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Length: 20352 (0x4f80)
Types: TextFile
Names: »TELNET.C«
└─⟦23f778bf6⟧ Bits:30005378 BDS C v1.46 & Pascal/MT+ v5.5 (Callan format)
└─ ⟦this⟧ »TELNET.C«
└─⟦4ada80662⟧ Bits:30005446 Pascal/MT+ v5.5 & XREF & BDS C v1.46
└─ ⟦this⟧ »TELNET.C«
#define TITLE "BDS Telnet version 2.3 (July 1980)"
/*
Written by Leor Zolman and Leo Kenen
July 1980
This version has been modified to obtain all hardware-
dependent information from bdscio.h, which must contain
the correct hardware specifications for your console and
modem ports.
If you intend to use this program for high speed
(i.e, greater than 300 baud) data transfers, such as
maybe over RS232 lines between two machines directly,
then the speed of transfer will be limited by the
processors involved instead of the baud rate;
UNDER SUCH CIRCUMSTANCES, A TRANSFER WILL ONLY WORK IF
THESE TWO CONDITIONS ARE MET:
1) The transfer must always performd in BINARY
mode, never in TEXT mode, and
2) The receiving processor must be as fast or
FASTER than the transmitting processor. That
is, a 2 MHz machine may transmit to a 4 MHz
machine at, say, 9600 baud, BUT NOT VICE-
VERSA.
* Telnet assumes that your CP/M console *
* I/O device is much faster than your *
* modem. On a 2MHz 8080, the modem can *
* be receiving at up to 300 baud as long *
* as your console whips along (at the *
* very least) at about 1200. 4 MHz mach- *
* ines might be able to get away with *
* slower terminals, but not much slower. *
"Telnet" is a program which interacts with a modem to turn
your microcomputer into a very versatile terminal. Special
commands are entered to the program by typing the character
you designate as "SPECIAL", i.e, some character (such as the
null or ^A ) which you wouldn't be likely to need transmitted,
and then entering the appropriate command letter. Incoming
data may be buffered up in RAM memory and dumped to disk
whenever you desire (via the "o", "d", "c" and "k" commands),
data may be transmitted from disk to modem (via "t" and "a"),
or files can be formally transferred in an alternate
"checksum" mode which handles handshaking and buffering
automatically when interacting with the same program on
the other end of the line. During file transfers, you
may temporarily pause and later resume the transmission
(via the "p" and "r" commands.) There are also various
options you can control (see "n", "7", "h" and "l") to
adapt operation toward the type of file you wish to
transfer. The "q" command closes the output file (if open)
and quits to CP/M. The "s" command displays the status of
the program. "z" clears the console screen. Any other
command letter (such as, for example, "?") causes a list
of legal commands to be displayed.
Telnet considers "half-duplex" to be any situation in
which an echo is received FROM the modem for each character
sent TO the modem (whether it is the modem generating the
echo OR the remote system being connected to), and
"full-duplex" is when no echo comes back.
In order to transmit or receive files in the checksum
mode, each party must make sure that his modem is
operating in FULL-DUPLEX, i.e., that the modem is not
generating an automatic echo. Checksumming and handshaking
is not allowed under half-duplex operation, since the echoes
would mess up handshaking. When you run telnet, it will
ask you whether or not you are running half-duplex, and
perform accordingly. If you switch from half to full or
vice-versa while running the program, use the "h" option
to inform telnet of the fact. You must be in "half-duplex"
mode to perform checksumed transfers.
To perform checksummed file transfer, a connection must
first be established between the two parties. If both
parties are operating in full duplex, one originating and the
other answering, then telnet will both display what each
types to the console and send it to the modem. If a file
then needs to be transferred, then one user would give the
"t" command (to transmit) and the other would give the "o"
command (to open an output file.) If both users indicate
checksum mode (rather than only one specifing checksum mode
which will abort almost immediatly), then telnet will take
it from there and perform the transfer. If the sender
(transmitter) wants to suspend the transfer temporarily and
continue later, he can use the "p" command. When the receiver
sees that transmission has been suspended (when no data has
been sent for a long time), then HE gives the "p" command also,
and both users may type to each other. When ready to resume,
the "r" command must be given by the RECEIVER first, and
then the sender, to prevent data from being lost.
