/*      NetBSD: print-telnet.c,v 1.2 1999/10/11 12:40:12 sjg Exp        */

/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Simon J. Gerraty.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
*      @(#)Copyright (c) 1994, Simon J. Gerraty.
*
*      This is free software.  It comes with NO WARRANTY.
*      Permission to use, modify and distribute this source code
*      is granted subject to the following conditions.
*      1/ that the above copyright notice and this notice
*      are preserved in all copies.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-telnet.c,v 1.10 2024/09/02 16:15:33 christos Exp $");
#endif

/* \summary: Telnet option printer */

#include <config.h>

#include "netdissect-stdinc.h"

#include <stdio.h>

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


/*      NetBSD: telnet.h,v 1.9 2001/06/11 01:50:50 wiz Exp      */

/*
* Definitions for the TELNET protocol.
*/
#define IAC     255             /* interpret as command: */
#define DONT    254             /* you are not to use option */
#define DO      253             /* please, you use option */
#define WONT    252             /* I won't use option */
#define WILL    251             /* I will use option */
#define SB      250             /* interpret as subnegotiation */
#define GA      249             /* you may reverse the line */
#define EL      248             /* erase the current line */
#define EC      247             /* erase the current character */
#define AYT     246             /* are you there */
#define AO      245             /* abort output--but let prog finish */
#define IP      244             /* interrupt process--permanently */
#define BREAK   243             /* break */
#define DM      242             /* data mark--for connect. cleaning */
#define NOP     241             /* nop */
#define SE      240             /* end sub negotiation */
#define EOR     239             /* end of record (transparent mode) */
#define ABORT   238             /* Abort process */
#define SUSP    237             /* Suspend process */
#define xEOF    236             /* End of file: EOF is already used... */

#define SYNCH   242             /* for telfunc calls */

static const char *telcmds[] = {
       "EOF", "SUSP", "ABORT", "EOR",
       "SE", "NOP", "DMARK", "BRK", "IP", "AO", "AYT", "EC",
       "EL", "GA", "SB", "WILL", "WONT", "DO", "DONT", "IAC", 0,
};

#define TELCMD_FIRST    xEOF
#define TELCMD_LAST     IAC
#define TELCMD_OK(x)    ((unsigned int)(x) <= TELCMD_LAST && \
                        (unsigned int)(x) >= TELCMD_FIRST)
#define TELCMD(x)       telcmds[(x)-TELCMD_FIRST]

/* telnet options */
#define TELOPT_BINARY   0       /* 8-bit data path */
#define TELOPT_ECHO     1       /* echo */
#define TELOPT_RCP      2       /* prepare to reconnect */
#define TELOPT_SGA      3       /* suppress go ahead */
#define TELOPT_NAMS     4       /* approximate message size */
#define TELOPT_STATUS   5       /* give status */
#define TELOPT_TM       6       /* timing mark */
#define TELOPT_RCTE     7       /* remote controlled transmission and echo */
#define TELOPT_NAOL     8       /* negotiate about output line width */
#define TELOPT_NAOP     9       /* negotiate about output page size */
#define TELOPT_NAOCRD   10      /* negotiate about CR disposition */
#define TELOPT_NAOHTS   11      /* negotiate about horizontal tabstops */
#define TELOPT_NAOHTD   12      /* negotiate about horizontal tab disposition */
#define TELOPT_NAOFFD   13      /* negotiate about formfeed disposition */
#define TELOPT_NAOVTS   14      /* negotiate about vertical tab stops */
#define TELOPT_NAOVTD   15      /* negotiate about vertical tab disposition */
#define TELOPT_NAOLFD   16      /* negotiate about output LF disposition */
#define TELOPT_XASCII   17      /* extended ascii character set */
#define TELOPT_LOGOUT   18      /* force logout */
#define TELOPT_BM       19      /* byte macro */
#define TELOPT_DET      20      /* data entry terminal */
#define TELOPT_SUPDUP   21      /* supdup protocol */
#define TELOPT_SUPDUPOUTPUT 22  /* supdup output */
#define TELOPT_SNDLOC   23      /* send location */
#define TELOPT_TTYPE    24      /* terminal type */
#define TELOPT_EOR      25      /* end or record */
#define TELOPT_TUID     26      /* TACACS user identification */
#define TELOPT_OUTMRK   27      /* output marking */
#define TELOPT_TTYLOC   28      /* terminal location number */
#define TELOPT_3270REGIME 29    /* 3270 regime */
#define TELOPT_X3PAD    30      /* X.3 PAD */
#define TELOPT_NAWS     31      /* window size */
#define TELOPT_TSPEED   32      /* terminal speed */
#define TELOPT_LFLOW    33      /* remote flow control */
#define TELOPT_LINEMODE 34      /* Linemode option */
#define TELOPT_XDISPLOC 35      /* X Display Location */
#define TELOPT_OLD_ENVIRON 36   /* Old - Environment variables */
#define TELOPT_AUTHENTICATION 37/* Authenticate */
#define TELOPT_ENCRYPT  38      /* Encryption option */
#define TELOPT_NEW_ENVIRON 39   /* New - Environment variables */
#define TELOPT_EXOPL    255     /* extended-options-list */


