2 * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #ifndef OSSL_INTERNAL_QUIC_SRTM_H
11 # define OSSL_INTERNAL_QUIC_SRTM_H
14 # include "internal/e_os.h"
15 # include "internal/time.h"
16 # include "internal/quic_types.h"
17 # include "internal/quic_wire.h"
18 # include "internal/quic_predef.h"
20 # ifndef OPENSSL_NO_QUIC
23 * QUIC Stateless Reset Token Manager
24 * ==================================
26 * The stateless reset token manager is responsible for mapping stateless reset
27 * tokens to connections. It is used to identify stateless reset tokens in
28 * incoming packets. In this regard it can be considered an alternate "routing"
29 * mechanism for incoming packets, and is somewhat analagous with the LCIDM,
30 * except that it uses SRTs to route rather than DCIDs.
32 * The SRTM specifically stores a bidirectional mapping of the form
34 * (opaque pointer, sequence number) [1] <-> [0..n] SRT
36 * The (opaque pointer, sequence number) tuple is used to refer to an entry (for
37 * example for the purposes of removing it later when it is no longer needed).
38 * Likewise, an entry can be looked up using SRT to get the opaque pointer and
41 * It is important to note that the same SRT may exist multiple times and map to
42 * multiple (opaque pointer, sequence number) tuples, for example, if we
43 * initiate multiple connections to the same peer using the same local QUIC_PORT
44 * and the peer decides to behave bizarrely and issue the same SRT for both
45 * connections. It should not do this, but we have to be resilient against
46 * byzantine peer behaviour. Thus we are capable of storing multiple identical
47 * SRTs for different (opaque pointer, sequence number) keys.
49 * The SRTM supports arbitrary insertion, arbitrary deletion of specific keys
50 * identified by a (opaque pointer, sequence number) key, and mass deletion of
51 * all entries under a specific opaque pointer. It supports lookup by SRT to
52 * identify zero or more corresponding (opaque pointer, sequence number) tuples.
54 * The opaque pointer may be used for any purpose but is intended to represent a
55 * connection identity and must therefore be consistent (usefully comparable).
58 /* Creates a new empty SRTM instance. */
59 QUIC_SRTM *ossl_quic_srtm_new(OSSL_LIB_CTX *libctx, const char *propq);
61 /* Frees a SRTM instance. No-op if srtm is NULL. */
62 void ossl_quic_srtm_free(QUIC_SRTM *srtm);
65 * Add a (opaque, seq_num) -> SRT entry to the SRTM. This operation fails if a
66 * SRT entry already exists with the same (opaque, seq_num) tuple. The token is
67 * copied. Returns 1 on success or 0 on failure.
69 int ossl_quic_srtm_add(QUIC_SRTM *srtm, void *opaque, uint64_t seq_num,
70 const QUIC_STATELESS_RESET_TOKEN *token);
73 * Removes an entry by identifying it via its (opaque, seq_num) tuple.
74 * Returns 1 if the entry was found and removed, and 0 if it was not found.
76 int ossl_quic_srtm_remove(QUIC_SRTM *srtm, void *opaque, uint64_t seq_num);
79 * Removes all entries (opaque, *) with the given opaque pointer.
81 * Returns 1 on success and 0 on failure. If no entries with the given opaque
82 * pointer were found, this is considered a success condition.
84 int ossl_quic_srtm_cull(QUIC_SRTM *strm, void *opaque);
87 * Looks up a SRT to find the corresponding opaque pointer and sequence number.
88 * An output field pointer can be set to NULL if it is not required.
90 * This function is designed to avoid exposing timing channels on token values
91 * or the contents of the SRT mapping.
93 * If there are several identical SRTs, idx can be used to get the nth entry.
94 * Call this function with idx set to 0 first, and keep calling it after
95 * incrementing idx until it returns 0.
97 * Returns 1 if an entry was found and 0 otherwise.
99 int ossl_quic_srtm_lookup(QUIC_SRTM *srtm,
100 const QUIC_STATELESS_RESET_TOKEN *token,
102 void **opaque, uint64_t *seq_num);
104 /* Verify internal invariants and assert if they are not met. */
105 void ossl_quic_srtm_check(const QUIC_SRTM *srtm);