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mac80211: process the CSA frame for mesh accordingly

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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@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Chun-Yeow Yeoh 2013-10-14 19:08:27 -07:00 committed by Johannes Berg
parent c0f17eb9b2
commit 8f2535b92d
6 changed files with 134 additions and 3 deletions
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20
include/linux/ieee80211.h
View file

@ -696,6 +696,18 @@ struct ieee80211_sec_chan_offs_ie {
u8 sec_chan_offs;
} __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
*/
@ -750,6 +762,14 @@ enum mesh_config_capab_flags {
IEEE80211_MESHCONF_CAPAB_POWER_SAVE_LEVEL = 0x40,
};
/**
* 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
*

11
net/mac80211/Kconfig
View file

@ -259,6 +259,17 @@ 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

10
net/mac80211/debug.h
View file

@ -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__)

4
net/mac80211/ieee80211_i.h
View file

@ -603,6 +603,9 @@ 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
@ -1252,6 +1255,7 @@ 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;

83
net/mac80211/mesh.c
View file

@ -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 -ENOMEM;
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 forwarding 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();

9
net/mac80211/util.c
View file

@ -740,6 +740,7 @@ 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
@ -905,6 +906,14 @@ 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)) {