If we receive a large UDP packet, don't return an error to receive.go,
which then terminates the receive loop. Instead, simply retry.
Considering Winsock's general finickiness, we might consider other
places where an attacker on the wire can generate error conditions like
this.
Reported-by: Sascha Dierberg <sascha.dierberg@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
By not comparing these with the modulo, the ring became nearly never
full, resulting in completion queue buffers filling up prematurely.
Reported-by: Joshua Sjoding <joshua.sjoding@scjalliance.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Instead of hard-coding exactly two sources from which
to receive packets (an IPv4 source and an IPv6 source),
allow the conn.Bind to specify a set of sources.
Beneficial consequences:
* If there's no IPv6 support on a system,
conn.Bind.Open can choose not to return a receive function for it,
which is simpler than tracking that state in the bind.
This simplification removes existing data races from both
conn.StdNetBind and bindtest.ChannelBind.
* If there are more than two sources on a system,
the conn.Bind no longer needs to add a separate muxing layer.
Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
This makes it clearer that they are fresh on each attempt,
and avoids the bookkeeping required to clearing them on failure.
Also, remove an unnecessary err != nil.
Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
Until we depend on Go 1.16 (which isn't released yet), alias our own
variable to the private member of the net package. This will allow an
easy find replace to make this go away when we eventually switch to
1.16.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Some users report seeing lines like:
> Routine: receive incoming IPv4 - stopped
Popping up unexpectedly. Let's sleep and try again before failing, and
also log the error, and perhaps we'll eventually understand this
situation better in future versions.
Because we have to distinguish between the socket being closed
explicitly and whatever error this is, we bump the module to require Go
1.16.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
If Close is called after ReceiveIPvX, then ReceiveIPvX will block on an
invalid or potentially reused fd.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The sticky socket code stays in the device package for now,
as it reaches deeply into the peer list.
This is the first step in an effort to split some code out of
the very busy device package.
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
