Process the CSA frame according to the procedures define in IEEE Std
802.11-2012 section 10.9.8.4.3 as follow:
* The mesh channel switch parameters element (MCSP) must be availabe.
* If the MCSP's TTL is 1, drop the frame but still process the CSA.
* If the MCSP's precedence value is less than or equal to the current
precedence value, drop the frame and do not process the CSA.
* The CSA frame is forwarded after TTL is decremented by 1 and the
initiator field is set to 0. Transmit restrict field and others
are maintained as is.
* No beacon or probe response frame are handled here.
Also, introduce the debug message used for mesh CSA purpose.
Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@xxxxxxxxxxx>
---
include/linux/ieee80211.h | 20 +++++++++++
net/mac80211/Kconfig | 11 ++++++
net/mac80211/debug.h | 10 ++++++
net/mac80211/ieee80211_i.h | 4 +++
net/mac80211/mesh.c | 83 ++++++++++++++++++++++++++++++++++++++++++--
net/mac80211/util.c | 9 +++++
6 files changed, 134 insertions(+), 3 deletions(-)
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 23a8877..f117427 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -696,6 +696,18 @@ struct ieee80211_sec_chan_offs_ie {
} __packed;
/**
+ * struct ieee80211_mesh_chansw_params_ie - mesh channel switch parameters IE
+ *
+ * This structure represents the "Mesh Channel Switch Paramters element"
+ */
+struct ieee80211_mesh_chansw_params_ie {
+ u8 mesh_ttl;
+ u8 mesh_flags;
+ __le16 mesh_reason;
+ __le16 mesh_pre_value;
+} __packed;
+
+/**
* struct ieee80211_wide_bw_chansw_ie - wide bandwidth channel switch IE
*/
struct ieee80211_wide_bw_chansw_ie {
@@ -750,6 +762,14 @@ enum mesh_config_capab_flags {
};
/**
+ * mesh channel switch parameters element's flag indicator
+ *
+ */
+#define WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT BIT(0)
+#define WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR BIT(1)
+#define WLAN_EID_CHAN_SWITCH_PARAM_REASON BIT(2)
+
+/**
* struct ieee80211_rann_ie
*
* This structure refers to "Root Announcement information element"
diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig
index 62535fe..bf1871e 100644
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -258,6 +258,17 @@ config MAC80211_MESH_SYNC_DEBUG
Do not select this option.
+config MAC80211_MESH_CSA_DEBUG
+ bool "Verbose mesh channel switch debugging"
+ depends on MAC80211_DEBUG_MENU
+ depends on MAC80211_MESH
+ ---help---
+ Selecting this option causes mac80211 to print out very verbose mesh
+ channel switch debugging messages (when mac80211 is taking part in a
+ mesh network).
+
+ Do not select this option.
+
config MAC80211_MESH_PS_DEBUG
bool "Verbose mesh powersave debugging"
depends on MAC80211_DEBUG_MENU
diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
index 4ccc5ed..493d680 100644
--- a/net/mac80211/debug.h
+++ b/net/mac80211/debug.h
@@ -44,6 +44,12 @@
#define MAC80211_MESH_SYNC_DEBUG 0
#endif
+#ifdef CONFIG_MAC80211_MESH_CSA_DEBUG
+#define MAC80211_MESH_CSA_DEBUG 1
+#else
+#define MAC80211_MESH_CSA_DEBUG 0
+#endif
+
#ifdef CONFIG_MAC80211_MESH_PS_DEBUG
#define MAC80211_MESH_PS_DEBUG 1
#else
@@ -157,6 +163,10 @@ do { \
_sdata_dbg(MAC80211_MESH_SYNC_DEBUG, \
sdata, fmt, ##__VA_ARGS__)
+#define mcsa_dbg(sdata, fmt, ...) \
+ _sdata_dbg(MAC80211_MESH_CSA_DEBUG, \
+ sdata, fmt, ##__VA_ARGS__)
+
#define mps_dbg(sdata, fmt, ...) \
_sdata_dbg(MAC80211_MESH_PS_DEBUG, \
sdata, fmt, ##__VA_ARGS__)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 3a87c89..7f13b65 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -598,6 +598,9 @@ struct ieee80211_if_mesh {
int ps_peers_light_sleep;
int ps_peers_deep_sleep;
struct ps_data ps;
+ /* Channel Switching Support */
+ bool chsw_init;
+ u16 pre_value;
};
#ifdef CONFIG_MAC80211_MESH
@@ -1239,6 +1242,7 @@ struct ieee802_11_elems {
const struct ieee80211_timeout_interval_ie *timeout_int;
const u8 *opmode_notif;
const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
+ const struct ieee80211_mesh_chansw_params_ie *mesh_chansw_params_ie;
/* length of them, respectively */
u8 ssid_len;
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 707ac61..308ef98 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -920,6 +920,82 @@ static void ieee80211_mesh_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
stype, mgmt, &elems, rx_status);
}
+static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_mgmt *mgmt, size_t len)
+{
+ struct ieee80211_mgmt *mgmt_fwd;
+ struct sk_buff *skb;
+ struct ieee80211_local *local = sdata->local;
+ u8 *pos = mgmt->u.action.u.chan_switch.variable;
+ size_t offset_ttl;
+
+ skb = dev_alloc_skb(local->tx_headroom + len);
+ if (!skb)
+ return -1;
+ skb_reserve(skb, local->tx_headroom);
+ mgmt_fwd = (struct ieee80211_mgmt *) skb_put(skb, len);
+
+ /* offset_ttl is based on whether the secondary channel
+ * offset is available or not. Substract 1 from the mesh TTL
+ * and disable the initiator flag before forwarding.
