root/net/nfc/llcp_core.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2011  Intel Corporation. All rights reserved.
 * Copyright (C) 2014 Marvell International Ltd.
 */

#define pr_fmt(fmt) "llcp: %s: " fmt, __func__

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/nfc.h>

#include "nfc.h"
#include "llcp.h"

static u8 llcp_magic[3] = {0x46, 0x66, 0x6d};

static LIST_HEAD(llcp_devices);
/* Protects llcp_devices list */
static DEFINE_SPINLOCK(llcp_devices_lock);

static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb);

void nfc_llcp_sock_link(struct llcp_sock_list *l, struct sock *sk)
{
        write_lock(&l->lock);
        sk_add_node(sk, &l->head);
        write_unlock(&l->lock);
}

void nfc_llcp_sock_unlink(struct llcp_sock_list *l, struct sock *sk)
{
        write_lock(&l->lock);
        sk_del_node_init(sk);
        write_unlock(&l->lock);
}

void nfc_llcp_socket_remote_param_init(struct nfc_llcp_sock *sock)
{
        sock->remote_rw = LLCP_DEFAULT_RW;
        sock->remote_miu = LLCP_MAX_MIU + 1;
}

static void nfc_llcp_socket_purge(struct nfc_llcp_sock *sock)
{
        struct nfc_llcp_local *local = sock->local;
        struct sk_buff *s, *tmp;

        skb_queue_purge(&sock->tx_queue);
        skb_queue_purge(&sock->tx_pending_queue);

        if (local == NULL)
                return;

        /* Search for local pending SKBs that are related to this socket */
        skb_queue_walk_safe(&local->tx_queue, s, tmp) {
                if (s->sk != &sock->sk)
                        continue;

                skb_unlink(s, &local->tx_queue);
                kfree_skb(s);
        }
}

static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device,
                                    int err)
{
        struct sock *sk;
        struct hlist_node *tmp;
        struct nfc_llcp_sock *llcp_sock;

        skb_queue_purge(&local->tx_queue);

        write_lock(&local->sockets.lock);

        sk_for_each_safe(sk, tmp, &local->sockets.head) {
                llcp_sock = nfc_llcp_sock(sk);

                bh_lock_sock(sk);

                nfc_llcp_socket_purge(llcp_sock);

                if (sk->sk_state == LLCP_CONNECTED)
                        nfc_put_device(llcp_sock->dev);

                if (sk->sk_state == LLCP_LISTEN) {
                        struct nfc_llcp_sock *lsk, *n;
                        struct sock *accept_sk;

                        list_for_each_entry_safe(lsk, n,
                                                 &llcp_sock->accept_queue,
                                                 accept_queue) {
                                accept_sk = &lsk->sk;
                                bh_lock_sock(accept_sk);

                                nfc_llcp_accept_unlink(accept_sk);

                                if (err)
                                        accept_sk->sk_err = err;
                                accept_sk->sk_state = LLCP_CLOSED;
                                accept_sk->sk_state_change(sk);

                                bh_unlock_sock(accept_sk);
                        }
                }

                if (err)
                        sk->sk_err = err;
                sk->sk_state = LLCP_CLOSED;
                sk->sk_state_change(sk);

                bh_unlock_sock(sk);

                sk_del_node_init(sk);
        }

        write_unlock(&local->sockets.lock);

        /* If we still have a device, we keep the RAW sockets alive */
        if (device == true)
                return;

        write_lock(&local->raw_sockets.lock);

        sk_for_each_safe(sk, tmp, &local->raw_sockets.head) {
                llcp_sock = nfc_llcp_sock(sk);

                bh_lock_sock(sk);

                nfc_llcp_socket_purge(llcp_sock);

                if (err)
                        sk->sk_err = err;
                sk->sk_state = LLCP_CLOSED;
                sk->sk_state_change(sk);

                bh_unlock_sock(sk);

                sk_del_node_init(sk);
        }

        write_unlock(&local->raw_sockets.lock);
}

static struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local)
{
        /* Since using nfc_llcp_local may result in usage of nfc_dev, whenever
         * we hold a reference to local, we also need to hold a reference to
         * the device to avoid UAF.
         */
        if (!nfc_get_device(local->dev->idx))
                return NULL;

        kref_get(&local->ref);

        return local;
}

static void local_cleanup(struct nfc_llcp_local *local)
{
        nfc_llcp_socket_release(local, false, ENXIO);
        timer_delete_sync(&local->link_timer);
        skb_queue_purge(&local->tx_queue);
        cancel_work_sync(&local->tx_work);
        cancel_work_sync(&local->rx_work);
        cancel_work_sync(&local->timeout_work);
        kfree_skb(local->rx_pending);
        local->rx_pending = NULL;
        timer_delete_sync(&local->sdreq_timer);
        cancel_work_sync(&local->sdreq_timeout_work);
        nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
}

static void local_release(struct kref *ref)
{
        struct nfc_llcp_local *local;

        local = container_of(ref, struct nfc_llcp_local, ref);

        local_cleanup(local);
        kfree(local);
}

int nfc_llcp_local_put(struct nfc_llcp_local *local)
{
        struct nfc_dev *dev;
        int ret;

        if (local == NULL)
                return 0;

        dev = local->dev;

        ret = kref_put(&local->ref, local_release);
        nfc_put_device(dev);

        return ret;
}

static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local,
                                               u8 ssap, u8 dsap)
{
        struct sock *sk;
        struct nfc_llcp_sock *llcp_sock, *tmp_sock;

        pr_debug("ssap dsap %d %d\n", ssap, dsap);

        if (ssap == 0 && dsap == 0)
                return NULL;

        read_lock(&local->sockets.lock);

        llcp_sock = NULL;

        sk_for_each(sk, &local->sockets.head) {
                tmp_sock = nfc_llcp_sock(sk);

                if (tmp_sock->ssap == ssap && tmp_sock->dsap == dsap) {
                        llcp_sock = tmp_sock;
                        sock_hold(&llcp_sock->sk);
                        break;
                }
        }

