dtrace discuss - May 2010 - ?: DTrace of connection establishment attempts for destination address/port

Using Solaris 10, so no IP provider, I am trying to figure out when a
connection attempt is failing in a client. The connect() statement takes
a file descriptor, which is an integer and has no connection details.
Since I don''t know if the connect is closely preceded with a bind() or
a
new connection may be attempted with the same socket, and thus I won''t 
be capturing the bin, I can''t rely on it to get the sockaddr structure.

(The event happens very infrequently, maybe once a day)

So I am trying tcp_connect FBT probe.

fbt::tcp_connect:entry
{
        printf("execname: %s \n", execname);
        self->sockaddr = args[1];

        printf("family: %x \n", self->sockaddr->sa_family);
}

However, I get

# /var/tmp/connect.d
dtrace: failed to compile script /var/tmp/connect.d: line 32: sa_family
is not a member of struct msgb

Note is says ''msgb'', not ''sockaddr''.

I got the args[1] from the OpenSolaris source code (and maybe that is my
problem, since I am running on Solaris 10--did the code change that
much?--seems unlikely)

http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/inet/tcp/tcp_socket.c#232

Any good way to grab the IPv4 address and port number on an entry so I
can have it in the situation the connect() fails?

Thanks
Steffen

Hi Steffen - I actually think that code did change quite a bit
from s10 to nv.

I''m not sure what you need to do, but you may want to grab
Brendan''s DTraceToolKit and have a look at tcptop and
tcpsnoop, and have a look at how Brendan did it for s10.

Thanks,
/jim

On May 5, 2010, at 8:21 AM, Steffen Weiberle wrote:
> Using Solaris 10, so no IP provider, I am trying to figure out when a
> connection attempt is failing in a client. The connect() statement takes
> a file descriptor, which is an integer and has no connection details.
> Since I don''t know if the connect is closely preceded with a
bind() or a new connection may be attempted with the same socket, and thus I
won''t be capturing the bin, I can''t rely on it to get the
sockaddr structure.
> 
> (The event happens very infrequently, maybe once a day)
> 
> So I am trying tcp_connect FBT probe.
> 
> fbt::tcp_connect:entry
> {
>       printf("execname: %s \n", execname);
>       self->sockaddr = args[1];
> 
>       printf("family: %x \n", self->sockaddr->sa_family);
> }
> 
> However, I get
> 
> # /var/tmp/connect.d
> dtrace: failed to compile script /var/tmp/connect.d: line 32: sa_family
> is not a member of struct msgb
> 
> Note is says ''msgb'', not ''sockaddr''.
> 
> I got the args[1] from the OpenSolaris source code (and maybe that is my
> problem, since I am running on Solaris 10--did the code change that
> much?--seems unlikely)
> 
>
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/inet/tcp/tcp_socket.c#232
> 
> Any good way to grab the IPv4 address and port number on an entry so I
> can have it in the situation the connect() fails?
> 
> Thanks
> Steffen
> 
> 
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org

Hi,

Steffen Weiberle wrote:
> Using Solaris 10, so no IP provider, I am trying to figure out when a
> connection attempt is failing in a client. The connect() statement takes
> a file descriptor, which is an integer and has no connection details.
> Since I don''t know if the connect is closely preceded with a
bind() or
> a new connection may be attempted with the same socket, and thus I 
> won''t be capturing the bin, I can''t rely on it to get the
sockaddr
> structure.
>
> (The event happens very infrequently, maybe once a day)
>
> So I am trying tcp_connect FBT probe.
>
> fbt::tcp_connect:entry
> {
>        printf("execname: %s \n", execname);
>        self->sockaddr = args[1];
>
>        printf("family: %x \n", self->sockaddr->sa_family);
> }
>
> However, I get
>
> # /var/tmp/connect.d
> dtrace: failed to compile script /var/tmp/connect.d: line 32: sa_family
> is not a member of struct msgb
>
> Note is says ''msgb'', not ''sockaddr''.
Try:

    self->sockaddr = (struct sockaddr *) args[1]->b_rptr;

struct msgb is a STREAMS mblk_t.

