Hi,
I am curious, what is the use case for this API? Is there really
802.11 hardware that tracks its physical motion?
Henning Rogge
On Tue, Sep 9, 2014 at 3:07 PM, Emmanuel Grumbach
<emmanuel.grumbach@xxxxxxxxx> wrote:
> From: Avraham Stern <avraham.stern@xxxxxxxxx>
>
> Add API to notify user-space when the device is in motion
> and the motion type.
> This information can be used to react to the changing environment when
> the device is on the move, or avoid some unnecessary activities when
> the device is not moving. For example, longer scan intervals when the
> device is not moving and there are probably no new AP's, shorter scan
> intervals while the device is moving slowly and the environment is
> constantly changing, and not scanning at all when the device is moving
> fast and it is very unlikely to be able to connect to anything.
>
> Signed-off-by: Avraham Stern <avraham.stern@xxxxxxxxx>
> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
> ---
> include/net/cfg80211.h | 14 ++++++++
> include/uapi/linux/nl80211.h | 39 ++++++++++++++++++++++
> net/wireless/core.h | 2 ++
> net/wireless/nl80211.c | 78 ++++++++++++++++++++++++++++++++++++++++++++
> net/wireless/trace.h | 14 ++++++++
> 5 files changed, 147 insertions(+)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index b960c4d..6210822 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -4914,6 +4914,20 @@ void cfg80211_shutdown_all_interfaces(struct wiphy *wiphy);
> /* ethtool helper */
> void cfg80211_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info);
>
> +/*
> + * cfg80211_device_motion_notify - notify device motion type
> + *
> + * @wiphy: the wiphy
> + * @type: the motion type as specified in &enum nl80211_device_motion_type.
> + * @gfp: allocation flags
> + *
> + * This function is used to report to userspace the type of motion the device
> + * is currently in.
> + */
> +void cfg80211_device_motion_notify(struct wiphy *wiphy,
> + enum nl80211_device_motion_type type,
> + gfp_t gfp);
> +
> /* Logging, debugging and troubleshooting/diagnostic helpers. */
>
> /* wiphy_printk helpers, similar to dev_printk */
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index 8270024..fae01c7 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -733,6 +733,19 @@
> * QoS mapping is relevant for IP packets, it is only valid during an
> * association. This is cleared on disassociation and AP restart.
> *
> + * @NL80211_CMD_DEVICE_MOTION_NOTIFY: Device motion notification. This command
> + * is used as an event to indicate the motion type the device is currently
> + * in. This command can also be used by userspace to get the current
> + * motion type. The motion type is specified by the
> + * %NL80211_ATTR_DEVICE_MOTION_TYPE. This information can be used to react
> + * to the changing environment when the device is on the move, or avoid
> + * some unnecessary activities when the device is not moving. For example,
> + * longer scan intervals when the device is not moving and neighbor AP's
> + * probably stay the same, shorter scan intervals while the device is
> + * moving slowly and the environment is changing constantly, and not
> + * scanning at all when the device is moving fast and it is very unlikely
> + * to be able to connect to anything.
> + *
> * @NL80211_CMD_MAX: highest used command number
> * @__NL80211_CMD_AFTER_LAST: internal use
> */
> @@ -906,6 +919,8 @@ enum nl80211_commands {
>
> NL80211_CMD_CH_SWITCH_STARTED_NOTIFY,
>
> + NL80211_CMD_DEVICE_MOTION_NOTIFY,
> +
> /* add new commands above here */
>
> /* used to define NL80211_CMD_MAX below */
> @@ -1620,6 +1635,9 @@ enum nl80211_commands {
> * association request. In addition, it must also set the RRM capability
> * flag in the association request's Capability Info field.
> *
> + * @NL80211_ATTR_DEVICE_MOTION_TYPE: The type of motion the device is currently
> + * in. As specified in &enum nl80211_device_motion_type.
> + *
> * @NL80211_ATTR_MAX: highest attribute number currently defined
> * @__NL80211_ATTR_AFTER_LAST: internal use
> */
> @@ -1964,6 +1982,8 @@ enum nl80211_attrs {
>
> NL80211_ATTR_USE_RRM,
>
> + NL80211_ATTR_DEVICE_MOTION_TYPE,
> +
> /* add attributes here, update the policy in nl80211.c */
>
> __NL80211_ATTR_AFTER_LAST,
> @@ -4223,4 +4243,23 @@ enum nl80211_tdls_peer_capability {
> NL80211_TDLS_PEER_WMM = 1<<2,
> };
>
> +/**
> + * enum nl80211_device_motion_type - device motion types
> + * @NL80211_DEVICE_MOTION_TYPE_UNKNOWN: The device motion type is not known
> + * or has not been set yet.
> + * @NL80211_DEVICE_MOTION_TYPE_NOT_MOVING: The device is not moving. This
> + * includes cases in which the device is moving but its immediate
> + * environment is moving as well, e.g. while on board a train.
> + * @NL80211_DEVICE_MOTION_TYPE_MOVING_SLOWLY: The device is moving slowly enough
> + * to keep track of the changing environment.
> + * @NL80211_DEVICE_MOTION_TYPE_MOVING_FAST: The device is moving fast which
> + * makes it hard to keep track of the changing environment.
