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wifidog 源码初分析(2)-转

时间:2014-06-25 13:08:45      阅读:213      评论:0      收藏:0      [点我收藏+]

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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:

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  1. if ((webserver = httpdCreate(config->gw_address, config->gw_port)) == NULL) {  
  2.     debug(LOG_ERR, "Could not create web server: %s", strerror(errno));  
  3.     exit(1);  
  4. }  
  5. debug(LOG_DEBUG, "Assigning callbacks to web server");  
  6. httpdAddCContent(webserver, "/", "wifidog", 0, NULL, http_callback_wifidog);  
  7. httpdAddCContent(webserver, "/wifidog", "", 0, NULL, http_callback_wifidog);  
  8. httpdAddCContent(webserver, "/wifidog", "about", 0, NULL, http_callback_about);  
  9. httpdAddCContent(webserver, "/wifidog", "status", 0, NULL, http_callback_status);  
  10. httpdAddCContent(webserver, "/wifidog", "auth", 0, NULL, http_callback_auth);  
  11. 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:

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  1. void
  2. http_callback_404(httpd *webserver, request *r)  
  3. {  
  4. char tmp_url[MAX_BUF],  
  5.             *url,  
  6.             *mac;  
  7.     s_config    *config = config_get_config();  
  8.     t_auth_serv *auth_server = get_auth_server();  
  9.     memset(tmp_url, 0, sizeof(tmp_url));  
  10. /*
  11.      * XXX Note the code below assumes that the client‘s request is a plain
  12.      * http request to a standard port. At any rate, this handler is called only
  13.      * if the internet/auth server is down so it‘s not a huge loss, but still.
  14.      */ /* 用户需要访问的URL */
  15.         snprintf(tmp_url, (sizeof(tmp_url) - 1), "http://%s%s%s%s",  
  16.                         r->request.host,  
  17.                         r->request.path,  
  18.                         r->request.query[0] ? "?" : "",  
  19.                         r->request.query);  
  20.     url = httpdUrlEncode(tmp_url);  
  21. if (!is_online()) {  
  22. /* 路由器都接入不到 internet */
  23. char * buf;  
  24.         send_http_page(r, "Uh oh! Internet access unavailable!", buf);  
  25.         free(buf);  
  26.     }  
  27. else if (!is_auth_online()) {  
  28. /* auth server 挂起 */
  29. char * buf;  
  30.         send_http_page(r, "Uh oh! Login screen unavailable!", buf);  
  31.         free(buf);  
  32.     }  
  33. else {  
  34. /* 配置重定向到 auth server 的 url 参数 */
  35. char *urlFragment;  
  36. if (!(mac = arp_get(r->clientAddr))) {  
  37. /* We could not get their MAC address */
  38.             debug(LOG_INFO, "Failed to retrieve MAC address for ip %s, so not putting in the login request", r->clientAddr);  
  39.             safe_asprintf(&urlFragment, "%sgw_address=%s&gw_port=%d&gw_id=%s&url=%s",  
  40.                 auth_server->authserv_login_script_path_fragment,  
  41.                 config->gw_address,  
  42.                 config->gw_port,  
  43.                 config->gw_id,  
  44.                 url);  
  45.         } else {            
  46.             debug(LOG_INFO, "Got client MAC address for ip %s: %s", r->clientAddr, mac);  
  47.             safe_asprintf(&urlFragment, "%sgw_address=%s&gw_port=%d&gw_id=%s&mac=%s&url=%s",  
  48.                 auth_server->authserv_login_script_path_fragment,  
  49.                 config->gw_address,  
  50.                 config->gw_port,  
  51.                 config->gw_id,  
  52.                 mac,  
  53.                 url);  
  54.         }  
  55. /* 调用该函数将用户请求重定向到 auth server 的登录页面 */
  56.         http_send_redirect_to_auth(r, urlFragment, "Redirect to login page");  
  57.         free(urlFragment);  
  58.     }  
  59.     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:

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  1. void http_send_redirect_to_auth(request *r, char *urlFragment, char *text)  
  2. {  
  3. char *protocol = NULL;  
  4. int port = 80;  
  5.     t_auth_serv *auth_server = get_auth_server();  
  6. if (auth_server->authserv_use_ssl) {  
  7.         protocol = "https";  
  8.         port = auth_server->authserv_ssl_port;  
  9.     } else {  
  10.         protocol = "http";  
  11.         port = auth_server->authserv_http_port;  
  12.     }  
  13. char *url = NULL;  
  14.     safe_asprintf(&url, "%s://%s:%d%s%s",  
  15.         protocol,  
  16.         auth_server->authserv_hostname,  
  17.         port,  
  18.         auth_server->authserv_path,  
  19.         urlFragment  
  20.     );  
  21.     http_send_redirect(r, url, text);  
  22.     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,布布扣,bubuko.com

wifidog 源码初分析(2)-转

标签:blog   code   http   ext   com   get   

原文地址:http://www.cnblogs.com/xmphoenix/p/3806834.html

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