ble_mesh: fix adhering to the configured Friend Queue size

components/bt/esp_ble_mesh/mesh_core/friend.c

@@ -70,48 +70,6 @@ static struct bt_mesh_adv *adv_alloc(int id)
     return &adv_pool[id].adv;
 }
 
-static void discard_buffer(void)
-{
-    struct bt_mesh_friend *frnd = &bt_mesh.frnd[0];
-    struct net_buf *buf;
-    int i;
-
-    /* Find the Friend context with the most queued buffers */
-    for (i = 1; i < ARRAY_SIZE(bt_mesh.frnd); i++) {
-        if (bt_mesh.frnd[i].queue_size > frnd->queue_size) {
-            frnd = &bt_mesh.frnd[i];
-        }
-    }
-
-    buf = net_buf_slist_get(&frnd->queue);
-    __ASSERT_NO_MSG(buf != NULL);
-    BT_WARN("Discarding buffer %p for LPN 0x%04x", buf, frnd->lpn);
-    net_buf_unref(buf);
-}
-
-static struct net_buf *friend_buf_alloc(u16_t src)
-{
-    struct net_buf *buf;
-
-    BT_DBG("src 0x%04x", src);
-
-    do {
-        buf = bt_mesh_adv_create_from_pool(&friend_buf_pool, adv_alloc,
-                                           BLE_MESH_ADV_DATA,
-                                           FRIEND_XMIT, K_NO_WAIT);
-        if (!buf) {
-            discard_buffer();
-        }
-    } while (!buf);
-
-    BLE_MESH_ADV(buf)->addr = src;
-    FRIEND_ADV(buf)->seq_auth = TRANS_SEQ_AUTH_NVAL;
-
-    BT_DBG("allocated buf %p", buf);
-
-    return buf;
-}
-
 static bool is_lpn_unicast(struct bt_mesh_friend *frnd, u16_t addr)
 {
     if (frnd->lpn == BLE_MESH_ADDR_UNASSIGNED) {
@@ -151,6 +109,20 @@ struct bt_mesh_friend *bt_mesh_friend_find(u16_t net_idx, u16_t lpn_addr,
     return NULL;
 }
 
+static void purge_buffers(sys_slist_t *list)
+{
+    while (!sys_slist_is_empty(list)) {
+        struct net_buf *buf;
+
+        buf = (void *)sys_slist_get_not_empty(list);
+
+        buf->frags = NULL;
+        buf->flags &= ~NET_BUF_FRAGS;
+
+        net_buf_unref(buf);
+    }
+}
+
 /* Intentionally start a little bit late into the ReceiveWindow when
  * it's large enough. This may improve reliability with some platforms,
  * like the PTS, where the receiver might not have sufficiently compensated
@@ -185,16 +157,13 @@ static void friend_clear(struct bt_mesh_friend *frnd)
         frnd->last = NULL;
     }
 
-    while (!sys_slist_is_empty(&frnd->queue)) {
+    purge_buffers(&frnd->queue);
-        net_buf_unref(net_buf_slist_get(&frnd->queue));
-    }
 
     for (i = 0; i < ARRAY_SIZE(frnd->seg); i++) {
         struct bt_mesh_friend_seg *seg = &frnd->seg[i];
 
-        while (!sys_slist_is_empty(&seg->queue)) {
+        purge_buffers(&seg->queue);
-            net_buf_unref(net_buf_slist_get(&seg->queue));
+        seg->seg_count = 0U;
-        }
     }
 
     frnd->valid = 0U;
@@ -336,7 +305,15 @@ static struct net_buf *create_friend_pdu(struct bt_mesh_friend *frnd,
     sub = bt_mesh_subnet_get(frnd->net_idx);
     __ASSERT_NO_MSG(sub != NULL);
 
-    buf = friend_buf_alloc(info->src);
+    buf = bt_mesh_adv_create_from_pool(&friend_buf_pool, adv_alloc,
+                                       BLE_MESH_ADV_DATA,
+                                       FRIEND_XMIT, K_NO_WAIT);
+    if (!buf) {
+        return NULL;
+    }
+
+    BLE_MESH_ADV(buf)->addr = info->src;
+    FRIEND_ADV(buf)->seq_auth = TRANS_SEQ_AUTH_NVAL;
 
