netfilter_queue
来源:互联网 发布:金融it行业是投行it 编辑:程序博客网 时间:2024/05/16 00:54
1. 官方资源
官方网址是:http://netfilter.org/projects/libnetfilter_queue/
截止2017年2月16日,最新版本是1.0.2 , 这个版本的依赖libnfnetlink和libmnl并要求linux内核 2.6.14以上.
比较早的版本1.0.1多一个libmnl. 这些也体现在示例代码里。
2. 安装与设置
下载完源码后,先安装libnfnetlink和libmnl,再安装netfilter_queue
2.1 编译
configure, make ,make install (注意make install的时候需要sudo)
2.2 检查
在安装完所有库之后,我们可以到/usr/local/include查看这三个库的头文件是否存在,他们的目录分别是”libmnl”, “libnetfilter_queue”和”libnfnetlink”.
3. 样例代码
3.1 netfilter_queue 1.0.2版本的样例代码在 libnetfilter_queue-1.0.2/examples里”nf-queue.c”, 如下:
#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <time.h>#include <arpa/inet.h>#include <libmnl/libmnl.h>#include <linux/netfilter.h>#include <linux/netfilter/nfnetlink.h>#include <linux/types.h>#include <linux/netfilter/nfnetlink_queue.h>#include <libnetfilter_queue/libnetfilter_queue.h>static struct mnl_socket *nl;static struct nlmsghdr *nfq_hdr_put(char *buf, int type, uint32_t queue_num){ struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf); nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | type; nlh->nlmsg_flags = NLM_F_REQUEST; struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg)); nfg->nfgen_family = AF_UNSPEC; nfg->version = NFNETLINK_V0; nfg->res_id = htons(queue_num); return nlh;}#处理后返回给netfilter对数据包的处理static intnfq_send_verdict(int queue_num, uint32_t id){ char buf[MNL_SOCKET_BUFFER_SIZE]; struct nlmsghdr *nlh; int ret; nlh = nfq_hdr_put(buf, NFQNL_MSG_VERDICT, queue_num); nfq_nlmsg_verdict_put(nlh, id, NF_ACCEPT); if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { perror("mnl_socket_send"); exit(EXIT_FAILURE); } return ret;}static int queue_cb(const struct nlmsghdr *nlh, void *data){ struct nfqnl_msg_packet_hdr *ph = NULL; struct nlattr *attr[NFQA_MAX+1]; uint32_t id = 0; struct nfgenmsg *nfg; if (nfq_nlmsg_parse(nlh, attr) < 0) { perror("problems parsing"); return MNL_CB_ERROR; } nfg = mnl_nlmsg_get_payload(nlh); ph = (struct nfqnl_msg_packet_hdr *) mnl_attr_get_payload(attr[NFQA_PACKET_HDR]); if (ph == NULL) { perror("problems retrieving metaheader"); return MNL_CB_ERROR; } id = ntohl(ph->packet_id); printf("packet received (id=%u hw=0x%04x hook=%u)\n", id, ntohs(ph->hw_protocol), ph->hook); nfq_send_verdict(ntohs(nfg->res_id), id); return MNL_CB_OK;}int main(int argc, char *argv[]){ char buf[MNL_SOCKET_BUFFER_SIZE]; struct nlmsghdr *nlh; int ret; unsigned int portid, queue_num; #这里的queue_num是从参数里读进来的,在iptables命令里可以设置 if (argc != 2) { printf("Usage: %s [queue_num]\n", argv[0]); exit(EXIT_FAILURE); } queue_num = atoi(argv[1]); nl = mnl_socket_open(NETLINK_NETFILTER); if (nl == NULL) { perror("mnl_socket_open"); exit(EXIT_FAILURE); } if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) { perror("mnl_socket_bind"); exit(EXIT_FAILURE); } portid = mnl_socket_get_portid(nl); nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0); nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_UNBIND); if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { perror("mnl_socket_send"); exit(EXIT_FAILURE); } nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0); nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_BIND); if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { perror("mnl_socket_send"); exit(EXIT_FAILURE); } nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num); nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_BIND); if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { perror("mnl_socket_send"); exit(EXIT_FAILURE); } nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num); nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff); if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { perror("mnl_socket_send"); exit(EXIT_FAILURE); } ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); if (ret == -1) { perror("mnl_socket_recvfrom"); exit(EXIT_FAILURE); } while (ret > 0) { ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, NULL); if (ret < 0){ perror("mnl_cb_run"); exit(EXIT_FAILURE); } ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); if (ret == -1) { perror("mnl_socket_recvfrom"); exit(EXIT_FAILURE); } } mnl_socket_close(nl); return 0;}
在该文件夹内运行
make nf-queue
得到 nf-queue
另外,还有一个示例代码在“libnetfilter_queue-1.0.2/utils/nfqnl_test.c”,这里不细谈,同样make之后可以测试。
3.2 设置iptables
iptables -A OUTPUT -j NFQUEUE --queue-num 111
这里把发出的数据包都转到queue-num为111的用户态程序。
3.3 运行 nf-queue
./nf-queue 111
得到
....packet received (id=476 hw=0x0800 hook=3)packet received (id=477 hw=0x0800 hook=3)packet received (id=478 hw=0x0800 hook=3)packet received (id=479 hw=0x0800 hook=3)packet received (id=480 hw=0x0800 hook=3)packet received (id=481 hw=0x0800 hook=3)packet received (id=482 hw=0x0800 hook=3)packet received (id=483 hw=0x0800 hook=3)packet received (id=484 hw=0x0800 hook=3)
证明用户态的程序已经收到了数据包。
4. 性能相关
关于netfilter_queue的性能问题,http://www.netfilter.org/projects/libnetfilter_queue/doxygen/index.html 里提到了几个可以注意的点:
To improve your libnetfilter_queue application in terms of performance, you may consider the following tweaks:
increase the default socket buffer size by means of nfnl_rcvbufsiz().
set nice value of your process to -20 (maximum priority).
set the CPU affinity of your process to a spare core that is not used to handle NIC interruptions.
set NETLINK_NO_ENOBUFS socket option to avoid receiving ENOBUFS errors (requires Linux kernel >= 2.6.30).
see –queue-balance option in NFQUEUE target for multi-threaded apps (it requires Linux kernel >= 2.6.31).
- netfilter_queue
- 用netfilter_queue在用户态实现NAT
- 在ubuntu上做netfilter_queue开发
- 在centos6.3上编译netfilter_queue的configure问题及其解决方法
- 用netfilter_queue 在用户态修改网络数据包的例子程序
- 用netfilter_queue 在用户态修改网络数据包的例子程序
- 利用javascript计算n阶矩阵
- 在Linux服务器下修改mysql编码
- Spring Boot RabbitMQ 入门(三)之 Fanout交换器
- map 用法详解(转)
- Android---内存泄漏
- netfilter_queue
- 1-Wire总线-DS18B20及其驱动程序编写
- STM32F103程序设计-2-使用STLINK下载程序的两种方法
- Android Sqlite 漏洞
- sqlite3.3.5移植-arm-hisiv200-linux
- 对于个人计算机、网关、DNS服务器的理解(实例)
- PAT-B 1004. 成绩排名 (20)
- Xamarin.Forms特殊的视图BoxView
- 常见正则表达式用例