Consider the following command:
ip tunnel add mode vti remote 12.0.0.1 local 12.0.0.3 ikey 15
i_flags will be GRE_KEY|VTI_ISVTI. So, in order to distinguish between ipip and
vti we have to check just VTI_ISVTI bit, not the equality of i_flags and
VTI_ISVTI.
* Note, that there also was a bug in ip_tunnel/ip_vti, see
commit 7c8e6b9c281(ip_vti: Fix 'ip tunnel add' with 'key' parameters),
https://lkml.org/lkml/2014/6/7/125.
Even patched iproute could be unable to create vti tunnels with non-zero keys.
1) Unpatched iproute2:
[root@vm ~]# ip tunnel show
[root@vm ~]# lsmod | egrep '(ipip|vti)'
[root@vm ~]# ip tunnel add mode vti ikey 1
[root@vm ~]# lsmod | egrep '(ipip|vti)'
ipip 4197 0
tunnel4 1659 1 ipip
ip_tunnel 9295 1 ipip
[root@vm ~]# ip tunnel show
tunl0: ip/ip remote any local any ttl inherit
[root@vm ~]# ip tunnel add mode vti remote 1.2.3.4 ikey 2
[root@vm ~]# ip tunnel show
ipip0: ip/ip remote 1.2.3.4 local any ttl inherit
tunl0: ip/ip remote any local any ttl inherit
[root@vm ~]# lsmod | egrep '(ipip|vti)'
ipip 4197 0
tunnel4 1659 1 ipip
ip_tunnel 9295 1 ipip
# ipip tunnels are created instead of vti
2) Patched iproute2:
[root@vm ~]# ip tunnel show
[root@vm ~]# lsmod | egrep '(ipip|vti)'
[root@vm ~]# ip tunnel add mode vti ikey 1
[root@vm ~]# lsmod | egrep '(ipip|vti)'
ip_vti 5258 0
ip_tunnel 9295 1 ip_vti
[root@vm ~]# ip tunnel show
vti0: ip/ip remote any local any ttl inherit ikey 1 okey 0
ip_vti0: ip/ip remote any local any ttl inherit nopmtudisc key 0
[root@vm ~]# ip tunnel add mode vti remote 1.2.3.4 ikey 2
[root@vm ~]# ip tunnel show
vti0: ip/ip remote any local any ttl inherit ikey 1 okey 0
vti1: ip/ip remote 1.2.3.4 local any ttl inherit ikey 2 okey 0
ip_vti0: ip/ip remote any local any ttl inherit nopmtudisc key 0
# Vti tunnels are created as expected
# * If you have unpatched kernel your vti tunnels will have ikey == okey == 0
Same story exists with ip tunnel show/del with non-zero [io]key: requests are
routed to tunl0 instead of ip_vti0.
Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
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