ipv6: create multicast route with RTPROT_KERNEL

stable inclusion
from stable-5.10.11
commit 3cb2de5242ecddcd80ec7eb9584e3a07a199da2a
bugzilla: 47621

--------------------------------

commit a826b043 upstream.

The ff00::/8 multicast route is created without specifying the fc_protocol
field, so the default RTPROT_BOOT value is used:

  $ ip -6 -d route
  unicast ::1 dev lo proto kernel scope global metric 256 pref medium
  unicast fe80::/64 dev eth0 proto kernel scope global metric 256 pref medium
  unicast ff00::/8 dev eth0 proto boot scope global metric 256 pref medium

As the documentation says, this value identifies routes installed during
boot, but the route is created when interface is set up.
Change the value to RTPROT_KERNEL which is a better value.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NMatteo Croce <mcroce@microsoft.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

net/ipv6/addrconf.c

@@ -2468,6 +2468,7 @@ static void addrconf_add_mroute(struct net_device *dev)
 		.fc_flags = RTF_UP,
 		.fc_type = RTN_UNICAST,
 		.fc_nlinfo.nl_net = dev_net(dev),
+		.fc_protocol = RTPROT_KERNEL,
 	};
 
 	ipv6_addr_set(&cfg.fc_dst, htonl(0xFF000000), 0, 0, 0);