[RFC 4/4] P2P: Handling single channel concurrency

Jithu Jance jithujance at gmail.com
Mon Apr 9 07:30:11 EDT 2012


Hi Jouni,


> I applied the driver_nl80211.c part and below is a cleaned up version of
> the rest
Thanks!!

> Though, I did not go through all the details yet.
While testing, I found a bug in the patch I sent previously. In the
below piece of code, the "wpas_p2p_disconnect" call is not required as
wpas_p2p_group_delete is explicitly called with appropriate reason
code(FREQ_CONFLICT).
+               if (!wpas_is_p2p_prioritized(iface)) {
+                       /*
+                        * STA connection has priority over existing P2P
+                        * connection, so remove the interface.
+                        */
+                       wpas_p2p_disconnect(iface);
+                       iface->removal_reason =
+                               P2P_GROUP_REMOVAL_FREQ_CONFLICT;
+                       wpas_p2p_group_delete(iface);


I have generated a new patch including the above change. I am
attaching the patch and also putting it inline. Please see whether it
is fine.

[PATCH] P2P: Handle single channel concurrency

This patch handles cases where a STA connection is attempted after a P2P
connection and the new sta connection detects a freq conflict with the
existing P2P connection. Now based on the priority of the connection
(either sta or p2p), either one of the connection will be terminated.

Signed-hostap: Jithu Jance <jithu at broadcom.com>
---
 src/common/wpa_ctrl.h             |    2 +
 wpa_supplicant/p2p_supplicant.c   |   43 +++++++++++++++++++++++++++++++++++++
 wpa_supplicant/p2p_supplicant.h   |    2 +
 wpa_supplicant/wpa_supplicant.c   |   22 +++++++++++++++++++
 wpa_supplicant/wpa_supplicant_i.h |    3 +-
 5 files changed, 71 insertions(+), 1 deletions(-)

diff --git a/src/common/wpa_ctrl.h b/src/common/wpa_ctrl.h
index 35012e8..2e35e9c 100644
--- a/src/common/wpa_ctrl.h
+++ b/src/common/wpa_ctrl.h
@@ -56,6 +56,8 @@ extern "C" {
 #define WPA_EVENT_BSS_ADDED "CTRL-EVENT-BSS-ADDED "
 /** A BSS entry was removed (followed by BSS entry id and BSSID) */
 #define WPA_EVENT_BSS_REMOVED "CTRL-EVENT-BSS-REMOVED "
+/** Notify the Userspace about the freq conflict */
+#define WPA_EVENT_FREQ_CONFLICT "CTRL-EVENT-FREQ-CONFLICT "

 /** WPS overlap detected in PBC mode */
 #define WPS_EVENT_OVERLAP "WPS-OVERLAP-DETECTED "
diff --git a/wpa_supplicant/p2p_supplicant.c b/wpa_supplicant/p2p_supplicant.c
index 9d31fdb..62a5ae5 100644
--- a/wpa_supplicant/p2p_supplicant.c
+++ b/wpa_supplicant/p2p_supplicant.c
@@ -258,6 +258,9 @@ static void wpas_p2p_group_delete(struct
wpa_supplicant *wpa_s)
       case P2P_GROUP_REMOVAL_GO_ENDING_SESSION:
               reason = " reason=GO_ENDING_SESSION";
               break;
+       case P2P_GROUP_REMOVAL_FREQ_CONFLICT:
+               reason = " reason=FREQ_CONFLICT";
+               break;
       default:
               reason = "";
               break;
@@ -4609,3 +4612,43 @@ void wpas_p2p_notify_ap_sta_authorized(struct
wpa_supplicant *wpa_s,
               return;
       wpas_p2p_add_persistent_group_client(wpa_s, addr);
 }
+
+int wpas_p2p_handle_frequency_conflicts(struct wpa_supplicant *wpa_s, int freq)
+{
+       struct wpa_supplicant *iface = NULL;
+
+       for (iface = wpa_s->global->ifaces; iface; iface = iface->next) {
+               if((iface->p2p_group_interface) && (iface->current_ssid) &&
+                       (iface->current_ssid->frequency != freq)) {
+
+                       if (iface->p2p_group_interface ==
P2P_GROUP_INTERFACE_GO) {
+                                       /* Try to see whether we can
move the GO. If it
+                                        * is not possible, remove the
GO interface
+                                        */
+
if(wpa_drv_switch_channel(iface, freq) == 0) {
+
wpa_printf(MSG_ERROR, "P2P: GO Moved to freq(%d)", freq);
+
iface->current_ssid->frequency = freq;
+                                                       continue;
+                                       }
+                       }
+
+                       /* If GO cannot be moved or if the conflicting
interface is a
+                        * P2P Client, remove the interface depending
up on the connection
+                        * priority */
+                       if(!wpas_is_p2p_prioritized(wpa_s)) {
+                               /* STA connection has priority over existing
+                                * P2P connection. So remove the interface */
+                               wpa_printf(MSG_DEBUG, "P2P: Removing
P2P connection due to Single channel"
+                                               "concurrent mode
frequency conflict");
+                               iface->removal_reason =
P2P_GROUP_REMOVAL_FREQ_CONFLICT;
+                               wpas_p2p_group_delete(iface);
+                       } else {
+                               /* Existing connection has the
priority. Disable the newly
+                                * selected network and let the
application know about it.
+                                */
+                               return -1;
+                       }
+               }
+       }
+       return 0;
+}
diff --git a/wpa_supplicant/p2p_supplicant.h b/wpa_supplicant/p2p_supplicant.h
index 8f8e635..2cddc40 100644
--- a/wpa_supplicant/p2p_supplicant.h
+++ b/wpa_supplicant/p2p_supplicant.h
@@ -25,6 +25,8 @@ void wpas_p2p_remain_on_channel_cb(struct
wpa_supplicant *wpa_s,
                                  unsigned int freq, unsigned int duration);
 void wpas_p2p_cancel_remain_on_channel_cb(struct wpa_supplicant *wpa_s,
                                         unsigned int freq);
+int wpas_p2p_handle_frequency_conflicts(struct wpa_supplicant *wpa_s,
+                                          int freq);
 int wpas_p2p_group_remove(struct wpa_supplicant *wpa_s, const char *ifname);
 int wpas_p2p_group_add(struct wpa_supplicant *wpa_s, int persistent_group,
                      int freq);
diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
index c5a7115..61678e0 100644
--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -1100,6 +1100,7 @@ void wpa_supplicant_associate(struct
wpa_supplicant *wpa_s,
       ibss_rsn_deinit(wpa_s->ibss_rsn);
       wpa_s->ibss_rsn = NULL;
 #endif /* CONFIG_IBSS_RSN */
+       int freq = 0;

