From 8f2535b92d685c68db4bc699dd78462a646f6ef9 Mon Sep 17 00:00:00 2001 From: Chun-Yeow Yeoh Date: Mon, 14 Oct 2013 19:08:27 -0700 Subject: mac80211: process the CSA frame for mesh accordingly 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 Signed-off-by: Johannes Berg --- net/mac80211/mesh.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 80 insertions(+), 3 deletions(-) (limited to 'net/mac80211/mesh.c') diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index 707ac61d63e5..0a3ccaa275f9 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 -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(); -- cgit v1.2.3