Line data Source code
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) 2009-2012, Masashi Honma <masashi.honma@gmail.com>
5 : *
6 : * This software may be distributed under the terms of the BSD license.
7 : * See README for more details.
8 : */
9 :
10 : #include "includes.h"
11 : #include "common.h"
12 : #include "wps/wps.h"
13 :
14 : #define FLAG_MESSAGE_BEGIN (1 << 7)
15 : #define FLAG_MESSAGE_END (1 << 6)
16 : #define FLAG_CHUNK (1 << 5)
17 : #define FLAG_SHORT_RECORD (1 << 4)
18 : #define FLAG_ID_LENGTH_PRESENT (1 << 3)
19 : #define FLAG_TNF_NFC_FORUM (0x01)
20 : #define FLAG_TNF_RFC2046 (0x02)
21 :
22 : struct ndef_record {
23 : const u8 *type;
24 : const u8 *id;
25 : const u8 *payload;
26 : u8 type_length;
27 : u8 id_length;
28 : u32 payload_length;
29 : u32 total_length;
30 : };
31 :
32 : static char wifi_handover_type[] = "application/vnd.wfa.wsc";
33 : static char p2p_handover_type[] = "application/vnd.wfa.p2p";
34 :
35 65 : static int ndef_parse_record(const u8 *data, u32 size,
36 : struct ndef_record *record)
37 : {
38 65 : const u8 *pos = data + 1;
39 :
40 65 : if (size < 2)
41 0 : return -1;
42 65 : record->type_length = *pos++;
43 65 : if (data[0] & FLAG_SHORT_RECORD) {
44 62 : if (size < 3)
45 0 : return -1;
46 62 : record->payload_length = *pos++;
47 : } else {
48 3 : if (size < 6)
49 3 : return -1;
50 0 : record->payload_length = ntohl(*(u32 *)pos);
51 0 : pos += sizeof(u32);
52 : }
53 :
54 62 : if (data[0] & FLAG_ID_LENGTH_PRESENT) {
55 0 : if ((int) size < pos - data + 1)
56 0 : return -1;
57 0 : record->id_length = *pos++;
58 : } else
59 62 : record->id_length = 0;
60 :
61 62 : record->type = record->type_length == 0 ? NULL : pos;
62 62 : pos += record->type_length;
63 :
64 62 : record->id = record->id_length == 0 ? NULL : pos;
65 62 : pos += record->id_length;
66 :
67 62 : record->payload = record->payload_length == 0 ? NULL : pos;
68 62 : pos += record->payload_length;
69 :
70 62 : record->total_length = pos - data;
71 62 : if (record->total_length > size)
72 0 : return -1;
73 62 : return 0;
74 : }
75 :
76 :
77 65 : static struct wpabuf * ndef_parse_records(const struct wpabuf *buf,
78 : int (*filter)(struct ndef_record *))
79 : {
80 : struct ndef_record record;
81 65 : int len = wpabuf_len(buf);
82 65 : const u8 *data = wpabuf_head(buf);
83 :
84 138 : while (len > 0) {
85 65 : if (ndef_parse_record(data, len, &record) < 0) {
86 3 : wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
87 3 : return NULL;
88 : }
89 62 : if (filter == NULL || filter(&record))
90 54 : return wpabuf_alloc_copy(record.payload,
91 54 : record.payload_length);
92 8 : data += record.total_length;
93 8 : len -= record.total_length;
94 : }
95 8 : wpa_printf(MSG_ERROR, "NDEF : Record not found");
96 8 : return NULL;
97 : }
98 :
99 :
100 67 : static struct wpabuf * ndef_build_record(u8 flags, void *type,
101 : u8 type_length, void *id,
102 : u8 id_length,
103 : const struct wpabuf *payload)
104 : {
105 : struct wpabuf *record;
106 : size_t total_len;
107 : int short_record;
108 : u8 local_flag;
109 67 : size_t payload_length = wpabuf_len(payload);
110 :
111 67 : short_record = payload_length < 256 ? 1 : 0;
112 :
113 67 : total_len = 2; /* flag + type length */
114 : /* payload length */
115 67 : total_len += short_record ? sizeof(u8) : sizeof(u32);
116 67 : if (id_length > 0)
117 0 : total_len += 1;
118 67 : total_len += type_length + id_length + payload_length;
119 67 : record = wpabuf_alloc(total_len);
120 67 : if (record == NULL) {
121 0 : wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
122 : "record for build");
123 0 : return NULL;
124 : }
125 :
126 67 : local_flag = flags;
127 67 : if (id_length > 0)
128 0 : local_flag |= FLAG_ID_LENGTH_PRESENT;
129 67 : if (short_record)
130 67 : local_flag |= FLAG_SHORT_RECORD;
131 67 : wpabuf_put_u8(record, local_flag);
132 :
133 67 : wpabuf_put_u8(record, type_length);
134 :
135 67 : if (short_record)
136 67 : wpabuf_put_u8(record, payload_length);
137 : else
138 0 : wpabuf_put_be32(record, payload_length);
139 :
140 67 : if (id_length > 0)
141 0 : wpabuf_put_u8(record, id_length);
142 67 : wpabuf_put_data(record, type, type_length);
143 67 : wpabuf_put_data(record, id, id_length);
144 67 : wpabuf_put_buf(record, payload);
145 67 : return record;
146 : }
147 :
148 :
149 38 : static int wifi_filter(struct ndef_record *record)
150 : {
151 76 : if (record->type == NULL ||
152 38 : record->type_length != os_strlen(wifi_handover_type))
153 0 : return 0;
154 38 : if (os_memcmp(record->type, wifi_handover_type,
155 : os_strlen(wifi_handover_type)) != 0)
156 8 : return 0;
157 30 : return 1;
158 : }
159 :
160 :
161 40 : struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf)
162 : {
163 40 : return ndef_parse_records(buf, wifi_filter);
164 : }
165 :
166 :
167 41 : struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
168 : {
169 41 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
170 : FLAG_TNF_RFC2046, wifi_handover_type,
171 41 : os_strlen(wifi_handover_type), NULL, 0, buf);
172 : }
173 :
174 :
175 24 : static int p2p_filter(struct ndef_record *record)
176 : {
177 48 : if (record->type == NULL ||
178 24 : record->type_length != os_strlen(p2p_handover_type))
179 0 : return 0;
180 24 : if (os_memcmp(record->type, p2p_handover_type,
181 : os_strlen(p2p_handover_type)) != 0)
182 0 : return 0;
183 24 : return 1;
184 : }
185 :
186 :
187 25 : struct wpabuf * ndef_parse_p2p(const struct wpabuf *buf)
188 : {
189 25 : return ndef_parse_records(buf, p2p_filter);
190 : }
191 :
192 :
193 26 : struct wpabuf * ndef_build_p2p(const struct wpabuf *buf)
194 : {
195 26 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
196 : FLAG_TNF_RFC2046, p2p_handover_type,
197 26 : os_strlen(p2p_handover_type), NULL, 0, buf);
198 : }
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