hostap/src/wps/ndef.c

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2009-03-06 15:16:22 +01:00
/*
* NDEF(NFC Data Exchange Format) routines for Wi-Fi Protected Setup
* Reference is "NFCForum-TS-NDEF_1.0 2006-07-24".
* Copyright (c) 2009-2012, Masashi Honma <masashi.honma@gmail.com>
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*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
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*/
#include "includes.h"
#include "common.h"
#include "wps/wps.h"
#define FLAG_MESSAGE_BEGIN (1 << 7)
#define FLAG_MESSAGE_END (1 << 6)
#define FLAG_CHUNK (1 << 5)
#define FLAG_SHORT_RECORD (1 << 4)
#define FLAG_ID_LENGTH_PRESENT (1 << 3)
#define FLAG_TNF_NFC_FORUM (0x01)
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#define FLAG_TNF_RFC2046 (0x02)
struct ndef_record {
const u8 *type;
const u8 *id;
const u8 *payload;
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u8 type_length;
u8 id_length;
u32 payload_length;
u32 total_length;
};
static char wifi_handover_type[] = "application/vnd.wfa.wsc";
static int ndef_parse_record(const u8 *data, u32 size,
struct ndef_record *record)
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{
const u8 *pos = data + 1;
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if (size < 2)
return -1;
record->type_length = *pos++;
if (data[0] & FLAG_SHORT_RECORD) {
if (size < 3)
return -1;
record->payload_length = *pos++;
} else {
if (size < 6)
return -1;
record->payload_length = ntohl(*(u32 *)pos);
pos += sizeof(u32);
}
if (data[0] & FLAG_ID_LENGTH_PRESENT) {
if ((int) size < pos - data + 1)
return -1;
record->id_length = *pos++;
} else
record->id_length = 0;
record->type = record->type_length == 0 ? NULL : pos;
pos += record->type_length;
record->id = record->id_length == 0 ? NULL : pos;
pos += record->id_length;
record->payload = record->payload_length == 0 ? NULL : pos;
pos += record->payload_length;
record->total_length = pos - data;
if (record->total_length > size)
return -1;
return 0;
}
static struct wpabuf * ndef_parse_records(const struct wpabuf *buf,
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int (*filter)(struct ndef_record *))
{
struct ndef_record record;
int len = wpabuf_len(buf);
const u8 *data = wpabuf_head(buf);
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while (len > 0) {
if (ndef_parse_record(data, len, &record) < 0) {
wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
return NULL;
}
if (filter == NULL || filter(&record))
return wpabuf_alloc_copy(record.payload,
record.payload_length);
data += record.total_length;
len -= record.total_length;
}
wpa_printf(MSG_ERROR, "NDEF : Record not found");
return NULL;
}
static struct wpabuf * ndef_build_record(u8 flags, void *type,
u8 type_length, void *id,
u8 id_length,
const struct wpabuf *payload)
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{
struct wpabuf *record;
size_t total_len;
int short_record;
u8 local_flag;
size_t payload_length = wpabuf_len(payload);
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short_record = payload_length < 256 ? 1 : 0;
total_len = 2; /* flag + type length */
/* payload length */
total_len += short_record ? sizeof(u8) : sizeof(u32);
if (id_length > 0)
total_len += 1;
total_len += type_length + id_length + payload_length;
record = wpabuf_alloc(total_len);
if (record == NULL) {
wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
"record for build");
return NULL;
}
local_flag = flags;
if (id_length > 0)
local_flag |= FLAG_ID_LENGTH_PRESENT;
if (short_record)
local_flag |= FLAG_SHORT_RECORD;
wpabuf_put_u8(record, local_flag);
wpabuf_put_u8(record, type_length);
if (short_record)
wpabuf_put_u8(record, payload_length);
else
wpabuf_put_be32(record, payload_length);
if (id_length > 0)
wpabuf_put_u8(record, id_length);
wpabuf_put_data(record, type, type_length);
wpabuf_put_data(record, id, id_length);
wpabuf_put_buf(record, payload);
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return record;
}
static int wifi_filter(struct ndef_record *record)
{
if (record->type_length != os_strlen(wifi_handover_type))
return 0;
if (os_memcmp(record->type, wifi_handover_type,
os_strlen(wifi_handover_type)) != 0)
return 0;
return 1;
}
struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf)
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{
return ndef_parse_records(buf, wifi_filter);
}
struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
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{
return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
FLAG_TNF_RFC2046, wifi_handover_type,
os_strlen(wifi_handover_type), NULL, 0, buf);
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}
struct wpabuf * ndef_build_wifi_hr(void)
{
struct wpabuf *rn, *cr, *ac_payload, *ac, *hr_payload, *hr;
struct wpabuf *carrier, *hc;
rn = wpabuf_alloc(2);
if (rn == NULL)
return NULL;
wpabuf_put_be16(rn, os_random() & 0xffff);
cr = ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_TNF_NFC_FORUM, "cr", 2,
NULL, 0, rn);
wpabuf_free(rn);
if (cr == NULL)
return NULL;
ac_payload = wpabuf_alloc(4);
if (ac_payload == NULL) {
wpabuf_free(cr);
return NULL;
}
wpabuf_put_u8(ac_payload, 0x01); /* Carrier Flags: CRS=1 "active" */
wpabuf_put_u8(ac_payload, 0x01); /* Carrier Data Reference Length */
wpabuf_put_u8(ac_payload, '0'); /* Carrier Data Reference: "0" */
wpabuf_put_u8(ac_payload, 0); /* Aux Data Reference Count */
ac = ndef_build_record(FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "ac", 2,
NULL, 0, ac_payload);
wpabuf_free(ac_payload);
if (ac == NULL) {
wpabuf_free(cr);
return NULL;
}
hr_payload = wpabuf_alloc(1 + wpabuf_len(cr) + wpabuf_len(ac));
if (hr_payload == NULL) {
wpabuf_free(cr);
wpabuf_free(ac);
return NULL;
}
wpabuf_put_u8(hr_payload, 0x12); /* Connection Handover Version 1.2 */
wpabuf_put_buf(hr_payload, cr);
wpabuf_put_buf(hr_payload, ac);
wpabuf_free(cr);
wpabuf_free(ac);
hr = ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_TNF_NFC_FORUM, "Hr", 2,
NULL, 0, hr_payload);
wpabuf_free(hr_payload);
if (hr == NULL)
return NULL;
carrier = wpabuf_alloc(2 + os_strlen(wifi_handover_type));
if (carrier == NULL) {
wpabuf_free(hr);
return NULL;
}
wpabuf_put_u8(carrier, 0x02); /* Carrier Type Format */
wpabuf_put_u8(carrier, os_strlen(wifi_handover_type));
wpabuf_put_str(carrier, wifi_handover_type);
hc = ndef_build_record(FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "Hc", 2,
"0", 1, carrier);
wpabuf_free(carrier);
if (hc == NULL) {
wpabuf_free(hr);
return NULL;
}
return wpabuf_concat(hr, hc);
}