/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  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. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>

__FBSDID("$FreeBSD$");

#ifndef lint
#if 0
static const char sccsid[] = "@(#)encrypt.c     8.2 (Berkeley) 5/30/95";
#endif
#endif /* not lint */

/*
 * Copyright (C) 1990 by the Massachusetts Institute of Technology
 *
 * Export of this software from the United States of America is assumed
 * to require a specific license from the United States Government.
 * It is the responsibility of any person or organization contemplating
 * export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#ifdef  ENCRYPTION

#include <sys/types.h>
#define ENCRYPT_NAMES
#include <arpa/telnet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "encrypt.h"
#include "misc.h"

/*
 * These functions pointers point to the current routines
 * for encrypting and decrypting data.
 */
void    (*encrypt_output)(unsigned char *, int);
int     (*decrypt_input)(int);

int EncryptType(char *type, char *mode);
int EncryptStart(char *mode);
int EncryptStop(char *mode);
int EncryptStartInput(void);
int EncryptStartOutput(void);
int EncryptStopInput(void);
int EncryptStopOutput(void);

int encrypt_debug_mode = 0;
static int decrypt_mode = 0;
static int encrypt_mode = 0;
static int encrypt_verbose = 0;
static int autoencrypt = 0;
static int autodecrypt = 0;
static int havesessionkey = 0;
static int Server = 0;
static const char *Name = "Noname";

#define typemask(x)     ((x) > 0 ? 1 << ((x)-1) : 0)

static u_long i_support_encrypt = 0
 | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
 |0;
static u_long i_support_decrypt = 0
 | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
 |0;

static u_long i_wont_support_encrypt = 0;
static u_long i_wont_support_decrypt = 0;
#define I_SUPPORT_ENCRYPT       (i_support_encrypt & ~i_wont_support_encrypt)
#define I_SUPPORT_DECRYPT       (i_support_decrypt & ~i_wont_support_decrypt)

static u_long remote_supports_encrypt = 0;
static u_long remote_supports_decrypt = 0;

static Encryptions encryptions[] = {
    { "DES_CFB64",      ENCTYPE_DES_CFB64,
                        cfb64_encrypt,
                        cfb64_decrypt,
                        cfb64_init,
                        cfb64_start,
                        cfb64_is,
                        cfb64_reply,
                        cfb64_session,
                        cfb64_keyid,
                        cfb64_printsub },
    { "DES_OFB64",      ENCTYPE_DES_OFB64,
                        ofb64_encrypt,
                        ofb64_decrypt,
                        ofb64_init,
                        ofb64_start,
                        ofb64_is,
                        ofb64_reply,
                        ofb64_session,
                        ofb64_keyid,
                        ofb64_printsub },
    { NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
};

static unsigned char str_send[64] = { IAC, SB, TELOPT_ENCRYPT,
                                         ENCRYPT_SUPPORT };
static unsigned char str_suplen = 0;
static unsigned char str_start[72] = { IAC, SB, TELOPT_ENCRYPT };
static unsigned char str_end[] = { IAC, SB, TELOPT_ENCRYPT, 0, IAC, SE };

Encryptions *
findencryption(int type)
{
        Encryptions *ep = encryptions;

        if (!(I_SUPPORT_ENCRYPT & remote_supports_decrypt & (unsigned)typemask(type)))
                return(0);
        while (ep->type && ep->type != type)
                ++ep;
        return(ep->type ? ep : 0);
}

static Encryptions *
finddecryption(int type)
{
        Encryptions *ep = encryptions;

        if (!(I_SUPPORT_DECRYPT & remote_supports_encrypt & (unsigned)typemask(type)))
                return(0);
        while (ep->type && ep->type != type)
                ++ep;
        return(ep->type ? ep : 0);
}

#define MAXKEYLEN 64

static struct key_info {
        unsigned char keyid[MAXKEYLEN];
        int keylen;
        int dir;
        int *modep;
        Encryptions *(*getcrypt)(int);
} ki[2] = {
        { { 0 }, 0, DIR_ENCRYPT, &encrypt_mode, findencryption },
        { { 0 }, 0, DIR_DECRYPT, &decrypt_mode, finddecryption },
};

static void encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len);

void
encrypt_init(const char *name, int server)
{
        Encryptions *ep = encryptions;

