sixlowpan.iphc_cbuf: Initial import of an IPHC context buffer

Makefile.dep

@@ -47,6 +47,10 @@ ifneq (,$(filter sixlowpan_legacy,$(USEMODULE)))
 	USEMODULE += vtimer
 endif
 
+ifneq (,$(filter sixlowpan_iphc_cbuf,$(USEMODULE)))
+	USEMODULE += vtimer
+endif
+
 ifneq (,$(filter sixlowpan,$(USEMODULE)))
 	USEMODULE += netapi
 	USEMODULE += netdev_base

sys/Makefile

@@ -44,6 +44,9 @@ endif
 ifneq (,$(filter sixlowpan,$(USEMODULE)))
     DIRS += net/link_layer/sixlowpan
 endif
+ifneq (,$(filter sixlowpan_iphc_cbuf,$(USEMODULE)))
+    DIRS += net/link_layer/sixlowpan/iphc_cbuf
+endif
 ifneq (,$(filter ipv6,$(USEMODULE)))
     # TODO
 endif

sys/Makefile.include

@@ -34,6 +34,9 @@ endif
 ifneq (,$(filter sixlowpan_legacy,$(USEMODULE)))
     USEMODULE_INCLUDES += $(RIOTBASE)/sys/net/include
 endif
+ifneq (,$(filter sixlowpan_iphc_cbuf,$(USEMODULE)))
+    USEMODULE_INCLUDES += $(RIOTBASE)/sys/net/include
+endif
 ifneq (,$(filter rpl,$(USEMODULE)))
     USEMODULE_INCLUDES += $(RIOTBASE)/sys/net/include
     USEMODULE_INCLUDES += $(RIOTBASE)/sys/net/routing/rpl

sys/net/include/sixlowpan/iphc_cbuf.h

@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2014 Martin Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * 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_sixlowpan_iphc_cbuf Context buffer for 6LoWPAN IP header compression
+ * @addtogroup  net_sixlowpan
+ * @{
+ *
+ * @file        iphc_cbuf.h
+ * @brief       Context buffer for 6LoWPAN IP header compression
+ *
+ * @see         <a href="https://tools.ietf.org/html/rfc6282#section-3.1.2">
+ *                  RFC 6282, section 3.1.2
+ *              </a>
+ * @see         <a href="http://tools.ietf.org/html/rfc6775#section-4.2">
+ *                  RFC 6775, section 4.2
+ *              </a>
+ *
+ * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+
+
+#ifndef __SIXLOWPAN_IPHC_CBUF_H_
+#define __SIXLOWPAN_IPHC_CBUF_H_
+
+#include "ipv6.h"
+
+#define SIXLOWPAN_IPHC_CBUF_SIZE (16)
+
+/**
+ * @brief   Data type to configure 6LoWPAN contexts
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1">
+ *          RFC 6282, section 3.1
+ *      </a>
+ */
+typedef struct {
+    uint8_t cid;            /**< Context ID */
+    uint8_t prefix_len;     /**< Length of the prefix in bits, if 0 on
+                                 NETAPI_CMD_SET the context will be removed. */
+    ipv6_addr_t prefix;     /**< The prefix associated to this context */
+
+    /**
+     * @brief   Lifetime in minutes this context is valid.
+     *
+     * @see     <a href="http://tools.ietf.org/html/rfc6775#section-4.2">
+     *              6LoWPAN Context Option
+     *          </a>
+     */
+    uint32_t lifetime;
+} sixlowpan_iphc_cbuf_t;
+
+/**
+ * @brief   Lookup best context for an IPv6 address.
+ *
+ * @param[in] addr      An IPv6 address.
+ *
+ * @return  best fitting context for given IPv6 address.
+ * @return  NULL, if no fitting context can be found.
+ */
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_lookup_addr(const ipv6_addr_t *addr);
+
+/**
+ * @brief   Lookup best context for a context ID.
+ *
+ * @param[in] cid       A context ID, must be < 16.
+ *
+ * @return  best fitting context for given context ID.
+ * @return  NULL, if no fitting context can be found.
+ */
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_lookup_cid(uint8_t cid);
+
+/**
+ * @brief   Returns number of currently saved contexts.
+ *
+ * @return  Number of currently saved contexts.
+ */
+uint8_t sixlowpan_iphc_cbuf_num(void);
+
+/**
+ * @brief   Remove context by context ID.
+
+ * @param[in] cid       A context ID, must be < 16.
+ */
+void sixlowpan_iphc_cbuf_remove_by_cid(uint8_t cid);
+
+/**
+ * @brief   Remove context by best address match.
+ *
+ * @param[in] addr  An IPv6 address.
+ */
+static inline void sixlowpan_iphc_cbuf_remove_by_addr(const ipv6_addr_t *addr)
+{
+    sixlowpan_iphc_cbuf_t *context = sixlowpan_iphc_cbuf_lookup_addr(addr);
+
+    if (context) {
+        sixlowpan_iphc_cbuf_remove_by_cid(context->cid);
+    }
+}
+
+/**
+ * @brief   Removes all context with expired lifetime
+ */
+void sixlowpan_iphc_cbuf_remove_invalid(void);
+
+/**
+ * @brief   Update a context
+ *
+ * @param[in] cid           A context ID, must be < 16.
+ * @param[in] prefix        An IPv6 prefix to associate with *cid*.
+ * @param[in] prefix_len    Length of prefix in bits. If *prefix_len* is longer
+ *                          then 128, it will be set to 128. Must be > 0.
+ * @param[in] lifetime      Lifetime the context is valid in minutes. Must be > 0.
+ *
+ * @return  The updated context on success.
+ * @return  NULL, if cid is >= 16, prefix_len is 0, or lifetime is 0.
+ */
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_update(uint8_t cid, const ipv6_addr_t *prefix,
+        uint8_t prefix_len, uint16_t lifetime);
+
+#endif /* __SIXLOWPAN_IPHC_CBUF_H_ */
+/**
+ * @}
+ */

sys/net/link_layer/sixlowpan/iphc_cbuf/Makefile

@@ -0,0 +1,3 @@
+MODULE = sixlowpan_iphc_cbuf
+
+include $(RIOTBASE)/Makefile.base

sys/net/link_layer/sixlowpan/iphc_cbuf/iphc_cbuf.c

@@ -0,0 +1,227 @@
+/*
+ * Copyright (C) 2014 Martin Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * 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.
+ */
+
+/**
+ * @addtogroup  net_sixlowpan_iphc_cbuf
+ * @{
+ *
+ * @file        iphc_cbuf.c
+ *
+ * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+
+#include <string.h>
+
+#include "mutex.h"
+#include "vtimer.h"
+
+#include "ipv6.h"
+#include "sixlowpan/iphc_cbuf.h"
+
+static sixlowpan_iphc_cbuf_t _cbuf[SIXLOWPAN_IPHC_CBUF_SIZE];
+static uint32_t _cbuf_invalid_time[SIXLOWPAN_IPHC_CBUF_SIZE];
+static mutex_t _cbuf_mutex = MUTEX_INIT;
+
+#ifndef MODULE_IPV6
+void ipv6_addr_init_prefix(ipv6_addr_t *out, const ipv6_addr_t *prefix,
+                           uint8_t bits)
+{
+    if (bits > 128) {
+        bits = 128;
+    }
+
+    uint8_t bytes = bits / 8, mask;
+
+    if (bits % 8) {
+        mask = 0xff << (8 - (bits - (bytes * 8)));
+    }
+    else {
+        mask = 0x00;
+    }
+
+    memcpy(out, prefix, bytes);
+    out->u8[bytes] = prefix->u8[bytes] & mask;
+    memset(&(out[bytes + 1]), 0, 15 - bytes);
+}
+#endif /* MODULE_IPV6 */
+
+static uint32_t _now_in_minutes(void)
+{
+    timex_t now;
+
+    vtimer_now(&now);
+
+    return now.seconds / 60;
+}
+
+static void _cid_update_lifetime(uint8_t cid)
+{
+    uint32_t now = _now_in_minutes();
+#ifdef DEVELHELP
+
+    if (cid >= SIXLOWPAN_IPHC_CBUF_SIZE) {
+        return;
+    }
+
+#endif
+
+    if (now >= _cbuf_invalid_time[cid]) {
+        _cbuf[cid].lifetime = 0;
+    }
+    else {
+        _cbuf[cid].lifetime = _cbuf_invalid_time[cid] - now;
+    }
+}
+
+static int _cid_still_valid(uint8_t cid)
+{
+#ifdef DEVELHELP
+
+    if (cid >= SIXLOWPAN_IPHC_CBUF_SIZE) {
+        return 0;
+    }
+
+#endif
+    _cid_update_lifetime(cid);
+
+    return (_cbuf[cid].lifetime > 0);
+}
+
+void _iphc_cbuf_internal_remove(uint8_t cid)
+{
+    if (cid < SIXLOWPAN_IPHC_CBUF_SIZE) {
+        _cbuf[cid].cid = 0;
+        _cbuf[cid].prefix_len = 0;
+        memset(&(_cbuf[cid].prefix), 0, sizeof(ipv6_addr_t));
+        _cbuf[cid].lifetime = 0;
+        _cbuf_invalid_time[cid] = 0;
+    }
+}
+
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_lookup_addr(const ipv6_addr_t *addr)
+{
+    sixlowpan_iphc_cbuf_t *c = NULL;
+    uint8_t bytes;
+
+    mutex_lock(&_cbuf_mutex);
+
+    for (int i = 0; i < SIXLOWPAN_IPHC_CBUF_SIZE; i++) {
+        bytes = _cbuf[i].prefix_len / 8;
+
