netfilter: nft_meta: move pkttype handling to helper

When pkttype is loopback, nft_meta performs guesswork to detect
broad/multicast packets. Place this in a helper, this is hardly a hot path.

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 ba74f3e..fe49b27 100644 (file)
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -76,6 +76,56 @@ nft_meta_get_eval_time(enum nft_meta_keys key,
        }
 }
 
+static noinline bool
+nft_meta_get_eval_pkttype_lo(const struct nft_pktinfo *pkt,
+                            u32 *dest)
+{
+       const struct sk_buff *skb = pkt->skb;
+
+       switch (nft_pf(pkt)) {
+       case NFPROTO_IPV4:
+               if (ipv4_is_multicast(ip_hdr(skb)->daddr))
+                       nft_reg_store8(dest, PACKET_MULTICAST);
+               else
+                       nft_reg_store8(dest, PACKET_BROADCAST);
+               break;
+       case NFPROTO_IPV6:
+               nft_reg_store8(dest, PACKET_MULTICAST);
+               break;
+       case NFPROTO_NETDEV:
+               switch (skb->protocol) {
+               case htons(ETH_P_IP): {
+                       int noff = skb_network_offset(skb);
+                       struct iphdr *iph, _iph;
+
+                       iph = skb_header_pointer(skb, noff,
+                                                sizeof(_iph), &_iph);
+                       if (!iph)
+                               return false;
+
+                       if (ipv4_is_multicast(iph->daddr))
+                               nft_reg_store8(dest, PACKET_MULTICAST);
+                       else
+                               nft_reg_store8(dest, PACKET_BROADCAST);
+
+                       break;
+               }
+               case htons(ETH_P_IPV6):
+                       nft_reg_store8(dest, PACKET_MULTICAST);
+                       break;
+               default:
+                       WARN_ON_ONCE(1);
+                       return false;
+               }
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
+
+       return true;
+}
+
 void nft_meta_get_eval(const struct nft_expr *expr,
                       struct nft_regs *regs,
                       const struct nft_pktinfo *pkt)
@@ -183,46 +233,8 @@ void nft_meta_get_eval(const struct nft_expr *expr,
                        break;
                }
 
-               switch (nft_pf(pkt)) {
-               case NFPROTO_IPV4:
-                       if (ipv4_is_multicast(ip_hdr(skb)->daddr))
-                               nft_reg_store8(dest, PACKET_MULTICAST);
-                       else
-                               nft_reg_store8(dest, PACKET_BROADCAST);
-                       break;
-               case NFPROTO_IPV6:
-                       nft_reg_store8(dest, PACKET_MULTICAST);
-                       break;
-               case NFPROTO_NETDEV:
-                       switch (skb->protocol) {
-                       case htons(ETH_P_IP): {
-                               int noff = skb_network_offset(skb);
-                               struct iphdr *iph, _iph;
-
-                               iph = skb_header_pointer(skb, noff,
-                                                        sizeof(_iph), &_iph);
-                               if (!iph)
-                                       goto err;
-
-                               if (ipv4_is_multicast(iph->daddr))
-                                       nft_reg_store8(dest, PACKET_MULTICAST);
-                               else
-                                       nft_reg_store8(dest, PACKET_BROADCAST);
-
-                               break;
-                       }
-                       case htons(ETH_P_IPV6):
-                               nft_reg_store8(dest, PACKET_MULTICAST);
-                               break;
-                       default:
-                               WARN_ON_ONCE(1);
-                               goto err;
-                       }
-                       break;
-               default:
-                       WARN_ON_ONCE(1);
+               if (!nft_meta_get_eval_pkttype_lo(pkt, dest))
                        goto err;
-               }
                break;
        case NFT_META_CPU:
                *dest = raw_smp_processor_id();