netfilter sk_buff tcphdr 端口屏蔽问题？？
时间：2010-11-07
来源：互联网
我是想屏蔽某些端口 (21)
复制代码
然后我测试连接21端口
#nc -v xx.xx.xx.xx 21
没有成功，还是连接上了，端口没被屏蔽
然后我用printk查看具体端口号
插入三天printk
printk(KERN_INFO "Packet from source port %d \n",tcph->dest);
printk(KERN_INFO "Packet from dest port %d \n",tcph->source);
printk(KERN_INFO "Packet from match port %d \n",*(__be16 *)deny_port);
复制代码
打印结果如下
命令
nc -v xx.xx.xx.xx 21
[14004.353389] Packet from source port 5376 //源端口
[14004.353394] Packet from dest port 1934 //目的端口
[14004.353397] Packet from match port 21 //我要批评的端口
[14004.431504] Packet from source port 5376
[14004.431508] Packet from dest port 1934
[14004.431510] Packet from match port 21
这是什么原因呢？
- static unsigned char *deny_port = "\x15\x00";//port 21
-
- …
- struct sk_buff *sb = skb;
- struct tcphdr *tcph;
-
- tcph=tcp_hdr(sb);
- if(tcph->source==*(__be16 *)deny_port)
- {
- printk(KERN_INFO "Packet from port 21 Droped\n");
- return NF_DROP;
- }
-
- …
#nc -v xx.xx.xx.xx 21
没有成功，还是连接上了，端口没被屏蔽
然后我用printk查看具体端口号
插入三天printk
printk(KERN_INFO "Packet from source port %d \n",tcph->dest);
printk(KERN_INFO "Packet from dest port %d \n",tcph->source);
printk(KERN_INFO "Packet from match port %d \n",*(__be16 *)deny_port);
- struct sk_buff *sb = skb;
- struct tcphdr *tcph;
-
- tcph=tcp_hdr(sb);
-
- printk(KERN_INFO "Packet from source port %d \n",tcph->dest);
- printk(KERN_INFO "Packet from dest port %d \n",tcph->source);
- printk(KERN_INFO "Packet from match port %d \n",*(__be16 *)deny_port);
-
- if(tcph->source==*(__be16 *)deny_port)
- {
- printk(KERN_INFO "Packet from port 21 Droped\n");
- return NF_DROP;
- }
命令
nc -v xx.xx.xx.xx 21
[14004.353389] Packet from source port 5376 //源端口
[14004.353394] Packet from dest port 1934 //目的端口
[14004.353397] Packet from match port 21 //我要批评的端口
[14004.431504] Packet from source port 5376
[14004.431508] Packet from dest port 1934
[14004.431510] Packet from match port 21
这是什么原因呢？
作者: Linux386 发布时间: 2010-11-07
0x1500 == 0x0015
对楼主极度无语
对楼主极度无语
作者: beyond_touch 发布时间: 2010-11-07
相关阅读 更多
热门阅读
-
office 2019专业增强版最新2021版激活秘钥/序列号/激活码推荐 附激活工具
阅读：74
-
如何安装mysql8.0
阅读：31
-
Word快速设置标题样式步骤详解
阅读：28
-
20+道必知必会的Vue面试题（附答案解析）
阅读：37
-
HTML如何制作表单
阅读：22
-
百词斩可以改天数吗？当然可以，4个步骤轻松修改天数！
阅读：31
-
ET文件格式和XLS格式文件之间如何转化？
阅读：24
-
react和vue的区别及优缺点是什么
阅读：121
-
支付宝人脸识别如何关闭?
阅读：21
-
腾讯微云怎么修改照片或视频备份路径?
阅读：28
