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API Reference

#./fio-stl/190 tls13.h

60 public symbols.

#Macros

#FIO_TLS13_SHA256_HASH_LEN

c
#define FIO_TLS13_SHA256_HASH_LEN 32

SHA-256 hash length (32 bytes).

Symbol type: macro

#FIO_TLS13_SHA384_HASH_LEN

c
#define FIO_TLS13_SHA384_HASH_LEN 48

SHA-384 hash length (48 bytes).

Symbol type: macro

#FIO_TLS13_MAX_HASH_LEN

c
#define FIO_TLS13_MAX_HASH_LEN 48

Maximum hash length supported.

Symbol type: macro

#FIO_TLS13_AES128_KEY_LEN

c
#define FIO_TLS13_AES128_KEY_LEN 16

AES-128-GCM key length.

Symbol type: macro

#FIO_TLS13_AES256_KEY_LEN

c
#define FIO_TLS13_AES256_KEY_LEN 32

AES-256-GCM key length.

Symbol type: macro

#FIO_TLS13_CHACHA_KEY_LEN

c
#define FIO_TLS13_CHACHA_KEY_LEN 32

ChaCha20-Poly1305 key length.

Symbol type: macro

#FIO_TLS13_IV_LEN

c
#define FIO_TLS13_IV_LEN 12

IV length for all AEAD ciphers.

Symbol type: macro

#FIO_TLS13_RECORD_HEADER_LEN

c
#define FIO_TLS13_RECORD_HEADER_LEN 5

TLS record header length (5 bytes)

Symbol type: macro

#FIO_TLS13_MAX_PLAINTEXT_LEN

c
#define FIO_TLS13_MAX_PLAINTEXT_LEN 16384

Maximum plaintext fragment length (2^14 = 16384 bytes)

Symbol type: macro

#FIO_TLS13_MAX_CIPHERTEXT_LEN

c
#define FIO_TLS13_MAX_CIPHERTEXT_LEN (16384 + 256)

Maximum ciphertext length (plaintext + padding + tag)

Symbol type: macro

#FIO_TLS13_TAG_LEN

c
#define FIO_TLS13_TAG_LEN 16

AEAD authentication tag length (16 bytes for all TLS 1.3 ciphers)

Symbol type: macro

#FIO_TLS13_LEGACY_VERSION_MAJOR

c
#define FIO_TLS13_LEGACY_VERSION_MAJOR 0x03

Legacy TLS version bytes (0x0303 = TLS 1.2)

Symbol type: macro

#FIO_TLS13_LEGACY_VERSION_MINOR

c
#define FIO_TLS13_LEGACY_VERSION_MINOR 0x03

Symbol type: macro

#FIO_TLS13_VERSION_TLS12

c
#define FIO_TLS13_VERSION_TLS12 0x0303

TLS 1.3 Protocol Version Constants

Symbol type: macro

#FIO_TLS13_VERSION_TLS13

c
#define FIO_TLS13_VERSION_TLS13 0x0304

Symbol type: macro

#FIO_TLS13_HRR_RANDOM

c
#define FIO_TLS13_HRR_RANDOM   \
  "\xCF\x21\xAD\x74\xE5\x9A\x61\x11\xBE\x1D\x8C\x02\x1E\x65\xB8\x91"   \
  "\xC2\xA2\x11\x16\x7A\xBB\x8C\x5E\x07\x9E\x09\xE2\xC8\xA8\x33\x9C"

HelloRetryRequest magic random value (RFC 8446 Section 4.1.3)

Symbol type: macro

#Types

#fio_tls13_content_type_e

c
typedef enum {
FIO_TLS13_CONTENT_INVALID = 0,
FIO_TLS13_CONTENT_CHANGE_CIPHER_SPEC = 20, /* Legacy, ignored in TLS 1.3 */
FIO_TLS13_CONTENT_ALERT = 21,
FIO_TLS13_CONTENT_HANDSHAKE = 22,
FIO_TLS13_CONTENT_APPLICATION_DATA = 23,
} fio_tls13_content_type_e

TLS 1.3 content types

Symbol type: type

#fio_tls13_handshake_type_e

c
typedef enum {
FIO_TLS13_HS_CLIENT_HELLO = 1,
FIO_TLS13_HS_SERVER_HELLO = 2,
FIO_TLS13_HS_NEW_SESSION_TICKET = 4,
FIO_TLS13_HS_END_OF_EARLY_DATA = 5,
FIO_TLS13_HS_ENCRYPTED_EXTENSIONS = 8,
FIO_TLS13_HS_CERTIFICATE = 11,
FIO_TLS13_HS_CERTIFICATE_REQUEST = 13,
FIO_TLS13_HS_CERTIFICATE_VERIFY = 15,
FIO_TLS13_HS_FINISHED = 20,
FIO_TLS13_HS_KEY_UPDATE = 24,
FIO_TLS13_HS_MESSAGE_HASH = 254,
} fio_tls13_handshake_type_e

