diff mbox series

[net-next,v2,6/8] udp: Add support for software checksum and GSO_PARTIAL with GSO offload

Message ID 20180504183039.5194.93287.stgit@localhost.localdomain
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series UDP GSO Segmentation clean-ups | expand

Commit Message

Alexander H Duyck May 4, 2018, 6:31 p.m. UTC 
From: Alexander Duyck <alexander.h.duyck@intel.com>

This patch adds support for a software provided checksum and GSO_PARTIAL
segmentation support. With this we can offload UDP segmentation on devices
that only have partial support for tunnels.

Since we are no longer needing the hardware checksum we can drop the checks
in the segmentation code that were verifying if it was present.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 net/ipv4/udp_offload.c |   28 ++++++++++++++++++----------
 net/ipv6/udp_offload.c |   11 +----------
 2 files changed, 19 insertions(+), 20 deletions(-)

Comments

Willem de Bruijn May 6, 2018, 9:50 p.m. UTC | #1 
On Sat, May 5, 2018 at 3:31 AM, Alexander Duyck
<alexander.duyck@gmail.com> wrote:
> From: Alexander Duyck <alexander.h.duyck@intel.com>
>
> This patch adds support for a software provided checksum and GSO_PARTIAL
> segmentation support. With this we can offload UDP segmentation on devices
> that only have partial support for tunnels.
>
> Since we are no longer needing the hardware checksum we can drop the checks
> in the segmentation code that were verifying if it was present.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
>  net/ipv4/udp_offload.c |   28 ++++++++++++++++++----------
>  net/ipv6/udp_offload.c |   11 +----------
>  2 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> index 946d06d2aa0c..fd94bbb369b2 100644
> --- a/net/ipv4/udp_offload.c
> +++ b/net/ipv4/udp_offload.c
> @@ -217,6 +217,13 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>                 return segs;
>         }
>
> +       /* GSO partial and frag_list segmentation only requires splitting
> +        * the frame into an MSS multiple and possibly a remainder, both
> +        * cases return a GSO skb. So update the mss now.
> +        */
> +       if (skb_is_gso(segs))
> +               mss *= skb_shinfo(segs)->gso_segs;
> +
>         seg = segs;
>         uh = udp_hdr(seg);
>
> @@ -237,6 +244,11 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>                 uh->len = newlen;
>                 uh->check = check;
>
> +               if (seg->ip_summed == CHECKSUM_PARTIAL)
> +                       gso_reset_checksum(seg, ~check);
> +               else
> +                       uh->check = gso_make_checksum(seg, ~check);

Here and below, this needs

  if (uh->check == 0)
    uh->check = CSUM_MANGLED_0;

similar to __skb_udp_tunnel_segment?
Alexander H Duyck May 6, 2018, 10:13 p.m. UTC | #2 
On Sun, May 6, 2018 at 2:50 PM, Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
> On Sat, May 5, 2018 at 3:31 AM, Alexander Duyck
> <alexander.duyck@gmail.com> wrote:
>> From: Alexander Duyck <alexander.h.duyck@intel.com>
>>
>> This patch adds support for a software provided checksum and GSO_PARTIAL
>> segmentation support. With this we can offload UDP segmentation on devices
>> that only have partial support for tunnels.
>>
>> Since we are no longer needing the hardware checksum we can drop the checks
>> in the segmentation code that were verifying if it was present.
>>
>> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
>> ---
>>  net/ipv4/udp_offload.c |   28 ++++++++++++++++++----------
>>  net/ipv6/udp_offload.c |   11 +----------
>>  2 files changed, 19 insertions(+), 20 deletions(-)
>>
>> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
>> index 946d06d2aa0c..fd94bbb369b2 100644
>> --- a/net/ipv4/udp_offload.c
>> +++ b/net/ipv4/udp_offload.c
>> @@ -217,6 +217,13 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>>                 return segs;
>>         }
>>
>> +       /* GSO partial and frag_list segmentation only requires splitting
>> +        * the frame into an MSS multiple and possibly a remainder, both
>> +        * cases return a GSO skb. So update the mss now.
>> +        */
>> +       if (skb_is_gso(segs))
>> +               mss *= skb_shinfo(segs)->gso_segs;
>> +
>>         seg = segs;
>>         uh = udp_hdr(seg);
>>
>> @@ -237,6 +244,11 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>>                 uh->len = newlen;
>>                 uh->check = check;
>>
>> +               if (seg->ip_summed == CHECKSUM_PARTIAL)
>> +                       gso_reset_checksum(seg, ~check);
>> +               else
>> +                       uh->check = gso_make_checksum(seg, ~check);
>
> Here and below, this needs
>
>   if (uh->check == 0)
>     uh->check = CSUM_MANGLED_0;
>
> similar to __skb_udp_tunnel_segment?

Good call, though I think I might change this up a bit and do something like:
uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;

That way I can avoid the extra read.

Thanks.

- Alex
diff mbox series

Patch

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 946d06d2aa0c..fd94bbb369b2 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -217,6 +217,13 @@  struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 		return segs;
 	}
 
+	/* GSO partial and frag_list segmentation only requires splitting
+	 * the frame into an MSS multiple and possibly a remainder, both
+	 * cases return a GSO skb. So update the mss now.
+	 */
+	if (skb_is_gso(segs))
+		mss *= skb_shinfo(segs)->gso_segs;
+
 	seg = segs;
 	uh = udp_hdr(seg);
 
@@ -237,6 +244,11 @@  struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 		uh->len = newlen;
 		uh->check = check;
 
+		if (seg->ip_summed == CHECKSUM_PARTIAL)
+			gso_reset_checksum(seg, ~check);
+		else
+			uh->check = gso_make_checksum(seg, ~check);
+
 		seg = seg->next;
 		uh = udp_hdr(seg);
 	}
@@ -250,6 +262,11 @@  struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 	uh->len = newlen;
 	uh->check = check;
 
+	if (seg->ip_summed == CHECKSUM_PARTIAL)
+		gso_reset_checksum(seg, ~check);
+	else
+		uh->check = gso_make_checksum(seg, ~check);
+
 	/* update refcount for the packet */
 	refcount_add(sum_truesize - gso_skb->truesize, &sk->sk_wmem_alloc);
 out:
@@ -257,15 +274,6 @@  struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 }
 EXPORT_SYMBOL_GPL(__udp_gso_segment);
 
-static struct sk_buff *__udp4_gso_segment(struct sk_buff *gso_skb,
-					  netdev_features_t features)
-{
-	if (!can_checksum_protocol(features, htons(ETH_P_IP)))
-		return ERR_PTR(-EIO);
-
-	return __udp_gso_segment(gso_skb, features);
-}
-
 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
@@ -289,7 +297,7 @@  static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 		goto out;
 
 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
-		return __udp4_gso_segment(skb, features);
+		return __udp_gso_segment(skb, features);
 
 	mss = skb_shinfo(skb)->gso_size;
 	if (unlikely(skb->len <= mss))
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 61e34f1d2fa2..03a2ff3fe1e6 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -17,15 +17,6 @@ 
 #include <net/ip6_checksum.h>
 #include "ip6_offload.h"
 
-static struct sk_buff *__udp6_gso_segment(struct sk_buff *gso_skb,
-					  netdev_features_t features)
-{
-	if (!can_checksum_protocol(features, htons(ETH_P_IPV6)))
-		return ERR_PTR(-EIO);
-
-	return __udp_gso_segment(gso_skb, features);
-}
-
 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
@@ -58,7 +49,7 @@  static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 			goto out;
 
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
-			return __udp6_gso_segment(skb, features);
+			return __udp_gso_segment(skb, features);
 
 		/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
 		 * do checksum of UDP packets sent as multiple IP fragments.