1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2011 Instituto Nokia de Tecnologia 4 * 5 * Authors: 6 * Aloisio Almeida Jr <aloisio.almeida@openbossa.org> 7 * Lauro Ramos Venancio <lauro.venancio@openbossa.org> 8 */ 9 10 #include <linux/nfc.h> 11 #include <linux/module.h> 12 13 #include "nfc.h" 14 15 static DEFINE_RWLOCK(proto_tab_lock); 16 static const struct nfc_protocol *proto_tab[NFC_SOCKPROTO_MAX]; 17 18 static int nfc_sock_create(struct net *net, struct socket *sock, int proto, 19 int kern) 20 { 21 int rc = -EPROTONOSUPPORT; 22 23 if (net != &init_net) 24 return -EAFNOSUPPORT; 25 26 if (proto < 0 || proto >= NFC_SOCKPROTO_MAX) 27 return -EINVAL; 28 29 read_lock(&proto_tab_lock); 30 if (proto_tab[proto] && try_module_get(proto_tab[proto]->owner)) { 31 rc = proto_tab[proto]->create(net, sock, proto_tab[proto], kern); 32 module_put(proto_tab[proto]->owner); 33 } 34 read_unlock(&proto_tab_lock); 35 36 return rc; 37 } 38 39 static const struct net_proto_family nfc_sock_family_ops = { 40 .owner = THIS_MODULE, 41 .family = PF_NFC, 42 .create = nfc_sock_create, 43 }; 44 45 int nfc_proto_register(const struct nfc_protocol *nfc_proto) 46 { 47 int rc; 48 49 if (nfc_proto->id < 0 || nfc_proto->id >= NFC_SOCKPROTO_MAX) 50 return -EINVAL; 51 52 rc = proto_register(nfc_proto->proto, 0); 53 if (rc) 54 return rc; 55 56 write_lock(&proto_tab_lock); 57 if (proto_tab[nfc_proto->id]) 58 rc = -EBUSY; 59 else 60 proto_tab[nfc_proto->id] = nfc_proto; 61 write_unlock(&proto_tab_lock); 62 63 if (rc) 64 proto_unregister(nfc_proto->proto); 65 66 return rc; 67 } 68 EXPORT_SYMBOL(nfc_proto_register); 69 70 void nfc_proto_unregister(const struct nfc_protocol *nfc_proto) 71 { 72 write_lock(&proto_tab_lock); 73 proto_tab[nfc_proto->id] = NULL; 74 write_unlock(&proto_tab_lock); 75 76 proto_unregister(nfc_proto->proto); 77 } 78 EXPORT_SYMBOL(nfc_proto_unregister); 79 80 int __init af_nfc_init(void) 81 { 82 return sock_register(&nfc_sock_family_ops); 83 } 84 85 void __exit af_nfc_exit(void) 86 { 87 sock_unregister(PF_NFC); 88 } 89