From 17238967454f8db9ad652b2b143e1c6cdcafb102 Mon Sep 17 00:00:00 2001
From: acoul <acoul@3c298f89-4303-0410-b956-a3cf2f4a3e73>
Date: Tue, 16 Nov 2010 13:42:21 +0000
Subject: linux/generic: add kernel mppc/mppe for 2.6.37.
http://yablochkin.net.ru/mppc/ (not enabled by default)
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@24014 3c298f89-4303-0410-b956-a3cf2f4a3e73
---
package/kernel/modules/netsupport.mk | 4 +-
target/linux/generic/config-2.6.37 | 1 +
.../patches-2.6.37/251-mppe_mppc_2_6_36.patch | 1744 ++++++++++++++++++++
3 files changed, 1747 insertions(+), 2 deletions(-)
create mode 100644 target/linux/generic/patches-2.6.37/251-mppe_mppc_2_6_36.patch
diff --git a/package/kernel/modules/netsupport.mk b/package/kernel/modules/netsupport.mk
index 1baba4b5b..06adfddb6 100644
--- a/package/kernel/modules/netsupport.mk
+++ b/package/kernel/modules/netsupport.mk
@@ -511,8 +511,8 @@ define KernelPackage/mppe
KCONFIG:= \
CONFIG_PPP_MPPE_MPPC \
CONFIG_PPP_MPPE
- FILES:=$(LINUX_DIR)/drivers/net/ppp_mppe.ko
- AUTOLOAD:=$(call AutoLoad,31,ppp_mppe)
+ FILES:=$(LINUX_DIR)/drivers/net/ppp_mppe*.ko
+ AUTOLOAD:=$(call AutoLoad,31,ppp_mppe ppp_mppe_mppc)
endef
define KernelPackage/mppe/description
diff --git a/target/linux/generic/config-2.6.37 b/target/linux/generic/config-2.6.37
index c44f0ff14..2366e9578 100644
--- a/target/linux/generic/config-2.6.37
+++ b/target/linux/generic/config-2.6.37
@@ -1820,6 +1820,7 @@ CONFIG_PPC_4K_PAGES=y
# CONFIG_PPP_DEFLATE is not set
CONFIG_PPP_FILTER=y
# CONFIG_PPP_MPPE is not set
+# CONFIG_PPP_MPPE_MPPC is not set
CONFIG_PPP_MULTILINK=y
# CONFIG_PPP_SYNC_TTY is not set
# CONFIG_PPS is not set
diff --git a/target/linux/generic/patches-2.6.37/251-mppe_mppc_2_6_36.patch b/target/linux/generic/patches-2.6.37/251-mppe_mppc_2_6_36.patch
new file mode 100644
index 000000000..6deca35f1
--- /dev/null
+++ b/target/linux/generic/patches-2.6.37/251-mppe_mppc_2_6_36.patch
@@ -0,0 +1,1744 @@
+--- a/crypto/api.c
++++ b/crypto/api.c
+@@ -602,5 +602,20 @@ int crypto_has_alg(const char *name, u32
+ }
+ EXPORT_SYMBOL_GPL(crypto_has_alg);
+
++int crypto_alg_available(const char *name, u32 flags)
++{
++ int ret = 0;
++ struct crypto_alg *alg = crypto_alg_mod_lookup(name, 0,
++ CRYPTO_ALG_ASYNC);
++
++ if (!IS_ERR(alg)) {
++ crypto_mod_put(alg);
++ ret = 1;
++ }
++
++ return ret;
++}
++EXPORT_SYMBOL_GPL(crypto_alg_available);
++
+ MODULE_DESCRIPTION("Cryptographic core API");
+ MODULE_LICENSE("GPL");
+--- a/drivers/net/Kconfig
++++ b/drivers/net/Kconfig
+@@ -3349,19 +3349,31 @@ config PPP_BSDCOMP
+ module; it is called bsd_comp and will show up in the directory
+ modules once you have said "make modules". If unsure, say N.
+
+-config PPP_MPPE
+- tristate "PPP MPPE compression (encryption) (EXPERIMENTAL)"
+- depends on PPP && EXPERIMENTAL
+- select CRYPTO
+- select CRYPTO_SHA1
+- select CRYPTO_ARC4
+- select CRYPTO_ECB
+- ---help---
+- Support for the MPPE Encryption protocol, as employed by the
+- Microsoft Point-to-Point Tunneling Protocol.
++config PPP_MPPE_MPPC
++ tristate "Microsoft PPP compression/encryption (MPPC/MPPE)"
++ depends on PPP
++ select CRYPTO_SHA1
++ select CRYPTO_ARC4
++ ---help---
++ Support for the Microsoft Point-To-Point Compression (RFC2118) and
++ Microsoft Point-To-Point Encryption (RFC3078). These protocols are
++ supported by Microsoft Windows and wide range of "hardware" access
++ servers. MPPE is common protocol in Virtual Private Networks. According
++ to RFC3078, MPPE supports 40, 56 and 128-bit key lengths. Depending on
++ PPP daemon configuration on both ends of the link, following scenarios
++ are possible:
++ - only compression (MPPC) is used,
++ - only encryption (MPPE) is used,
++ - compression and encryption (MPPC+MPPE) are used.
+
+- See http://pptpclient.sourceforge.net/ for information on
+- configuring PPTP clients and servers to utilize this method.
++ Please note that Hi/Fn (http://www.hifn.com) holds patent on MPPC so
++ you should check if this patent is valid in your country in order to
++ avoid legal problems.
++
++ For more information please visit http://mppe-mppc.alphacron.de
++
++ To compile this driver as a module, choose M here. The module will
++ be called ppp_mppe_mppc.ko.
+
+ config PPPOE
+ tristate "PPP over Ethernet (EXPERIMENTAL)"
+--- a/drivers/net/Makefile
++++ b/drivers/net/Makefile
+@@ -162,7 +162,7 @@ obj-$(CONFIG_PPP_ASYNC) += ppp_async.o
+ obj-$(CONFIG_PPP_SYNC_TTY) += ppp_synctty.o
+ obj-$(CONFIG_PPP_DEFLATE) += ppp_deflate.o
+ obj-$(CONFIG_PPP_BSDCOMP) += bsd_comp.o
+-obj-$(CONFIG_PPP_MPPE) += ppp_mppe.o
++obj-$(CONFIG_PPP_MPPE_MPPC) += ppp_mppe_mppc.o
+ obj-$(CONFIG_PPPOE) += pppox.o pppoe.o
+ obj-$(CONFIG_PPPOL2TP) += pppox.o
+ obj-$(CONFIG_PPTP) += pppox.o pptp.o
+--- a/drivers/net/ppp_generic.c
++++ b/drivers/net/ppp_generic.c
+@@ -41,6 +41,7 @@
+ #include <linux/ip.h>
+ #include <linux/tcp.h>
+ #include <linux/spinlock.h>
++#include <linux/smp_lock.h>
+ #include <linux/rwsem.h>
+ #include <linux/stddef.h>
+ #include <linux/device.h>
+@@ -87,10 +88,11 @@ struct ppp_file {
+ int dead; /* unit/channel has been shut down */
+ };
+
+-#define PF_TO_X(pf, X) container_of(pf, X, file)
++#define PF_TO_X(pf, X) ((X *)((char *)(pf) - offsetof(X, file)))
+
+ #define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
+ #define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
++#define ROUNDUP(n, x) (((n) + (x) - 1) / (x))
+
+ /*
+ * Data structure describing one ppp unit.
+@@ -106,6 +108,7 @@ struct ppp {
+ spinlock_t rlock; /* lock for receive side 58 */
+ spinlock_t wlock; /* lock for transmit side 5c */
+ int mru; /* max receive unit 60 */
++ int mru_alloc; /* MAX(1500,MRU) for dev_alloc_skb() */
+ unsigned int flags; /* control bits 64 */
+ unsigned int xstate; /* transmit state bits 68 */
+ unsigned int rstate; /* receive state bits 6c */
+@@ -139,14 +142,13 @@ struct ppp {
+
+ /*
+ * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
+- * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
+- * SC_MUST_COMP
++ * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP.
+ * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
+ * Bits in xstate: SC_COMP_RUN
+ */
+ #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
+ |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
+- |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
++ |SC_COMP_TCP|SC_REJ_COMP_TCP)
+
+ /*
+ * Private data structure for each channel.
