Linux网络配置代码

Linux下 配置网络接口比较简单， IP地址，掩码，缺省网管用ioctl,DNS直接操作/etc/resolv.conf文件就可以了。

 

void interface_configure(const char* address,               const char* netmask,               const char* gateway,               const char* dns1, const char* dns2){  ifreq ifr;  sockaddr_in saddr;  rtentry rte;  sockaddr_in rtdst;  sockaddr_in rtgw;  char buffer[1024];  int fd = socket(AF_INET, SOCK_DGRAM, 0);  if (fd == -1) {    fprintf(stderr,"Failed to create socket: %s", strerror(errno));    return;  }  // Following operation eq. to 'ifconfig eth0 <address> netmask <netmask>'  memset(&ifr, 0, sizeof(ifr));  strncpy(ifr.ifr_name, "eth0", IFNAMSIZ);  memset(&saddr, 0, sizeof(saddr));  saddr.sin_family = AF_INET;  inet_aton(address, &saddr.sin_addr);  memcpy(&ifr.ifr_addr, &saddr, sizeof(saddr));  if (ioctl(fd, SIOCSIFADDR, &ifr) == -1) {    fprintf(stderr, "Failed to set interface address %s: %s",                   address, strerror(errno));    return;  }    inet_aton(netmask,  (sockaddr_in*)(&(ifr.ifr_netmask.sin_addr));  if (ioctl(fd, SIOCSIFNETMASK, &ifr) == -1) {    fprintf(stderr, "Failed to set interface netmask %s: %s",                   netmask, strerror(errno));    return;  }  // route del default  memset(&rte, 0, sizeof(rte));  rte.rt_flags = RTF_UP | RTF_GATEWAY;  memset(&rtdst, 0, sizeof(rtdst));  rtdst.sin_family = AF_INET;  memcpy(&rte.rt_dst, &rtdst, sizeof(rtdst));  while (1) {    if (::ioctl(fd, SIOCDELRT, &rte) == -1) {      if (errno != ESRCH) {        fprintf(stderr, "Failed to delete gateway: %s", strerror(errno));      }      break;    }  }  // route add default gw <gatevay>  memset(&rtgw, 0, sizeof(rtgw));  rtgw.sin_family = AF_INET;  inet_aton(gateway, &rtgw.sin_addr);  memcpy(&rte.rt_gateway, &rtgw, sizeof(rtgw));  if (ioctl(fd, SIOCADDRT, &rte) == -1) {    fprintf(stderr, "Failed to add gateway %s: %s",                   gateway, strerror(errno));  }  close(fd);  // echo nameserver <dns1> > /etc/resolv.conf  // echo nameserver <dns2> >> /etc/resolv.conf  fd = creat("/etc/resolv.conf", 0666);  if (fd == -1) {    fprintf(stderr, "Failed to open  /etc/resolv.conf %s", strerror(errno));  }  else {    if (dns1 != NULL) {      snprintf(buffer, sizeof(buffer), "nameserver %s\n", dns1);      write(fd, buffer, strlen(buffer));    }     if (dns2 != NULL) {      snprintf(buffer, sizeof(buffer), "nameserver %s\n", dns2);      write(fd, buffer, strlen(buffer));    }    close(fd);  }}