From 68e2fa2014e97a7aee4c0f6a6f85f342fe9155d2 Mon Sep 17 00:00:00 2001
From: Simone Basso <bassosimone@gmail.com>
Date: Sat, 23 Nov 2024 12:56:19 +0100
Subject: [PATCH] refactor(netsim): move most code inside netsim/netstack

The top-level package should contain more specific code handling
scenarios rather than the netstack stub network.

Let's make this possibly by moving the netstack into its own package.
---
 netsim/aliases.go                      | 24 ++++++++++++++++++++++++
 netsim/{ => link}/link.go              | 16 ++++++++--------
 netsim/{ => netstack}/addr.go          |  2 +-
 netsim/{ => netstack}/deadline.go      |  2 +-
 netsim/{ => netstack}/dialer.go        |  2 +-
 netsim/{ => netstack}/errno_unix.go    |  2 +-
 netsim/{ => netstack}/errno_windows.go |  2 +-
 netsim/{ => netstack}/packet.go        |  2 +-
 netsim/{ => netstack}/port.go          |  2 +-
 netsim/{ => netstack}/stack.go         |  6 +++---
 netsim/{ => netstack}/tcpconn.go       |  2 +-
 netsim/{ => netstack}/tcplistener.go   |  2 +-
 netsim/{ => netstack}/udpconn.go       |  2 +-
 13 files changed, 45 insertions(+), 21 deletions(-)
 create mode 100644 netsim/aliases.go
 rename netsim/{ => link}/link.go (81%)
 rename netsim/{ => netstack}/addr.go (97%)
 rename netsim/{ => netstack}/deadline.go (99%)
 rename netsim/{ => netstack}/dialer.go (98%)
 rename netsim/{ => netstack}/errno_unix.go (98%)
 rename netsim/{ => netstack}/errno_windows.go (98%)
 rename netsim/{ => netstack}/packet.go (96%)
 rename netsim/{ => netstack}/port.go (99%)
 rename netsim/{ => netstack}/stack.go (98%)
 rename netsim/{ => netstack}/tcpconn.go (99%)
 rename netsim/{ => netstack}/tcplistener.go (98%)
 rename netsim/{ => netstack}/udpconn.go (97%)

diff --git a/netsim/aliases.go b/netsim/aliases.go
new file mode 100644
index 0000000..1688e15
--- /dev/null
+++ b/netsim/aliases.go
@@ -0,0 +1,24 @@
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// Aliases
+//
+
+package netsim
+
+import (
+	"github.com/rbmk-project/x/netsim/link"
+	"github.com/rbmk-project/x/netsim/netstack"
+)
+
+// Stack is an alias for [netstack.Stack].
+type Stack = netstack.Stack
+
+// Link is an alias for [link.Link].
+type Link = link.Link
+
+// NewStack is an alias for [netstack.New].
+var NewStack = netstack.New
+
+// NewLink is an alias for [link.New].
+var NewLink = link.New
diff --git a/netsim/link.go b/netsim/link/link.go
similarity index 81%
rename from netsim/link.go
rename to netsim/link/link.go
index 0ec2b25..ca70be0 100644
--- a/netsim/link.go
+++ b/netsim/link/link.go
@@ -1,10 +1,7 @@
-//
 // SPDX-License-Identifier: GPL-3.0-or-later
-//
-// Packet and related definitions.
-//
 
-package netsim
+// Package link models a point-to-point network link.
+package link
 
 import (
 	"sync"
@@ -15,9 +12,12 @@ import (
 // LinkStack is the [*Stack] as seen by a [*Link].
 type LinkStack = packet.NetworkDevice
 
+// Packet is the [packet.Packet] alias used by this package.
+type Packet = packet.Packet
+
 // Link models a link between two [*Stack] instances.
 //
-// The zero value is not ready to use; construct using [NewLink].
+// The zero value is not ready to use; construct using [New].
 type Link struct {
 	// eof unblocks any blocking channel operation.
 	eof chan struct{}
@@ -26,10 +26,10 @@ type Link struct {
 	eofOnce sync.Once
 }
 
-// NewLink creates a new [*Link] using two [*Stack] and
+// New creates a new [*Link] using two [*Stack] and
 // sets up moving packets between the two stacks. Use Close
 // to shut down background goroutines.
-func NewLink(left, right LinkStack) *Link {
+func New(left, right LinkStack) *Link {
 	lnk := &Link{
 		eof:     make(chan struct{}),
 		eofOnce: sync.Once{},
diff --git a/netsim/addr.go b/netsim/netstack/addr.go
similarity index 97%
rename from netsim/addr.go
rename to netsim/netstack/addr.go
index 146da87..244f549 100644
--- a/netsim/addr.go
+++ b/netsim/netstack/addr.go
@@ -4,7 +4,7 @@
 // net.Addr implementation.
 //
 
