netfilter: nftables_offload: VLAN id needs host byteorder in flow dissector

The flow dissector representation expects the VLAN id in host byteorder.
Add the NFT_OFFLOAD_F_NETWORK2HOST flag to swap the bytes from nft_cmp.

Fixes: a82055af5959 ("netfilter: nft_payload: add VLAN offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 39 insertions, 2 deletions

diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index eb6a43a180bb..47b6d05f1ae6 100644
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -114,19 +114,56 @@ nla_put_failure:
 	return -1;
 }
 
+union nft_cmp_offload_data {
+	u16	val16;
+	u32	val32;
+	u64	val64;
+};
+
+static void nft_payload_n2h(union nft_cmp_offload_data *data,
+			    const u8 *val, u32 len)
+{
+	switch (len) {
+	case 2:
+		data->val16 = ntohs(*((u16 *)val));
+		break;
+	case 4:
+		data->val32 = ntohl(*((u32 *)val));
+		break;
+	case 8:
+		data->val64 = be64_to_cpu(*((u64 *)val));
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
 static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
 			     struct nft_flow_rule *flow,
 			     const struct nft_cmp_expr *priv)
 {
 	struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
+	union nft_cmp_offload_data _data, _datamask;
 	u8 *mask = (u8 *)&flow->match.mask;
 	u8 *key = (u8 *)&flow->match.key;
+	u8 *data, *datamask;
 
 	if (priv->op != NFT_CMP_EQ || priv->len > reg->len)
 		return -EOPNOTSUPP;
 
-	memcpy(key + reg->offset, &priv->data, reg->len);
-	memcpy(mask + reg->offset, &reg->mask, reg->len);
+	if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) {
+		nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len);
+		nft_payload_n2h(&_datamask, (u8 *)&reg->mask, reg->len);
+		data = (u8 *)&_data;
+		datamask = (u8 *)&_datamask;
+	} else {
+		data = (u8 *)&priv->data;
+		datamask = (u8 *)&reg->mask;
+	}
+
+	memcpy(key + reg->offset, data, reg->len);
+	memcpy(mask + reg->offset, datamask, reg->len);
 
 	flow->match.dissector.used_keys |= BIT(reg->key);
 	flow->match.dissector.offset[reg->key] = reg->base_offset;