// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2011  Intel Corporation. All rights reserved.
 */

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

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

#include <net/nfc/nfc.h>

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

static const u8 llcp_tlv_length[LLCP_TLV_MAX] = {
        0,
        1, /* VERSION */
        2, /* MIUX */
        2, /* WKS */
        1, /* LTO */
        1, /* RW */
        0, /* SN */
        1, /* OPT */
        0, /* SDREQ */
        2, /* SDRES */

};

static u8 llcp_tlv8(const u8 *tlv, u8 type)
{
        if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
                return 0;

        return tlv[2];
}

static u16 llcp_tlv16(const u8 *tlv, u8 type)
{
        if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
                return 0;

        return be16_to_cpu(*((__be16 *)(tlv + 2)));
}


static u8 llcp_tlv_version(const u8 *tlv)
{
        return llcp_tlv8(tlv, LLCP_TLV_VERSION);
}

static u16 llcp_tlv_miux(const u8 *tlv)
{
        return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7ff;
}

static u16 llcp_tlv_wks(const u8 *tlv)
{
        return llcp_tlv16(tlv, LLCP_TLV_WKS);
}

static u16 llcp_tlv_lto(const u8 *tlv)
{
        return llcp_tlv8(tlv, LLCP_TLV_LTO);
}

static u8 llcp_tlv_opt(const u8 *tlv)
{
        return llcp_tlv8(tlv, LLCP_TLV_OPT);
}

static u8 llcp_tlv_rw(const u8 *tlv)
{
        return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
}

u8 *nfc_llcp_build_tlv(u8 type, const u8 *value, u8 value_length, u8 *tlv_length)
{
        u8 *tlv, length;

        pr_debug("type %d\n", type);

        if (type >= LLCP_TLV_MAX)
                return NULL;

        length = llcp_tlv_length[type];
        if (length == 0 && value_length == 0)
                return NULL;
        else if (length == 0)
                length = value_length;

        *tlv_length = 2 + length;
        tlv = kzalloc(2 + length, GFP_KERNEL);
        if (tlv == NULL)
                return tlv;

        tlv[0] = type;
        tlv[1] = length;
        memcpy(tlv + 2, value, length);

        return tlv;
}

struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap)
{
        struct nfc_llcp_sdp_tlv *sdres;
        u8 value[2];

        sdres = kzalloc_obj(struct nfc_llcp_sdp_tlv);
        if (sdres == NULL)
                return NULL;

        value[0] = tid;
        value[1] = sap;

        sdres->tlv = nfc_llcp_build_tlv(LLCP_TLV_SDRES, value, 2,
                                        &sdres->tlv_len);
        if (sdres->tlv == NULL) {
                kfree(sdres);
                return NULL;
        }

        sdres->tid = tid;
        sdres->sap = sap;

        INIT_HLIST_NODE(&sdres->node);

        return sdres;
}

struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, const char *uri,
                                                  size_t uri_len)
{
        struct nfc_llcp_sdp_tlv *sdreq;

        pr_debug("uri: %s, len: %zu\n", uri, uri_len);

        /* sdreq->tlv_len is u8, takes uri_len, + 3 for header, + 1 for NULL */
        if (WARN_ON_ONCE(uri_len > U8_MAX - 4))
                return NULL;

        sdreq = kzalloc_obj(struct nfc_llcp_sdp_tlv);
        if (sdreq == NULL)
                return NULL;

        sdreq->tlv_len = uri_len + 3;

        if (uri[uri_len - 1] == 0)
                sdreq->tlv_len--;

        sdreq->tlv = kzalloc(sdreq->tlv_len + 1, GFP_KERNEL);
        if (sdreq->tlv == NULL) {
                kfree(sdreq);
                return NULL;
        }

        sdreq->tlv[0] = LLCP_TLV_SDREQ;
        sdreq->tlv[1] = sdreq->tlv_len - 2;
        sdreq->tlv[2] = tid;

        sdreq->tid = tid;
        sdreq->uri = sdreq->tlv + 3;
        memcpy(sdreq->uri, uri, uri_len);

        sdreq->time = jiffies;

        INIT_HLIST_NODE(&sdreq->node);

        return sdreq;
}

void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp)
{
        kfree(sdp->tlv);
        kfree(sdp);
}

void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head)
{
        struct nfc_llcp_sdp_tlv *sdp;
        struct hlist_node *n;

        hlist_for_each_entry_safe(sdp, n, head, node) {
                hlist_del(&sdp->node);

                nfc_llcp_free_sdp_tlv(sdp);
        }
}

int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
                          const u8 *tlv_array, u16 tlv_array_len)
{
        const u8 *tlv = tlv_array;
        u8 type, length, offset = 0;

        pr_debug("TLV array length %d\n", tlv_array_len);

        if (local == NULL)
                return -ENODEV;