+        if (_cbuf[i].prefix_len > 0 && memcmp(addr, &(_cbuf[i].prefix), bytes) == 0) {
+            if (_cbuf[i].prefix_len % 8) {
+                uint8_t mask = 0xff << (8 - (_cbuf[i].prefix_len - (bytes * 8)));
+
+                if ((addr->u8[bytes] & mask) != (_cbuf[i].prefix.u8[bytes] & mask)) {
+                    continue;
+                }
+            }
+
+            if (_cid_still_valid(i)) {
+                if (c == NULL || c->prefix_len < _cbuf[i].prefix_len) {
+                    c = &_cbuf[i];
+                }
+            }
+            else {
+                _iphc_cbuf_internal_remove(i);
+            }
+        }
+    }
+
+    mutex_unlock(&_cbuf_mutex);
+
+    return c;
+}
+
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_lookup_cid(uint8_t cid)
+{
+    sixlowpan_iphc_cbuf_t *c = NULL;
+
+    if (cid >= SIXLOWPAN_IPHC_CBUF_SIZE) {
+        return NULL;
+    }
+
+    mutex_lock(&_cbuf_mutex);
+
+    if (_cid_still_valid(cid)) {
+        c = &(_cbuf[cid]);
+    }
+    else {
+        _iphc_cbuf_internal_remove(cid);
+    }
+
+    mutex_unlock(&_cbuf_mutex);
+
+    return c;
+}
+
+uint8_t sixlowpan_iphc_cbuf_num(void)
+{
+    uint8_t num = 0;
+
+    mutex_lock(&_cbuf_mutex);
+
+    for (int i = 0; i < SIXLOWPAN_IPHC_CBUF_SIZE; i++) {
+        if (_cid_still_valid(i) && _cbuf[i].prefix_len > 0) {
+            num++;
+        }
+        else {
+            _iphc_cbuf_internal_remove(i);
+        }
+    }
+
+    mutex_unlock(&_cbuf_mutex);
+
+    return num;
+}
+
+void sixlowpan_iphc_cbuf_remove_by_cid(uint8_t cid)
+{
+    mutex_lock(&_cbuf_mutex);
+    _iphc_cbuf_internal_remove(cid);
+    mutex_unlock(&_cbuf_mutex);
+}
+
+void sixlowpan_iphc_cbuf_remove_invalid(void)
+{
+    mutex_lock(&_cbuf_mutex);
+
+    for (int i = 0; i < SIXLOWPAN_IPHC_CBUF_SIZE; i++) {
+        if (!_cid_still_valid(i)) {
+            _iphc_cbuf_internal_remove(i);
+        }
+    }
+
+    mutex_unlock(&_cbuf_mutex);
+}
+
+sixlowpan_iphc_cbuf_t *sixlowpan_iphc_cbuf_update(uint8_t cid, const ipv6_addr_t *prefix,
+        uint8_t prefix_len, uint16_t lifetime)
+{
+    sixlowpan_iphc_cbuf_t *c = NULL;
+
+    mutex_lock(&_cbuf_mutex);
+
+    if (cid < SIXLOWPAN_IPHC_CBUF_SIZE && prefix_len > 0 && lifetime > 0) {
+        _cbuf[cid].cid = cid;
+        _cbuf[cid].prefix_len = (prefix_len < IPV6_ADDR_BIT_LEN) ? prefix_len : IPV6_ADDR_BIT_LEN;
+        _cbuf[cid].lifetime = lifetime;
+        ipv6_addr_init_prefix(&(_cbuf[cid].prefix), prefix, prefix_len);
+        _cbuf_invalid_time[cid] = _now_in_minutes() + lifetime;
+
+        c = &(_cbuf[cid]);
+    }
+
+    mutex_unlock(&_cbuf_mutex);
+
+    return c;
+}
+
+/**
+ * @}
+ */