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).

3 files changed, 37 insertions, 0 deletions

diff --git a/usr.bin/ftp/extern.h b/usr.bin/ftp/extern.h
index d935d9e..54ccd79 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 f306406..0643e5d 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 a4c350f..8d38669 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;
+}