[IPV6]: ROUTE:read ifname in rt6_info_route()

[IPV6]: ROUTE:read ifname in rt6_info_route()

[Yuta sugiura]

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Hi,
I have a suggestion about /proc/net/IPv6_route format.
In rt6_info_route(),  interface name is treated as a maximum 8 characters.
But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ= 16]
so, I think that it should change "%8s" to "%16s".

Thanks,



[-- Attachment #2: ipv6_route_ifnamesiz.patch --]
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diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1394ddb..9ad58e7 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2434,7 +2434,7 @@ static int ip6_route_dev_notify(struct notifier_block *this,
 
 #ifdef CONFIG_PROC_FS
 
-#define RT6_INFO_LEN (32 + 4 + 32 + 4 + 32 + 40 + 5 + 1)
+#define RT6_INFO_LEN (32 + 4 + 32 + 4 + 32 + 48 + 5 + 1)
 
 struct rt6_proc_arg
 {
@@ -2462,7 +2462,7 @@ static int rt6_info_route(struct rt6_info *rt, void *p_arg)
 	} else {
 		seq_puts(m, "00000000000000000000000000000000");
 	}
-	seq_printf(m, " %08x %08x %08x %08x %8s\n",
+	seq_printf(m, " %08x %08x %08x %08x %16s\n",
 		   rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
 		   rt->u.dst.__use, rt->rt6i_flags,
 		   rt->rt6i_dev ? rt->rt6i_dev->name : "");

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[David Miller]

From: Yuta sugiura <ysugiura@miraclelinux.com>
Date: Thu, 16 Apr 2009 20:05:05 +0900

> Hi,
> I have a suggestion about /proc/net/IPv6_route format.
> In rt6_info_route(), interface name is treated as a maximum 8
> characters.
> But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
> 16]
> so, I think that it should change "%8s" to "%16s".

Isn't there a way to pass the field length as a paramenter
to formatting functions?  Then we can just pass in
IFNAMESIZE as that parameter.

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Stephen Hemminger]

On Thu, 16 Apr 2009 04:38:00 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:

> From: Yuta sugiura <ysugiura@miraclelinux.com>
> Date: Thu, 16 Apr 2009 20:05:05 +0900
> 
> > Hi,
> > I have a suggestion about /proc/net/IPv6_route format.
> > In rt6_info_route(), interface name is treated as a maximum 8
> > characters.
> > But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
> > 16]
> > so, I think that it should change "%8s" to "%16s".
> 
> Isn't there a way to pass the field length as a paramenter
> to formatting functions?  Then we can just pass in
> IFNAMESIZE as that parameter.

	seq_printf(m, " %08x %08x %08x %08x %*s\n"
                   rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
 		   rt->u.dst.__use, rt->rt6i_flags,
                   IFNAMESIZE, 
 		   rt->rt6i_dev ? rt->rt6i_dev->name : "")

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Brian Haley]

Stephen Hemminger wrote:
> On Thu, 16 Apr 2009 04:38:00 -0700 (PDT)
> David Miller <davem@davemloft.net> wrote:
> 
>> From: Yuta sugiura <ysugiura@miraclelinux.com>
>> Date: Thu, 16 Apr 2009 20:05:05 +0900
>>
>>> Hi,
>>> I have a suggestion about /proc/net/IPv6_route format.
>>> In rt6_info_route(), interface name is treated as a maximum 8
>>> characters.
>>> But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
>>> 16]
>>> so, I think that it should change "%8s" to "%16s".
>> Isn't there a way to pass the field length as a paramenter
>> to formatting functions?  Then we can just pass in
>> IFNAMESIZE as that parameter.
> 
> 	seq_printf(m, " %08x %08x %08x %08x %*s\n"
>                    rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
>  		   rt->u.dst.__use, rt->rt6i_flags,
>                    IFNAMESIZE, 
>  		   rt->rt6i_dev ? rt->rt6i_dev->name : "")

Does the kernel actually truncate an interface name more than 8 chars long in
the original version?  I did a quick test in userspace and found that

	printf("%*s\n", 1, "foo");

prints:

foo

I think the width specifier is used for *minimum* width, not maximum.

-Brian

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Andreas Schwab]

Stephen Hemminger <shemminger@vyatta.com> writes:

> On Thu, 16 Apr 2009 04:38:00 -0700 (PDT)
> David Miller <davem@davemloft.net> wrote:
>
>> From: Yuta sugiura <ysugiura@miraclelinux.com>
>> Date: Thu, 16 Apr 2009 20:05:05 +0900
>> 
>> > Hi,
>> > I have a suggestion about /proc/net/IPv6_route format.
>> > In rt6_info_route(), interface name is treated as a maximum 8
>> > characters.
>> > But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
>> > 16]
>> > so, I think that it should change "%8s" to "%16s".
>> 
>> Isn't there a way to pass the field length as a paramenter
>> to formatting functions?  Then we can just pass in
>> IFNAMESIZE as that parameter.
>
> 	seq_printf(m, " %08x %08x %08x %08x %*s\n"
>                    rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
>  		   rt->u.dst.__use, rt->rt6i_flags,
>                    IFNAMESIZE, 
>  		   rt->rt6i_dev ? rt->rt6i_dev->name : "")

Actually since it is the last item on the line a field width does not
make much sense, and omitting it would print the name left justified.