+ */
+ offset_ttl = (len < 42) ? 7 : 10;
+ *(pos + offset_ttl) -= 1;
+ *(pos + offset_ttl + 1) &= ~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
+
+ memcpy(mgmt_fwd, mgmt, len);
+ eth_broadcast_addr(mgmt_fwd->da);
+ memcpy(mgmt_fwd->sa, sdata->vif.addr, ETH_ALEN);
+ memcpy(mgmt_fwd->bssid, sdata->vif.addr, ETH_ALEN);
+
+ ieee80211_tx_skb(sdata, skb);
+ return 0;
+}
+
+static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_mgmt *mgmt, size_t len)
+{
+ struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+ struct ieee802_11_elems elems;
+ u16 pre_value;
+ bool block_tx, fwd_csa = true;
+ size_t baselen;
+ u8 *pos, ttl;
+
+ if (mgmt->u.action.u.measurement.action_code !=
+ WLAN_ACTION_SPCT_CHL_SWITCH)
+ return;
+
+ pos = mgmt->u.action.u.chan_switch.variable;
+ baselen = offsetof(struct ieee80211_mgmt,
+ u.action.u.chan_switch.variable);
+ ieee802_11_parse_elems(pos, len - baselen, false, &elems);
+
+ ttl = elems.mesh_chansw_params_ie->mesh_ttl;
+ if (!--ttl)
+ fwd_csa = false;
+
+ pre_value = le16_to_cpu(elems.mesh_chansw_params_ie->mesh_pre_value);
+ if (ifmsh->pre_value >= pre_value)
+ return;
+
+ ifmsh->pre_value = pre_value;
+
+ /* forward or re-broadcast the CSA frame */
+ if (fwd_csa) {
+ if (mesh_fwd_csa_frame(sdata, mgmt, len) < 0)
+ mcsa_dbg(sdata, "Failed to forward the CSA frame");
+ }
+
+ /* block the Tx only after fowarding the CSA frame if required */
+ block_tx = !!(elems.mesh_chansw_params_ie->mesh_flags
+ & WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT);
+ if (block_tx)
+ ieee80211_stop_queues_by_reason(&sdata->local->hw,
+ IEEE80211_MAX_QUEUE_MAP,
+ IEEE80211_QUEUE_STOP_REASON_CSA);
+}
+
static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
size_t len,
@@ -939,6 +1015,9 @@ static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
if (mesh_action_is_path_sel(mgmt))
mesh_rx_path_sel_frame(sdata, mgmt, len);
break;
+ case WLAN_CATEGORY_SPECTRUM_MGMT:
+ mesh_rx_csa_frame(sdata, mgmt, len);
+ break;
}
}
@@ -1056,13 +1135,11 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
(unsigned long) sdata);
ifmsh->accepting_plinks = true;
- ifmsh->preq_id = 0;
- ifmsh->sn = 0;
- ifmsh->num_gates = 0;
atomic_set(&ifmsh->mpaths, 0);
mesh_rmc_init(sdata);
ifmsh->last_preq = jiffies;
ifmsh->next_perr = jiffies;
+ ifmsh->chsw_init = false;
/* Allocate all mesh structures when creating the first mesh interface. */
if (!mesh_allocated)
ieee80211s_init();
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 3c8283b..133667c 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -743,6 +743,7 @@ u32 ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
case WLAN_EID_TIMEOUT_INTERVAL:
case WLAN_EID_SECONDARY_CHANNEL_OFFSET:
case WLAN_EID_WIDE_BW_CHANNEL_SWITCH:
+ case WLAN_EID_CHAN_SWITCH_PARAM:
/*
* not listing WLAN_EID_CHANNEL_SWITCH_WRAPPER -- it seems possible
* that if the content gets bigger it might be needed more than once
@@ -908,6 +909,14 @@ u32 ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
}
elems->sec_chan_offs = (void *)pos;
break;
+ case WLAN_EID_CHAN_SWITCH_PARAM:
+ if (elen !=
+ sizeof(*elems->mesh_chansw_params_ie)) {
+ elem_parse_failed = true;
+ break;
+ }
+ elems->mesh_chansw_params_ie = (void *)pos;
+ break;
case WLAN_EID_WIDE_BW_CHANNEL_SWITCH:
if (!action ||
elen != sizeof(*elems->wide_bw_chansw_ie)) {
--
1.7.9.5
--
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