From b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c Mon Sep 17 00:00:00 2001 From: Matt Domsch Date: Tue, 8 Nov 2005 09:40:47 -0800 Subject: [PPP]: add PPP MPPE encryption module From: Matt Domsch 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 please. Signed-off-by: Matt Domsch Cc: James Cameron Cc: "David S. Miller" Signed-off-by: Brice Goglin Acked-by: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- drivers/net/ppp_mppe.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 drivers/net/ppp_mppe.h (limited to 'drivers/net/ppp_mppe.h') diff --git a/drivers/net/ppp_mppe.h b/drivers/net/ppp_mppe.h new file mode 100644 index 00000000000..7a14e058c66 --- /dev/null +++ b/drivers/net/ppp_mppe.h @@ -0,0 +1,86 @@ +#define MPPE_PAD 4 /* MPPE growth per frame */ +#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */ + +/* option bits for ccp_options.mppe */ +#define MPPE_OPT_40 0x01 /* 40 bit */ +#define MPPE_OPT_128 0x02 /* 128 bit */ +#define MPPE_OPT_STATEFUL 0x04 /* stateful mode */ +/* unsupported opts */ +#define MPPE_OPT_56 0x08 /* 56 bit */ +#define MPPE_OPT_MPPC 0x10 /* MPPC compression */ +#define MPPE_OPT_D 0x20 /* Unknown */ +#define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D) +#define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */ + +/* + * This is not nice ... the alternative is a bitfield struct though. + * And unfortunately, we cannot share the same bits for the option + * names above since C and H are the same bit. We could do a u_int32 + * but then we have to do a htonl() all the time and/or we still need + * to know which octet is which. + */ +#define MPPE_C_BIT 0x01 /* MPPC */ +#define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */ +#define MPPE_L_BIT 0x20 /* 40-bit */ +#define MPPE_S_BIT 0x40 /* 128-bit */ +#define MPPE_M_BIT 0x80 /* 56-bit, not supported */ +#define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */ + +/* Does not include H bit; used for least significant octet only. */ +#define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT) + +/* Build a CI from mppe opts (see RFC 3078) */ +#define MPPE_OPTS_TO_CI(opts, ci) \ + do { \ + u_char *ptr = ci; /* u_char[4] */ \ + \ + /* H bit */ \ + if (opts & MPPE_OPT_STATEFUL) \ + *ptr++ = 0x0; \ + else \ + *ptr++ = MPPE_H_BIT; \ + *ptr++ = 0; \ + *ptr++ = 0; \ + \ + /* S,L bits */ \ + *ptr = 0; \ + if (opts & MPPE_OPT_128) \ + *ptr |= MPPE_S_BIT; \ + if (opts & MPPE_OPT_40) \ + *ptr |= MPPE_L_BIT; \ + /* M,D,C bits not supported */ \ + } while (/* CONSTCOND */ 0) + +/* The reverse of the above */ +#define MPPE_CI_TO_OPTS(ci, opts) \ + do { \ + u_char *ptr = ci; /* u_char[4] */ \ + \ + opts = 0; \ + \ + /* H bit */ \ + if (!(ptr[0] & MPPE_H_BIT)) \ + opts |= MPPE_OPT_STATEFUL; \ + \ + /* S,L bits */ \ + if (ptr[3] & MPPE_S_BIT) \ + opts |= MPPE_OPT_128; \ + if (ptr[3] & MPPE_L_BIT) \ + opts |= MPPE_OPT_40; \ + \ + /* M,D,C bits */ \ + if (ptr[3] & MPPE_M_BIT) \ + opts |= MPPE_OPT_56; \ + if (ptr[3] & MPPE_D_BIT) \ + opts |= MPPE_OPT_D; \ + if (ptr[3] & MPPE_C_BIT) \ + opts |= MPPE_OPT_MPPC; \ + \ + /* Other bits */ \ + if (ptr[0] & ~MPPE_H_BIT) \ + opts |= MPPE_OPT_UNKNOWN; \ + if (ptr[1] || ptr[2]) \ + opts |= MPPE_OPT_UNKNOWN; \ + if (ptr[3] & ~MPPE_ALL_BITS) \ + opts |= MPPE_OPT_UNKNOWN; \ + } while (/* CONSTCOND */ 0) -- cgit v1.2.3