        Name = name;
        Server = server;
        i_support_encrypt = i_support_decrypt = 0;
        remote_supports_encrypt = remote_supports_decrypt = 0;
        encrypt_mode = 0;
        decrypt_mode = 0;
        encrypt_output = 0;
        decrypt_input = 0;

        str_suplen = 4;

        while (ep->type) {
                if (encrypt_debug_mode)
                        printf(">>>%s: I will support %s\r\n",
                                Name, ENCTYPE_NAME(ep->type));
                i_support_encrypt |= typemask(ep->type);
                i_support_decrypt |= typemask(ep->type);
                if ((i_wont_support_decrypt & typemask(ep->type)) == 0)
                        if ((str_send[str_suplen++] = ep->type) == IAC)
                                str_send[str_suplen++] = IAC;
                if (ep->init)
                        (*ep->init)(Server);
                ++ep;
        }
        str_send[str_suplen++] = IAC;
        str_send[str_suplen++] = SE;
}

static void
encrypt_list_types(void)
{
        Encryptions *ep = encryptions;

        printf("Valid encryption types:\n");
        while (ep->type) {
                printf("\t%s (%d)\r\n", ENCTYPE_NAME(ep->type), ep->type);
                ++ep;
        }
}

int
EncryptEnable(char *type, char *mode)
{
        if (isprefix(type, "help") || isprefix(type, "?")) {
                printf("Usage: encrypt enable <type> [input|output]\n");
                encrypt_list_types();
                return(0);
        }
        if (EncryptType(type, mode))
                return(EncryptStart(mode));
        return(0);
}

int
EncryptDisable(char *type, char *mode)
{
        Encryptions *ep;
        int ret = 0;

        if (isprefix(type, "help") || isprefix(type, "?")) {
                printf("Usage: encrypt disable <type> [input|output]\n");
                encrypt_list_types();
        } else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
                                                sizeof(Encryptions))) == 0) {
                printf("%s: invalid encryption type\n", type);
        } else if (Ambiguous((char **)ep)) {
                printf("Ambiguous type '%s'\n", type);
        } else {
                if ((mode == 0) || (isprefix(mode, "input") ? 1 : 0)) {
                        if (decrypt_mode == ep->type)
                                EncryptStopInput();
                        i_wont_support_decrypt |= typemask(ep->type);
                        ret = 1;
                }
                if ((mode == 0) || (isprefix(mode, "output"))) {
                        if (encrypt_mode == ep->type)
                                EncryptStopOutput();
                        i_wont_support_encrypt |= typemask(ep->type);
                        ret = 1;
                }
                if (ret == 0)
                        printf("%s: invalid encryption mode\n", mode);
        }
        return(ret);
}

int
EncryptType(char *type, char *mode)
{
        Encryptions *ep;
        int ret = 0;

        if (isprefix(type, "help") || isprefix(type, "?")) {
                printf("Usage: encrypt type <type> [input|output]\n");
                encrypt_list_types();
        } else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
                                                sizeof(Encryptions))) == 0) {
                printf("%s: invalid encryption type\n", type);
        } else if (Ambiguous((char **)ep)) {
                printf("Ambiguous type '%s'\n", type);
        } else {
                if ((mode == 0) || isprefix(mode, "input")) {
                        decrypt_mode = ep->type;
                        i_wont_support_decrypt &= ~typemask(ep->type);
                        ret = 1;
                }
                if ((mode == 0) || isprefix(mode, "output")) {
                        encrypt_mode = ep->type;
                        i_wont_support_encrypt &= ~typemask(ep->type);
                        ret = 1;
                }
                if (ret == 0)
                        printf("%s: invalid encryption mode\n", mode);
        }
        return(ret);
}

int
EncryptStart(char *mode)
{
        int ret = 0;
        if (mode) {
                if (isprefix(mode, "input"))
                        return(EncryptStartInput());
                if (isprefix(mode, "output"))
                        return(EncryptStartOutput());
                if (isprefix(mode, "help") || isprefix(mode, "?")) {
                        printf("Usage: encrypt start [input|output]\n");
                        return(0);
                }
                printf("%s: invalid encryption mode 'encrypt start ?' for help\n", mode);
                return(0);
        }
        ret += EncryptStartInput();
        ret += EncryptStartOutput();
        return(ret);
}

