X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/68a49acbf3f96fbbbc385620655dcb577e62c328..7555d6a50b05d96de39b5e95cf11a8f05f0c4fd9:/telnet.c

diff --git a/telnet.c b/telnet.c
index 18c7d0e4..36c0f723 100644
--- a/telnet.c
+++ b/telnet.c
@@ -72,6 +72,19 @@
 #define	TELOPT_AUTHENTICATION 37       /* Authenticate */
 #define	TELOPT_ENCRYPT	38	       /* Encryption option */
 #define TELOPT_NEW_ENVIRON 39	       /* New - Environment variables */
+#define TELOPT_TN3270E	40	       /* TN3270 enhancements */
+#define TELOPT_XAUTH	41
+#define TELOPT_CHARSET	42	       /* Character set */
+#define TELOPT_RSP	43	       /* Remote serial port */
+#define TELOPT_COM_PORT_OPTION 44      /* Com port control */
+#define TELOPT_SLE	45	       /* Suppress local echo */
+#define TELOPT_STARTTLS	46	       /* Start TLS */
+#define TELOPT_KERMIT	47	       /* Automatic Kermit file transfer */
+#define TELOPT_SEND_URL	48
+#define TELOPT_FORWARD_X 49
+#define TELOPT_PRAGMA_LOGON	138
+#define TELOPT_SSPI_LOGON	139
+#define TELOPT_PRAGMA_HEARTBEAT	140
 #define	TELOPT_EXOPL	255	       /* extended-options-list */
 
 #define	TELQUAL_IS	0	       /* option is... */
@@ -86,7 +99,9 @@
 #define LF 10
 #define NUL 0
 
-#define iswritable(x) ( (x) != IAC && (x) != CR )
+#define iswritable(x) \
+	( (x) != IAC && \
+	      (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
 
 static char *telopt(int opt)
 {
@@ -130,6 +145,19 @@ static char *telopt(int opt)
     i(AUTHENTICATION);
     i(ENCRYPT);
     i(NEW_ENVIRON);
+    i(TN3270E);
+    i(XAUTH);
+    i(CHARSET);
+    i(RSP);
+    i(COM_PORT_OPTION);
+    i(SLE);
+    i(STARTTLS);
+    i(KERMIT);
+    i(SEND_URL);
+    i(FORWARD_X);
+    i(PRAGMA_LOGON);
+    i(SSPI_LOGON);
+    i(PRAGMA_HEARTBEAT);
     i(EXOPL);
 #undef i
     return "<unknown>";
@@ -157,6 +185,8 @@ enum {
     OPTINDEX_ECHO,
     OPTINDEX_WE_SGA,
     OPTINDEX_THEY_SGA,
+    OPTINDEX_WE_BIN,
+    OPTINDEX_THEY_BIN,
     NUM_OPTS
 };
 
@@ -178,10 +208,14 @@ static const struct Opt o_we_sga =
     { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
 static const struct Opt o_they_sga =
     { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
+static const struct Opt o_we_bin =
+    { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
+static const struct Opt o_they_bin =
+    { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
 
 static const struct Opt *const opts[] = {
     &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
-    &o_we_sga, &o_they_sga, NULL
+    &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
 };
 
 typedef struct telnet_tag {
@@ -201,7 +235,7 @@ typedef struct telnet_tag {
     int bufsize;
     int in_synch;
     int sb_opt, sb_len;
-    char *sb_buf;
+    unsigned char *sb_buf;
     int sb_size;
 
     enum {
@@ -209,6 +243,9 @@ typedef struct telnet_tag {
 	    SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
     } state;
 
+    Config cfg;
+
+    Pinger pinger;
 } *Telnet;
 
