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Commit 4a287eba authored by Matti Vaittinen's avatar Matti Vaittinen Committed by David S. Miller
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IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag 



The support for NLM_F_* flags at IPv6 routing requests.

If NLM_F_CREATE flag is not defined for RTM_NEWROUTE request,
warning is printed, but no error is returned. Instead new route is
added. Later NLM_F_CREATE may be required for
new route creation.

Exception is when NLM_F_REPLACE flag is given without NLM_F_CREATE, and
no matching route is found. In this case it should be safe to assume
that the request issuer is familiar with NLM_F_* flags, and does really
not want route to be created.

Specifying NLM_F_REPLACE flag will now make the kernel to search for
matching route, and replace it with new one. If no route is found and
NLM_F_CREATE is specified as well, then new route is created.

Also, specifying NLM_F_EXCL will yield returning of error if matching
route is found.

Patch created against linux-3.2-rc1

Signed-off-by: default avatarMatti Vaittinen <Mazziesaccount@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d71314b4

net/ipv6/ip6_fib.c

+94 −15
Original line number Original line Diff line number Diff line
@@ -425,7 +425,8 @@ static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) 




static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,

static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,

				     int addrlen, int plen,

				     int addrlen, int plen,

				     int offset)

				     int offset, int allow_create,

				     int replace_required)

{

{

	struct fib6_node *fn, *in, *ln;

	struct fib6_node *fn, *in, *ln;

	struct fib6_node *pn = NULL;

	struct fib6_node *pn = NULL;
@@ -447,8 +448,12 @@ static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, 
		 *	Prefix match

		 *	Prefix match

		 */

		 */

		if (plen < fn->fn_bit ||

		if (plen < fn->fn_bit ||

		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))

		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {

			if (!allow_create)

				printk(KERN_WARNING

				    "IPv6: NLM_F_CREATE should be set when creating new route\n");

			goto insert_above;

			goto insert_above;

		}





		/*

		/*

		 *	Exact match ?

		 *	Exact match ?
@@ -477,10 +482,26 @@ static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, 
		fn = dir ? fn->right: fn->left;

		fn = dir ? fn->right: fn->left;

	} while (fn);

	} while (fn);





	if (replace_required && !allow_create) {

		/* We should not create new node because

		 * NLM_F_REPLACE was specified without NLM_F_CREATE

		 * I assume it is safe to require NLM_F_CREATE when

		 * REPLACE flag is used! Later we may want to remove the

		 * check for replace_required, because according

		 * to netlink specification, NLM_F_CREATE

		 * MUST be specified if new route is created.

		 * That would keep IPv6 consistent with IPv4

		 */

		printk(KERN_WARNING

		    "IPv6: NLM_F_CREATE should be set when creating new route - ignoring request\n");

		return ERR_PTR(-ENOENT);

	}

	/*

	/*

	 *	We walked to the bottom of tree.

	 *	We walked to the bottom of tree.

	 *	Create new leaf node without children.

	 *	Create new leaf node without children.

	 */

	 */

	if (!allow_create)

		printk(KERN_WARNING "IPv6: NLM_F_CREATE should be set when creating new route\n");





	ln = node_alloc();

	ln = node_alloc();
@@ -614,6 +635,12 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 
{

{

	struct rt6_info *iter = NULL;

	struct rt6_info *iter = NULL;

	struct rt6_info **ins;

	struct rt6_info **ins;

	int replace = (NULL != info &&

	    NULL != info->nlh &&

	    (info->nlh->nlmsg_flags&NLM_F_REPLACE));

	int add = ((NULL == info || NULL == info->nlh) ||

	    (info->nlh->nlmsg_flags&NLM_F_CREATE));

	int found = 0;





	ins = &fn->leaf;

	ins = &fn->leaf;
@@ -626,6 +653,13 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 
			/*

			/*

			 *	Same priority level

			 *	Same priority level

			 */

			 */

			if (NULL != info->nlh &&

			    (info->nlh->nlmsg_flags&NLM_F_EXCL))

				return -EEXIST;

			if (replace) {

				found++;

				break;

			}





			if (iter->rt6i_dev == rt->rt6i_dev &&

			if (iter->rt6i_dev == rt->rt6i_dev &&

			    iter->rt6i_idev == rt->rt6i_idev &&

			    iter->rt6i_idev == rt->rt6i_idev &&
@@ -655,7 +689,11 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 
	/*

	/*

	 *	insert node

	 *	insert node

	 */

	 */

	if (!replace) {

		if (!add)

			printk(KERN_WARNING "IPv6: NLM_F_CREATE should be set when creating new route\n");





add:

		rt->dst.rt6_next = iter;

		rt->dst.rt6_next = iter;

		*ins = rt;

		*ins = rt;

		rt->rt6i_node = fn;

		rt->rt6i_node = fn;
@@ -668,6 +706,25 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 
			fn->fn_flags |= RTN_RTINFO;

			fn->fn_flags |= RTN_RTINFO;

		}

		}





	} else {

		if (!found) {

			if (add)

				goto add;

			printk(KERN_WARNING "IPv6: NLM_F_REPLACE set, but no existing node found!\n");

			return -ENOENT;

		}

		*ins = rt;

		rt->rt6i_node = fn;

		rt->dst.rt6_next = iter->dst.rt6_next;

		atomic_inc(&rt->rt6i_ref);

		inet6_rt_notify(RTM_NEWROUTE, rt, info);

		rt6_release(iter);

		if ((fn->fn_flags & RTN_RTINFO) == 0) {

			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;

			fn->fn_flags |= RTN_RTINFO;

		}

	}



	return 0;

	return 0;

}

}
@@ -696,9 +753,25 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) 
{

{

	struct fib6_node *fn, *pn = NULL;

	struct fib6_node *fn, *pn = NULL;

	int err = -ENOMEM;

	int err = -ENOMEM;

	int allow_create = 1;

	int replace_required = 0;

	if (NULL != info && NULL != info->nlh) {

		if (!(info->nlh->nlmsg_flags&NLM_F_CREATE))

			allow_create = 0;

		if ((info->nlh->nlmsg_flags&NLM_F_REPLACE))

			replace_required = 1;

	}

	if (!allow_create && !replace_required)

		printk(KERN_WARNING "IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");





	fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),

	fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),

			rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));

		    rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),

		    allow_create, replace_required);



	if (IS_ERR(fn)) {

		err = PTR_ERR(fn);

		fn = NULL;

	}





	if (fn == NULL)

	if (fn == NULL)

		goto out;

		goto out;
@@ -736,7 +809,8 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) 




			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,

			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,

					sizeof(struct in6_addr), rt->rt6i_src.plen,

					sizeof(struct in6_addr), rt->rt6i_src.plen,

					offsetof(struct rt6_info, rt6i_src));

					offsetof(struct rt6_info, rt6i_src),

					allow_create, replace_required);





			if (sn == NULL) {

			if (sn == NULL) {

				/* If it is failed, discard just allocated

				/* If it is failed, discard just allocated
@@ -753,8 +827,13 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) 
		} else {

		} else {

			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,

			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,

					sizeof(struct in6_addr), rt->rt6i_src.plen,

					sizeof(struct in6_addr), rt->rt6i_src.plen,

					offsetof(struct rt6_info, rt6i_src));

					offsetof(struct rt6_info, rt6i_src),

					allow_create, replace_required);





			if (IS_ERR(sn)) {

				err = PTR_ERR(sn);

				sn = NULL;

			}

			if (sn == NULL)

			if (sn == NULL)

				goto st_failure;

				goto st_failure;

		}

		}