一、取得本机ip及掩码

/********************************************************************

* 函数名： get_host_info

* 参数名： local_ip(out)    ip

*         local_mask(out)  mask

* 返回值： 0                成功

*         -1              失败

* 功  能：获取本地机的ip及掩码

********************************************************************/

int get_host_info(string &local_ip, string &local_mask)

{

struct sockaddr_in *my_ip;

struct sockaddr_in *addr;

struct sockaddr_in myip;

my_ip = &myip;

struct ifreq ifr;

int sock;

if((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

return -1;

}

strcpy(ifr.ifr_name, "eth0");

//取本机IP地址

if(ioctl(sock, SIOCGIFADDR, &ifr) < 0)

{

return -1;

}

my_ip->sin_addr = ((struct sockaddr_in *)(&ifr.ifr_addr))->sin_addr;

local_ip = inet_ntoa(my_ip->sin_addr);

//取本机掩码

if( ioctl( sock, SIOCGIFNETMASK, &ifr) == -1 ){

perror("[-] ioctl");

return -1;

}

addr = (struct sockaddr_in *) & (ifr.ifr_addr);

local_mask = inet_ntoa( addr->sin_addr);

close(sock);

return 0;

}

二、取得本机网关

从网上找的，其中的错误已修改。

#define BUFSIZE 8192

struct route_info{

u_int dstAddr;

u_int srcAddr;

u_int gateWay;

char ifName[IF_NAMESIZE];

};

int readNlSock(int sockFd, char *bufPtr, int seqNum, int pId)

{

struct nlmsghdr *nlHdr;

int readLen = 0, msgLen = 0;

do{

//收到内核的应答

if((readLen = recv(sockFd, bufPtr, BUFSIZE - msgLen, 0)) < 0)

{

perror("SOCK READ: ");

return -1;

}

nlHdr = (struct nlmsghdr *)bufPtr;

//检查header是否有效

if((NLMSG_OK(nlHdr, readLen) == 0) || (nlHdr->nlmsg_type == NLMSG_ERROR))

{

perror("Error in recieved packet");

return -1;

}

/* Check if the its the last message */

if(nlHdr->nlmsg_type == NLMSG_DONE)

{

break;

}

else

{

/* Else move the pointer to buffer appropriately */

bufPtr += readLen;

msgLen += readLen;

}

/* Check if its a multi part message */

if((nlHdr->nlmsg_flags & NLM_F_MULTI) == 0)

{

/* return if its not */

break;

}

} while((nlHdr->nlmsg_seq != seqNum) || (nlHdr->nlmsg_pid != pId));

return msgLen;

}

//分析返回的路由信息

void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo,char *gateway)

{

struct rtmsg *rtMsg;

struct rtattr *rtAttr;

int rtLen;

char *tempBuf = NULL;

//2007-12-10

struct in_addr dst;

struct in_addr gate;

tempBuf = (char *)malloc(100);

rtMsg = (struct rtmsg *)NLMSG_DATA(nlHdr);

// If the route is not for AF_INET or does not belong to main routing table

//then return.

if((rtMsg->rtm_family != AF_INET) || (rtMsg->rtm_table != RT_TABLE_MAIN))

return;

/* get the rtattr field */

rtAttr = (struct rtattr *)RTM_RTA(rtMsg);

rtLen = RTM_PAYLOAD(nlHdr);

for(;RTA_OK(rtAttr,rtLen);rtAttr = RTA_NEXT(rtAttr,rtLen)){

switch(rtAttr->rta_type) {

case RTA_OIF:

if_indextoname(*(int *)RTA_DATA(rtAttr), rtInfo->ifName);

break;

case RTA_GATEWAY:

rtInfo->gateWay = *(u_int *)RTA_DATA(rtAttr);

break;

case RTA_PREFSRC:

rtInfo->srcAddr = *(u_int *)RTA_DATA(rtAttr);

break;

case RTA_DST:

rtInfo->dstAddr = *(u_int *)RTA_DATA(rtAttr);

break;

}

}

//2007-12-10

dst.s_addr = rtInfo->dstAddr;

if (strstr((char *)inet_ntoa(dst), "0.0.0.0"))

{

gate.s_addr = rtInfo->gateWay;

sprintf(gateway, (char *)inet_ntoa(gate));

}

free(tempBuf);

return;

}

/********************************************************************

* 函数名： get_gateway

* 参数名： gateway(out)   网关

* 返回值： 0            成功

*          -1             失败

* 功  能：获取本地机的网关

********************************************************************/int get_gateway(char *gateway)

{

struct nlmsghdr *nlMsg;

struct rtmsg *rtMsg;

struct route_info *rtInfo;

char msgBuf[BUFSIZE];

int sock, len, msgSeq = 0;

//创建 Socket

if((sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)

{

perror("Socket Creation: ");

return -1;

}

/* Initialize the buffer */

memset(msgBuf, 0, BUFSIZE);

/* point the header and the msg structure pointers into the buffer */

nlMsg = (struct nlmsghdr *)msgBuf;

rtMsg = (struct rtmsg *)NLMSG_DATA(nlMsg);

/* Fill in the nlmsg header*/

nlMsg->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)); // Length of message.

nlMsg->nlmsg_type = RTM_GETROUTE; // Get the routes from kernel routing table .

nlMsg->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST; // The message is a request for dump.

nlMsg->nlmsg_seq = msgSeq++; // Sequence of the message packet.

nlMsg->nlmsg_pid = getpid(); // PID of process sending the request.

/* Send the request */

if(send(sock, nlMsg, nlMsg->nlmsg_len, 0) < 0){

printf("Write To Socket Failed.../n");

return -1;

}

/* Read the response */

if((len = readNlSock(sock, msgBuf, msgSeq, getpid())) < 0) {

printf("Read From Socket Failed.../n");

return -1;

}

/* Parse and print the response */

rtInfo = (struct route_info *)malloc(sizeof(struct route_info));

for(;NLMSG_OK(nlMsg,len);nlMsg = NLMSG_NEXT(nlMsg,len)){

memset(rtInfo, 0, sizeof(struct route_info));

parseRoutes(nlMsg, rtInfo,gateway);

}

free(rtInfo);

close(sock);

return 0;

}

把这些头文件都包含进来吧，我也没具体看哪些没用，反正都加上没错误：

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

如果用到string类型，再加上：

using namespace std;

以上函数都是经过编译运行通过的。

把这些整理在这里一是备忘，二是给大家方便！