[git commit] ftpgetput: add EPSV support (PASV-like thing for IPv6)

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=05b84d4e92b79fa47259907a78d8375bb5490135
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

Based on a patch by Kev Kitchens.

function                                             old     new   delta
xconnect_ftpdata                                     149     223     +74

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 networking/ftpgetput.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/networking/ftpgetput.c b/networking/ftpgetput.c
index 3f98e07f3..697955e82 100644
--- a/networking/ftpgetput.c
+++ b/networking/ftpgetput.c
@@ -156,7 +156,7 @@ static int xconnect_ftpdata(void)
 	unsigned port_num;
 
 /*
-TODO: PASV command will not work for IPv6. RFC2428 describes
+PASV command will not work for IPv6. RFC2428 describes
 IPv6-capable "extended PASV" - EPSV.
 
 "EPSV [protocol]" asks server to bind to and listen on a data port
@@ -171,15 +171,16 @@ but we don't need that.
 NB: PASV may still work for some servers even over IPv6.
 For example, vsftp happily answers
 "227 Entering Passive Mode (0,0,0,0,n,n)" and proceeds as usual.
-
-TODO2: need to stop ignoring IP address in PASV response.
 */
-	//if (ftpcmd("EPSV", NULL) != 229) {
+	if (!ENABLE_FEATURE_IPV6
+	 || ftpcmd("EPSV", NULL) != 229
+	) {
+/* maybe also go straight to PAST if lsa->u.sa.sa_family == AF_INET? */
 		if (ftpcmd("PASV", NULL) != 227) {
 			ftp_die("PASV");
 		}
 
-		/* Response is "NNN garbageN1,N2,N3,N4,P1,P2[)garbage]
+		/* Response is "NNN garbageN1,N2,N3,N4,P1,P2[)garbage]"
 		 * Server's IP is N1.N2.N3.N4 (we ignore it)
 		 * Server's port for data connection is P1*256+P2 */
 		buf_ptr = strrchr(buf, ')');
@@ -192,7 +193,16 @@ TODO2: need to stop ignoring IP address in PASV response.
 		buf_ptr = strrchr(buf, ',');
 		*buf_ptr = '\0';
 		port_num += xatoul_range(buf_ptr + 1, 0, 255) * 256;
-	//}
+	} else {
+		/* Response is "NNN garbage(|||P1|)"
+		 * Server's port for data connection is P1 */
+		buf_ptr = strrchr(buf, '|');
+		if (buf_ptr) *buf_ptr = '\0';
+
+		buf_ptr = strrchr(buf, '|');
+		*buf_ptr = '\0';
+		port_num = xatoul_range(buf_ptr + 1, 0, 65535);
+	}
 
 	set_nport(&lsa->u.sa, htons(port_num));
 	return xconnect_stream(lsa);