TLS 1.3 Handshake Message Types

Symbol type: type

#fio_tls13_key_update_request_e

c
typedef enum {
FIO_TLS13_KEY_UPDATE_NOT_REQUESTED = 0,
FIO_TLS13_KEY_UPDATE_REQUESTED = 1,
} fio_tls13_key_update_request_e

TLS 1.3 KeyUpdate Request Types (RFC 8446 Section 4.6.3)

Symbol type: type

#fio_tls13_extension_type_e

c
typedef enum {
FIO_TLS13_EXT_SERVER_NAME = 0, /* SNI */
FIO_TLS13_EXT_SUPPORTED_GROUPS = 10, /* Key exchange groups */
FIO_TLS13_EXT_SIGNATURE_ALGORITHMS = 13, /* Signature schemes */
FIO_TLS13_EXT_ALPN = 16, /* Application-Layer Protocol Negotiation */
FIO_TLS13_EXT_SUPPORTED_VERSIONS = 43, /* TLS version negotiation */
FIO_TLS13_EXT_COOKIE = 44, /* Cookie for HRR (RFC 8446 4.2.2) */
FIO_TLS13_EXT_CERTIFICATE_AUTHORITIES =
47, /* Acceptable CAs (RFC 8446 4.2.4) */
FIO_TLS13_EXT_SIGNATURE_ALGORITHMS_CERT = 50, /* Cert chain sig algs */
FIO_TLS13_EXT_KEY_SHARE = 51, /* ECDHE key shares */
} fio_tls13_extension_type_e

TLS 1.3 Extension Types (RFC 8446 Section 4.2)

Symbol type: type

#fio_tls13_cipher_suite_e

c
typedef enum {
FIO_TLS13_CIPHER_SUITE_AES_128_GCM_SHA256 = 0x1301,
FIO_TLS13_CIPHER_SUITE_AES_256_GCM_SHA384 = 0x1302,
FIO_TLS13_CIPHER_SUITE_CHACHA20_POLY1305_SHA256 = 0x1303,
} fio_tls13_cipher_suite_e

TLS 1.3 Cipher Suites (RFC 8446 Section B.4)

Symbol type: type

#fio_tls13_named_group_e

c
typedef enum {
FIO_TLS13_GROUP_SECP256R1 = 23, /* P-256 */
FIO_TLS13_GROUP_SECP384R1 = 24, /* P-384 */
FIO_TLS13_GROUP_X25519 = 29, /* Curve25519 */
FIO_TLS13_GROUP_X25519MLKEM768 =
0x11ec, /* X25519 + ML-KEM-768 hybrid (PQC) */
} fio_tls13_named_group_e

TLS 1.3 Named Groups (RFC 8446 Section 4.2.7, draft-ietf-tls-hybrid-design)

Symbol type: type

#fio_tls13_signature_algo_e

c
typedef enum {
FIO_TLS13_SIGNATURE_RSA_PKCS1_SHA256 = 0x0401,
FIO_TLS13_SIGNATURE_RSA_PKCS1_SHA384 = 0x0501,
FIO_TLS13_SIGNATURE_RSA_PKCS1_SHA512 = 0x0601,
FIO_TLS13_SIGNATURE_ECDSA_SECP256R1_SHA256 = 0x0403,
FIO_TLS13_SIGNATURE_ECDSA_SECP384R1_SHA384 = 0x0503,
FIO_TLS13_SIGNATURE_RSA_PSS_RSAE_SHA256 = 0x0804,
FIO_TLS13_SIGNATURE_RSA_PSS_RSAE_SHA384 = 0x0805,
FIO_TLS13_SIGNATURE_ED25519 = 0x0807,
} fio_tls13_signature_algo_e

TLS 1.3 Signature Algorithms (RFC 8446 Section 4.2.3)

Symbol type: type

#fio_tls13_server_hello_s

c
typedef struct {
uint8_t random[32]; /* Server random */
uint16_t cipher_suite; /* Selected cipher suite */
uint8_t
key_share[1120]; /* Server's key share (max size for X25519MLKEM768) */
uint16_t key_share_len; /* Length of key share */
uint16_t key_share_group; /* Selected group */
int is_hello_retry_request; /* 1 if HRR */
} fio_tls13_server_hello_s

Parsed ServerHello message

Symbol type: type

#fio_tls13_encrypted_extensions_s

c
typedef struct {
int has_server_name; /* Server acknowledged SNI */
char alpn_selected[256]; /* Selected ALPN protocol (null-terminated) */
size_t alpn_selected_len; /* Length of selected ALPN protocol */
} fio_tls13_encrypted_extensions_s

