Check TCP/UDP packet field presence

Some system uses "th_sum" and "uh_sum" for checksum fields while
other use "check".

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/tun.c b/tun.c
index 2711ba3..2b7f95b 100644
--- a/tun.c
+++ b/tun.c
@@ -1,4 +1,5 @@
 #define _GNU_SOURCE
+#include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -29,6 +30,20 @@
 #include "utils.h"
 #include "pcap.h"
 
+#ifndef HAVE_STRUCT_TCPHDR_TH_SUM
+#ifndef HAVE_STRUCT_TCPHDR_CHECK
+#error No checksum field found in tcphdr
+#endif
+#define th_sum check
+#endif
+
+#ifndef HAVE_STRUCT_UDPHDR_UH_SUM
+#ifndef HAVE_STRUCT_UDPHDR_CHECK
+#error No checksum field found in udphdr
+#endif
+#define uh_sum check
+#endif
+
 static int tun_fd = -1;
 static int tun_fd_back = -1;
 static int remote_sock = -1;