[PATCH nf-next v2 6/9] netfilter: nft_masq: 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 masquerading
as well.

Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
---
 include/uapi/linux/netfilter/nf_tables.h |  2 ++
 net/netfilter/nf_nat_masquerade.c        |  2 ++
 net/netfilter/nft_masq.c                 | 25 +++++++++++++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index af6032720c78..bab3e3c6de74 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1470,12 +1470,14 @@ enum nft_tproxy_attributes {
  * @NFTA_MASQ_FLAGS: NAT flags (see NF_NAT_RANGE_* in linux/netfilter/nf_nat.h) (NLA_U32)
  * @NFTA_MASQ_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
  * @NFTA_MASQ_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
+ * @NFTA_MASQ_REG_PROTO_BASE: source register of proto range base offset (NLA_U32: nft_registers)
  */
 enum nft_masq_attributes {
 	NFTA_MASQ_UNSPEC,
 	NFTA_MASQ_FLAGS,
 	NFTA_MASQ_REG_PROTO_MIN,
 	NFTA_MASQ_REG_PROTO_MAX,
+	NFTA_MASQ_REG_PROTO_BASE,
 	__NFTA_MASQ_MAX
 };
 #define NFTA_MASQ_MAX		(__NFTA_MASQ_MAX - 1)
diff --git a/net/netfilter/nf_nat_masquerade.c b/net/netfilter/nf_nat_masquerade.c
index 1a506b0c6511..8d40b507d4ad 100644
--- a/net/netfilter/nf_nat_masquerade.c
+++ b/net/netfilter/nf_nat_masquerade.c
@@ -69,6 +69,7 @@ nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
 	newrange.max_addr.ip = newsrc;
 	newrange.min_proto   = range->min_proto;
 	newrange.max_proto   = range->max_proto;
+	newrange.base_proto  = range->base_proto;
 
 	/* Hand modified range to generic setup. */
 	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
@@ -264,6 +265,7 @@ nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
 	newrange.max_addr.in6	= src;
 	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_SRC);
 }
diff --git a/net/netfilter/nft_masq.c b/net/netfilter/nft_masq.c
index 4bd79306eebd..4c46822e5b60 100644
--- a/net/netfilter/nft_masq.c
+++ b/net/netfilter/nft_masq.c
@@ -17,12 +17,14 @@ struct nft_masq {
 	u32			flags;
 	u8			sreg_proto_min;
 	u8			sreg_proto_max;
+	u8			sreg_proto_base;
 };
 
 static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {
 	[NFTA_MASQ_FLAGS]		= { .type = NLA_U32 },
 	[NFTA_MASQ_REG_PROTO_MIN]	= { .type = NLA_U32 },
 	[NFTA_MASQ_REG_PROTO_MAX]	= { .type = NLA_U32 },
+	[NFTA_MASQ_REG_PROTO_BASE]	= { .type = NLA_U32 },
 };
 
 static int nft_masq_validate(const struct nft_ctx *ctx,
@@ -43,7 +45,7 @@ static int nft_masq_init(const struct nft_ctx *ctx,
 			 const struct nft_expr *expr,
 			 const struct nlattr * const tb[])
 {
-	u32 plen = sizeof_field(struct nf_nat_range, min_addr.all);
+	u32 plen = sizeof_field(struct nf_nat_range2, min_addr.all);
 	struct nft_masq *priv = nft_expr_priv(expr);
 	int err;
 
@@ -65,9 +67,21 @@ static int nft_masq_init(const struct nft_ctx *ctx,
 						      plen);
 			if (err < 0)
 				return err;
+
+			if (tb[NFTA_MASQ_REG_PROTO_BASE]) {
+				err = nft_parse_register_load
+					(tb[NFTA_MASQ_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;
 		}
+
+		priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
 	}
 
 	return nf_ct_netns_get(ctx->net, ctx->family);
@@ -88,6 +102,11 @@ static int nft_masq_dump(struct sk_buff *skb,
 		    nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
 				      priv->sreg_proto_max))
 			goto nla_put_failure;
+
+		if (priv->sreg_proto_base)
+			if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_BASE,
+					      priv->sreg_proto_base))
+				goto nla_put_failure;
 	}
 
 	return 0;
@@ -110,6 +129,10 @@ static void nft_masq_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