/*
* Copyright (c) 2004 - Michael Richardson <[email protected]>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

/* \summary: Extensible Authentication Protocol (EAP) printer */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-eap.c,v 1.9 2024/09/02 16:15:31 christos Exp $");
#endif

#include <config.h>

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "extract.h"

#define EAP_FRAME_TYPE_PACKET           0
#define EAP_FRAME_TYPE_START            1
#define EAP_FRAME_TYPE_LOGOFF           2
#define EAP_FRAME_TYPE_KEY              3
#define EAP_FRAME_TYPE_ENCAP_ASF_ALERT  4

struct eap_frame_t {
   nd_uint8_t  version;
   nd_uint8_t  type;
   nd_uint16_t length;
};

static const struct tok eap_frame_type_values[] = {
   { EAP_FRAME_TYPE_PACKET,            "EAP packet" },
   { EAP_FRAME_TYPE_START,             "EAPOL start" },
   { EAP_FRAME_TYPE_LOGOFF,            "EAPOL logoff" },
   { EAP_FRAME_TYPE_KEY,               "EAPOL key" },
   { EAP_FRAME_TYPE_ENCAP_ASF_ALERT,   "Encapsulated ASF alert" },
   { 0, NULL}
};

/* RFC 3748 */
struct eap_packet_t {
   nd_uint8_t  code;
   nd_uint8_t  id;
   nd_uint16_t length;
};

#define         EAP_REQUEST     1
#define         EAP_RESPONSE    2
#define         EAP_SUCCESS     3
#define         EAP_FAILURE     4

static const struct tok eap_code_values[] = {
   { EAP_REQUEST,      "Request" },
   { EAP_RESPONSE,     "Response" },
   { EAP_SUCCESS,      "Success" },
   { EAP_FAILURE,      "Failure" },
   { 0, NULL}
};

#define         EAP_TYPE_NO_PROPOSED    0
#define         EAP_TYPE_IDENTITY       1
#define         EAP_TYPE_NOTIFICATION   2
#define         EAP_TYPE_NAK            3
#define         EAP_TYPE_MD5_CHALLENGE  4
#define         EAP_TYPE_OTP            5
#define         EAP_TYPE_GTC            6
#define         EAP_TYPE_TLS            13              /* RFC 5216 */
#define         EAP_TYPE_SIM            18              /* RFC 4186 */
#define         EAP_TYPE_TTLS           21              /* RFC 5281, draft-funk-eap-ttls-v0-01.txt */
#define         EAP_TYPE_AKA            23              /* RFC 4187 */
#define         EAP_TYPE_FAST           43              /* RFC 4851 */
#define         EAP_TYPE_EXPANDED_TYPES 254
#define         EAP_TYPE_EXPERIMENTAL   255

static const struct tok eap_type_values[] = {
   { EAP_TYPE_NO_PROPOSED,     "No proposed" },
   { EAP_TYPE_IDENTITY,        "Identity" },
   { EAP_TYPE_NOTIFICATION,    "Notification" },
   { EAP_TYPE_NAK,             "Nak" },
   { EAP_TYPE_MD5_CHALLENGE,   "MD5-challenge" },
   { EAP_TYPE_OTP,             "OTP" },
   { EAP_TYPE_GTC,             "GTC" },
   { EAP_TYPE_TLS,             "TLS" },
   { EAP_TYPE_SIM,             "SIM" },
   { EAP_TYPE_TTLS,            "TTLS" },
   { EAP_TYPE_AKA,             "AKA" },
   { EAP_TYPE_FAST,            "FAST" },
   { EAP_TYPE_EXPANDED_TYPES,  "Expanded types" },
   { EAP_TYPE_EXPERIMENTAL,    "Experimental" },
   { 0, NULL}
};

#define EAP_TLS_EXTRACT_BIT_L(x)        (((x)&0x80)>>7)

