/* * 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 */ #ifndef OSSL_QUIC_RECORD_TX_H # define OSSL_QUIC_RECORD_TX_H # include # include "internal/quic_wire_pkt.h" # include "internal/quic_types.h" # include "internal/quic_record_util.h" # ifndef OPENSSL_NO_QUIC /* * QUIC Record Layer - TX * ====================== */ typedef struct ossl_qtx_st OSSL_QTX; typedef struct ossl_qtx_args_st { OSSL_LIB_CTX *libctx; const char *propq; /* BIO to transmit to. */ BIO *bio; /* Maximum datagram payload length (MDPL) for TX purposes. */ size_t mdpl; } OSSL_QTX_ARGS; /* Instantiates a new QTX. */ OSSL_QTX *ossl_qtx_new(const OSSL_QTX_ARGS *args); /* Frees the QTX. */ void ossl_qtx_free(OSSL_QTX *qtx); /* * Secret Management * ----------------- */ /* * Provides a secret to the QTX, which arises due to an encryption level change. * enc_level is a QUIC_ENC_LEVEL_* value. * * This function can be used to initialise the INITIAL encryption level, but you * should not do so directly; see the utility function * ossl_qrl_provide_initial_secret() instead, which can initialise the INITIAL * encryption level of a QRX and QTX simultaneously without duplicating certain * key derivation steps. * * You must call this function for a given EL before transmitting packets at * that EL using this QTX, otherwise ossl_qtx_write_pkt will fail. * * suite_id is a QRL_SUITE_* value which determines the AEAD function used for * the QTX. * * The secret passed is used directly to derive the "quic key", "quic iv" and * "quic hp" values. * * secret_len is the length of the secret buffer in bytes. The buffer must be * sized correctly to the chosen suite, else the function fails. * * This function can only be called once for a given EL, except for the INITIAL * EL, as the INITIAL EL can need to be rekeyed if connection retry occurs. * Subsequent calls for non-INITIAL ELs fail. Calls made after a corresponding * call to ossl_qtx_discard_enc_level for a given EL also fail, including for * the INITIAL EL. The secret for a non-INITIAL EL cannot be changed after it is * set because QUIC has no facility for introducing additional key material * after an EL is setup. (QUIC key updates generate new keys from existing key * material and do not introduce new entropy into a connection's key material.) * * Returns 1 on success or 0 on failure. */ int ossl_qtx_provide_secret(OSSL_QTX *qtx, uint32_t enc_level, uint32_t suite_id, EVP_MD *md, const unsigned char *secret, size_t secret_len); /* * Informs the QTX that it can now discard key material for a given EL. The QTX * will no longer be able to generate packets at that EL. This function is * idempotent and succeeds if the EL has already been discarded. * * Returns 1 on success and 0 on failure. */ int ossl_qtx_discard_enc_level(OSSL_QTX *qtx, uint32_t enc_level); /* Returns 1 if the given encryption level is provisioned. */ int ossl_qtx_is_enc_level_provisioned(OSSL_QTX *qtx, uint32_t enc_level); /* * Given the value ciphertext_len representing an encrypted packet payload * length in bytes, determines how many plaintext bytes it will decrypt to. * Returns 0 if the specified EL is not provisioned or ciphertext_len is too * small. The result is written to *plaintext_len. */ int ossl_qtx_calculate_plaintext_payload_len(OSSL_QTX *qtx, uint32_t enc_level, size_t ciphertext_len, size_t *plaintext_len); uint32_t ossl_qrl_get_suite_cipher_tag_len(uint32_t suite_id); /* * Packet Transmission * ------------------- */ typedef struct ossl_qtx_iovec_st { const unsigned char *buf; size_t buf_len; } OSSL_QTX_IOVEC; typedef struct ossl_qtx_pkt_st { /* Logical packet header to be serialized. */ QUIC_PKT_HDR *hdr; /* * iovecs expressing the logical packet payload buffer. Zero-length entries * are permitted. */ const OSSL_QTX_IOVEC *iovec; size_t num_iovec; /* Destination address. Will be passed through to the BIO if non-NULL. */ const BIO_ADDR *peer; /* * Local address (optional). Specify as non-NULL only if TX BIO * has local address support enabled. */ const BIO_ADDR *local; /* * Logical PN. Used for encryption. This will automatically be encoded to * hdr->pn, which need not be initialized. */ QUIC_PN pn; /* Packet flags. Zero or more OSSL_QTX_PKT_FLAG_* values. */ uint32_t flags; } OSSL_QTX_PKT; /* * More packets will be written which should be coalesced into a single * datagram; do not send this packet yet. To use this, set this flag for all * packets but the final packet in a datagram, then send the final packet * without this flag set. * * This flag is not a guarantee and the QTX may transmit immediately anyway if * it is not possible to fit any more packets in the current datagram. * * If the caller change its mind and needs to cause a packet queued with * COALESCE after having passed it to this function but without writing another * packet, it should call ossl_qtx_flush_pkt(). */ #define OSSL_QTX_PKT_FLAG_COALESCE (1U << 0) /* * Writes a packet. * * *pkt need be valid only for the duration of the call to this function. * * pkt->hdr->data and pkt->hdr->len are unused. The payload buffer is specified * via an array of OSSL_QTX_IOVEC structures. The API is designed to support * single-copy transmission; data is copied from the iovecs as it is encrypted * into an internal staging buffer for transmission. * * The function may modify and clobber pkt->hdr->data, pkt->hdr->len, * pkt->hdr->key_phase and pkt->hdr->pn for its own internal use. No other * fields of pkt or pkt->hdr will be modified. * * It is the callers responsibility to determine how long the PN field in the * encoded packet should be by setting pkt->hdr->pn_len. This function takes * care of the PN encoding. Set pkt->pn to the desired PN. * * Note that 1-RTT packets do not have a DCID Length field, therefore the DCID * length must be understood contextually. This function assumes the caller * knows what it is doing and will serialize a DCID of whatever length is given. * It is the caller's responsibility to ensure it uses a consistent DCID length * for communication with any given set of remote peers. * * The packet is queued regardless of whether it is able to be sent immediately. * This enables packets to be batched and sent at once on systems which support * system calls to send multiple datagrams in a single system call (see * BIO_sendmmsg). To flush queued datagrams to the network, see * ossl_qtx_flush_net(). * * Returns 1 on success or 0 on failure. */ int ossl_qtx_write_pkt(OSSL_QTX *qtx, const OSSL_QTX_PKT *pkt); /* * Finish any incomplete datagrams for transmission which were flagged for * coalescing. If there is no current coalescing datagram, this is a no-op. */ void ossl_qtx_finish_dgram(OSSL_QTX *qtx); /* * (Attempt to) flush any datagrams which are queued for transmission. Note that * this does not cancel coalescing; call ossl_qtx_finish_dgram() first if that * is desired. The queue is drained into the OS's sockets as much as possible. * To determine if there is still data to be sent after calling this function, * use ossl_qtx_get_queue_len_bytes(). * * Returns one of the following values: * * QTX_FLUSH_NET_RES_OK * Either no packets are currently queued for transmission, * or at least one packet was successfully submitted. * * QTX_FLUSH_NET_RES_TRANSIENT_FAIL * The underlying network write BIO indicated a transient error * (e.g. buffers full). * * QTX_FLUSH_NET_RES_PERMANENT_FAIL * Internal error (e.g. assertion or allocation error) * or the underlying network write BIO indicated a non-transient * error. */ #define QTX_FLUSH_NET_RES_OK 1 #define QTX_FLUSH_NET_RES_TRANSIENT_FAIL (-1) #define QTX_FLUSH_NET_RES_PERMANENT_FAIL (-2) int ossl_qtx_flush_net(OSSL_QTX *qtx); /* * Diagnostic function. If there is any datagram pending transmission, pops it * and writes the details of the datagram as they would have been passed to * *msg. Returns 1, or 0 if there are no datagrams pending. For test use only. */ int ossl_qtx_pop_net(OSSL_QTX *qtx, BIO_MSG *msg); /* Returns number of datagrams which are fully-formed but not yet sent. */ size_t ossl_qtx_get_queue_len_datagrams(OSSL_QTX *qtx); /* * Returns number of payload bytes across all datagrams which are fully-formed * but not yet sent. Does not count any