*/
#include "bdscio.h" /* System, h'ware constants */
#define SPECIAL 0x1e /* The character you type to
signal a Telnet command
(should be obscure...I use
a "control-shift-uparrow") */
/*
The following #defines need not be changed:
*/
#define ACK 0x06 /* Ascii ACK for handshaking */
#define NAK 0x15
#define EOT 0x04 /* End of transmission */
#define ETX 0x03 /* Abort Transmission */
/*
External variable declarations:
*/
char rflag; /* receiving file open flag */
char tflag; /* transmitting file open flag */
char chflag; /* checksumming enabled flag */
char cflag; /* text-collection enabled flag */
char pflag; /* pausing flag */
char spflag; /* stripping parity bit flag */
char lflag; /* list device enabled flag */
char nflag; /* recognizing nulls flag */
char fflag; /* true if changing CR-LF's into
just CR when transmitting */
char lastc; /* last char xmitted */
char dodflag; /* true if displaying outging
data */
char didflag; /* true if displaying incoming
data */
char hdflag; /* true if effectively working
in half-duplex */
char abortf; /* true when file I/O aborted */
char rbufÆBUFSIZÅ; /* file I/O buffer for incoming
data file */
char tbufÆSECSIZÅ; /* sector buffer for file being
transmitted */
char rnameÆ20Å; /* name of receiving file */
char tnameÆ20Å; /* name of transmitting file */
int rfd, tfd; /* file descriptors */
char *cptr; /* pointer to free space in buf */
unsigned free; /* number of bytes free in buf */
int bcount; /* counts bytes in current block
when checksumming */
int scount; /* Number of sectors
sent/received */
int checksum; /* the checksum value itself */
char timoutf; /* true if time-out happens
while waiting for modem data */
char *i; /* odd-job char pointer */
int dod_sav, did_sav; /* scratch variables */
unsigned bufspace; /* # of bytes available for text
collection buffer in ram */
char *buf; /* text collection pointer; will
point to the location just
after itself */
char toupper(); /* This makes for better code
than if we let it default
to "int" */
/*
Routine to return true if input is present on
the modem:
*/
miready()
æ
return (inp(MSTAT) & MIMASK) == (MAHI ? MIMASK : 0);
å
/*
Routine to return true if modem is ready to output
a byte:
*/
moready()
æ
return (inp(MSTAT) & MOMASK) == (MAHI ? MOMASK : 0);
å
main()
æ
char c, c2;
int n;
init();
loop: if (abortf) æ
if (rflag) rclose();
if (tflag) tabort();
abortf = 0;
å
if (tflag && xmit()) æ
printf("ØnTransmission complete.Øn");
close(tfd);
reset();
å
if (abortf) goto loop;
if (miready()) æ
c = c2 = getmod();
if (spflag) c &= 0x7f;
if (tflag && (c == ETX)) æ
printf("Reciever has aborted;Øn");
abortf = 1;
goto loop;
å
if (didflag && (c øø nflag) && (c != CPMEOF))
display(c);
if (cflag && !pflag) æ
if (c øø nflag)
if (!free) printf("**BUFFER FULL**Ø007Ø007");
else æ *cptr++ = c; free--; å
if (chflag) æ
checksum += c2;
bcount++;
if (bcount == SECSIZ) æ
bcount = 0;
outmod(checksum >> 8);
outmod(checksum);
checksum = 0;
c = getmod();
if (c == EOT) æ
rdump(0); rclose();
printf("Øn%s recieved OKØn",rname);
å
else if (c == ACK) æ
if (cptr > buf+1000) rdump(0);
if (!didflag) printf("Good sector <%d>Øn",++scount);
outmod(0xFD);
å
else æ
cptr -= SECSIZ;
free += SECSIZ;
printf("ØnChecksum error. Retrying <%d>Øn",scount+1);
outmod(0xFD);
timoutf = 0;
å
å
å
å
å
if (kbready()) æ
c = getch();
if (c != SPECIAL) æ
if (pflag øø (!tflag && !(rflag && chflag))) æ
outmod(c);
if (dodflag) display(c);
å
å
else special();
å
goto loop;
å
/*
Handle special Telnet command:
*/
