From b21cc278ce2b88503ea97a05f552001aef632f3d Mon Sep 17 00:00:00 2001
From: russor <russor@whatsapp.com>
Date: Mon, 18 Apr 2016 15:22:50 -0700
Subject: [PATCH] correct checksum calculation when adding the overflow
 overflows

you can see this with a bit pattern of FF and a large packet length
---
 net.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net.c b/net.c
index f743492..60b2b68 100644
--- a/net.c
+++ b/net.c
@@ -247,8 +247,9 @@ int checksum(void *data, int sz)
   while (sz--) {
     sum += *(ch++);
   }
-  
-  sum = (sum >> 16) + (sum & 0xffff);  
+  while (sum >> 16) {
+    sum = (sum >> 16) + (sum & 0xffff);
+  }
 
   return (~sum & 0xffff);  
 }
-- 
2.47.2