[tor-commits] [snowflake/master] In server, treat a client IP address of 0.0.0.0 as missing.

[dcf at torproject.org]

commit c124e8c643f2de5730af9079d326b9cabc3b264a
Author: David Fifield <david at bamsoftware.com>
Date:   Wed Feb 19 10:44:35 2020 -0700

    In server, treat a client IP address of 0.0.0.0 as missing.
    
    Some proxies currently send ?client_ip=0.0.0.0 because of an error in
    how they attempt to grep the address from the client's SDP. That's
    inflating our "%d/%d connections had client_ip" logs. Instead, treat
    these cases as if the IP address were absent.
    https://bugs.torproject.org/33157
    https://bugs.torproject.org/33385
---
 server/server.go      | 5 +++++
 server/server_test.go | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/server/server.go b/server/server.go
index c484a19..6e9fb19 100644
--- a/server/server.go
+++ b/server/server.go
@@ -88,6 +88,11 @@ func clientAddr(clientIPParam string) string {
 	if clientIP == nil {
 		return ""
 	}
+	// Check if client addr is 0.0.0.0 or [::]. Some proxies erroneously
+	// report an address of 0.0.0.0: https://bugs.torproject.org/33157.
+	if clientIP.IsUnspecified() {
+		return ""
+	}
 	// Add a dummy port number. USERADDR requires a port number.
 	return (&net.TCPAddr{IP: clientIP, Port: 1, Zone: ""}).String()
 }
diff --git a/server/server_test.go b/server/server_test.go
index d4ada6e..ba00d16 100644
--- a/server/server_test.go
+++ b/server/server_test.go
@@ -46,6 +46,8 @@ func TestClientAddr(t *testing.T) {
 			"abc",
 			"1.2.3.4.5",
 			"[12::34]",
+			"0.0.0.0",
+			"[::]",
 		} {
 			useraddr := clientAddr(input)
 			if useraddr != "" {