initial code added to support EPSV (IPv6-style PASV)

lib/ftp.c

@@ -1258,6 +1258,23 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
   char *buf = data->state.buffer; /* this is our buffer */
   int ftpcode; /* receive FTP response codes in this */
   CURLcode result;
+  Curl_addrinfo *addr=NULL;
+  Curl_ipconnect *conninfo;
+
+  /*
+    Here's the excecutive summary on what to do:
+
+    PASV is RFC959, expect:
+    227 Entering Passive Mode (a1,a2,a3,a4,p1,p2)
+
+    LPSV is RFC1639, expect:
+    228 Entering Long Passive Mode (4,4,a1,a2,a3,a4,2,p1,p2)
+    (Is this actually supported *anywhere*?)
+
+    EPSV is RFC2428, expect:
+    229 Entering Extended Passive Mode (|||port|)
+
+  */
 
 #if 0
   /* no support for IPv6 passive mode yet */
@@ -1268,6 +1285,13 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
   int results[] = { 227, 0 };
 #endif
   int modeoff;
+  unsigned short connectport; /* the local port connect() should use! */
+  unsigned short newport; /* remote port, not necessary the local one */
+  char *hostdataptr=NULL;
+  
+  /* newhost must be able to hold a full IP-style address in ASCII, which
+     in the IPv6 case means 5*8-1 = 39 letters */
+  char newhost[48];
   
   for (modeoff = 0; mode[modeoff]; modeoff++) {
     FTPSENDF(conn, mode[modeoff], "");
@@ -1283,16 +1307,9 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
     failf(data, "Odd return code after PASV");
     return CURLE_FTP_WEIRD_PASV_REPLY;
   }
-  else if (strcmp(mode[modeoff], "PASV") == 0) {
+  else if (227 == results[modeoff]) {
     int ip[4];
     int port[2];
-    unsigned short newport; /* remote port, not necessary the local one */
-    unsigned short connectport; /* the local port connect() should use! */
-    char newhost[32];
-    
-    Curl_addrinfo *addr;
-    char *hostdataptr=NULL;
-    Curl_ipconnect *conninfo;
     char *str=buf;
 
     /*
@@ -1321,6 +1338,42 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
 
     sprintf(newhost, "%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3]);
     newport = (port[0]<<8) + port[1];
+
+    /* we should compare to see if this is the same IP like the one
+       we're already connected to, as then we can skip the name function
+       call below, in similar style that we do for the EPSV reply */
+  }
+#if 1
+  else if (strcmp(mode[modeoff], "EPSV") == 0) {
+    char *ptr = strchr(buf, '(');
+    if(ptr) {
+      unsigned int num;
+      char separator[4];
+      ptr++;
+      if(5  == sscanf(ptr, "%c%c%c%u%c",
+                      &separator[0],
+                      &separator[1],
+                      &separator[2],
+                      &num,
+                      &separator[3])) {
+        /* the four separators should be identical */
+        newport = num;
+
+        /* we should use the same host we already are connected to */
+        addr = conn->hostaddr;
+      }                      
+      else
+        ptr=NULL;
+    }
+    if(!ptr) {
+      failf(data, "Weirdly formatted EPSV reply");
+      return CURLE_FTP_WEIRD_PASV_REPLY;
+    }
+  }
+#endif
+  else
+    return CURLE_FTP_CANT_RECONNECT;
+
   if(data->change.proxy) {
     /*
      * This is a tunnel through a http proxy and we need to connect to the
@@ -1331,7 +1384,7 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
     connectport =
       (unsigned short)conn->port; /* we connect to the proxy's port */
   }
-    else {
+  else if(!addr) {
     /* normal, direct, ftp connection */
     addr = Curl_getaddrinfo(data, newhost, newport, &hostdataptr);
     if(!addr) {
@@ -1365,9 +1418,6 @@ CURLcode ftp_use_pasv(struct connectdata *conn)
     if(CURLE_OK != result)
       return result;
   }
-  }
-  else
-    return CURLE_FTP_CANT_RECONNECT;
 
   return CURLE_OK;
 }