        read_unlock(&local->sockets.lock);

        return llcp_sock;
}

static void nfc_llcp_sock_put(struct nfc_llcp_sock *sock)
{
        sock_put(&sock->sk);
}

static void nfc_llcp_timeout_work(struct work_struct *work)
{
        struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
                                                    timeout_work);

        nfc_dep_link_down(local->dev);
}

static void nfc_llcp_symm_timer(struct timer_list *t)
{
        struct nfc_llcp_local *local = timer_container_of(local, t,
                                                          link_timer);

        pr_err("SYMM timeout\n");

        schedule_work(&local->timeout_work);
}

static void nfc_llcp_sdreq_timeout_work(struct work_struct *work)
{
        unsigned long time;
        HLIST_HEAD(nl_sdres_list);
        struct hlist_node *n;
        struct nfc_llcp_sdp_tlv *sdp;
        struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
                                                    sdreq_timeout_work);

        mutex_lock(&local->sdreq_lock);

        time = jiffies - msecs_to_jiffies(3 * local->remote_lto);

        hlist_for_each_entry_safe(sdp, n, &local->pending_sdreqs, node) {
                if (time_after(sdp->time, time))
                        continue;

                sdp->sap = LLCP_SDP_UNBOUND;

                hlist_del(&sdp->node);

                hlist_add_head(&sdp->node, &nl_sdres_list);
        }

        if (!hlist_empty(&local->pending_sdreqs))
                mod_timer(&local->sdreq_timer,
                          jiffies + msecs_to_jiffies(3 * local->remote_lto));

        mutex_unlock(&local->sdreq_lock);

        if (!hlist_empty(&nl_sdres_list))
                nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
}

static void nfc_llcp_sdreq_timer(struct timer_list *t)
{
        struct nfc_llcp_local *local = timer_container_of(local, t,
                                                          sdreq_timer);

        schedule_work(&local->sdreq_timeout_work);
}

struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
{
        struct nfc_llcp_local *local;
        struct nfc_llcp_local *res = NULL;

        spin_lock(&llcp_devices_lock);
        list_for_each_entry(local, &llcp_devices, list)
                if (local->dev == dev) {
                        res = nfc_llcp_local_get(local);
                        break;
                }
        spin_unlock(&llcp_devices_lock);

        return res;
}

static struct nfc_llcp_local *nfc_llcp_remove_local(struct nfc_dev *dev)
{
        struct nfc_llcp_local *local, *tmp;

        spin_lock(&llcp_devices_lock);
        list_for_each_entry_safe(local, tmp, &llcp_devices, list)
                if (local->dev == dev) {
                        spin_lock(&local->tx_queue.lock);
                        list_del_init(&local->list);
                        spin_unlock(&local->tx_queue.lock);
                        spin_unlock(&llcp_devices_lock);
                        return local;
                }
        spin_unlock(&llcp_devices_lock);

        pr_warn("Shutting down device not found\n");

        return NULL;
}

static char *wks[] = {
        NULL,
        NULL, /* SDP */
        "urn:nfc:sn:ip",
        "urn:nfc:sn:obex",
        "urn:nfc:sn:snep",
};

static int nfc_llcp_wks_sap(const char *service_name, size_t service_name_len)
{
        int sap, num_wks;

        pr_debug("%s\n", service_name);

        if (service_name == NULL)
                return -EINVAL;

        num_wks = ARRAY_SIZE(wks);

        for (sap = 0; sap < num_wks; sap++) {
                if (wks[sap] == NULL)
                        continue;

                if (strncmp(wks[sap], service_name, service_name_len) == 0)
                        return sap;
        }

        return -EINVAL;
}

static
struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local,
                                            const u8 *sn, size_t sn_len,
                                            bool needref)
{
        struct sock *sk;
        struct nfc_llcp_sock *llcp_sock, *tmp_sock;

        pr_debug("sn %zd %p\n", sn_len, sn);

        if (sn == NULL || sn_len == 0)
                return NULL;

        read_lock(&local->sockets.lock);

        llcp_sock = NULL;

        sk_for_each(sk, &local->sockets.head) {
                tmp_sock = nfc_llcp_sock(sk);

                pr_debug("llcp sock %p\n", tmp_sock);

                if (tmp_sock->sk.sk_type == SOCK_STREAM &&
                    tmp_sock->sk.sk_state != LLCP_LISTEN)
                        continue;

                if (tmp_sock->sk.sk_type == SOCK_DGRAM &&
                    tmp_sock->sk.sk_state != LLCP_BOUND)
                        continue;

                if (tmp_sock->service_name == NULL ||
                    tmp_sock->service_name_len == 0)
                        continue;

                if (tmp_sock->service_name_len != sn_len)
                        continue;

                if (memcmp(sn, tmp_sock->service_name, sn_len) == 0) {
                        llcp_sock = tmp_sock;
                        if (needref)
                                sock_hold(&llcp_sock->sk);
                        break;
                }
        }

        read_unlock(&local->sockets.lock);

        pr_debug("Found llcp sock %p\n", llcp_sock);

        return llcp_sock;
}

u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
                         struct nfc_llcp_sock *sock)
{
        mutex_lock(&local->sdp_lock);

        if (sock->service_name != NULL && sock->service_name_len > 0) {
                int ssap = nfc_llcp_wks_sap(sock->service_name,
                                            sock->service_name_len);

                if (ssap > 0) {
                        pr_debug("WKS %d\n", ssap);

                        /* This is a WKS, let's check if it's free */
                        if (test_bit(ssap, &local->local_wks)) {
                                mutex_unlock(&local->sdp_lock);

                                return LLCP_SAP_MAX;
                        }

                        set_bit(ssap, &local->local_wks);
                        mutex_unlock(&local->sdp_lock);

                        return ssap;
                }

                /*
                 * Check if there already is a non WKS socket bound
                 * to this service name.
                 */
                if (nfc_llcp_sock_from_sn(local, sock->service_name,
                                          sock->service_name_len,
                                          false) != NULL) {
                        mutex_unlock(&local->sdp_lock);

