Re: [Qemu-devel] [PATCH 3/4] net: split hostname and service by last colon

[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).