/* * Another PPP variant as per request from Karsten Keil <kkeil@suse.de>. * * This is used in some OSes to allow a kernel socket filter to distinguish * between incoming and outgoing packets, on a socket intended to * supply pppd with outgoing packets so it can do dial-on-demand and * hangup-on-lack-of-demand; incoming packets are filtered out so they * don't cause pppd to hold the connection up (you don't want random * input packets such as port scans, packets from old lost connections, * etc. to force the connection to stay up). * * The first byte of the PPP header (0xff03) is modified to accomodate * the direction - 0x00 = IN, 0x01 = OUT. */