[PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[fgao]

From: Feng <fgao@ikuai8.com>

When something failed in nf_tables_table_enable, it would unregister
the chains. But the rollback codes are same as nf_tables_table_disable
almostly, except there is one counter check.
Now create one wrapper function to eliminate the duplicated codes.

Signed-off-by: Feng <fgao@ikuai8.com>
---
 v2: Use cnt "0" as unlimited rules counter, per Pablo;
 v1: Initial version;

 net/netfilter/nf_tables_api.c | 47 ++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a019a87..c87f8d0 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -576,6 +576,27 @@ static int nf_tables_gettable(struct net *net, struct sock *nlsk,
 	return err;
 }
 
+static void _nf_tables_table_disable(struct net *net,
+				     const struct nft_af_info *afi,
+				     struct nft_table *table,
+				     u32 cnt)
+{
+	struct nft_chain *chain;
+
+	list_for_each_entry(chain, &table->chains, list) {
+		if (!nft_is_active_next(net, chain))
+			continue;
+		if (!(chain->flags & NFT_BASE_CHAIN))
+			continue;
+
+		if (cnt && --cnt == 0)
+			break;
+
+		nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
+					afi->nops);
+	}
+}
+
 static int nf_tables_table_enable(struct net *net,
 				  const struct nft_af_info *afi,
 				  struct nft_table *table)
@@ -598,18 +619,8 @@ static int nf_tables_table_enable(struct net *net,
 	}
 	return 0;
 err:
-	list_for_each_entry(chain, &table->chains, list) {
-		if (!nft_is_active_next(net, chain))
-			continue;
-		if (!(chain->flags & NFT_BASE_CHAIN))
-			continue;
-
-		if (i-- <= 0)
-			break;
-
-		nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
-					afi->nops);
-	}
+	if (i)
+		_nf_tables_table_disable(net, afi, table, i);
 	return err;
 }
 
@@ -617,17 +628,7 @@ static void nf_tables_table_disable(struct net *net,
 				    const struct nft_af_info *afi,
 				    struct nft_table *table)
 {
-	struct nft_chain *chain;
-
-	list_for_each_entry(chain, &table->chains, list) {
-		if (!nft_is_active_next(net, chain))
-			continue;
-		if (!(chain->flags & NFT_BASE_CHAIN))
-			continue;
-
-		nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
-					afi->nops);
-	}
+	_nf_tables_table_disable(net, afi, table, 0);
 }
 
 static int nf_tables_updtable(struct nft_ctx *ctx)
-- 
1.9.1

Re: [PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[Feng Gao]

On Thu, Jan 19, 2017 at 7:18 PM,  <fgao@ikuai8.com> wrote:
> From: Feng <fgao@ikuai8.com>
>
> When something failed in nf_tables_table_enable, it would unregister
> the chains. But the rollback codes are same as nf_tables_table_disable
> almostly, except there is one counter check.
> Now create one wrapper function to eliminate the duplicated codes.
>
> Signed-off-by: Feng <fgao@ikuai8.com>
> ---
>  v2: Use cnt "0" as unlimited rules counter, per Pablo;
>  v1: Initial version;
>
>  net/netfilter/nf_tables_api.c | 47 ++++++++++++++++++++++---------------------
>  1 file changed, 24 insertions(+), 23 deletions(-)
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index a019a87..c87f8d0 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -576,6 +576,27 @@ static int nf_tables_gettable(struct net *net, struct sock *nlsk,
>         return err;
>  }
>
> +static void _nf_tables_table_disable(struct net *net,
> +                                    const struct nft_af_info *afi,
> +                                    struct nft_table *table,
> +                                    u32 cnt)
> +{
> +       struct nft_chain *chain;
> +
> +       list_for_each_entry(chain, &table->chains, list) {
> +               if (!nft_is_active_next(net, chain))
> +                       continue;
> +               if (!(chain->flags & NFT_BASE_CHAIN))
> +                       continue;
> +
> +               if (cnt && --cnt == 0)
> +                       break;
> +
> +               nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
> +                                       afi->nops);
> +       }
> +}
> +
>  static int nf_tables_table_enable(struct net *net,
>                                   const struct nft_af_info *afi,
>                                   struct nft_table *table)
> @@ -598,18 +619,8 @@ static int nf_tables_table_enable(struct net *net,
>         }
>         return 0;
>  err:
> -       list_for_each_entry(chain, &table->chains, list) {
> -               if (!nft_is_active_next(net, chain))
> -                       continue;
> -               if (!(chain->flags & NFT_BASE_CHAIN))
> -                       continue;
> -
> -               if (i-- <= 0)
> -                       break;
> -
> -               nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
> -                                       afi->nops);
> -       }
> +       if (i)
> +               _nf_tables_table_disable(net, afi, table, i);
>         return err;
>  }
>
> @@ -617,17 +628,7 @@ static void nf_tables_table_disable(struct net *net,
>                                     const struct nft_af_info *afi,
>                                     struct nft_table *table)
>  {
> -       struct nft_chain *chain;
> -
> -       list_for_each_entry(chain, &table->chains, list) {
> -               if (!nft_is_active_next(net, chain))
> -                       continue;
> -               if (!(chain->flags & NFT_BASE_CHAIN))
> -                       continue;
> -
> -               nf_unregister_net_hooks(net, nft_base_chain(chain)->ops,
> -                                       afi->nops);
> -       }
> +       _nf_tables_table_disable(net, afi, table, 0);
>  }
>
>  static int nf_tables_updtable(struct nft_ctx *ctx)
> --
> 1.9.1
>
>

