linux 判断是否是合法ip，根据域名获取ip

朴灿烈づ我的快乐病毒、 2022-06-01 14:23 463阅读 0赞

//
    // Created by darren on 18-1-31.
    //
    
    #include <stdio.h>
    #include <netdb.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    
    bool isValidIP(const char *ipstr);
    
    int get_ip_by_domain(const char *domain, char *ip);
    
    void test_Big_endian();
    
    int is_valid_ip(const char *ip_str);
    
    
    int main(int argc, char *argv[]) {
    
        printf("isValidIP():%d\n", isValidIP(argv[1]));
        printf("is_valid_ip:%d\n", is_valid_ip(argv[1]));
    
        char tmp[256];
        int ret = get_ip_by_domain(argv[1], tmp);
        printf("domain:%d,%s\n", ret, tmp);
    
        test_Big_endian();
    
        return 0;
    }
    
    
    int is_valid_ip(const char *ip_str) {
        struct sockaddr_in sa;
        int result = inet_pton(AF_INET, ip_str, &(sa.sin_addr));
        if (result == 0) {
            return result;
        }
        return 1;
    }
    
    void test_Big_endian() {
        unsigned long a = 0x12345678;
        unsigned char *p = (unsigned char *) (&a);
        printf("主机字节序:%0x    %0x   %0x   %0x\n", p[0], p[1], p[2], p[3]);
        unsigned long b = htonl(a);  //将主机字节序转化成了网络字节序
        p = (unsigned char *) (&b);
        printf("网络字节序:%0x    %0x   %0x   %0x\n", p[0], p[1], p[2], p[3]);
    
    }
    
    //根据域名获取ip
    int get_ip_by_domain(const char *domain, char *ip) {
        char **pptr;
        struct hostent *hptr;
        hptr = gethostbyname(domain);
        if (NULL == hptr) {
            printf("gethostbyname error for host:%s/n", domain);
            return -1;
        }
        for (pptr = hptr->h_addr_list; *pptr != NULL; pptr++) {
            if (NULL != inet_ntop(hptr->h_addrtype, *pptr, ip, INET_ADDRSTRLEN)) {
                return 0; // 只获取第一个 ip
            }
        }
        return -1;
    }
    
    // ip 合法性
    bool isValidIP(const char *ipstr) {
        if (!ipstr) return false;
        int a, b, c, d;
        int tmp = sscanf(ipstr, "%d.%d.%d.%d", &a, &b, &c, &d);
        printf("tmp:%d\n", tmp);
        if (4 != tmp) return false;
        printf("inet_addr:%d,%d,%d,%d,%d\n", inet_addr(ipstr), a, b, c, d);
        if (!(0 > a || 255 < a ||
              0 > b || 255 < b ||
              0 > c || 255 < c ||
              0 > d || 255 < d) && INADDR_NONE != inet_addr(ipstr)) {
            return true;
        }
        return false;
    }