获取iOS设备当前ip地址

第一种方法是用系统api的方式获取，如下

#include <stdio.h>  
#include <stdlib.h>  
#include <string.h>  
#include <unistd.h>  
#include <sys/ioctl.h>  
#include <sys/types.h>  
#include <sys/socket.h>  
#include <netinet/in.h>  
#include <netdb.h>  
#include <arpa/inet.h>  
#include <sys/sockio.h>  
#include <net/if.h>  
#include <errno.h>  
#include <net/if_dl.h>  
  
//#include "GetAddresses.h"  
  
#define min(a,b)    ((a) < (b) ? (a) : (b))  
#define max(a,b)    ((a) > (b) ? (a) : (b))  
  
#define BUFFERSIZE  4000  
  
char *if_names[MAXADDRS];  
char *ip_names[MAXADDRS];  
char *hw_addrs[MAXADDRS];  
unsigned long ip_addrs[MAXADDRS];  
  
static int   nextAddr = 0;  
  
void InitAddresses()  
{  
    int i;  
    for (i=0; i<MAXADDRS; ++i)  
    {  
        if_names[i] = ip_names[i] = hw_addrs[i] = NULL;  
        ip_addrs[i] = 0;  
    }  
}  
  
void FreeAddresses()  
{  
    int i;  
    for (i=0; i<MAXADDRS; ++i)  
    {  
        if (if_names[i] != 0) free(if_names[i]);  
        if (ip_names[i] != 0) free(ip_names[i]);  
        if (hw_addrs[i] != 0) free(hw_addrs[i]);  
        ip_addrs[i] = 0;  
    }  
    InitAddresses();  
}  
  
void GetIPAddresses()  
{  
    int                 i, len, flags;  
    char                buffer[BUFFERSIZE], *ptr, lastname[IFNAMSIZ], *cptr;  
    struct ifconf       ifc;  
    struct ifreq        *ifr, ifrcopy;  
    struct sockaddr_in  *sin;  
      
    char temp[80];  
      
    int sockfd;  
      
    for (i=0; i<MAXADDRS; ++i)  
    {  
        if_names[i] = ip_names[i] = NULL;  
        ip_addrs[i] = 0;  
    }  
      
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);  
    if (sockfd < 0)  
    {  
        perror("socket failed");  
        return;  
    }  
      
    ifc.ifc_len = BUFFERSIZE;  
    ifc.ifc_buf = buffer;  
      
    if (ioctl(sockfd, SIOCGIFCONF, &ifc) < 0)  
    {  
        perror("ioctl error");  
        return;  
    }  
      
    lastname[0] = 0;  
      
    for (ptr = buffer; ptr < buffer + ifc.ifc_len; )  
    {  
        ifr = (struct ifreq *)ptr;  
        len = max(sizeof(struct sockaddr), ifr->ifr_addr.sa_len);  
        ptr += sizeof(ifr->ifr_name) + len;  // for next one in buffer  
          
        if (ifr->ifr_addr.sa_family != AF_INET)  
        {  
            continue;   // ignore if not desired address family  
        }  
          
        if ((cptr = (char *)strchr(ifr->ifr_name, ':')) != NULL)  
        {  
            *cptr = 0;      // replace colon will null  
        }  
          
        if (strncmp(lastname, ifr->ifr_name, IFNAMSIZ) == 0)  
        {  
            continue;   /* already processed this interface */  
        }  
          
        memcpy(lastname, ifr->ifr_name, IFNAMSIZ);  
          
        ifrcopy = *ifr;  
        ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy);  
        flags = ifrcopy.ifr_flags;  
        if ((flags & IFF_UP) == 0)  
        {  
            continue;   // ignore if interface not up  
        }  
          
        if_names[nextAddr] = (char *)malloc(strlen(ifr->ifr_name)+1);  
        if (if_names[nextAddr] == NULL)  
        {  
            return;  
        }  
        strcpy(if_names[nextAddr], ifr->ifr_name);  
          
        sin = (struct sockaddr_in *)&ifr->ifr_addr;  
        strcpy(temp, inet_ntoa(sin->sin_addr));  
          
        ip_names[nextAddr] = (char *)malloc(strlen(temp)+1);  
        if (ip_names[nextAddr] == NULL)  
        {  
            return;  
        }  
        strcpy(ip_names[nextAddr], temp);  
          
        ip_addrs[nextAddr] = sin->sin_addr.s_addr;  
          
        ++nextAddr;  
    }  
      
    close(sockfd);  
}  
  
void GetHWAddresses()  
{  
    struct ifconf ifc;  
    struct ifreq *ifr;  
    int i, sockfd;  
    char buffer[BUFFERSIZE], *cp, *cplim;  
    char temp[80];  
      
    for (i=0; i<MAXADDRS; ++i)  
    {  
        hw_addrs[i] = NULL;  
    }  
      
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);  
    if (sockfd < 0)  
    {  
        perror("socket failed");  
        return;  
    }  
      
    ifc.ifc_len = BUFFERSIZE;  
    ifc.ifc_buf = buffer;  
      
    if (ioctl(sockfd, SIOCGIFCONF, (char *)&ifc) < 0)  
    {  
        perror("ioctl error");  
        close(sockfd);  
        return;  
    }  
      
    ifr = ifc.ifc_req;  
      
    cplim = buffer + ifc.ifc_len;  
      
    for (cp=buffer; cp < cplim; )  
    {  
        ifr = (struct ifreq *)cp;  
        if (ifr->ifr_addr.sa_family == AF_LINK)  
        {  
            struct sockaddr_dl *sdl = (struct sockaddr_dl *)&ifr->ifr_addr;  
            int a,b,c,d,e,f;  
            int i;  
              
            strcpy(temp, (char *)ether_ntoa(LLADDR(sdl)));  
            sscanf(temp, "%x:%x:%x:%x:%x:%x", &a, &b, &c, &d, &e, &f);  
            sprintf(temp, "%02X:%02X:%02X:%02X:%02X:%02X",a,b,c,d,e,f);  
              
            for (i=0; i<MAXADDRS; ++i)  
            {  
                if ((if_names[i] != NULL) && (strcmp(ifr->ifr_name, if_names[i]) == 0))  
                {  
                    if (hw_addrs[i] == NULL)  
                    {  
                        hw_addrs[i] = (char *)malloc(strlen(temp)+1);  
                        strcpy(hw_addrs[i], temp);  
                        break;  
                    }  
                }  
            }  
        }  
        cp += sizeof(ifr->ifr_name) + max(sizeof(ifr->ifr_addr), ifr->ifr_addr.sa_len);  
    }  
      
    close(sockfd);  
}  

- (NSString *)deviceIPAdress {  
    InitAddresses();  
    GetIPAddresses();  
    GetHWAddresses();  
  
    return [NSString stringWithFormat:@"%s", ip_names[1]];  
} 

这样得到的ip，如果在内网中，那么就是内网的ip.
第二种方法是可以获取公网ip

- (void)getCurrentIP  
{  
    NSURL *url = [NSURL URLWithString:@"http://automation.whatismyip.com/n09230945.asp"];  
    __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];  
    [request setCompletionBlock:^{  
        NSString *responseString = [request responseString];  
        if (responseString) {  
              
            NSString *ip = [NSString stringWithFormat:@"%@", responseString];  
              
            NSLog(@"responseString = %@", ip);  
        };  
          
    }];  
      
    [request setFailedBlock:^{  
    }];  
}  

用到了ASIHTTPRequest这个网络开源库。
http://automation.whatismyip.com/n09230945.asp这个http url就可以获取你当前的ip地址。