From fdadfe279cd9a090ee5601402013fdf4f1712e40 Mon Sep 17 00:00:00 2001
From: Hauke Petersen <hauke.petersen@fu-berlin.de>
Date: Tue, 16 May 2017 16:24:48 +0200
Subject: [PATCH] net: added link layer address filter module
---
Makefile.dep | 4 +
makefiles/pseudomodules.inc.mk | 2 +
sys/Makefile | 3 +
sys/include/net/l2filter.h | 129 +++++++++++++++++++++++++
sys/net/link_layer/l2filter/Makefile | 1 +
sys/net/link_layer/l2filter/l2filter.c | 107 ++++++++++++++++++++
6 files changed, 246 insertions(+)
create mode 100644 sys/include/net/l2filter.h
create mode 100644 sys/net/link_layer/l2filter/Makefile
create mode 100644 sys/net/link_layer/l2filter/l2filter.c
diff --git a/Makefile.dep b/Makefile.dep
index 4cb063dc9c..bff528ba0b 100644
--- a/Makefile.dep
+++ b/Makefile.dep
@@ -594,6 +594,10 @@ ifneq (,$(filter spiffs,$(USEMODULE)))
USEMODULE += mtd
endif
+ifneq (,$(filter l2filter_%,$(USEMODULE)))
+ USEMODULE += l2filter
+endif
+
# include package dependencies
-include $(USEPKG:%=$(RIOTPKG)/%/Makefile.dep)
diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
index d922c62116..990b5eda6a 100644
--- a/makefiles/pseudomodules.inc.mk
+++ b/makefiles/pseudomodules.inc.mk
@@ -17,6 +17,8 @@ PSEUDOMODULES += gnrc_sixlowpan_router
PSEUDOMODULES += gnrc_sixlowpan_router_default
PSEUDOMODULES += gnrc_sock_check_reuse
PSEUDOMODULES += gnrc_txtsnd
+PSEUDOMODULES += l2filter_blacklist
+PSEUDOMODULES += l2filter_whitelist
PSEUDOMODULES += log
PSEUDOMODULES += log_printfnoformat
PSEUDOMODULES += lwip_arp
diff --git a/sys/Makefile b/sys/Makefile
index 206985f5c1..143b65e2b1 100644
--- a/sys/Makefile
+++ b/sys/Makefile
@@ -125,6 +125,9 @@ endif
ifneq (,$(filter devfs,$(USEMODULE)))
DIRS += fs/devfs
endif
+ifneq (,$(filter l2filter,$(USEMODULE)))
+ DIRS += net/link_layer/l2filter
+endif
DIRS += $(dir $(wildcard $(addsuffix /Makefile, ${USEMODULE})))
diff --git a/sys/include/net/l2filter.h b/sys/include/net/l2filter.h
new file mode 100644
index 0000000000..3e6403ebc8
--- /dev/null
+++ b/sys/include/net/l2filter.h
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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_l2filter Link layer address filter
+ * @ingroup net
+ * @brief Module for filtering (black- or white-listing) link layer
+ * addresses
+ *
+ * This module is used as a base for filtering link layer addresses. It allows
+ * to be (globally) configured in either blacklist or in whitelist mode. This
+ * configuration is done via RIOTs module system, for whitelist mode simply
+ * include the module `L2FILTER_WHITELIST`, for blacklist mode include
+ * `L2FILTER_BLACKLIST`.
+ *
+ * The actual memory for the filter lists should be allocated for every network
+ * device. This is done centrally in netdev_t type.
+ *
+ * @{
+ * @file
+ * @brief Link layer address filter interface definition
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef L2FILTER_H
+#define L2FILTER_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Maximal length of addresses that can be stored in the filter list
+ */
+#ifndef L2FILTER_ADDR_MAXLEN
+#define L2FILTER_ADDR_MAXLEN (8U)
+#endif
+
+/**
+ * @brief Number of slots in each filter list (filter entries per device)
+ */
+#ifndef L2FILTER_LISTSIZE
+#define L2FILTER_LISTSIZE (8U)
+#endif
+
+/**
+ * @brief Filter list entries
+ *
+ * The filter list supports address entries with differing length. This is
+ * useful e.g. for IEEE802.15.4, where the list can store short and long
+ * addresses at the same time.
+ */
+typedef struct {
+ uint8_t addr[L2FILTER_ADDR_MAXLEN]; /**< link layer address */
+ size_t addr_len; /**< address length in byte */
+} l2filter_t;
+
+/**
+ * @brief Add an entry to a devices filter list
+ *
+ * @param[in,out] list pointer to the filter list
+ * @param[in] addr address to be added to list
+ * @param[in] addr_len size of @p addr [in byte]
+ *
+ * @pre @p list != NULL
+ * @pre @p addr != NULL
+ * @pre @p addr_maxlen <= @ref L2FILTER_ADDR_MAXLEN
+ *
+ * @return 0 on success
+ * @return -ENOMEM if no empty slot left in list
+ */
+int l2filter_add(l2filter_t *list, const void *addr, size_t addr_len);
+
+/**
+ * @brief Remove an entry from the given filter list
+ *
+ * @param[in,out] list pointer to the filter list
+ * @param[in] addr address to remove from the list
+ * @param[in] addr_len length of @p addr [in byte]
+ *
+ * @pre @p list != NULL
+ * @pre @p addr != NULL
+ * @pre @p addr_maxlen <= @ref L2FILTER_ADDR_MAXLEN
+ *
+ * @return 0 on success
+ * @return -ENOENT if @p addr was not found in @p list
+ */
+int l2filter_rm(l2filter_t *list, const void *addr, size_t addr_len);
+
+/**
+ * @brief Check if the given address passes the set filters
+ *
+ * Independent if the l2filter module is used in blacklist or in whitelist mode,
+ * this function returns whether the given address passes the filter. In
+ * whitelist mode, this means that the given address has to be in the list, in
+ * blacklist mode this means that the given address is not in the list.
+ *
+ * @param[in] list list with black-/whitelisted addresses
+ * @param[in] addr address to check against the entries in @p list
+ * @param[in] addr_len length of @p addr [in byte]
+ *
+ * @pre @p list != NULL
+ * @pre @p addr != NULL
+ * @pre @p addr_maxlen <= @ref L2FILTER_ADDR_MAXLEN
+ *
+ * @return in whitelist mode: true if @p addr is in @p list
+ * @return in whitelist mode: false if @p addr is not in @p list
+ * @return in blacklist mode: true if @p addr is not in @p list
+ * @return in blacklist mode: false if @p addr is in @p list
+ */
+bool l2filter_pass(const l2filter_t *list, const void *addr, size_t addr_len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* L2FILTER_H */
+/** @} */
diff --git a/sys/net/link_layer/l2filter/Makefile b/sys/net/link_layer/l2filter/Makefile
new file mode 100644
index 0000000000..48422e909a
--- /dev/null
+++ b/sys/net/link_layer/l2filter/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/sys/net/link_layer/l2filter/l2filter.c b/sys/net/link_layer/l2filter/l2filter.c
new file mode 100644
index 0000000000..b9a50e3d55
--- /dev/null
+++ b/sys/net/link_layer/l2filter/l2filter.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * 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_l2filter
+ * @{
+ *
+ * @file
+ * @brief Link layer address filter implementation
+ *
+ * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <string.h>
+
+#include "assert.h"
+#include "net/l2filter.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+static inline bool match(const l2filter_t *filter,
+ const void *addr, size_t addr_len)
+{
+ return ((filter->addr_len == addr_len) &&
+ (memcmp(filter->addr, addr, addr_len) == 0));
+}
+
+void l2filter_init(l2filter_t *list)
+{
+ assert(list);
+
+ for (unsigned i = 0; i < L2FILTER_LISTSIZE; i++) {
+ list[i].addr_len = 0;
+ }
+}
+
+int l2filter_add(l2filter_t *list, const void *addr, size_t addr_len)
+{
+ assert(list && addr && (addr_len <= L2FILTER_ADDR_MAXLEN));
+
+ int res = -ENOMEM;
+
+ for (unsigned i = 0; i < L2FILTER_LISTSIZE; i++) {
+ if (list[i].addr_len == 0) {
+ list[i].addr_len = addr_len;
+ memcpy(list[i].addr, addr, addr_len);
+ res = 0;
+ break;
+ }
+ }
+
+ return res;
+}
+
+int l2filter_rm(l2filter_t *list, const void *addr, size_t addr_len)
+{
+ assert(list && addr && (addr_len <= L2FILTER_ADDR_MAXLEN));
+
+ int res = -ENOENT;
+
+ for (unsigned i = 0; i < L2FILTER_LISTSIZE; i++) {
+ if (match(&list[i], addr, addr_len)) {
+ list[i].addr_len = 0;
+ res = 0;
+ break;
+ }
+ }
+
+ return res;
+}
+
+bool l2filter_pass(const l2filter_t *list, const void *addr, size_t addr_len)
+{
+ assert(list && addr && (addr_len <= L2FILTER_ADDR_MAXLEN));
+
+#ifdef MODULE_L2FILTER_WHITELIST
+ bool res = false;
+ for (unsigned i = 0; i < L2FILTER_LISTSIZE; i++) {
+ if (match(&list[i], addr, addr_len)) {
+ DEBUG("[l2filter] whitelist: address match -> packet passes\n");
+ res = true;
+ break;
+ }
+ }
+ DEBUG("[l2filter] whitelist: no match -> packet dropped\n");
+#else
+ bool res = true;
+ for (unsigned i = 0; i < L2FILTER_LISTSIZE; i++) {
+ if (match(&list[i], addr, addr_len)) {
+ DEBUG("[l2filter] blacklist: address match -> packet dropped\n");
+ res = false;
+ break;
+ }
+ }
+ DEBUG("[l2fitler] blacklist: no match -> packet passes\n");
+#endif
+
+ return res;
+}
--
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