Re: Unable to decode message length

Thank you for the help. But here I get exactly the same data as you. So I suppose the issue is on the server side only. I will try with gdb now. On Wed, Jul 15, 2020 at 16:02, Michal Privoznik <mprivozn(a)redhat.com&gt; wrote: > On 7/14/20 7:42 PM, Valentin David wrote: >> Hello all, >> >> I have been trying to get libvirtd to work but when I connect to it >> with virsh, I get "error : virNetMessageDecodeLength:131 : Unable >> to decode message length" >> >> This happens with libvirt 6.1.0, libtirpc 1.2.6, rpcsvc-proto >> 1.4.1. I have tried with other versions, but I still get the same >> error. >> >> If anybody has any tip on what to try next, that would be helpful. >> Thank you in advance. >> >> Here is the debug log of libvirtd when I try to connect with virsh: >> > >> 2020-07-14 16:29:58.220+0000: 5352: error : >> virNetMessageDecodeLength:131 : Unable to decode message length > > This is interesting. The error message is reported when xdr_u_int() > fails. It is trying to decode first 4 bytes of incoming message to > see how long it is. I can think of two possible reasons for this: > > 1) the client did not send 4 bytes > 2) the rpcgen generated some wrong code that libtirpc is unable to > decode. > > I suggest using wireshark to check what data is send (don't forget > to use plain TCP transport in URI, for instance 'virsh -c > qemu+tcp://localhost/system'). The first call that virsh does is > AUTH_LIST procedure and it should look like this: > > 0000 00 00 00 00 00 00 00 00 00 00 00 00 86 dd 60 04 > 0010 52 cc 00 3c 06 40 00 00 00 00 00 00 00 00 00 00 > 0020 00 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 > 0030 00 00 00 00 00 01 df 6c 40 7d fd e7 38 94 09 92 > 0040 bf 48 80 18 02 00 00 44 00 00 01 01 08 0a c9 4f > 0050 f4 f2 c9 4f f4 f2 00 00 00 1c 20 00 80 86 00 00 > 0060 00 01 00 00 00 42 00 00 00 00 00 00 00 00 00 00 > 0070 00 00 > > bytes 0x56-0x59 contain 0x1c (= 28) which is the length of the > packet (28 bytes). This is how our dissector decodes it: > > Libvirt > length: 28 > program: REMOTE (0x20008086) > version: 1 > procedure: AUTH_LIST (66) > type: CALL (0) > serial: 0 > status: OK (0) > > > Michal > >