Made getsockopt() and setsockopt() virtual so we can handle them in the
various Socket subclasses. The subclasses map kinda nicely to "levels".
This will allow us to implement things like "traceroute", although..
I spent some time trying to do that, but then hit a wall when it turned
out that the user-mode networking in QEMU doesn't preserve TTL in the
ICMP packets passing through.
This approach is a bit naiive - whenever we send a packet out, we
check to see if there are any other packets we should try to send.
This works well enough for a busy connection but not very well for a
quiet one. Ideally we would check for not-acked packets on some kind
of timer, and use the length of this not-acked list as feedback to
throttle the writes coming from userspace.
This replaces the previous placeholder routing layer with a real one!
It's still very primitive, doesn't deal with things like timeouts very
well, and will probably need several more iterations to support more
normal networking things.
I haven't confirmed that this works with anything other than the QEMU
user networking layer, but I suspect that's what nearly everybody is
using at this point, so that's the important target to keep working.
This is more logical and allows us to solve the problem of
non-blocking TCP sockets getting stuck in SocketRole::None.
The only complication is that a single LocalSocket may be shared
between two file descriptions (on the connect and accept sides),
and should have two different roles depending from which side
you look at it. To deal with it, Socket::role() is made a
virtual method that accepts a file description, and LocalSocket
internally tracks which FileDescription is the which one and
returns a correct role.
This is comprised of five small changes:
* Keep a counter for tx/rx packets/bytes per TCP socket
* Keep a counter for tx/rx packets/bytes per network adapter
* Expose that data in /proc/net_tcp and /proc/netadapters
* Convert /proc/netadapters to JSON
* Fix up ifconfig to read the JSON from netadapters
This has several significant changes to the networking stack.
* Significant refactoring of the TCP state machine. Right now it's
probably more fragile than it used to be, but handles quite a lot
more of the handshake process.
* `TCPSocket` holds a `NetworkAdapter*`, assigned during `connect()` or
`bind()`, whichever comes first.
* `listen()` is now virtual in `Socket` and intended to be implemented
in its child classes
* `listen()` no longer works without `bind()` - this is a bit of a
regression, but listening sockets didn't work at all before, so it's
not possible to observe the regression.
* A file is exposed at `/proc/net_tcp`, which is a JSON document listing
the current TCP sockets with a bit of metadata.
* There's an `ETHERNET_VERY_DEBUG` flag for dumping packet's content out
to `kprintf`. It is, indeed, _very debug_.
There's no need for send_ipv4() to take a ByteBuffer&&, the data is
immediately cooked into a packet and transmitted. Instead, just pass
it the address+length of whatever buffer we've been using locally.
The more we can reduce the pressure on kmalloc the better. :^)
And use this to return EINTR in various places; some of which we were
not handling properly before.
This might expose a few bugs in userspace, but should be more compatible
with other POSIX systems, and is certainly a little cleaner.
After reading a bunch of POSIX specs, I've learned that a file descriptor
is the number that refers to a file description, not the description itself.
So this patch renames FileDescriptor to FileDescription, and Process now has
FileDescription* file_description(int fd).
It was way too ambiguous who's the source and who's the destination, and it
didn't really follow a logical pattern. "Local port" vs "Peer port" is super
obvious, so let's call it that.
Make the Socket functions take a FileDescriptor& rather than a socket role
throughout the code. Also change threads to block on a FileDescriptor,
rather than either an fd index or a Socket.
If connect() is called on a non-blocking socket, it will "fail" immediately
with -EINPROGRESS. After that, you select() on the socket and wait for it to
become writable.
