[PATCH next-next 5/6] net: Call skb_checksum_init in IPv6

[PATCH next-next 5/6] net: Call skb_checksum_init in IPv6

[Tom Herbert]

Tested by running 20 netperf TCP_STREAMs with combinations of
LRO on/off, rx-csum-offload on/off, device provide checksum-complete
(emulated) with occasional incorrect value.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/net/ip6_checksum.h |  2 ++
 net/core/checksum.c        |  1 +
 net/ipv6/ip6_checksum.c    | 19 +++++++++----------
 net/ipv6/tcp_ipv6.c        | 21 +--------------------
 4 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index 9e3c540..2df805b 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -41,6 +41,8 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 			__wsum csum);
 #endif
 
+__wsum ip6_pseudo_compute(struct sk_buff *skb, int proto);
+
 static __inline__ __sum16 tcp_v6_check(int len,
 				   const struct in6_addr *saddr,
 				   const struct in6_addr *daddr,
diff --git a/net/core/checksum.c b/net/core/checksum.c
index b0df8c7..33249c3 100644
--- a/net/core/checksum.c
+++ b/net/core/checksum.c
@@ -56,3 +56,4 @@ __sum16 __skb_checksum_validate(struct sk_buff *skb, int proto, bool complete,
 
 	return 0;
 }
+EXPORT_SYMBOL(__skb_checksum_validate);
diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c
index ee7a97f..6105b8f 100644
--- a/net/ipv6/ip6_checksum.c
+++ b/net/ipv6/ip6_checksum.c
@@ -62,6 +62,14 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 EXPORT_SYMBOL(csum_ipv6_magic);
 #endif
 
+__wsum ip6_pseudo_compute(struct sk_buff *skb, int proto)
+{
+	return ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+					    &ipv6_hdr(skb)->daddr,
+					    skb->len, proto, 0));
+}
+EXPORT_SYMBOL(ip6_pseudo_compute);
+
 int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
 {
 	int err;
@@ -84,16 +92,7 @@ int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
 			       &ipv6_hdr(skb)->daddr, ntohs(uh->dest));
 		return 1;
 	}
-	if (skb->ip_summed == CHECKSUM_COMPLETE &&
-	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
-			     skb->len, proto, skb->csum))
-		skb->ip_summed = CHECKSUM_UNNECESSARY;
-
-	if (!skb_csum_unnecessary(skb))
-		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-							 &ipv6_hdr(skb)->daddr,
-							 skb->len, proto, 0));
 
-	return 0;
+	return skb_checksum_init(skb, IPPROTO_UDP, ip6_pseudo_compute);
 }
 EXPORT_SYMBOL(udp6_csum_init);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5ca56ce..ee873e1 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1294,25 +1294,6 @@ out:
 	return NULL;
 }
 
-static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
-{
-	if (skb->ip_summed == CHECKSUM_COMPLETE) {
-		if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
-				  &ipv6_hdr(skb)->daddr, skb->csum)) {
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-			return 0;
-		}
-	}
-
-	skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
-					      &ipv6_hdr(skb)->saddr,
-					      &ipv6_hdr(skb)->daddr, 0));
-
-	if (skb->len <= 76)
-		return __skb_checksum_complete(skb);
-	return 0;
-}
-
 /* The socket must have it's spinlock held when we get
  * here.
  *
@@ -1486,7 +1467,7 @@ static int tcp_v6_rcv(struct sk_buff *skb)
 	if (!pskb_may_pull(skb, th->doff*4))
 		goto discard_it;
 
-	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
+	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_pseudo_compute))
 		goto csum_error;
 
 	th = tcp_hdr(skb);
-- 
1.9.1.423.g4596e3a

Re: [PATCH next-next 5/6] net: Call skb_checksum_init in IPv6

[David Miller]

From: Tom Herbert <therbert@google.com>
Date: Fri, 4 Apr 2014 17:28:09 -0700 (PDT)

> @@ -62,6 +62,14 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
>  EXPORT_SYMBOL(csum_ipv6_magic);
>  #endif
>  
> +__wsum ip6_pseudo_compute(struct sk_buff *skb, int proto)
> +{
> +	return ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
> +					    &ipv6_hdr(skb)->daddr,
> +					    skb->len, proto, 0));
> +}
> +EXPORT_SYMBOL(ip6_pseudo_compute);

Similarly to the ipv4 case this should really be inline.

I see what the problem is, you've made this now a callback so now it
can't be really inlined any more.

That's really a terrible negative to this set of changes, please see
if you can avoid that and inline all of this exactly how it is done
now in the input paths.

Thanks.

Re: [PATCH next-next 5/6] net: Call skb_checksum_init in IPv6

[Tom Herbert]

On Mon, Apr 7, 2014 at 10:15 AM, David Miller <davem@davemloft.net> wrote:
> From: Tom Herbert <therbert@google.com>
> Date: Fri, 4 Apr 2014 17:28:09 -0700 (PDT)
>
>> @@ -62,6 +62,14 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
>>  EXPORT_SYMBOL(csum_ipv6_magic);
>>  #endif
>>
>> +__wsum ip6_pseudo_compute(struct sk_buff *skb, int proto)
>> +{
>> +     return ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
>> +                                         &ipv6_hdr(skb)->daddr,
>> +                                         skb->len, proto, 0));
>> +}
>> +EXPORT_SYMBOL(ip6_pseudo_compute);
>
> Similarly to the ipv4 case this should really be inline.
>
> I see what the problem is, you've made this now a callback so now it
> can't be really inlined any more.
>
> That's really a terrible negative to this set of changes, please see
> if you can avoid that and inline all of this exactly how it is done
> now in the input paths.
>
Okay, but it's going to be hard to do without resorting to macro's I think...

> Thanks.