* [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device
@ 2017-12-06 16:38 Alexey Kodanev
2017-12-08 7:02 ` Steffen Klassert
0 siblings, 1 reply; 4+ messages in thread
From: Alexey Kodanev @ 2017-12-06 16:38 UTC (permalink / raw)
To: netdev; +Cc: Steffen Klassert, David Miller, Petr Vorel, Alexey Kodanev
LTP/udp6_ipsec_vti tests fail when sending large UDP datagrams
that require fragmentation and underlying device MTU <= 1500.
This happens because ip6_vti sets mtu to ETH_DATA_LEN and not
updating it depending on a destiantion address.
Futhure attempts to send UDP packets may succeed because pmtu
get updated on ICMPV6_PKT_TOOBIG in vti6_err().
Here is the example when output device MTU set to 9000:
# ip a sh ltp_ns_veth2
ltp_ns_veth2@if7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 ...
inet 10.0.0.2/24 scope global ltp_ns_veth2
inet6 fd00::2/64 scope global
...
# ip li add vti6 type vti6 local fd00::2 remote fd00::1
# ip li show vti6
vti6@NONE: <POINTOPOINT,NOARP> mtu 1500 ...
link/tunnel6 fd00::2 peer fd00::1
After the patch:
# ip li add vti6 type vti6 local fd00::2 remote fd00::1
# ip li show vti6
vti6@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
link/tunnel6 fd00::2 peer fd00::1
Regarding ip_vti, it already tunes mtu with ip_tunnel_bind_dev():
# ip li add vti4 type vti local 10.0.0.2 remote 10.0.0.1
# ip li sh vti4
vti4@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
link/ipip 10.0.0.2 peer 10.0.0.1
Reported-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
---
ip6_vti mtu offset is the same (168) as in ip_vti because ip_vti
offset includes two sizes of struct iphdr: in dev->hard_header_len
and in t_hlen in ip_tunnel_bind_dev(). I'm not sure if it's correct.
net/ipv6/ip6_vti.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index dbb74f3..47e6464 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -638,6 +638,24 @@ static void vti6_link_config(struct ip6_tnl *t)
dev->flags |= IFF_POINTOPOINT;
else
dev->flags &= ~IFF_POINTOPOINT;
+
+ if (p->flags & IP6_TNL_F_CAP_XMIT) {
+ int strict = (ipv6_addr_type(&p->raddr) &
+ (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
+
+ struct rt6_info *rt = rt6_lookup(t->net,
+ &p->raddr, &p->laddr,
+ p->link, strict);
+
+ if (!rt)
+ return;
+
+ if (rt->dst.dev) {
+ dev->mtu = max(rt->dst.dev->mtu - dev->hard_header_len,
+ IPV6_MIN_MTU);
+ }
+ ip6_rt_put(rt);
+ }
}
/**
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device
2017-12-06 16:38 [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device Alexey Kodanev
@ 2017-12-08 7:02 ` Steffen Klassert
2017-12-08 11:54 ` Alexey Kodanev
0 siblings, 1 reply; 4+ messages in thread
From: Steffen Klassert @ 2017-12-08 7:02 UTC (permalink / raw)
To: Alexey Kodanev; +Cc: netdev, David Miller, Petr Vorel
On Wed, Dec 06, 2017 at 07:38:19PM +0300, Alexey Kodanev wrote:
> LTP/udp6_ipsec_vti tests fail when sending large UDP datagrams
> that require fragmentation and underlying device MTU <= 1500.
> This happens because ip6_vti sets mtu to ETH_DATA_LEN and not
> updating it depending on a destiantion address.
>
> Futhure attempts to send UDP packets may succeed because pmtu
> get updated on ICMPV6_PKT_TOOBIG in vti6_err().
>
> Here is the example when output device MTU set to 9000:
>
> # ip a sh ltp_ns_veth2
> ltp_ns_veth2@if7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 ...
> inet 10.0.0.2/24 scope global ltp_ns_veth2
> inet6 fd00::2/64 scope global
> ...
> # ip li add vti6 type vti6 local fd00::2 remote fd00::1
> # ip li show vti6
> vti6@NONE: <POINTOPOINT,NOARP> mtu 1500 ...
