[PATCH nf-next v2 9/9] netfilter: nft_redir: add support for shifted port-ranges

[Jeremy Sowden <jeremy@xxxxxxxxxx>]

Support was recently added to nft_nat to allow shifting port-ranges
during NAT.  Extend this support to allow them to used in redirecting
as well.

Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
---
 include/uapi/linux/netfilter/nf_tables.h |  2 ++
 net/netfilter/nf_nat_redirect.c          |  1 +
 net/netfilter/nft_redir.c                | 23 ++++++++++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index bab3e3c6de74..7249b67acd67 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1488,12 +1488,14 @@ enum nft_masq_attributes {
  * @NFTA_REDIR_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
  * @NFTA_REDIR_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
  * @NFTA_REDIR_FLAGS: NAT flags (see NF_NAT_RANGE_* in linux/netfilter/nf_nat.h) (NLA_U32)
+ * @NFTA_REDIR_REG_PROTO_BASE: source register of proto range base offset (NLA_U32: nft_registers)
  */
 enum nft_redir_attributes {
 	NFTA_REDIR_UNSPEC,
 	NFTA_REDIR_REG_PROTO_MIN,
 	NFTA_REDIR_REG_PROTO_MAX,
 	NFTA_REDIR_FLAGS,
+	NFTA_REDIR_REG_PROTO_BASE,
 	__NFTA_REDIR_MAX
 };
 #define NFTA_REDIR_MAX		(__NFTA_REDIR_MAX - 1)
diff --git a/net/netfilter/nf_nat_redirect.c b/net/netfilter/nf_nat_redirect.c
index 54ce8e6113ed..5641078da2cb 100644
--- a/net/netfilter/nf_nat_redirect.c
+++ b/net/netfilter/nf_nat_redirect.c
@@ -41,6 +41,7 @@ nf_nat_redirect(struct sk_buff *skb, const struct nf_nat_range2 *range,
 	newrange.max_addr	= *newdst;
 	newrange.min_proto	= range->min_proto;
 	newrange.max_proto	= range->max_proto;
+	newrange.base_proto	= range->base_proto;
 
 	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
 }
diff --git a/net/netfilter/nft_redir.c b/net/netfilter/nft_redir.c
index 1d52a05a8b03..adb010c40a07 100644
--- a/net/netfilter/nft_redir.c
+++ b/net/netfilter/nft_redir.c
@@ -16,12 +16,14 @@
 struct nft_redir {
 	u8			sreg_proto_min;
 	u8			sreg_proto_max;
+	u8			sreg_proto_base;
 	u16			flags;
 };
 
 static const struct nla_policy nft_redir_policy[NFTA_REDIR_MAX + 1] = {
 	[NFTA_REDIR_REG_PROTO_MIN]	= { .type = NLA_U32 },
 	[NFTA_REDIR_REG_PROTO_MAX]	= { .type = NLA_U32 },
+	[NFTA_REDIR_REG_PROTO_BASE]	= { .type = NLA_U32 },
 	[NFTA_REDIR_FLAGS]		= { .type = NLA_U32 },
 };
 
@@ -48,7 +50,7 @@ static int nft_redir_init(const struct nft_ctx *ctx,
 	unsigned int plen;
 	int err;
 
-	plen = sizeof_field(struct nf_nat_range, min_addr.all);
+	plen = sizeof_field(struct nf_nat_range2, min_addr.all);
 	if (tb[NFTA_REDIR_REG_PROTO_MIN]) {
 		err = nft_parse_register_load(tb[NFTA_REDIR_REG_PROTO_MIN],
 					      &priv->sreg_proto_min, plen);
@@ -61,6 +63,16 @@ static int nft_redir_init(const struct nft_ctx *ctx,
 						      plen);
 			if (err < 0)
 				return err;
+
+			if (tb[NFTA_REDIR_REG_PROTO_BASE]) {
+				err = nft_parse_register_load
+					(tb[NFTA_REDIR_REG_PROTO_BASE],
+					 &priv->sreg_proto_base, plen);
+				if (err < 0)
+					return err;
+
+				priv->flags |= NF_NAT_RANGE_PROTO_OFFSET;
+			}
 		} else {
 			priv->sreg_proto_max = priv->sreg_proto_min;
 		}
@@ -89,6 +101,11 @@ static int nft_redir_dump(struct sk_buff *skb,
 		if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_MAX,
 				      priv->sreg_proto_max))
 			goto nla_put_failure;
+
+		if (priv->sreg_proto_base)
+			if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_BASE,
+					      priv->sreg_proto_base))
+				goto nla_put_failure;
 	}
 
 	if (priv->flags != 0 &&
@@ -115,6 +132,10 @@ static void nft_redir_eval(const struct nft_expr *expr,
 			nft_reg_load16(&regs->data[priv->sreg_proto_min]);
 		range.max_proto.all = (__force __be16)
 			nft_reg_load16(&regs->data[priv->sreg_proto_max]);
+
+		if (priv->sreg_proto_base)
+			range.base_proto.all = (__force __be16)
+				nft_reg_load16(&regs->data[priv->sreg_proto_base]);
 	}
 
 	switch (nft_pf(pkt)) {
-- 
2.39.2