net_util.c

 

       #define WIRED_DEV                   "eth0" 

    #define WIRELESS_DEV                "ra0"               #define PPPOE_DEV                   "ppp0"

#define DEBUG_PRT(fmt, arg...)      printf(fmt,##arg)

/**

 * get ip address. * @param net_dev net device. * @param ipaddr a pointer to save ip address. * @return 0 success, or fail. */int get_ipaddr(const char *net_dev,  char *ipaddr){     struct ifreq ifr;    int fd = 0;    struct sockaddr_in *pAddr;    if((NULL == net_dev) || (NULL == ipaddr))    {         DEBUG_PRT("illegal call function SetGeneralIP! \n");        return -1;    }    if((fd = socket(AF_INET,SOCK_DGRAM,0)) < 0)    {         DEBUG_PRT("open socket failed \n");        return -1;    }    memset(&ifr,0,sizeof(ifr));    strcpy(ifr.ifr_name, net_dev);    if(ioctl(fd, SIOCGIFADDR, &ifr) < 0)    {         DEBUG_PRT("SIOCGIFADDR socket failed \n");        close(fd);        return -1;    }    pAddr = (struct sockaddr_in *)&(ifr.ifr_addr);    strcpy(ipaddr, inet_ntoa(pAddr->sin_addr));        close(fd);        return 0;}/** * get gateway. * @param gateway a pointer to save geteway. * @return none. */void get_gateway(ITI_CHAR *gateway){     char buf[1024]={0};    char *p = NULL;    char *q = NULL;    int count = 0;    if(NULL == gateway)    {         DEBUG_PRT("gateway is NULL \n");        return;     }    cmd_run("route | grep default", buf, 1024);    if(0 == strlen(buf))    {         DEBUG_PRT("get gateway error \n");        return;    }    p = strstr2(buf, "default");    q = p;    while(*q == ' ')    {         q++;    }    p = q;    while(*p != ' ')    {         p++;        count++;    }    if(NULL != q)    {         memcpy(gateway, q, count);    }    gateway[count] = '\0';  }/** * get mask. * @param net_dev net device. * @param mask a pointer to save mask. * @return none. */void get_mask(const char *net_dev, ITI_CHAR *mask){     char buf[1024]={0};    char *p = NULL;    if(NULL == mask)    {         DEBUG_PRT("mask is NULL \n");        return;     }    if(0 == (memcmp(WIRED_DEV, net_dev, sizeof(WIRED_DEV))))    {         cmd_run("ifconfig eth0 | grep Mask", buf, 1024);    }    else if(0 == (memcmp(WIRELESS_DEV, net_dev, sizeof(WIRELESS_DEV))))    {         cmd_run("ifconfig ra0 | grep Mask", buf, 1024);    }    else if(0 == (memcmp(PPPOE_DEV, net_dev, sizeof(PPPOE_DEV))))    {         cmd_run("ifconfig ppp0 | grep Mask", buf, 1024);    }    else     {         DEBUG_PRT("net device not support \n");        return;     }        if(0 == strlen(buf))    {         DEBUG_PRT("get mask error \n");        return;    }    p = strstr2(buf, "Mask:");    if(NULL == p)    {         DEBUG_PRT("get mask error \n");        return;    }    strcpy(mask, p);}/** * get dns. * @param dns1 a pointer to save first dns. * @param dns2 a pointer to save second dns. * @return 0 success, or fail. */int get_dns(char *dns1, char *dns2){     int fd = -1;    int size = 0;    char strBuf[100];    char tmpBuf[100];    int buf_size = sizeof(strBuf);    char *p = NULL;    char *q = NULL;    int i = 0;    int j = 0;    int count = 0;        fd = open("/etc/resolv.conf", O_RDONLY);    if(-1 == fd)    {         DEBUG_PRT("%s open error \n", __func__);        return -1;    }    size = read(fd, strBuf, buf_size);    if(size < 0)    {         DEBUG_PRT("%s read file len error \n", __func__);        close(fd);        return -1;    }    strBuf[buf_size] = '\0';    close(fd);    while(i < buf_size)    {         if((p = strstr2(&strBuf[i], "nameserver")) != NULL)        {             j++;            p += 1;            count = 0;                        memset(tmpBuf, 0xff, 100);            memcpy(tmpBuf, p, 100);            tmpBuf[sizeof(tmpBuf) -1 ] = '\0';                        q = p;            while(*q != '\n')            {                 q++;                count++;            }            i += (sizeof("nameserver") + count);                        if(1 == j)            {                 memcpy(dns1, p, count);                dns1[count]='\0';            }            else if(2 == j)            {                 memcpy(dns2, p, count);                dns2[count]='\0';            }        }         else         {             i++;        }    }    return 0;}

