[TW#25858] esp-now support broadcast?

[limin-liu]

In your decribetion of code :
WIFI
3. Allow sending a broadcast ESP-NOW packet, but make sure that the packet is unencrypted;

But in your reference V2.1.0 :
3.8 part for ESPNOW still "ESP-NOW do not support broadcast and multicast.“

So ESPNOW actually support broadcast or not？

[FayeY]

Hi, ESP-NOW does support broadcast in ESP8266 non OS SDK V2.1, we will revise the documentation.
Thanks for reporting!

[limin-liu]

in the description for this repository's new update code . link here --->90c641e

Version 2.1.0(116b762)

System

1. Fix and update the license;
2. Add definitions of ROM functions;
3. Add efuse mac crc, save efuse mac into the system parameter area of flash, as a backup mac;
4. Implement uart_div_modify, which can support a 32-bit DivLatchValue in the SDK instead of the ROM one, and also remove uart_div_modify from the ld file;
5. Reduce iRAM usage by transferring some functions to flash；
   • add weak function void user_spi_flash_dio_to_qio_pre_init(void). If the dio to qio flash mode is not used, users can add an empty user_spi_flash_dio_to_qio_pre_init on the application side to reduce iRAM usage;
6. Fix WDT in system_restart;
7. Fix Write & Read issue in SPI overlap mode;
8. Support 8MB & 16MB spi flash;
9. Update boot v1.7;
   • Support 8MB & 16MB spi flash;
   • Try boot the first bin for 3 times. If it fails, then boot the backup bin;
10. Fix http packet error, BBP301;
11. Support long periods of deep sleep;
12. Fix NMI handle crash on unaligned memory access, BBP309;

Lwip

1. Add set and get dns server APIs:
   • espconn_dns_setserver
   • espconn_dns_getserver
2. Fix 2038 overflow bug in sntp_get_current_timestamp;
3. Fix MTU negotiate bug;

AT

1. Add new commands, AT+UART? and AT+UART_DEF?;
2. Add new command, AT+SYSRAM?;
3. Add new commands, AT+SYSIO series;
4. Add new command, AT+CWHOSTNAME;
5. Add new command, AT+SYSADC?;
6. Add new commands, AT+CIPSNTPCFG and AT+CIPSNTPTIME;
7. Add new commands, AT+CIPDNS_CUR and AT+CIPDNS_DEF;
8. Support a maximum of 8 stations;
9. Modify keepalive count to 3 times;
10. Fix scan hidden ssid issue in AT+CWLAP;
11. Fix the issue of the UART stop bit being 0 when queried for the first time;
12. Fix MAC addr conflict in AP+STA mode;
13. Add new commands, AT+RFAUTOTRACE;

WiFi

1. Optimize the RF frequency calibration workflow, having the frequency trace disabled by default;
   • users can call system_phy_freq_trace_enable in user_rf_pre_init to enable it;
2. Update libphy.a to version 1134_0;
3. Allow sending a broadcast ESP-NOW packet, but make sure that the packet is unencrypted;
4. Fix soft queue error;
5. Fix EVENT_STAMODE_AUTHMODE_CHANGE event mode info;
6. Fix lmac assert;
7. Fix bug in sniffer mode;
8. Fix arp loss continously issue;
9. Fix bug in WiFi event;
   • auth mode changed event cannot be throw when station is in the process of scanning;
   • error old auth mode and new auth mode;
   • op mode change process cannot be blocked, so add an event to notify the caller that op mode is changed;
10. Fix the bug in mic failure handler;
11. Fix the bug which causes failure of connection to an AP with shared WEP;
12. Fix the bug which causes failure of connection to an AP with hidden ssid;
13. Fix softAP deauth;
14. Fix reconnect policy when trying to connect to an AP that does not exist;
15. Fix scan issue;
16. Fix extra bytes in UDP broadcast packet, BBP310;

[FayeY]

Hi, thanks for your reporting. The documentation has been updated, see Chapter 3.8 in API Guide.
ESP-NOW supports broadcast in V2.1.

[franklinvv]

How can we perform a broadcast with ESP-NOW? Do we transmit to mac address {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}? Because I tried that and it didn't seem to work ...

I would like to use broadcasts to let ESP-NOW devices discover other devices, with which they haven't paired yet. Is that possible?

Could you enlighten me, @FayeY ?

[Daniel-dk]

from the header file it seems we have to set it to "null"
"

/**
  * @brief     Send ESPNOW data
  *
  * @attention 1. If peer_addr is not NULL, send data to the peer whose MAC address matches peer_addr
  * @attention 2. If peer_addr is NULL, send data to all of the peers that are added to the peer list
  * @attention 3. The maximum length of data must be less than ESP_NOW_MAX_DATA_LEN
  * @attention 4. The buffer pointed to by data argument does not need to be valid after esp_now_send returns
  *
  * @param     peer_addr  peer MAC address
  * @param     data  data to send
  * @param     len  length of data
  *
  * @return
  *          - ESP_OK : succeed
  *          - ESP_ERR_ESPNOW_NOT_INIT : ESPNOW is not initialized
  *          - ESP_ERR_ESPNOW_ARG : invalid argument
  *          - ESP_ERR_ESPNOW_INTERNAL : internal error
  *          - ESP_ERR_ESPNOW_NO_MEM : out of memory
  *          - ESP_ERR_ESPNOW_NOT_FOUND : peer is not found
  *          - ESP_ERR_ESPNOW_IF : current WiFi interface doesn't match that of peer
  */
esp_err_t esp_now_send(const uint8_t *peer_addr, const uint8_t *data, size_t len);

