AOSP: P2P SD changes

This is rebased version (with couple of changes removed) of this AOSP
commit:

From f44b9c4a18d17fbd39901f76a014c32006570fb8 Mon Sep 17 00:00:00 2001
From: Irfan Sheriff <isheriff@google.com>
Date: Wed, 13 Jun 2012 11:09:23 -0700
Subject: [PATCH] Fix p2p service discovery

- Fix listen timing to improve SD reliability
- Fix SD packet scheduling

Bug: 6629112
Change-Id: I01365279439116256372d019bdbfd4b2113bf2ce

diff --git a/src/p2p/p2p.c b/src/p2p/p2p.c
index 178a8f6da92bb7163323c9ec52fe35debc83fc38..51205b884bfa5a0f49e8b11d653a140af3a680de 100644 (file)
--- a/src/p2p/p2p.c
+++ b/src/p2p/p2p.c
@@ -83,6 +83,12 @@ static void p2p_expire_peers(struct p2p_data *p2p)
 
                p2p_dbg(p2p, "Expiring old peer entry " MACSTR,
                        MAC2STR(dev->info.p2p_device_addr));
+
+#ifdef ANDROID_P2P
+               /* SD_FAIR_POLICY: Update the current sd_dev_list pointer to next device */
+               if(&dev->list == p2p->sd_dev_list)
+                       p2p->sd_dev_list = dev->list.next;
+#endif
                dl_list_del(&dev->list);
                p2p_device_free(p2p, dev);
        }
@@ -382,6 +388,11 @@ static struct p2p_device * p2p_create_device(struct p2p_data *p2p,
        }
        if (count + 1 > p2p->cfg->max_peers && oldest) {
                p2p_dbg(p2p, "Remove oldest peer entry to make room for a new peer");
+#ifdef ANDROID_P2P
+               /* SD_FAIR_POLICY: Update the current sd_dev_list pointer to next device */
+               if(&oldest->list == p2p->sd_dev_list)
+                       p2p->sd_dev_list = oldest->list.next;
+#endif
                dl_list_del(&oldest->list);
                p2p_device_free(p2p, oldest);
        }
@@ -923,7 +934,15 @@ static int p2p_run_after_scan(struct p2p_data *p2p)
                                      p2p->after_scan_tx->wait_time);
                os_free(p2p->after_scan_tx);
                p2p->after_scan_tx = NULL;
+#ifdef ANDROID_P2P
+               /* For SD frames, there is a scenario, where we can receive a SD request frame during p2p_scan.
+                * At that moment, we will send the SD response from this context. After sending the SD response,
+                * we need to continue p2p_find. But if we return 1 from here, p2p_find is going to be stopped.
+                */
+               return 0;
+#else
                return 1;
+#endif
        }
 
        op = p2p->start_after_scan;
@@ -2340,7 +2359,16 @@ struct p2p_data * p2p_init(const struct p2p_config *cfg)
                        p2p->cfg->num_pref_chan = 0;
        }
 
+#ifdef ANDROID_P2P
+       /* 100ms listen time is too less to receive the response frames in some scenarios
+        * increasing min listen time to 200ms.
+        */
+       p2p->min_disc_int = 2;
+       /* SD_FAIR_POLICY: Initializing the SD current serviced pointer to NULL */
+       p2p->sd_dev_list = NULL;
+#else
        p2p->min_disc_int = 1;
+#endif
        p2p->max_disc_int = 3;
        p2p->max_disc_tu = -1;
 
