From patchwork Fri Jul 1 14:44:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Bergantinos Corpas X-Patchwork-Id: 12903471 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E90AC433EF for ; Fri, 1 Jul 2022 14:44:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230308AbiGAOo2 (ORCPT ); Fri, 1 Jul 2022 10:44:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229998AbiGAOo1 (ORCPT ); Fri, 1 Jul 2022 10:44:27 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 27DDA13DF7 for ; Fri, 1 Jul 2022 07:44:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656686666; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=h7SXxbvBdKgkV0Y07gNFvEYBimc5aPt6PlyHKYYqNKE=; b=L99i9ib6qbIInZ8t2BL0rcP6f6CUBtuyiB/7+MxhUuPxYowtv/+TswWNFBiJpL+DXbCUL8 u1QTikhm5znsRyQnlpb2VV4nkxRDSXQHAgal2joHq2eg8agreVBbqkAmQrfxZ/01+4do9J 6SRCpyBp2Z5d3NpnfkXurdqWE0MSZpY= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-191-8kHir0_gM0-_eL972fWiRQ-1; Fri, 01 Jul 2022 10:44:25 -0400 X-MC-Unique: 8kHir0_gM0-_eL972fWiRQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CF1581019C86; Fri, 1 Jul 2022 14:44:24 +0000 (UTC) Received: from idlethread.redhat.com (unknown [10.40.194.217]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11C8040336E; Fri, 1 Jul 2022 14:44:23 +0000 (UTC) From: Roberto Bergantinos Corpas To: libtirpc-devel@lists.sourceforge.net Cc: linux-nfs@vger.kernel.org Subject: [PATCH] rpcb_clnt.c add mechanism to try v2 protocol first Date: Fri, 1 Jul 2022 16:44:22 +0200 Message-Id: <20220701144422.328923-1-rbergant@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org There have been previous attempts to revert protocol tryout algorithm from v4,v3,v2 to previous v2,v4,v3 : https://www.spinics.net/lists/linux-nfs/msg89228.html Apart from GETADDR/NAT issue originating that proposed change, its possible that some legacy custom applications still use v2 of protocol with libtirpc. The change proposed here, introduces an environment variable "RPCB_V2FIRST" so that, if defined, old behaviour is used. This is more flexible and allow us to selectively pick what application reverts to old behaviour instead of a system-wide change. Example : $ tcpdump -s0 -i ens3 port 111 -w /tmp/capture.pcap &> /dev/null & [1] 13016 $ rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null $ RPCB_V2FIRST=1 rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null $ pkill tcpdump $ tshark -tad -nr /tmp/capture.pcap -Y portmap -T fields -e _ws.col.Info V4 GETADDR Call V4 GETADDR Reply (Call In 4) V2 GETPORT Call MOUNT(100005) V:0 TCP V2 GETPORT Reply (Call In 14) Port:20048 Signed-off-by: Roberto Bergantinos Corpas --- man/rpcbind.3t | 2 ++ src/rpcb_clnt.c | 27 ++++++++++++++++++++++++--- tirpc/rpc/pmap_prot.h | 2 ++ 3 files changed, 28 insertions(+), 3 deletions(-) diff --git a/man/rpcbind.3t b/man/rpcbind.3t index ec492cc..4cb271b 100644 --- a/man/rpcbind.3t +++ b/man/rpcbind.3t @@ -187,6 +187,8 @@ in .El .Sh AVAILABILITY These functions are part of libtirpc. +.Sh ENVIRONMENT +If RPCB_V2FIRST is defined, rpcbind protocol version tryout algorithm changes from v4,v2,v3 to v2,v4,v3. .Sh SEE ALSO .Xr rpc_clnt_calls 3 , .Xr rpc_svc_calls 3 , diff --git a/src/rpcb_clnt.c b/src/rpcb_clnt.c index 0c34cb7..db3799e 100644 --- a/src/rpcb_clnt.c +++ b/src/rpcb_clnt.c @@ -818,7 +818,8 @@ error: * The algorithm used: If the transports is TCP or UDP, it first tries * version 4 (srv4), then 3 and then fall back to version 2 (portmap). * With this algorithm, we get performance as well as a plan for - * obsoleting version 2. + * obsoleting version 2. This behaviour is reverted to old algorithm + * if RPCB_V2FIRST environment var is defined * * For all other transports, the algorithm remains as 4 and then 3. * @@ -839,6 +840,10 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) #ifdef NOTUSED static bool_t check_rpcbind = TRUE; #endif + +#ifdef PORTMAP + static bool_t portmap_first = FALSE; +#endif CLIENT *client = NULL; RPCB parms; enum clnt_stat clnt_st; @@ -895,8 +900,18 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) parms.r_addr = (char *) &nullstring[0]; } - /* First try from start_vers(4) and then version 3 (RPCBVERS) */ + /* First try from start_vers(4) and then version 3 (RPCBVERS), except + * if env. var RPCB_V2FIRST is defined */ + +#ifdef PORTMAP + if (getenv(V2FIRST)) { + portmap_first = TRUE; + LIBTIRPC_DEBUG(3, ("__rpcb_findaddr_timed: trying v2-port first\n")); + goto portmap; + } +#endif +rpcbind: CLNT_CONTROL(client, CLSET_RETRY_TIMEOUT, (char *) &rpcbrmttime); for (vers = start_vers; vers >= RPCBVERS; vers--) { /* Set the version */ @@ -944,10 +959,16 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) } #ifdef PORTMAP /* Try version 2 for TCP or UDP */ + if (portmap_first) + goto error; /* we tried all versions if reached here */ +portmap: if (strcmp(nconf->nc_protofmly, NC_INET) == 0) { address = __try_protocol_version_2(program, version, nconf, host, tp); if (address == NULL) - goto error; + if (portmap_first) + goto rpcbind; + else + goto error; } #endif /* PORTMAP */ diff --git a/tirpc/rpc/pmap_prot.h b/tirpc/rpc/pmap_prot.h index 75354ce..7718b8b 100644 --- a/tirpc/rpc/pmap_prot.h +++ b/tirpc/rpc/pmap_prot.h @@ -84,6 +84,8 @@ #define PMAPPROC_DUMP ((u_long)4) #define PMAPPROC_CALLIT ((u_long)5) +#define V2FIRST "RPCB_V2FIRST" + struct pmap { long unsigned pm_prog; long unsigned pm_vers;