*
*****************************************************************************/
+#include <linux/etherdevice.h>
#include "mvm.h"
#include "time-event.h"
+#define TU_TO_US(x) (x * 1024)
+#define TU_TO_MS(x) (TU_TO_US(x) / 1000)
+
void iwl_mvm_teardown_tdls_peers(struct iwl_mvm *mvm)
{
struct ieee80211_sta *sta;
return count;
}
+static void iwl_mvm_tdls_config(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
+{
+ struct iwl_rx_packet *pkt;
+ struct iwl_tdls_config_res *resp;
+ struct iwl_tdls_config_cmd tdls_cfg_cmd = {};
+ struct iwl_host_cmd cmd = {
+ .id = TDLS_CONFIG_CMD,
+ .flags = CMD_WANT_SKB,
+ .data = { &tdls_cfg_cmd, },
+ .len = { sizeof(struct iwl_tdls_config_cmd), },
+ };
+ struct ieee80211_sta *sta;
+ int ret, i, cnt;
+ struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+
+ lockdep_assert_held(&mvm->mutex);
+
+ tdls_cfg_cmd.id_and_color =
+ cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));
+ tdls_cfg_cmd.tx_to_ap_tid = IWL_MVM_TDLS_FW_TID;
+ tdls_cfg_cmd.tx_to_ap_ssn = cpu_to_le16(0); /* not used for now */
+
+ /* for now the Tx cmd is empty and unused */
+
+ /* populate TDLS peer data */
+ cnt = 0;
+ for (i = 0; i < IWL_MVM_STATION_COUNT; i++) {
+ sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i],
+ lockdep_is_held(&mvm->mutex));
+ if (IS_ERR_OR_NULL(sta) || !sta->tdls)
+ continue;
+
+ tdls_cfg_cmd.sta_info[cnt].sta_id = i;
+ tdls_cfg_cmd.sta_info[cnt].tx_to_peer_tid =
+ IWL_MVM_TDLS_FW_TID;
+ tdls_cfg_cmd.sta_info[cnt].tx_to_peer_ssn = cpu_to_le16(0);
+ tdls_cfg_cmd.sta_info[cnt].is_initiator =
+ cpu_to_le32(sta->tdls_initiator ? 1 : 0);
+
+ cnt++;
+ }
+
+ tdls_cfg_cmd.tdls_peer_count = cnt;
+ IWL_DEBUG_TDLS(mvm, "send TDLS config to FW for %d peers\n", cnt);
+
+ ret = iwl_mvm_send_cmd(mvm, &cmd);
+ if (WARN_ON_ONCE(ret))
+ return;
+
+ pkt = cmd.resp_pkt;
+ if (pkt->hdr.flags & IWL_CMD_FAILED_MSK) {
+ IWL_ERR(mvm, "Bad return from TDLS_CONFIG_COMMAND (0x%08X)\n",
+ pkt->hdr.flags);
+ goto exit;
+ }
+
+ if (WARN_ON_ONCE(iwl_rx_packet_payload_len(pkt) != sizeof(*resp)))
+ goto exit;
+
+ /* we don't really care about the response at this point */
+
+exit:
+ iwl_free_resp(&cmd);
+}
+
void iwl_mvm_recalc_tdls_state(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
bool sta_added)
{
int tdls_sta_cnt = iwl_mvm_tdls_sta_count(mvm, vif);
- /*
- * Disable ps when the first TDLS sta is added and re-enable it
- * when the last TDLS sta is removed
- */
- if ((tdls_sta_cnt == 1 && sta_added) ||
- (tdls_sta_cnt == 0 && !sta_added))
+ /* when the first peer joins, send a power update first */
+ if (tdls_sta_cnt == 1 && sta_added)
+ iwl_mvm_power_update_mac(mvm);
+
+ /* configure the FW with TDLS peer info */
+ iwl_mvm_tdls_config(mvm, vif);
+
+ /* when the last peer leaves, send a power update last */
+ if (tdls_sta_cnt == 0 && !sta_added)
iwl_mvm_power_update_mac(mvm);
}
iwl_mvm_unref(mvm, IWL_MVM_REF_PROTECT_TDLS);
}
+
+static const char *
+iwl_mvm_tdls_cs_state_str(enum iwl_mvm_tdls_cs_state state)
+{
+ switch (state) {
+ case IWL_MVM_TDLS_SW_IDLE:
+ return "IDLE";
+ case IWL_MVM_TDLS_SW_REQ_SENT:
+ return "REQ SENT";
+ case IWL_MVM_TDLS_SW_REQ_RCVD:
+ return "REQ RECEIVED";
+ case IWL_MVM_TDLS_SW_ACTIVE:
+ return "ACTIVE";
+ }
+
+ return NULL;
+}
+
+static void iwl_mvm_tdls_update_cs_state(struct iwl_mvm *mvm,
+ enum iwl_mvm_tdls_cs_state state)
+{
+ if (mvm->tdls_cs.state == state)
+ return;
+
+ IWL_DEBUG_TDLS(mvm, "TDLS channel switch state: %s -> %s\n",
+ iwl_mvm_tdls_cs_state_str(mvm->tdls_cs.state),
+ iwl_mvm_tdls_cs_state_str(state));
+ mvm->tdls_cs.state = state;
+
+ if (state == IWL_MVM_TDLS_SW_IDLE)
+ mvm->tdls_cs.cur_sta_id = IWL_MVM_STATION_COUNT;
+}
+
+int iwl_mvm_rx_tdls_notif(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
+ struct iwl_device_cmd *cmd)
+{
+ struct iwl_rx_packet *pkt = rxb_addr(rxb);
+ struct iwl_tdls_channel_switch_notif *notif = (void *)pkt->data;
+ struct ieee80211_sta *sta;
+ unsigned int delay;
+ struct iwl_mvm_sta *mvmsta;
+ struct ieee80211_vif *vif;
+ u32 sta_id = le32_to_cpu(notif->sta_id);
+
+ lockdep_assert_held(&mvm->mutex);
+
+ /* can fail sometimes */
+ if (!le32_to_cpu(notif->status)) {
+ iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);
+ goto out;
+ }
+
+ if (WARN_ON(sta_id >= IWL_MVM_STATION_COUNT))
+ goto out;
+
+ sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[sta_id],
+ lockdep_is_held(&mvm->mutex));
+ /* the station may not be here, but if it is, it must be a TDLS peer */
+ if (IS_ERR_OR_NULL(sta) || WARN_ON(!sta->tdls))
+ goto out;
+
+ mvmsta = iwl_mvm_sta_from_mac80211(sta);
+ vif = mvmsta->vif;
+
+ /*
+ * Update state and possibly switch again after this is over (DTIM).
+ * Also convert TU to msec.
+ */
+ delay = TU_TO_MS(vif->bss_conf.dtim_period * vif->bss_conf.beacon_int);
+ mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
+ msecs_to_jiffies(delay));
+
+ iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_ACTIVE);
+
+out:
+ return 0;
+}
+
+static int
+iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
+ enum iwl_tdls_channel_switch_type type,
+ const u8 *peer, bool peer_initiator)
+{
+ bool same_peer = false;
+ int ret = 0;
+
+ /* get the existing peer if it's there */
+ if (mvm->tdls_cs.state != IWL_MVM_TDLS_SW_IDLE &&
+ mvm->tdls_cs.cur_sta_id != IWL_MVM_STATION_COUNT) {
+ struct ieee80211_sta *sta = rcu_dereference_protected(
+ mvm->fw_id_to_mac_id[mvm->tdls_cs.cur_sta_id],
+ lockdep_is_held(&mvm->mutex));
+ if (!IS_ERR_OR_NULL(sta))
+ same_peer = ether_addr_equal(peer, sta->addr);
+ }
+
+ switch (mvm->tdls_cs.state) {
+ case IWL_MVM_TDLS_SW_IDLE:
+ /*
+ * might be spurious packet from the peer after the switch is
+ * already done
+ */
+ if (type == TDLS_MOVE_CH)
+ ret = -EINVAL;
+ break;
+ case IWL_MVM_TDLS_SW_REQ_SENT:
+ /*
+ * We received a ch-switch request while an outgoing one is
+ * pending. Allow it to proceed if the other peer is the same
+ * one we sent to, and we are not the link initiator.