Hi Pablo,

Please ignore this patch.
In v2 patch, I copied your recommend codes "if (cnt && --cnt == 0)".
Today I think it is not right to use "--cnt", it should use "cnt--".
Because when the cnt is 1, the "--cnt" would break directly.
So I send the v3 patch.

Regards
Feng

Re: [PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[Liping Zhang]

2017-01-20 15:42 GMT+08:00 Feng Gao <gfree.wind@gmail.com>:
[...]
> In v2 patch, I copied your recommend codes "if (cnt && --cnt == 0)".
> Today I think it is not right to use "--cnt", it should use "cnt--".
> Because when the cnt is 1, the "--cnt" would break directly.
> So I send the v3 patch.

But this "if (cnt && cnt-- == 0) break;" check condition seems still incorrect,
when the cnt is 1, next round cnt will become 0, so we will fail to break the
loop ...

Re: [PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[Feng Gao]

Hi Liping,

On Fri, Jan 20, 2017 at 6:57 PM, Liping Zhang <zlpnobody@gmail.com> wrote:
> 2017-01-20 15:42 GMT+08:00 Feng Gao <gfree.wind@gmail.com>:
> [...]
>> In v2 patch, I copied your recommend codes "if (cnt && --cnt == 0)".
>> Today I think it is not right to use "--cnt", it should use "cnt--".
>> Because when the cnt is 1, the "--cnt" would break directly.
>> So I send the v3 patch.
>
> But this "if (cnt && cnt-- == 0) break;" check condition seems still incorrect,
> when the cnt is 1, next round cnt will become 0, so we will fail to break the
> loop ...

Thanks your catch.
So we should keep the "(cnt && --cnt == 0)", with
_nf_tables_table_disable(net, afi, table, i+1) in the error handler of
nf_tables_table_enable.

Do you think if "i+1" is a little werid?

Regards
Feng

Re: [PATCH nf-next v2 1/1] netfilter: nf_tables: Eliminate duplicated codes in nf_tables_table_enable

[Feng Gao]

On Fri, Jan 20, 2017 at 8:30 PM, Feng Gao <gfree.wind@gmail.com> wrote:
> Hi Liping,
>
> On Fri, Jan 20, 2017 at 6:57 PM, Liping Zhang <zlpnobody@gmail.com> wrote:
>> 2017-01-20 15:42 GMT+08:00 Feng Gao <gfree.wind@gmail.com>:
>> [...]
>>> In v2 patch, I copied your recommend codes "if (cnt && --cnt == 0)".
>>> Today I think it is not right to use "--cnt", it should use "cnt--".
>>> Because when the cnt is 1, the "--cnt" would break directly.
>>> So I send the v3 patch.
>>
>> But this "if (cnt && cnt-- == 0) break;" check condition seems still incorrect,
>> when the cnt is 1, next round cnt will become 0, so we will fail to break the
>> loop ...
>
> Thanks your catch.
> So we should keep the "(cnt && --cnt == 0)", with
> _nf_tables_table_disable(net, afi, table, i+1) in the error handler of
> nf_tables_table_enable.
>
> Do you think if "i+1" is a little werid?
>
> Regards
> Feng

Because the cnt has two usages, it is used as one flag and one counter.
So it is hard to meet these two requirements.

Then I bring one new counter "i", when cnt is positive and i equals
cnt, it could break.
The codes like following:
if (cnt && i++ == cnt) and the i is initialized as 0.

The v4 patch is sent already.

Regards
Feng