From c8c00c994c9a9adf1a480aaf6a7110e12f36fc15 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Tue, 22 Sep 2020 16:30:05 -0400
Subject: [PATCH] Handle non-DATA KISS commands in src/tnc.c

Handle non-DATA KISS commands in src/tnc.c, rather than simply returning
-1 setting errno to EIO
---
 src/tnc.c | 45 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 11 deletions(-)

diff --git a/src/tnc.c b/src/tnc.c
index 09a60ef..fc909f5 100644
--- a/src/tnc.c
+++ b/src/tnc.c
@@ -23,7 +23,7 @@ enum tnc_opts {
 
 enum state {
     KISS_NONE,
-    KISS_FRAME,
+    KISS_FRAME_COMMAND,
     KISS_FRAME_BODY,
     KISS_FRAME_ESCAPE
 };
@@ -40,6 +40,7 @@ struct _patty_kiss_tnc {
     void *buf;
 
     enum state state;
+    enum patty_kiss_command command;
 
     size_t bufsz,
            readlen,
@@ -149,6 +150,7 @@ patty_kiss_tnc *patty_kiss_tnc_new(patty_kiss_tnc_info *info) {
 
     tnc->opts     = TNC_NONE;
     tnc->state    = KISS_NONE;
+    tnc->command  = PATTY_KISS_RETURN;
     tnc->bufsz    = PATTY_KISS_TNC_BUFSZ;
     tnc->offset_i = 0;
     tnc->offset_o = 0;
@@ -240,21 +242,35 @@ ssize_t patty_kiss_tnc_drain(patty_kiss_tnc *tnc, void *buf, size_t len) {
         switch (tnc->state) {
             case KISS_NONE:
                 if (c == PATTY_KISS_FEND) {
-                    tnc->state = KISS_FRAME;
+                    tnc->state = KISS_FRAME_COMMAND;
                 }
 
                 break;
 
-            case KISS_FRAME:
+            case KISS_FRAME_COMMAND:
                 if (c == PATTY_KISS_FEND) {
                     break;
-                } else if (PATTY_KISS_COMMAND(c) != PATTY_KISS_DATA) {
-                    errno = EIO;
-
-                    goto error_io;
                 }
 
-                tnc->state = KISS_FRAME_BODY;
+                switch (c) {
+                    case PATTY_KISS_DATA:
+                    case PATTY_KISS_TXDELAY:
+                    case PATTY_KISS_PERSISTENCE:
+                    case PATTY_KISS_SLOT_TIME:
+                    case PATTY_KISS_TX_TAIL:
+                    case PATTY_KISS_FULL_DUPLEX:
+                    case PATTY_KISS_HW_SET:
+                    case PATTY_KISS_RETURN:
+                        break;
+
+                    default:
+                        errno = EIO;
+
+                        goto error_io;
+                }
+
+                tnc->state   = KISS_FRAME_BODY;
+                tnc->command = (enum patty_kiss_command)c;
 
                 break;
 
@@ -262,11 +278,17 @@ ssize_t patty_kiss_tnc_drain(patty_kiss_tnc *tnc, void *buf, size_t len) {
                 if (c == PATTY_KISS_FESC) {
                     tnc->state = KISS_FRAME_ESCAPE;
                 } else if (c == PATTY_KISS_FEND) {
-                    tnc->state = KISS_FRAME;
+                    tnc->state = KISS_FRAME_COMMAND;
 
                     goto done;
                 } else {
-                    ((uint8_t *)buf)[tnc->offset_o++] = c;
+                    switch (tnc->command) {
+                        case PATTY_KISS_DATA:
+                            ((uint8_t *)buf)[tnc->offset_o++] = c;
+
+                        default:
+                            break;
+                    }
                 }
 
                 break;
@@ -294,7 +316,7 @@ error_io:
 }
 
 int patty_kiss_tnc_ready(patty_kiss_tnc *tnc) {
-    return tnc->state == KISS_FRAME && tnc->offset_o > 0? 1: 0;
+    return tnc->state == KISS_FRAME_COMMAND && tnc->offset_o > 0? 1: 0;
 }
 
 ssize_t patty_kiss_tnc_flush(patty_kiss_tnc *tnc) {
@@ -302,6 +324,7 @@ ssize_t patty_kiss_tnc_flush(patty_kiss_tnc *tnc) {
         ssize_t ret = (ssize_t)tnc->offset_o;
 
         tnc->state    = KISS_NONE;
+        tnc->command  = PATTY_KISS_RETURN;
         tnc->offset_o = 0;
 
         return ret;