This is a forked version of ESP32's bundled DNSServer. Unlike bundled version based on WiFiUDP lib this fork was rewritten to use AsyncUDP lib and is more efficient on using CPU/mem resources.
A PR espressif/arduino-esp32#7482 has been raised for the upstream. Untill(unless) it accepted this repo will be a test-lab for developing. Feel free to use this lib to replace bundled ESP32's DNSServer.
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Bundled implementation of DNSServer lib for ESP32 uses WiFiUDP which is not very efficient considering cpu/mem resources. It hooks to loop() for packet processing doing useless malloc's/free each run cycle, even when no requests are received.
https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFi/src/WiFiUdp.cpp#L205-L221
int WiFiUDP::parsePacket(){
// skipped
char * buf = new char[1460];
if ((len = recvfrom(udp_server, buf, 1460, MSG_DONTWAIT, (struct sockaddr *) &si_other, (socklen_t *)&slen)) == -1){
delete[] buf;
return 0;
}This PR offers refactored DNSServer code based on bundled AsyncUDP lib along with other optimizations and enhansments.
- got rid of intermediate mem buffers and extra data copies in DNSServer code
- added sanity checks for mem bounds
- optimize label/packet length calculations
- removed some dynamically allocated members
- refactored "Captive Portal" example, now it will display portal detection pop-up on Android, Windows, etc...
- other code cleanup
Other known issues:
- non A req's ain't handled properly, i.e. always reply with A type records
- pkts with edns opt ain't handled properly, packets ignored due to additional RR's>1