extensions: libipt_ah: Add translation to nft

Add translation for Authentication Header to nftables.

Examples:

$ sudo iptables-translate -A INPUT -p 51 -m ah --ahspi 500 -j DROP
nft add rule ip filter INPUT ah spi 500 counter drop

$ sudo iptables-translate -A INPUT -p 51 -m ah --ahspi 500:600 -j DROP
nft add rule ip filter INPUT ah spi 500-600 counter drop

$ sudo iptables-translate -A INPUT -p 51 -m ah ! --ahspi 50 -j DROP
nft add rule ip filter INPUT ah spi != 50 counter drop

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/extensions/libipt_ah.c b/extensions/libipt_ah.c
index a490729d414848af59f41900afa6140e8ea13a8e..8973e49c18ba1822b32916ef9f94838971b8db07 100644 (file)
--- a/extensions/libipt_ah.c
+++ b/extensions/libipt_ah.c
@@ -92,18 +92,37 @@ static void ah_save(const void *ip, const struct xt_entry_match *match)
 
 }
 
+static int ah_xlate(const struct xt_entry_match *match,
+                   struct xt_buf *buf, int numeric)
+{
+       const struct ipt_ah *ahinfo = (struct ipt_ah *)match->data;
+
+       if (!(ahinfo->spis[0] == 0 && ahinfo->spis[1] == 0xFFFFFFFF)) {
+               xt_buf_add(buf, "ah spi%s ",
+                          (ahinfo->invflags & IPT_AH_INV_SPI) ? " !=" : "");
+               if (ahinfo->spis[0] != ahinfo->spis[1])
+                       xt_buf_add(buf, "%u-%u ", ahinfo->spis[0],
+                                  ahinfo->spis[1]);
+               else
+                       xt_buf_add(buf, "%u ", ahinfo->spis[0]);
+       }
+
+       return 1;
+}
+
 static struct xtables_match ah_mt_reg = {
-       .name           = "ah",
-       .version        = XTABLES_VERSION,
+       .name           = "ah",
+       .version        = XTABLES_VERSION,
        .family         = NFPROTO_IPV4,
        .size           = XT_ALIGN(sizeof(struct ipt_ah)),
-       .userspacesize  = XT_ALIGN(sizeof(struct ipt_ah)),
-       .help           = ah_help,
+       .userspacesize  = XT_ALIGN(sizeof(struct ipt_ah)),
+       .help           = ah_help,
        .init           = ah_init,
-       .print          = ah_print,
-       .save           = ah_save,
+       .print          = ah_print,
+       .save           = ah_save,
        .x6_parse       = ah_parse,
        .x6_options     = ah_opts,
+       .xlate          = ah_xlate,
 };
 
 void