Re: [RESEND PATCH 1/1] netfilter: load nf_log_syslog on enabling nf_conntrack_log_invalid

[Florian Westphal <fw@strlen.de>]

Lance Yang <lance.yang@linux.dev> wrote:
> > There is no need for 'syslog' to be active for 'log_invalid' to be
> > useful as long as the system in question has e.g. ulogd running
> > and listening to nflog messages.
> > 
> > If anything, the modprobe should be done only when no logger
> > is registered.
> 
> Yes, could we load the module only when no logger exists? Something
> like:
> 
> + if (nf_logger_find_get(NFPROTO_IPV4, NF_LOG_TYPE_LOG) != 0)
> + 	request_module("%s", "nf_log_syslog");

This function bumps the module refcount, so if the logger exists you
would need to call nf_logger_put() too.

I'd add a new, simpler helper, that only returns if any logger
is active.

bool nf_log_is_registered(int pf);

or something like that.