+@@ -639,7 +641,9 @@ static long ppp_ioctl(struct file *file,
+ case PPPIOCSMRU:
+ if (get_user(val, p))
+ break;
+- ppp->mru = val;
++ ppp->mru_alloc = ppp->mru = val;
++ if (ppp->mru_alloc < PPP_MRU)
++ ppp->mru_alloc = PPP_MRU; /* increase for broken peers */
+ err = 0;
+ break;
+
+@@ -1066,56 +1070,6 @@ ppp_xmit_process(struct ppp *ppp)
+ ppp_xmit_unlock(ppp);
+ }
+
+-static inline struct sk_buff *
+-pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
+-{
+- struct sk_buff *new_skb;
+- int len;
+- int new_skb_size = ppp->dev->mtu +
+- ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
+- int compressor_skb_size = ppp->dev->mtu +
+- ppp->xcomp->comp_extra + PPP_HDRLEN;
+- new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
+- if (!new_skb) {
+- if (net_ratelimit())
+- printk(KERN_ERR "PPP: no memory (comp pkt)\n");
+- return NULL;
+- }
+- if (ppp->dev->hard_header_len > PPP_HDRLEN)
+- skb_reserve(new_skb,
+- ppp->dev->hard_header_len - PPP_HDRLEN);
+-
+- /* compressor still expects A/C bytes in hdr */
+- len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
+- new_skb->data, skb->len + 2,
+- compressor_skb_size);
+- if (len > 0 && (ppp->flags & SC_CCP_UP)) {
+- kfree_skb(skb);
+- skb = new_skb;
+- skb_put(skb, len);
+- skb_pull(skb, 2); /* pull off A/C bytes */
+- } else if (len == 0) {
+- /* didn't compress, or CCP not up yet */
+- kfree_skb(new_skb);
+- new_skb = skb;
+- } else {
+- /*
+- * (len < 0)
+- * MPPE requires that we do not send unencrypted
+- * frames. The compressor will return -1 if we
+- * should drop the frame. We cannot simply test
+- * the compress_proto because MPPE and MPPC share
+- * the same number.
+- */
+- if (net_ratelimit())
+- printk(KERN_ERR "ppp: compressor dropped pkt\n");
+- kfree_skb(skb);
+- kfree_skb(new_skb);
+- new_skb = NULL;
+- }
+- return new_skb;
+-}
+-
+ /*
+ * Compress and send a frame.
+ * The caller should have locked the xmit path,
+@@ -1196,20 +1150,62 @@ ppp_send_frame(struct ppp *ppp, struct s
+ case PPP_CCP:
+ /* peek at outbound CCP frames */
+ ppp_ccp_peek(ppp, skb, 0);
++ if (CCP_CODE(skb->data+2) == CCP_RESETACK
++ && (ppp->xcomp->compress_proto == CI_MPPE
++ || ppp->xcomp->compress_proto == CI_LZS)) {
++ --ppp->dev->stats.tx_packets;
++ ppp->dev->stats.tx_bytes -= skb->len - 2;
++ kfree_skb(skb);
++ return;
++ }
+ break;
+ }
+
+ /* try to do packet compression */
+ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
+ proto != PPP_LCP && proto != PPP_CCP) {
+- if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
+- if (net_ratelimit())
+- printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
++ int comp_ovhd = 0;
++ /*
++ * because of possible data expansion when MPPC or LZS
++ * is used, allocate compressor's buffer 12.5% bigger
++ * than MTU
++ */
++ if (ppp->xcomp->compress_proto == CI_MPPE)
++ comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + MPPE_OVHD;
++ else if (ppp->xcomp->compress_proto == CI_LZS)
++ comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + LZS_OVHD;
++ new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len
++ + comp_ovhd, GFP_ATOMIC);
++ if (new_skb == 0) {
++ printk(KERN_ERR "PPP: no memory (comp pkt)\n");
+ goto drop;
+ }
+- skb = pad_compress_skb(ppp, skb);
+- if (!skb)
++ if (ppp->dev->hard_header_len > PPP_HDRLEN)
++ skb_reserve(new_skb,
++ ppp->dev->hard_header_len - PPP_HDRLEN);
++
++ /* compressor still expects A/C bytes in hdr */
++ len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
++ new_skb->data, skb->len + 2,
++ ppp->dev->mtu + PPP_HDRLEN);
++ if (len > 0 && (ppp->flags & SC_CCP_UP)) {
++ kfree_skb(skb);
++ skb = new_skb;
++ skb_put(skb, len);
++ skb_pull(skb, 2); /* pull off A/C bytes */
++ } else if (len == 0) {
++ /*
++ * (len < 0)
++ * MPPE requires that we do not send unencrypted
++ * frames. The compressor will return -1 if we
++ * should drop the frame. We cannot simply test
++ * the compress_proto because MPPE and MPPC share
++ * the same number.
++ */
++ printk(KERN_ERR "ppp: compressor dropped pkt\n");
++ kfree_skb(new_skb);
+ goto drop;
++ }
+ }
+
+ /*
+@@ -1670,9 +1666,6 @@ ppp_receive_nonmp_frame(struct ppp *ppp,
+ (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
+ skb = ppp_decompress_frame(ppp, skb);
+
+- if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
+- goto err;
+-
+ proto = PPP_PROTO(skb);
+ switch (proto) {
+ case PPP_VJC_COMP:
+@@ -1852,7 +1845,14 @@ ppp_decompress_frame(struct ppp *ppp, st
+ return skb;
+
+ err:
+- ppp->rstate |= SC_DC_ERROR;
++ if (ppp->rcomp->compress_proto != CI_MPPE
++ && ppp->rcomp->compress_proto != CI_LZS) {
++ /*
++ * If decompression protocol isn't MPPE/MPPC or LZS, we set
++ * SC_DC_ERROR flag and wait for CCP_RESETACK
++ */
++ ppp->rstate |= SC_DC_ERROR;
++ }
+ ppp_receive_error(ppp);
+ return skb;
+ }
+@@ -2566,6 +2566,7 @@ ppp_create_interface(struct net *net, in
+ ppp = netdev_priv(dev);
+ ppp->dev = dev;
+ ppp->mru = PPP_MRU;
++ ppp->mru_alloc = PPP_MRU;
+ init_ppp_file(&ppp->file, INTERFACE);
+ ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
+ for (i = 0; i < NUM_NP; ++i)
+--- /dev/null
++++ b/drivers/net/ppp_mppe_mppc.c
+@@ -0,0 +1,1308 @@
++/*
++ * ppp_mppe_mppc.c - MPPC/MPPE "compressor/decompressor" module.
++ *
++ * Copyright (c) 1994 �rp�d Magos�nyi <mag@bunuel.tii.matav.hu>
++ * Copyright (c) 1999 Tim Hockin, Cobalt Networks Inc. <thockin@cobaltnet.com>
++ * Copyright (c) 2002-2004 Jan Dubiec <jdx@slackware.pl>
++ *
++ * 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.
++ *
++ * The code is based on MPPE kernel module written by �rp�d Magos�nyi and
++ * Tim Hockin which can be found on http://planetmirror.com/pub/mppe/.
++ * I have added MPPC and 56 bit session keys support in MPPE.
++ *
++ * WARNING! Although this is open source code, its usage in some countries
++ * (in particular in the USA) may violate Stac Inc. patent for MPPC.
++ *
++ * ==FILEVERSION 20041123==
++ *
++ */
++
++#include <linux/init.h>
++#include <linux/module.h>
++#include <linux/mm.h>
++#include <linux/slab.h>
++#include <asm/scatterlist.h>
++#include <linux/vmalloc.h>
++#include <linux/crypto.h>
++
++#include <linux/ppp_defs.h>
++#include <linux/ppp-comp.h>
++
++/*
++ * State for a mppc/mppe "(de)compressor".
