> On Jun 28, 2018, at 10:17 AM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote:
>
> On Thu, 2018-06-28 at 09:45 -0400, Chuck Lever wrote:
>> We have a report that some commercial NFS file servers still do not
>> support rpcbind v4 correctly. They return RPC_CANTDECODEARGS instead
>> of RPC_PROGVERSMISMATCH, so our rpcbind client now errors out
>> immediately instead of trying a lower rpcbind version.
>>
>> To address this, convert the "if () else if () else if ()" to a
>> switch statement to make it straightforward to add new status codes
>> to the error processing logic. Then, add a case for
>> RPC_CANTDECODEARGS.
>>
>> Reported-by: Yuan-Yao Sung <yysung@xxxxxxxxxxxxxx>
>> Fixes: 5e7b57bc20bd ("rpcinfo: change order of version to be ... ")
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> Tested-by: Yuan-Yao Sung <yysung@xxxxxxxxxxxxxx>
>> ---
>> src/rpcb_clnt.c | 13 +++++++++----
>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/rpcb_clnt.c b/src/rpcb_clnt.c
>> index 4b44364..d6fefd0 100644
>> --- a/src/rpcb_clnt.c
>> +++ b/src/rpcb_clnt.c
>> @@ -846,6 +846,7 @@ __rpcb_findaddr_timed(program, version, nconf,
>> host, clpp, tp)
>> struct netbuf *address = NULL;
>> rpcvers_t start_vers = RPCBVERS4;
>> struct netbuf servaddr;
>> + struct rpc_err rpcerr;
>>
>> /* parameter checking */
>> if (nconf == NULL) {
>> @@ -902,7 +903,8 @@ __rpcb_findaddr_timed(program, version, nconf,
>> host, clpp, tp)
>> clnt_st = CLNT_CALL(client,
>> (rpcproc_t)RPCBPROC_GETADDR,
>> (xdrproc_t) xdr_rpcb, (char *)(void *)&parms,
>> (xdrproc_t) xdr_wrapstring, (char *)(void *)
>> &ua, *tp);
>> - if (clnt_st == RPC_SUCCESS) {
>> + switch (clnt_st) {
>> + case RPC_SUCCESS:
>> if ((ua == NULL) || (ua[0] == 0)) {
>> /* address unknown */
>> rpc_createerr.cf_stat =
>> RPC_PROGNOTREGISTERED;
>> @@ -924,12 +926,15 @@ __rpcb_findaddr_timed(program, version, nconf,
>> host, clpp, tp)
>> (char *)(void *)&servaddr);
>> __rpc_fixup_addr(address, &servaddr);
>> goto done;
>> - } else if (clnt_st == RPC_PROGVERSMISMATCH) {
>> - struct rpc_err rpcerr;
>> + case RPC_PROGVERSMISMATCH:
>> clnt_geterr(client, &rpcerr);
>> if (rpcerr.re_vers.low > RPCBVERS4)
>> goto error; /* a new version, can't
>> handle */
>> - } else if (clnt_st != RPC_PROGUNAVAIL) {
>> + /* Try the next lower version */
>> + case RPC_PROGUNAVAIL:
>> + case RPC_CANTDECODEARGS:
>> + break;
>> + default:
>> /* Cant handle this error */
>> rpc_createerr.cf_stat = clnt_st;
>> clnt_geterr(client,
>> &rpc_createerr.cf_error);
>>
>> --
>
> Interesting... Do these servers return any other non-sanctioned errors?
It's a NetApp filer. GARBAGE_ARGS is what goes on the wire.
> I can't find RPC_CANTDECODEARGS described in any of the official RFCs
> pertaining to RPC, NFS or the RPCBIND protocol. It appears to be listed
> among the private error codes in the libtirpc header files, and in some
> java libraries, but googling around appeared to indicate that those
> codes are intended for internal library signaling only, and should not
> appear on the wire:
>
> https://people.eecs.berkeley.edu/~jonah/javadoc/org/acplt/oncrpc/OncRp
> cException.html
RPC_CANTDECODEARGS is part of the public RPC API, it doesn't go on
the wire.
I will fix the patch description and resend.
--
Chuck Lever
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