Add translation for icmpv6 to nftables. Not supported types 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@xxxxxxxxx>
---
v2:
- Detection of not supported types in nftables, as Shivani suggested.
v3:
- Generalize the source code, as Pablo suggested.
extensions/libip6t_icmp6.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/extensions/libip6t_icmp6.c b/extensions/libip6t_icmp6.c
index e183ce6..08eca99 100644
--- a/extensions/libip6t_icmp6.c
+++ b/extensions/libip6t_icmp6.c
@@ -4,6 +4,9 @@
#include <xtables.h>
#include <limits.h> /* INT_MAX in ip6_tables.h */
#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <netinet/icmp6.h>
+
+#define XT_ICMPV6_TYPE(type) (type - ND_ROUTER_SOLICIT)
enum {
O_ICMPV6_TYPE = 0,
@@ -15,6 +18,14 @@ struct icmpv6_names {
uint8_t code_min, code_max;
};
+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 struct icmpv6_names icmpv6_codes[] = {
{ "destination-unreachable", 1, 0, 0xFF },
{ "no-route", 1, 0, 0 },
@@ -222,6 +233,59 @@ static void icmp6_save(const void *ip, const struct xt_entry_match *match)
printf("/%u", icmpv6->code[0]);
}
+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 +298,7 @@ static struct xtables_match icmp6_mt6_reg = {
.save = icmp6_save,
.x6_parse = icmp6_parse,
.x6_options = icmp6_opts,
+ .xlate = icmp6_xlate,
};
void _init(void)
--
2.7.0
--
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