2 * Copyright 2022-2023 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_QUIC_RECORD_TX_H
11 # define OSSL_QUIC_RECORD_TX_H
13 # include <openssl/ssl.h>
14 # include "internal/quic_wire_pkt.h"
15 # include "internal/quic_types.h"
16 # include "internal/quic_predef.h"
17 # include "internal/quic_record_util.h"
19 # ifndef OPENSSL_NO_QUIC
22 * QUIC Record Layer - TX
23 * ======================
25 typedef struct ossl_qtx_iovec_st {
26 const unsigned char *buf;
30 typedef struct ossl_qtx_st OSSL_QTX;
32 typedef int (*ossl_mutate_packet_cb)(const QUIC_PKT_HDR *hdrin,
33 const OSSL_QTX_IOVEC *iovecin, size_t numin,
34 QUIC_PKT_HDR **hdrout,
35 const OSSL_QTX_IOVEC **iovecout,
39 typedef void (*ossl_finish_mutate_cb)(void *arg);
41 typedef struct ossl_qtx_args_st {
45 /* BIO to transmit to. */
48 /* Maximum datagram payload length (MDPL) for TX purposes. */
52 /* Instantiates a new QTX. */
53 OSSL_QTX *ossl_qtx_new(const OSSL_QTX_ARGS *args);
56 void ossl_qtx_free(OSSL_QTX *qtx);
58 /* Set mutator callbacks for test framework support */
59 void ossl_qtx_set_mutator(OSSL_QTX *qtx, ossl_mutate_packet_cb mutatecb,
60 ossl_finish_mutate_cb finishmutatecb, void *mutatearg);
62 /* Setters for the msg_callback and the msg_callback_arg */
63 void ossl_qtx_set_msg_callback(OSSL_QTX *qtx, ossl_msg_cb msg_callback,
64 SSL *msg_callback_ssl);
65 void ossl_qtx_set_msg_callback_arg(OSSL_QTX *qtx, void *msg_callback_arg);
73 * Provides a secret to the QTX, which arises due to an encryption level change.
74 * enc_level is a QUIC_ENC_LEVEL_* value.
76 * This function can be used to initialise the INITIAL encryption level, but you
77 * should not do so directly; see the utility function
78 * ossl_qrl_provide_initial_secret() instead, which can initialise the INITIAL
79 * encryption level of a QRX and QTX simultaneously without duplicating certain
80 * key derivation steps.
82 * You must call this function for a given EL before transmitting packets at
83 * that EL using this QTX, otherwise ossl_qtx_write_pkt will fail.
85 * suite_id is a QRL_SUITE_* value which determines the AEAD function used for
88 * The secret passed is used directly to derive the "quic key", "quic iv" and
91 * secret_len is the length of the secret buffer in bytes. The buffer must be
92 * sized correctly to the chosen suite, else the function fails.
94 * This function can only be called once for a given EL, except for the INITIAL
95 * EL, as the INITIAL EL can need to be rekeyed if connection retry occurs.
96 * Subsequent calls for non-INITIAL ELs fail. Calls made after a corresponding
97 * call to ossl_qtx_discard_enc_level for a given EL also fail, including for
98 * the INITIAL EL. The secret for a non-INITIAL EL cannot be changed after it is
99 * set because QUIC has no facility for introducing additional key material
100 * after an EL is setup. (QUIC key updates generate new keys from existing key
101 * material and do not introduce new entropy into a connection's key material.)
103 * Returns 1 on success or 0 on failure.
105 int ossl_qtx_provide_secret(OSSL_QTX *qtx,
109 const unsigned char *secret,
113 * Informs the QTX that it can now discard key material for a given EL. The QTX
114 * will no longer be able to generate packets at that EL. This function is
115 * idempotent and succeeds if the EL has already been discarded.
117 * Returns 1 on success and 0 on failure.
119 int ossl_qtx_discard_enc_level(OSSL_QTX *qtx, uint32_t enc_level);
121 /* Returns 1 if the given encryption level is provisioned. */
122 int ossl_qtx_is_enc_level_provisioned(OSSL_QTX *qtx, uint32_t enc_level);
125 * Given the value ciphertext_len representing an encrypted packet payload
126 * length in bytes, determines how many plaintext bytes it will decrypt to.
127 * Returns 0 if the specified EL is not provisioned or ciphertext_len is too
128 * small. The result is written to *plaintext_len.
130 int ossl_qtx_calculate_plaintext_payload_len(OSSL_QTX *qtx, uint32_t enc_level,
131 size_t ciphertext_len,
132 size_t *plaintext_len);
135 * Given the value plaintext_len represented a plaintext packet payload length
136 * in bytes, determines how many ciphertext bytes it will encrypt to. The value
137 * output does not include packet headers. Returns 0 if the specified EL is not
138 * provisioned. The result is written to *ciphertext_len.