+ */
+ if (type == TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH) {
+ if (!same_peer)
+ ret = -EBUSY;
+ else if (!peer_initiator) /* we are the initiator */
+ ret = -EBUSY;
+ }
+ break;
+ case IWL_MVM_TDLS_SW_REQ_RCVD:
+ /* as above, allow the link initiator to proceed */
+ if (type == TDLS_SEND_CHAN_SW_REQ) {
+ if (!same_peer)
+ ret = -EBUSY;
+ else if (peer_initiator) /* they are the initiator */
+ ret = -EBUSY;
+ } else if (type == TDLS_MOVE_CH) {
+ ret = -EINVAL;
+ }
+ break;
+ case IWL_MVM_TDLS_SW_ACTIVE:
+ /* we don't allow initiations during active channel switch */
+ if (type == TDLS_SEND_CHAN_SW_REQ)
+ ret = -EINVAL;
+ break;
+ }
+
+ if (ret)
+ IWL_DEBUG_TDLS(mvm,
+ "Invalid TDLS action %d state %d peer %pM same_peer %d initiator %d\n",
+ type, mvm->tdls_cs.state, peer, same_peer,
+ peer_initiator);
+
+ return ret;
+}
+
+static int
+iwl_mvm_tdls_config_channel_switch(struct iwl_mvm *mvm,
+ struct ieee80211_vif *vif,
+ enum iwl_tdls_channel_switch_type type,
+ const u8 *peer, bool peer_initiator,
+ u8 oper_class,
+ struct cfg80211_chan_def *chandef,
+ u32 timestamp, u16 switch_time,
+ u16 switch_timeout, struct sk_buff *skb,
+ u32 ch_sw_tm_ie)
+{
+ struct ieee80211_sta *sta;
+ struct iwl_mvm_sta *mvmsta;
+ struct ieee80211_tx_info *info;
+ struct ieee80211_hdr *hdr;
+ struct iwl_tdls_channel_switch_cmd cmd = {0};
+ int ret;
+
+ lockdep_assert_held(&mvm->mutex);
+
+ ret = iwl_mvm_tdls_check_action(mvm, type, peer, peer_initiator);
+ if (ret)
+ return ret;
+
+ if (!skb || WARN_ON(skb->len > IWL_TDLS_CH_SW_FRAME_MAX_SIZE)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ cmd.switch_type = type;
+ cmd.timing.frame_timestamp = cpu_to_le32(timestamp);
+ cmd.timing.switch_time = cpu_to_le32(switch_time);
+ cmd.timing.switch_timeout = cpu_to_le32(switch_timeout);
+
+ rcu_read_lock();
+ sta = ieee80211_find_sta(vif, peer);
+ if (!sta) {
+ rcu_read_unlock();
+ ret = -ENOENT;
+ goto out;
+ }
+ mvmsta = iwl_mvm_sta_from_mac80211(sta);
+ cmd.peer_sta_id = cpu_to_le32(mvmsta->sta_id);
+
+ if (!chandef) {
+ if (mvm->tdls_cs.state == IWL_MVM_TDLS_SW_REQ_SENT &&
+ mvm->tdls_cs.peer.chandef.chan) {
+ /* actually moving to the channel */
+ chandef = &mvm->tdls_cs.peer.chandef;
+ } else if (mvm->tdls_cs.state == IWL_MVM_TDLS_SW_ACTIVE &&
+ type == TDLS_MOVE_CH) {
+ /* we need to return to base channel */
+ struct ieee80211_chanctx_conf *chanctx =
+ rcu_dereference(vif->chanctx_conf);
+
+ if (WARN_ON_ONCE(!chanctx)) {
+ rcu_read_unlock();
+ goto out;
+ }
+
+ chandef = &chanctx->def;
+ }
+ }
+
+ if (chandef) {
+ cmd.ci.band = (chandef->chan->band == IEEE80211_BAND_2GHZ ?
+ PHY_BAND_24 : PHY_BAND_5);
+ cmd.ci.channel = chandef->chan->hw_value;
+ cmd.ci.width = iwl_mvm_get_channel_width(chandef);
+ cmd.ci.ctrl_pos = iwl_mvm_get_ctrl_pos(chandef);
+ }
+
+ /* keep quota calculation simple for now - 50% of DTIM for TDLS */
+ cmd.timing.max_offchan_duration =
+ cpu_to_le32(TU_TO_US(vif->bss_conf.dtim_period *
+ vif->bss_conf.beacon_int) / 2);
+
+ /* Switch time is the first element in the switch-timing IE. */
+ cmd.frame.switch_time_offset = cpu_to_le32(ch_sw_tm_ie + 2);
+
+ info = IEEE80211_SKB_CB(skb);
+ if (info->control.hw_key)
+ iwl_mvm_set_tx_cmd_crypto(mvm, info, &cmd.frame.tx_cmd, skb);
+
+ iwl_mvm_set_tx_cmd(mvm, skb, &cmd.frame.tx_cmd, info,
+ mvmsta->sta_id);
+
+ hdr = (void *)skb->data;
+ iwl_mvm_set_tx_cmd_rate(mvm, &cmd.frame.tx_cmd, info, sta,
+ hdr->frame_control);
+ rcu_read_unlock();
+
+ memcpy(cmd.frame.data, skb->data, skb->len);
+
+ ret = iwl_mvm_send_cmd_pdu(mvm, TDLS_CHANNEL_SWITCH_CMD, 0,
+ sizeof(cmd), &cmd);
+ if (ret) {
+ IWL_ERR(mvm, "Failed to send TDLS_CHANNEL_SWITCH cmd: %d\n",
+ ret);
+ goto out;
+ }
+
+ /* channel switch has started, update state */
+ if (type != TDLS_MOVE_CH) {
+ mvm->tdls_cs.cur_sta_id = mvmsta->sta_id;
+ iwl_mvm_tdls_update_cs_state(mvm,
+ type == TDLS_SEND_CHAN_SW_REQ ?
+ IWL_MVM_TDLS_SW_REQ_SENT :
+ IWL_MVM_TDLS_SW_REQ_RCVD);
+ }
+
+out:
+
+ /* channel switch failed - we are idle */
+ if (ret)
+ iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);
+
+ return ret;
+}
+
+void iwl_mvm_tdls_ch_switch_work(struct work_struct *work)
+{
+ struct iwl_mvm *mvm;
+ struct ieee80211_sta *sta;
+ struct iwl_mvm_sta *mvmsta;
+ struct ieee80211_vif *vif;
+ unsigned int delay;
+ int ret;
+
+ mvm = container_of(work, struct iwl_mvm, tdls_cs.dwork.work);
+ mutex_lock(&mvm->mutex);
+
+ /* called after an active channel switch has finished or timed-out */
+ iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);
+
+ /* station might be gone, in that case do nothing */
+ if (mvm->tdls_cs.peer.sta_id == IWL_MVM_STATION_COUNT)
+ goto out;
+
+ sta = rcu_dereference_protected(
+ mvm->fw_id_to_mac_id[mvm->tdls_cs.peer.sta_id],
+ lockdep_is_held(&mvm->mutex));
+ /* the station may not be here, but if it is, it must be a TDLS peer */
+ if (!sta || IS_ERR(sta) || WARN_ON(!sta->tdls))
+ goto out;
+
+ mvmsta = iwl_mvm_sta_from_mac80211(sta);
+ vif = mvmsta->vif;
+ ret = iwl_mvm_tdls_config_channel_switch(mvm, vif,
+ TDLS_SEND_CHAN_SW_REQ,
+ sta->addr,
+ mvm->tdls_cs.peer.initiator,
+ mvm->tdls_cs.peer.op_class,
+ &mvm->tdls_cs.peer.chandef,
+ 0, 0, 0,
+ mvm->tdls_cs.peer.skb,
+ mvm->tdls_cs.peer.ch_sw_tm_ie);
+ if (ret)
+ IWL_ERR(mvm, "Not sending TDLS channel switch: %d\n", ret);
+
+ /* retry after a DTIM if we failed sending now */
+ delay = TU_TO_MS(vif->bss_conf.dtim_period * vif->bss_conf.beacon_int);