@@ -2410,6 +2438,10 @@ void p2p_flush(struct p2p_data *p2p)
                dl_list_del(&dev->list);
                p2p_device_free(p2p, dev);
        }
+#ifdef ANDROID_P2P
+       /* SD_FAIR_POLICY: Initializing the SD current serviced pointer to NULL */
+       p2p->sd_dev_list = NULL;
+#endif
        p2p_free_sd_queries(p2p);
        os_free(p2p->after_scan_tx);
        p2p->after_scan_tx = NULL;
@@ -2587,8 +2619,37 @@ int p2p_set_country(struct p2p_data *p2p, const char *country)
 void p2p_continue_find(struct p2p_data *p2p)
 {
        struct p2p_device *dev;
+#ifdef ANDROID_P2P
+       int skip=1;
+#endif
        p2p_set_state(p2p, P2P_SEARCH);
        dl_list_for_each(dev, &p2p->devices, struct p2p_device, list) {
+#ifdef ANDROID_P2P
+               /* SD_FAIR_POLICY: We need to give chance to all devices in the device list
+                * There may be a scenario, where a particular peer device have
+                * not registered any query response. When we send a SD request to such device,
+                * no response will be received. And if we continue to get probe responses from that device, 
+                * and if that device happens to be on top in our device list, 
+                * we will always continue to send SD requests always to that peer only. 
+                * We will not be able to send SD requests to other devices in that case. 
+                * This implementation keeps track of last serviced peer device. 
+                * And then takes the next one from the device list, in the next iteration.
+                */
+               if (p2p->sd_dev_list && p2p->sd_dev_list != &p2p->devices) {
+                       if(skip) {
+                               if ((&dev->list == p2p->sd_dev_list) ) {
+                                       skip = 0;
+                                       if (dev->list.next == &p2p->devices)
+                                               p2p->sd_dev_list = NULL;
+                               }
+                               continue;
+                       }
+               }
+               p2p->sd_dev_list = &dev->list;
+               wpa_printf(MSG_DEBUG, "P2P: ### Servicing %p dev->flags 0x%x SD schedule %s devaddr " MACSTR,
+                       p2p->sd_dev_list, dev->flags, dev->flags & P2P_DEV_SD_SCHEDULE ? "TRUE": "FALSE",
+                       MAC2STR(dev->info.p2p_device_addr));
+#endif
                if (dev->flags & P2P_DEV_SD_SCHEDULE) {
                        if (p2p_start_sd(p2p, dev) == 0)
                                return;

diff --git a/src/p2p/p2p_i.h b/src/p2p/p2p_i.h
index 6e57f45a8c4a02a9ba25768d25c822d1d9f316fa..d28aae934e1c54546dbde7ff34a05a02155cc610 100644 (file)
--- a/src/p2p/p2p_i.h
+++ b/src/p2p/p2p_i.h
@@ -237,6 +237,14 @@ struct p2p_data {
         */
        struct dl_list devices;
 
+#ifdef ANDROID_P2P
+       /**
+        * sd_dev_list - device pointer to be serviced next
+        * for service discovery
+        */
+       struct dl_list *sd_dev_list;
+#endif
+
        /**
         * go_neg_peer - Pointer to GO Negotiation peer
         */

diff --git a/src/p2p/p2p_sd.c b/src/p2p/p2p_sd.c
index 0e0c7f121e2f3b97943485a9225581bbe47a4ab8..ade93a28bef10df8f54cd21dae15d02f14b57272 100644 (file)
--- a/src/p2p/p2p_sd.c
+++ b/src/p2p/p2p_sd.c
@@ -819,6 +819,19 @@ void * p2p_sd_request(struct p2p_data *p2p, const u8 *dst,
                      const struct wpabuf *tlvs)
 {
        struct p2p_sd_query *q;
+#ifdef ANDROID_P2P
+       /* Currently, supplicant doesn't support more than one pending broadcast SD request.
+        * So reject if application is registering another one before cancelling the existing one.
+        */
+       for (q = p2p->sd_queries; q; q = q->next) {
+               if( (q->for_all_peers == 1) && (!dst)) {
+                               wpa_printf(MSG_ERROR, "P2P: Already one pending"
+                                       " Broadcast request. Please cancel the current one"
+                                       " before adding a new one");
+                               return NULL;
+               }
+       }
+#endif
 
        q = os_zalloc(sizeof(*q));
        if (q == NULL)