From bc67101b31cca86a0c4428766426a0562e6b82e0 Mon Sep 17 00:00:00 2001
From: Hajimu UMEMOTO <ume@FreeBSD.org>
Date: Wed, 14 Jun 2000 15:26:58 +0000
Subject: [PATCH] Make sure to use native IPv4 addrerss even if getaddrinfo()
 returns IPv4 mapped IPv6 address.  FTP is nervous about address family.
 Submitted by itojun and slightly modified to fit our ftp(1).

---
 usr.bin/ftp/extern.h |  1 +
 usr.bin/ftp/fetch.c  |  1 +
 usr.bin/ftp/ftp.c    | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/usr.bin/ftp/extern.h b/usr.bin/ftp/extern.h
index d935d9e86fa4..54ccd79e812d 100644
--- a/usr.bin/ftp/extern.h
+++ b/usr.bin/ftp/extern.h
@@ -41,6 +41,7 @@ void    abortpt __P((int));
 void    abortrecv __P((int));
 void    abortsend __P((int));
 void	account __P((int, char **));
+void	ai_unmapped __P((struct addrinfo *));
 void	alarmtimer __P((int));
 int	another __P((int *, char ***, const char *));
 int	auto_fetch __P((int, char **));
diff --git a/usr.bin/ftp/fetch.c b/usr.bin/ftp/fetch.c
index f306406182d2..0643e5d78423 100644
--- a/usr.bin/ftp/fetch.c
+++ b/usr.bin/ftp/fetch.c
@@ -217,6 +217,7 @@ url_get(origline, proxyenv)
 
 	while (1)
       {
+	ai_unmapped(res);
 	s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 	if (s == -1) {
 		res = res->ai_next;
diff --git a/usr.bin/ftp/ftp.c b/usr.bin/ftp/ftp.c
index a4c350fac774..8d3866950630 100644
--- a/usr.bin/ftp/ftp.c
+++ b/usr.bin/ftp/ftp.c
@@ -139,6 +139,13 @@ hookup(host0, port)
 			       sizeof(hostnamebuf));
 	hostname = hostnamebuf;
 	while (1) {
+		/*
+		 * make sure that ai_addr is NOT an IPv4 mapped address.
+		 * IPv4 mapped address complicates too many things in FTP
+		 * protocol handling, as FTP protocol is defined differently
+		 * between IPv4 and IPv6.
+		 */
+		ai_unmapped(res);
 		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 		if (s < 0) {
 			res = res->ai_next;
@@ -1928,3 +1935,31 @@ abort_remote(din)
 	}
 	(void)getreply(0);
 }
+
+void
+ai_unmapped(ai)
+	struct addrinfo *ai;
+{
+	struct sockaddr_in6 *sin6;
+	struct sockaddr_in sin;
+
+	if (ai->ai_family != AF_INET6)
+		return;
+	if (ai->ai_addrlen != sizeof(struct sockaddr_in6) ||
+	    sizeof(sin) > ai->ai_addrlen)
+		return;
+	sin6 = (struct sockaddr_in6 *)ai->ai_addr;
+	if (!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
+		return;
+
+	memset(&sin, 0, sizeof(sin));
+	sin.sin_family = AF_INET;
+	sin.sin_len = sizeof(struct sockaddr_in);
+	memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
+	    sizeof(sin.sin_addr));
+	sin.sin_port = sin6->sin6_port;
+
+	ai->ai_family = AF_INET;
+	memcpy(ai->ai_addr, &sin, sin.sin_len);
+	ai->ai_addrlen = sin.sin_len;
+}