To allow channel switch announcements within beacons, add
the channel switch command to nl80211/cfg80211. This is
implementation is intended for AP and (later) IBSS mode.
Signed-off-by: Simon Wunderlich <siwu@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@xxxxxxxxxxxxxxxxxxx>
---
Changes to PATCHv4:
* add tracing
* rename csa_ies to csa_attrs
Changes to PATCHv2:
* define csa_ies as static to save stack size
* add wiphy flag and cmd for channel_switch
* move NL80211_ATTR_CSA_C_OFF_BEACON into csa_ies
Changes to RFCv1:
* accept and pass CSA IEs and after-change IEs
* use parameter structure instead of individual parameters
---
include/net/cfg80211.h | 30 ++++++++++
include/uapi/linux/nl80211.h | 29 ++++++++++
net/wireless/nl80211.c | 124 +++++++++++++++++++++++++++++++++++++++++-
net/wireless/rdev-ops.h | 12 ++++
net/wireless/trace.h | 33 +++++++++++
5 files changed, 227 insertions(+), 1 deletion(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index aeaf6df..9aa7918 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -666,6 +666,30 @@ struct cfg80211_ap_settings {
};
/**
+ * struct cfg80211_csa_settings - channel switch settings
+ *
+ * Used for channel switch
+ *
+ * @chandef: defines the channel to use after the switch
+ * @beacon_csa: beacon data while performing the switch
+ * @counter_offset_beacon: offset for the counter within the beacon (tail)
+ * @counter_offset_presp: offset for the counter within the probe response
+ * @beacon_after: beacon data to be used on the new channel
+ * @radar_required: whether radar detection is required on the new channel
+ * @block_tx: whether transmissions should be blocked while changing
+ * @count: number of beacons until switch
+ */
+struct cfg80211_csa_settings {
+ struct cfg80211_chan_def chandef;
+ struct cfg80211_beacon_data beacon_csa;
+ u16 counter_offset_beacon, counter_offset_presp;
+ struct cfg80211_beacon_data beacon_after;
+ bool radar_required;
+ bool block_tx;
+ u8 count;
+};
+
+/**
* enum station_parameters_apply_mask - station parameter values to apply
* @STATION_PARAM_APPLY_UAPSD: apply new uAPSD parameters (uapsd_queues, max_sp)
* @STATION_PARAM_APPLY_CAPABILITY: apply new capability
@@ -2376,6 +2400,9 @@ struct cfg80211_ops {
struct wireless_dev *wdev);
int (*set_coalesce)(struct wiphy *wiphy,
struct cfg80211_coalesce *coalesce);
+ int (*channel_switch)(struct wiphy *wiphy,
+ struct net_device *dev,
+ struct cfg80211_csa_settings *params);
};
/*
@@ -2441,6 +2468,8 @@ struct cfg80211_ops {
* @WIPHY_FLAG_OFFCHAN_TX: Device supports direct off-channel TX.
* @WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL: Device supports remain-on-channel call.
* @WIPHY_FLAG_SUPPORTS_5_10_MHZ: Device supports 5 MHz and 10 MHz channels.
+ * @WIPHY_FLAG_HAS_CHANNEL_SWITCH: Device supports channel switch in
+ * beaconing mode (AP, IBSS, Mesh, ...).
*/
enum wiphy_flags {
WIPHY_FLAG_CUSTOM_REGULATORY = BIT(0),
@@ -2465,6 +2494,7 @@ enum wiphy_flags {
WIPHY_FLAG_OFFCHAN_TX = BIT(20),
WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL = BIT(21),
WIPHY_FLAG_SUPPORTS_5_10_MHZ = BIT(22),
+ WIPHY_FLAG_HAS_CHANNEL_SWITCH = BIT(23),
};
/**
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index eb68735..8d07ee0 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -676,6 +676,16 @@
* @NL80211_CMD_GET_COALESCE: Get currently supported coalesce rules.
* @NL80211_CMD_SET_COALESCE: Configure coalesce rules or clear existing rules.
*
+ * @NL80211_CMD_CHANNEL_SWITCH: Perform a channel switch by announcing the
+ * the new channel information (Channel Switch Announcement - CSA)
+ * in the beacon for some time (as defined in the
+ * %NL80211_ATTR_CH_SWITCH_COUNT parameter) and then change to the
+ * new channel. Userspace provides the new channel information (using
+ * %NL80211_ATTR_WIPHY_FREQ and the attributes determining channel
+ * width). %NL80211_ATTR_CH_SWITCH_BLOCK_TX may be supplied to inform
+ * other station that transmission must be blocked until the channel
+ * switch is complete.
+ *
* @NL80211_CMD_MAX: highest used command number
* @__NL80211_CMD_AFTER_LAST: internal use
*/
@@ -841,6 +851,7 @@ enum nl80211_commands {
NL80211_CMD_GET_COALESCE,
NL80211_CMD_SET_COALESCE,
+ NL80211_CMD_CHANNEL_SWITCH,
/* add new commands above here */
/* used to define NL80211_CMD_MAX below */
@@ -1469,6 +1480,18 @@ enum nl80211_commands {
*
* @NL80211_ATTR_COALESCE_RULE: Coalesce rule information.
