pppd: add support for MPPE and MPPC encryption and compression protocols

This is a forward ported version of ppp-2.4.3-mppe-mppc-1.1.patch.gz found on
http://mppe-mppc.alphacron.de/ .

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

--- a/include/linux/ppp-comp.h
+++ b/include/linux/ppp-comp.h
@@ -36,7 +36,7 @@
  */
 
 /*
- *  ==FILEVERSION 20020319==
+ *  ==FILEVERSION 20020715==
  *
  *  NOTE TO MAINTAINERS:
  *     If you modify this file at all, please set the above date.
@@ -201,6 +201,33 @@ struct compressor {
 #define CI_MPPE			18	/* config option for MPPE */
 #define CILEN_MPPE		6	/* length of config option */
 
+/* MPPE/MPPC definitions by J.D.*/
+#define MPPE_STATELESS          MPPE_H_BIT	/* configuration bit H */
+#define MPPE_40BIT              MPPE_L_BIT	/* configuration bit L */
+#define MPPE_56BIT              MPPE_M_BIT	/* configuration bit M */
+#define MPPE_128BIT             MPPE_S_BIT	/* configuration bit S */
+#define MPPE_MPPC               MPPE_C_BIT	/* 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.
  */
--- a/include/net/ppp-comp.h
+++ b/include/net/ppp-comp.h
@@ -168,6 +168,33 @@ struct compressor {
 #define CI_MPPE			18	/* config option for MPPE */
 #define CILEN_MPPE		6	/* length of config option */
 
+/* MPPE/MPPC definitions by J.D.*/
+#define MPPE_STATELESS          MPPE_H_BIT	/* configuration bit H */
+#define MPPE_40BIT              MPPE_L_BIT	/* configuration bit L */
+#define MPPE_56BIT              MPPE_M_BIT	/* configuration bit M */
+#define MPPE_128BIT             MPPE_S_BIT	/* configuration bit S */
+#define MPPE_MPPC               MPPE_C_BIT	/* 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.
  */
--- a/pppd/ccp.c
+++ b/pppd/ccp.c
@@ -62,12 +62,10 @@ static int setdeflate __P((char **));
 static char bsd_value[8];
 static char deflate_value[8];
 
-/*
- * Option variables.
- */
 #ifdef MPPE
-bool refuse_mppe_stateful = 1;		/* Allow stateful mode? */
-#endif
+static int setmppe(char **);
+static int setnomppe(void);
+#endif /* MPPE */
 
 static option_t ccp_option_list[] = {
     { "noccp", o_bool, &ccp_protent.enabled_flag,
@@ -108,54 +106,36 @@ static option_t ccp_option_list[] = {
       "don't allow Predictor-1", OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLR,
       &ccp_allowoptions[0].predictor_1 },
 
+    { "lzs", o_bool, &ccp_wantoptions[0].lzs,
+      "request Stac LZS", 1, &ccp_allowoptions[0].lzs, OPT_PRIO },
+    { "+lzs", o_bool, &ccp_wantoptions[0].lzs,
+      "request Stac LZS", 1, &ccp_allowoptions[0].lzs, OPT_ALIAS | OPT_PRIO },
+    { "nolzs", o_bool, &ccp_wantoptions[0].lzs,
+      "don't allow Stac LZS", OPT_PRIOSUB | OPT_A2CLR,
+      &ccp_allowoptions[0].lzs },
+    { "-lzs", o_bool, &ccp_wantoptions[0].lzs,
+      "don't allow Stac LZS", OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLR,
+      &ccp_allowoptions[0].lzs },
+
 #ifdef MPPE
-    /* MPPE options are symmetrical ... we only set wantoptions here */
-    { "require-mppe", o_bool, &ccp_wantoptions[0].mppe,
-      "require MPPE encryption",
-      OPT_PRIO | MPPE_OPT_40 | MPPE_OPT_128 },
-    { "+mppe", o_bool, &ccp_wantoptions[0].mppe,
-      "require MPPE encryption",
-      OPT_ALIAS | OPT_PRIO | MPPE_OPT_40 | MPPE_OPT_128 },
-    { "nomppe", o_bool, &ccp_wantoptions[0].mppe,
-      "don't allow MPPE encryption", OPT_PRIO },
-    { "-mppe", o_bool, &ccp_wantoptions[0].mppe,
-      "don't allow MPPE encryption", OPT_ALIAS | OPT_PRIO },
-
-    /* We use ccp_allowoptions[0].mppe as a junk var ... it is reset later */
-    { "require-mppe-40", o_bool, &ccp_allowoptions[0].mppe,
-      "require MPPE 40-bit encryption", OPT_PRIO | OPT_A2OR | MPPE_OPT_40,
-      &ccp_wantoptions[0].mppe },
-    { "+mppe-40", o_bool, &ccp_allowoptions[0].mppe,
-      "require MPPE 40-bit encryption", OPT_PRIO | OPT_A2OR | MPPE_OPT_40,
-      &ccp_wantoptions[0].mppe },
-    { "nomppe-40", o_bool, &ccp_allowoptions[0].mppe,
-      "don't allow MPPE 40-bit encryption",
-      OPT_PRIOSUB | OPT_A2CLRB | MPPE_OPT_40, &ccp_wantoptions[0].mppe },
-    { "-mppe-40", o_bool, &ccp_allowoptions[0].mppe,
-      "don't allow MPPE 40-bit encryption",
-      OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLRB | MPPE_OPT_40,
-      &ccp_wantoptions[0].mppe },
-
-    { "require-mppe-128", o_bool, &ccp_allowoptions[0].mppe,
-      "require MPPE 128-bit encryption", OPT_PRIO | OPT_A2OR | MPPE_OPT_128,
-      &ccp_wantoptions[0].mppe },
-    { "+mppe-128", o_bool, &ccp_allowoptions[0].mppe,
-      "require MPPE 128-bit encryption",
-      OPT_ALIAS | OPT_PRIO | OPT_A2OR | MPPE_OPT_128,
-      &ccp_wantoptions[0].mppe },
-    { "nomppe-128", o_bool, &ccp_allowoptions[0].mppe,
-      "don't allow MPPE 128-bit encryption",
-      OPT_PRIOSUB | OPT_A2CLRB | MPPE_OPT_128, &ccp_wantoptions[0].mppe },
-    { "-mppe-128", o_bool, &ccp_allowoptions[0].mppe,
-      "don't allow MPPE 128-bit encryption",
-      OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLRB | MPPE_OPT_128,
-      &ccp_wantoptions[0].mppe },
-
-    /* strange one; we always request stateless, but will we allow stateful? */
-    { "mppe-stateful", o_bool, &refuse_mppe_stateful,
-      "allow MPPE stateful mode", OPT_PRIO },
-    { "nomppe-stateful", o_bool, &refuse_mppe_stateful,
-      "disallow MPPE stateful mode", OPT_PRIO | 1 },
+    { "mppc", o_bool, &ccp_wantoptions[0].mppc,
+      "request MPPC compression", 1, &ccp_allowoptions[0].mppc },
+    { "+mppc", o_bool, &ccp_wantoptions[0].mppc,
+      "request MPPC compression", 1, &ccp_allowoptions[0].mppc, OPT_ALIAS },
+    { "nomppc", o_bool, &ccp_wantoptions[0].mppc,
+      "don't allow MPPC compression", OPT_PRIOSUB | OPT_A2CLR,
+      &ccp_allowoptions[0].mppc },
+    { "-mppc", o_bool, &ccp_wantoptions[0].mppc,
+      "don't allow MPPC compression", OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLR,
+      &ccp_allowoptions[0].mppc },
+    { "mppe", o_special, (void *)setmppe,
+      "request MPPE encryption" },
+    { "+mppe", o_special, (void *)setmppe,
+      "request MPPE encryption" },
+    { "nomppe", o_special_noarg, (void *)setnomppe,
+      "don't allow MPPE encryption" },
+    { "-mppe", o_special_noarg, (void *)setnomppe,
+      "don't allow MPPE encryption" },
 #endif /* MPPE */
 
