From efd8d7378b539a479b479582c59f798815fa613f Mon Sep 17 00:00:00 2001
From: wangyu <wangyucn@gmail.com>
Date: Tue, 11 Jul 2017 18:05:00 +0800
Subject: [PATCH] 7.11 commit

---
 main.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/main.cpp b/main.cpp
index 103afc2..07cb356 100644
--- a/main.cpp
+++ b/main.cpp
@@ -682,11 +682,20 @@ int on_raw_recv()
 
 	size = recvfrom(raw_recv_fd, buf, buf_len, 0 ,&saddr , &saddr_size);
 
+	if(buf[13]!=8||buf[14]!=0)
+	{
+		printf("not an ipv4 packet!\n");
+		fflush(stdout);
+		return 0;
+	}
+
 	char *ip_data=buf+14;
 
 	struct iphdr *iph = (struct iphdr *) (ip_data);
 
 
+
+
     if (!(iph->ihl > 0 && iph->ihl < (MTU)/4)) {
     	printf("iph ihl error");
     	fflush(stdout);