 #define TELNET_MAX_BACKLOG 4096
@@ -225,12 +262,18 @@ static void c_write1(Telnet telnet, int c)
 
 static void log_option(Telnet telnet, char *sender, int cmd, int option)
 {
-    char buf[50];
-    sprintf(buf, "%s:\t%s %s", sender,
-	    (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
-	     cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
-	    telopt(option));
+    char *buf;
+    /*
+     * The strange-looking "<?""?>" below is there to avoid a
+     * trigraph - a double question mark followed by > maps to a
+     * closing brace character!
+     */
+    buf = dupprintf("%s:\t%s %s", sender,
+		    (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
+		     cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
+		    telopt(option));
     logevent(telnet->frontend, buf);
+    sfree(buf);
 }
 
 static void send_opt(Telnet telnet, int cmd, int option)
@@ -240,7 +283,7 @@ static void send_opt(Telnet telnet, int cmd, int option)
     b[0] = IAC;
     b[1] = cmd;
     b[2] = option;
-    telnet->bufsize = sk_write(telnet->s, b, 3);
+    telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
     log_option(telnet, "client", cmd, option);
 }
 
@@ -367,41 +410,43 @@ static void process_subneg(Telnet telnet)
     switch (telnet->sb_opt) {
       case TELOPT_TSPEED:
 	if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
-	    char logbuf[sizeof(cfg.termspeed) + 80];
+	    char *logbuf;
 	    b[0] = IAC;
 	    b[1] = SB;
 	    b[2] = TELOPT_TSPEED;
 	    b[3] = TELQUAL_IS;
-	    strcpy(b + 4, cfg.termspeed);
-	    n = 4 + strlen(cfg.termspeed);
+	    strcpy((char *)(b + 4), telnet->cfg.termspeed);
+	    n = 4 + strlen(telnet->cfg.termspeed);
 	    b[n] = IAC;
 	    b[n + 1] = SE;
-	    telnet->bufsize = sk_write(telnet->s, b, n + 2);
+	    telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
 	    logevent(telnet->frontend, "server:\tSB TSPEED SEND");
-	    sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
+	    logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);
 	    logevent(telnet->frontend, logbuf);
+	    sfree(logbuf);
 	} else
 	    logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
 	break;
       case TELOPT_TTYPE:
 	if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
-	    char logbuf[sizeof(cfg.termtype) + 80];
+	    char *logbuf;
 	    b[0] = IAC;
 	    b[1] = SB;
 	    b[2] = TELOPT_TTYPE;
 	    b[3] = TELQUAL_IS;
-	    for (n = 0; cfg.termtype[n]; n++)
-		b[n + 4] = (cfg.termtype[n] >= 'a'
-			    && cfg.termtype[n] <=
-			    'z' ? cfg.termtype[n] + 'A' -
-			    'a' : cfg.termtype[n]);
+	    for (n = 0; telnet->cfg.termtype[n]; n++)
+		b[n + 4] = (telnet->cfg.termtype[n] >= 'a'
+			    && telnet->cfg.termtype[n] <=
+			    'z' ? telnet->cfg.termtype[n] + 'A' -
+			    'a' : telnet->cfg.termtype[n]);
 	    b[n + 4] = IAC;
 	    b[n + 5] = SE;
-	    telnet->bufsize = sk_write(telnet->s, b, n + 6);
+	    telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
 	    b[n + 4] = 0;
 	    logevent(telnet->frontend, "server:\tSB TTYPE SEND");
-	    sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
+	    logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
 	    logevent(telnet->frontend, logbuf);
+	    sfree(logbuf);
 	} else
 	    logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
 	break;
@@ -410,12 +455,13 @@ static void process_subneg(Telnet telnet)
 	p = telnet->sb_buf;
 	q = p + telnet->sb_len;
 	if (p < q && *p == TELQUAL_SEND) {
-	    char logbuf[50];
+	    char *logbuf;
 	    p++;
-	    sprintf(logbuf, "server:\tSB %s SEND", telopt(telnet->sb_opt));
+	    logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
 	    logevent(telnet->frontend, logbuf);
+	    sfree(logbuf);
 	    if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
-		if (cfg.rfc_environ) {
+		if (telnet->cfg.rfc_environ) {
 		    value = RFC_VALUE;
 		    var = RFC_VAR;
 		} else {
@@ -448,7 +494,7 @@ static void process_subneg(Telnet telnet)
 	    b[2] = telnet->sb_opt;
 	    b[3] = TELQUAL_IS;
 	    n = 4;
-	    e = cfg.environmt;
+	    e = telnet->cfg.environmt;
 	    while (*e) {
 		b[n++] = var;
 		while (*e && *e != '\t')
@@ -460,23 +506,29 @@ static void process_subneg(Telnet telnet)
 		    b[n++] = *e++;
 		e++;
 	    }
-	    if (*cfg.username) {
+	    if (*telnet->cfg.username) {
 		b[n++] = var;
 		b[n++] = 'U';
 		b[n++] = 'S';
 		b[n++] = 'E';
 		b[n++] = 'R';
 		b[n++] = value;
-		e = cfg.username;
+		e = telnet->cfg.username;
 		while (*e)
 		    b[n++] = *e++;
 	    }
 	    b[n++] = IAC;
 	    b[n++] = SE;
-	    telnet->bufsize = sk_write(telnet->s, b, n);
-	    sprintf(logbuf, "client:\tSB %s IS %s", telopt(telnet->sb_opt),
-		    n == 6 ? "<nothing>" : "<stuff>");
+	    telnet->bufsize = sk_write(telnet->s, (char *)b, n);
+	    logbuf = dupprintf("client:\tSB %s IS %s%s%s%s",
+			       telopt(telnet->sb_opt),
+			       *telnet->cfg.username ? "USER=" : "",
+			       telnet->cfg.username,
+			       *telnet->cfg.username ? " " : "",
+			       n == 6 ? "<nothing>" :
+			       (*telnet->cfg.environmt ? "<stuff>" : ""));
 	    logevent(telnet->frontend, logbuf);
+	    sfree(logbuf);
 	}
 	break;
     }
@@ -511,7 +563,7 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
 		else if (c == DM)
 		    telnet->in_synch = 0;
 #endif
-		if (c == CR)
+		if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
 		    telnet->state = SEENCR;
 		else
 		    telnet->state = TOP_LEVEL;
@@ -566,18 +618,11 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
 	    else {
 	      subneg_addchar:
 		if (telnet->sb_len >= telnet->sb_size) {
-		    char *newbuf;
 		    telnet->sb_size += SB_DELTA;
-		    newbuf = (telnet->sb_buf ?
-			      srealloc(telnet->sb_buf, telnet->sb_size) :
-			      smalloc(telnet->sb_size));
-		    if (newbuf)
-			telnet->sb_buf = newbuf;
-		    else
-			telnet->sb_size -= SB_DELTA;
+		    telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
+					     unsigned char);
 		}
-		if (telnet->sb_len < telnet->sb_size)
-		    telnet->sb_buf[telnet->sb_len++] = c;
+		telnet->sb_buf[telnet->sb_len++] = c;
 		telnet->state = SUBNEGOT;	/* in case we came here by goto */
 	    }
 	    break;
@@ -593,7 +638,23 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
     }
 }
 
