* Created: Thu Apr 7 13:29:41 1994 too
* Last modified: Fri Jun 9 14:34:24 2000 too
*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
* HISTORY
* Revision 3.1 1994/04/17 11:31:54 too
*
*/
+//usage:#if ENABLE_FEATURE_TELNET_AUTOLOGIN
+//usage:#define telnet_trivial_usage
+//usage: "[-a] [-l USER] HOST [PORT]"
+//usage:#define telnet_full_usage "\n\n"
+//usage: "Connect to telnet server\n"
+//usage: "\n -a Automatic login with $USER variable"
+//usage: "\n -l USER Automatic login as USER"
+//usage:
+//usage:#else
+//usage:#define telnet_trivial_usage
+//usage: "HOST [PORT]"
+//usage:#define telnet_full_usage "\n\n"
+//usage: "Connect to telnet server"
+//usage:#endif
+
#include <arpa/telnet.h>
#include <netinet/in.h>
#include "libbb.h"
+#ifdef __BIONIC__
+/* should be in arpa/telnet.h */
+# 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 SE 240 /* end sub negotiation */
+# define TELOPT_ECHO 1 /* echo */
+# define TELOPT_SGA 3 /* suppress go ahead */
+# define TELOPT_TTYPE 24 /* terminal type */
+# define TELOPT_NAWS 31 /* window size */
+#endif
+
#ifdef DOTRACE
-#define TRACE(x, y) do { if (x) printf y; } while (0)
+# define TRACE(x, y) do { if (x) printf y; } while (0)
#else
-#define TRACE(x, y)
+# define TRACE(x, y)
#endif
enum {
UF_ECHO = 0x01,
UF_SGA = 0x02,
- TS_0 = 1,
+ TS_NORMAL = 0,
+ TS_COPY = 1,
TS_IAC = 2,
TS_OPT = 3,
TS_SUB1 = 4,
TS_SUB2 = 5,
+ TS_CR = 6,
};
typedef unsigned char byte;
}; \
} while (0)
-/* Function prototypes */
+
static void rawmode(void);
static void cookmode(void);
static void do_linemode(void);
static void will_charmode(void);
static void telopt(byte c);
-static int subneg(byte c);
+static void subneg(byte c);
static void iac_flush(void)
{
cookmode();
ret:
bb_got_signal = 0;
-
}
static void handle_net_output(int len)
* So I implemented it. It's really useful for me. I hope that
* other people will find it interesting too.
*/
-
- int i, j;
+ byte outbuf[2 * DATABUFSIZE];
byte *p = (byte*)G.buf;
- byte outbuf[4*DATABUFSIZE];
+ int j = 0;
- for (i = len, j = 0; i > 0; i--, p++) {
- if (*p == 0x1d) {
+ for (; len > 0; len--, p++) {
+ byte c = *p;
+ if (c == 0x1d) {
con_escape();
return;
}
- outbuf[j++] = *p;
- if (*p == 0xff)
- outbuf[j++] = 0xff;
- else if (*p == 0x0d)
- outbuf[j++] = 0x00;
+ outbuf[j++] = c;
+ if (c == IAC)
+ outbuf[j++] = c; /* IAC -> IAC IAC */
+ else if (c == '\r')
+ outbuf[j++] = '\0'; /* CR -> CR NUL */
}
if (j > 0)
- write(netfd, outbuf, j);
+ full_write(netfd, outbuf, j);
}
static void handle_net_input(int len)
for (i = 0; i < len; i++) {
byte c = G.buf[i];
- if (G.telstate == 0) { /* most of the time state == 0 */
+ if (G.telstate == TS_NORMAL) { /* most typical state */
if (c == IAC) {
cstart = i;
G.telstate = TS_IAC;
}
+ else if (c == '\r') {
+ cstart = i + 1;
+ G.telstate = TS_CR;
+ }
+ /* No IACs were seen so far, no need to copy
+ * bytes within G.buf: */
continue;
}
+
switch (G.telstate) {
- case TS_0:
+ case TS_CR:
+ /* Prev char was CR. If cur one is NUL, ignore it.
