Network support for WASI preview 2 #40
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dsseng
commented
Aug 2, 2025
dsseng
commented
- Add _AF_INET6 for WASI sockets
- HACK: explicitly default TCP listeners to 0.0.0.0
- Initial WASIp2 network driver
- fixup! Initial WASIp2 network driver
- net: wasip2: implement GetHostByName
- net: wasip2: refactor, support TCP connect
- net: wasip2: UDP client
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Very interesting work in progress here @dsseng 👀 |
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Okay, UDP server needs more work in common code, let's review this as is and keep UDP server for later |
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Paging Dr. @dgryski 😸 |
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@dsseng this is really interesting. Can you please point me to some example of this in use, so I can try it out! |
Not at my PC now. Please try http Server and Client samples from Go by example, should work for TCP. I probably also used the UDP client from there |
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@dsseng perhaps when you are back around, you can provide specific instructions on how you built and tested this? What code you built, what command you built it with, and how you executed it please. Thank you! |
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This includes PATH env for the needed components. These are the samples that should work: Full command: |
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Do you need the newer (v123) binaryen from with these versions: Any thoughts? |
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Weird. I did not see such an error. Is it HTTP client? Try http server, and try adding some logging. I will probably be able to try to reproduce in no shorter than a week, unfortunately too busy now |
| a := []udp.OutgoingDatagram{ | ||
| { | ||
| Data: cm.NewList(&buf[0], len(buf)), | ||
| // RemoteAddress: cm.Some(c.raddr), |
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Should this be commented out? If so, remove. Otherwise, probably worth fixing. Does the remote address get set somewhere else?
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This looked interesting for some work I am doing, so I tested it, but I am encountering an issue when sending data larger than 4096 bytes. What I tested: package main
import (
"fmt"
"net"
)
func main() {
conn, err := net.Dial("tcp", "localhost:8092")
if err != nil {
panic(err)
}
defer conn.Close()
buf := make([]byte, 4097)
n, err := conn.Read(buf)
if err != nil {
panic(err)
}
fmt.Printf("Received %d bytes\n", n)
}package main
import (
"fmt"
"net"
)
func main() {
ln, err := net.Listen("tcp", ":8092")
if err != nil {
panic(err)
}
defer ln.Close()
fmt.Println("Server listening on :8092")
conn, err := ln.Accept()
if err != nil {
panic(err)
}
defer conn.Close()
data := make([]byte, 4097)
for i := range data {
data[i] = byte(i % 256)
}
n, err := conn.Write(data)
if err != nil {
panic(err)
}
fmt.Printf("Sent %d bytes\n", n)
}In one shell run: tinygo build -target=wasip2 -o server.wasm tcp-server.go
wasmtime run -Sinherit-network server.wasmIn another shell run: go run tcp-client.goYou get this error: When running normally with I think the offending code is this part: https://github.com/tinygo-org/net/blob/043bd3f10e41db40d971bbc3bcffe10b8c186214/tcp_wasip2.go#L141C1-L141C57 It is essentially the same issue that I am having with printing larger data that I reported here: tinygo-org/tinygo#5012 Sorry if I am on the wrong track, new to WASM :) |
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@dgryski @ErikFrankling thanks for your feedback! Sorry for long delay. Here's the test program for TCP: PATH=$PATH:/tmp/wasm-tools-1.239.0-x86_64-linux:/tmp/binaryen-version_124/bin/ GOOS=wasip2 GOARCH=wasm /tmp/tinygo/build/tinygo build -o /tmp/srv.wasm /tmp/srv.go && WASMTIME_BACKTRACE_DETAILS=1 /tmp/wasmtime-v36.0.2-x86_64-linux/wasmtime run -S inherit-network=y,inherit-env=y,allow-ip-name-lookup=y /tmp/srv.wasmServerpackage main
import (
"fmt"
"net"
"slices"
)
func main() {
ln, err := net.Listen("tcp", ":8092")
if err != nil {
panic(err)
}
defer ln.Close()
fmt.Println("Server listening on :8092")
for {
conn, err := ln.Accept()
if err != nil {
panic(err)
}
defer conn.Close()
buf := make([]byte, 64*1024)
n, err := conn.Read(buf)
if err != nil {
panic(err)
}
fmt.Println(string(buf[:50]) + "...")
fmt.Println("..." + string(buf[n-50:n]))
fmt.Printf("Received %d bytes\n", n)
mirrored := buf[:n]
slices.Reverse(mirrored)
n, err = conn.Write(mirrored)
if err != nil {
panic(err)
}
fmt.Printf("Sent %d bytes\n", n)
}
}PATH=$PATH:/tmp/wasm-tools-1.239.0-x86_64-linux:/tmp/binaryen-version_124/bin/ GOOS=wasip2 GOARCH=wasm /tmp/tinygo/build/tinygo build -o /tmp/cl.wasm /tmp/cl.go && WASMTIME_BACKTRACE_DETAILS=1 /tmp/wasmtime-v36.0.2-x86_64-linux/wasmtime run -S inherit-network=y,inherit-env=y,allow-ip-name-lookup=y /tmp/cl.wasmClient - feel free to replace 12000 with sth less or more, e.g. 20 to send 61 bytes totalpackage main
import (
"fmt"
"net"
"strconv"
)
func main() {
conn, err := net.Dial("tcp", "localhost:8092")
if err != nil {
panic(err)
}
defer conn.Close()
str := "hello,"
for i := range 12000 {
str += strconv.Itoa(i) + ","
}
str += "world"
n, err := conn.Write([]byte(str))
if err != nil {
panic(err)
}
fmt.Printf("Sent %d bytes\n", n)
buf := make([]byte, 64*1024)
n, err = conn.Read(buf)
if err != nil {
panic(err)
}
fmt.Println(string(buf[:50]) + "...")
fmt.Println("..." + string(buf[n-50:n]))
fmt.Printf("Received %d bytes\n", n)
}Haven't touched the UDP part yet |
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| const ( | ||
| _AF_INET = 0x2 | ||
| _AF_INET6 = 0xA |
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Doesn't end up really used, nor did I test IPv6. Should we drop it for now?
