Change negotiation of ECHO for dumb 4.2 telnets

SCCS-vsn: libexec/telnetd/telnetd.c 5.39

diff --git a/usr/src/libexec/telnetd/telnetd.c b/usr/src/libexec/telnetd/telnetd.c
index 2f07a87..c649a68 100644 (file)
--- a/usr/src/libexec/telnetd/telnetd.c
+++ b/usr/src/libexec/telnetd/telnetd.c
@@ -22,7 +22,7 @@ char copyright[] =
 #endif /* not lint */
 
 #ifndef lint
 #endif /* not lint */
 
 #ifndef lint

-static char sccsid[] = "@(#)telnetd.c  5.38 (Berkeley) %G%";
+static char sccsid[] = "@(#)telnetd.c  5.39 (Berkeley) %G%";

 #endif /* not lint */
 
 #include "telnetd.h"
 #endif /* not lint */
 
 #include "telnetd.h"


@@ -368,8 +368,6 @@ int f, p;
         * Rather than doing them slowly, one at a time, do them all
         * at once.
         */
         * Rather than doing them slowly, one at a time, do them all
         * at once.
         */

-       if (!myopts[TELOPT_ECHO])
-               dooption(TELOPT_ECHO);

        if (!myopts[TELOPT_SGA])
                dooption(TELOPT_SGA);
        /*
        if (!myopts[TELOPT_SGA])
                dooption(TELOPT_SGA);
        /*


@@ -415,6 +413,27 @@ int f, p;
        while (hiswants[TELOPT_NAWS] != hisopts[TELOPT_NAWS])
                ttloop();
 
        while (hiswants[TELOPT_NAWS] != hisopts[TELOPT_NAWS])
                ttloop();
 

+       /*
+        * On the off chance that the telnet client is broken and does not
+        * respond to the DO ECHO we sent, (after all, we did send the
+        * DO NAWS negotiation after the DO ECHO, and we won't get here
+        * until a response to the DO NAWS comes back) simulate the
+        * receipt of a will echo.  This will also send a WONT ECHO
+        * to the client, since we assume that the client failed to
+        * respond because it believes that it is already in DO ECHO
+        * mode, which we do not want.
+        */
+       if (hiswants[TELOPT_ECHO] == OPT_YES)
+               willoption(TELOPT_ECHO, 0);
+
+       /*
+        * Finally, to clean things up, we turn on our echo.  This
+        * will break stupid 4.2 telnets out of local terminal echo.
+        */
+
+       if (!myopts[TELOPT_ECHO])
+               dooption(TELOPT_ECHO);
+

        /*
         * Turn on packet mode, and default to line at at time mode.
         */
        /*
         * Turn on packet mode, and default to line at at time mode.
         */