* Re: [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling
2026-02-08 14:46 [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling Linus Heckemann
@ 2026-02-09 0:56 ` Hangbin Liu
2026-02-09 21:32 ` Ricardo B. Marlière
2026-02-10 13:31 ` Ricardo B. Marlière
2 siblings, 0 replies; 5+ messages in thread
From: Hangbin Liu @ 2026-02-09 0:56 UTC (permalink / raw)
To: Linus Heckemann
Cc: edumazet, davem, eric.dumazet, horms, kuba, morikw2, netdev,
pabeni, syzbot+d4dda070f833dc5dc89a
Hi Linus
On Sun, Feb 08, 2026 at 03:46:04PM +0100, Linus Heckemann wrote:
> 81c734dae203757fb3c9eee6f9896386940776bd was fine in and of itself, but
Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")'
> its backport to 6.12 (and 6.6) broke IPv4-in-IPv6 tunneling, see [1].
> This adds a self-test for basic IPv4-in-IPv6 functionality.
>
> [1]: https://lore.kernel.org/all/CAA2RiuSnH_2xc+-W6EnFEG00XjS-dszMq61JEvRjcGS31CBw=g@mail.gmail.com/
> ---
> tools/testing/selftests/net/Makefile | 1 +
> tools/testing/selftests/net/ip6_tunnel.sh | 41 +++++++++++++++++++++++
> 2 files changed, 42 insertions(+)
> create mode 100644 tools/testing/selftests/net/ip6_tunnel.sh
>
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index 45c4ea381bc36..5037a344ad826 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -43,6 +43,7 @@ TEST_PROGS := \
> io_uring_zerocopy_tx.sh \
> ioam6.sh \
> ip6_gre_headroom.sh \
> + ip6_tunnel.sh \
> ip_defrag.sh \
> ip_local_port_range.sh \
> ipv6_flowlabel.sh \
> diff --git a/tools/testing/selftests/net/ip6_tunnel.sh b/tools/testing/selftests/net/ip6_tunnel.sh
> new file mode 100644
> index 0000000000000..366f4c06cd6a3
> --- /dev/null
> +++ b/tools/testing/selftests/net/ip6_tunnel.sh
> @@ -0,0 +1,41 @@
> +#!/bin/bash
> +# Test that IPv4-over-IPv6 tunneling works.
Maybe tests IPv6-over-IPv6 as well?
> +
> +set -e
> +
> +setup_prepare() {
> + ip link add transport1 type veth peer name transport2
> +
> + ip netns add ns1
net lib has a helper setup_ns()
> + ip link set transport1 netns ns1
> + ip netns exec ns1 bash <<EOF
> + set -e
> + ip address add 2001:db8::1/64 dev transport1 nodad
> + ip link set transport1 up
> + ip link add link transport1 name tunnel1 type ip6tnl mode ipip6 local 2001:db8::1 remote 2001:db8::2
> + ip address add 172.0.0.1/32 peer 172.0.0.2/32 dev tunnel1
> + ip link set tunnel1 up
> +EOF
You can use ip -n $ns_name address/link other than put all the cmds in a inner
bash.
> +
> + ip netns add ns2
> + ip link set transport2 netns ns2
> + ip netns exec ns2 bash <<EOF
> + set -e
> + ip address add 2001:db8::2/64 dev transport2 nodad
> + ip link set transport2 up
> + ip link add link transport2 name tunnel2 type ip6tnl mode ipip6 local 2001:db8::2 remote 2001:db8::1
> + ip address add 172.0.0.2/32 peer 172.0.0.1/32 dev tunnel2
> + ip link set tunnel2 up
> +EOF
Same here
> +}
> +
> +cleanup() {
> + ip netns delete ns1
> + ip netns delete ns2
At the same time cleanup_all_ns() help could be used.
