root/net/6lowpan/ndisc.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Authors:
 * (C) 2016 Pengutronix, Alexander Aring <aar@pengutronix.de>
 */

#include <net/6lowpan.h>
#include <net/addrconf.h>
#include <net/ndisc.h>

#include "6lowpan_i.h"

#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
#define NDISC_802154_SHORT_ADDR_LENGTH  1
static int lowpan_ndisc_parse_802154_options(const struct net_device *dev,
                                             struct nd_opt_hdr *nd_opt,
                                             struct ndisc_options *ndopts)
{
        switch (nd_opt->nd_opt_len) {
        case NDISC_802154_SHORT_ADDR_LENGTH:
                if (ndopts->nd_802154_opt_array[nd_opt->nd_opt_type])
                        net_dbg_ratelimited("%s: duplicated short addr ND6 option found: type=%d\n",
                                            __func__, nd_opt->nd_opt_type);
                else
                        ndopts->nd_802154_opt_array[nd_opt->nd_opt_type] = nd_opt;
                return 1;
        default:
                /* all others will be handled by ndisc IPv6 option parsing */
                return 0;
        }
}

static int lowpan_ndisc_parse_options(const struct net_device *dev,
                                      struct nd_opt_hdr *nd_opt,
                                      struct ndisc_options *ndopts)
{
        if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
                return 0;

        switch (nd_opt->nd_opt_type) {
        case ND_OPT_SOURCE_LL_ADDR:
        case ND_OPT_TARGET_LL_ADDR:
                return lowpan_ndisc_parse_802154_options(dev, nd_opt, ndopts);
        default:
                return 0;
        }
}

static void lowpan_ndisc_802154_update(struct neighbour *n, u32 flags,
                                       u8 icmp6_type,
                                       const struct ndisc_options *ndopts)
{
        struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
        u8 *lladdr_short = NULL;

        switch (icmp6_type) {
        case NDISC_ROUTER_SOLICITATION:
        case NDISC_ROUTER_ADVERTISEMENT:
        case NDISC_NEIGHBOUR_SOLICITATION:
                if (ndopts->nd_802154_opts_src_lladdr) {
                        lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_src_lladdr,
                                                             IEEE802154_SHORT_ADDR_LEN, 0);
                        if (!lladdr_short) {
                                net_dbg_ratelimited("NA: invalid short link-layer address length\n");
                                return;
                        }
                }
                break;
        case NDISC_REDIRECT:
        case NDISC_NEIGHBOUR_ADVERTISEMENT:
                if (ndopts->nd_802154_opts_tgt_lladdr) {
                        lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_tgt_lladdr,
                                                             IEEE802154_SHORT_ADDR_LEN, 0);
                        if (!lladdr_short) {
                                net_dbg_ratelimited("NA: invalid short link-layer address length\n");
                                return;
                        }
                }
                break;
        default:
                break;
        }

        write_lock_bh(&n->lock);
        if (lladdr_short) {
                ieee802154_be16_to_le16(&neigh->short_addr, lladdr_short);
                if (!lowpan_802154_is_valid_src_short_addr(neigh->short_addr))
                        neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
        }
        write_unlock_bh(&n->lock);
}

static void lowpan_ndisc_update(const struct net_device *dev,
                                struct neighbour *n, u32 flags, u8 icmp6_type,
                                const struct ndisc_options *ndopts)
{
        if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
                return;

        /* react on overrides only. TODO check if this is really right. */
        if (flags & NEIGH_UPDATE_F_OVERRIDE)
                lowpan_ndisc_802154_update(n, flags, icmp6_type, ndopts);
}

static int lowpan_ndisc_opt_addr_space(const struct net_device *dev,
                                       u8 icmp6_type, struct neighbour *neigh,
                                       u8 *ha_buf, u8 **ha)
{
        struct lowpan_802154_neigh *n;
        struct wpan_dev *wpan_dev;
        int addr_space = 0;

        if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
                return 0;

        switch (icmp6_type) {
        case NDISC_REDIRECT:
                n = lowpan_802154_neigh(neighbour_priv(neigh));

                read_lock_bh(&neigh->lock);
                if (lowpan_802154_is_valid_src_short_addr(n->short_addr)) {
                        memcpy(ha_buf, &n->short_addr,
                               IEEE802154_SHORT_ADDR_LEN);
                        read_unlock_bh(&neigh->lock);
                        addr_space += __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
                        *ha = ha_buf;
                } else {
                        read_unlock_bh(&neigh->lock);
                }
                break;
        case NDISC_NEIGHBOUR_ADVERTISEMENT:
        case NDISC_NEIGHBOUR_SOLICITATION:
        case NDISC_ROUTER_SOLICITATION:
                wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;

                if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr))
                        addr_space = __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
                break;
        default:
                break;
        }

        return addr_space;
}

static void lowpan_ndisc_fill_addr_option(const struct net_device *dev,
                                          struct sk_buff *skb, u8 icmp6_type,
                                          const u8 *ha)
{
        struct wpan_dev *wpan_dev;
        __be16 short_addr;
        u8 opt_type;

        if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
                return;

        switch (icmp6_type) {
        case NDISC_REDIRECT:
                if (ha) {
                        ieee802154_le16_to_be16(&short_addr, ha);
                        __ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
                                                 &short_addr,
                                                 IEEE802154_SHORT_ADDR_LEN, 0);
                }
                return;
        case NDISC_NEIGHBOUR_ADVERTISEMENT:
                opt_type = ND_OPT_TARGET_LL_ADDR;
                break;
        case NDISC_ROUTER_SOLICITATION:
        case NDISC_NEIGHBOUR_SOLICITATION:
                opt_type = ND_OPT_SOURCE_LL_ADDR;
                break;
        default:
                return;
        }

        wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;

        if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
                ieee802154_le16_to_be16(&short_addr,
                                        &wpan_dev->short_addr);
                __ndisc_fill_addr_option(skb, opt_type, &short_addr,
                                         IEEE802154_SHORT_ADDR_LEN, 0);
        }
}

static void lowpan_ndisc_prefix_rcv_add_addr(struct net *net,
                                             struct net_device *dev,
                                             const struct prefix_info *pinfo,
                                             struct inet6_dev *in6_dev,
                                             struct in6_addr *addr,
                                             int addr_type, u32 addr_flags,
                                             bool sllao, bool tokenized,
                                             __u32 valid_lft,
                                             u32 prefered_lft,
                                             bool dev_addr_generated)
{
        int err;

        /* generates short based address for RA PIO's */
        if (lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154) && dev_addr_generated &&
            !addrconf_ifid_802154_6lowpan(addr->s6_addr + 8, dev)) {
                err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
                                                   addr, addr_type, addr_flags,
                                                   sllao, tokenized, valid_lft,
                                                   prefered_lft);
                if (err)
                        net_dbg_ratelimited("RA: could not add a short address based address for prefix: %pI6c\n",
                                            &pinfo->prefix);
        }
}
#endif

const struct ndisc_ops lowpan_ndisc_ops = {
#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
        .parse_options          = lowpan_ndisc_parse_options,
        .update                 = lowpan_ndisc_update,
        .opt_addr_space         = lowpan_ndisc_opt_addr_space,
        .fill_addr_option       = lowpan_ndisc_fill_addr_option,
        .prefix_rcv_add_addr    = lowpan_ndisc_prefix_rcv_add_addr,
#endif
};