[Olsr-dev] [PATCH v1 1/2] android: fix type punning warnings on IN6_IS_ADDR_V4MAPPED

[Hans-Christoph Steiner]

If that works, it is OK by me.  My inclination would still be to change the
definition of v6 in a #ifdef __ANDROID__ and make it match the Android
definition.  Just seems cleaner to me.

.hc

On 10/23/2012 10:11 AM, Ferry Huberts wrote:
> How about this then:
> 
>> diff --git a/src/ipcalc.h b/src/ipcalc.h
>> index 30b8068..f6836d4 100644
>> --- a/src/ipcalc.h
>> +++ b/src/ipcalc.h
>> @@ -161,9 +161,19 @@ sockaddr4_to_string(struct ipaddr_str *const buf, const
>> struct sockaddr *const a
>>    return ip4_to_string(buf, addr4->sin_addr);
>>  }
>>
>> +
>>  static INLINE bool
>>  is_prefix_niit_ipv6(const struct olsr_ip_prefix *p) {
>> -  return olsr_cnf->ip_version == AF_INET6 &&
>> IN6_IS_ADDR_V4MAPPED(&p->prefix.v6)
>> +#ifdef __ANDROID__
>> +  #define IN6_IS_ADDR_V4MAPPED_ANDROID_WORKAROUND(a) \
>> +    ((((__const uint32_t *) (a))[0] == 0)                      \
>> +     && (((__const uint32_t *) (a))[1] == 0)                  \
>> +     && (((__const uint32_t *) (a))[2] == htonl (0xffff)))
>> +    bool v4mapped = IN6_IS_ADDR_V4MAPPED_ANDROID_WORKAROUND(&p->prefix.v6);
>> +#else
>> +    bool v4mapped = IN6_IS_ADDR_V4MAPPED(&p->prefix.v6);
>> +#endif
>> +  return olsr_cnf->ip_version == AF_INET6 && v4mapped
>>        && p->prefix_len >= ipv6_mappedv4_route.prefix_len;
>>  }
> 
> 
> 
> 
> 
> On 22-10-12 20:01, Hans-Christoph Steiner wrote:
>>
>>
>> On 10/22/2012 01:44 PM, Henning Rogge wrote:
>>> On Mon, Oct 22, 2012 at 7:37 PM, Hans-Christoph Steiner
>>> <(spam-protected)> wrote:
>>>> On 10/22/2012 12:50 PM, Henning Rogge wrote:
>>>>> I must admit I still have trouble why the compiler has trouble with
>>>>> the old statement. The new one is a crazy thing, some special GCC
>>>>> extension.
>>>>>
>>>>> If we replace it, I would suggest building an inline function that
>>>>> takes the "olsr_ip_addr" union and gives back a boolean. Much better
>>>>> than trying to fix a crazy preprocessor command.
>>>>
>>>> Did you look at the Android header snippet I posted in this thread?  Once you
>>>> do, its clear why the compiler is throwing that warning.  The Android header
>>>> declares things differently and the GNU header.  The current olsrd code
>>>> follows the GNU definition.
>>>
>>> What would you two think about this patch? That sidesteps the whole
>>> problem quite easily.
>>>
>>> diff --git a/src/ipcalc.h b/src/ipcalc.h
>>> index 30b8068..aeb77b7 100644
>>> --- a/src/ipcalc.h
>>> +++ b/src/ipcalc.h
>>> @@ -163,7 +163,8 @@ sockaddr4_to_string(struct ipaddr_str *const buf,
>>> const struct sockaddr *const a
>>>
>>>   static INLINE bool
>>>   is_prefix_niit_ipv6(const struct olsr_ip_prefix *p) {
>>> -  return olsr_cnf->ip_version == AF_INET6 &&
>>> IN6_IS_ADDR_V4MAPPED(&p->prefix.v6)
>>> +  return olsr_cnf->ip_version == AF_INET6
>>> +      && memcmp(p, &ipv6_mappedv4_route.prefix,
>>> ipv6_mappedv4_route.prefix_len/8) == 0
>>>         && p->prefix_len >= ipv6_mappedv4_route.prefix_len;
>>>   }
>>
>> If that is only to avoid using an #ifdef __ANDROID__, then I think its harder
>> to read since its removing the clearly named IN6_IS_ADDR_V4MAPPED and
>> replacing it with some mem tricks.  At the very least it should be well
>> commented.
>>
>> .hc
>>
>