> link/tunnel6 fd00::2 peer fd00::1
>
> After the patch:
>
> # ip li add vti6 type vti6 local fd00::2 remote fd00::1
> # ip li show vti6
> vti6@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
> link/tunnel6 fd00::2 peer fd00::1
>
> Regarding ip_vti, it already tunes mtu with ip_tunnel_bind_dev():
>
> # ip li add vti4 type vti local 10.0.0.2 remote 10.0.0.1
> # ip li sh vti4
> vti4@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
> link/ipip 10.0.0.2 peer 10.0.0.1
>
> Reported-by: Petr Vorel <pvorel@suse.cz>
> Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
> ---
>
> ip6_vti mtu offset is the same (168) as in ip_vti because ip_vti
> offset includes two sizes of struct iphdr: in dev->hard_header_len
> and in t_hlen in ip_tunnel_bind_dev(). I'm not sure if it's correct.
>
> net/ipv6/ip6_vti.c | 18 ++++++++++++++++++
> 1 files changed, 18 insertions(+), 0 deletions(-)
>
> diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
> index dbb74f3..47e6464 100644
> --- a/net/ipv6/ip6_vti.c
> +++ b/net/ipv6/ip6_vti.c
> @@ -638,6 +638,24 @@ static void vti6_link_config(struct ip6_tnl *t)
> dev->flags |= IFF_POINTOPOINT;
> else
> dev->flags &= ~IFF_POINTOPOINT;
> +
> + if (p->flags & IP6_TNL_F_CAP_XMIT) {
> + int strict = (ipv6_addr_type(&p->raddr) &
> + (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
> +
> + struct rt6_info *rt = rt6_lookup(t->net,
> + &p->raddr, &p->laddr,
> + p->link, strict);
> +
> + if (!rt)
> + return;
> +
> + if (rt->dst.dev) {
> + dev->mtu = max(rt->dst.dev->mtu - dev->hard_header_len,
> + IPV6_MIN_MTU);
Hm, I'm gettting this when compiling with your patch:
In file included from /home/klassert/git/ipsec-next/include/linux/list.h:9:0,
from /home/klassert/git/ipsec-next/include/linux/module.h:9,
from /home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c:18:
/home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c: In function ‘vti6_link_config’:
/home/klassert/git/ipsec-next/include/linux/kernel.h:808:16: warning: comparison of distinct pointer types lacks a cast
(void) (&max1 == &max2); \
^
/home/klassert/git/ipsec-next/include/linux/kernel.h:817:2: note: in expansion of macro ‘__max’
__max(typeof(x), typeof(y), \
^~~~~
/home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c:654:15: note: in expansion of macro ‘max’
dev->mtu = max(rt->dst.dev->mtu - dev->hard_header_len,
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device
2017-12-08 7:02 ` Steffen Klassert
@ 2017-12-08 11:54 ` Alexey Kodanev
2017-12-08 23:25 ` Shannon Nelson
0 siblings, 1 reply; 4+ messages in thread
From: Alexey Kodanev @ 2017-12-08 11:54 UTC (permalink / raw)
To: Steffen Klassert; +Cc: netdev, David Miller, Petr Vorel
On 12/08/2017 10:02 AM, Steffen Klassert wrote:
> On Wed, Dec 06, 2017 at 07:38:19PM +0300, Alexey Kodanev wrote:
>> LTP/udp6_ipsec_vti tests fail when sending large UDP datagrams
>> that require fragmentation and underlying device MTU <= 1500.
>> This happens because ip6_vti sets mtu to ETH_DATA_LEN and not
>> updating it depending on a destiantion address.
>>
>> Futhure attempts to send UDP packets may succeed because pmtu
>> get updated on ICMPV6_PKT_TOOBIG in vti6_err().
>>
>> Here is the example when output device MTU set to 9000:
>>
>> # ip a sh ltp_ns_veth2
>> ltp_ns_veth2@if7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 ...
>> inet 10.0.0.2/24 scope global ltp_ns_veth2
>> inet6 fd00::2/64 scope global
>> ...
>> # ip li add vti6 type vti6 local fd00::2 remote fd00::1
>> # ip li show vti6
>> vti6@NONE: <POINTOPOINT,NOARP> mtu 1500 ...
>> link/tunnel6 fd00::2 peer fd00::1
>>
>> After the patch:
>>
>> # ip li add vti6 type vti6 local fd00::2 remote fd00::1
>> # ip li show vti6
>> vti6@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
>> link/tunnel6 fd00::2 peer fd00::1
>>
>> Regarding ip_vti, it already tunes mtu with ip_tunnel_bind_dev():
>>
>> # ip li add vti4 type vti local 10.0.0.2 remote 10.0.0.1
>> # ip li sh vti4
>> vti4@NONE: <POINTOPOINT,NOARP> mtu 8832 ...
