X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/32874aeac8dacbca26663777b39a79efc5d8dc4b..247308b5cf8a51eba882abf13c5572ba8f83d0ea:/telnet.c

diff --git a/telnet.c b/telnet.c
index b2e49994..8ce3cf4f 100644
--- a/telnet.c
+++ b/telnet.c
@@ -174,8 +174,11 @@ static struct Opt *opts[] = {
     &o_we_sga, &o_they_sga, NULL
 };
 
-static int echoing = TRUE, editing = TRUE;
+#define TELNET_MAX_BACKLOG 4096
 
+static int echoing = TRUE, editing = TRUE;
+static int activated = FALSE;
+static int telnet_bufsize;
 static int in_synch;
 static int sb_opt, sb_len;
 static char *sb_buf = NULL;
@@ -184,8 +187,10 @@ static int sb_size = 0;
 
 static void c_write1(int c)
 {
+    int backlog;
     char cc = (char) c;
-    from_backend(0, &cc, 1);
+    backlog = from_backend(0, &cc, 1);
+    sk_set_frozen(s, backlog > TELNET_MAX_BACKLOG);
 }
 
 static void log_option(char *sender, int cmd, int option)
@@ -205,7 +210,7 @@ static void send_opt(int cmd, int option)
     b[0] = IAC;
     b[1] = cmd;
     b[2] = option;
-    sk_write(s, b, 3);
+    telnet_bufsize = sk_write(s, b, 3);
     log_option("client", cmd, option);
 }
 
@@ -225,7 +230,24 @@ static void option_side_effects(struct Opt *o, int enabled)
 	echoing = !enabled;
     else if (o->option == TELOPT_SGA && o->send == DO)
 	editing = !enabled;
-    ldisc_send(NULL, 0);	       /* cause ldisc to notice the change */
+    ldisc_send(NULL, 0, 0);	       /* cause ldisc to notice the change */
+
+    /* Ensure we get the minimum options */
+    if (!activated) {
+	if (o_echo.state == INACTIVE) {
+	    o_echo.state = REQUESTED;
+	    send_opt(o_echo.send, o_echo.option);
+	}
+	if (o_we_sga.state == INACTIVE) {
+	    o_we_sga.state = REQUESTED;
+	    send_opt(o_we_sga.send, o_we_sga.option);
+	}
+	if (o_they_sga.state == INACTIVE) {
+	    o_they_sga.state = REQUESTED;
+	    send_opt(o_they_sga.send, o_they_sga.option);
+	}
+	activated = TRUE;
+    }
 }
 
 static void activate_option(struct Opt *o)
@@ -322,7 +344,7 @@ static void process_subneg(void)
 	    n = 4 + strlen(cfg.termspeed);
 	    b[n] = IAC;
 	    b[n + 1] = SE;
-	    sk_write(s, b, n + 2);
+	    telnet_bufsize = sk_write(s, b, n + 2);
 	    logevent("server:\tSB TSPEED SEND");
 	    sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
 	    logevent(logbuf);
@@ -343,7 +365,7 @@ static void process_subneg(void)
 			    'a' : cfg.termtype[n]);
 	    b[n + 4] = IAC;
 	    b[n + 5] = SE;
-	    sk_write(s, b, n + 6);
+	    telnet_bufsize = sk_write(s, b, n + 6);
 	    b[n + 4] = 0;
 	    logevent("server:\tSB TTYPE SEND");
 	    sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
@@ -419,7 +441,7 @@ static void process_subneg(void)
 	    }
 	    b[n++] = IAC;
 	    b[n++] = SE;
-	    sk_write(s, b, n);
+	    telnet_bufsize = sk_write(s, b, n);
 	    sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
 		    n == 6 ? "<nothing>" : "<stuff>");
 	    logevent(logbuf);
@@ -547,11 +569,14 @@ static void do_telnet_read(char *buf, int len)
 static int telnet_closing(Plug plug, char *error_msg, int error_code,
 			  int calling_back)
 {
-    sk_close(s);
-    s = NULL;
+    if (s) {
+        sk_close(s);
+        s = NULL;
+    }
     if (error_msg) {
 	/* A socket error has occurred. */
-	connection_fatal(error_msg);
+	logevent(error_msg);
+	connection_fatal("%s", error_msg);
     }				       /* Otherwise, the remote side closed the connection normally. */
     return 0;
 }
@@ -564,18 +589,25 @@ static int telnet_receive(Plug plug, int urgent, char *data, int len)
     return 1;
 }
 
+static void telnet_sent(Plug plug, int bufsize)
+{
+    telnet_bufsize = bufsize;
+}
+
 /*
  * Called to set up the Telnet connection.
  *
  * Returns an error message, or NULL on success.
  *
- * Also places the canonical host name into `realhost'.
+ * Also places the canonical host name into `realhost'. It must be
+ * freed by the caller.
  */
-static char *telnet_init(char *host, int port, char **realhost)
+static char *telnet_init(char *host, int port, char **realhost, int nodelay)
 {
     static struct plug_function_table fn_table = {
 	telnet_closing,
-	telnet_receive
+	telnet_receive,
+	telnet_sent
     }, *fn_table_ptr = &fn_table;
 
