[PATCH v2] netfilter: nf_tables: allocate table handle

[Harsha Sharma <harshasharmaiitr@gmail.com>]

This patch adds code to allocate 'handle' in tables, which allow us to
uniquely identify a table.

Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
---
Changes in v2:
 -Don't restore table handle in nf_tables_newtable
 -Remove spaces before tabs

 include/net/netfilter/nf_tables.h        | 2 ++
 include/uapi/linux/netfilter/nf_tables.h | 2 ++
 net/netfilter/nf_tables_api.c            | 7 ++++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 01570a8f2982..488a8d8b41d2 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..dabdd2ed66c8 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;
 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 },
 };
 
 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 +738,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
 	INIT_LIST_HEAD(&table->sets);
 	INIT_LIST_HEAD(&table->objects);
 	table->flags = flags;
+	table->handle = ++table_handle;
 
 	nft_ctx_init(&ctx, net, skb, nlh, afi, table, NULL, nla);
 	err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
-- 
2.11.0