1 | /*
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2 | * mppe.h - Definitions for MPPE
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3 | *
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4 | * Copyright (c) 2008 Paul Mackerras. All rights reserved.
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5 | *
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6 | * Redistribution and use in source and binary forms, with or without
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7 | * modification, are permitted provided that the following conditions
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8 | * are met:
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9 | *
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10 | * 1. Redistributions of source code must retain the above copyright
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11 | * notice, this list of conditions and the following disclaimer.
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12 | *
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13 | * 2. Redistributions in binary form must reproduce the above copyright
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14 | * notice, this list of conditions and the following disclaimer in
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15 | * the documentation and/or other materials provided with the
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16 | * distribution.
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17 | *
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18 | * 3. The name(s) of the authors of this software must not be used to
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19 | * endorse or promote products derived from this software without
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20 | * prior written permission.
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21 | *
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22 | * 4. Redistributions of any form whatsoever must retain the following
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23 | * acknowledgment:
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24 | * "This product includes software developed by Paul Mackerras
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25 | * <paulus@samba.org>".
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26 | *
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27 | * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
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28 | * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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29 | * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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30 | * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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31 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
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32 | * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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33 | * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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34 | */
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35 |
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36 | #include "netif/ppp/ppp_opts.h"
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37 | #if PPP_SUPPORT && MPPE_SUPPORT /* don't build if not configured for use in lwipopts.h */
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38 |
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39 | #ifndef MPPE_H
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40 | #define MPPE_H
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41 |
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42 | #include "netif/ppp/pppcrypt.h"
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43 |
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44 | #ifdef __cplusplus
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45 | extern "C" {
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46 | #endif
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47 |
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48 | #define MPPE_PAD 4 /* MPPE growth per frame */
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49 | #define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
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50 |
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51 | /* option bits for ccp_options.mppe */
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52 | #define MPPE_OPT_40 0x01 /* 40 bit */
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53 | #define MPPE_OPT_128 0x02 /* 128 bit */
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54 | #define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
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55 | /* unsupported opts */
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56 | #define MPPE_OPT_56 0x08 /* 56 bit */
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57 | #define MPPE_OPT_MPPC 0x10 /* MPPC compression */
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58 | #define MPPE_OPT_D 0x20 /* Unknown */
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59 | #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
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60 | #define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
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61 |
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62 | /*
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63 | * This is not nice ... the alternative is a bitfield struct though.
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64 | * And unfortunately, we cannot share the same bits for the option
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65 | * names above since C and H are the same bit. We could do a u_int32
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66 | * but then we have to do a lwip_htonl() all the time and/or we still need
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67 | * to know which octet is which.
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68 | */
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69 | #define MPPE_C_BIT 0x01 /* MPPC */
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70 | #define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
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71 | #define MPPE_L_BIT 0x20 /* 40-bit */
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72 | #define MPPE_S_BIT 0x40 /* 128-bit */
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73 | #define MPPE_M_BIT 0x80 /* 56-bit, not supported */
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74 | #define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
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75 |
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76 | /* Does not include H bit; used for least significant octet only. */
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77 | #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
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78 |
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79 | /* Build a CI from mppe opts (see RFC 3078) */
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80 | #define MPPE_OPTS_TO_CI(opts, ci) \
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81 | do { \
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82 | u_char *ptr = ci; /* u_char[4] */ \
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83 | \
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84 | /* H bit */ \
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85 | if (opts & MPPE_OPT_STATEFUL) \
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86 | *ptr++ = 0x0; \
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87 | else \
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88 | *ptr++ = MPPE_H_BIT; \
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89 | *ptr++ = 0; \