                        return LLCP_SAP_MAX;
                }

                mutex_unlock(&local->sdp_lock);

                return LLCP_SDP_UNBOUND;

        } else if (sock->ssap != 0 && sock->ssap < LLCP_WKS_NUM_SAP) {
                if (!test_bit(sock->ssap, &local->local_wks)) {
                        set_bit(sock->ssap, &local->local_wks);
                        mutex_unlock(&local->sdp_lock);

                        return sock->ssap;
                }
        }

        mutex_unlock(&local->sdp_lock);

        return LLCP_SAP_MAX;
}

u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local)
{
        u8 local_ssap;

        mutex_lock(&local->sdp_lock);

        local_ssap = find_first_zero_bit(&local->local_sap, LLCP_LOCAL_NUM_SAP);
        if (local_ssap == LLCP_LOCAL_NUM_SAP) {
                mutex_unlock(&local->sdp_lock);
                return LLCP_SAP_MAX;
        }

        set_bit(local_ssap, &local->local_sap);

        mutex_unlock(&local->sdp_lock);

        return local_ssap + LLCP_LOCAL_SAP_OFFSET;
}

void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap)
{
        u8 local_ssap;
        unsigned long *sdp;

        if (ssap < LLCP_WKS_NUM_SAP) {
                local_ssap = ssap;
                sdp = &local->local_wks;
        } else if (ssap < LLCP_LOCAL_NUM_SAP) {
                atomic_t *client_cnt;

                local_ssap = ssap - LLCP_WKS_NUM_SAP;
                sdp = &local->local_sdp;
                client_cnt = &local->local_sdp_cnt[local_ssap];

                pr_debug("%d clients\n", atomic_read(client_cnt));

                mutex_lock(&local->sdp_lock);

                if (atomic_dec_and_test(client_cnt)) {
                        struct nfc_llcp_sock *l_sock;

                        pr_debug("No more clients for SAP %d\n", ssap);

                        clear_bit(local_ssap, sdp);

                        /* Find the listening sock and set it back to UNBOUND */
                        l_sock = nfc_llcp_sock_get(local, ssap, LLCP_SAP_SDP);
                        if (l_sock) {
                                l_sock->ssap = LLCP_SDP_UNBOUND;
                                nfc_llcp_sock_put(l_sock);
                        }
                }

                mutex_unlock(&local->sdp_lock);

                return;
        } else if (ssap < LLCP_MAX_SAP) {
                local_ssap = ssap - LLCP_LOCAL_NUM_SAP;
                sdp = &local->local_sap;
        } else {
                return;
        }

        mutex_lock(&local->sdp_lock);

        clear_bit(local_ssap, sdp);

        mutex_unlock(&local->sdp_lock);
}

static u8 nfc_llcp_reserve_sdp_ssap(struct nfc_llcp_local *local)
{
        u8 ssap;

        mutex_lock(&local->sdp_lock);

        ssap = find_first_zero_bit(&local->local_sdp, LLCP_SDP_NUM_SAP);
        if (ssap == LLCP_SDP_NUM_SAP) {
                mutex_unlock(&local->sdp_lock);

                return LLCP_SAP_MAX;
        }

        pr_debug("SDP ssap %d\n", LLCP_WKS_NUM_SAP + ssap);

        set_bit(ssap, &local->local_sdp);

        mutex_unlock(&local->sdp_lock);

        return LLCP_WKS_NUM_SAP + ssap;
}

static int nfc_llcp_build_gb(struct nfc_llcp_local *local)
{
        u8 *gb_cur, version, version_length;
        u8 lto_length, wks_length, miux_length;
        const u8 *version_tlv = NULL, *lto_tlv = NULL,
           *wks_tlv = NULL, *miux_tlv = NULL;
        __be16 wks = cpu_to_be16(local->local_wks);
        u8 gb_len = 0;
        int ret = 0;

        version = LLCP_VERSION_11;
        version_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &version,
                                         1, &version_length);
        if (!version_tlv) {
                ret = -ENOMEM;
                goto out;
        }
        gb_len += version_length;

        lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &local->lto, 1, &lto_length);
        if (!lto_tlv) {
                ret = -ENOMEM;
                goto out;
        }
        gb_len += lto_length;

        pr_debug("Local wks 0x%lx\n", local->local_wks);
        wks_tlv = nfc_llcp_build_tlv(LLCP_TLV_WKS, (u8 *)&wks, 2, &wks_length);
        if (!wks_tlv) {
                ret = -ENOMEM;
                goto out;
        }
        gb_len += wks_length;

        miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
                                      &miux_length);
        if (!miux_tlv) {
                ret = -ENOMEM;
                goto out;
        }
        gb_len += miux_length;

        gb_len += ARRAY_SIZE(llcp_magic);

        if (gb_len > NFC_MAX_GT_LEN) {
                ret = -EINVAL;
                goto out;
        }

        gb_cur = local->gb;

        memcpy(gb_cur, llcp_magic, ARRAY_SIZE(llcp_magic));
        gb_cur += ARRAY_SIZE(llcp_magic);

        memcpy(gb_cur, version_tlv, version_length);
        gb_cur += version_length;

        memcpy(gb_cur, lto_tlv, lto_length);
        gb_cur += lto_length;

        memcpy(gb_cur, wks_tlv, wks_length);
        gb_cur += wks_length;

        memcpy(gb_cur, miux_tlv, miux_length);
        gb_cur += miux_length;

        local->gb_len = gb_len;

out:
        kfree(version_tlv);
        kfree(lto_tlv);
        kfree(wks_tlv);
        kfree(miux_tlv);

        return ret;
}

u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len)
{
        struct nfc_llcp_local *local;

        local = nfc_llcp_find_local(dev);
        if (local == NULL) {
                *general_bytes_len = 0;
                return NULL;
        }

        nfc_llcp_build_gb(local);

