cfg80211/nl80211: add support for scheduled scans

Implement new functionality for scheduled scan offload.  With this feature we
can scan automatically at certain intervals.

The idea is that the hardware can perform scan automatically and filter on
desired results without waking up the host unnecessarily.

Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
commands to the nl80211 interface.  When results are available they are
reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
informed when the scheduled scan has stopped with a
NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 250 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 95dd5832e719..4fac370284c0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -761,6 +761,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
         }
         CMD(set_channel, SET_CHANNEL);
         CMD(set_wds_peer, SET_WDS_PEER);
+        if (dev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+                CMD(sched_scan_start, START_SCHED_SCAN);
 
 #undef CMD
 
@@ -3357,6 +3359,179 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
         return err;
 }
 
+static int nl80211_start_sched_scan(struct sk_buff *skb,
+                                    struct genl_info *info)
+{
+        struct cfg80211_sched_scan_request *request;
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct cfg80211_ssid *ssid;
+        struct ieee80211_channel *channel;
+        struct nlattr *attr;
+        struct wiphy *wiphy;
+        int err, tmp, n_ssids = 0, n_channels, i;
+        enum ieee80211_band band;
+        size_t ie_len;
+
+        if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
+            !rdev->ops->sched_scan_start)
+                return -EOPNOTSUPP;
+
+        if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
+                return -EINVAL;
+
+        if (rdev->sched_scan_req)
+                return -EINPROGRESS;
+
+        wiphy = &rdev->wiphy;
+
+        if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+                n_channels = validate_scan_freqs(
+                                info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]);
+                if (!n_channels)
+                        return -EINVAL;
+        } else {
+                n_channels = 0;
+
+                for (band = 0; band < IEEE80211_NUM_BANDS; band++)
+                        if (wiphy->bands[band])
+                                n_channels += wiphy->bands[band]->n_channels;
+        }
+
+        if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
+                nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS],
+                                    tmp)
+                        n_ssids++;
+
+        if (n_ssids > wiphy->max_scan_ssids)
+                return -EINVAL;
+
+        if (info->attrs[NL80211_ATTR_IE])
+                ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
+        else
+                ie_len = 0;
+
+        if (ie_len > wiphy->max_scan_ie_len)
+                return -EINVAL;
+
+        request = kzalloc(sizeof(*request)
+                        + sizeof(*ssid) * n_ssids
+                        + sizeof(channel) * n_channels
+                        + ie_len, GFP_KERNEL);
+        if (!request)
+                return -ENOMEM;
+
+        if (n_ssids)
+                request->ssids = (void *)&request->channels[n_channels];
+        request->n_ssids = n_ssids;
+        if (ie_len) {
+                if (request->ssids)
+                        request->ie = (void *)(request->ssids + n_ssids);
+                else
+                        request->ie = (void *)(request->channels + n_channels);
+        }
+
+        i = 0;
+        if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+                /* user specified, bail out if channel not found */
+                nla_for_each_nested(attr,
+                                    info->attrs[NL80211_ATTR_SCAN_FREQUENCIES],
+                                    tmp) {
+                        struct ieee80211_channel *chan;
+
+                        chan = ieee80211_get_channel(wiphy, nla_get_u32(attr));
+
+                        if (!chan) {
+                                err = -EINVAL;
+                                goto out_free;
+                        }
+
+                        /* ignore disabled channels */
+                        if (chan->flags & IEEE80211_CHAN_DISABLED)
+                                continue;
+
+                        request->channels[i] = chan;
+                        i++;
+                }
+        } else {
+                /* all channels */
+                for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+                        int j;
+                        if (!wiphy->bands[band])
+                                continue;
+                        for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
+                                struct ieee80211_channel *chan;
+
+                                chan = &wiphy->bands[band]->channels[j];
+
+                                if (chan->flags & IEEE80211_CHAN_DISABLED)
+                                        continue;
+
+                                request->channels[i] = chan;
+                                i++;
+                        }
+                }
+        }
+
+        if (!i) {
+                err = -EINVAL;
+                goto out_free;
+        }
+
+        request->n_channels = i;
+
+        i = 0;
+        if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {
+                nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS],
+                                    tmp) {
+                        if (request->ssids[i].ssid_len >
+                            IEEE80211_MAX_SSID_LEN) {
+                                err = -EINVAL;
+                                goto out_free;
+                        }
+                        memcpy(request->ssids[i].ssid, nla_data(attr),
+                               nla_len(attr));
+                        request->ssids[i].ssid_len = nla_len(attr);
+                        i++;
+                }
+        }
+
+        if (info->attrs[NL80211_ATTR_IE]) {
+                request->ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
+                memcpy((void *)request->ie,
+                       nla_data(info->attrs[NL80211_ATTR_IE]),
+                       request->ie_len);
+        }
+
+        request->dev = dev;
+        request->wiphy = &rdev->wiphy;
+
+        err = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
+        if (!err) {
+                rdev->sched_scan_req = request;
+                nl80211_send_sched_scan(rdev, dev,
+                                        NL80211_CMD_START_SCHED_SCAN);
+                goto out;
+        }
+
+out_free:
+        kfree(request);
+out:
+        return err;
+}
+
+static int nl80211_stop_sched_scan(struct sk_buff *skb,
+                                   struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+
+        if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
+            !rdev->ops->sched_scan_stop)
+                return -EOPNOTSUPP;
+
+        return __cfg80211_stop_sched_scan(rdev, false);
+}
+
 static int nl80211_send_bss(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                             struct cfg80211_registered_device *rdev,
                             struct wireless_dev *wdev,
@@ -5327,6 +5502,22 @@ static struct genl_ops nl80211_ops[] = {
                 .dumpit = nl80211_dump_scan,
         },
         {
+                .cmd = NL80211_CMD_START_SCHED_SCAN,
+                .doit = nl80211_start_sched_scan,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
+        {
+                .cmd = NL80211_CMD_STOP_SCHED_SCAN,
+                .doit = nl80211_stop_sched_scan,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
+        {
                 .cmd = NL80211_CMD_AUTHENTICATE,
                 .doit = nl80211_authenticate,
                 .policy = nl80211_policy,
@@ -5652,6 +5843,28 @@ static int nl80211_send_scan_msg(struct sk_buff *msg,
         return -EMSGSIZE;
 }
 
