Slow WiFi Scan

[mrrosen]

I updated an old project from an older version of the ESP IDF (I think before v2.1; but unclear as the git history has been erased...) to IDFv3.1. I noticed that on the old IDF, I was able to do an active WiFi scan in about 1 sec (time between call to esp_wifi_start_scan() to SYSTEM_EVENT_SCAN_DONE). However, when I moved to the new IDF, its taking about 2 sec; even though it shouldnt take more than 500 ms with the settings Im using. I have set the wifi_scan_config_t as follows:

Code: Select all

wifi_scan_config_t scan_config = {
            .ssid = NULL,
            .bssid = NULL,
            .show_hidden = false,
            .channel = 0,
            .scan_type = WIFI_SCAN_TYPE_ACTIVE };
scan_config.scan_time.active.min = 40;
scan_config.scan_time.active.max = 40;

I have also set the country to try to minimize the number of channels scanned:

Code: Select all

wifi_country_t wifi_country = {
        .cc = {'U', 'S', '\0'},
        .schan = 1,
        .nchan = 11
};
esp_wifi_set_country(&wifi_country);

I modified the wifi/iperf example to also use these settings and am getting the same result; though I do notice that if the module is not connected to a wifi network, the scan time is only 1.5 sec while when connected to an AP, its about the same 2 sec. Is there a way to actually get quicker scans?

[tommeyers]

Yes, multiple scanner hardware and divide-up the work.

Not intended to be a blunt/impolite reply. It is a method actually used by MIT Sensable Cities Lab (my son is the researcher doing that).

Tom Meyers

[mrrosen]

While thats a thought, its not practical in our case. Im more wondering why ESP32 is taking 200%-300% the time of the scan (should be ~440ms @ 11ch,40ms/ch, but is taking ~2000ms with connection to complete; I can understand some overhead but this much?) before coming back with a scan complete message and if anything can be done to fix that long delay.

[tommeyers]

here is my scanner that worked OK, supporting files attached:

Code: Select all

#include <WiFi.h>
#include <WiFiClient.h>
#include <WiFiServer.h>
#include "./functions.h"

