gnrc_sixlowpan_frag: initial import of the VRB

VRB = virtual reassembly buffer

sys/include/net/gnrc/sixlowpan/config.h

@@ -115,6 +115,37 @@ extern "C" {
 #define GNRC_SIXLOWPAN_ND_AR_LTIME          (15U)
 #endif
 
+/**
+ * @brief   Size of the virtual reassembly buffer
+ *
+ * @see     https://tools.ietf.org/html/draft-ietf-lwig-6lowpan-virtual-reassembly-01
+ *
+ * @note    Only applicable with
+ *          [gnrc_sixlowpan_frag_vrb](@ref net_gnrc_sixlowpan_frag_vrb) module,
+ *          but has also a direct influence on the number of available
+ *          gnrc_sixlowpan_rbuf_int_t entries (even when
+ *          `gnrc_sixlowpan_frag_vrb` is not compiled in).
+ */
+#ifndef GNRC_SIXLOWPAN_FRAG_VRB_SIZE
+#if defined(MODULE_GNRC_SIXLOWPAN_FRAG_VRB) || defined(DOXYGEN)
+#define GNRC_SIXLOWPAN_FRAG_VRB_SIZE        (16U)
+#else   /* defined(MODULE_GNRC_SIXLOWPAN_FRAG_VRB) || defined(DOXYGEN) */
+#define GNRC_SIXLOWPAN_FRAG_VRB_SIZE        (0U)
+#endif  /* defined(MODULE_GNRC_SIXLOWPAN_FRAG_VRB) || defined(DOXYGEN) */
+#endif  /* GNRC_SIXLOWPAN_FRAG_VRB_SIZE */
+
+/**
+ * @brief   Timeout for a VRB entry in microseconds
+ *
+ * @see     https://tools.ietf.org/html/draft-ietf-lwig-6lowpan-virtual-reassembly-01
+ *
+ * @note    Only applicable with
+ *          [gnrc_sixlowpan_frag_vrb](@ref net_gnrc_sixlowpan_frag_vrb) module.
+ */
+#ifndef GNRC_SIXLOWPAN_FRAG_VRB_TIMEOUT_US
+#define GNRC_SIXLOWPAN_FRAG_VRB_TIMEOUT_US  (GNRC_SIXLOWPAN_FRAG_RBUF_TIMEOUT_US)
+#endif  /* GNRC_SIXLOWPAN_FRAG_VRB_TIMEOUT_US */
+
 #ifdef __cplusplus
 }
 #endif

