This utility can be used to manually create LSPs from the command line.
It is also a great example of how to use the Netlink/IOCTLS calls.

Command line usage:

usage: mplsadm [ADBUdhvT:f:L:I:O:i:o:]

-A add modifier
-B bind modifier
-D delete modifier
-U unbind modifier
-d toggle debug
-h this message
-v verbose info
-T <tunnel name>:<dest addr>
-f <prefix/len>
-L <interface name>:<label space> set the label space for an interface 
   (-1 disables)
-I <gen|atm|fr>:<label>:<label space> create|delete an incoming label
-O <gen|atm|fr>:<label>:<out interface>[:<next type>:<next hop>]
-i <opcode:opcode_data>+
-o <opcode:opcode_data>+

Combinations of command line options:

-A/-D can be used with -T -I -O
-B/-U can be used with -T and -O, -I and -O, -O and -f

-i/-o MUST be used with -I/-O respectivly

Example use of mplsadm:

Create an out going label entry for FEC 128.140.1.0/24 that points out eth0 to
the next hop nero.  Send all packets that match this FEC with the generic
label of 16

Establish an out going label entry for 128.104.1.0/24
-----------------------------------------------------

mplsadm -A -O gen:16:eth0:ipv4:128.104.17.130
         |  | |   |  |    |    |
       add  | |   |  |    |    |
            | |   |  |    |    |
            | |   |  |    |    |
            | |   |  |    |    IP addr of next hop
            | |   |  |    |
            | |   |  |    following info is ipv4 for the L2 nexthop
            | |   |  |
            | |   |  out going interface
            | |   |
            | |   label
            | |
            | generic label
            |
            |
            outgoing label

(if you switch the -A to -D you delete the entry)

Bind FEC 128.104.1.0/24 to the outgoing label
---------------------------------------------
mplsadm -B -O gen:16:eth0 -f 128.104.1.0/24
         |  |              |
         |  |              FEC to bind to
         |  |            
         |  Key for the outgoing label entry
         |
         bind modifier

Interface eth0 uses label space 0
---------------------------------
mplsadm -L eth0:0
         | |    |
         | |    label space
         | |
         | interface name
         |
         modify interface label space

(if you change the label space to -1, you disable MPLS processing on the
 interface)

Establish label 34 in label space 0
-----------------------------------

mplsadm -A -I gen:34:0
         |  | |   |  |
         |  | |   |  label space
       add  | |   |
            | |   label
            | |
            | generic label
            |
            incoming label

(if you change the -A to -D you will delete the entry)

Establish a label switch path
-----------------------------
mplsadm -A -B -I gen:34:0 -O gen:16:eth0

Delete a label switch path 
--------------------------
mplsadm -D -B -I gen:34:0 -O gen:16:eth0: