> On Feb 7, 2018, at 4:16 PM, NeilBrown <neilb@xxxxxxxx> wrote: > > On Wed, Feb 07 2018, Chuck Lever wrote: > >>> On Feb 6, 2018, at 11:35 PM, NeilBrown <neilb@xxxxxxxx> wrote: >>> >>> On Mon, Feb 05 2018, Tom Talpey wrote: >>> >>>> On 2/5/2018 12:02 PM, Chuck Lever wrote: >>>>> Heya Steve- >>>>> >>>>>> On Feb 5, 2018, at 11:36 AM, Steve Dickson <steved@xxxxxxxxxx> wrote: >>>>>> >>>>>> Over the weekend I did some experimenting with >>>>>> the remote call code in rpcbind. The code does >>>>>> functionally work but is very antiquated when >>>>>> it comes to the latest NFS versions. >>>>>> >>>>>> Since only UDP sockets are used to do remote calls >>>>>> using the documented interfaces pmap_rmtcall() and callrpc() >>>>>> calls to NFS will fail (actual times out) since UDP is no >>>>>> longer supported. >>>>>> >>>>>> The undocumented interface rpc_call() can be used to >>>>>> call into NFS since the protocol can specified, which >>>>>> also means the PMAPPROC_CALLIT protocol is not used. >>>>>> >>>>>> It turns out privilege port are not needed to make >>>>>> remote calls, at least with my testing. >>>>> >>>>> It's not quite clear what you are claiming here, but >>>>> I'm guessing that what you demonstrated is that the >>>>> CALLIT _listener_ does not have to be privileged? >>> >>> rpcbind listens for CALLIT on port 111. >> >> Right, my bad. CALLIT is an RPC procedure, not an RPC >> program. >> >> >>> Listening on some other port wouldn't ever get the messges... >> >> Then we still do not understand why rpcbind is opening >> and registering a second listener port. I can't think of >> any reason it should do this other than that there is a >> bug. > > This is a port on which it forwards CALLIT messages and listens for > replies, which it then sends back to the originator. In order to be > able to handle CALLIT asynchronously with other requests, it needs to > register the port with the internal listening framework. Sorry, this is still not making sense to me. Can you create a ladder diagram that shows the exchange of Call and Reply messages? > For comparison, portmap handles CALLIT asynchronously by forking. > > Thanks, > NeilBrown -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