++ */
++struct ppp_mppe_state {
++ struct crypto_tfm *arc4_tfm;
++ struct crypto_hash *sha1_tfm;
++ u8 *sha1_digest;
++ u8 master_key[MPPE_MAX_KEY_LEN];
++ u8 session_key[MPPE_MAX_KEY_LEN];
++ u8 mppc; /* do we use compression (MPPC)? */
++ u8 mppe; /* do we use encryption (MPPE)? */
++ u8 keylen; /* key length in bytes */
++ u8 bitkeylen; /* key length in bits */
++ u16 ccount; /* coherency counter */
++ u16 bits; /* MPPC/MPPE control bits */
++ u8 stateless; /* do we use stateless mode? */
++ u8 nextflushed; /* set A bit in the next outgoing packet;
++ used only by compressor*/
++ u8 flushexpected; /* drop packets until A bit is received;
++ used only by decompressor*/
++ u8 *hist; /* MPPC history */
++ u16 *hash; /* Hash table; used only by compressor */
++ u16 histptr; /* history "cursor" */
++ int unit;
++ int debug;
++ int mru;
++ struct compstat stats;
++};
++
++#define MPPE_HIST_LEN 8192 /* MPPC history size */
++#define MPPE_MAX_CCOUNT 0x0FFF /* max. coherency counter value */
++
++#define MPPE_BIT_FLUSHED 0x80 /* bit A */
++#define MPPE_BIT_RESET 0x40 /* bit B */
++#define MPPE_BIT_COMP 0x20 /* bit C */
++#define MPPE_BIT_ENCRYPTED 0x10 /* bit D */
++
++#define MPPE_SALT0 0xD1 /* values used in MPPE key derivation */
++#define MPPE_SALT1 0x26 /* according to RFC3079 */
++#define MPPE_SALT2 0x9E
++
++#define MPPE_CCOUNT(x) ((((x)[4] & 0x0f) << 8) + (x)[5])
++#define MPPE_BITS(x) ((x)[4] & 0xf0)
++#define MPPE_CTRLHI(x) ((((x)->ccount & 0xf00)>>8)|((x)->bits))
++#define MPPE_CTRLLO(x) ((x)->ccount & 0xff)
++
++/*
++ * 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. It is done
++ * in mppe_module_init(). This has been pointed out on 30th July 2004 by Oleg
++ * Makarenko on pptpclient-devel mailing list.
++ */
++#define SHA1_PAD_SIZE 40
++struct sha_pad {
++ unsigned char sha_pad1[SHA1_PAD_SIZE];
++ unsigned char sha_pad2[SHA1_PAD_SIZE];
++};
++static struct sha_pad *sha_pad;
++
++static unsigned int
++setup_sg(struct scatterlist *sg, const void *address, unsigned int length)
++{
++ sg[0].page_link = virt_to_page(address);
++ sg[0].offset = offset_in_page(address);
++ sg[0].length = length;
++ return length;
++}
++
++static inline void
++arc4_setkey(struct ppp_mppe_state *state, const unsigned char *key,
++ const unsigned int keylen)
++{
++ crypto_cipher_setkey(state->arc4_tfm, key, keylen);
++}
++
++static inline void
++arc4_encrypt(struct ppp_mppe_state *state, const unsigned char *in,
++ const unsigned int len, unsigned char *out)
++{
++ int i;
++ for (i = 0; i < len; i++)
++ {
++ crypto_cipher_encrypt_one(state->arc4_tfm, out+i, in+i);
++ }
++}
++
++
++#define arc4_decrypt arc4_encrypt
++
++/*
++ * 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, unsigned char *interim_key)
++{
++ struct hash_desc desc;
++ struct scatterlist sg[4];
++ unsigned int nbytes;
++
++
++ nbytes = setup_sg(&sg[0], state->master_key, state->keylen);
++ nbytes += setup_sg(&sg[1], sha_pad->sha_pad1,
++ sizeof(sha_pad->sha_pad1));
++ nbytes += setup_sg(&sg[2], state->session_key, state->keylen);
++ nbytes += setup_sg(&sg[3], sha_pad->sha_pad2,
++ sizeof(sha_pad->sha_pad2));
++
++ desc.tfm = state->sha1_tfm;
++ desc.flags = 0;
++
++ crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
++ memcpy(interim_key, state->sha1_digest, state->keylen);
++}
++
++static void
++mppe_change_key(struct ppp_mppe_state *state, int initialize)
++{
++ unsigned char interim_key[MPPE_MAX_KEY_LEN];
++
++ get_new_key_from_sha(state, interim_key);
++ if (initialize) {
++ memcpy(state->session_key, interim_key, state->keylen);
++ } else {
++ arc4_setkey(state, interim_key, state->keylen);
++ arc4_encrypt(state, interim_key, state->keylen, state->session_key);
++ }
++ if (state->keylen == 8) {
++ if (state->bitkeylen == 40) {
++ state->session_key[0] = MPPE_SALT0;
++ state->session_key[1] = MPPE_SALT1;
++ state->session_key[2] = MPPE_SALT2;
++ } else {
++ state->session_key[0] = MPPE_SALT0;
++ }
++ }
++ arc4_setkey(state, state->session_key, state->keylen);
++}
++
++/* increase 12-bit coherency counter */
++static inline void
++mppe_increase_ccount(struct ppp_mppe_state *state)
++{
++ state->ccount = (state->ccount + 1) & MPPE_MAX_CCOUNT;
++ if (state->mppe) {
++ if (state->stateless) {
++ mppe_change_key(state, 0);
++ state->nextflushed = 1;
++ } else {
++ if ((state->ccount & 0xff) == 0xff) {
++ mppe_change_key(state, 0);
++ }
++ }
++ }
++}
++
++/* allocate space for a MPPE/MPPC (de)compressor. */
++/* comp != 0 -> init compressor */
++/* comp = 0 -> init decompressor */
++static void *
++mppe_alloc(unsigned char *options, int opt_len, int comp)
++{
++ struct ppp_mppe_state *state;
++ unsigned int digestsize;
++ u8* fname;
++
++ fname = comp ? "mppe_comp_alloc" : "mppe_decomp_alloc";
++
++ /*
++ * Hack warning - additionally to the standard MPPC/MPPE configuration
++ * options, pppd passes to the (de)copressor 8 or 16 byte session key.
++ * Therefore options[1] contains MPPC/MPPE configuration option length
++ * (CILEN_MPPE = 6), but the real options length, depending on the key
++ * length, is 6+8 or 6+16.
++ */
++ if (opt_len < CILEN_MPPE) {
++ printk(KERN_WARNING "%s: wrong options length: %u\n", fname, opt_len);
++ return NULL;
++ }
++
++ if (options[0] != CI_MPPE || options[1] != CILEN_MPPE ||
++ (options[2] & ~MPPE_STATELESS) != 0 ||
++ options[3] != 0 || options[4] != 0 ||
++ (options[5] & ~(MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) != 0 ||
++ (options[5] & (MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) == 0) {
++ printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, "
++ "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname, options[0],
++ options[1], options[2], options[3], options[4], options[5]);
++ return NULL;
++ }
++
++ state = (struct ppp_mppe_state *)kmalloc(sizeof(*state), GFP_KERNEL);
++ if (state == NULL) {
++ printk(KERN_ERR "%s: cannot allocate space for %scompressor\n", fname,
++ comp ? "" : "de");
++ return NULL;
++ }
++ memset(state, 0, sizeof(struct ppp_mppe_state));
++
++ state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */
++ state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT |
++ MPPE_40BIT); /* Do we use MPPE? */
++
++ if (state->mppc) {
++ /* allocate MPPC history */
++ state->hist = (u8*)vmalloc(2*MPPE_HIST_LEN*sizeof(u8));
++ if (state->hist == NULL) {
++ kfree(state);
++ printk(KERN_ERR "%s: cannot allocate space for MPPC history\n",
++ fname);
++ return NULL;
++ }
++
++ /* allocate hashtable for MPPC compressor */
++ if (comp) {
++ state->hash = (u16*)vmalloc(MPPE_HIST_LEN*sizeof(u16));
++ if (state->hash == NULL) {
++ vfree(state->hist);
++ kfree(state);
++ printk(KERN_ERR "%s: cannot allocate space for MPPC history\n",
++ fname);
++ return NULL;
++ }
++ }
++ }
++
++ if (state->mppe) { /* specific for MPPE */
++ /* Load ARC4 algorithm */
++ state->arc4_tfm = crypto_alloc_base("arc4", 0, 0);
++ if (state->arc4_tfm == NULL) {
++ if (state->mppc) {
++ vfree(state->hash);
++ if (comp)
++ vfree(state->hist);
++ }
++ kfree(state);
++ printk(KERN_ERR "%s: cannot load ARC4 module\n", fname);
++ return NULL;
++ }
++
++ /* Load SHA1 algorithm */
++ state->sha1_tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
++ if (state->sha1_tfm == NULL) {
++ crypto_free_tfm(state->arc4_tfm);
++ if (state->mppc) {
++ vfree(state->hash);
++ if (comp)
++ vfree(state->hist);
++ }
++ kfree(state);
++ printk(KERN_ERR "%s: cannot load SHA1 module\n", fname);
++ return NULL;
++ }
++
