Hiroshi Nakata
This program calculate location of Wi-Fi receiver, by using AP beacon. Please check the Japanese magazine "Interface 2012/12".
Diff: WiFiScanner.h
- Revision:
- 0:4eaf38ccb19c
- Child:
- 1:2f2f793fcf4f
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/WiFiScanner.h Fri Aug 24 03:21:43 2012 +0000
@@ -0,0 +1,393 @@
+#include <string.h>
+
+#define BAUD_RATE 115200
+
+#define MULTI_CHANNEL
+#ifdef MULTI_CHANNEL
+#define TOTAL_CHANNELS 13
+#else
+#define TOTAL_CHANNELS 1
+#endif
+#define MAX_AP_COUNT (10 * TOTAL_CHANNELS)
+//#define PASSIVE_SCAN // uncommnet here when you need passive scan
+
+#define CR '\r'
+#define SHORT_WAIT 0.00032
+#define BUFF_LEN 4096
+#define ESSID_LEN 33
+#define MACADDR_LEN 6
+
+struct apinfo {
+ unsigned char essid[ESSID_LEN];
+ unsigned char bssid[MACADDR_LEN];
+ int power;
+};
+
+struct apinfo apinfos[MAX_AP_COUNT];
+int apinfo_count;
+
+Serial wifi(p13, p14);
+
+DigitalOut PRST(p15);
+DigitalOut UART_CTS(p16);
+DigitalIn UART_RTS(p17);
+
+class WiFiScanner {
+private:
+ int sequence;
+ unsigned char buff[BUFF_LEN];
+
+ void wifiReadWait()
+ {
+ UART_CTS = 0;
+ }
+
+ void wifiReadEnd()
+ {
+ UART_CTS = 1;
+ }
+
+ void wifiPutc(int c)
+ {
+ while (!wifi.writeable())
+ ; // empty loop body
+ wifi.putc(c);
+ }
+
+ int wifiGetc()
+ {
+ while (!wifi.readable())
+ ; // empty loop body
+ return wifi.getc();
+ }
+
+ int num2hex(int i)
+ {
+ static const char hexadecimal[] = "0123456789ABCDEF";
+
+ if ( i < 0 || i > 15 )
+ return '0';
+
+ return ((int)hexadecimal[i]);
+ }
+
+ int hex2num(int i)
+ {
+ switch (i) {
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ return (i - '0');
+ case 'A':
+ case 'B':
+ case 'C':
+ case 'D':
+ case 'E':
+ case 'F':
+ return ( i - 'A' + 10);
+ case 'a':
+ case 'b':
+ case 'c':
+ case 'd':
+ case 'e':
+ case 'f':
+ return ( i - 'a' + 10);
+ }
+ return (-1);
+ }
+
+ void delayedPutc(unsigned char c)
+ {
+ wifiPutc(c);
+ wait(SHORT_WAIT);
+ }
+
+
+ void wifiWrite(unsigned char *data)
+ {
+ int i;
+ int len = ((int)data[3]) * 256 + data[2];
+
+ delayedPutc('*');
+ delayedPutc(num2hex((len >> 4) & 0xf));
+ delayedPutc(num2hex(len & 0xf));
+ delayedPutc('4');
+ delayedPutc(num2hex((len >> 8) & 0xf));
+ for ( i = 0; i < len; i++ ) {
+ if ( i == 1 ) {
+ delayedPutc(num2hex((sequence >> 4) & 0x0f));
+ delayedPutc(num2hex(sequence & 0x0f));
+ } else {
+ delayedPutc(num2hex((data[i] >> 4) & 0x0f));
+ delayedPutc(num2hex(data[i] & 0x0f));
+ }
+ }
+ delayedPutc(CR);
+ sequence++;
+ }
+
+ int wifiRead()
+ {
+ int len = 0;
+ int index = 0;
+ int c;
+
+ wifiReadWait();
+ while (true) {
+ c = wifiGetc();
+ if ( c == CR ) {
+ if ( (index - 5) >= len * 2 ) {
+ break;