     /* Friend Offer needs master security credentials */
     if (info->ctl && TRANS_CTL_OP(sdu->data) == TRANS_CTL_OP_FRIEND_OFFER) {
@@ -897,7 +874,8 @@ init_friend:
 }
 
 static struct bt_mesh_friend_seg *get_seg(struct bt_mesh_friend *frnd,
-        u16_t src, u64_t *seq_auth)
+                                          u16_t src, u64_t *seq_auth,
+                                          u8_t seg_count)
 {
     struct bt_mesh_friend_seg *unassigned = NULL;
     int i;
@@ -916,12 +894,16 @@ static struct bt_mesh_friend_seg *get_seg(struct bt_mesh_friend *frnd,
         }
     }
 
+    if (unassigned) {
+        unassigned->seg_count = seg_count;
+    }
+
     return unassigned;
 }
 
 static void enqueue_friend_pdu(struct bt_mesh_friend *frnd,
                                enum bt_mesh_friend_pdu_type type,
-                               struct net_buf *buf)
+                               u8_t seg_count, struct net_buf *buf)
 {
     struct bt_mesh_friend_seg *seg;
     struct friend_adv *adv;
@@ -938,7 +920,7 @@ static void enqueue_friend_pdu(struct bt_mesh_friend *frnd,
     }
 
     adv = FRIEND_ADV(buf);
-    seg = get_seg(frnd, BLE_MESH_ADV(buf)->addr, &adv->seq_auth);
+    seg = get_seg(frnd, BLE_MESH_ADV(buf)->addr, &adv->seq_auth, seg_count);
     if (!seg) {
         BT_ERR("%s, No free friend segment RX contexts for 0x%04x",
                 __func__, BLE_MESH_ADV(buf)->addr);
@@ -963,6 +945,10 @@ static void enqueue_friend_pdu(struct bt_mesh_friend *frnd,
         }
 
         sys_slist_merge_slist(&frnd->queue, &seg->queue);
+        seg->seg_count = 0U;
+    } else {
+        /* Mark the buffer as having more to come after it */
+        buf->flags |= NET_BUF_FRAGS;
     }
 }
 
@@ -1028,13 +1014,17 @@ static void friend_timeout(struct k_work *work)
         return;
     }
 
-    frnd->last = net_buf_slist_get(&frnd->queue);
+    frnd->last = (void *)sys_slist_get(&frnd->queue);
     if (!frnd->last) {
         BT_WARN("%s, Friendship not established with 0x%04x", __func__, frnd->lpn);
         friend_clear(frnd);
         return;
     }
 
+    /* Clear the flag we use for segment tracking */
+    frnd->last->flags &= ~NET_BUF_FRAGS;
+    frnd->last->frags = NULL;
+
     BT_DBG("Sending buf %p from Friend Queue of LPN 0x%04x",
            frnd->last, frnd->lpn);
     frnd->queue_size--;
@@ -1097,7 +1087,8 @@ static void friend_purge_old_ack(struct bt_mesh_friend *frnd, u64_t *seq_auth,
 static void friend_lpn_enqueue_rx(struct bt_mesh_friend *frnd,
                                   struct bt_mesh_net_rx *rx,
                                   enum bt_mesh_friend_pdu_type type,
-                                  u64_t *seq_auth, struct net_buf_simple *sbuf)
+                                  u64_t *seq_auth, u8_t seg_count,
+                                  struct net_buf_simple *sbuf)
 {
     struct friend_pdu_info info;
     struct net_buf *buf;
@@ -1135,7 +1126,7 @@ static void friend_lpn_enqueue_rx(struct bt_mesh_friend *frnd,
         FRIEND_ADV(buf)->seq_auth = *seq_auth;
     }
 
-    enqueue_friend_pdu(frnd, type, buf);
+    enqueue_friend_pdu(frnd, type, seg_count, buf);
 