#define NTELOPTS        (1+TELOPT_NEW_ENVIRON)
static const char *telopts[NTELOPTS+1] = {
       "BINARY", "ECHO", "RCP", "SUPPRESS GO AHEAD", "NAME",
       "STATUS", "TIMING MARK", "RCTE", "NAOL", "NAOP",
       "NAOCRD", "NAOHTS", "NAOHTD", "NAOFFD", "NAOVTS",
       "NAOVTD", "NAOLFD", "EXTEND ASCII", "LOGOUT", "BYTE MACRO",
       "DATA ENTRY TERMINAL", "SUPDUP", "SUPDUP OUTPUT",
       "SEND LOCATION", "TERMINAL TYPE", "END OF RECORD",
       "TACACS UID", "OUTPUT MARKING", "TTYLOC",
       "3270 REGIME", "X.3 PAD", "NAWS", "TSPEED", "LFLOW",
       "LINEMODE", "XDISPLOC", "OLD-ENVIRON", "AUTHENTICATION",
       "ENCRYPT", "NEW-ENVIRON",
       0,
};
#define TELOPT_FIRST    TELOPT_BINARY
#define TELOPT_LAST     TELOPT_NEW_ENVIRON
#define TELOPT_OK(x)    ((unsigned int)(x) <= TELOPT_LAST)
#define TELOPT(x)       telopts[(x)-TELOPT_FIRST]

/* sub-option qualifiers */
#define TELQUAL_IS      0       /* option is... */
#define TELQUAL_SEND    1       /* send option */
#define TELQUAL_INFO    2       /* ENVIRON: informational version of IS */
#define TELQUAL_REPLY   2       /* AUTHENTICATION: client version of IS */
#define TELQUAL_NAME    3       /* AUTHENTICATION: client version of IS */

#define LFLOW_OFF               0       /* Disable remote flow control */
#define LFLOW_ON                1       /* Enable remote flow control */
#define LFLOW_RESTART_ANY       2       /* Restart output on any char */
#define LFLOW_RESTART_XON       3       /* Restart output only on XON */

/*
* LINEMODE suboptions
*/

#define LM_MODE         1
#define LM_FORWARDMASK  2
#define LM_SLC          3

#define MODE_EDIT       0x01
#define MODE_TRAPSIG    0x02
#define MODE_ACK        0x04
#define MODE_SOFT_TAB   0x08
#define MODE_LIT_ECHO   0x10

#define MODE_MASK       0x1f

#define SLC_SYNCH       1
#define SLC_BRK         2
#define SLC_IP          3
#define SLC_AO          4
#define SLC_AYT         5
#define SLC_EOR         6
#define SLC_ABORT       7
#define SLC_EOF         8
#define SLC_SUSP        9
#define SLC_EC          10
#define SLC_EL          11
#define SLC_EW          12
#define SLC_RP          13
#define SLC_LNEXT       14
#define SLC_XON         15
#define SLC_XOFF        16
#define SLC_FORW1       17
#define SLC_FORW2       18
#define SLC_MCL         19
#define SLC_MCR         20
#define SLC_MCWL        21
#define SLC_MCWR        22
#define SLC_MCBOL       23
#define SLC_MCEOL       24
#define SLC_INSRT       25
#define SLC_OVER        26
#define SLC_ECR         27
#define SLC_EWR         28
#define SLC_EBOL        29
#define SLC_EEOL        30

#define NSLC            30

/*
* For backwards compatibility, we define SLC_NAMES to be the
* list of names if SLC_NAMES is not defined.
*/
#define SLC_NAMELIST    "0", "SYNCH", "BRK", "IP", "AO", "AYT", "EOR",  \
                       "ABORT", "EOF", "SUSP", "EC", "EL", "EW", "RP", \
                       "LNEXT", "XON", "XOFF", "FORW1", "FORW2",       \
                       "MCL", "MCR", "MCWL", "MCWR", "MCBOL",          \
                       "MCEOL", "INSRT", "OVER", "ECR", "EWR",         \
                       "EBOL", "EEOL",                                 \
                       0,