special()
æ
char c;
int n;
printf("ØnSpecial: ");
if ( (c = getchar()) != 'Øn') printf(" ");
switch (toupper(c)) æ
case 'Øn': return;
case SPECIAL: outmod(SPECIAL);
printf("Special char sentØn");
break;
case '7': spflag = ask("Strip parity");
break;
case 'N': nflag = ask("Recognize incoming nulls");
break;
case 'F': fflag = ask("Transmit CR-LF pairs as CR only");
break;
case 'H': if (rflag øø tflag) æ printf(
"Must abort transfer firstØn");
break;
å
printf("ØnAre you either at half");
printf("-duplex or getting an ");
hdflag = ask ("echo");
reset();
break;
case 'L': lflag = ask("List incoming data");
break;
case 'Z': printf(CLEARS);
break;
case 'P': if (pflag) printf("Already pausing");
else if (!(tflag øø rflag))
printf("Not transmitting or receiving");
else æ
pflag = 1;
dod_sav = dodflag;
did_sav = didflag;
dodflag = !hdflag;
didflag = 1;
printf("Ok, pausing from %s", tflag ?
"transmission" : "collection");
å
goto lf;
case 'R': if (!pflag) printf("Not pausing");
else æ
pflag = 0;
dodflag = dod_sav;
didflag = did_sav;
printf("%s now enabled again.", tflag ?
"transmission" : "collection");
å
goto lf;
case 'K': printf("Text buffer !ZAPPED!");
free = bufspace;
cptr = buf;
goto lf;
case 'V': if (rflag) æ
putchar('Øn');
i = buf;
while (i < cptr) putchar(*i++);
printf("Øn%u bytes free",free);
å
else printf("No recieving file open");
goto lf;
case 'O': if (rflag) rclose();
if (tflag) tabort();
printf("ØnOutput filename? ");
gets(rname);
rflag = 1;
if (!askstuff()) æ
rflag = 0;
return;
å
printf("Creating %s...",rname);
rfd = fcreat(rname,rbuf);
if (rfd == ERROR) æ
printf("Cannot create %sØn",rname);
reset();
break;
å
putchar('Øn');
cptr = buf;
free = bufspace;
rflag = cflag = 1;
pflag = checksum = bcount = 0;
if (chflag) æ
printf("Trying to link...");
do æ
c = getmod();
if (abortf) æ
printf("aborting...Øn");
unlink(rname);
reset();
return;
å
timoutf = 0;
å while (c & 0x7f);
printf("linked.Øn");
outmod(0);
å
break;
case 'D': if (rflag) rdump(1);
else printf("No output file");
goto lf;
case 'C': if (rflag) rclose();
else printf("No output file");
goto lf;
case 'Q': if (tflag) tabort();
if (rflag) rclose();
exit();
case 'A': if (tflag øø rflag) æ
if (chflag) outmod(ETX);
abortf = 1;
break;
å
printf("No transfer to abort.Øn");
goto lf;
case 'T': if (tflag) tabort();
if (rflag) rclose();
printf("ØnFile to transmit? ");
gets(tname);
tflag = 1;
if (!askstuff()) æ
tflag = 0;
return;
å
tfd = open(tname,0);
if (tfd == ERROR) æ
printf("Cannot open %sØn",tname);
reset();
goto lf;
å
pflag = checksum = bcount = 0;
if (read(tfd,tbuf,1) <=0) æ
printf("Read error from %sØn",
tname);
abortf = 1;
return;
å
if (chflag) æ
printf("Trying to link...");
while (1) æ
outmod(0);
for (n=0; n<5000; n++)
if (miready()) æ
if( !(getmod() & 0x7f)) æ
printf("linked.Øn");
return;
å
å
else if (kbabort()) æ
printf("aborting.Øn");
return;
å
å
å
break;
case 'S': dostat();
goto lf;
default: prcoms();
lf: putchar('Øn');
å
å
/*
Print out legal Telnet commands:
*/
prcoms()
æ
printf("ØnBDS Telnet commands are:Øn");
printf("Double SPECIAL: send SPECIALØn");
printf("o: Open output file, start collectionØn");
printf("p: Pause (suspend collection or transmission)Øn");
printf("r: Resume after pausingØn");
printf("d: Dump (append) text buffer to output fileØn");
printf("c: Close output file (after dumping buffer)Øn");
printf("v: View contents of text bufferØn");
printf("k: Kill (erase) contents of text bufferØn");
printf("t: Transmit a file to modemØn");
printf("a: Abort transfer of fileØn");