++ digestsize = crypto_hash_digestsize(state->sha1_tfm);
++ if (digestsize < MPPE_MAX_KEY_LEN) {
++ crypto_free_hash(state->sha1_tfm);
++ crypto_free_tfm(state->arc4_tfm);
++ if (state->mppc) {
++ vfree(state->hash);
++ if (comp)
++ vfree(state->hist);
++ }
++ kfree(state);
++ printk(KERN_ERR "%s: CryptoAPI SHA1 digest size too small\n", fname);
++ }
++
++ state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
++ if (!state->sha1_digest) {
++ crypto_free_hash(state->sha1_tfm);
++ crypto_free_tfm(state->arc4_tfm);
++ if (state->mppc) {
++ vfree(state->hash);
++ if (comp)
++ vfree(state->hist);
++ }
++ kfree(state);
++ printk(KERN_ERR "%s: cannot allocate space for SHA1 digest\n", fname);
++ }
++
++ memcpy(state->master_key, options+CILEN_MPPE, MPPE_MAX_KEY_LEN);
++ memcpy(state->session_key, state->master_key, MPPE_MAX_KEY_LEN);
++ /* initial key generation is done in mppe_init() */
++ }
++
++ return (void *) state;
++}
++
++static void *
++mppe_comp_alloc(unsigned char *options, int opt_len)
++{
++ return mppe_alloc(options, opt_len, 1);
++}
++
++static void *
++mppe_decomp_alloc(unsigned char *options, int opt_len)
++{
++ return mppe_alloc(options, opt_len, 0);
++}
++
++/* cleanup the (de)compressor */
++static void
++mppe_comp_free(void *arg)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
++
++ if (state != NULL) {
++ if (state->mppe) {
++ if (state->sha1_digest != NULL)
++ kfree(state->sha1_digest);
++ if (state->sha1_tfm != NULL)
++ crypto_free_hash(state->sha1_tfm);
++ if (state->arc4_tfm != NULL)
++ crypto_free_tfm(state->arc4_tfm);
++ }
++ if (state->hist != NULL)
++ vfree(state->hist);
++ if (state->hash != NULL)
++ vfree(state->hash);
++ kfree(state);
++ }
++}
++
++/* init MPPC/MPPE (de)compresor */
++/* comp != 0 -> init compressor */
++/* comp = 0 -> init decompressor */
++static int
++mppe_init(void *arg, unsigned char *options, int opt_len, int unit,
++ int hdrlen, int mru, int debug, int comp)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
++ u8* fname;
++
++ fname = comp ? "mppe_comp_init" : "mppe_decomp_init";
++
++ if (opt_len < CILEN_MPPE) {
++ if (debug)
++ printk(KERN_WARNING "%s: wrong options length: %u\n",
++ fname, opt_len);
++ return 0;
++ }
++
++ if (options[0] != CI_MPPE || options[1] != CILEN_MPPE ||
++ (options[2] & ~MPPE_STATELESS) != 0 ||
++ options[3] != 0 || options[4] != 0 ||
++ (options[5] & ~(MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) != 0 ||
++ (options[5] & (MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) == 0) {
++ if (debug)
++ printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, "
++ "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname,
++ options[0], options[1], options[2], options[3], options[4],
++ options[5]);
++ return 0;
++ }
++
++ if ((options[5] & ~MPPE_MPPC) != MPPE_128BIT &&
++ (options[5] & ~MPPE_MPPC) != MPPE_56BIT &&
++ (options[5] & ~MPPE_MPPC) != MPPE_40BIT &&
++ (options[5] & MPPE_MPPC) != MPPE_MPPC) {
++ if (debug)
++ printk(KERN_WARNING "%s: don't know what to do: o[5]=%02x\n",
++ fname, options[5]);
++ return 0;
++ }
++
++ state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */
++ state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT |
++ MPPE_40BIT); /* Do we use MPPE? */
++ state->stateless = options[2] & MPPE_STATELESS; /* Do we use stateless mode? */
++
++ switch (state->mppe) {
++ case MPPE_40BIT: /* 40 bit key */
++ state->keylen = 8;
++ state->bitkeylen = 40;
++ break;
++ case MPPE_56BIT: /* 56 bit key */
++ state->keylen = 8;
++ state->bitkeylen = 56;
++ break;
++ case MPPE_128BIT: /* 128 bit key */
++ state->keylen = 16;
++ state->bitkeylen = 128;
++ break;
++ default:
++ state->keylen = 0;
++ state->bitkeylen = 0;
++ }
++
++ state->ccount = MPPE_MAX_CCOUNT;
++ state->bits = 0;
++ state->unit = unit;
++ state->debug = debug;
++ state->histptr = MPPE_HIST_LEN;
++ if (state->mppc) { /* reset history if MPPC was negotiated */
++ memset(state->hist, 0, 2*MPPE_HIST_LEN*sizeof(u8));
++ }
++
++ if (state->mppe) { /* generate initial session keys */
++ mppe_change_key(state, 1);
++ }
++
++ if (comp) { /* specific for compressor */
++ state->nextflushed = 1;
++ } else { /* specific for decompressor */
++ state->mru = mru;
++ state->flushexpected = 1;
++ }
++
++ return 1;
++}
++
++static int
++mppe_comp_init(void *arg, unsigned char *options, int opt_len, int unit,
++ int hdrlen, int debug)
++{
++ return mppe_init(arg, options, opt_len, unit, hdrlen, 0, debug, 1);
++}
++
++
++static int
++mppe_decomp_init(void *arg, unsigned char *options, int opt_len, int unit,
++ int hdrlen, int mru, int debug)
++{
++ return mppe_init(arg, options, opt_len, unit, hdrlen, mru, debug, 0);
++}
++
++static void
++mppe_comp_reset(void *arg)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
++
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: resetting MPPC/MPPE compressor\n",
++ __FUNCTION__, state->unit);
++
++ state->nextflushed = 1;
++ if (state->mppe)
++ arc4_setkey(state, state->session_key, state->keylen);
++}
++
++static void
++mppe_decomp_reset(void *arg)
++{
++ /* When MPPC/MPPE is in use, we shouldn't receive any CCP Reset-Ack.
++ But when we receive such a packet, we just ignore it. */
++ return;
++}
++
++static void
++mppe_stats(void *arg, struct compstat *stats)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
++
++ *stats = state->stats;
++}
++
++/***************************/
++/**** Compression stuff ****/
++/***************************/
++/* inserts 1 to 8 bits into the output buffer */
++static inline void putbits8(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
++{
++ buf += *i;
++ if (*l >= n) {
++ *l = (*l) - n;
++ val <<= *l;
++ *buf = *buf | (val & 0xff);
++ if (*l == 0) {
++ *l = 8;
++ (*i)++;
++ *(++buf) = 0;
++ }
++ } else {
++ (*i)++;
++ *l = 8 - n + (*l);
++ val <<= *l;
++ *buf = *buf | ((val >> 8) & 0xff);
++ *(++buf) = val & 0xff;
++ }
++}
++
++/* inserts 9 to 16 bits into the output buffer */
++static inline void putbits16(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
++{
++ buf += *i;
++ if (*l >= n - 8) {
++ (*i)++;
++ *l = 8 - n + (*l);
++ val <<= *l;
++ *buf = *buf | ((val >> 8) & 0xff);
++ *(++buf) = val & 0xff;
++ if (*l == 0) {
++ *l = 8;
++ (*i)++;
++ *(++buf) = 0;
++ }
++ } else {
++ (*i)++; (*i)++;
++ *l = 16 - n + (*l);
++ val <<= *l;
++ *buf = *buf | ((val >> 16) & 0xff);
++ *(++buf) = (val >> 8) & 0xff;
++ *(++buf) = val & 0xff;
++ }
++}
++
++/* inserts 17 to 24 bits into the output buffer */
++static inline void putbits24(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
++{
++ buf += *i;
++ if (*l >= n - 16) {
++ (*i)++; (*i)++;
++ *l = 16 - n + (*l);
++ val <<= *l;
++ *buf = *buf | ((val >> 16) & 0xff);
++ *(++buf) = (val >> 8) & 0xff;
++ *(++buf) = val & 0xff;
++ if (*l == 0) {
++ *l = 8;
++ (*i)++;
++ *(++buf) = 0;
++ }
++ } else {
++ (*i)++; (*i)++; (*i)++;
++ *l = 24 - n + (*l);
++ val <<= *l;
++ *buf = *buf | ((val >> 24) & 0xff);
++ *(++buf) = (val >> 16) & 0xff;
++ *(++buf) = (val >> 8) & 0xff;
++ *(++buf) = val & 0xff;
++ }
++}
++
++static int
++mppc_compress(struct ppp_mppe_state *state, unsigned char *ibuf,
++ unsigned char *obuf, int isize, int osize)
++{
++ u32 olen, off, len, idx, i, l;
++ u8 *hist, *sbuf, *p, *q, *r, *s;
++
++ /*
++ At this point, to avoid possible buffer overflow caused by packet
++ expansion during/after compression, we should make sure that
++ osize >= (((isize*9)/8)+1)+2, but we don't do that because in
++ ppp_generic.c we simply allocate bigger obuf.
