From de5e56efde8f5ae0fc043fe4fd1717b44af80313 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Thu, 27 Jun 2019 16:28:09 +0200
Subject: [PATCH] fix: check for blocked addrs without allocating

---
 filter.go | 31 +++++++++++++++++++------------
 go.mod    |  5 +----
 go.sum    |  4 ----
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/filter.go b/filter.go
index a555df5..4eb0c56 100644
--- a/filter.go
+++ b/filter.go
@@ -5,7 +5,6 @@ import (
 	"sync"
 
 	ma "github.com/multiformats/go-multiaddr"
-	manet "github.com/multiformats/go-multiaddr-net"
 )
 
 // Action is an enum modelling all possible filter actions.
@@ -112,17 +111,25 @@ func (fs *Filters) RemoveLiteral(ipnet net.IPNet) (removed bool) {
 //  Instead, the highest-specific last filter should win; that way more specific filters
 //  override more general ones.
 func (fs *Filters) AddrBlocked(a ma.Multiaddr) (deny bool) {
-	maddr := ma.Split(a)
-	if len(maddr) == 0 {
-		return fs.DefaultAction == ActionDeny
-	}
-	netaddr, err := manet.ToNetAddr(maddr[0])
-	if err != nil {
-		// if we can't parse it, it's probably not blocked.
-		return fs.DefaultAction == ActionDeny
-	}
-	netip := net.ParseIP(netaddr.String())
-	if netip == nil {
+	var (
+		netip net.IP
+		found bool
+	)
+
+	ma.ForEach(a, func(c ma.Component) bool {
+		switch c.Protocol().Code {
+		case ma.P_IP6ZONE:
+			return true
+		case ma.P_IP6, ma.P_IP4:
+			found = true
+			netip = net.IP(c.RawValue())
+			return false
+		default:
+			return false
+		}
+	})
+
+	if !found {
 		return fs.DefaultAction == ActionDeny
 	}
 
diff --git a/go.mod b/go.mod
index 4adb057..4e46b65 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,3 @@
 module github.com/libp2p/go-maddr-filter
 
-require (
-	github.com/multiformats/go-multiaddr v0.0.1
-	github.com/multiformats/go-multiaddr-net v0.0.1
-)
+require github.com/multiformats/go-multiaddr v0.0.1
diff --git a/go.sum b/go.sum
index 11cfae5..cbf49eb 100644
--- a/go.sum
+++ b/go.sum
@@ -10,10 +10,6 @@ github.com/mr-tron/base58 v1.1.0 h1:Y51FGVJ91WBqCEabAi5OPUz38eAx8DakuAm5svLcsfQ=
 github.com/mr-tron/base58 v1.1.0/go.mod h1:xcD2VGqlgYjBdcBLw+TuYLr8afG+Hj8g2eTVqeSzSU8=
 github.com/multiformats/go-multiaddr v0.0.1 h1:/QUV3VBMDI6pi6xfiw7lr6xhDWWvQKn9udPn68kLSdY=
 github.com/multiformats/go-multiaddr v0.0.1/go.mod h1:xKVEak1K9cS1VdmPZW3LSIb6lgmoS58qz/pzqmAxV44=
-github.com/multiformats/go-multiaddr-dns v0.0.1 h1:jQt9c6tDSdQLIlBo4tXYx7QUHCPjxsB1zXcag/2S7zc=
-github.com/multiformats/go-multiaddr-dns v0.0.1/go.mod h1:9kWcqw/Pj6FwxAwW38n/9403szc57zJPs45fmnznu3Q=
-github.com/multiformats/go-multiaddr-net v0.0.1 h1:76O59E3FavvHqNg7jvzWzsPSW5JSi/ek0E4eiDVbg9g=
-github.com/multiformats/go-multiaddr-net v0.0.1/go.mod h1:nw6HSxNmCIQH27XPGBuX+d1tnvM7ihcFwHMSstNAVUU=
 github.com/multiformats/go-multihash v0.0.1 h1:HHwN1K12I+XllBCrqKnhX949Orn4oawPkegHMu2vDqQ=
 github.com/multiformats/go-multihash v0.0.1/go.mod h1:w/5tugSrLEbWqlcgJabL3oHFKTwfvkofsjW2Qa1ct4U=
 golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67 h1:ng3VDlRp5/DHpSWl02R4rM9I+8M2rhmsuLwAMmkLQWE=