Date: Fri, 21 Mar 2008 11:40:48 -0700 From: Julian Elischer <julian@elischer.org> To: Brett Glass <brett@lariat.net> Cc: net@freebsd.org Subject: Re: GRE Mux Message-ID: <47E40130.1000901@elischer.org> In-Reply-To: <200803211547.JAA28265@lariat.net> References: <200803211547.JAA28265@lariat.net>
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Brett Glass wrote: > Everyone: > > I have recently been building FreeBSD VPN servers which can accept 50 to > 100 PPTP connections. PPTP is, essentially, PPP over GRE (with a TCP > control connection), so we have large numbers of packets passing in and > out using GRE. Unfortunately, GRE on FreeBSD doesn't currently have a > multiplexing function as does TCP. If userland PPP and pptpd are used to > handle the PPTP sessions, each GRE packet is passed to the first pptpd > process. If the call ID doesn't match, it's passed to the next, and then > the next, and so on. What's more, each test requires a "bounce" into and > out of the kernel. mpd, which uses netgraph, does more of the work > within the kernel, but the testing still takes place in linear time -- > and the potential delay increases with the number of PPTP sessions that > have been established. The packet is bounced from one netgraph node to > another until one of them accepts it or the packet falls off the end of > the chain. > > It seems to me that it might be worth it to implement a multiplexing > function that dispatches the packet directly to the right process or > netgraph node rather than passing it from hand to hand. Thoughts? if it takes you more than 1 day to write a netgraph function to do it you are taking too many coffee breaks. mpd could probably do it automatically as it already does a lot of netgraph munging. > > --Brett Glass > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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