+ * See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
+ */
+ G.telstate = TS_COPY;
+ if (c == '\0')
+ break;
+ /* else: fall through - need to handle CR IAC ... properly */
+
+ case TS_COPY: /* Prev char was ordinary */
+ /* Similar to NORMAL, but in TS_COPY we need to copy bytes */
if (c == IAC)
G.telstate = TS_IAC;
else
G.buf[cstart++] = c;
+ if (c == '\r')
+ G.telstate = TS_CR;
break;
- case TS_IAC:
- if (c == IAC) { /* IAC IAC -> 0xFF */
+ case TS_IAC: /* Prev char was IAC */
+ if (c == IAC) { /* IAC IAC -> one IAC */
G.buf[cstart++] = c;
- G.telstate = TS_0;
+ G.telstate = TS_COPY;
break;
}
/* else */
case DONT:
case WILL:
case WONT:
- G.telwish = c;
+ G.telwish = c;
G.telstate = TS_OPT;
break;
+ /* DATA MARK must be added later */
default:
- G.telstate = TS_0; /* DATA MARK must be added later */
+ G.telstate = TS_COPY;
}
break;
- case TS_OPT: /* WILL, WONT, DO, DONT */
+
+ case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
telopt(c);
- G.telstate = TS_0;
+ G.telstate = TS_COPY;
break;
+
case TS_SUB1: /* Subnegotiation */
case TS_SUB2: /* Subnegotiation */
- if (subneg(c))
- G.telstate = TS_0;
+ subneg(c); /* can change G.telstate */
break;
}
}
- if (G.telstate) {
+
+ if (G.telstate != TS_NORMAL) {
+ /* We had some IACs, or CR */
if (G.iaclen)
iac_flush();
- if (G.telstate == TS_0)
- G.telstate = 0;
+ if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
+ G.telstate = TS_NORMAL;
len = cstart;
}
if (len)
- write(STDOUT_FILENO, G.buf, len);
+ full_write(STDOUT_FILENO, G.buf, len);
}
static void put_iac(int c)
static void put_iac_subopt_autologin(void)
{
int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2)
- const char *user = "USER";
+ const char *p = "USER";
if (G.iaclen + len > IACBUFSIZE)
iac_flush();
put_iac(TELQUAL_IS);
put_iac(NEW_ENV_VAR);
- while (*user)
- put_iac(*user++);
+ while (*p)
+ put_iac(*p++);
put_iac(NEW_ENV_VALUE);
- while (*G.autologin)
- put_iac(*G.autologin++);
+ p = G.autologin;
+ while (*p)
+ put_iac(*p++);
put_iac(IAC);
put_iac(SE);
put_iac2(DONT, TELOPT_ECHO);
setConMode();
- write_str(1, "\r\n"); /* sudden modec */
+ full_write1_str("\r\n"); /* sudden modec */
}
static void to_sga(void)
static void to_ttype(void)
{
/* Tell server we will (or won't) do TTYPE */
-
if (G.ttype)
put_iac2(WILL, TELOPT_TTYPE);
else
static void to_new_environ(void)
{
/* Tell server we will (or will not) do AUTOLOGIN */
-
if (G.autologin)
put_iac2(WILL, TELOPT_NEW_ENVIRON);
else
}
/* subnegotiation -- ignore all (except TTYPE,NAWS) */
-static int subneg(byte c)
+static void subneg(byte c)
{
switch (G.telstate) {
case TS_SUB1:
G.telstate = TS_SUB2;
#if ENABLE_FEATURE_TELNET_TTYPE
else
- if (c == TELOPT_TTYPE)
+ if (c == TELOPT_TTYPE && G.ttype)
put_iac_subopt(TELOPT_TTYPE, G.ttype);
#endif
#if ENABLE_FEATURE_TELNET_AUTOLOGIN
else
- if (c == TELOPT_NEW_ENVIRON)
+ if (c == TELOPT_NEW_ENVIRON && G.autologin)
put_iac_subopt_autologin();
#endif
break;
case TS_SUB2:
- if (c == SE)
- return TRUE;
+ if (c == SE) {
+ G.telstate = TS_COPY;
+ return;
+ }
G.telstate = TS_SUB1;
- /* break; */
+ break;
}
- return FALSE;
}
static void rawmode(void)
tcsetattr(0, TCSADRAIN, &G.termios_def);
}
-/* poll gives smaller (-70 bytes) code */
-#define USE_POLL 1
-
int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int telnet_main(int argc UNUSED_PARAM, char **argv)
{
char *host;
int port;
int len;
-#ifdef USE_POLL
struct pollfd ufds[2];
-#else
- fd_set readfds;
- int maxfd;
-#endif
INIT_G();
signal(SIGINT, record_signo);
-#ifdef USE_POLL
- ufds[0].fd = 0; ufds[1].fd = netfd;
- ufds[0].events = ufds[1].events = POLLIN;
-#else
- FD_ZERO(&readfds);
- FD_SET(STDIN_FILENO, &readfds);
- FD_SET(netfd, &readfds);
- maxfd = netfd + 1;
-#endif
+ ufds[0].fd = STDIN_FILENO;
+ ufds[0].events = POLLIN;
+ ufds[1].fd = netfd;
+ ufds[1].events = POLLIN;
while (1) {
-#ifndef USE_POLL
- fd_set rfds = readfds;
-
- switch (select(maxfd, &rfds, NULL, NULL, NULL))
-#else
- switch (poll(ufds, 2, -1))
-#endif
- {
- case 0:
- /* timeout */
- case -1:
+ if (poll(ufds, 2, -1) < 0) {
/* error, ignore and/or log something, bay go to loop */
if (bb_got_signal)
con_escape();
else
sleep(1);
- break;
- default:
+ continue;
+ }
-#ifdef USE_POLL
- if (ufds[0].revents)
-#else
- if (FD_ISSET(STDIN_FILENO, &rfds))
-#endif
- {
- len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
- if (len <= 0)
- doexit(EXIT_SUCCESS);
- TRACE(0, ("Read con: %d\n", len));
- handle_net_output(len);
- }
+// FIXME: reads can block. Need full bidirectional buffering.
-#ifdef USE_POLL
- if (ufds[1].revents)
-#else
- if (FD_ISSET(netfd, &rfds))
-#endif
- {
- len = safe_read(netfd, G.buf, DATABUFSIZE);
- if (len <= 0) {
- write_str(1, "Connection closed by foreign host\r\n");
- doexit(EXIT_FAILURE);
- }
- TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
- handle_net_input(len);
+ if (ufds[0].revents) {
+ len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
+ if (len <= 0)
+ doexit(EXIT_SUCCESS);
+ TRACE(0, ("Read con: %d\n", len));
+ handle_net_output(len);
+ }
+
+ if (ufds[1].revents) {
+ len = safe_read(netfd, G.buf, DATABUFSIZE);
+ if (len <= 0) {
+ full_write1_str("Connection closed by foreign host\r\n");
+ doexit(EXIT_FAILURE);
}
+ TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
+ handle_net_input(len);
}
} /* while (1) */
}
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