From: Daniel Borkmann <daniel@iogearbox.net>
Date: Sun, 2 Jul 2017 00:13:25 +0000 (+0200)
Subject: bpf, net: add skb_mac_header_len helper
X-Git-Tag: MMI-PSA29.97-13-9~5285^2~27^2~6
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0daf4349406074fc03e4889ba5e97e6fb5311bab;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

bpf, net: add skb_mac_header_len helper

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>
---

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d0b9f3846eab..3d3ceaac13b1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2206,6 +2206,11 @@ static inline int skb_mac_offset(const struct sk_buff *skb)
 	return skb_mac_header(skb) - skb->data;
 }
 
+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;
diff --git a/net/core/filter.c b/net/core/filter.c
index e5c280aa5de6..68d8cd865c4a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2012,7 +2012,7 @@ static int bpf_skb_net_hdr_pop(struct sk_buff *skb, u32 off, u32 len)
 static int bpf_skb_proto_4_to_6(struct sk_buff *skb)
 {
 	const u32 len_diff = sizeof(struct ipv6hdr) - sizeof(struct iphdr);
-	u32 off = skb->network_header - skb->mac_header;
+	u32 off = skb_mac_header_len(skb);
 	int ret;
 
 	ret = skb_cow(skb, len_diff);
@@ -2048,7 +2048,7 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb)
 static int bpf_skb_proto_6_to_4(struct sk_buff *skb)
 {
 	const u32 len_diff = sizeof(struct ipv6hdr) - sizeof(struct iphdr);
-	u32 off = skb->network_header - skb->mac_header;
+	u32 off = skb_mac_header_len(skb);
 	int ret;
 
 	ret = skb_unclone(skb, GFP_ATOMIC);