++
++ Maximum MPPC packet expansion is 12.5%. This is the worst case when
++ all octets in the input buffer are >= 0x80 and we cannot find any
++ repeated tokens. Additionally we have to reserve 2 bytes for MPPE/MPPC
++ status bits and coherency counter.
++ */
++
++ hist = state->hist + MPPE_HIST_LEN;
++ /* check if there is enough room at the end of the history */
++ if (state->histptr + isize >= 2*MPPE_HIST_LEN) {
++ state->bits |= MPPE_BIT_RESET;
++ state->histptr = MPPE_HIST_LEN;
++ memcpy(state->hist, hist, MPPE_HIST_LEN);
++ }
++ /* add packet to the history; isize must be <= MPPE_HIST_LEN */
++ sbuf = state->hist + state->histptr;
++ memcpy(sbuf, ibuf, isize);
++ state->histptr += isize;
++
++ /* compress data */
++ r = sbuf + isize;
++ *obuf = olen = i = 0;
++ l = 8;
++ while (i < isize - 2) {
++ s = q = sbuf + i;
++ idx = ((40543*((((s[0]<<4)^s[1])<<4)^s[2]))>>4) & 0x1fff;
++ p = hist + state->hash[idx];
++ state->hash[idx] = (u16) (s - hist);
++ off = s - p;
++ if (off > MPPE_HIST_LEN - 1 || off < 1 || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++) {
++ /* no match found; encode literal byte */
++ if (ibuf[i] < 0x80) { /* literal byte < 0x80 */
++ putbits8(obuf, (u32) ibuf[i], 8, &olen, &l);
++ } else { /* literal byte >= 0x80 */
++ putbits16(obuf, (u32) (0x100|(ibuf[i]&0x7f)), 9, &olen, &l);
++ }
++ ++i;
++ continue;
++ }
++ if (r - q >= 64) {
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
++ *p++ != *s++;
++ if (s - q == 64) {
++ p--; s--;
++ while((*p++ == *s++) && (s < r) && (p < q));
++ }
++ } else {
++ while((*p++ == *s++) && (s < r) && (p < q));
++ }
++ len = s - q - 1;
++ i += len;
++
++ /* at least 3 character match found; code data */
++ /* encode offset */
++ if (off < 64) { /* 10-bit offset; 0 <= offset < 64 */
++ putbits16(obuf, 0x3c0|off, 10, &olen, &l);
++ } else if (off < 320) { /* 12-bit offset; 64 <= offset < 320 */
++ putbits16(obuf, 0xe00|(off-64), 12, &olen, &l);
++ } else if (off < 8192) { /* 16-bit offset; 320 <= offset < 8192 */
++ putbits16(obuf, 0xc000|(off-320), 16, &olen, &l);
++ } else {
++ /* This shouldn't happen; we return 0 what means "packet expands",
++ and we send packet uncompressed. */
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: wrong offset value: %d\n",
++ __FUNCTION__, state->unit, off);
++ return 0;
++ }
++ /* encode length of match */
++ if (len < 4) { /* length = 3 */
++ putbits8(obuf, 0, 1, &olen, &l);
++ } else if (len < 8) { /* 4 <= length < 8 */
++ putbits8(obuf, 0x08|(len&0x03), 4, &olen, &l);
++ } else if (len < 16) { /* 8 <= length < 16 */
++ putbits8(obuf, 0x30|(len&0x07), 6, &olen, &l);
++ } else if (len < 32) { /* 16 <= length < 32 */
++ putbits8(obuf, 0xe0|(len&0x0f), 8, &olen, &l);
++ } else if (len < 64) { /* 32 <= length < 64 */
++ putbits16(obuf, 0x3c0|(len&0x1f), 10, &olen, &l);
++ } else if (len < 128) { /* 64 <= length < 128 */
++ putbits16(obuf, 0xf80|(len&0x3f), 12, &olen, &l);
++ } else if (len < 256) { /* 128 <= length < 256 */
++ putbits16(obuf, 0x3f00|(len&0x7f), 14, &olen, &l);
++ } else if (len < 512) { /* 256 <= length < 512 */
++ putbits16(obuf, 0xfe00|(len&0xff), 16, &olen, &l);
++ } else if (len < 1024) { /* 512 <= length < 1024 */
++ putbits24(obuf, 0x3fc00|(len&0x1ff), 18, &olen, &l);
++ } else if (len < 2048) { /* 1024 <= length < 2048 */
++ putbits24(obuf, 0xff800|(len&0x3ff), 20, &olen, &l);
++ } else if (len < 4096) { /* 2048 <= length < 4096 */
++ putbits24(obuf, 0x3ff000|(len&0x7ff), 22, &olen, &l);
++ } else if (len < 8192) { /* 4096 <= length < 8192 */
++ putbits24(obuf, 0xffe000|(len&0xfff), 24, &olen, &l);
++ } else {
++ /* This shouldn't happen; we return 0 what means "packet expands",
++ and send packet uncompressed. */
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: wrong length of match value: %d\n",
++ __FUNCTION__, state->unit, len);
++ return 0;
++ }
++ }
++
++ /* Add remaining octets to the output */
++ while(isize - i > 0) {
++ if (ibuf[i] < 0x80) { /* literal byte < 0x80 */
++ putbits8(obuf, (u32) ibuf[i++], 8, &olen, &l);
++ } else { /* literal byte >= 0x80 */
++ putbits16(obuf, (u32) (0x100|(ibuf[i++]&0x7f)), 9, &olen, &l);
++ }
++ }
++ /* Reset unused bits of the last output octet */
++ if ((l != 0) && (l != 8)) {
++ putbits8(obuf, 0, l, &olen, &l);
++ }
++
++ return (int) olen;
++}
++
++int
++mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
++ int isize, int osize)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
++ int proto, olen, complen, off;
++ unsigned char *wptr;
++
++ /* Check that the protocol is in the range we handle. */
++ proto = PPP_PROTOCOL(ibuf);
++ if (proto < 0x0021 || proto > 0x00fa)
++ return 0;
++
++ wptr = obuf;
++ /* Copy over the PPP header */
++ wptr[0] = PPP_ADDRESS(ibuf);
++ wptr[1] = PPP_CONTROL(ibuf);
++ wptr[2] = PPP_COMP >> 8;
++ wptr[3] = PPP_COMP;
++ wptr += PPP_HDRLEN + (MPPE_OVHD / 2); /* Leave two octets for MPPE/MPPC bits */
++
++ /*
++ * In ver. 0.99 protocol field was compressed. Deflate and BSD compress
++ * do PFC before actual compression, RCF2118 and RFC3078 are not precise
++ * on this topic so I decided to do PFC. Unfortunately this change caused
++ * incompatibility with older/other MPPE/MPPC modules. I have received
++ * a lot of complaints from unexperienced users so I have decided to revert
++ * to previous state, i.e. the protocol field is sent uncompressed now.
++ * Although this may be changed in the future.
++ *
++ * Receiving side (mppe_decompress()) still accepts packets with compressed
++ * and uncompressed protocol field so you shouldn't get "Unsupported protocol
++ * 0x2145 received" messages anymore.
++ */
++ //off = (proto > 0xff) ? 2 : 3; /* PFC - skip first protocol byte if 0 */
++ off = 2;
++
++ ibuf += off;
++
++ mppe_increase_ccount(state);
++
++ if (state->nextflushed) {
++ state->bits |= MPPE_BIT_FLUSHED;
++ state->nextflushed = 0;
++ if (state->mppe && !state->stateless) {
++ /*
++ * If this is the flag packet, the key has been already changed in
++ * mppe_increase_ccount() so we dont't do it once again.
++ */
++ if ((state->ccount & 0xff) != 0xff) {
++ arc4_setkey(state, state->session_key, state->keylen);
++ }
++ }
++ if (state->mppc) { /* reset history */
++ state->bits |= MPPE_BIT_RESET;
++ state->histptr = MPPE_HIST_LEN;
++ memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8));
++ }
++ }
++
++ if (state->mppc && !state->mppe) { /* Do only compression */
++ complen = mppc_compress(state, ibuf, wptr, isize - off,
++ osize - PPP_HDRLEN - (MPPE_OVHD / 2));
++ /*
++ * TODO: Implement an heuristics to handle packet expansion in a smart
++ * way. Now, when a packet expands, we send it as uncompressed and
++ * when next packet is sent we have to reset compressor's history.
++ * Maybe it would be better to send such packet as compressed in order
++ * to keep history's continuity.
