detect sendto error

1 files changed, 6 insertions, 2 deletions

diff --git a/gre.c b/gre.c
index 3a44d8c..40ea9f9 100644
--- a/gre.c
+++ b/gre.c
@@ -423,8 +423,12 @@ static int tun_cb(void)
         return -1;
     }
 
-    sendto(sock, frame, n, 0, (struct sockaddr *)&dest, remote_len);
-    return 0;
+    ssize_t res = sendto(sock, frame, n, 0, (struct sockaddr *)&dest, remote_len);
+    if (res < 0)
+    {
+        perror("sendto");
+    }
+    return res;
 }
 
 static int tun_new(short type, const char *dev)