*
+ * @NL80211_ATTR_CH_SWITCH_COUNT: u32 attribute specifying the number of TBTT's
+ * until the channel switch event.
+ * @NL80211_ATTR_CH_SWITCH_BLOCK_TX: flag attribute specifying that transmission
+ * must be blocked on the current channel (before the channel switch
+ * operation).
+ * @NL80211_ATTR_CSA_IES: Nested set of attributes containing the IE information
+ * for the time while performing a channel switch.
+ * @NL80211_ATTR_CSA_C_OFF_BEACON: Offset of the channel switch counter
+ * field in the beacons tail (%NL80211_ATTR_BEACON_TAIL).
+ * @NL80211_ATTR_CSA_C_OFF_PRESP: Offset of the channel switch counter
+ * field in the probe response (%NL80211_ATTR_PROBE_RESP).
+ *
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
*/
@@ -1771,6 +1794,12 @@ enum nl80211_attrs {
NL80211_ATTR_COALESCE_RULE,
+ NL80211_ATTR_CH_SWITCH_COUNT,
+ NL80211_ATTR_CH_SWITCH_BLOCK_TX,
+ NL80211_ATTR_CSA_IES,
+ NL80211_ATTR_CSA_C_OFF_BEACON,
+ NL80211_ATTR_CSA_C_OFF_PRESP,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index a9444cd..f08b058 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -349,6 +349,11 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
[NL80211_ATTR_IE_RIC] = { .type = NLA_BINARY,
.len = IEEE80211_MAX_DATA_LEN },
[NL80211_ATTR_PEER_AID] = { .type = NLA_U16 },
+ [NL80211_ATTR_CH_SWITCH_COUNT] = { .type = NLA_U32 },
+ [NL80211_ATTR_CH_SWITCH_BLOCK_TX] = { .type = NLA_FLAG },
+ [NL80211_ATTR_CSA_IES] = { .type = NLA_NESTED },
+ [NL80211_ATTR_CSA_C_OFF_BEACON] = { .type = NLA_U16 },
+ [NL80211_ATTR_CSA_C_OFF_PRESP] = { .type = NLA_U16 },
};
/* policy for the key attributes */
@@ -1422,6 +1427,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev,
if (state->split) {
CMD(crit_proto_start, CRIT_PROTOCOL_START);
CMD(crit_proto_stop, CRIT_PROTOCOL_STOP);
+ if (dev->wiphy.flags & WIPHY_FLAG_HAS_CHANNEL_SWITCH)
+ CMD(channel_switch, CHANNEL_SWITCH);
}
#ifdef CONFIG_NL80211_TESTMODE
@@ -5611,6 +5618,113 @@ static int nl80211_start_radar_detection(struct sk_buff *skb,
return err;
}
+static int nl80211_channel_switch(struct sk_buff *skb,
+ struct genl_info *info)
+{
+ struct cfg80211_registered_device *rdev = info->user_ptr[0];
+ struct net_device *dev = info->user_ptr[1];
+ struct wireless_dev *wdev = dev->ieee80211_ptr;
+ struct cfg80211_csa_settings params;
+ /* csa_attrs is defined static to avoid waste of stack size - this
+ * function is called under RTNL lock, so this should not be a problem.
+ */
+ static struct nlattr *csa_attrs[NL80211_ATTR_MAX+1];
+ u8 radar_detect_width = 0;
+ int err;
+
+ if (!rdev->ops->channel_switch ||
+ !(rdev->wiphy.flags & WIPHY_FLAG_HAS_CHANNEL_SWITCH))
+ return -EOPNOTSUPP;
+
+ /* may add IBSS support later */
+ if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
+ dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
+ return -EOPNOTSUPP;
+
+ memset(¶ms, 0, sizeof(params));
+
+ if (!info->attrs[NL80211_ATTR_WIPHY_FREQ] ||
+ !info->attrs[NL80211_ATTR_CH_SWITCH_COUNT])
+ return -EINVAL;
+
+ /* only important for AP, IBSS and mesh create IEs internally */
+ if (!info->attrs[NL80211_ATTR_CSA_IES])
+ return -EINVAL;
+
+ /* useless if AP is not running */
+ if (!wdev->beacon_interval)
+ return -EINVAL;
+
+ params.count = nla_get_u32(info->attrs[NL80211_ATTR_CH_SWITCH_COUNT]);
+
+ err = nl80211_parse_beacon(info->attrs, ¶ms.beacon_after);
+ if (err)
+ return err;
+
+ err = nla_parse_nested(csa_attrs, NL80211_ATTR_MAX,
+ info->attrs[NL80211_ATTR_CSA_IES],
+ nl80211_policy);
+ if (err)
+ return err;
+
+ err = nl80211_parse_beacon(csa_attrs, ¶ms.beacon_csa);
+ if (err)
+ return err;
+
+ if (!csa_attrs[NL80211_ATTR_CSA_C_OFF_BEACON])
+ return -EINVAL;
+
+ params.counter_offset_beacon =
+ nla_get_u16(csa_attrs[NL80211_ATTR_CSA_C_OFF_BEACON]);
+ if (params.counter_offset_beacon > params.beacon_csa.tail_len)
+ return -EINVAL;
+
