getipaddress.cpp

文件使用socket方法获取设备的ip地址

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <linux/sockios.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <asm/types.h>
#include <netinet/ether.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#define BUFSIZE 8192


struct route_info{
 in_addr dstAddr;
 in_addr srcAddr;
 in_addr gateWay;
 char ifName[IF_NAMESIZE];
};
int readNlSock(int sockFd, char *bufPtr, int seqNum, int pId)
{
 struct nlmsghdr *nlHdr;
 int readLen = 0, msgLen = 0;
 do
 {
  /* Recieve response from the kernel */
  if((readLen = recv(sockFd, bufPtr, BUFSIZE - msgLen, 0)) < 0){
   perror("SOCK READ: ");
   return -1;
  }
 
  nlHdr = (struct nlmsghdr *)bufPtr;
  /* Check if the header is valid */
  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;
}

/* For parsing the route info returned */
void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo,char *gateway)
{
 struct rtmsg *rtMsg;
 struct rtattr *rtAttr;
 int rtLen;
 char *tempBuf = NULL;
 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 = *(in_addr *)RTA_DATA(rtAttr);
   break;
  case RTA_PREFSRC:
 	rtInfo->srcAddr = *(in_addr *)RTA_DATA(rtAttr);
   break;
  case RTA_DST:
	rtInfo->dstAddr = *(in_addr *)RTA_DATA(rtAttr);
   break;
  }
 }
 if (strstr((char *)inet_ntoa(rtInfo->dstAddr), "0.0.0.0"))
  sprintf(gateway, (char *)inet_ntoa(rtInfo->gateWay));
 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;
 char buff[1024]; 
 /* Create Socket */
 if((sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
 perror("Socket Creation: ");
 
 /* 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));
 // ADDED BY BOB
 /* THIS IS THE NETTSTAT -RL code I commented out the printing here and in parse routes */
 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;
}

int main(void)
{
	int s;
	struct ifconf conf;
	struct ifreq *ifr;
	char buff[BUFSIZ];
	char ipaddress[20]={""};
	char netmode[20]={""};
	char netmask[20]={""};
	int num;
	int i;
	s = socket(PF_INET, SOCK_DGRAM, 0);
	conf.ifc_len = BUFSIZ;
	conf.ifc_buf = buff;
	if(ioctl(s, SIOCGIFCONF, &conf) == -1)
	{
		printf("Couldn't get ip settings");
		return 0;
	}	
	num = conf.ifc_len / sizeof(struct ifreq);
	ifr = conf.ifc_req;	
	for(i=0;i < num;i++)
	{
		struct sockaddr_in *sin = (struct sockaddr_in *)(&ifr->ifr_addr);
		if(ioctl(s, SIOCGIFFLAGS, ifr) == -1)
		{
			printf("Can't get ipaddress!\n");	
			return 0;			
		}	
		if(((ifr->ifr_flags & IFF_LOOPBACK) == 0) && (ifr->ifr_flags & IFF_UP)&& (strcmp(ifr->ifr_name,"eth0") == 0))
		{
			strcpy(ipaddress,inet_ntoa(sin->sin_addr));
		}		
		ifr++;
	}
	printf("ipaddress = %s\n",ipaddress);	
	//获取子网掩码
	struct sockaddr_in *addr = (struct sockaddr_in *)(&ifr->ifr_addr);
	strcpy(ifr->ifr_name,"eth0");
	if(ioctl(s,SIOCGIFNETMASK,ifr) == -1)
	{
		printf("Can't get netmask!\n");
		return 0;
	}
	strcpy(netmask,inet_ntoa(addr->sin_addr));
	printf("netmask = %s\n",netmask);
	//获取默认网关
	char gateway[255]={0};
	get_gateway(gateway);
	printf("Gateway:%s\n", gateway);
	return 1;
}