(And RT6_INFO_LEN is not used any more.)

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Stephen Hemminger]

On Thu, 16 Apr 2009 18:47:04 +0200
Andreas Schwab <schwab@linux-m68k.org> wrote:

> Stephen Hemminger <shemminger@vyatta.com> writes:
> 
> > On Thu, 16 Apr 2009 04:38:00 -0700 (PDT)
> > David Miller <davem@davemloft.net> wrote:
> >
> >> From: Yuta sugiura <ysugiura@miraclelinux.com>
> >> Date: Thu, 16 Apr 2009 20:05:05 +0900
> >> 
> >> > Hi,
> >> > I have a suggestion about /proc/net/IPv6_route format.
> >> > In rt6_info_route(), interface name is treated as a maximum 8
> >> > characters.
> >> > But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
> >> > 16]
> >> > so, I think that it should change "%8s" to "%16s".
> >> 
> >> Isn't there a way to pass the field length as a paramenter
> >> to formatting functions?  Then we can just pass in
> >> IFNAMESIZE as that parameter.
> >
> > 	seq_printf(m, " %08x %08x %08x %08x %*s\n"
> >                    rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
> >  		   rt->u.dst.__use, rt->rt6i_flags,
> >                    IFNAMESIZE, 
> >  		   rt->rt6i_dev ? rt->rt6i_dev->name : "")
> 
> Actually since it is the last item on the line a field width does not
> make much sense, and omitting it would print the name left justified.
> 
> (And RT6_INFO_LEN is not used any more.)
> 
> Andreas.
> 

The issue is what happens if name is not null terminated. in this case
I bet the kernel already handles that.

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Yuta sugiura]

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Thank you for respons to my e-mail.
I read net-snmp's patch as reference.
How about this method?

Stephen Hemminger wrote:
> On Thu, 16 Apr 2009 18:47:04 +0200
> Andreas Schwab <schwab@linux-m68k.org> wrote:
>
>   
>> Stephen Hemminger <shemminger@vyatta.com> writes:
>>
>>     
>>> On Thu, 16 Apr 2009 04:38:00 -0700 (PDT)
>>> David Miller <davem@davemloft.net> wrote:
>>>
>>>       
>>>> From: Yuta sugiura <ysugiura@miraclelinux.com>
>>>> Date: Thu, 16 Apr 2009 20:05:05 +0900
>>>>
>>>>         
>>>>> Hi,
>>>>> I have a suggestion about /proc/net/IPv6_route format.
>>>>> In rt6_info_route(), interface name is treated as a maximum 8
>>>>> characters.
>>>>> But the type of (struct rt6_inf *)->u.dst.dev->name is char[IFNAMESIZ=
>>>>> 16]
>>>>> so, I think that it should change "%8s" to "%16s".
>>>>>           
>>>> Isn't there a way to pass the field length as a paramenter
>>>> to formatting functions?  Then we can just pass in
>>>> IFNAMESIZE as that parameter.
>>>>         
>>> 	seq_printf(m, " %08x %08x %08x %08x %*s\n"
>>>                    rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
>>>  		   rt->u.dst.__use, rt->rt6i_flags,
>>>                    IFNAMESIZE, 
>>>  		   rt->rt6i_dev ? rt->rt6i_dev->name : "")
>>>       
>> Actually since it is the last item on the line a field width does not
>> make much sense, and omitting it would print the name left justified.
>>
>> (And RT6_INFO_LEN is not used any more.)
>>
>> Andreas.
>>
>>     
>
> The issue is what happens if name is not null terminated. in this case
> I bet the kernel already handles that.
>
>   


[-- Attachment #2: ipv6_route_ifnamesiz2.patch --]
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diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1394ddb..a532dda 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2434,7 +2434,8 @@ static int ip6_route_dev_notify(struct notifier_block *this,
 
 #ifdef CONFIG_PROC_FS
 
-#define RT6_INFO_LEN (32 + 4 + 32 + 4 + 32 + 40 + 5 + 1)
+#define RT6_INFO_LEN (32 + 4 + 32 + 4 + 32 + 48 + 5 + 1)
+#define RT6_VAL_TO_STR(s) #s
 
 struct rt6_proc_arg
 {
@@ -2462,7 +2463,8 @@ static int rt6_info_route(struct rt6_info *rt, void *p_arg)
 	} else {
 		seq_puts(m, "00000000000000000000000000000000");
 	}
-	seq_printf(m, " %08x %08x %08x %08x %8s\n",
+	seq_printf(m, " %08x %08x %08x %08x %"
+		   RT6_VAL_TO_STR(IFNAMSIZ) "s\n",
 		   rt->rt6i_metric, atomic_read(&rt->u.dst.__refcnt),
 		   rt->u.dst.__use, rt->rt6i_flags,
 		   rt->rt6i_dev ? rt->rt6i_dev->name : "");

Re: [IPV6]: ROUTE:read ifname in rt6_info_route()

[Andreas Schwab]

Stephen Hemminger <shemminger@vyatta.com> writes:

> The issue is what happens if name is not null terminated.

That cannot happen.  And a field width would not help anyway.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."