> + # in case the namespaces haven't been set up yet
> + ip link delete transport1
> +}
> +
> +trap cleanup EXIT
> +setup_prepare
> +ip netns exec ns1 ping -W1 -c1 172.0.0.2
> --
> 2.52.0
>
Thanks
Hangbin
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling
2026-02-08 14:46 [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling Linus Heckemann
2026-02-09 0:56 ` Hangbin Liu
@ 2026-02-09 21:32 ` Ricardo B. Marlière
2026-02-09 22:19 ` Ricardo B. Marlière
2026-02-10 13:31 ` Ricardo B. Marlière
2 siblings, 1 reply; 5+ messages in thread
From: Ricardo B. Marlière @ 2026-02-09 21:32 UTC (permalink / raw)
To: Linus Heckemann, edumazet
Cc: davem, eric.dumazet, horms, kuba, morikw2, netdev, pabeni,
syzbot+d4dda070f833dc5dc89a
On Sun Feb 8, 2026 at 11:46 AM -03, Linus Heckemann wrote:
> 81c734dae203757fb3c9eee6f9896386940776bd was fine in and of itself, but
> its backport to 6.12 (and 6.6) broke IPv4-in-IPv6 tunneling, see [1].
> This adds a self-test for basic IPv4-in-IPv6 functionality.
>
> [1]: https://lore.kernel.org/all/CAA2RiuSnH_2xc+-W6EnFEG00XjS-dszMq61JEvRjcGS31CBw=g@mail.gmail.com/
I used this script to test the regression in a clean v6.12 tree with
commit 81c734dae203 ("ip6_tunnel: use skb_vlan_inet_prepare() in
__ip6_tnl_rcv()") applied on top:
# ../ip6_tunnel.sh
PING 172.0.0.2 (172.0.0.2) 56(84) bytes of data.
--- 172.0.0.2 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms
dropwatch shows:
1 drops at __ip6_tnl_rcv+74 (0xffffffffc05c7064) [software]
Now, when also applying commit 4b406f814817 ("net: tunnel: make
skb_vlan_inet_prepare() return drop reasons") on top of that, the issue
goes away. Is there a way to trigger stable to pick this up?
> ---
> tools/testing/selftests/net/Makefile | 1 +
> tools/testing/selftests/net/ip6_tunnel.sh | 41 +++++++++++++++++++++++
> 2 files changed, 42 insertions(+)
> create mode 100644 tools/testing/selftests/net/ip6_tunnel.sh
>
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index 45c4ea381bc36..5037a344ad826 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -43,6 +43,7 @@ TEST_PROGS := \
> io_uring_zerocopy_tx.sh \
> ioam6.sh \
> ip6_gre_headroom.sh \
> + ip6_tunnel.sh \
> ip_defrag.sh \
> ip_local_port_range.sh \
> ipv6_flowlabel.sh \
> diff --git a/tools/testing/selftests/net/ip6_tunnel.sh b/tools/testing/selftests/net/ip6_tunnel.sh
> new file mode 100644
> index 0000000000000..366f4c06cd6a3
> --- /dev/null
> +++ b/tools/testing/selftests/net/ip6_tunnel.sh
> @@ -0,0 +1,41 @@
> +#!/bin/bash
> +# Test that IPv4-over-IPv6 tunneling works.
> +
> +set -e
> +
> +setup_prepare() {
> + ip link add transport1 type veth peer name transport2
> +
> + ip netns add ns1
> + ip link set transport1 netns ns1
> + ip netns exec ns1 bash <<EOF
> + set -e
> + ip address add 2001:db8::1/64 dev transport1 nodad
> + ip link set transport1 up
> + ip link add link transport1 name tunnel1 type ip6tnl mode ipip6 local 2001:db8::1 remote 2001:db8::2
> + ip address add 172.0.0.1/32 peer 172.0.0.2/32 dev tunnel1
> + ip link set tunnel1 up
> +EOF
> +
> + ip netns add ns2
> + ip link set transport2 netns ns2
> + ip netns exec ns2 bash <<EOF
> + set -e
> + ip address add 2001:db8::2/64 dev transport2 nodad
> + ip link set transport2 up
> + ip link add link transport2 name tunnel2 type ip6tnl mode ipip6 local 2001:db8::2 remote 2001:db8::1
> + ip address add 172.0.0.2/32 peer 172.0.0.1/32 dev tunnel2
> + ip link set tunnel2 up
> +EOF
> +}
> +
> +cleanup() {
> + ip netns delete ns1
> + ip netns delete ns2
> + # in case the namespaces haven't been set up yet
> + ip link delete transport1
> +}
> +
> +trap cleanup EXIT
> +setup_prepare
> +ip netns exec ns1 ping -W1 -c1 172.0.0.2
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling
2026-02-09 21:32 ` Ricardo B. Marlière
@ 2026-02-09 22:19 ` Ricardo B. Marlière
0 siblings, 0 replies; 5+ messages in thread
From: Ricardo B. Marlière @ 2026-02-09 22:19 UTC (permalink / raw)
To: Ricardo B. Marlière, Linus Heckemann, edumazet
Cc: davem, eric.dumazet, horms, kuba, morikw2, netdev, pabeni,
syzbot+d4dda070f833dc5dc89a
On Mon Feb 9, 2026 at 6:32 PM -03, Ricardo B. Marlière wrote:
> On Sun Feb 8, 2026 at 11:46 AM -03, Linus Heckemann wrote:
>> 81c734dae203757fb3c9eee6f9896386940776bd was fine in and of itself, but
>> its backport to 6.12 (and 6.6) broke IPv4-in-IPv6 tunneling, see [1].
