linux系统下获取IP，MAC，子网掩码，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;
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,> parseRoutes(nlMsg, rtInfo,gateway);
}
free(rtInfo);
close(sock);
return 0;
}
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