gnrc_dhcpv6_client_6lbr: initial import of a 6LBR DHCPv6 client

Makefile.dep

@@ -96,6 +96,10 @@ ifneq (,$(filter gnrc_dhcpv6_client,$(USEMODULE)))
   USEMODULE += gnrc_sock_udp
 endif
 
+ifneq (,$(filter gnrc_dhcpv6_client_6lbr,$(USEMODULE)))
+  USEMODULE += gnrc_dhcpv6_client
+endif
+
 ifneq (,$(filter gnrc_uhcpc,$(USEMODULE)))
   USEMODULE += uhcpc
   USEMODULE += gnrc_sock_udp

sys/auto_init/auto_init.c

@@ -639,4 +639,10 @@ void auto_init(void)
     extern void dhcpv6_client_auto_init(void);
     dhcpv6_client_auto_init();
 #endif /* MODULE_AUTO_INIT_DHCPV6_CLIENT */
+
+#ifdef MODULE_GNRC_DHCPV6_CLIENT_6LBR
+    DEBUG("auto_init 6LoWPAN border router DHCPv6 client");
+    extern void gnrc_dhcpv6_client_6lbr_init(void);
+    gnrc_dhcpv6_client_6lbr_init();
+#endif /* MODULE_GNRC_DHCPV6_CLIENT_6LBR */
 }

sys/include/net/gnrc/dhcpv6/client/6lbr.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2020 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_dhcpv6_client_6lbr  DHCPv6 client for 6LoWPAN border routers
+ * @ingroup     net_dhcpv6_client
+ * @brief       DHCPv6 client bootstrapping for 6LoWPAN border routers
+ * @{
+ *
+ * @file
+ * @brief   DHCPv6 client on 6LoWPAN border router definitions
+ *
+ * @author  Martine S. Lenders <m.lenders@fu-berlin.de>
+ */
+#ifndef NET_GNRC_DHCPV6_CLIENT_6LBR_H
+#define NET_GNRC_DHCPV6_CLIENT_6LBR_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Identifier of the upstream interface
+ *
+ * Leave 0 (default) to let the client pick the first non-6LoWPAN interface it
+ * finds
+ */
+#ifndef CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM
+#define CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM     (0)
+#endif
+
+/**
+ * @brief   Use static routes to upstream router
+ *
+ * If set the border router will be configured to have a default route via
+ * `fe80::1`. The link-local address `fe80::2` will be added so that the
+ * upstream router can set a static route for the delegated prefix via that
+ * address. It is recommended to increase at least @ref
+ * CONFIG_GNRC_NETIF_IPV6_ADDRS_NUMOF to that end.
+ */
+#ifdef DOXYGEN
+#define CONFIG_GNRC_DHCPV6_CLIENT_6LBR_STATIC_ROUTE
+#endif
+
+/**
+ * @brief   Initializes the DHCPv6 client for 6LoWPAN border router
+ *
+ * @note    Called by `auto_init` when included
+ */
+void gnrc_dhcpv6_client_6lbr_init(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NET_GNRC_DHCPV6_CLIENT_6LBR_H */
+/** @} */

sys/net/gnrc/Kconfig

@@ -7,6 +7,7 @@
 menu "GNRC Network stack"
     depends on MODULE_GNRC
 
+rsource "application_layer/dhcpv6/Kconfig"
 rsource "link_layer/lorawan/Kconfig"
 rsource "netif/Kconfig"
 rsource "network_layer/ipv6/Kconfig"

sys/net/gnrc/application_layer/dhcpv6/Kconfig

@@ -0,0 +1,26 @@
+menuconfig KCONFIG_MODULE_GNRC_DHCPV6
+    bool "Configure GNRC-part of DHCPv6"
+    depends on MODULE_GNRC_DHCPV6
+    help
+        Configure GNRC-part of DHCPv6 via Kconfig.
+
+if KCONFIG_MODULE_GNRC_DHCPV6
+
+if MODULE_GNRC_DHCPV6_CLIENT_6LBR
+config GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM
+    int "Identifier for the upstream interface of the 6LoWPAN border router"
+    default 0
+    help
+        Leave 0 to let the client pick the first non-6LoWPAN interface it finds
+
+config GNRC_DHCPV6_CLIENT_6LBR_STATIC_ROUTE
+    bool "Use static routes to upstream interface"
+    help
+        If set to 1 the border router will be configured to have a default
+        route via `fe80::1`. The link-local address `fe80::2` will be added so
+        that the upstream router can set a static route for the delegated
+        prefix via that address. It is recommended to increase at least @ref
+        CONFIG_GNRC_NETIF_IPV6_ADDRS_NUMOF to that end.
+endif # MODULE_GNRC_DHCPV6_CLIENT_6LBR
+
+endif # KCONFIG_MODULE_GNRC_DHCPV6

