bpf: reuse dev_is_mac_header_xmit for redirect

Commit dcf80034 ("net/sched: act_mirred: Refactor detection whether
dev needs xmit at mac header") added dev_is_mac_header_xmit(); since it's
also useful elsewhere, move it to if_arp.h and reuse it for BPF.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_arp.h

@@ -44,4 +44,20 @@ static inline int arp_hdr_len(struct net_device *dev)
 		return sizeof(struct arphdr) + (dev->addr_len + sizeof(u32)) * 2;
 	}
 }
+
+static inline bool dev_is_mac_header_xmit(const struct net_device *dev)
+{
+	switch (dev->type) {
+	case ARPHRD_TUNNEL:
+	case ARPHRD_TUNNEL6:
+	case ARPHRD_SIT:
+	case ARPHRD_IPGRE:
+	case ARPHRD_VOID:
+	case ARPHRD_NONE:
+		return false;
+	default:
+		return true;
+	}
+}
+
 #endif	/* _LINUX_IF_ARP_H */

net/core/filter.c

@@ -30,6 +30,7 @@
 #include <linux/inet.h>
 #include <linux/netdevice.h>
 #include <linux/if_packet.h>
+#include <linux/if_arp.h>
 #include <linux/gfp.h>
 #include <net/ip.h>
 #include <net/protocol.h>
@@ -1696,17 +1697,10 @@ static int __bpf_redirect_common(struct sk_buff *skb, struct net_device *dev,
 static int __bpf_redirect(struct sk_buff *skb, struct net_device *dev,
 			  u32 flags)
 {
-	switch (dev->type) {
-	case ARPHRD_TUNNEL:
-	case ARPHRD_TUNNEL6:
-	case ARPHRD_SIT:
-	case ARPHRD_IPGRE:
-	case ARPHRD_VOID:
-	case ARPHRD_NONE:
-		return __bpf_redirect_no_mac(skb, dev, flags);
-	default:
+	if (dev_is_mac_header_xmit(dev))
 		return __bpf_redirect_common(skb, dev, flags);
-	}
+	else
+		return __bpf_redirect_no_mac(skb, dev, flags);
 }
 
 BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags)

net/sched/act_mirred.c

@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/gfp.h>
+#include <linux/if_arp.h>
 #include <net/net_namespace.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
@@ -73,20 +74,6 @@ static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
 static unsigned int mirred_net_id;
 static struct tc_action_ops act_mirred_ops;
 
-static bool dev_is_mac_header_xmit(const struct net_device *dev)
-{
-	switch (dev->type) {
-	case ARPHRD_TUNNEL:
-	case ARPHRD_TUNNEL6:
-	case ARPHRD_SIT:
-	case ARPHRD_IPGRE:
-	case ARPHRD_VOID:
-	case ARPHRD_NONE:
-		return false;
-	}
-	return true;
-}
-
 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 			   struct nlattr *est, struct tc_action **a, int ovr,
 			   int bind)