添加对应头文件
#include<stdio.h>
#include <cstdlib>
#include<string.h>
#include<unistd.h>
#include <fstream>
#include<iostream>
#include <net/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <errno.h>
#include <linux/rtnetlink.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/utsname.h>
#include <limits.h>
#include <ctype.h>
#include <linux/sockios.h>
获取IP和子网掩码
int getLocalInfo(char IP[],char Mask[])
{
int fd;
int interfaceNum = 0;
struct ifreq buf[16];
struct ifconf ifc;
struct ifreq ifrcopy;
char mac[16] = {0};
char ip[32] = {0};
char broadAddr[32] = {0};
char subnetMask[32] = {0};
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
perror("socket");
close(fd);
return -1;
}
ifc.ifc_len = sizeof(buf);
ifc.ifc_buf = (caddr_t)buf;
if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc))
{
interfaceNum = ifc.ifc_len / sizeof(struct ifreq);
printf("interface num = %d\n", interfaceNum);
while (interfaceNum-- > 0)
{
printf("\ndevice name: %s\n", buf[interfaceNum].ifr_name);
//ignore the interface that not up or not runing
ifrcopy = buf[interfaceNum];
if (ioctl(fd, SIOCGIFFLAGS, &ifrcopy))
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
//get the mac of this interface
if (!ioctl(fd, SIOCGIFHWADDR, (char *)(&buf[interfaceNum])))
{
memset(mac, 0, sizeof(mac));
snprintf(mac, sizeof(mac), "%02x%02x%02x%02x%02x%02x",
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[0],
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[1],
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[2],
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[3],
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[4],
(unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[5]);
printf("device mac: %s\n", mac);
}
else
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
//get the IP of this interface
if (!ioctl(fd, SIOCGIFADDR, (char *)&buf[interfaceNum]))
{
snprintf(ip, sizeof(ip), "%s",
(char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_addr))->sin_addr));
printf("device ip: %s\n", ip);
}
else
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
//get the broad address of this interface
if (!ioctl(fd, SIOCGIFBRDADDR, &buf[interfaceNum]))
{
snprintf(broadAddr, sizeof(broadAddr), "%s",
(char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_broadaddr))->sin_addr));
printf("device broadAddr: %s\n", broadAddr);
}
else
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
//get the subnet mask of this interface
if (!ioctl(fd, SIOCGIFNETMASK, &buf[interfaceNum]))
{
snprintf(subnetMask, sizeof(subnetMask), "%s",
(char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_netmask))->sin_addr));
printf("device subnetMask: %s\n", subnetMask);
}
else
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
}
}
else
{
printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__);
close(fd);
return -1;
}
strcpy(IP,ip);
//strcpy(broad,broadAddr);
strcpy(Mask,subnetMask);
close(fd);
return 0;
}
获取网关
int readNlSock(int sockFd, char *bufPtr, int seqNum, int pId)
{
struct nlmsghdr *nlHdr;
int readLen = 0, msgLen = 0;
do{
if((readLen = recv(sockFd, bufPtr, BUFSIZE - msgLen, 0)) < 0)
{
perror("SOCK READ: ");
return -1;
}
nlHdr = (struct nlmsghdr *)bufPtr;
if((NLMSG_OK(nlHdr, readLen) == 0) || (nlHdr->nlmsg_type == NLMSG_ERROR))
{
perror("Error in recieved packet");
return -1;
}
if(nlHdr->nlmsg_type == NLMSG_DONE)
{
break;
}
else
{
bufPtr += readLen;
msgLen += readLen;
}
if((nlHdr->nlmsg_flags & NLM_F_MULTI) == 0)
{
break;
}
} while((nlHdr->nlmsg_seq != seqNum) || (nlHdr->nlmsg_pid != pId));
return msgLen;
}
void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo,char gateway[])
{
struct rtmsg *rtMsg;
struct rtattr *rtAttr;
int rtLen;
char *tempBuf = NULL;
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;
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;
}
}
dst.s_addr = rtInfo->dstAddr;
if (strstr((char *)inet_ntoa(dst), "0.0.0.0"))
{
printf("oif:%s",rtInfo->ifName);
gate.s_addr = rtInfo->gateWay;
sprintf(gateway, (char *)inet_ntoa(gate));
printf("%s\n",gateway);
gate.s_addr = rtInfo->srcAddr;
printf("src:%s\n",(char *)inet_ntoa(gate));
gate.s_addr = rtInfo->dstAddr;
printf("dst:%s\n",(char *)inet_ntoa(gate));
}
free(tempBuf);
return;
}
int get_gateway(char gateway[])
{
struct nlmsghdr *nlMsg;
struct rtmsg *rtMsg;
struct route_info *rtInfo;
char msgBuf[BUFSIZE];
int sock, len, msgSeq = 0;
if((sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
{
perror("Socket Creation: ");
return -1;
}
memset(msgBuf, 0, BUFSIZE);
nlMsg = (struct nlmsghdr *)msgBuf;
rtMsg = (struct rtmsg *)NLMSG_DATA(nlMsg);
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.
if(send(sock, nlMsg, nlMsg->nlmsg_len, 0) < 0){
printf("Write To Socket Failed…\n");
return -1;
}
if((len = readNlSock(sock, msgBuf, msgSeq, getpid())) < 0) {
printf("Read From Socket Failed…\n");
return -1;
}
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;
}
