Adding upstream version 3.2.6.upstream/3.2.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 893 insertions, 0 deletions

diff --git a/src/contrib/libngtcp2/ngtcp2/ngtcp2_crypto.h b/src/contrib/libngtcp2/ngtcp2/ngtcp2_crypto.h
new file mode 100644
index 0000000..4736b51
--- /dev/null
+++ b/src/contrib/libngtcp2/ngtcp2/ngtcp2_crypto.h
@@ -0,0 +1,893 @@
+/*
+ * ngtcp2
+ *
+ * Copyright (c) 2019 ngtcp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef NGTCP2_CRYPTO_H
+#define NGTCP2_CRYPTO_H
+
+#include <ngtcp2/ngtcp2.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef WIN32
+#  ifndef WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
+#  endif
+#  include <ws2tcpip.h>
+#endif /* WIN32 */
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_INITIAL_SECRETLEN` is the length of secret
+ * for Initial packets.
+ */
+#define NGTCP2_CRYPTO_INITIAL_SECRETLEN 32
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_INITIAL_KEYLEN` is the length of key for
+ * Initial packets.
+ */
+#define NGTCP2_CRYPTO_INITIAL_KEYLEN 16
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_INITIAL_IVLEN` is the length of IV for
+ * Initial packets.
+ */
+#define NGTCP2_CRYPTO_INITIAL_IVLEN 12
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_ctx_tls` initializes |ctx| by extracting negotiated
+ * ciphers and message digests from native TLS session
+ * |tls_native_handle|.  This is used for encrypting/decrypting
+ * Handshake and Short header packets.
+ *
+ * If libngtcp2_crypto_openssl is linked, |tls_native_handle| must be
+ * a pointer to SSL object.
+ */
+NGTCP2_EXTERN ngtcp2_crypto_ctx *ngtcp2_crypto_ctx_tls(ngtcp2_crypto_ctx *ctx,
+                                                       void *tls_native_handle);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_ctx_tls_early` initializes |ctx| by extracting early
+ * ciphers and message digests from native TLS session
+ * |tls_native_handle|.  This is used for encrypting/decrypting 0RTT
+ * packets.
+ *
+ * If libngtcp2_crypto_openssl is linked, |tls_native_handle| must be
+ * a pointer to SSL object.
+ */
+NGTCP2_EXTERN ngtcp2_crypto_ctx *
+ngtcp2_crypto_ctx_tls_early(ngtcp2_crypto_ctx *ctx, void *tls_native_handle);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_md_init` initializes |md| with the provided
+ * |md_native_handle| which is an underlying message digest object.
+ *
+ * If libngtcp2_crypto_openssl is linked, |md_native_handle| must be a
+ * pointer to EVP_MD.
+ *
+ * If libngtcp2_crypto_gnutls is linked, |md_native_handle| must be
+ * gnutls_mac_algorithm_t casted to ``void *``.
+ *
+ * If libngtcp2_crypto_boringssl is linked, |md_native_handle| must be
+ * a pointer to EVP_MD.
+ */
+NGTCP2_EXTERN ngtcp2_crypto_md *ngtcp2_crypto_md_init(ngtcp2_crypto_md *md,
+                                                      void *md_native_handle);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_md_hashlen` returns the length of |md| output.
+ */
+NGTCP2_EXTERN size_t ngtcp2_crypto_md_hashlen(const ngtcp2_crypto_md *md);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_aead_keylen` returns the length of key for |aead|.
+ */
+NGTCP2_EXTERN size_t ngtcp2_crypto_aead_keylen(const ngtcp2_crypto_aead *aead);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_aead_noncelen` returns the length of nonce for
+ * |aead|.
