* 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
* <jam@ltsp.org>
* Modified 2004/02/11 to add ability to pass the USER variable to remote host
* by Fernando Silveira <swrh@gmx.net>
- *
*/
+//config:config TELNET
+//config: bool "telnet (8.7 kb)"
+//config: default y
+//config: help
+//config: Telnet is an interface to the TELNET protocol, but is also commonly
+//config: used to test other simple protocols.
+//config:
+//config:config FEATURE_TELNET_TTYPE
+//config: bool "Pass TERM type to remote host"
+//config: default y
+//config: depends on TELNET
+//config: help
+//config: Setting this option will forward the TERM environment variable to the
+//config: remote host you are connecting to. This is useful to make sure that
+//config: things like ANSI colors and other control sequences behave.
+//config:
+//config:config FEATURE_TELNET_AUTOLOGIN
+//config: bool "Pass USER type to remote host"
+//config: default y
+//config: depends on TELNET
+//config: help
+//config: Setting this option will forward the USER environment variable to the
+//config: remote host you are connecting to. This is useful when you need to
+//config: log into a machine without telling the username (autologin). This
+//config: option enables '-a' and '-l USER' options.
+//config:
+//config:config FEATURE_TELNET_WIDTH
+//config: bool "Enable window size autodetection"
+//config: default y
+//config: depends on TELNET
+
+//applet:IF_TELNET(APPLET(telnet, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_TELNET) += telnet.o
+
+//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"
+#include "common_bufsiz.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;
#if ENABLE_FEATURE_TELNET_AUTOLOGIN
const char *autologin;
#endif
-#if ENABLE_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_TELNET_WIDTH
unsigned win_width, win_height;
#endif
/* same buffer used both for network and console read/write */
struct termios termios_def;
struct termios termios_raw;
} FIX_ALIASING;
-#define G (*(struct globals*)&bb_common_bufsiz1)
+#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { \
- struct G_sizecheck { \
- char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
- }; \
+ setup_common_bufsiz(); \
+ BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
} 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)
{
- write(netfd, G.iacbuf, G.iaclen);
+ full_write(netfd, G.iacbuf, G.iaclen);
G.iaclen = 0;
}
-#define write_str(fd, str) write(fd, str, sizeof(str) - 1)
-
static void doexit(int ev) NORETURN;
static void doexit(int ev)
{
if (bb_got_signal) /* came from line mode... go raw */
rawmode();
- write_str(1, "\r\nConsole escape. Commands are:\r\n\n"
+ full_write1_str("\r\nConsole escape. Commands are:\r\n\n"
" l go to line mode\r\n"
" c go to character mode\r\n"
" z suspend telnet\r\n"
doexit(EXIT_SUCCESS);
}
- write_str(1, "continuing...\r\n");
+ full_write1_str("continuing...\r\n");
if (bb_got_signal)
cookmode();
ret:
bb_got_signal = 0;
-
}
static void handle_net_output(int len)
{
- /* here we could do smart tricks how to handle 0xFF:s in output
- * stream like writing twice every sequence of FF:s (thus doing
- * many write()s. But I think interactive telnet application does
- * not need to be 100% 8-bit clean, so changing every 0xff:s to
- * 0x7f:s
- *
- * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
- * I don't agree.
- * first - I cannot use programs like sz/rz
- * second - the 0x0D is sent as one character and if the next
- * char is 0x0A then it's eaten by a server side.
- * third - why do you have to make 'many write()s'?
- * I don't understand.
- * So I implemented it. It's really useful for me. I hope that
- * other people will find it interesting too.
- */
-
- int i, j;
- byte *p = (byte*)G.buf;
- byte outbuf[4*DATABUFSIZE];
-
- for (i = len, j = 0; i > 0; i--, p++) {
- if (*p == 0x1d) {
+ byte outbuf[2 * DATABUFSIZE];
+ byte *dst = outbuf;
+ byte *src = (byte*)G.buf;
+ byte *end = src + len;
+
+ while (src < end) {
+ byte c = *src++;
+ if (c == 0x1d) {
con_escape();
return;
}
- outbuf[j++] = *p;
- if (*p == 0xff)
- outbuf[j++] = 0xff;
- else if (*p == 0x0d)
- outbuf[j++] = 0x00;
+ *dst = c;
+ if (c == IAC)
+ *++dst = c; /* IAC -> IAC IAC */
+ else
+ if (c == '\r' || c == '\n') {
+ /* Enter key sends '\r' in raw mode and '\n' in cooked one.
