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larsbrinkhofflarsbrinkhoff
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TELNET server and client.
1 parent 6363ea1 commit 97715be

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4 files changed

+252
-1
lines changed

4 files changed

+252
-1
lines changed

‎.gitignore

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,4 +5,6 @@ src/libncp.a
55
src/ping
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src/finger
77
src/finser
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src/telnet
9+
src/telser
810
test/*.log

‎src/Makefile

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@ CFLAGS=-g -Wall
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33
NCP=-L. -lncp
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5-
all: ncp ping finger finser
5+
all: ncp ping finger finser telnet telser
66

77
ncp: ncp.o imp.o
88

@@ -18,3 +18,9 @@ finger: finger.o libncp.a
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finser: finser.o libncp.a
2020
$(CC) -o $@ $< $(NCP)
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telnet: telnet.o libncp.a
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$(CC) -o $@ $< $(NCP)
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telser: telser.o libncp.a
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$(CC) -o $@ $< $(NCP)

‎src/telnet.c

Lines changed: 201 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,201 @@
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#include <stdio.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include "ncp.h"
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#define IAC 0377
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#define DONT 0376
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#define DO 0375
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#define WONT 0374
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#define WILL 0373
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#define SB 0372
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#define GA 0371
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#define EL 0370
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#define EC 0367
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#define AYT 0366
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#define AO 0365
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#define IP 0364
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#define BRK 0363
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#define MARK 0362
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#define NOP 0361
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#define SE 0360
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static void option (unsigned char c)
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{
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switch (c) {
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case 000:
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fprintf (stderr, "[Binary Transmission]");
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break;
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case 001:
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fprintf (stderr, "[Echo]");
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break;
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case 002:
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fprintf (stderr, "[Reconnection]");
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break;
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case 003:
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fprintf (stderr, "[Suppress Go Ahead]");
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break;
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case 004:
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fprintf (stderr, "[Approx Message Size Negotiation]");
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break;
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case 005:
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fprintf (stderr, "[Status]");
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break;
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case 006:
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fprintf (stderr, "[Timing Mark]");
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break;
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case 007:
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fprintf (stderr, "[Remote Controlled Trans and Echo]");
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break;
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case 021:
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fprintf (stderr, "[Extended Ascii]");
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break;
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case 025:
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fprintf (stderr, "[Supdup]");
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break;
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case 026:
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fprintf (stderr, "[Supdup Output]");
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break;
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default:
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fprintf (stderr, "[Unknown Option]");
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break;
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}
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}
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static int special (unsigned char c, const unsigned char *data)
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{
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switch (c) {
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case IAC:
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write (1, &c, 1);
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return 0;
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case DONT:
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fprintf (stderr, "[DONT]");
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option (*data);
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return 1;
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case DO:
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fprintf (stderr, "[DO]");
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option (*data);
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return 1;
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case WONT:
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fprintf (stderr, "[WONT]");
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option (*data);
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return 1;
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case WILL:
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fprintf (stderr, "[WILL]");
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option (*data);
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return 1;
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case SB:
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fprintf (stderr, "[SB]");
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return 0;
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case GA:
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fprintf (stderr, "[GA]");
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return 0;
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case EL:
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fprintf (stderr, "[EL]");
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return 0;
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case EC:
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fprintf (stderr, "[EC]");
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write (1, "\b \b", 3);
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return 0;
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case AYT:
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fprintf (stderr, "[AYT]");
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return 0;
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case AO:
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fprintf (stderr, "[AO]");
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return 0;
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case IP:
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fprintf (stderr, "[IP]");
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return 0;
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case BRK:
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fprintf (stderr, "[BRK]");
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return 0;
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case MARK:
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fprintf (stderr, "[MARK]");
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return 0;
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case NOP:
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fprintf (stderr, "[NOP]");
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return 0;
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case SE:
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fprintf (stderr, "[SE]");
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return 0;
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default:
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fprintf (stderr, "[Unknown Option]");
125+
return 0;
126+
}
127+
}
128+
129+
static void process (const unsigned char *data, int size)
130+
{
131+
int i;
132+
133+
for (i = 0; i < size; i++) {
134+
switch (data[i]) {
135+
case NUL:
136+
break;
137+
case IAC:
138+
i += special (data[i+1], &data[i+2]);
139+
break;
140+
default:
141+
write (1, &data[i], 1);
142+
break;
143+
}
144+
}
145+
146+
int main (int argc, char **argv)
147+
{
148+
char options[] = {
149+
IAC, DO, 001,
150+
IAC, DO, 003,
151+
IAC, WILL, 003
152+
};
153+
unsigned char reply[1000];
154+
int host, connection, size;
155+
156+
if (argc != 2) {
157+
fprintf (stderr, "Usage: %s host\n", argv[0]);
158+
exit (1);
159+
}
160+
161+
host = atoi (argv[1]);
162+
163+
if (ncp_init (NULL) == -1) {
164+
fprintf (stderr, "NCP initializtion error: %s.\n", strerror (errno));
165+
if (errno == ECONNREFUSED)
166+
fprintf (stderr, "Is the NCP server started?\n");
167+
exit (1);
168+
}
169+
170+
printf ("TELNET to host %03o.\n", host);
171+
172+
switch (ncp_open (host, 23, &connection)) {
173+
case 0:
174+
break;
175+
case -1:
176+
default:
177+
fprintf (stderr, "NCP open error.\n");
178+
exit (1);
179+
case -2:
180+
fprintf (stderr, "Open refused.\n");
181+
exit (1);
182+
}
183+
184+
if (ncp_write (connection, options, strlen (options)) == -1) {
185+
fprintf (stderr, "NCP write error.\n");
186+
exit (1);
187+
}
188+
189+
size = sizeof reply;
190+
if (ncp_read (connection, reply, &size) == -1) {
191+
fprintf (stderr, "NCP read error.\n");
192+
exit (1);
193+
}
194+
195+
process (reply, size);
196+
197+
if (ncp_close (connection) == -1) {
198+
fprintf (stderr, "NCP close error.\n");
199+
exit (1);
200+
}
201+
}

‎src/telser.c

Lines changed: 42 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,42 @@
1+
#include <stdio.h>
2+
#include <errno.h>
3+
#include <stdlib.h>
4+
#include <unistd.h>
5+
#include <string.h>
6+
#include "ncp.h"
7+
8+
int main (int argc, char **argv)
9+
{
10+
char *command;
11+
char reply[1000];
12+
int host, connection, size;
13+
14+
if (argc != 1) {
15+
fprintf (stderr, "Usage: %s\n", argv[0]);
16+
exit (1);
17+
}
18+
19+
if (ncp_init (NULL) == -1) {
20+
fprintf (stderr, "NCP initializtion error: %s.\n", strerror (errno));
21+
if (errno == ECONNREFUSED)
22+
fprintf (stderr, "Is the NCP server started?\n");
23+
exit (1);
24+
}
25+
26+
if (ncp_listen (23, &host, &connection) == -1) {
27+
fprintf (stderr, "NCP listen error.\n");
28+
exit (1);
29+
}
30+
31+
command = "Welcome to Unix.\r\n";
32+
if (ncp_write (connection, command, strlen (command)) == -1) {
33+
fprintf (stderr, "NCP write error.\n");
34+
exit (1);
35+
}
36+
37+
if (ncp_close (connection) == -1) {
38+
fprintf (stderr, "NCP close error.\n");
39+
exit (1);
40+
}
41+
42+
}

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