text: /*
   * chap-new.c - New CHAP implementation.
   *
   * Copyright (c) 2003 Paul Mackerras. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. The name(s) of the authors of this software must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission.
   *
   * 3. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by Paul Mackerras
   *     <paulus@samba.org>".
   *
   * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
   * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
   * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
   * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
   * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include "netif/ppp/ppp_opts.h"
  #if PPP_SUPPORT && CHAP_SUPPORT  /* don't build if not configured for use in lwipopts.h */
  
  #ifndef CHAP_H
  #define CHAP_H
  
  #include "ppp.h"
  
  /*
   * CHAP packets begin with a standard header with code, id, len (2 bytes).
   */
  #define CHAP_HDRLEN	4
  
  /*
   * Values for the code field.
   */
  #define CHAP_CHALLENGE	1
  #define CHAP_RESPONSE	2
  #define CHAP_SUCCESS	3
  #define CHAP_FAILURE	4
  
  /*
   * CHAP digest codes.
   */
  #define CHAP_MD5		5
  #if MSCHAP_SUPPORT
  #define CHAP_MICROSOFT		0x80
  #define CHAP_MICROSOFT_V2	0x81
  #endif /* MSCHAP_SUPPORT */
  
  /*
   * Semi-arbitrary limits on challenge and response fields.
   */
  #define MAX_CHALLENGE_LEN	64
  #define MAX_RESPONSE_LEN	64
  
  /*
   * These limits apply to challenge and response packets we send.
   * The +4 is the +1 that we actually need rounded up.
   */
  #define CHAL_MAX_PKTLEN	(PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_CHALLENGE_LEN + MAXNAMELEN)
  #define RESP_MAX_PKTLEN	(PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_RESPONSE_LEN + MAXNAMELEN)
  
  /* bitmask of supported algorithms */
  #if MSCHAP_SUPPORT
  #define MDTYPE_MICROSOFT_V2	0x1
  #define MDTYPE_MICROSOFT	0x2
  #endif /* MSCHAP_SUPPORT */
  #define MDTYPE_MD5		0x4
  #define MDTYPE_NONE		0
  
  #if MSCHAP_SUPPORT
  /* Return the digest alg. ID for the most preferred digest type. */
  #define CHAP_DIGEST(mdtype) \
      ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
      ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \
      ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \
      0
  #else /* !MSCHAP_SUPPORT */
  #define CHAP_DIGEST(mdtype) \
      ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
      0
  #endif /* MSCHAP_SUPPORT */
  
  /* Return the bit flag (lsb set) for our most preferred digest type. */
  #define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype)
  
  /* Return the bit flag for a given digest algorithm ID. */
  #if MSCHAP_SUPPORT
  #define CHAP_MDTYPE_D(digest) \
      ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \
      ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \
      ((digest) == CHAP_MD5)? MDTYPE_MD5: \
      0
  #else /* !MSCHAP_SUPPORT */
  #define CHAP_MDTYPE_D(digest) \
      ((digest) == CHAP_MD5)? MDTYPE_MD5: \
      0
  #endif /* MSCHAP_SUPPORT */
  
  /* Can we do the requested digest? */
  #if MSCHAP_SUPPORT
  #define CHAP_CANDIGEST(mdtype, digest) \
      ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \
      ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \
      ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
      0
  #else /* !MSCHAP_SUPPORT */
  #define CHAP_CANDIGEST(mdtype, digest) \
      ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
      0
  #endif /* MSCHAP_SUPPORT */
  
  /*
   * The code for each digest type has to supply one of these.
   */
  struct chap_digest_type {
  	int code;
  
  #if PPP_SERVER
  	/*
  	 * Note: challenge and response arguments below are formatted as
  	 * a length byte followed by the actual challenge/response data.
  	 */
  	void (*generate_challenge)(ppp_pcb *pcb, unsigned char *challenge);
  	int (*verify_response)(ppp_pcb *pcb, int id, const char *name,
  		const unsigned char *secret, int secret_len,
  		const unsigned char *challenge, const unsigned char *response,
  		char *message, int message_space);
  #endif /* PPP_SERVER */
  	void (*make_response)(ppp_pcb *pcb, unsigned char *response, int id, const char *our_name,
  		const unsigned char *challenge, const char *secret, int secret_len,
  		unsigned char *priv);
  	int (*check_success)(ppp_pcb *pcb, unsigned char *pkt, int len, unsigned char *priv);
  	void (*handle_failure)(ppp_pcb *pcb, unsigned char *pkt, int len);
  };
  
  /*
   * Each interface is described by chap structure.
   */
  #if CHAP_SUPPORT
  typedef struct chap_client_state {
  	u8_t flags;
  	const char *name;
  	const struct chap_digest_type *digest;
  	unsigned char priv[64];		/* private area for digest's use */
  } chap_client_state;
  
  #if PPP_SERVER
  typedef struct chap_server_state {
  	u8_t flags;
  	u8_t id;
  	const char *name;
  	const struct chap_digest_type *digest;
  	int challenge_xmits;
  	int challenge_pktlen;
  	unsigned char challenge[CHAL_MAX_PKTLEN];
  } chap_server_state;
  #endif /* PPP_SERVER */
  #endif /* CHAP_SUPPORT */
  
  #if 0 /* UNUSED */
  /* Hook for a plugin to validate CHAP challenge */
  extern int (*chap_verify_hook)(char *name, char *ourname, int id,
  			const struct chap_digest_type *digest,
  			unsigned char *challenge, unsigned char *response,
  			char *message, int message_space);
  #endif /* UNUSED */
  
  #if PPP_SERVER
  /* Called by authentication code to start authenticating the peer. */
  extern void chap_auth_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
  #endif /* PPP_SERVER */
  
  /* Called by auth. code to start authenticating us to the peer. */
  extern void chap_auth_with_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
  
  /* Represents the CHAP protocol to the main pppd code */
  extern const struct protent chap_protent;
  
  #endif /* CHAP_H */
  #endif /* PPP_SUPPORT && CHAP_SUPPORT */
  