Experimental Rlogin support, thanks to Delian Delchev. Local flow

control is unsupported, and server-to-client comms may fail for want
of working TCP Urgent.

[originally from svn r875]

rlogin.c

@@ -0,0 +1,149 @@
+#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "putty.h"
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+static Socket s = NULL;
+
+static void rlogin_size(void);
+
+static int sb_opt, sb_len;
+static char *sb_buf = NULL;
+static int sb_size = 0;
+#define SB_DELTA 1024
+
+static void c_write (char *buf, int len) {
+    from_backend(0, buf, len);
+}
+
+static int rlogin_receive (Socket s, int urgent, char *data, int len) {
+    if (!len) {
+	/* Connection has closed. */
+	sk_close(s);
+	s = NULL;
+	return 0;
+    }
+    if (urgent == 2) {
+        char c;
+        int i;
+        
+        c = *data++; len--;
+        if (c == 0x80)
+            rlogin_size();
+        /*
+         * We should flush everything (aka Telnet SYNCH) if we see
+         * 0x02, and we should turn off and on _local_ flow control
+         * on 0x10 and 0x20 respectively. I'm not convinced it's
+         * worth it...
+         */
+    }
+    c_write(data, len);
+    return 1;
+}
+
+/*
+ * Called to set up the rlogin connection.
+ * 
+ * Returns an error message, or NULL on success.
+ *
+ * Also places the canonical host name into `realhost'.
+ */
+static char *rlogin_init (char *host, int port, char **realhost) {
+    SockAddr addr;
+    char *err;
+
+    /*
+     * Try to find host.
+     */
+    addr = sk_namelookup(host, realhost);
+    if ( (err = sk_addr_error(addr)) )
+	return err;
+
+    if (port < 0)
+	port = 513;		       /* default rlogin port */
+
+    /*
+     * Open socket.
+     */
+    s = sk_new(addr, port, 1, rlogin_receive);
+    if ( (err = sk_socket_error(s)) )
+	return err;
+
+    sk_addr_free(addr);
+
+    /*
+     * Send local username, remote username, terminal/speed
+     */
+
+    {
+        char z = 0;
+        char *p;
+        sk_write(s, &z, 1);
+        sk_write(s, cfg.localusername, strlen(cfg.localusername));
+        sk_write(s, &z, 1);
+        sk_write(s, cfg.username, strlen(cfg.username));
+        sk_write(s, &z, 1);
+        sk_write(s, cfg.termtype, strlen(cfg.termtype));
+        sk_write(s, "/", 1);
+        for(p = cfg.termspeed; isdigit(*p); p++);
+        sk_write(s, cfg.termspeed, p - cfg.termspeed);
+        sk_write(s, &z, 1);
+    }
+
+    begin_session();
+
+    return NULL;
+}
+
+/*
+ * Called to send data down the rlogin connection.
+ */
+static void rlogin_send (char *buf, int len) {
+
+    if (s == NULL)
+	return;
+
+    sk_write(s, buf, len);
+}
+
+/*
+ * Called to set the size of the window
+ */
+static void rlogin_size(void) {
+    char b[12] = { 0xFF, 0xFF, 0x73, 0x73, 0, 0, 0, 0, 0, 0, 0, 0 };
+
+    b[6] = cols >> 8; b[7] = cols & 0xFF;
+    b[4] = rows >> 8; b[5] = rows & 0xFF;
+    sk_write(s, b, 12);
+    return;
+}
+
+/*
+ * Send rlogin special codes.
+ */
+static void rlogin_special (Telnet_Special code) {
+    /* Do nothing! */
+    return;
+}
+
+static Socket rlogin_socket(void) { return s; }
+
+static int rlogin_sendok(void) { return 1; }
+
+Backend rlogin_backend = {
+    rlogin_init,
+    rlogin_send,
+    rlogin_size,
+    rlogin_special,
+    rlogin_socket,
+    rlogin_sendok,
+    1
+};