From: russor <russor@whatsapp.com>
Date: Fri, 8 Apr 2016 23:34:26 +0000 (-0700)
Subject: fix checksum for odd sized packets
X-Git-Tag: v0.87~12^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6f06bc68042cdc8e6d889649f4ad48ea0ac62d71;p=thirdparty%2Fmtr.git

fix checksum for odd sized packets
---

diff --git a/net.c b/net.c
index 4806825..529f496 100644
--- a/net.c
+++ b/net.c
@@ -231,15 +231,19 @@ int calc_deltatime (float waittime)
 }
 
 
-/* This doesn't work for odd sz. I don't know enough about this to say
-   that this is wrong. It doesn't seem to cripple mtr though. -- REW */
 int checksum(void *data, int sz) 
 {
   unsigned short *ch;
   unsigned int sum;
+  char odd[2];
 
   sum = 0;
   ch = data;
+  if (sz % 2) {
+    odd[0] = ((char*)data)[sz - 1];
+    odd[1] = 0;
+    sum = *(unsigned short*)(void*)&odd;
+  }
   sz = sz / 2;
   while (sz--) {
     sum += *(ch++);