     { NULL }
@@ -241,7 +221,7 @@ static fsm_callbacks ccp_callbacks = {
  */
 #define ANY_COMPRESS(opt)	((opt).deflate || (opt).bsd_compress \
 				 || (opt).predictor_1 || (opt).predictor_2 \
-				 || (opt).mppe)
+				 || (opt).lzs || (opt).mppc || (opt).mppe)
 
 /*
  * Local state (mainly for handling reset-reqs and reset-acks).
@@ -344,6 +324,100 @@ setdeflate(argv)
     return 1;
 }
 
+#ifdef MPPE
+/*
+ * Functions called from config options
+ */
+/* 
+   MPPE suboptions:
+	required - require MPPE; disconnect if peer doesn't support it
+	stateless - use stateless mode
+	no40 - disable 40 bit keys
+	no56 - disable 56 bit keys
+	no128 - disable 128 bit keys
+*/
+int setmppe(char **argv)
+{
+    int i;
+    char *str, cmdbuf[16];
+
+    ccp_allowoptions[0].mppe = 1;
+    ccp_allowoptions[0].mppe_40 = 1;
+    ccp_allowoptions[0].mppe_56 = 1;
+    ccp_allowoptions[0].mppe_128 = 1;
+    ccp_allowoptions[0].mppe_stateless = 0;
+    ccp_wantoptions[0].mppe = 0;
+
+    str = *argv;
+
+    while (1) {
+	i = 0;
+	memset(cmdbuf, '\0', 16);
+	while ((i < 16) && (*str != ',') && (*str != '\0'))
+	    cmdbuf[i++] = *str++;
+	cmdbuf[i] = '\0';
+	if (!strncasecmp(cmdbuf, "no40", strlen("no40"))) {
+	    ccp_allowoptions[0].mppe_40 = 0;
+	    goto next_param;
+	} else if (!strncasecmp(cmdbuf, "no56", strlen("no56"))) {
+	    ccp_allowoptions[0].mppe_56 = 0;
+	    goto next_param;
+	} else if (!strncasecmp(cmdbuf, "no128", strlen("no128"))) {
+	    ccp_allowoptions[0].mppe_128 = 0;
+	    goto next_param;
+	} else if (!strncasecmp(cmdbuf, "stateless", strlen("stateless"))) {
+	    ccp_allowoptions[0].mppe_stateless = 1;
+	    goto next_param;
+	} else if (!strncasecmp(cmdbuf, "required", strlen("required"))) {
+	    ccp_wantoptions[0].mppe = 1;
+	    goto next_param;
+	} else {
+	    option_error("invalid parameter '%s' for mppe option", cmdbuf);
+	    return 0;
+	}
+
+    next_param:
+	if (*str == ',') {
+	    str++;
+	    continue;
+	}
+	if (*str == '\0') {
+	    if (!(ccp_allowoptions[0].mppe_40 || ccp_allowoptions[0].mppe_56 ||
+		  ccp_allowoptions[0].mppe_128)) {
+		if (ccp_wantoptions[0].mppe == 1) {
+		    option_error("You require MPPE but you have switched off "
+				 "all encryption key lengths.");
+		    return 0;
+		}
+		ccp_wantoptions[0].mppe = ccp_allowoptions[0].mppe = 0;
+		ccp_wantoptions[0].mppe_stateless =
+		    ccp_allowoptions[0].mppe_stateless = 0;
+	    } else {
+		ccp_allowoptions[0].mppe = 1;
+		ccp_wantoptions[0].mppe_stateless =
+		    ccp_allowoptions[0].mppe_stateless;
+		if (ccp_wantoptions[0].mppe == 1) {
+		    ccp_wantoptions[0].mppe_40 = ccp_allowoptions[0].mppe_40;
+		    ccp_wantoptions[0].mppe_56 = ccp_allowoptions[0].mppe_56;
+		    ccp_wantoptions[0].mppe_128 = ccp_allowoptions[0].mppe_128;
+		}
+	    }
+	    return 1;
+	}
+    }
+}
+
+int setnomppe(void)
+{
+    ccp_wantoptions[0].mppe = ccp_allowoptions[0].mppe = 0;
+    ccp_wantoptions[0].mppe_40 = ccp_allowoptions[0].mppe_40 = 0;
+    ccp_wantoptions[0].mppe_56 = ccp_allowoptions[0].mppe_56 = 0;
+    ccp_wantoptions[0].mppe_128 = ccp_allowoptions[0].mppe_128 = 0;
+    ccp_wantoptions[0].mppe_stateless = ccp_allowoptions[0].mppe_stateless = 0;
+    return 1;
+}
+#endif /* MPPE */
+
 /*
  * ccp_init - initialize CCP.
  */
@@ -378,6 +452,30 @@ ccp_init(unit)
     ccp_allowoptions[0].bsd_bits = BSD_MAX_BITS;
 
     ccp_allowoptions[0].predictor_1 = 1;
+
+    ccp_wantoptions[0].lzs = 0; /* Stac LZS  - will be enabled in the future */
+    ccp_wantoptions[0].lzs_mode = LZS_MODE_SEQ;
+    ccp_wantoptions[0].lzs_hists = 1;
+    ccp_allowoptions[0].lzs = 0; /* Stac LZS  - will be enabled in the future */
+    ccp_allowoptions[0].lzs_mode = LZS_MODE_SEQ;
+    ccp_allowoptions[0].lzs_hists = 1;
+
+#ifdef MPPE
+    /* by default allow and request MPPC... */
+    ccp_wantoptions[0].mppc = ccp_allowoptions[0].mppc = 1;
+
+    /* ... and allow but don't request MPPE */
+    ccp_allowoptions[0].mppe = 1;
+    ccp_allowoptions[0].mppe_40 = 1;
+    ccp_allowoptions[0].mppe_56 = 1;
+    ccp_allowoptions[0].mppe_128 = 1;
+    ccp_allowoptions[0].mppe_stateless = 1;
+    ccp_wantoptions[0].mppe = 0;
+    ccp_wantoptions[0].mppe_40 = 0;
+    ccp_wantoptions[0].mppe_56 = 0;
+    ccp_wantoptions[0].mppe_128 = 0;
+    ccp_wantoptions[0].mppe_stateless = 0;
+#endif /* MPPE */
 }
 
 /*
@@ -455,11 +553,11 @@ ccp_input(unit, p, len)
     if (oldstate == OPENED && p[0] == TERMREQ && f->state != OPENED) {
 	notice("Compression disabled by peer.");
 #ifdef MPPE
-	if (ccp_gotoptions[unit].mppe) {
+	if (ccp_wantoptions[unit].mppe) {
 	    error("MPPE disabled, closing LCP");
 	    lcp_close(unit, "MPPE disabled by peer");
 	}
-#endif
+#endif /* MPPE */
     }
 
     /*
@@ -487,6 +585,15 @@ ccp_extcode(f, code, id, p, len)
 	    break;
 	/* send a reset-ack, which the transmitter will see and
 	   reset its compression state. */
+
+	/* In case of MPPE/MPPC or LZS we shouldn't send CCP_RESETACK,
+	   but we do it in order to reset compressor; CCP_RESETACK is
+	   then silently discarded. See functions ppp_send_frame and
+	   ppp_ccp_peek in ppp_generic.c (Linux only !!!). All the
+	   confusion is caused by the fact that CCP code is splited
+	   into two parts - one part is handled by pppd, the other one
+	   is handled by kernel. */
+
 	fsm_sdata(f, CCP_RESETACK, id, NULL, 0);
 	break;
 
@@ -515,12 +622,11 @@ ccp_protrej(unit)
     fsm_lowerdown(&ccp_fsm[unit]);
 
 #ifdef MPPE
-    if (ccp_gotoptions[unit].mppe) {
+    if (ccp_wantoptions[unit].mppe) {
 	error("MPPE required but peer negotiation failed");
 	lcp_close(unit, "MPPE required but peer negotiation failed");
     }
-#endif
-
+#endif /* MPPE */
 }
 
 /*
@@ -537,7 +643,7 @@ ccp_resetci(f)
     all_rejected[f->unit] = 0;
 
