gnrc_ipv6_nib: provide internal implementation for off-link entries

sys/include/net/gnrc/ipv6/nib/conf.h

@@ -184,6 +184,16 @@ extern "C" {
 #define GNRC_IPV6_NIB_NUMOF                 (4)
 #endif
 
+/**
+ * @brief   Number of off-link entries in NIB
+ *
+ * @attention   This number is equal to the maximum number of forwarding table
+ *              and prefix list entries in NIB
+ */
+#ifndef GNRC_IPV6_NIB_OFFL_NUMOF
+#define GNRC_IPV6_NIB_OFFL_NUMOF            (8)
+#endif
+
 #ifdef __cplusplus
 }
 #endif

sys/net/gnrc/network_layer/ipv6/nib/_nib-internal.c

@@ -33,6 +33,7 @@ static _nib_dr_entry_t *_prime_def_router = NULL;
 static clist_node_t _next_removable = { NULL };
 
 static _nib_onl_entry_t _nodes[GNRC_IPV6_NIB_NUMOF];
+static _nib_offl_entry_t _dsts[GNRC_IPV6_NIB_OFFL_NUMOF];
 static _nib_dr_entry_t _def_routers[GNRC_IPV6_NIB_DEFAULT_ROUTER_NUMOF];
 static _nib_iface_t _nis[GNRC_NETIF_NUMOF];
 
@@ -53,33 +54,41 @@ void _nib_init(void)
     _next_removable.next = NULL;
     memset(_nodes, 0, sizeof(_nodes));
     memset(_def_routers, 0, sizeof(_def_routers));
+    memset(_dsts, 0, sizeof(_dsts));
     memset(_nis, 0, sizeof(_nis));
 #endif
     /* TODO: load ABR information from persistent memory */
 }
 
+static inline bool _addr_equals(const ipv6_addr_t *addr,
+                                const _nib_onl_entry_t *node)
+{
+    return (addr == NULL) || ipv6_addr_is_unspecified(&node->ipv6) ||
+           (ipv6_addr_equal(addr, &node->ipv6));
+}
+
 _nib_onl_entry_t *_nib_onl_alloc(const ipv6_addr_t *addr, unsigned iface)
 {
     _nib_onl_entry_t *node = NULL;
 
-    assert(addr != NULL);
     DEBUG("nib: Allocating on-link node entry (addr = %s, iface = %u)\n",
-          ipv6_addr_to_str(addr_str, addr, sizeof(addr_str)), iface);
+          (addr == NULL) ? "NULL" : ipv6_addr_to_str(addr_str, addr,
+                                                     sizeof(addr_str)), iface);
     for (unsigned i = 0; i < GNRC_IPV6_NIB_NUMOF; i++) {
         _nib_onl_entry_t *tmp = &_nodes[i];
 
-        if ((_nib_onl_get_if(tmp) == iface) &&
+        if ((_nib_onl_get_if(tmp) == iface) && _addr_equals(addr, tmp)) {
-            (ipv6_addr_equal(addr, &tmp->ipv6))) {
             /* exact match */
             DEBUG("  %p is an exact match\n", (void *)tmp);
-            return tmp;
+            node = tmp;
+            break;
         }
         if ((node == NULL) && (tmp->mode == _EMPTY)) {
+            DEBUG("  using %p\n", (void *)node);
             node = tmp;
         }
     }
     if (node != NULL) {
-        DEBUG("  using %p\n", (void *)node);
         _override_node(addr, iface, node);
     }
 #if ENABLE_DEBUG
@@ -141,6 +150,7 @@ static inline _nib_onl_entry_t *_cache_out_onl_entry(const ipv6_addr_t *addr,
 _nib_onl_entry_t *_nib_nc_add(const ipv6_addr_t *addr, unsigned iface,
                               uint16_t cstate)
 {
+    assert(addr != NULL);
     cstate &= GNRC_IPV6_NIB_NC_INFO_NUD_STATE_MASK;
     assert(cstate != GNRC_IPV6_NIB_NC_INFO_NUD_STATE_DELAY);
     assert(cstate != GNRC_IPV6_NIB_NC_INFO_NUD_STATE_PROBE);
@@ -341,6 +351,95 @@ _nib_dr_entry_t *_nib_drl_get_dr(void)
     return _prime_def_router;
 }
 
