Commit 1e701f16 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller

net: Fix GRE RX to use skb_transport_header for GRE header offset

GRE assumes that the GRE header is at skb_network_header +
ip_hrdlen(skb). It is more general to use skb_transport_header
and this allows the possbility of inserting additional header
between IP and GRE (which is what we will done in Generic UDP
Encapsulation for GRE).
Signed-off-by: default avatarTom Herbert <therbert@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db91b724
......@@ -98,7 +98,6 @@ EXPORT_SYMBOL_GPL(gre_build_header);
static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
bool *csum_err)
{
unsigned int ip_hlen = ip_hdrlen(skb);
const struct gre_base_hdr *greh;
__be32 *options;
int hdr_len;
......@@ -106,7 +105,7 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
return -EINVAL;
greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
greh = (struct gre_base_hdr *)skb_transport_header(skb);
if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
return -EINVAL;
......@@ -116,7 +115,7 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (!pskb_may_pull(skb, hdr_len))
return -EINVAL;
greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
greh = (struct gre_base_hdr *)skb_transport_header(skb);
tpi->proto = greh->protocol;
options = (__be32 *)(greh + 1);
......
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