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) 2009-2012, Masashi Honma <masashi.honma@gmail.com>
6 * This software may be distributed under the terms of the BSD license.
7 * See README for more details.
13 #include "wps/wps_i.h"
15 #define FLAG_MESSAGE_BEGIN (1 << 7)
16 #define FLAG_MESSAGE_END (1 << 6)
17 #define FLAG_CHUNK (1 << 5)
18 #define FLAG_SHORT_RECORD (1 << 4)
19 #define FLAG_ID_LENGTH_PRESENT (1 << 3)
20 #define FLAG_TNF_NFC_FORUM (0x01)
21 #define FLAG_TNF_RFC2046 (0x02)
33 static char wifi_handover_type[] = "application/vnd.wfa.wsc";
35 static int ndef_parse_record(const u8 *data, u32 size,
36 struct ndef_record *record)
38 const u8 *pos = data + 1;
42 record->type_length = *pos++;
43 if (data[0] & FLAG_SHORT_RECORD) {
46 record->payload_length = *pos++;
50 record->payload_length = ntohl(*(u32 *)pos);
54 if (data[0] & FLAG_ID_LENGTH_PRESENT) {
55 if ((int) size < pos - data + 1)
57 record->id_length = *pos++;
59 record->id_length = 0;
61 record->type = record->type_length == 0 ? NULL : pos;
62 pos += record->type_length;
64 record->id = record->id_length == 0 ? NULL : pos;
65 pos += record->id_length;
67 record->payload = record->payload_length == 0 ? NULL : pos;
68 pos += record->payload_length;
70 record->total_length = pos - data;
71 if (record->total_length > size)
77 static struct wpabuf * ndef_parse_records(const struct wpabuf *buf,
78 int (*filter)(struct ndef_record *))
80 struct ndef_record record;
81 int len = wpabuf_len(buf);
82 const u8 *data = wpabuf_head(buf);
85 if (ndef_parse_record(data, len, &record) < 0) {
86 wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
89 if (filter == NULL || filter(&record))
90 return wpabuf_alloc_copy(record.payload,
91 record.payload_length);
92 data += record.total_length;
93 len -= record.total_length;
95 wpa_printf(MSG_ERROR, "NDEF : Record not found");
100 static struct wpabuf * ndef_build_record(u8 flags, void *type,
101 u8 type_length, void *id,
103 const struct wpabuf *payload)
105 struct wpabuf *record;
109 size_t payload_length = wpabuf_len(payload);
111 short_record = payload_length < 256 ? 1 : 0;
113 total_len = 2; /* flag + type length */
115 total_len += short_record ? sizeof(u8) : sizeof(u32);
118 total_len += type_length + id_length + payload_length;
119 record = wpabuf_alloc(total_len);
120 if (record == NULL) {
121 wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
128 local_flag |= FLAG_ID_LENGTH_PRESENT;
130 local_flag |= FLAG_SHORT_RECORD;
131 wpabuf_put_u8(record, local_flag);
133 wpabuf_put_u8(record, type_length);
136 wpabuf_put_u8(record, payload_length);
138 wpabuf_put_be32(record, payload_length);
141 wpabuf_put_u8(record, id_length);
142 wpabuf_put_data(record, type, type_length);
143 wpabuf_put_data(record, id, id_length);
144 wpabuf_put_buf(record, payload);
149 static int wifi_filter(struct ndef_record *record)
151 if (record->type_length != os_strlen(wifi_handover_type))
153 if (os_memcmp(record->type, wifi_handover_type,
154 os_strlen(wifi_handover_type)) != 0)
160 struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf)
162 return ndef_parse_records(buf, wifi_filter);
166 struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
168 return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
169 FLAG_TNF_RFC2046, wifi_handover_type,
170 os_strlen(wifi_handover_type), NULL, 0, buf);
174 struct wpabuf * ndef_build_wifi_hr(void)
176 struct wpabuf *rn, *cr, *ac_payload, *ac, *hr_payload, *hr;
177 struct wpabuf *carrier, *hc;
179 rn = wpabuf_alloc(2);
182 wpabuf_put_be16(rn, os_random() & 0xffff);
184 cr = ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_TNF_NFC_FORUM, "cr", 2,
191 ac_payload = wpabuf_alloc(4);
192 if (ac_payload == NULL) {
196 wpabuf_put_u8(ac_payload, 0x01); /* Carrier Flags: CRS=1 "active" */
197 wpabuf_put_u8(ac_payload, 0x01); /* Carrier Data Reference Length */
198 wpabuf_put_u8(ac_payload, '0'); /* Carrier Data Reference: "0" */
199 wpabuf_put_u8(ac_payload, 0); /* Aux Data Reference Count */
201 ac = ndef_build_record(FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "ac", 2,
202 NULL, 0, ac_payload);
203 wpabuf_free(ac_payload);
209 hr_payload = wpabuf_alloc(1 + wpabuf_len(cr) + wpabuf_len(ac));
210 if (hr_payload == NULL) {
216 wpabuf_put_u8(hr_payload, 0x12); /* Connection Handover Version 1.2 */
217 wpabuf_put_buf(hr_payload, cr);
218 wpabuf_put_buf(hr_payload, ac);
222 hr = ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_TNF_NFC_FORUM, "Hr", 2,
223 NULL, 0, hr_payload);
224 wpabuf_free(hr_payload);
228 carrier = wpabuf_alloc(2 + os_strlen(wifi_handover_type));
229 if (carrier == NULL) {
233 wpabuf_put_u8(carrier, 0x02); /* Carrier Type Format */
234 wpabuf_put_u8(carrier, os_strlen(wifi_handover_type));
235 wpabuf_put_str(carrier, wifi_handover_type);
237 hc = ndef_build_record(FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "Hc", 2,
239 wpabuf_free(carrier);
245 return wpabuf_concat(hr, hc);