int
EncryptStartInput(void)
{
        if (decrypt_mode) {
                encrypt_send_request_start();
                return(1);
        }
        printf("No previous decryption mode, decryption not enabled\r\n");
        return(0);
}

int
EncryptStartOutput(void)
{
        if (encrypt_mode) {
                encrypt_start_output(encrypt_mode);
                return(1);
        }
        printf("No previous encryption mode, encryption not enabled\r\n");
        return(0);
}

int
EncryptStop(char *mode)
{
        int ret = 0;
        if (mode) {
                if (isprefix(mode, "input"))
                        return(EncryptStopInput());
                if (isprefix(mode, "output"))
                        return(EncryptStopOutput());
                if (isprefix(mode, "help") || isprefix(mode, "?")) {
                        printf("Usage: encrypt stop [input|output]\n");
                        return(0);
                }
                printf("%s: invalid encryption mode 'encrypt stop ?' for help\n", mode);
                return(0);
        }
        ret += EncryptStopInput();
        ret += EncryptStopOutput();
        return(ret);
}

int
EncryptStopInput(void)
{
        encrypt_send_request_end();
        return(1);
}

int
EncryptStopOutput(void)
{
        encrypt_send_end();
        return(1);
}

void
encrypt_display(void)
{
        if (encrypt_output)
                printf("Currently encrypting output with %s\r\n",
                        ENCTYPE_NAME(encrypt_mode));
        if (decrypt_input)
                printf("Currently decrypting input with %s\r\n",
                        ENCTYPE_NAME(decrypt_mode));
}

int
EncryptStatus(void)
{
        if (encrypt_output)
                printf("Currently encrypting output with %s\r\n",
                        ENCTYPE_NAME(encrypt_mode));
        else if (encrypt_mode) {
                printf("Currently output is clear text.\r\n");
                printf("Last encryption mode was %s\r\n",
                        ENCTYPE_NAME(encrypt_mode));
        }
        if (decrypt_input) {
                printf("Currently decrypting input with %s\r\n",
                        ENCTYPE_NAME(decrypt_mode));
        } else if (decrypt_mode) {
                printf("Currently input is clear text.\r\n");
                printf("Last decryption mode was %s\r\n",
                        ENCTYPE_NAME(decrypt_mode));
        }
        return 1;
}

void
encrypt_send_support(void)
{
        if (str_suplen) {
                /*
                 * If the user has requested that decryption start
                 * immediatly, then send a "REQUEST START" before
                 * we negotiate the type.
                 */
                if (!Server && autodecrypt)
                        encrypt_send_request_start();
                net_write(str_send, str_suplen);
                printsub('>', &str_send[2], str_suplen - 2);
                str_suplen = 0;
        }
}

int
EncryptDebug(int on)
{
        if (on < 0)
                encrypt_debug_mode ^= 1;
        else
                encrypt_debug_mode = on;
        printf("Encryption debugging %s\r\n",
                encrypt_debug_mode ? "enabled" : "disabled");
        return(1);
}

int
EncryptVerbose(int on)
{
        if (on < 0)
                encrypt_verbose ^= 1;
        else
                encrypt_verbose = on;
        printf("Encryption %s verbose\r\n",
                encrypt_verbose ? "is" : "is not");
        return(1);
}

int
EncryptAutoEnc(int on)
{
        encrypt_auto(on);
        printf("Automatic encryption of output is %s\r\n",
                autoencrypt ? "enabled" : "disabled");
        return(1);
}

int
EncryptAutoDec(int on)
{
        decrypt_auto(on);
        printf("Automatic decryption of input is %s\r\n",
                autodecrypt ? "enabled" : "disabled");
        return(1);
}

/*
 * Called when ENCRYPT SUPPORT is received.
 */
void
encrypt_support(unsigned char *typelist, int cnt)
{
        int type, use_type = 0;
        Encryptions *ep;