-static int telnet_closing(Plug plug, char *error_msg, int error_code,
+static void telnet_log(Plug plug, int type, SockAddr addr, int port,
+		       const char *error_msg, int error_code)
+{
+    Telnet telnet = (Telnet) plug;
+    char addrbuf[256], *msg;
+
+    sk_getaddr(addr, addrbuf, lenof(addrbuf));
+
+    if (type == 0)
+	msg = dupprintf("Connecting to %s port %d", addrbuf, port);
+    else
+	msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
+
+    logevent(telnet->frontend, msg);
+}
+
+static int telnet_closing(Plug plug, const char *error_msg, int error_code,
 			  int calling_back)
 {
     Telnet telnet = (Telnet) plug;
@@ -601,12 +662,13 @@ static int telnet_closing(Plug plug, char *error_msg, int error_code,
     if (telnet->s) {
         sk_close(telnet->s);
         telnet->s = NULL;
+	notify_remote_exit(telnet->frontend);
     }
     if (error_msg) {
-	/* A socket error has occurred. */
 	logevent(telnet->frontend, error_msg);
-	connection_fatal("%s", error_msg);
-    }				       /* Otherwise, the remote side closed the connection normally. */
+	connection_fatal(telnet->frontend, "%s", error_msg);
+    }
+    /* Otherwise, the remote side closed the connection normally. */
     return 0;
 }
 
