上一篇分析了接入设备的首次浏览器访问请求如何通过 防火墙过滤规则 重定向到 wifidog 的 HTTP 服务中,本篇主要分析了 wifidog 在接收到 接入设备的 HTTP 访问请求后,如何将此 HTTP 请求重定向到 认证服务器(auth-server) 上。
通过上面的防火墙规则,会将通过上面的防火墙规则,会将HTTP请求的外部IP地址和端口通过NAT方式重定向至本地wifidog内嵌HTTP服务器的地址和端口上,并由内嵌HTTP服务器进行服务,而内嵌HTTP服务器的路径和回调处理如下:
[cpp] view plaincopy
- if ((webserver = httpdCreate(config->gw_address, config->gw_port)) == NULL) {
- debug(LOG_ERR, "Could not create web server: %s", strerror(errno));
- exit(1);
- }
- debug(LOG_DEBUG, "Assigning callbacks to web server");
- httpdAddCContent(webserver, "/", "wifidog", 0, NULL, http_callback_wifidog);
- httpdAddCContent(webserver, "/wifidog", "", 0, NULL, http_callback_wifidog);
- httpdAddCContent(webserver, "/wifidog", "about", 0, NULL, http_callback_about);
- httpdAddCContent(webserver, "/wifidog", "status", 0, NULL, http_callback_status);
- httpdAddCContent(webserver, "/wifidog", "auth", 0, NULL, http_callback_auth);
- httpdAddC404Content(webserver, http_callback_404);
客户端首次访问时回调客户端首次访问时回调http_callback_404函数,在该函数中根据获取的客户端信息来配置重定向的URL fragment,如下:
[cpp] view plaincopy
- void
- http_callback_404(httpd *webserver, request *r)
- {
- char tmp_url[MAX_BUF],
- *url,
- *mac;
- s_config *config = config_get_config();
- t_auth_serv *auth_server = get_auth_server();
- memset(tmp_url, 0, sizeof(tmp_url));
- /*
- * XXX Note the code below assumes that the client‘s request is a plain
- * http request to a standard port. At any rate, this handler is called only
- * if the internet/auth server is down so it‘s not a huge loss, but still.
- */ /* 用户需要访问的URL */
- snprintf(tmp_url, (sizeof(tmp_url) - 1), "http://%s%s%s%s",
- r->request.host,
- r->request.path,
- r->request.query[0] ? "?" : "",
- r->request.query);
- url = httpdUrlEncode(tmp_url);
- if (!is_online()) {
- /* 路由器都接入不到 internet */
- char * buf;
- send_http_page(r, "Uh oh! Internet access unavailable!", buf);
- free(buf);
- }
- else if (!is_auth_online()) {
- /* auth server 挂起 */
- char * buf;
- send_http_page(r, "Uh oh! Login screen unavailable!", buf);
- free(buf);
- }
- else {
- /* 配置重定向到 auth server 的 url 参数 */
- char *urlFragment;
- if (!(mac = arp_get(r->clientAddr))) {
- /* We could not get their MAC address */
- debug(LOG_INFO, "Failed to retrieve MAC address for ip %s, so not putting in the login request", r->clientAddr);
- safe_asprintf(&urlFragment, "%sgw_address=%s&gw_port=%d&gw_id=%s&url=%s",
- auth_server->authserv_login_script_path_fragment,
- config->gw_address,
- config->gw_port,
- config->gw_id,
- url);
- } else {
- debug(LOG_INFO, "Got client MAC address for ip %s: %s", r->clientAddr, mac);
- safe_asprintf(&urlFragment, "%sgw_address=%s&gw_port=%d&gw_id=%s&mac=%s&url=%s",
- auth_server->authserv_login_script_path_fragment,
- config->gw_address,
- config->gw_port,
- config->gw_id,
- mac,
- url);
- }
- /* 调用该函数将用户请求重定向到 auth server 的登录页面 */
- http_send_redirect_to_auth(r, urlFragment, "Redirect to login page");
- free(urlFragment);
- }
- free(url);
- }
上面代码基本不用解释,具体重定向至auth server的消息在下面的 http_send_redirect_to_auth 函数中实现:
[cpp] view plaincopy
- void http_send_redirect_to_auth(request *r, char *urlFragment, char *text)
- {
- char *protocol = NULL;
- int port = 80;
- t_auth_serv *auth_server = get_auth_server();
- if (auth_server->authserv_use_ssl) {
- protocol = "https";
- port = auth_server->authserv_ssl_port;
- } else {
- protocol = "http";
- port = auth_server->authserv_http_port;
- }
- char *url = NULL;
- safe_asprintf(&url, "%s://%s:%d%s%s",
- protocol,
- auth_server->authserv_hostname,
- port,
- auth_server->authserv_path,
- urlFragment
- );
- http_send_redirect(r, url, text);
- free(url);
- }
具体的重定向URL给个实例:
POST /login/?gw_address=192.168.1.1&gw_port=2060&gw_id=default&mac=44:94:fc:ef:28:40&url=http%3A//www.baidu.com/ HTTP/1.1
可以看到这里有这几个参数信息:
2gw_address,路由器的LAN地址
2gw_port:为wifidog的监听端口
2gw_id:路由器的标识名
2mac:客户端设备的MAC地址
2url:为客户端访问的原URL(以便于重定向)
wifidog 源码初分析(2)-转
时间: 2024-11-08 02:15:24