+ */
+NGTCP2_EXTERN size_t
+ngtcp2_crypto_aead_noncelen(const ngtcp2_crypto_aead *aead);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hkdf_extract` performs HKDF extract operation.  The
+ * result is the length of |md| and is stored to the buffer pointed by
+ * |dest|.  The caller is responsible to specify the buffer that can
+ * store the output.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_hkdf_extract(uint8_t *dest, const ngtcp2_crypto_md *md,
+                           const uint8_t *secret, size_t secretlen,
+                           const uint8_t *salt, size_t saltlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hkdf_expand` performs HKDF expand operation.  The
+ * result is |destlen| bytes long and is stored to the buffer pointed
+ * by |dest|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_hkdf_expand(uint8_t *dest, size_t destlen,
+                                            const ngtcp2_crypto_md *md,
+                                            const uint8_t *secret,
+                                            size_t secretlen,
+                                            const uint8_t *info,
+                                            size_t infolen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hkdf` performs HKDF operation.  The result is
+ * |destlen| bytes long and is stored to the buffer pointed by |dest|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_hkdf(uint8_t *dest, size_t destlen,
+                                     const ngtcp2_crypto_md *md,
+                                     const uint8_t *secret, size_t secretlen,
+                                     const uint8_t *salt, size_t saltlen,
+                                     const uint8_t *info, size_t infolen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hkdf_expand_label` performs HKDF expand label.  The
+ * result is |destlen| bytes long and is stored to the buffer pointed
+ * by |dest|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_hkdf_expand_label(uint8_t *dest, size_t destlen,
+                                                  const ngtcp2_crypto_md *md,
+                                                  const uint8_t *secret,
+                                                  size_t secretlen,
+                                                  const uint8_t *label,
+                                                  size_t labellen);
+
+/**
+ * @enum
+ *
+ * :type:`ngtcp2_crypto_side` indicates which side the application
+ * implements; client or server.
+ */
+typedef enum ngtcp2_crypto_side {
+  /**
+   * :enum:`NGTCP2_CRYPTO_SIDE_CLIENT` indicates that the application
+   * is client.
+   */
+  NGTCP2_CRYPTO_SIDE_CLIENT,
+  /**
+   * :enum:`NGTCP2_CRYPTO_SIDE_SERVER` indicates that the application
+   * is server.
+   */
+  NGTCP2_CRYPTO_SIDE_SERVER
+} ngtcp2_crypto_side;
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_packet_protection_ivlen` returns the length of IV
+ * used to encrypt QUIC packet.
+ */
+NGTCP2_EXTERN size_t
+ngtcp2_crypto_packet_protection_ivlen(const ngtcp2_crypto_aead *aead);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_encrypt` encrypts |plaintext| of length
+ * |plaintextlen| and writes the ciphertext into the buffer pointed by
+ * |dest|.  The length of ciphertext is plaintextlen +
+ * :member:`aead->max_overhead <ngtcp2_crypto_aead.max_overhead>`
+ * bytes long.  |dest| must have enough capacity to store the
+ * ciphertext.  It is allowed to specify the same value to |dest| and
+ * |plaintext|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_encrypt(uint8_t *dest,
+                                        const ngtcp2_crypto_aead *aead,
+                                        const ngtcp2_crypto_aead_ctx *aead_ctx,
+                                        const uint8_t *plaintext,
+                                        size_t plaintextlen,
+                                        const uint8_t *nonce, size_t noncelen,
+                                        const uint8_t *aad, size_t aadlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_encrypt_cb` is a wrapper function around
+ * `ngtcp2_crypto_encrypt`.  It can be directly passed to
+ * :member:`ngtcp2_callbacks.encrypt` field.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_encrypt_cb(uint8_t *dest, const ngtcp2_crypto_aead *aead,
+                         const ngtcp2_crypto_aead_ctx *aead_ctx,
+                         const uint8_t *plaintext, size_t plaintextlen,
+                         const uint8_t *nonce, size_t noncelen,
+                         const uint8_t *aad, size_t aadlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_decrypt` decrypts |ciphertext| of length
+ * |ciphertextlen| and writes the plaintext into the buffer pointed by
+ * |dest|.  The length of plaintext is ciphertextlen -