/* RFC 5216 - EAP TLS bits */
#define EAP_TLS_FLAGS_LEN_INCLUDED              (1 << 7)
#define EAP_TLS_FLAGS_MORE_FRAGMENTS            (1 << 6)
#define EAP_TLS_FLAGS_START                     (1 << 5)

static const struct tok eap_tls_flags_values[] = {
       { EAP_TLS_FLAGS_LEN_INCLUDED, "L bit" },
       { EAP_TLS_FLAGS_MORE_FRAGMENTS, "More fragments bit"},
       { EAP_TLS_FLAGS_START, "Start bit"},
       { 0, NULL}
};

#define EAP_TTLS_VERSION(x)             ((x)&0x07)

/* EAP-AKA and EAP-SIM - RFC 4187 */
#define EAP_AKA_CHALLENGE               1
#define EAP_AKA_AUTH_REJECT             2
#define EAP_AKA_SYNC_FAILURE            4
#define EAP_AKA_IDENTITY                5
#define EAP_SIM_START                   10
#define EAP_SIM_CHALLENGE               11
#define EAP_AKA_NOTIFICATION            12
#define EAP_AKA_REAUTH                  13
#define EAP_AKA_CLIENT_ERROR            14

static const struct tok eap_aka_subtype_values[] = {
   { EAP_AKA_CHALLENGE,        "Challenge" },
   { EAP_AKA_AUTH_REJECT,      "Auth reject" },
   { EAP_AKA_SYNC_FAILURE,     "Sync failure" },
   { EAP_AKA_IDENTITY,         "Identity" },
   { EAP_SIM_START,            "Start" },
   { EAP_SIM_CHALLENGE,        "Challenge" },
   { EAP_AKA_NOTIFICATION,     "Notification" },
   { EAP_AKA_REAUTH,           "Reauth" },
   { EAP_AKA_CLIENT_ERROR,     "Client error" },
   { 0, NULL}
};

/*
* Print EAP requests / responses
*/
void
eap_print(netdissect_options *ndo,
         const u_char *cp,
         u_int length)
{
   u_int type, subtype, len;
   u_int count;
   const char *sep;

   ndo->ndo_protocol = "eap";
   type = GET_U_1(cp);
   len = GET_BE_U_2(cp + 2);
   if (len != length) {
       /*
        * Probably a fragment; in some cases the fragmentation might
        * not put an EAP header on every packet, if reassembly can
        * be done without that (e.g., fragmentation to make a message
        * fit in multiple TLVs in a RADIUS packet).
        */
       ND_PRINT("EAP fragment?");
       return;
   }
   ND_PRINT("%s (%u), id %u, len %u",
           tok2str(eap_code_values, "unknown", type),
           type,
           GET_U_1((cp + 1)),
           len);
   if (len < 4) {
       ND_PRINT(" (too short for EAP header)");
       return;
   }

   ND_TCHECK_LEN(cp, len);

   if (type == EAP_REQUEST || type == EAP_RESPONSE) {
       /* RFC 3748 Section 4.1 */
       if (len < 5) {
           ND_PRINT(" (too short for EAP request/response)");
           return;
       }
       subtype = GET_U_1(cp + 4);
       ND_PRINT("\n\t\t Type %s (%u)",
               tok2str(eap_type_values, "unknown", subtype),
               subtype);

       switch (subtype) {
           case EAP_TYPE_IDENTITY:
               /* According to RFC 3748, the message is optional */
               if (len > 5) {
                   ND_PRINT(", Identity: ");
                   nd_printjnp(ndo, cp + 5, len - 5);
               }
               break;

           case EAP_TYPE_NOTIFICATION:
               /* According to RFC 3748, there must be at least one octet of message */
               if (len < 6) {
                   ND_PRINT(" (too short for EAP Notification request/response)");
                   return;
               }
               ND_PRINT(", Notification: ");
               nd_printjnp(ndo, cp + 5, len - 5);
               break;