140 int ossl_qtx_calculate_ciphertext_payload_len(OSSL_QTX *qtx, uint32_t enc_level,
141 size_t plaintext_len,
142 size_t *ciphertext_len);
144 uint32_t ossl_qrl_get_suite_cipher_tag_len(uint32_t suite_id);
148 * Packet Transmission
149 * -------------------
152 struct ossl_qtx_pkt_st {
153 /* Logical packet header to be serialized. */
157 * iovecs expressing the logical packet payload buffer. Zero-length entries
160 const OSSL_QTX_IOVEC *iovec;
163 /* Destination address. Will be passed through to the BIO if non-NULL. */
164 const BIO_ADDR *peer;
167 * Local address (optional). Specify as non-NULL only if TX BIO
168 * has local address support enabled.
170 const BIO_ADDR *local;
173 * Logical PN. Used for encryption. This will automatically be encoded to
174 * hdr->pn, which need not be initialized.
178 /* Packet flags. Zero or more OSSL_QTX_PKT_FLAG_* values. */
183 * More packets will be written which should be coalesced into a single
184 * datagram; do not send this packet yet. To use this, set this flag for all
185 * packets but the final packet in a datagram, then send the final packet
186 * without this flag set.
188 * This flag is not a guarantee and the QTX may transmit immediately anyway if
189 * it is not possible to fit any more packets in the current datagram.
191 * If the caller change its mind and needs to cause a packet queued with
192 * COALESCE after having passed it to this function but without writing another
193 * packet, it should call ossl_qtx_flush_pkt().
195 #define OSSL_QTX_PKT_FLAG_COALESCE (1U << 0)
200 * *pkt need be valid only for the duration of the call to this function.
202 * pkt->hdr->data and pkt->hdr->len are unused. The payload buffer is specified
203 * via an array of OSSL_QTX_IOVEC structures. The API is designed to support
204 * single-copy transmission; data is copied from the iovecs as it is encrypted
205 * into an internal staging buffer for transmission.
207 * The function may modify and clobber pkt->hdr->data, pkt->hdr->len,
208 * pkt->hdr->key_phase and pkt->hdr->pn for its own internal use. No other
209 * fields of pkt or pkt->hdr will be modified.
211 * It is the callers responsibility to determine how long the PN field in the
212 * encoded packet should be by setting pkt->hdr->pn_len. This function takes
213 * care of the PN encoding. Set pkt->pn to the desired PN.
215 * Note that 1-RTT packets do not have a DCID Length field, therefore the DCID
216 * length must be understood contextually. This function assumes the caller
217 * knows what it is doing and will serialize a DCID of whatever length is given.
218 * It is the caller's responsibility to ensure it uses a consistent DCID length
219 * for communication with any given set of remote peers.
221 * The packet is queued regardless of whether it is able to be sent immediately.
222 * This enables packets to be batched and sent at once on systems which support
223 * system calls to send multiple datagrams in a single system call (see
224 * BIO_sendmmsg). To flush queued datagrams to the network, see
225 * ossl_qtx_flush_net().
227 * Returns 1 on success or 0 on failure.
229 int ossl_qtx_write_pkt(OSSL_QTX *qtx, const OSSL_QTX_PKT *pkt);
232 * Finish any incomplete datagrams for transmission which were flagged for
233 * coalescing. If there is no current coalescing datagram, this is a no-op.
235 void ossl_qtx_finish_dgram(OSSL_QTX *qtx);
238 * (Attempt to) flush any datagrams which are queued for transmission. Note that
239 * this does not cancel coalescing; call ossl_qtx_finish_dgram() first if that
240 * is desired. The queue is drained into the OS's sockets as much as possible.
241 * To determine if there is still data to be sent after calling this function,
242 * use ossl_qtx_get_queue_len_bytes().
244 * Returns one of the following values:
246 * QTX_FLUSH_NET_RES_OK
247 * Either no packets are currently queued for transmission,
248 * or at least one packet was successfully submitted.
250 * QTX_FLUSH_NET_RES_TRANSIENT_FAIL
251 * The underlying network write BIO indicated a transient error
252 * (e.g. buffers full).
254 * QTX_FLUSH_NET_RES_PERMANENT_FAIL
255 * Internal error (e.g. assertion or allocation error)
256 * or the underlying network write BIO indicated a non-transient
259 #define QTX_FLUSH_NET_RES_OK 1
260 #define QTX_FLUSH_NET_RES_TRANSIENT_FAIL (-1)
261 #define QTX_FLUSH_NET_RES_PERMANENT_FAIL (-2)
263 int ossl_qtx_flush_net(OSSL_QTX *qtx);
266 * Diagnostic function. If there is any datagram pending transmission, pops it
267 * and writes the details of the datagram as they would have been passed to
268 * *msg. Returns 1, or 0 if there are no datagrams pending. For test use only.