>> This adds a self-test for basic IPv4-in-IPv6 functionality.
>>
>> [1]: https://lore.kernel.org/all/CAA2RiuSnH_2xc+-W6EnFEG00XjS-dszMq61JEvRjcGS31CBw=g@mail.gmail.com/
>
> I used this script to test the regression in a clean v6.12 tree with
> commit 81c734dae203 ("ip6_tunnel: use skb_vlan_inet_prepare() in
> __ip6_tnl_rcv()") applied on top:
>
>
> # ../ip6_tunnel.sh
> PING 172.0.0.2 (172.0.0.2) 56(84) bytes of data.
>
> --- 172.0.0.2 ping statistics ---
> 1 packets transmitted, 0 received, 100% packet loss, time 0ms
>
>
> dropwatch shows:
>
> 1 drops at __ip6_tnl_rcv+74 (0xffffffffc05c7064) [software]
>
>
> Now, when also applying commit 4b406f814817 ("net: tunnel: make
> skb_vlan_inet_prepare() return drop reasons") on top of that, the issue
oops, that would be 9990ddf47d41 ("net: tunnel: make skb_vlan_inet_prepare() return drop reasons")
> goes away. Is there a way to trigger stable to pick this up?
>
>> ---
>> tools/testing/selftests/net/Makefile | 1 +
>> tools/testing/selftests/net/ip6_tunnel.sh | 41 +++++++++++++++++++++++
>> 2 files changed, 42 insertions(+)
>> create mode 100644 tools/testing/selftests/net/ip6_tunnel.sh
>>
>> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
>> index 45c4ea381bc36..5037a344ad826 100644
>> --- a/tools/testing/selftests/net/Makefile
>> +++ b/tools/testing/selftests/net/Makefile
>> @@ -43,6 +43,7 @@ TEST_PROGS := \
>> io_uring_zerocopy_tx.sh \
>> ioam6.sh \
>> ip6_gre_headroom.sh \
>> + ip6_tunnel.sh \
>> ip_defrag.sh \
>> ip_local_port_range.sh \
>> ipv6_flowlabel.sh \
>> diff --git a/tools/testing/selftests/net/ip6_tunnel.sh b/tools/testing/selftests/net/ip6_tunnel.sh
>> new file mode 100644
>> index 0000000000000..366f4c06cd6a3
>> --- /dev/null
>> +++ b/tools/testing/selftests/net/ip6_tunnel.sh
>> @@ -0,0 +1,41 @@
>> +#!/bin/bash
>> +# Test that IPv4-over-IPv6 tunneling works.
