On Sat, Jan 16, 2021 at 5:36 AM David Ahern <dsah...@gmail.com> wrote: > > On 1/15/21 11:42 AM, Matteo Croce wrote: > > From: Matteo Croce <mcr...@microsoft.com> > > > > 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. > > > > Signed-off-by: Matteo Croce <mcr...@microsoft.com> > > --- > > net/ipv6/addrconf.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > > index eff2cacd5209..19bf6822911c 100644 > > --- a/net/ipv6/addrconf.c > > +++ b/net/ipv6/addrconf.c > > @@ -2469,6 +2469,7 @@ 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); > > > > > What's the motivation for changing this? ie., what s/w cares that it is > kernel vs boot?
A practical example: systemd-networkd explicitly ignores routes with kernel flag[1]. Having a different flag leads the daemon to remove the route sooner or later. [1] https://github.com/systemd/systemd/blob/0b81225e5791f660506f7db0ab88078cf296b771/src/network/networkd-routing-policy-rule.c#L675-L677 -- per aspera ad upstream
