From a5f25889216411ad7492047fafe6de03b8408440 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Sun, 9 May 2010 20:17:54 +0200
Subject: relax mnl_attr_type_valid() checkings and change errno value
This patch relaxes strict attribute checkings in the example files.
I have also changed the errno value, now it's EOPNOTSUPP instead of
EINVAL.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
src/attr.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
(limited to 'src')
diff --git a/src/attr.c b/src/attr.c
index 37fa798..d220652 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -115,11 +115,16 @@ struct nlattr *mnl_attr_next(const struct nlattr *attr, int *len)
* This function allows to check if the attribute type is higher than the
* maximum supported type. If the attribute type is invalid, this function
* returns -1 and errno is explicitly set. On success, this function returns 1.
+ *
+ * Strict attribute checking in user-space is not a good idea since you may
+ * run an old application with a newer kernel that supports new attributes.
+ * This leads to backward compatibility breakages in user-space. Better check
+ * if you support an attribute, if not, skip it.
*/
int mnl_attr_type_valid(const struct nlattr *attr, uint16_t max)
{
if (mnl_attr_get_type(attr) > max) {
- errno = EINVAL;
+ errno = EOPNOTSUPP;
return -1;
}
return 1;
--
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