net/nfc/af_nfc.c

   1 /*
   2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
   3  *
   4  * Authors:
   5  *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
   6  *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the
  20  * Free Software Foundation, Inc.,
  21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22  */
  23
  24 #include <linux/nfc.h>
  25
  26 #include "nfc.h"
  27
  28 static DEFINE_RWLOCK(proto_tab_lock);
  29 static const struct nfc_protocol *proto_tab[NFC_SOCKPROTO_MAX];
  30
  31 static int nfc_sock_create(struct net *net, struct socket *sock, int proto,
  32                                                                 int kern)
  33 {
  34         int rc = -EPROTONOSUPPORT;
  35
  36         if (net != &init_net)
  37                 return -EAFNOSUPPORT;
  38
  39         if (proto < 0 || proto >= NFC_SOCKPROTO_MAX)
  40                 return -EINVAL;
  41
  42         read_lock(&proto_tab_lock);
  43         if (proto_tab[proto] && try_module_get(proto_tab[proto]->owner)) {
  44                 rc = proto_tab[proto]->create(net, sock, proto_tab[proto]);
  45                 module_put(proto_tab[proto]->owner);
  46         }
  47         read_unlock(&proto_tab_lock);
  48
  49         return rc;
  50 }
  51
  52 static struct net_proto_family nfc_sock_family_ops = {
  53         .owner  = THIS_MODULE,
  54         .family = PF_NFC,
  55         .create = nfc_sock_create,
  56 };
  57
  58 int nfc_proto_register(const struct nfc_protocol *nfc_proto)
  59 {
  60         int rc;
  61
  62         if (nfc_proto->id < 0 || nfc_proto->id >= NFC_SOCKPROTO_MAX)
  63                 return -EINVAL;
  64
  65         rc = proto_register(nfc_proto->proto, 0);
  66         if (rc)
  67                 return rc;
  68
  69         write_lock(&proto_tab_lock);
  70         if (proto_tab[nfc_proto->id])
  71                 rc = -EBUSY;
  72         else
  73                 proto_tab[nfc_proto->id] = nfc_proto;
  74         write_unlock(&proto_tab_lock);
  75
  76         return rc;
  77 }
  78 EXPORT_SYMBOL(nfc_proto_register);
  79
  80 void nfc_proto_unregister(const struct nfc_protocol *nfc_proto)
  81 {
  82         write_lock(&proto_tab_lock);
  83         proto_tab[nfc_proto->id] = NULL;
  84         write_unlock(&proto_tab_lock);
  85
  86         proto_unregister(nfc_proto->proto);
  87 }
  88 EXPORT_SYMBOL(nfc_proto_unregister);
  89
  90 int __init af_nfc_init(void)
  91 {
  92         return sock_register(&nfc_sock_family_ops);
  93 }
  94
  95 void af_nfc_exit(void)
  96 {
  97         sock_unregister(PF_NFC);
  98 }