Re: Libpcap reentrancy and PF_RING patch

[Luca Deri <deri () ntop org>]

Guy
as I have explained in my previous reply, I don't think you're going  
to use simultaneously pcap_loop and pcap_next_pkt, so I don't see a  
problem here. However, this problem can be overcome by an if statement  
like the one below

              if(buf == handle->buffer) { <--- we use the shared  
buffer hence we have been called by pcap_loop etc.
                /*
                 * Has "pcap_breakloop()" been called?
                 */
                if (handle->break_loop) {
                        /*
                         * Yes - clear the flag that indicates that it
                         * has, and return -2 as an indication that we
                         * were told to break out of the loop.
                         */
                        handle->break_loop = 0;
                        return -2;
                }
                }

What do you think?

Regards, Luca


On Jan 1, 2008, at 10:24 PM, Guy Harris wrote:

> Guy Harris wrote:
>
> > Unless I'm misinterpreting socket(7), at least on Linux systems  
> > with the SO_TIMESTAMP socket option, you can set that option and  
> > use recvmsg() to read a packet; the control message for the packet  
> > will contain the time stamp.
>
> ...although that doesn't address the issue of the read-modify fields  
> in the pcap handle - which *are* significant, so the reentrancy  
> problem is, as Gregor notes, harder to fix.
> -
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