[PATCH]Extending user at host syntax

[Torsten Foertsch]

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Hash: SHA1

Hi,

the following patch extends the user at host syntax on the ssh command line to 
allow an additional HostKeyAlias and Port to be given as a single argument, eg:

  ssh user at localhost%8022,www.tdl.com

is equivalent to

  ssh -o 'HostKeyAlias www.tdl.com' -p 8022 user at localhost

The patch is particularly useful when ssh is called from other programs or 
scripts and the ssh connection is to be established on top of a tunnel. 
Consider for example a CVS repository that is connected using ssh through 
a tunnel. The CVS/Root file contains the path to the CVS root as:

  user at www.tld.com:/path/to/cvs

There is no way to specify a port number or a HostKeyAlias. With the patch 
the CVS/Root can contain:

  user at localhost%8022,www.tld.com:/path/to/cvs

and the connection is made through the tunnel.

I know I can achieve a similar result using .ssh/config:

Host host_nickname
Hostname localhost
Port 8022
HostKeyAlias www.tld.com

and specify the CVS root as user at host_nickname:/path/to/cvs

However, I think my patch is rather a feature than a bug. Are there any 
chances to get it included in openssh?

Torsten

diff -Naur openssh-3.9p1/ssh.c openssh-3.9p1.new/ssh.c
- --- openssh-3.9p1/ssh.c	2004-08-15 09:23:34.000000000 +0200
+++ openssh-3.9p1.new/ssh.c	2004-09-08 16:12:58.000000000 +0200
@@ -157,7 +157,8 @@
 "usage: ssh [-1246AaCfghkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 "           [-D port] [-e escape_char] [-F configfile] [-i identity_file]\n"
 "           [-L port:host:hostport] [-l login_name] [-m mac_spec] [-o option]\n"
- -"           [-p port] [-R port:host:hostport] [-S ctl] [user@]hostname [command]\n"
+"           [-p port] [-R port:host:hostport] [-S ctl]\n"
+"           [user@]hostname[%%port][,host_key_alias] [command]\n"
 	);
 	exit(1);
 }
@@ -176,7 +177,7 @@
 	int i, opt, exit_status;
 	u_short fwd_port, fwd_host_port;
 	char sfwd_port[6], sfwd_host_port[6];
- -	char *p, *cp, *line, buf[256];
+	char *p, *cp, *line, buf[256], *host_key_aliasp;
 	struct stat st;
 	struct passwd *pw;
 	int dummy;
@@ -474,6 +475,28 @@
 			host = ++cp;
 		} else
 			host = *av;
+
+		host_key_aliasp = 0;
+		if (strrchr(host, '%')) {
+			cp = strrchr(host, '%');
+			*cp++ = '\0';
+			if (strrchr(cp, ',')) {
+				host_key_aliasp = strrchr(cp, ',');
+				*host_key_aliasp++ = '\0';
+			}
+			options.port = a2port(cp);
+			if (options.port == 0) {
+				fprintf(stderr, "Bad port '%s'\n", cp);
+				exit(1);
+			}
+		} else if (strrchr(host, ',')) {
+			host_key_aliasp = strrchr(host, ',');
+			*host_key_aliasp++ = '\0';
+		}
+
+		if (host_key_aliasp)
+			options.host_key_alias = xstrdup(host_key_aliasp);
+
 		if (ac > 1) {
 			optind = optreset = 1;
 			goto again;
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