X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/055817455466c8eb60392f30bb7c689763962e17..6226c9390d23d6868edde63b9568891cd88631cc:/telnet.c

diff --git a/telnet.c b/telnet.c
index 6789e5de..0d32f8c2 100644
--- a/telnet.c
+++ b/telnet.c
@@ -1,3 +1,7 @@
+/*
+ * Telnet backend.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -196,12 +200,10 @@ static const struct Opt o_tspeed =
     { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
 static const struct Opt o_ttype =
     { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
-static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
-    OPTINDEX_OENV, INACTIVE
-};
-static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
-    OPTINDEX_NENV, REQUESTED
-};
+static const struct Opt o_oenv =
+    { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
+static const struct Opt o_nenv =
+    { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
 static const struct Opt o_echo =
     { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
 static const struct Opt o_we_sga =
@@ -396,9 +398,12 @@ static void proc_rec_opt(Telnet telnet, int cmd, int option)
     }
     /*
      * If we reach here, the option was one we weren't prepared to
-     * cope with. So send a negative ack.
+     * cope with. If the request was positive (WILL or DO), we send
+     * a negative ack to indicate refusal. If the request was
+     * negative (WONT / DONT), we must do nothing.
      */
-    send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
+    if (cmd == WILL || cmd == DO)
+        send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
 }
 
 static void process_subneg(Telnet telnet)
@@ -638,6 +643,22 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
     }
 }
 
+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)
 {
@@ -649,10 +670,10 @@ static int telnet_closing(Plug plug, const char *error_msg, int error_code,
 	notify_remote_exit(telnet->frontend);
     }
     if (error_msg) {
-	/* A socket error has occurred. */
 	logevent(telnet->frontend, error_msg);
 	connection_fatal(telnet->frontend, "%s", error_msg);
-    }				       /* Otherwise, the remote side closed the connection normally. */
+    }
+    /* Otherwise, the remote side closed the connection normally. */
     return 0;
 }
 
@@ -685,6 +706,7 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
 			       int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
+	telnet_log,
 	telnet_closing,
 	telnet_receive,
 	telnet_sent
@@ -734,13 +756,6 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
     /*
      * Open socket.
      */
-    {
-	char *buf, addrbuf[100];
-	sk_getaddr(addr, addrbuf, 100);
-	buf = dupprintf("Connecting to %s port %d", addrbuf, port);
-	logevent(telnet->frontend, buf);
-	sfree(buf);
-    }
     telnet->s = new_connection(addr, *realhost, port, 0, 1,
 			       nodelay, keepalive, (Plug) telnet, &telnet->cfg);
     if ((err = sk_socket_error(telnet->s)) != NULL)
@@ -1004,10 +1019,10 @@ static const struct telnet_special *telnet_get_specials(void *handle)
     return specials;
 }
 
-static Socket telnet_socket(void *handle)
+static int telnet_connected(void *handle)
 {
     Telnet telnet = (Telnet) handle;
-    return telnet->s;
+    return telnet->s != NULL;
 }
 
 static int telnet_sendok(void *handle)
@@ -1070,7 +1085,7 @@ Backend telnet_backend = {
     telnet_size,
     telnet_special,
     telnet_get_specials,
-    telnet_socket,
+    telnet_connected,
     telnet_exitcode,
     telnet_sendok,
     telnet_ldisc,