Hi Phil,
On 3/13/19 10:44 AM, Phil Sutter wrote:
> Hi Fernando,
>
> On Mon, Mar 11, 2019 at 04:14:12PM +0100, Fernando Fernandez Mancera wrote:
>> Add support for version fingerprint in "osf" expression. Example:
>>
>> table ip foo {
>> chain bar {
>> type filter hook input priority filter; policy accept;
>> osf ttl skip name "Linux"
>> osf ttl skip name version "Linux:4.20"
>> }
>> }
>
> The syntax seems overly complicated to me, although I'm not really
> familiar with OSF so may lack background knowledge. Any reason why you
> didn't go with 'osf ttl skip name "Linux" version "4.20"' instead?
>
You are right, 'osf ttl skip name "Linux" version "4.20"' was my first
thought but in compilation time the parser applies shift-reduce to the
expression.. I decided 'osf ttl skip name version "Linux:4.20"' to avoid
a complex workaround in the parser.
The fingerprints database syntax is "genre:version:subtype:details" so
the nft 'osf' expression syntax is like the original one.
> Also with regards to your patch to json_parser, I guess you should
> introduce an enum for flag values, something like:
>
> | enum osf_flags {
> | OSF_FLAG_INVALID = 0x0,
> | OSF_FLAG_VERSION = 0x1
> | };
> |
> | const char *osf_flag_names[] = {
> | [OSF_VERSION] = "version"
> | };
>
> What do you think?
>
This patch already introduces an enum for flags values, you can find it
below. Do you think we need another one? Sorry if I am misunderstanding
you. Thanks!
diff --git a/include/linux/netfilter/nf_tables.h
b/include/linux/netfilter/nf_tables.h
index 37036be..09a7b9e 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -944,15 +944,21 @@ enum nft_socket_keys {
*
* @NFTA_OSF_DREG: destination register (NLA_U32: nft_registers)
* @NFTA_OSF_TTL: Value of the TTL osf option (NLA_U8)
+ * @NFTA_OSF_FLAGS: flags (NLA_U32)
*/
enum nft_osf_attributes {
NFTA_OSF_UNSPEC,
NFTA_OSF_DREG,
NFTA_OSF_TTL,
+ NFTA_OSF_FLAGS,
__NFTA_OSF_MAX
};
#define NFT_OSF_MAX (__NFTA_OSF_MAX - 1)
+enum nft_osf_flags {
+ NFT_OSF_F_VERSION = 1 << 0, /* check fingerprint version */
+};
+
/**
* enum nft_ct_keys - nf_tables ct expression keys
*
> Cheers, Phil
>
