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/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h
index 3df6a9b..fe7b162 100644 (file)
--- a/include/net/netfilter/nf_tables_core.h
+++ b/include/net/netfilter/nf_tables_core.h
@@ -27,6 +27,15 @@ extern void nft_bitwise_module_exit(void);
 extern int nft_byteorder_module_init(void);
 extern void nft_byteorder_module_exit(void);
 
+struct nft_payload {
+       enum nft_payload_bases  base:8;
+       u8                      offset;
+       u8                      len;
+       enum nft_registers      dreg:8;
+};
+
+extern const struct nft_expr_ops nft_payload_fast_ops;
+
 extern int nft_payload_module_init(void);
 extern void nft_payload_module_exit(void);
 

diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index 2400018..9aede59 100644 (file)
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -32,6 +32,34 @@ static void nft_cmp_fast_eval(const struct nft_expr *expr,
        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 @@ next_rule:
                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)

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index d99db6e..7cf13f7 100644 (file)
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -17,13 +17,6 @@
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
 
-struct nft_payload {
-       enum nft_payload_bases  base:8;
-       u8                      offset;
-       u8                      len;
-       enum nft_registers      dreg:8;
-};
-
 static void nft_payload_eval(const struct nft_expr *expr,
                             struct nft_data data[NFT_REG_MAX + 1],
                             const struct nft_pktinfo *pkt)
@@ -71,27 +64,9 @@ static int nft_payload_init(const struct nft_ctx *ctx,
        struct nft_payload *priv = nft_expr_priv(expr);
        int err;
 
-       if (tb[NFTA_PAYLOAD_DREG] == NULL ||
-           tb[NFTA_PAYLOAD_BASE] == NULL ||
-           tb[NFTA_PAYLOAD_OFFSET] == NULL ||
-           tb[NFTA_PAYLOAD_LEN] == NULL)
-               return -EINVAL;
-
-       priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
-       switch (priv->base) {
-       case NFT_PAYLOAD_LL_HEADER:
-       case NFT_PAYLOAD_NETWORK_HEADER:
-       case NFT_PAYLOAD_TRANSPORT_HEADER:
-               break;
-       default:
-               return -EOPNOTSUPP;
-       }
-
+       priv->base   = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
        priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
        priv->len    = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
-       if (priv->len == 0 ||
-           priv->len > FIELD_SIZEOF(struct nft_data, data))
-               return -EINVAL;
 
        priv->dreg = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_DREG]));
        err = nft_validate_output_register(priv->dreg);
@@ -124,9 +99,49 @@ static const struct nft_expr_ops nft_payload_ops = {
        .dump           = nft_payload_dump,
 };
 
+const struct nft_expr_ops nft_payload_fast_ops = {
+       .type           = &nft_payload_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
+       .eval           = nft_payload_eval,
+       .init           = nft_payload_init,
+       .dump           = nft_payload_dump,
+};
+
+static const struct nft_expr_ops *nft_payload_select_ops(const struct nlattr * const tb[])
+{
+       enum nft_payload_bases base;
+       unsigned int offset, len;
+
+       if (tb[NFTA_PAYLOAD_DREG] == NULL ||
+           tb[NFTA_PAYLOAD_BASE] == NULL ||
+           tb[NFTA_PAYLOAD_OFFSET] == NULL ||
+           tb[NFTA_PAYLOAD_LEN] == NULL)
+               return ERR_PTR(-EINVAL);
+
+       base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
+       switch (base) {
+       case NFT_PAYLOAD_LL_HEADER:
+       case NFT_PAYLOAD_NETWORK_HEADER:
+       case NFT_PAYLOAD_TRANSPORT_HEADER:
+               break;
+       default:
+               return ERR_PTR(-EOPNOTSUPP);
+       }
+
+       offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
+       len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
+       if (len == 0 || len > FIELD_SIZEOF(struct nft_data, data))
+               return ERR_PTR(-EINVAL);
+
+       if (len <= 4 && IS_ALIGNED(offset, len) && base != NFT_PAYLOAD_LL_HEADER)
+               return &nft_payload_fast_ops;
+       else
+               return &nft_payload_ops;
+}
+
 static struct nft_expr_type nft_payload_type __read_mostly = {
        .name           = "payload",
-       .ops            = &nft_payload_ops,
+       .select_ops     = nft_payload_select_ops,
        .policy         = nft_payload_policy,
        .maxattr        = NFTA_PAYLOAD_MAX,
        .owner          = THIS_MODULE,