* [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-04-30 16:11 ` Markus.Amend
0 siblings, 0 replies; 6+ messages in thread
From: Markus.Amend @ 2019-04-30 16:11 UTC (permalink / raw)
To: linux-kernel, netdev, dccp
The current patch modifies the checksum verification of a received DCCP
packet, by adding the function __skb_checksum_validate into the
dccp_vX_rcv routine. The purpose of the modification is to allow the
verification of the skb->ip_summed flags during the checksum validation
process (for checksum offload purposes). As __skb_checksum_validate
covers the functionalities of skb_checksum and dccp_vX_csum_finish they
are needless and therefore removed.
Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
Signed-off-by: Markus Amend <markus.amend@telekom.de>
---
net/dccp/ipv4.c | 6 ++----
net/dccp/ipv6.c | 6 +++---
2 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 26a21d97b6b0..ca4eb93e4663 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -762,9 +762,6 @@ int dccp_invalid_packet(struct sk_buff *skb)
return 1;
}
- /* If header checksum is incorrect, drop packet and return.
- * (This step is completed in the AF-dependent functions.) */
- skb->csum = skb_checksum(skb, 0, cscov, 0);
return 0;
}
@@ -786,7 +783,8 @@ static int dccp_v4_rcv(struct sk_buff *skb)
iph = ip_hdr(skb);
/* Step 1: If header checksum is incorrect, drop packet and return */
- if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
+ if (__skb_checksum_validate(skb, IPPROTO_DCCP,
+ true, false, 0, inet_compute_pseudo)) {
DCCP_WARN("dropped packet with invalid checksum\n");
goto discard_it;
}
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index d5740bad5b18..22df24fecfe7 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -694,9 +694,9 @@ static int dccp_v6_rcv(struct sk_buff *skb)
if (dccp_invalid_packet(skb))
goto discard_it;
- /* Step 1: If header checksum is incorrect, drop packet and return. */
- if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
- &ipv6_hdr(skb)->daddr)) {
+ /* Step 1: If header checksum is incorrect, drop packet and return */
+ if (__skb_checksum_validate(skb, IPPROTO_DCCP,
+ true, false, 0, ip6_compute_pseudo)) {
DCCP_WARN("dropped packet with invalid checksum\n");
goto discard_it;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-04-30 16:11 ` Markus.Amend
0 siblings, 0 replies; 6+ messages in thread
From: Markus.Amend @ 2019-04-30 16:11 UTC (permalink / raw)
To: dccp
The current patch modifies the checksum verification of a received DCCP
packet, by adding the function __skb_checksum_validate into the
dccp_vX_rcv routine. The purpose of the modification is to allow the
verification of the skb->ip_summed flags during the checksum validation
process (for checksum offload purposes). As __skb_checksum_validate
covers the functionalities of skb_checksum and dccp_vX_csum_finish they
are needless and therefore removed.
Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
Signed-off-by: Markus Amend <markus.amend@telekom.de>
---
net/dccp/ipv4.c | 6 ++----
net/dccp/ipv6.c | 6 +++---
2 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 26a21d97b6b0..ca4eb93e4663 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -762,9 +762,6 @@ int dccp_invalid_packet(struct sk_buff *skb)
return 1;
}
- /* If header checksum is incorrect, drop packet and return.
- * (This step is completed in the AF-dependent functions.) */
- skb->csum = skb_checksum(skb, 0, cscov, 0);
return 0;
}
@@ -786,7 +783,8 @@ static int dccp_v4_rcv(struct sk_buff *skb)
iph = ip_hdr(skb);
/* Step 1: If header checksum is incorrect, drop packet and return */
- if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
+ if (__skb_checksum_validate(skb, IPPROTO_DCCP,
+ true, false, 0, inet_compute_pseudo)) {
DCCP_WARN("dropped packet with invalid checksum\n");
goto discard_it;
}
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index d5740bad5b18..22df24fecfe7 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -694,9 +694,9 @@ static int dccp_v6_rcv(struct sk_buff *skb)
if (dccp_invalid_packet(skb))
goto discard_it;
- /* Step 1: If header checksum is incorrect, drop packet and return. */
- if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
- &ipv6_hdr(skb)->daddr)) {
+ /* Step 1: If header checksum is incorrect, drop packet and return */
+ if (__skb_checksum_validate(skb, IPPROTO_DCCP,
+ true, false, 0, ip6_compute_pseudo)) {
DCCP_WARN("dropped packet with invalid checksum\n");
goto discard_it;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-05-05 16:53 ` David Miller
0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2019-05-05 16:53 UTC (permalink / raw)
To: Markus.Amend; +Cc: linux-kernel, netdev, dccp
From: <Markus.Amend@telekom.de>
Date: Tue, 30 Apr 2019 16:11:07 +0000
> The current patch modifies the checksum verification of a received DCCP
> packet, by adding the function __skb_checksum_validate into the
> dccp_vX_rcv routine. The purpose of the modification is to allow the
> verification of the skb->ip_summed flags during the checksum validation
> process (for checksum offload purposes). As __skb_checksum_validate
> covers the functionalities of skb_checksum and dccp_vX_csum_finish they
> are needless and therefore removed.
>
> Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
> Signed-off-by: Markus Amend <markus.amend@telekom.de>
I don't see how this can be correct as you're not taking the csum
coverage value into consideration at all.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-05-05 16:53 ` David Miller
0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2019-05-05 16:53 UTC (permalink / raw)
To: dccp
From: <Markus.Amend@telekom.de>
Date: Tue, 30 Apr 2019 16:11:07 +0000
> The current patch modifies the checksum verification of a received DCCP
> packet, by adding the function __skb_checksum_validate into the
> dccp_vX_rcv routine. The purpose of the modification is to allow the
> verification of the skb->ip_summed flags during the checksum validation
> process (for checksum offload purposes). As __skb_checksum_validate
> covers the functionalities of skb_checksum and dccp_vX_csum_finish they
> are needless and therefore removed.
