netfilter: nft_payload: add optimized payload implementation for small loads
Add an optimized payload expression implementation for small (up to 4 bytes)
aligned data loads from the linear packet area.
This patch also includes original Patrick McHardy's entitled (nf_tables:
inline nft_payload_fast_eval() into main evaluation loop).
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index 2400018..9aede59 100644
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -32,6 +32,34 @@
data[NFT_REG_VERDICT].verdict = NFT_BREAK;
}
+static bool nft_payload_fast_eval(const struct nft_expr *expr,
+ struct nft_data data[NFT_REG_MAX + 1],
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_payload *priv = nft_expr_priv(expr);
+ const struct sk_buff *skb = pkt->skb;
+ struct nft_data *dest = &data[priv->dreg];
+ unsigned char *ptr;
+
+ if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
+ ptr = skb_network_header(skb);
+ else
+ ptr = skb_transport_header(skb);
+
+ ptr += priv->offset;
+
+ if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
+ return false;
+
+ if (priv->len == 2)
+ *(u16 *)dest->data = *(u16 *)ptr;
+ else if (priv->len == 4)
+ *(u32 *)dest->data = *(u32 *)ptr;
+ else
+ *(u8 *)dest->data = *(u8 *)ptr;
+ return true;
+}
+
unsigned int nft_do_chain(const struct nf_hook_ops *ops,
struct sk_buff *skb,
const struct net_device *in,
@@ -62,7 +90,8 @@
nft_rule_for_each_expr(expr, last, rule) {
if (expr->ops == &nft_cmp_fast_ops)
nft_cmp_fast_eval(expr, data);
- else
+ else if (expr->ops != &nft_payload_fast_ops ||
+ !nft_payload_fast_eval(expr, data, &pkt))
expr->ops->eval(expr, data, &pkt);
if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)