ifconfig

ifconfig

#include   
#include   
#include   
#include   
#include   
#include   
#include   
#include   
#include
#define MAC_LEN 6
#define name_len 16

typedef struct ifaddr_s
{
char if_name[IFNAMSIZ];                //The name of interface
short if_flags;                                //device flags: AFF_XXX
unsigned char if_haddr[MAC_LEN];  //MAC ADDRESS

struct sockaddr *if_addr;             //ip address
struct sockaddr *if_broadaddr;   //broadcast address
struct sockaddr *if_detaddr;
struct sockaddr *if_maskaddr;
struct ifaddr_s *next;
}ifaddr_t;

struct ifconf *
getMacConf()
{
struct ifconf *ifc;
int sockfd;
int len, last_len;
char *buf;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
ifc = (struct ifconf *)malloc(sizeof(struct ifconf));
len = 10 * sizeof(struct ifreq);
last_len = 0;
while(1){
  buf = (char *)malloc(len);
  ifc->ifc_len = len;
  ifc->ifc_buf = buf;
  if(ioctl(sockfd, SIOCGIFCONF, ifc) < 0)
  {
   if(errno != EINVAL || last_len != 0)
   {
    printf("ioctl error\n");
    free(ifc);
    free(buf);
    return NULL;
   }
  }
  else{
   if(last_len == ifc->ifc_len)
    break;
   last_len = ifc->ifc_len;
  }
  len += 10 * sizeof(struct ifreq);
  free(buf);
}
close(sockfd);
return ifc;
}
struct ifaddr_s *
get_ifaddr(struct ifconf *ifc)
{
char *ptr, *buf, *cptr;
ifaddr_t *ifa=NULL, *ifa_next;
struct ifreq *ifr;
char lastname[name_len];
int sockfd;
int flags;
int len;
struct sockaddr_in *sin_addr;

if(ifc == NULL)
{
  printf("ifc is NULL\n");
  return NULL;
}
lastname[0] = 0;
buf = ifc->ifc_buf;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
for(ptr = buf; ptr < buf + ifc->ifc_len;)
{
  ifr = (struct ifreq *)ptr;
  //ioctl(sockfd, SIOCGIFADDR, ifr);
#ifdef HAVE_SOCKADDR_SA_LEN
  len = sizeof(struct sockaddr)>(ifr->ifr_addr.sa_len)?sizeof(struct sockaddr):(ifr->ifr_addr.sa_len);
#else
  switch(ifr->ifr_addr.sa_family)
  {
#ifdef  IPV6
   case AF_INET6:
    len = sizeof(struct sockaddr_in6);
    break;
#endif
   case AF_INET:
   default:
    len = sizeof(struct sockaddr_in);
    break;
  }
#endif
  ptr += sizeof(ifr->ifr_name) + len;
  //ignore IPV6
  if(ifr->ifr_addr.sa_family != AF_INET)
   continue;
  if((cptr = strchr(ifr->ifr_name, ':')) != NULL)
   *cptr = 0;
  if(strncmp(lastname, ifr->ifr_name, IFNAMSIZ) == 0)
  {
   continue;
  }
  strncpy(lastname, ifr->ifr_name, sizeof(lastname));
  ioctl(sockfd, SIOCGIFFLAGS, ifr);
  flags = ifr->ifr_flags;
  if((flags&IFF_UP) == 0)
   continue;
  ifa_next = calloc(1, sizeof(ifaddr_t));
  ifa_next->next = ifa;
  ifa = ifa_next;
  strncpy(ifa->if_name, ifr->ifr_name, sizeof(ifa->if_name));
  ifa->if_flags = flags;
  ioctl(sockfd, SIOCGIFADDR, ifr);
  switch(ifr->ifr_addr.sa_family)
  {
   case AF_INET:
    sin_addr = (struct sockaddr_in *)&ifr->ifr_addr;
    if(ifa->if_addr != NULL)
     break;
    ifa->if_addr = calloc(1, sizeof(struct sockaddr_in));
    memcpy(ifa->if_addr, sin_addr, sizeof(struct sockaddr));
   #ifdef SIOCGIFBRDADDR
    if(flags&IFF_BROADCAST)
    {
     ioctl(sockfd, SIOCGIFBRDADDR, ifr);
     sin_addr = (struct sockaddr_in *)&ifr->ifr_broadaddr;
     ifa->if_broadaddr = calloc(1, sizeof(struct sockaddr_in));
     memcpy(ifa->if_broadaddr, sin_addr, sizeof(struct sockaddr_in));
    }
   #endif
   #ifdef SIOCGIFDSTADDR
    if(flags&IFF_POINTOPOINT)
    {
     ioctl(sockfd, SIOCGIFDSTADDR, ifr);
     sin_addr = (struct sockaddr_in *)&ifr->ifr_dstaddr;
     ifa->if_detaddr = calloc(1, sizeof(struct sockaddr_in));
     memcpy(ifa->if_detaddr, sin_addr, sizeof(struct sockaddr_in));
    }
   #endif
   #ifdef SIOCGIFHWADDR    
    if((flags&IFF_LOOPBACK) == 0)
    {
     ioctl(sockfd, SIOCGIFHWADDR, ifr);
     memcpy(ifa->if_haddr, ifr->ifr_hwaddr.sa_data, MAC_LEN);
    }
   #endif
        #ifdef SIOCGIFNETMASK
    if((flags&IFF_LOOPBACK) == 0)
    {
     ioctl(sockfd, SIOCGIFNETMASK, ifr);
     sin_addr = (struct sockaddr_in *)&ifr->ifr_netmask;
     ifa->if_maskaddr = calloc(1, sizeof(struct sockaddr_in));
     memcpy(ifa->if_maskaddr, sin_addr, sizeof(struct sockaddr_in));
    }
   #endif
  }
}
close(sockfd);
return ifa;
}

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本文地址：http://qzone.qq.com/blog/271783199-1207708741