#ifdef  SLC_NAMES
const char *slc_names[] = {
       SLC_NAMELIST
};
#else
extern char *slc_names[];
#define SLC_NAMES SLC_NAMELIST
#endif

#define SLC_NAME_OK(x)  ((unsigned int)(x) <= NSLC)
#define SLC_NAME(x)     slc_names[x]

#define SLC_NOSUPPORT   0
#define SLC_CANTCHANGE  1
#define SLC_VARIABLE    2
#define SLC_DEFAULT     3
#define SLC_LEVELBITS   0x03

#define SLC_FUNC        0
#define SLC_FLAGS       1
#define SLC_VALUE       2

#define SLC_ACK         0x80
#define SLC_FLUSHIN     0x40
#define SLC_FLUSHOUT    0x20

#define OLD_ENV_VAR     1
#define OLD_ENV_VALUE   0
#define NEW_ENV_VAR     0
#define NEW_ENV_VALUE   1
#define ENV_ESC         2
#define ENV_USERVAR     3

/*
* AUTHENTICATION suboptions
*/

/*
* Who is authenticating who ...
*/
#define AUTH_WHO_CLIENT         0       /* Client authenticating server */
#define AUTH_WHO_SERVER         1       /* Server authenticating client */
#define AUTH_WHO_MASK           1

#define AUTHTYPE_NULL           0
#define AUTHTYPE_KERBEROS_V4    1
#define AUTHTYPE_KERBEROS_V5    2
#define AUTHTYPE_SPX            3
#define AUTHTYPE_MINK           4
#define AUTHTYPE_CNT            5

#define AUTHTYPE_TEST           99

#ifdef  AUTH_NAMES
const char *authtype_names[] = {
       "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK", 0,
};
#else
extern char *authtype_names[];
#endif

#define AUTHTYPE_NAME_OK(x)     ((unsigned int)(x) < AUTHTYPE_CNT)
#define AUTHTYPE_NAME(x)        authtype_names[x]

/*
* ENCRYPTion suboptions
*/
#define ENCRYPT_IS              0       /* I pick encryption type ... */
#define ENCRYPT_SUPPORT         1       /* I support encryption types ... */
#define ENCRYPT_REPLY           2       /* Initial setup response */
#define ENCRYPT_START           3       /* Am starting to send encrypted */
#define ENCRYPT_END             4       /* Am ending encrypted */
#define ENCRYPT_REQSTART        5       /* Request you start encrypting */
#define ENCRYPT_REQEND          6       /* Request you send encrypting */
#define ENCRYPT_ENC_KEYID       7
#define ENCRYPT_DEC_KEYID       8
#define ENCRYPT_CNT             9

#define ENCTYPE_ANY             0
#define ENCTYPE_DES_CFB64       1
#define ENCTYPE_DES_OFB64       2
#define ENCTYPE_CNT             3

#ifdef  ENCRYPT_NAMES
const char *encrypt_names[] = {
       "IS", "SUPPORT", "REPLY", "START", "END",
       "REQUEST-START", "REQUEST-END", "ENC-KEYID", "DEC-KEYID",
       0,
};
const char *enctype_names[] = {
       "ANY", "DES_CFB64",  "DES_OFB64",  0,
};
#else
extern char *encrypt_names[];
extern char *enctype_names[];
#endif

#define ENCRYPT_NAME_OK(x)      ((unsigned int)(x) < ENCRYPT_CNT)
#define ENCRYPT_NAME(x)         encrypt_names[x]

#define ENCTYPE_NAME_OK(x)      ((unsigned int)(x) < ENCTYPE_CNT)
#define ENCTYPE_NAME(x)         enctype_names[x]

/* normal */
static const char *cmds[] = {
       "IS", "SEND", "INFO",
};

/* 37: Authentication */
static const char *authcmd[] = {
       "IS", "SEND", "REPLY", "NAME",
};
static const char *authtype[] = {
       "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
       "SRP", "RSA", "SSL", NULL, NULL,
       "LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
       "NTLM",
};

/* 38: Encryption */
static const char *enccmd[] = {
       "IS", "SUPPORT", "REPLY", "START", "END",
       "REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
};
static const char *enctype[] = {
       "NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
       NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
};

#define STR_OR_ID(x, tab) \
       (((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))

static char *
numstr(int x)
{
       static char buf[20];

       snprintf(buf, sizeof(buf), "%#x", x);
       return buf;
}

/* sp points to IAC byte */
static int
telnet_parse(netdissect_options *ndo, const u_char *sp, u_int length, int print)
{
       int i, x;
       u_int c;
       const u_char *osp, *p;
#define FETCH(c, sp, length) \
       do { \
               if (length < 1) \
                       goto pktend; \
               c = GET_U_1(sp); \
               sp++; \
               length--; \
       } while (0)

       osp = sp;

       FETCH(c, sp, length);
       if (c != IAC)
               goto pktend;
       FETCH(c, sp, length);
       if (c == IAC) {         /* <IAC><IAC>! */
               if (print)
                       ND_PRINT("IAC IAC");
               goto done;
       }

       i = c - TELCMD_FIRST;
       if (i < 0 || i > IAC - TELCMD_FIRST)
               goto pktend;

       switch (c) {
       case DONT:
       case DO:
       case WONT:
       case WILL:
       case SB:
               /* DONT/DO/WONT/WILL x */
               FETCH(x, sp, length);
               if (x >= 0 && x < NTELOPTS) {
                       if (print)
                               ND_PRINT("%s %s", telcmds[i], telopts[x]);
               } else {
                       if (print)
                               ND_PRINT("%s %#x", telcmds[i], x);
               }
               if (c != SB)
                       break;
               /* IAC SB .... IAC SE */
               p = sp;
               while (length > (u_int)(p + 1 - sp)) {
                       if (GET_U_1(p) == IAC && GET_U_1(p + 1) == SE)
                               break;
                       p++;
               }
               if (GET_U_1(p) != IAC)
                       goto pktend;

               switch (x) {
               case TELOPT_AUTHENTICATION:
                       if (p <= sp)
                               break;
                       FETCH(c, sp, length);
                       if (print)
                               ND_PRINT(" %s", STR_OR_ID(c, authcmd));
                       if (p <= sp)
                               break;
                       FETCH(c, sp, length);
                       if (print)
                               ND_PRINT(" %s", STR_OR_ID(c, authtype));
                       break;
               case TELOPT_ENCRYPT:
                       if (p <= sp)
                               break;
                       FETCH(c, sp, length);
                       if (print)
                               ND_PRINT(" %s", STR_OR_ID(c, enccmd));
                       if (p <= sp)
                               break;
                       FETCH(c, sp, length);
                       if (print)
                               ND_PRINT(" %s", STR_OR_ID(c, enctype));
                       break;
               default:
                       if (p <= sp)
                               break;
                       FETCH(c, sp, length);
                       if (print)
                               ND_PRINT(" %s", STR_OR_ID(c, cmds));
                       break;
               }
               while (p > sp) {
                       FETCH(x, sp, length);
                       if (print)
                               ND_PRINT(" %#x", x);
               }
               /* terminating IAC SE */
               if (print)
                       ND_PRINT(" SE");
               sp += 2;
               break;
       default:
               if (print)
                       ND_PRINT("%s", telcmds[i]);
               goto done;
       }

done:
       return (int)(sp - osp);

pktend:
       return -1;
#undef FETCH
}

void
telnet_print(netdissect_options *ndo, const u_char *sp, u_int length)
{
       int first = 1;
       const u_char *osp;
       int l;

       ndo->ndo_protocol = "telnet";
       osp = sp;

       while (length > 0 && GET_U_1(sp) == IAC) {
               /*
                * Parse the Telnet command without printing it,
                * to determine its length.
                */
               l = telnet_parse(ndo, sp, length, 0);
               if (l < 0)
                       break;

               /*
                * now print it
                */
               if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag) {
                       if (first)
                               ND_PRINT("\nTelnet:");
                       hex_print_with_offset(ndo, "\n", sp, l, (u_int)(sp - osp));
                       if (l > 8)
                               ND_PRINT("\n\t\t\t\t");
                       else
                               ND_PRINT("%*s\t", (8 - l) * 3, "");
               } else
                       ND_PRINT("%s", (first) ? " [telnet " : ", ");

               (void)telnet_parse(ndo, sp, length, 1);
               first = 0;

               sp += l;
               length -= l;
       }
       if (!first) {
               if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag)
                       ND_PRINT("\n");
               else
                       ND_PRINT("]");
       }
}

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