     SockAddr addr;
@@ -584,6 +616,11 @@ static char *telnet_init(char *host, int port, char **realhost)
     /*
      * Try to find host.
      */
+    {
+	char buf[200];
+	sprintf(buf, "Looking up host \"%.170s\"", host);
+	logevent(buf);
+    }
     addr = sk_namelookup(host, realhost);
     if ((err = sk_addr_error(addr)))
 	return err;
@@ -594,7 +631,13 @@ static char *telnet_init(char *host, int port, char **realhost)
     /*
      * Open socket.
      */
-    s = sk_new(addr, port, 0, 1, &fn_table_ptr);
+    {
+	char buf[200], addrbuf[100];
+	sk_getaddr(addr, addrbuf, 100);
+	sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
+	logevent(buf);
+    }
+    s = new_connection(addr, *realhost, port, 0, 1, nodelay, &fn_table_ptr);
     if ((err = sk_socket_error(s)))
 	return err;
 
@@ -603,12 +646,19 @@ static char *telnet_init(char *host, int port, char **realhost)
     /*
      * Initialise option states.
      */
-    {
+    if (cfg.passive_telnet) {
+	struct Opt **o;
+
+	for (o = opts; *o; o++)
+	    if ((*o)->state == REQUESTED)
+		(*o)->state = INACTIVE;
+    } else {
 	struct Opt **o;
 
 	for (o = opts; *o; o++)
 	    if ((*o)->state == REQUESTED)
 		send_opt((*o)->send, (*o)->option);
+	activated = TRUE;
     }
 
     /*
@@ -622,15 +672,17 @@ static char *telnet_init(char *host, int port, char **realhost)
 /*
  * Called to send data down the Telnet connection.
  */
-static void telnet_send(char *buf, int len)
+static int telnet_send(char *buf, int len)
 {
     char *p;
     static unsigned char iac[2] = { IAC, IAC };
     static unsigned char cr[2] = { CR, NUL };
+#if 0
     static unsigned char nl[2] = { CR, LF };
+#endif
 
     if (s == NULL)
-	return;
+	return 0;
 
     p = buf;
     while (p < buf + len) {
@@ -638,13 +690,24 @@ static void telnet_send(char *buf, int len)
 
 	while (iswritable((unsigned char) *p) && p < buf + len)
 	    p++;
-	sk_write(s, q, p - q);
+	telnet_bufsize = sk_write(s, q, p - q);
 
 	while (p < buf + len && !iswritable((unsigned char) *p)) {
-	    sk_write(s, (unsigned char) *p == IAC ? iac : nl, 2);
+	    telnet_bufsize = 
+		sk_write(s, (unsigned char) *p == IAC ? iac : cr, 2);
 	    p++;
 	}
     }
+
+    return telnet_bufsize;
+}
+
+/*
+ * Called to query the current socket sendability status.
+ */
+static int telnet_sendbuffer(void)
+{
+    return telnet_bufsize;
 }
 
 /*
@@ -666,7 +729,7 @@ static void telnet_size(void)
     b[6] = rows & 0xFF;
     b[7] = IAC;
     b[8] = SE;
-    sk_write(s, b, 9);
+    telnet_bufsize = sk_write(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]);
@@ -687,56 +750,59 @@ static void telnet_special(Telnet_Special code)
     switch (code) {
       case TS_AYT:
 	b[1] = AYT;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_BRK:
 	b[1] = BREAK;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_EC:
 	b[1] = EC;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_EL:
 	b[1] = EL;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_GA:
 	b[1] = GA;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_NOP:
 	b[1] = NOP;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_ABORT:
 	b[1] = ABORT;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_AO:
 	b[1] = AO;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_IP:
 	b[1] = IP;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_SUSP:
 	b[1] = SUSP;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_EOR:
 	b[1] = EOR;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
 	break;
       case TS_EOF:
 	b[1] = xEOF;
-	sk_write(s, b, 2);
+	telnet_bufsize = sk_write(s, b, 2);
+	break;
+      case TS_EOL:
+	telnet_bufsize = sk_write(s, "\r\n", 2);
 	break;
       case TS_SYNCH:
 	b[1] = DM;
-	sk_write(s, b, 1);
-	sk_write_oob(s, b + 1, 1);
+	telnet_bufsize = sk_write(s, b, 1);
+	telnet_bufsize = sk_write_oob(s, b + 1, 1);
 	break;
       case TS_RECHO:
 	if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
@@ -753,7 +819,7 @@ static void telnet_special(Telnet_Special code)
       case TS_PING:
 	if (o_they_sga.state == ACTIVE) {
 	    b[1] = NOP;
-	    sk_write(s, b, 2);
+	    telnet_bufsize = sk_write(s, b, 2);
 	}
 	break;
     }
@@ -769,6 +835,11 @@ static int telnet_sendok(void)
     return 1;
 }
 
+static void telnet_unthrottle(int backlog)
+{
+    sk_set_frozen(s, backlog > TELNET_MAX_BACKLOG);
+}
+
 static int telnet_ldisc(int option)
 {
     if (option == LD_ECHO)
@@ -778,13 +849,22 @@ static int telnet_ldisc(int option)
     return FALSE;
 }
 
+static int telnet_exitcode(void)
+{
+    /* Telnet doesn't transmit exit codes back to the client */
+    return 0;
+}
+
 Backend telnet_backend = {
     telnet_init,
     telnet_send,
+    telnet_sendbuffer,
     telnet_size,
     telnet_special,
     telnet_socket,
+    telnet_exitcode,
     telnet_sendok,
     telnet_ldisc,
+    telnet_unthrottle,
     23
 };