if_rtdel: error 47

[Jeremy Chadwick]

On Tue, Aug 31, 2010 at 05:02:20PM -0400, Mike Tancsa wrote:
> On a RELENG_8 box from aug 25th, I started seeing a constant spew of
> 
> Aug 31 00:17:46 gate8 kernel: if_rtdel: error 47
> Aug 31 00:18:29 gate8 kernel: ifa_del_loopback_route: deletion failed
> Aug 31 00:18:29 gate8 kernel: if_rtdel: error 3
> Aug 31 00:18:29 gate8 last message repeated 2 times
> Aug 31 00:18:37 gate8 kernel: ifa_del_loopback_route: deletion failed
> Aug 31 00:18:37 gate8 kernel: if_rtdel: error 3
> Aug 31 00:18:37 gate8 last message repeated 2 times
> Aug 31 00:18:38 gate8 kernel: ifa_del_loopback_route: deletion failed
> Aug 31 00:18:38 gate8 kernel: if_rtdel: error 3
> Aug 31 00:18:38 gate8 last message repeated 2 times
> 
> What do they mean and how can I find the cause of it ?  [...]

src/sys/net/if.c
1371                 err = rtrequest_fib(RTM_DELETE, rt_key(rt), rt->rt_gateway,
1372                                 rt_mask(rt), rt->rt_flags|RTF_RNH_LOCKED,
1373                                 (struct rtentry **) NULL, rt->rt_fibnum);
1374                 if (err) {
1375                         log(LOG_WARNING, "if_rtdel: error %d\n", err);
1376                 }

Now looking for return() values in rtrequest_fib():

src/sys/net/route.c
 745 int
 746 rtrequest_fib(int req,
 ...
 756         if (dst->sa_len == 0)
 757                 return(EINVAL);
 ...
 764         return rtrequest1_fib(req, &info, ret_nrt, fibnum);
 765 }

And on to rtrequest1_fib, which has a ton of error conditions which can
be returned (some natively, some from other functions like
rn_mpath_update(), plus a fun macro in use (senderr)).  A lot of this
code is #ifdef'd too, based on routing features (FLOWTABLE, RADIX_MPATH)
that are defined.

Direct values that rtrequest1_fib() returns in whatever circumstance:

n/a          =  0 = no error
EAFNOSUPPORT = 47 = Address family not supported by protocol family
EINVAL       = 22 = Invalid argument
ESRCH        =  3 = No such process
ENOBUFS      = 55 = No buffer space available
EEXIST       = 17 = File exists
EOPNOTSUPP   = 45 = Operation not supported

Functions that rtrequest1_fib() calls whose error codes are passed
directly via return() or senderr:

rn_mpath_update() = can return 0 (success) or ESRCH
rt_getifa_fib()   = can return 0 (success) or 51 (ENETUNREACH)
rt_setgate()      = can return 0 (success) or ENOBUFS

So in summary, your error 47 would be the result of code inside of
rtrequest1_fib() itself (someone will need to look at that), while your
error 3 could be caused by rtequest1_fib() or rn_mpath_update().

I have no familiarity with this code, so someone familiar with the
networking layer will have to help.  freebsd-net or freebsd-hackers
might be worthwhile.

Possibly your machine acts as a forwarding gateway and isn't able to
properly route/forward/process certain kinds of packets?

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |