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telnet.c
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C/C++ Source or Header
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1994-09-16
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563 lines
/* Internet Telnet client
* Copyright 1991 Phil Karn, KA9Q
*/
/****************************************************************************
* $Id: telnet.c 1.2 93/07/16 11:51:27 ROOT_DOS Exp $
* 08 May 93 1.2 GT Fix warnings. *
*
* ATARI Version by David Nash - dnash@chaos.demon.co.uk
*
* 10.03.93 - Lookup port number from service nmemonic added
*
* __stdargs dotelnet, tel_output
****************************************************************************/
#include <stdio.h>
#ifdef __TURBOC__
#include <io.h>
#include <fcntl.h>
#endif
#ifdef ATARI
#include <ctype.h>
#endif
#include "global.h"
#include "mbuf.h"
#include "socket.h"
#include "telnet.h"
#include "session.h"
#include "proc.h"
#include "tty.h"
#include "commands.h"
#include "netuser.h"
static int filemode __ARGS((FILE *fp,int mode));
int service_code(char *);
#define CTLZ 26
int Refuse_echo = 0;
int Tn_cr_mode = 0; /* if true turn <cr> to <cr-nul> */
/*
Define port numbers for common services
*/
static struct svc {
char *name;
int service_code;
} services[] = {
"tcpmux", 1, /* TCP Multiplexor */
"rje", 5, /* Remote Job Entry */
"echo", 7, /* Echo */
"discard", 9, /* Discard */
"users", 11, /* Active Users */
"systat", 11, /* Active Users */
"daytime", 13, /* Daytime */
"netstat", 15, /* Who is up or NETSTAT */
"qotd", 17, /* Quote of the Day */
"quote", 17, /* Quote of the Day */
"chargen", 19, /* Character Generator */
"ftp-data", 20, /* File Transter Protocol (Data) */
"ftp", 21, /* File Transfer Protocol */
"telnet", 23, /* Terminal Connection */
"smtp", 25, /* Simple Mail Transfer Protocol */
"time", 37, /* Time */
"rlp", 39,
"name", 42, /* Host Name Server */
"nameserver", 42, /* Host Name Server */
"whois", 43, /* Who Is */
"nicname", 43, /* Who Is */
"domain", 53, /* Domain Name Server */
"bootps", 67, /* Bootstrap Protocol Server */
"bootpc", 68, /* Bootstrap Protocol Client */
"tftp", 69, /* Trivial File Transfer */
"finger", 79, /* Finger */
"chat", 87, /* TTYlink */
"link", 87, /* TTYlink */
"ttylink", 87, /* TTYlink */
"dcp", 93, /* Device Control Protocol */
"supdup", 95, /* SUPDUP Protocol */
"hostname", 101, /* NIC Host Name Server */
"iso-tsap", 102, /* ISO-TSAP */
"x400", 103, /* X.400 Mail Service */
"x400-snd", 104, /* X.400 Mail Sending */
"sunrpc", 111, /* Sun Microsystems RPC */
"auth", 113, /* Authentication Service */
"uucp-path", 117, /* UUCP Path Service */
"nntp", 119, /* USENET News Transfer Protocol */
"ntp", 123, /* Network Time Protocol */
"pwdgen", 129, /* Password Generator Protocol */
"netbios-ssn", 139, /* NETBIOS Session Service */
"snmp", 161, /* SNMP net monitor */
"snmp-trap", 162, /* SNMP traps */
"biff", 512, /* UNIX comsat */
"who", 513, /* UNIX rwho daemon */
"syslog", 514, /* system log */
"timed", 525, /* Time daemon */
(char *)0, -1
};
#ifdef DEBUG
char *T_options[] = {
"Transmit Binary",
"Echo",
"",
"Suppress Go Ahead",
"",
"Status",
"Timing Mark"
};
#endif
/* Execute user telnet command */
int __stdargs dotelnet(argc,argv,p)
int argc;
char *argv[];
void *p;
{
struct session *sp;
struct sockaddr_in fsocket;
/* Allocate a session descriptor */
if((sp = newsession(argv[1],TELNET)) == NULLSESSION){
tprintf("Too many sessions\n");
return 1;
}
fsocket.sin_family = AF_INET;
if(argc < 3)
fsocket.sin_port = IPPORT_TELNET;
else
fsocket.sin_port = service_code(argv[2]); /* port # lookup - DFN */
if (fsocket.sin_port < 0) {
tprintf("Unknown service: %s \n", argv[2]);
return -1;
}
tprintf("Resolving %s... ",sp->name);
if((fsocket.sin_addr.s_addr = resolve(sp->name)) == 0){
tprintf(Badhost,sp->name);
keywait(NULLCHAR,1);
freesession(sp);
return 1;
}
if((sp->s = socket(AF_INET,SOCK_STREAM,0)) == -1){
tprintf("Can't create socket\n");
keywait(NULLCHAR,1);
freesession(sp);
return 1;
}
return tel_connect(sp,(char *)&fsocket,SOCKSIZE);
}
/* Generic interactive connect routine, used by Telnet, AX.25, NET/ROM */
int
tel_connect(sp,fsocket,len)
struct session *sp;
char *fsocket;
int len;
{
unsigned int index;
struct telnet tn;
index = (unsigned int) (sp - Sessions);
memset((char *)&tn,0,sizeof(tn));
tn.eolmode = Tn_cr_mode;
tn.session = sp; /* Upward pointer */
sp->cb.telnet = &tn; /* Downward pointer */
sockmode(sp->s,SOCK_ASCII); /* Default to ascii mode */
tprintf("Trying %s...\n",psocket((struct sockaddr *)fsocket));
if(connect(sp->s,fsocket,len) == -1){
tprintf("%s session %u failed: %s errno %d\n",
Sestypes[sp->type], index, sockerr(sp->s),errno);
keywait(NULLCHAR,1);
freesession(sp);
return 1;
}
tprintf("%s session ",Sestypes[sp->type]);
tprintf("%u connected to %s\n",index,sp->name);
tnrecv(&tn);
return 0;
}
/* Telnet input routine, common to both telnet and ttylink */
void
tnrecv(tn)
struct telnet *tn;
{
int c,s,index;
struct session *sp;
char *cp;
sp = tn->session;
s = sp->s;
index = (int) (sp - Sessions);
/* Fork off the transmit process */
sp->proc1 = newproc("tel_out",1024,tel_output,0,tn,NULL,0);
/* Process input on the connection */
while((c = recvchar(s)) != -1){
if(c != IAC){
/* Ordinary character */
if(!tn->remote[TN_TRANSMIT_BINARY])
c &= 0x7f;
tputc((char)c);
continue;
}
/* IAC received, get command sequence */
c = recvchar(s);
switch(c){
case WILL:
c = recvchar(s);
willopt(tn,c);
break;
case WONT:
c = recvchar(s);
wontopt(tn,c);
break;
case DO:
c = recvchar(s);
doopt(tn,c);
break;
case DONT:
c = recvchar(s);
dontopt(tn,c);
break;
case IAC: /* Escaped IAC */
tputc((char)IAC);
break;
}
}
quit: /* A close was received from the remote host.
* Notify the user, kill the output task and wait for a response
* from the user before freeing the session.
*/
sockmode(sp->output,SOCK_ASCII); /* Restore newline translation */
cp = sockerr(s);
tprintf("%s session %u", Sestypes[sp->type],index);
tprintf(" closed: %s\n", cp != NULLCHAR ? cp : "EOF");
killproc(sp->proc1);
sp->proc1 = NULLPROC;
close_s(sp->s);
sp->s = -1;
keywait(NULLCHAR,1);
freesession(sp);
}
/* User telnet output task, started by user telnet command */
void __stdargs tel_output(unused,tn1,p)
int unused;
void *tn1;
void *p;
{
struct session *sp;
int c;
struct telnet *tn;
tn = (struct telnet *)tn1;
sp = tn->session;
/* Send whatever's typed on the terminal */
while((c = recvchar(sp->input)) != EOF){
usputc(sp->s,(char)c);
if(!tn->remote[TN_ECHO] && sp->record != NULLFILE)
putc(c,sp->record);
/* By default, output is transparent in remote echo mode.
* If eolmode is set, turn a cr into cr-null.
* This can only happen when in remote echo (raw) mode, since
* the tty driver normally maps \r to \n in cooked mode.
*/
if(c == '\r' && tn->eolmode)
usputc(sp->s,'\0');
if(tn->remote[TN_ECHO])
usflush(sp->s);
}
/* Make sure our parent doesn't try to kill us after we exit */
sp->proc1 = NULLPROC;
}
int
doecho(argc,argv,p)
int argc;
char *argv[];
void *p;
{
if(argc < 2){
if(Refuse_echo)
tprintf("Refuse\n");
else
tprintf("Accept\n");
} else {
if(argv[1][0] == 'r')
Refuse_echo = 1;
else if(argv[1][0] == 'a')
Refuse_echo = 0;
else
return -1;
}
return 0;
}
/* set for unix end of line for remote echo mode telnet */
int
doeol(argc,argv,p)
int argc;
char *argv[];
void *p;
{
if(argc < 2){
if(Tn_cr_mode)
tprintf("null\n");
else
tprintf("standard\n");
} else {
if(argv[1][0] == 'n')
Tn_cr_mode = 1;
else if(argv[1][0] == 's')
Tn_cr_mode = 0;
else {
tprintf("Usage: %s [standard|null]\n",argv[0]);
return -1;
}
}
return 0;
}
/* The guts of the actual Telnet protocol: negotiating options */
void
