Re: Nsock unconnected sockets

[David Fifield <david () bamsoftware com>]

On Sun, Oct 03, 2010 at 10:03:41PM -0500, Kris Katterjohn wrote:
> On 10/03/2010 08:03 PM, David Fifield wrote:
> > Some questions:
> >
> > 1. What do you think of the names nsock_setup_udp and sock:setup? The
> >    way to understand how it works is to know that "setup" is what you
> >    use instead of "connect" when you want an unconnected socket. Is
> >    there a name other than "setup" that conveys that better?
>
> I don't particularly like "setup" because with a name like that it sounds like
> you should call it for every socket, not just for unconnected ones.
>
> I can't think of a better separate function name right now either, but an API
> change of something like
>
> nmap.new_socket(<proto>, <family>)
>
> with optional arguments is what I first thought of as an alternative because
> your "setup" is akin to an actual socket() call anyway.

Yes, that's a good interface. It is more magical though. Normally after
calling new_socket you have only an Nsock iod, not a real socket that
you can start sending on. The socket doesn't appear until you connect.
I'm afraid that adding parameters to new_socket will make people think
that they should do

s = nmap.new_socket("tcp")
s:connect(host, port, "tcp")

when that would be wrong and would actually have created a socket twice.

> However, I'm not sure if setup() can be called multiple times or not, or if
> new sockets should be created (in fact, I'm not sure about connect either).

I think that connect and setup both leak a socket if you call them twice
without closing. But that can be fixed.

> > 2. What do you think of the NSE API,
> >    s:setup("udp")
> >    s:setup("udp", "ipv4")
> >    s:setup("udp", "ipv6")
> >    We have a precedent for using "udp" as a protocol identifier. I think
> >    that the strings "ipv4" and "ipv6" are better than constants like
> >    nmap.AF_INET and nmap.AF_INET6. Another possibility would be "in" and
> >    "in6" but I think the ones I've chosen are easier to remember.
>
> Using "udp" sounds good, but my resolve() and address_family() functions use
> "inet" and "inet6", which I like best (I considered "ipv4" and "ipv6" for
> them, too).  I don't like the nmap.AF_INET constants either, but using "inet"
> in there just seems better to me.

Thanks, that's just what I was looking for. I didn't know that there was
already a convention.

David Fifield
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