++ */
++ if ((complen > isize) || (complen > osize - PPP_HDRLEN) ||
++ (complen == 0)) {
++ /* packet expands */
++ state->nextflushed = 1;
++ memcpy(wptr, ibuf, isize - off);
++ olen = isize - (off - 2) + MPPE_OVHD;
++ (state->stats).inc_bytes += olen;
++ (state->stats).inc_packets++;
++ } else {
++ state->bits |= MPPE_BIT_COMP;
++ olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2);
++ (state->stats).comp_bytes += olen;
++ (state->stats).comp_packets++;
++ }
++ } else { /* Do encryption with or without compression */
++ state->bits |= MPPE_BIT_ENCRYPTED;
++ if (!state->mppc && state->mppe) { /* Do only encryption */
++ /* read from ibuf, write to wptr, adjust for PPP_HDRLEN */
++ arc4_encrypt(state, ibuf, isize - off, wptr);
++ olen = isize - (off - 2) + MPPE_OVHD;
++ (state->stats).inc_bytes += olen;
++ (state->stats).inc_packets++;
++ } else { /* Do compression and then encryption - RFC3078 */
++ complen = mppc_compress(state, ibuf, wptr, isize - off,
++ osize - PPP_HDRLEN - (MPPE_OVHD / 2));
++ /*
++ * TODO: Implement an heuristics to handle packet expansion in a smart
++ * way. Now, when a packet expands, we send it as uncompressed and
++ * when next packet is sent we have to reset compressor's history.
++ * Maybe it would be good to send such packet as compressed in order
++ * to keep history's continuity.
++ */
++ if ((complen > isize) || (complen > osize - PPP_HDRLEN) ||
++ (complen == 0)) {
++ /* packet expands */
++ state->nextflushed = 1;
++ arc4_encrypt(state, ibuf, isize - off, wptr);
++ olen = isize - (off - 2) + MPPE_OVHD;
++ (state->stats).inc_bytes += olen;
++ (state->stats).inc_packets++;
++ } else {
++ state->bits |= MPPE_BIT_COMP;
++ /* Hack warning !!! RC4 implementation which we use does
++ encryption "in place" - it means that input and output
++ buffers can be *the same* memory area. Therefore we don't
++ need to use a temporary buffer. But be careful - other
++ implementations don't have to be so nice.
++ I used to use ibuf as temporary buffer here, but it led
++ packet sniffers into error. Thanks to Wilfried Weissmann
++ for pointing that. */
++ arc4_encrypt(state, wptr, complen, wptr);
++ olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2);
++ (state->stats).comp_bytes += olen;
++ (state->stats).comp_packets++;
++ }
++ }
++ }
++
++ /* write status bits and coherency counter into the output buffer */
++ wptr = obuf + PPP_HDRLEN;
++ wptr[0] = MPPE_CTRLHI(state);
++ wptr[1] = MPPE_CTRLLO(state);
++
++ state->bits = 0;
++
++ (state->stats).unc_bytes += isize;
++ (state->stats).unc_packets++;
++
++ return olen;
++}
++
++/***************************/
++/*** Decompression stuff ***/
++/***************************/
++static inline u32 getbits(const u8 *buf, const u32 n, u32 *i, u32 *l)
++{
++ static const u32 m[] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
++ u32 res, ol;
++
++ ol = *l;
++ if (*l >= n) {
++ *l = (*l) - n;
++ res = (buf[*i] & m[ol]) >> (*l);
++ if (*l == 0) {
++ *l = 8;
++ (*i)++;
++ }
++ } else {
++ *l = 8 - n + (*l);
++ res = (buf[(*i)++] & m[ol]) << 8;
++ res = (res | buf[*i]) >> (*l);
++ }
++
++ return res;
++}
++
++static inline u32 getbyte(const u8 *buf, const u32 i, const u32 l)
++{
++ if (l == 8) {
++ return buf[i];
++ } else {
++ return (((buf[i] << 8) | buf[i+1]) >> l) & 0xff;
++ }
++}
++
++static inline void lamecopy(u8 *dst, u8 *src, u32 len)
++{
++ while (len--)
++ *dst++ = *src++;
++}
++
++static int
++mppc_decompress(struct ppp_mppe_state *state, unsigned char *ibuf,
++ unsigned char *obuf, int isize, int osize)
++{
++ u32 olen, off, len, bits, val, sig, i, l;
++ u8 *history, *s;
++
++ history = state->hist + state->histptr;
++ olen = len = i = 0;
++ l = 8;
++ bits = isize * 8;
++ while (bits >= 8) {
++ val = getbyte(ibuf, i++, l);
++ if (val < 0x80) { /* literal byte < 0x80 */
++ if (state->histptr < 2*MPPE_HIST_LEN) {
++ /* copy uncompressed byte to the history */
++ (state->hist)[(state->histptr)++] = (u8) val;
++ } else {
++ /* buffer overflow; drop packet */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: trying to write outside history "
++ "buffer\n", __FUNCTION__, state->unit);
++ return DECOMP_ERROR;
++ }
++ olen++;
++ bits -= 8;
++ continue;
++ }
++
++ sig = val & 0xc0;
++ if (sig == 0x80) { /* literal byte >= 0x80 */
++ if (state->histptr < 2*MPPE_HIST_LEN) {
++ /* copy uncompressed byte to the history */
++ (state->hist)[(state->histptr)++] =
++ (u8) (0x80|((val&0x3f)<<1)|getbits(ibuf, 1 , &i ,&l));
++ } else {
++ /* buffer overflow; drop packet */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: trying to write outside history "
++ "buffer\n", __FUNCTION__, state->unit);
++ return DECOMP_ERROR;
++ }
++ olen++;
++ bits -= 9;
++ continue;
++ }
++
++ /* Not a literal byte so it must be an (offset,length) pair */
++ /* decode offset */
++ sig = val & 0xf0;
++ if (sig == 0xf0) { /* 10-bit offset; 0 <= offset < 64 */
++ off = (((val&0x0f)<<2)|getbits(ibuf, 2 , &i ,&l));
++ bits -= 10;
++ } else {
++ if (sig == 0xe0) { /* 12-bit offset; 64 <= offset < 320 */
++ off = ((((val&0x0f)<<4)|getbits(ibuf, 4 , &i ,&l))+64);
++ bits -= 12;
++ } else {
++ if ((sig&0xe0) == 0xc0) {/* 16-bit offset; 320 <= offset < 8192 */
++ off = ((((val&0x1f)<<8)|getbyte(ibuf, i++, l))+320);
++ bits -= 16;
++ if (off > MPPE_HIST_LEN - 1) {
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: too big offset value: %d\n",
++ __FUNCTION__, state->unit, off);
++ return DECOMP_ERROR;
++ }
++ } else { /* this shouldn't happen */
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: cannot decode offset value\n",
++ __FUNCTION__, state->unit);
++ return DECOMP_ERROR;
++ }
++ }
++ }
++ /* decode length of match */
++ val = getbyte(ibuf, i, l);
++ if ((val & 0x80) == 0x00) { /* len = 3 */
++ len = 3;
++ bits--;
++ getbits(ibuf, 1 , &i ,&l);
++ } else if ((val & 0xc0) == 0x80) { /* 4 <= len < 8 */
++ len = 0x04 | ((val>>4) & 0x03);
++ bits -= 4;
++ getbits(ibuf, 4 , &i ,&l);
++ } else if ((val & 0xe0) == 0xc0) { /* 8 <= len < 16 */
++ len = 0x08 | ((val>>2) & 0x07);
++ bits -= 6;
++ getbits(ibuf, 6 , &i ,&l);
++ } else if ((val & 0xf0) == 0xe0) { /* 16 <= len < 32 */
++ len = 0x10 | (val & 0x0f);
++ bits -= 8;
++ i++;
++ } else {
++ bits -= 8;
++ val = (val << 8) | getbyte(ibuf, ++i, l);
++ if ((val & 0xf800) == 0xf000) { /* 32 <= len < 64 */
++ len = 0x0020 | ((val >> 6) & 0x001f);
++ bits -= 2;
++ getbits(ibuf, 2 , &i ,&l);
++ } else if ((val & 0xfc00) == 0xf800) { /* 64 <= len < 128 */
++ len = 0x0040 | ((val >> 4) & 0x003f);
++ bits -= 4;
++ getbits(ibuf, 4 , &i ,&l);
++ } else if ((val & 0xfe00) == 0xfc00) { /* 128 <= len < 256 */
++ len = 0x0080 | ((val >> 2) & 0x007f);
++ bits -= 6;
++ getbits(ibuf, 6 , &i ,&l);
++ } else if ((val & 0xff00) == 0xfe00) { /* 256 <= len < 512 */
++ len = 0x0100 | (val & 0x00ff);
++ bits -= 8;
++ i++;
++ } else {
++ bits -= 8;
++ val = (val << 8) | getbyte(ibuf, ++i, l);
++ if ((val & 0xff8000) == 0xff0000) { /* 512 <= len < 1024 */
++ len = 0x000200 | ((val >> 6) & 0x0001ff);
++ bits -= 2;
++ getbits(ibuf, 2 , &i ,&l);
++ } else if ((val & 0xffc000) == 0xff8000) {/* 1024 <= len < 2048 */
++ len = 0x000400 | ((val >> 4) & 0x0003ff);
++ bits -= 4;
++ getbits(ibuf, 4 , &i ,&l);
++ } else if ((val & 0xffe000) == 0xffc000) {/* 2048 <= len < 4096 */
++ len = 0x000800 | ((val >> 2) & 0x0007ff);
++ bits -= 6;
++ getbits(ibuf, 6 , &i ,&l);
++ } else if ((val & 0xfff000) == 0xffe000) {/* 4096 <= len < 8192 */
++ len = 0x001000 | (val & 0x000fff);
++ bits -= 8;
++ i++;
++ } else { /* this shouldn't happen */
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: wrong length code: 0x%X\n",
++ __FUNCTION__, state->unit, val);
++ return DECOMP_ERROR;
++ }
++ }
++ }
++ s = state->hist + state->histptr;
++ state->histptr += len;
++ olen += len;
++ if (state->histptr < 2*MPPE_HIST_LEN) {
++ /* copy uncompressed bytes to the history */
++
++ /* In some cases len may be greater than off. It means that memory
++ * areas pointed by s and s-off overlap. I had used memmove() here
++ * because I thought that it acts as libc's version. Unfortunately,
++ * I was wrong. :-) I got strange errors sometimes. Wilfried suggested
++ * using of byte by byte copying here and strange errors disappeared.