 #ifdef MPPE
-    if (go->mppe) {
+    if (go->mppe || go->mppc) {
 	ccp_options *ao = &ccp_allowoptions[f->unit];
 	int auth_mschap_bits = auth_done[f->unit];
 	int numbits;
@@ -551,80 +657,109 @@ ccp_resetci(f)
 	 * NB: If MPPE is required, all other compression opts are invalid.
 	 *     So, we return right away if we can't do it.
 	 */
+	if (ccp_wantoptions[f->unit].mppe) {
+	    /* Leave only the mschap auth bits set */
+	    auth_mschap_bits &= (CHAP_MS_WITHPEER  | CHAP_MS_PEER |
+				 CHAP_MS2_WITHPEER | CHAP_MS2_PEER);
+	    /* Count the mschap auths */
+	    auth_mschap_bits >>= CHAP_MS_SHIFT;
+	    numbits = 0;
+	    do {
+		numbits += auth_mschap_bits & 1;
+		auth_mschap_bits >>= 1;
+	    } while (auth_mschap_bits);
+	    if (numbits > 1) {
+		error("MPPE required, but auth done in both directions.");
+		lcp_close(f->unit, "MPPE required but not available");
+		return;
+	    }
+	    if (!numbits) {
+		error("MPPE required, but MS-CHAP[v2] auth not performed.");
+		lcp_close(f->unit, "MPPE required but not available");
+		return;
+	    }
 
-	/* Leave only the mschap auth bits set */
-	auth_mschap_bits &= (CHAP_MS_WITHPEER  | CHAP_MS_PEER |
-			     CHAP_MS2_WITHPEER | CHAP_MS2_PEER);
-	/* Count the mschap auths */
-	auth_mschap_bits >>= CHAP_MS_SHIFT;
-	numbits = 0;
-	do {
-	    numbits += auth_mschap_bits & 1;
-	    auth_mschap_bits >>= 1;
-	} while (auth_mschap_bits);
-	if (numbits > 1) {
-	    error("MPPE required, but auth done in both directions.");
-	    lcp_close(f->unit, "MPPE required but not available");
-	    return;
-	}
-	if (!numbits) {
-	    error("MPPE required, but MS-CHAP[v2] auth not performed.");
-	    lcp_close(f->unit, "MPPE required but not available");
-	    return;
-	}
-
-	/* A plugin (eg radius) may not have obtained key material. */
-	if (!mppe_keys_set) {
-	    error("MPPE required, but keys are not available.  "
-		  "Possible plugin problem?");
-	    lcp_close(f->unit, "MPPE required but not available");
-	    return;
-	}
-
-	/* LM auth not supported for MPPE */
-	if (auth_done[f->unit] & (CHAP_MS_WITHPEER | CHAP_MS_PEER)) {
-	    /* This might be noise */
-	    if (go->mppe & MPPE_OPT_40) {
-		notice("Disabling 40-bit MPPE; MS-CHAP LM not supported");
-		go->mppe &= ~MPPE_OPT_40;
-		ccp_wantoptions[f->unit].mppe &= ~MPPE_OPT_40;
+	    /* A plugin (eg radius) may not have obtained key material. */
+	    if (!mppe_keys_set) {
+		error("MPPE required, but keys are not available.  "
+		      "Possible plugin problem?");
+		lcp_close(f->unit, "MPPE required but not available");
+		return;
 	    }
 	}
 
-	/* Last check: can we actually negotiate something? */
-	if (!(go->mppe & (MPPE_OPT_40 | MPPE_OPT_128))) {
-	    /* Could be misconfig, could be 40-bit disabled above. */
-	    error("MPPE required, but both 40-bit and 128-bit disabled.");
-	    lcp_close(f->unit, "MPPE required but not available");
-	    return;
+	/*
+	 * Check whether the kernel knows about the various
+	 * compression methods we might request. Key material
+	 * unimportant here.
+	 */
+	if (go->mppc) {
+	    opt_buf[0] = CI_MPPE;
+	    opt_buf[1] = CILEN_MPPE;
+	    opt_buf[2] = 0;
+	    opt_buf[3] = 0;
+	    opt_buf[4] = 0;
+	    opt_buf[5] = MPPE_MPPC;
+	    if (ccp_test(f->unit, opt_buf, CILEN_MPPE, 0) <= 0)
+		go->mppc = 0;
+	}
+	if (go->mppe_40) {
+	    opt_buf[0] = CI_MPPE;
+	    opt_buf[1] = CILEN_MPPE;
+	    opt_buf[2] = MPPE_STATELESS;
+	    opt_buf[3] = 0;
+	    opt_buf[4] = 0;
+	    opt_buf[5] = MPPE_40BIT;
+	    if (ccp_test(f->unit, opt_buf, CILEN_MPPE + MPPE_MAX_KEY_LEN, 0) <= 0)
+		go->mppe_40 = 0;
+	}
+	if (go->mppe_56) {
+	    opt_buf[0] = CI_MPPE;
+	    opt_buf[1] = CILEN_MPPE;
+	    opt_buf[2] = MPPE_STATELESS;
+	    opt_buf[3] = 0;
+	    opt_buf[4] = 0;
+	    opt_buf[5] = MPPE_56BIT;
+	    if (ccp_test(f->unit, opt_buf, CILEN_MPPE + MPPE_MAX_KEY_LEN, 0) <= 0)
+		go->mppe_56 = 0;
+	}
+	if (go->mppe_128) {
+	    opt_buf[0] = CI_MPPE;
+	    opt_buf[1] = CILEN_MPPE;
+	    opt_buf[2] = MPPE_STATELESS;
+	    opt_buf[3] = 0;
+	    opt_buf[4] = 0;
+	    opt_buf[5] = MPPE_128BIT;
+	    if (ccp_test(f->unit, opt_buf, CILEN_MPPE + MPPE_MAX_KEY_LEN, 0) <= 0)
+		go->mppe_128 = 0;
+	}
+	if (!go->mppe_40 && !go->mppe_56 && !go->mppe_128) {
+	    if (ccp_wantoptions[f->unit].mppe) {
+		error("MPPE required, but kernel has no support.");
+		lcp_close(f->unit, "MPPE required but not available");
+	    }
+	    go->mppe = go->mppe_stateless = 0;
+	} else {
+	    /* MPPE is not compatible with other compression types */
+	    if (ccp_wantoptions[f->unit].mppe) {
+		ao->bsd_compress = go->bsd_compress = 0;
+		ao->predictor_1  = go->predictor_1  = 0;
+		ao->predictor_2  = go->predictor_2  = 0;
+		ao->deflate	 = go->deflate	    = 0;
+		ao->lzs		 = go->lzs	    = 0;
+	    }
 	}
-
-	/* sync options */
-	ao->mppe = go->mppe;
-	/* MPPE is not compatible with other compression types */
-	ao->bsd_compress = go->bsd_compress = 0;
-	ao->predictor_1  = go->predictor_1  = 0;
-	ao->predictor_2  = go->predictor_2  = 0;
-	ao->deflate      = go->deflate      = 0;
     }
 #endif /* MPPE */
-
-    /*
-     * Check whether the kernel knows about the various
-     * compression methods we might request.
-     */
-#ifdef MPPE
-    if (go->mppe) {
-	opt_buf[0] = CI_MPPE;
-	opt_buf[1] = CILEN_MPPE;
-	MPPE_OPTS_TO_CI(go->mppe, &opt_buf[2]);
-	/* Key material unimportant here. */
-	if (ccp_test(f->unit, opt_buf, CILEN_MPPE + MPPE_MAX_KEY_LEN, 0) <= 0) {
-	    error("MPPE required, but kernel has no support.");
-	    lcp_close(f->unit, "MPPE required but not available");
-	}
+    if (go->lzs) {
+	opt_buf[0] = CI_LZS;
+	opt_buf[1] = CILEN_LZS;
+	opt_buf[2] = go->lzs_hists >> 8;
+	opt_buf[3] = go->lzs_hists & 0xff;
+	opt_buf[4] = LZS_MODE_SEQ;
+	if (ccp_test(f->unit, opt_buf, CILEN_LZS, 0) <= 0)
+	    go->lzs = 0;
     }
-#endif
     if (go->bsd_compress) {
 	opt_buf[0] = CI_BSD_COMPRESS;
 	opt_buf[1] = CILEN_BSD_COMPRESS;
@@ -679,7 +814,8 @@ ccp_cilen(f)
 	+ (go->deflate? CILEN_DEFLATE: 0)
 	+ (go->predictor_1? CILEN_PREDICTOR_1: 0)
 	+ (go->predictor_2? CILEN_PREDICTOR_2: 0)
-	+ (go->mppe? CILEN_MPPE: 0);
+	+ (go->lzs? CILEN_LZS: 0)
+	+ ((go->mppe || go->mppc)? CILEN_MPPE: 0);
 }
 
