gnrc_sixlowpan_frag: Expose functions to finish datagram

This will be used in the IPHC refactoring to control the reassembly
buffer as a context.

I also adapted the name of `gnrc_sixlowpan_frag_gc_rbuf()` to be in
line with the rest of the newer functions.

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

@@ -31,6 +31,7 @@
 #include "byteorder.h"
 #include "kernel_types.h"
 #include "net/gnrc/pkt.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/ieee802154.h"
 #include "net/sixlowpan.h"
 
@@ -131,7 +132,39 @@ void gnrc_sixlowpan_frag_recv(gnrc_pktsnip_t *pkt, void *ctx, unsigned page);
 /**
  * @brief   Garbage collect reassembly buffer.
  */
-void gnrc_sixlowpan_frag_gc_rbuf(void);
+void gnrc_sixlowpan_frag_rbuf_gc(void);
+
+#if defined(MODULE_GNRC_SIXLOWPAN_FRAG) || defined(DOXYGEN)
+/**
+ * @brief   Removes an entry from the reassembly buffer
+ *
+ * @pre `rbuf != NULL`
+ *
+ * @param[in] rbuf  A reassembly buffer entry. Must not be NULL.
+ */
+void gnrc_sixlowpan_frag_rbuf_remove(gnrc_sixlowpan_rbuf_t *rbuf);
+
+/**
+ * @brief   Checks if a reassembly buffer entry is complete and dispatches it
+ *          to the next layer if that is the case
+ *
+ * @pre `rbuf != NULL`
+ * @pre `netif != NULL`
+ *
+ * @param[in] rbuf  A reassembly buffer entry. Must not be NULL.
+ * @param[in] netif Original @ref gnrc_netif_hdr_t of the last received frame.
+ *                  Used to construct the @ref gnrc_netif_hdr_t of the completed
+ *                  datagram. Must not be NULL.
+ */
+void gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(gnrc_sixlowpan_rbuf_t *rbuf,
+                                                     gnrc_netif_hdr_t *netif);
+#else
+/* NOPs to be used with gnrc_sixlowpan_iphc if gnrc_sixlowpan_frag is not
+ * compiled in */
+#define gnrc_sixlowpan_frag_rbuf_remove(rbuf)       (void)(rbuf)
+#define gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(rbuf, netif) \
+    (void)(rbuf); (void)(netif)
+#endif
 
 #ifdef __cplusplus
 }

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

@@ -320,9 +320,48 @@ void gnrc_sixlowpan_frag_recv(gnrc_pktsnip_t *pkt, void *ctx, unsigned page)
     gnrc_pktbuf_release(pkt);
 }
 
-void gnrc_sixlowpan_frag_gc_rbuf(void)
+void gnrc_sixlowpan_frag_rbuf_gc(void)
 {
     rbuf_gc();
 }
 
+void gnrc_sixlowpan_frag_rbuf_remove(gnrc_sixlowpan_rbuf_t *rbuf)
+{
+    assert(rbuf != NULL);
+    rbuf_rm((rbuf_t *)rbuf);
+}
+
+void gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(gnrc_sixlowpan_rbuf_t *rbuf,
+                                                     gnrc_netif_hdr_t *netif_hdr)
+{
+    assert(rbuf);
+    assert(netif_hdr);
+    if (rbuf->current_size == rbuf->pkt->size) {
+        gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(rbuf->src,
+                                                     rbuf->src_len,
+                                                     rbuf->dst,
+                                                     rbuf->dst_len);
+
+        if (netif == NULL) {
+            DEBUG("6lo rbuf: error allocating netif header\n");
+            gnrc_pktbuf_release(rbuf->pkt);
+            gnrc_sixlowpan_frag_rbuf_remove(rbuf);
+            return;
+        }
+
+        /* copy the transmit information of the latest fragment into the newly
+         * created header to have some link_layer information. The link_layer
+         * info of the previous fragments is discarded.
+         */
+        gnrc_netif_hdr_t *new_netif_hdr = netif->data;
+        new_netif_hdr->if_pid = netif_hdr->if_pid;
+        new_netif_hdr->flags = netif_hdr->flags;
+        new_netif_hdr->lqi = netif_hdr->lqi;
+        new_netif_hdr->rssi = netif_hdr->rssi;
+        LL_APPEND(rbuf->pkt, netif);
+        gnrc_sixlowpan_dispatch_recv(rbuf->pkt, NULL, 0);
+        gnrc_sixlowpan_frag_rbuf_remove(rbuf);
+    }
+}
+
 /** @} */