        *general_bytes_len = local->gb_len;

        nfc_llcp_local_put(local);

        return local->gb;
}

int nfc_llcp_set_remote_gb(struct nfc_dev *dev, const u8 *gb, u8 gb_len)
{
        struct nfc_llcp_local *local;
        int err;

        if (gb_len < 3 || gb_len > NFC_MAX_GT_LEN)
                return -EINVAL;

        local = nfc_llcp_find_local(dev);
        if (local == NULL) {
                pr_err("No LLCP device\n");
                return -ENODEV;
        }

        memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
        memcpy(local->remote_gb, gb, gb_len);
        local->remote_gb_len = gb_len;

        if (memcmp(local->remote_gb, llcp_magic, 3)) {
                pr_err("MAC does not support LLCP\n");
                err = -EINVAL;
                goto out;
        }

        err = nfc_llcp_parse_gb_tlv(local,
                                     &local->remote_gb[3],
                                     local->remote_gb_len - 3);
out:
        nfc_llcp_local_put(local);
        return err;
}

static u8 nfc_llcp_dsap(const struct sk_buff *pdu)
{
        return (pdu->data[0] & 0xfc) >> 2;
}

static u8 nfc_llcp_ptype(const struct sk_buff *pdu)
{
        return ((pdu->data[0] & 0x03) << 2) | ((pdu->data[1] & 0xc0) >> 6);
}

static u8 nfc_llcp_ssap(const struct sk_buff *pdu)
{
        return pdu->data[1] & 0x3f;
}

static u8 nfc_llcp_ns(const struct sk_buff *pdu)
{
        return pdu->data[2] >> 4;
}

static u8 nfc_llcp_nr(const struct sk_buff *pdu)
{
        return pdu->data[2] & 0xf;
}

static void nfc_llcp_set_nrns(struct nfc_llcp_sock *sock, struct sk_buff *pdu)
{
        pdu->data[2] = (sock->send_n << 4) | (sock->recv_n);
        sock->send_n = (sock->send_n + 1) % 16;
        sock->recv_ack_n = (sock->recv_n - 1) % 16;
}

void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
                               struct sk_buff *skb, u8 direction)
{
        struct sk_buff *skb_copy = NULL, *nskb;
        struct sock *sk;
        u8 *data;

        read_lock(&local->raw_sockets.lock);

        sk_for_each(sk, &local->raw_sockets.head) {
                if (sk->sk_state != LLCP_BOUND)
                        continue;

                if (skb_copy == NULL) {
                        skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
                                                      GFP_ATOMIC, true);

                        if (skb_copy == NULL)
                                continue;

                        data = skb_push(skb_copy, NFC_RAW_HEADER_SIZE);

                        data[0] = local->dev ? local->dev->idx : 0xFF;
                        data[1] = direction & 0x01;
                        data[1] |= (RAW_PAYLOAD_LLCP << 1);
                }

                nskb = skb_clone(skb_copy, GFP_ATOMIC);
                if (!nskb)
                        continue;

                if (sock_queue_rcv_skb(sk, nskb))
                        kfree_skb(nskb);
        }

        read_unlock(&local->raw_sockets.lock);

        kfree_skb(skb_copy);
}

static void nfc_llcp_tx_work(struct work_struct *work)
{
        struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
                                                    tx_work);
        struct sk_buff *skb;
        struct sock *sk;
        struct nfc_llcp_sock *llcp_sock;

        skb = skb_dequeue(&local->tx_queue);
        if (skb != NULL) {
                sk = skb->sk;
                llcp_sock = nfc_llcp_sock(sk);

                if (llcp_sock == NULL && nfc_llcp_ptype(skb) == LLCP_PDU_I) {
                        kfree_skb(skb);
                        nfc_llcp_send_symm(local->dev);
                } else if (llcp_sock && !llcp_sock->remote_ready) {
                        skb_queue_head(&local->tx_queue, skb);
                        nfc_llcp_send_symm(local->dev);
                } else {
                        struct sk_buff *copy_skb = NULL;
                        u8 ptype = nfc_llcp_ptype(skb);
                        int ret;

                        pr_debug("Sending pending skb\n");
                        print_hex_dump_debug("LLCP Tx: ", DUMP_PREFIX_OFFSET,
                                             16, 1, skb->data, skb->len, true);

                        if (ptype == LLCP_PDU_I)
                                copy_skb = skb_copy(skb, GFP_ATOMIC);

                        __net_timestamp(skb);

                        nfc_llcp_send_to_raw_sock(local, skb,
                                                  NFC_DIRECTION_TX);

                        ret = nfc_data_exchange(local->dev, local->target_idx,
                                                skb, nfc_llcp_recv, local);

                        if (ret) {
                                kfree_skb(copy_skb);
                                goto out;
                        }

                        if (ptype == LLCP_PDU_I && copy_skb)
                                skb_queue_tail(&llcp_sock->tx_pending_queue,
                                               copy_skb);
                }
        } else {
                nfc_llcp_send_symm(local->dev);
        }

out:
        mod_timer(&local->link_timer,
                  jiffies + msecs_to_jiffies(2 * local->remote_lto));
}

static struct nfc_llcp_sock *nfc_llcp_connecting_sock_get(struct nfc_llcp_local *local,
                                                          u8 ssap)
{
        struct sock *sk;
        struct nfc_llcp_sock *llcp_sock;

        read_lock(&local->connecting_sockets.lock);

        sk_for_each(sk, &local->connecting_sockets.head) {
                llcp_sock = nfc_llcp_sock(sk);

                if (llcp_sock->ssap == ssap) {
                        sock_hold(&llcp_sock->sk);
                        goto out;
                }
        }

        llcp_sock = NULL;

out:
        read_unlock(&local->connecting_sockets.lock);

        return llcp_sock;
}

static struct nfc_llcp_sock *nfc_llcp_sock_get_sn(struct nfc_llcp_local *local,
                                                  const u8 *sn, size_t sn_len)
{
        return nfc_llcp_sock_from_sn(local, sn, sn_len, true);
}

static const u8 *nfc_llcp_connect_sn(const struct sk_buff *skb, size_t *sn_len)
{
        u8 type, length;
        const u8 *tlv = &skb->data[2];
        size_t tlv_array_len = skb->len - LLCP_HEADER_SIZE, offset = 0;

        while (offset < tlv_array_len) {
                type = tlv[0];
                length = tlv[1];

                pr_debug("type 0x%x length %d\n", type, length);

                if (type == LLCP_TLV_SN) {
                        *sn_len = length;
                        return &tlv[2];
                }

                offset += length + 2;
                tlv += length + 2;
        }

        return NULL;
}

static void nfc_llcp_recv_ui(struct nfc_llcp_local *local,
                             struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        struct nfc_llcp_ui_cb *ui_cb;
        u8 dsap, ssap;

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        ui_cb = nfc_llcp_ui_skb_cb(skb);
        ui_cb->dsap = dsap;
        ui_cb->ssap = ssap;

        pr_debug("%d %d\n", dsap, ssap);

        /* We're looking for a bound socket, not a client one */
        llcp_sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
        if (llcp_sock == NULL || llcp_sock->sk.sk_type != SOCK_DGRAM)
                return;

        /* There is no sequence with UI frames */
        skb_pull(skb, LLCP_HEADER_SIZE);
        if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
                /*
                 * UI frames will be freed from the socket layer, so we
                 * need to keep them alive until someone receives them.
                 */
                skb_get(skb);
        } else {
                pr_err("Receive queue is full\n");
        }

        nfc_llcp_sock_put(llcp_sock);
}

static void nfc_llcp_recv_connect(struct nfc_llcp_local *local,
                                  const struct sk_buff *skb)
{
        struct sock *new_sk, *parent;
        struct nfc_llcp_sock *sock, *new_sock;
        u8 dsap, ssap, reason;

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        pr_debug("%d %d\n", dsap, ssap);

        if (dsap != LLCP_SAP_SDP) {
                sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
                if (sock == NULL || sock->sk.sk_state != LLCP_LISTEN) {
                        reason = LLCP_DM_NOBOUND;
                        goto fail;
                }
        } else {
                const u8 *sn;
                size_t sn_len;

                sn = nfc_llcp_connect_sn(skb, &sn_len);
                if (sn == NULL) {
                        reason = LLCP_DM_NOBOUND;
                        goto fail;
                }

                pr_debug("Service name length %zu\n", sn_len);

                sock = nfc_llcp_sock_get_sn(local, sn, sn_len);
                if (sock == NULL) {
                        reason = LLCP_DM_NOBOUND;
                        goto fail;
                }
        }

        lock_sock(&sock->sk);

        parent = &sock->sk;

        if (sk_acceptq_is_full(parent)) {
                reason = LLCP_DM_REJ;
                release_sock(&sock->sk);
                sock_put(&sock->sk);
                goto fail;
        }

        if (sock->ssap == LLCP_SDP_UNBOUND) {
                u8 ssap = nfc_llcp_reserve_sdp_ssap(local);

                pr_debug("First client, reserving %d\n", ssap);

                if (ssap == LLCP_SAP_MAX) {
                        reason = LLCP_DM_REJ;
                        release_sock(&sock->sk);
                        sock_put(&sock->sk);
                        goto fail;
                }

                sock->ssap = ssap;
        }

        new_sk = nfc_llcp_sock_alloc(NULL, parent->sk_type, GFP_ATOMIC, 0);
        if (new_sk == NULL) {
                reason = LLCP_DM_REJ;
                release_sock(&sock->sk);
                sock_put(&sock->sk);
                goto fail;
        }

        new_sock = nfc_llcp_sock(new_sk);

        new_sock->local = nfc_llcp_local_get(local);
        if (!new_sock->local) {
                reason = LLCP_DM_REJ;
                sock_put(&new_sock->sk);
                release_sock(&sock->sk);
                sock_put(&sock->sk);
                goto fail;
        }

        new_sock->dev = local->dev;
        new_sock->rw = sock->rw;
        new_sock->miux = sock->miux;
        new_sock->nfc_protocol = sock->nfc_protocol;
        new_sock->dsap = ssap;
        new_sock->target_idx = local->target_idx;
        new_sock->parent = parent;
        new_sock->ssap = sock->ssap;
        if (sock->ssap < LLCP_LOCAL_NUM_SAP && sock->ssap >= LLCP_WKS_NUM_SAP) {
                atomic_t *client_count;

                pr_debug("reserved_ssap %d for %p\n", sock->ssap, new_sock);

                client_count =
                        &local->local_sdp_cnt[sock->ssap - LLCP_WKS_NUM_SAP];

                atomic_inc(client_count);
                new_sock->reserved_ssap = sock->ssap;
        }

        nfc_llcp_parse_connection_tlv(new_sock, &skb->data[LLCP_HEADER_SIZE],
                                      skb->len - LLCP_HEADER_SIZE);

        pr_debug("new sock %p sk %p\n", new_sock, &new_sock->sk);

        nfc_llcp_sock_link(&local->sockets, new_sk);

        nfc_llcp_accept_enqueue(&sock->sk, new_sk);

        nfc_get_device(local->dev->idx);

        new_sk->sk_state = LLCP_CONNECTED;

        /* Wake the listening processes */
        parent->sk_data_ready(parent);

        /* Send CC */
        nfc_llcp_send_cc(new_sock);

        release_sock(&sock->sk);
        sock_put(&sock->sk);

        return;

fail:
        /* Send DM */
        nfc_llcp_send_dm(local, dsap, ssap, reason);
}

int nfc_llcp_queue_i_frames(struct nfc_llcp_sock *sock)
{
        int nr_frames = 0;
        struct nfc_llcp_local *local = sock->local;

        pr_debug("Remote ready %d tx queue len %d remote rw %d",
                 sock->remote_ready, skb_queue_len(&sock->tx_pending_queue),
                 sock->remote_rw);

        /* Try to queue some I frames for transmission */
        while (sock->remote_ready &&
               skb_queue_len(&sock->tx_pending_queue) < sock->remote_rw) {
                struct sk_buff *pdu;

                pdu = skb_dequeue(&sock->tx_queue);
                if (pdu == NULL)
                        break;

                /* Update N(S)/N(R) */
                nfc_llcp_set_nrns(sock, pdu);

                skb_queue_tail(&local->tx_queue, pdu);
                nr_frames++;
        }

        return nr_frames;
}

static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local,
                               struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        struct sock *sk;
        u8 dsap, ssap, ptype, ns, nr;

        ptype = nfc_llcp_ptype(skb);
        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);
        ns = nfc_llcp_ns(skb);
        nr = nfc_llcp_nr(skb);

        pr_debug("%d %d R %d S %d\n", dsap, ssap, nr, ns);

        llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
        if (llcp_sock == NULL) {
                nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
                return;
        }

        sk = &llcp_sock->sk;
        lock_sock(sk);
        if (sk->sk_state == LLCP_CLOSED) {
                release_sock(sk);
                nfc_llcp_sock_put(llcp_sock);
        }

        /* Pass the payload upstream */
        if (ptype == LLCP_PDU_I) {
                pr_debug("I frame, queueing on %p\n", &llcp_sock->sk);

                if (ns == llcp_sock->recv_n)
                        llcp_sock->recv_n = (llcp_sock->recv_n + 1) % 16;
                else
                        pr_err("Received out of sequence I PDU\n");

                skb_pull(skb, LLCP_HEADER_SIZE + LLCP_SEQUENCE_SIZE);
                if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
                        /*
                         * I frames will be freed from the socket layer, so we
                         * need to keep them alive until someone receives them.
                         */
                        skb_get(skb);
                } else {
                        pr_err("Receive queue is full\n");
                }
        }

        /* Remove skbs from the pending queue */
        if (llcp_sock->send_ack_n != nr) {
                struct sk_buff *s, *tmp;
                u8 n;

                llcp_sock->send_ack_n = nr;

                /* Remove and free all skbs until ns == nr */
                skb_queue_walk_safe(&llcp_sock->tx_pending_queue, s, tmp) {
                        n = nfc_llcp_ns(s);

                        skb_unlink(s, &llcp_sock->tx_pending_queue);
                        kfree_skb(s);

                        if (n == nr)
                                break;
                }

                /* Re-queue the remaining skbs for transmission */
                skb_queue_reverse_walk_safe(&llcp_sock->tx_pending_queue,
                                            s, tmp) {
                        skb_unlink(s, &llcp_sock->tx_pending_queue);
                        skb_queue_head(&local->tx_queue, s);
                }
        }

        if (ptype == LLCP_PDU_RR)
                llcp_sock->remote_ready = true;
        else if (ptype == LLCP_PDU_RNR)
                llcp_sock->remote_ready = false;

        if (nfc_llcp_queue_i_frames(llcp_sock) == 0 && ptype == LLCP_PDU_I)
                nfc_llcp_send_rr(llcp_sock);

        release_sock(sk);
        nfc_llcp_sock_put(llcp_sock);
}

static void nfc_llcp_recv_disc(struct nfc_llcp_local *local,
                               const struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        struct sock *sk;
        u8 dsap, ssap;

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        if ((dsap == 0) && (ssap == 0)) {
                pr_debug("Connection termination");
                nfc_dep_link_down(local->dev);
                return;
        }

        llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
        if (llcp_sock == NULL) {
                nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
                return;
        }

        sk = &llcp_sock->sk;
        lock_sock(sk);

        nfc_llcp_socket_purge(llcp_sock);

        if (sk->sk_state == LLCP_CLOSED) {
                release_sock(sk);
                nfc_llcp_sock_put(llcp_sock);
        }

        if (sk->sk_state == LLCP_CONNECTED) {
                nfc_put_device(local->dev);
                sk->sk_state = LLCP_CLOSED;
                sk->sk_state_change(sk);
        }

        nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_DISC);

        release_sock(sk);
        nfc_llcp_sock_put(llcp_sock);
}

static void nfc_llcp_recv_cc(struct nfc_llcp_local *local,
                             const struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        struct sock *sk;
        u8 dsap, ssap;

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
        if (llcp_sock == NULL) {
                pr_err("Invalid CC\n");
                nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);

                return;
        }

        sk = &llcp_sock->sk;

        /* Unlink from connecting and link to the client array */
        nfc_llcp_sock_unlink(&local->connecting_sockets, sk);
        nfc_llcp_sock_link(&local->sockets, sk);
        llcp_sock->dsap = ssap;

        nfc_llcp_parse_connection_tlv(llcp_sock, &skb->data[LLCP_HEADER_SIZE],
                                      skb->len - LLCP_HEADER_SIZE);

        sk->sk_state = LLCP_CONNECTED;
        sk->sk_state_change(sk);

        nfc_llcp_sock_put(llcp_sock);
}

static void nfc_llcp_recv_dm(struct nfc_llcp_local *local,
                             const struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        struct sock *sk;
        u8 dsap, ssap, reason;

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);
        reason = skb->data[2];

        pr_debug("%d %d reason %d\n", ssap, dsap, reason);

        switch (reason) {
        case LLCP_DM_NOBOUND:
        case LLCP_DM_REJ:
                llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
                break;

        default:
                llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
                break;
        }

        if (llcp_sock == NULL) {
                pr_debug("Already closed\n");
                return;
        }

        sk = &llcp_sock->sk;

        sk->sk_err = ENXIO;
        sk->sk_state = LLCP_CLOSED;
        sk->sk_state_change(sk);

        nfc_llcp_sock_put(llcp_sock);
}

static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
                              const struct sk_buff *skb)
{
        struct nfc_llcp_sock *llcp_sock;
        u8 dsap, ssap, type, length, tid, sap;
        const u8 *tlv;
        u16 tlv_len, offset;
        const char *service_name;
        size_t service_name_len;
        struct nfc_llcp_sdp_tlv *sdp;
        HLIST_HEAD(llc_sdres_list);
        size_t sdres_tlvs_len;
        HLIST_HEAD(nl_sdres_list);

        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        pr_debug("%d %d\n", dsap, ssap);

        if (dsap != LLCP_SAP_SDP || ssap != LLCP_SAP_SDP) {
                pr_err("Wrong SNL SAP\n");
                return;
        }

        tlv = &skb->data[LLCP_HEADER_SIZE];
        tlv_len = skb->len - LLCP_HEADER_SIZE;
        offset = 0;
        sdres_tlvs_len = 0;

        while (offset < tlv_len) {
                type = tlv[0];
                length = tlv[1];

                switch (type) {
                case LLCP_TLV_SDREQ:
                        tid = tlv[2];
                        service_name = (char *) &tlv[3];
                        service_name_len = length - 1;

                        pr_debug("Looking for %.16s\n", service_name);

                        if (service_name_len == strlen("urn:nfc:sn:sdp") &&
                            !strncmp(service_name, "urn:nfc:sn:sdp",
                                     service_name_len)) {
                                sap = 1;
                                goto add_snl;
                        }

                        llcp_sock = nfc_llcp_sock_from_sn(local, service_name,
                                                          service_name_len,
                                                          true);
                        if (!llcp_sock) {
                                sap = 0;
                                goto add_snl;
                        }

                        /*
                         * We found a socket but its ssap has not been reserved
                         * yet. We need to assign it for good and send a reply.
                         * The ssap will be freed when the socket is closed.
                         */
                        if (llcp_sock->ssap == LLCP_SDP_UNBOUND) {
                                atomic_t *client_count;

                                sap = nfc_llcp_reserve_sdp_ssap(local);

                                pr_debug("Reserving %d\n", sap);

                                if (sap == LLCP_SAP_MAX) {
                                        sap = 0;
                                        nfc_llcp_sock_put(llcp_sock);
                                        goto add_snl;
                                }

                                client_count =
                                        &local->local_sdp_cnt[sap -
                                                              LLCP_WKS_NUM_SAP];

                                atomic_inc(client_count);

                                llcp_sock->ssap = sap;
                                llcp_sock->reserved_ssap = sap;
                        } else {
                                sap = llcp_sock->ssap;
                        }

                        pr_debug("%p %d\n", llcp_sock, sap);

                        nfc_llcp_sock_put(llcp_sock);
add_snl:
                        sdp = nfc_llcp_build_sdres_tlv(tid, sap);
                        if (sdp == NULL)
                                goto exit;

                        sdres_tlvs_len += sdp->tlv_len;
                        hlist_add_head(&sdp->node, &llc_sdres_list);
                        break;

                case LLCP_TLV_SDRES:
                        mutex_lock(&local->sdreq_lock);

                        pr_debug("LLCP_TLV_SDRES: searching tid %d\n", tlv[2]);

                        hlist_for_each_entry(sdp, &local->pending_sdreqs, node) {
                                if (sdp->tid != tlv[2])
                                        continue;

                                sdp->sap = tlv[3];

                                pr_debug("Found: uri=%s, sap=%d\n",
                                         sdp->uri, sdp->sap);

                                hlist_del(&sdp->node);

                                hlist_add_head(&sdp->node, &nl_sdres_list);

                                break;
                        }

                        mutex_unlock(&local->sdreq_lock);
                        break;

                default:
                        pr_err("Invalid SNL tlv value 0x%x\n", type);
                        break;
                }

                offset += length + 2;
                tlv += length + 2;
        }

exit:
        if (!hlist_empty(&nl_sdres_list))
                nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);

        if (!hlist_empty(&llc_sdres_list))
                nfc_llcp_send_snl_sdres(local, &llc_sdres_list, sdres_tlvs_len);
}

static void nfc_llcp_recv_agf(struct nfc_llcp_local *local, struct sk_buff *skb)
{
        u8 ptype;
        u16 pdu_len;
        struct sk_buff *new_skb;

        if (skb->len <= LLCP_HEADER_SIZE) {
                pr_err("Malformed AGF PDU\n");
                return;
        }

        skb_pull(skb, LLCP_HEADER_SIZE);

        while (skb->len > LLCP_AGF_PDU_HEADER_SIZE) {
                pdu_len = skb->data[0] << 8 | skb->data[1];

                skb_pull(skb, LLCP_AGF_PDU_HEADER_SIZE);

                if (pdu_len < LLCP_HEADER_SIZE || pdu_len > skb->len) {
                        pr_err("Malformed AGF PDU\n");
                        return;
                }

                ptype = nfc_llcp_ptype(skb);

                if (ptype == LLCP_PDU_SYMM || ptype == LLCP_PDU_AGF)
                        goto next;

                new_skb = nfc_alloc_recv_skb(pdu_len, GFP_KERNEL);
                if (new_skb == NULL) {
                        pr_err("Could not allocate PDU\n");
                        return;
                }

                skb_put_data(new_skb, skb->data, pdu_len);

                nfc_llcp_rx_skb(local, new_skb);

                kfree_skb(new_skb);
next:
                skb_pull(skb, pdu_len);
        }
}

static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb)
{
        u8 dsap, ssap, ptype;

        ptype = nfc_llcp_ptype(skb);
        dsap = nfc_llcp_dsap(skb);
        ssap = nfc_llcp_ssap(skb);

        pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);

        if (ptype != LLCP_PDU_SYMM)
                print_hex_dump_debug("LLCP Rx: ", DUMP_PREFIX_OFFSET, 16, 1,
                                     skb->data, skb->len, true);

        switch (ptype) {
        case LLCP_PDU_SYMM:
                pr_debug("SYMM\n");
                break;

        case LLCP_PDU_UI:
                pr_debug("UI\n");
                nfc_llcp_recv_ui(local, skb);
                break;

        case LLCP_PDU_CONNECT:
                pr_debug("CONNECT\n");
                nfc_llcp_recv_connect(local, skb);
                break;

        case LLCP_PDU_DISC:
                pr_debug("DISC\n");
                nfc_llcp_recv_disc(local, skb);
                break;

        case LLCP_PDU_CC:
                pr_debug("CC\n");
                nfc_llcp_recv_cc(local, skb);
                break;

        case LLCP_PDU_DM:
                pr_debug("DM\n");
                nfc_llcp_recv_dm(local, skb);
                break;

        case LLCP_PDU_SNL:
                pr_debug("SNL\n");
                nfc_llcp_recv_snl(local, skb);
                break;

        case LLCP_PDU_I:
        case LLCP_PDU_RR:
        case LLCP_PDU_RNR:
                pr_debug("I frame\n");
                nfc_llcp_recv_hdlc(local, skb);
                break;

        case LLCP_PDU_AGF:
                pr_debug("AGF frame\n");
                nfc_llcp_recv_agf(local, skb);
                break;
        }
}

static void nfc_llcp_rx_work(struct work_struct *work)
{
        struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
                                                    rx_work);
        struct sk_buff *skb;

        skb = local->rx_pending;
        if (skb == NULL) {
                pr_debug("No pending SKB\n");
                return;
        }

        __net_timestamp(skb);

        nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_RX);

        nfc_llcp_rx_skb(local, skb);

        schedule_work(&local->tx_work);
        kfree_skb(local->rx_pending);
        local->rx_pending = NULL;
}

static void __nfc_llcp_recv(struct nfc_llcp_local *local, struct sk_buff *skb)
{
        local->rx_pending = skb;
        timer_delete(&local->link_timer);
        schedule_work(&local->rx_work);
}

void nfc_llcp_recv(void *data, struct sk_buff *skb, int err)
{
        struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;

        if (err < 0) {
                pr_err("LLCP PDU receive err %d\n", err);
                return;
        }

        __nfc_llcp_recv(local, skb);
}

int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb)
{
        struct nfc_llcp_local *local;

        local = nfc_llcp_find_local(dev);
        if (local == NULL) {
                kfree_skb(skb);
                return -ENODEV;
        }

        __nfc_llcp_recv(local, skb);

        nfc_llcp_local_put(local);

        return 0;
}

void nfc_llcp_mac_is_down(struct nfc_dev *dev)
{
        struct nfc_llcp_local *local;

        local = nfc_llcp_find_local(dev);
        if (local == NULL)
                return;

        local->remote_miu = LLCP_DEFAULT_MIU;
        local->remote_lto = LLCP_DEFAULT_LTO;

        /* Close and purge all existing sockets */
        nfc_llcp_socket_release(local, true, 0);

        nfc_llcp_local_put(local);
}

void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx,
                        u8 comm_mode, u8 rf_mode)
{
        struct nfc_llcp_local *local;

        pr_debug("rf mode %d\n", rf_mode);

        local = nfc_llcp_find_local(dev);
        if (local == NULL)
                return;

        local->target_idx = target_idx;
        local->comm_mode = comm_mode;
        local->rf_mode = rf_mode;

        if (rf_mode == NFC_RF_INITIATOR) {
                pr_debug("Queueing Tx work\n");

                schedule_work(&local->tx_work);
        } else {
                mod_timer(&local->link_timer,
                          jiffies + msecs_to_jiffies(local->remote_lto));
        }

        nfc_llcp_local_put(local);
}

int nfc_llcp_register_device(struct nfc_dev *ndev)
{
        struct nfc_llcp_local *local;

        local = kzalloc_obj(struct nfc_llcp_local);
        if (local == NULL)
                return -ENOMEM;

        /* As we are going to initialize local's refcount, we need to get the
         * nfc_dev to avoid UAF, otherwise there is no point in continuing.
         * See nfc_llcp_local_get().
         */
        local->dev = nfc_get_device(ndev->idx);
        if (!local->dev) {
                kfree(local);
                return -ENODEV;
        }

        INIT_LIST_HEAD(&local->list);
        kref_init(&local->ref);
        mutex_init(&local->sdp_lock);
        timer_setup(&local->link_timer, nfc_llcp_symm_timer, 0);

        skb_queue_head_init(&local->tx_queue);
        INIT_WORK(&local->tx_work, nfc_llcp_tx_work);

        local->rx_pending = NULL;
        INIT_WORK(&local->rx_work, nfc_llcp_rx_work);

        INIT_WORK(&local->timeout_work, nfc_llcp_timeout_work);

        rwlock_init(&local->sockets.lock);
        rwlock_init(&local->connecting_sockets.lock);
        rwlock_init(&local->raw_sockets.lock);

        local->lto = 150; /* 1500 ms */
        local->rw = LLCP_MAX_RW;
        local->miux = cpu_to_be16(LLCP_MAX_MIUX);
        local->local_wks = 0x1; /* LLC Link Management */

        nfc_llcp_build_gb(local);

        local->remote_miu = LLCP_DEFAULT_MIU;
        local->remote_lto = LLCP_DEFAULT_LTO;

        mutex_init(&local->sdreq_lock);
        INIT_HLIST_HEAD(&local->pending_sdreqs);
        timer_setup(&local->sdreq_timer, nfc_llcp_sdreq_timer, 0);
        INIT_WORK(&local->sdreq_timeout_work, nfc_llcp_sdreq_timeout_work);

        spin_lock(&llcp_devices_lock);
        list_add(&local->list, &llcp_devices);
        spin_unlock(&llcp_devices_lock);

        return 0;
}

void nfc_llcp_unregister_device(struct nfc_dev *dev)
{
        struct nfc_llcp_local *local = nfc_llcp_remove_local(dev);

        if (local == NULL) {
                pr_debug("No such device\n");
                return;
        }

        local_cleanup(local);

        nfc_llcp_local_put(local);
}

int __init nfc_llcp_init(void)
{
        return nfc_llcp_sock_init();
}

void nfc_llcp_exit(void)
{
        nfc_llcp_sock_exit();
}