「微服务的细节」—— 如何获取本地 IP？

bool NetClient::GetIpByIf(const std::string& ifname, std::string* ip) {  if (ifname.empty() || ip == NULL) {    return false;  }  int fd, intrface;  struct ifreq buf[10];  struct ifconf ifc = {0, {0}};  memset(buf, 0, sizeof(buf));  struct in_addr addr;  char addr_buffer[32] = {0};
  if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) >= 0) {    ifc.ifc_len = sizeof(buf);    ifc.ifc_buf = (caddr_t)buf;    if (!ioctl(fd, SIOCGIFCONF, &ifc)) {      intrface = ifc.ifc_len / sizeof(struct ifreq);      while (intrface-- > 0) {        if (strcmp(buf[intrface].ifr_name, ifname.c_str()) == 0) {          if (!(ioctl(fd, SIOCGIFADDR, &buf[intrface]))) {            memset(addr_buffer, 0, sizeof(addr_buffer));            addr = ((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr;            if (inet_ntop(AF_INET, static_cast<void*>(&addr), addr_buffer, sizeof(addr_buffer))) {              ip->assign(addr_buffer);              close(fd);              return true;            }          }          break;        }      }    }    close(fd);  }  return false;}

bool NetClient::GetIpByConnect(std::string* ip) {  std::vector<SeedServer> default_servers;  SeedServerConfig::GetDefaultSeedServer(default_servers);  POLARIS_ASSERT(!default_servers.empty());  SeedServer& server = default_servers[time(NULL) % default_servers.size()];
  int socket_fd = CreateTcpSocket(true);  if (socket_fd < 0) {    POLARIS_LOG(LOG_ERROR, "get local ip by connect to server[%s:%d] with create socket errno: %d",                server.ip_.c_str(), server.port_, errno);    return false;  }  ConnectWithTimeout(socket_fd, server.ip_, server.port_, 200);  struct sockaddr_in addr;  socklen_t len = sizeof(addr);  if (getsockname(socket_fd, (struct sockaddr*)&addr, &len) < 0) {    POLARIS_LOG(LOG_INFO, "get local ip by connect to server[%s:%d] with errno: %d",                server.ip_.c_str(), server.port_, errno);    CloseNoLinger(socket_fd);    return false;  }  ip->assign(inet_ntoa(addr.sin_addr));  CloseNoLinger(socket_fd);  return true;}