+ *
+ * See RFC 1123 3.3.1 Telnet End-of-Line Convention.
+ * Using CR LF instead of other allowed possibilities
+ * like CR NUL - easier to talk to HTTP/SMTP servers.
+ */
+ *dst = '\r'; /* Enter -> CR LF */
+ *++dst = '\n';
+ }
+ dst++;
}
- if (j > 0)
- write(netfd, outbuf, j);
+ if (dst - outbuf != 0)
+ full_write(netfd, outbuf, dst - outbuf);
}
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)
G.iacbuf[G.iaclen++] = c;
}
-static void put_iac2(byte wwdd, byte c)
+static void put_iac2_merged(unsigned wwdd_and_c)
{
if (G.iaclen + 3 > IACBUFSIZE)
iac_flush();
put_iac(IAC);
- put_iac(wwdd);
- put_iac(c);
+ put_iac(wwdd_and_c >> 8);
+ put_iac(wwdd_and_c & 0xff);
}
+#define put_iac2(wwdd,c) put_iac2_merged(((wwdd)<<8) + (c))
#if ENABLE_FEATURE_TELNET_TTYPE
static void put_iac_subopt(byte c, char *str)
}
#endif
-#if ENABLE_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_TELNET_WIDTH
static void put_iac_naws(byte c, int x, int y)
{
if (G.iaclen + 9 > IACBUFSIZE)
put_iac(SB);
put_iac(c);
- put_iac((x >> 8) & 0xff);
- put_iac(x & 0xff);
- put_iac((y >> 8) & 0xff);
- put_iac(y & 0xff);
+ /* "... & 0xff" implicitly done below */
+ put_iac(x >> 8);
+ put_iac(x);
+ put_iac(y >> 8);
+ put_iac(y);
put_iac(IAC);
put_iac(SE);
}
#endif
-static char const escapecharis[] ALIGN1 = "\r\nEscape character is ";
-
static void setConMode(void)
{
if (G.telflags & UF_ECHO) {
if (G.charmode == CHM_TRY) {
G.charmode = CHM_ON;
- printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
+ printf("\r\nEntering %s mode"
+ "\r\nEscape character is '^%c'.\r\n", "character", ']');
rawmode();
}
} else {
if (G.charmode != CHM_OFF) {
G.charmode = CHM_OFF;
- printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
+ printf("\r\nEntering %s mode"
+ "\r\nEscape character is '^%c'.\r\n", "line", 'C');
cookmode();
}
}
}
#endif
-#if ENABLE_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_TELNET_WIDTH
static void to_naws(void)
{
/* Tell server we will do NAWS */
case TELOPT_NEW_ENVIRON:
to_new_environ(); break;
#endif
-#if ENABLE_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_TELNET_WIDTH
case TELOPT_NAWS:
to_naws();
put_iac_naws(c, G.win_width, G.win_height);
}
/* subnegotiation -- ignore all (except TTYPE,NAWS) */
-static int subneg(byte c)
+static void subneg(byte c)
{
switch (G.telstate) {
case TS_SUB1:
#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();
-#if ENABLE_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_TELNET_WIDTH
get_terminal_width_height(0, &G.win_width, &G.win_height);
#endif
}
#if ENABLE_FEATURE_TELNET_AUTOLOGIN
- if (1 & getopt32(argv, "al:", &G.autologin))
+ if (1 == getopt32(argv, "al:", &G.autologin)) {
+ /* Only -a without -l USER picks $USER from envvar */
G.autologin = getenv("USER");
+ }
argv += optind;
#else
argv++;
xmove_fd(create_and_connect_stream_or_die(host, port), netfd);
- setsockopt(netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+ setsockopt_keepalive(netfd);
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) {
- 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);
+ 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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