From ec7b3af1399bf0714eb0e6ccc2fdab2a44cd01ca Mon Sep 17 00:00:00 2001
From: Un1q32 <joey.t.reinhart@gmail.com>
Date: Fri, 25 Apr 2025 01:59:17 -0400
Subject: [PATCH] add comment

---
 oc2rnet.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/oc2rnet.c b/oc2rnet.c
index 43a1b88..e1b2111 100644
--- a/oc2rnet.c
+++ b/oc2rnet.c
@@ -8,7 +8,9 @@
 #include <stdio.h>
 #endif
 
-#ifdef __APPLE__
+#if defined(__linux__) || defined(__APPLE__)
+
+#ifndef __linux__
 static uint16_t checksum(void *b, int len) {
   uint16_t *buf = b;
   uint32_t sum = 0;
@@ -24,8 +26,6 @@ static uint16_t checksum(void *b, int len) {
 }
 #endif
 
-#if defined(__linux__) || defined(__APPLE__)
-
 #include <sys/types.h>
 
 #include <netinet/ip.h>
@@ -65,9 +65,9 @@ static ssize_t doPing(uint32_t ip, size_t size, char *data, char *response,
   packet->icmp_code = 0;
   packet->icmp_id = getpid() & 0xFFFF;
   packet->icmp_seq = 1;
-  packet->icmp_cksum = 0;
   memcpy(packet->icmp_data, data, size);
-#ifdef __APPLE__
+#ifndef __linux__ // Linux ignores and recalculates the checksum for us
+  packet->icmp_cksum = 0;
   packet->icmp_cksum = checksum(packet, packet_size);
 #endif