        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;
#ifdef CONFIG_PROC_FS
	t->get_info = dn_fib_table_get_info;
#endif
#ifdef CONFIG_RTNETLINK
        t->dump = dn_fib_table_dump;
#endif
        dn_fib_tables[n] = t;

        return t;
}

static void dn_fib_del_tree(int n)
{
        struct dn_fib_table *t;

        write_lock(&dn_fib_tables_lock);
        t = dn_fib_tables[n];
        dn_fib_tables[n] = NULL;
        write_unlock(&dn_fib_tables_lock);

        if (t) {
                kfree(t);
        }
}

struct dn_fib_table *dn_fib_empty_table(void)
{
        int id;

        for(id = DN_MIN_TABLE; id <= DN_NUM_TABLES; id++)
                if (dn_fib_tables[id] == NULL)
                        return dn_fib_get_table(id, 1);
        return NULL;
}

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, NULL);
}

void __exit dn_fib_table_cleanup(void)
{
	int i;

	for (i = 0; i < DN_NUM_TABLES + 1; ++i)
		dn_fib_del_tree(i);

	return;
}