mac地址获取问题

实测发现拿这个mac地址意义不大，就算是在wifi情况下，同样的wifi，部分机型能拿到，部分机型拿不到，拿不到的情况下，还有获取时长问题，会影响到加载速度等问题，有可能导致闪退。
所以还是放弃了拿mac地址的想法了。

参考：
获取Wi-Fi Mac地址
获取Mac地址：返回的是020000000000

引入头文件

#include <ifaddrs.h>
#include <sys/socket.h> // Per msqr
#import <sys/ioctl.h>
#include <net/if.h>
#import <arpa/inet.h>
#import <sys/utsname.h>
#import <AdSupport/AdSupport.h>
#include <sys/sysctl.h>
#include <net/if_dl.h>
#import <resolv.h>
#import <netdb.h>
#import <netinet/ip.h>
#import <net/ethernet.h>

#define MDNS_PORT       5353
#define QUERY_NAME      "_apple-mobdev2._tcp.local"
#define DUMMY_MAC_ADDR  @"02:00:00:00:00:00"
#define IOS_CELLULAR    @"pdp_ip0"
#define IOS_WIFI        @"en0"
#define IOS_VPN         @"utun0"
#define IP_ADDR_IPv4    @"ipv4"
#define IP_ADDR_IPv6    @"ipv6"

获取对应Wi-Fi的mac地址

报res_9_init 等错误需要引入libresolv库
在Wi-Fi有网的情况下返回mac地址值：b8:c1:11:xd:5x:7a
其他情况下返回：020000000000

- (nullable NSString *)getMacAddress3 {
    res_9_init();
    int len;
    //get currnet ip address
    NSString *ip = [self currentIPAddressOf:IOS_WIFI];
    if(ip == nil) {
        fprintf(stderr, "could not get current IP address of en0\n");
        return DUMMY_MAC_ADDR;
    }//end if
    
    //set port and destination
    _res.nsaddr_list[0].sin_family = AF_INET;
    _res.nsaddr_list[0].sin_port = htons(MDNS_PORT);
    _res.nsaddr_list[0].sin_addr.s_addr = [self IPv4Pton:ip];
    _res.nscount = 1;
    
    unsigned char response[NS_PACKETSZ];
    
    
    //send mdns query
    if((len = res_9_query(QUERY_NAME, ns_c_in, ns_t_ptr, response, sizeof(response))) < 0) {
        
        fprintf(stderr, "res_search(): %s\n", hstrerror(h_errno));
        return DUMMY_MAC_ADDR;
    }//end if
    
    //parse mdns message
    ns_msg handle;
    if(ns_initparse(response, len, &handle) < 0) {
        fprintf(stderr, "ns_initparse(): %s\n", hstrerror(h_errno));
        return DUMMY_MAC_ADDR;
    }//end if
    
    //get answer length
    len = ns_msg_count(handle, ns_s_an);
    if(len < 0) {
        fprintf(stderr, "ns_msg_count return zero\n");
        return DUMMY_MAC_ADDR;
    }//end if
    
    //try to get mac address from data
    NSString *macAddress = nil;
    for(int i = 0 ; i < len ; i++) {
        ns_rr rr;
        ns_parserr(&handle, ns_s_an, 0, &rr);
        
        if(ns_rr_class(rr) == ns_c_in &&
           ns_rr_type(rr) == ns_t_ptr &&
           !strcmp(ns_rr_name(rr), QUERY_NAME)) {
            char *ptr = (char *)(ns_rr_rdata(rr) + 1);
            int l = (int)strcspn(ptr, "@");
            
            char *tmp = calloc(l + 1, sizeof(char));
            if(!tmp) {
                perror("calloc()");
                continue;
            }//end if
            memcpy(tmp, ptr, l);
            macAddress = [NSString stringWithUTF8String:tmp];
            free(tmp);
        }//end if
    }//end for each
    macAddress = macAddress ? macAddress : DUMMY_MAC_ADDR;
    return macAddress;
}//end

- (nonnull NSString *)currentIPAddressOf: (nonnull NSString *)device {
    struct ifaddrs *addrs;
    NSString *ipAddress = nil;
    
    if(getifaddrs(&addrs) != 0) {
        return nil;
    }//end if
    
    //get ipv4 address
    for(struct ifaddrs *addr = addrs ; addr ; addr = addr->ifa_next) {
        if(!strcmp(addr->ifa_name, [device UTF8String])) {
            if(addr->ifa_addr) {
                struct sockaddr_in *in_addr = (struct sockaddr_in *)addr->ifa_addr;
                if(in_addr->sin_family == AF_INET) {
                    ipAddress = [self IPv4Ntop:in_addr->sin_addr.s_addr];
                    break;
                }//end if
            }//end if
        }//end if
    }//end for
    
    freeifaddrs(addrs);
    return ipAddress;
}//end currentIPAddressOf:

- (nullable NSString *)IPv4Ntop: (in_addr_t)addr {
    char buffer[INET_ADDRSTRLEN] = {0};
    return inet_ntop(AF_INET, &addr, buffer, sizeof(buffer)) ?
    [NSString stringWithUTF8String:buffer] : nil;
}//end IPv4Ntop:

- (in_addr_t)IPv4Pton: (nonnull NSString *)IPAddr {
    in_addr_t network = INADDR_NONE;
    return inet_pton(AF_INET, [IPAddr UTF8String], &network) == 1 ?
    network : INADDR_NONE;
}//end IPv4Pton

获取mac地址：

拿到的数据是： 020000000000

- (NSString *)getmacaddress2
{
    
    int                 mib[6];
    size_t              len;
    char                *buf;
    unsigned char       *ptr;
    struct if_msghdr    *ifm;
    struct sockaddr_dl  *sdl;
    
    mib[0] = CTL_NET;
    mib[1] = AF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_LINK;
    mib[4] = NET_RT_IFLIST;
    
    if ((mib[5] = if_nametoindex("en0")) == 0) {
        printf("Error: if_nametoindex error/n");
        return NULL;
    }
    
    if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 1/n");
        return NULL;
    }
    
    if ((buf = malloc(len)) == NULL) {
        printf("Could not allocate memory. error!/n");
        return NULL;
    }
    
    if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 2");
        return NULL;
    }
    
    ifm = (struct if_msghdr *)buf;
    sdl = (struct sockaddr_dl *)(ifm + 1);
    ptr = (unsigned char *)LLADDR(sdl);
    NSString *outstring = [NSString stringWithFormat:@"%02x:%02x:%02x:%02x:%02x:%02x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
    
    //    NSString *outstring = [NSString stringWithFormat:@"%02x%02x%02x%02x%02x%02x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
    
    NSLog(@"outString:%@", outstring);
    
    free(buf);
    
    return [outstring uppercaseString];
}