printf("n: accept or ignore NullsØn");
printf("7: select policy regarding Parity bitsØn");
printf("f: select whether to transmit CR-LF as just CRØn");
printf("h: set Half/full duplex modeØn");
printf("l: control CP/M List deviceØn");
printf("z: clear console terminal screenØn");
printf("s: display Status of TelnetØn");
printf("q: dump & close output file (if open) and Quit to CP/M");
å
/*
Print opening message and initialize program:
*/
init()
æ
printf(TITLE);
timoutf = cflag = nflag = lflag = pflag = abortf = fflag = 0;
spflag = 1;
lastc = 0;
buf = &buf + 1;
bufspace = buf + 500 - topofmem(); /* compute space available */
bufspace = -bufspace; /* for text collection buf */
printf("ØnØnAnswer `y' if either your modem is set to half-duplex,Øn");
printf("or you expect an echo from the system on the");
printf(" other endØn");
printf("of the line; else answer `n':Øn");
hdflag = ask("Do you expect an echo");
reset();
printf("OK; you're on line...ØnØn");
å
/*
Get all the info pertinent to a file transfer; i.e,
whether or not the file is text (and needs parity
stripped, nulls ignored, echoing to console, etc.),
whether or not checksumming and handshaking are
required (they always go together), and make sure
the user is in full duplex mode.
*/
askstuff()
æ
printf("Øn%s ",rflag ? "recieving" : "transmitting");
if (ask("text (y) or binary data (n) ")) æ
nflag = 0;
spflag = didflag = 1;
dodflag = !hdflag;
printf("Stripping parity, ignoring nulls,Øn");
printf(" %sdisplaying %s data.Øn",
(rflag ? didflag : dodflag) ? "" : "not ",
rflag ? "incoming" : "outgoing");
å
else æ
spflag = didflag = dodflag = 0;
nflag = 1;
printf("%s all data verbatim, and notØn",
rflag ? "Recieving" : "Sending");
printf("displaying it on the console.Øn");
å
putchar('Øn');
printf("Handshaking & checksumming can only happenØn");
printf("if the other computer has this same programØn");
printf("running. Do you want handshaking & checksumming");
chflag = ask("");
if (chflag && hdflag) æ
printf("Can't do it unless you can eliminate");
printf(" the echo! Aborting.Øn");
return 0;
å
scount = 0;
return ask("OK...type y to begin, n to abort:");
å
/*
Routine to print out a string and return true
if the user responds positively
*/
int ask(s)
char *s;
æ
char c;
while (1)
æ
printf("%s ",s);
printf("(y/n)? ");
c = toupper(getchar());
if (c == 'Y')
æ
printf("esØn");
return 1;
å
else if (c == 'N')
æ
printf("oØn");
return 0;
å
else putchar('Øn');
å
å
/*
Print out state of Telnet program:
*/
dostat()
æ
putchar('Øn');
if (rflag) æ
printf("Output file = %sØn",rname);
printf("Text buffer has %u bytes free",
free);
printf("ØnText collection: ");
if (cflag) if (pflag) printf("on, but pausingØn");
else printf("onØn");
else printf("offØn");
å
else printf("No output fileØn");
if (tflag) æ
printf("Transmitting: %s ",
tname);
if (pflag) printf("(but pausing)");
putchar('Øn');
å
else printf("Not transmitting any fileØn");
printf("Incoming nulls are being %sØn",
nflag ?"collected" : "ignored");
printf("Parity bits are being %sØn",
spflag ?"stripped" : "preserved");
printf("Half-duplex mode: %s",
hdflag ? "on" : "off");
å
/*
Routine to dump contents of the memory text buffer
to the output file and clear the buffer for more
data:
(Note that the "else putchar('Ø0');" clause may not
be necessary on your system; this is here only to
make up for a strange "feature" of Lifeboat's
Northstar CBIOS where disk polling happens during
console output, potentially causing bytes to be
missed from the modem.)
