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authorThomas Graf <tgraf@infradead.org>2010-11-22 01:31:54 +0000
committerDavid S. Miller <davem@davemloft.net>2010-11-27 22:56:08 -0800
commitcf7afbfeb8ceb0187348d0a1a0db61305e25f05f (patch)
tree8b1c07c8ae6a5b3f6f050d3286b53b3d7d72c858 /net/ipv4/devinet.c
parent89bf67f1f080c947c92f8773482d9e57767ca292 (diff)
rtnl: make link af-specific updates atomic
As David pointed out correctly, updates to af-specific attributes are currently not atomic. If multiple changes are requested and one of them fails, previous updates may have been applied already leaving the link behind in a undefined state. This patch splits the function parse_link_af() into two functions validate_link_af() and set_link_at(). validate_link_af() is placed to validate_linkmsg() check for errors as early as possible before any changes to the link have been made. set_link_af() is called to commit the changes later. This method is not fail proof, while it is currently sufficient to make set_link_af() inerrable and thus 100% atomic, the validation function method will not be able to detect all error scenarios in the future, there will likely always be errors depending on states which are f.e. not protected by rtnl_mutex and thus may change between validation and setting. Also, instead of silently ignoring unknown address families and config blocks for address families which did not register a set function the errors EAFNOSUPPORT respectively EOPNOSUPPORT are returned to avoid comitting 4 out of 5 update requests without notifying the user. Signed-off-by: Thomas Graf <tgraf@infradead.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/devinet.c')
-rw-r--r--net/ipv4/devinet.c26
1 files changed, 21 insertions, 5 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 71afc26c2df..d9f71bae45c 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1289,14 +1289,14 @@ static const struct nla_policy inet_af_policy[IFLA_INET_MAX+1] = {
[IFLA_INET_CONF] = { .type = NLA_NESTED },
};
-static int inet_parse_link_af(struct net_device *dev, const struct nlattr *nla)
+static int inet_validate_link_af(const struct net_device *dev,
+ const struct nlattr *nla)
{
- struct in_device *in_dev = __in_dev_get_rcu(dev);
struct nlattr *a, *tb[IFLA_INET_MAX+1];
int err, rem;
- if (!in_dev)
- return -EOPNOTSUPP;
+ if (dev && !__in_dev_get_rcu(dev))
+ return -EAFNOSUPPORT;
err = nla_parse_nested(tb, IFLA_INET_MAX, nla, inet_af_policy);
if (err < 0)
@@ -1314,6 +1314,21 @@ static int inet_parse_link_af(struct net_device *dev, const struct nlattr *nla)
}
}
+ return 0;
+}
+
+static int inet_set_link_af(struct net_device *dev, const struct nlattr *nla)
+{
+ struct in_device *in_dev = __in_dev_get_rcu(dev);
+ struct nlattr *a, *tb[IFLA_INET_MAX+1];
+ int rem;
+
+ if (!in_dev)
+ return -EAFNOSUPPORT;
+
+ if (nla_parse_nested(tb, IFLA_INET_MAX, nla, NULL) < 0)
+ BUG();
+
if (tb[IFLA_INET_CONF]) {
nla_for_each_nested(a, tb[IFLA_INET_CONF], rem)
ipv4_devconf_set(in_dev, nla_type(a), nla_get_u32(a));
@@ -1689,7 +1704,8 @@ static struct rtnl_af_ops inet_af_ops = {
.family = AF_INET,
.fill_link_af = inet_fill_link_af,
.get_link_af_size = inet_get_link_af_size,
- .parse_link_af = inet_parse_link_af,
+ .validate_link_af = inet_validate_link_af,
+ .set_link_af = inet_set_link_af,
};
void __init devinet_init(void)