270 int ossl_qtx_pop_net(OSSL_QTX *qtx, BIO_MSG *msg);
272 /* Returns number of datagrams which are fully-formed but not yet sent. */
273 size_t ossl_qtx_get_queue_len_datagrams(OSSL_QTX *qtx);
276 * Returns number of payload bytes across all datagrams which are fully-formed
277 * but not yet sent. Does not count any incomplete coalescing datagram.
279 size_t ossl_qtx_get_queue_len_bytes(OSSL_QTX *qtx);
282 * Returns number of bytes in the current coalescing datagram, or 0 if there is
283 * no current coalescing datagram. Returns 0 after a call to
284 * ossl_qtx_finish_dgram().
286 size_t ossl_qtx_get_cur_dgram_len_bytes(OSSL_QTX *qtx);
289 * Returns number of queued coalesced packets which have not been put into a
290 * datagram yet. If this is non-zero, ossl_qtx_flush_pkt() needs to be called.
292 size_t ossl_qtx_get_unflushed_pkt_count(OSSL_QTX *qtx);
295 * Change the BIO being used by the QTX. May be NULL if actual transmission is
296 * not currently required. Does not up-ref the BIO; the caller is responsible
297 * for ensuring the lifetime of the BIO exceeds the lifetime of the QTX.
299 void ossl_qtx_set_bio(OSSL_QTX *qtx, BIO *bio);
301 /* Changes the MDPL. */
302 int ossl_qtx_set_mdpl(OSSL_QTX *qtx, size_t mdpl);
304 /* Retrieves the current MDPL. */
305 size_t ossl_qtx_get_mdpl(OSSL_QTX *qtx);
312 * For additional discussion of key update considerations, see QRX header file.
316 * Triggers a key update. The key update will be started by inverting the Key
317 * Phase bit of the next packet transmitted; no key update occurs until the next
318 * packet is transmitted. Thus, this function should generally be called
319 * immediately before queueing the next packet.
321 * There are substantial requirements imposed by RFC 9001 on under what
322 * circumstances a key update can be initiated. The caller is responsible for
323 * meeting most of these requirements. For example, this function cannot be
324 * called too soon after a previous key update has occurred. Key updates also
325 * cannot be initiated until the 1-RTT encryption level is reached.
327 * As a sanity check, this function will fail and return 0 if the non-1RTT
328 * encryption levels have not yet been dropped.
330 * The caller may decide itself to initiate a key update, but it also MUST
331 * initiate a key update where it detects that the peer has initiated a key
332 * update. The caller is responsible for initiating a TX key update by calling
333 * this function in this circumstance; thus, the caller is responsible for
334 * coupling the RX and TX QUIC record layers in this way.
336 int ossl_qtx_trigger_key_update(OSSL_QTX *qtx);
345 * Returns the number of packets which have been encrypted for transmission with
346 * the current set of TX keys (the current "TX key epoch"). Reset to zero after
347 * a key update and incremented for each packet queued. If enc_level is not
348 * valid or relates to an EL which is not currently available, returns
351 uint64_t ossl_qtx_get_cur_epoch_pkt_count(OSSL_QTX *qtx, uint32_t enc_level);
354 * Returns the maximum number of packets which the record layer will permit to
355 * be encrypted using the current set of TX keys. If this limit is reached (that
356 * is, if the counter returned by ossl_qrx_tx_get_cur_epoch_pkt_count() reaches
357 * this value), as a safety measure, the QTX will not permit any further packets
358 * to be queued. All calls to ossl_qrx_write_pkt that try to send packets of a
359 * kind which need to be encrypted will fail. It is not possible to recover from
360 * this condition and the QTX must then be destroyed; therefore, callers should
361 * ensure they always trigger a key update well in advance of reaching this
364 * The value returned by this function is based on the ciphersuite configured
365 * for the given encryption level. If keys have not been provisioned for the
366 * specified enc_level or the enc_level argument is invalid, this function
367 * returns UINT64_MAX, which is not a valid value. Note that it is not possible
368 * to perform a key update at any encryption level other than 1-RTT, therefore
369 * if this limit is reached at earlier encryption levels (which should not be
370 * possible) the connection must be terminated. Since this condition precludes
371 * the transmission of further packets, the only possible signalling of such an
372 * error condition to a peer is a Stateless Reset packet.
374 uint64_t ossl_qtx_get_max_epoch_pkt_count(OSSL_QTX *qtx, uint32_t enc_level);
377 * Get the 1-RTT EL key epoch number for the QTX. This is intended for
378 * diagnostic purposes. Returns 0 if 1-RTT EL is not provisioned yet.
380 uint64_t ossl_qtx_get_key_epoch(OSSL_QTX *qtx);