+ queue_delayed_work(system_wq, &mvm->tdls_cs.dwork,
+ msecs_to_jiffies(delay));
+out:
+ mutex_unlock(&mvm->mutex);
+}
+
+int
+iwl_mvm_tdls_channel_switch(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct ieee80211_sta *sta, u8 oper_class,
+ struct cfg80211_chan_def *chandef,
+ struct sk_buff *tmpl_skb, u32 ch_sw_tm_ie)
+{
+ struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+ struct iwl_mvm_sta *mvmsta;
+ unsigned int delay;
+ int ret;
+
+ mutex_lock(&mvm->mutex);
+
+ IWL_DEBUG_TDLS(mvm, "TDLS channel switch with %pM ch %d width %d\n",
+ sta->addr, chandef->chan->center_freq, chandef->width);
+
+ /* we only support a single peer for channel switching */
+ if (mvm->tdls_cs.peer.sta_id != IWL_MVM_STATION_COUNT) {
+ IWL_DEBUG_TDLS(mvm,
+ "Existing peer. Can't start switch with %pM\n",
+ sta->addr);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ ret = iwl_mvm_tdls_config_channel_switch(mvm, vif,
+ TDLS_SEND_CHAN_SW_REQ,
+ sta->addr, sta->tdls_initiator,
+ oper_class, chandef, 0, 0, 0,
+ tmpl_skb, ch_sw_tm_ie);
+ if (ret)
+ goto out;
+
+ /*
+ * Mark the peer as "in tdls switch" for this vif. We only allow a
+ * single such peer per vif.
+ */
+ mvm->tdls_cs.peer.skb = skb_copy(tmpl_skb, GFP_KERNEL);
+ if (!mvm->tdls_cs.peer.skb) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mvmsta = iwl_mvm_sta_from_mac80211(sta);
+ mvm->tdls_cs.peer.sta_id = mvmsta->sta_id;
+ mvm->tdls_cs.peer.chandef = *chandef;
+ mvm->tdls_cs.peer.initiator = sta->tdls_initiator;
+ mvm->tdls_cs.peer.op_class = oper_class;
+ mvm->tdls_cs.peer.ch_sw_tm_ie = ch_sw_tm_ie;
+
+ /*
+ * Wait for 2 DTIM periods before attempting the next switch. The next
+ * switch will be made sooner if the current one completes before that.
+ */
+ delay = 2 * TU_TO_MS(vif->bss_conf.dtim_period *
+ vif->bss_conf.beacon_int);
+ mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
+ msecs_to_jiffies(delay));
+
+out:
+ mutex_unlock(&mvm->mutex);
+ return ret;
+}
+
+void iwl_mvm_tdls_cancel_channel_switch(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct ieee80211_sta *sta)
+{
+ struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+ struct ieee80211_sta *cur_sta;
+ bool wait_for_phy = false;
+
+ mutex_lock(&mvm->mutex);
+
+ IWL_DEBUG_TDLS(mvm, "TDLS cancel channel switch with %pM\n", sta->addr);
+
+ /* we only support a single peer for channel switching */
+ if (mvm->tdls_cs.peer.sta_id == IWL_MVM_STATION_COUNT) {
+ IWL_DEBUG_TDLS(mvm, "No ch switch peer - %pM\n", sta->addr);
+ goto out;
+ }
+
+ cur_sta = rcu_dereference_protected(
+ mvm->fw_id_to_mac_id[mvm->tdls_cs.peer.sta_id],
+ lockdep_is_held(&mvm->mutex));
+ /* make sure it's the same peer */
+ if (cur_sta != sta)
+ goto out;
+
+ /*
+ * If we're currently in a switch because of the now canceled peer,
+ * wait a DTIM here to make sure the phy is back on the base channel.
