wasm-micro-runtime/samples/socket-api
Marcin Kolny f96773410a
Fix bind() calls to receive the correct size of sockaddr structure (#1490)
For some implementations (e.g. Mac OS) `bind()` requires the length to be exactly
equal to either `sockaddr_in` or `sockaddr_in6` structure. Because we always used
 `sizeof(struct sockaddr_storage)`, `bind()` was returning errors. In this change we
 fix the behavior. See StackOverflow [1] for details.

[1] https://stackoverflow.com/questions/73707162/socket-bind-failed-with-invalid-argument-error-for-program-running-on-macos
2022-09-16 11:09:03 +08:00
..
wasm-src Fix bind() calls to receive the correct size of sockaddr structure (#1490) 2022-09-16 11:09:03 +08:00
CMakeLists.txt Implement sock_send_to and sock_recv_from system calls (#1457) 2022-09-13 09:00:05 +08:00
README.md Added http downloader and multicast socket options (#1467) 2022-09-15 17:09:39 +08:00

"socket-api" sample introduction

This sample demonstrates how to use WAMR socket-api to develop wasm network applications. Two wasm applications are provided: tcp-server and tcp-client, and this sample demonstrates how they communicate with each other.

Preparation

Please install WASI SDK, download the wasi-sdk release and extract the archive to default path /opt/wasi-sdk. And install wabt, download the wabt release and extract the archive to default path /opt/wabt

Build the sample

mkdir build
cd build
cmake ..
make

iwasm and three Wasm modules, tcp_server.wasm, tcp_client.wasm, send_recv.wasm will be generated. And their corresponding native version, tcp_server, tcp_client, send_recv are generated too.

Note that iwasm is built with libc-wasi and lib-pthread enabled.

Run workload

Start the tcp server, which opens port 1234 and waits for clients to connect.

cd build
./iwasm --addr-pool=0.0.0.0/15 tcp_server.wasm

Start the tcp client, which connects the server and receives message.

cd build
./iwasm --addr-pool=127.0.0.1/15 tcp_client.wasm

The output of client is like:

[Client] Create socket
[Client] Connect socket
[Client] Client receive
[Client] 115 bytes received:
Buffer recieved:
Say Hi from the Server
Say Hi from the Server
Say Hi from the Server
Say Hi from the Server
Say Hi from the Server

[Client] BYE

send_recv.wasm contains a thread as a server and a thread as a client. They send and receive data via 127.0.0.1:1234.

$ ./iwasm --addr-pool=127.0.0.1/0  ./send_recv.wasm

The output is:

Server is online ...
Client is running...
Start receiving.
Start sending.
Send 106 bytes successfully!
Receive 106 bytes successlly!
Data:
  The stars shine down
  It brings us light
  Light comes down
  To make us paths
  It watches us
  And mourns for us

socket_opts.wasm shows an example of getting and setting various supported socket options

$ ./iwasm ./socket_opts.wasm

The output describes the different socket options that are set & retrieved, like so:

[Client] Create TCP socket
[Client] Create UDP socket
[Client] Create UDP IPv6 socket
SO_RCVTIMEO tv_sec is expected
SO_RCVTIMEO tv_usec is expected
...
[Client] Close sockets

Refer to socket api document for more details.