extensions: libipt_icmp: Add translation to nft

Add translation for icmp to nftables. Not supported icmp codes in nftables
are: network-unreachable, host-unreachable, protocol-unreachable,
port-unreachable, fragmentation-needed, source-route-failed,
network-unknown, host-unknown, network-prohibited, host-prohibited,
TOS-network-unreachable, TOS-host-unreachable, communication-prohibited,
host-precedence-violation, precedence-cutoff, network-redirect,
host-redirect, TOS-network-redirect, TOS-host-redirect,
ttl-zero-during-transit, ttl-zero-during-reassembly, ip-header-bad and required-option-missing.

Examples:

$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type echo-reply -j ACCEPT
nft add rule ip filter INPUT icmp type echo-reply counter accept

$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type 3 -j ACCEPT
nft add rule ip filter INPUT icmp type destination-unreachable counter accept

$ sudo iptables-translate -t filter -A INPUT -m icmp ! --icmp-type 3 -j ACCEPT
nft add rule ip filter INPUT icmp type != destination-unreachable counter accept

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

diff --git a/extensions/libipt_icmp.c b/extensions/libipt_icmp.c
index 666e7daf7271df7c54e28b190f50798537ba32be..fb6050a8a1a89a15cbde19411791bb61a2e879cd 100644 (file)
--- a/extensions/libipt_icmp.c
+++ b/extensions/libipt_icmp.c
@@ -249,6 +249,43 @@ static void icmp_save(const void *ip, const struct xt_entry_match *match)
        }
 }
 
+static unsigned int type_xlate_print(struct xt_xlate *xl, unsigned int icmptype,
+                                    unsigned int code_min,
+                                    unsigned int code_max)
+{
+       unsigned int i;
+
+       if (code_min != code_max) {
+               for (i = 0; i < ARRAY_SIZE(icmp_codes); ++i)
+                       if (icmp_codes[i].type == icmptype &&
+                           icmp_codes[i].code_min == code_min &&
+                           icmp_codes[i].code_max == code_max) {
+                               xt_xlate_add(xl, icmp_codes[i].name);
+                               return 1;
+                       }
+       }
+
+       return 0;
+}
+
+static int icmp_xlate(const void *ip, const struct xt_entry_match *match,
+                     struct xt_xlate *xl, int numeric)
+{
+       const struct ipt_icmp *info = (struct ipt_icmp *)match->data;
+
+       if (info->type != 0xFF) {
+               xt_xlate_add(xl, "icmp type%s ",
+                            (info->invflags & IPT_ICMP_INV) ? " !=" : "");
+
+               if (!type_xlate_print(xl, info->type, info->code[0],
+                                     info->code[1]))
+                       return 0;
+
+               xt_xlate_add(xl, " ");
+       }
+       return 1;
+}
+
 static struct xtables_match icmp_mt_reg = {
        .name           = "icmp",
        .version        = XTABLES_VERSION,
@@ -261,6 +298,7 @@ static struct xtables_match icmp_mt_reg = {
        .save           = icmp_save,
        .x6_parse       = icmp_parse,
        .x6_options     = icmp_opts,
+       .xlate          = icmp_xlate,
 };
 
 void _init(void)