RIOT/sys/net/gnrc/application_layer/uhcpc/gnrc_uhcpc.c

/*
 * Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
 *
 * 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.
 */

#include "net/gnrc/ipv6/nib.h"
#include "net/gnrc/ipv6.h"
#include "net/gnrc/netapi.h"
#include "net/gnrc/netif.h"
#ifdef MODULE_GNRC_RPL
#include "net/gnrc/rpl.h"
#endif
#ifdef MODULE_GNRC_SIXLOWPAN_CTX
#include "net/gnrc/sixlowpan/ctx.h"
#endif
#include "net/ipv6/addr.h"
#include "net/netdev.h"
#include "net/netopt.h"

#include "net/uhcp.h"
#include "log.h"
#include "fmt.h"

static kernel_pid_t gnrc_border_interface;
static kernel_pid_t gnrc_wireless_interface;

static void set_interface_roles(void)
{
    gnrc_netif_t *netif = NULL;

    while ((netif = gnrc_netif_iter(netif))) {
        kernel_pid_t dev = netif->pid;
        int is_wired = gnrc_netapi_get(dev, NETOPT_IS_WIRED, 0, NULL, 0);
        if ((!gnrc_border_interface) && (is_wired == 1)) {
            ipv6_addr_t addr, defroute = IPV6_ADDR_UNSPECIFIED;
            gnrc_border_interface = dev;

            ipv6_addr_from_str(&addr, "fe80::2");
            gnrc_netapi_set(dev, NETOPT_IPV6_ADDR, 64 << 8, &addr, sizeof(addr));
            ipv6_addr_from_str(&addr, "fe80::1");
            gnrc_ipv6_nib_ft_add(&defroute, IPV6_ADDR_BIT_LEN, &addr, dev, 0);
        }
        else if ((!gnrc_wireless_interface) && (is_wired != 1)) {
            gnrc_wireless_interface = dev;
        }

        if (gnrc_border_interface && gnrc_wireless_interface) {
            break;
        }
    }

    LOG_INFO("gnrc_uhcpc: Using %u as border interface and %u as wireless interface.\n", gnrc_border_interface, gnrc_wireless_interface);
}

static ipv6_addr_t _prefix;

#ifdef MODULE_GNRC_SIXLOWPAN_CTX
#define SIXLO_CTX_LTIME_MIN (60U)   /**< context lifetime in minutes */

static bool _ctx_match(const gnrc_sixlowpan_ctx_t *ctx,
                       const ipv6_addr_t *prefix, uint8_t prefix_len)
{
    return (ctx->prefix_len == prefix_len) &&
           (ipv6_addr_match_prefix(&ctx->prefix, prefix) >= prefix_len);
}

static void _update_6ctx(const ipv6_addr_t *prefix, uint8_t prefix_len)
{
    gnrc_sixlowpan_ctx_t *ctx = gnrc_sixlowpan_ctx_lookup_addr(prefix);
    uint8_t cid = 0;

    if (!_ctx_match(ctx, prefix, prefix_len)) {
        /* While the context is a prefix match, the defined prefix within the
         * context does not match => use new context */
        ctx = NULL;
    }
    else {
        cid = ctx->flags_id & GNRC_SIXLOWPAN_CTX_FLAGS_CID_MASK;
    }
    /* find first free context ID */
    if (ctx == NULL) {
        while (((ctx = gnrc_sixlowpan_ctx_lookup_id(cid)) != NULL) &&
               !_ctx_match(ctx, prefix, prefix_len)) {
            cid++;
        }
    }
    if (cid < GNRC_SIXLOWPAN_CTX_SIZE) {
        static ipv6_addr_t addr_str[IPV6_ADDR_MAX_STR_LEN];
        LOG_INFO("gnrc_uhcpc: uhcp_handle_prefix(): add compression context "
                 "%u for prefix %s/%u\n", cid,
                 ipv6_addr_to_str(addr_str, prefix, sizeof(addr_str)),
                 prefix_len);
        gnrc_sixlowpan_ctx_update(cid, (ipv6_addr_t *)prefix, prefix_len,
                                  SIXLO_CTX_LTIME_MIN, true);
    }
}
#endif

void uhcp_handle_prefix(uint8_t *prefix, uint8_t prefix_len, uint16_t lifetime, uint8_t *src, uhcp_iface_t iface)
{
    (void)prefix_len;
    (void)lifetime;
    (void)src;

    eui64_t iid;
    if (!gnrc_wireless_interface) {
        LOG_WARNING("gnrc_uhcpc: uhcp_handle_prefix(): received prefix, but don't know any wireless interface\n");
        return;
    }