max
>
> I got the args[1] from the OpenSolaris source code (and maybe that is my
> problem, since I am running on Solaris 10--did the code change that
> much?--seems unlikely)
>
>
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/inet/tcp/tcp_socket.c#232
>
>
> Any good way to grab the IPv4 address and port number on an entry so I
> can have it in the situation the connect() fails?
>
> Thanks
> Steffen
>
>
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
>

On 05/05/10 09:20, Jim Mauro wrote:
> Hi Steffen - I actually think that code did change quite a bit
> from s10 to nv.
>
> I''m not sure what you need to do, but you may want to grab
> Brendan''s DTraceToolKit and have a look at tcptop and
> tcpsnoop, and have a look at how Brendan did it for s10.
>   
Hi Jim, thanks. I did. In the tcp_connect in tcptop he only used arg0. 
The connections did not have anything that I could see.

Just tried to run the two, and neither works on 10/09 :(

Steffen
> Thanks,
> /jim
>
> On May 5, 2010, at 8:21 AM, Steffen Weiberle wrote:
>
>   
>> Using Solaris 10, so no IP provider, I am trying to figure out when a
>> connection attempt is failing in a client. The connect() statement
takes
>> a file descriptor, which is an integer and has no connection details.
>> Since I don''t know if the connect is closely preceded with a
bind() or a new connection may be attempted with the same socket, and thus I
won''t be capturing the bin, I can''t rely on it to get the
sockaddr structure.
>>
>> (The event happens very infrequently, maybe once a day)
>>
>> So I am trying tcp_connect FBT probe.
>>
>> fbt::tcp_connect:entry
>> {
>>       printf("execname: %s \n", execname);
>>       self->sockaddr = args[1];
>>
>>       printf("family: %x \n",
self->sockaddr->sa_family);
>> }
>>
>> However, I get
>>
>> # /var/tmp/connect.d
>> dtrace: failed to compile script /var/tmp/connect.d: line 32: sa_family
>> is not a member of struct msgb
>>
>> Note is says ''msgb'', not
''sockaddr''.
>>
>> I got the args[1] from the OpenSolaris source code (and maybe that is
my
>> problem, since I am running on Solaris 10--did the code change that
>> much?--seems unlikely)
>>
>>
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/inet/tcp/tcp_socket.c#232
>>
>> Any good way to grab the IPv4 address and port number on an entry so I
>> can have it in the situation the connect() fails?
>>
>> Thanks
>> Steffen
>>
>>
>> _______________________________________________
>> dtrace-discuss mailing list
>> dtrace-discuss at opensolaris.org
>>     
>
>   
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On 05/05/2010 13:21, Steffen Weiberle wrote:
> Using Solaris 10, so no IP provider, I am trying to figure out when a
> connection attempt is failing in a client. The connect() statement takes
> a file descriptor, which is an integer and has no connection details.
> Since I don''t know if the connect is closely preceded with a
bind() or
> a new connection may be attempted with the same socket, and thus I 
> won''t be capturing the bin, I can''t rely on it to get the
sockaddr
> structure.
>
Just wanted to note that this sort of thing will become easier
(for Nevada at least) when the tcp provider delivers (which
should be soon):

tcp:::connect-refused
{
     printf("connection refused: pid %d, remote host/port %s/%d\n",
         args[1]->cs_pid, args[3]->tcps_raddr, args[3]->tcps_rport);
}

Alan
> (The event happens very infrequently, maybe once a day)
>
> So I am trying tcp_connect FBT probe.
>
> fbt::tcp_connect:entry
> {
>        printf("execname: %s \n", execname);
>        self->sockaddr = args[1];
>
>        printf("family: %x \n", self->sockaddr->sa_family);
> }
>
> However, I get
>
> # /var/tmp/connect.d
> dtrace: failed to compile script /var/tmp/connect.d: line 32: sa_family
> is not a member of struct msgb
>
> Note is says ''msgb'', not ''sockaddr''.
>
> I got the args[1] from the OpenSolaris source code (and maybe that is my
> problem, since I am running on Solaris 10--did the code change that
> much?--seems unlikely)
>
>
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/inet/tcp/tcp_socket.c#232
>
>
> Any good way to grab the IPv4 address and port number on an entry so I
> can have it in the situation the connect() fails?
>
> Thanks
> Steffen
>
>
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org