 

main.c

void main(void)

{

        #define WIRED_DEV                   "eth0" 

    #define WIRELESS_DEV                "ra0"               #define PPPOE_DEV                   "ppp0"        char buf[1024] = {'\0'};    extern int get_ipaddr(const char *net_dev,  char *ipaddr);    get_ipaddr(WIRED_DEV, buf);    printf("get_ipaddr: %s \n", buf);    memset(buf, '\0', sizeof(buf));        extern void get_mask(const char *net_dev, ITI_CHAR *mask);    get_mask(WIRED_DEV, buf);    printf("get_mask: %s \n", buf);    memset(buf, '\0', sizeof(buf));        extern void get_gateway(ITI_CHAR *gateway);    get_gateway(buf);    printf("get_gateway: %s \n", buf);    memset(buf, '\0', sizeof(buf));    extern int get_dns(char *dns1, char *dns2);    get_dns(buf, &buf[100]);    printf("get_dns: %s %s\n", buf, &buf[100]);    memset(buf, '\0', sizeof(buf));

}

 

makefile:

gcc main.c net_util.c -o get_net_info

 

./get_net_info

运行结果:

get_ipaddr: 192.168.9.142 

get_mask: 255.255.255.0get_gateway: 192.168.9.254 get_dns: 192.168.9.11 192.168.9.10

 

 

为提高执行效率, 更新获取网关和子网掩码程序:

static void get_gateway(const char *net_dev, char *gateway)

{     FILE *fp;        char buf[1024];      char iface[16];        unsigned char tmp[100]={'\0'};    unsigned int dest_addr=0, gate_addr=0;    if(NULL == gateway)    {         DEBUG_PRT("gateway is NULL \n");        return;     }    fp = fopen("/proc/net/route", "r");        if(fp == NULL){          DEBUG_PRT("fopen error \n");        return;       }        fgets(buf, sizeof(buf), fp);        while(fgets(buf, sizeof(buf), fp))     {            if((sscanf(buf, "%s\t%X\t%X", iface, &dest_addr, &gate_addr) == 3)             && (memcmp(net_dev, iface, strlen(net_dev)) == 0)            && gate_addr != 0)         {                 memcpy(tmp, (unsigned char *)&gate_addr, 4);                sprintf(gateway, "%d.%d.%d.%d", (unsigned char)*tmp, (unsigned char)*(tmp+1), (unsigned char)*(tmp+2), (unsigned char)*(tmp+3));                break;            }    }              fclose(fp);}static void get_mask(const char *net_dev, ITI_CHAR *mask){     struct sockaddr_in *pAddr;    struct ifreq ifr;    int sockfd;    sockfd = socket(AF_INET,SOCK_DGRAM,0);    memset(&ifr,0,sizeof(ifr));    strcpy(ifr.ifr_name, net_dev);        if(ioctl(sockfd, SIOCGIFNETMASK, &ifr) < 0){         DEBUG_PRT("SIOCGIFADDR socket failed \n");        close(sockfd);        return ;    }    pAddr = (struct sockaddr_in *)&(ifr.ifr_addr);    strcpy(mask, (char *)(inet_ntoa(pAddr->sin_addr)));        close(sockfd);}