[PATCH 3.16 241/328] bpf, net: add skb_mac_header_len helper

Ben Hutchings
2018-12-09T22:21:24Z

From: Daniel Borkmann <daniel@iogearbox.net>

commit 0daf4349406074fc03e4889ba5e97e6fb5311bab upstream.

Add a small skb_mac_header_len() helper similarly as the
skb_network_header_len() we have and replace open coded
places in BPF's bpf_skb_change_proto() helper. Will also
be used in upcoming work.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: drop changes in bpf]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1801,6 +1801,11 @@ static inline unsigned char *skb_mac_hea
return skb->head + skb->mac_header;
}

+static inline u32 skb_mac_header_len(const struct sk_buff *skb)
+{
+ return skb->network_header - skb->mac_header;
+}
+
static inline int skb_mac_header_was_set(const struct sk_buff *skb)
{
return skb->mac_header != (typeof(skb->mac_header))~0U;