Example app add_two_ints_service does not work on STM32: 1) Incorrect data received and 2) No server response

Issue template

• Hardware description: Olimex STM32-E407
• RTOS: freeRTOS
• Installation type: micro_ros_setup
• Version or commit hash: galactic

Steps to reproduce the issue

• Follow steps mentioned in micro.ros.org using docker (ros:galactic)
• Configure firmware with udp transport ros2 run micro_ros_setup configure_firmware.sh add_two_ints_service --transport udp --ip <our agent ip> --port 8888
• Build firmware and flash through JTAG, just as in the tutorial.
• Create and run the agent.
• Service call on a new terminal: ros2 service call /addtwoints example_interfaces/srv/AddTwoInts "{a: 5, b: 10}"

Expected behavior

Should get a response (sum=15)

Actual behavior

1. Server receives request but there is no response.
   waiting for service to become available... requester: making request: example_interfaces.srv.AddTwoInts_Request(a=5, b=10)
2. Received request has garbage values for a, and b is always 1.

Additional information

We basically have the same issue as this but with FreeRTOS on our STM32 board.
We using a router from Teltonika- RUT240 (which a decent router), and the computer running the agent and making service calls is connected though Ethernet.

Quick note: I had to include #include <rclc/executor.h> in the example code, and change "printk"s to printf to get it to compile.

Not very well-versed with uROS or DDS stuff, but we tried the following:

1. export RMW_IMPLEMENTATION=rmw_fastrtps_cpp before starting the agent, as suggested in this thread.
2. Making the response and request variables global suggested in this thread.

Logs from the agent:

$ ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888 -v6
[1646402745.031716] info     | UDPv4AgentLinux.cpp | init                     | running...             | port: 8888
[1646402745.032007] info     | Root.cpp           | set_verbose_level        | logger setup           | verbose_level: 6
[1646402745.756195] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x00000000, len: 24, data: 
0000: 80 00 00 00 00 01 10 00 58 52 43 45 01 00 01 0F 09 6C 59 A4 81 00 FC 03
[1646402745.756401] info     | Root.cpp           | create_client            | create                 | client_key: 0x096C59A4, session_id: 0x81
[1646402745.756505] info     | SessionManager.hpp | establish_session        | session established    | client_key: 0x096C59A4, address: 192.168.10.18:12020
[1646402745.756658] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 19, data: 
0000: 81 00 00 00 04 01 0B 00 00 00 58 52 43 45 01 00 01 0F 00
[1646402745.757560] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 56, data: 
0000: 81 80 00 00 01 07 2E 00 00 0A 00 01 01 03 00 00 20 00 00 00 00 01 00 20 18 00 00 00 61 64 64 5F
0020: 74 77 6F 69 6E 74 73 5F 73 65 72 76 65 72 5F 72 63 6C 63 00 00 00 00 00
[1646402745.771891] info     | ProxyClient.cpp    | create_participant       | participant created    | client_key: 0x096C59A4, participant_id: 0x000(1)
[1646402745.771982] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 14, data: 
0000: 81 80 00 00 05 01 06 00 00 0A 00 01 00 00
[1646402745.771996] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 01 00 00 00 80
[1646402745.772787] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 01 00 00 00 80
[1646402745.773173] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 208, data: 
0000: 81 80 01 00 01 07 C5 00 00 0B 00 08 08 03 00 00 B7 00 00 00 0C 00 00 00 2F 61 64 64 74 77 6F 69
0020: 6E 74 73 00 33 00 00 00 65 78 61 6D 70 6C 65 5F 69 6E 74 65 72 66 61 63 65 73 3A 3A 73 72 76 3A
0040: 3A 64 64 73 5F 3A 3A 41 64 64 54 77 6F 49 6E 74 73 5F 52 65 71 75 65 73 74 5F 00 08 34 00 00 00
0060: 65 78 61 6D 70 6C 65 5F 69 6E 74 65 72 66 61 63 65 73 3A 3A 73 72 76 3A 3A 64 64 73 5F 3A 3A 41
0080: 64 64 54 77 6F 49 6E 74 73 5F 52 65 73 70 6F 6E 73 65 5F 00 01 23 03 08 15 00 00 00 72 71 2F 61
00A0: 64 64 74 77 6F 69 6E 74 73 52 65 71 75 65 73 74 00 01 00 00 13 00 00 00 72 72 2F 61 64 64 74 77
00C0: 6F 69 6E 74 73 52 65 70 6C 79 00 00 01 00 00 00
[1646402745.773799] info     | ProxyClient.cpp    | create_replier           | replier created        | client_key: 0x096C59A4, requester_id: 0x000(7), participant_id: 0x000(1)
[1646402745.773880] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 14, data: 
0000: 81 80 01 00 05 01 06 00 00 0B 00 08 00 00
[1646402745.773894] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 02 00 00 00 80
[1646402745.774660] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 02 00 00 00 80
[1646402745.774678] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 24, data: 
0000: 81 80 02 00 08 01 10 00 00 0C 00 08 80 00 00 01 FF FF 00 00 00 00 00 00
[1646402745.774818] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 03 00 00 00 80
[1646402768.908714] debug    | Replier.cpp        | read_fn                  | [==>> DDS <<==]        | client_key: 0x00000000, len: 56, data: 
0000: 69 F5 10 01 90 E8 E4 52 F3 48 EC 0C 00 00 14 03 00 00 00 00 01 00 00 00 AB CE 57 FA 4A 37 B3 F7
0020: 01 00 00 00 00 00 00 00 05 00 00 00 00 00 00 00 0A 00 00 00 00 00 00 00
[1646402768.908912] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 68, data: 
0000: 81 80 02 00 09 01 3C 00 00 0C 00 08 69 F5 10 01 90 E8 E4 52 F3 48 EC 0C 00 00 14 03 00 00 00 00
0020: 01 00 00 00 AB CE 57 FA 4A 37 B3 F7 01 00 00 00 00 00 00 00 05 00 00 00 00 00 00 00 0A 00 00 00
0040: 00 00 00 00
[1646402768.973465] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 03 00 00 00 80
[1646402768.977226] debug    | UDPv4AgentLinux.cpp | recv_message             | [==>> UDP <<==]        | client_key: 0x096C59A4, len: 44, data: 
0000: 81 80 03 00 07 01 24 00 00 0D 00 08 69 F5 10 01 90 E8 E4 52 F3 48 EC 0C 00 00 14 03 00 00 00 00
0020: 01 00 00 00 AC CE 57 FA 4A 37 B3 F7
[1646402768.977451] debug    | Replier.cpp        | write                    | [** <<DDS>> **]        | client_key: 0x00000000, len: 32, data: 
0000: 69 F5 10 01 90 E8 E4 52 F3 48 EC 0C 00 00 14 03 00 00 00 00 01 00 00 00 AC CE 57 FA 4A 37 B3 F7
[1646402768.977570] debug    | UDPv4AgentLinux.cpp | send_message             | [** <<UDP>> **]        | client_key: 0x096C59A4, len: 13, data: 
0000: 81 00 00 00 0A 01 05 00 04 00 00 00 80

从 apps/add_two_ints_service/app.c 开始，重点查看第 47 行引用的 request 和 response 变量，并使用 FreeRTOS 教程、UDP 配置以及所示的 service call 重现该问题。将接收到的值与预期的 request 进行比较，并确认 service 返回 sum=15；issue 中未提及测试文件。