83f9040339
This extends the packet adaptor protocol to send three commands:
type command =
| Packet of []byte
| Timeout of time.Duration
| TimeoutAck
When the shim processes a Timeout in BIO_read, it sends TimeoutAck, fails the
BIO_read, returns out of the SSL stack, advances the clock, calls
DTLSv1_handle_timeout, and continues.
If the Go side sends Timeout right between sending handshake flight N and
reading flight N+1, the shim won't read the Timeout until it has sent flight
N+1 (it only processes packet commands in BIO_read), so the TimeoutAck comes
after N+1. Go then drops all packets before the TimeoutAck, thus dropping one
transmit of flight N+1 without having to actually process the packets to
determine the end of the flight. The shim then sees the updated clock, calls
DTLSv1_handle_timeout, and re-sends flight N+1 for Go to process for real.
When dropping packets, Go checks the epoch and increments sequence numbers so
that we can continue to be strict here. This requires tracking the initial
sequence number of the next epoch.
The final Finished message takes an additional special-case to test. DTLS
triggers retransmits on either a timeout or seeing a stale flight. OpenSSL only
implements the former which should be sufficient (and is necessary) EXCEPT for
the final Finished message. If the peer's final Finished message is lost, it
won't be waiting for a message from us, so it won't time out anything. That
retransmit must be triggered on stale message, so we retransmit the Finished
message in Go.
Change-Id: I3ffbdb1de525beb2ee831b304670a3387877634c
Reviewed-on: https://boringssl-review.googlesource.com/3212
Reviewed-by: Adam Langley <agl@google.com>
35 lines
1.5 KiB
C
35 lines
1.5 KiB
C
/* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#ifndef HEADER_PACKETED_BIO
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#define HEADER_PACKETED_BIO
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#include <openssl/bio.h>
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#include <openssl/ssl.h>
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// packeted_bio_create creates a filter BIO which implements a reliable in-order
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// blocking datagram socket. The resulting BIO, on |BIO_read|, may simulate a
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// timeout which sets |*out_timeout| to the timeout and fails the read.
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// |*out_timeout| must be zero on entry to |BIO_read|; it is an error to not
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// apply the timeout before the next |BIO_read|.
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//
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// Note: The read timeout simulation is intended to be used with the async BIO
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// wrapper. It doesn't simulate BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, used in DTLS's
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// blocking mode.
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BIO *packeted_bio_create(OPENSSL_timeval *out_timeout);
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#endif // HEADER_PACKETED_BIO
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