| Age | Commit message (Collapse) | Author |
|---|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
If it's time to rekey, and the responder sends a message, the initator
will begin the rekeying when sending his response message. In the worst
case, this response message will actually just be the keepalive. This
generally works well, with the one edge case of the message arriving
less than 10 seconds before key expiration, in which the keepalive is
not sufficient. In this case, we simply rehandshake immediately.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
With the prior behavior, when sending a packet, we checked to see if it
was about time to start a new handshake, and if we were past a certain
time, we started it. For the responder, we made that time a bit further
in the future than for the initiator, to prevent the thundering herd
problem of them both starting at the same time. However, this was
flawed.
If both parties stopped communicating after 2.2 minutes, and then one
party decided to initiate a TCP connection before the 3 minute mark, the
currently open session would be used. However, because it was after the
2.2 minute mark, both peers would try to initiate a handshake upon
sending their first packet. The errant flow was as follows:
1. Peer A sends SYN.
2. Peer A sees that his key is getting old and initiates new handshake.
3. Peer B receives SYN and sends ACK.
4. Peer B sees that his key is getting old and initiates new handshake.
Since these events happened after the 2.2 minute mark, there's no delay
between handshake initiations, and problems begin. The new behavior is
changed to:
1. Peer A sends SYN.
2. Peer A sees that his key is getting old and initiates new handshake.
3. Peer B receives SYN and sends ACK.
4. Peer B sees that his key is getting old and schedules a delayed
handshake for 12.5 seconds in the future.
5. Peer B receives handshake initiation and cancels scheduled handshake.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Since it's extremely unlikely for jiffies to be exactly identical
everywhere, applying quarter second power of two slack not only improves
power efficiency but also ensures that retries have a bit of jitter.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
No longer do we specify slack ourselves. Instead we need to add it
directly in the main scheduling.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
For timers in the hotpath, we don't want them to be rescheduled so
aggressively, and since they don't need to be that precise, we can set a
decent amount of slack.
With the persistent keepalive timer, we have something of a special
case. Since the timeout isn't fixed like the others, we don't want to
make it more often than the kernel ordinarily would. So, instead, we
make it a minimum.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