@@ -633,20 +695,24 @@ static void telnet_sent(Plug plug, int bufsize)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static char *telnet_init(void *frontend_handle, void **backend_handle,
-			 char *host, int port, char **realhost, int nodelay)
+static const char *telnet_init(void *frontend_handle, void **backend_handle,
+			       Config *cfg,
+			       char *host, int port, char **realhost,
+			       int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
+	telnet_log,
 	telnet_closing,
 	telnet_receive,
 	telnet_sent
     };
     SockAddr addr;
-    char *err;
+    const char *err;
     Telnet telnet;
 
-    telnet = smalloc(sizeof(*telnet));
+    telnet = snew(struct telnet_tag);
     telnet->fn = &fn_table;
+    telnet->cfg = *cfg;		       /* STRUCTURE COPY */
     telnet->s = NULL;
     telnet->echoing = TRUE;
     telnet->editing = TRUE;
@@ -654,22 +720,30 @@ static char *telnet_init(void *frontend_handle, void **backend_handle,
     telnet->sb_buf = NULL;
     telnet->sb_size = 0;
     telnet->frontend = frontend_handle;
-    telnet->term_width = cfg.width;
-    telnet->term_height = cfg.height;
+    telnet->term_width = telnet->cfg.width;
+    telnet->term_height = telnet->cfg.height;
     telnet->state = TOP_LEVEL;
+    telnet->ldisc = NULL;
+    telnet->pinger = NULL;
     *backend_handle = telnet;
 
     /*
      * Try to find host.
      */
     {
-	char buf[200];
-	sprintf(buf, "Looking up host \"%.170s\"", host);
+	char *buf;
+	buf = dupprintf("Looking up host \"%s\"%s", host,
+			(cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
+			 (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
+			  "")));
 	logevent(telnet->frontend, buf);
+	sfree(buf);
     }
-    addr = sk_namelookup(host, realhost);
-    if ((err = sk_addr_error(addr)))
+    addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);
+    if ((err = sk_addr_error(addr)) != NULL) {
+	sk_addr_free(addr);
 	return err;
+    }
 
     if (port < 0)
 	port = 23;		       /* default telnet port */
@@ -677,23 +751,17 @@ static char *telnet_init(void *frontend_handle, void **backend_handle,
     /*
      * Open socket.
      */
-    {
-	char buf[200], addrbuf[100];
-	sk_getaddr(addr, addrbuf, 100);
-	sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
-	logevent(telnet->frontend, buf);
-    }
     telnet->s = new_connection(addr, *realhost, port, 0, 1,
-			       nodelay, (Plug) telnet);
-    if ((err = sk_socket_error(telnet->s)))
+			       nodelay, keepalive, (Plug) telnet, &telnet->cfg);
+    if ((err = sk_socket_error(telnet->s)) != NULL)
 	return err;
 
-    sk_addr_free(addr);
+    telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);
 
     /*
      * Initialise option states.
      */
-    if (cfg.passive_telnet) {
+    if (telnet->cfg.passive_telnet) {
 	const struct Opt *const *o;
 
 	for (o = opts; *o; o++)
@@ -714,36 +782,65 @@ static char *telnet_init(void *frontend_handle, void **backend_handle,
      */
     telnet->in_synch = FALSE;
 
+    /*
+     * We can send special commands from the start.
+     */
+    update_specials_menu(telnet->frontend);
+
     return NULL;
 }
 
