Don't try to take it on board in your carry on lugage. It may be taken up and given back to you at the end of the cruise.
My husband and I pack our liquor in the plastic travel bottles in our checked luggage. This seems to work and we have never had a problem. You can buy Gin & Vodka,
probably others, but this is what we take. Along with some vermouth and a squeeze
bottle of lime juice.
You can then order the "mixers" from room service @ about $1.50 a can. We are a long
way from cheap, but our last cruise almost cost us as much to get off the ship and it
did to get on. At $5.75 and up a drink, it can get to be quite expensive.
And, it seems to take forever to get a drink thru room service during "happy hour".