#define disable 0
#define enable  1
#define ACTIVITYLED 13         // GPIO13/D7
#define SWITCHPIN 0            // GPIO00/D3
unsigned int channel = 1; 
const char *ssid = "ORANGE-Tom";
const char *password = "xyzzy3585";
IPAddress ip(192, 168, 1, 254);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);
WiFiServer webServer (80);
char mode;                     //s - sniff, h - html
int currentSwitchState;        // the current reading from the switch pin
int lastSwitchState = LOW;     // the previous reading from the switch pin
//=========================================================================================================================
void setup() {
  Serial.begin(57600);
  delay(100);
  ////////////////Temporary//////////////////////////////
  { uint8_t whoStation[] = {0xD4,0xCA,0x94,0x8D,0xC3,0x6A}; // E0-CA-94-8D-C3-6A
    uint8_t whoName[] = {'B','i','k','k','e','y','-','P','C',' ',' ',' ',' ',' ',' '}; 
    registerWho(whoStation, whoName);
  }
  { uint8_t whoStation[] = {0x5c,0xcf,0x7f,0x81,0x05,0x96}; 
    uint8_t whoName[] = {'T','o','m','-','e','s','p','8','2','6','6','S','N','I','F'}; 
    registerWho(whoStation, whoName);
  }
  { uint8_t whoStation[] = {0xd4,0x7b,0xb0,0x77,0xe5,0x73}; 
    uint8_t whoName[] = {'0','0','0','-','e','s','p','8','2','6','6','S','N','I','F'}; 
    registerWho(whoStation, whoName);
  }
  ////////////End Temporary//////////////////////////////
  pinMode(SWITCHPIN, INPUT);
  pinMode(SWITCHPIN, INPUT);
  if (switchState() == 1) {
      disableSnifferEnableWebServer ();
  } else {
      disableWebServerEnableSniffer ();
  }
  Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
  Serial.printf("\n\nSDK version:%s\n\r", system_get_sdk_version());
  Serial.println(F("------------------------------------------Activity-(c - Clients, b - Beacons, w = who-------------------------"));
  Serial.println(F("/Type:/ /-------MAC------/Dir/ /----WiFi Access Point SSID-----/ /-------MAC------/  Chnl  RSSI  /----Who--------/"));
  pinMode(ACTIVITYLED, OUTPUT); //Declare GPIO13/D7 as output
}
//=========================================================================================================================
void disableSnifferEnableWebServer () {
  mode = 'h';
  // Sniffer - Disable
  wifi_promiscuous_enable(disable);
  // Web Server - Enable
  Serial.println("");
  webServer.on ( "/", handleRoot );
  webServer.on ( "/clients", handleClients );
  webServer.on ( "/beacons", handleBeacons );
  webServer.on ( "/who", handleWho );
  webServer.on ( "/deletewho", handleDeleteWho);
  webServer.begin();
  WiFi.config(ip, gateway,subnet);
  WiFi.begin ( ssid, password );
  while ( WiFi.status() != WL_CONNECTED ) {
    delay (500);
    Serial.print ( "." );
  }  
  Serial.print ( "HTTP server started with" );
  uint8_t macaddr[6];   
  wifi_get_macaddr(0x00, macaddr);
  Serial.printf("\nMAC: %02x:%02x:%02x:%02x:%02x:%02x\r\n", macaddr[0],macaddr[1], macaddr[2], macaddr[3], macaddr[4], macaddr[5]);
  Serial.println ("");
}
//=========================================================================================================================
void disableWebServerEnableSniffer () {
  mode = 's';
  // Web Server - Disable
  ///////////////////////////////////////////////webServer.stop();
  // Sniffer - Enable
  Serial.println("");
  wifi_set_opmode(STATION_MODE);            // Promiscuous works only with station mode
  wifi_promiscuous_enable(disable);
  wifi_set_promiscuous_rx_cb(promisc_cb);   // Set up promiscuous callback
  wifi_promiscuous_enable(enable);
}
//=========================================================================================================================
int switchState () {
  unsigned long debounceDelay = 50;     // the debounce time
  unsigned long lastDebounceTime = 0;   // the last time the output pin was toggled
  int reading = digitalRead(SWITCHPIN); // read the state of the switch
  if (reading != lastSwitchState) {     // If the switch changed, due to noise or pressing:
    lastDebounceTime = millis();        // reset the debouncing timer
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
      currentSwitchState = reading;
  }
  lastSwitchState = reading;  // save the reading. Next time through the loop, it'll be the lastButtonState:
  return currentSwitchState;
}
//=========================================================================================================================
void loop() {
  char commandChar = ' ';    
  if (mode == 's' and switchState() == 1) {
      disableSnifferEnableWebServer ();
  } else if (mode == 'h' and switchState() == 0) {
      disableWebServerEnableSniffer ();
  }
  Serial.print(mode);
  webServer.handleClient(); 
  delay(1000);
  unsigned int saveChannel = wifi_get_channel();
  channel = 0;
  if (mode == 's') {
    wifi_set_channel(channel);
    while (channel < 14) { 
      if (foundOne == 'y') {
        foundOne = 'n';
        blink();
      }
      channel++;
      if (mode == 's') {
        wifi_set_channel(channel);
        delay(100);  // critical processing timeslice for NON-OS SDK (non-OS vs RTOS)! No delay(0) yield()
      }
      if (Serial.available() > 0) {
        commandChar = Serial.read();
        while (Serial.available()) {
          Serial.read();
        }
      }  
      if (commandChar == 'c') { // List Clients
        Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
        Serial.println(F("----------------------------------------Clients-------------------------------------------------------------"));
        Serial.println(F("/Type:/ /-------MAC------/Dir/ /----WiFi Access Point SSID-----/ /-------MAC------/  Chnl  RSSI  /----Who--------/"));
        for (int u = 0; u < clientsKnownCount; u++) printClient(clientsKnown[u]);   
        Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
      }
      if (commandChar == 'b') { // List Beacons
        Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
        Serial.println(F("----------------------------------------Beacons-------------------------------------------------------------"));
        Serial.println(F("/Type:/                   /Dir//----WiFi Access Point SSID------/  /------MAC------/  Chnl  RSSI") );
        for (int u = 0; u < apsKnownCount; u++) printBeacon(apsKnown[u]);
        Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
      }
      if (commandChar == 'w') { // List who
        Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
        Serial.println(F("-------------------------------------------Who--------------------------------------------------------------"));
        Serial.println(F("/-------Who-----/ /-----MAC-------/"));
        for (int u = 0; u < whosCount; u++) printWho(whosKnown[u]);
        Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
      }
      if (commandChar == 's') { // Sniffer
        disableWebServerEnableSniffer();
      }
      if (commandChar == 'h') { // HTML
        disableSnifferEnableWebServer();
      }
    }
  }
  if (Serial.available() > 0) {
    commandChar = Serial.read();
    while (Serial.available()) {
      Serial.read();
    }
  }  
  if (commandChar == 'c') { // List Clients
    Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
    Serial.println(F("----------------------------------------Clients-------------------------------------------------------------"));
    Serial.println(F("/Type:/ /-------MAC------/Dir/ /----WiFi Access Point SSID-----/ /-------MAC------/  Chnl  RSSI  /----Who--------/"));
    for (int u = 0; u < clientsKnownCount; u++) printClient(clientsKnown[u]);   
    Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
  }
  if (commandChar == 'b') { // List Beacons
    Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
    Serial.println(F("----------------------------------------Beacons-------------------------------------------------------------"));
    Serial.println(F("/Type:/                   /Dir//----WiFi Access Point SSID------/  /------MAC------/  Chnl  RSSI") );
    for (int u = 0; u < apsKnownCount; u++) printBeacon(apsKnown[u]);
    Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
  }
  if (commandChar == 'w') { // List who
    Serial.println(F("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"));
    Serial.println(F("-------------------------------------------Who--------------------------------------------------------------"));
    Serial.println(F("/-------Who-----/ /-----MAC-------/"));
    for (int u = 0; u < whosCount; u++) printWho(whosKnown[u]);
    Serial.println(F("--------------------------------Activity-(c - Clients, b - Beacons, w = who)-----------------"));
  }
  if (commandChar == 's') { // Sniffer
    disableWebServerEnableSniffer();
  }
  if (commandChar == 'h') { // HTML
    disableSnifferEnableWebServer();
  }
  
  if(mode == 'h') {
     wifi_set_channel(saveChannel);
  }
}
//=========================================================================================================================
void handleRoot() {
  Serial.println("\n-------------------------------------------------------handleRoot");
  htmlReply("home");
}
//=========================================================================================================================
void handleClients() {
    Serial.println("\n-------------------------------------------------------handleClients");
  htmlReply("clients");
}
//=========================================================================================================================
void handleBeacons() {
    Serial.println("\n-------------------------------------------------------handleBeacons");
  htmlReply("beacons");
}
//=========================================================================================================================
void handleWho() {
  Serial.println("\n-------------------------------------------------------handleWho");
  htmlReply("who");
}
void handleDeleteWho() {
  int sequence;
  Serial.println("\n-------------------------------------------------------handleDeleteWho");
  if (webServer.arg("Sequence") != "" &&+ webServer.arg("Sequence").toInt() != 0) {
    sequence = webServer.arg("Sequence").toInt();
    if (sequence <= whosCount) {
      for (int i = sequence - 1;i < whosCount; i++) {
        whosKnown[i] = whosKnown[i + 1];
      }
      whosCount = whosCount - 1;
    }
  }  
  htmlReply("who");
}
//=========================================================================================================================
void handleWhoAdd() {
    Serial.println("\n-------------------------------------------------------handleWhoAdd");
  htmlReply("who");
}
//=========================================================================================================================
void htmlReply(String type) {  
  ///************************************
  int hrSinceBoot;
  int minSinceBoot;
  int secSinceBoot;
  String x  = "<html>\n";                                                                  //---------------------------------Common
         x = x 
         + "<head width=100% align=center>\n"
            //+ "<meta http-equiv='refresh' content='5;url=/'/>\n"
            + "<title width=100% align=center>ESP8266 - Sniffer Data Access</title>\n"
            + "<style>\n"
              + "body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }\n"
            + "</style>\n"
         + "</head>\n"
         + "<body width=100%>\n"
            + "<style>\n"
               + " section {\n"
               + "background: white;\n"
               + "color: black;\n"
                  + "border-radius: 1em;\n"
                  + "padding: 1em;\n"
                  + "position: absolute;\n"
                  + "top: 50%;\n"
                  + "left: 50%;\n"
                  + "margin-right: -50%;\n"
                  + "transform: translate(-50%, -50%) }\n"
                  + "table {align:center}\n"
                  + "table, th, td {border: 1px solid black;border-collapse: collapse;}\n"
                  + "th, td {padding: 1px;text-align: center;}\n"
            + "</style>\n"
            + "<h1 align:center width=100%><p>ArduinoEPS8266 - WiFi Sniffer</p></h1>\n"
            + "<div style=\"width: 725px;\">\n"
              + "<table style=\"width: 725px; table-layout: fixed;\">\n"
                + "<tr style=\"width: 725px;\">\n"
                  + "<table style=\"width: 725px; table-layout: fixed;\">\n"
                          + "<tr>\n"
                                  + "<td width=25%> <form name='onForm' action='/who'   method='post'>\n"
                                    + "<div align='center'>\n"
                                    + "<br><input type='submit' value='Who' style=\"width: 70px; height: 25px; background-color: #00FF00; color: #FFFFFF; font-weight: bold;\"><br>\n"
                                    + "</div>\n"
                                    + "</form>\n"
                                  + "</td>\n"
                                  + "<td width=25%> <form name='onForm' action='/clients'   method='post'>\n"
                                    + "<div align='center'>\n"
                                    + "<br><input type='submit' value='Clients' style=\"width: 70px; height: 25px; background-color: #00FF00; color: #FFFFFF; font-weight: bold;\"><br>\n"
                                    + "</div>\n"
                                    + "</form>\n"
                                  + "</td>\n"
                                  + "<td width=25%> <form name='onForm' action='/beacons'   method='post'>\n"
                                    + "<div align='center'>\n"
                                    + "<br><input type='submit' value='Beacons' style=\"width: 70px; height: 25px; background-color: #00FF00; color: #FFFFFF; font-weight: bold;\"><br>\n"
                                    + "</div>\n"
                                    + "</form>\n"
                                  + "</td>\n"
                                  + "<td width=25%> <form name='onForm' action='/'   method='post'>\n"
                                    + "<div align='center'>\n"
                                    + "<br><input type='submit' value='Home' style=\"width: 70px; height: 25px; background-color: #00FF00; color: #FFFFFF; font-weight: bold;\"><br>\n"
                                    + "</div>\n"
                                    + "</form>\n"
                                  + "</td>\n"
                          + "</tr>\n"
                  + "</table>\n"
                + "</tr>\n"
                + "<tr>\n";
                              if (type == "home") {                                  //---------------------------------home
                                x = x + "<br><br>";     
                                x = x + "<table style=\"width: 725px; table-layout: fixed;\">\n";
                                  x = x + "<thead>\n";
                                          x = x + "<tr>"
                                                +   "<td><p style=\"font-weight:bold\"> Notes on Use</p></td>"
                                                + "</tr>";
                                  x = x + "</thead>";
                                  x = x + "<tbody>\n";
                                         x =  x + "<tr>"
                                                +   "<td>"
                                                +   "<font  size=\"2\">"
                                                +   "<p> by Tom Meyers November 2017 Santiago DR</p>"
                                                +   "</font>"
                                                +   "</td>"
                                                + "</tr>";
                                  x = x + "</tbody>\n";
                                x = x + "</table>"; 
                                x = x + "<div style=\"width:725px; height:50px; overflow: auto;\" >\n"
                                      + "Example of using div for scrolling"           
                                      + "text text (Description of sniffer) text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "text text text text text text text text text "
                                      + "</div>\n";
                              }
                              if (type == "who") {                 //---------------------------------Who
                                x = x + "<br><br>";     
                                x = x + "<table style=\"width: 725px; table-layout: fixed;\">\n";
                                      x = x + "<thead>\n";
                                            x = x + "<tr><th> Who do I know </th></tr>"
                                            + "</thead>\n"
                                            + "</table>";
                                x = x + "<table style=\"width: 725px; table-layout: fixed;\">\n";
                                      x = x + "<thead>\n";
                                            x = x + "<tr>"
                                              + "<th>Sequence</th>"
                                              + "<th>Name</th>"
                                              + "<th>MAC</th>"
                                            + "</tr>";
                                      x = x + "</thead>";
                                      x = x + "<tbody>\n";   
                                         for (int i = 0; i < whosCount  ; i++) {    
                                                     x = x 
                                                     + "<tr>\n"
                                                        + "<td>"
                                                           + (i + 1)
                                                        + "</td>"
                                                        + "<td>";
                                                         for (int j = 0; j < 15 ; j++) {
                                                           x = x + (char) whosKnown[i].whoName[0];
                                                         }  
                                                       x = x
                                                         + "</td>"
                                                         + "<td>"
                                                           + macToString(whosKnown[i].whoStation)
                                                       + "</td>" 
                                                     + "</tr>\n";
                                          }
                                       x = x + "</tbody>\n";
                                 x = x + "</table><br><br> \n";
                                 x = x + "<table style=\"width: 725px;\"><tbody>";
                                       x = x + "<tr colspan=\"2\"><td>"
                                          + "<form action=\"/deletewho\">"
                                            + "&nbsp;&nbsp;Sequence: <input type=\"text\" name=\"Sequence\" pattern=\"[0-9]+\" title=\"Sequence Number\">"
                                            + "&nbsp;&nbsp;&nbsp;&nbsp;<input name=\"Delete\" type=\"submit\" value=\"Delete\">"
                                          + "</form>" 
                                       + "<td></tr>\n";
                                       x = x + "<tr colspan=\"2\"><td>"
                                          + "<form action=\"/addwho\">"
                                            + "MAC:&nbsp;&nbsp;<input type=\"text\" name=\"MAC\" pattern=\"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$\" title=\"XX:XX:XX:XX:XX:XX\">"
                                            + "&nbsp;&nbsp;&nbsp;Name:&nbsp;&nbsp;<input type=\"text\" name=\"Name\"  title=\"Descripive Name\">"
                                            + "&nbsp;&nbsp;&nbsp;&nbsp;<input name = \"Add\" type=\"submit\">"
                                          + "</form>"
                                       + "<td></tr>\n";
                                x = x + "</tbody></table>";
                              } 
                              /*  
                               *      uint8_t bssid[ETH_MAC_LEN];
                                      uint8_t bssidWhoName[15];                   // who this is from table of known whos
                                      uint8_t station[ETH_MAC_LEN];
                                      uint8_t StationWhoName[15];                   // who this is from table of known whos
                                      uint8_t ap[ETH_MAC_LEN];
                                      uint8_t apWhoName[15];                   // who this is from table of known whos
                                      int channel;
                                      int err;
                                      signed rssi;
                                      uint16_t seq_n;


