[PATCH v2] extensions: libipt_ttl: Add translation to nft

[PATCH v2] extensions: libipt_ttl: Add translation to nft

[Shivani Bhardwaj]

Add translation for module ttl to nftables.

Examples:

$ sudo iptables-translate -A INPUT -m ttl --ttl-eq 3 -j ACCEPT
nft add rule ip filter INPUT ip ttl 3 counter accept

$ sudo iptables-translate -A INPUT -m ttl --ttl-gt 5 -j ACCEPT
nft add rule ip filter INPUT ip ttl \> 5 counter accept

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
---
Changes in v2:
	Remove the changes done in nft-ipv4

 extensions/libipt_ttl.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
index 5fe08cc..5d897a7 100644
--- a/extensions/libipt_ttl.c
+++ b/extensions/libipt_ttl.c
@@ -100,6 +100,35 @@ static void ttl_save(const void *ip, const struct xt_entry_match *match)
 	printf(" %u", info->ttl);
 }
 
+static int ttl_xlate(const struct xt_entry_match *match,
+		     struct xt_buf *buf, int numeric)
+{
+	const struct ipt_ttl_info *info =
+			(struct ipt_ttl_info *) match->data;
+
+		switch (info->mode) {
+		case IPT_TTL_EQ:
+			xt_buf_add(buf, "ip ttl");
+			break;
+		case IPT_TTL_NE:
+			xt_buf_add(buf, "ip ttl !=");
+			break;
+		case IPT_TTL_LT:
+			xt_buf_add(buf, "ip ttl \\<");
+			break;
+		case IPT_TTL_GT:
+			xt_buf_add(buf, "ip ttl \\>");
+			break;
+		default:
+			/* error */
+			break;
+	}
+
+	xt_buf_add(buf, " %u ", info->ttl);
+
+	return 1;
+}
+
 #define s struct ipt_ttl_info
 static const struct xt_option_entry ttl_opts[] = {
 	{.name = "ttl-lt", .id = O_TTL_LT, .excl = F_ANY, .type = XTTYPE_UINT8,
@@ -126,6 +155,7 @@ static struct xtables_match ttl_mt_reg = {
 	.x6_parse	= ttl_parse,
 	.x6_fcheck	= ttl_check,
 	.x6_options	= ttl_opts,
+	.xlate		= ttl_xlate,
 };
 
 
-- 
1.9.1

Re: [PATCH v2] extensions: libipt_ttl: Add translation to nft

[Pablo Neira Ayuso]

On Mon, Jan 04, 2016 at 11:30:02PM +0530, Shivani Bhardwaj wrote:
> Add translation for module ttl to nftables.
> 
> Examples:
> 
> $ sudo iptables-translate -A INPUT -m ttl --ttl-eq 3 -j ACCEPT
> nft add rule ip filter INPUT ip ttl 3 counter accept
> 
> $ sudo iptables-translate -A INPUT -m ttl --ttl-gt 5 -j ACCEPT
> nft add rule ip filter INPUT ip ttl \> 5 counter accept

Applied with minor glitch.

> Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
> ---
> Changes in v2:
> 	Remove the changes done in nft-ipv4
> 
>  extensions/libipt_ttl.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
> index 5fe08cc..5d897a7 100644
> --- a/extensions/libipt_ttl.c
> +++ b/extensions/libipt_ttl.c
> @@ -100,6 +100,35 @@ static void ttl_save(const void *ip, const struct xt_entry_match *match)
>  	printf(" %u", info->ttl);
>  }
>  
> +static int ttl_xlate(const struct xt_entry_match *match,
> +		     struct xt_buf *buf, int numeric)
> +{
> +	const struct ipt_ttl_info *info =
> +			(struct ipt_ttl_info *) match->data;
> +
> +		switch (info->mode) {
> +		case IPT_TTL_EQ:
> +			xt_buf_add(buf, "ip ttl");
> +			break;
> +		case IPT_TTL_NE:
> +			xt_buf_add(buf, "ip ttl !=");
> +			break;
> +		case IPT_TTL_LT:
> +			xt_buf_add(buf, "ip ttl \\<");

I prefer you use 'lt' instead of \\<.

> +			break;
> +		case IPT_TTL_GT:
> +			xt_buf_add(buf, "ip ttl \\>");

Same thing here: use 'gt'.

No need to resend, I have fixed this here.

Thanks.