extensions: libip6t_icmp6: Add translation to nft

Add translation for icmpv6 to nftables.

Not supported icmp codes in nftables are: no-route,
communication-prohibited, beyond-scope, address-unreachable,
port-unreachable, failed-policy, reject-route, ttl-zero-during-transit,
ttl-zero-during-reassembly, bad-header, unknown-header-type and
unknown-option.

Examples:

$ ip6tables-translate -t filter -A INPUT -m icmp6 --icmpv6-type 1 -j LOG
nft add rule ip6 filter INPUT icmpv6 type destination-unreachable counter log level warn

$ ip6tables-translate -t filter -A INPUT -m icmp6 --icmpv6-type neighbour-advertisement -j LOG
nft add rule ip6 filter INPUT icmpv6 type nd-neighbor-advert counter log level warn

$ ip6tables-translate -t filter -A INPUT -m icmp6 ! --icmpv6-type packet-too-big -j LOG
nft add rule ip6 filter INPUT icmpv6 type != packet-too-big counter log level warn

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

diff --git a/extensions/libip6t_icmp6.c b/extensions/libip6t_icmp6.c
index e183ce6b0882d147891eb3a01a82109a6e2a3cb6..2c5aadd0d42f859617d289378b83fbf254f8d26a 100644 (file)
--- a/extensions/libip6t_icmp6.c
+++ b/extensions/libip6t_icmp6.c
@@ -4,6 +4,7 @@
 #include <xtables.h>
 #include <limits.h> /* INT_MAX in ip6_tables.h */
 #include <linux/netfilter_ipv6/ip6_tables.h>
+#include <netinet/icmp6.h>
 
 enum {
        O_ICMPV6_TYPE = 0,
@@ -222,6 +223,70 @@ static void icmp6_save(const void *ip, const struct xt_entry_match *match)
                printf("/%u", icmpv6->code[0]);
 }
 
+#define XT_ICMPV6_TYPE(type)   (type - ND_ROUTER_SOLICIT)
+
+static const char *icmp6_type_xlate_array[] = {
+       [XT_ICMPV6_TYPE(ND_ROUTER_SOLICIT)]     = "nd-router-solicit",
+       [XT_ICMPV6_TYPE(ND_ROUTER_ADVERT)]      = "nd-router-advert",
+       [XT_ICMPV6_TYPE(ND_NEIGHBOR_SOLICIT)]   = "nd-neighbor-solicit",
+       [XT_ICMPV6_TYPE(ND_NEIGHBOR_ADVERT)]    = "nd-neighbor-advert",
+       [XT_ICMPV6_TYPE(ND_REDIRECT)]           = "nd-redirect",
+};
+
+static const char *icmp6_type_xlate(unsigned int type)
+{
+       if (type < ND_ROUTER_SOLICIT || type > ND_REDIRECT)
+               return NULL;
+
+       return icmp6_type_xlate_array[XT_ICMPV6_TYPE(type)];
+}
+
+static unsigned int type_xlate_print(struct xt_xlate *xl, unsigned int icmptype,
+                                    unsigned int code_min,
+                                    unsigned int code_max)
+{
+       unsigned int i;
+       const char *type_name;
+
+       if (code_min == code_max)
+               return 0;
+
+       type_name = icmp6_type_xlate(icmptype);
+
+       if (type_name) {
+               xt_xlate_add(xl, type_name);
+       } else {
+               for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i)
+                       if (icmpv6_codes[i].type == icmptype &&
+                           icmpv6_codes[i].code_min == code_min &&
+                           icmpv6_codes[i].code_max == code_max)
+                               break;
+
+               if (i != ARRAY_SIZE(icmpv6_codes))
+                       xt_xlate_add(xl, icmpv6_codes[i].name);
+               else
+                       return 0;
+       }
+
+       return 1;
+}
+
+static int icmp6_xlate(const struct xt_entry_match *match, struct xt_xlate *xl,
+                      int numeric)
+{
+       const struct ip6t_icmp *info = (struct ip6t_icmp *)match->data;
+
+       xt_xlate_add(xl, "icmpv6 type%s ",
+                    (info->invflags & IP6T_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 icmp6_mt6_reg = {
        .name           = "icmp6",
        .version        = XTABLES_VERSION,
@@ -234,6 +299,7 @@ static struct xtables_match icmp6_mt6_reg = {
        .save           = icmp6_save,
        .x6_parse       = icmp6_parse,
        .x6_options     = icmp6_opts,
+       .xlate          = icmp6_xlate,
 };
 
 void _init(void)