From efc3474d1b35baf031f8b40b948388b2d42792b8 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Fri, 8 Sep 2017 12:56:29 +0200
Subject: [PATCH] Add proper destination address when answering an UDP client.

---
 rinetd.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/rinetd.c b/rinetd.c
index e3f2488..5dce084 100644
--- a/rinetd.c
+++ b/rinetd.c
@@ -543,8 +543,17 @@ static void handleWrite(ConnectionInfo *cnx, Socket *socket, Socket *other_socke
 		socket->fd = INVALID_SOCKET;
 		return;
 	}
-	int got = send(socket->fd, other_socket->buffer + socket->sentPos,
-		other_socket->recvPos - socket->sentPos, 0);
+
+	struct sockaddr const *addr = NULL;
+	SOCKLEN_T addrlen = 0;
+	if (socket->proto == protoUdp && socket == &cnx->remote) {
+		addr = (struct sockaddr const*)&cnx->remoteAddress;
+		addrlen = (SOCKLEN_T)sizeof(cnx->remoteAddress);
+	}
+
+	int got = sendto(socket->fd, other_socket->buffer + socket->sentPos,
+		other_socket->recvPos - socket->sentPos, 0,
+		addr, addrlen);
 	if (got < 0) {
 		if (GetLastError() == WSAEWOULDBLOCK) {
 			return;