From e52c5ec58ef644bc10ae2faaaa06e1512b76fa8f Mon Sep 17 00:00:00 2001
From: lash <dev@holbrook.no>
Date: Mon, 26 Nov 2018 23:58:24 +0100
Subject: [PATCH] swarm/pss: Rebase on master after kad depth change + handler
 refactor

---
 swarm/pss/pss.go | 69 +++++++++++++++++++++++++++++++++++-------------
 1 file changed, 50 insertions(+), 19 deletions(-)

diff --git a/swarm/pss/pss.go b/swarm/pss/pss.go
index d0986d280b..32bad6fbef 100644
--- a/swarm/pss/pss.go
+++ b/swarm/pss/pss.go
@@ -897,10 +897,38 @@ func (p *Pss) forward(msg *PssMsg) error {
 
 	// send with kademlia
 	// find the closest peer to the recipient and attempt to send
+
+	// number of sends performed. enables us to evaluate whether send was at all successful
 	sent := 0
-	p.Kademlia.EachConn(to, 256, func(sp *network.Peer, po int, isproxbin bool) bool {
+
+	// TODO: debug, remove in production
+	// calculate proximity to recipient address
+	ponow, _ := p.Kademlia.Pof(p.BaseAddr(), to, 0)
+
+	// The effective depth is the same as nearest neighbor depth OR
+	// the amount of address bytes in the neighbor, whichever is shallower
+	// this term aliasing has the effect of considering ALL connected peers
+	// who match the address prefix as nearest neighbors, and we will forward
+	// to all of them.
+	effectiveDepth := p.Kademlia.NeighbourhoodDepth()
+	darkRadius := len(msg.To) * 8
+	if darkRadius < addressLength*8 && effectiveDepth > darkRadius {
+		effectiveDepth = darkRadius
+	}
+
+	// Set to depth on the first successful send
+	cutoffDepth := 0
+
+	p.Kademlia.EachConn(to, addressLength*8, func(sp *network.Peer, po int, isproxbin bool) bool {
 		info := sp.Info()
 
+		// the cutoffDepth will be set after the first successful send.
+		// that means that before a send has been made OR the peer returned
+		// is still within the effective depth, we will pass through this check
+		if po < cutoffDepth {
+			return false
+		}
+
 		// check if the peer is running pss
 		var ispss bool
 		for _, cap := range info.Caps {
@@ -915,12 +943,18 @@ func (p *Pss) forward(msg *PssMsg) error {
 		}
 
 		// get the protocol peer from the forwarding peer cache
-		sendMsg := fmt.Sprintf("MSG TO %x FROM %x VIA %x", to, p.BaseAddr(), sp.Address())
 		p.fwdPoolMu.RLock()
 		pp := p.fwdPool[sp.Info().ID]
 		p.fwdPoolMu.RUnlock()
 
+		// TODO: debug, remove in production
+		// calculate proximity from returned kademlia peer to destination and log it
+		powill, _ := p.Kademlia.Pof(sp.Address(), to, 0)
+		log.Debug("forward", "topic", label(msg.Payload.Topic[:]), "self", label(p.BaseAddr()), "to", label(sp.Address()), "dest", label(to), "po", ponow, "advance", powill-ponow)
+		println(p.Kademlia.String())
+
 		// attempt to send the message
+		// short circuit to next iteration pass when it fails
 		err := pp.Send(context.TODO(), msg)
 		if err != nil {
 			metrics.GetOrRegisterCounter("pss.pp.send.error", nil).Inc(1)
@@ -928,26 +962,23 @@ func (p *Pss) forward(msg *PssMsg) error {
 			return true
 		}
 		sent++
-		log.Trace(fmt.Sprintf("%v: successfully forwarded", sendMsg))
-
-		// continue forwarding if:
-		// - if the peer is end recipient but the full address has not been disclosed
-		// - if the peer address matches the partial address fully
-		// - if the peer is in proxbin
-		if len(msg.To) < addressLength && bytes.Equal(msg.To, sp.Address()[:len(msg.To)]) {
-			log.Trace(fmt.Sprintf("Pss keep forwarding: Partial address + full partial match"))
-			return true
-		} else if isproxbin {
-			log.Trace(fmt.Sprintf("%x is in proxbin, keep forwarding", common.ToHex(sp.Address())))
-			return true
+
+		// If the po is at addresslength (TODO: how can it be greater?)
+		// it means that the peer address is identical to the message address
+		// and that peer must be  the final recipient
+		// further forwarding is thus not needed
+		if po >= addressLength*8 {
+			return false
 		}
-		// at this point we stop forwarding, and the state is as follows:
-		// - the peer is end recipient and we have full address
-		// - we are not in proxbin (directed routing)
-		// - partial addresses don't fully match
-		return false
+
+		// activate the cutoff when we have a successful send
+		if sent == 1 {
+			cutoffDepth = effectiveDepth
+		}
+		return true
 	})
 
+	// if we failed to send to anyone, re-insert message in the send-queue
 	if sent == 0 {
 		log.Debug("unable to forward to any peers")
 		if err := p.enqueue(msg); err != nil {