From c8e8b95bfe4892f04ec3ffa5ad04c1df569c00d4 Mon Sep 17 00:00:00 2001
From: Jimmy Zelinskie <jimmyzelinskie@gmail.com>
Date: Thu, 20 Aug 2015 00:17:00 -0400
Subject: [PATCH] http: stop using remote http port

The remote port used to send the announce has nothing to do with the
port being listened to for the torrent client protocol.
---
 http/tracker.go | 52 ++++++++++++++++---------------------------------
 1 file changed, 17 insertions(+), 35 deletions(-)

diff --git a/http/tracker.go b/http/tracker.go
index 6e7e95d..ef0d64e 100644
--- a/http/tracker.go
+++ b/http/tracker.go
@@ -44,32 +44,18 @@ func (s *Server) newAnnounce(r *http.Request, p httprouter.Params) (*models.Anno
 	}
 
 	left, err := q.Uint64("left")
-
-	ipv4, ipv6, err := requestedEndpoint(q, r, &s.config.NetConfig)
 	if err != nil {
 		return nil, models.ErrMalformedRequest
 	}
 
-	var ipv4Endpoint, ipv6Endpoint models.Endpoint
-	if ipv4 != nil {
-		ipv4Endpoint = *ipv4
-		// If the port we couldn't get the port before, fallback to the port param.
-		if ipv4Endpoint.Port == uint16(0) {
-			ipv4Endpoint.Port = uint16(port)
-		}
-	}
-	if ipv6 != nil {
-		ipv6Endpoint = *ipv6
-		// If the port we couldn't get the port before, fallback to the port param.
-		if ipv6Endpoint.Port == uint16(0) {
-			ipv6Endpoint.Port = uint16(port)
-		}
-	}
-
+	ipv4, ipv6, err := requestedIP(q, r, &s.config.NetConfig)
 	if err != nil {
 		return nil, models.ErrMalformedRequest
 	}
 
+	ipv4Endpoint := models.Endpoint{ipv4, uint16(port)}
+	ipv6Endpoint := models.Endpoint{ipv6, uint16(port)}
+
 	downloaded, err := q.Uint64("downloaded")
 	if err != nil {
 		return nil, models.ErrMalformedRequest
@@ -132,26 +118,26 @@ func requestedPeerCount(q *query.Query, fallback int) int {
 	return fallback
 }
 
-// requestedEndpoint returns the IP address and port pairs for a request. If
-// there are multiple in the request, one IPv4 and one IPv6 will be returned.
-func requestedEndpoint(q *query.Query, r *http.Request, cfg *config.NetConfig) (v4, v6 *models.Endpoint, err error) {
+// requestedIP returns the IP address for a request. If there are multiple in
+// the request, one IPv4 and one IPv6 will be returned.
+func requestedIP(q *query.Query, r *http.Request, cfg *config.NetConfig) (v4, v6 net.IP, err error) {
 	var done bool
 
 	if cfg.AllowIPSpoofing {
 		if str, ok := q.Params["ip"]; ok {
-			if v4, v6, done = getEndpoints(str, v4, v6, cfg); done {
+			if v4, v6, done = getIPs(str, v4, v6, cfg); done {
 				return
 			}
 		}
 
 		if str, ok := q.Params["ipv4"]; ok {
-			if v4, v6, done = getEndpoints(str, v4, v6, cfg); done {
+			if v4, v6, done = getIPs(str, v4, v6, cfg); done {
 				return
 			}
 		}
 
 		if str, ok := q.Params["ipv6"]; ok {
-			if v4, v6, done = getEndpoints(str, v4, v6, cfg); done {
+			if v4, v6, done = getIPs(str, v4, v6, cfg); done {
 				return
 			}
 		}
@@ -159,18 +145,18 @@ func requestedEndpoint(q *query.Query, r *http.Request, cfg *config.NetConfig) (
 
 	if cfg.RealIPHeader != "" {
 		if xRealIPs, ok := r.Header[cfg.RealIPHeader]; ok {
-			if v4, v6, done = getEndpoints(string(xRealIPs[0]), v4, v6, cfg); done {
+			if v4, v6, done = getIPs(string(xRealIPs[0]), v4, v6, cfg); done {
 				return
 			}
 		}
 	} else {
 		if r.RemoteAddr == "" && v4 == nil {
-			if v4, v6, done = getEndpoints("127.0.0.1", v4, v6, cfg); done {
+			if v4, v6, done = getIPs("127.0.0.1", v4, v6, cfg); done {
 				return
 			}
 		}
 
-		if v4, v6, done = getEndpoints(r.RemoteAddr, v4, v6, cfg); done {
+		if v4, v6, done = getIPs(r.RemoteAddr, v4, v6, cfg); done {
 			return
 		}
 	}
@@ -182,22 +168,18 @@ func requestedEndpoint(q *query.Query, r *http.Request, cfg *config.NetConfig) (
 	return
 }
 
-func getEndpoints(ipstr string, ipv4, ipv6 *models.Endpoint, cfg *config.NetConfig) (*models.Endpoint, *models.Endpoint, bool) {
-	host, port, err := net.SplitHostPort(ipstr)
+func getIPs(ipstr string, ipv4, ipv6 net.IP, cfg *config.NetConfig) (net.IP, net.IP, bool) {
+	host, _, err := net.SplitHostPort(ipstr)
 	if err != nil {
 		host = ipstr
 	}
 
-	// We can ignore this error, because ports that are 0 are assumed to be the
-	// port parameter provided in the "port" param of the announce request.
-	parsedPort, _ := strconv.ParseUint(port, 10, 16)
-
 	if ip := net.ParseIP(host); ip != nil {
 		ipTo4 := ip.To4()
 		if ipv4 == nil && ipTo4 != nil {
-			ipv4 = &models.Endpoint{ipTo4, uint16(parsedPort)}
+			ipv4 = ipTo4
 		} else if ipv6 == nil && ipTo4 == nil {
-			ipv6 = &models.Endpoint{ip, uint16(parsedPort)}
+			ipv6 = ip
 		}
 	}