From 6bb159d5fa9953bd752c1217ab4dd625c8f60281 Mon Sep 17 00:00:00 2001
From: Naman Sood <mail@nsood.in>
Date: Wed, 21 Apr 2021 14:29:35 -0400
Subject: [PATCH] wgengine/netstack: log ForwarderRequest in readable form,
 only in debug mode

Fixes #1757

Signed-off-by: Naman Sood <mail@nsood.in>
---
 wgengine/netstack/netstack.go | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/wgengine/netstack/netstack.go b/wgengine/netstack/netstack.go
index b0fc6ea55..1fe70134b 100644
--- a/wgengine/netstack/netstack.go
+++ b/wgengine/netstack/netstack.go
@@ -393,12 +393,10 @@ func (ns *Impl) injectInbound(p *packet.Parsed, t *tstun.Wrapper) filter.Respons
 }
 
 func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
-	if debugNetstack {
-		// Kinda ugly:
-		// ForwarderRequest: &{{{{0 0}}} 0xc0001c30b0 0xc0004c3d40 {1240 6 true 826109390 0 true}
-		ns.logf("[v2] ForwarderRequest: %v", r)
-	}
 	reqDetails := r.ID()
+	if debugNetstack {
+		ns.logf("[v2] TCP ForwarderRequest: %s", stringifyTEI(reqDetails))
+	}
 	dialAddr := reqDetails.LocalAddress
 	dialNetAddr, _ := netaddr.FromStdIP(net.IP(dialAddr))
 	isTailscaleIP := tsaddr.IsTailscaleIP(dialNetAddr)
@@ -472,7 +470,10 @@ func (ns *Impl) forwardTCP(client *gonet.TCPConn, wq *waiter.Queue, dialAddr tcp
 }
 
 func (ns *Impl) acceptUDP(r *udp.ForwarderRequest) {
-	ns.logf("[v2] UDP ForwarderRequest: %v", r)
+	reqDetails := r.ID()
+	if debugNetstack {
+		ns.logf("[v2] UDP ForwarderRequest: %v", stringifyTEI(reqDetails))
+	}
 	var wq waiter.Queue
 	ep, err := r.CreateEndpoint(&wq)
 	if err != nil {
@@ -563,3 +564,7 @@ func startPacketCopy(ctx context.Context, cancel context.CancelFunc, dst net.Pac
 		}
 	}()
 }
+
+func stringifyTEI(tei stack.TransportEndpointID) string {
+	return fmt.Sprintf("%s:%v -> %s:%v", tei.LocalAddress, tei.LocalPort, tei.RemoteAddress, tei.RemotePort)
+}