Allow User to provide Address and Port for Client to use.

[cloakwiss]

Client uses randomly picked port and address (not actually random), but in some cases it helps if the client uses a given address and port.
For example, when server has no public address and both client and server are behind several layer of (stateful) firewalls.
Some kind of hole punching mechanism is needed (in my case 2 devices simultaneously sending UDP packet towards each other), before the application (client and servers) are started.

[termermc]

You can set up listening ports manually in the client's peer settings page. Are you saying that you should be able to set a specific port for hole punching and not just normal peer connections?

[termermc]

Also, if the server doesn't have a public address and can't help with STUN, you can specify alternative STUN servers in the server config to send to clients to use, like Google's or Cloudflare's public STUN endpoints.

Out of curiosity, how are you connecting to the server without a public address? Are you using Yggdrasil or some other overlay network?

[cloakwiss]

Well I am running the server (and client with file share) on my laptop and my friend has the client and together (and at same time) we do something like this UDP Peer to Peer Connection with Netcat using application which I made Upunching.
As you pointed out listening ports can be configured in client's page but it will only be useful after client has connected with server.

[termermc]

There are multiple connections involved in FriendNet:

• Client to server
• then, client to client

Client to client direct connections already have NAT holepunching built in on a random port, but I could possibly make that happen on a user-configurable stable port. Is that what you're asking?

Or, do you need the client to bind to a specific port when connecting to the server? That's also possible and could be configured per-server.

I'm not sure I'm understanding what you need.

[cloakwiss]

Yes I need client to bind to a specific port and also address (since each computer might have multiple IP address and also multiple IPv6 addresses) via a command line flag to client similar to -davaddr string flag and it should use that address and port for everything it does.

I have a patch to make it work for me, but it is not good enough because in case the server is not listening to both IPv4 and IPv6 the user might need to pass both addresses

[termermc]

I could do that. Does it need to already be bound to the addrport, or can it bind when it connects? I'm thinking this could be an extra option when creating/editing a server.

[termermc]

If you're willing to share your patch, I could use that to confirm I'm doing it in a way that works for your setup.

[cloakwiss]

I could do that. Does it need to already be bound to the addrport, or can it bind when it connects? I'm thinking this could be an extra option when creating/editing a server.

I am not sure about it that is why I created this issue.

[cloakwiss]

diff --git a/client/cmd/client/main.go b/client/cmd/client/main.go
index 8b38d10c7f..6d08c9ecf0 100644
--- a/client/cmd/client/main.go
+++ b/client/cmd/client/main.go
@@ -8,9 +8,11 @@
 	"errors"
 	"flag"
 	"fmt"
+	"log"
 	"log/slog"
 	"net"
 	"net/http"
+	"net/netip"
 	"net/url"
 	"os"
 	"os/signal"
@@ -122,7 +124,9 @@
 	var resetToken bool
 	var pprofFile string
 	var rmCertHost string
+	var chosenSocket string
 
+	flag.StringVar(&chosenSocket, "localsocket", "", "use this address (with port & without protocol) to communicate with server")
 	flag.StringVar(&dataDir, "datadir", "", "path to the client's data directory")
 	flag.StringVar(&webAddr, "webaddr", "http://127.0.0.1:20042", "web UI and RPC address")
 	flag.StringVar(&davAddr, "davaddr", "http://127.0.0.1:20043", "WebDAV server address")
@@ -156,6 +160,20 @@
 		println("Running profiler, writing data to " + pprofFile)
 	}
 
+	var laddr net.UDPAddr = net.UDPAddr{IP: nil, Port: 0}
+	if chosenSocket != "" {
+		ipnp, err := netip.ParseAddrPort(chosenSocket)
+		if err != nil {
+			panic(fmt.Errorf(`cannot parse the local addres provided: %w`, err))
+		}
+		if ipnp.Addr().Is6() {
+			ip := ipnp.Addr().As16()
+			laddr = net.UDPAddr{IP: ip[:], Port: int(ipnp.Port())}
+		} else {
+			log.Panicln("Dont need this at the moment")
+		}
+	}
+
 	if headless {
 		noBrowser = true
 		noLock = true
@@ -310,6 +328,7 @@
 		connMethodSupport,
 		directMgr,
 		eventBus,
+		laddr,
 	)
 	if err != nil {
 		panic(fmt.Errorf(`failed to create multi client: %w`, err))
diff --git a/client/multi.go b/client/multi.go
index 282cb2aaf0..6da643c6ba 100644
--- a/client/multi.go
+++ b/client/multi.go
@@ -5,6 +5,7 @@
 	"errors"
 	"fmt"
 	"log/slog"
+	"net"
 	"sync"
 	"time"
 
@@ -62,6 +63,9 @@
 
 	// Mapping of server UUIDs to the Server instances that manage connections to them.
 	servers map[string]*Server
+
+	// This is my new addition
+	localSocket net.UDPAddr
 }
 
 // NewMultiClient creates a new MultiClient instance.
@@ -73,6 +77,7 @@
 	connMethodSupport machine.ConnMethodSupport,
 	directMgr *direct.Manager,
 	eventBus *event.Bus,
+	localSocket net.UDPAddr,
 ) (*MultiClient, error) {
 	ctx, ctxCancel := context.WithCancel(context.Background())
 