    if ((kernel_pid_t)iface != gnrc_border_interface) {
        LOG_WARNING("gnrc_uhcpc: uhcp_handle_prefix(): received prefix from unexpected interface\n");
        return;
    }

    if (gnrc_netapi_get(gnrc_wireless_interface, NETOPT_IPV6_IID, 0, &iid,
                        sizeof(eui64_t)) >= 0) {
        ipv6_addr_set_aiid((ipv6_addr_t*)prefix, iid.uint8);
    }
    else {
        LOG_WARNING("gnrc_uhcpc: uhcp_handle_prefix(): cannot get IID of wireless interface\n");
        return;
    }

    if (ipv6_addr_equal(&_prefix, (ipv6_addr_t*)prefix)) {
        LOG_WARNING("gnrc_uhcpc: uhcp_handle_prefix(): got same prefix again\n");
#ifdef MODULE_GNRC_SIXLOWPAN_CTX
        /* always update 6LoWPAN compression context so it does not time out, we
         * can't just remove it anyway according to the RFC */
        _update_6ctx((ipv6_addr_t *)prefix, 64);
#endif
        return;
    }

    gnrc_netapi_set(gnrc_wireless_interface, NETOPT_IPV6_ADDR, (64 << 8),
        /* always update 6LoWPAN compression context so it does not time out, we
         * can't just remove it anyway according to the RFC */
                    prefix, sizeof(ipv6_addr_t));
#if defined(MODULE_GNRC_IPV6_NIB) && GNRC_IPV6_NIB_CONF_6LBR && \
    GNRC_IPV6_NIB_CONF_MULTIHOP_P6C
    gnrc_ipv6_nib_abr_add((ipv6_addr_t *)prefix);
#endif
#ifdef MODULE_GNRC_RPL
    gnrc_rpl_init(gnrc_wireless_interface);
    gnrc_rpl_instance_t *inst = gnrc_rpl_instance_get(GNRC_RPL_DEFAULT_INSTANCE);
    if (inst) {
        gnrc_rpl_instance_remove(inst);
    }
    gnrc_rpl_root_init(GNRC_RPL_DEFAULT_INSTANCE, (ipv6_addr_t*)prefix, false, false);
#endif
    gnrc_netapi_set(gnrc_wireless_interface, NETOPT_IPV6_ADDR_REMOVE, 0,
                    &_prefix, sizeof(_prefix));
    print_str("gnrc_uhcpc: uhcp_handle_prefix(): configured new prefix ");
    ipv6_addr_print((ipv6_addr_t*)prefix);
    puts("/64");

    if (!ipv6_addr_is_unspecified(&_prefix)) {
        gnrc_netapi_set(gnrc_wireless_interface, NETOPT_IPV6_ADDR_REMOVE, 0,
                        &_prefix, sizeof(_prefix));
#if defined(MODULE_GNRC_IPV6_NIB) && GNRC_IPV6_NIB_CONF_6LBR && \
    GNRC_IPV6_NIB_CONF_MULTIHOP_P6C
        gnrc_ipv6_nib_abr_del(&_prefix);
#endif
        print_str("gnrc_uhcpc: uhcp_handle_prefix(): removed old prefix ");
        ipv6_addr_print(&_prefix);
        puts("/64");
    }

#ifdef MODULE_GNRC_SIXLOWPAN_CTX
    /* update compression context last in case previous context was removed by
     * gnrc_ipv6_nib_abr_del() above */
    _update_6ctx((ipv6_addr_t *)prefix, 64);
#endif
    memcpy(&_prefix, prefix, 16);
}

extern void uhcp_client(uhcp_iface_t iface);

static char _uhcp_client_stack[THREAD_STACKSIZE_DEFAULT + THREAD_EXTRA_STACKSIZE_PRINTF];
static msg_t _uhcp_msg_queue[4];

static void* uhcp_client_thread(void *arg)
{
    (void)arg;

    msg_init_queue(_uhcp_msg_queue, ARRAY_SIZE(_uhcp_msg_queue));
    uhcp_client(gnrc_border_interface);
    return NULL;
}

void auto_init_gnrc_uhcpc(void)
{
    set_interface_roles();

    /* only start client if more than one interface is given */
    if (! (gnrc_border_interface && gnrc_wireless_interface)) {
        LOG_WARNING("gnrc_uhcpc: only one interface found, skipping setup.\n");
        return;
    }

    /* initiate uhcp client */
    thread_create(_uhcp_client_stack, sizeof(_uhcp_client_stack),
            THREAD_PRIORITY_MAIN - 1, THREAD_CREATE_STACKTEST,
            uhcp_client_thread, NULL, "uhcp");
}