>> +
>> +set -e
>> +
>> +setup_prepare() {
>> + ip link add transport1 type veth peer name transport2
>> +
>> + ip netns add ns1
>> + ip link set transport1 netns ns1
>> + ip netns exec ns1 bash <<EOF
>> + set -e
>> + ip address add 2001:db8::1/64 dev transport1 nodad
>> + ip link set transport1 up
>> + ip link add link transport1 name tunnel1 type ip6tnl mode ipip6 local 2001:db8::1 remote 2001:db8::2
>> + ip address add 172.0.0.1/32 peer 172.0.0.2/32 dev tunnel1
>> + ip link set tunnel1 up
>> +EOF
>> +
>> + ip netns add ns2
>> + ip link set transport2 netns ns2
>> + ip netns exec ns2 bash <<EOF
>> + set -e
>> + ip address add 2001:db8::2/64 dev transport2 nodad
>> + ip link set transport2 up
>> + ip link add link transport2 name tunnel2 type ip6tnl mode ipip6 local 2001:db8::2 remote 2001:db8::1
>> + ip address add 172.0.0.2/32 peer 172.0.0.1/32 dev tunnel2
>> + ip link set tunnel2 up
>> +EOF
>> +}
>> +
>> +cleanup() {
>> + ip netns delete ns1
>> + ip netns delete ns2
>> + # in case the namespaces haven't been set up yet
>> + ip link delete transport1
>> +}
>> +
>> +trap cleanup EXIT
>> +setup_prepare
>> +ip netns exec ns1 ping -W1 -c1 172.0.0.2
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling
2026-02-08 14:46 [PATCH] selftests/net: add test for IPv4-in-IPv6 tunneling Linus Heckemann
2026-02-09 0:56 ` Hangbin Liu
2026-02-09 21:32 ` Ricardo B. Marlière
@ 2026-02-10 13:31 ` Ricardo B. Marlière
2 siblings, 0 replies; 5+ messages in thread
From: Ricardo B. Marlière @ 2026-02-10 13:31 UTC (permalink / raw)
To: Linus Heckemann, edumazet
Cc: davem, eric.dumazet, horms, kuba, morikw2, netdev, pabeni,
syzbot+d4dda070f833dc5dc89a
On Sun Feb 8, 2026 at 11:46 AM -03, Linus Heckemann wrote:
> 81c734dae203757fb3c9eee6f9896386940776bd was fine in and of itself, but
> its backport to 6.12 (and 6.6) broke IPv4-in-IPv6 tunneling, see [1].
> This adds a self-test for basic IPv4-in-IPv6 functionality.
>
> [1]: https://lore.kernel.org/all/CAA2RiuSnH_2xc+-W6EnFEG00XjS-dszMq61JEvRjcGS31CBw=g@mail.gmail.com/
> ---
> tools/testing/selftests/net/Makefile | 1 +
> tools/testing/selftests/net/ip6_tunnel.sh | 41 +++++++++++++++++++++++
> 2 files changed, 42 insertions(+)
> create mode 100644 tools/testing/selftests/net/ip6_tunnel.sh
FWIW,
Tested-by: Ricardo B. Marlière <rbm@suse.com>
>
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index 45c4ea381bc36..5037a344ad826 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -43,6 +43,7 @@ TEST_PROGS := \
> io_uring_zerocopy_tx.sh \
> ioam6.sh \
> ip6_gre_headroom.sh \
> + ip6_tunnel.sh \
> ip_defrag.sh \
> ip_local_port_range.sh \
> ipv6_flowlabel.sh \
> diff --git a/tools/testing/selftests/net/ip6_tunnel.sh b/tools/testing/selftests/net/ip6_tunnel.sh
> new file mode 100644
> index 0000000000000..366f4c06cd6a3
> --- /dev/null
> +++ b/tools/testing/selftests/net/ip6_tunnel.sh
> @@ -0,0 +1,41 @@
> +#!/bin/bash
> +# Test that IPv4-over-IPv6 tunneling works.
> +
> +set -e
> +
> +setup_prepare() {
> + ip link add transport1 type veth peer name transport2
> +
> + ip netns add ns1
> + ip link set transport1 netns ns1
> + ip netns exec ns1 bash <<EOF
> + set -e
> + ip address add 2001:db8::1/64 dev transport1 nodad
> + ip link set transport1 up
> + ip link add link transport1 name tunnel1 type ip6tnl mode ipip6 local 2001:db8::1 remote 2001:db8::2
> + ip address add 172.0.0.1/32 peer 172.0.0.2/32 dev tunnel1
> + ip link set tunnel1 up
> +EOF
> +
> + ip netns add ns2
> + ip link set transport2 netns ns2
> + ip netns exec ns2 bash <<EOF
> + set -e
> + ip address add 2001:db8::2/64 dev transport2 nodad
> + ip link set transport2 up
> + ip link add link transport2 name tunnel2 type ip6tnl mode ipip6 local 2001:db8::2 remote 2001:db8::1
> + ip address add 172.0.0.2/32 peer 172.0.0.1/32 dev tunnel2
> + ip link set tunnel2 up
> +EOF
> +}
> +
> +cleanup() {
> + ip netns delete ns1
> + ip netns delete ns2
> + # in case the namespaces haven't been set up yet
> + ip link delete transport1
> +}
> +
> +trap cleanup EXIT
> +setup_prepare
> +ip netns exec ns1 ping -W1 -c1 172.0.0.2
^ permalink raw reply [flat|nested] 5+ messages in thread