[PATCH v2 xtables] extensions: xt_TPROXY: add txlate support

[PATCH v2 xtables] extensions: xt_TPROXY: add txlate support

[Florian Westphal]

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 v2: add ipv6 test case, use xor instead of or

 extensions/libxt_TPROXY.c      | 59 ++++++++++++++++++++++++++++++++++
 extensions/libxt_TPROXY.txlate | 20 ++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 extensions/libxt_TPROXY.txlate

diff --git a/extensions/libxt_TPROXY.c b/extensions/libxt_TPROXY.c
index d13ec85f92d0..ffc9da1383b8 100644
--- a/extensions/libxt_TPROXY.c
+++ b/extensions/libxt_TPROXY.c
@@ -147,6 +147,62 @@ static void tproxy_tg1_parse(struct xt_option_call *cb)
 	}
 }
 
+static int tproxy_tg_xlate(struct xt_xlate *xl,
+			   const struct xt_tproxy_target_info_v1 *info)
+{
+	int family = xt_xlate_get_family(xl);
+	uint32_t mask = info->mark_mask;
+	bool port_mandatory = false;
+	char buf[INET6_ADDRSTRLEN];
+
+	xt_xlate_add(xl, "tproxy to");
+
+	inet_ntop(family, &info->laddr, buf, sizeof(buf));
+
+	if (family == AF_INET6 && !IN6_IS_ADDR_UNSPECIFIED(&info->laddr.in6))
+		xt_xlate_add(xl, "[%s]", buf);
+	else if (family == AF_INET && info->laddr.ip)
+		xt_xlate_add(xl, "%s", buf);
+	else
+		port_mandatory = true;
+
+	if (port_mandatory)
+		xt_xlate_add(xl, " :%d", ntohs(info->lport));
+	else if (info->lport)
+		xt_xlate_add(xl, ":%d", ntohs(info->lport));
+
+	/* xt_TPROXY.c does: skb->mark = (skb->mark & ~mark_mask) ^ mark_value */
+	if (mask == 0xffffffff)
+		xt_xlate_add(xl, "meta mark set 0x%x", info->mark_value);
+	else if (mask || info->mark_value)
+		xt_xlate_add(xl, "meta mark set meta mark & 0x%x xor 0x%x",
+			     ~mask, info->mark_value);
+
+	return 1;
+}
+
+static int tproxy_tg_xlate_v1(struct xt_xlate *xl,
+			      const struct xt_xlate_tg_params *params)
+{
+	const struct xt_tproxy_target_info_v1 *data = (const void *)params->target->data;
+
+	return tproxy_tg_xlate(xl, data);
+}
+
+static int tproxy_tg_xlate_v0(struct xt_xlate *xl,
+			      const struct xt_xlate_tg_params *params)
+{
+	const struct xt_tproxy_target_info *info = (const void *)params->target->data;
+	struct xt_tproxy_target_info_v1 t = {
+		.mark_mask = info->mark_mask,
+		.mark_value = info->mark_value,
+		.laddr.ip = info->laddr,
+		.lport = info->lport,
+	};
+
+	return tproxy_tg_xlate(xl, &t);
+}
+
 static struct xtables_target tproxy_tg_reg[] = {
 	{
 		.name          = "TPROXY",
@@ -160,6 +216,7 @@ static struct xtables_target tproxy_tg_reg[] = {
 		.save          = tproxy_tg_save,
 		.x6_options    = tproxy_tg0_opts,
 		.x6_parse      = tproxy_tg0_parse,
+		.xlate	       = tproxy_tg_xlate_v0,
 	},
 	{
 		.name          = "TPROXY",
@@ -173,6 +230,7 @@ static struct xtables_target tproxy_tg_reg[] = {
 		.save          = tproxy_tg_save4,
 		.x6_options    = tproxy_tg1_opts,
 		.x6_parse      = tproxy_tg1_parse,
+		.xlate	       = tproxy_tg_xlate_v1,
 	},
 	{
 		.name          = "TPROXY",
@@ -186,6 +244,7 @@ static struct xtables_target tproxy_tg_reg[] = {
 		.save          = tproxy_tg_save6,
 		.x6_options    = tproxy_tg1_opts,
 		.x6_parse      = tproxy_tg1_parse,
+		.xlate	       = tproxy_tg_xlate_v1,
 	},
 };
 
diff --git a/extensions/libxt_TPROXY.txlate b/extensions/libxt_TPROXY.txlate
new file mode 100644
index 000000000000..239bbe0dc8f9
--- /dev/null
+++ b/extensions/libxt_TPROXY.txlate
@@ -0,0 +1,20 @@
+iptables-translate -t mangle -A PREROUTING -p tcp -j TPROXY --on-port 12345 --on-ip 10.0.0.1 --tproxy-mark 0x23/0xff
+nft 'add rule ip mangle PREROUTING ip protocol tcp counter tproxy to 10.0.0.1:12345 meta mark set meta mark & 0xffffff00 xor 0x23'
+
+iptables-translate -t mangle -A PREROUTING -p udp -j TPROXY --on-port 12345 --on-ip 10.0.0.1 --tproxy-mark 0x23
+nft 'add rule ip mangle PREROUTING ip protocol udp counter tproxy to 10.0.0.1:12345 meta mark set 0x23'
+
+iptables-translate -t mangle -A PREROUTING -p udp -j TPROXY --on-port 12345 --on-ip 10.0.0.1
+nft 'add rule ip mangle PREROUTING ip protocol udp counter tproxy to 10.0.0.1:12345'
+
+iptables-translate -t mangle -A PREROUTING -p udp -j TPROXY --on-ip 10.0.0.1 --on-port 0
+nft 'add rule ip mangle PREROUTING ip protocol udp counter tproxy to 10.0.0.1'
+
+iptables-translate -t mangle -A PREROUTING -p tcp -j TPROXY --on-port 12345
+nft 'add rule ip mangle PREROUTING ip protocol tcp counter tproxy to :12345'
+
+iptables-translate -t mangle -A PREROUTING -p tcp -j TPROXY --on-port 0
+nft 'add rule ip mangle PREROUTING ip protocol tcp counter tproxy to :0'
+
+ip6tables-translate -t mangle -A PREROUTING -p tcp -j TPROXY --on-port 12345 --on-ip dead::beef --tproxy-mark 0x23/0xffff
+nft 'add rule ip6 mangle PREROUTING meta l4proto tcp counter tproxy to [dead::beef]:12345 meta mark set meta mark & 0xffff0000 xor 0x23'
-- 
2.44.0

Re: [PATCH v2 xtables] extensions: xt_TPROXY: add txlate support

[Phil Sutter]

On Fri, Mar 08, 2024 at 03:24:28PM +0100, Florian Westphal wrote:
> Signed-off-by: Florian Westphal <fw@strlen.de>

Patch applied, thanks!