       if (ssid->mode == WPAS_MODE_AP || ssid->mode == WPAS_MODE_P2P_GO ||
           ssid->mode == WPAS_MODE_P2P_GROUP_FORMATION) {
@@ -1404,6 +1405,27 @@ void wpa_supplicant_associate(struct
wpa_supplicant *wpa_s,
       wpa_supplicant_apply_ht_overrides(wpa_s, ssid, &params);
 #endif /* CONFIG_HT_OVERRIDES */

+       /* If multichannel concurrency is not supported, check for any frequency
+        * conflict and take appropriate action.
+        */
+       if (!(wpa_s->drv_flags & WPA_DRIVER_FLAGS_MULTI_CHANNEL_CONCURRENT) &&
+               ((freq = wpa_drv_shared_freq(wpa_s)) > 0) && (freq !=
params.freq)) {
+               wpa_printf(MSG_DEBUG, "Shared interface with
conflicting frequency
found (%d != %d)",
+                               freq, params.freq);
+#ifdef CONFIG_P2P
+               if (wpas_p2p_handle_frequency_conflicts(wpa_s,
params.freq) < 0) {
+                       /* Handling conflicts failed. Disable the
current connect req and
+                        * notify the userspace to take appropriate action */
+                       wpa_printf(MSG_DEBUG, "proiritize is not set.
Notifying user space
to handle the case");
+                       wpa_supplicant_disable_network(wpa_s, ssid);
+                       wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_FREQ_CONFLICT
+                               " id=%d", ssid->id);
+                       os_memset(wpa_s->pending_bssid, 0, ETH_ALEN);
+                       return;
+               }
+#endif /* CONFIG_P2P */
+       }
+
       ret = wpa_drv_associate(wpa_s, &params);
       if (ret < 0) {
               wpa_msg(wpa_s, MSG_INFO, "Association request to the driver "
diff --git a/wpa_supplicant/wpa_supplicant_i.h
b/wpa_supplicant/wpa_supplicant_i.h
index a494c49..984ca52 100644
--- a/wpa_supplicant/wpa_supplicant_i.h
+++ b/wpa_supplicant/wpa_supplicant_i.h
@@ -504,7 +504,8 @@ struct wpa_supplicant {
               P2P_GROUP_REMOVAL_REQUESTED,
               P2P_GROUP_REMOVAL_IDLE_TIMEOUT,
               P2P_GROUP_REMOVAL_UNAVAILABLE,
-               P2P_GROUP_REMOVAL_GO_ENDING_SESSION
+               P2P_GROUP_REMOVAL_GO_ENDING_SESSION,
+               P2P_GROUP_REMOVAL_FREQ_CONFLICT
       } removal_reason;

