ng_mppc_decompress: too many (4094) packets dropped, disabling node

[Sami Halabi]

Hi,
is setting these sysctl's that high recommended? i don't really know what
they mean, and honestly didn't search to see what they do, i simply tried
to set them high in order to improve the service.

if its recommended, then i would test these changes if they will be done.

Sami

2012/1/5 Gleb Smirnoff <glebius at freebsd.org>

> On Thu, Jan 05, 2012 at 03:43:45PM +0200, Sami Halabi wrote:
> S> Hmm..
> S>
> S> Somthing strange, i did:
> S> net.graph.recvspace=8388608
> S> net.graph.maxdgram=8388608
> S>
> S>
> S> and i suddenly got disconnections and logs like:
> S> Jan  5 16:10:01 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:11 mpd2 mpd: PPTP: NgMkSockNode: No buffer space available
> S>
> S> the mpd as follows:
> S>
> S> Jan  5 16:10:01 mpd2 mpd: Incoming L2TP packet from 172.25.229.3 1701
> S> Jan  5 16:10:01 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:01 mpd2 mpd: Incoming L2TP packet from 172.27.173.112 1701
> S> Jan  5 16:10:01 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:03 mpd2 mpd: Incoming L2TP packet from 172.19.246.206 1701
> S> Jan  5 16:10:03 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:06 mpd2 mpd: Incoming L2TP packet from 172.27.173.112 1701
> S> Jan  5 16:10:06 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Accepting PPTP connection
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: OPEN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Open event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: state change Initial --> Starting
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: LayerStart
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] PPTP: attaching to peer's outgoing call
> S> Jan  5 16:10:11 mpd2 mpd: PPTP: NgMkSockNode: No buffer space available
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] PPTP call cancelled in state CONNECTING
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: DOWN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Close event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: state change Starting --> Initial
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: LayerFinish
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Down event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: SHUTDOWN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: Shutdown
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Accepting PPTP connection
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: OPEN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Open event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: state change Initial --> Starting
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: LayerStart
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] PPTP: attaching to peer's outgoing call
> S> Jan  5 16:10:11 mpd2 mpd: PPTP: NgMkSockNode: No buffer space available
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] PPTP call cancelled in state CONNECTING
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: DOWN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Close event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: state change Starting --> Initial
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: LayerFinish
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] LCP: Down event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: SHUTDOWN event
> S> Jan  5 16:10:11 mpd2 mpd: [L-14] Link: Shutdown
> S> Jan  5 16:10:16 mpd2 mpd: Incoming L2TP packet from 172.27.173.112 1701
> S> Jan  5 16:10:16 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:21 mpd2 mpd: Incoming L2TP packet from 172.25.229.3 1701
> S> Jan  5 16:10:21 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S> Jan  5 16:10:23 mpd2 mpd: Incoming L2TP packet from 172.19.246.206 1701
> S> Jan  5 16:10:23 mpd2 mpd: L2TP: ppp_l2tp_ctrl_create: No buffer space
> S> available
> S>
> S>
> S> Now i just returned to my original sysctl:
> S> net.graph.recvspace=40960
> S> net.graph.maxdgram=40960
> S>
> S> and everything seems fine
> S>
> S> any ideas?
>
> mpd has many open sockets, and each socket allocates that much recvspace
> and sendspace. Since there are a lot of them, it hits per-user resource
> limits, I suppose.
>
> We need to:
>
> 1) Change mpd to use one control socket with many hooks.
>   This also requires improving ng_socket, to have a fast hook lookup
>   method.
>
> 2) Implement SO_SNDBUF/SO_RCVBUF for AF_NETGRAPH socket, and utilize
>   it in ngctl, so there would be no need to bump global tunables.
>
> Eventually I may do this, but I need brave testers, since my mpd
> installation is very small.
>
> --
> Totus tuus, Glebius.
>



-- 
Sami Halabi
Information Systems Engineer
NMS Projects Expert