utils.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <errno.h>
#include <ctype.h>

#include <net/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <linux/if_link.h>

#include "utils.h"

// s_sleep using select instead of sleep
// s: second, u: usec 10^6usec = 1s

//使用select来搞定sleep,精确度高
void s_sleep(unsigned int s, unsigned int u)
{
    struct timeval timeout;

    timeout.tv_sec  = s;
    timeout.tv_usec = u;
    select(0, NULL, NULL, NULL, &timeout);
}

// is_valid_ip_address:
// return 0:ipaddress unlegal
//验证ip地址字符串是否有效,inet_pton()
int is_valid_ip_address(const char *ip_address)
{
    struct sockaddr_in sa;
    int result = inet_pton(AF_INET, ip_address, &(sa.sin_addr));
    return result;
}

//	net_if_name: name of network interface, e.g. br-lan
//	return: 1: error 0:get succeed
//直接调用SIOCGETIFHWADDR来获取mac地址
int get_net_mac(char *net_if_name, char *mac, int mac_len)
{
    int ret  = 1;
    int i    = 0;
    int sock = 0;

    if (mac_len < 12 || net_if_name == NULL) {
        return 1;
    }
    struct ifreq ifreq;

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("error sock");
        goto OUT;
    }

    strncpy(ifreq.ifr_name, net_if_name, IFNAMSIZ);
    if (ioctl(sock, SIOCGIFHWADDR, &ifreq) < 0) {
        perror("error ioctl");
        goto OUT;
    }

    for (i = 0; i < 6; i++) {
        snprintf(mac + 2 * i, mac_len - 2 * i, "%02X", (unsigned char) ifreq.ifr_hwaddr.sa_data[i]);
    }
    mac[strlen(mac)] = 0;
    ret              = 0;

OUT:
    close(sock);
    return ret;
}

// return: -1: network interface check failed; other: ifname numbers
// ifconfig的实现???
int show_net_ifname()
{
    struct ifaddrs *ifaddr, *ifa;
    int family, s, n;
    char host[NI_MAXHOST];

    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }

    /* Walk through linked list, maintaining head pointer so we
      can free list later */

    for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa->ifa_next, n++) {
        if (ifa->ifa_addr == NULL)
            continue;

        family = ifa->ifa_addr->sa_family;

        /* Display interface name and family (including symbolic
        form of the latter for the common families) */

        printf("%-8s %s (%d)\n", ifa->ifa_name,
               (family == AF_PACKET)
                   ? "AF_PACKET"
                   : (family == AF_INET) ? "AF_INET" : (family == AF_INET6) ? "AF_INET6" : "???",
               family);

        /* For an AF_INET* interface address, display the address */

        if (family == AF_INET || family == AF_INET6) {
            s = getnameinfo(
                ifa->ifa_addr,
                (family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6),
                host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
            if (s != 0) {
                printf("getnameinfo() failed: %s\n", gai_strerror(s));
                exit(EXIT_FAILURE);
            }

            printf("\t\taddress: <%s>\n", host);

        } else if (family == AF_PACKET && ifa->ifa_data != NULL) {
            struct rtnl_link_stats *stats = (struct rtnl_link_stats *) ifa->ifa_data;

            printf(
                "\t\ttx_packets = %10u; rx_packets = %10u\n"
                "\t\ttx_bytes   = %10u; rx_bytes   = %10u\n",
                stats->tx_packets, stats->rx_packets, stats->tx_bytes, stats->rx_bytes);
        }
    }

    freeifaddrs(ifaddr);
    return 0;
}

// return: 0: network interface get succeed
int get_net_ifname(char *if_buf, int blen)
{
    if (NULL == if_buf || blen < 8)
        return -1;

    struct ifaddrs *ifaddr, *ifa;
    int family, n;
    int ret = 1;
    //读取ifaddr链首
    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }

    int found = 0;
    char tmp_if_buf[16];
    memset(tmp_if_buf, 0, sizeof(tmp_if_buf));
    /* Walk through linked list, maintaining head pointer so we
      can free list later */
    for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa->ifa_next, n++) {
        if (ifa->ifa_addr == NULL)
            continue;

        family = ifa->ifa_addr->sa_family;

        if (family == AF_INET) {
            // for LEDE/OpenWRT embedded router os
            //取br-lan接口
            if (strcmp(ifa->ifa_name, "br-lan") == 0) {
                found = 1;
                break;
            }
        } else if (family == AF_PACKET && ifa->ifa_data != NULL &&
                   strcmp(ifa->ifa_name, "lo") != 0) {   // skip local loop interface
            //取最后一个非lo接口
            strncpy(tmp_if_buf, ifa->ifa_name, 16);
        }
    }

    if (found) {
        strncpy(if_buf, ifa->ifa_name, blen);
        ret = 0;
    } else if (tmp_if_buf[0] != 0) {
        strncpy(if_buf, tmp_if_buf, blen);
        ret = 0;
    }

    //释放
    freeifaddrs(ifaddr);
    return ret;
}

// e.g. wWw.Baidu.com/China will be trans into www.baidu.com/China
// return: 0:check and trant succeed, 1:failed or domain name is invalid

// dns格式化
int dns_unified(const char *dname, char *udname_buf, int udname_buf_len)
{
    if (!dname || !udname_buf || udname_buf_len < strlen(dname) + 1)
        return 1;

    int has_dot = 0;
    int dlen    = strlen(dname);
    int i       = 0;
    for (i = 0; i < dlen; i++) {
        if (dname[i] == '/')
            break;

        if (dname[i] == '.' && i != dlen - 1)
            has_dot = 1;

        udname_buf[i] = tolower(dname[i]);
    }

    if (!has_dot)   // domain name should have 1 dot leastly
        return 1;

    return 0;
}