git.maemo.org Git - wpasupplicant/blob - 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
  20 #define FLAG_MESSAGE_BEGIN (1 << 7)
  21 #define FLAG_MESSAGE_END (1 << 6)
  22 #define FLAG_CHUNK (1 << 5)
  23 #define FLAG_SHORT_RECORD (1 << 4)
  24 #define FLAG_ID_LENGTH_PRESENT (1 << 3)
  25 #define FLAG_TNF_RFC2046 (0x02)
  26
  27 struct ndef_record {
  28         u8 *type;
  29         u8 *id;
  30         u8 *payload;
  31         u8 type_length;
  32         u8 id_length;
  33         u32 payload_length;
  34         u32 total_length;
  35 };
  36
  37 static char wifi_handover_type[] = "application/vnd.wfa.wsc";
  38
  39 static int ndef_parse_record(u8 *data, u32 size, struct ndef_record *record)
  40 {
  41         u8 *pos = data + 1;
  42
  43         if (size < 2)
  44                 return -1;
  45         record->type_length = *pos++;
  46         if (data[0] & FLAG_SHORT_RECORD) {
  47                 if (size < 3)
  48                         return -1;
  49                 record->payload_length = *pos++;
  50         } else {
  51                 if (size < 6)
  52                         return -1;
  53                 record->payload_length = ntohl(*(u32 *)pos);
  54                 pos += sizeof(u32);
  55         }
  56
  57         if (data[0] & FLAG_ID_LENGTH_PRESENT) {
  58                 if ((int) size < pos - data + 1)
  59                         return -1;
  60                 record->id_length = *pos++;
  61         } else
  62                 record->id_length = 0;
  63
  64         record->type = record->type_length == 0 ? NULL : pos;
  65         pos += record->type_length;
  66
  67         record->id = record->id_length == 0 ? NULL : pos;
  68         pos += record->id_length;
  69
  70         record->payload = record->payload_length == 0 ? NULL : pos;
  71         pos += record->payload_length;
  72
  73         record->total_length = pos - data;
  74         if (record->total_length > size)
  75                 return -1;
  76         return 0;
  77 }
  78
  79
  80 static struct wpabuf * ndef_parse_records(struct wpabuf *buf,
  81                                           int (*filter)(struct ndef_record *))
  82 {
  83         struct ndef_record record;
  84         int len = wpabuf_len(buf);
  85         u8 *data = wpabuf_mhead(buf);
  86
  87         while (len > 0) {
  88                 if (ndef_parse_record(data, len, &record) < 0) {
  89                         wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
  90                         return NULL;
  91                 }
  92                 if (filter == NULL || filter(&record))
  93                         return wpabuf_alloc_copy(record.payload,
  94                                                  record.payload_length);
  95                 data += record.total_length;
  96                 len -= record.total_length;
  97         }
  98         wpa_printf(MSG_ERROR, "NDEF : Record not found");
  99         return NULL;
 100 }
 101
 102
 103 static struct wpabuf * ndef_build_record(u8 flags, void *type,
 104                                          u8 type_length, void *id,
 105                                          u8 id_length, void *payload,
 106                                          u32 payload_length)
 107 {
 108         struct wpabuf *record;
 109         size_t total_len;
 110         int short_record;
 111         u8 local_flag;
 112
 113         short_record = payload_length < 256 ? 1 : 0;
 114
 115         total_len = 2; /* flag + type length */
 116         /* payload length */
 117         total_len += short_record ? sizeof(u8) : sizeof(u32);
 118         if (id_length > 0)
 119                 total_len += 1;
 120         total_len += type_length + id_length + payload_length;
 121         record = wpabuf_alloc(total_len);
 122         if (record == NULL) {
 123                 wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
 124                            "record for build");
 125                 return NULL;
 126         }
 127
 128         local_flag = flags;
 129         if (id_length > 0)
 130                 local_flag |= FLAG_ID_LENGTH_PRESENT;
 131         if (short_record)
 132                 local_flag |= FLAG_SHORT_RECORD;
 133         wpabuf_put_u8(record, local_flag);
 134
 135         wpabuf_put_u8(record, type_length);
 136
 137         if (short_record)
 138                 wpabuf_put_u8(record, payload_length);
 139         else
 140                 wpabuf_put_be32(record, payload_length);
 141
 142         if (id_length > 0)
 143                 wpabuf_put_u8(record, id_length);
 144         wpabuf_put_data(record, type, type_length);
 145         wpabuf_put_data(record, id, id_length);
 146         wpabuf_put_data(record, payload, payload_length);
 147         return record;
 148 }
 149
 150
 151 static int wifi_filter(struct ndef_record *record)
 152 {
 153         if (record->type_length != os_strlen(wifi_handover_type))
 154                 return 0;
 155         if (os_memcmp(record->type, wifi_handover_type,
 156                       os_strlen(wifi_handover_type)) != 0)
 157                 return 0;
 158         return 1;
 159 }
 160
 161
 162 struct wpabuf * ndef_parse_wifi(struct wpabuf *buf)
 163 {
 164         return ndef_parse_records(buf, wifi_filter);
 165 }
 166
 167
 168 struct wpabuf * ndef_build_wifi(struct wpabuf *buf)
 169 {
 170         return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
 171                                  FLAG_TNF_RFC2046, wifi_handover_type,
 172                                  os_strlen(wifi_handover_type), NULL, 0,
 173                                  wpabuf_mhead(buf), wpabuf_len(buf));
 174 }