+ * :member:`aead->max_overhead <ngtcp2_crypto_aead.max_overhead>`
+ * bytes long.  |dest| must have enough capacity to store the
+ * plaintext.  It is allowed to specify the same value to |dest| and
+ * |ciphertext|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_decrypt(uint8_t *dest,
+                                        const ngtcp2_crypto_aead *aead,
+                                        const ngtcp2_crypto_aead_ctx *aead_ctx,
+                                        const uint8_t *ciphertext,
+                                        size_t ciphertextlen,
+                                        const uint8_t *nonce, size_t noncelen,
+                                        const uint8_t *aad, size_t aadlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_decrypt_cb` is a wrapper function around
+ * `ngtcp2_crypto_decrypt`.  It can be directly passed to
+ * :member:`ngtcp2_callbacks.decrypt` field.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_TLS_DECRYPT`.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_decrypt_cb(uint8_t *dest, const ngtcp2_crypto_aead *aead,
+                         const ngtcp2_crypto_aead_ctx *aead_ctx,
+                         const uint8_t *ciphertext, size_t ciphertextlen,
+                         const uint8_t *nonce, size_t noncelen,
+                         const uint8_t *aad, size_t aadlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hp_mask` generates mask which is used in packet
+ * header encryption.  The mask is written to the buffer pointed by
+ * |dest|.  The sample is passed as |sample| which is
+ * :macro:`NGTCP2_HP_SAMPLELEN` bytes long.  The length of mask must
+ * be at least :macro:`NGTCP2_HP_MASKLEN`.  The library only uses the
+ * first :macro:`NGTCP2_HP_MASKLEN` bytes of the produced mask.  The
+ * buffer pointed by |dest| must have at least
+ * :macro:`NGTCP2_HP_SAMPLELEN` bytes available.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_hp_mask(uint8_t *dest,
+                                        const ngtcp2_crypto_cipher *hp,
+                                        const ngtcp2_crypto_cipher_ctx *hp_ctx,
+                                        const uint8_t *sample);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_hp_mask_cb` is a wrapper function around
+ * `ngtcp2_crypto_hp_mask`.  It can be directly passed to
+ * :member:`ngtcp2_callbacks.hp_mask` field.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_hp_mask_cb(uint8_t *dest, const ngtcp2_crypto_cipher *hp,
+                         const ngtcp2_crypto_cipher_ctx *hp_ctx,
+                         const uint8_t *sample);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_derive_and_install_rx_key` derives the rx keys from
+ * |secret| and installs new keys to |conn|.
+ *
+ * If |key| is not NULL, the derived packet protection key for
+ * decryption is written to the buffer pointed by |key|.  If |iv| is
+ * not NULL, the derived packet protection IV for decryption is
+ * written to the buffer pointed by |iv|.  If |hp| is not NULL, the
+ * derived header protection key for decryption is written to the
+ * buffer pointed by |hp|.
+ *
+ * |secretlen| specifies the length of |secret|.
+ *
+ * The length of packet protection key and header protection key is
+ * `ngtcp2_crypto_aead_keylen(ctx->aead) <ngtcp2_crypto_aead_keylen>`,
+ * and the length of packet protection IV is
+ * `ngtcp2_crypto_packet_protection_ivlen(ctx->aead)
+ * <ngtcp2_crypto_packet_protection_ivlen>` where ctx is obtained by
+ * `ngtcp2_crypto_ctx_tls` (or `ngtcp2_crypto_ctx_tls_early` if
+ * |level| == :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`).
+ *
+ * In the first call of this function, it calls
+ * `ngtcp2_conn_set_crypto_ctx` (or `ngtcp2_conn_set_early_crypto_ctx`
+ * if |level| ==
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`) to set
+ * negotiated AEAD and message digest algorithm.  After the successful
+ * call of this function, application can use
+ * `ngtcp2_conn_get_crypto_ctx` (or `ngtcp2_conn_get_early_crypto_ctx`
+ * if |level| ==
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`) to get
+ * :type:`ngtcp2_crypto_ctx`.
+ *
+ * If |conn| is initialized as client, and |level| is
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_APPLICATION`, this
+ * function retrieves a remote QUIC transport parameters extension
+ * from an object obtained by `ngtcp2_conn_get_tls_native_handle` and
+ * sets it to |conn| by calling
+ * `ngtcp2_conn_decode_remote_transport_params`.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_derive_and_install_rx_key(
+    ngtcp2_conn *conn, uint8_t *key, uint8_t *iv, uint8_t *hp,
+    ngtcp2_crypto_level level, const uint8_t *secret, size_t secretlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_derive_and_install_tx_key` derives the tx keys from
+ * |secret| and installs new keys to |conn|.