I don't have multiple ESP32's to test with yet, will report once I do,
It seems that all peers still need to be in the peer list , but it seems that they will still recieve broadcast messages anyway ( from the API docs )

the MAC header is a little different from that of standard frames. The FromDS and ToDS bits of FrameControl field are both 0. The first address field is set to the destination address. The second address field is set to the source address. The third address field is set to broadcast address(0xff:0xff:0xff:0xff:0xff:0xff).

We also need to add a Peer to the peer list with MAC addr FF:FF:FF:FF:FF:FF

From this example it seems that un-peered devices will still recieve Broadcasts ( as expected )

[franklinvv]

That’s not a real broadcast if you ask me. I haven’t looked at the source code, but I presume that it just loops through the peers one by one, doesn’t it? It would be cool to allow ESPs to discover each other by broadcasting, and then adding each other as peers.

…

Op 27 nov. 2017 om 19:34 heeft Daniel ***@***.***> het volgende geschreven: from the header file it seems we have to set it to "null" " /** * @brief Send ESPNOW data * * @attention 1. If peer_addr is not NULL, send data to the peer whose MAC address matches peer_addr * @attention 2. If peer_addr is NULL, send data to all of the peers that are added to the peer list * @attention 3. The maximum length of data must be less than ESP_NOW_MAX_DATA_LEN * @attention 4. The buffer pointed to by data argument does not need to be valid after esp_now_send returns * * @param peer_addr peer MAC address * @param data data to send * @param len length of data * * @return * - ESP_OK : succeed * - ESP_ERR_ESPNOW_NOT_INIT : ESPNOW is not initialized * - ESP_ERR_ESPNOW_ARG : invalid argument * - ESP_ERR_ESPNOW_INTERNAL : internal error * - ESP_ERR_ESPNOW_NO_MEM : out of memory * - ESP_ERR_ESPNOW_NOT_FOUND : peer is not found * - ESP_ERR_ESPNOW_IF : current WiFi interface doesn't match that of peer */ esp_err_t esp_now_send(const uint8_t *peer_addr, const uint8_t *data, size_t len); I don't have multiple ESP32's to test with yet, will report once I do — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[Daniel-dk]

It seems its a real broadcast ..
if you send unencrypted data to peer addr ff:ff:ff:ff:ff:ff then any device on the same channel will receive it
You need to add a peer with Addr ff:ff:ff:ff:ff:ff to the peer list otherwise it doesnt send the packet..

Device A :

Sending: 29
Send Status: Success
Last Packet Sent to: ff:ff:ff:ff:ff:ff
Last Packet Send Status: Delivery Success

Device B  : 
Last Packet Recv from: 24:0a:c4:yy:yy:yy
Last Packet Recv Data: 29

test .ino here ( quick modified version of the esp-Now example, flashed to 2 ESP32 dev boards )
Gist link

[franklinvv]

Oh, then I stand corrected!

However, I only have one ESP32 so I can't test it on the ESP32. I have multiple ESP8266s so I will have a try asap. 🙂 Or did you already try it with multiple ESP8266s?

[cnlohr]

This doesn't seem to be working for me. I am able to send things freely when I call

	esp_now_send(da, "ESP8266", 8 ); /*Also tried sending to null */

However, I never seem to be able to receive anything. I've tried adding many different combinations but even this...

	esp_now_register_recv_cb(espnowcb);
	esp_now_register_send_cb(espnowcbtx);
	uint8_t routermac[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff,}; //Src Address of my router.
	printf( "PEERINFO: %d\n", esp_now_add_peer(routermac, ESP_NOW_ROLE_COMBO, 0, 0, 0) );
	esp_now_set_self_role(ESP_NOW_ROLE_COMBO);

Nothing gets received.

I am able to look at Wireshark and see appropriate messages going back and forth.

One note: Your protocol described here: http://esp-idf.readthedocs.io/en/latest/api-reference/wifi/esp_now.html is incomplete. There are 4 undocumented bytes between the vendor-specific action frame and vendor-specific action content. I still do not understand what they do.

[Crazor]

I encountered the same issue as @cnlohr where I can successfully send to FF:FF:FF:FF:FF:FF, but those broadcast packets are never received.
@Daniel-dk said it is needed to add the broadcast address as a peer, however that fails with a return code of -3 (I haven't found any explanation of this function's return codes).
I'm on SDK 2.2.1 (via the Arduino core 2.4.1)

[cnlohr]

@FayeY Can we please re-open this issue as it is definitely present in the current nonos sdk. I am stuck back at 1.5.2 for projects where this is needed.

[littleyoda]

I have the same Problem with esp8266. I can send boardcasts, but no esp8266 receive them.

[cnlohr]

Indeed. the issue is still very much open and very much a problem with the official NONOS sdk. I am not sure why espressif is leaving this issue closed.