From f17f6f0f42ce99c130618fa02b4e3955a461b622 Mon Sep 17 00:00:00 2001
From: Mikael Nousiainen <mikael.nousiainen@iki.fi>
Date: Wed, 8 Mar 2023 23:35:08 +0200
Subject: [PATCH] Disable rig port flushing when async I/O is enabled. Improve
 validation of Icom frames.

---
 rigs/icom/frame.c | 6 ++++++
 src/misc.c        | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/rigs/icom/frame.c b/rigs/icom/frame.c
index 081692705..9812b1e3a 100644
--- a/rigs/icom/frame.c
+++ b/rigs/icom/frame.c
@@ -530,6 +530,12 @@ static int read_icom_frame_generic(hamlib_port_t *p,
     while ((read < rxbuffer_len) && (rxbuffer[read - 1] != FI)
             && (rxbuffer[read - 1] != COL));
 
+    // Check that we have a valid frame preamble (which might be just a single preable character)
+    if (rxbuffer[0] != PR)
+    {
+        return -RIG_EPROTO;
+    }
+
     return (read);
 }
 
diff --git a/src/misc.c b/src/misc.c
index 6a7d34f34..41fe8d7eb 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -2147,6 +2147,12 @@ int HAMLIB_API parse_hoststr(char *hoststr, int hoststr_len, char host[256],
 //#define RIG_FLUSH_REMOVE
 int HAMLIB_API rig_flush(hamlib_port_t *port)
 {
+    // Data should never be flushed when using async I/O
+    if (port->asyncio)
+    {
+        return RIG_OK;
+    }
+
 #ifndef RIG_FLUSH_REMOVE
     rig_debug(RIG_DEBUG_TRACE, "%s: called for %s device\n", __func__,
               port->type.rig == RIG_PORT_SERIAL ? "serial" : "network");