14 add a class for udp client #20

eigen-value · 2025-10-07T15:07:53Z

UDP class
This PR is also an API proposal of the following CPU-side methods:

udp/connect
udp/connectMulticast
udp/close
udp/write
udp/awaitRead
udp/read

mod: beginPacket sets remotes' IP/port

feat: implemented remaining methods impr: threading

mod: read stops if no remaining bytes mod: peek works only per-udp-packet impr: stop calls only if connected

…p-client # Conflicts: # src/Arduino_RouterBridge.h # src/tcp_client.h

CLAassistant · 2025-11-12T16:13:03Z

All committers have signed the CLA.

github-actions · 2025-11-12T16:45:02Z

Memory usage change @ 79f5565

Board	flash	%	RAM for global variables	%
`arduino:zephyr:unoq`	🔺 0 - +4	0.0 - 0.0	🔺 0 - +8	0.0 - 0.0

Click for full report table

Board	`examples/client` flash	%	`examples/client` RAM for global variables	%	`examples/clientSSL` flash	%	`examples/clientSSL` RAM for global variables	%	`examples/hci` flash	%	`examples/hci` RAM for global variables	%	`examples/monitor` flash	%	`examples/monitor` RAM for global variables	%	`examples/server` flash	%	`examples/server` RAM for global variables	%	`examples/simple_bridge` flash	%	`examples/simple_bridge` RAM for global variables	%	`examples/test` flash	%	`examples/test` RAM for global variables	%	`examples/udp_ntp_client` flash	%	`examples/udp_ntp_client` RAM for global variables	%
`arduino:zephyr:unoq`	4	0.0	8	0.0	4	0.0	8	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	N/A	N/A	N/A	N/A

Click for full report CSV

Board,examples/client<br>flash,%,examples/client<br>RAM for global variables,%,examples/clientSSL<br>flash,%,examples/clientSSL<br>RAM for global variables,%,examples/hci<br>flash,%,examples/hci<br>RAM for global variables,%,examples/monitor<br>flash,%,examples/monitor<br>RAM for global variables,%,examples/server<br>flash,%,examples/server<br>RAM for global variables,%,examples/simple_bridge<br>flash,%,examples/simple_bridge<br>RAM for global variables,%,examples/test<br>flash,%,examples/test<br>RAM for global variables,%,examples/udp_ntp_client<br>flash,%,examples/udp_ntp_client<br>RAM for global variables,%
arduino:zephyr:unoq,4,0.0,8,0.0,4,0.0,8,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,N/A,N/A,N/A,N/A

cmaglie · 2025-11-13T13:56:41Z

src/udp_bridge.h

+    }
+
+    uint8_t beginMulticast(IPAddress ip, uint16_t port) override {
+


Suggested change

Why do some methods have this extra blank line at the beginning? Personally, I'd like to remove it because it's really odd to have this double standard; the blanks in the middle of a method may make sense, but at least we could spare the blank at the beginning of the function.

done in:
1037bd9

cmaglie · 2025-11-13T13:57:40Z

src/udp_bridge.h

+        k_mutex_lock(&udp_mutex, K_FOREVER);
+
+        String hostname = ip.toString();
+        const bool ok = _connected || bridge->call(UDP_CONNECT_MULTI_METHOD, hostname, port).result(connection_id);


Same concerns as for the begin(port)

see
1037bd9

cmaglie · 2025-11-13T14:03:59Z

src/udp_bridge.h

+
+        if (_connected) {
+            String msg;
+            _connected = !bridge->call(UDP_CLOSE_METHOD, connection_id).result(msg);


The udp/close will always close the connection and drop the connection_id on the Linux side.

Suggested change

_connected = !bridge->call(UDP_CLOSE_METHOD, connection_id).result(msg);

bridge->call(UDP_CLOSE_METHOD, connection_id).result(msg);

_connected = false;

This is just to make sure the bridge->call went through without errors on the other side

cmaglie · 2025-11-13T14:09:37Z

src/udp_bridge.h

+
+        if (!connected()) return 0;
+
+        MsgPack::arr_t<uint8_t> payload;
+
+        for (size_t i = 0; i < size; ++i) {
+            payload.push_back(buffer[i]);
+        }
+
+        size_t written;
+        const bool ok = bridge->call(UDP_WRITE_METHOD, connection_id, _targetHost, _targetPort, payload).result(written);
+        return ok? written : 0;


I believe this isn't the intended use of this API. Once you use beginPacket, all subsequent write calls will add data to that packet, and it will be sent in one go as a single UDP packet when endPacket is called.
The call to udp/write must be done in the endPacket method.

