wps_upnp_event.c
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00001 /*
00002  * UPnP WPS Device - Event processing
00003  * Copyright (c) 2000-2003 Intel Corporation
00004  * Copyright (c) 2006-2007 Sony Corporation
00005  * Copyright (c) 2008-2009 Atheros Communications
00006  * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
00007  *
00008  * See wps_upnp.c for more details on licensing and code history.
00009  */
00010 
00011 #include "includes.h"
00012 #include <assert.h>
00013 
00014 #include "common.h"
00015 #include "eloop.h"
00016 #include "uuid.h"
00017 #include "http_client.h"
00018 #include "wps_defs.h"
00019 #include "wps_upnp.h"
00020 #include "wps_upnp_i.h"
00021 
00022 /*
00023  * Event message generation (to subscribers)
00024  *
00025  * We make a separate copy for each message for each subscriber. This memory
00026  * wasted could be limited (adding code complexity) by sharing copies, keeping
00027  * a usage count and freeing when zero.
00028  *
00029  * Sending a message requires using a HTTP over TCP NOTIFY
00030  * (like a PUT) which requires a number of states..
00031  */
00032 
00033 #define MAX_EVENTS_QUEUED 20   /* How far behind queued events */
00034 #define EVENT_TIMEOUT_SEC 30   /* Drop sending event after timeout */
00035 
00036 /* How long to wait before sending event */
00037 #define EVENT_DELAY_SECONDS 0
00038 #define EVENT_DELAY_MSEC 0
00039 
00040 /*
00041  * Event information that we send to each subscriber is remembered in this
00042  * struct. The event cannot be sent by simple UDP; it has to be sent by a HTTP
00043  * over TCP transaction which requires various states.. It may also need to be
00044  * retried at a different address (if more than one is available).
00045  *
00046  * TODO: As an optimization we could share data between subscribers.
00047  */
00048 struct wps_event_ {
00049         struct dl_list list;
00050         struct subscription *s;         /* parent */
00051         unsigned subscriber_sequence;   /* which event for this subscription*/
00052         unsigned int retry;             /* which retry */
00053         struct subscr_addr *addr;       /* address to connect to */
00054         struct wpabuf *data;            /* event data to send */
00055         struct http_client *http_event;
00056 };
00057 
00058 
00059 /* event_clean -- clean sockets etc. of event
00060  * Leaves data, retry count etc. alone.
00061  */
00062 static void event_clean(struct wps_event_ *e)
00063 {
00064         if (e->s->current_event == e)
00065                 e->s->current_event = NULL;
00066         http_client_free(e->http_event);
00067         e->http_event = NULL;
00068 }
00069 
00070 
00071 /* event_delete -- delete single unqueued event
00072  * (be sure to dequeue first if need be)
00073  */
00074 static void event_delete(struct wps_event_ *e)
00075 {
00076         event_clean(e);
00077         wpabuf_free(e->data);
00078         os_free(e);
00079 }
00080 
00081 
00082 /* event_dequeue -- get next event from the queue
00083  * Returns NULL if empty.
00084  */
00085 static struct wps_event_ *event_dequeue(struct subscription *s)
00086 {
00087         struct wps_event_ *e;
00088         e = dl_list_first(&s->event_queue, struct wps_event_, list);
00089         if (e)
00090                 dl_list_del(&e->list);
00091         return e;
00092 }
00093 
00094 
00095 /* event_delete_all -- delete entire event queue and current event */
00096 void event_delete_all(struct subscription *s)
00097 {
00098         struct wps_event_ *e;
00099         while ((e = event_dequeue(s)) != NULL)
00100                 event_delete(e);
00101         if (s->current_event) {
00102                 event_delete(s->current_event);
00103                 /* will set: s->current_event = NULL;  */
00104         }
00105 }
00106 
00107 
00113 static void event_retry(struct wps_event_ *e, int do_next_address)
00114 {
00115         struct subscription *s = e->s;
00116         struct upnp_wps_device_sm *sm = s->sm;
00117 
00118         event_clean(e);
00119         /* will set: s->current_event = NULL; */
00120 
00121         if (do_next_address)
00122                 e->retry++;
00123         if (e->retry >= dl_list_len(&s->addr_list)) {
00124                 wpa_printf(MSG_DEBUG, "WPS UPnP: Giving up on sending event "
00125                            "for %s", e->addr->domain_and_port);
00126                 return;
00127         }
00128         dl_list_add(&s->event_queue, &e->list);