+static void telnet_free(void *handle)
+{
+    Telnet telnet = (Telnet) handle;
+
+    sfree(telnet->sb_buf);
+    if (telnet->s)
+	sk_close(telnet->s);
+    if (telnet->pinger)
+	pinger_free(telnet->pinger);
+    sfree(telnet);
+}
+/*
+ * Reconfigure the Telnet backend. There's no immediate action
+ * necessary, in this backend: we just save the fresh config for
+ * any subsequent negotiations.
+ */
+static void telnet_reconfig(void *handle, Config *cfg)
+{
+    Telnet telnet = (Telnet) handle;
+    pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);
+    telnet->cfg = *cfg;		       /* STRUCTURE COPY */
+}
+
 /*
  * Called to send data down the Telnet connection.
  */
 static int telnet_send(void *handle, char *buf, int len)
 {
     Telnet telnet = (Telnet) handle;
-    char *p;
-    static unsigned char iac[2] = { IAC, IAC };
-    static unsigned char cr[2] = { CR, NUL };
+    unsigned char *p, *end;
+    static const unsigned char iac[2] = { IAC, IAC };
+    static const unsigned char cr[2] = { CR, NUL };
 #if 0
-    static unsigned char nl[2] = { CR, LF };
+    static const unsigned char nl[2] = { CR, LF };
 #endif
 
     if (telnet->s == NULL)
 	return 0;
 
-    p = buf;
-    while (p < buf + len) {
-	char *q = p;
+    p = (unsigned char *)buf;
+    end = (unsigned char *)(buf + len);
+    while (p < end) {
+	unsigned char *q = p;
 
-	while (iswritable((unsigned char) *p) && p < buf + len)
+	while (p < end && iswritable(*p))
 	    p++;
-	telnet->bufsize = sk_write(telnet->s, q, p - q);
+	telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
 
-	while (p < buf + len && !iswritable((unsigned char) *p)) {
+	while (p < end && !iswritable(*p)) {
 	    telnet->bufsize = 
-		sk_write(telnet->s, (unsigned char) *p == IAC ? iac : cr, 2);
+		sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
 	    p++;
 	}
     }
@@ -766,28 +863,34 @@ static int telnet_sendbuffer(void *handle)
 static void telnet_size(void *handle, int width, int height)
 {
     Telnet telnet = (Telnet) handle;
-    unsigned char b[16];
-    char logbuf[50];
+    unsigned char b[24];
+    int n;
+    char *logbuf;
 
     telnet->term_width = width;
     telnet->term_height = height;
 
     if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
 	return;
-    b[0] = IAC;
-    b[1] = SB;
-    b[2] = TELOPT_NAWS;
-    b[3] = telnet->term_width >> 8;
-    b[4] = telnet->term_width & 0xFF;
-    b[5] = telnet->term_height >> 8;
-    b[6] = telnet->term_height & 0xFF;
-    b[7] = IAC;
-    b[8] = SE;
-    telnet->bufsize = sk_write(telnet->s, b, 9);
-    sprintf(logbuf, "client:\tSB NAWS %d,%d",
-	    ((unsigned char) b[3] << 8) + (unsigned char) b[4],
-	    ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
+    n = 0;
+    b[n++] = IAC;
+    b[n++] = SB;
+    b[n++] = TELOPT_NAWS;
+    b[n++] = telnet->term_width >> 8;
+    if (b[n-1] == IAC) b[n++] = IAC;   /* duplicate any IAC byte occurs */
+    b[n++] = telnet->term_width & 0xFF;
+    if (b[n-1] == IAC) b[n++] = IAC;   /* duplicate any IAC byte occurs */
+    b[n++] = telnet->term_height >> 8;
+    if (b[n-1] == IAC) b[n++] = IAC;   /* duplicate any IAC byte occurs */
+    b[n++] = telnet->term_height & 0xFF;
+    if (b[n-1] == IAC) b[n++] = IAC;   /* duplicate any IAC byte occurs */
+    b[n++] = IAC;
+    b[n++] = SE;
+    telnet->bufsize = sk_write(telnet->s, (char *)b, n);
+    logbuf = dupprintf("client:\tSB NAWS %d,%d",
+		       telnet->term_width, telnet->term_height);
     logevent(telnet->frontend, logbuf);
+    sfree(logbuf);
 }
 