Parsed EncryptedExtensions message

Symbol type: type

#fio_tls13_certificate_s

c
typedef struct {
fio_ubuf_info_s cert; /* First certificate (view into message data) */
} fio_tls13_certificate_s

Parsed Certificate message (minimal - first cert only)

Symbol type: type

#fio_tls13_certificate_verify_s

c
typedef struct {
fio_ubuf_info_s signature; /* Signature (view into message data) */
uint16_t signature_algo;
} fio_tls13_certificate_verify_s

Parsed CertificateVerify message

Symbol type: type

#fio_tls13_certificate_request_s

c
typedef struct {
fio_ubuf_info_s authorities; /* Raw CA DNs data (view into message) */
size_t context_len; /* Context length (0-255) */
size_t algo_count; /* Number of signature algorithms */
size_t cert_algos_count; /* Number of cert sig algos */
uint16_t algos[16]; /* Required signature algorithms */
uint16_t cert_algos[16]; /* Cert chain sig algos (optional) */
uint8_t context[255]; /* Opaque context */
} fio_tls13_certificate_request_s

Parsed CertificateRequest message (RFC 8446 Section 4.3.2)

Symbol type: type

#fio_tls13_cipher_type_e

c
typedef enum {
FIO_TLS13_CIPHER_AES_128_GCM = 0, /* TLS_AES_128_GCM_SHA256 */
FIO_TLS13_CIPHER_AES_256_GCM = 1, /* TLS_AES_256_GCM_SHA384 */
FIO_TLS13_CIPHER_CHACHA20_POLY1305 = 2, /* TLS_CHACHA20_POLY1305_SHA256 */
} fio_tls13_cipher_type_e

Supported AEAD cipher types for TLS 1.3

Symbol type: type

#fio_tls13_plaintext_header_s

c
typedef struct {
uint8_t content_type; /* ContentType */
uint8_t legacy_version[2]; /* 0x03, 0x03 (TLS 1.2) */
uint16_t length; /* Fragment length (big-endian) */
/* Fragment follows (up to 2^14 bytes) */
} fio_tls13_plaintext_header_s

TLSPlaintext header structure (RFC 8446 Section 5.1)

Symbol type: type

#fio_tls13_ciphertext_header_s

c
typedef struct {
uint8_t opaque_type; /* Always 23 (application_data) */
uint8_t legacy_version[2]; /* 0x03, 0x03 */
uint16_t length; /* Encrypted length + tag (big-endian) */
/* Encrypted content follows */
} fio_tls13_ciphertext_header_s

TLSCiphertext header structure (RFC 8446 Section 5.2)

Symbol type: type

#fio_tls13_record_keys_s

c
typedef struct {
uint8_t key[32]; /* Write key (16 or 32 bytes depending on cipher) */
uint8_t iv[12]; /* Write IV (always 12 bytes) */
uint64_t sequence_number; /* Per-record sequence number (starts at 0) */
uint8_t key_len; /* 16 for AES-128, 32 for AES-256/ChaCha20 */
uint8_t cipher_type; /* fio_tls13_cipher_type_e */
} fio_tls13_record_keys_s

Record encryption context (per-direction keys)

Symbol type: type

#Functions

#fio_tls13_hkdf_expand_label

c
void fio_tls13_hkdf_expand_label(void *restrict out, size_t out_len, const void *restrict secret, size_t secret_len, const char *label, size_t label_len, const void *restrict context, size_t context_len, int use_sha384)

TLS 1.3 HKDF-Expand-Label function.

Derives keying material using the TLS 1.3 specific label format.

Parameters:

  • out - Output buffer for derived key material
  • out_len - Desired output length (max 255)
  • secret - The secret to expand (PRK from HKDF-Extract)
  • secret_len - Secret length (32 for SHA-256, 48 for SHA-384)
  • label - The label string (without "tls13 " prefix)
  • label_len - Label length (max 249 to fit in 255 with prefix)
  • context - Optional context (transcript hash or empty)
  • context_len - Context length (max 255)
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_secret

c
void fio_tls13_derive_secret(void *restrict out, const void *restrict secret, size_t secret_len, const char *label, size_t label_len, const void *restrict transcript_hash, size_t hash_len, int use_sha384)

TLS 1.3 Derive-Secret function.

Derives a secret from a base secret and transcript hash.

Parameters:

  • out - Output buffer (32 bytes for SHA-256, 48 for SHA-384)
  • secret - The base secret
  • secret_len - Secret length
  • label - The label string (e.g., "c hs traffic")
  • label_len - Label length
  • transcript_hash - Hash of handshake messages (or empty hash for "")
  • hash_len - Hash length (32 or 48)
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_early_secret

c
void fio_tls13_derive_early_secret(void *restrict early_secret, const void *restrict psk, size_t psk_len, int use_sha384)

Derive the Early Secret from PSK.

