commands.c

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/*
 * Copyright (C) 2011  Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

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

    return tlv[2];
}

static u16 llcp_tlv16(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(u8 *tlv)
{
    return llcp_tlv8(tlv, LLCP_TLV_VERSION);
}

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

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

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

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

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

u8 *nfc_llcp_build_tlv(u8 type, 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;
}

int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
              u8 *tlv_array, u16 tlv_array_len)
{
    u8 *tlv = tlv_array, 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,
                  u8 *tlv_array, u16 tlv_array_len)
{
    u8 *tlv = tlv_array, 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->miu = llcp_tlv_miux(tlv) + 128;
            break;
        case LLCP_TLV_RW:
            sock->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->rw, sock->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]);

    memcpy(skb_put(pdu, LLCP_HEADER_SIZE), header, LLCP_HEADER_SIZE);

    return pdu;
}

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

    if (tlv == NULL)
        return NULL;

    memcpy(skb_put(pdu, tlv_length), 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_disconnect(struct nfc_llcp_sock *sock)
{
    struct sk_buff *skb;
    struct nfc_dev *dev;
    struct nfc_llcp_local *local;
    u16 size = 0;

    pr_debug("Sending DISC\n");

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

    dev = sock->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_ATOMIC);
    if (skb == NULL)
        return -ENOMEM;

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

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

    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;

    pr_debug("Sending SYMM\n");

    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)
        return -ENOMEM;

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

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

    nfc_llcp_send_to_raw_sock(local, skb, NFC_LLCP_DIRECTION_TX);

    return nfc_data_exchange(dev, local->target_idx, skb,
                 nfc_llcp_recv, local);
}

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

    pr_debug("Sending CONNECT\n");

    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);
        size += service_name_tlv_length;
    }

    miux = cpu_to_be16(LLCP_MAX_MIUX);
    miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
                      &miux_tlv_length);
    size += miux_tlv_length;

    rw = LLCP_MAX_RW;
    rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
    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;
    }

    if (service_name_tlv != NULL)
        skb = llcp_add_tlv(skb, service_name_tlv,
                   service_name_tlv_length);

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

    skb_queue_tail(&local->tx_queue, skb);

    return 0;

error_tlv:
    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;
    u8 *miux_tlv = NULL, miux_tlv_length;
    u8 *rw_tlv = NULL, rw_tlv_length, rw;
    __be16 miux;
    int err;
    u16 size = 0;

    pr_debug("Sending CC\n");

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

    miux = cpu_to_be16(LLCP_MAX_MIUX);
    miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
                      &miux_tlv_length);
    size += miux_tlv_length;

    rw = LLCP_MAX_RW;
    rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
    size += rw_tlv_length;

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

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

    skb_queue_tail(&local->tx_queue, skb);

    return 0;

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

    kfree(miux_tlv);
    kfree(rw_tlv);

    return err;
}

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);

    memcpy(skb_put(skb, 1), &reason, 1);

    skb_queue_head(&local->tx_queue, skb);

    return 0;
}

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

    pr_debug("Send DISC\n");

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

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

    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;

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

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

    msg_data = kzalloc(len, GFP_KERNEL);
    if (msg_data == NULL)
        return -ENOMEM;

    if (memcpy_fromiovec(msg_data, msg->msg_iov, len)) {
        kfree(msg_data);
        return -EFAULT;
    }

    remaining_len = len;
    msg_ptr = msg_data;

    while (remaining_len > 0) {

        frag_len = min_t(size_t, sock->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)
            return -ENOMEM;

        skb_put(pdu, LLCP_SEQUENCE_SIZE);

        memcpy(skb_put(pdu, frag_len), 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;
    }

    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;
}