sys/include/net/gnrc/sixlowpan/frag/vrb.h

@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2019 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_gnrc_sixlowpan_frag_vrb Virtual reassembly buffer
+ * @ingroup     net_gnrc_sixlowpan_frag
+ * @brief       Virtual reassembly buffer
+ * @{
+ *
+ * @file
+ * @brief       Virtual reassembly buffer definitions
+ * @see         https://tools.ietf.org/html/draft-ietf-lwig-6lowpan-virtual-reassembly-01
+ *
+ * @author      Martine Lenders <m.lenders@fu-berlin.de>
+ */
+#ifndef NET_GNRC_SIXLOWPAN_FRAG_VRB_H
+#define NET_GNRC_SIXLOWPAN_FRAG_VRB_H
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "net/gnrc/netif.h"
+#include "net/gnrc/sixlowpan/config.h"
+#include "net/gnrc/sixlowpan/frag.h"
+#include "timex.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Representation of the virtual reassembly buffer entry
+ */
+typedef struct {
+    gnrc_sixlowpan_rbuf_base_t super;   /**< base type */
+
+    /**
+     * @brief   Link-layer destination address to which the fragments are
+     *          supposed to be forwarded to
+     */
+    uint8_t out_dst[IEEE802154_LONG_ADDRESS_LEN];
+    /**
+     * @brief   Outgoing interface to gnrc_sixlowpan_frag_vrb_t::out_dst
+     */
+    gnrc_netif_t *out_netif;
+    /**
+     * @brief   Outgoing tag to gnrc_sixlowpan_frag_vrb_t::out_dst
+     */
+    uint16_t out_tag;
+    /**
+     * @brief   Length of gnrc_sixlowpan_frag_vrb_t::out_dst
+     */
+    uint8_t out_dst_len;
+} gnrc_sixlowpan_frag_vrb_t;
+
+/**
+ * @brief   Adds a new reassembly buffer entry
+ *
+ * @param[in] base          Base data of the datagram. Must not be `NULL`.
+ * @param[in] out_netif     Network interface that is out-going to @p out_dst.
+ * @param[in] out_dst       Link-layer destination address to which to forward
+ *                          fragments identified by @p base. Must not be `NULL`.
+ * @param[in] out_dst_len   Length of @p out_dst. Must be greater than 0.
+ *
+ * @pre `base != NULL`
+ * @pre `out_dst != NULL`
+ * @pre `out_dst_len > 0`
+ *
+ * @return  A new VRB entry.
+ * @return  NULL, if VRB is full.
+ */
+gnrc_sixlowpan_frag_vrb_t *gnrc_sixlowpan_frag_vrb_add(
+        const gnrc_sixlowpan_rbuf_base_t *base,
+        gnrc_netif_t *out_netif, const uint8_t *out_dst, size_t out_dst_len);
+
+/**
+ * @brief   Checks timeouts and removes entries if necessary
+ */
+void gnrc_sixlowpan_frag_vrb_gc(void);
+
+/**
+ * @brief   Gets a VRB entry
+ *
+ * @param[in] src           Link-layer source address of the original fragment.
+ * @param[in] src_len       Length of @p src.
+ * @param[in] dst           Link-layer destination address of the original
+ *                          fragment.
+ * @param[in] dst_len       Length of @p dst.
+ * @param[in] datagram_size The original fragment's datagram size.
+ * @param[in] src_tag       Tag of the original fragment.
+ *
+ * @return  The VRB entry identified by the given parameters.
+ * @return  NULL, if there is no entry in the VRB that could be identified
+ *          by the given parameters.
+ */
+gnrc_sixlowpan_frag_vrb_t *gnrc_sixlowpan_frag_vrb_get(
+        const uint8_t *src, size_t src_len,
+        const uint8_t *dst, size_t dst_len,
+        size_t datagram_size, unsigned src_tag);
+
+/**
+ * @brief   Removes an entry from the VRB
+ *
+ * @param[in] vrb   A VRB entry
+ */
+static inline void gnrc_sixlowpan_frag_vrb_rm(gnrc_sixlowpan_frag_vrb_t *vrb)
+{
+#ifdef MODULE_GNRC_SIXLOWPAN_FRAG
+    gnrc_sixlowpan_frag_rbuf_base_rm(&vrb->super);
+#elif   defined(TEST_SUITES)
+    /* for testing just zero datagram_size */
+    vrb->super.datagram_size = 0;
+#endif  /* MODULE_GNRC_SIXLOWPAN_FRAG */
+}
+
+/**
+ * @brief   Determines if a VRB entry is empty
+ *
+ * @param[in] vrb   A VRB entry
+ *
+ * @return  true, if @p vrb entry is empty.
+ * @return  false, if @p vrb entry is not empty.
+ */
+static inline bool gnrc_sixlowpan_frag_vrb_entry_empty(gnrc_sixlowpan_frag_vrb_t *vrb)
+{
+    return (vrb->super.datagram_size == 0);
+}
+
+#if defined(TEST_SUITES) || defined(DOXYGEN)
+/**
+ * @brief   Resets the VRB to a clean state
+ *
+ * @note    Only available when @ref TEST_SUITES is defined
+ */
+void gnrc_sixlowpan_frag_vrb_reset(void);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NET_GNRC_SIXLOWPAN_FRAG_VRB_H */
+/** @} */

sys/net/gnrc/Makefile

@@ -88,6 +88,9 @@ endif
 ifneq (,$(filter gnrc_sixlowpan_frag,$(USEMODULE)))
   DIRS += network_layer/sixlowpan/frag
 endif
+ifneq (,$(filter gnrc_sixlowpan_frag_vrb,$(USEMODULE)))
+  DIRS += network_layer/sixlowpan/frag/vrb
+endif
 ifneq (,$(filter gnrc_sixlowpan_iphc,$(USEMODULE)))
   DIRS += network_layer/sixlowpan/iphc
 endif

sys/net/gnrc/network_layer/sixlowpan/frag/gnrc_sixlowpan_frag.c

@@ -358,7 +358,7 @@ void gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(gnrc_sixlowpan_rbuf_t *rbuf
 {
     assert(rbuf);
     assert(netif_hdr);
-    if (rbuf->super.current_size == rbuf->pkt->size) {
+    if (rbuf->super.current_size == rbuf->super.datagram_size) {
         gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(rbuf->super.src,
                                                      rbuf->super.src_len,
                                                      rbuf->super.dst,

