ftpgetput: add EPSV support (PASV-like thing for IPv6)

Based on a patch by Kev Kitchens.

function                                             old     new   delta
xconnect_ftpdata                                     149     223     +74

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files 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);