From abd8b69979eb846dc12b6b7bcea51aebdf8065f4 Mon Sep 17 00:00:00 2001
From: Arceliar <Arceliar@users.noreply.github.com>
Date: Fri, 14 Dec 2018 18:15:35 -0600
Subject: [PATCH] send a switch message immediately when peering, and use
 OS-level TCP keep-alive (shouldn't matter right now, since we have
 application-level keep-alive that preempts it, but important later)

---
 src/yggdrasil/peer.go |  9 ++++-----
 src/yggdrasil/tcp.go  | 24 +++++++++++++++---------
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/yggdrasil/peer.go b/src/yggdrasil/peer.go
index 67aa805a..e092513b 100644
--- a/src/yggdrasil/peer.go
+++ b/src/yggdrasil/peer.go
@@ -177,6 +177,7 @@ func (p *peer) doSendSwitchMsgs() {
 func (p *peer) linkLoop() {
 	tick := time.NewTicker(time.Second)
 	defer tick.Stop()
+	p.doSendSwitchMsgs()
 	for {
 		select {
 		case _, ok := <-p.doSend:
@@ -185,11 +186,9 @@ func (p *peer) linkLoop() {
 			}
 			p.sendSwitchMsg()
 		case _ = <-tick.C:
-			//break             // FIXME disabled the below completely to test something
-			pdinfo := p.dinfo // FIXME this is a bad workarond NPE on the next line
-			if pdinfo != nil {
-				dinfo := *pdinfo
-				p.core.dht.peers <- &dinfo
+			dinfo := p.dinfo // FIXME? are pointer reads *always* atomic?
+			if dinfo != nil {
+				p.core.dht.peers <- dinfo
 			}
 		}
 	}
diff --git a/src/yggdrasil/tcp.go b/src/yggdrasil/tcp.go
index 5ca66304..5d4bfc71 100644
--- a/src/yggdrasil/tcp.go
+++ b/src/yggdrasil/tcp.go
@@ -31,14 +31,6 @@ const tcp_msgSize = 2048 + 65535 // TODO figure out what makes sense
 const default_tcp_timeout = 6 * time.Second
 const tcp_ping_interval = (default_tcp_timeout * 2 / 3)
 
-// Wrapper function for non tcp/ip connections.
-func setNoDelay(c net.Conn, delay bool) {
-	tcp, ok := c.(*net.TCPConn)
-	if ok {
-		tcp.SetNoDelay(delay)
-	}
-}
-
 // The TCP listener and information about active TCP connections, to avoid duplication.
 type tcpInterface struct {
 	core        *Core
@@ -58,6 +50,20 @@ type tcpInfo struct {
 	remoteAddr string
 }
 
+// Wrapper function to set additional options for specific connection types.
+func (iface *tcpInterface) setExtraOptions(c net.Conn) {
+	switch sock := c.(type) {
+	case *net.TCPConn:
+		sock.SetNoDelay(true)
+		sock.SetKeepAlive(true)
+		sock.SetKeepAlivePeriod(iface.tcp_timeout)
+		panic("DEBUG testing")
+	// TODO something for socks5
+	default:
+		iface.core.log.Println("Unrecognized connection type: %v", sock)
+	}
+}
+
 // Returns the address of the listener.
 func (iface *tcpInterface) getAddr() *net.TCPAddr {
 	return iface.serv.Addr().(*net.TCPAddr)
@@ -205,6 +211,7 @@ func (iface *tcpInterface) call(saddr string, socksaddr *string, sintf string) {
 // It defers a bunch of cleanup stuff to tear down all of these things when the reader exists (e.g. due to a closed connection or a timeout).
 func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 	defer sock.Close()
+	iface.setExtraOptions(sock)
 	// Get our keys
 	myLinkPub, myLinkPriv := newBoxKeys() // ephemeral link keys
 	meta := version_getBaseMetadata()
@@ -342,7 +349,6 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 		out <- msg
 	}
 	p.close = func() { sock.Close() }
-	setNoDelay(sock, true)
 	go p.linkLoop()
 	defer func() {
 		// Put all of our cleanup here...