     BT_DBG("Queued message for LPN 0x%04x, queue_size %u",
            frnd->lpn, frnd->queue_size);
@@ -1144,7 +1135,8 @@ static void friend_lpn_enqueue_rx(struct bt_mesh_friend *frnd,
 static void friend_lpn_enqueue_tx(struct bt_mesh_friend *frnd,
                                   struct bt_mesh_net_tx *tx,
                                   enum bt_mesh_friend_pdu_type type,
-                                  u64_t *seq_auth, struct net_buf_simple *sbuf)
+                                  u64_t *seq_auth, u8_t seg_count,
+                                  struct net_buf_simple *sbuf)
 {
     struct friend_pdu_info info;
     struct net_buf *buf;
@@ -1179,7 +1171,7 @@ static void friend_lpn_enqueue_tx(struct bt_mesh_friend *frnd,
         FRIEND_ADV(buf)->seq_auth = *seq_auth;
     }
 
-    enqueue_friend_pdu(frnd, type, buf);
+    enqueue_friend_pdu(frnd, type, seg_count, buf);
 
     BT_DBG("Queued message for LPN 0x%04x", frnd->lpn);
 }
@@ -1229,9 +1221,118 @@ bool bt_mesh_friend_match(u16_t net_idx, u16_t addr)
     return false;
 }
 
+static bool friend_queue_has_space(struct bt_mesh_friend *frnd, u16_t addr,
+                                   u64_t *seq_auth, u8_t seg_count)
+{
+    u32_t total = 0U;
+    int i;
+
+    if (seg_count > CONFIG_BLE_MESH_FRIEND_QUEUE_SIZE) {
+        return false;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(frnd->seg); i++) {
+        struct bt_mesh_friend_seg *seg = &frnd->seg[i];
+
+        if (seq_auth) {
+            struct net_buf *buf;
+
+            /* If there's a segment queue for this message then the
+             * space verification has already happened.
+             */
+            buf = (void *)sys_slist_peek_head(&seg->queue);
+            if (buf && BLE_MESH_ADV(buf)->addr == addr &&
+                FRIEND_ADV(buf)->seq_auth == *seq_auth) {
+                return true;
+            }
+        }
+
+        total += seg->seg_count;
+    }
+
+    /* If currently pending segments combined with this segmented message
+     * are more than the Friend Queue Size, then there's no space. This
+     * is because we don't have a mechanism of aborting already pending
+     * segmented messages to free up buffers.
+     */
+    return (CONFIG_BLE_MESH_FRIEND_QUEUE_SIZE - total) > seg_count;
+}
+
+bool bt_mesh_friend_queue_has_space(u16_t net_idx, u16_t src, u16_t dst,
+                                    u64_t *seq_auth, u8_t seg_count)
+{
+    bool someone_has_space = false, friend_match = false;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(bt_mesh.frnd); i++) {
+        struct bt_mesh_friend *frnd = &bt_mesh.frnd[i];
+
+        if (!friend_lpn_matches(frnd, net_idx, dst)) {
+            continue;
+        }
+
+        friend_match = true;
+
+        if (friend_queue_has_space(frnd, src, seq_auth, seg_count)) {
+            someone_has_space = true;
+        }
+    }
+
+    /* If there were no matched LPNs treat this as success, so the
+     * transport layer can continue its work.
+     */
+    if (!friend_match) {
+        return true;
+    }
+
+    /* From the transport layers perspective it's good enough that at
+     * least one Friend Queue has space. If there were multiple Friend
+     * matches then the destination must be a group address, in which
+     * case e.g. segment acks are not sent.
+     */
+    return someone_has_space;
+}
+
+static bool friend_queue_prepare_space(struct bt_mesh_friend *frnd, u16_t addr,
+                                       u64_t *seq_auth, u8_t seg_count)
+{
+    bool pending_segments;
+    u8_t avail_space;
+
+    if (!friend_queue_has_space(frnd, addr, seq_auth, seg_count)) {
+        return false;
+    }
+
+    avail_space = CONFIG_BLE_MESH_FRIEND_QUEUE_SIZE - frnd->queue_size;
+    pending_segments = false;
+
+    while (pending_segments || avail_space < seg_count) {
+        struct net_buf *buf = (void *)sys_slist_get(&frnd->queue);
+
+        if (!buf) {
+            BT_ERR("Unable to free up enough buffers");
+            return false;
+        }
+
+        frnd->queue_size--;
+        avail_space++;
+
+        pending_segments = (buf->flags & NET_BUF_FRAGS);
+
+        /* Make sure old slist entry state doesn't remain */
+        buf->frags = NULL;
+        buf->flags &= ~NET_BUF_FRAGS;
+
+        net_buf_unref(buf);
+    }
+
+    return true;
+}
+
 void bt_mesh_friend_enqueue_rx(struct bt_mesh_net_rx *rx,
                                enum bt_mesh_friend_pdu_type type,
-                               u64_t *seq_auth, struct net_buf_simple *sbuf)
+                               u64_t *seq_auth, u8_t seg_count,
+                               struct net_buf_simple *sbuf)
 {
     int i;
 