+ *
+ * If |key| is not NULL, the derived packet protection key for
+ * encryption is written to the buffer pointed by |key|.  If |iv| is
+ * not NULL, the derived packet protection IV for encryption is
+ * written to the buffer pointed by |iv|.  If |hp| is not NULL, the
+ * derived header protection key for encryption is written to the
+ * buffer pointed by |hp|.
+ *
+ * |secretlen| specifies the length of |secret|.
+ *
+ * The length of packet protection key and header protection key is
+ * `ngtcp2_crypto_aead_keylen(ctx->aead) <ngtcp2_crypto_aead_keylen>`,
+ * and the length of packet protection IV is
+ * `ngtcp2_crypto_packet_protection_ivlen(ctx->aead)
+ * <ngtcp2_crypto_packet_protection_ivlen>` where ctx is obtained by
+ * `ngtcp2_crypto_ctx_tls` (or `ngtcp2_crypto_ctx_tls_early` if
+ * |level| == :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`).
+ *
+ * In the first call of this function, it calls
+ * `ngtcp2_conn_set_crypto_ctx` (or `ngtcp2_conn_set_early_crypto_ctx`
+ * if |level| ==
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`) to set
+ * negotiated AEAD and message digest algorithm.  After the successful
+ * call of this function, application can use
+ * `ngtcp2_conn_get_crypto_ctx` (or `ngtcp2_conn_get_early_crypto_ctx`
+ * if |level| ==
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_EARLY`) to get
+ * :type:`ngtcp2_crypto_ctx`.
+ *
+ * If |conn| is initialized as server, and |level| is
+ * :enum:`ngtcp2_crypto_level.NGTCP2_CRYPTO_LEVEL_APPLICATION`, this
+ * function retrieves a remote QUIC transport parameters extension
+ * from an object obtained by `ngtcp2_conn_get_tls_native_handle` and
+ * sets it to |conn| by calling
+ * `ngtcp2_conn_decode_remote_transport_params`.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_derive_and_install_tx_key(
+    ngtcp2_conn *conn, uint8_t *key, uint8_t *iv, uint8_t *hp,
+    ngtcp2_crypto_level level, const uint8_t *secret, size_t secretlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_update_key` updates traffic keying materials.
+ *
+ * The new traffic secret for decryption is written to the buffer
+ * pointed by |rx_secret|.  The length of secret is |secretlen| bytes,
+ * and |rx_secret| must point to the buffer which has enough capacity.
+ *
+ * The new traffic secret for encryption is written to the buffer
+ * pointed by |tx_secret|.  The length of secret is |secretlen| bytes,
+ * and |tx_secret| must point to the buffer which has enough capacity.
+ *
+ * The derived packet protection key for decryption is written to the
+ * buffer pointed by |rx_key|.  The derived packet protection IV for
+ * decryption is written to the buffer pointed by |rx_iv|.
+ * |rx_aead_ctx| must be constructed with |rx_key|.
+ *
+ * The derived packet protection key for encryption is written to the
+ * buffer pointed by |tx_key|.  The derived packet protection IV for
+ * encryption is written to the buffer pointed by |tx_iv|.
+ * |tx_aead_ctx| must be constructed with |rx_key|.
+ *
+ * |current_rx_secret| and |current_tx_secret| are the current traffic
+ * secrets for decryption and encryption.  |secretlen| specifies the
+ * length of |rx_secret| and |tx_secret|.