> + */
> +enum nl80211_device_motion_type {
> + NL80211_DEVICE_MOTION_TYPE_UNKNOWN,
> + NL80211_DEVICE_MOTION_TYPE_NOT_MOVING,
> + NL80211_DEVICE_MOTION_TYPE_MOVING_SLOWLY,
> + NL80211_DEVICE_MOTION_TYPE_MOVING_FAST,
> +};
> +
> #endif /* __LINUX_NL80211_H */
> diff --git a/net/wireless/core.h b/net/wireless/core.h
> index 21d4b1d..a00be85 100644
> --- a/net/wireless/core.h
> +++ b/net/wireless/core.h
> @@ -84,6 +84,8 @@ struct cfg80211_registered_device {
> struct list_head destroy_list;
> struct work_struct destroy_work;
>
> + enum nl80211_device_motion_type motion_type;
> +
> /* must be last because of the way we do wiphy_priv(),
> * and it should at least be aligned to NETDEV_ALIGN */
> struct wiphy wiphy __aligned(NETDEV_ALIGN);
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 03b5b5e..c7c014c 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -9451,6 +9451,48 @@ static int nl80211_set_qos_map(struct sk_buff *skb,
> return ret;
> }
>
> +static int nl80211_send_motion(struct sk_buff *msg, u32 portid, u32 seq,
> + int flags,
> + struct cfg80211_registered_device *rdev)
> +{
> + void *hdr;
> +
> + hdr = nl80211hdr_put(msg, portid, seq, flags,
> + NL80211_CMD_DEVICE_MOTION_NOTIFY);
> + if (!hdr)
> + return -ENOBUFS;
> +
> + if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
> + nla_put_u32(msg, NL80211_ATTR_DEVICE_MOTION_TYPE,
> + rdev->motion_type))
> + goto nla_put_failure;
> +
> + return genlmsg_end(msg, hdr);
> +
> + nla_put_failure:
> + genlmsg_cancel(msg, hdr);
> + return -ENOBUFS;
> +}
> +
> +static int nl80211_device_motion_notify(struct sk_buff *skb,
> + struct genl_info *info)
> +{
> + struct sk_buff *msg;
> + struct cfg80211_registered_device *rdev = info->user_ptr[0];
> +
> + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + if (nl80211_send_motion(msg, genl_info_snd_portid(info), info->snd_seq,
> + 0, rdev) < 0) {
> + nlmsg_free(msg);
> + return -ENOBUFS;
> + }
> +
> + return genlmsg_reply(msg, info);
> +}
> +
> #define NL80211_FLAG_NEED_WIPHY 0x01
> #define NL80211_FLAG_NEED_NETDEV 0x02
> #define NL80211_FLAG_NEED_RTNL 0x04
> @@ -10197,6 +10239,14 @@ static __genl_const struct genl_ops nl80211_ops[] = {
> .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
> NL80211_FLAG_NEED_RTNL,
> },
> + {
> + .cmd = NL80211_CMD_DEVICE_MOTION_NOTIFY,
> + .doit = nl80211_device_motion_notify,
> + .policy = nl80211_policy,
> + .flags = GENL_ADMIN_PERM,
> + .internal_flags = NL80211_FLAG_NEED_WIPHY |
> + NL80211_FLAG_NEED_RTNL,
> + },
> };
>
> /* notification functions */
> @@ -12004,6 +12054,34 @@ void cfg80211_crit_proto_stopped(struct wireless_dev *wdev, gfp_t gfp)
> }
> EXPORT_SYMBOL(cfg80211_crit_proto_stopped);
>
> +void cfg80211_device_motion_notify(struct wiphy *wiphy,
> + enum nl80211_device_motion_type type,
> + gfp_t gfp)
> +{
> + struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
> + struct sk_buff *msg;
> +
> + trace_cfg80211_device_motion_notify(wiphy, type);
> +
> + if (rdev->motion_type == type)
> + return;
> +
> + rdev->motion_type = type;
> +
> + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
> + if (!msg)
> + return;
> +
> + if (nl80211_send_motion(msg, 0, 0, 0, rdev) < 0) {
> + nlmsg_free(msg);
> + return;
> + }
> +
> + genlmsg_multicast_netns(&nl80211_fam, wiphy_net(wiphy), msg, 0,
> + NL80211_MCGRP_SCAN, gfp);
> +}
> +EXPORT_SYMBOL(cfg80211_device_motion_notify);
> +
> void nl80211_send_ap_stopped(struct wireless_dev *wdev)
> {
> struct wiphy *wiphy = wdev->wiphy;
> diff --git a/net/wireless/trace.h b/net/wireless/trace.h
> index 0f0901e..e39a950 100644
> --- a/net/wireless/trace.h
> +++ b/net/wireless/trace.h
> @@ -2627,6 +2627,20 @@ TRACE_EVENT(cfg80211_stop_iface,
> WIPHY_PR_ARG, WDEV_PR_ARG)
> );
>
> +TRACE_EVENT(cfg80211_device_motion_notify,
> + TP_PROTO(struct wiphy *wiphy, enum nl80211_device_motion_type type),
> + TP_ARGS(wiphy, type),
> + TP_STRUCT__entry(
> + WIPHY_ENTRY
> + __field(enum nl80211_device_motion_type, type)
> + ),
> + TP_fast_assign(
> + WIPHY_ASSIGN;
> + __entry->type = type;
> + ),
> + TP_printk(WIPHY_PR_FMT ", type: %d", WIPHY_PR_ARG, __entry->type)
> +);
> +
> #endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */
>
> #undef TRACE_INCLUDE_PATH
> --
> 1.9.1
>
> --
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