+_nib_offl_entry_t *_nib_offl_alloc(const ipv6_addr_t *next_hop, unsigned iface,
+                                   const ipv6_addr_t *pfx, unsigned pfx_len)
+{
+    _nib_offl_entry_t *dst = NULL;
+
+    assert((pfx != NULL) && (!ipv6_addr_is_unspecified(pfx)) &&
+           (pfx_len > 0) && (pfx_len <= 128));
+    DEBUG("nib: Allocating off-link-entry entry "
+          "(next_hop = %s, iface = %u, ",
+          (next_hop == NULL) ? "NULL" : ipv6_addr_to_str(addr_str, next_hop,
+                                                         sizeof(addr_str)),
+          iface);
+    DEBUG("pfx = %s/%u)\n", ipv6_addr_to_str(addr_str, pfx,
+                                             sizeof(addr_str)), pfx_len);
+    for (unsigned i = 0; i < GNRC_IPV6_NIB_OFFL_NUMOF; i++) {
+        _nib_offl_entry_t *tmp = &_dsts[i];
+        _nib_onl_entry_t *tmp_node = tmp->next_hop;
+
+        if ((tmp->pfx_len == pfx_len) &&                /* prefix length matches and */
+            (tmp_node != NULL) &&                       /* there is a next hop that */
+            (_nib_onl_get_if(tmp_node) == iface) &&     /* has a matching interface and */
+            _addr_equals(next_hop, tmp_node) &&         /* equal address to next_hop, also */
+            (ipv6_addr_match_prefix(&tmp->pfx, pfx) >= pfx_len)) {  /* the prefix matches */
+            /* exact match (or next hop address was previously unset) */
+            DEBUG("  %p is an exact match\n", (void *)tmp);
+            if (next_hop != NULL) {
+                memcpy(&tmp_node->ipv6, next_hop, sizeof(tmp_node->ipv6));
+            }
+            tmp->next_hop->mode |= _DST;
+            return tmp;
+        }
+        if ((dst == NULL) && (tmp_node == NULL)) {
+            dst = tmp;
+        }
+    }
+    if (dst != NULL) {
+        DEBUG("  using %p\n", (void *)dst);
+        dst->next_hop = _nib_onl_alloc(next_hop, iface);
+
+        if (dst->next_hop == NULL) {
+            memset(dst, 0, sizeof(_nib_offl_entry_t));
+            return NULL;
+        }
+        _override_node(next_hop, iface, dst->next_hop);
+        dst->next_hop->mode |= _DST;
+        ipv6_addr_init_prefix(&dst->pfx, pfx, pfx_len);
+        dst->pfx_len = pfx_len;
+    }
+    return dst;
+}
+
+static inline bool _in_dsts(const _nib_offl_entry_t *dst)
+{
+    return (dst < (_dsts + GNRC_IPV6_NIB_OFFL_NUMOF));
+}
+
+void _nib_offl_clear(_nib_offl_entry_t *dst)
+{
+    if (dst->next_hop != NULL) {
+        _nib_offl_entry_t *ptr;
+        for (ptr = _dsts; _in_dsts(ptr); ptr++) {
+            /* there is another dst pointing to next-hop => only remove dst */
+            if ((dst != ptr) && (dst->next_hop == ptr->next_hop)) {
+                break;
+            }
+        }
+        /* we iterated and found no further dst pointing to next-hop */
+        if (!_in_dsts(ptr)) {
+            dst->next_hop->mode &= ~(_DST);
+            _nib_onl_clear(dst->next_hop);
+        }
+        memset(dst, 0, sizeof(_nib_offl_entry_t));
+    }
+}
+
+_nib_offl_entry_t *_nib_offl_iter(const _nib_offl_entry_t *last)
+{
+    for (const _nib_offl_entry_t *dst = (last) ? (last + 1) : _dsts;
+         _in_dsts(dst);
+         dst++) {
+        if (dst->mode != _EMPTY) {
+            /* const modifier provided to assure internal consistency.
+             * Can now be discarded. */
+            return (_nib_offl_entry_t *)dst;
+        }
+    }
+    return NULL;
+}
+
 _nib_iface_t *_nib_iface_get(unsigned iface)
 {
     _nib_iface_t *ni = NULL;
@@ -367,7 +466,9 @@ static void _override_node(const ipv6_addr_t *addr, unsigned iface,
                            _nib_onl_entry_t *node)
 {
     _nib_onl_clear(node);
-    memcpy(&node->ipv6, addr, sizeof(node->ipv6));
+    if (addr != NULL) {
+        memcpy(&node->ipv6, addr, sizeof(node->ipv6));
+    }
     _nib_onl_set_if(node, iface);
 }
 

sys/net/gnrc/network_layer/ipv6/nib/_nib-internal.h

@@ -19,6 +19,7 @@
 #ifndef PRIV_NIB_INTERNAL_H
 #define PRIV_NIB_INTERNAL_H
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdint.h>
 
