wasm-micro-runtime/product-mini/platforms/zephyr/simple-http

Socket sample

this sample demonstrates the use of WASI API to interact with sockets.

❗ Important: This sample was ported/adapted from the http_get zephyr sample. The original sample can be found here.

🛠️ Work in progress: The sample is functional but be aware that just a small part of WASI socket API was tested. Actual Zephyr APIs:

• socket creation = zsock_socket
• socket connection = zsock_connect
• socket emission = zsock_sendto
• socket reception = zsock_recvfrom
• socket destruction = zsock_close

With the sockets most API are in fact provided by the runtime instead of WASI because of the lack of socket support in WASI preview1.

Setup

1. Connect a network cable to the board ethernet port.

2. Configure the network interface on the host machine

   Internet Protocol Version 4 (TCP/IPv4) Properties:
       IP Address:         192.0.2.10
       Subnet Mask:        255.255.255.0
       Default Gateway:    192.0.2.2
   

3. Start a simple HTTP server on the host machine.

   python3 -m http.server --bind 0.0.0.0
   

4. Disable any firewall that may block the connection.

Configuration

To configure the server side IP address and port modify the following lines in the http_get.c file.

1. The HTTP_HOST and HTTP_PORT macros define the server IP address and port.

   /* HTTP server to connect to */
   #define HTTP_HOST "192.0.2.10"
   /* Port to connect to, as string */
   #define HTTP_PORT "8000"
   /* HTTP path to request */
   #define HTTP_PATH "/"
   
   // ...
   
   #define REQUEST "GET " HTTP_PATH " HTTP/1.0\r\nHost: " HTTP_HOST "\r\n\r\n"
   

   📄 Notes: These macros are used to build the request string, but they are not used to instantiate the address structure. Because at one point we didn't want to use inet_pton to convert the string to an address and it remained like this.

2. The addr structure is used to store the server address.

   addr.sin_port = htons(8000);
       addr.sin_addr.s_addr =
           htonl(0xC000020A); // hard coded IP address for 192.0.2.10
   

To configure the authorized IP address(es) modify the following lines in the main.c file. WAMR will only allow the IP addresses in the pool to connect to the server.

#define ADDRESS_POOL_SIZE 1
    const char *addr_pool[ADDRESS_POOL_SIZE] = {
        "192.0.2.10/24",
    };

Run Command

• Zephyr Build

  1. Build: Replace nucleo_h743zi with your board name and the WAMR_BUILD_TARGET in CMakeList.txt with your target architecture.

     ZEPHYR_BASE=~/zephyrproject/zephyr \
     WAMR_ROOT_DIR=~/wasm-micro-runtime \
     WASI_SDK_PATH=~/wasi-sdk-21.0 \
     WAMR_APP_FRAMEWORK_DIR=~/wamr-app-framework \
     west build . -b nucleo_h563zi -p always 
     

     ⚠️ Warning: The flags ZEPHYR_BASE, WAMR_ROOT_DIR, WASI_SDK_PATH, and WAMR_APP_FRAMEWORK_DIR need to be set otherwise the build will fail.

  2. Flash:

     ZEPHYR_BASE=~/zephyrproject/zephyr west flash
     

  3. Monitor: Use a serial link to monitor the output. Personally, I use minicom.

     minicom -D /dev/ttyACM0
     

  4. Debug: Curently investigating.

• WebAssembly Module

  ❗ Important: I used wasi-sdk 21 to compile the module. I still haven't tried the module with the new wasi-sdk 22.

  1. Compile a static lib: in the wasm-apps folder.

     • Compile the an object:

       ~/wasi-sdk-21.0/bin/clang --sysroot=/home/user/wasi-sdk-21.0/share/wasi-sysroot -Iinc/ -c inc/wasi_socket_ext.c -o inc/wasi_socket_ext.o
       

     • Create a static lib:

       ~/wasi-sdk-21.0/bin/llvm-ar rcs inc/libwasi_socket_ext.a inc/wasi_socket_ext.o
       

  2. Compile: in the wasm-apps folder.

     ~/wasi-sdk-21.0/bin/clang --sysroot=/home/user/wasi-sdk-21.0/share/wasi-sysroot -Iinc/ -nodefaultlibs -o http_get.wasm http_get.c -lc -Linc/ -lwasi_socket_ext -z stack-size=8192 -Wl,--initial-memory=65536 -Wl,--export=__heap_base -Wl,--export=__data_end  -Wl,--allow-undefined
     

  3. generate a C header: Use xxd or other tool, I also put simple python script. At application root simple-http/.

     python3 to_c_header.py
     

     Be free to modify the script to fit your needs.

Output

The output should be similar to the following:

*** Booting Zephyr OS build v3.6.0-4305-g2ec8f442a505 ***
[00:00:00.061,000] <inf> net_config: Initializing network
[00:00:00.067,000] <inf> net_config: Waiting interface 1 (0x2000a910) to be up...
[00:00:03.158,000] <inf> phy_mii: PHY (0) Link speed 100 Mb, full duplex

[00:00:03.288,000] <inf> net_config: Interface 1 (0x2000a910) coming up
[00:00:03.295,000] <inf> net_config: IPv4 address: 192.0.2.1
global heap size: 131072
Wasm file size: 36351
main found
[wasm-mod] Preparing HTTP GET request for http://192.0.2.10:8000/
[wasm-mod] sock = 3
[wasm-mod] connect rc = 0
[wasm-mod] send rc = 36
[wasm-mod] Response:

HTTP/1.0 200 OK
Server: SimpleHTTP/0.6 Python/3.10.10
Date: Fri, 14 Jun 2024 07:26:56 GMT
Content-type: text/html; charset=utf-8
Content-Length: 2821

# Skip the HTML content

[wasm-mod] len = 0 break

[wasm-mod] Connection closed
main executed
wasi exit code: 0
elapsed: 405ms