       unsigned int p2p_cb_on_scan_complete:1;
--
1.7.4.1




- Jithu Jance










On Mon, Apr 9, 2012 at 12:08 AM, Jouni Malinen <j at w1.fi> wrote:
>
> On Tue, Mar 06, 2012 at 10:34:38AM +0530, Jithu Jance wrote:
> > This patch handles cases where a STA connection is attempted after a P2P
> > connection and the new sta connection detects a freq
> > conflict with the existing P2P connection. Now based on the priority of the
> > connection (either sta or p2p), either one of the connection
> > will be terminated.
>
> I applied the driver_nl80211.c part and below is a cleaned up version of
> the rest. Though, I did not go through all the details yet.
>
>
> [PATCH 3/3] P2P: Handle single channel concurrency
>
> This patch handles cases where a STA connection is attempted after a P2P
> connection and the new sta connection detects a freq conflict with the
> existing P2P connection. Now based on the priority of the connection
> (either sta or p2p), either one of the connection will be terminated.
>
> Signed-hostap: Jithu Jance <jithu at broadcom.com>
> ---
>  src/common/wpa_ctrl.h             |    2 +
>  wpa_supplicant/p2p_supplicant.c   |   50 +++++++++++++++++++++++++++++++++++++
>  wpa_supplicant/p2p_supplicant.h   |    2 +
>  wpa_supplicant/wpa_supplicant.c   |   27 ++++++++++++++++++++
>  wpa_supplicant/wpa_supplicant_i.h |    3 +-
>  5 files changed, 83 insertions(+), 1 deletions(-)
>
> diff --git a/src/common/wpa_ctrl.h b/src/common/wpa_ctrl.h
> index 35012e8..2e35e9c 100644
> --- a/src/common/wpa_ctrl.h
> +++ b/src/common/wpa_ctrl.h
> @@ -56,6 +56,8 @@ extern "C" {
>  #define WPA_EVENT_BSS_ADDED "CTRL-EVENT-BSS-ADDED "
>  /** A BSS entry was removed (followed by BSS entry id and BSSID) */
>  #define WPA_EVENT_BSS_REMOVED "CTRL-EVENT-BSS-REMOVED "
> +/** Notify the Userspace about the freq conflict */
> +#define WPA_EVENT_FREQ_CONFLICT "CTRL-EVENT-FREQ-CONFLICT "
>
>  /** WPS overlap detected in PBC mode */
>  #define WPS_EVENT_OVERLAP "WPS-OVERLAP-DETECTED "
> diff --git a/wpa_supplicant/p2p_supplicant.c b/wpa_supplicant/p2p_supplicant.c
> index 9d31fdb..3abcee7 100644
> --- a/wpa_supplicant/p2p_supplicant.c
> +++ b/wpa_supplicant/p2p_supplicant.c
> @@ -4609,3 +4609,53 @@ void wpas_p2p_notify_ap_sta_authorized(struct wpa_supplicant *wpa_s,
>                return;
>        wpas_p2p_add_persistent_group_client(wpa_s, addr);
>  }
> +
> +
> +int wpas_p2p_handle_frequency_conflicts(struct wpa_supplicant *wpa_s, int freq)
> +{
> +       struct wpa_supplicant *iface;
> +
> +       for (iface = wpa_s->global->ifaces; iface; iface = iface->next) {
> +               if (!iface->p2p_group_interface || !iface->current_ssid ||
> +                   iface->current_ssid->frequency == freq)
> +                       continue;
> +
> +               if (iface->p2p_group_interface == P2P_GROUP_INTERFACE_GO) {
> +                       /*
> +                        * Try to see whether we can move the GO. If it is not
> +                        * possible, remove the GO interface.
> +                        */
> +                       if (wpa_drv_switch_channel(iface, freq) == 0) {
> +                               wpa_printf(MSG_INFO, "P2P: GO Moved to freq "
> +                                          "%d MHz", freq);
> +                               iface->current_ssid->frequency = freq;
> +                               continue;
> +                       }
> +               }
> +
> +               /*
> +                * If GO cannot be moved or if the conflicting interface is a
> +                * P2P Client, remove the interface depending up on the
> +                * connection priority.
> +                */
> +               if (!wpas_is_p2p_prioritized(iface)) {
> +                       /*
> +                        * STA connection has priority over existing P2P
> +                        * connection, so remove the interface.
> +                        */
> +                       wpas_p2p_disconnect(iface);
> +                       iface->removal_reason =
> +                               P2P_GROUP_REMOVAL_FREQ_CONFLICT;
> +                       wpas_p2p_group_delete(iface);
> +               } else {
> +                       /*