                               */
                              if (type == "clients") {                                   //---------------------------------Client
                                updateClientNames();
                                x = x + "<br><br>";     
                                x = x + "<table style=\"width: 725px; table-layout: fixed;\">\n";
                                      x = x + "<thead>\n";
                                            x = x + "<tr><th> Clients Found </th></tr>";
                                      x = x + "</thead>";
                                      x = x + "</table>";      
                                      x = x + "<table style=\"width: 725px; table-layout: fixed;font-size:10px\">\n";
                                      x = x + "<thead>\n";
                                           x = x + "<tr>"
                                              + "<th>Name</th>"
                                              + "<th>bssid</th>"
                                              + "<th>Station</th>"
                                              + "<th>AP</th>"
                                              + "<th>Channel</th>"
                                              + "<th>err</th>"
                                              + "<th>rssi</th>"
                                              + "<th>SEQ_N</th>"
                                            + "</tr>";
                                      x = x + "</thead>";
                                      x = x + "<tbody>\n";   
                                         for (int i = 0; i < clientsKnownCount  ; i++) {    
                                                     x = x 
                                                     + "<tr>\n"
                                                       + "<td>";   //Name
                                                         for (int j = 0; j < 10 ; j++) {
                                                           x = x + "*";                  /////////////////////// x = x + (char) clientsKnown[i].whoName[0];
                                                         }  
                                                       x = x
                                                         + "</td>" 
                                                         + "<td>"   //bssid
                                                           + macToString(clientsKnown[i].bssid)
                                                           + "<br>" + clientsKnown[i].bssidWhoName[0]
                                                       + "</td>" 
                                                       + "<td>"     //Station
                                                             + macToString(clientsKnown[i].station)
                                                       + "</td>"
                                                       + "<td>"     //AP
                                                             + macToString(clientsKnown[i].ap)
                                                       + "</td>"
                                                       //////////////////////////////////////
                                                       + "<td>"     //Channel
                                                             + clientsKnown[i].channel
                                                       + "</td>"
                                                       + "<td>"     //err
                                                             + clientsKnown[i].err
                                                       + "</td>"
                                                       + "<td>"     //rssi
                                                             + clientsKnown[i].rssi
                                                       + "</td>"
                                                       + "<td>"     //SEQ_N
                                                             + clientsKnown[i].seq_n
                                                       + "</td>"
                                                     + "</tr>\n";
                                          }
                                       x = x + "</tbody>\n";
                                 x = x + "</table> \n"; 
                              }
                              ///*
                               /* beaconInfo apsKnown[MAX_APS_TRACKED];                    // Array to save MACs of known APs
                                 int apsKnownCount = 0;                                     // Number of known APs

