[RFC] extensions: libxt_TOS: Add translation to nft

[RFC] extensions: libxt_TOS: Add translation to nft

[Gargi Sharma]

Add translation for TOS to nftables.

Examples:

$ iptables-translate -t mangle -A PREROUTING -p TCP --dport 22 -j TOS --set-tos 0x10
nft add rule ip mangle PREROUTING tcp dport 22 counter --set-tos 0x10/0xff

$ iptables-translate -A PREROUTING -t mangle -p tcp --sport ftp-data -j TOS --set-tos 0x02/0x10
nft add rule ip mangle PREROUTING tcp sport 20 counter --set-tos 0x02/0x10

Signed-off-by: Gargi Sharma <gs051095@gmail.com>
---
 extensions/libxt_TOS.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/extensions/libxt_TOS.c b/extensions/libxt_TOS.c
index cef5876..408918b 100644
--- a/extensions/libxt_TOS.c
+++ b/extensions/libxt_TOS.c
@@ -183,6 +183,26 @@ static void tos_tg_save(const void *ip, const struct xt_entry_target *target)
 	printf(" --set-tos 0x%02x/0x%02x", info->tos_value, info->tos_mask);
 }
 
+static int tos_xlate(struct xt_xlate *xl,
+		     const struct xt_xlate_tg_params *params)
+{
+	const struct ipt_tos_target_info *info = 
+			(struct ipt_tos_target_info *) params->target->data;
+	xt_xlate_add(xl, " --set-tos 0x%02x", info->tos);
+
+	return 1;
+}
+
+static int tos_xlate6(struct xt_xlate *xl,
+		     const struct xt_xlate_tg_params *params)
+{
+	const struct xt_tos_target_info *info = 
+			(struct xt_tos_target_info *) params->target->data;
+	xt_xlate_add(xl, " --set-tos 0x%02x/0x%02x", info->tos_value, info->tos_mask);
+
+	return 1;
+}
+
 static struct xtables_target tos_tg_reg[] = {
 	{
 		.version       = XTABLES_VERSION,
@@ -197,6 +217,7 @@ static struct xtables_target tos_tg_reg[] = {
 		.x6_parse      = tos_tg_parse_v0,
 		.x6_fcheck     = tos_tg_check,
 		.x6_options    = tos_tg_opts_v0,
+		.xlate	       = tos_xlate,
 	},
 	{
 		.version       = XTABLES_VERSION,
@@ -211,6 +232,7 @@ static struct xtables_target tos_tg_reg[] = {
 		.x6_parse      = tos_tg_parse,
 		.x6_fcheck     = tos_tg_check,
 		.x6_options    = tos_tg_opts,
+		.xlate	       = tos_xlate6,
 	},
 };
 
-- 
2.7.4

Re: [RFC] extensions: libxt_TOS: Add translation to nft

[Florian Westphal]

Gargi Sharma <gs051095@gmail.com> wrote:
> Add translation for TOS to nftables.
> 
> Examples:
> 
> $ iptables-translate -t mangle -A PREROUTING -p TCP --dport 22 -j TOS --set-tos 0x10
> nft add rule ip mangle PREROUTING tcp dport 22 counter --set-tos 0x10/0xff
> 
> $ iptables-translate -A PREROUTING -t mangle -p tcp --sport ftp-data -j TOS --set-tos 0x02/0x10
> nft add rule ip mangle PREROUTING tcp sport 20 counter --set-tos 0x02/0x10

You did not test this :-/

nft add rule ip mangle PREROUTING tcp sport 20 counter --set-tos 0x02/0x10
nft: unrecognized option '--set-tos'

besides, there is no TOS support in nftables.
Please look at xt_DSCP.c and the xlate function there.

You could rewrite -j TOS iptables rules to their corresponding dscp
eqivalent in some cases at least.

Re: [RFC] extensions: libxt_TOS: Add translation to nft

[Gargi Sharma]

On Tue, Mar 28, 2017 at 9:22 PM, Florian Westphal <fw@strlen.de> wrote:
> Gargi Sharma <gs051095@gmail.com> wrote:
>> Add translation for TOS to nftables.
>>
>> Examples:
>>
>> $ iptables-translate -t mangle -A PREROUTING -p TCP --dport 22 -j TOS --set-tos 0x10
>> nft add rule ip mangle PREROUTING tcp dport 22 counter --set-tos 0x10/0xff
>>
>> $ iptables-translate -A PREROUTING -t mangle -p tcp --sport ftp-data -j TOS --set-tos 0x02/0x10
>> nft add rule ip mangle PREROUTING tcp sport 20 counter --set-tos 0x02/0x10
>
> You did not test this :-/
>
Sorry! I realised this after sending this patch.

> nft add rule ip mangle PREROUTING tcp sport 20 counter --set-tos 0x02/0x10
> nft: unrecognized option '--set-tos'
>
> besides, there is no TOS support in nftables.
> Please look at xt_DSCP.c and the xlate function there.
>
>From what I gather, the first 6 bits are used for DSCP and the last 2 for ecn.
Should I write both dscp and ecn equivalent for the TOS specified?

Thanks,
Gargi
> You could rewrite -j TOS iptables rules to their corresponding dscp
> eqivalent in some cases at least.