ip/ip6_gre: Fix non-point-to-point tunnel not generating IPv6 link local address
authorThomas Winter <Thomas.Winter@alliedtelesis.co.nz>
Tue, 31 Jan 2023 03:46:46 +0000 (16:46 +1300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 9 Feb 2023 10:28:09 +0000 (11:28 +0100)
commit848b6074654e88a543945f258c248bd538c9b5b7
tree2782d5b4b216da65fe548426d8fdf9f642c54ebc
parentabac37d8f90c7f1427e0890c5dc97cb62a1ef212
ip/ip6_gre: Fix non-point-to-point tunnel not generating IPv6 link local address

[ Upstream commit 30e2291f61f93f7132c060190f8360df52644ec1 ]

We recently found that our non-point-to-point tunnels were not
generating any IPv6 link local address and instead generating an
IPv6 compat address, breaking IPv6 communication on the tunnel.

Previously, addrconf_gre_config always would call addrconf_addr_gen
and generate a EUI64 link local address for the tunnel.
Then commit e5dd729460ca changed the code path so that add_v4_addrs
is called but this only generates a compat IPv6 address for
non-point-to-point tunnels.

I assume the compat address is specifically for SIT tunnels so
have kept that only for SIT - GRE tunnels now always generate link
local addresses.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Thomas Winter <Thomas.Winter@alliedtelesis.co.nz>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/ipv6/addrconf.c