From 54d6324dea2e89ee00ef4f24ca11a1ce5c1cda99 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Wed, 23 Sep 2020 09:12:14 -0500
Subject: [PATCH] Fix invalid return in patty_ax25_aprs_is_send()

Fix invalid return in patty_ax25_aprs_is_send() wherein the number of
bytes written to APRS-IS was returned, rather than the number of AX.25
packet bytes; the number of bytes read is the more important value as it
is used later for repeating the frame to promiscuous mode SOCK_RAW
sockets
---
 src/aprs_is.c | 58 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 34 insertions(+), 24 deletions(-)

diff --git a/src/aprs_is.c b/src/aprs_is.c
index fa4da9b..bf10265 100644
--- a/src/aprs_is.c
+++ b/src/aprs_is.c
@@ -320,24 +320,30 @@ ssize_t patty_ax25_aprs_is_send(patty_ax25_aprs_is *aprs,
                                 size_t len) {
     patty_ax25_frame frame;
 
-    size_t offset = 0;
+    size_t i = 0,
+           o = 0,
+           hop;
+
     ssize_t decoded;
 
-    int formatted,
-        i;
+    int formatted;
 
     char call[PATTY_AX25_ADDRSTRLEN+1];
 
     if ((decoded = patty_ax25_frame_decode_address(&frame, buf, len)) < 0) {
         goto error;
+    } else {
+        i += decoded;
     }
 
-    if (patty_ax25_frame_decode_control(&frame,
-                                        PATTY_AX25_FRAME_NORMAL,
-                                        buf,
-                                        decoded,
-                                        len) < 0) {
+    if ((decoded = patty_ax25_frame_decode_control(&frame,
+                                                   PATTY_AX25_FRAME_NORMAL,
+                                                   buf,
+                                                   i,
+                                                   len)) < 0) {
         goto error;
+    } else {
+        i += decoded;
     }
 
     if (!PATTY_AX25_FRAME_CONTROL_UI(frame.control)) {
@@ -354,55 +360,59 @@ ssize_t patty_ax25_aprs_is_send(patty_ax25_aprs_is *aprs,
                               call)) < 0) {
         goto error;
     } else {
-        offset += formatted;
+        o += formatted;
     }
 
     if (patty_ax25_ntop(&frame.dest, call, sizeof(call)) < 0) {
         goto error;
     }
 
-    if ((formatted = snprintf(aprs->tx_buf + offset,
-                              aprs->tx_bufsz - offset,
+    if ((formatted = snprintf(aprs->tx_buf + o,
+                              aprs->tx_bufsz - o,
                               "%s",
                               call)) < 0) {
         goto error;
     } else {
-        offset += formatted;
+        o += formatted;
     }
 
-    for (i=0; i<frame.hops; i++) {
-        if (patty_ax25_ntop(&frame.repeaters[i],
+    for (hop=0; hop<frame.hops; hop++) {
+        if (patty_ax25_ntop(&frame.repeaters[hop],
                             call,
                             sizeof(call)) < 0) {
             goto error;
         }
 
-        if ((formatted = snprintf(aprs->tx_buf + offset,
-                                  aprs->tx_bufsz - offset,
+        if ((formatted = snprintf(aprs->tx_buf + o,
+                                  aprs->tx_bufsz - o,
                                   ",%s",
                                   call)) < 0) {
             goto error;
         } else {
-            offset += formatted;
+            o += formatted;
         }
     }
 
-    if (aprs->tx_bufsz - offset < frame.infolen + 3) {
+    if (aprs->tx_bufsz < o + frame.infolen + 3) {
         errno = EOVERFLOW;
 
         goto error;
     }
 
-    aprs->tx_buf[offset++] = ':';
+    aprs->tx_buf[o++] = ':';
 
-    memcpy(aprs->tx_buf + offset, frame.info, frame.infolen);
+    memcpy(aprs->tx_buf + o, frame.info, frame.infolen);
 
-    offset += frame.infolen;
+    o += frame.infolen;
 
-    aprs->tx_buf[offset++] = '\r';
-    aprs->tx_buf[offset++] = '\n';
+    aprs->tx_buf[o++] = '\r';
+    aprs->tx_buf[o++] = '\n';
 
-    return write(aprs->fd, aprs->tx_buf, offset);
+    if (write(aprs->fd, aprs->tx_buf, o) < 0) {
+        goto error;
+    }
+
+    return i;
 
 error:
     return -1;