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

@@ -58,8 +58,6 @@ static msg_t _gc_timer_msg = { .type = GNRC_SIXLOWPAN_MSG_FRAG_GC_RBUF };
 static inline bool _rbuf_int_overlap_partially(rbuf_int_t *i, uint16_t start, uint16_t end);
 /* gets a free entry from interval buffer */
 static rbuf_int_t *_rbuf_int_get_free(void);
-/* remove entry from reassembly buffer */
-static void _rbuf_rem(rbuf_t *entry);
 /* update interval buffer of entry */
 static bool _rbuf_update_ints(rbuf_t *entry, uint16_t offset, size_t frag_size);
 /* gets an entry identified by its tupel */
@@ -108,7 +106,7 @@ void rbuf_add(gnrc_netif_hdr_t *netif_hdr, gnrc_pktsnip_t *pkt,
             if (iphc_len == 0) {
                 DEBUG("6lo rfrag: could not decode IPHC dispatch\n");
                 gnrc_pktbuf_release(entry->super.pkt);
-                _rbuf_rem(entry);
+                rbuf_rm(entry);
                 return;
             }
             data += iphc_len;       /* take remaining data as data */
@@ -127,7 +125,7 @@ void rbuf_add(gnrc_netif_hdr_t *netif_hdr, gnrc_pktsnip_t *pkt,
     if ((offset + frag_size) > entry->super.pkt->size) {
         DEBUG("6lo rfrag: fragment too big for resulting datagram, discarding datagram\n");
         gnrc_pktbuf_release(entry->super.pkt);
-        _rbuf_rem(entry);
+        rbuf_rm(entry);
         return;
     }
 
@@ -138,7 +136,7 @@ void rbuf_add(gnrc_netif_hdr_t *netif_hdr, gnrc_pktsnip_t *pkt,
         if (_rbuf_int_overlap_partially(ptr, offset, offset + frag_size - 1)) {
             DEBUG("6lo rfrag: overlapping intervals, discarding datagram\n");
             gnrc_pktbuf_release(entry->super.pkt);
-            _rbuf_rem(entry);
+            rbuf_rm(entry);
 
             /* "A fresh reassembly may be commenced with the most recently
              * received link fragment"
@@ -158,32 +156,7 @@ void rbuf_add(gnrc_netif_hdr_t *netif_hdr, gnrc_pktsnip_t *pkt,
                frag_size - data_offset);
     }
 
-    if (entry->super.current_size == entry->super.pkt->size) {
+    gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(&entry->super, netif_hdr);
-        gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(entry->super.src,
-                                                     entry->super.src_len,
-                                                     entry->super.dst,
-                                                     entry->super.dst_len);
-
-        if (netif == NULL) {
-            DEBUG("6lo rbuf: error allocating netif header\n");
-            gnrc_pktbuf_release(entry->super.pkt);
-            _rbuf_rem(entry);
-            return;
-        }
-
-        /* copy the transmit information of the latest fragment into the newly
-         * created header to have some link_layer information. The link_layer
-         * info of the previous fragments is discarded.
-         */
-        gnrc_netif_hdr_t *new_netif_hdr = netif->data;
-        new_netif_hdr->if_pid = netif_hdr->if_pid;
-        new_netif_hdr->flags = netif_hdr->flags;
-        new_netif_hdr->lqi = netif_hdr->lqi;
-        new_netif_hdr->rssi = netif_hdr->rssi;
-        LL_APPEND(entry->super.pkt, netif);
-        gnrc_sixlowpan_dispatch_recv(entry->super.pkt, NULL, 0);
-        _rbuf_rem(entry);
-    }
 }
 
 static inline bool _rbuf_int_overlap_partially(rbuf_int_t *i, uint16_t start, uint16_t end)
@@ -204,7 +177,7 @@ static rbuf_int_t *_rbuf_int_get_free(void)
     return NULL;
 }
 
-static void _rbuf_rem(rbuf_t *entry)
+void rbuf_rm(rbuf_t *entry)
 {
     while (entry->ints != NULL) {
         rbuf_int_t *next = entry->ints->next;
@@ -267,7 +240,7 @@ void rbuf_gc(void)
                   (unsigned)rbuf[i].super.pkt->size, rbuf[i].super.tag);
 
             gnrc_pktbuf_release(rbuf[i].super.pkt);
-            _rbuf_rem(&(rbuf[i]));
+            rbuf_rm(&(rbuf[i]));
         }
     }
 }
@@ -324,7 +297,7 @@ static rbuf_t *_rbuf_get(const void *src, size_t src_len,
         assert(oldest->super.pkt != NULL);
         DEBUG("6lo rfrag: reassembly buffer full, remove oldest entry\n");
         gnrc_pktbuf_release(oldest->super.pkt);
-        _rbuf_rem(oldest);
+        rbuf_rm(oldest);
         res = oldest;
     }
 

sys/net/gnrc/network_layer/sixlowpan/frag/rbuf.h

@@ -89,6 +89,8 @@ void rbuf_add(gnrc_netif_hdr_t *netif_hdr, gnrc_pktsnip_t *frag,
  */
 void rbuf_gc(void);
 
+void rbuf_rm(rbuf_t *rbuf);
+
 #ifdef __cplusplus
 }
 #endif

sys/net/gnrc/network_layer/sixlowpan/gnrc_sixlowpan.c

@@ -377,7 +377,7 @@ static void *_event_loop(void *args)
                 break;
             case GNRC_SIXLOWPAN_MSG_FRAG_GC_RBUF:
                 DEBUG("6lo: garbage collect reassembly buffer event received\n");
-                gnrc_sixlowpan_frag_gc_rbuf();
+                gnrc_sixlowpan_frag_rbuf_gc();
                 break;
 #endif