 /*
@@ -693,6 +829,8 @@ ccp_addci(f, p, lenp)
 {
     int res;
     ccp_options *go = &ccp_gotoptions[f->unit];
+    ccp_options *ao = &ccp_allowoptions[f->unit];
+    ccp_options *wo = &ccp_wantoptions[f->unit];
     u_char *p0 = p;
 
     /*
@@ -701,22 +839,43 @@ ccp_addci(f, p, lenp)
      * in case it gets Acked.
      */
 #ifdef MPPE
-    if (go->mppe) {
+    if (go->mppe || go->mppc || (!wo->mppe && ao->mppe)) {
 	u_char opt_buf[CILEN_MPPE + MPPE_MAX_KEY_LEN];
 
-	p[0] = opt_buf[0] = CI_MPPE;
-	p[1] = opt_buf[1] = CILEN_MPPE;
-	MPPE_OPTS_TO_CI(go->mppe, &p[2]);
-	MPPE_OPTS_TO_CI(go->mppe, &opt_buf[2]);
+	p[0] = CI_MPPE;
+	p[1] = CILEN_MPPE;
+	p[2] = (go->mppe_stateless ? MPPE_STATELESS : 0);
+	p[3] = 0;
+	p[4] = 0;
+	p[5] = (go->mppe_40 ? MPPE_40BIT : 0) | (go->mppe_56 ? MPPE_56BIT : 0) |
+	    (go->mppe_128 ? MPPE_128BIT : 0) | (go->mppc ? MPPE_MPPC : 0);
+
+	BCOPY(p, opt_buf, CILEN_MPPE);
 	BCOPY(mppe_recv_key, &opt_buf[CILEN_MPPE], MPPE_MAX_KEY_LEN);
 	res = ccp_test(f->unit, opt_buf, CILEN_MPPE + MPPE_MAX_KEY_LEN, 0);
-	if (res > 0)
+	if (res > 0) {
 	    p += CILEN_MPPE;
-	else
+	} else {
 	    /* This shouldn't happen, we've already tested it! */
-	    lcp_close(f->unit, "MPPE required but not available in kernel");
+	    go->mppe = go->mppe_40 = go->mppe_56 = go->mppe_128 =
+		go->mppe_stateless = go->mppc = 0;
+	    if (ccp_wantoptions[f->unit].mppe)
+		lcp_close(f->unit, "MPPE required but not available in kernel");
+	}
+    }
+#endif /* MPPE */
+    if (go->lzs) {
+	p[0] = CI_LZS;
+	p[1] = CILEN_LZS;
+	p[2] = go->lzs_hists >> 8;
+	p[3] = go->lzs_hists & 0xff;
+	p[4] = LZS_MODE_SEQ;
+	res = ccp_test(f->unit, p, CILEN_LZS, 0);
+	if (res > 0) {
+	    p += CILEN_LZS;
+	} else
+	    go->lzs = 0;
     }
-#endif
     if (go->deflate) {
 	p[0] = go->deflate_correct? CI_DEFLATE: CI_DEFLATE_DRAFT;
 	p[1] = CILEN_DEFLATE;
@@ -802,7 +961,7 @@ ccp_addci(f, p, lenp)
 
 /*
  * ccp_ackci - process a received configure-ack, and return
- * 1 iff the packet was OK.
+ * 1 if the packet was OK.
  */
 static int
 ccp_ackci(f, p, len)
@@ -811,24 +970,44 @@ ccp_ackci(f, p, len)
     int len;
 {
     ccp_options *go = &ccp_gotoptions[f->unit];
+    ccp_options *ao = &ccp_allowoptions[f->unit];
+    ccp_options *wo = &ccp_wantoptions[f->unit];
     u_char *p0 = p;
 
 #ifdef MPPE
-    if (go->mppe) {
-	u_char opt_buf[CILEN_MPPE];
-
-	opt_buf[0] = CI_MPPE;
-	opt_buf[1] = CILEN_MPPE;
-	MPPE_OPTS_TO_CI(go->mppe, &opt_buf[2]);
-	if (len < CILEN_MPPE || memcmp(opt_buf, p, CILEN_MPPE))
+    if (go->mppe || go->mppc || (!wo->mppe && ao->mppe)) {
+	if (len < CILEN_MPPE
+	    || p[1] != CILEN_MPPE || p[0] != CI_MPPE
+	    || p[2] != (go->mppe_stateless ? MPPE_STATELESS : 0)
+	    || p[3] != 0
+	    || p[4] != 0
+	    || (p[5] != ((go->mppe_40 ? MPPE_40BIT : 0) |
+			 (go->mppc ? MPPE_MPPC : 0))
+		&& p[5] != ((go->mppe_56 ? MPPE_56BIT : 0) |
+			    (go->mppc ? MPPE_MPPC : 0))
+		&& p[5] != ((go->mppe_128 ? MPPE_128BIT : 0) |
+			    (go->mppc ? MPPE_MPPC : 0))))
 	    return 0;
+	if (go->mppe_40 || go->mppe_56 || go->mppe_128)
+	    go->mppe = 1;
 	p += CILEN_MPPE;
 	len -= CILEN_MPPE;
+	/* Cope with first/fast ack */
+	if (p == p0 && len == 0)
+	    return 1;
+    }
+#endif /* MPPE */
+    if (go->lzs) {
+	if (len < CILEN_LZS || p[0] != CI_LZS || p[1] != CILEN_LZS
+	    || p[2] != go->lzs_hists>>8 || p[3] != (go->lzs_hists&0xff)
+	    || p[4] != LZS_MODE_SEQ)
+	    return 0;
+	p += CILEN_LZS;
+	len -= CILEN_LZS;
 	/* XXX Cope with first/fast ack */
-	if (len == 0)
+	if (p == p0 && len == 0)
 	    return 1;
     }
-#endif
     if (go->deflate) {
 	if (len < CILEN_DEFLATE
 	    || p[0] != (go->deflate_correct? CI_DEFLATE: CI_DEFLATE_DRAFT)
@@ -901,6 +1080,8 @@ ccp_nakci(f, p, len, treat_as_reject)
     int treat_as_reject;
 {
     ccp_options *go = &ccp_gotoptions[f->unit];
+    ccp_options *ao = &ccp_allowoptions[f->unit];
+    ccp_options *wo = &ccp_wantoptions[f->unit];
     ccp_options no;		/* options we've seen already */
     ccp_options try;		/* options to ask for next time */
 
@@ -908,28 +1089,100 @@ ccp_nakci(f, p, len, treat_as_reject)
     try = *go;
 
 #ifdef MPPE
-    if (go->mppe && len >= CILEN_MPPE
-	&& p[0] == CI_MPPE && p[1] == CILEN_MPPE) {
-	no.mppe = 1;
-	/*
-	 * Peer wants us to use a different strength or other setting.
-	 * Fail if we aren't willing to use his suggestion.
-	 */
-	MPPE_CI_TO_OPTS(&p[2], try.mppe);
-	if ((try.mppe & MPPE_OPT_STATEFUL) && refuse_mppe_stateful) {
-	    error("Refusing MPPE stateful mode offered by peer");
-	    try.mppe = 0;
-	} else if (((go->mppe | MPPE_OPT_STATEFUL) & try.mppe) != try.mppe) {
-	    /* Peer must have set options we didn't request (suggest) */
-	    try.mppe = 0;
-	}
+    if ((go->mppe || go->mppc || (!wo->mppe && ao->mppe)) &&
+	len >= CILEN_MPPE && p[0] == CI_MPPE && p[1] == CILEN_MPPE) {
 
