ipv6/nib: bugfix handle SLLAO on 6LR if ARO is not present

RIOT-OS · Apr 4, 2022 · 475e081 · 475e081
1 parent 7bcc673
commit 475e081
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Showing 3 changed files with 30 additions and 22 deletions.
diff --git a/sys/net/gnrc/network_layer/ipv6/nib/_nib-6lr.c b/sys/net/gnrc/network_layer/ipv6/nib/_nib-6lr.c
@@ -136,28 +136,26 @@ gnrc_pktsnip_t *_copy_and_handle_aro(gnrc_netif_t *netif,
                                      const ndp_opt_t *sl2ao)
 {
     gnrc_pktsnip_t *reply_aro = NULL;
-
-    if (aro != NULL) {
-        uint8_t status = _handle_aro(netif, ipv6, (icmpv6_hdr_t *)nbr_sol, aro,
-                                     sl2ao, NULL);
-
-        if ((status != _ADDR_REG_STATUS_TENTATIVE) &&
-            (status != _ADDR_REG_STATUS_IGNORE)) {
-            reply_aro = gnrc_sixlowpan_nd_opt_ar_build(status,
-                                                       byteorder_ntohs(aro->ltime),
-                                                       (eui64_t *)&aro->eui64,
-                                                       NULL);
-            if (reply_aro == NULL) {
-                DEBUG("nib: No space left in packet buffer. Not replying NS");
-            }
+    assert(aro);
+    uint8_t status = _handle_aro(netif, ipv6, (icmpv6_hdr_t *)nbr_sol, aro,
+                                    sl2ao, NULL);
+
+    if ((status != _ADDR_REG_STATUS_TENTATIVE) &&
+        (status != _ADDR_REG_STATUS_IGNORE)) {
+        reply_aro = gnrc_sixlowpan_nd_opt_ar_build(status,
+                                                    byteorder_ntohs(aro->ltime),
+                                                    (eui64_t *)&aro->eui64,
+                                                    NULL);
+        if (reply_aro == NULL) {
+            DEBUG("nib: No space left in packet buffer. Not replying NS");
         }
+    }
 #if IS_ACTIVE(CONFIG_GNRC_IPV6_NIB_MULTIHOP_DAD)
-        else if (status != _ADDR_REG_STATUS_IGNORE) {
-            DEBUG("nib: Address was marked TENTATIVE => not replying NS, "
-                  "waiting for DAC\n");
-        }
-#endif  /* CONFIG_GNRC_IPV6_NIB_MULTIHOP_DAD */
+    else if (status != _ADDR_REG_STATUS_IGNORE) {
+        DEBUG("nib: Address was marked TENTATIVE => not replying NS, "
+                "waiting for DAC\n");
     }
+#endif  /* CONFIG_GNRC_IPV6_NIB_MULTIHOP_DAD */
     return reply_aro;
 }
 #else  /* CONFIG_GNRC_IPV6_NIB_6LR */

diff --git a/sys/net/gnrc/network_layer/ipv6/nib/_nib-6lr.h b/sys/net/gnrc/network_layer/ipv6/nib/_nib-6lr.h
@@ -106,7 +106,7 @@ uint8_t _reg_addr_upstream(gnrc_netif_t *netif, const ipv6_hdr_t *ipv6,
  * @param[in] nbr_sol   The neighbor solicitation carrying the original ARO
  *                      (handed over as @ref icmpv6_hdr_t, since it is just
  *                      handed to @ref _handle_aro()).
- * @param[in] aro       The original ARO
+ * @param[in] aro       The original ARO, must not be NULL
  * @param[in] sl2ao     SL2AO associated with the ARO.
  *
  * @return  registration status of the address (including

diff --git a/sys/net/gnrc/network_layer/ipv6/nib/nib.c b/sys/net/gnrc/network_layer/ipv6/nib/nib.c
@@ -1027,7 +1027,7 @@ static void _handle_nbr_sol(gnrc_netif_t *netif, const ipv6_hdr_t *ipv6,
                     if (gnrc_netif_is_6lr(netif)) {
                         DEBUG("nib: Storing SL2AO for later handling\n");
                         sl2ao = opt;
-                        break;
+                        break; /* SL2AO is handled below together with an ARO */
                     }
 #endif  /* CONFIG_GNRC_IPV6_NIB_6LR */
                     _handle_sl2ao(netif, ipv6, (const icmpv6_hdr_t *)nbr_sol,
@@ -1045,7 +1045,17 @@ static void _handle_nbr_sol(gnrc_netif_t *netif, const ipv6_hdr_t *ipv6,
                     break;
             }
         }
-        reply_aro = _copy_and_handle_aro(netif, ipv6, nbr_sol, aro, sl2ao);
+        if (aro && sl2ao) {
+        /* If no SLLAO is included, then any included ARO is ignored. */
+            if (!(reply_aro = _copy_and_handle_aro(netif, ipv6, nbr_sol, aro, sl2ao))) {
+            /* If the Length field is not two, or if the Status field is not zero,
+               then the NS is silently ignored.*/
+                return;
+            }
+        }
+        else if (sl2ao) {
+            _handle_sl2ao(netif, ipv6, (const icmpv6_hdr_t *)nbr_sol, sl2ao);
+        }
         /* check if target address is anycast */
         if (netif->ipv6.addrs_flags[tgt_idx] & GNRC_NETIF_IPV6_ADDRS_FLAGS_ANYCAST) {
             _send_delayed_nbr_adv(netif, &nbr_sol->tgt, ipv6, reply_aro);