Add translation for target DNAT to nftables.
Examples:
$ sudo iptables-translate -t nat -A prerouting -p tcp -o eth0 -j DNAT --to-destination 1.2.3.4
nft add rule ip nat prerouting oifname eth0 ip protocol tcp counter dnat 1.2.3.4
$ sudo iptables-translate -t nat -A prerouting -p tcp -d 15.45.23.67 --dport 80 -j DNAT --to-destination 192.168.1.1-192.168.1.10
nft add rule ip nat prerouting ip daddr 15.45.23.67 tcp dport 80 counter dnat 192.168.1.1-192.168.1.10
$ sudo iptables-translate -t nat -A prerouting -p tcp -o eth0 -j DNAT --to-destination 1.2.3.4:1-1023
nft add rule ip nat prerouting oifname eth0 ip protocol tcp counter dnat 1.2.3.4:1-1023
$ sudo iptables-translate -t nat -A prerouting -p tcp -o eth0 -j DNAT --to-destination 1.2.3.4 --random
nft add rule ip nat prerouting oifname eth0 ip protocol tcp counter dnat 1.2.3.4 random
$ sudo iptables-translate -t nat -A prerouting -p tcp -o eth0 -j DNAT --to-destination 1.2.3.4 --random --persistent
nft add rule ip nat prerouting oifname eth0 ip protocol tcp counter dnat 1.2.3.4 random,persistent
Signed-off-by: Shivani Bhardwaj <shivanib134@xxxxxxxxx>
---
Changes in v2:
Fix the code for using comma separator for multiple options
extensions/libipt_DNAT.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/extensions/libipt_DNAT.c b/extensions/libipt_DNAT.c
index ff18799..e529141 100644
--- a/extensions/libipt_DNAT.c
+++ b/extensions/libipt_DNAT.c
@@ -242,6 +242,51 @@ static void DNAT_save(const void *ip, const struct xt_entry_target *target)
}
}
+static void print_range_xlate(const struct nf_nat_ipv4_range *r,
+ struct xt_buf *buf)
+{
+ if (r->flags & NF_NAT_RANGE_MAP_IPS) {
+ struct in_addr a;
+
+ a.s_addr = r->min_ip;
+ xt_buf_add(buf, "%s", xtables_ipaddr_to_numeric(&a));
+ if (r->max_ip != r->min_ip) {
+ a.s_addr = r->max_ip;
+ xt_buf_add(buf, "-%s", xtables_ipaddr_to_numeric(&a));
+ }
+ }
+ if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+ xt_buf_add(buf, ":%hu", ntohs(r->min.tcp.port));
+ if (r->max.tcp.port != r->min.tcp.port)
+ xt_buf_add(buf, "-%hu", ntohs(r->max.tcp.port));
+ }
+}
+
+static int DNAT_xlate(const struct xt_entry_target *target,
+ struct xt_buf *buf, int numeric)
+{
+ const struct ipt_natinfo *info = (const void *)target;
+ unsigned int i = 0;
+ bool sep_need = false;
+ const char *sep = " ";
+
+ for (i = 0; i < info->mr.rangesize; i++) {
+ xt_buf_add(buf, "dnat ");
+ print_range_xlate(&info->mr.range[i], buf);
+ if (info->mr.range[i].flags & NF_NAT_RANGE_PROTO_RANDOM) {
+ xt_buf_add(buf, " random");
+ sep_need = true;
+ }
+ if (info->mr.range[i].flags & NF_NAT_RANGE_PERSISTENT) {
+ if (sep_need)
+ sep = ",";
+ xt_buf_add(buf, "%spersistent", sep);
+ }
+ }
+
+ return 1;
+}
+
static struct xtables_target dnat_tg_reg = {
.name = "DNAT",
.version = XTABLES_VERSION,
@@ -254,6 +299,7 @@ static struct xtables_target dnat_tg_reg = {
.print = DNAT_print,
.save = DNAT_save,
.x6_options = DNAT_opts,
+ .xlate = DNAT_xlate,
};
void _init(void)
--
1.9.1
--
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