-	if (!try.mppe) {
-	    error("MPPE required but peer negotiation failed");
-	    lcp_close(f->unit, "MPPE required but peer negotiation failed");
+	if (go->mppc) {
+	    no.mppc = 1;
+	    if (!(p[5] & MPPE_MPPC))
+		try.mppc = 0;
+	}
+
+	if (go->mppe)
+	    no.mppe = 1;
+	if (go->mppe_40)
+	    no.mppe_40 = 1;
+	if (go->mppe_56)
+	    no.mppe_56 = 1;
+	if (go->mppe_128)
+	    no.mppe_128 = 1;
+	if (go->mppe_stateless)
+	    no.mppe_stateless = 1;
+
+	if (ao->mppe_40) {
+	    if ((p[5] & MPPE_40BIT))
+		try.mppe_40 = 1;
+	    else
+		try.mppe_40 = (p[5] == 0) ? 1 : 0;
+	}
+	if (ao->mppe_56) {
+	    if ((p[5] & MPPE_56BIT))
+		try.mppe_56 = 1;
+	    else
+		try.mppe_56 = (p[5] == 0) ? 1 : 0;
+	}
+	if (ao->mppe_128) {
+	    if ((p[5] & MPPE_128BIT))
+		try.mppe_128 = 1;
+	    else
+		try.mppe_128 = (p[5] == 0) ? 1 : 0;
+	}
+
+	if (ao->mppe_stateless) {
+	    if ((p[2] & MPPE_STATELESS) || wo->mppe_stateless)
+		try.mppe_stateless = 1;
+	    else
+		try.mppe_stateless = 0;
+	}
+
+	if (!try.mppe_56 && !try.mppe_40 && !try.mppe_128) {
+	    try.mppe = try.mppe_stateless = 0;
+	    if (wo->mppe) {
+		/* we require encryption, but peer doesn't support it
+		   so we close connection */
+		wo->mppc = wo->mppe = wo->mppe_stateless = wo->mppe_40 =
+		    wo->mppe_56 = wo->mppe_128 = 0;
+		lcp_close(f->unit, "MPPE required but cannot negotiate MPPE "
+			  "key length");
+	    }
+        }
+	if (wo->mppe && (wo->mppe_40 != try.mppe_40) &&
+	    (wo->mppe_56 != try.mppe_56) && (wo->mppe_128 != try.mppe_128)) {
+	    /* cannot negotiate key length */
+	    wo->mppc = wo->mppe = wo->mppe_stateless = wo->mppe_40 =
+		wo->mppe_56 = wo->mppe_128 = 0;
+	    lcp_close(f->unit, "Cannot negotiate MPPE key length");
 	}
+	if (try.mppe_40 && try.mppe_56 && try.mppe_128)
+	    try.mppe_40 = try.mppe_56 = 0;
+	else
+	    if (try.mppe_56 && try.mppe_128)
+		try.mppe_56 = 0;
+	    else
+		if (try.mppe_40 && try.mppe_128)
+		    try.mppe_40 = 0;
+		else
+		    if (try.mppe_40 && try.mppe_56)
+			try.mppe_40 = 0;
+
+	p += CILEN_MPPE;
+	len -= CILEN_MPPE;
     }
 #endif /* MPPE */
+
+    if (go->lzs && len >= CILEN_LZS && p[0] == CI_LZS && p[1] == CILEN_LZS) {
+	no.lzs = 1;
+	if (((p[2]<<8)|p[3]) > 1 || (p[4] != LZS_MODE_SEQ &&
+				     p[4] != LZS_MODE_EXT))
+	    try.lzs = 0;
+	else {
+	    try.lzs_mode = p[4];
+	    try.lzs_hists = (p[2] << 8) | p[3];
+	}
+	p += CILEN_LZS;
+	len -= CILEN_LZS;
+    }
+
     if (go->deflate && len >= CILEN_DEFLATE
 	&& p[0] == (go->deflate_correct? CI_DEFLATE: CI_DEFLATE_DRAFT)
 	&& p[1] == CILEN_DEFLATE) {
@@ -1002,14 +1255,50 @@ ccp_rejci(f, p, len)
 	return -1;
 
 #ifdef MPPE
-    if (go->mppe && len >= CILEN_MPPE
+    if ((go->mppe || go->mppc) && len >= CILEN_MPPE
 	&& p[0] == CI_MPPE && p[1] == CILEN_MPPE) {
-	error("MPPE required but peer refused");
-	lcp_close(f->unit, "MPPE required but peer refused");
+	ccp_options *wo = &ccp_wantoptions[f->unit];
+	if (p[2] != (go->mppe_stateless ? MPPE_STATELESS : 0) ||
+	    p[3] != 0 ||
+	    p[4] != 0 ||
+	    p[5] != ((go->mppe_40 ? MPPE_40BIT : 0) |
+		     (go->mppe_56 ? MPPE_56BIT : 0) |
+		     (go->mppe_128 ? MPPE_128BIT : 0) |
+		     (go->mppc ? MPPE_MPPC : 0)))
+	    return 0;
+	if (go->mppc)
+	    try.mppc = 0;
+	if (go->mppe) {
+	    try.mppe = 0;
+	    if (go->mppe_40)
+		try.mppe_40 = 0;
+	    if (go->mppe_56)
+		try.mppe_56 = 0;
+	    if (go->mppe_128)
+		try.mppe_128 = 0;
+	    if (go->mppe_stateless)
+		try.mppe_stateless = 0;
+	    if (!try.mppe_56 && !try.mppe_40 && !try.mppe_128)
+		try.mppe = try.mppe_stateless = 0;
+	    if (wo->mppe) { /* we want MPPE but cannot negotiate key length */
+		wo->mppc = wo->mppe = wo->mppe_stateless = wo->mppe_40 =
+		    wo->mppe_56 = wo->mppe_128 = 0;
+		lcp_close(f->unit, "MPPE required but cannot negotiate MPPE "
+			  "key length");
+	    }
+	}
 	p += CILEN_MPPE;
 	len -= CILEN_MPPE;
     }
-#endif
+#endif /* MPPE */
+    if (go->lzs && len >= CILEN_LZS && p[0] == CI_LZS && p[1] == CILEN_LZS) {
+	if (p[2] != go->lzs_hists>>8 || p[3] != (go->lzs_hists&0xff) 
+	    || p[4] != go->lzs_mode)
+	    return 0;
+	try.lzs = 0;
+	p += CILEN_LZS;
+	len -= CILEN_LZS;
+    }
     if (go->deflate_correct && len >= CILEN_DEFLATE
 	&& p[0] == CI_DEFLATE && p[1] == CILEN_DEFLATE) {
 	if (p[2] != DEFLATE_MAKE_OPT(go->deflate_size)
@@ -1073,14 +1362,15 @@ ccp_reqci(f, p, lenp, dont_nak)
     int dont_nak;
 {
     int ret, newret, res;
-    u_char *p0, *retp;
+    u_char *p0, *retp, p2, p5;
     int len, clen, type, nb;
     ccp_options *ho = &ccp_hisoptions[f->unit];
     ccp_options *ao = &ccp_allowoptions[f->unit];
+    ccp_options *wo = &ccp_wantoptions[f->unit];
 #ifdef MPPE
-    bool rej_for_ci_mppe = 1;	/* Are we rejecting based on a bad/missing */
-				/* CI_MPPE, or due to other options?       */
-#endif
+    u_char opt_buf[CILEN_MPPE + MPPE_MAX_KEY_LEN];
+/*     int mtu; */
+#endif /* MPPE */
 
