sys/net: add l2scan list module

sys/Makefile

@@ -101,6 +101,9 @@ endif
 ifneq (,$(filter l2filter,$(USEMODULE)))
   DIRS += net/link_layer/l2filter
 endif
+ifneq (,$(filter l2scan_list,$(USEMODULE)))
+  DIRS += net/link_layer/l2scan_list
+endif
 ifneq (,$(filter l2util,$(USEMODULE)))
   DIRS += net/link_layer/l2util
 endif

sys/include/net/l2scan_list.h

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2023 ML!PA Consulting Gmbh
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    net_l2scanlist   Scan List - List of wireless access points
+ * @ingroup     net
+ * @brief       Internal list data structure of scanned access points
+ *              @ref NETOPT_SCAN
+ * @{
+ *
+ * @file
+ * @brief       L2 Scan list API
+ *
+ * @author      Fabian Hüßler <fabian.huessler@ml-pa.com>
+ */
+
+#ifndef NET_L2SCAN_LIST_H
+#define NET_L2SCAN_LIST_H
+
+#include <stdlib.h>
+
+#include "list.h"
+#include "net/netopt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Type of a Link Layer scan list
+ */
+typedef struct l2scan_list {
+    list_node_t *head;          /**< Pointer to the list head node */
+    /* items */
+} l2scan_list_t;
+
+/**
+ * @brief   Empty the list to start a new scan
+ *
+ * @param[in, out]  list            Pointer to list
+ * @param[in, out]  nodes           Pointer to nodes array
+ * @param[in]       nodes_numof     Number of nodes in the array
+ * @param[in]       node_size       Size of one node element in the array
+ */
+void l2scan_list_empty(l2scan_list_t *list,
+                       list_node_t *nodes, unsigned nodes_numof,
+                       size_t node_size);
+
+/**
+ * @brief   Insert a new scan result into the list
+ *
+ * @param[in, out]  list            Pointer to list
+ * @param[in, out]  nodes           Pointer to nodes array
+ * @param[in]       nodes_numof     Number of nodes in the array
+ * @param[in]       node_size       Size of one node element in the array
+ * @param[in]       result          New result to insert
+ */
+void l2scan_list_insert(l2scan_list_t *list,
+                        list_node_t *nodes, unsigned nodes_numof,
+                        size_t node_size,
+                        const netopt_scan_result_t *result);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NET_L2SCAN_LIST_H */
+/** @} */

sys/net/link_layer/l2scan_list/Kconfig

@@ -0,0 +1,9 @@
+# Copyright (c) 2023 ML!PA Consulting Gmbh
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+
+config MODULE_L2SCAN_LIST
+    bool "List of scanned Link Layer access points"

sys/net/link_layer/l2scan_list/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

sys/net/link_layer/l2scan_list/l2scan_list.c

@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2023 ML!PA Consulting Gmbh
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     net_l2scan_list
+ * @{
+ *
+ * @file
+ * @brief       List to store the result of a network scan
+ *
+ * @author      Fabian Hüßler <fabian.huessler@ml-pa.com>
+ *
+ * @}
+ */
+
+#include <string.h>
+
+#include "list.h"
+#include "net/netopt.h"
+#include "net/l2scan_list.h"
+
+#define SCAN_LIST_NODE_AT(array, pos, size) ((void *)(((uint8_t *)(array)) + ((pos) * (size))))
+
+/**
+ * @brief  Basic type of a scan result in a list
+ */
+typedef struct scan_list_node {
+    list_node_t node;               /* Basic node */
+    netopt_scan_result_t result;    /* Basic scan result */
+} scan_list_node_t;
+
+static scan_list_node_t *_scan_list_get_insert(l2scan_list_t *list,
+                                               list_node_t *array, unsigned array_numof,
+                                               size_t item_size)
+{
+    scan_list_node_t *lowest = (scan_list_node_t *)array;
+    for (unsigned i = 0; i < array_numof; i++) {
+        /* look for free slot or lowest element */
+        scan_list_node_t *result = SCAN_LIST_NODE_AT(array, i, item_size);
+        if (!result->result.strength) {
+            return result; /* free slot */
+        }
+        if (result->result.strength < lowest->result.strength) {
+            lowest = result; /* override lowest element */
+        }
+    }
+    list_node_t l = { .next = list->head };
+    list_remove(&l, &lowest->node);
+    return lowest;
+}
+
+void l2scan_list_empty(l2scan_list_t *list,
+                       list_node_t *nodes, unsigned nodes_numof,
+                       size_t node_size)
+{
+    list->head = NULL;
+    memset(nodes, 0, nodes_numof * node_size);
+}
+
+void l2scan_list_insert(l2scan_list_t *list,
+                        list_node_t *nodes, unsigned nodes_numof,
+                        size_t node_size,
+                        const netopt_scan_result_t *result)
+{
+    scan_list_node_t *insert = _scan_list_get_insert(list, nodes,
+                                                     nodes_numof, node_size);
+    *insert = (scan_list_node_t) { .node = { .next = NULL }, };
+    memcpy(&insert->result, result, node_size - sizeof(list_node_t));
+
+    if (!list->head) {
+        list->head = &insert->node;
+    }
+    else if (((scan_list_node_t *)list->head)->result.strength < result->strength) {
+        insert->node.next = list->head;
+        list->head = &insert->node;
+    }
+    else {
+        scan_list_node_t *next, *before = (scan_list_node_t *)list->head;
+        while ((next = (scan_list_node_t *)before->node.next) &&
+               next->result.strength > result->strength) {
+            before = (scan_list_node_t *)before->node.next;
+        }
+        list_add(&before->node, &insert->node);
+    }
+}