gnrc_sixlowpan_iphc: forward received fragments

RIOT-OS · Dec 1, 2020 · e9d34e2 · e9d34e2
1 parent d9f3c08
commit e9d34e2
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Showing 2 changed files with 20 additions and 5 deletions.
diff --git a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c b/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c
@@ -589,11 +589,24 @@ static int _rbuf_get(const void *src, size_t src_len,
         default:
             reass_type = GNRC_NETTYPE_UNDEF;
     }
-#ifdef MODULE_GNRC_SIXLOWPAN_FRAG_VRB
-    res->pkt = gnrc_pktbuf_add(NULL, NULL, 0, reass_type);
-#else   /* MODULE_GNRC_SIXLOWPAN_FRAG_VRB */
-    res->pkt = gnrc_pktbuf_add(NULL, NULL, size, reass_type);
-#endif  /* MODULE_GNRC_SIXLOWPAN_FRAG_VRB */
+    if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_VRB)) {
+        if (IS_USED(MODULE_GNRC_SIXLOWPAN_IPHC)) {
+            /* only allocate enough space to decompress IPv6 header
+             * for forwarding information */
+            res->pkt = gnrc_pktbuf_add(NULL, NULL, sizeof(ipv6_hdr_t),
+                                       reass_type);
+        }
+        else {
+            /* try fragment forwarding without IPHC. Since `res->pkt == NULL`
+             * is not a valid value for a reassembly buffer entry, we need to
+             * set it to at least a packet snip for now */
+            res->pkt = gnrc_pktbuf_add(NULL, NULL, 0, reass_type);
+        }
+    }
+    else {
+        /* reassemble whole datagram without direct fragment forwarding */
+        res->pkt = gnrc_pktbuf_add(NULL, NULL, size, reass_type);
+    }
     if (res->pkt == NULL) {
         DEBUG("6lo rfrag: can not allocate reassembly buffer space.\n");
         return -1;

diff --git a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c b/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c
@@ -824,6 +824,7 @@ void gnrc_sixlowpan_iphc_recv(gnrc_pktsnip_t *sixlo, void *rbuf_ptr,
                        payload_offset - sizeof(ipv6_hdr_t));
     }
     if ((rbuf == NULL) &&
+        /* (rbuf == NULL) => forwarding is not affected by this */
         (gnrc_pktbuf_realloc_data(ipv6, uncomp_hdr_len + payload_len) != 0)) {
         DEBUG("6lo iphc: no space left to copy payload\n");
         _recv_error_release(sixlo, ipv6, rbuf);
@@ -852,6 +853,7 @@ void gnrc_sixlowpan_iphc_recv(gnrc_pktsnip_t *sixlo, void *rbuf_ptr,
                 }
             }
             if ((ipv6 == NULL) || (res < 0)) {
+                /* TODO fall-back to reassembly in minfwd when ipv6 != NULL */
                 gnrc_sixlowpan_frag_vrb_rm(vrbe);
             }
             gnrc_pktbuf_release(sixlo);