incomplete coalescing datagram. */ size_t ossl_qtx_get_queue_len_bytes(OSSL_QTX *qtx); /* * Returns number of bytes in the current coalescing datagram, or 0 if there is * no current coalescing datagram. Returns 0 after a call to * ossl_qtx_finish_dgram(). */ size_t ossl_qtx_get_cur_dgram_len_bytes(OSSL_QTX *qtx); /* * Returns number of queued coalesced packets which have not been put into a * datagram yet. If this is non-zero, ossl_qtx_flush_pkt() needs to be called. */ size_t ossl_qtx_get_unflushed_pkt_count(OSSL_QTX *qtx); /* * Change the BIO being used by the QTX. May be NULL if actual transmission is * not currently required. Does not up-ref the BIO; the caller is responsible * for ensuring the lifetime of the BIO exceeds the lifetime of the QTX. */ void ossl_qtx_set_bio(OSSL_QTX *qtx, BIO *bio); /* Changes the MDPL. */ int ossl_qtx_set_mdpl(OSSL_QTX *qtx, size_t mdpl); /* Retrieves the current MDPL. */ size_t ossl_qtx_get_mdpl(OSSL_QTX *qtx); /* * Key Update * ---------- * * For additional discussion of key update considerations, see QRX header file. */ /* * Triggers a key update. The key update will be started by inverting the Key * Phase bit of the next packet transmitted; no key update occurs until the next * packet is transmitted. Thus, this function should generally be called * immediately before queueing the next packet. * * There are substantial requirements imposed by RFC 9001 on under what * circumstances a key update can be initiated. The caller is responsible for * meeting most of these requirements. For example, this function cannot be * called too soon after a previous key update has occurred. Key updates also * cannot be initiated until the 1-RTT encryption level is reached. * * As a sanity check, this function will fail and return 0 if the non-1RTT * encryption levels have not yet been dropped. * * The caller may decide itself to initiate a key update, but it also MUST * initiate a key update where it detects that the peer has initiated a key * update. The caller is responsible for initiating a TX key update by calling * this function in this circumstance; thus, the caller is responsible for * coupling the RX and TX QUIC record layers in this way. */ int ossl_qtx_trigger_key_update(OSSL_QTX *qtx); /* * Key Expiration * -------------- */ /* * Returns the number of packets which have been encrypted for transmission with * the current set of TX keys (the current "TX key epoch"). Reset to zero after * a key update and incremented for each packet queued. If enc_level is not * valid or relates to an EL which is not currently available, returns * UINT64_MAX. */ uint64_t ossl_qtx_get_cur_epoch_pkt_count(OSSL_QTX *qtx, uint32_t enc_level); /* * Returns the maximum number of packets which the record layer will permit to * be encrypted using the current set of TX keys. If this limit is reached (that * is, if the counter returned by ossl_qrx_tx_get_cur_epoch_pkt_count() reaches * this value), as a safety measure, the QTX will not permit any further packets * to be queued. All calls to ossl_qrx_write_pkt that try to send packets of a * kind which need to be encrypted will fail. It is not possible to recover from * this condition and the QTX must then be destroyed; therefore, callers should * ensure they always trigger a key update well in advance of reaching this * limit. * * The value returned by this function is based on the ciphersuite configured * for the given encryption level. If keys have not been provisioned for the * specified enc_level or the enc_level argument is invalid, this function * returns UINT64_MAX, which is not a valid value. Note that it is not possible * to perform a key update at any encryption level other than 1-RTT, therefore * if this limit is reached at earlier encryption levels (which should not be * possible) the connection must be terminated. Since this condition precludes * the transmission of further packets, the only possible signalling of such an * error condition to a peer is a Stateless Reset packet. */ uint64_t ossl_qtx_get_max_epoch_pkt_count(OSSL_QTX *qtx, uint32_t enc_level); # endif #endif