+static int
+nl80211_send_sched_scan_msg(struct sk_buff *msg,
+                            struct cfg80211_registered_device *rdev,
+                            struct net_device *netdev,
+                            u32 pid, u32 seq, int flags, u32 cmd)
+{
+        void *hdr;
+
+        hdr = nl80211hdr_put(msg, pid, seq, flags, cmd);
+        if (!hdr)
+                return -1;
+
+        NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+        NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+
+        return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        return -EMSGSIZE;
+}
+
 void nl80211_send_scan_start(struct cfg80211_registered_device *rdev,
                              struct net_device *netdev)
 {
@@ -5709,6 +5922,43 @@ void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
                                 nl80211_scan_mcgrp.id, GFP_KERNEL);
 }
 
+void nl80211_send_sched_scan_results(struct cfg80211_registered_device *rdev,
+                                     struct net_device *netdev)
+{
+        struct sk_buff *msg;
+
+        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+        if (!msg)
+                return;
+
+        if (nl80211_send_sched_scan_msg(msg, rdev, netdev, 0, 0, 0,
+                                        NL80211_CMD_SCHED_SCAN_RESULTS) < 0) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+                                nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
+void nl80211_send_sched_scan(struct cfg80211_registered_device *rdev,
+                             struct net_device *netdev, u32 cmd)
+{
+        struct sk_buff *msg;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                return;
+
+        if (nl80211_send_sched_scan_msg(msg, rdev, netdev, 0, 0, 0, cmd) < 0) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+                                nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
 /*
  * This can happen on global regulatory changes or device specific settings
  * based on custom world regulatory domains.