嵌入式 hi3518平台获取网关

</pre><pre code_snippet_id="495447" snippet_file_name="blog_20141024_1_7065081" name="code" class="html">/********************************** (C) COPYRIGHT *******************************/

 * File Name          : get_gw.c   * Author             : skdkjzz   * Date               : 2014/08/07   * Description        : linux下获取网卡信息   *********************************************************************************/  #include <stdio.h>#include <stdlib.h>#include <string.h>#include <asm/types.h>#include <netinet/ether.h>#include <netinet/in.h>#include <net/if.h>#include <stdio.h>#include <sys/socket.h>#include <sys/ioctl.h>#include <linux/netlink.h>#include <linux/rtnetlink.h>#include <sys/types.h>#define JSOEPH_NET_RMSG_BUFSIZE 8192typedef struct route_info{u_int dstAddr;u_int srcAddr;u_int gateWay;u_int genmask;char ifName[IF_NAMESIZE];}JOSEPH_ROUTE_INFO;#ifdef JOSEPH_CAT_ENUM/* Routing message attributes */enum rtattr_type_t {RTA_UNSPEC,RTA_DST,RTA_SRC,RTA_IIF,RTA_OIF,RTA_GATEWAY,RTA_PRIORITY,RTA_PREFSRC,RTA_METRICS,RTA_MULTIPATH,RTA_PROTOINFO, /* no longer used */RTA_FLOW,RTA_CACHEINFO,RTA_SESSION, /* no longer used */RTA_MP_ALGO, /* no longer used */RTA_TABLE,RTA_MARK,__RTA_MAX};#endifint Joseph_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, JSOEPH_NET_RMSG_BUFSIZE - msgLen, 0)) < 0){printf("SOCK READ Error !\n");return -1;}nlHdr = (struct nlmsghdr *)bufPtr;/* Check if the header is valid */if((NLMSG_OK(nlHdr, readLen) == 0) || (nlHdr->nlmsg_type == NLMSG_ERROR)){printf("Error in recieved packet !\n");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 printing the routes. */void Joseph_PrintRoute(struct route_info *rtInfo,char *if_name_in){char tempBuf[512];if(strcmp(rtInfo->ifName,if_name_in) == 0){/* Print Destination address */if(rtInfo->dstAddr != 0)strcpy(tempBuf, (char *)inet_ntoa(rtInfo->dstAddr));elsesprintf(tempBuf,"0.0.0.0\t");fprintf(stdout,"%s\t", tempBuf);/* Print Gateway address */if(rtInfo->gateWay != 0)strcpy(tempBuf, (char *)inet_ntoa(rtInfo->gateWay));elsesprintf(tempBuf,"0.0.0.0\t");fprintf(stdout,"%s\t", tempBuf);/* Print Interface Name*/fprintf(stdout,"%s\t", rtInfo->ifName);/* Print genmask address */if(rtInfo->genmask != 0)strcpy(tempBuf, (char *)inet_ntoa(rtInfo->genmask));elsesprintf(tempBuf,"0.0.0.0\t");fprintf(stdout,"%s\t", tempBuf);/* Print Source address */if(rtInfo->srcAddr != 0)strcpy(tempBuf, (char *)inet_ntoa(rtInfo->srcAddr));elsesprintf(tempBuf,"0.0.0.0\t");fprintf(stdout,"%s\n", tempBuf);}}/* For parsing the route info returned */int Joseph_ParseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo,char *gateway,char *if_name_in){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)){free(tempBuf);tempBuf = NULL;return -1;}/* 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;}}//printf("%s\n", (char *)inet_ntoa(rtInfo->dstAddr));//ADDED BY BOB - ALSO COMMENTED Joseph_PrintRouteif (strstr((char *)inet_ntoa(rtInfo->dstAddr), "0.0.0.0")){sprintf(gateway,"%s",(char *)inet_ntoa(rtInfo->gateWay));}Joseph_PrintRoute(rtInfo,if_name_in);free(tempBuf);tempBuf = NULL;return 0;}int Joseph_Get_Gateway(char *gateway,char *if_name){struct nlmsghdr *nlMsg;struct rtmsg *rtMsg;struct route_info *rtInfo;char msgBuf[JSOEPH_NET_RMSG_BUFSIZE];int sock, len, msgSeq = 0;char buff[1024];if(strlen(if_name) == 0 || gateway == NULL){return -1;}/* Create Socket */if((sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0){printf("Socket Creation Error !\n");return -1;}/* Initialize the buffer */memset(msgBuf, 0, JSOEPH_NET_RMSG_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");close(sock);return -1;}/* Read the response */if((len = Joseph_ReadNlSock(sock, msgBuf, msgSeq, getpid())) < 0) {printf("Read From Socket Failed...\n");close(sock);return -1;}/* Parse and print the response */rtInfo = (struct route_info *)malloc(sizeof(struct route_info));/* THIS IS THE NETTSTAT -RL code I commented out the printing here and in parse routes *///fprintf(stdout, "Destination\tGateway\tInterface\tSource\n");for( ; NLMSG_OK(nlMsg,len); nlMsg = NLMSG_NEXT(nlMsg,len)){memset(rtInfo, 0, sizeof(struct route_info));Joseph_ParseRoutes(nlMsg,rtInfo,gateway,if_name);}free(rtInfo);rtInfo = NULL;close(sock);return 0;}int main(int argc,char *argv[]){int itertion = 0;char gateway[16]={0};int Qy_Ret = 0;if(argc != 2){return -1;}while(itertion < 30){Qy_Ret = Joseph_Get_Gateway(gateway,argv[1]);if(Qy_Ret <0){return -1;}itertion++;printf("Gateway:%s\n", gateway);sleep(1);}return 0;}</span></span>