+ *
+ * The length of packet protection key and header protection key is
+ * `ngtcp2_crypto_aead_keylen(ctx->aead) <ngtcp2_crypto_aead_keylen>`,
+ * and the length of packet protection IV is
+ * `ngtcp2_crypto_packet_protection_ivlen(ctx->aead)
+ * <ngtcp2_crypto_packet_protection_ivlen>` where ctx is obtained by
+ * `ngtcp2_crypto_ctx_tls`.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_update_key(
+    ngtcp2_conn *conn, uint8_t *rx_secret, uint8_t *tx_secret,
+    ngtcp2_crypto_aead_ctx *rx_aead_ctx, uint8_t *rx_key, uint8_t *rx_iv,
+    ngtcp2_crypto_aead_ctx *tx_aead_ctx, uint8_t *tx_key, uint8_t *tx_iv,
+    const uint8_t *current_rx_secret, const uint8_t *current_tx_secret,
+    size_t secretlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_update_key_cb` is a wrapper function around
+ * `ngtcp2_crypto_update_key`.  It can be directly passed to
+ * :member:`ngtcp2_callbacks.update_key` field.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_update_key_cb(
+    ngtcp2_conn *conn, uint8_t *rx_secret, uint8_t *tx_secret,
+    ngtcp2_crypto_aead_ctx *rx_aead_ctx, uint8_t *rx_iv,
+    ngtcp2_crypto_aead_ctx *tx_aead_ctx, uint8_t *tx_iv,
+    const uint8_t *current_rx_secret, const uint8_t *current_tx_secret,
+    size_t secretlen, void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_client_initial_cb` installs initial secrets and
+ * encryption keys and sets QUIC transport parameters.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.client_initial` field.  It is only used
+ * by client.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_client_initial_cb(ngtcp2_conn *conn,
+                                                  void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_recv_retry_cb` re-installs initial secrets in
+ * response to incoming Retry packet.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.recv_retry` field.  It is only used
+ * by client.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_recv_retry_cb(ngtcp2_conn *conn,
+                                              const ngtcp2_pkt_hd *hd,
+                                              void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_recv_client_initial_cb` installs initial secrets in
+ * response to an incoming Initial packet from client, and sets QUIC
+ * transport parameters.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.recv_client_initial` field.  It is
+ * only used by server.
+ *
+ * This function returns 0 if it succeeds, or
+ * :macro:`NGTCP2_ERR_CALLBACK_FAILURE`.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_recv_client_initial_cb(ngtcp2_conn *conn,
+                                                       const ngtcp2_cid *dcid,
+                                                       void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_read_write_crypto_data` reads CRYPTO data |data| of
+ * length |datalen| in encryption level |crypto_level| and may feed
+ * outgoing CRYPTO data to |conn|.  This function can drive handshake.
+ * This function can be also used after handshake completes.  It is
+ * allowed to call this function with |datalen| == 0.  In this case,
+ * no additional read operation is done.
+ *
+ * This function returns 0 if it succeeds, or a negative error code.
+ * The generic error code is -1 if a specific error code is not
+ * suitable.  The error codes less than -10000 are specific to
+ * underlying TLS implementation.  For OpenSSL, the error codes are
+ * defined in *ngtcp2_crypto_openssl.h*.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_read_write_crypto_data(ngtcp2_conn *conn,
+                                     ngtcp2_crypto_level crypto_level,
+                                     const uint8_t *data, size_t datalen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_recv_crypto_data_cb` is a wrapper function around
+ * `ngtcp2_crypto_read_write_crypto_data`.  It can be directly passed
+ * to :member:`ngtcp2_callbacks.recv_crypto_data` field.
+ *
+ * If this function is used, the TLS implementation specific error
+ * codes described in `ngtcp2_crypto_read_write_crypto_data` are
+ * treated as if it returns -1.  Do not use this function if an
+ * application wishes to use the TLS implementation specific error
+ * codes.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_recv_crypto_data_cb(
+    ngtcp2_conn *conn, ngtcp2_crypto_level crypto_level, uint64_t offset,
+    const uint8_t *data, size_t datalen, void *user_data);
+
+/**
+ * @function
+ *
+ *  `ngtcp2_crypto_generate_stateless_reset_token` generates a
+ *  stateless reset token using HKDF extraction using the given |cid|
+ *  and static key |secret| as input.  The token will be written to
+ *  the buffer pointed by |token| and it must have a capacity of at
+ *  least :macro:`NGTCP2_STATELESS_RESET_TOKENLEN` bytes.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_generate_stateless_reset_token(
+    uint8_t *token, const uint8_t *secret, size_t secretlen,
+    const ngtcp2_cid *cid);
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_TOKEN_RAND_DATALEN` is the length of random
+ * data added to a token generated by
+ * `ngtcp2_crypto_generate_retry_token` or
+ * `ngtcp2_crypto_generate_regular_token`.