        /*
         * Forget anything the other side has previously told us.
         */
        remote_supports_decrypt = 0;

        while (cnt-- > 0) {
                type = *typelist++;
                if (encrypt_debug_mode)
                        printf(">>>%s: He is supporting %s (%d)\r\n",
                                Name,
                                ENCTYPE_NAME(type), type);
                if ((type < ENCTYPE_CNT) &&
                    (I_SUPPORT_ENCRYPT & typemask(type))) {
                        remote_supports_decrypt |= typemask(type);
                        if (use_type == 0)
                                use_type = type;
                }
        }
        if (use_type) {
                ep = findencryption(use_type);
                if (!ep)
                        return;
                type = ep->start ? (*ep->start)(DIR_ENCRYPT, Server) : 0;
                if (encrypt_debug_mode)
                        printf(">>>%s: (*ep->start)() returned %d\r\n",
                                        Name, type);
                if (type < 0)
                        return;
                encrypt_mode = use_type;
                if (type == 0)
                        encrypt_start_output(use_type);
        }
}

void
encrypt_is(unsigned char *data, int cnt)
{
        Encryptions *ep;
        int type, ret;

        if (--cnt < 0)
                return;
        type = *data++;
        if (type < ENCTYPE_CNT)
                remote_supports_encrypt |= typemask(type);
        if (!(ep = finddecryption(type))) {
                if (encrypt_debug_mode)
                        printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
                                Name,
                                ENCTYPE_NAME_OK(type)
                                        ? ENCTYPE_NAME(type) : "(unknown)",
                                type);
                return;
        }
        if (!ep->is) {
                if (encrypt_debug_mode)
                        printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
                                Name,
                                ENCTYPE_NAME_OK(type)
                                        ? ENCTYPE_NAME(type) : "(unknown)",
                                type);
                ret = 0;
        } else {
                ret = (*ep->is)(data, cnt);
                if (encrypt_debug_mode)
                        printf("(*ep->is)(%p, %d) returned %s(%d)\n", data, cnt,
                                (ret < 0) ? "FAIL " :
                                (ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
        }
        if (ret < 0) {
                autodecrypt = 0;
        } else {
                decrypt_mode = type;
                if (ret == 0 && autodecrypt)
                        encrypt_send_request_start();
        }
}

void
encrypt_reply(unsigned char *data, int cnt)
{
        Encryptions *ep;
        int ret, type;

        if (--cnt < 0)
                return;
        type = *data++;
        if (!(ep = findencryption(type))) {
                if (encrypt_debug_mode)
                        printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
                                Name,
                                ENCTYPE_NAME_OK(type)
                                        ? ENCTYPE_NAME(type) : "(unknown)",
                                type);
                return;
        }
        if (!ep->reply) {
                if (encrypt_debug_mode)
                        printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
                                Name,
                                ENCTYPE_NAME_OK(type)
                                        ? ENCTYPE_NAME(type) : "(unknown)",
                                type);
                ret = 0;
        } else {
                ret = (*ep->reply)(data, cnt);
                if (encrypt_debug_mode)
                        printf("(*ep->reply)(%p, %d) returned %s(%d)\n",
                                data, cnt,
                                (ret < 0) ? "FAIL " :
                                (ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
        }
        if (encrypt_debug_mode)
                printf(">>>%s: encrypt_reply returned %d\n", Name, ret);
        if (ret < 0) {
                autoencrypt = 0;
        } else {
                encrypt_mode = type;
                if (ret == 0 && autoencrypt)
                        encrypt_start_output(type);
        }
}

/*
 * Called when a ENCRYPT START command is received.
 */
void
encrypt_start(unsigned char *data __unused, int cnt __unused)
{
        Encryptions *ep;

        if (!decrypt_mode) {
                /*
                 * Something is wrong.  We should not get a START
                 * command without having already picked our
                 * decryption scheme.  Send a REQUEST-END to
                 * attempt to clear the channel...
                 */
                printf("%s: Warning, Cannot decrypt input stream!!!\r\n", Name);
                encrypt_send_request_end();
                return;
        }

        if ((ep = finddecryption(decrypt_mode))) {
                decrypt_input = ep->input;
                if (encrypt_verbose)
                        printf("[ Input is now decrypted with type %s ]\r\n",
                                ENCTYPE_NAME(decrypt_mode));
                if (encrypt_debug_mode)
                        printf(">>>%s: Start to decrypt input with type %s\r\n",
                                Name, ENCTYPE_NAME(decrypt_mode));
        } else {
                printf("%s: Warning, Cannot decrypt type %s (%d)!!!\r\n",
                                Name,
                                ENCTYPE_NAME_OK(decrypt_mode)
                                        ? ENCTYPE_NAME(decrypt_mode)
                                        : "(unknown)",
                                decrypt_mode);
                encrypt_send_request_end();
        }
}

void
encrypt_session_key( Session_Key *key, int server)
{
        Encryptions *ep = encryptions;

        havesessionkey = 1;

        while (ep->type) {
                if (ep->session)
                        (*ep->session)(key, server);
                ++ep;
        }
}

