[PPP]: add PPP MPPE encryption module
From: Matt Domsch <Matt_Domsch@dell.com>
The patch below implements the Microsoft Point-to-Point Encryption method
as a PPP compressor/decompressor. This is necessary for Linux clients and
servers to interoperate with Microsoft Point-to-Point Tunneling Protocol
(PPTP) servers (either Microsoft PPTP servers or the poptop project) which
use MPPE to encrypt data when creating a VPN.
This patch differs from the kernel_ppp_mppe DKMS pacakge at
pptpclient.sourceforge.net by utilizing the kernel crypto routines rather
than providing its own SHA1 and arcfour implementations.
Minor changes to ppp_generic.c try to prevent a link from disabling
compression (in our case, the encryption) after it has started using
compression (encryption).
Feedback to <pptpclient-devel@lists.sourceforge.net> please.
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Cc: James Cameron <james.cameron@hp.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ppp-comp.h b/include/linux/ppp-comp.h
index 7227e65..e86a7a5 100644
--- a/include/linux/ppp-comp.h
+++ b/include/linux/ppp-comp.h
@@ -111,6 +111,8 @@
/* Used in locking compressor modules */
struct module *owner;
+ /* Extra skb space needed by the compressor algorithm */
+ unsigned int comp_extra;
};
/*
@@ -191,6 +193,13 @@
#define DEFLATE_CHK_SEQUENCE 0
/*
+ * Definitions for MPPE.
+ */
+
+#define CI_MPPE 18 /* config option for MPPE */
+#define CILEN_MPPE 6 /* length of config option */
+
+/*
* Definitions for other, as yet unsupported, compression methods.
*/