willopt(tn,opt)
struct telnet *tn;
int opt;
{
int ack;
#ifdef DEBUG
printf("recv: will ");
if(uchar(opt) <= NOPTIONS)
printf("%s\n",T_options[opt]);
else
printf("%u\n",opt);
#endif
switch(uchar(opt)){
case TN_TRANSMIT_BINARY:
case TN_ECHO:
case TN_SUPPRESS_GA:
if(tn->remote[uchar(opt)] == 1)
return; /* Already set, ignore to prevent loop */
if(uchar(opt) == TN_ECHO){
if(Refuse_echo){
/* User doesn't want to accept */
ack = DONT;
break;
} else {
/* Put tty into raw mode */
tn->session->ttystate.edit = 0;
tn->session->ttystate.echo = 0;
sockmode(tn->session->s,SOCK_BINARY);
sockmode(tn->session->input,SOCK_BINARY);
sockmode(tn->session->output,SOCK_BINARY);
if(tn->session->record != NULLFILE)
filemode(tn->session->record,SOCK_BINARY);
}
}
tn->remote[uchar(opt)] = 1;
ack = DO;
break;
default:
ack = DONT; /* We don't know what he's offering; refuse */
}
answer(tn,ack,opt);
}
void
wontopt(tn,opt)
struct telnet *tn;
int opt;
{
#ifdef DEBUG
printf("recv: wont ");
if(uchar(opt) <= NOPTIONS)
printf("%s\n",T_options[uchar(opt)]);
else
printf("%u\n",uchar(opt));
#endif
if(uchar(opt) <= NOPTIONS){
if(tn->remote[uchar(opt)] == 0)
return; /* Already clear, ignore to prevent loop */
tn->remote[uchar(opt)] = 0;
if(uchar(opt) == TN_ECHO){
/* Put tty into cooked mode */
tn->session->ttystate.edit = 1;
tn->session->ttystate.echo = 1;
sockmode(tn->session->s,SOCK_ASCII);
sockmode(tn->session->input,SOCK_ASCII);
sockmode(tn->session->output,SOCK_ASCII);
if(tn->session->record != NULLFILE)
filemode(tn->session->record,SOCK_ASCII);
}
}
answer(tn,DONT,opt); /* Must always accept */
}
void
doopt(tn,opt)
struct telnet *tn;
int opt;
{
int ack;
#ifdef DEBUG
printf("recv: do ");
if(uchar(opt) <= NOPTIONS)
printf("%s\n",T_options[uchar(opt)]);
else
printf("%u\n",uchar(opt));
#endif
switch(uchar(opt)){
case TN_SUPPRESS_GA:
if(tn->local[uchar(opt)] == 1)
return; /* Already set, ignore to prevent loop */
tn->local[uchar(opt)] = 1;
ack = WILL;
break;
default:
ack = WONT; /* Don't know what it is */
}
answer(tn,ack,opt);
}
void
dontopt(tn,opt)
struct telnet *tn;
int opt;
{
#ifdef DEBUG
printf("recv: dont ");
if(uchar(opt) <= NOPTIONS)
printf("%s\n",T_options[uchar(opt)]);
else
printf("%u\n",uchar(opt));
#endif
if(uchar(opt) <= NOPTIONS){
if(tn->local[uchar(opt)] == 0){
/* Already clear, ignore to prevent loop */
return;
}
tn->local[uchar(opt)] = 0;
}
answer(tn,WONT,opt);
}
void
answer(tn,r1,r2)
struct telnet *tn;
int r1,r2;
{
char s[3];
#ifdef DEBUG
switch(r1){
case WILL:
printf("sent: will ");
break;
case WONT:
printf("sent: wont ");
break;
case DO:
printf("sent: do ");
break;
case DONT:
printf("sent: dont ");
break;
}
if(r2 <= NOPTIONS)
printf("%s\n",T_options[r2]);
else
printf("%u\n",r2);
#endif
s[0] = IAC;
s[1] = r1;
s[2] = r2;
send(tn->session->s,s,3,0);
}
#ifdef __TURBOC__
/* Set end-of-line translation mode on file */
static int
filemode(fp,mode)
FILE *fp;
int mode;
{
int omode;
if(fp == NULLFILE)
return -1;
if(fp->flags & _F_BIN)
omode = SOCK_BINARY;
else
omode = SOCK_ASCII;
switch(mode){
case SOCK_BINARY:
fp->flags = _F_BIN;
setmode(fileno(fp),O_BINARY);
break;
case SOCK_ASCII:
fp->flags &= ~_F_BIN;
setmode(fileno(fp),O_TEXT);
break;
}
return omode;
}
#else
static int
filemode(fp,mode)
FILE *fp;
int mode;
{
return 0;
}
#endif
/*
service_code - return port number for a service mnemonic
*/
int service_code(char *str)
{
int i;
char sp[20];
char *cp, *ip ;
struct svc *svc = services;
cp = sp;
ip = str;
if (!(i = strlen(str)) || i > 19 )
return -1;
if (*str >= '0' && *str <= '9') /* convert numeric str to integer */
return atoi(str); /* return port number */
while (*ip != '\0') { /* convert text to lower case */
*cp++ = tolower(*ip);
ip++;
}
*cp = '\0';
while (svc->name) { /* scan the service code table */
if (!strcmp(svc->name, sp))
return svc->service_code;
svc++;
}
return -1;
}