Passing argument to setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,intr)

[Richard Taylor]

Hi

Does anyone know the correct way to pass the 'device' argument to setsockopt
with the SO_BINDTODEVICE flag?

I have tried various methods:

setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,"eth0")
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,inet_aton("eth0"))
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("s","eth0"))
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("p","eth0"))

None of these work. I just get a "socket.error: (19, 'No such device')".

I do have an "eth0" device

Many thanks

Richard

 

[Richard Taylor]

Hi

Does anyone know the correct way to pass the 'device' argument to
setsockopt with the SO_BINDTODEVICE flag?

I have tried various methods:

setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,"eth0")
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,inet_aton("eth0"))
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("s","eth0"))
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("p","eth0"))

None of these work. I just get a "socket.error: (19, 'No such device')".

I do have an "eth0" device

Many thanks

Richard

Solved it!

So for others that find this in the news archive...

The answer is:

s.setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("%ds" %
(len("eth0")+1,), "eth0"))

Richard

 

[Jeff Epler]

The answer is:

s.setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("%ds" %
(len("eth0")+1,), "eth0"))
Richard Taylor wrote:

Maybe this is simpler:
#dev = "eth0"
s.setsockopt(..., dev + '\0')
I think it has the same effect as your code, but it is a little clearer
to me that the setsockopt call needs a zero-terminated C string as its
argument.

Jeff

 

[Richard Taylor]

Maybe this is simpler:
#dev = "eth0"
s.setsockopt(..., dev + '\0')
I think it has the same effect as your code, but it is a little clearer
to me that the setsockopt call needs a zero-terminated C string as its
argument.

Jeff

You are right. I did not realise that you could append a null in that way.

Thanks.

Richard

 

[Guest]

Does anyone know the correct way to pass the 'device' argument to

setsockopt with the SO_BINDTODEVICE flag?

I have tried various methods:

setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,"eth0")
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,inet_aton("eth0"))
setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("s","eth0"))

I think you need
struct.pack("5s","eth0")