                                      struct beaconInfo {
                                        uint8_t bssid[ETH_MAC_LEN];
                                        uint8_t ssid[33];
                                        int ssid_len;
                                        int channel;
                                        int err;
                                        signed rssi;
                                        uint8_t capa[2];
                                      };
                              //*/
                              if (type == "beacons") {                                    //---------------------------------Beacon
                                x = x + "<br><br>";     
                                x = x + "<table style=\"width: 725px; table-layout: fixed;\">\n";
                                      x = x + "<thead>\n";
                                            x = x + "<tr><th>Beacons Found </th></tr>";
                                            x = x + "</thead>  </table>";
                                x = x + "<table style=\"width: 725px; table-layout: fixed;font-size:10px\">\n";
                                            x = x + "<tr>"
                                              + "<th>bssid</th>"
                                              + "<th>ssid</th>"
                                              + "<th>ssid_len</th>"
                                              + "<th>Channel</th>"
                                              + "<th>err</th>"
                                              + "<th>rssi</th>"
                                              + "<th>capa[0] capa[1]</th>"
                                            + "</tr>";
                                      x = x + "</thead>";
                                      x = x + "<tbody>\n";   
                                         for (int i = 0; i < apsKnownCount  ; i++) {    
                                                     x = x 
                                                     + "<tr>\n"
                                                        + "<td>"
                                                          + macToString(apsKnown[i].bssid)
                                                        + "</td>"
                                                      + "<td>";
                                                         for (int j = 0; j < apsKnown[i].ssid_len ; j++) {
                                                           x = x + (char) apsKnown[i].ssid[0];
                                                         }  
                                                       x = x
                                                        + "<td>"
                                                          + apsKnown[i].ssid_len
                                                        + "</td>"
                                                         + "<td>"
                                                             + apsKnown[i].channel
                                                         + "</td>"
                                                         