     ret = CONFACK;
     retp = p0 = p;
@@ -1103,106 +1393,302 @@ ccp_reqci(f, p, lenp, dont_nak)
 	    switch (type) {
 #ifdef MPPE
 	    case CI_MPPE:
-		if (!ao->mppe || clen != CILEN_MPPE) {
+ 		if ((!ao->mppc && !ao->mppe) || clen != CILEN_MPPE) {
 		    newret = CONFREJ;
 		    break;
 		}
-		MPPE_CI_TO_OPTS(&p[2], ho->mppe);
-
-		/* Nak if anything unsupported or unknown are set. */
-		if (ho->mppe & MPPE_OPT_UNSUPPORTED) {
-		    newret = CONFNAK;
-		    ho->mppe &= ~MPPE_OPT_UNSUPPORTED;
-		}
-		if (ho->mppe & MPPE_OPT_UNKNOWN) {
+ 		p2 = p[2];
+ 		p5 = p[5];
+ 		/* not sure what they want, tell 'em what we got */
+ 		if (((p[2] & ~MPPE_STATELESS) != 0 || p[3] != 0 || p[4] != 0 ||
+ 		     (p[5] & ~(MPPE_40BIT | MPPE_56BIT | MPPE_128BIT |
+ 			       MPPE_MPPC)) != 0 || p[5] == 0) ||
+ 		    (p[2] == 0 && p[3] == 0 && p[4] == 0 &&  p[5] == 0)) {
 		    newret = CONFNAK;
-		    ho->mppe &= ~MPPE_OPT_UNKNOWN;
-		}
-
-		/* Check state opt */
-		if (ho->mppe & MPPE_OPT_STATEFUL) {
-		    /*
-		     * We can Nak and request stateless, but it's a
-		     * lot easier to just assume the peer will request
-		     * it if he can do it; stateful mode is bad over
-		     * the Internet -- which is where we expect MPPE.
-		     */
-		   if (refuse_mppe_stateful) {
-			error("Refusing MPPE stateful mode offered by peer");
-			newret = CONFREJ;
-			break;
+ 		    p[2] = (wo->mppe_stateless ? MPPE_STATELESS : 0);
+		    p[3] = 0;
+ 		    p[4] = 0;
+ 		    p[5] = (wo->mppe_40 ? MPPE_40BIT : 0) |
+ 			(wo->mppe_56 ? MPPE_56BIT : 0) |
+ 			(wo->mppe_128 ? MPPE_128BIT : 0) |
+ 			(wo->mppc ? MPPE_MPPC : 0);
+ 		    break;
+  		}
+
+ 		if ((p[5] & MPPE_MPPC)) {
+ 		    if (ao->mppc) {
+ 			ho->mppc = 1;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			opt_buf[2] = opt_buf[3] = opt_buf[4] = 0;
+ 			opt_buf[5] = MPPE_MPPC;
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE, 1) <= 0) {
+ 			    ho->mppc = 0;
+ 			    p[5] &= ~MPPE_MPPC;
+ 			    newret = CONFNAK;
+ 			}
+ 		    } else {
+		      newret = CONFREJ;
+ 			if (wo->mppe || ao->mppe) {
+ 			    p[5] &= ~MPPE_MPPC;
+ 			    newret = CONFNAK;
+ 			}
 		    }
 		}
-
-		/* Find out which of {S,L} are set. */
-		if ((ho->mppe & MPPE_OPT_128)
-		     && (ho->mppe & MPPE_OPT_40)) {
-		    /* Both are set, negotiate the strongest. */
-		    newret = CONFNAK;
-		    if (ao->mppe & MPPE_OPT_128)
-			ho->mppe &= ~MPPE_OPT_40;
-		    else if (ao->mppe & MPPE_OPT_40)
-			ho->mppe &= ~MPPE_OPT_128;
-		    else {
-			newret = CONFREJ;
-			break;
-		    }
-		} else if (ho->mppe & MPPE_OPT_128) {
-		    if (!(ao->mppe & MPPE_OPT_128)) {
-			newret = CONFREJ;
-			break;
-		    }
-		} else if (ho->mppe & MPPE_OPT_40) {
-		    if (!(ao->mppe & MPPE_OPT_40)) {
-			newret = CONFREJ;
-			break;
-		    }
+ 		if (ao->mppe)
+ 		    ho->mppe = 1;
+ 
+ 		if ((p[2] & MPPE_STATELESS)) {
+ 		    if (ao->mppe_stateless) {
+ 			if (wo->mppe_stateless)
+ 			    ho->mppe_stateless = 1;
+ 			else {
+ 			    newret = CONFNAK;
+ 			    if (!dont_nak)
+ 				p[2] &= ~MPPE_STATELESS;
+ 			}
+ 		    } else {
+ 			newret = CONFNAK;
+ 			if (!dont_nak)
+ 			    p[2] &= ~MPPE_STATELESS;
+ 		    }
+ 		} else {
+ 		    if (wo->mppe_stateless && !dont_nak) {
+ 			wo->mppe_stateless = 0;
+ 			newret = CONFNAK;
+ 			p[2] |= MPPE_STATELESS;
+  		    }
+  		}
+  
+ 		if ((p[5] & ~MPPE_MPPC) == (MPPE_40BIT|MPPE_56BIT|MPPE_128BIT)) {
+  		    newret = CONFNAK;
+ 		    if (ao->mppe_128) {
+ 			ho->mppe_128 = 1;
+ 			p[5] &= ~(MPPE_40BIT|MPPE_56BIT);
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_128 = 0;
+ 			    p[5] |= (MPPE_40BIT|MPPE_56BIT);
+ 			    p[5] &= ~MPPE_128BIT;
+ 			    goto check_mppe_56_40;
+ 			}
+ 			goto check_mppe;
+  		    }
+ 		    p[5] &= ~MPPE_128BIT;
+ 		    goto check_mppe_56_40;
+ 		}
+ 		if ((p[5] & ~MPPE_MPPC) == (MPPE_56BIT|MPPE_128BIT)) {
+ 		    newret = CONFNAK;
+ 		    if (ao->mppe_128) {
+ 			ho->mppe_128 = 1;
+ 			p[5] &= ~MPPE_56BIT;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_128 = 0;
+ 			    p[5] |= MPPE_56BIT;
+ 			    p[5] &= ~MPPE_128BIT;
+ 			    goto check_mppe_56;
+ 			}
+ 			goto check_mppe;
+  		    }
+ 		    p[5] &= ~MPPE_128BIT;
+ 		    goto check_mppe_56;
+ 		}
+ 		if ((p[5] & ~MPPE_MPPC) == (MPPE_40BIT|MPPE_128BIT)) {
+ 		    newret = CONFNAK;
+ 		    if (ao->mppe_128) {
+ 			ho->mppe_128 = 1;
+ 			p[5] &= ~MPPE_40BIT;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_128 = 0;
+ 			    p[5] |= MPPE_40BIT;
+ 			    p[5] &= ~MPPE_128BIT;
+ 			    goto check_mppe_40;
+ 			}
+ 			goto check_mppe;
+ 		    }
+ 		    p[5] &= ~MPPE_128BIT;
+ 		    goto check_mppe_40;
+ 		}
+ 		if ((p[5] & ~MPPE_MPPC) == MPPE_128BIT) {
+ 		    if (ao->mppe_128) {
+ 			ho->mppe_128 = 1;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_128 = 0;
+ 			    p[5] &= ~MPPE_128BIT;
+ 			    newret = CONFNAK;
+ 			}
+ 			goto check_mppe;
+ 		    }
+		    p[5] &= ~MPPE_128BIT;
+ 		    newret = CONFNAK;
+ 		    goto check_mppe;
+ 		}
+ 	    check_mppe_56_40:
+		if ((p[5] & ~MPPE_MPPC) == (MPPE_40BIT|MPPE_56BIT)) {
+ 		    newret = CONFNAK;
+ 		    if (ao->mppe_56) {
+ 			ho->mppe_56 = 1;
+ 			p[5] &= ~MPPE_40BIT;
+			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_56 = 0;
+ 			    p[5] |= MPPE_40BIT;
+ 			    p[5] &= ~MPPE_56BIT;
+			    newret = CONFNAK;
+ 			    goto check_mppe_40;
+ 			}
+			goto check_mppe;
+ 		    }
+		    p[5] &= ~MPPE_56BIT;
+ 		    goto check_mppe_40;
+ 		}
+ 	    check_mppe_56:
+		if ((p[5] & ~MPPE_MPPC) == MPPE_56BIT) {
