Create IPPROTO_NONE alias & Add test for Unix socket (#24139)

closes #24116

lib/pure/nativesockets.nim

@@ -97,6 +97,8 @@ type
     length*: int
     addrList*: seq[string]
 
+const IPPROTO_NONE* = IPPROTO_IP ## Use this if your socket type requires a protocol value of zero (e.g. Unix sockets).
+
 when useWinVersion:
   let
     osInvalidSocket* = winlean.INVALID_SOCKET

lib/pure/net.nim

@@ -97,7 +97,7 @@ import std/nativesockets
 import std/[os, strutils, times, sets, options, monotimes]
 import std/ssl_config
 export nativesockets.Port, nativesockets.`$`, nativesockets.`==`
-export Domain, SockType, Protocol
+export Domain, SockType, Protocol, IPPROTO_NONE
 
 const useWinVersion = defined(windows) or defined(nimdoc)
 const useNimNetLite = defined(nimNetLite) or defined(freertos) or defined(zephyr) or

tests/stdlib/tunixsocket.nim

@@ -0,0 +1,35 @@
+import std/[assertions, net, os, osproc]
+
+# XXX: Make this test run on Windows too when we add support for Unix sockets on Windows
+when defined(posix) and not defined(nimNetLite):
+  const nim = getCurrentCompilerExe()
+  let
+    dir = currentSourcePath().parentDir()
+    serverPath = dir / "unixsockettest"
+
+  let (_, err) = execCmdEx(nim & " c " & quoteShell(dir / "unixsockettest.nim"))
+  doAssert err == 0
+
+  let svproc = startProcess(serverPath, workingDir = dir)
+  doAssert svproc.running()
+  # Wait for the server to open the socket and listen from it
+  sleep(400)
+
+  block unixSocketSendRecv:
+    let
+      unixSocketPath = dir / "usox"
+      socket = newSocket(AF_UNIX, SOCK_STREAM, IPPROTO_NONE)
+
+    socket.connectUnix(unixSocketPath)
+    # for a blocking Unix socket this should never fail
+    socket.send("data sent through the socket\c\l", maxRetries = 0)
+    var resp: string
+    socket.readLine(resp)
+    doAssert resp == "Hello from server"
+
+    socket.send("bye\c\l")
+    socket.readLine(resp)
+    doAssert resp == "bye"
+    socket.close()
+
+  svproc.close()

tests/stdlib/unixsockettest.nim

@@ -0,0 +1,26 @@
+import std/[assertions, net, os]
+
+let unixSocketPath = getCurrentDir() / "usox"
+
+removeFile(unixSocketPath)
+
+let socket = newSocket(AF_UNIX, SOCK_STREAM, IPPROTO_NONE)
+socket.bindUnix(unixSocketPath)
+socket.listen()
+
+var
+  clientSocket: Socket
+  data: string
+
+socket.accept(clientSocket)
+clientSocket.readLine(data)
+doAssert data == "data sent through the socket"
+clientSocket.send("Hello from server\c\l")
+
+clientSocket.readLine(data)
+doAssert data == "bye"
+clientSocket.send("bye\c\l")
+
+clientSocket.close()
+socket.close()
+removeFile(unixSocketPath)