Naturally, it's a struct pubkey. However, those are large, and take
time to marshal, so gossipd treats them as node_id which is a simple
array. It adds explicit checks at the right points to make sure
they're valid pubkeys.
However, the next commit adds TLV test vectors, which assumes we treat
node_id as a point (thus catch invalid values when parsing). The best
solution is to restrain our types here to exactly those we've
optimized for.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
4b5cd5ff84