@@ -1248,16 +1349,25 @@ void bt_mesh_friend_enqueue_rx(struct bt_mesh_net_rx *rx,
     for (i = 0; i < ARRAY_SIZE(bt_mesh.frnd); i++) {
         struct bt_mesh_friend *frnd = &bt_mesh.frnd[i];
 
-        if (friend_lpn_matches(frnd, rx->sub->net_idx,
+        if (!friend_lpn_matches(frnd, rx->sub->net_idx,
                     rx->ctx.recv_dst)) {
-            friend_lpn_enqueue_rx(frnd, rx, type, seq_auth, sbuf);
+            continue;
         }
+
+        if (!friend_queue_prepare_space(frnd, rx->ctx.addr, seq_auth,
+                                        seg_count)) {
+            continue;
+        }
+
+        friend_lpn_enqueue_rx(frnd, rx, type, seq_auth, seg_count,
+                              sbuf);
     }
 }
 
 bool bt_mesh_friend_enqueue_tx(struct bt_mesh_net_tx *tx,
                                enum bt_mesh_friend_pdu_type type,
-                               u64_t *seq_auth, struct net_buf_simple *sbuf)
+                               u64_t *seq_auth, u8_t seg_count,
+                               struct net_buf_simple *sbuf)
 {
     bool matched = false;
     int i;
@@ -1273,10 +1383,19 @@ bool bt_mesh_friend_enqueue_tx(struct bt_mesh_net_tx *tx,
     for (i = 0; i < ARRAY_SIZE(bt_mesh.frnd); i++) {
         struct bt_mesh_friend *frnd = &bt_mesh.frnd[i];
 
-        if (friend_lpn_matches(frnd, tx->sub->net_idx, tx->ctx->addr)) {
+        if (!friend_lpn_matches(frnd, tx->sub->net_idx,
-            friend_lpn_enqueue_tx(frnd, tx, type, seq_auth, sbuf);
+                                tx->ctx->addr)) {
-            matched = true;
+            continue;
         }
+
+        if (!friend_queue_prepare_space(frnd, tx->src, seq_auth,
+                                        seg_count)) {
+            continue;
+        }
+
+        friend_lpn_enqueue_tx(frnd, tx, type, seq_auth, seg_count,
+                              sbuf);
+        matched = true;
     }
 
     return matched;
@@ -1316,9 +1435,8 @@ void bt_mesh_friend_clear_incomplete(struct bt_mesh_subnet *sub, u16_t src,
 
             BT_WARN("%s, Clearing incomplete segments for 0x%04x", __func__, src);
 
-            while (!sys_slist_is_empty(&seg->queue)) {
+            purge_buffers(&seg->queue);
-                net_buf_unref(net_buf_slist_get(&seg->queue));
+            seg->seg_count = 0U;
-            }
         }
     }
 }

components/bt/esp_ble_mesh/mesh_core/friend.h

@@ -20,12 +20,17 @@ bool bt_mesh_friend_match(u16_t net_idx, u16_t addr);
 struct bt_mesh_friend *bt_mesh_friend_find(u16_t net_idx, u16_t lpn_addr,
         bool valid, bool established);
 
