Re: [libnftables PATCH v3] src: add _unset functions

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Fri, Jun 07, 2013 at 12:52:17PM +0200, Arturo Borrero wrote:
> These functions unset the flag for the given attribute in each object and free data in some cases.

Applied with minor changes, thanks Arturo.

See below.

> Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
> ---
> v2: improved unset operation and freed data pointer set to NULL
> v3: set to null c->table
> 
>  include/libnftables/chain.h |    1 +
>  include/libnftables/rule.h  |    1 +
>  include/libnftables/set.h   |    2 ++
>  include/libnftables/table.h |    1 +
>  src/chain.c                 |   26 ++++++++++++++++++++++++++
>  src/libnftables.map         |    5 +++++
>  src/rule.c                  |   23 +++++++++++++++++++++++
>  src/set.c                   |   23 +++++++++++++++++++++++
>  src/set_elem.c              |   13 +++++++++++++
>  src/table.c                 |   15 ++++++++++++++-
>  10 files changed, 109 insertions(+), 1 deletion(-)
> 
> diff --git a/include/libnftables/chain.h b/include/libnftables/chain.h
> index b12474f..f06f743 100644
> --- a/include/libnftables/chain.h
> +++ b/include/libnftables/chain.h
> @@ -26,6 +26,7 @@ enum {
>  	NFT_CHAIN_ATTR_TYPE,
>  };
>  
> +void nft_chain_attr_unset(struct nft_chain *c, uint16_t attr);
>  void nft_chain_attr_set(struct nft_chain *t, uint16_t attr, const void *data);
>  void nft_chain_attr_set_u32(struct nft_chain *t, uint16_t attr, uint32_t data);
>  void nft_chain_attr_set_s32(struct nft_chain *t, uint16_t attr, int32_t data);
> diff --git a/include/libnftables/rule.h b/include/libnftables/rule.h
> index 9c4ab0d..9989f19 100644
> --- a/include/libnftables/rule.h
> +++ b/include/libnftables/rule.h
> @@ -23,6 +23,7 @@ enum {
>  	NFT_RULE_ATTR_COMPAT_FLAGS,
>  };
>  
> +void nft_rule_attr_unset(struct nft_rule *r, uint16_t attr);
>  void nft_rule_attr_set(struct nft_rule *r, uint16_t attr, const void *data);
>  void nft_rule_attr_set_u32(struct nft_rule *r, uint16_t attr, uint32_t val);
>  void nft_rule_attr_set_u64(struct nft_rule *r, uint16_t attr, uint64_t val);
> diff --git a/include/libnftables/set.h b/include/libnftables/set.h
> index 53c2947..211c065 100644
> --- a/include/libnftables/set.h
> +++ b/include/libnftables/set.h
> @@ -16,6 +16,7 @@ struct nft_set;
>  struct nft_set *nft_set_alloc(void);
>  void nft_set_free(struct nft_set *s);
>  
> +void nft_set_attr_unset(struct nft_set *s, uint16_t attr);
>  void nft_set_attr_set(struct nft_set *s, uint16_t attr, const void *data);
>  void nft_set_attr_set_u32(struct nft_set *s, uint16_t attr, uint32_t val);
>  void nft_set_attr_set_str(struct nft_set *s, uint16_t attr, const char *str);
> @@ -61,6 +62,7 @@ void nft_set_elem_free(struct nft_set_elem *s);
>  
>  void nft_set_elem_add(struct nft_set *s, struct nft_set_elem *elem);
>  
> +void nft_set_elem_attr_unset(struct nft_set_elem *s, uint16_t attr);
>  void nft_set_elem_attr_set(struct nft_set_elem *s, uint16_t attr, const void *data, size_t data_len);
>  void nft_set_elem_attr_set_u32(struct nft_set_elem *s, uint16_t attr, uint32_t val);
>  void nft_set_elem_attr_set_str(struct nft_set_elem *s, uint16_t attr, const char *str);
> diff --git a/include/libnftables/table.h b/include/libnftables/table.h
> index 658230c..09cd204 100644
> --- a/include/libnftables/table.h
> +++ b/include/libnftables/table.h
> @@ -18,6 +18,7 @@ enum {
>  	NFT_TABLE_ATTR_FLAGS,
>  };
>  
> +void nft_table_attr_unset(struct nft_table *t, uint16_t attr);
>  void nft_table_attr_set(struct nft_table *t, uint16_t attr, const void *data);
>  const void *nft_table_attr_get(struct nft_table *t, uint16_t attr);
>  
> diff --git a/src/chain.c b/src/chain.c
> index 093e3ea..2a1a7ce 100644
> --- a/src/chain.c
> +++ b/src/chain.c
> @@ -59,6 +59,32 @@ void nft_chain_free(struct nft_chain *c)
>  }
>  EXPORT_SYMBOL(nft_chain_free);
>  
> +void nft_chain_attr_unset(struct nft_chain *c, uint16_t attr)
> +{
> +	switch (attr) {
> +	case NFT_CHAIN_ATTR_TABLE:
> +		if (c->flags & (1 << NFT_CHAIN_ATTR_TABLE))
> +			if (c->table) {
> +				free(c->table);
> +				c->table = NULL;
> +			}
> +		break;
> +	case NFT_CHAIN_ATTR_USE:
> +		/* cannot be unset?, ignore it */
> +		return;
> +	case NFT_CHAIN_ATTR_TYPE:
> +		if (c->flags & (1 << NFT_CHAIN_ATTR_TYPE))
> +			if (c->type) {
> +				free(c->type);
> +				c->type = NULL;
> +			}
> +		break;

        default:
                return;

Added this just to skip for unknown attributes. It should not harm
though the current code, but just to ensure we don't spend cycles on
no operations.

> +	}
> +
> +	c->flags &= ~(1 << attr);
> +}
> +EXPORT_SYMBOL(nft_chain_attr_unset);
> +
[...]
> +void nft_table_attr_unset(struct nft_table *t, uint16_t attr)
> +{
> +	if (attr == NFT_TABLE_ATTR_NAME)
> +		if (t->flags & (1 << NFT_TABLE_ATTR_NAME))
> +			if (t->name) {
> +				free(t->name);
> +				t->name = NULL;
> +			}

Converted this to a switch. We only have one single choice now, but
there are other attributes like flags and family that we may want to
unset in the future.

Regards.