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获取内核路由62616964757a686964616fe58685e5aeb931333335343937表以及操作内核路由表有几种方法：读proc 或者用ioctl(sock_fd, SIOCADDRT, &rt)，这里的第二个参数是设置路由表，读也有相应的参数，还有第三种方法就是用netlink接口对内核路由表进行读取、增加、删除操作

如linaxing(牛牛)所说,以前是用IOCTL,不过那个读出的和netlink的有点差别,是信息量有差别.具体我也说不清楚,可查看相关maillist,那个牛人也就说了一句话

下面给出偶自己读内核路由表的一个程序,仿照zebra的用法

不过,最后读出的内容有点问题,好像还得转换一下,实在写不动了,欢迎批评!

#include

#include

#include

#include

#include

#include

//#include

//#include

#include

#ifdef SEQ

struct rtnl_handle

{

unsigned int seq;

}

#endif

static void parse_rtattr(struct rtattr **tb, int max,

struct rtattr *rta, int len)

{

while(RTA_OK(rta, len))

{

if(rta-> rta_type <= max)

tb[rta-> rta_type] = rta;

rta = RTA_NEXT(rta, len);

}

}

int routeprint( struct sockaddr_nl *snl, struct nlmsghdr *h2)

{

#if 1

struct rtmsg *rtm;

struct rtattr *tb[RTA_MAX + 1];

int len;

int index;

int table;

void* dest;

void* gate;

char dest2[100];

rtm = NLMSG_DATA(h2);//get the data portion of "h2 "

index = 0;

dest = NULL;

gate = NULL;

table = rtm-> rtm_table;

len = h2-> nlmsg_len - NLMSG_LENGTH(sizeof(struct rtmsg));

memset(tb, 0, sizeof tb);

parse_rtattr(tb, RTA_MAX, RTM_RTA(rtm), len);

if(tb[RTA_OIF])

index = *(int *)RTA_DATA(tb[RTA_OIF]);

if(tb[RTA_DST]){

dest = RTA_DATA(tb[RTA_DST]);

// printf( "debug dest\n ");

}

else dest = 0;

#if 1

if(tb[RTA_METRICS]){

gate = RTA_DATA(tb[RTA_METRICS]);

}

#else

if(tb[RTA_GATEWAY]){

gate = RTA_DATA(tb[RTA_GATEWAY]);

//iprintf( "debug gate\n ");

}

#endif

printf( "family:%d\t ",rtm-> rtm_family);

printf( "index: %d\t ", index);

// memcpy(dest2, dest, 4);

printf( "dest: %d\t ", dest);

// printf( "dest: %c\t ", dest2[1]);

// printf( "dest: %c\t ", dest2[2]);

// printf( "dest: %c\t ", dest2[3]);

printf( "gate: %d\n ", gate);

#endif

return 1;

}

#ifdef SEQ

int getroute(int sockfd,struct rtnl_handle *rtnl)

#else

int getroute(int sockfd)

#endif

{

int i;

int status, sendsize;

unsigned char buf[8192];

struct iovec iov = {(void*)buf, sizeof(buf)};

struct sockaddr_nl nladdr;

struct nlmsghdr *h;

struct

{

struct nlmsghdr nlh;

struct rtgenmsg g;

}req;

struct msghdr msg = { (void*)&nladdr, sizeof(nladdr),

&iov, 1, NULL, 0, 0};

nladdr.nl_family = AF_NETLINK;

req.nlh.nlmsg_len = sizeof(req);

req.nlh.nlmsg_type = RTM_GETROUTE; //增加或删除内核路由表相应改成RTM_ADDROUTE和RTM_DELROUTE

req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;

req.nlh.nlmsg_pid = 0;

#ifdef SEQ

req.nlh.nlmsg_seq = ++rtnl-> seq;//may be 0?

#else

//int i;

//if (i > 4096) i = 1;

req.nlh.nlmsg_seq = 1;

#endif

req.g.rtgen_family = AF_INET;

printf( "sockfd: %d\n ", sockfd);

if((sendsize=sendto(sockfd, (void*)&req, sizeof(req), 0,

(struct sockaddr*)&nladdr, sizeof(nladdr))) < 0){

perror( "sendto ");

return -1;

}

printf( "sendsize= %d\n ",sendsize);

if((status=recvmsg(sockfd, &msg, 0)) < 0){

perror( "recvmsg ");

return -1;

}

printf( "status= %d\n ",status);

#if 1 //segmentation fault

for(h = (struct nlmsghdr*)buf; NLMSG_OK(h, status);

h = NLMSG_NEXT(h, status))

{

if(h-> nlmsg_type == NLMSG_DONE)

{

printf( "finish reading\n ");

return 1;

}

if(h-> nlmsg_type == NLMSG_ERROR)

{

printf( "h:nlmsg ERROR ");

return 1;

}

routeprint(&nladdr, h);

}

#endif

// printf( "Can 't convert 'h '\n ");

// routeprint(h);

return 1;

}

int main()

{

int sockfd;

#ifdef SEQ

struct rtnl_handle rth;

#endif

struct sockaddr_nl nladdr;

if((sockfd = socket(AF_NETLINK, SOCK_RAW,

NETLINK_ROUTE)) <0){

perror( "netlink socket ");

return -1;

}

nladdr.nl_family = AF_NETLINK;

nladdr.nl_pad = 0;

nladdr.nl_pid = 0;

nladdr.nl_groups = RTMGRP_LINK|RTMGRP_IPV4_ROUTE|

RTMGRP_IPV4_IFADDR;

if(bind(sockfd, (struct sockaddr*)&nladdr,

sizeof(nladdr)) < 0){

perror( "bind ");

close(sockfd);

return -1;

}

#ifdef SEQ

if(getroute(sockfd, &rth) < 0){

#else

if(getroute(sockfd) < 0){

#endif

perror( "can 't get route\n ");

return -1;

}

return 1;

}

本回答由电脑网络分类达人 郭强推荐

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