/*
 * Called when ENCRYPT END is received.
 */
void
encrypt_end(void)
{
        decrypt_input = 0;
        if (encrypt_debug_mode)
                printf(">>>%s: Input is back to clear text\r\n", Name);
        if (encrypt_verbose)
                printf("[ Input is now clear text ]\r\n");
}

/*
 * Called when ENCRYPT REQUEST-END is received.
 */
void
encrypt_request_end(void)
{
        encrypt_send_end();
}

/*
 * Called when ENCRYPT REQUEST-START is received.  If we receive
 * this before a type is picked, then that indicates that the
 * other side wants us to start encrypting data as soon as we
 * can.
 */
void
encrypt_request_start(unsigned char *data __unused, int cnt __unused)
{
        if (encrypt_mode == 0)  {
                if (Server)
                        autoencrypt = 1;
                return;
        }
        encrypt_start_output(encrypt_mode);
}

static unsigned char str_keyid[(MAXKEYLEN*2)+5] = { IAC, SB, TELOPT_ENCRYPT };

void
encrypt_enc_keyid(unsigned char *keyid, int len)
{
        encrypt_keyid(&ki[1], keyid, len);
}

void
encrypt_dec_keyid(unsigned char *keyid, int len)
{
        encrypt_keyid(&ki[0], keyid, len);
}

void
encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len)
{
        Encryptions *ep;
        int dir = kp->dir;
        int ret = 0;

        if (len > MAXKEYLEN)
                len = MAXKEYLEN;

        if (!(ep = (*kp->getcrypt)(*kp->modep))) {
                if (len == 0)
                        return;
                kp->keylen = 0;
        } else if (len == 0) {
                /*
                 * Empty option, indicates a failure.
                 */
                if (kp->keylen == 0)
                        return;
                kp->keylen = 0;
                if (ep->keyid)
                        (void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);

        } else if ((len != kp->keylen) ||
                   (memcmp(keyid, kp->keyid, len) != 0)) {
                /*
                 * Length or contents are different
                 */
                kp->keylen = len;
                memmove(kp->keyid, keyid, len);
                if (ep->keyid)
                        (void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
        } else {
                if (ep->keyid)
                        ret = (*ep->keyid)(dir, kp->keyid, &kp->keylen);
                if ((ret == 0) && (dir == DIR_ENCRYPT) && autoencrypt)
                        encrypt_start_output(*kp->modep);
                return;
        }

        encrypt_send_keyid(dir, kp->keyid, kp->keylen, 0);
}

void
encrypt_send_keyid(int dir, const char *keyid, int keylen, int saveit)
{
        unsigned char *strp;

        str_keyid[3] = (dir == DIR_ENCRYPT)
                        ? ENCRYPT_ENC_KEYID : ENCRYPT_DEC_KEYID;
        if (saveit) {
                struct key_info *kp = &ki[(dir == DIR_ENCRYPT) ? 0 : 1];
                memmove(kp->keyid, keyid, keylen);
                kp->keylen = keylen;
        }

        for (strp = &str_keyid[4]; keylen > 0; --keylen) {
                if ((*strp++ = *keyid++) == IAC)
                        *strp++ = IAC;
        }
        *strp++ = IAC;
        *strp++ = SE;
        net_write(str_keyid, strp - str_keyid);
        printsub('>', &str_keyid[2], strp - str_keyid - 2);
}

void
encrypt_auto(int on)
{
        if (on < 0)
                autoencrypt ^= 1;
        else
                autoencrypt = on ? 1 : 0;
}

void
decrypt_auto(int on)
{
        if (on < 0)
                autodecrypt ^= 1;
        else
                autodecrypt = on ? 1 : 0;
}

void
encrypt_start_output(int type)
{
        Encryptions *ep;
        unsigned char *p;
        int i;

