LXR linux/net/nfc/nci/data.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  The NFC Controller Interface is the communication protocol between an
   4 *  NFC Controller (NFCC) and a Device Host (DH).
   5 *
   6 *  Copyright (C) 2011 Texas Instruments, Inc.
   7 *  Copyright (C) 2014 Marvell International Ltd.
   8 *
   9 *  Written by Ilan Elias <ilane@ti.com>
  10 */
  11
  12#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
  13
  14#include <linux/types.h>
  15#include <linux/interrupt.h>
  16#include <linux/wait.h>
  17#include <linux/bitops.h>
  18#include <linux/skbuff.h>
  19
  20#include "../nfc.h"
  21#include <net/nfc/nci.h>
  22#include <net/nfc/nci_core.h>
  23#include <linux/nfc.h>
  24
  25/* Complete data exchange transaction and forward skb to nfc core */
  26void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
  27                                __u8 conn_id, int err)
  28{
  29        const struct nci_conn_info *conn_info;
  30        data_exchange_cb_t cb;
  31        void *cb_context;
  32
  33        conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
  34        if (!conn_info) {
  35                kfree_skb(skb);
  36                goto exit;
  37        }
  38
  39        cb = conn_info->data_exchange_cb;
  40        cb_context = conn_info->data_exchange_cb_context;
  41
  42        pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
  43
  44        /* data exchange is complete, stop the data timer */
  45        del_timer_sync(&ndev->data_timer);
  46        clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
  47
  48        if (cb) {
  49                /* forward skb to nfc core */
  50                cb(cb_context, skb, err);
  51        } else if (skb) {
  52                pr_err("no rx callback, dropping rx data...\n");
  53
  54                /* no waiting callback, free skb */
  55                kfree_skb(skb);
  56        }
  57
  58exit:
  59        clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
  60}
  61
  62/* ----------------- NCI TX Data ----------------- */
  63
  64static inline void nci_push_data_hdr(struct nci_dev *ndev,
  65                                     __u8 conn_id,
  66                                     struct sk_buff *skb,
  67                                     __u8 pbf)
  68{
  69        struct nci_data_hdr *hdr;
  70        int plen = skb->len;
  71
  72        hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
  73        hdr->conn_id = conn_id;
  74        hdr->rfu = 0;
  75        hdr->plen = plen;
  76
  77        nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
  78        nci_pbf_set((__u8 *)hdr, pbf);
  79}
  80
  81int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
  82{
  83        const struct nci_conn_info *conn_info;
  84
  85        conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
  86        if (!conn_info)
  87                return -EPROTO;
  88
  89        return conn_info->max_pkt_payload_len;
  90}
  91EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
  92
  93static int nci_queue_tx_data_frags(struct nci_dev *ndev,
  94                                   __u8 conn_id,
  95                                   struct sk_buff *skb) {
  96        const struct nci_conn_info *conn_info;
  97        int total_len = skb->len;
  98        const unsigned char *data = skb->data;
  99        unsigned long flags;
 100        struct sk_buff_head frags_q;
 101        struct sk_buff *skb_frag;
 102        int frag_len;
 103        int rc = 0;
 104
 105        pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
 106
 107        conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
 108        if (!conn_info) {
 109                rc = -EPROTO;
 110                goto exit;
 111        }
 112
 113        __skb_queue_head_init(&frags_q);
 114
 115        while (total_len) {
 116                frag_len =
 117                        min_t(int, total_len, conn_info->max_pkt_payload_len);
 118
 119                skb_frag = nci_skb_alloc(ndev,
 120                                         (NCI_DATA_HDR_SIZE + frag_len),
 121                                         GFP_KERNEL);
 122                if (skb_frag == NULL) {
 123                        rc = -ENOMEM;
 124                        goto free_exit;
 125                }
 126                skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
 127
 128                /* first, copy the data */
 129                skb_put_data(skb_frag, data, frag_len);
 130
 131                /* second, set the header */
 132                nci_push_data_hdr(ndev, conn_id, skb_frag,
 133                                  ((total_len == frag_len) ?
 134                                   (NCI_PBF_LAST) : (NCI_PBF_CONT)));
 135
 136                __skb_queue_tail(&frags_q, skb_frag);
 137
 138                data += frag_len;
 139                total_len -= frag_len;
 140
 141                pr_debug("frag_len %d, remaining total_len %d\n",
 142                         frag_len, total_len);
 143        }
 144
 145        /* queue all fragments atomically */
 146        spin_lock_irqsave(&ndev->tx_q.lock, flags);
 147
 148        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 149                __skb_queue_tail(&ndev->tx_q, skb_frag);
 150
 151        spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
 152
 153        /* free the original skb */
 154        kfree_skb(skb);
 155
 156        goto exit;
 157
 158free_exit:
 159        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 160                kfree_skb(skb_frag);
 161
 162exit:
 163        return rc;
 164}
 165
 166/* Send NCI data */
 167int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 168{
 169        const struct nci_conn_info *conn_info;
 170        int rc = 0;
 171
 172        pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
 173
 174        conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
 175        if (!conn_info) {
 176                rc = -EPROTO;
 177                goto free_exit;
 178        }
 179
 180        /* check if the packet need to be fragmented */
 181        if (skb->len <= conn_info->max_pkt_payload_len) {
 182                /* no need to fragment packet */
 183                nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
 184
 185                skb_queue_tail(&ndev->tx_q, skb);
 186        } else {
 187                /* fragment packet and queue the fragments */
 188                rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
 189                if (rc) {
 190                        pr_err("failed to fragment tx data packet\n");
 191                        goto free_exit;
 192                }
 193        }
 194
 195        ndev->cur_conn_id = conn_id;
 196        queue_work(ndev->tx_wq, &ndev->tx_work);
 197
 198        goto exit;
 199
 200free_exit:
 201        kfree_skb(skb);
 202
 203exit:
 204        return rc;
 205}
 206EXPORT_SYMBOL(nci_send_data);
 207
 208/* ----------------- NCI RX Data ----------------- */
 209
 210static void nci_add_rx_data_frag(struct nci_dev *ndev,
 211                                 struct sk_buff *skb,
 212                                 __u8 pbf, __u8 conn_id, __u8 status)
 213{
 214        int reassembly_len;
 215        int err = 0;
 216
 217        if (status) {
 218                err = status;
 219                goto exit;
 220        }
 221
 222        if (ndev->rx_data_reassembly) {
 223                reassembly_len = ndev->rx_data_reassembly->len;
 224
 225                /* first, make enough room for the already accumulated data */
 226                if (skb_cow_head(skb, reassembly_len)) {
 227                        pr_err("error adding room for accumulated rx data\n");
 228
 229                        kfree_skb(skb);
 230                        skb = NULL;
 231
 232                        kfree_skb(ndev->rx_data_reassembly);
 233                        ndev->rx_data_reassembly = NULL;
 234
 235                        err = -ENOMEM;
 236                        goto exit;
 237                }
 238
 239                /* second, combine the two fragments */
 240                memcpy(skb_push(skb, reassembly_len),
 241                       ndev->rx_data_reassembly->data,
 242                       reassembly_len);
 243
 244                /* third, free old reassembly */
 245                kfree_skb(ndev->rx_data_reassembly);
 246                ndev->rx_data_reassembly = NULL;
 247        }
 248
 249        if (pbf == NCI_PBF_CONT) {
 250                /* need to wait for next fragment, store skb and exit */
 251                ndev->rx_data_reassembly = skb;
 252                return;
 253        }
 254
 255exit:
 256        if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
 257                /* Data received in Target mode, forward to nfc core */
 258                err = nfc_tm_data_received(ndev->nfc_dev, skb);
 259                if (err)
 260                        pr_err("unable to handle received data\n");
 261        } else {
 262                nci_data_exchange_complete(ndev, skb, conn_id, err);
 263        }
 264}
 265
 266/* Rx Data packet */
 267void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 268{
 269        __u8 pbf = nci_pbf(skb->data);
 270        __u8 status = 0;
 271        __u8 conn_id = nci_conn_id(skb->data);
 272        const struct nci_conn_info *conn_info;
 273
 274        pr_debug("len %d\n", skb->len);
 275
 276        pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
 277                 nci_pbf(skb->data),
 278                 nci_conn_id(skb->data),
 279                 nci_plen(skb->data));
 280
 281        conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
 282        if (!conn_info)
 283                return;
 284
 285        /* strip the nci data header */
 286        skb_pull(skb, NCI_DATA_HDR_SIZE);
 287
 288        if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
 289            ndev->target_active_prot == NFC_PROTO_JEWEL ||
 290            ndev->target_active_prot == NFC_PROTO_FELICA ||
 291            ndev->target_active_prot == NFC_PROTO_ISO15693) {
 292                /* frame I/F => remove the status byte */
 293                pr_debug("frame I/F => remove the status byte\n");
 294                status = skb->data[skb->len - 1];
 295                skb_trim(skb, (skb->len - 1));
 296        }
 297
 298        nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
 299}
 300