add public RemoveAddress API

after discussion with @ebuchman (#10 (comment))

addrbook.go

@@ -248,15 +248,21 @@ func (a *AddrBook) MarkAttempt(addr *NetAddress) {
 	ka.markAttempt()
 }
 
+// MarkBad currently just ejects the address. In the future, consider
+// blacklisting.
 func (a *AddrBook) MarkBad(addr *NetAddress) {
+	a.RemoveAddress(addr)
+}
+
+// RemoveAddress removes the address from the book.
+func (a *AddrBook) RemoveAddress(addr *NetAddress) {
 	a.mtx.Lock()
 	defer a.mtx.Unlock()
 	ka := a.addrLookup[addr.String()]
 	if ka == nil {
 		return
 	}
-	// We currently just eject the address.
-	// In the future, consider blacklisting.
+	log.Info("Remove address from book", "addr", addr)
 	a.removeFromAllBuckets(ka)
 }
 

addrbook_test.go

@@ -5,6 +5,8 @@ import (
 	"io/ioutil"
 	"math/rand"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 const addrBookStrict = true
@@ -161,3 +163,19 @@ func TestPromoteToOld(t *testing.T) {
 	selection := book.GetSelection()
 	t.Logf("selection: %v", selection)
 }
+
+func TestAddrBookRemoveAddress(t *testing.T) {
+	fname := createTempFileName("addrbook_test")
+	book := NewAddrBook(fname, true)
+
+	addr := randIPv4Address()
+	book.AddAddress(addr, addr)
+	assert.Equal(t, 1, book.Size())
+
+	book.RemoveAddress(addr)
+	assert.Equal(t, 0, book.Size())
+
+	nonExistingAddr := randIPv4Address()
+	book.RemoveAddress(nonExistingAddr)
+	assert.Equal(t, 0, book.Size())
+}

pex_reactor.go

@@ -102,10 +102,14 @@ func (r *PEXReactor) AddPeer(p *Peer) {
 }
 
 // RemovePeer implements Reactor by removing peer from the address book.
+//
+// The peer will be proposed to us by other peers (PexAddrsMessage) or himself
+// and we will add him again upon successful connection. Note that other peers
+// will remove him too. The peer will need to send first requests to others by
+// himself (he will have an addrbook or the seeds).
 func (r *PEXReactor) RemovePeer(p *Peer, reason interface{}) {
 	addr := NewNetAddressString(p.ListenAddr)
-	// addr will be ejected from the book
-	r.book.MarkBad(addr)
+	r.book.RemoveAddress(addr)
 }
 
 // Receive implements Reactor by handling incoming PEX messages.