@@ -48,6 +49,8 @@ extern "C" {
 #define _DRL    (0x08)      /**< default router list */
 #define _FT     (0x10)      /**< forwarding table */
 #define _DAD    (0x20)      /**< 6LoWPAN duplicate address detection table */
+#define _DST    (0x40)      /**< there is @ref _nib_offl_entry_t pointing
+                                 to this @ref _nib_onl_entry_t */
 /** @} */
 
 /**
@@ -148,6 +151,8 @@ typedef struct {
     ipv6_addr_t pfx;            /**< prefix to the destination */
     unsigned pfx_len;           /**< prefix-length in bits of
                                  *   _nib_onl_entry_t::pfx */
+    uint8_t mode;               /**< [mode](@ref net_gnrc_ipv6_nib_mode) of the
+                                 *   off-link entry */
 } _nib_offl_entry_t;
 
 /**
@@ -232,10 +237,8 @@ static inline void _nib_onl_set_if(_nib_onl_entry_t *node, unsigned iface)
 /**
  * @brief   Creates or gets an existing on-link entry by address
  *
- * @pre     `(addr != NULL)`.
+ * @param[in] addr  An IPv6 address. May be NULL (to be pointed to by a prefix
- *
+ *                  list entry). *May also be a global address!*
- * @param[in] addr  An IPv6 address. May not be NULL.
- *                  *May also be a global address!*
  * @param[in] iface The interface to the node.
  *
  * @return  A new or existing on-link entry with _nib_onl_entry_t::ipv6 set to
@@ -286,7 +289,6 @@ _nib_onl_entry_t *_nib_onl_get(const ipv6_addr_t *addr, unsigned iface);
 /**
  * @brief   Creates or gets an existing node from the neighbor cache by address
  *
- * @pre     `(addr != NULL)`
  * @pre     `((cstate & GNRC_IPV6_NIB_NC_INFO_NUD_STATE_MASK) !=
  *             GNRC_IPV6_NIB_NC_INFO_NUD_STATE_DELAY)`
  * @pre     `((cstate & GNRC_IPV6_NIB_NC_INFO_NUD_STATE_MASK) !=
@@ -294,7 +296,8 @@ _nib_onl_entry_t *_nib_onl_get(const ipv6_addr_t *addr, unsigned iface);
  * @pre     `((cstate & GNRC_IPV6_NIB_NC_INFO_NUD_STATE_MASK) !=
  *             GNRC_IPV6_NIB_NC_INFO_NUD_STATE_REACHABLE)`
  *
- * @param[in] addr      The address of a node. May not be NULL.
+ * @param[in] addr      The address of a node. May be NULL for prefix list
+ *                      entries.
  * @param[in] iface     The interface to the node.
  * @param[in] cstate    Creation state. State of the entry *if* the entry is
  *                      newly created.
@@ -333,6 +336,7 @@ void _nib_nc_set_reachable(_nib_onl_entry_t *node);
  */
 static inline _nib_onl_entry_t *_nib_dad_add(const ipv6_addr_t *addr)
 {
+    assert(addr != NULL);
     _nib_onl_entry_t *node = _nib_onl_alloc(addr, 0);
 
     if (node != NULL) {
@@ -412,11 +416,10 @@ _nib_dr_entry_t *_nib_drl_get_dr(void);
 /**
  * @brief   Creates or gets an existing off-link entry by next hop and prefix
  *
- * @pre `(next_hop != NULL)`
  * @pre `(pfx != NULL) && (pfx != "::") && (pfx_len != 0) && (pfx_len <= 128)`
  *
- * @param[in] next_hop  An IPv6 address to next hop. May not be NULL.
+ * @param[in] next_hop  An IPv6 address to next hop. May be NULL (for prefix
- *                      *May also be a global address!*
+ *                      list). *May also be a global address!*
  * @param[in] iface     The interface to @p next_hop.
  * @param[in] pfx       The IPv6 prefix or address of the destination.
  *                      May not be NULL or unspecified address. Use
@@ -427,15 +430,15 @@ _nib_dr_entry_t *_nib_drl_get_dr(void);
  *          @p pfx.
  * @return  NULL, if no space is left.
  */
-_nib_offl_entry_t *_nib_dst_alloc(const ipv6_addr_t *next_hop, unsigned iface,
+_nib_offl_entry_t *_nib_offl_alloc(const ipv6_addr_t *next_hop, unsigned iface,
-                                  const ipv6_addr_t *pfx, unsigned pfx_len);
+                                   const ipv6_addr_t *pfx, unsigned pfx_len);
 
 /**
  * @brief   Clears out a NIB entry (off-link version)
  *
  * @param[in,out] dst  An entry.
  */
-void _nib_dst_clear(_nib_offl_entry_t *dst);
+void _nib_offl_clear(_nib_offl_entry_t *dst);
 
 /**
  * @brief   Iterates over off-link entries
@@ -444,16 +447,15 @@ void _nib_dst_clear(_nib_offl_entry_t *dst);
  *
  * @return  entry after @p last.
  */
-_nib_offl_entry_t *_nib_dst_iter(const _nib_offl_entry_t *last);
+_nib_offl_entry_t *_nib_offl_iter(const _nib_offl_entry_t *last);
 
 /**
  * @brief   Helper function for view-level add-functions below
  *
- * @pre     `(next_hop != NULL)`
  * @pre     `(pfx != NULL) && (pfx != "::") && (pfx_len != 0) && (pfx_len <= 128)`
  *
- * @param[in] next_hop  Next hop to the destination. May not be NULL.
+ * @param[in] next_hop  An IPv6 address to next hop. May be NULL (for prefix
- *                      *May also be a global address!*
+ *                      list). *May also be a global address!*
  * @param[in] iface     The interface to the destination.
  * @param[in] pfx       The IPv6 prefix or address of the destination.
  *                      May not be NULL or unspecified address. Use
@@ -461,19 +463,19 @@ _nib_offl_entry_t *_nib_dst_iter(const _nib_offl_entry_t *last);
  * @param[in] pfx_len   The length in bits of @p pfx in bits.
  * @param[in] mode      [NIB-mode](_nib_onl_entry_t::mode).
  *
- * @return  A new or existing off-link entry with _nib_dr_entry_t::pfx set to
+ * @return  A new or existing off-link entry with _nib_offl_entry_t::pfx set to
  *          @p pfx.
  * @return  NULL, if no space is left.
  */
-static inline _nib_offl_entry_t *_nib_dst_add(const ipv6_addr_t *next_hop,
+static inline _nib_offl_entry_t *_nib_offl_add(const ipv6_addr_t *next_hop,
-                                              unsigned iface,
+                                               unsigned iface,
-                                              const ipv6_addr_t *pfx,
+                                               const ipv6_addr_t *pfx,
-                                              unsigned pfx_len, uint8_t mode)
+                                               unsigned pfx_len, uint8_t mode)
 {
-    _nib_offl_entry_t *nib_offl = _nib_dst_alloc(next_hop, iface, pfx, pfx_len);
+    _nib_offl_entry_t *nib_offl = _nib_offl_alloc(next_hop, iface, pfx, pfx_len);
 
     if (nib_offl != NULL) {
-        nib_offl->next_hop->mode |= (mode);
+        nib_offl->mode |= mode;
     }
     return nib_offl;
 }
@@ -483,17 +485,13 @@ static inline _nib_offl_entry_t *_nib_dst_add(const ipv6_addr_t *next_hop,
  *
  * @param[in,out] nib_offl  An entry.
  */
-static inline void _nib_dst_remove(_nib_offl_entry_t *nib_offl, uint8_t mode)
+static inline void _nib_offl_remove(_nib_offl_entry_t *nib_offl, uint8_t mode)
 {
-    _nib_onl_entry_t *node = nib_offl->next_hop;
+    nib_offl->mode &= ~mode;
-
+    _nib_offl_clear(nib_offl);
-    if (node != NULL) {
-        node->mode &= ~mode;
-    }
-    _nib_dst_clear(nib_offl);
 }
 
