1 | /*
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2 | * chap-new.c - New CHAP implementation.
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3 | *
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4 | * Copyright (c) 2003 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. The name(s) of the authors of this software must not be used to
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14 | * endorse or promote products derived from this software without
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15 | * prior written permission.
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16 | *
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17 | * 3. Redistributions of any form whatsoever must retain the following
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18 | * acknowledgment:
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19 | * "This product includes software developed by Paul Mackerras
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20 | * <paulus@samba.org>".
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21 | *
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22 | * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
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23 | * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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24 | * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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25 | * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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26 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
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27 | * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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28 | * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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29 | */
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30 |
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31 | #include "netif/ppp/ppp_opts.h"
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32 | #if PPP_SUPPORT && CHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
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33 |
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34 | #ifndef CHAP_H
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35 | #define CHAP_H
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36 |
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37 | #include "ppp.h"
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38 |
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39 | #ifdef __cplusplus
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40 | extern "C" {
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41 | #endif
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42 |
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43 | /*
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44 | * CHAP packets begin with a standard header with code, id, len (2 bytes).
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45 | */
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46 | #define CHAP_HDRLEN 4
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47 |
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48 | /*
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49 | * Values for the code field.
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50 | */
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51 | #define CHAP_CHALLENGE 1
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52 | #define CHAP_RESPONSE 2
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53 | #define CHAP_SUCCESS 3
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54 | #define CHAP_FAILURE 4
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55 |
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56 | /*
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57 | * CHAP digest codes.
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58 | */
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59 | #define CHAP_MD5 5
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60 | #if MSCHAP_SUPPORT
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61 | #define CHAP_MICROSOFT 0x80
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62 | #define CHAP_MICROSOFT_V2 0x81
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63 | #endif /* MSCHAP_SUPPORT */
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64 |
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65 | /*
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66 | * Semi-arbitrary limits on challenge and response fields.
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67 | */
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68 | #define MAX_CHALLENGE_LEN 64
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69 | #define MAX_RESPONSE_LEN 64
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70 |
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71 | /*
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72 | * These limits apply to challenge and response packets we send.
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73 | * The +4 is the +1 that we actually need rounded up.
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74 | */
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75 | #define CHAL_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_CHALLENGE_LEN + MAXNAMELEN)
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76 | #define RESP_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_RESPONSE_LEN + MAXNAMELEN)
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77 |
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78 | /* bitmask of supported algorithms */
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79 | #if MSCHAP_SUPPORT
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80 | #define MDTYPE_MICROSOFT_V2 0x1
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81 | #define MDTYPE_MICROSOFT 0x2
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82 | #endif /* MSCHAP_SUPPORT */
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83 | #define MDTYPE_MD5 0x4
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84 | #define MDTYPE_NONE 0
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85 |
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86 | #if MSCHAP_SUPPORT
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87 | /* Return the digest alg. ID for the most preferred digest type. */
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88 | #define CHAP_DIGEST(mdtype) \
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89 | ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
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90 | ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \
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91 | ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \
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92 | 0
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93 | #else /* !MSCHAP_SUPPORT */
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94 | #define CHAP_DIGEST(mdtype) \
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95 | ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
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96 | 0
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97 | #endif /* MSCHAP_SUPPORT */
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98 |
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99 | /* Return the bit flag (lsb set) for our most preferred digest type. */
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100 | #define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype)
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101 |
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102 | /* Return the bit flag for a given digest algorithm ID. */
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103 | #if MSCHAP_SUPPORT
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104 | #define CHAP_MDTYPE_D(digest) \
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105 | ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \
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106 | ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \
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107 | ((digest) == CHAP_MD5)? MDTYPE_MD5: \
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108 | 0
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109 | #else /* !MSCHAP_SUPPORT */
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110 | #define CHAP_MDTYPE_D(digest) \
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111 | ((digest) == CHAP_MD5)? MDTYPE_MD5: \
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112 | 0
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113 | #endif /* MSCHAP_SUPPORT */
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114 |
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115 | /* Can we do the requested digest? */
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116 | #if MSCHAP_SUPPORT
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117 | #define CHAP_CANDIGEST(mdtype, digest) \
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118 | ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \
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119 | ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \
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120 | ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
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121 | 0
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122 | #else /* !MSCHAP_SUPPORT */
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123 | #define CHAP_CANDIGEST(mdtype, digest) \
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124 | ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
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125 | 0
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126 | #endif /* MSCHAP_SUPPORT */
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127 |
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128 | /*
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129 | * The code for each digest type has to supply one of these.
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130 | */
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131 | struct chap_digest_type {
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132 | int code;
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133 |
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134 | #if PPP_SERVER
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135 | /*
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136 | * Note: challenge and response arguments below are formatted as
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137 | * a length byte followed by the actual challenge/response data.
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138 | */
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139 | void (*generate_challenge)(ppp_pcb *pcb, unsigned char *challenge);
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140 | int (*verify_response)(ppp_pcb *pcb, int id, const char *name,
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141 | const unsigned char *secret, int secret_len,
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142 | const unsigned char *challenge, const unsigned char *response,
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143 | char *message, int message_space);
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144 | #endif /* PPP_SERVER */
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145 | void (*make_response)(ppp_pcb *pcb, unsigned char *response, int id, const char *our_name,
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146 | const unsigned char *challenge, const char *secret, int secret_len,
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147 | unsigned char *priv);
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148 | int (*check_success)(ppp_pcb *pcb, unsigned char *pkt, int len, unsigned char *priv);
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149 | void (*handle_failure)(ppp_pcb *pcb, unsigned char *pkt, int len);
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150 | };
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151 |
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152 | /*
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153 | * Each interface is described by chap structure.
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154 | */
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155 | #if CHAP_SUPPORT
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156 | typedef struct chap_client_state {
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157 | u8_t flags;
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158 | const char *name;
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159 | const struct chap_digest_type *digest;
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160 | unsigned char priv[64]; /* private area for digest's use */
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161 | } chap_client_state;
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162 |
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163 | #if PPP_SERVER
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164 | typedef struct chap_server_state {
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165 | u8_t flags;
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166 | u8_t id;
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167 | const char *name;
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168 | const struct chap_digest_type *digest;
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169 | int challenge_xmits;
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170 | int challenge_pktlen;
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171 | unsigned char challenge[CHAL_MAX_PKTLEN];
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172 | } chap_server_state;
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173 | #endif /* PPP_SERVER */
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174 | #endif /* CHAP_SUPPORT */
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175 |
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176 | #if 0 /* UNUSED */
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177 | /* Hook for a plugin to validate CHAP challenge */
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178 | extern int (*chap_verify_hook)(char *name, char *ourname, int id,
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179 | const struct chap_digest_type *digest,
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180 | unsigned char *challenge, unsigned char *response,
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181 | char *message, int message_space);
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182 | #endif /* UNUSED */
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183 |
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184 | #if PPP_SERVER
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185 | /* Called by authentication code to start authenticating the peer. */
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186 | extern void chap_auth_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
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187 | #endif /* PPP_SERVER */
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188 |
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189 | /* Called by auth. code to start authenticating us to the peer. */
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190 | extern void chap_auth_with_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
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191 |
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192 | /* Represents the CHAP protocol to the main pppd code */
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193 | extern const struct protent chap_protent;
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194 |
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195 | #ifdef __cplusplus
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196 | }
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197 | #endif
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198 |
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199 | #endif /* CHAP_H */
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200 | #endif /* PPP_SUPPORT && CHAP_SUPPORT */
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