From 14843b9e8916ef6a22279c993dc1122070140882 Mon Sep 17 00:00:00 2001
From: Justin Li <jli.justinli@gmail.com>
Date: Wed, 23 Jul 2014 13:08:52 -0400
Subject: [PATCH] Add AllowIPSpoofing configuration

---
 config/config.go    |  2 ++
 example.json        |  1 +
 http/query/query.go | 26 ++++++++++++++------------
 http/tracker.go     |  2 +-
 http/writer.go      |  2 +-
 5 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/config/config.go b/config/config.go
index 60b7b9c..58d422f 100644
--- a/config/config.go
+++ b/config/config.go
@@ -50,6 +50,7 @@ type Config struct {
 	Freeleech             bool `json:"freeleech"`
 	Whitelist             bool `json:"whitelist"`
 	PurgeInactiveTorrents bool `json:"purge_inactive_torrents"`
+	AllowIPSpoofing       bool `json:"allow_ip_spoofing"`
 
 	Announce        Duration `json:"announce"`
 	MinAnnounce     Duration `json:"min_announce"`
@@ -77,6 +78,7 @@ var DefaultConfig = Config{
 	Freeleech:             false,
 	Whitelist:             false,
 	PurgeInactiveTorrents: true,
+	AllowIPSpoofing:       true,
 
 	Announce:        Duration{30 * time.Minute},
 	MinAnnounce:     Duration{15 * time.Minute},
diff --git a/example.json b/example.json
index 802e658..103abac 100644
--- a/example.json
+++ b/example.json
@@ -14,6 +14,7 @@
   "freeleech": false,
   "whitelist": false,
   "purge_inactive_torrents": true,
+  "allow_ip_spoofing": true,
 
   "announce": "30m",
   "min_announce": "15m",
diff --git a/http/query/query.go b/http/query/query.go
index 973afd1..793d9b3 100644
--- a/http/query/query.go
+++ b/http/query/query.go
@@ -122,22 +122,24 @@ func (q Query) RequestedPeerCount(fallback int) int {
 }
 
 // RequestedIP returns the requested IP address from a Query.
-func (q Query) RequestedIP(r *http.Request) (net.IP, error) {
-	if ipstr, ok := q.Params["ip"]; ok {
-		if ip := net.ParseIP(ipstr); ip != nil {
-			return ip, nil
+func (q Query) RequestedIP(r *http.Request, allowSpoofing bool) (net.IP, error) {
+	if allowSpoofing {
+		if ipstr, ok := q.Params["ip"]; ok {
+			if ip := net.ParseIP(ipstr); ip != nil {
+				return ip, nil
+			}
 		}
-	}
 
-	if ipstr, ok := q.Params["ipv4"]; ok {
-		if ip := net.ParseIP(ipstr); ip != nil {
-			return ip, nil
+		if ipstr, ok := q.Params["ipv4"]; ok {
+			if ip := net.ParseIP(ipstr); ip != nil {
+				return ip, nil
+			}
 		}
-	}
 
-	if ipstr, ok := q.Params["ipv6"]; ok {
-		if ip := net.ParseIP(ipstr); ip != nil {
-			return ip, nil
+		if ipstr, ok := q.Params["ipv6"]; ok {
+			if ip := net.ParseIP(ipstr); ip != nil {
+				return ip, nil
+			}
 		}
 	}
 
diff --git a/http/tracker.go b/http/tracker.go
index 3762bc9..fafe6b7 100644
--- a/http/tracker.go
+++ b/http/tracker.go
@@ -35,7 +35,7 @@ func NewAnnounce(cfg *config.Config, r *http.Request, p httprouter.Params) (*mod
 		return nil, models.ErrMalformedRequest
 	}
 
-	ip, err := q.RequestedIP(r)
+	ip, err := q.RequestedIP(r, cfg.AllowIPSpoofing)
 	if err != nil {
 		return nil, models.ErrMalformedRequest
 	}
diff --git a/http/writer.go b/http/writer.go
index 66a179d..8cce11c 100644
--- a/http/writer.go
+++ b/http/writer.go
@@ -48,7 +48,7 @@ func (w *Writer) WriteAnnounce(res *models.AnnounceResponse) error {
 			}
 		}
 	} else if res.IPv4Peers != nil || res.IPv6Peers != nil {
-		dict["peers"] = peersList(res.IPv6Peers, res.IPv4Peers)
+		dict["peers"] = peersList(res.IPv4Peers, res.IPv6Peers)
 	}
 
 	bencoder := bencode.NewEncoder(w)