Stephen Hemminger wrote:
> On Mon, 18 Dec 2017 23:37:09 +0200
> Serhey Popovich <serhe.popov...@gmail.com> wrote:
>
>> Stephen Hemminger wrote:
>>> On Mon, 18 Dec 2017 23:02:07 +0200
>>> Serhey Popovich <serhe.popov...@gmail.com> wrote:
>>>
>>>> Stephen Hemminger wrote:
>>>>> On Mon, 18 Dec 2017 20:54:06 +0200
>>>>> Serhey Popovych <serhe.popov...@gmail.com> wrote:
>>>>>
>>>>>> diff --git a/ip/iplink.c b/ip/iplink.c
>>>>>> index 1e685cc..4f9c169 100644
>>>>>> --- a/ip/iplink.c
>>>>>> +++ b/ip/iplink.c
>>>>>> @@ -586,8 +586,10 @@ int iplink_parse(int argc, char **argv, struct
>>>>>> iplink_req *req,
>>>>>> *name = *argv;
>>>>>> } else if (strcmp(*argv, "index") == 0) {
>>>>>> NEXT_ARG();
>>>>>> + if (*index)
>>>>>> + duparg("index", *argv);
>>>>>> *index = atoi(*argv);
>>>>>> - if (*index < 0)
>>>>>> + if (*index <= 0)
>>>>>
>>>>> Why not use strtoul instead of atoi?
>>>> Do not see reason for strtoul() instead atoi():
>>>>
>>>> 1) main arg: indexes in kernel represented as "int", which is
>>>> signed. <= 0 values are reserved for various special purposes
>>>> (see net/core/fib_rules.c on how device matching implemented).
>>>>
>>>> Configuring network device manually with index <= 0 is not correct
>>>> (however possible). Kernel itself never chooses ifindex <= 0.
>>>>
>>>> Having unsigned int > 0x7fffffff actually means index <= 0.
>>>>
>>>> 2) this is not single place in iproute2 where it is used: not
>>>> going to remove last user.
>>>>
>>>> 3) make changes clear and transparent for review.
>>>
>>> I would rather all of iproute2 correctly handles unsigned values.
>>> Too much code is old K&R style C "the world is an int" and "who needs
>>> to check for negative".
>>
>> You are right :(. I'm just trying to improve things a bit.
>>
>>>
>>> There already is get_unsigned() in iproute2 util functions.
>> This is good one based on strtoul(). But do we want to submit say
>> index = (unsigned int)2147483648(0x7fffffff) to the kernel that is
>> illegal from it's perspective?
>>
>> Or do you mean I can prepare treewide change to replace atoi() with
>> get_unsigned()/get_integer() where appropriate?
>>
>> We already check if (*index < 0) since commit 3c682146aeff
>> (iplink: forbid negative ifindex and modifying ifindex), and I just
>> put index == 0 in the same range of invalid indexes.
>>
>
> The legacy BSD ABI for interfaces uses int, so that sets the upper
> bound for kernel.
>
> The netlink ABI limit is u32 for ifindex so technically 1..UINT32_MAX are
> possible values but kernel is bound by BSD mistake.
Thank you for in depth explanation!> > I will take the original patch. > >
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