+ */
+#define NGTCP2_CRYPTO_TOKEN_RAND_DATALEN 32
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_TOKEN_MAGIC_RETRY` is the magic byte for
+ * Retry token generated by `ngtcp2_crypto_generate_retry_token`.
+ */
+#define NGTCP2_CRYPTO_TOKEN_MAGIC_RETRY 0xb6
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_TOKEN_MAGIC_REGULAR` is the magic byte for a
+ * token generated by `ngtcp2_crypto_generate_regular_token`.
+ */
+#define NGTCP2_CRYPTO_TOKEN_MAGIC_REGULAR 0x36
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_MAX_RETRY_TOKENLEN` is the maximum length of
+ * a token generated by `ngtcp2_crypto_generate_retry_token`.
+ */
+#define NGTCP2_CRYPTO_MAX_RETRY_TOKENLEN                                       \
+  (/* magic = */ 1 + /* cid len = */ 1 + NGTCP2_MAX_CIDLEN +                   \
+   sizeof(ngtcp2_tstamp) + /* aead tag = */ 16 +                               \
+   NGTCP2_CRYPTO_TOKEN_RAND_DATALEN)
+
+/**
+ * @macro
+ *
+ * :macro:`NGTCP2_CRYPTO_MAX_REGULAR_TOKENLEN` is the maximum length
+ *  of a token generated by `ngtcp2_crypto_generate_regular_token`.
+ */
+#define NGTCP2_CRYPTO_MAX_REGULAR_TOKENLEN                                     \
+  (/* magic = */ 1 + sizeof(ngtcp2_tstamp) + /* aead tag = */ 16 +             \
+   NGTCP2_CRYPTO_TOKEN_RAND_DATALEN)
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_generate_retry_token` generates a token in the
+ * buffer pointed by |token| that is sent with Retry packet.  The
+ * buffer pointed by |token| must have at least
+ * :macro:`NGTCP2_CRYPTO_MAX_RETRY_TOKENLEN` bytes long.  The
+ * successfully generated token starts with
+ * :macro:`NGTCP2_CRYPTO_TOKEN_MAGIC_RETRY`.  |secret| of length
+ * |secretlen| is an initial keying material to generate keys to
+ * encrypt the token.  |version| is QUIC version.  |remote_addr| of
+ * length |remote_addrlen| is an address of client.  |retry_scid| is a
+ * Source Connection ID chosen by server and set in Retry packet.
+ * |odcid| is a Destination Connection ID in Initial packet sent by
+ * client.  |ts| is the timestamp when the token is generated.
+ *
+ * This function returns the length of generated token if it succeeds,
+ * or -1.
+ */
+NGTCP2_EXTERN ngtcp2_ssize ngtcp2_crypto_generate_retry_token(
+    uint8_t *token, const uint8_t *secret, size_t secretlen, uint32_t version,
+    const ngtcp2_sockaddr *remote_addr, ngtcp2_socklen remote_addrlen,
+    const ngtcp2_cid *retry_scid, const ngtcp2_cid *odcid, ngtcp2_tstamp ts);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_verify_retry_token` verifies Retry token stored in
+ * the buffer pointed by |token| of length |tokenlen|.  |secret| of
+ * length |secretlen| is an initial keying material to generate keys
+ * to decrypt the token.  |version| is QUIC version of the Initial
+ * packet that contains this token.  |remote_addr| of length
+ * |remote_addrlen| is an address of client.  |dcid| is a Destination
+ * Connection ID in Initial packet sent by client.  |timeout| is the
+ * period during which the token is valid.  |ts| is the current
+ * timestamp.  When validation succeeds, the extracted Destination
+ * Connection ID (which is the Destination Connection ID in Initial
+ * packet sent by client that triggered Retry packet) is stored to the
+ * buffer pointed by |odcid|.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_verify_retry_token(
+    ngtcp2_cid *odcid, const uint8_t *token, size_t tokenlen,
+    const uint8_t *secret, size_t secretlen, uint32_t version,
+    const ngtcp2_sockaddr *remote_addr, ngtcp2_socklen remote_addrlen,
+    const ngtcp2_cid *dcid, ngtcp2_duration timeout, ngtcp2_tstamp ts);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_generate_regular_token` generates a token in the
+ * buffer pointed by |token| that is sent with NEW_TOKEN frame.  The
+ * buffer pointed by |token| must have at least
+ * :macro:`NGTCP2_CRYPTO_MAX_REGULAR_TOKENLEN` bytes long.  The
+ * successfully generated token starts with
+ * :macro:`NGTCP2_CRYPTO_TOKEN_MAGIC_REGULAR`.  |secret| of length
+ * |secretlen| is an initial keying material to generate keys to
+ * encrypt the token.  |remote_addr| of length |remote_addrlen| is an
+ * address of client.  |ts| is the timestamp when the token is
+ * generated.