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

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

                switch (type) {
                case LLCP_TLV_VERSION:
                        local->remote_version = llcp_tlv_version(tlv);
                        break;
                case LLCP_TLV_MIUX:
                        local->remote_miu = llcp_tlv_miux(tlv) + 128;
                        break;
                case LLCP_TLV_WKS:
                        local->remote_wks = llcp_tlv_wks(tlv);
                        break;
                case LLCP_TLV_LTO:
                        local->remote_lto = llcp_tlv_lto(tlv) * 10;
                        break;
                case LLCP_TLV_OPT:
                        local->remote_opt = llcp_tlv_opt(tlv);
                        break;
                default:
                        pr_err("Invalid gt tlv value 0x%x\n", type);
                        break;
                }

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

        pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x\n",
                 local->remote_version, local->remote_miu,
                 local->remote_lto, local->remote_opt,
                 local->remote_wks);

        return 0;
}

int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
                                  const u8 *tlv_array, u16 tlv_array_len)
{
        const u8 *tlv = tlv_array;
        u8 type, length, offset = 0;

        pr_debug("TLV array length %d\n", tlv_array_len);

        if (sock == NULL)
                return -ENOTCONN;

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

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

                switch (type) {
                case LLCP_TLV_MIUX:
                        sock->remote_miu = llcp_tlv_miux(tlv) + 128;
                        break;
                case LLCP_TLV_RW:
                        sock->remote_rw = llcp_tlv_rw(tlv);
                        break;
                case LLCP_TLV_SN:
                        break;
                default:
                        pr_err("Invalid gt tlv value 0x%x\n", type);
                        break;
                }

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

        pr_debug("sock %p rw %d miu %d\n", sock,
                 sock->remote_rw, sock->remote_miu);

        return 0;
}

static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
                                       u8 dsap, u8 ssap, u8 ptype)
{
        u8 header[2];

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

        header[0] = (u8)((dsap << 2) | (ptype >> 2));
        header[1] = (u8)((ptype << 6) | ssap);

        pr_debug("header 0x%x 0x%x\n", header[0], header[1]);

        skb_put_data(pdu, header, LLCP_HEADER_SIZE);

        return pdu;
}

static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, const u8 *tlv,
                                    u8 tlv_length)
{
        /* XXX Add an skb length check */

        if (tlv == NULL)
                return NULL;

        skb_put_data(pdu, tlv, tlv_length);

        return pdu;
}

static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
                                         u8 cmd, u16 size)
{
        struct sk_buff *skb;
        int err;

        if (sock->ssap == 0)
                return NULL;

        skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
                                 size + LLCP_HEADER_SIZE, &err);
        if (skb == NULL) {
                pr_err("Could not allocate PDU\n");
                return NULL;
        }

        skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);

        return skb;
}

int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
{
        struct sk_buff *skb;
        struct nfc_dev *dev;
        struct nfc_llcp_local *local;

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        dev = sock->dev;
        if (dev == NULL)
                return -ENODEV;

        skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
        if (skb == NULL)
                return -ENOMEM;

        skb_queue_tail(&local->tx_queue, skb);

        return 0;
}

int nfc_llcp_send_symm(struct nfc_dev *dev)
{
        struct sk_buff *skb;
        struct nfc_llcp_local *local;
        u16 size = 0;
        int err;

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

        size += LLCP_HEADER_SIZE;
        size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;

        skb = alloc_skb(size, GFP_KERNEL);
        if (skb == NULL) {
                err = -ENOMEM;
                goto out;
        }

        skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);

        skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);

        __net_timestamp(skb);

        nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_TX);

        err = nfc_data_exchange(dev, local->target_idx, skb,
                                 nfc_llcp_recv, local);
out:
        nfc_llcp_local_put(local);
        return err;
}

int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
{
        struct nfc_llcp_local *local;
        struct sk_buff *skb;
        const u8 *service_name_tlv = NULL;
        const u8 *miux_tlv = NULL;
        const u8 *rw_tlv = NULL;
        u8 service_name_tlv_length = 0;
        u8 miux_tlv_length,  rw_tlv_length, rw;
        int err;
        u16 size = 0;
        __be16 miux;

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        if (sock->service_name != NULL) {
                service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
                                                      sock->service_name,
                                                      sock->service_name_len,
                                                      &service_name_tlv_length);
                if (!service_name_tlv) {
                        err = -ENOMEM;
                        goto error_tlv;
                }
                size += service_name_tlv_length;
        }

        /* If the socket parameters are not set, use the local ones */
        miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
                local->miux : sock->miux;
        rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;

        miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
                                      &miux_tlv_length);
        if (!miux_tlv) {
                err = -ENOMEM;
                goto error_tlv;
        }
        size += miux_tlv_length;

        rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
        if (!rw_tlv) {
                err = -ENOMEM;
                goto error_tlv;
        }
        size += rw_tlv_length;

        pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);

        skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
        if (skb == NULL) {
                err = -ENOMEM;
                goto error_tlv;
        }

        llcp_add_tlv(skb, service_name_tlv, service_name_tlv_length);
        llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
        llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

        skb_queue_tail(&local->tx_queue, skb);

        err = 0;

error_tlv:
        if (err)
                pr_err("error %d\n", err);

        kfree(service_name_tlv);
        kfree(miux_tlv);
        kfree(rw_tlv);

        return err;
}

int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
{
        struct nfc_llcp_local *local;
        struct sk_buff *skb;
        const u8 *miux_tlv = NULL;
        const u8 *rw_tlv = NULL;
        u8 miux_tlv_length, rw_tlv_length, rw;
        int err;
        u16 size = 0;
        __be16 miux;

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        /* If the socket parameters are not set, use the local ones */
        miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
                local->miux : sock->miux;
        rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;

        miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
                                      &miux_tlv_length);
        if (!miux_tlv) {
                err = -ENOMEM;
                goto error_tlv;
        }
        size += miux_tlv_length;

        rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
        if (!rw_tlv) {
                err = -ENOMEM;
                goto error_tlv;
        }
        size += rw_tlv_length;

        skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
        if (skb == NULL) {
                err = -ENOMEM;
                goto error_tlv;
        }

        llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
        llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

        skb_queue_tail(&local->tx_queue, skb);

        err = 0;

error_tlv:
        if (err)
                pr_err("error %d\n", err);

        kfree(miux_tlv);
        kfree(rw_tlv);

        return err;
}

static struct sk_buff *nfc_llcp_allocate_snl(struct nfc_llcp_local *local,
                                             size_t tlv_length)
{
        struct sk_buff *skb;
        struct nfc_dev *dev;
        u16 size = 0;

        if (local == NULL)
                return ERR_PTR(-ENODEV);

        dev = local->dev;
        if (dev == NULL)
                return ERR_PTR(-ENODEV);

        size += LLCP_HEADER_SIZE;
        size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
        size += tlv_length;

        skb = alloc_skb(size, GFP_KERNEL);
        if (skb == NULL)
                return ERR_PTR(-ENOMEM);

        skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);

        skb = llcp_add_header(skb, LLCP_SAP_SDP, LLCP_SAP_SDP, LLCP_PDU_SNL);

        return skb;
}

int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
                            struct hlist_head *tlv_list, size_t tlvs_len)
{
        struct nfc_llcp_sdp_tlv *sdp;
        struct hlist_node *n;
        struct sk_buff *skb;

        skb = nfc_llcp_allocate_snl(local, tlvs_len);
        if (IS_ERR(skb))
                return PTR_ERR(skb);

        hlist_for_each_entry_safe(sdp, n, tlv_list, node) {
                skb_put_data(skb, sdp->tlv, sdp->tlv_len);

                hlist_del(&sdp->node);

                nfc_llcp_free_sdp_tlv(sdp);
        }

        skb_queue_tail(&local->tx_queue, skb);

        return 0;
}

int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
                            struct hlist_head *tlv_list, size_t tlvs_len)
{
        struct nfc_llcp_sdp_tlv *sdreq;
        struct hlist_node *n;
        struct sk_buff *skb;

        skb = nfc_llcp_allocate_snl(local, tlvs_len);
        if (IS_ERR(skb))
                return PTR_ERR(skb);

        mutex_lock(&local->sdreq_lock);

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

        hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
                pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);

                skb_put_data(skb, sdreq->tlv, sdreq->tlv_len);

                hlist_del(&sdreq->node);

                hlist_add_head(&sdreq->node, &local->pending_sdreqs);
        }

        mutex_unlock(&local->sdreq_lock);

        skb_queue_tail(&local->tx_queue, skb);

        return 0;
}

int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
{
        struct sk_buff *skb;
        struct nfc_dev *dev;
        u16 size = 1; /* Reason code */

        pr_debug("Sending DM reason 0x%x\n", reason);

        if (local == NULL)
                return -ENODEV;

        dev = local->dev;
        if (dev == NULL)
                return -ENODEV;

        size += LLCP_HEADER_SIZE;
        size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;

        skb = alloc_skb(size, GFP_KERNEL);
        if (skb == NULL)
                return -ENOMEM;

        skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);

        skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);

        skb_put_data(skb, &reason, 1);

        skb_queue_head(&local->tx_queue, skb);

        return 0;
}

int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
                          struct msghdr *msg, size_t len)
{
        struct sk_buff *pdu;
        struct sock *sk = &sock->sk;
        struct nfc_llcp_local *local;
        size_t frag_len = 0, remaining_len;
        u8 *msg_data, *msg_ptr;
        u16 remote_miu;

        pr_debug("Send I frame len %zd\n", len);

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        /* Remote is ready but has not acknowledged our frames */
        if((sock->remote_ready &&
            skb_queue_len(&sock->tx_pending_queue) >= sock->remote_rw &&
            skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
                pr_err("Pending queue is full %d frames\n",
                       skb_queue_len(&sock->tx_pending_queue));
                return -ENOBUFS;
        }

        /* Remote is not ready and we've been queueing enough frames */
        if ((!sock->remote_ready &&
             skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
                pr_err("Tx queue is full %d frames\n",
                       skb_queue_len(&sock->tx_queue));
                return -ENOBUFS;
        }

        msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
        if (msg_data == NULL)
                return -ENOMEM;

        if (memcpy_from_msg(msg_data, msg, len)) {
                kfree(msg_data);
                return -EFAULT;
        }

        remaining_len = len;
        msg_ptr = msg_data;

        do {
                remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
                                LLCP_DEFAULT_MIU : sock->remote_miu;

                frag_len = min_t(size_t, remote_miu, remaining_len);

                pr_debug("Fragment %zd bytes remaining %zd",
                         frag_len, remaining_len);

                pdu = llcp_allocate_pdu(sock, LLCP_PDU_I,
                                        frag_len + LLCP_SEQUENCE_SIZE);
                if (pdu == NULL) {
                        kfree(msg_data);
                        return -ENOMEM;
                }

                skb_put(pdu, LLCP_SEQUENCE_SIZE);

                if (likely(frag_len > 0))
                        skb_put_data(pdu, msg_ptr, frag_len);

                skb_queue_tail(&sock->tx_queue, pdu);

                lock_sock(sk);

                nfc_llcp_queue_i_frames(sock);

                release_sock(sk);

                remaining_len -= frag_len;
                msg_ptr += frag_len;
        } while (remaining_len > 0);

        kfree(msg_data);

        return len;
}

int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
                           struct msghdr *msg, size_t len)
{
        struct sk_buff *pdu;
        struct nfc_llcp_local *local;
        size_t frag_len = 0, remaining_len;
        u8 *msg_ptr, *msg_data;
        u16 remote_miu;
        int err;

        pr_debug("Send UI frame len %zd\n", len);

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
        if (msg_data == NULL)
                return -ENOMEM;

        if (memcpy_from_msg(msg_data, msg, len)) {
                kfree(msg_data);
                return -EFAULT;
        }

        remaining_len = len;
        msg_ptr = msg_data;

        do {
                remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
                                local->remote_miu : sock->remote_miu;

                frag_len = min_t(size_t, remote_miu, remaining_len);

                pr_debug("Fragment %zd bytes remaining %zd",
                         frag_len, remaining_len);

                pdu = nfc_alloc_send_skb(sock->dev, &sock->sk, 0,
                                         frag_len + LLCP_HEADER_SIZE, &err);
                if (pdu == NULL) {
                        pr_err("Could not allocate PDU (error=%d)\n", err);
                        len -= remaining_len;
                        if (len == 0)
                                len = err;
                        break;
                }

                pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);

                if (likely(frag_len > 0))
                        skb_put_data(pdu, msg_ptr, frag_len);

                spin_lock(&local->tx_queue.lock);

                if (list_empty(&local->list)) {
                        spin_unlock(&local->tx_queue.lock);

                        kfree_skb(pdu);

                        len -= remaining_len;
                        if (len == 0)
                                len = -ENXIO;
                        break;
                }

                /* No need to check for the peer RW for UI frames */
                __skb_queue_tail(&local->tx_queue, pdu);

                spin_unlock(&local->tx_queue.lock);

                remaining_len -= frag_len;
                msg_ptr += frag_len;
        } while (remaining_len > 0);

        kfree(msg_data);

        return len;
}

int nfc_llcp_send_rr(struct nfc_llcp_sock *sock)
{
        struct sk_buff *skb;
        struct nfc_llcp_local *local;

        pr_debug("Send rr nr %d\n", sock->recv_n);

        local = sock->local;
        if (local == NULL)
                return -ENODEV;

        skb = llcp_allocate_pdu(sock, LLCP_PDU_RR, LLCP_SEQUENCE_SIZE);
        if (skb == NULL)
                return -ENOMEM;

        skb_put(skb, LLCP_SEQUENCE_SIZE);

        skb->data[2] = sock->recv_n;

        skb_queue_head(&local->tx_queue, skb);

        return 0;
}