From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Wolf Subject: Re: [Qemu-devel] [PATCH 3/4] net: split hostname and service by last colon Date: Mon, 05 Mar 2012 09:57:59 +0100 Message-ID: <4F548017.1060705@redhat.com> References: <20120210062608.13397.43361.stgit@dhcp-8-167.nay.redhat.com> <20120210062719.13397.9953.stgit@dhcp-8-167.nay.redhat.com> <4F475874.8050803@redhat.com> <4F5040BE.2000807@redhat.com> <4F5099BC.5050009@redhat.com> <4F50A282.7060401@redhat.com> <4F512590.2080407@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Amos Kong , aliguori@us.ibm.com, kvm@vger.kernel.org, quintela@redhat.com, jasowang@redhat.com, qemu-devel@nongnu.org To: Laine Stump Return-path: Received: from mx1.redhat.com ([209.132.183.28]:25567 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751093Ab2CEIyd (ORCPT ); Mon, 5 Mar 2012 03:54:33 -0500 In-Reply-To: <4F512590.2080407@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Am 02.03.2012 20:54, schrieb Laine Stump: > On 03/02/2012 05:35 AM, Kevin Wolf wrote: >> Am 02.03.2012 10:58, schrieb Amos Kong: >>> On 02/03/12 11:38, Amos Kong wrote: >>>>>> --- a/net.c >>>>>> +++ b/net.c >>>>>> @@ -84,7 +84,7 @@ static int get_str_sep(char *buf, int buf_size, >>>>>> const char **pp, int sep) >>>>>> const char *p, *p1; >>>>>> int len; >>>>>> p = *pp; >>>>>> - p1 = strchr(p, sep); >>>>>> + p1 = strrchr(p, sep); >>>>>> if (!p1) >>>>>> return -1; >>>>>> len = p1 - p; >>>>> And what if the port isn't specified? I think you would erroneously >>>>> interpret the last part of the IP address as port. >>> Hi Kevin, port must be specified in '-incoming' parameters and migrate >>> monitor cmd. >>> >>> qemu-kvm ... -incoming tcp:$host:$port >>> (qemu) migrate -d tcp:$host:$port >>> >>> >>> If use boot up guest by wrong cmdline, qemu will report an error msg. >>> >>> # ./x86_64-softmmu/qemu-system-x86_64 --enable-kvm -boot n -incoming >>> tcp:2312::8272 -monitor stdio >>> qemu-system-x86_64: qemu: getaddrinfo: Name or service not known >>> tcp_server_start: Invalid argument >>> Migration failed. Exit code tcp:2312::8272(-22), exiting. >> Which is because 2312: isn't a valid IP address, right? But what if you >> have something like 2312::1234:8272? If you misinterpret the 8272 as a >> port number, the remaining address is still a valid IPv6 address. > > This is made irrelevant by PATCH 4/4, which allows for the IP address to > be placed inside brackets: > > [2312::8272]:port > > (at least it's irrelevant if your documentation *requires* brackets for > all numeric ipv6-address:port pairs, which is strongly recommended by > RFC 5952). It really is impossible to disambiguate the meaning of the > final ":nnnn" unless you require these brackets (or 1) require full > specification of all potential colons in the IPv6 address or require > that the port *always* be specified, neither of which seem acceptable to > me). Here you're actually explaining why it's not irrelevant. You don't want to enforce port numbers, so 2312::1234:8272 must be interpreted as an IPv6 address without a port. This code however would take 8727 as the port and 2312::1234 as the IPv6 address, which is not what you expected (even after brackets are allowed - they don't make a difference because the example doesn't use brackets). Kevin