extensions: libxt_ipcomp: Add translation to nft

Add translation of ipcomp to nftables.

First value of the parameter 'ipcompspi' will be translated to 'cpi'
parameter in nftables. Parameter 'compres' is not supported in nftables.

Examples:

$ sudo iptables-translate -t filter -A INPUT -m ipcomp --ipcompspi 0x12 -j ACCEPT
nft add rule ip filter INPUT comp cpi 18 counter accept

$ sudo iptables-translate -t filter -A INPUT -m ipcomp ! --ipcompspi 0x12 -j ACCEPT
nft add rule ip filter INPUT comp cpi != 18 counter accept

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/extensions/libxt_ipcomp.c b/extensions/libxt_ipcomp.c
index b157e7b1420e169d294f1d8a7fcc9eee4698f392..19b251ae188f97336b3546d1190c207fcd880cc4 100644 (file)
--- a/extensions/libxt_ipcomp.c
+++ b/extensions/libxt_ipcomp.c
@@ -95,6 +95,18 @@ static void comp_save(const void *ip, const struct xt_entry_match *match)
                printf(" --compres");
 }
 
+static int comp_xlate(const void *ip, const struct xt_entry_match *match,
+                       struct xt_xlate *xl, int numeric)
+{
+       const struct xt_ipcomp *compinfo = (struct xt_ipcomp *)match->data;
+
+       xt_xlate_add(xl, "comp cpi %s%u ",
+                    (compinfo->invflags & XT_IPCOMP_INV_SPI) ? "!= " : "",
+                    compinfo->spis[0]);
+
+       return 1;
+}
+
 static struct xtables_match comp_mt_reg = {
        .name          = "ipcomp",
        .version       = XTABLES_VERSION,
@@ -106,6 +118,7 @@ static struct xtables_match comp_mt_reg = {
        .save          = comp_save,
        .x6_parse      = comp_parse,
        .x6_options    = comp_opts,
+       .xlate         = comp_xlate,
 };
 
 void