Re: [net-next PATCH 07/10] gre: Use inner_proto to obtain inner header protocol

[Alexander Duyck]

On Sat, Feb 6, 2016 at 2:55 PM, Tom Herbert  wrote:
> On Fri, Feb 5, 2016 at 3:28 PM, Alexander Duyck  wrote:
>> Instead of parsing headers to determine the inner protocol we can just pull
>> the value from inner_proto.
>>
>> Signed-off-by: Alexander Duyck 
>> ---
>>  net/ipv4/gre_offload.c |6 ++
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
>> index c15441b5ff61..003b0ebbcfdd 100644
>> --- a/net/ipv4/gre_offload.c
>> +++ b/net/ipv4/gre_offload.c
>> @@ -20,7 +20,6 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
>>  {
>> int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
>> struct sk_buff *segs = ERR_PTR(-EINVAL);
>> -   struct gre_base_hdr *greh;
>> u16 mac_offset = skb->mac_header;
>> __be16 protocol = skb->protocol;
>> u16 mac_len = skb->mac_len;
>> @@ -48,15 +47,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff 
>> *skb,
>> if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
>> goto out;
>>
>> -   greh = (struct gre_base_hdr *)skb_transport_header(skb);
>> -
>> /* setup inner skb. */
>> -   skb->protocol = greh->protocol;
>> skb->encapsulation = 0;
>> __skb_pull(skb, tnl_hlen);
>> skb_reset_mac_header(skb);
>> skb_set_network_header(skb, skb_inner_network_offset(skb));
>> skb->mac_len = skb_inner_network_offset(skb);
>> +   skb->protocol = skb->inner_protocol;
>
> Is this going to be a problem if we try to perform GSO with nested
> encapsulations? (I suppose that's something not supported).

Right tunnels don't offload tunnels so there is no need to worry about
a tunnel nested in a tunnel.  We might get there someday, but I don't
see it happening any time soon because we would end up likely needing
yet another level of header pointers for middle mac, network, and
transport in such a case.

- Alex

Re: [net-next PATCH 07/10] gre: Use inner_proto to obtain inner header protocol

[Tom Herbert]

On Fri, Feb 5, 2016 at 3:28 PM, Alexander Duyck  wrote:
> Instead of parsing headers to determine the inner protocol we can just pull
> the value from inner_proto.
>
> Signed-off-by: Alexander Duyck 
> ---
>  net/ipv4/gre_offload.c |6 ++
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
> index c15441b5ff61..003b0ebbcfdd 100644
> --- a/net/ipv4/gre_offload.c
> +++ b/net/ipv4/gre_offload.c
> @@ -20,7 +20,6 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
>  {
> int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
> struct sk_buff *segs = ERR_PTR(-EINVAL);
> -   struct gre_base_hdr *greh;
> u16 mac_offset = skb->mac_header;
> __be16 protocol = skb->protocol;
> u16 mac_len = skb->mac_len;
> @@ -48,15 +47,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff 
> *skb,
> if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
> goto out;
>
> -   greh = (struct gre_base_hdr *)skb_transport_header(skb);
> -
> /* setup inner skb. */
> -   skb->protocol = greh->protocol;
> skb->encapsulation = 0;
> __skb_pull(skb, tnl_hlen);
> skb_reset_mac_header(skb);
> skb_set_network_header(skb, skb_inner_network_offset(skb));
> skb->mac_len = skb_inner_network_offset(skb);
> +   skb->protocol = skb->inner_protocol;

Is this going to be a problem if we try to perform GSO with nested
encapsulations? (I suppose that's something not supported).

>
> need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM);
> skb->encap_hdr_csum = need_csum;
> @@ -75,6 +72,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
> gre_offset = outer_hlen - tnl_hlen;
> skb = segs;
> do {
> +   struct gre_base_hdr *greh;
> __be32 *pcsum;
>
> skb_reset_inner_headers(skb);
>

[net-next PATCH 07/10] gre: Use inner_proto to obtain inner header protocol

[Alexander Duyck]

Instead of parsing headers to determine the inner protocol we can just pull
the value from inner_proto.

Signed-off-by: Alexander Duyck 
---
 net/ipv4/gre_offload.c |6 ++
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index c15441b5ff61..003b0ebbcfdd 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -20,7 +20,6 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 {
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
struct sk_buff *segs = ERR_PTR(-EINVAL);
-   struct gre_base_hdr *greh;
u16 mac_offset = skb->mac_header;
__be16 protocol = skb->protocol;
u16 mac_len = skb->mac_len;
@@ -48,15 +47,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
goto out;
 
-   greh = (struct gre_base_hdr *)skb_transport_header(skb);
-
/* setup inner skb. */
-   skb->protocol = greh->protocol;
skb->encapsulation = 0;
__skb_pull(skb, tnl_hlen);
skb_reset_mac_header(skb);
skb_set_network_header(skb, skb_inner_network_offset(skb));
skb->mac_len = skb_inner_network_offset(skb);
+   skb->protocol = skb->inner_protocol;
 
need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM);
skb->encap_hdr_csum = need_csum;
@@ -75,6 +72,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
gre_offset = outer_hlen - tnl_hlen;
skb = segs;
do {
+   struct gre_base_hdr *greh;
__be32 *pcsum;
 
skb_reset_inner_headers(skb);