openssl/ssl/record/recordmethod.h
Matt Caswell 11653dcd6e Fix compilation issues in the imported recordmethod.h
Also, rename the "new" function pointer to "new_record_layer" to avoid a
C++ reserved name

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18132)
2022-08-18 16:38:12 +01:00

240 lines
10 KiB
C

/*
* Copyright 2022 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
*/
#include <openssl/ssl.h>
/*
* We use the term "record" here to refer to a packet of data. Records are
* typically protected via a cipher and MAC, or an AEAD cipher (although not
* always). This usage of the term record is consistent with the TLS concept.
* In QUIC the term "record" is not used but it is analogous to the QUIC term
* "packet". The interface in this file applies to all protocols that protect
* records/packets of data, i.e. (D)TLS and QUIC. The term record is used to
* refer to both contexts.
*/
/*
* Types of QUIC record layer;
*
* QUIC reuses the TLS handshake for agreeing secrets. An SSL object representing
* a QUIC connection will have an additional SSL object internally representing
* the TLS state of the QUIC handshake. This internal TLS is referred to as
* QUIC-TLS in this file.
* "Records" output from QUIC-TLS contains standard TLS handshake messages and
* are *not* encrypted directly but are instead wrapped up in plaintext
* CRYPTO frames. These CRYPTO frames could be collected together with other
* QUIC frames into a single QUIC packet. The QUIC record layer will then
* encrypt the whole packet.
*
* So we have:
* QUIC-TLS record layer: outputs plaintext CRYPTO frames containing TLS
* handshake messages only.
* QUIC record layer: outputs encrypted packets which may contain CRYPTO frames
* or any other type of QUIC frame.
*/
/*
* An OSSL_RECORD_METHOD is a protcol specific method which provides the
* functions for reading and writing records for that protocol. Which
* OSSL_RECORD_METHOD to use for a given protocol is defined by the SSL_METHOD.
*/
typedef struct ossl_record_method_st OSSL_RECORD_METHOD;
/*
* An OSSL_RECORD_LAYER is just an externally defined opaque pointer created by
* the method
*/
typedef struct ossl_record_layer_st OSSL_RECORD_LAYER;
#define OSSL_RECORD_ROLE_CLIENT 0
#define OSSL_RECORD_ROLE_SERVER 1
#define OSSL_RECORD_DIRECTION_READ 0
#define OSSL_RECORD_DIRECTION_WRITE 1
/*
* Protection level. For <= TLSv1.2 only "NONE" and "APPLICATION" are used.
*/
#define OSSL_RECORD_PROTECTION_LEVEL_NONE 0
#define OSSL_RECORD_PROTECTION_LEVEL_EARLY 1
#define OSSL_RECORD_PROTECTION_LEVEL_HANDSHAKE 2
#define OSSL_RECORD_PROTECTION_LEVEL_APPLICATION 3
/*
* Template for creating a record. A record consists of the |type| of data it
* will contain (e.g. alert, handshake, application data, etc) along with an
* array of buffers in |bufs| of size |numbufs|. There is a corresponding array
* of buffer lengths in |buflens|. Concatenating all of the buffer data together
* would give you the complete plaintext payload to be sent in a single record.
*/
struct ossl_record_template_st {
int type;
void **bufs;
size_t *buflens;
size_t numbufs;
};
typedef struct ossl_record_template_st OSSL_RECORD_TEMPLATE;
/*
* Rather than a "method" approach, we could make this fetchable - Should we?
* There could be some complexity in finding suitable record layer implementations
* e.g. we need to find one that matches the negotiated protocol, cipher,
* extensions, etc. The selection_cb approach given above doesn't work so well
* if unknown third party providers with OSSL_RECORD_METHOD implementations are
* loaded.
*/
/*
* If this becomes public API then we will need functions to create and
* free an OSSL_RECORD_METHOD, as well as functions to get/set the various
* function pointers....unless we make it fetchable.
*/
struct ossl_record_method_st {
/*
* Create a new OSSL_RECORD_LAYER object for handling the protocol version
* set by |vers|. |role| is 0 for client and 1 for server. |direction|
* indicates either read or write. |level| is the protection level as
* described above. |settings| are mandatory settings that will cause the
* new() call to fail if they are not understood (for example to require
* Encrypt-Then-Mac support). |options| are optional settings that will not
* cause the new() call to fail if they are not understood (for example
* whether to use "read ahead" or not).
*
* The BIO in |transport| is the BIO for the underlying transport layer.
* Where the direction is "read", then this BIO will only ever be used for
* reading data. Where the direction is "write", then this BIO will only
* every be used for writing data.
*
* An SSL object will always have at least 2 OSSL_RECORD_LAYER objects in
* force at any one time (one for reading and one for writing). In some