*/
rdump(n)
æ
for (i=buf; i<cptr; i++) putc(*i,rbuf);
cptr = buf;
free = bufspace;
if (n) printf("ØnBuffer writtenØn");
else putchar('Ø0');
å
/*
Routine to dump and close the output file:
*/
rclose()
æ
rdump(1);
printf(" Closing %s ",rname);
if (!chflag) putc(CPMEOF,rbuf);
fflush(rbuf);
close(rfd);
reset();
putchar('Øn');
å
/*
Routine to reset telnet
*/
reset()
æ
timoutf = rflag = tflag = chflag = cflag = 0;
scount = 0;
spflag = 1;
dodflag = !hdflag;
didflag = 1;
å
/*
Get a byte from the modem:
*/
getmod()
æ
char c;
unsigned n;
if (timoutf) return;
for (n=20000; !miready() && n; n--)
if (kbabort()) return;
if (!n) æ
timoutf = 1;
return 1;
å
c = inp(MDATA);
if (MRESET) outp(MSTAT,MRESETVAL);
return c;
å
/*
Output a byte to the modem:
*/
outmod(c)
char c;
æ
while (!moready())
if (kbabort()) return;
outp(MDATA,c);
å
kbready()
æ
return bios(2);
å
/*
Get a character from the keyboard:
(Uses a direct BIOS instead of going through
the BDOS. By naming this the same as the library
version of "getchar", we insure that THIS version
is used by things like "gets" instead of the library
version.)
*/
getchar()
æ
char c;
c = getch();
if (c == 'Ør') c = 'Øn';
putchar(c);
return c;
å
getch()
æ
return bios(3);
å
/*
Return true if keyboard hit and SPECIAL
typed:
*/
kbabort()
æ
if (kbready() && getch() == SPECIAL) æ
abortf = 1;
return 1;
å
return 0;
å
/*
Write a character to the console.
*/
putchar(c)
char c;
æ
if (c == 'Øn') putch2('Ør');
putch2(c);
å
putch2(c)
char c;
æ
bios(4,c);
å
/*
Write character to console display, and also to
system list device if that is enabled:
*/
display(c)
char c;
æ
if (c==CPMEOF) return;
putch2(c);
if (lflag) bdos(5,c);
å
xmit()
æ
int incheck;
int n;
char c;
if (pflag øø !moready()) return 0;
c = tbufÆbcount++Å;
checksum += c;
if ((!(spflag && (c&0x7f)==CPMEOF && !chflag)) &&
(!(!chflag && c=='Øn' && lastc=='Ør' &&
!nflag && fflag))) outmod(c);
lastc = c;
if (dodflag) display(c);
if (bcount != SECSIZ) return 0;
bcount = 0;
if (!chflag) return !read1();
incheck = (getmod() << 8) + getmod();
if (incheck != checksum) æ
for (n=0; n<20000; n++); /* let line settle down */
printf("ØnError. Resending sector %d...Øn",scount+1);
outmod(NAK);
å
else if (read1()) æ
if (!dodflag) printf("Good sector <%d>Øn",++scount);
outmod(ACK);
å
else æ outmod(EOT); return 1; å
checksum = 0;
if (getmod() != 0xFD) æ
printf("ØnPhase error; aborting...");
abortf = 1;
å
return 0;
å
/*
Read a sector of the transmission file:
*/
read1()
æ
int i;
i = read(tfd, tbuf, 1);
if ( i == ERROR) æ
printf("ØnRead error from %s; Aborting.Øn",
tname);
tabort();
å
return i;
å
tabort()
æ
if (chflag) while (bcount++ != 133) outmod(ETX);
printf("ØnTransmission of %s aborted.Øn",tname);
close(tfd);
reset();
å
«eof»