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SOURCE.ARC
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TELNET.C
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C/C++ Source or Header
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1990-02-04
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10KB
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484 lines
#include <stdio.h>
#include "global.h"
#include "mbuf.h"
#include "timer.h"
#include "icmp.h"
#include "netuser.h"
#include "tcp.h"
#include "telnet.h"
#include "session.h"
#define CTLZ 26
extern char nospace[];
extern char badhost[];
int refuse_echo = 0;
int unix_line_mode = 0; /* if true turn <cr> to <nl> when in line mode */
#ifdef DEBUG
char *t_options[] = {
"Transmit Binary",
"Echo",
"",
"Suppress Go Ahead",
"",
"Status",
"Timing Mark"
};
#endif
/* Execute user telnet command */
int
dotelnet(argc,argv)
int argc;
char *argv[];
{
void t_state(),rcv_char(),tn_tx();
int32 resolve();
int send_tel();
int unix_send_tel();
struct session *s;
struct telnet *tn;
struct tcb *tcb;
struct socket lsocket,fsocket;
char tos = 0;
lsocket.address = ip_addr;
lsocket.port = lport++;
if((fsocket.address = resolve(argv[1])) == 0){
printf(badhost,argv[1]);
return 1;
}
if(argc < 3)
fsocket.port = TELNET_PORT;
else {
if((fsocket.port = atoi(argv[2])) == 0)
fsocket.port = TELNET_PORT;
tos = get_tos(argv[3]);
}
/* Allocate a session descriptor */
if((s = newsession()) == NULLSESSION){
printf("Too many sessions\n");
return 1;
}
if((s->name = malloc((unsigned)strlen(argv[1])+1)) != NULLCHAR)
strcpy(s->name,argv[1]);
s->type = TELNET;
if ((refuse_echo == 0) && (unix_line_mode != 0)) {
s->parse = unix_send_tel;
} else {
s->parse = send_tel;
}
current = s;
/* Create and initialize a Telnet protocol descriptor */
if((tn = (struct telnet *)calloc(1,sizeof(struct telnet))) == NULLTN){
printf(nospace);
s->type = FREE;
return 1;
}
tn->session = s; /* Upward pointer */
tn->state = TS_DATA;
s->cb.telnet = tn; /* Downward pointer */
tcb = open_tcp(&lsocket,&fsocket,TCP_ACTIVE,0,
rcv_char,tn_tx,t_state,tos,(char *)tn);
tn->tcb = tcb; /* Downward pointer */
go();
return 0;
}
/* Process typed characters */
int
unix_send_tel(buf,n)
char *buf;
int16 n;
{
int i;
for (i=0; (i<n) && (buf[i] != '\r'); i++)
;
if (buf[i] == '\r') {
buf[i] = '\n';
n = i+1;
}
send_tel(buf,n);
}
int
send_tel(buf,n)
char *buf;
int16 n;
{
struct mbuf *bp,*qdata();
if(current == NULLSESSION || current->cb.telnet == NULLTN
|| current->cb.telnet->tcb == NULLTCB)
return;
/* If we're doing our own echoing and recording is enabled, record it */
if(!current->cb.telnet->remote[TN_ECHO] && current->record != NULLFILE)
fwrite(buf,1,n,current->record);
bp = qdata(buf,n);
send_tcp(current->cb.telnet->tcb,bp);
}
/* Process incoming TELNET characters */
int
tel_input(tn,bp)
register struct telnet *tn;
struct mbuf *bp;
{
char c;
void doopt(),dontopt(),willopt(),wontopt(),answer();
FILE *record;
#if (!defined(MSC) && !defined(__TURBOC__))
char *memchr();
#endif
/* Optimization for very common special case -- no special chars */
if(tn->state == TS_DATA){
while(bp != NULLBUF && memchr(bp->data,IAC,bp->cnt) == NULL){
if((record = tn->session->record) != NULLFILE)
fwrite(bp->data,1,bp->cnt,record);
while(bp->cnt-- != 0)
putchar(*bp->data++);
bp = free_mbuf(bp);
}
}
while(pullup(&bp,&c,1) == 1){
switch(tn->state){
case TS_DATA:
if(uchar(c) == IAC){
tn->state = TS_IAC;
} else {
if(!tn->remote[TN_TRANSMIT_BINARY])
c &= 0x7f;
putchar(c);
