Re: Netlink error datagrams

[Patrick McHardy <kaber@trash.net>]

Ross Vandegrift wrote:
> Hello everyone,
> 
> I have a libipq application that I'm using with netfilter.  I have the
> following fragment of code, mostly from the FAQ:
> 
>       status = ipq_read(h, buf, BUFSIZE, 0);
>       if (status < 0)
> 	rr_err ("%s", ipq_errstr ());
>       
>       switch (ipq_message_type(buf))
> 	{
> 	case IPQM_PACKET:
>           /* Do stuff with the packet */
>           break;
> 
> 	case NLMSG_ERROR:
>           ipq_perror ("rrfilter");
> 
> 
> In my production boxes, I'm hitting the NLMSG_ERROR case pretty
> frequently - as often as every minute.  It doesn't seem to adversely
> affect packet processing, but I'm not sure because I can only
> reproduce it with real traffic.
> 
> I've attached via gdb and the netlink messages I'm getting are just a
> header and the four bytes of padding.  ipq_perror reports "Unknown
> failure".


What error code does the header contain?