>
> Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
> Signed-off-by: Markus Amend <markus.amend@telekom.de>
I don't see how this can be correct as you're not taking the csum
coverage value into consideration at all.
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-06-13 6:51 ` Markus.Amend
0 siblings, 0 replies; 6+ messages in thread
From: Markus.Amend @ 2019-06-13 6:51 UTC (permalink / raw)
To: davem; +Cc: linux-kernel, netdev, dccp
Hi David,
Yes, you are right, I overlooked this. Unfortunately the current receive process in the DCCP layer does from my view not properly support the skb->ip_summed flag verification, because the checksum validation takes place at different places. This would require some dirty hacks...
I see two options.
1. Adding the ip_summed flag verification
or 2. Learn from the UDP stack
Since UDP/UDP-Lite are very similar to DCCP, at least from a checksum verification point, I ask myself if it would make sense to re-work DCCP's receive process according to the one of UDP/UDP-Lite?
The relevant process in the udp stack (for IPv4) I identified therefore, can be found in /net/ipv4/udp.c, within the function __udp4_lib_rcv. There it is done, compared to DCCP, the other way round it starts with an udp4_csum_init and most likely a later udp_lib_checksum_complete. Both consider skb->ip_summed. If we would implement similar functions into the DCCP stack and adapt the DCCP rcv checksum validation process to the one in UDP could make probably more sense?!
Personally I prefer the second option, what do you think?
BR
Markus
> -----Original Message-----
> From: David Miller <davem@davemloft.net>
> Sent: Sonntag, 5. Mai 2019 18:53
> To: Amend, Markus <Markus.Amend@telekom.de>
> Cc: linux-kernel@vger.kernel.org; netdev@vger.kernel.org;
> dccp@vger.kernel.org
> Subject: Re: [PATCH v3] net: dccp: Checksum verification enhancement
>
> From: <Markus.Amend@telekom.de>
> Date: Tue, 30 Apr 2019 16:11:07 +0000
>
> > The current patch modifies the checksum verification of a received
> > DCCP packet, by adding the function __skb_checksum_validate into the
> > dccp_vX_rcv routine. The purpose of the modification is to allow the
> > verification of the skb->ip_summed flags during the checksum
> > validation process (for checksum offload purposes). As
> > __skb_checksum_validate covers the functionalities of skb_checksum and
> > dccp_vX_csum_finish they are needless and therefore removed.
> >
> > Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
> > Signed-off-by: Markus Amend <markus.amend@telekom.de>
>
> I don't see how this can be correct as you're not taking the csum coverage
> value into consideration at all.
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH v3] net: dccp: Checksum verification enhancement
@ 2019-06-13 6:51 ` Markus.Amend
0 siblings, 0 replies; 6+ messages in thread
From: Markus.Amend @ 2019-06-13 6:51 UTC (permalink / raw)
To: dccp
Hi David,
Yes, you are right, I overlooked this. Unfortunately the current receive process in the DCCP layer does from my view not properly support the skb->ip_summed flag verification, because the checksum validation takes place at different places. This would require some dirty hacks...
I see two options.
1. Adding the ip_summed flag verification
or 2. Learn from the UDP stack
Since UDP/UDP-Lite are very similar to DCCP, at least from a checksum verification point, I ask myself if it would make sense to re-work DCCP's receive process according to the one of UDP/UDP-Lite?
The relevant process in the udp stack (for IPv4) I identified therefore, can be found in /net/ipv4/udp.c, within the function __udp4_lib_rcv. There it is done, compared to DCCP, the other way round it starts with an udp4_csum_init and most likely a later udp_lib_checksum_complete. Both consider skb->ip_summed. If we would implement similar functions into the DCCP stack and adapt the DCCP rcv checksum validation process to the one in UDP could make probably more sense?!
Personally I prefer the second option, what do you think?
BR
Markus
> -----Original Message-----
> From: David Miller <davem@davemloft.net>
> Sent: Sonntag, 5. Mai 2019 18:53
> To: Amend, Markus <Markus.Amend@telekom.de>
> Cc: linux-kernel@vger.kernel.org; netdev@vger.kernel.org;
> dccp@vger.kernel.org
> Subject: Re: [PATCH v3] net: dccp: Checksum verification enhancement
>
> From: <Markus.Amend@telekom.de>
> Date: Tue, 30 Apr 2019 16:11:07 +0000
>
> > The current patch modifies the checksum verification of a received
> > DCCP packet, by adding the function __skb_checksum_validate into the
> > dccp_vX_rcv routine. The purpose of the modification is to allow the
> > verification of the skb->ip_summed flags during the checksum
> > validation process (for checksum offload purposes). As
> > __skb_checksum_validate covers the functionalities of skb_checksum and
> > dccp_vX_csum_finish they are needless and therefore removed.
> >
> > Signed-off-by: Nathalie Romo Moreno <natha.ro.moreno@gmail.com>
> > Signed-off-by: Markus Amend <markus.amend@telekom.de>
>
> I don't see how this can be correct as you're not taking the csum coverage
> value into consideration at all.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-06-13 16:40 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-30 16:11 [PATCH v3] net: dccp: Checksum verification enhancement Markus.Amend
2019-04-30 16:11 ` Markus.Amend
2019-05-05 16:53 ` David Miller
2019-05-05 16:53 ` David Miller
2019-06-13 6:51 ` Markus.Amend
2019-06-13 6:51 ` Markus.Amend
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