From 5fe656762fa8a198447e6372b6e6c417e0613f36 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Sat, 18 Jul 2015 02:41:42 -0500
Subject: [PATCH] At least now, we can discern between commands and responses

---
 include/patty/ax25.h |  6 ++++++
 src/ax25.c           | 14 ++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/patty/ax25.h b/include/patty/ax25.h
index 9f3281b..3a14532 100644
--- a/include/patty/ax25.h
+++ b/include/patty/ax25.h
@@ -38,6 +38,11 @@ enum patty_ax25_frame_type {
     PATTY_AX25_FRAME_UNNUMBERED
 };
 
+enum patty_ax25_frame_cr {
+    PATTY_AX25_FRAME_COMMAND,
+    PATTY_AX25_FRAME_RESPONSE
+};
+
 typedef struct _patty_ax25_address {
     char callsign[7];
 
@@ -60,6 +65,7 @@ typedef struct _patty_ax25_frame {
 
     enum patty_ax25_version    version;
     enum patty_ax25_frame_type type;
+    enum patty_ax25_frame_cr   cr;
 
     uint8_t control;
     uint8_t proto;
diff --git a/src/ax25.c b/src/ax25.c
index 3d75a64..bc0ca2a 100644
--- a/src/ax25.c
+++ b/src/ax25.c
@@ -121,6 +121,20 @@ static ssize_t frame_decode_address(patty_ax25_frame *frame, void *data, off_t s
         offset += decoded;
     }
 
+    /*
+     * Determine whether the current frame is a Command or Response, and which
+     * version of AX.25 this frame adheres to.
+     */
+    if (PATTY_AX25_ADDRESS_SSID_C(frame->src.ssid)) {
+        frame->cr      = PATTY_AX25_FRAME_RESPONSE;
+        frame->version = PATTY_AX25_ADDRESS_SSID_C(frame->dest.ssid)?
+            PATTY_AX25_OLD: PATTY_AX25_2_0;
+    } else {
+        frame->cr      = PATTY_AX25_FRAME_COMMAND;
+        frame->version = PATTY_AX25_ADDRESS_SSID_C(frame->src.ssid)?
+            PATTY_AX25_OLD: PATTY_AX25_2_0;
+    }
+
     /*
      * If the source address is not the final address in the frame, begin
      * decoding repeater addresses.