Turn-off Broadcast/Multicast

[mcr-ksh]

• Hardware: ESP8266
• Core Version: 2.7.2
• Development Env: Arduino IDE
• Operating System: MacOS

Settings in IDE

• Module: Wemos D1 R2 & mini
• Flash Mode: no idea
• Flash Size: 4MB/1MB
• lwip Variant: v2 Lower Memory
• Reset Method: ck
• Flash Frequency: 40Mhz
• CPU Frequency: 80Mhz
• Upload Using: OTA & SERIAL
• Upload Speed: 115200 & 921600

Problem Description

Our production FW is running with almost no memory left and we experience part of our buffers overwritten by multicast packets, or at least the an old pointer is pointing to a memory region which is then filled by multicast packets (SSDP).

We would like to circumvent receiving buffers and information (like multicast/broadcast) that are not essential to us.

Is there a way to turn off the broadcat/multicast reception on the IP stack?

[d-a-v]

One solution is to get more 16KB RAM. And that's possible for free thanks to #7060 and later that are merged in current git master.
If you can, use lwIP "lower bandwidth" flavour which reserves less memory for TCP packets.

AFAIK we can't "disable" receiving *cast packets. They are packets like others and need anyway to be received and analyzed before getting dropped (after checking that we are not interested)
That said, your data should never be overridden by these packets. Space for them is allocated. They are dropped before analyze when space for their reception cannot be allocated.
You may double check that your data are pointing to still valid allocated space which otherwise could be allocated for other purpose.

To help debugging the software part of your project, you can also use emulation on host in tests/host. The network part works well and debugging tools like valgrind can help finding bugs.

[mcr-ksh]

Hi d-a-v, thanks for the hint. I guess I have to wait for the official release then to get more RAM before we can consider going live.
Regarding the LwIP, we have the "lower bandwidth" flavour already in use.

Is there a chance to send us a link to the emulation? I haven't heard of that yet.

[d-a-v]

I guess I have to wait for the official release then to get more RAM before we can consider going live.

You may have a try with current git master version, or stage version with PlatformIO, or the snapshot release with Arduino IDE.
We welcome all testers so we can fix issues before the official release.

Is there a chance to send us a link to the emulation? I haven't heard of that yet.

Yes, here it is.

Here's the updated README, result of the make command issued from that directory.

Host Tests for Continuous Integration
-------------------------------------

	make FORCE32=0 OPTZ=-O0 CI

	(FORCE32=0: https://bugs.launchpad.net/ubuntu/+source/valgrind/+bug/948004)

Sketch emulation on host
------------------------

This environment let compile esp8266/Arduino sketches into native
environment.  Network (tcp, udp, including ssl and multicast) is linked to
local host interfaces.  WiFi is trivially emulated and reported as "just"
already connected and usable.

Currently network emulation is a complete rewrite of
WiFiClient+WiFiServer/ClientContext and WifiUdp/UdpContext using socket
posix API.  Further work will optionally propose native lwIP library
instead.

Serial UART0 and UART1 are emulated via stdin/stdout/stderr.  Therefor
stdin is connected to UART0(RX) and stdout is connected to UART0(TX).
UART1(TX) writes to stderr.  Reading from stdin happens in non-blocking
raw mode, that means each character is directly injected into the UART
FIFO without any buffering in the console.  The command line switch -c
can be used to stop the emulation from intercepting CTRL-C (SIGINT).

How to compile and run a sketch
-------------------------------

All results are stored in ./bin/ .

Show the core example list:
	make list


Build one example
	make D=1 ../../libraries/esp8266/examples/Blink/Blink
run it:
	./bin/Blink/Blink -h


Optional 'V=1' enables makefile verbosity
Optional 'D=1' enables core debug messages (same as Arduino IDE's tools/debug menu)
Optional 'OPTZ=-O2' will update gcc -O option (default is -Os, -D=1 implies -O0)
Optional 'FORCE32=0' will use native/default gcc (default is FORCE32=1 unless gcc-multilib is not detected)
Optional 'R="<options>"' (ex: R="-b -v") runs the executable with given options after build

Non exhaustive list of working examples:
	make D=1 ../../libraries/ESP8266WiFi/examples/udp/udp
	make D=1 ../../libraries/ESP8266WiFi/examples/WiFiClient/WiFiClient
	make D=1 ../../libraries/ESP8266WebServer/examples/HelloServer/HelloServer
	make D=1 ../../libraries/ESP8266WebServer/examples/AdvancedWebServer/AdvancedWebServer
	make D=1 ../../libraries/ESP8266mDNS/examples/mDNS_Web_Server/mDNS_Web_Server
	make D=1 ../../libraries/ESP8266WiFi/examples/BearSSL_Validation/BearSSL_Validation

Compile other sketches:
- library paths are specified using ULIBDIRS variable, separated by ':'
- call 'make path-to-the-sketch-file' to build (without its '.ino' extension):
- CAVEAT: functions must be declared *before* being called (arduino builder is not around)

	make D=1  ULIBDIRS=/path/to/your/arduino/libraries/lib1:/path/to/another/place/lib2  /path/to/your/sketchdir/sketch/sketch
  or:
	ULIBDIRS=/path/to/your/arduino/libraries/lib1:/path/to/another/place/lib2  make  D=1  /path/to/your/sketchdir/sketch/sketch

  or:
	export ULIBDIRS=/path/to/your/arduino/libraries/lib1:/path/to/another/place/lib2
	export D=1
	export OPTZ=-O2
	make clean
	make /path/to/your/sketchdir/sketch/sketch
	./bin/sketch/sketch

Additional flags:
    make USERCFLAGS="-I some/where -I some/where/else" \
         USERCSOURCES="some/where/file1.c some/where/file2.c ..." \
         USERCXXSOURCES="some/where/file3.cpp some/where/file4.cpp ..." \
         USERLDFLAGS="-L some/where/around" \
         ...

Executable location is always in bin/. Once a sketch is compiled, just run it:
	bin/sketch/sketch

Options are available:
	-h
	-i eth0		bind servers to this interface (WIP)
	-l		bind Multicast to the above interface (WIP)
	-c		ignore CTRL-C (send it over serial device)
	-f		no throttle (possibly 100%CPU)
	-S		spiffs size in KBytes (default: 1024)
			(negative value will force mismatched size)

TODO
----
A lot.
Make fun, propose PRs.

- replace some "fprintf(stderr" with redirectable log functions
- spiffs in a file (done, need to initialize and check)
- EEPROM in a file (partly done)
- SDCARD on Host filesystem ? or in an image ?
- nice curses interface to display/change gpios ?
- display device emulation (like ssd1306)
- optionally use arduino-builder ?
- store sketch objects and binaries outside from the source directories (done for sketches)
- compile and use lwIP on host
- easily debug HTTP classes
- https://github.com/esp8266/Arduino/issues/1715
- gpio, currently:
  read as 0(digital) or 512(analog).
  output is printed on console.

Make rules:

CI - run CI
test - run host test for CI
gcov - run coverage for CI
build-info - show toolchain version
ssl - download source and build BearSSL
list - show core example list