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90 | *ptr++ = 0; \
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91 | \
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92 | /* S,L bits */ \
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93 | *ptr = 0; \
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94 | if (opts & MPPE_OPT_128) \
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95 | *ptr |= MPPE_S_BIT; \
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96 | if (opts & MPPE_OPT_40) \
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97 | *ptr |= MPPE_L_BIT; \
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98 | /* M,D,C bits not supported */ \
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99 | } while (/* CONSTCOND */ 0)
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100 |
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101 | /* The reverse of the above */
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102 | #define MPPE_CI_TO_OPTS(ci, opts) \
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103 | do { \
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104 | const u_char *ptr = ci; /* u_char[4] */ \
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105 | \
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106 | opts = 0; \
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107 | \
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108 | /* H bit */ \
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109 | if (!(ptr[0] & MPPE_H_BIT)) \
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110 | opts |= MPPE_OPT_STATEFUL; \
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111 | \
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112 | /* S,L bits */ \
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113 | if (ptr[3] & MPPE_S_BIT) \
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114 | opts |= MPPE_OPT_128; \
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115 | if (ptr[3] & MPPE_L_BIT) \
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116 | opts |= MPPE_OPT_40; \
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117 | \
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118 | /* M,D,C bits */ \
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119 | if (ptr[3] & MPPE_M_BIT) \
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120 | opts |= MPPE_OPT_56; \
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121 | if (ptr[3] & MPPE_D_BIT) \
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122 | opts |= MPPE_OPT_D; \
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123 | if (ptr[3] & MPPE_C_BIT) \
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124 | opts |= MPPE_OPT_MPPC; \
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125 | \
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126 | /* Other bits */ \
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127 | if (ptr[0] & ~MPPE_H_BIT) \
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128 | opts |= MPPE_OPT_UNKNOWN; \
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129 | if (ptr[1] || ptr[2]) \
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130 | opts |= MPPE_OPT_UNKNOWN; \
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131 | if (ptr[3] & ~MPPE_ALL_BITS) \
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132 | opts |= MPPE_OPT_UNKNOWN; \
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133 | } while (/* CONSTCOND */ 0)
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134 |
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135 | /* Shared MPPE padding between MSCHAP and MPPE */
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136 | #define SHA1_PAD_SIZE 40
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137 |
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138 | static const u8_t mppe_sha1_pad1[SHA1_PAD_SIZE] = {
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139 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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140 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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141 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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142 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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143 | };
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144 | static const u8_t mppe_sha1_pad2[SHA1_PAD_SIZE] = {
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145 | 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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146 | 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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147 | 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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148 | 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
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149 | };
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150 |
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151 | /*
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152 | * State for an MPPE (de)compressor.
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153 | */
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154 | typedef struct ppp_mppe_state {
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155 | lwip_arc4_context arc4;
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156 | u8_t master_key[MPPE_MAX_KEY_LEN];
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157 | u8_t session_key[MPPE_MAX_KEY_LEN];
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158 | u8_t keylen; /* key length in bytes */
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159 | /* NB: 128-bit == 16, 40-bit == 8!
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160 | * If we want to support 56-bit, the unit has to change to bits
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161 | */
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162 | u8_t bits; /* MPPE control bits */
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163 | u16_t ccount; /* 12-bit coherency count (seqno) */
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164 | u16_t sanity_errors; /* take down LCP if too many */
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165 | unsigned int stateful :1; /* stateful mode flag */
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166 | unsigned int discard :1; /* stateful mode packet loss flag */
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167 | } ppp_mppe_state;
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168 |
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169 | void mppe_set_key(ppp_pcb *pcb, ppp_mppe_state *state, u8_t *key);
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170 | void mppe_init(ppp_pcb *pcb, ppp_mppe_state *state, u8_t options);
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171 | void mppe_comp_reset(ppp_pcb *pcb, ppp_mppe_state *state);
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172 | err_t mppe_compress(ppp_pcb *pcb, ppp_mppe_state *state, struct pbuf **pb, u16_t protocol);
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173 | void mppe_decomp_reset(ppp_pcb *pcb, ppp_mppe_state *state);
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174 | err_t mppe_decompress(ppp_pcb *pcb, ppp_mppe_state *state, struct pbuf **pb);
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175 |
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176 | #ifdef __cplusplus
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177 | }
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178 | #endif
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179 |
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180 | #endif /* MPPE_H */
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181 | #endif /* PPP_SUPPORT && MPPE_SUPPORT */
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