00129         event_send_all_later(sm);
00130 }
00131 
00132 
00133 static struct wpabuf * event_build_message(struct wps_event_ *e)
00134 {
00135         struct wpabuf *buf;
00136         char *b;
00137 
00138         buf = wpabuf_alloc(1000 + wpabuf_len(e->data));
00139         if (buf == NULL)
00140                 return NULL;
00141         wpabuf_printf(buf, "NOTIFY %s HTTP/1.1\r\n", e->addr->path);
00142         wpabuf_put_str(buf, "SERVER: Unspecified, UPnP/1.0, Unspecified\r\n");
00143         wpabuf_printf(buf, "HOST: %s\r\n", e->addr->domain_and_port);
00144         wpabuf_put_str(buf, "CONTENT-TYPE: text/xml; charset=\"utf-8\"\r\n"
00145                        "NT: upnp:event\r\n"
00146                        "NTS: upnp:propchange\r\n");
00147         wpabuf_put_str(buf, "SID: uuid:");
00148         b = wpabuf_put(buf, 0);
00149         uuid_bin2str(e->s->uuid, b, 80);
00150         wpabuf_put(buf, os_strlen(b));
00151         wpabuf_put_str(buf, "\r\n");
00152         wpabuf_printf(buf, "SEQ: %u\r\n", e->subscriber_sequence);
00153         wpabuf_printf(buf, "CONTENT-LENGTH: %d\r\n",
00154                       (int) wpabuf_len(e->data));
00155         wpabuf_put_str(buf, "\r\n"); /* terminating empty line */
00156         wpabuf_put_buf(buf, e->data);
00157         return buf;
00158 }
00159 
00160 
00161 static void event_http_cb(void *ctx, struct http_client *c,
00162                           enum http_client_event event)
00163 {
00164         struct wps_event_ *e = ctx;
00165         struct subscription *s = e->s;
00166 
00167         switch (event) {
00168         case HTTP_CLIENT_OK:
00169                 wpa_printf(MSG_DEBUG,
00170                            "WPS UPnP: Got event reply OK from "
00171                            "%s", e->addr->domain_and_port);
00172                 event_delete(e);
00173 
00174                 /* Schedule sending more if there is more to send */
00175                 if (!dl_list_empty(&s->event_queue))
00176                         event_send_all_later(s->sm);
00177                 break;
00178         case HTTP_CLIENT_FAILED:
00179         case HTTP_CLIENT_INVALID_REPLY:
00180                 wpa_printf(MSG_DEBUG, "WPS UPnP: Failed to send event to %s",
00181                            e->addr->domain_and_port);
00182 
00183                 /*
00184                  * If other side doesn't like what we say, forget about them.
00185                  * (There is no way to tell other side that we are dropping
00186                  * them...).
00187                  * Alternately, we could just do event_delete(e)
00188                  */
00189                 wpa_printf(MSG_DEBUG, "WPS UPnP: Deleting subscription due to "
00190                            "errors");
00191                 dl_list_del(&s->list);
00192                 subscription_destroy(s);
00193                 break;
00194         case HTTP_CLIENT_TIMEOUT:
00195                 wpa_printf(MSG_DEBUG, "WPS UPnP: Event send timeout");
00196                 event_retry(e, 1);
00197         }
00198 }
00199 
00200 
00201 /* event_send_start -- prepare to send a event message to subscriber
00202  *
00203  * This gets complicated because:
00204  * -- The message is sent via TCP and we have to keep the stream open
00205  *      for 30 seconds to get a response... then close it.
00206  * -- But we might have other event happen in the meantime...
00207  *      we have to queue them, if we lose them then the subscriber will
00208  *      be forced to unsubscribe and subscribe again.
00209  * -- If multiple URLs are provided then we are supposed to try successive
00210  *      ones after 30 second timeout.
00211  * -- The URLs might use domain names instead of dotted decimal addresses,
00212  *      and resolution of those may cause unwanted sleeping.
00213  * -- Doing the initial TCP connect can take a while, so we have to come
00214  *      back after connection and then send the data.
00215  *
00216  * Returns nonzero on error;
00217  *
00218  * Prerequisite: No current event send (s->current_event == NULL)
00219  *      and non-empty queue.
00220  */
00221 static int event_send_start(struct subscription *s)
00222 {
00223         struct wps_event_ *e;
00224         unsigned int itry;
00225         struct wpabuf *buf;
00226 
00227         /*
00228          * Assume we are called ONLY with no current event and ONLY with
00229          * nonempty event queue and ONLY with at least one address to send to.