+ /* sanity check - counters should be the same */
+ if (params.beacon_csa.tail[params.counter_offset_beacon] !=
+ params.count)
+ return -EINVAL;
+
+ if (csa_attrs[NL80211_ATTR_CSA_C_OFF_PRESP]) {
+ params.counter_offset_presp =
+ nla_get_u16(csa_attrs[NL80211_ATTR_CSA_C_OFF_PRESP]);
+ if (params.counter_offset_presp >
+ params.beacon_csa.probe_resp_len)
+ return -EINVAL;
+
+ if (params.beacon_csa.probe_resp[params.counter_offset_presp] !=
+ params.count)
+ return -EINVAL;
+ }
+
+ err = nl80211_parse_chandef(rdev, info, ¶ms.chandef);
+ if (err)
+ return err;
+
+ if (!cfg80211_reg_can_beacon(&rdev->wiphy, ¶ms.chandef))
+ return -EINVAL;
+
+ err = cfg80211_chandef_dfs_required(wdev->wiphy, ¶ms.chandef);
+ if (err < 0)
+ return err;
+
+ if (err)
+ radar_detect_width = BIT(params.chandef.width);
+ else
+ radar_detect_width = 0;
+
+ err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+ params.chandef.chan,
+ CHAN_MODE_SHARED,
+ radar_detect_width);
+ if (err)
+ return err;
+
+ if (info->attrs[NL80211_ATTR_CH_SWITCH_BLOCK_TX])
+ params.block_tx = true;
+
+ return rdev_channel_switch(rdev, dev, ¶ms);
+}
+
static int nl80211_send_bss(struct sk_buff *msg, struct netlink_callback *cb,
u32 seq, int flags,
struct cfg80211_registered_device *rdev,
@@ -9359,7 +9473,15 @@ static struct genl_ops nl80211_ops[] = {
.flags = GENL_ADMIN_PERM,
.internal_flags = NL80211_FLAG_NEED_WIPHY |
NL80211_FLAG_NEED_RTNL,
- }
+ },
+ {
+ .cmd = NL80211_CMD_CHANNEL_SWITCH,
+ .doit = nl80211_channel_switch,
+ .policy = nl80211_policy,
+ .flags = GENL_ADMIN_PERM,
+ .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+ NL80211_FLAG_NEED_RTNL,
+ },
};
static struct genl_multicast_group nl80211_mlme_mcgrp = {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 9f15f0a..de870d4 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -923,4 +923,16 @@ static inline void rdev_crit_proto_stop(struct cfg80211_registered_device *rdev,
trace_rdev_return_void(&rdev->wiphy);
}
+static inline int rdev_channel_switch(struct cfg80211_registered_device *rdev,
+ struct net_device *dev,
+ struct cfg80211_csa_settings *params)
+{
+ int ret;
+
+ trace_rdev_channel_switch(&rdev->wiphy, dev, params);
+ ret = rdev->ops->channel_switch(&rdev->wiphy, dev, params);
+ trace_rdev_return_int(&rdev->wiphy, ret);
+ return ret;
+}
+
#endif /* __CFG80211_RDEV_OPS */
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 09af6eb..f0ebdcd 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -1841,6 +1841,39 @@ TRACE_EVENT(rdev_crit_proto_stop,
WIPHY_PR_ARG, WDEV_PR_ARG)
);
+TRACE_EVENT(rdev_channel_switch,
+ TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+ struct cfg80211_csa_settings *params),
+ TP_ARGS(wiphy, netdev, params),
+ TP_STRUCT__entry(
+ WIPHY_ENTRY
+ NETDEV_ENTRY
+ CHAN_DEF_ENTRY
+ __field(u16, counter_offset_beacon)
+ __field(u16, counter_offset_presp)
+ __field(bool, radar_required)
+ __field(bool, block_tx)
+ __field(u8, count)
+ ),
+ TP_fast_assign(
+ WIPHY_ASSIGN;
+ NETDEV_ASSIGN;
+ CHAN_DEF_ASSIGN(¶ms->chandef);
+ __entry->counter_offset_beacon = params->counter_offset_beacon;
+ __entry->counter_offset_presp = params->counter_offset_presp;
+ __entry->radar_required = params->radar_required;
+ __entry->block_tx = params->block_tx;
+ __entry->count = params->count;
+ ),
+ TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " CHAN_DEF_PR_FMT
+ ", block_tx: %d, count: %u, radar_required: %d"
+ ", counter offsets (beacon/presp): %u/%u",
+ WIPHY_PR_ARG, NETDEV_PR_ARG, CHAN_DEF_PR_ARG,
+ __entry->block_tx, __entry->count, __entry->radar_required,
+ __entry->counter_offset_beacon,
+ __entry->counter_offset_presp)
+);
+
/*************************************************************
* cfg80211 exported functions traces *
*************************************************************/
--
1.7.10.4
--
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