Re: [PATCH] "ncat -l --send-only" not sending only

[Kris Katterjohn <katterjohn () gmail com>]

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David Fifield wrote:
> On Sat, Jun 27, 2009 at 08:08:37PM -0500, Kris Katterjohn wrote:
> > I created one patch to simply make Ncat behave like Netcat6 (which I think it
> > should do).  But I figured having a choice in the matter is a lot better
> > (since I seem to often have opinions on how things should behave which are
> > different than that of many list members), which lead me to my current patch
> > (attached) against the dev branch.  With this patch, --send-only's behavior
> > does not change; however, you can now use the new --send-only=force to make it
> > actually only send (or more specifically, not receive).
>
> I think that --send-only should work like the proposed
> --send-only=force. It should do what its name suggests, and doing it
> that way will probably simplify some code.

Great!

> The only thing is that I'm pretty sure connect and broker modes work the
> same way. Can you make another patch that makes --send-only work like
> Netcat6, with changes for connect and broker modes too?

Connect-mode already wouldn't read from the socket if --send-only was used,
but broker indeed had the same problem (I had just forgotten about it before).

I've attached a patch to have --send-only cause Ncat to not read from the
socket at all in plain listen and broker modes.

If you're curious, I put the checks for o.sendonly outside of the read_socket
and read_and_broadcast functions because 1) there's only one invocation of
them each so there isn't duplicated stuff and 2) while these read* functions
do more than just read (e.g. broadcasts, etc), it just felt sorta awkward
putting the checks inside.  It's not a big deal to do it either way though.

I should be able to commit this soon if there aren't any issues with it.

> David Fifield

Thanks,
Kris Katterjohn


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Index: ncat_listen.c
===================================================================
--- ncat_listen.c       (revision 13984)
+++ ncat_listen.c       (working copy)
@@ -207,7 +207,7 @@
                     if (o.sendonly)
                         goto quit;
                 }
-            } else {
+            } else if (!o.sendonly) {
                 /* Read from a client and write to stdout. */
                 if (read_socket(i) <= 0) {
                     if (!o.keepopen)
@@ -397,13 +397,11 @@
     if(o.linedelay)
         ncat_delay_timer(o.linedelay);
 
-    if (!o.sendonly) {
-        if (o.telnet)
-            dotelnet(recv_fd, (unsigned char *) buf, nbytes);
+    if (o.telnet)
+        dotelnet(recv_fd, (unsigned char *) buf, nbytes);
 
-        Write(STDOUT_FILENO, buf, nbytes);
-        ncat_log_recv(buf, nbytes);
-    }
+    Write(STDOUT_FILENO, buf, nbytes);
+    ncat_log_recv(buf, nbytes);
 
 #ifdef HAVE_OPENSSL
     /* SSL can buffer our input, so doing another select()
Index: ncat_broker.c
===================================================================
--- ncat_broker.c       (revision 13984)
+++ ncat_broker.c       (working copy)
@@ -192,7 +192,7 @@
             if (i == listen_socket) {
                 /* we have a new connection request */
                 handle_connection();
-            } else {
+            } else if (i == STDIN_FILENO || !o.sendonly) {
                 /* Handle incoming client data and distribute it. */
                 read_and_broadcast(i);
             }
@@ -355,11 +355,6 @@
 
             return;
         }
-
-        /* If we received from something other than stdin, and --send-only was
-           given, do no further processing. */
-        if (o.sendonly)
-            return;
     }
 
     if (o.debug > 1)


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