-package netsim
+package netstack
 
 import (
 	"net"
diff --git a/netsim/deadline.go b/netsim/netstack/deadline.go
similarity index 99%
rename from netsim/deadline.go
rename to netsim/netstack/deadline.go
index a93d069..73b590f 100644
--- a/netsim/deadline.go
+++ b/netsim/netstack/deadline.go
@@ -6,7 +6,7 @@
 // Deadline management.
 //
 
-package netsim
+package netstack
 
 import (
 	"sync"
diff --git a/netsim/dialer.go b/netsim/netstack/dialer.go
similarity index 98%
rename from netsim/dialer.go
rename to netsim/netstack/dialer.go
index 2f89f64..b4e3778 100644
--- a/netsim/dialer.go
+++ b/netsim/netstack/dialer.go
@@ -4,7 +4,7 @@
 // Dialer implementation
 //
 
-package netsim
+package netstack
 
 import (
 	"context"
diff --git a/netsim/errno_unix.go b/netsim/netstack/errno_unix.go
similarity index 98%
rename from netsim/errno_unix.go
rename to netsim/netstack/errno_unix.go
index 610b0dd..444cd7c 100644
--- a/netsim/errno_unix.go
+++ b/netsim/netstack/errno_unix.go
@@ -6,7 +6,7 @@
 // UNIX errno definitions.
 //
 
-package netsim
+package netstack
 
 import "golang.org/x/sys/unix"
 
diff --git a/netsim/errno_windows.go b/netsim/netstack/errno_windows.go
similarity index 98%
rename from netsim/errno_windows.go
rename to netsim/netstack/errno_windows.go
index 79d047b..f78d7fa 100644
--- a/netsim/errno_windows.go
+++ b/netsim/netstack/errno_windows.go
@@ -6,7 +6,7 @@
 // Windows errno definitions.
 //
 
-package netsim
+package netstack
 
 import "golang.org/x/sys/windows"
 
diff --git a/netsim/packet.go b/netsim/netstack/packet.go
similarity index 96%
rename from netsim/packet.go
rename to netsim/netstack/packet.go
index 6014ab5..e26dcd4 100644
--- a/netsim/packet.go
+++ b/netsim/netstack/packet.go
@@ -4,7 +4,7 @@
 // Aliases for Packet and the related definitions.
 //
 
-package netsim
+package netstack
 
 import "github.com/rbmk-project/x/netsim/packet"
 
diff --git a/netsim/port.go b/netsim/netstack/port.go
similarity index 99%
rename from netsim/port.go
rename to netsim/netstack/port.go
index fd6dbeb..1eb235b 100644
--- a/netsim/port.go
+++ b/netsim/netstack/port.go
@@ -4,7 +4,7 @@
 // TCP/UDP port implementation.
 //
 
-package netsim
+package netstack
 
 import (
 	"fmt"
diff --git a/netsim/stack.go b/netsim/netstack/stack.go
similarity index 98%
rename from netsim/stack.go
rename to netsim/netstack/stack.go
index 77864ee..c268f3b 100644
--- a/netsim/stack.go
+++ b/netsim/netstack/stack.go
@@ -4,7 +4,7 @@
 // Network stack
 //
 
-package netsim
+package netstack
 
 import (
 	"context"
@@ -49,10 +49,10 @@ type Stack struct {
 	ports map[PortAddr]*Port
 }
 
-// NewStack creates a new [*Stack] instance and starts a
+// New creates a new [*Stack] instance and starts a
 // goroutine demuxing incoming traffic. Remember to invoke
 // Close to stop any muxing/demuxing goroutine.
-func NewStack(addrs ...netip.Addr) *Stack {
+func New(addrs ...netip.Addr) *Stack {
 	const (
 		// firstEphemeralPort is the first ephemeral port
 		// to use according to RFC6335.
diff --git a/netsim/tcpconn.go b/netsim/netstack/tcpconn.go
similarity index 99%
rename from netsim/tcpconn.go
rename to netsim/netstack/tcpconn.go
index 5ecc9e2..6940dc0 100644
--- a/netsim/tcpconn.go
+++ b/netsim/netstack/tcpconn.go
@@ -4,7 +4,7 @@
 // TCP Conn/PacketConn.
 //
 
-package netsim
+package netstack
 
 import (
 	"bytes"
diff --git a/netsim/tcplistener.go b/netsim/netstack/tcplistener.go
similarity index 98%
rename from netsim/tcplistener.go
rename to netsim/netstack/tcplistener.go
index 3c42364..6a0f230 100644
--- a/netsim/tcplistener.go
+++ b/netsim/netstack/tcplistener.go
@@ -4,7 +4,7 @@
 // TCP Listener/PacketListener.
 //
 
-package netsim
+package netstack
 
 import (
 	"net"
diff --git a/netsim/udpconn.go b/netsim/netstack/udpconn.go
similarity index 97%
rename from netsim/udpconn.go
rename to netsim/netstack/udpconn.go
index 8e62575..5a6a130 100644
--- a/netsim/udpconn.go
+++ b/netsim/netstack/udpconn.go
@@ -4,7 +4,7 @@
 // UDP Conn/PacketConn.
 //
 
-package netsim
+package netstack
 
 import "net"