openssl/include/internal/quic_srtm.h
Dimitri Papadopoulos 164a541b93 Fix new typos found by codespell
Reviewed-by: Paul Yang <kaishen.yy@antfin.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23133)
2023-12-29 10:12:05 +01:00

110 lines
4.3 KiB
C

/*
* Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OSSL_INTERNAL_QUIC_SRTM_H
# define OSSL_INTERNAL_QUIC_SRTM_H
# pragma once
# include "internal/e_os.h"
# include "internal/time.h"
# include "internal/quic_types.h"
# include "internal/quic_wire.h"
# include "internal/quic_predef.h"
# ifndef OPENSSL_NO_QUIC
/*
* QUIC Stateless Reset Token Manager
* ==================================
*
* The stateless reset token manager is responsible for mapping stateless reset
* tokens to connections. It is used to identify stateless reset tokens in
* incoming packets. In this regard it can be considered an alternate "routing"
* mechanism for incoming packets, and is somewhat analogous with the LCIDM,
* except that it uses SRTs to route rather than DCIDs.
*
* The SRTM specifically stores a bidirectional mapping of the form
*
* (opaque pointer, sequence number) [1] <-> [0..n] SRT
*
* The (opaque pointer, sequence number) tuple is used to refer to an entry (for
* example for the purposes of removing it later when it is no longer needed).
* Likewise, an entry can be looked up using SRT to get the opaque pointer and
* sequence number.
*
* It is important to note that the same SRT may exist multiple times and map to
* multiple (opaque pointer, sequence number) tuples, for example, if we
* initiate multiple connections to the same peer using the same local QUIC_PORT
* and the peer decides to behave bizarrely and issue the same SRT for both
* connections. It should not do this, but we have to be resilient against
* byzantine peer behaviour. Thus we are capable of storing multiple identical
* SRTs for different (opaque pointer, sequence number) keys.
*
* The SRTM supports arbitrary insertion, arbitrary deletion of specific keys
* identified by a (opaque pointer, sequence number) key, and mass deletion of
* all entries under a specific opaque pointer. It supports lookup by SRT to
* identify zero or more corresponding (opaque pointer, sequence number) tuples.
*
* The opaque pointer may be used for any purpose but is intended to represent a
* connection identity and must therefore be consistent (usefully comparable).
*/
/* Creates a new empty SRTM instance. */
QUIC_SRTM *ossl_quic_srtm_new(OSSL_LIB_CTX *libctx, const char *propq);
/* Frees a SRTM instance. No-op if srtm is NULL. */
void ossl_quic_srtm_free(QUIC_SRTM *srtm);
/*
* Add a (opaque, seq_num) -> SRT entry to the SRTM. This operation fails if a
* SRT entry already exists with the same (opaque, seq_num) tuple. The token is
* copied. Returns 1 on success or 0 on failure.
*/
int ossl_quic_srtm_add(QUIC_SRTM *srtm, void *opaque, uint64_t seq_num,
const QUIC_STATELESS_RESET_TOKEN *token);
/*
* Removes an entry by identifying it via its (opaque, seq_num) tuple.
* Returns 1 if the entry was found and removed, and 0 if it was not found.
*/
int ossl_quic_srtm_remove(QUIC_SRTM *srtm, void *opaque, uint64_t seq_num);
/*
* Removes all entries (opaque, *) with the given opaque pointer.
*
* Returns 1 on success and 0 on failure. If no entries with the given opaque
* pointer were found, this is considered a success condition.
*/
int ossl_quic_srtm_cull(QUIC_SRTM *strm, void *opaque);
/*
* Looks up a SRT to find the corresponding opaque pointer and sequence number.
* An output field pointer can be set to NULL if it is not required.
*
* This function is designed to avoid exposing timing channels on token values
* or the contents of the SRT mapping.
*
* If there are several identical SRTs, idx can be used to get the nth entry.
* Call this function with idx set to 0 first, and keep calling it after
* incrementing idx until it returns 0.
*
* Returns 1 if an entry was found and 0 otherwise.
*/
int ossl_quic_srtm_lookup(QUIC_SRTM *srtm,
const QUIC_STATELESS_RESET_TOKEN *token,
size_t idx,
void **opaque, uint64_t *seq_num);
/* Verify internal invariants and assert if they are not met. */
void ossl_quic_srtm_check(const QUIC_SRTM *srtm);
# endif
#endif