+bool bt_mesh_friend_queue_has_space(u16_t net_idx, u16_t src, u16_t dst,
+                                    u64_t *seq_auth, u8_t seg_count);
+
 void bt_mesh_friend_enqueue_rx(struct bt_mesh_net_rx *rx,
                                enum bt_mesh_friend_pdu_type type,
-                               u64_t *seq_auth, struct net_buf_simple *sbuf);
+                               u64_t *seq_auth, u8_t seg_count,
+                               struct net_buf_simple *sbuf);
 bool bt_mesh_friend_enqueue_tx(struct bt_mesh_net_tx *tx,
                                enum bt_mesh_friend_pdu_type type,
-                               u64_t *seq_auth, struct net_buf_simple *sbuf);
+                               u64_t *seq_auth, u8_t seg_count,
+                               struct net_buf_simple *sbuf);
 
 void bt_mesh_friend_clear_incomplete(struct bt_mesh_subnet *sub, u16_t src,
                                      u16_t dst, u64_t *seq_auth);

components/bt/esp_ble_mesh/mesh_core/net.h

@@ -115,6 +115,12 @@ struct bt_mesh_friend {
 
     struct bt_mesh_friend_seg {
         sys_slist_t queue;
+
+        /* The target number of segments, i.e. not necessarily
+         * the current number of segments, in the queue. This is
+         * used for Friend Queue free space calculations.
+         */
+        u8_t        seg_count;
     } seg[FRIEND_SEG_RX];
 
     struct net_buf *last;

components/bt/esp_ble_mesh/mesh_core/transport.c

@@ -141,8 +141,21 @@ static int send_unseg(struct bt_mesh_net_tx *tx, struct net_buf_simple *sdu,
 
     if (IS_ENABLED(CONFIG_BLE_MESH_NODE) && bt_mesh_is_provisioned()) {
     if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND)) {
+        if (!bt_mesh_friend_queue_has_space(tx->sub->net_idx,
+                                            tx->src, tx->ctx->addr,
+                                            NULL, 1)) {
+            if (BLE_MESH_ADDR_IS_UNICAST(tx->ctx->addr)) {
+                BT_ERR("Not enough space in Friend Queue");
+                net_buf_unref(buf);
+                return -ENOBUFS;
+            } else {
+                BT_WARN("No space in Friend Queue");
+                goto send;
+            }
+        }
+
         if (bt_mesh_friend_enqueue_tx(tx, BLE_MESH_FRIEND_PDU_SINGLE,
-                                      NULL, &buf->b) &&
+                                      NULL, 1, &buf->b) &&
                 BLE_MESH_ADDR_IS_UNICAST(tx->ctx->addr)) {
             /* PDUs for a specific Friend should only go
              * out through the Friend Queue.
@@ -154,6 +167,7 @@ static int send_unseg(struct bt_mesh_net_tx *tx, struct net_buf_simple *sdu,
     }
     }
 
+send:
     return bt_mesh_net_send(tx, buf, cb, cb_data);
 }
 
@@ -365,6 +379,17 @@ static int send_seg(struct bt_mesh_net_tx *net_tx, struct net_buf_simple *sdu,
 
     BT_DBG("SeqZero 0x%04x", seq_zero);
 
+    if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND) &&
+        !bt_mesh_friend_queue_has_space(tx->sub->net_idx, net_tx->src,
+                                        tx->dst, &tx->seq_auth,
+                                        tx->seg_n + 1) &&
+        BLE_MESH_ADDR_IS_UNICAST(tx->dst)) {
+        BT_ERR("Not enough space in Friend Queue for %u segments",
+                tx->seg_n + 1);
+        seg_tx_reset(tx);
+        return -ENOBUFS;
+    }
+
     for (seg_o = 0U; sdu->len; seg_o++) {
         struct net_buf *seg;
         u16_t len;
@@ -404,6 +429,7 @@ static int send_seg(struct bt_mesh_net_tx *net_tx, struct net_buf_simple *sdu,
 
             if (bt_mesh_friend_enqueue_tx(net_tx, type,
                                           &tx->seq_auth,
+                                          tx->seg_n + 1,
                                           &seg->b) &&
                 BLE_MESH_ADDR_IS_UNICAST(net_tx->ctx->addr)) {
                 /* PDUs for a specific Friend should only go
@@ -1029,7 +1055,7 @@ int bt_mesh_ctl_send(struct bt_mesh_net_tx *tx, u8_t ctl_op, void *data,
 