sys/net/gnrc/application_layer/dhcpv6/client_6lbr.c

@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2018-20 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 S. Lenders <m.lenders@fu-berlin.de>
+ */
+
+#include <assert.h>
+
+#include "event.h"
+#include "log.h"
+#include "net/dhcpv6/client.h"
+#include "net/ipv6/addr.h"
+#include "net/gnrc.h"
+#include "net/gnrc/ipv6/nib/ft.h"
+#include "net/gnrc/netif/internal.h"
+
+#include "net/gnrc/dhcpv6/client/6lbr.h"
+
+#if IS_USED(MODULE_AUTO_INIT_DHCPV6_CLIENT)
+#error "Module `gnrc_dhcpv6_client_6lbr` is mutually exclusive to \
+`auto_init_dhcpv6_client`"
+#endif
+
+static char _stack[DHCPV6_CLIENT_STACK_SIZE];
+
+/**
+ * @brief   Find upstream network interface
+ *
+ * Either the one network interface configured at compile-time with @ref
+ * CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM is picked or the first network
+ * interface that is not a 6LoWPAN interfaces if
+ * `CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM` is 0.
+ *
+ * @return  The upstream network interface.
+ */
+static gnrc_netif_t *_find_upstream_netif(void)
+{
+    gnrc_netif_t *netif = NULL;
+
+    if (CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM) {
+        return gnrc_netif_get_by_pid(CONFIG_GNRC_DHCPV6_CLIENT_6LBR_UPSTREAM);
+    }
+    while ((netif = gnrc_netif_iter(netif))) {
+        if (!gnrc_netif_is_6lo(netif)) {
+            LOG_WARNING("DHCPv6: Selecting interface %d as upstream\n",
+                        netif->pid);
+            return netif;
+        }
+    }
+    return NULL;
+}
+
+/**
+ * @brief   Configure upstream netif to be in line with configuration script
+ *
+ * Set route and link-local address in accordance to
+ * `dist/tools/ethos/setup_network.sh`.
+ *
+ * @note    This might not be necessary with a properly set-up DHCPv6 server
+ *          (automatically configures a route for the delegated prefix) and
+ *          upstream router (sends periodic router advertisements).
+ *
+ * @param[in] upstream_netif    The upstream netif  The upstream netif
+ */
+static void _configure_upstream_netif(gnrc_netif_t *upstream_netif)
+{
+    if (IS_ACTIVE(CONFIG_GNRC_DHCPV6_CLIENT_6LBR_STATIC_ROUTE)) {
+        ipv6_addr_t addr = {
+                .u8 = { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }
+            };
+
+        /* set default route to host machine (as set-up in setup_network.sh) */
+        gnrc_ipv6_nib_ft_add(NULL, 0, &addr, upstream_netif->pid, 0);
+        /* set additional link-local address to provide a well-known next hop
+         * for static route configuration on the host machine */
+        addr.u8[15] = 2;
+        gnrc_netif_ipv6_addr_add(upstream_netif, &addr, 64, 0);
+    }
+}
+
+/**
+ * @brief   Configures all 6LoWPAN interfaces to request a 64-bit prefix
+ */
+static void _configure_dhcpv6_client(void)
+{
+    gnrc_netif_t *netif = NULL;
+    while ((netif = gnrc_netif_iter(netif))) {
+        if (gnrc_netif_is_6lo(netif)) {
+            dhcpv6_client_req_ia_pd(netif->pid, 64U);
+        }
+    }
+}
+
+/**
+ * @brief   The DHCPv6 client thread
+ */
+static void *_dhcpv6_cl_6lbr_thread(void *args)
+{
+    event_queue_t event_queue;
+    gnrc_netif_t *upstream_netif = _find_upstream_netif();
+
+    (void)args;
+    if (upstream_netif == NULL) {
+        LOG_ERROR("DHCPv6: No upstream interface found!\n");
+        return NULL;
+    }
+    _configure_upstream_netif(upstream_netif);
+    /* initialize client event queue */
+    event_queue_init(&event_queue);
+    /* initialize DHCPv6 client on border interface */
+    dhcpv6_client_init(&event_queue, upstream_netif->pid);
+    /* configure client to request prefix delegation for WPAN interfaces */
+    _configure_dhcpv6_client();
+    /* start DHCPv6 client */
+    dhcpv6_client_start();
+    /* start event loop of DHCPv6 client */
+    event_loop(&event_queue);   /* never returns */
+    return NULL;
+}
+
+void gnrc_dhcpv6_client_6lbr_init(void)
+{
+    /* start DHCPv6 client thread to request prefix for WPAN */
+    thread_create(_stack, DHCPV6_CLIENT_STACK_SIZE,
+                  DHCPV6_CLIENT_PRIORITY,
+                  THREAD_CREATE_STACKTEST,
+                  _dhcpv6_cl_6lbr_thread, NULL, "dhcpv6-client");
+}
+
+/** @} */