++ */
++ lamecopy(s, s - off, len);
++ } else {
++ /* buffer overflow; drop packet */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: trying to write outside history "
++ "buffer\n", __FUNCTION__, state->unit);
++ return DECOMP_ERROR;
++ }
++ }
++
++ /* Do PFC decompression */
++ len = olen;
++ if ((history[0] & 0x01) != 0) {
++ obuf[0] = 0;
++ obuf++;
++ len++;
++ }
++
++ if (len <= osize) {
++ /* copy uncompressed packet to the output buffer */
++ memcpy(obuf, history, olen);
++ } else {
++ /* buffer overflow; drop packet */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: too big uncompressed packet: %d\n",
++ __FUNCTION__, state->unit, len + (PPP_HDRLEN / 2));
++ return DECOMP_ERROR;
++ }
++
++ return (int) len;
++}
++
++int
++mppe_decompress(void *arg, unsigned char *ibuf, int isize,
++ unsigned char *obuf, int osize)
++{
++ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
++ int seq, bits, uncomplen;
++
++ if (isize <= PPP_HDRLEN + MPPE_OVHD) {
++ if (state->debug) {
++ printk(KERN_DEBUG "%s%d: short packet (len=%d)\n", __FUNCTION__,
++ state->unit, isize);
++ }
++ return DECOMP_ERROR;
++ }
++
++ /* Get coherency counter and control bits from input buffer */
++ seq = MPPE_CCOUNT(ibuf);
++ bits = MPPE_BITS(ibuf);
++
++ if (state->stateless) {
++ /* RFC 3078, sec 8.1. */
++ mppe_increase_ccount(state);
++ if ((seq != state->ccount) && state->debug)
++ printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n",
++ __FUNCTION__, state->unit, seq, state->ccount);
++ while (seq != state->ccount)
++ mppe_increase_ccount(state);
++ } else {
++ /* RFC 3078, sec 8.2. */
++ if (state->flushexpected) { /* discard state */
++ if ((bits & MPPE_BIT_FLUSHED)) { /* we received expected FLUSH bit */
++ while (seq != state->ccount)
++ mppe_increase_ccount(state);
++ state->flushexpected = 0;
++ } else /* drop packet*/
++ return DECOMP_ERROR;
++ } else { /* normal state */
++ mppe_increase_ccount(state);
++ if (seq != state->ccount) {
++ /* Packet loss detected, enter the discard state. */
++ if (state->debug)
++ printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n",
++ __FUNCTION__, state->unit, seq, state->ccount);
++ state->flushexpected = 1;
++ return DECOMP_ERROR;
++ }
++ }
++ if (state->mppe && (bits & MPPE_BIT_FLUSHED)) {
++ arc4_setkey(state, state->session_key, state->keylen);
++ }
++ }
++
++ if (state->mppc && (bits & (MPPE_BIT_FLUSHED | MPPE_BIT_RESET))) {
++ state->histptr = MPPE_HIST_LEN;
++ if ((bits & MPPE_BIT_FLUSHED)) {
++ memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8));
++ } else
++ if ((bits & MPPE_BIT_RESET)) {
++ memcpy(state->hist, state->hist + MPPE_HIST_LEN, MPPE_HIST_LEN);
++ }
++ }
++
++ /* Fill in the first part of the PPP header. The protocol field
++ comes from the decompressed data. */
++ obuf[0] = PPP_ADDRESS(ibuf);
++ obuf[1] = PPP_CONTROL(ibuf);
++ obuf += PPP_HDRLEN / 2;
++
++ if (state->mppe) { /* process encrypted packet */
++ if ((bits & MPPE_BIT_ENCRYPTED)) {
++ /* OK, packet encrypted, so decrypt it */
++ if (state->mppc && (bits & MPPE_BIT_COMP)) {
++ /* Hack warning !!! RC4 implementation which we use does
++ decryption "in place" - it means that input and output
++ buffers can be *the same* memory area. Therefore we don't
++ need to use a temporary buffer. But be careful - other
++ implementations don't have to be so nice. */
++ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize -
++ PPP_HDRLEN - (MPPE_OVHD / 2), ibuf + PPP_HDRLEN +
++ (MPPE_OVHD / 2));
++ uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN +
++ (MPPE_OVHD / 2), obuf, isize -
++ PPP_HDRLEN - (MPPE_OVHD / 2),
++ osize - (PPP_HDRLEN / 2));
++ if (uncomplen == DECOMP_ERROR) {
++ state->flushexpected = 1;
++ return DECOMP_ERROR;
++ }
++ uncomplen += PPP_HDRLEN / 2;
++ (state->stats).comp_bytes += isize;
++ (state->stats).comp_packets++;
++ } else {
++ uncomplen = isize - MPPE_OVHD;
++ /* Decrypt the first byte in order to check if it is
++ compressed or uncompressed protocol field */
++ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), 1, obuf);
++ /* Do PFC decompression */
++ if ((obuf[0] & 0x01) != 0) {
++ obuf[1] = obuf[0];
++ obuf[0] = 0;
++ obuf++;
++ uncomplen++;
++ }
++ /* And finally, decrypt the rest of the frame. */
++ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2) + 1,
++ isize - PPP_HDRLEN - (MPPE_OVHD / 2) - 1, obuf + 1);
++ (state->stats).inc_bytes += isize;
++ (state->stats).inc_packets++;
++ }
++ } else { /* this shouldn't happen */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: encryption negotiated but not an "
++ "encrypted packet received\n", __FUNCTION__, state->unit);
++ mppe_change_key(state, 0);
++ state->flushexpected = 1;
++ return DECOMP_ERROR;
++ }
++ } else {
++ if (state->mppc) { /* no MPPE, only MPPC */
++ if ((bits & MPPE_BIT_COMP)) {
++ uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN +
++ (MPPE_OVHD / 2), obuf, isize -
++ PPP_HDRLEN - (MPPE_OVHD / 2),
++ osize - (PPP_HDRLEN / 2));
++ if (uncomplen == DECOMP_ERROR) {
++ state->flushexpected = 1;
++ return DECOMP_ERROR;
++ }
++ uncomplen += PPP_HDRLEN / 2;
++ (state->stats).comp_bytes += isize;
++ (state->stats).comp_packets++;
++ } else {
++ memcpy(obuf, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize -
++ PPP_HDRLEN - (MPPE_OVHD / 2));
++ uncomplen = isize - MPPE_OVHD;
++ (state->stats).inc_bytes += isize;
++ (state->stats).inc_packets++;
++ }
++ } else { /* this shouldn't happen */
++ if (state->debug)
++ printk(KERN_ERR "%s%d: error - not an MPPC or MPPE frame "
++ "received\n", __FUNCTION__, state->unit);
++ state->flushexpected = 1;
++ return DECOMP_ERROR;
++ }
++ }
++
++ (state->stats).unc_bytes += uncomplen;
++ (state->stats).unc_packets++;
++
++ return uncomplen;
++}
++
++
++/************************************************************
++ * Module interface table
++ ************************************************************/
++
++/* These are in ppp_generic.c */
++extern int ppp_register_compressor (struct compressor *cp);
++extern void ppp_unregister_compressor (struct compressor *cp);
++
++/*
++ * Functions exported to ppp_generic.c.