@@ -92,6 +97,7 @@
 		directMgr:         directMgr,
 		eventBus:          eventBus,
 		servers:           make(map[string]*Server, len(serverRecs)),
+		localSocket:       localSocket,
 	}
 
 	for _, record := range serverRecs {
@@ -194,6 +200,7 @@
 			c.eventBus.CreatePublisher(&v1.EventContext{
 				ServerUuid: record.Uuid,
 			}),
+			c.localSocket,
 			record.Address,
 			room.Credentials{
 				Room:     record.Room,
diff --git a/client/nanny.go b/client/nanny.go
index d31d96f2bc..f3111e62b6 100644
--- a/client/nanny.go
+++ b/client/nanny.go
@@ -4,6 +4,7 @@
 	"context"
 	"errors"
 	"log/slog"
+	"net"
 	"runtime/debug"
 	"sync"
 	"time"
@@ -75,6 +76,8 @@
 	backoffWaker context.CancelFunc
 
 	state ConnState
+
+	localSocket net.UDPAddr
 }
 
 // NewConnNanny creates a new ConnNanny with the specified server address and credentials.
@@ -91,6 +94,7 @@
 	directMgr *direct.Manager,
 	directPartitionName string,
 	eventPublisher *event.Publisher,
+	localSocket net.UDPAddr,
 	address string,
 	creds room.Credentials,
 	logic room.Logic,
@@ -122,6 +126,8 @@
 		backoffWaker: func() {},
 
 		state: ConnStateClosed,
+
+		localSocket: localSocket,
 	}
 
 	go n.daemon()
@@ -323,6 +329,7 @@
 			n.directMgr,
 			n.directPartName,
 			n.eventPublisher,
+			n.localSocket,
 			n.address,
 			n.creds,
 		)
diff --git a/client/room/conn.go b/client/room/conn.go
index 058320905f..3e43cde3d9 100644
--- a/client/room/conn.go
+++ b/client/room/conn.go
@@ -213,13 +213,14 @@
 	directMgr *direct.Manager,
 	directPartitionName string,
 	eventPublisher *event.Publisher,
+	localSocket net.UDPAddr,
 	address string,
 	creds Credentials,
 ) (*Conn, error) {
 	clientVer := protocol.CurrentProtocolVersion
 
 	ctx, ctxCancel := context.WithCancel(context.Background())
-	conn, err := ConnectWithCertStore(ctx, certStore, address)
+	conn, err := ConnectWithCertStore(ctx, localSocket, certStore, address)
 	if err != nil {
 		ctxCancel()
 		return nil, err
diff --git a/client/room/connector.go b/client/room/connector.go
index b83dd098c7..9f4f6b221d 100644
--- a/client/room/connector.go
+++ b/client/room/connector.go
@@ -21,7 +21,7 @@
 //   - protocol.ErrNoServerCerts: Server returned no certs.
 //   - protocol.ErrServerCertNotValidNow: Server certificate is not valid at the current time.
 //   - protocol.CertMismatchError: Server returned a certificate that is different from the one associated with the hostname in the cert.Store.
-func ConnectWithCertStore(ctx context.Context, certStore cert.Store, address string) (protocol.ProtoConn, error) {
+func ConnectWithCertStore(ctx context.Context, localSocket net.UDPAddr, certStore cert.Store, address string) (protocol.ProtoConn, error) {
 	hostname, _, parseErr := net.SplitHostPort(address)
 	if parseErr != nil {
 		return nil, fmt.Errorf(`failed to parse address %q in ConnectWithCertStore: %w`, address, parseErr)
@@ -69,7 +69,17 @@
 		},
 	}
 
-	qConn, err := quic.DialAddr(ctx, address, tlsCfg, &quic.Config{
+	localUDPConn, err := net.ListenUDP("udp", &localSocket)
+	if err != nil {
+		return nil, fmt.Errorf(`failed to get for socket %q connect: %w`, &localSocket, err)
+	}
+
+	udpAddr, err := net.ResolveUDPAddr("udp", address)
+	if err != nil {
+		return nil, fmt.Errorf("failed to convert address from string to native address type %q: %w", address, err)
+	}
+
+	qConn, err := quic.Dial(ctx, localUDPConn, udpAddr, tlsCfg, &quic.Config{
 		KeepAlivePeriod:    protocol.DefaultKeepAlivePeriod,
 		MaxIncomingStreams: protocol.DefaultMaxIncomingStreams,
 	})

[termermc]

Cool, I'll include this feature in the next minor release.

[termermc]

I finally got some free time to work on this, it should be done this week. Thanks for your patience.

[cloakwiss]

After creating the issue (and showing you my patch) I realized that it worked by sheer luck in my case and
to properly do it, it would require a big change in client's design.
Thank you, for prioritizing my feature request and Sorry I cannot be of any help.

[termermc]

After creating the issue (and showing you my patch) I realized that it worked by sheer luck in my case and to properly do it, it would require a big change in client's design. Thank you, for prioritizing my feature request and Sorry I cannot be of any help.

I don't think it would be that bad. My plan is to just have an optional field for the bind address of the client to server connection, similar to how Bittorrent clients let you choose the interface to bind on. I think I'll also allow you to specify the interface.