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authorJohannes Berg <johannes.berg@intel.com>2018-09-26 12:15:33 +0300
committerDavid S. Miller <davem@davemloft.net>2018-09-28 20:24:39 +0300
commit9a659a35ba177cec30676e170fb6ed98157bcb0d (patch)
tree0a551784a6b946553793306790e75e1bb69d4f83 /include
parentc29f1845b2b22974411278bad3a2ac0b7815dfb4 (diff)
downloadlinux-9a659a35ba177cec30676e170fb6ed98157bcb0d.tar.xz
netlink: allow NLA_NESTED to specify nested policy to validate
Now that we have a validation_data pointer, and the len field in the policy is unused for NLA_NESTED, we can allow using them both to have nested validation. This can be nice in code, although we still have to use nla_parse_nested() or similar which would also take a policy; however, it also serves as documentation in the policy without requiring a look at the code. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/netlink.h13
1 files changed, 11 insertions, 2 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 0d698215d4d9..91907852da1c 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -200,8 +200,10 @@ enum {
* NLA_NUL_STRING Maximum length of string (excluding NUL)
* NLA_FLAG Unused
* NLA_BINARY Maximum length of attribute payload
- * NLA_NESTED Don't use `len' field -- length verification is
- * done by checking len of nested header (or empty)
+ * NLA_NESTED Length verification is done by checking len of
+ * nested header (or empty); len field is used if
+ * validation_data is also used, for the max attr
+ * number in the nested policy.
* NLA_U8, NLA_U16,
* NLA_U32, NLA_U64,
* NLA_S8, NLA_S16,
@@ -224,6 +226,10 @@ enum {
* NLA_REJECT This attribute is always rejected and validation data
* may point to a string to report as the error instead
* of the generic one in extended ACK.
+ * NLA_NESTED Points to a nested policy to validate, must also set
+ * `len' to the max attribute number.
+ * Note that nla_parse() will validate, but of course not
+ * parse, the nested sub-policies.
* All other Unused
*
* Example:
@@ -247,6 +253,9 @@ struct nla_policy {
#define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN)
#define NLA_POLICY_ETH_ADDR_COMPAT NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
+#define NLA_POLICY_NESTED(maxattr, policy) \
+ { .type = NLA_NESTED, .validation_data = policy, .len = maxattr }
+
/**
* struct nl_info - netlink source information
* @nlh: Netlink message header of original request