In other words, the following:

udp.beginPacket("1.2.3.4", 1234); udp.write("hello", 5); udp.endPacket();

must be equivalent to:

udp.beginPacket("1.2.3.4", 1234); udp.write("hel", 3); udp.write("l", 1); udp.write("o", 1); udp.endPacket();

This depends on how the other side handles the udp/write method (ie always requiring IP and port).
Besides if the udpBridge library is meant to hold the UDP packet in a buffer up until the user is ready to send, then such buffer should be the max size of a UDP packet (64k)

Should we extend the UDP API on the router to handle multiple writes? (as we did for the reading side)

cmaglie · 2025-11-13T14:13:08Z

src/udp_bridge.h

+
+        // if (async_res.error.code > NO_ERR) {
+        //     _connected = false;
+        // }


Suggested change

// if (async_res.error.code > NO_ERR) {

// _connected = false;

// }

cmaglie · 2025-11-13T14:18:52Z

src/udp_bridge.h

+        k_mutex_lock(&udp_mutex, K_FOREVER);
+
+        String hostname = "0.0.0.0";
+        const bool ok = _connected || bridge->call(UDP_CONNECT_METHOD, hostname, port).result(connection_id);
+        _connected = ok;
+        if (_connected) _port = port;
+
+        k_mutex_unlock(&udp_mutex);


If I read this correctly, a double call to begin(port) will return 1 (aka success) even if the second operation would be a no-op:

udp.begin(3000); // returns 1 udp.begin(4444); // returns 1 as well, but 0 is expected

I would expect a return value of 0 in the second call. Additionally, the internal field _port is updated to the value 4444, while the UDP listener on the Linux side remains unchanged.

Suggested change

k_mutex_lock(&udp_mutex, K_FOREVER);

String hostname = "0.0.0.0";

const bool ok = _connected || bridge->call(UDP_CONNECT_METHOD, hostname, port).result(connection_id);

_connected = ok;

if (_connected) _port = port;

k_mutex_unlock(&udp_mutex);

k_mutex_lock(&udp_mutex, K_FOREVER);

bool ok = false;

if (!_connected) {

String hostname = "0.0.0.0";

ok = bridge->call(UDP_CONNECT_METHOD, hostname, port).result(connection_id);

if (ok) {

_port = port;

_connected = true;

}

}

k_mutex_unlock(&udp_mutex);

you are right. It should be fixed here:
1037bd9

cmaglie · 2025-11-13T14:25:23Z

src/udp_bridge.h

+    int parsePacket() override {
+        k_mutex_lock(&udp_mutex, K_FOREVER);
+
+        while (_remaining) read();  // ensure previous packet is read


This isn't necessary; the RPC API can skip the current UDP packet being read, even if it is not fully consumed.
You can simply set _remaining to 0, with some buffer cleanup if necessary, which should be much quicker than processing the entire packet.

The call to read() is meant just for flushing in this context.
Again this is a problem of sync between the two sides.
If MCU is not interested in a packet anymore and such packet was not entirely received via RPCs then the MCU should have a method to signal this to the other side.

Calling udp/awaitRead on the router will automatically drop the unread packet on the Linux side.
You can partially read a packet and await the next one; the piece that you didn't read is lost, but this is allowed on the router API.

cmaglie · 2025-11-13T14:27:06Z

src/udp_bridge.h

+        RpcResult async_res = bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout);
+        const bool ret = _connected && async_res.result(packet_meta);


Suggested change

RpcResult async_res = bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout);

const bool ret = _connected && async_res.result(packet_meta);

const bool ret = _connected && bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout).result(packet_meta);

This makes no difference.
async_res could be used later for error handling

It seems a bit weird to create an async_res object that may not be consumed later, if _connected is false the && operation is short-circuited and the result method is not called.

