loopback routes pinned by commit r326012 for FreeBSD 10 cannot be deleted

[Eugene Grosbein]

24.02.2018 19:37, Andreas Longwitz wrote:

>> Please test the follwoind patch for the kernel:
>>
>> --- sys/net/if.c.orig	2018-02-24 08:00:34.578670000 +0700
>> +++ sys/net/if.c	2018-02-24 11:07:57.014318000 +0700
>> @@ -1699,7 +1699,7 @@ ifa_del_loopback_route(struct ifaddr *if
>>  	null_sdl.sdl_type = ifa->ifa_ifp->if_type;
>>  	null_sdl.sdl_index = ifa->ifa_ifp->if_index;
>>  	bzero(&info, sizeof(info));
>> -	info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC;
>> +	info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC | RTF_PINNED;
>>  	info.rti_info[RTAX_DST] = ia;
>>  	info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&null_sdl;
>>  	error = rtrequest1_fib(RTM_DELETE, &info, NULL, ifa->ifa_ifp->if_fib);
>>
> 
> This patch patch solves the problem for "ifconfig fxp0 delete": now the
> kernel removes the loopback route, tested on FreeBSD 10 r328260.

Glad to know that.

> But deleting the loopback route manually does not work anymore, is this
> intended behaviour ?
> 
> I would like to control the routing table as much as possible.

This is side effect of loopback routes being intentionally protected with RTF_PINNED flag
in recent FreeBSD versions so that link routes can override ones installed by routing daemons.

Perhaps, ifconfig(8) utility should be extended to use RTF_PINNED to be able to modify such routes.