+ * We can't otherwise force it.
+ */
+ if (mvm->tdls_cs.cur_sta_id == mvm->tdls_cs.peer.sta_id &&
+ mvm->tdls_cs.state != IWL_MVM_TDLS_SW_IDLE)
+ wait_for_phy = true;
+
+ mvm->tdls_cs.peer.sta_id = IWL_MVM_STATION_COUNT;
+ dev_kfree_skb(mvm->tdls_cs.peer.skb);
+ mvm->tdls_cs.peer.skb = NULL;
+
+out:
+ mutex_unlock(&mvm->mutex);
+
+ /* make sure the phy is on the base channel */
+ if (wait_for_phy)
+ msleep(TU_TO_MS(vif->bss_conf.dtim_period *
+ vif->bss_conf.beacon_int));
+
+ /* flush the channel switch state */
+ flush_delayed_work(&mvm->tdls_cs.dwork);
+
+ IWL_DEBUG_TDLS(mvm, "TDLS ending channel switch with %pM\n", sta->addr);
+}
+
+void
+iwl_mvm_tdls_recv_channel_switch(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct ieee80211_tdls_ch_sw_params *params)
+{
+ struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+ enum iwl_tdls_channel_switch_type type;
+ unsigned int delay;
+
+ mutex_lock(&mvm->mutex);
+
+ IWL_DEBUG_TDLS(mvm,
+ "Received TDLS ch switch action %d from %pM status %d\n",
+ params->action_code, params->sta->addr, params->status);
+
+ /*
+ * we got a non-zero status from a peer we were switching to - move to
+ * the idle state and retry again later
+ */
+ if (params->action_code == WLAN_TDLS_CHANNEL_SWITCH_RESPONSE &&
+ params->status != 0 &&
+ mvm->tdls_cs.state == IWL_MVM_TDLS_SW_REQ_SENT &&
+ mvm->tdls_cs.cur_sta_id != IWL_MVM_STATION_COUNT) {
+ struct ieee80211_sta *cur_sta;
+
+ /* make sure it's the same peer */
+ cur_sta = rcu_dereference_protected(
+ mvm->fw_id_to_mac_id[mvm->tdls_cs.cur_sta_id],
+ lockdep_is_held(&mvm->mutex));
+ if (cur_sta == params->sta) {
+ iwl_mvm_tdls_update_cs_state(mvm,
+ IWL_MVM_TDLS_SW_IDLE);
+ goto retry;
+ }
+ }
+
+ type = (params->action_code == WLAN_TDLS_CHANNEL_SWITCH_REQUEST) ?
+ TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH : TDLS_MOVE_CH;
+
+ iwl_mvm_tdls_config_channel_switch(mvm, vif, type, params->sta->addr,
+ params->sta->tdls_initiator, 0,
+ params->chandef, params->timestamp,
+ params->switch_time,
+ params->switch_timeout,
+ params->tmpl_skb,
+ params->ch_sw_tm_ie);
+
+retry:
+ /* register a timeout in case we don't succeed in switching */
+ delay = vif->bss_conf.dtim_period * vif->bss_conf.beacon_int *
+ 1024 / 1000;
+ mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
+ msecs_to_jiffies(delay));
+ mutex_unlock(&mvm->mutex);
+}
projects / cascardo / linux.git / blobdiff