     if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND)) {
         if (bt_mesh_friend_enqueue_tx(tx, BLE_MESH_FRIEND_PDU_SINGLE,
-                                      seq_auth, &buf->b) &&
+                                      seq_auth, 1, &buf->b) &&
             BLE_MESH_ADDR_IS_UNICAST(tx->ctx->addr)) {
             /* PDUs for a specific Friend should only go
              * out through the Friend Queue.
@@ -1237,7 +1263,8 @@ static struct seg_rx *seg_rx_alloc(struct bt_mesh_net_rx *net_rx,
 }
 
 static int trans_seg(struct net_buf_simple *buf, struct bt_mesh_net_rx *net_rx,
-                     enum bt_mesh_friend_pdu_type *pdu_type, u64_t *seq_auth)
+                     enum bt_mesh_friend_pdu_type *pdu_type, u64_t *seq_auth,
+                     u8_t *seg_count)
 {
     struct bt_mesh_rpl *rpl = NULL;
     struct seg_rx *rx;
@@ -1294,6 +1321,8 @@ static int trans_seg(struct net_buf_simple *buf, struct bt_mesh_net_rx *net_rx,
                           ((((net_rx->seq & BIT_MASK(14)) - seq_zero)) &
                            BIT_MASK(13))));
 
+    *seg_count = seg_n + 1;
+
     /* Look for old RX sessions */
     rx = seg_rx_find(net_rx, seq_auth);
     if (rx) {
@@ -1342,6 +1371,22 @@ static int trans_seg(struct net_buf_simple *buf, struct bt_mesh_net_rx *net_rx,
         return -EMSGSIZE;
     }
 
+    /* Verify early that there will be space in the Friend Queue(s) in
+     * case this message is destined to an LPN of ours.
+     */
+    if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND) &&
+        net_rx->friend_match && !net_rx->local_match &&
+        !bt_mesh_friend_queue_has_space(net_rx->sub->net_idx,
+                                        net_rx->ctx.addr,
+                                        net_rx->ctx.recv_dst, seq_auth,
+                                        *seg_count)) {
+        BT_ERR("No space in Friend Queue for %u segments", *seg_count);
+        send_ack(net_rx->sub, net_rx->ctx.recv_dst, net_rx->ctx.addr,
+                 net_rx->ctx.send_ttl, seq_auth, 0,
+                 net_rx->friend_match);
+        return -ENOBUFS;
+    }
+
     /* Look for free slot for a new RX session */
     rx = seg_rx_alloc(net_rx, hdr, seq_auth, seg_n);
     if (!rx) {
@@ -1436,6 +1481,7 @@ int bt_mesh_trans_recv(struct net_buf_simple *buf, struct bt_mesh_net_rx *rx)
     u64_t seq_auth = TRANS_SEQ_AUTH_NVAL;
     enum bt_mesh_friend_pdu_type pdu_type = BLE_MESH_FRIEND_PDU_SINGLE;
     struct net_buf_simple_state state;
+    u8_t seg_count = 0U;
     int err;
 
     if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND)) {
@@ -1479,8 +1525,9 @@ int bt_mesh_trans_recv(struct net_buf_simple *buf, struct bt_mesh_net_rx *rx)
             return 0;
         }
 
-        err = trans_seg(buf, rx, &pdu_type, &seq_auth);
+        err = trans_seg(buf, rx, &pdu_type, &seq_auth, &seg_count);
     } else {
+        seg_count = 1U;
         err = trans_unseg(buf, rx, &seq_auth);
     }
 
@@ -1508,9 +1555,11 @@ int bt_mesh_trans_recv(struct net_buf_simple *buf, struct bt_mesh_net_rx *rx)
     if (IS_ENABLED(CONFIG_BLE_MESH_NODE) && bt_mesh_is_provisioned()) {
     if (IS_ENABLED(CONFIG_BLE_MESH_FRIEND) && rx->friend_match && !err) {
         if (seq_auth == TRANS_SEQ_AUTH_NVAL) {
-            bt_mesh_friend_enqueue_rx(rx, pdu_type, NULL, buf);
+            bt_mesh_friend_enqueue_rx(rx, pdu_type, NULL,
+                                      seg_count, buf);
         } else {
-            bt_mesh_friend_enqueue_rx(rx, pdu_type, &seq_auth, buf);
+            bt_mesh_friend_enqueue_rx(rx, pdu_type, &seq_auth,
+                                      seg_count, buf);
         }
     }
     }