linux/net/l2tp
Sam Protsenko c151acc6e9 l2tp: Add protocol field decompression
When Protocol Field Compression (PFC) is enabled, the "Protocol" field
in PPP packet will be received without leading 0x00. See section 6.5 in
RFC 1661 for details. So let's decompress protocol field if needed, the
same way it's done in drivers/net/ppp/pptp.c.

In case when "nopcomp" pppd option is not enabled, PFC (pcomp) can be
negotiated during LCP handshake, and L2TP driver in kernel will receive
PPP packets with compressed Protocol field, which in turn leads to next
error:

    Protocol Rejected (unsupported protocol 0x2145)

because instead of Protocol=0x0021 in PPP packet there will be
Protocol=0x21. This patch unwraps it back to 0x0021, which fixes the
issue.

Sending the compressed Protocol field will be implemented in subsequent
patch, this one is self-sufficient.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-15 23:28:19 -08:00
..
Kconfig l2tp: Call udp_sock_create 2014-07-14 16:12:15 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
l2tp_core.c l2tp: fix a sock refcnt leak in l2tp_tunnel_register 2018-11-14 22:49:31 -08:00
l2tp_core.h l2tp: fix unused function warning 2018-08-13 20:45:49 -07:00
l2tp_debugfs.c l2tp: ignore L2TP_ATTR_MTU 2018-08-03 10:03:57 -07:00
l2tp_eth.c l2tp: fix unused function warning 2018-08-13 20:45:49 -07:00
l2tp_ip.c l2tp: split l2tp_session_get() 2018-08-11 12:13:49 -07:00
l2tp_ip6.c l2tp: split l2tp_session_get() 2018-08-11 12:13:49 -07:00
l2tp_netlink.c l2tp: split l2tp_session_get() 2018-08-11 12:13:49 -07:00
l2tp_ppp.c l2tp: Add protocol field decompression 2018-12-15 23:28:19 -08:00