++ *
++ * In case of MPPC/MPPE there is no need to process incompressible data
++ * because such a data is sent in MPPC/MPPE frame. Therefore the (*incomp)
++ * callback function isn't needed.
++ */
++struct compressor ppp_mppe = {
++ .compress_proto = CI_MPPE,
++ .comp_alloc = mppe_comp_alloc,
++ .comp_free = mppe_comp_free,
++ .comp_init = mppe_comp_init,
++ .comp_reset = mppe_comp_reset,
++ .compress = mppe_compress,
++ .comp_stat = mppe_stats,
++ .decomp_alloc = mppe_decomp_alloc,
++ .decomp_free = mppe_comp_free,
++ .decomp_init = mppe_decomp_init,
++ .decomp_reset = mppe_decomp_reset,
++ .decompress = mppe_decompress,
++ .incomp = NULL,
++ .decomp_stat = mppe_stats,
++ .owner = THIS_MODULE
++};
++
++/************************************************************
++ * Module support routines
++ ************************************************************/
++
++int __init mppe_module_init(void)
++{
++ int answer;
++
++ if (!(crypto_alg_available("arc4", 0) && crypto_alg_available("sha1", 0))) {
++ printk(KERN_ERR "Kernel doesn't provide ARC4 and/or SHA1 algorithms "
++ "required by MPPE/MPPC. Check CryptoAPI configuration.\n");
++ return -ENODEV;
++ }
++
++ /* Allocate space for SHAPad1, SHAPad2 and ... */
++ sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL);
++ if (sha_pad == NULL)
++ return -ENOMEM;
++ /* ... initialize them */
++ memset(sha_pad->sha_pad1, 0x00, sizeof(sha_pad->sha_pad1));
++ memset(sha_pad->sha_pad2, 0xf2, sizeof(sha_pad->sha_pad2));
++
++ answer = ppp_register_compressor(&ppp_mppe);
++ if (answer == 0) {
++ printk(KERN_INFO "MPPE/MPPC encryption/compression module registered\n");
++ }
++ return answer;
++}
++
++void __exit mppe_module_cleanup(void)
++{
++ kfree(sha_pad);
++ ppp_unregister_compressor(&ppp_mppe);
++ printk(KERN_INFO "MPPE/MPPC encryption/compression module unregistered\n");
++}
++
++module_init(mppe_module_init);
++module_exit(mppe_module_cleanup);
++
++MODULE_AUTHOR("Jan Dubiec <jdx@slackware.pl>");
++MODULE_DESCRIPTION("MPPE/MPPC encryption/compression module for Linux");
++MODULE_VERSION("1.3");
++MODULE_LICENSE("Dual BSD/GPL");
++MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE));
+--- a/include/linux/crypto.h
++++ b/include/linux/crypto.h
+@@ -309,7 +309,18 @@ int crypto_unregister_alg(struct crypto_
+ /*
+ * Algorithm query interface.
+ */
++#ifdef CONFIG_CRYPTO
++int crypto_alg_available(const char *name, u32 flags)
++ __deprecated_for_modules;
+ int crypto_has_alg(const char *name, u32 type, u32 mask);
++#else
++static int crypto_alg_available(const char *name, u32 flags)
++ __deprecated_for_modules;
++static inline int crypto_has_alg(const char *name, u32 type, u32 mask)
++{
++ return 0;
++}
++#endif
+
+ /*
+ * Transforms: user-instantiated objects which encapsulate algorithms
+@@ -1101,6 +1112,16 @@ static inline void crypto_cipher_decrypt
+ dst, src);
+ }
+
++void crypto_digest_init(struct crypto_tfm *tfm) __deprecated_for_modules;
++void crypto_digest_update(struct crypto_tfm *tfm,
++ struct scatterlist *sg, unsigned int nsg)
++ __deprecated_for_modules;
++void crypto_digest_final(struct crypto_tfm *tfm, u8 *out)
++ __deprecated_for_modules;
++void crypto_digest_digest(struct crypto_tfm *tfm,
++ struct scatterlist *sg, unsigned int nsg, u8 *out)
++ __deprecated_for_modules;
++
+ static inline struct crypto_hash *__crypto_hash_cast(struct crypto_tfm *tfm)
+ {
+ return (struct crypto_hash *)tfm;
+@@ -1113,6 +1134,14 @@ static inline struct crypto_hash *crypto
+ return __crypto_hash_cast(tfm);
+ }
+
++static int crypto_digest_setkey(struct crypto_tfm *tfm, const u8 *key,
++ unsigned int keylen) __deprecated;
++static inline int crypto_digest_setkey(struct crypto_tfm *tfm,
++ const u8 *key, unsigned int keylen)
++{
++ return tfm->crt_hash.setkey(crypto_hash_cast(tfm), key, keylen);
++}
++
+ static inline struct crypto_hash *crypto_alloc_hash(const char *alg_name,
+ u32 type, u32 mask)
+ {
+--- a/include/linux/ppp-comp.h
++++ b/include/linux/ppp-comp.h
+@@ -26,7 +26,7 @@
+ */
+
+ /*
+- * ==FILEVERSION 980319==
++ * ==FILEVERSION 20040509==
+ *
+ * NOTE TO MAINTAINERS:
+ * If you modify this file at all, please set the above date.
+@@ -78,7 +78,7 @@ struct compressor {
+
+ /* Compress a packet */
+ int (*compress) (void *state, unsigned char *rptr,
+- unsigned char *obuf, int isize, int osize);
++ unsigned char *obuf, int isize, int osize);
+
+ /* Return compression statistics */
+ void (*comp_stat) (void *state, struct compstat *stats);
+@@ -99,7 +99,7 @@ struct compressor {
+
+ /* Decompress a packet. */
+ int (*decompress) (void *state, unsigned char *ibuf, int isize,
+- unsigned char *obuf, int osize);
++ unsigned char *obuf, int osize);
+
+ /* Update state for an incompressible packet received */
+ void (*incomp) (void *state, unsigned char *ibuf, int icnt);
+@@ -109,8 +109,6 @@ struct compressor {
+
+ /* Used in locking compressor modules */
+ struct module *owner;
+- /* Extra skb space needed by the compressor algorithm */
+- unsigned int comp_extra;
+ };
+
+ /*
+@@ -191,11 +189,40 @@ struct compressor {
+ #define DEFLATE_CHK_SEQUENCE 0
+
+ /*
+- * Definitions for MPPE.
++ * Definitions for MPPE/MPPC.
+ */
+
+-#define CI_MPPE 18 /* config option for MPPE */
+-#define CILEN_MPPE 6 /* length of config option */
++#define CI_MPPE 18 /* config option for MPPE */
++#define CILEN_MPPE 6 /* length of config option */
++
++#define MPPE_OVHD 4 /* MPPE overhead */
++#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
++
++#define MPPE_STATELESS 0x01 /* configuration bit H */
++#define MPPE_40BIT 0x20 /* configuration bit L */
++#define MPPE_56BIT 0x80 /* configuration bit M */
++#define MPPE_128BIT 0x40 /* configuration bit S */
++#define MPPE_MPPC 0x01 /* configuration bit C */
++
++/*
++ * Definitions for Stac LZS.
++ */
++
++#define CI_LZS 17 /* config option for Stac LZS */
++#define CILEN_LZS 5 /* length of config option */
++
++#define LZS_OVHD 4 /* max. LZS overhead */
++#define LZS_HIST_LEN 2048 /* LZS history size */
++#define LZS_MAX_CCOUNT 0x0FFF /* max. coherency counter value */
++
++#define LZS_MODE_NONE 0
++#define LZS_MODE_LCB 1
++#define LZS_MODE_CRC 2
++#define LZS_MODE_SEQ 3
++#define LZS_MODE_EXT 4
++
++#define LZS_EXT_BIT_FLUSHED 0x80 /* bit A */
++#define LZS_EXT_BIT_COMP 0x20 /* bit C */
+
+ /*
+ * Definitions for other, as yet unsupported, compression methods.
--
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