Re: [PATCH net] ipv6: set fc_protocol with 0 when rtm_protocol is RTPROT_REDIRECT

On Tue, Aug 1, 2017 at 12:12 PM, David Ahern [off-list ref] wrote:

On 7/30/17 9:31 PM, Xin Long wrote:

quoted

quoted

Did you look at removing this hunk from rt6_fill_node:

        if (rt->rt6i_flags & RTF_DYNAMIC)
                rtm->rtm_protocol = RTPROT_REDIRECT;
        else if (rt->rt6i_flags & RTF_ADDRCONF) {
                if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ROUTEINFO))
                        rtm->rtm_protocol = RTPROT_RA;
                else
                        rtm->rtm_protocol = RTPROT_KERNEL;
        }

The issue seems to affect "ip -6 route flush all" as well, not only cache
since 'else if {}' also  causes rtm proto being different from rt6 proto.

quoted

And have rtm_protocol set properly on the route when it is installed?

The codes not keeping rtm proto consistent with rt6 proto day 1,
any idea on why it didn't use rt6 proto in kernel properly?

no, AFAIK it was just an oversight when the original code was written. I
do not know of any reason that would prevent properly setting the
rt6i_protocol in the route when it is allocated.

That's what I was worried about, it might break something,
but double checked, should be fine.

Something like this (not compiled, much less tested):

To respect the old code more, setting RTPROT_RA only when
it's with the flag (ADDRCONF | DEFAULT | ROUTEINFO),
shouldn't it be:

[...]

@@ -2464,6 +2465,7 @@ static struct rt6_info

*rt6_add_route_info(struct net *net,
                .fc_nlinfo.portid = 0,
                .fc_nlinfo.nlh = NULL,
                .fc_nlinfo.nl_net = net,
+               .fc_protocol = RTPROT_KERNEL,
        };

        cfg.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_INFO,

@@ -2471,8 +2473,10 @@ static struct rt6_info

*rt6_add_route_info(struct net *net,
        cfg.fc_gateway = *gwaddr;

        /* We should treat it as a default route if prefix length is 0. */
-       if (!prefixlen)
+       if (!prefixlen) {
+               cfg.fc_protocol = RTPROT_RA;
                cfg.fc_flags |= RTF_DEFAULT;
+       }

        ip6_route_add(&cfg, NULL);

@@ -2516,6 +2520,7 @@ struct rt6_info *rt6_add_dflt_router(const

struct in6_addr *gwaddr,
                .fc_nlinfo.portid = 0,
                .fc_nlinfo.nlh = NULL,
                .fc_nlinfo.nl_net = dev_net(dev),
+               .fc_protocol = RTPROT_KERNEL,
        };
[...]

or you changed it intentionally ?

I will do some testing before posting v2.
thanks for your suggestion. :-)