Hi Harsha,
On Sat, Dec 23, 2017 at 11:44:20AM -0800, Harsha Sharma wrote:
> This patch adds code to allocate 'handle' in tables, which allow us to
> uniquely identify a table.
>
> Signed-off-by: Harsha Sharma <harshasharmaiitr@xxxxxxxxx>
> ---
> include/net/netfilter/nf_tables.h | 2 ++
> include/uapi/linux/netfilter/nf_tables.h | 2 ++
> net/netfilter/nf_tables_api.c | 12 +++++++++++-
> 3 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
> index 01570a8f2982..bbc7bfcc1a57 100644
> --- a/include/net/netfilter/nf_tables.h
> +++ b/include/net/netfilter/nf_tables.h
> @@ -949,6 +949,7 @@ unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv);
> * @sets: sets in the table
> * @objects: stateful objects in the table
> * @hgenerator: handle generator state
> + * @handle: table handle
> * @use: number of chain references to this table
> * @flags: table flag (see enum nft_table_flags)
> * @genmask: generation mask
> @@ -960,6 +961,7 @@ struct nft_table {
> struct list_head sets;
> struct list_head objects;
> u64 hgenerator;
> + u64 handle:42;
> u32 use;
> u16 flags:14,
> genmask:2;
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index a3ee277b17a1..a6ab9a962eae 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -168,6 +168,8 @@ enum nft_table_attributes {
> NFTA_TABLE_NAME,
> NFTA_TABLE_FLAGS,
> NFTA_TABLE_USE,
> + NFTA_TABLE_HANDLE,
> + NFTA_TABLE_PAD,
> __NFTA_TABLE_MAX
> };
> #define NFTA_TABLE_MAX (__NFTA_TABLE_MAX - 1)
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index d8327b43e4dc..4a4e247e6028 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -22,6 +22,7 @@
> #include <net/net_namespace.h>
> #include <net/sock.h>
>
> +static u64 table_handle;
You need to place this handle number in struct nft_table.
> static LIST_HEAD(nf_tables_expressions);
> static LIST_HEAD(nf_tables_objects);
>
> @@ -430,6 +431,7 @@ static const struct nla_policy nft_table_policy[NFTA_TABLE_MAX + 1] = {
> [NFTA_TABLE_NAME] = { .type = NLA_STRING,
> .len = NFT_TABLE_MAXNAMELEN - 1 },
> [NFTA_TABLE_FLAGS] = { .type = NLA_U32 },
> + [NFTA_TABLE_HANDLE] = { .type = NLA_U64 },
^^^
missing tab indent here.
> };
>
> static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
> @@ -451,7 +453,9 @@ static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
>
> if (nla_put_string(skb, NFTA_TABLE_NAME, table->name) ||
> nla_put_be32(skb, NFTA_TABLE_FLAGS, htonl(table->flags)) ||
> - nla_put_be32(skb, NFTA_TABLE_USE, htonl(table->use)))
> + nla_put_be32(skb, NFTA_TABLE_USE, htonl(table->use)) ||
> + nla_put_be64(skb, NFTA_TABLE_HANDLE, cpu_to_be64(table->handle),
> + NFTA_TABLE_PAD))
> goto nla_put_failure;
>
> nlmsg_end(skb, nlh);
> @@ -734,6 +738,12 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
> INIT_LIST_HEAD(&table->sets);
> INIT_LIST_HEAD(&table->objects);
> table->flags = flags;
> + if (nla[NFTA_TABLE_HANDLE]) {
> + table->handle = be64_to_cpu(nla_get_be64(nla[NFTA_TABLE_HANDLE]));
We don't allow to restore the handle, please remove this line.
> + } else {
> + table_handle++;
> + table->handle = table_handle;
> + }
>
> nft_ctx_init(&ctx, net, skb, nlh, afi, table, NULL, nla);
> err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
We need to implement deletion via handle too in nf_tables_deltable(),
same thing for nf_table_gettable().
Thus, the unique handle becomes useful.
Thanks.
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