root/net/nfc/nci/data.c

DEFINITIONS

1. nci_data_exchange_complete
2. nci_push_data_hdr
3. nci_conn_max_data_pkt_payload_size
4. nci_queue_tx_data_frags
5. nci_send_data
6. nci_add_rx_data_frag
7. nci_rx_data_packet

   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 */
  26 void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
  27                                 __u8 conn_id, int err)
  28 {
  29         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 
  58 exit:
  59         clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
  60 }
  61 
  62 /* ----------------- NCI TX Data ----------------- */
  63 
  64 static 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 
  81 int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
  82 {
  83         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 }
  91 EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
  92 
  93 static int nci_queue_tx_data_frags(struct nci_dev *ndev,
  94                                    __u8 conn_id,
  95                                    struct sk_buff *skb) {
  96         struct nci_conn_info    *conn_info;
  97         int total_len = skb->len;
  98         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 
 158 free_exit:
 159         while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 160                 kfree_skb(skb_frag);
 161 
 162 exit:
 163         return rc;
 164 }
 165 
 166 /* Send NCI data */
 167 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 168 {
 169         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 
 200 free_exit:
 201         kfree_skb(skb);
 202 
 203 exit:
 204         return rc;
 205 }
 206 EXPORT_SYMBOL(nci_send_data);
 207 
 208 /* ----------------- NCI RX Data ----------------- */
 209 
 210 static 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 
 255 exit:
 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 */
 267 void 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         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 }