* protocols more than 2 might be used (e.g. in DTLS for retransmitting
* messages from an earlier epoch).
*/
/*
* TODO: Will have to be something other than SSL_CIPHER if we make this
* fetchable
*/
OSSL_RECORD_LAYER *(*new_record_layer)(int vers, int role, int direction,
int level, unsigned char *secret,
size_t secretlen, SSL_CIPHER *c,
BIO *transport, BIO_ADDR *local,
BIO_ADDR *peer, OSSL_PARAM *settings,
OSSL_PARAM *options);
void (*free)(OSSL_RECORD_LAYER *rl);
int (*reset)(OSSL_RECORD_LAYER *rl); /* Is this needed? */
/* Returns 1 if we have unprocessed data buffered or 0 otherwise */
int (*unprocessed_read_pending)(OSSL_RECORD_LAYER *rl);
/*
* Returns 1 if we have processed data buffered that can be read or 0 otherwise
* - not necessarily app data
*/
int (*processed_read_pending)(OSSL_RECORD_LAYER *rl);
/*
* The amount of processed app data that is internally bufferred and
* available to read
*/
size_t (*app_data_pending)(OSSL_RECORD_LAYER *rl);
int (*write_pending)(OSSL_RECORD_LAYER *rl);
/*
* Find out the maximum amount of plaintext data that the record layer is
* prepared to write in a single record. When calling write_records it is
* the caller's responsibility to ensure that no record template exceeds
* this maximum when calling write_records.
*/
size_t (*get_max_record_len)(OSSL_RECORD_LAYER *rl);
/*
* Find out the maximum number of records that the record layer is prepared
* to process in a single call to write_records. It is the caller's
* responsibility to ensure that no call to write_records exceeds this
* number of records.
*/
size_t (*get_max_records)(OSSL_RECORD_LAYER *rl);
/*
* Write |numtempl| records from the array of record templates pointed to
* by |templates|. Each record should be no longer than the value returned
* by get_max_record_len(), and there should be no more records than the
* value returned by get_max_records().
* |allowance| is the maximum amount of "on-the-wire" data that is allowed
* to be sent at the moment (including all QUIC headers, but excluding any
* UDP/IP headers). After a successful or retry return |*sent| will
* be updated with the amount of data that has been sent so far. In the case
* of a retry this could be 0.
* Where possible the caller will attempt to ensure that all records are the
* same length, except the last record. This may not always be possible so
* the record method implementation should not rely on this being the case.
* In the event of a retry the caller should call retry_write_records()
* to try again. No more calls to write_records() should be attempted until
* retry_write_records() returns success.
* Buffers allocated for the record templates can be freed immediately after
* write_records() returns - even in the case a retry.
* The record templates represent the plaintext payload. The encrypted
* output is written to the |transport| BIO.
* Returns:
* 1 on success
* 0 on retry
* -1 on failure
*/
int (*write_records)(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE **templates,
size_t numtempl, size_t allowance, size_t *sent);
/*
* Retry a previous call to write_records. The caller should continue to
* call this until the function returns with success or failure. After
* each retry more of the data may have been incrementally sent. |allowance|
* is the amount of "on-the-wire" data that is allowed to be sent at the
* moment. After a successful or retry return |*sent| will
* be updated with the amount of data that has been sent by this call to
* retry_write_records().
* Returns:
* 1 on success
* 0 on retry
* -1 on failure
*/
int (*retry_write_records)(OSSL_RECORD_LAYER *rl, size_t allowance,
size_t *sent);
/*
* Read a record and return the record layer version and record type in
* the |rversion| and |type| parameters. |*data| is set to point to a
* record layer buffer containing the record payload data and |*datalen|
* is filled in with the length of that data. The |epoch| and |seq_num|
* values are only used if DTLS has been negotiated. In that case they are
* filled in with the epoch and sequence number from the record.
* An opaque record layer handle for the record is returned in |*rechandle|
* which is used in a subsequent call to |release_record|. The buffer must
* remain available until release_record is called.
*
* Internally the the OSSL_RECORD_METHOD the implementation may read/process
* multiple records in one go and buffer them.
*/
int (*read_record)(OSSL_RECORD_LAYER *rl, void **rechandle, int *rversion,
int *type, unsigned char **data, size_t *datalen,
uint16_t *epoch, unsigned char *seq_num);
/*
* Release a buffer associated with a record previously read with
* read_record. Records are guaranteed to be released in the order that they
* are read.
*/
void (*release_record)(OSSL_RECORD_LAYER *rl, void *rechandle);
};