                                                       + "<td>"
                                                           + apsKnown[i].err
                                                       + "</td>"
                                                       + "<td>"
                                                           + apsKnown[i].rssi
                                                       + "</td>"
                                                       + "<td>"
                                                           + apsKnown[i].capa[0] 
                                                           + "/"
                                                           + apsKnown[i].capa[0]
                                                       + "</td>"
                                                     + "</tr>\n";
                                          }
                                       x = x + "</tbody>\n";
                                 x = x + "</table> \n";
                              }
            x = x   + "</tr>"
                    + "</table>\n"
                    + "</div>\n"
         + "</body>\n"                                                            //---------------------------------More Common
      + "</html>\n";
    //  hrSinceBoot, minSinceBoot, secSinceBoot, hrSinceOn, minSinceOn, secSinceOn, hrSinceOff, minSinceOff, secSinceOff );
  webServer.send ( 200, "text/html", x);
  //************************************************************************/
}
//=========================================================================================================================
void blink() {
  digitalWrite(13, HIGH);      // turn the LED on 
  delay(1000);                         // Wait 1 second 
  digitalWrite(13, LOW);       // turn the LED off 
  delay(1000);                        // wait 1 second
}
//=========================================================================================================================
String macToString(uint8_t MAC[ETH_MAC_LEN]) {
  String formatedMAC;
  formatedMAC = "";
  
  for (int i = 0; i < ETH_MAC_LEN; i++) {
      if ( i == ETH_MAC_LEN - 1) {
        formatedMAC = formatedMAC + format("%02x", MAC[i]);
      } else {
        formatedMAC = formatedMAC + format("%02x:", MAC[i]);
      }
  }
  return formatedMAC;
}
//=========================================================================================================================
String xformat(char formatString[], int formatData){  // hold-----------------
  char charFormatted[100];
  sprintf(charFormatted, formatString, formatData);
  return (String) charFormatted;
}
//=========================================================================================================================
String format(char formatString[], char formatData){  // format a single char
  char charFormatted[100];
  sprintf(charFormatted, formatString,  formatData);
  return (String) charFormatted;
}
//clientInfo clientsKnown[MAX_CLIENTS_TRACKED];            // Array to save MACs of known CLIENTs
//int clientsKnownCount = 0;                                 // Number of known CLIENTs
//whoInfo whosKnown[MAX_KNOWN_TRACKED];                            // Identified MAC addresses 
//int whosCount = 0;

void updateClientNames() {
    for (int i = 0; i < clientsKnownCount; i++) {
        for(int j = 0; j < whosCount; j++) {
          Serial.println(macToString(clientsKnown[i].bssid) + "/"+ macToString(whosKnown[i].whoStation));

          if(memcmp(clientsKnown[i].station,whosKnown[j].whoStation,ETH_MAC_LEN)) {
                Serial.println("equal station");
                for(int k = 0; k < 15;k++) {clientsKnown[i].stationWhoName[k] = whosKnown[i].whoName[k];}    
          }
          if(memcmp(clientsKnown[i].bssid,whosKnown[j].whoStation,ETH_MAC_LEN)) {
                Serial.println("equal bssid");
                for(int k = 0; k < 15;k++) {clientsKnown[i].bssidWhoName[k] = whosKnown[i].whoName[k];}    
          }
          if(memcmp(clientsKnown[i].ap,whosKnown[j].whoStation,ETH_MAC_LEN)) {
                Serial.println("equal ap");
                for(int k = 0; k < 15;k++) {clientsKnown[i].apWhoName[k] = whosKnown[i].whoName[k];}    
          }
        }
    }
}

[mrrosen]

Im working on ESP32 with the ESP IDF; this appears to be code for ESP8266 Arduino.

[tommeyers]

I intended to supply an example of similar working code. Not so much the individual functtion calls but structure; e.g. cycling through the channels, ...

Tom Meyers

[mrrosen]

Sorry for any misunderstanding, but I do need an active scan to save time and am not sure if its possible to manually send probe requests while in promiscuous mode (though maybe, Im not sure). Still, I rather clear up the overhead from the builtin scan functions if possible before attempting that.

[mrrosen]

Something thats also strange is that if I set the channel parameter and run through all 11 channels by calling esp_wifi_scan_start 11 times, it works as expected; taking only about 540ms in the log (no longer than 600ms) to complete and this is with print statements between each scan (I also setup these prints to write to flash, so they add some minor delay as well). I am rather confused as to why it seems to be x4 slower if I set the channel to 0 than if I manually loop through all the channels.