Re: Accessing packet marking functions

[Andrew Beverley <andy@andybev.com>]

> >Can somebody point me in the right direction for the correct way of
> >setting and accessing the mark value of a packet? The TOS feature in
> >Squid uses setsockopt(). Is there an equivalent for mark? Should I be
> >using libnetfilter_queue?
> 
> setsockopt(fd, SOL_SOCKET, SO_MARK, ...)

I am getting the error "Operation not permitted" when trying to do this.
Is this because the packet is not in a state where it can be marked, or
am I doing something stupid? My code is:

int nfmark = 255;
setsockopt(fd, SOL_SOCKET, SO_MARK, (int *) &nfmark, sizeof(int));


The following lines of code in the same place work okay to set the TOS:

int nfmark = 255;
setsockopt(fd, IPPROTO_IP, IP_TOS, (int *) &nfmark, sizeof(int));


Thanks,

Andy