 /*
@@ -805,59 +908,64 @@ static void telnet_special(void *handle, Telnet_Special code)
     switch (code) {
       case TS_AYT:
 	b[1] = AYT;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_BRK:
 	b[1] = BREAK;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_EC:
 	b[1] = EC;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_EL:
 	b[1] = EL;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_GA:
 	b[1] = GA;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_NOP:
 	b[1] = NOP;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_ABORT:
 	b[1] = ABORT;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_AO:
 	b[1] = AO;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_IP:
 	b[1] = IP;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_SUSP:
 	b[1] = SUSP;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_EOR:
 	b[1] = EOR;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_EOF:
 	b[1] = xEOF;
-	telnet->bufsize = sk_write(telnet->s, b, 2);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	break;
       case TS_EOL:
-	telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
+	/* In BINARY mode, CR-LF becomes just CR -
+	 * and without the NUL suffix too. */
+	if (telnet->opt_states[o_we_bin.index] == ACTIVE)
+	    telnet->bufsize = sk_write(telnet->s, "\r", 1);
+	else
+	    telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
 	break;
       case TS_SYNCH:
 	b[1] = DM;
-	telnet->bufsize = sk_write(telnet->s, b, 1);
-	telnet->bufsize = sk_write_oob(telnet->s, b + 1, 1);
+	telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
+	telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
 	break;
       case TS_RECHO:
 	if (telnet->opt_states[o_echo.index] == INACTIVE ||
@@ -875,12 +983,37 @@ static void telnet_special(void *handle, Telnet_Special code)
       case TS_PING:
 	if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
 	    b[1] = NOP;
-	    telnet->bufsize = sk_write(telnet->s, b, 2);
+	    telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
 	}
 	break;
+      default:
+	break;	/* never heard of it */
     }
 }
 
+static const struct telnet_special *telnet_get_specials(void *handle)
+{
+    static const struct telnet_special specials[] = {
+	{"Are You There", TS_AYT},
+	{"Break", TS_BRK},
+	{"Synch", TS_SYNCH},
+	{"Erase Character", TS_EC},
+	{"Erase Line", TS_EL},
+	{"Go Ahead", TS_GA},
+	{"No Operation", TS_NOP},
+	{NULL, TS_SEP},
+	{"Abort Process", TS_ABORT},
+	{"Abort Output", TS_AO},
+	{"Interrupt Process", TS_IP},
+	{"Suspend Process", TS_SUSP},
+	{NULL, TS_SEP},
+	{"End Of Record", TS_EOR},
+	{"End Of File", TS_EOF},
+	{NULL, TS_EXITMENU}
+    };
+    return specials;
+}
+
 static Socket telnet_socket(void *handle)
 {
     Telnet telnet = (Telnet) handle;
@@ -922,17 +1055,31 @@ static void telnet_provide_logctx(void *handle, void *logctx)
 
 static int telnet_exitcode(void *handle)
 {
-    /* Telnet telnet = (Telnet) handle; */
-    /* Telnet doesn't transmit exit codes back to the client */
+    Telnet telnet = (Telnet) handle;
+    if (telnet->s != NULL)
+        return -1;                     /* still connected */
+    else
+        /* Telnet doesn't transmit exit codes back to the client */
+        return 0;
+}
+
+/*
+ * cfg_info for Telnet does nothing at all.
+ */
+static int telnet_cfg_info(void *handle)
+{
     return 0;
 }
 
 Backend telnet_backend = {
     telnet_init,
+    telnet_free,
+    telnet_reconfig,
     telnet_send,
     telnet_sendbuffer,
     telnet_size,
     telnet_special,
+    telnet_get_specials,
     telnet_socket,
     telnet_exitcode,
     telnet_sendok,
@@ -940,5 +1087,6 @@ Backend telnet_backend = {
     telnet_provide_ldisc,
     telnet_provide_logctx,
     telnet_unthrottle,
+    telnet_cfg_info,
     23
 };