从网络链路消息中提取当前路径,code附 [英] Extract current route from netlink message, code attached
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问题描述
我想,以监测网络连接套接字路线的变化,但我应该怎么获取更新的路由地址?
code:
的#include< SYS / socket.h中>
#包括LT&;&stdlib.h中GT;
#包括LT&;&stdio.h中GT;
#包括LT&;&string.h中GT;
#包括LT&; Linux的/ netlink.h>
#包括LT&; Linux的/ rtnetlink.h>
#定义ERR_RET(X)做{PERROR(X);返回EXIT_FAILURE; }而(0);无效循环(INT袜子)
{
结构sockaddr_nl nladdr;
结构指向msghdr味精;
结构iovec的IOV [2];
结构nlmsghdr NLH;
字符缓冲区[65536] IOV [0] = .iov_base(无效*)及北大屿山医院;
IOV [0] = .iov_len的sizeof(NLH);
IOV [1] .iov_base =(无效*)缓冲区;
IOV [1] .iov_len = sizeof的(缓冲器); msg.msg_name =(无效*)及(nladdr);
msg.msg_namelen = sizeof的(nladdr);
msg.msg_iov = IOV;
msg.msg_iovlen = sizeof的(IOV)/的sizeof(结构iovec的); 如果(recvmsg(袜子,和放大器;味精,0))
{
如果(nlh.nlmsg_type == RTM_NEWROUTE)
{
的printf(新航线邮件\\ n);
}
否则,如果(nlh.nlmsg_type == RTM_DELROUTE)
{
的printf(德尔航线邮件\\ n);
}
}
}INT主(INT ARGC,CHAR *的argv [])
{
INT袜子= -1;
结构sockaddr_nl地址;
bzero(安培;地址,的sizeof(地址)); 如果((袜子=插座(AF_NETLINK,SOCK_RAW,NETLINK_ROUTE))小于0)
ERR_RET(插座); addr.nl_family = AF_NETLINK;
addr.nl_groups = RTMGRP_IPV4_ROUTE; 如果(绑定(袜子,(结构sockaddr *)及地址,的sizeof(地址))小于0)
ERR_RET(绑定); 而(1)
环(袜子);
返回0;
}
解决方案
我编辑你的code和增加两个结构(),路由表变化(code被注释掉)时,为了获得所需的信息。
/ *这项计划的目的是监控路由
*表更改
* /#包括LT&; SYS / socket.h中>
#包括LT&;&stdlib.h中GT;
#包括LT&;&stdio.h中GT;
#包括LT&;&string.h中GT;
#包括LT&; Linux的/ netlink.h>
#包括LT&; Linux的/ rtnetlink.h>
#包括LT&; ARPA / inet.h>
#包括LT&;&unistd.h中GT;#定义ERR_RET(X)做{PERROR(X);返回EXIT_FAILURE; }而(0);
的#define BUFFER_SIZE 4095INT回路(INT袜子,结构sockaddr_nl *地址)
{
INT received_bytes = 0;
结构nlmsghdr * NLH;
焦炭目的地地址[32];
焦炭gateway_address [32];
结构rtmsg * route_entry; / *这个结构重新present的路由条目\\
在路由表中* /
结构rtattr * route_attribute; / *这个结构包含路径\\
属性(路由类型)* /
INT route_attribute_len = 0;
字符缓冲区[BUFFER_SIZE]; bzero(目的地地址,的sizeof(目的地地址));
bzero(gateway_address,sizeof的(gateway_address));
bzero(缓冲液,的sizeof(缓冲液)); / *接收的网络连接套接字数据* /
而(1)
{
received_bytes =的recv(袜子,缓冲器,的sizeof(缓冲液),0);
如果(received_bytes℃,)
ERR_RET(RECV);
/ *投接收缓冲区* /
NLH =(结构nlmsghdr *)缓冲区;
/ *如果我们收到的所有数据--->打破* /
如果(nlh-> nlmsg_type == NLMSG_DONE)
打破;
/ *我们是路由信息只是intrested * /
如果(addr-> nl_groups == RTMGRP_IPV4_ROUTE)
打破;
} / *阅读的网络连接套接字数据* /
/ *通过所有条目循环* /
/ *有关的一些功能更多的信息:
* http://www.kernel.org/doc/man-pages/online/pages/man3/netlink.3.html
* http://www.kernel.org/doc/man-pages/online/pages/man7/rtnetlink.7.html
* / 对于(; NLMSG_OK(北大屿山医院,received_bytes); \\
NLH = NLMSG_NEXT(北大屿山医院,received_bytes))
{
/ *获取路线数据* /
route_entry =(结构rtmsg *)NLMSG_DATA(NLH); / *我们是在主路由表只是intrested * /
如果(route_entry->!rtm_table = RT_TABLE_MAIN)
继续; / *获取route_entry属性* /