>> link/ipip 10.0.0.2 peer 10.0.0.1
>>
>> Reported-by: Petr Vorel <pvorel@suse.cz>
>> Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
>> ---
>>
>> ip6_vti mtu offset is the same (168) as in ip_vti because ip_vti
>> offset includes two sizes of struct iphdr: in dev->hard_header_len
>> and in t_hlen in ip_tunnel_bind_dev(). I'm not sure if it's correct.
>>
>> net/ipv6/ip6_vti.c | 18 ++++++++++++++++++
>> 1 files changed, 18 insertions(+), 0 deletions(-)
>>
>> diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
>> index dbb74f3..47e6464 100644
>> --- a/net/ipv6/ip6_vti.c
>> +++ b/net/ipv6/ip6_vti.c
>> @@ -638,6 +638,24 @@ static void vti6_link_config(struct ip6_tnl *t)
>> dev->flags |= IFF_POINTOPOINT;
>> else
>> dev->flags &= ~IFF_POINTOPOINT;
>> +
>> + if (p->flags & IP6_TNL_F_CAP_XMIT) {
>> + int strict = (ipv6_addr_type(&p->raddr) &
>> + (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
>> +
>> + struct rt6_info *rt = rt6_lookup(t->net,
>> + &p->raddr, &p->laddr,
>> + p->link, strict);
>> +
>> + if (!rt)
>> + return;
>> +
>> + if (rt->dst.dev) {
>> + dev->mtu = max(rt->dst.dev->mtu - dev->hard_header_len,
>> + IPV6_MIN_MTU);
>
> Hm, I'm gettting this when compiling with your patch:
>
> In file included from /home/klassert/git/ipsec-next/include/linux/list.h:9:0,
> from /home/klassert/git/ipsec-next/include/linux/module.h:9,
> from /home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c:18:
> /home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c: In function ‘vti6_link_config’:
> /home/klassert/git/ipsec-next/include/linux/kernel.h:808:16: warning: comparison of distinct pointer types lacks a cast
> (void) (&max1 == &max2); \
> ^
> /home/klassert/git/ipsec-next/include/linux/kernel.h:817:2: note: in expansion of macro ‘__max’
> __max(typeof(x), typeof(y), \
> ^~~~~
> /home/klassert/git/ipsec-next/net/ipv6/ip6_vti.c:654:15: note: in expansion of macro ‘max’
> dev->mtu = max(rt->dst.dev->mtu - dev->hard_header_len,
>
rt->dst.dev->mtu and dev->hard_header_len are both unsigned and
IPV6_MIN_MTU considered as int, I guess IPV6_MIN_MTU can be changed
to dev->min_mtu as it is set to the same value in setup, but checking
in the way it is done in ip6_tnl_link_config() looks better.
I'll send 2nd version.
Thanks,
Alexey
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device
2017-12-08 11:54 ` Alexey Kodanev
@ 2017-12-08 23:25 ` Shannon Nelson
0 siblings, 0 replies; 4+ messages in thread
From: Shannon Nelson @ 2017-12-08 23:25 UTC (permalink / raw)
To: Alexey Kodanev, Steffen Klassert; +Cc: netdev, David Miller, Petr Vorel
On 12/8/2017 3:54 AM, Alexey Kodanev wrote:
> On 12/08/2017 10:02 AM, Steffen Klassert wrote:
>> On Wed, Dec 06, 2017 at 07:38:19PM +0300, Alexey Kodanev wrote:
Since you're planning to do a 2nd version anyway, can we get a couple of
the commit message issues cleaned up?
>>> LTP/udp6_ipsec_vti tests fail when sending large UDP datagrams
>>> that require fragmentation and underlying device MTU <= 1500.
s/underlying device/the underlying device has/
>>> This happens because ip6_vti sets mtu to ETH_DATA_LEN and not
>>> updating it depending on a destiantion address.
s/destiantion/destination/
>>>
>>> Futhure attempts to send UDP packets may succeed because pmtu
s/Futhure/Further/
>>> get updated on ICMPV6_PKT_TOOBIG in vti6_err().
s/get/gets/
>>>
>>> Here is the example when output device MTU set to 9000:
s/output device MTU/the output device MTU is/
Thanks,
sln
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-12-06 16:38 [PATCH net-next] ip6_vti: adjust vti mtu according to mtu of output device Alexey Kodanev
2017-12-08 7:02 ` Steffen Klassert
2017-12-08 11:54 ` Alexey Kodanev
2017-12-08 23:25 ` Shannon Nelson
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