From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44383) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cW51B-0000CG-SQ for qemu-devel@nongnu.org; Tue, 24 Jan 2017 12:36:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cW518-0006wo-38 for qemu-devel@nongnu.org; Tue, 24 Jan 2017 12:36:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41246) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cW517-0006w5-Oi for qemu-devel@nongnu.org; Tue, 24 Jan 2017 12:36:26 -0500 Date: Tue, 24 Jan 2017 17:36:19 +0000 From: "Daniel P. Berrange" Message-ID: <20170124173619.GB28745@redhat.com> Reply-To: "Daniel P. Berrange" References: <1485272673-5877-1-git-send-email-zdai@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1485272673-5877-1-git-send-email-zdai@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 1/1] Migration: libvirt live migration over RDMA of ipv6 addr failed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Dai Cc: qemu-devel@nongnu.org, amit.shah@redhat.com, zdai@us.ibm.com, mdroth@linux.vnet.ibm.com, quintela@redhat.com On Tue, Jan 24, 2017 at 09:44:33AM -0600, David Dai wrote: > Using libvirt to do live migration over RDMA via ip v6 address failed. > For example: > # virsh migrate --live --migrateuri rdma://[deba::2222]:49152 \ > rhel73_host1_guest1 qemu+ssh://[deba::2222]/system --verbose > root@deba::2222's password: > error: internal error: unable to execute QEMU command 'migrate': RDMA ERROR: > could not rdma_getaddrinfo address deba > > As we can see, the ip v6 address used by rdma_getaddrinfo() has only "deba" > part. It should be "deba::2222". > > 1) According to rfc 3986, a literal ip v6 address should be enclosed > in '[' and ']'. > When using virsh command to do live migration via ip v6 addresss, user > will input the ip v6 address with brackets (i.e. rdma://[deba::2222]:49152). > libvirt will parse command line option by calling virURIParse(). > Inside it calls virStringStripIPv6Brackets() to strip off the brackets. > The uri passed in to virURIParse() is: > "uri = rdma://[deba::2222]:49152" > Inside virURIParse() routine, it will strip off the bracket '[' and ']' if > it's ip v6 address. Then save the ip v6 address in this format "deba::2222" > in the virURI->server field, and to be passed to qemu. > > 2) At the beginning of migration, in qemu's qemu_rdma_data_init(host_port) > routine, it calls inet_parse(host_port) routine to parse the ip v6 address and > port string obtained from libvirt. > The input string host_port passed to qemu_rdma_data_init() can be: > "hostname:port", or > "ipv4address:port", or > "[ipv6address]:port" (i.e "[deba::2222]:49152"), or > "ipv6address:port" (i.e "deba::2222:49152"). > Existing qemu api inet_parse() can handle the above first 3 cases properly, > but didn't handle the last case ("ipv6address:port") correctly. > In this live migration over rdma via ip v6 address case, the server ip v6 > address obtained from libvirt doesn't contain the brackets '[' and ']' > (i.e. "deba::2222:49152"). It caused inet_parse() to parse only "deba" part, > and stopped at the 1st colon ':'. As the result, the subsequent > rdma_getaddrinfo() with ip address "deba" will fail. > > If we don't strip off brackets '[' and ']' for an ip v6 address in libvirt's > virURIParse(), it will cause libvirt ipv6 ssh authentication failure. > > NOTE: > If using libvirt to do live migration over TCP via ip v6 address: > # virsh migrate --live --migrateuri tcp://[deba::2222]:49152 \ > rhel73_host1_guest1 qemu+ssh://[deba::2222]/system --verbose > It works fine. > In migrateuri of tcp case, libvirt will call virNetSocketNewConnectTCP() > directly to connect to remote "deba::2222:49152" after it strips off > the bracket '[' and ']' for an ip v6 address. > On qemu side, fd_start_outgoing_migration() will be called to do migration. > It doesn't call inet_parse(). So we don't see issue in tcp case. > > Solution: > I choose to fix the code in qemu's inet_parse() routine to parse the > ip v6 addresss w/o brackets properly (i.e. "deba::2222:49152" format). That is not right - "deba::222:49152" is *not* a valid address. It is mandatory to use [] when providing a numeric IPv6 address. So there's nothing broken in QEMU here - libvirt needs fixing to pass correct data to QEMU Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|