route_attribute =(结构rtattr *)RTM_RTA(route_entry); / *获取路线atttibutes len个* /
route_attribute_len = RTM_PAYLOAD(NLH);
/ *遍历所有属性* /
为(; RTA_OK(route_attribute,route_attribute_len); \\
route_attribute = RTA_NEXT(route_attribute,route_attribute_len))
{
/ *获取目的地址* /
如果(route_attribute-> rta_type == RTA_DST)
{
inet_ntop(AF_INET,RTA_DATA(route_attribute),\\
目的地地址,sizeof的(目的地地址));
}
/ *获取网关(下一跳)* /
如果(route_attribute-> rta_type == RTA_GATEWAY)
{
inet_ntop(AF_INET,RTA_DATA(route_attribute),\\
gateway_address,sizeof的(gateway_address));
}
} / *现在,我们可以转储路由属性* /
如果(nlh-> nlmsg_type == RTM_DELROUTE)
fprintf中(标准输出,删除路线的目的地 - >%s和网关%S \\ n,\\
目的地地址,gateway_address);
如果(nlh-> nlmsg_type == RTM_NEWROUTE)
的printf(增加路线的目的地 - >%s和网关%S \\ n,\\
目的地地址,gateway_address);
} 返回0;
}INT主(INT ARGC,字符** argv的)
{
INT袜子= -1;
结构sockaddr_nl地址; / *归零地址* /
bzero(安培;地址,的sizeof(地址)); 如果((袜子=插座(AF_NETLINK,SOCK_RAW,NETLINK_ROUTE))小于0)
ERR_RET(插座); addr.nl_family = AF_NETLINK;
addr.nl_groups = RTMGRP_IPV4_ROUTE; 如果(绑定(袜子,(结构sockaddr *)及地址,的sizeof(地址))小于0)
ERR_RET(绑定); 而(1)
环(袜子,&安培;地址); / *关闭插座* /
关闭(袜子); 返回0;
}
您可以测试这样为例(如根路由添加到路由表中):
根@#UnixServer路由添加-host 10.113.0.0 GW bsdBox
根@#UnixServer德尔路线-host 10.113.0.0 GW bsdBox
在我的机器上我得到这样的输出:
TOC @ UnixServer:〜$ / route_monitor
添加路线的目的地 - > 10.113.0.0和网关192.168.1.1
删除路线的目的地 - > 10.113.0.0和网关192.168.1.1
^ C
I'm trying to monitor route changes with netlink socket, but how should I get the updated route address ?
Code:
#include <sys/socket.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#define ERR_RET(x) do { perror(x); return EXIT_FAILURE; } while (0);
void loop (int sock)
{
struct sockaddr_nl nladdr;
struct msghdr msg;
struct iovec iov[2];
struct nlmsghdr nlh;
char buffer[65536];
iov[0].iov_base = (void *)&nlh;
iov[0].iov_len = sizeof(nlh);
iov[1].iov_base = (void *)buffer;
iov[1].iov_len = sizeof(buffer);
msg.msg_name = (void *)&(nladdr);
msg.msg_namelen = sizeof(nladdr);
msg.msg_iov = iov;
msg.msg_iovlen = sizeof(iov)/sizeof(struct iovec);
if ( recvmsg (sock, &msg, 0) )
{
if ( nlh.nlmsg_type == RTM_NEWROUTE )
{
printf ("New route message\n");
}
else if ( nlh.nlmsg_type == RTM_DELROUTE )
{
printf ("Del route message\n");
}
}
}
int main(int argc, char *argv[])
{
int sock = -1;
struct sockaddr_nl addr;
bzero (&addr, sizeof(addr));
if ( (sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE) ) < 0 )
ERR_RET("socket");
addr.nl_family = AF_NETLINK;
addr.nl_groups = RTMGRP_IPV4_ROUTE;
if (bind(sock,(struct sockaddr *)&addr,sizeof(addr))<0)
ERR_RET("bind");
while (1)
loop (sock);
return 0;
}
解决方案
I edited your code and add two structs (), to get the needed information when routing table change (the code is commented).
