本文转载至 http://blog.csdn.net/arthurchenjs/article/details/6358489

这是获取网卡的硬件地址的代码，如果无法编译通过，记得把下面的这几个头文件加上把。

#include <sys/socket.h> // Per msqr
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>

#pragma mark MAC addy
// Return the local MAC addy
// Courtesy of FreeBSD hackers email list
// Accidentally munged during previous update. Fixed thanks to mlamb.
- (NSString *) macaddress
{
    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)];
    free(buf);
    return [outstring uppercaseString];
}

这写头文件是用于获取ip等系列功能的
#include <arpa/inet.h>
#include <netdb.h>

#include <net/if.h>

#include <ifaddrs.h>
#import <dlfcn.h>
#import "wwanconnect.h//frome apple 你可能没有哦

#import <SystemConfiguration/SystemConfiguration.h>

获取ip地址的代码有很多

这是外网可见的ip地址，如果你在小区的局域网中，那就是小区的，不是局域网的内网地址。

- (NSString *) whatismyipdotcom
{
    NSError *error;
    NSURL *ipURL = [NSURL URLWithString:@"http://www.whatismyip.com/automation/n09230945.asp"];
    NSString *ip = [NSString stringWithContentsOfURL:ipURL encoding:1 error:&error];
    return ip ? ip : [error localizedDescription];
}

这是获取本地wifi的ip地址

// Matt Brown‘s get WiFi IP addy solution
// Author gave permission to use in Cookbook under cookbook license
// http://mattbsoftware.blogspot.com/2009/04/how-to-get-ip-address-of-iphone-os-v221.html
- (NSString *) localWiFiIPAddress
{
    BOOL success;
    struct ifaddrs * addrs;
    const struct ifaddrs * cursor;
    
    success = getifaddrs(&addrs) == 0;
    if (success) {
        cursor = addrs;
        while (cursor != NULL) {
            // the second test keeps from picking up the loopback address
            if (cursor->ifa_addr->sa_family == AF_INET && (cursor->ifa_flags & IFF_LOOPBACK) == 0) 
            {
                NSString *name = [NSString stringWithUTF8String:cursor->ifa_name];
                if ([name isEqualToString:@"en0"])  // Wi-Fi adapter
                    return [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)cursor->ifa_addr)->sin_addr)];
            }
            cursor = cursor->ifa_next;
        }
        freeifaddrs(addrs);
    }
    return nil;
}

NSString和Address的转换

+ (NSString *) stringFromAddress: (const struct sockaddr *) address
{
    if(address && address->sa_family == AF_INET) {
        const struct sockaddr_in* sin = (struct sockaddr_in*) address;
        return [NSString stringWithFormat:@"%@:%d", [NSString stringWithUTF8String:inet_ntoa(sin->sin_addr)], ntohs(sin->sin_port)];
    }
    
    return nil;
}

+ (BOOL)addressFromString:(NSString *)IPAddress address:(struct sockaddr_in *)address
{
    if (!IPAddress || ![IPAddress length]) {
        return NO;
    }
    
    memset((char *) address, sizeof(struct sockaddr_in), 0);
    address->sin_family = AF_INET;
    address->sin_len = sizeof(struct sockaddr_in);
    
    int conversionResult = inet_aton([IPAddress UTF8String], &address->sin_addr);
    if (conversionResult == 0) {
        NSAssert1(conversionResult != 1, @"Failed to convert the IP address string into a sockaddr_in: %@", IPAddress);
        return NO;
    }
    
    return YES;
}
获取host的名称
- (NSString *) hostname
{
    char baseHostName[256]; // Thanks, Gunnar Larisch
    int success = gethostname(baseHostName, 255);
    if (success != 0) return nil;
    baseHostName[255] = ‘/0‘;
    
#if TARGET_IPHONE_SIMULATOR
     return [NSString stringWithFormat:@"%s", baseHostName];
#else
    return [NSString stringWithFormat:@"%s.local", baseHostName];
#endif
}
从host获取地址
- (NSString *) getIPAddressForHost: (NSString *) theHost
{
    struct hostent *host = gethostbyname([theHost UTF8String]);
    if (!host) {herror("resolv"); return NULL; }
    struct in_addr **list = (struct in_addr **)host->h_addr_list;
    NSString *addressString = [NSString stringWithCString:inet_ntoa(*list[0]) encoding:NSUTF8StringEncoding];
    return addressString;
}

这是本地host的IP地址
- (NSString *) localIPAddress
{
    struct hostent *host = gethostbyname([[self hostname] UTF8String]);
    if (!host) {herror("resolv"); return nil;}
    struct in_addr **list = (struct in_addr **)host->h_addr_list;
    return [NSString stringWithCString:inet_ntoa(*list[0]) encoding:NSUTF8StringEncoding];
}