When adding rule with NLM_F_EXCL flag then check if the same rule exist.
If yes then exit with -EEXIST.
This is already implemented in iproute2:
if (cmd == RTM_NEWRULE) {
req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
req.r.rtm_type = RTN_UNICAST;
}
Tested ipv4 and ipv6 with net-next linux on qemu x86
expected behavior after patch:
localhost ~ # ip rule
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
RTNETLINK answers: File exists
localhost ~ # ip rule
0: from all lookup local
1005: from 10.46.177.97 lookup 104
32766: from all lookup main
32767: from all lookup default
There was already topic regarding this but I don't see any changes
merged and problem still occurs.
https://lkml.kernel.org/r/1135778809.5944.7.camel+%28%29+localhost+%21+localdomain
Signed-off-by: Mateusz Bajorski <mateusz.bajor...@nokia.com>
---
Changes in v2: section moved to new place where new rule is already built
Changes in v3: compare moved to helper, added fr_net compare
net/core/fib_rules.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 98298b1..fa0c3ff 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -269,6 +269,46 @@ errout:
return err;
}
+static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
+ struct nlattr **tb, struct fib_rule *rule)
+{
+ struct fib_rule *r;
+
+ list_for_each_entry(r, &ops->rules_list, list) {
+ if (r->action != rule->action)
+ continue;
+
+ if (r->table != rule->table)
+ continue;
+
+ if (r->pref != rule->pref)
+ continue;
+
+ if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
+ continue;
+
+ if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
+ continue;
+
+ if (r->mark != rule->mark)
+ continue;
+
+ if (r->mark_mask != rule->mark_mask)
+ continue;
+
+ if (r->tun_id != rule->tun_id)
+ continue;
+
+ if (r->fr_net != rule->fr_net)
+ continue;
+
+ if (!ops->compare(r, frh, tb))
+ continue;
+ return 1;
+ }
+ return 0;
+}
+
int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
@@ -386,6 +426,12 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr
*nlh)
if (rule->l3mdev && rule->table)
goto errout_free;
+ if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
+ rule_exists(ops, frh, tb, rule)) {
+ err = -EEXIST;
+ goto errout_free;
+ }
+
err = ops->configure(rule, skb, frh, tb);
if (err < 0)
goto errout_free;
--
2.6.4