+ 		    if (ao->mppe_56) {
+ 			ho->mppe_56 = 1;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+ 			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_56 = 0;
+ 			    p[5] &= ~MPPE_56BIT;
+			    newret = CONFNAK;
+ 			}
+			goto check_mppe;
+ 		    }
+ 		    p[5] &= ~MPPE_56BIT;
+ 		    newret = CONFNAK;
+		    goto check_mppe;
+ 		}
+ 	    check_mppe_40:
+		if ((p[5] & ~MPPE_MPPC) == MPPE_40BIT) {
+ 		    if (ao->mppe_40) {
+ 			ho->mppe_40 = 1;
+ 			BCOPY(p, opt_buf, CILEN_MPPE);
+			BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
+ 			      MPPE_MAX_KEY_LEN);
+ 			if (ccp_test(f->unit, opt_buf, CILEN_MPPE +
+ 				     MPPE_MAX_KEY_LEN, 1) <= 0) {
+ 			    ho->mppe_40 = 0;
+			    p[5] &= ~MPPE_40BIT;
+ 			    newret = CONFNAK;
+ 			}
+ 			goto check_mppe;
+ 		    }
+ 		    p[5] &= ~MPPE_40BIT;
+ 		}
+ 
+ 	    check_mppe:
+ 		if (!ho->mppe_40 && !ho->mppe_56 && !ho->mppe_128) {
+ 		    if (wo->mppe_40 || wo->mppe_56 || wo->mppe_128) {
+ 			newret = CONFNAK;
+ 			p[2] |= (wo->mppe_stateless ? MPPE_STATELESS : 0);
+			p[5] |= (wo->mppe_40 ? MPPE_40BIT : 0) |
+ 			    (wo->mppe_56 ? MPPE_56BIT : 0) |
+ 			    (wo->mppe_128 ? MPPE_128BIT : 0) |
+ 			    (wo->mppc ? MPPE_MPPC : 0);
+ 		    } else {
+ 			ho->mppe = ho->mppe_stateless = 0;
+ 		    }
 		} else {
-		    /* Neither are set. */
-		    /* We cannot accept this.  */
-		    newret = CONFNAK;
-		    /* Give the peer our idea of what can be used,
-		       so it can choose and confirm */
-		    ho->mppe = ao->mppe;
-		}
-
-		/* rebuild the opts */
-		MPPE_OPTS_TO_CI(ho->mppe, &p[2]);
-		if (newret == CONFACK) {
-		    u_char opt_buf[CILEN_MPPE + MPPE_MAX_KEY_LEN];
-		    int mtu;
-
-		    BCOPY(p, opt_buf, CILEN_MPPE);
-		    BCOPY(mppe_send_key, &opt_buf[CILEN_MPPE],
-			  MPPE_MAX_KEY_LEN);
-		    if (ccp_test(f->unit, opt_buf,
-				 CILEN_MPPE + MPPE_MAX_KEY_LEN, 1) <= 0) {
-			/* This shouldn't happen, we've already tested it! */
-			error("MPPE required, but kernel has no support.");
-			lcp_close(f->unit, "MPPE required but not available");
-			newret = CONFREJ;
-			break;
-		    }
-		    /*
-		     * We need to decrease the interface MTU by MPPE_PAD
-		     * because MPPE frames **grow**.  The kernel [must]
-		     * allocate MPPE_PAD extra bytes in xmit buffers.
-		     */
-		    mtu = netif_get_mtu(f->unit);
-		    if (mtu)
-			netif_set_mtu(f->unit, mtu - MPPE_PAD);
-		    else
-			newret = CONFREJ;
-		}
-
-		/*
-		 * We have accepted MPPE or are willing to negotiate
-		 * MPPE parameters.  A CONFREJ is due to subsequent
-		 * (non-MPPE) processing.
-		 */
-		rej_for_ci_mppe = 0;
-		break;
-#endif /* MPPE */
+ 		    /* MPPE is not compatible with other compression types */
+ 		    if (wo->mppe) {
+ 			ao->bsd_compress = 0;
+ 			ao->predictor_1 = 0;
+ 			ao->predictor_2 = 0;
+			ao->deflate = 0;
+ 			ao->lzs = 0;
+ 		    }
+ 		}
+ 		if ((!ho->mppc || !ao->mppc) && !ho->mppe) {
+ 		    p[2] = p2;
+ 		    p[5] = p5;
+  		    newret = CONFREJ;
+  		    break;
+  		}
+  
+ 		/*
+ 		 * I have commented the code below because according to RFC1547
+ 		 * MTU is only information for higher level protocols about
+ 		 * "the maximum allowable length for a packet (q.v.) transmitted
+ 		 * over a point-to-point link without incurring network layer
+ 		 * fragmentation." Of course a PPP implementation should be able
+ 		 * to handle overhead added by MPPE - in our case apropriate code
+ 		 * is located in drivers/net/ppp_generic.c in the kernel sources.
+		 *
+ 		 * According to RFC1661:
+ 		 * - when negotiated MRU is less than 1500 octets, a PPP
+ 		 *   implementation must still be able to receive at least 1500
+ 		 *   octets,
+ 		 * - when PFC is negotiated, a PPP implementation is still
+ 		 *   required to receive frames with uncompressed protocol field.
+		 *
+ 		 * So why not to handle MPPE overhead without changing MTU value?
+ 		 * I am sure that RFC3078, unfortunately silently, assumes that.
+ 		 */
+ 
+ 		/*
+ 		 * We need to decrease the interface MTU by MPPE_PAD
+ 		 * because MPPE frames **grow**.  The kernel [must]
+ 		 * allocate MPPE_PAD extra bytes in xmit buffers.
+ 		 */
+ /*
+ 		mtu = netif_get_mtu(f->unit);
+ 		if (mtu) {
+ 		    netif_set_mtu(f->unit, mtu - MPPE_PAD);
+ 		} else {
+		    newret = CONFREJ;
+ 		    if (ccp_wantoptions[f->unit].mppe) {
+ 			error("Cannot adjust MTU needed by MPPE.");
+ 			lcp_close(f->unit, "Cannot adjust MTU needed by MPPE.");
+ 		    }
+ 		}
+ */
+ 		break;
+  #endif /* MPPE */
+ 
+	    case CI_LZS:
+ 		if (!ao->lzs || clen != CILEN_LZS) {
+ 		    newret = CONFREJ;
+ 		    break;
+ 		}
+ 
+ 		ho->lzs = 1;
+		ho->lzs_hists = (p[2] << 8) | p[3];
+ 		ho->lzs_mode = p[4];
+	if ((ho->lzs_hists != ao->lzs_hists) ||
+		    (ho->lzs_mode != ao->lzs_mode)) {
+ 		    newret = CONFNAK;
+ 		    if (!dont_nak) {
+ 			p[2] = ao->lzs_hists >> 8;
+ 			p[3] = ao->lzs_hists & 0xff;
+ 			p[4] = ao->lzs_mode;
+	    } else
+ 			break;
+ 		}
+ 
+ 		if (p == p0 && ccp_test(f->unit, p, CILEN_LZS, 1) <= 0) {
+ 		    newret = CONFREJ;
+ 		}
+ 		break;
 	    case CI_DEFLATE:
 	    case CI_DEFLATE_DRAFT:
 		if (!ao->deflate || clen != CILEN_DEFLATE
@@ -1344,12 +1830,6 @@ ccp_reqci(f, p, lenp, dont_nak)
 	else
 	    *lenp = retp - p0;
     }
-#ifdef MPPE
-    if (ret == CONFREJ && ao->mppe && rej_for_ci_mppe) {
-	error("MPPE required but peer negotiation failed");
-	lcp_close(f->unit, "MPPE required but peer negotiation failed");
-    }
-#endif
     return ret;
 }
 
