Not sure if this is the correct fix. ftpfs to a tiny embedded
ftp server which doesn't support PASV (rare these days) provokes
the use of PORT. PORT replies with the IP address of 0.0.0.0
This is due to the contents of /net/tcp/n/local (after announce())
being ::!29274 (missing IP address).

Maybe this is history? Perhaps announce used to give the local address
before connection and now either doesn't or only does after the
connection is successfull; the port is correct though.

My fix is to use myipaddr() to fetch the IP address, which works.

-Steve

Reference: /n/sources/patch/applied/ftpfs-port
Date: Mon Dec 20 18:58:51 CET 2004

--- /sys/src/cmd/ip/ftpfs/proto.c	Mon Dec 20 18:58:51 2004
+++ /sys/src/cmd/ip/ftpfs/proto.c	Mon Dec 20 18:58:51 2004
@@ -1167,8 +1167,16 @@
 	if(ptr)
 		*ptr = 0;
 	ptr = strchr(buf, '!')+1;
-	parseip(ipaddr, buf);
 	port = atoi(ptr);
+
+	memset(ipaddr, 0, IPaddrlen);
+	if (*net){
+		strcpy(buf, net);
+		ptr = strchr(buf +1, '/');
+		if (ptr)
+			*ptr = 0;
+		myipaddr(ipaddr, buf);
+	}
 
 	/* tell remote side */
 	sprint(buf, "PORT %d,%d,%d,%d,%d,%d", ipaddr[IPv4off+0], ipaddr[IPv4off+1],