/* * ppp_mppe.c - interface MPPE to the PPP code. * This version is for use with Linux kernel 2.6.14+ * * By Frank Cusack <[email protected]>. * Copyright (c) 2002,2003,2004 Google, Inc. * All rights reserved. * * License: * Permission to use, copy, modify, and distribute this software and its * documentation is hereby granted, provided that the above copyright * notice appears in all copies. This software is provided without any * warranty, express or implied. * * ALTERNATIVELY, provided that this notice is retained in full, this product * may be distributed under the terms of the GNU General Public License (GPL), * in which case the provisions of the GPL apply INSTEAD OF those given above. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see <http://www.gnu.org/licenses/>. * * * Changelog: * 08/12/05 - Matt Domsch <[email protected]> * Only need extra skb padding on transmit, not receive. * 06/18/04 - Matt Domsch <[email protected]>, Oleg Makarenko <[email protected]> * Use Linux kernel 2.6 arc4 and sha1 routines rather than * providing our own. * 2/15/04 - TS: added #include <version.h> and testing for Kernel * version before using * MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are * deprecated in 2.6 */ #include <crypto/arc4.h> #include <crypto/hash.h> #include <linux/err.h> #include <linux/fips.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/types.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/ppp_defs.h> #include <linux/ppp-comp.h> #include <linux/scatterlist.h> #include <asm/unaligned.h> #include "ppp_mppe.h" MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; MODULE_ALIAS(…) …; MODULE_VERSION(…) …; #define SHA1_PAD_SIZE … /* * kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module * static data area. That means sha_pad needs to be kmalloc'd. */ struct sha_pad { … }; static struct sha_pad *sha_pad; static inline void sha_pad_init(struct sha_pad *shapad) { … } /* * State for an MPPE (de)compressor. */ struct ppp_mppe_state { … }; /* struct ppp_mppe_state.bits definitions */ #define MPPE_BIT_A … #define MPPE_BIT_B … #define MPPE_BIT_C … #define MPPE_BIT_D … #define MPPE_BIT_FLUSHED … #define MPPE_BIT_ENCRYPTED … #define MPPE_BITS(p) … #define MPPE_CCOUNT(p) … #define MPPE_CCOUNT_SPACE … #define MPPE_OVHD … #define SANITY_MAX … /* * Key Derivation, from RFC 3078, RFC 3079. * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079. */ static void get_new_key_from_sha(struct ppp_mppe_state * state) { … } /* * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3. * Well, not what's written there, but rather what they meant. */ static void mppe_rekey(struct ppp_mppe_state * state, int initial_key) { … } /* * Allocate space for a (de)compressor. */ static void *mppe_alloc(unsigned char *options, int optlen) { … } /* * Deallocate space for a (de)compressor. */ static void mppe_free(void *arg) { … } /* * Initialize (de)compressor state. */ static int mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug, const char *debugstr) { … } static int mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit, int hdrlen, int debug) { … } /* * We received a CCP Reset-Request (actually, we are sending a Reset-Ack), * tell the compressor to rekey. Note that we MUST NOT rekey for * every CCP Reset-Request; we only rekey on the next xmit packet. * We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost. * So, rekeying for every CCP Reset-Request is broken as the peer will not * know how many times we've rekeyed. (If we rekey and THEN get another * CCP Reset-Request, we must rekey again.) */ static void mppe_comp_reset(void *arg) { … } /* * Compress (encrypt) a packet. * It's strange to call this a compressor, since the output is always * MPPE_OVHD + 2 bytes larger than the input. */ static int mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf, int isize, int osize) { … } /* * Since every frame grows by MPPE_OVHD + 2 bytes, this is always going * to look bad ... and the longer the link is up the worse it will get. */ static void mppe_comp_stats(void *arg, struct compstat *stats) { … } static int mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit, int hdrlen, int mru, int debug) { … } /* * We received a CCP Reset-Ack. Just ignore it. */ static void mppe_decomp_reset(void *arg) { … } /* * Decompress (decrypt) an MPPE packet. */ static int mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, int osize) { … } /* * Incompressible data has arrived (this should never happen!). * We should probably drop the link if the protocol is in the range * of what should be encrypted. At the least, we should drop this * packet. (How to do this?) */ static void mppe_incomp(void *arg, unsigned char *ibuf, int icnt) { … } /************************************************************* * Module interface table *************************************************************/ /* * Procedures exported to if_ppp.c. */ static struct compressor ppp_mppe = …; /* * ppp_mppe_init() * * Prior to allowing load, try to load the arc4 and sha1 crypto * libraries. The actual use will be allocated later, but * this way the module will fail to insmod if they aren't available. */ static int __init ppp_mppe_init(void) { … } static void __exit ppp_mppe_cleanup(void) { … } module_init(…) …; module_exit(ppp_mppe_cleanup);
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