[PATCH] netfilter: nft_meta: Extend support for NFT_META_TSTAMP_NS

[Karuna Grewal <karunagrewal98@xxxxxxxxx>]

Meta evaluation function is extended to suport NFT_META_TSTAMP_NS option
by exposing the 64 bit timestamp of the packet to two 32 bit registers.

Signed-off-by: Karuna Grewal <karunagrewal98@xxxxxxxxx>
---
 include/uapi/linux/netfilter/nf_tables.h | 2 ++
 net/netfilter/nft_meta.c                 | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index a66c8de006cc..61f8f604c614 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -793,6 +793,7 @@ enum nft_exthdr_attributes {
  * @NFT_META_SECPATH: boolean, secpath_exists (!!skb->sp)
  * @NFT_META_IIFKIND: packet input interface kind name (dev->rtnl_link_ops->kind)
  * @NFT_META_OIFKIND: packet output interface kind name (dev->rtnl_link_ops->kind)
+ * @NFT_META_TSTAMP_NS: packet arriavl time (skb->tstamp)
  */
 enum nft_meta_keys {
 	NFT_META_LEN,
@@ -823,6 +824,7 @@ enum nft_meta_keys {
 	NFT_META_SECPATH,
 	NFT_META_IIFKIND,
 	NFT_META_OIFKIND,
+	NFT_META_TSTAMP_NS
 };
 
 /**
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 987d2d6ce624..4eeda9ae8369 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -254,6 +254,13 @@ void nft_meta_get_eval(const struct nft_expr *expr,
 			goto err;
 		strncpy((char *)dest, out->rtnl_link_ops->kind, IFNAMSIZ);
 		break;
+	case NFT_META_TSTAMP_NS:
+		if (skb->tstamp == 0)
+			__net_timestamp((struct sk_buff *)skb);
+		u64 timestamp = ktime_to_ns(skb->tstamp);
+		*dest = (u32) timestamp >> 32;
+		*(dest + 1) = (u32) timestamp;
+		break;
 	default:
 		WARN_ON(1);
 		goto err;
@@ -371,6 +378,8 @@ static int nft_meta_get_init(const struct nft_ctx *ctx,
 		len = IFNAMSIZ;
 		break;
 #endif
+	case NFT_META_TSTAMP_NS:
+		len = sizeof(u64);
 	default:
 		return -EOPNOTSUPP;
 	}
-- 
2.17.1