…he other side

github-actions · 2025-11-13T15:39:48Z

Memory usage change @ 1037bd9

Board	flash	%	RAM for global variables	%
`arduino:zephyr:unoq`	🔺 0 - +4	0.0 - 0.0	🔺 0 - +8	0.0 - 0.0

Click for full report table

Board	`examples/client` flash	%	`examples/client` RAM for global variables	%	`examples/clientSSL` flash	%	`examples/clientSSL` RAM for global variables	%	`examples/hci` flash	%	`examples/hci` RAM for global variables	%	`examples/monitor` flash	%	`examples/monitor` RAM for global variables	%	`examples/server` flash	%	`examples/server` RAM for global variables	%	`examples/simple_bridge` flash	%	`examples/simple_bridge` RAM for global variables	%	`examples/test` flash	%	`examples/test` RAM for global variables	%	`examples/udp_ntp_client` flash	%	`examples/udp_ntp_client` RAM for global variables	%
`arduino:zephyr:unoq`	4	0.0	8	0.0	4	0.0	8	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	N/A	N/A	N/A	N/A

Click for full report CSV

Board,examples/client<br>flash,%,examples/client<br>RAM for global variables,%,examples/clientSSL<br>flash,%,examples/clientSSL<br>RAM for global variables,%,examples/hci<br>flash,%,examples/hci<br>RAM for global variables,%,examples/monitor<br>flash,%,examples/monitor<br>RAM for global variables,%,examples/server<br>flash,%,examples/server<br>RAM for global variables,%,examples/simple_bridge<br>flash,%,examples/simple_bridge<br>RAM for global variables,%,examples/test<br>flash,%,examples/test<br>RAM for global variables,%,examples/udp_ntp_client<br>flash,%,examples/udp_ntp_client<br>RAM for global variables,%
arduino:zephyr:unoq,4,0.0,8,0.0,4,0.0,8,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,N/A,N/A,N/A,N/A

eigen-value added 5 commits September 22, 2025 20:24

feat: basic udp_bridge class implementing Udp

1759edb

mod: begin methods establish connection

354e503

mod: beginPacket sets remotes' IP/port

Merge branch 'main' into 14-add-a-class-for-udp-client

9fde055

mod: rem atomic flags, increased udp buffer size

e3efe47

feat: implemented remaining methods impr: threading

mod: default buffer size

5d692ce

mod: read stops if no remaining bytes mod: peek works only per-udp-packet impr: stop calls only if connected

eigen-value requested a review from cmaglie October 7, 2025 15:07

eigen-value linked an issue Oct 7, 2025 that may be closed by this pull request

Add a class for UDP client #14

Open

eigen-value added the enhancement New feature or request label Oct 7, 2025

eigen-value added 10 commits October 20, 2025 15:25

impr: udp testing

cd023d5

fix: udp bridge using tcp method

0d87a0c

examples: udp echo test

5fc1ec1

examples: fix udp_echo .py server. redundant socket

a4c8b5c

examples: independent python udp server

43bf054

feat: udp and tcp read_timeout

e191122

fix: echo example using undefined method

138de80

Merge remote-tracking branch 'origin/main' into 14-add-a-class-for-ud…

1825fee

…p-client # Conflicts: # src/Arduino_RouterBridge.h # src/tcp_client.h

mod: parsing packet header according to arduino/arduino-router#3

cc24225

impr: rem repeated reads when temp_buffer has bytes

d74e7ea

eigen-value marked this pull request as ready for review November 10, 2025 15:07

eigen-value and others added 2 commits November 12, 2025 16:49

mod: UDP read_timeout default to 1 ms

a19ccc8

Added NTP Client example

275d355

eigen-value added 3 commits November 12, 2025 17:15

mod: moving udp examples to tests

20f7bea

Merge branch 'main' into 14-add-a-class-for-udp-client

d204ab6

fix: restore hci.h

79f5565

cmaglie requested changes Nov 13, 2025

View reviewed changes

fix: repeated calls to begin will change the port without signaling t…

1037bd9

…he other side

		}

		uint8_t beginMulticast(IPAddress ip, uint16_t port) override {

	_connected = !bridge->call(UDP_CLOSE_METHOD, connection_id).result(msg);
	bridge->call(UDP_CLOSE_METHOD, connection_id).result(msg);
	_connected = false;

		RpcResult async_res = bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout);
		const bool ret = _connected && async_res.result(packet_meta);

	RpcResult async_res = bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout);
	const bool ret = _connected && async_res.result(packet_meta);
	const bool ret = _connected && bridge->call(UDP_AWAIT_READ_METHOD, connection_id, read_timeout).result(packet_meta);

14 add a class for udp client #20

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