/* The purpose of this program is to monitor routing
* table changes
*/
#include <sys/socket.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <arpa/inet.h>
#include <unistd.h>
#define ERR_RET(x) do { perror(x); return EXIT_FAILURE; } while (0);
#define BUFFER_SIZE 4095
int loop (int sock, struct sockaddr_nl *addr)
{
int received_bytes = 0;
struct nlmsghdr *nlh;
char destination_address[32];
char gateway_address[32];
struct rtmsg *route_entry; /* This struct represent a route entry \
in the routing table */
struct rtattr *route_attribute; /* This struct contain route \
attributes (route type) */
int route_attribute_len = 0;
char buffer[BUFFER_SIZE];
bzero(destination_address, sizeof(destination_address));
bzero(gateway_address, sizeof(gateway_address));
bzero(buffer, sizeof(buffer));
/* Receiving netlink socket data */
while (1)
{
received_bytes = recv(sock, buffer, sizeof(buffer), 0);
if (received_bytes < 0)
ERR_RET("recv");
/* cast the received buffer */
nlh = (struct nlmsghdr *) buffer;
/* If we received all data ---> break */
if (nlh->nlmsg_type == NLMSG_DONE)
break;
/* We are just intrested in Routing information */
if (addr->nl_groups == RTMGRP_IPV4_ROUTE)
break;
}
/* Reading netlink socket data */
/* Loop through all entries */
/* For more informations on some functions :
* http://www.kernel.org/doc/man-pages/online/pages/man3/netlink.3.html
* http://www.kernel.org/doc/man-pages/online/pages/man7/rtnetlink.7.html
*/
for ( ; NLMSG_OK(nlh, received_bytes); \
nlh = NLMSG_NEXT(nlh, received_bytes))
{
/* Get the route data */
route_entry = (struct rtmsg *) NLMSG_DATA(nlh);
/* We are just intrested in main routing table */
if (route_entry->rtm_table != RT_TABLE_MAIN)
continue;
/* Get attributes of route_entry */
route_attribute = (struct rtattr *) RTM_RTA(route_entry);
/* Get the route atttibutes len */
route_attribute_len = RTM_PAYLOAD(nlh);
/* Loop through all attributes */
for ( ; RTA_OK(route_attribute, route_attribute_len); \
route_attribute = RTA_NEXT(route_attribute, route_attribute_len))
{
/* Get the destination address */
if (route_attribute->rta_type == RTA_DST)
{
inet_ntop(AF_INET, RTA_DATA(route_attribute), \
destination_address, sizeof(destination_address));
}
/* Get the gateway (Next hop) */
if (route_attribute->rta_type == RTA_GATEWAY)
{
inet_ntop(AF_INET, RTA_DATA(route_attribute), \
gateway_address, sizeof(gateway_address));
}
}
/* Now we can dump the routing attributes */
if (nlh->nlmsg_type == RTM_DELROUTE)
fprintf(stdout, "Deleting route to destination --> %s and gateway %s\n", \
destination_address, gateway_address);
if (nlh->nlmsg_type == RTM_NEWROUTE)
printf("Adding route to destination --> %s and gateway %s\n", \
destination_address, gateway_address);
}
return 0;
}
int main(int argc, char **argv)
{
int sock = -1;
struct sockaddr_nl addr;
/* Zeroing addr */
bzero (&addr, sizeof(addr));
if ((sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
ERR_RET("socket");
addr.nl_family = AF_NETLINK;
addr.nl_groups = RTMGRP_IPV4_ROUTE;
if (bind(sock,(struct sockaddr *)&addr,sizeof(addr)) < 0)
ERR_RET("bind");
while (1)
loop (sock, &addr);
/* Close socket */
close(sock);
return 0;
}
You can test like this for example (as root to add routes to the routing table):
root@UnixServer# route add -host 10.113.0.0 gw bsdBox
root@UnixServer# route del -host 10.113.0.0 gw bsdBox
In my machine i got this output:
toc@UnixServer:~$./route_monitor
Adding route to destination --> 10.113.0.0 and gateway 192.168.1.1
Deleting route to destination --> 10.113.0.0 and gateway 192.168.1.1
^C
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