> +                        * Existing connection has the priority. Disable the
> +                        * newly selected network and let the application know
> +                        * about it.
> +                        */
> +                       return -1;
> +               }
> +       }
> +
> +       return 0;
> +}
> diff --git a/wpa_supplicant/p2p_supplicant.h b/wpa_supplicant/p2p_supplicant.h
> index 8f8e635..fb0522b 100644
> --- a/wpa_supplicant/p2p_supplicant.h
> +++ b/wpa_supplicant/p2p_supplicant.h
> @@ -25,6 +25,8 @@ void wpas_p2p_remain_on_channel_cb(struct wpa_supplicant *wpa_s,
>                                   unsigned int freq, unsigned int duration);
>  void wpas_p2p_cancel_remain_on_channel_cb(struct wpa_supplicant *wpa_s,
>                                          unsigned int freq);
> +int wpas_p2p_handle_frequency_conflicts(struct wpa_supplicant *wpa_s,
> +                                       int freq);
>  int wpas_p2p_group_remove(struct wpa_supplicant *wpa_s, const char *ifname);
>  int wpas_p2p_group_add(struct wpa_supplicant *wpa_s, int persistent_group,
>                       int freq);
> diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
> index 1c88949..7b4e178 100644
> --- a/wpa_supplicant/wpa_supplicant.c
> +++ b/wpa_supplicant/wpa_supplicant.c
> @@ -1091,6 +1091,7 @@ void wpa_supplicant_associate(struct wpa_supplicant *wpa_s,
>        struct wpa_driver_capa capa;
>        int assoc_failed = 0;
>        struct wpa_ssid *old_ssid;
> +       int freq;
>  #ifdef CONFIG_HT_OVERRIDES
>        struct ieee80211_ht_capabilities htcaps;
>        struct ieee80211_ht_capabilities htcaps_mask;
> @@ -1404,6 +1405,32 @@ void wpa_supplicant_associate(struct wpa_supplicant *wpa_s,
>        wpa_supplicant_apply_ht_overrides(wpa_s, ssid, &params);
>  #endif /* CONFIG_HT_OVERRIDES */
>
> +       /*
> +        * If multichannel concurrency is not supported, check for any
> +        * frequency conflict and take appropriate action.
> +        */
> +       if (!(wpa_s->drv_flags & WPA_DRIVER_FLAGS_MULTI_CHANNEL_CONCURRENT) &&
> +           ((freq = wpa_drv_shared_freq(wpa_s)) > 0) && freq != params.freq) {
> +               wpa_printf(MSG_DEBUG, "Shared interface with conflicting "
> +                          "frequency found (%d != %d)", freq, params.freq);
> +#ifdef CONFIG_P2P
> +               if (wpas_p2p_handle_frequency_conflicts(wpa_s, params.freq) <
> +                   0) {
> +                       /*
> +                        * Handling conflicts failed. Disable the current
> +                        * connect req and notify the userspace to take
> +                        * appropriate action.
> +                        */
> +                       wpa_printf(MSG_DEBUG, "prioritize is not set. "
> +                                  "Notifying user space to handle the case.");
> +                       wpa_supplicant_disable_network(wpa_s, ssid);
> +                       wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_FREQ_CONFLICT
> +                               " id=%d", ssid->id);
> +                       os_memset(wpa_s->pending_bssid, 0, ETH_ALEN);
> +               }
> +#endif /* CONFIG_P2P */
> +       }
> +
>        ret = wpa_drv_associate(wpa_s, &params);
>        if (ret < 0) {
>                wpa_msg(wpa_s, MSG_INFO, "Association request to the driver "
> diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
> index 3f1f589..3c86857 100644
> --- a/wpa_supplicant/wpa_supplicant_i.h
> +++ b/wpa_supplicant/wpa_supplicant_i.h
> @@ -509,7 +509,8 @@ struct wpa_supplicant {
>                P2P_GROUP_REMOVAL_REQUESTED,
>                P2P_GROUP_REMOVAL_IDLE_TIMEOUT,
>                P2P_GROUP_REMOVAL_UNAVAILABLE,
> -               P2P_GROUP_REMOVAL_GO_ENDING_SESSION
> +               P2P_GROUP_REMOVAL_GO_ENDING_SESSION,
> +               P2P_GROUP_REMOVAL_FREQ_CONFLICT
>        } removal_reason;
>
>        unsigned int p2p_cb_on_scan_complete:1;
> --
> 1.7.4.1
>
>
> --
> Jouni Malinen                                            PGP id EFC895FA
> _______________________________________________
> HostAP mailing list
> HostAP at lists.shmoo.com
> http://lists.shmoo.com/mailman/listinfo/hostap


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