+ }
+
+ len = 0;
+ index = 0;
+ continue;
+ }
+ if ( index == 0 ) {
+ if ( c == '*' ) {
+ index++;
+ } else {
+ while (wifiGetc() != CR)
+ ; //empty loop body
+ }
+ continue;
+ }
+
+ c = hex2num(c);
+ if ( c < 0 ) {
+ while (wifiGetc() != CR)
+ ; // empty loop body
+ len = 0;
+ index = 0;
+ continue;
+ }
+ if ( index == 1 ) {
+ len = c << 4;
+ } else if ( index == 2 ) {
+ len |= c;
+ } else if ( index == 3 ) {
+ if ( c != 3 ) {
+ wifiReadEnd();
+ return -3;
+ }
+ } else if ( index == 4 ) {
+ len |= c << 8;
+ } else if ( index & 1 ) {
+ buff[(index - 5)/2] = c << 4;
+ } else {
+ buff[(index - 5)/2] |= c;
+ }
+ index++;
+ }
+ wifiReadEnd();
+ return len;
+ }
+
+public:
+ WiFiScanner()
+ {
+ sequence = 0;
+ }
+
+ void reset()
+ {
+ wifi.baud(BAUD_RATE);
+ wifi.format(8, Serial::None, 1);
+
+ sequence = 0;
+ PRST = 0; // reset BP3591
+ wait(1.0); // perhaps needs 1 sec
+ PRST = 1;
+ UART_CTS = 1;
+ }
+
+ void serialInit()
+ {
+ int i;
+ int c = 0;
+
+ wifiReadWait();
+ while (true) {
+ if (wifi.writeable())
+ wifiPutc('A');
+ if (wifi.readable()) {
+ if ( c == '*' ) {
+ c = wifiGetc();
+ if ( c == CR ) {
+ break;
+ }
+ } else {
+ c = wifiGetc();
+ }
+ }
+ wait(SHORT_WAIT); // this wait is important
+ }
+
+ while (wifi.readable())
+ wifiGetc();
+ for ( i = 0; i < 8; i++ ) {
+ delayedPutc(0xf1);
+ }
+ c = 0;
+ while (true) {
+ if (wifi.readable()) {
+ if ( c == '*' ) {
+ c = wifiGetc();
+ if ( c == CR ) {
+ break;
+ }
+ } else {
+ c = wifiGetc();
+ }
+ }
+ }
+ wifiReadEnd();
+ }
+
+ void waitStartup()
+ {
+ int i;
+ int len = 0;
+ bool loopFlag = true;
+ for (i = 0; loopFlag || len <= 0 || wifi.readable(); i++) {
+ len = wifiRead();
+ if ( len == 8 && buff[5] == 0x00 && buff[4] == 0x3d) {
+ loopFlag = false;
+ }
+ lcd.putc('+');
+ }
+ }
+
+ void scanMode()
+ {
+ // WID_SSID
+ unsigned char cmd0[] = { 0x57, 0x00, 0x08, 0x00, 0x00, 0x30, 0x01, 0x00 };
+ wifiWrite(cmd0);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_BSS_TYPE
+ unsigned char cmd1[] = { 0x57, 0x00, 0x08, 0x00, 0x00, 0x00, 0x01, 0x00 };
+ wifiWrite(cmd1);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_BCAST_SSID
+ unsigned char cmd2[] = { 0x57, 0x00, 0x08, 0x00, 0x15, 0x00, 0x01, 0x01 };
+ wifiWrite(cmd2);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_SCAN_TYPE
+#ifdef PASSIVE_SCAN
+ unsigned char cmd3[] = { 0x57, 0x00, 0x08, 0x00, 0x07, 0x00, 0x01, 0x00 };
+#else
+ unsigned char cmd3[] = { 0x57, 0x00, 0x08, 0x00, 0x07, 0x00, 0x01, 0x01 };
+#endif
+ wifiWrite(cmd3);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_ENABLE_CHANNEL
+ unsigned char cmd4[] = { 0x57, 0x02, 0x0b, 0x00, 0x24, 0x20, 0x04, 0xff, 0x1f, 0x00, 0x00 };
+ wifiWrite(cmd4);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_SITE_SURVEY
+#ifdef MULTI_CHANNEL
+ unsigned char cmd5[] = { 0x57, 0x01, 0x08, 0x00, 0x0e, 0x00, 0x01, 0x11 };
+#else
+ unsigned char cmd5[] = { 0x57, 0x01, 0x08, 0x00, 0x0e, 0x00, 0x01, 0x01 };
+#endif
+ wifiWrite(cmd5);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+ // WID_SCAN_FILTER
+#ifdef MULTI_CHANNEL
+ unsigned char cmd6[] = { 0x57, 0x02, 0x08, 0x00, 0x36, 0x00, 0x01, 0x00 };
+#else
+ unsigned char cmd6[] = { 0x57, 0x02, 0x08, 0x00, 0x36, 0x00, 0x01, 0x00 };
+#endif
+ wifiWrite(cmd6);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+#ifdef PASSIVE_SCAN
+ // WID_SITE_SURVEY_SCAN_TIME
+ unsigned char cmd7[] = { 0x57, 0x00, 0x09, 0x00, 0x0e, 0x10, 0x02, 0x00, 0x02 };
+ wifiWrite(cmd7);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+#endif
+ }
+
+ void doScan()
+ {
+ int i, len, channel;
+ int count, write_index;
+
+ apinfo_count = 0;
+ for (channel = 0; channel < TOTAL_CHANNELS; channel++ ) {
+ myled1 = (channel >> 3) & 1;
+ myled2 = (channel >> 2) & 1;
+ myled3 = (channel >> 1) & 1;
+ myled4 = channel & 1;
+
+ // WID_CURRENT_CHANNEL
+#ifdef MULTI_CHANNEL
+ unsigned char cmd8[] = { 0x57, 0x02, 0x08, 0x00, 0x02, 0x00, 0x01, 0x10 };
+ cmd8[7] = channel + 1; // 1 origin
+ wifiWrite(cmd8);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+#endif
+ // WID_START_SCAN_REQ
+ unsigned char cmd9[] = { 0x57, 0x02, 0x08, 0x00, 0x1e, 0x00, 0x01, 0x01 };
+ wifiWrite(cmd9);
+ while ( wifiRead() <= 0 || (buff[5] != 0x00 || buff[4] != 0x05 || buff[7] != 1))
+ wait(SHORT_WAIT);
+
+#ifdef PASSIVE_SCAN
+ wait(0.5);
+#else
+ wait(0.02);
+#endif
+
+ // WID_SITE_SURVER_RESULTS
+ unsigned char cmd10[] = { 0x51, 0x03, 0x06, 0x00, 0x12, 0x30 };
+ wifiWrite(cmd10);
+ while ( (len = wifiRead()) <= 0 || (buff[5] != 0x30 || buff[4] != 0x12))
+ wait(SHORT_WAIT);
+ if ( len < 10 ) {
+ continue;
+ }
+ count = (buff[7] - 2) / 44;
+ for ( i = 0; i < count; i++ ) {
+ for ( write_index = 0; write_index < apinfo_count; write_index++) {
+ if ( memcmp(apinfos[write_index].essid, buff + (9 + i *44), 33) == 0 &&
+ memcmp(apinfos[write_index].bssid, buff + (9 + i * 44 + 36), 6) == 0 ) {
+ break; // already recorded
+ }
+ }
+ if ( write_index == apinfo_count ) {
+ memcpy(apinfos[write_index].essid, buff + (9 + i * 44), 33);
+ memcpy(apinfos[write_index].bssid, buff + (9 + i * 44 + 36), 6);
+ apinfos[write_index].power = (signed char)buff[9 + i * 44 + 42];
+ apinfo_count++;
+ } else if ( apinfos[write_index].power < (signed char)buff[9 + i * 44 + 42] ) {
+ apinfos[write_index].power = (signed char)buff[9 + i * 44 + 42];
+ }
+ }
+ }
+ }
+};
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