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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;
@@ -680,7 +815,8 @@ ccp_cilen(f)
        + (go->deflate && go->deflate_draft? 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);
 }
 
 /*
@@ -694,6 +830,8 @@ 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;
 
     /*
@@ -702,22 +840,43 @@ 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;
@@ -803,7 +962,7 @@ 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)
@@ -812,24 +971,44 @@ 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)
@@ -902,6 +1081,8 @@ 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 */
 
@@ -909,28 +1090,100 @@ 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) {
@@ -1003,14 +1256,50 @@ 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)
@@ -1074,14 +1363,15 @@ 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;
@@ -1104,106 +1394,302 @@ 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
@@ -1345,12 +1831,6 @@ 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;
 }
 
@@ -1372,24 +1852,35 @@ 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)
@@ -1445,12 +1936,12 @@ 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 */
 }
 
 /*
@@ -1473,7 +1964,7 @@ ccp_down(f)
            lcp_close(f->unit, "MPPE disabled");
        }
     }
-#endif
+#endif /* MPPE */
 }
 
 /*
@@ -1533,24 +2024,28 @@ 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) {
@@ -1636,6 +2131,7 @@ 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.
             */
@@ -1643,9 +2139,18 @@ 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? */
     u_char mppe;               /* MPPE bitfield */
+    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;