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Message-Id: <1320304579.2755.1.camel@lakki>
Date: Thu, 03 Nov 2011 09:16:19 +0200
From: Matti Vaittinen <matti.vaittinen@....com>
To: davem <davem@...emloft.net>, shemminger@...tta.com
Cc: netdev <netdev@...r.kernel.org>
Subject: [PATCH 2/2] IPv6 - support for NLM_F_* flags at IPv6 routing
requests
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.
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 is created against linux-3.1-rc4
Signed-off-by: Matti Vaittinen <Mazziesaccount@...il.com>
diff -uNr linux-3.1-rc4.orig/net/ipv6/ip6_fib.c linux-3.1-rc4.new/net/ipv6/ip6_fib.c
--- linux-3.1-rc4.orig/net/ipv6/ip6_fib.c 2011-11-01 14:01:55.000000000 +0200
+++ linux-3.1-rc4.new/net/ipv6/ip6_fib.c 2011-11-03 08:34:51.000000000 +0200
@@ -429,7 +429,8 @@
static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
int addrlen, int plen,
- int offset)
+ int offset, int allow_create,
+ int replace_required)
{
struct fib6_node *fn, *in, *ln;
struct fib6_node *pn = NULL;
@@ -451,8 +452,12 @@
* Prefix match
*/
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
+ "NLM_F_CREATE should be specified when creating new rt\n");
goto insert_above;
+ }
/*
* Exact match ?
@@ -481,10 +486,26 @@
fn = dir ? fn->right: fn->left;
} 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
+ "NLM_F_CREATE should be specified when creating new rt - ignoring request\n");
+ return ERR_PTR(-ENOENT);
+ }
/*
* We walked to the bottom of tree.
* Create new leaf node without children.
*/
+ if (!allow_create)
+ printk(KERN_WARNING "NLM_F_CREATE should be specified when creating new rt\n");
ln = node_alloc();
@@ -618,6 +639,12 @@
{
struct rt6_info *iter = NULL;
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;
@@ -630,6 +657,13 @@
/*
* 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 &&
iter->rt6i_idev == rt->rt6i_idev &&
@@ -659,17 +693,40 @@
/*
* insert node
*/
+ if (!replace) {
+ if (!add)
+ printk(KERN_WARNING "NLM_F_CREATE should be specified when creating new rt\n");
+
+add:
+ rt->dst.rt6_next = iter;
+ *ins = rt;
+ rt->rt6i_node = fn;
+ atomic_inc(&rt->rt6i_ref);
+ inet6_rt_notify(RTM_NEWROUTE, rt, info);
+ info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
+
+ if ((fn->fn_flags & RTN_RTINFO) == 0) {
+ info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
+ fn->fn_flags |= RTN_RTINFO;
+ }
- rt->dst.rt6_next = iter;
- *ins = rt;
- rt->rt6i_node = fn;
- atomic_inc(&rt->rt6i_ref);
- inet6_rt_notify(RTM_NEWROUTE, rt, info);
- info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
-
- if ((fn->fn_flags & RTN_RTINFO) == 0) {
- info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
- fn->fn_flags |= RTN_RTINFO;
+ } else {
+ if (!found) {
+ if (add)
+ goto add;
+ printk(KERN_WARNING "add rtinfo to node - NLM_F_REPLACE specified, but no existing node found! bailing out\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;
@@ -700,9 +757,25 @@
{
struct fib6_node *fn, *pn = NULL;
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 "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),
- 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)
goto out;
@@ -740,7 +813,8 @@
sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
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 it is failed, discard just allocated
@@ -757,8 +831,13 @@
} else {
sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
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)
goto st_failure;
}
--
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