set/getsockopt SO_LINGER problem

Hi,

I am trying to use get/setsockopt for SO_LINGER option but
am facing a 
problem
I used setsockopt with opt as SO_LINGER passing linger
structure with 
l_onoff as 1 and l_linger as 65535
but when I try to get back through getsockopt, I am getting
l_onoff as 
128 and l_linger as -1.
For other values of l_linger (like 1, 2, 10) during set,
though I get 
l_onoff as 128 but l_linger is returned correctly
Before getting the value, I typecast the (void *)optval to
(linger *). 
Has anyone seen this problem before in Netbsd 3.0?

Regards
Prasanta

On Wed, Dec 06, 2006 at 01:03:56PM +0530, Prasanta Sadhukhan
wrote:
> Hi,
> 
> I am trying to use get/setsockopt for SO_LINGER option
but am facing a 
> problem
> I used setsockopt with opt as SO_LINGER passing linger
structure with 
> l_onoff as 1 and l_linger as 65535
> but when I try to get back through getsockopt, I am
getting l_onoff as 
> 128 and l_linger as -1.
> For other values of l_linger (like 1, 2, 10) during
set, though I get 
> l_onoff as 128 but l_linger is returned correctly

I suspect this has something to do with:
    /usr/include/sys/socketvar.h:   short    so_linger;
and:
    /usr/include/sys/socket.h: #define SO_LINGER     0x0080

	David

-- 
David Laight: davidl8s.co.uk

David Laight wrote:

>On Wed, Dec 06, 2006 at 01:03:56PM +0530, Prasanta
Sadhukhan wrote:
>  
>
>>Hi,
>>
>>I am trying to use get/setsockopt for SO_LINGER
option but am facing a 
>>problem
>>I used setsockopt with opt as SO_LINGER passing
linger structure with 
>>l_onoff as 1 and l_linger as 65535
>>but when I try to get back through getsockopt, I am
getting l_onoff as 
>>128 and l_linger as -1.
>>For other values of l_linger (like 1, 2, 10) during
set, though I get 
>>l_onoff as 128 but l_linger is returned correctly
>>    
>>
>
>I suspect this has something to do with:
>    /usr/include/sys/socketvar.h:   short    so_linger;
>and:
>    /usr/include/sys/socket.h: #define SO_LINGER    
0x0080
>
>	David
>
>  
>
I have attached a program that shows the problem. Is it a
known issue 
with NetBSD3.0?

Regards
Prasanta

The following code in src/sys/kern/uipc_socket.c#sogetopt()
seems to be 
the culprit in my opinion

mtod(m, struct linger *)->l_onoff = so->so_options
& SO_LINGER;
mtod(m, struct linger *)->l_linger = so->so_linger;

Since SO_LINGER is 0x80, I am getting 128
also so->so_linger is short unlike l_linger which is int
so anything 
 >32767 is curtailed

Regards
Prasanta
Prasanta Sadhukhan wrote:

> David Laight wrote:
>
>> On Wed, Dec 06, 2006 at 01:03:56PM +0530, Prasanta
Sadhukhan wrote:
>>  
>>
>>> Hi,
>>>
>>> I am trying to use get/setsockopt for SO_LINGER
option but am facing 
>>> a problem
>>> I used setsockopt with opt as SO_LINGER passing
linger structure 
>>> with l_onoff as 1 and l_linger as 65535
>>> but when I try to get back through getsockopt,
I am getting l_onoff 
>>> as 128 and l_linger as -1.
>>> For other values of l_linger (like 1, 2, 10)
during set, though I 
>>> get l_onoff as 128 but l_linger is returned
correctly
>>>   
>>
>>
>> I suspect this has something to do with:
>>    /usr/include/sys/socketvar.h:   short   
so_linger;
>> and:
>>    /usr/include/sys/socket.h: #define SO_LINGER    
0x0080
>>
>>     David
>>
>>  
>>
> I have attached a program that shows the problem. Is it
a known issue 
> with NetBSD3.0?
>
> Regards
> Prasanta
>
>--------------------------------------------------------
----------------
>
>#include <stdio.h>
>#include <sys/socket.h>
>
>void testlinger();
>
>int main(int argc, char *argv[])
>{
>	testlinger();
>}
>
>void testlinger()
>{
>	int fd, ret, optlen;
>	union {
>		int i;
>		struct linger ling;
>	} optval;
>	void *result;
>	fd = socket(PF_INET, SOCK_DGRAM, 0);
>	printf("socket fd %dn", fd);
>	
>	struct linger ling;
>	optval.ling.l_onoff = 1;
>	optval.ling.l_linger = 65535;
>	optlen = sizeof(optval.ling);
>	ret = setsockopt(fd, SOL_SOCKET, SO_LINGER, (const void
*)&optval, optlen);
>	printf("setsockopt retval %d, optlen %dn",
ret,optlen);
>
>	ret = getsockopt(fd, SOL_SOCKET, SO_LINGER, result,
&optlen);
>	printf("getsockopt retval %dn", ret);
>	printf("get linger onoff %d, linger value %d,
optlen %dn",
>			((struct linger*)result)->l_onoff,
>			((struct linger*)result)->l_linger, optlen);
>}
>	
>  
>