From 9cff4951838e915c48f1b0d2d1ac70e723ccdd8f Mon Sep 17 00:00:00 2001
From: Frank Rolsted Jensen <frj@thrane.eu>
Date: Thu, 28 Oct 2021 11:33:09 +0200
Subject: [PATCH] Support for software flow control

---
 src/telnet.h |  3 ++-
 src/ttynvt.c | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/telnet.h b/src/telnet.h
index c6a0ae4..213335e 100644
--- a/src/telnet.h
+++ b/src/telnet.h
@@ -60,11 +60,12 @@ extern void     telnet_rfc2217_ctl(tn_ctx_t * tcc, unsigned int val);
 
 /*RFC2217 control commands*/
 #define TNS_CTL_NOFLOW      1
-#define TNS_CTL_XONOFF      2
+#define TNS_CTL_XONOFF_OUT  2
 #define TNS_CTL_CTSRTS      3
 #define TNS_CTL_DTR_ON      8
 #define TNS_CTL_DTR_OFF     9
 #define TNS_CTL_RTS_ON     11
 #define TNS_CTL_RTS_OFF    12
+#define TNS_CTL_XONOFF_IN  15
 
 #endif /*TELNET_H */
diff --git a/src/ttynvt.c b/src/ttynvt.c
index 3e502cd..3cad949 100644
--- a/src/ttynvt.c
+++ b/src/ttynvt.c
@@ -855,6 +855,22 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
             tty->master_suspended = (tty->smcr & TIOCM_CTS) ? 0 : 1;
             telnet_rfc2217_ctl(tty->tn, TNS_CTL_CTSRTS);
         }
+        else if ((tio->c_iflag & IXON) && (tio->c_iflag & IXOFF))
+        {
+            tty->master_suspended = 0;
+            telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_OUT);
+            telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_IN);
+        }
+        else if (tio->c_iflag & IXON)
+        {
+            tty->master_suspended = 0;
+            telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_OUT);
+        }
+        else if (tio->c_iflag & IXOFF)
+        {
+            tty->master_suspended = 0;
+            telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_IN);
+        }
         else
         {
             tty->master_suspended = 0;