        if (!(ep = findencryption(type))) {
                if (encrypt_debug_mode) {
                        printf(">>>%s: Can't encrypt with type %s (%d)\r\n",
                                Name,
                                ENCTYPE_NAME_OK(type)
                                        ? ENCTYPE_NAME(type) : "(unknown)",
                                type);
                }
                return;
        }
        if (ep->start) {
                i = (*ep->start)(DIR_ENCRYPT, Server);
                if (encrypt_debug_mode) {
                        printf(">>>%s: Encrypt start: %s (%d) %s\r\n",
                                Name,
                                (i < 0) ? "failed" :
                                        "initial negotiation in progress",
                                i, ENCTYPE_NAME(type));
                }
                if (i)
                        return;
        }
        p = str_start + 3;
        *p++ = ENCRYPT_START;
        for (i = 0; i < ki[0].keylen; ++i) {
                if ((*p++ = ki[0].keyid[i]) == IAC)
                        *p++ = IAC;
        }
        *p++ = IAC;
        *p++ = SE;
        net_write(str_start, p - str_start);
        net_encrypt();
        printsub('>', &str_start[2], p - &str_start[2]);
        /*
         * If we are already encrypting in some mode, then
         * encrypt the ring (which includes our request) in
         * the old mode, mark it all as "clear text" and then
         * switch to the new mode.
         */
        encrypt_output = ep->output;
        encrypt_mode = type;
        if (encrypt_debug_mode)
                printf(">>>%s: Started to encrypt output with type %s\r\n",
                        Name, ENCTYPE_NAME(type));
        if (encrypt_verbose)
                printf("[ Output is now encrypted with type %s ]\r\n",
                        ENCTYPE_NAME(type));
}

void
encrypt_send_end(void)
{
        if (!encrypt_output)
                return;

        str_end[3] = ENCRYPT_END;
        net_write(str_end, sizeof(str_end));
        net_encrypt();
        printsub('>', &str_end[2], sizeof(str_end) - 2);
        /*
         * Encrypt the output buffer now because it will not be done by
         * netflush...
         */
        encrypt_output = 0;
        if (encrypt_debug_mode)
                printf(">>>%s: Output is back to clear text\r\n", Name);
        if (encrypt_verbose)
                printf("[ Output is now clear text ]\r\n");
}

void
encrypt_send_request_start(void)
{
        unsigned char *p;
        int i;

        p = &str_start[3];
        *p++ = ENCRYPT_REQSTART;
        for (i = 0; i < ki[1].keylen; ++i) {
                if ((*p++ = ki[1].keyid[i]) == IAC)
                        *p++ = IAC;
        }
        *p++ = IAC;
        *p++ = SE;
        net_write(str_start, p - str_start);
        printsub('>', &str_start[2], p - &str_start[2]);
        if (encrypt_debug_mode)
                printf(">>>%s: Request input to be encrypted\r\n", Name);
}

void
encrypt_send_request_end(void)
{
        str_end[3] = ENCRYPT_REQEND;
        net_write(str_end, sizeof(str_end));
        printsub('>', &str_end[2], sizeof(str_end) - 2);

        if (encrypt_debug_mode)
                printf(">>>%s: Request input to be clear text\r\n", Name);
}

void
encrypt_wait(void)
{
        if (encrypt_debug_mode)
                printf(">>>%s: in encrypt_wait\r\n", Name);
        if (!havesessionkey || !(I_SUPPORT_ENCRYPT & remote_supports_decrypt))
                return;
        while (autoencrypt && !encrypt_output)
                if (telnet_spin())
                        return;
}

void
encrypt_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
{
        char tbuf[16], *cp;

        cnt -= 2;
        data += 2;
        buf[buflen-1] = '\0';
        buf[buflen-2] = '*';
        buflen -= 2;;
        for (; cnt > 0; cnt--, data++) {
                sprintf(tbuf, " %d", *data);
                for (cp = tbuf; *cp && buflen > 0; --buflen)
                        *buf++ = *cp++;
                if (buflen <= 0)
                        return;
        }
        *buf = '\0';
}

void
encrypt_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
{
        Encryptions *ep;
        int type = data[1];

        for (ep = encryptions; ep->type && ep->type != type; ep++)
                ;

        if (ep->printsub)
                (*ep->printsub)(data, cnt, buf, buflen);
        else
                encrypt_gen_printsub(data, cnt, buf, buflen);
}
#endif  /* ENCRYPTION */