+ *
+ * This function returns the length of generated token if it succeeds,
+ * or -1.
+ */
+NGTCP2_EXTERN ngtcp2_ssize ngtcp2_crypto_generate_regular_token(
+    uint8_t *token, const uint8_t *secret, size_t secretlen,
+    const ngtcp2_sockaddr *remote_addr, ngtcp2_socklen remote_addrlen,
+    ngtcp2_tstamp ts);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_verify_regular_token` verifies a regular token
+ * stored in the buffer pointed by |token| of length |tokenlen|.
+ * |secret| of length |secretlen| is an initial keying material to
+ * generate keys to decrypt the token.  |remote_addr| of length
+ * |remote_addrlen| is an address of client.  |timeout| is the period
+ * during which the token is valid.  |ts| is the current timestamp.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_verify_regular_token(
+    const uint8_t *token, size_t tokenlen, const uint8_t *secret,
+    size_t secretlen, const ngtcp2_sockaddr *remote_addr,
+    ngtcp2_socklen remote_addrlen, ngtcp2_duration timeout, ngtcp2_tstamp ts);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_write_connection_close` writes Initial packet
+ * containing CONNECTION_CLOSE with the given |error_code| and the
+ * optional |reason| of length |reasonlen| to the buffer pointed by
+ * |dest| of length |destlen|.  This function is designed for server
+ * to close connection without committing the state when validating
+ * Retry token fails.  This function must not be used by client.  The
+ * |dcid| must be the Source Connection ID in Initial packet from
+ * client.  The |scid| must be the Destination Connection ID in
+ * Initial packet from client.  |scid| is used to derive initial
+ * keying materials.
+ *
+ * This function wraps around `ngtcp2_pkt_write_connection_close` for
+ * easier use.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN ngtcp2_ssize ngtcp2_crypto_write_connection_close(
+    uint8_t *dest, size_t destlen, uint32_t version, const ngtcp2_cid *dcid,
+    const ngtcp2_cid *scid, uint64_t error_code, const uint8_t *reason,
+    size_t reasonlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_write_retry` writes Retry packet to the buffer
+ * pointed by |dest| of length |destlen|.  |odcid| specifies Original
+ * Destination Connection ID.  |token| specifies Retry Token, and
+ * |tokenlen| specifies its length.
+ *
+ * This function wraps around `ngtcp2_pkt_write_retry` for easier use.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN ngtcp2_ssize ngtcp2_crypto_write_retry(
+    uint8_t *dest, size_t destlen, uint32_t version, const ngtcp2_cid *dcid,
+    const ngtcp2_cid *scid, const ngtcp2_cid *odcid, const uint8_t *token,
+    size_t tokenlen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_aead_ctx_encrypt_init` initializes |aead_ctx| with
+ * new AEAD cipher context object for encryption which is constructed
+ * to use |key| as encryption key.  |aead| specifies AEAD cipher to
+ * use.  |noncelen| is the length of nonce.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_aead_ctx_encrypt_init(ngtcp2_crypto_aead_ctx *aead_ctx,
+                                    const ngtcp2_crypto_aead *aead,
+                                    const uint8_t *key, size_t noncelen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_aead_ctx_decrypt_init` initializes |aead_ctx| with
+ * new AEAD cipher context object for decryption which is constructed
+ * to use |key| as encryption key.  |aead| specifies AEAD cipher to
+ * use.  |noncelen| is the length of nonce.