if((record = tn->session->record) != NULLFILE)
putc(c,record);
}
break;
case TS_IAC:
switch(uchar(c)){
case WILL:
tn->state = TS_WILL;
break;
case WONT:
tn->state = TS_WONT;
break;
case DO:
tn->state = TS_DO;
break;
case DONT:
tn->state = TS_DONT;
break;
case IAC:
putchar(c);
tn->state = TS_DATA;
break;
default:
tn->state = TS_DATA;
break;
}
break;
case TS_WILL:
willopt(tn,c);
tn->state = TS_DATA;
break;
case TS_WONT:
wontopt(tn,c);
tn->state = TS_DATA;
break;
case TS_DO:
doopt(tn,c);
tn->state = TS_DATA;
break;
case TS_DONT:
dontopt(tn,c);
tn->state = TS_DATA;
break;
}
}
}
/* Telnet receiver upcall routine */
void
rcv_char(tcb,cnt)
register struct tcb *tcb;
int16 cnt;
{
struct mbuf *bp;
struct telnet *tn;
FILE *record;
extern int flowctrl,ttydriv();
if((tn = (struct telnet *)tcb->user) == NULLTN){
/* Unknown connection; ignore it */
return;
}
/* Hold output if we're not the current session, and while typing */
if(mode != CONV_MODE || current == NULLSESSION
|| current->type != TELNET || current->cb.telnet != tn
|| (flowctrl && ttydriv(-1,NULL)))
return;
if(recv_tcp(tcb,&bp,cnt) > 0)
tel_input(tn,bp);
fflush(stdout);
if((record = tn->session->record) != NULLFILE)
fflush(record);
}
/* Handle transmit upcalls. Used only for file uploading */
void
tn_tx(tcb,cnt)
struct tcb *tcb;
int16 cnt;
{
struct telnet *tn;
struct session *s;
struct mbuf *bp;
int size;
if((tn = (struct telnet *)tcb->user) == NULLTN
|| (s = tn->session) == NULLSESSION
|| s->upload == NULLFILE)
return;
while((bp = alloc_mbuf(cnt)) == NULLBUF && (cnt /= 2) != 0)
;
if(bp == NULLBUF)
return;
if((size = fread(bp->data,1,cnt,s->upload)) > 0){
bp->cnt = (int16)size;
send_tcp(tcb,bp);
} else {
free_p(bp);
}
if(size != cnt){
/* Error or end-of-file */
fclose(s->upload);
s->upload = NULLFILE;
free(s->ufile);
s->ufile = NULLCHAR;
}
}
/* State change upcall routine */
void
t_state(tcb,old,new)
register struct tcb *tcb;
char old,new;
{
struct telnet *tn;
char notify = 0;
extern char *tcpstates[];
extern char *reasons[];
extern char *unreach[];
extern char *exceed[];
/* Can't add a check for unknown connection here, it would loop
* on a close upcall! We're just careful later on.
*/
tn = (struct telnet *)tcb->user;
if(current != NULLSESSION && current->type == TELNET && current->cb.telnet == tn)
notify = 1;
switch(new){
case CLOSE_WAIT:
if(notify)
printf("%s\n",tcpstates[new]);
close_tcp(tcb);
break;
case CLOSED: /* court adjourned */
if(notify){
printf("%s (%s",tcpstates[new],reasons[tcb->reason]);
if(tcb->reason == NETWORK){
switch(tcb->type){
case DEST_UNREACH:
printf(": %s unreachable",unreach[tcb->code]);
break;
case TIME_EXCEED:
printf(": %s time exceeded",exceed[tcb->code]);
break;
}
}
printf(")\n");
cmdmode();
}
del_tcp(tcb);
if(tn != NULLTN)
free_telnet(tn);
break;
default:
if(notify)
printf("%s\n",tcpstates[new]);
break;
}
fflush(stdout);
}
/* Delete telnet structure */
static
free_telnet(tn)
struct telnet *tn;
{
if(tn->session != NULLSESSION)
freesession(tn->session);
if(tn != NULLTN)
free((char *)tn);
}
/* The guts of the actual Telnet protocol: negotiating options */
static
void
willopt(tn,opt)
struct telnet *tn;
char opt;
{
int ack;
void answer();
#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
raw(); /* Put tty into raw mode */
}
tn->remote[uchar(opt)] = 1;
ack = DO;
break;
default:
ack = DONT; /* We don't know what he's offering; refuse */
}
answer(tn,ack,opt);
}
static
void
wontopt(tn,opt)
struct telnet *tn;
char opt;
{
void answer();
#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)
cooked();