-#if defined(GNRC_IPV6_NIB_CONF_DC) || DOXYGEN
+#if GNRC_IPV6_NIB_CONF_DC || DOXYGEN
 /**
  * @brief   Creates or gets an existing destination cache entry by its addresses
  *
@@ -506,16 +504,16 @@ static inline void _nib_dst_remove(_nib_offl_entry_t *nib_offl, uint8_t mode)
  *
  * @note    Only available if @ref GNRC_IPV6_NIB_CONF_DC.
  *
- * @return  A new or existing destination cache entry with
+ * @return  A new or existing off-link entry with _nib_offl_entry_t::pfx set to
- *          _nib_onl_entry_t::ipv6 of _nib_dr_entry_t::next_hop set to
+ *          @p pfx.
- *          @p next_hop.
  * @return  NULL, if no space is left.
  */
 static inline _nib_offl_entry_t *_nib_dc_add(const ipv6_addr_t *next_hop,
                                              unsigned iface,
                                              const ipv6_addr_t *dst)
 {
-    return _nib_dst_add(next_hop, iface, dst, IPV6_ADDR_BIT_LEN, _DC);
+    assert((next_hop != NULL) && (dst != NULL));
+    return _nib_offl_add(next_hop, iface, dst, IPV6_ADDR_BIT_LEN, _DC);
 }
 
 /**
@@ -529,7 +527,7 @@ static inline _nib_offl_entry_t *_nib_dc_add(const ipv6_addr_t *next_hop,
  */
 static inline void _nib_dc_remove(_nib_offl_entry_t *nib_offl)
 {
-    _nib_dst_remove(nib_offl, _DC);
+    _nib_offl_remove(nib_offl, _DC);
 }
 #endif /* GNRC_IPV6_NIB_CONF_DC */
 
@@ -545,7 +543,7 @@ static inline void _nib_dc_remove(_nib_offl_entry_t *nib_offl)
  *                      @ref _nib_drl_add() for default route destinations.
  * @param[in] pfx_len   The length in bits of @p pfx in bits.
  *
- * @return  A new or existing prefix list entry with _nib_dr_entry_t::pfx set to
+ * @return  A new or existing off-link entry with _nib_offl_entry_t::pfx set to
  *          @p pfx.
  * @return  NULL, if no space is left.
  */
@@ -553,7 +551,7 @@ static inline _nib_offl_entry_t *_nib_pl_add(unsigned iface,
                                              const ipv6_addr_t *pfx,
                                              unsigned pfx_len)
 {
-    return _nib_dst_add(NULL, iface, pfx, pfx_len, _PL);
+    return _nib_offl_add(NULL, iface, pfx, pfx_len, _PL);
 }
 
 /**
@@ -565,10 +563,10 @@ static inline _nib_offl_entry_t *_nib_pl_add(unsigned iface,
  */
 static inline void _nib_pl_remove(_nib_offl_entry_t *nib_offl)
 {
-    _nib_dst_remove(nib_offl, _PL);
+    _nib_offl_remove(nib_offl, _PL);
 }
 
-#if defined(GNRC_IPV6_NIB_CONF_ROUTER) || DOXYGEN
+#if GNRC_IPV6_NIB_CONF_ROUTER || DOXYGEN
 /**
  * @brief   Creates or gets an existing forwarding table entry by its prefix
  *
@@ -585,8 +583,8 @@ static inline void _nib_pl_remove(_nib_offl_entry_t *nib_offl)
  *
  * @note    Only available if @ref GNRC_IPV6_NIB_CONF_ROUTER.
  *
- * @return  A new or existing forwarding table entry with _nib_dr_entry_t::pfx
+ * @return  A new or existing off-link entry with _nib_offl_entry_t::pfx set to
- *          set to @p pfx.
+ *          @p pfx.
  * @return  NULL, if no space is left.
  */
 static inline _nib_offl_entry_t *_nib_ft_add(const ipv6_addr_t *next_hop,
@@ -594,7 +592,7 @@ static inline _nib_offl_entry_t *_nib_ft_add(const ipv6_addr_t *next_hop,
                                              const ipv6_addr_t *pfx,
                                              unsigned pfx_len)
 {
-    return _nib_dst_add(next_hop, iface, pfx, pfx_len, _FT);
+    return _nib_offl_add(next_hop, iface, pfx, pfx_len, _FT);
 }
 
 /**
@@ -608,7 +606,7 @@ static inline _nib_offl_entry_t *_nib_ft_add(const ipv6_addr_t *next_hop,
  */
 static inline void _nib_ft_remove(_nib_offl_entry_t *nib_offl)
 {
-    _nib_dst_remove(nib_offl, _FT);
+    _nib_offl_remove(nib_offl, _FT);
 }
 #endif  /* GNRC_IPV6_NIB_CONF_ROUTER */