+ *
+ * This function returns 0 if it succeeds, or -1.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_aead_ctx_decrypt_init(ngtcp2_crypto_aead_ctx *aead_ctx,
+                                    const ngtcp2_crypto_aead *aead,
+                                    const uint8_t *key, size_t noncelen);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_aead_ctx_free` frees up resources used by
+ * |aead_ctx|.  This function does not free the memory pointed by
+ * |aead_ctx| itself.
+ */
+NGTCP2_EXTERN void
+ngtcp2_crypto_aead_ctx_free(ngtcp2_crypto_aead_ctx *aead_ctx);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_delete_crypto_aead_ctx_cb` deletes the given |aead_ctx|.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.delete_crypto_aead_ctx` field.
+ */
+NGTCP2_EXTERN void ngtcp2_crypto_delete_crypto_aead_ctx_cb(
+    ngtcp2_conn *conn, ngtcp2_crypto_aead_ctx *aead_ctx, void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_delete_crypto_cipher_ctx_cb` deletes the given
+ * |cipher_ctx|.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.delete_crypto_cipher_ctx` field.
+ */
+NGTCP2_EXTERN void ngtcp2_crypto_delete_crypto_cipher_ctx_cb(
+    ngtcp2_conn *conn, ngtcp2_crypto_cipher_ctx *cipher_ctx, void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_get_path_challenge_data_cb` writes unpredictable
+ * sequence of :macro:`NGTCP2_PATH_CHALLENGE_DATALEN` bytes to |data|
+ * which is sent with PATH_CHALLENGE frame.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.get_path_challenge_data` field.
+ */
+NGTCP2_EXTERN int ngtcp2_crypto_get_path_challenge_data_cb(ngtcp2_conn *conn,
+                                                           uint8_t *data,
+                                                           void *user_data);
+
+/**
+ * @function
+ *
+ * `ngtcp2_crypto_version_negotiation_cb` installs Initial keys for
+ * |version| which is negotiated or being negotiated.  |client_dcid|
+ * is the destination connection ID in first Initial packet of client.
+ *
+ * This function can be directly passed to
+ * :member:`ngtcp2_callbacks.version_negotiation` field.
+ */
+NGTCP2_EXTERN int
+ngtcp2_crypto_version_negotiation_cb(ngtcp2_conn *conn, uint32_t version,
+                                     const ngtcp2_cid *client_dcid,
+                                     void *user_data);
+
+typedef struct ngtcp2_crypto_conn_ref ngtcp2_crypto_conn_ref;
+
+/**
+ * @functypedef
+ *
+ * :type:`ngtcp2_crypto_get_conn` is a callback function to get a
+ * pointer to :type:`ngtcp2_conn` from |conn_ref|.  The implementation
+ * must return non-NULL :type:`ngtcp2_conn` object.
+ */
+typedef ngtcp2_conn *(*ngtcp2_crypto_get_conn)(
+    ngtcp2_crypto_conn_ref *conn_ref);
+
+/**
+ * @struct
+ *
+ * :type:`ngtcp2_crypto_conn_ref` is a structure to get a pointer to
+ * :type:`ngtcp2_conn`.  It is meant to be set to TLS native handle as
+ * an application specific data (e.g. SSL_set_app_data in OpenSSL).
+ */
+typedef struct ngtcp2_crypto_conn_ref {
+  /**
+   * :member:`get_conn` is a callback function to get a pointer to
+   * :type:`ngtcp2_conn` object.
+   */
+  ngtcp2_crypto_get_conn get_conn;
+  /**
+   * :member:`user_data` is a pointer to arbitrary user data.
+   */
+  void *user_data;
+} ngtcp2_crypto_conn_ref;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NGTCP2_CRYPTO_H */