netfilter: nft_meta: place rtclassid handling in a helper

skb_dst is an inline helper with a WARN_ON(), so this is a bit more code
than it looks like.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index ac6fc95..fb1a571 100644 (file)
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -273,6 +273,20 @@ static noinline u32 nft_prandom_u32(void)
        return prandom_u32_state(state);
 }
 
+#ifdef CONFIG_IP_ROUTE_CLASSID
+static noinline bool
+nft_meta_get_eval_rtclassid(const struct sk_buff *skb, u32 *dest)
+{
+       const struct dst_entry *dst = skb_dst(skb);
+
+       if (!dst)
+               return false;
+
+       *dest = dst->tclassid;
+       return true;
+}
+#endif
+
 void nft_meta_get_eval(const struct nft_expr *expr,
                       struct nft_regs *regs,
                       const struct nft_pktinfo *pkt)
@@ -319,14 +333,10 @@ void nft_meta_get_eval(const struct nft_expr *expr,
                        goto err;
                break;
 #ifdef CONFIG_IP_ROUTE_CLASSID
-       case NFT_META_RTCLASSID: {
-               const struct dst_entry *dst = skb_dst(skb);
-
-               if (dst == NULL)
+       case NFT_META_RTCLASSID:
+               if (!nft_meta_get_eval_rtclassid(skb, dest))
                        goto err;
-               *dest = dst->tclassid;
                break;
-       }
 #endif
 #ifdef CONFIG_NETWORK_SECMARK
        case NFT_META_SECMARK: