www.project-moonshot.org Git - mech_eap.orig/blob - libeap/src/wps/ndef.c

   1 /*
   2  * NDEF(NFC Data Exchange Format) routines for Wi-Fi Protected Setup
   3  *   Reference is "NFCForum-TS-NDEF_1.0 2006-07-24".
   4  * Copyright (c) 2009, Masashi Honma <honma@ictec.co.jp>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Alternatively, this software may be distributed under the terms of BSD
  11  * license.
  12  *
  13  * See README and COPYING for more details.
  14  */
  15
  16 #include "includes.h"
  17 #include "common.h"
  18 #include "wps/wps.h"
  19 #include "wps/wps_i.h"
  20
  21 #define FLAG_MESSAGE_BEGIN (1 << 7)
  22 #define FLAG_MESSAGE_END (1 << 6)
  23 #define FLAG_CHUNK (1 << 5)
  24 #define FLAG_SHORT_RECORD (1 << 4)
  25 #define FLAG_ID_LENGTH_PRESENT (1 << 3)
  26 #define FLAG_TNF_RFC2046 (0x02)
  27
  28 struct ndef_record {
  29         u8 *type;
  30         u8 *id;
  31         u8 *payload;
  32         u8 type_length;
  33         u8 id_length;
  34         u32 payload_length;
  35         u32 total_length;
  36 };
  37
  38 static char wifi_handover_type[] = "application/vnd.wfa.wsc";
  39
  40 static int ndef_parse_record(u8 *data, u32 size, struct ndef_record *record)
  41 {
  42         u8 *pos = data + 1;
  43
  44         if (size < 2)
  45                 return -1;
  46         record->type_length = *pos++;
  47         if (data[0] & FLAG_SHORT_RECORD) {
  48                 if (size < 3)
  49                         return -1;
  50                 record->payload_length = *pos++;
  51         } else {
  52                 if (size < 6)
  53                         return -1;
  54                 record->payload_length = ntohl(*(u32 *)pos);
  55                 pos += sizeof(u32);
  56         }
  57
  58         if (data[0] & FLAG_ID_LENGTH_PRESENT) {
  59                 if ((int) size < pos - data + 1)
  60                         return -1;
  61                 record->id_length = *pos++;
  62         } else
  63                 record->id_length = 0;
  64
  65         record->type = record->type_length == 0 ? NULL : pos;
  66         pos += record->type_length;
  67
  68         record->id = record->id_length == 0 ? NULL : pos;
  69         pos += record->id_length;
  70
  71         record->payload = record->payload_length == 0 ? NULL : pos;
  72         pos += record->payload_length;
  73
  74         record->total_length = pos - data;
  75         if (record->total_length > size)
  76                 return -1;
  77         return 0;
  78 }
  79
  80
  81 static struct wpabuf * ndef_parse_records(struct wpabuf *buf,
  82                                           int (*filter)(struct ndef_record *))
  83 {
  84         struct ndef_record record;
  85         int len = wpabuf_len(buf);
  86         u8 *data = wpabuf_mhead(buf);
  87
  88         while (len > 0) {
  89                 if (ndef_parse_record(data, len, &record) < 0) {
  90                         wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
  91                         return NULL;
  92                 }
  93                 if (filter == NULL || filter(&record))
  94                         return wpabuf_alloc_copy(record.payload,
  95                                                  record.payload_length);
  96                 data += record.total_length;
  97                 len -= record.total_length;
  98         }
  99         wpa_printf(MSG_ERROR, "NDEF : Record not found");
 100         return NULL;
 101 }
 102
 103
 104 static struct wpabuf * ndef_build_record(u8 flags, void *type,
 105                                          u8 type_length, void *id,
 106                                          u8 id_length, void *payload,
 107                                          u32 payload_length)
 108 {
 109         struct wpabuf *record;
 110         size_t total_len;
 111         int short_record;
 112         u8 local_flag;
 113
 114         short_record = payload_length < 256 ? 1 : 0;
 115
 116         total_len = 2; /* flag + type length */
 117         /* payload length */
 118         total_len += short_record ? sizeof(u8) : sizeof(u32);
 119         if (id_length > 0)
 120                 total_len += 1;
 121         total_len += type_length + id_length + payload_length;
 122         record = wpabuf_alloc(total_len);
 123         if (record == NULL) {
 124                 wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
 125                            "record for build");
 126                 return NULL;
 127         }
 128
 129         local_flag = flags;
 130         if (id_length > 0)
 131                 local_flag |= FLAG_ID_LENGTH_PRESENT;
 132         if (short_record)
 133                 local_flag |= FLAG_SHORT_RECORD;
 134         wpabuf_put_u8(record, local_flag);
 135
 136         wpabuf_put_u8(record, type_length);
 137
 138         if (short_record)
 139                 wpabuf_put_u8(record, payload_length);
 140         else
 141                 wpabuf_put_be32(record, payload_length);
 142
 143         if (id_length > 0)
 144                 wpabuf_put_u8(record, id_length);
 145         wpabuf_put_data(record, type, type_length);
 146         wpabuf_put_data(record, id, id_length);
 147         wpabuf_put_data(record, payload, payload_length);
 148         return record;
 149 }
 150
 151
 152 static int wifi_filter(struct ndef_record *record)
 153 {
 154         if (record->type_length != os_strlen(wifi_handover_type))
 155                 return 0;
 156         if (os_memcmp(record->type, wifi_handover_type,
 157                       os_strlen(wifi_handover_type)) != 0)
 158                 return 0;
 159         return 1;
 160 }
 161
 162
 163 struct wpabuf * ndef_parse_wifi(struct wpabuf *buf)
 164 {
 165         return ndef_parse_records(buf, wifi_filter);
 166 }
 167
 168
 169 struct wpabuf * ndef_build_wifi(struct wpabuf *buf)
 170 {
 171         return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
 172                                  FLAG_TNF_RFC2046, wifi_handover_type,
 173                                  os_strlen(wifi_handover_type), NULL, 0,
 174                                  wpabuf_mhead(buf), wpabuf_len(buf));
 175 }