sys/net/gnrc/network_layer/sixlowpan/frag/vrb/Makefile

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

sys/net/gnrc/network_layer/sixlowpan/frag/vrb/gnrc_sixlowpan_frag_vrb.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @author  Martine Lenders <m.lenders@fu-berlin.de>
+ */
+
+#include "net/ieee802154.h"
+#include "xtimer.h"
+
+#include "net/gnrc/sixlowpan/frag/vrb.h"
+
+#define ENABLE_DEBUG    (0)
+#include "debug.h"
+
+static gnrc_sixlowpan_frag_vrb_t _vrb[GNRC_SIXLOWPAN_FRAG_VRB_SIZE];
+static char l2addr_str[3 * IEEE802154_LONG_ADDRESS_LEN];
+
+#if !defined(MODULE_GNRC_SIXLOWPAN_FRAG) && defined(TEST_SUITES)
+/* mock for e.g. testing */
+uint16_t tag = 0;
+
+uint16_t gnrc_sixlowpan_frag_next_tag(void)
+{
+    return tag++;
+}
+#endif  /* !defined(MODULE_GNRC_SIXLOWPAN_FRAG) && defined(TEST_SUITES) */
+
+gnrc_sixlowpan_frag_vrb_t *gnrc_sixlowpan_frag_vrb_add(
+        const gnrc_sixlowpan_rbuf_base_t *base,
+        gnrc_netif_t *out_netif, const uint8_t *out_dst, size_t out_dst_len)
+{
+    gnrc_sixlowpan_frag_vrb_t *vrbe = NULL;
+
+    assert(base != NULL);
+    assert(out_netif != NULL);
+    assert(out_dst != NULL);
+    assert(out_dst_len > 0);
+    for (unsigned i = 0; i < GNRC_SIXLOWPAN_FRAG_VRB_SIZE; i++) {
+        gnrc_sixlowpan_frag_vrb_t *ptr = &_vrb[i];
+
+        if (gnrc_sixlowpan_frag_vrb_entry_empty(ptr) ||
+            (memcmp(&ptr->super, base, sizeof(ptr->super)) == 0)) {
+            vrbe = ptr;
+            if (gnrc_sixlowpan_frag_vrb_entry_empty(vrbe)) {
+                vrbe->super = *base;
+                vrbe->out_netif = out_netif;
+                memcpy(vrbe->out_dst, out_dst, out_dst_len);
+                vrbe->out_tag = gnrc_sixlowpan_frag_next_tag();
+                vrbe->out_dst_len = out_dst_len;
+                DEBUG("6lo vrb: creating entry (%s, ",
+                      gnrc_netif_addr_to_str(vrbe->super.src,
+                                             vrbe->super.src_len,
+                                             l2addr_str));
+                DEBUG("%s, %u, %u) => ",
+                      gnrc_netif_addr_to_str(vrbe->super.dst,
+                                             vrbe->super.dst_len,
+                                             l2addr_str),
+                      (unsigned)vrbe->super.datagram_size, vrbe->super.tag);
+                DEBUG("(%s, %u)\n",
+                      gnrc_netif_addr_to_str(vrbe->out_dst,
+                                             vrbe->out_dst_len,
+                                             l2addr_str), vrbe->out_tag);
+            }
+            break;
+        }
+    }
+    return vrbe;
+}
+
+gnrc_sixlowpan_frag_vrb_t *gnrc_sixlowpan_frag_vrb_get(
+        const uint8_t *src, size_t src_len,
+        const uint8_t *dst, size_t dst_len,
+        size_t datagram_size, unsigned src_tag)
+{
+    DEBUG("6lo vrb: trying to get entry for (%s, ",
+          gnrc_netif_addr_to_str(src, src_len, l2addr_str));
+    DEBUG("%s, %u, %u)\n",
+          gnrc_netif_addr_to_str(dst, dst_len, l2addr_str),
+          (unsigned)datagram_size, src_tag);
+    for (unsigned i = 0; i < GNRC_SIXLOWPAN_FRAG_VRB_SIZE; i++) {
+        gnrc_sixlowpan_frag_vrb_t *vrbe = &_vrb[i];
+
+        if ((vrbe->super.datagram_size == datagram_size) &&
+            (vrbe->super.tag == src_tag) &&
+            (vrbe->super.src_len == src_len) &&
+            (vrbe->super.dst_len == dst_len) &&
+            (memcmp(vrbe->super.src, src, src_len) == 0) &&
+            (memcmp(vrbe->super.dst, dst, dst_len) == 0)) {
+            DEBUG("6lo vrb: got VRB to (%s, %u)\n",
+                  gnrc_netif_addr_to_str(vrbe->out_dst,
+                                         vrbe->out_dst_len,
+                                         l2addr_str), vrbe->out_tag);
+            return vrbe;
+        }
+    }
+    DEBUG("6lo vrb: no entry found\n");
+    return NULL;
+}
+
+void gnrc_sixlowpan_frag_vrb_gc(void)
+{
+    uint32_t now_usec = xtimer_now_usec();
+
+    for (unsigned i = 0; i < GNRC_SIXLOWPAN_FRAG_VRB_SIZE; i++) {
+        if (!gnrc_sixlowpan_frag_vrb_entry_empty(&_vrb[i]) &&
+            (now_usec - _vrb[i].super.arrival) > GNRC_SIXLOWPAN_FRAG_VRB_TIMEOUT_US) {
+            DEBUG("6lo vrb: entry (%s, ",
+                  gnrc_netif_addr_to_str(_vrb[i].super.src,
+                                         _vrb[i].super.src_len,
+                                         l2addr_str));
+            DEBUG("%s, %u, %u) timed out\n",
+                  gnrc_netif_addr_to_str(_vrb[i].super.dst,
+                                         _vrb[i].super.dst_len,
+                                         l2addr_str),
+                  (unsigned)_vrb[i].super.datagram_size, _vrb[i].super.tag);
+            gnrc_sixlowpan_frag_vrb_rm(&_vrb[i]);
+        }
+    }
+}
+
+#ifdef TEST_SUITES
+void gnrc_sixlowpan_frag_vrb_reset(void)
+{
+    memset(_vrb, 0, sizeof(_vrb));
+}
+#endif
+
+/** @} */