00230          */
00231         assert(!dl_list_empty(&s->addr_list));
00232         assert(s->current_event == NULL);
00233         assert(!dl_list_empty(&s->event_queue));
00234 
00235         s->current_event = e = event_dequeue(s);
00236 
00237         /* Use address according to number of retries */
00238         itry = 0;
00239         dl_list_for_each(e->addr, &s->addr_list, struct subscr_addr, list)
00240                 if (itry++ == e->retry)
00241                         break;
00242         if (itry < e->retry)
00243                 return -1;
00244 
00245         buf = event_build_message(e);
00246         if (buf == NULL) {
00247                 event_retry(e, 0);
00248                 return -1;
00249         }
00250 
00251         e->http_event = http_client_addr(&e->addr->saddr, buf, 0,
00252                                          event_http_cb, e);
00253         if (e->http_event == NULL) {
00254                 wpabuf_free(buf);
00255                 event_retry(e, 0);
00256                 return -1;
00257         }
00258 
00259         return 0;
00260 }
00261 
00262 
00263 /* event_send_all_later_handler -- actually send events as needed */
00264 static void event_send_all_later_handler(void *eloop_data, void *user_ctx)
00265 {
00266         struct upnp_wps_device_sm *sm = user_ctx;
00267         struct subscription *s, *tmp;
00268         int nerrors = 0;
00269 
00270         sm->event_send_all_queued = 0;
00271         dl_list_for_each_safe(s, tmp, &sm->subscriptions, struct subscription,
00272                               list) {
00273                 if (dl_list_empty(&s->addr_list)) {
00274                         /* if we've given up on all addresses */
00275                         wpa_printf(MSG_DEBUG, "WPS UPnP: Removing "
00276                                    "subscription with no addresses");
00277                         dl_list_del(&s->list);
00278                         subscription_destroy(s);
00279                 } else {
00280                         if (s->current_event == NULL /* not busy */ &&
00281                             !dl_list_empty(&s->event_queue) /* more to do */) {
00282                                 if (event_send_start(s))
00283                                         nerrors++;
00284                         }
00285                 }
00286         }
00287 
00288         if (nerrors) {
00289                 /* Try again later */
00290                 event_send_all_later(sm);
00291         }
00292 }
00293 
00294 
00295 /* event_send_all_later -- schedule sending events to all subscribers
00296  * that need it.
00297  * This avoids two problems:
00298  * -- After getting a subscription, we should not send the first event
00299  *      until after our reply is fully queued to be sent back,
00300  * -- Possible stack depth or infinite recursion issues.
00301  */
00302 void event_send_all_later(struct upnp_wps_device_sm *sm)
00303 {
00304         /*
00305          * The exact time in the future isn't too important. Waiting a bit
00306          * might let us do several together.
00307          */
00308         if (sm->event_send_all_queued)
00309                 return;
00310         sm->event_send_all_queued = 1;
00311         eloop_register_timeout(EVENT_DELAY_SECONDS, EVENT_DELAY_MSEC,
00312                                event_send_all_later_handler, NULL, sm);
00313 }
00314 
00315 
00316 /* event_send_stop_all -- cleanup */
00317 void event_send_stop_all(struct upnp_wps_device_sm *sm)
00318 {
00319         if (sm->event_send_all_queued)
00320                 eloop_cancel_timeout(event_send_all_later_handler, NULL, sm);
00321         sm->event_send_all_queued = 0;
00322 }
00323 
00324 
00331 int event_add(struct subscription *s, const struct wpabuf *data)
00332 {
00333         struct wps_event_ *e;
00334 
00335         if (dl_list_len(&s->event_queue) >= MAX_EVENTS_QUEUED) {
00336                 wpa_printf(MSG_DEBUG, "WPS UPnP: Too many events queued for "
00337                            "subscriber");
00338                 return 1;
00339         }
00340 
00341         e = os_zalloc(sizeof(*e));
00342         if (e == NULL)
00343                 return 1;
00344         dl_list_init(&e->list);
00345         e->s = s;
00346         e->data = wpabuf_dup(data);
00347         if (e->data == NULL) {
00348                 os_free(e);
00349                 return 1;
00350         }
00351         e->subscriber_sequence = s->next_subscriber_sequence++;
00352         if (s->next_subscriber_sequence == 0)
00353                 s->next_subscriber_sequence++;
00354         dl_list_add_tail(&s->event_queue, &e->list);
00355         event_send_all_later(s->sm);
00356         return 0;
00357 }


wpa_supplicant_node
Author(s): Package maintained by Blaise Gassend
autogenerated on Thu Apr 24 2014 15:33:22