@@ -1371,24 +1851,35 @@ method_name(opt, opt2)
 	char *p = result;
 	char *q = result + sizeof(result); /* 1 past result */
 
-	slprintf(p, q - p, "MPPE ");
-	p += 5;
-	if (opt->mppe & MPPE_OPT_128) {
-	    slprintf(p, q - p, "128-bit ");
-	    p += 8;
-	}
-	if (opt->mppe & MPPE_OPT_40) {
-	    slprintf(p, q - p, "40-bit ");
-	    p += 7;
-	}
-	if (opt->mppe & MPPE_OPT_STATEFUL)
-	    slprintf(p, q - p, "stateful");
-	else
-	    slprintf(p, q - p, "stateless");
-
+	if (opt->mppe) {
+	    if (opt->mppc) {
+		slprintf(p, q - p, "MPPC/MPPE ");
+		p += 10;
+	    } else {
+		slprintf(p, q - p, "MPPE ");
+		p += 5;
+	    }
+	    if (opt->mppe_128) {
+		slprintf(p, q - p, "128-bit ");
+		p += 8;
+	    } else if (opt->mppe_56) {
+		slprintf(p, q - p, "56-bit ");
+		p += 7;
+	    } else if (opt->mppe_40) {
+		slprintf(p, q - p, "40-bit ");
+		p += 7;
+	    }
+	    if (opt->mppe_stateless)
+		slprintf(p, q - p, "stateless");
+	    else
+		slprintf(p, q - p, "stateful");
+	} else if (opt->mppc)
+	    slprintf(p, q - p, "MPPC");
 	break;
     }
-#endif
+#endif /* MPPE */
+    case CI_LZS:
+	return "Stac LZS";
     case CI_DEFLATE:
     case CI_DEFLATE_DRAFT:
 	if (opt2 != NULL && opt2->deflate_size != opt->deflate_size)
@@ -1444,12 +1935,12 @@ ccp_up(f)
     } else if (ANY_COMPRESS(*ho))
 	notice("%s transmit compression enabled", method_name(ho, NULL));
 #ifdef MPPE
-    if (go->mppe) {
+    if (go->mppe || go->mppc) {
 	BZERO(mppe_recv_key, MPPE_MAX_KEY_LEN);
 	BZERO(mppe_send_key, MPPE_MAX_KEY_LEN);
 	continue_networks(f->unit);		/* Bring up IP et al */
     }
-#endif
+#endif /* MPPE */
 }
 
 /*
@@ -1472,7 +1963,7 @@ ccp_down(f)
 	    lcp_close(f->unit, "MPPE disabled");
 	}
     }
-#endif
+#endif /* MPPE */
 }
 
 /*
@@ -1532,24 +2023,28 @@ ccp_printpkt(p, plen, printer, arg)
 #ifdef MPPE
 	    case CI_MPPE:
 		if (optlen >= CILEN_MPPE) {
-		    u_char mppe_opts;
-
-		    MPPE_CI_TO_OPTS(&p[2], mppe_opts);
-		    printer(arg, "mppe %s %s %s %s %s %s%s",
-			    (p[2] & MPPE_H_BIT)? "+H": "-H",
-			    (p[5] & MPPE_M_BIT)? "+M": "-M",
-			    (p[5] & MPPE_S_BIT)? "+S": "-S",
-			    (p[5] & MPPE_L_BIT)? "+L": "-L",
+		    printer(arg, "mppe %s %s %s %s %s %s",
+			    (p[2] & MPPE_STATELESS)? "+H": "-H",
+			    (p[5] & MPPE_56BIT)? "+M": "-M",
+			    (p[5] & MPPE_128BIT)? "+S": "-S",
+			    (p[5] & MPPE_40BIT)? "+L": "-L",
 			    (p[5] & MPPE_D_BIT)? "+D": "-D",
-			    (p[5] & MPPE_C_BIT)? "+C": "-C",
-			    (mppe_opts & MPPE_OPT_UNKNOWN)? " +U": "");
-		    if (mppe_opts & MPPE_OPT_UNKNOWN)
+			    (p[5] & MPPE_MPPC)? "+C": "-C");
+		    if ((p[5] & ~(MPPE_56BIT | MPPE_128BIT | MPPE_40BIT |
+				  MPPE_D_BIT | MPPE_MPPC)) ||
+			(p[2] & ~MPPE_STATELESS))
 			printer(arg, " (%.2x %.2x %.2x %.2x)",
 				p[2], p[3], p[4], p[5]);
 		    p += CILEN_MPPE;
 		}
 		break;
-#endif
+#endif /* MPPE */
+	    case CI_LZS:
+		if (optlen >= CILEN_LZS) {
+		    printer(arg, "lzs %.2x %.2x %.2x", p[2], p[3], p[4]);
+		    p += CILEN_LZS;
+		}
+		break;
 	    case CI_DEFLATE:
 	    case CI_DEFLATE_DRAFT:
 		if (optlen >= CILEN_DEFLATE) {
@@ -1635,6 +2130,7 @@ ccp_datainput(unit, pkt, len)
 	    error("Lost compression sync: disabling compression");
 	    ccp_close(unit, "Lost compression sync");
 #ifdef MPPE
+	    /* My module dosn't need this. J.D., 2003-07-06 */
 	    /*
 	     * If we were doing MPPE, we must also take the link down.
 	     */
@@ -1642,9 +2138,18 @@ ccp_datainput(unit, pkt, len)
 		error("Too many MPPE errors, closing LCP");
 		lcp_close(unit, "Too many MPPE errors");
 	    }
-#endif
+#endif /* MPPE */
 	} else {
 	    /*
+	     * When LZS or MPPE/MPPC is negotiated we just send CCP_RESETREQ
+	     * and don't wait for CCP_RESETACK
+	     */
+	    if ((ccp_gotoptions[f->unit].method == CI_LZS) ||
+		(ccp_gotoptions[f->unit].method == CI_MPPE)) {
+		fsm_sdata(f, CCP_RESETREQ, f->reqid = ++f->id, NULL, 0);
+		return;
+	    }
+	    /*
 	     * Send a reset-request to reset the peer's compressor.
 	     * We don't do that if we are still waiting for an
 	     * acknowledgement to a previous reset-request.
--- a/pppd/ccp.h
+++ b/pppd/ccp.h
@@ -37,9 +37,17 @@ typedef struct ccp_options {
     bool predictor_2;		/* do Predictor-2? */
     bool deflate_correct;	/* use correct code for deflate? */
     bool deflate_draft;		/* use draft RFC code for deflate? */
+    bool lzs;			/* do Stac LZS? */
+    bool mppc;			/* do MPPC? */
     bool mppe;			/* do MPPE? */
+    bool mppe_40;		/* allow 40 bit encryption? */
+    bool mppe_56;		/* allow 56 bit encryption? */
+    bool mppe_128;		/* allow 128 bit encryption? */
+    bool mppe_stateless;	/* allow stateless encryption */
     u_short bsd_bits;		/* # bits/code for BSD Compress */
     u_short deflate_size;	/* lg(window size) for Deflate */
+    u_short lzs_mode;		/* LZS check mode */
+    u_short lzs_hists;		/* number of LZS histories */
     short method;		/* code for chosen compression method */
 } ccp_options;
 
--- a/pppd/chap_ms.c
+++ b/pppd/chap_ms.c
@@ -963,13 +963,17 @@ set_mppe_enc_types(int policy, int types
     /*
      * Disable undesirable encryption types.  Note that we don't ENABLE
      * any encryption types, to avoid overriding manual configuration.
+     *
+     * It seems that 56 bit keys are unsupported in MS-RADIUS (see RFC 2548)
      */
     switch(types) {
 	case MPPE_ENC_TYPES_RC4_40:
-	    ccp_wantoptions[0].mppe &= ~MPPE_OPT_128;	/* disable 128-bit */
+	    ccp_wantoptions[0].mppe_128 = 0;	/* disable 128-bit */
+	    ccp_wantoptions[0].mppe_56 = 0;	/* disable 56-bit */
 	    break;
 	case MPPE_ENC_TYPES_RC4_128:
-	    ccp_wantoptions[0].mppe &= ~MPPE_OPT_40;	/* disable 40-bit */
+	    ccp_wantoptions[0].mppe_56 = 0;	/* disable 56-bit */
+	    ccp_wantoptions[0].mppe_40 = 0;	/* disable 40-bit */
 	    break;
 	default:
 	    break;