           case EAP_TYPE_NAK:
               /*
                * one or more octets indicating
                * the desired authentication
                * type one octet per type
                */
               if (len < 6) {
                   ND_PRINT(" (too short for EAP Legacy NAK request/response)");
                   return;
               }
               sep = "";
               for (count = 5; count < len; count++) {
                   ND_PRINT("%s %s (%u)", sep,
                          tok2str(eap_type_values, "unknown", GET_U_1((cp + count))),
                          GET_U_1(cp + count));
                   sep = ",";
               }
               break;

           case EAP_TYPE_TTLS:
           case EAP_TYPE_TLS:
               if (len < 6) {
                   ND_PRINT(" (too short for EAP TLS/TTLS request/response)");
                   return;
               }
               if (subtype == EAP_TYPE_TTLS)
                   ND_PRINT(" TTLSv%u",
                          EAP_TTLS_VERSION(GET_U_1((cp + 5))));
               ND_PRINT(" flags [%s] 0x%02x",
                      bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
                      GET_U_1(cp + 5));

               if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
                   if (len < 10) {
                       ND_PRINT(" (too short for EAP TLS/TTLS request/response with length)");
                       return;
                   }
                   ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
               }
               break;

           case EAP_TYPE_FAST:
               if (len < 6) {
                   ND_PRINT(" (too short for EAP FAST request/response)");
                   return;
               }
               ND_PRINT(" FASTv%u",
                      EAP_TTLS_VERSION(GET_U_1((cp + 5))));
               ND_PRINT(" flags [%s] 0x%02x",
                      bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
                      GET_U_1(cp + 5));

               if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
                   if (len < 10) {
                       ND_PRINT(" (too short for EAP FAST request/response with length)");
                       return;
                   }
                   ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
               }

               /* FIXME - TLV attributes follow */
               break;

           case EAP_TYPE_AKA:
           case EAP_TYPE_SIM:
               if (len < 6) {
                   ND_PRINT(" (too short for EAP SIM/AKA request/response)");
                   return;
               }
               ND_PRINT(" subtype [%s] 0x%02x",
                      tok2str(eap_aka_subtype_values, "unknown", GET_U_1((cp + 5))),
                      GET_U_1(cp + 5));

               /* FIXME - TLV attributes follow */
               break;

           case EAP_TYPE_MD5_CHALLENGE:
           case EAP_TYPE_OTP:
           case EAP_TYPE_GTC:
           case EAP_TYPE_EXPANDED_TYPES:
           case EAP_TYPE_EXPERIMENTAL:
           default:
               break;
       }
   }
   return;
trunc:
   nd_print_trunc(ndo);
}

void
eapol_print(netdissect_options *ndo,
           const u_char *cp)
{
   const struct eap_frame_t *eap;
   u_int eap_type, eap_len;

   ndo->ndo_protocol = "eap";
   eap = (const struct eap_frame_t *)cp;
   ND_TCHECK_SIZE(eap);
   eap_type = GET_U_1(eap->type);

   ND_PRINT("%s (%u) v%u, len %u",
          tok2str(eap_frame_type_values, "unknown", eap_type),
          eap_type,
          GET_U_1(eap->version),
          GET_BE_U_2(eap->length));
   if (ndo->ndo_vflag < 1)
       return;

   cp += sizeof(struct eap_frame_t);
   eap_len = GET_BE_U_2(eap->length);

   switch (eap_type) {
   case EAP_FRAME_TYPE_PACKET:
       if (eap_len == 0)
           goto trunc;
       ND_PRINT(", ");
       eap_print(ndo, cp, eap_len);
       return;
   case EAP_FRAME_TYPE_LOGOFF:
   case EAP_FRAME_TYPE_ENCAP_ASF_ALERT:
   default:
       break;
   }
   return;

trunc:
   nd_print_trunc(ndo);
}

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