Early Secret = HKDF-Extract(salt=0, IKM=PSK)

Parameters:

  • early_secret - Output buffer (32 or 48 bytes)
  • psk - Pre-shared key (or NULL/zeros for no PSK)
  • psk_len - PSK length (0 if no PSK)
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_handshake_secret

c
void fio_tls13_derive_handshake_secret(void *restrict handshake_secret, const void *restrict early_secret, const void *restrict ecdhe_secret, size_t ecdhe_len, int use_sha384)

Derive the Handshake Secret from ECDHE shared secret.

Handshake Secret = HKDF-Extract( salt=Derive-Secret(Early Secret, "derived", ""), IKM=ECDHE shared secret )

Parameters:

  • handshake_secret - Output buffer (32 or 48 bytes)
  • early_secret - The early secret (from fio_tls13_derive_early_secret)
  • ecdhe_secret - The ECDHE shared secret (e.g., from X25519)
  • ecdhe_len - ECDHE secret length (32 for X25519)
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_master_secret

c
void fio_tls13_derive_master_secret(void *restrict master_secret, const void *restrict handshake_secret, int use_sha384)

Derive the Master Secret.

Master Secret = HKDF-Extract( salt=Derive-Secret(Handshake Secret, "derived", ""), IKM=0 )

Parameters:

  • master_secret - Output buffer (32 or 48 bytes)
  • handshake_secret - The handshake secret
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_traffic_keys

c
void fio_tls13_derive_traffic_keys(void *restrict key, size_t key_len, void *restrict iv, const void *restrict traffic_secret, int use_sha384)

Derive traffic keys and IV from a traffic secret.

Parameters:

  • key - Output buffer for write key
  • key_len - Key length (16 for AES-128, 32 for AES-256/ChaCha20)
  • iv - Output buffer for write IV (12 bytes)
  • traffic_secret - The traffic secret (client/server handshake/app)
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_derive_finished_key

c
void fio_tls13_derive_finished_key(void *restrict finished_key, const void *restrict traffic_secret, int use_sha384)

Derive the Finished key from a traffic secret.

finished_key = HKDF-Expand-Label(BaseKey, "finished", "", Hash.length)

Parameters:

  • finished_key - Output buffer (32 or 48 bytes)
  • traffic_secret - The handshake traffic secret
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_compute_finished

c
void fio_tls13_compute_finished(void *restrict verify_data, const void *restrict finished_key, const void *restrict transcript_hash, int use_sha384)

Compute the Finished verify_data.

verify_data = HMAC(finished_key, Transcript-Hash(Handshake Context))

Parameters:

  • verify_data - Output buffer (32 or 48 bytes)
  • finished_key - The finished key (from fio_tls13_derive_finished_key)
  • transcript_hash - Hash of handshake messages up to this point
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_update_traffic_secret

c
void fio_tls13_update_traffic_secret(void *restrict new_secret, const void *restrict current_secret, int use_sha384)

Update application traffic secret for key update.

application_traffic_secret_N+1 = HKDF-Expand-Label(application_traffic_secret_N, "traffic upd", "", Hash.length)

Parameters:

  • new_secret - Output buffer (32 or 48 bytes)
  • current_secret - Current application traffic secret
  • use_sha384 - If non-zero, use SHA-384; otherwise SHA-256

Symbol type: function

#fio_tls13_build_nonce

c
inline void fio_tls13_build_nonce(uint8_t nonce[12], const uint8_t iv[12], uint64_t seq)

Build per-record nonce by XORing sequence number with IV.

Per RFC 8446 Section 5.3:

  • Pad 64-bit sequence number to 12 bytes (big-endian, left-padded with zeros)
  • XOR with the static IV derived from traffic secret

Parameters:

  • nonce - Output buffer (must be 12 bytes)
  • iv - Static IV from key derivation (12 bytes)
  • seq - 64-bit sequence number

Symbol type: function

#fio_tls13_record_parse_header

c
const uint8_t *fio_tls13_record_parse_header( const uint8_t *data, size_t data_len, fio_tls13_content_type_e *content_type, size_t *payload_len)

Parse a TLS record header.

Parameters:

  • data - Input buffer containing record data
  • data_len - Length of input buffer
  • content_type - Output: content type from header
  • payload_len - Output: payload length from header

Returns:

  • Pointer to payload data, or NULL if incomplete/invalid

Symbol type: function

#fio_tls13_record_encrypt

c
int fio_tls13_record_encrypt(uint8_t *out, size_t out_capacity, const uint8_t *plaintext, size_t plaintext_len, fio_tls13_content_type_e content_type, fio_tls13_record_keys_s *keys)

Encrypt a TLS 1.3 record.

Per RFC 8446 Section 5.2:

  • Output format: 5-byte header + encrypted(plaintext + content_type) + tag
  • AAD is the 5-byte record header
  • Sequence number is incremented after encryption

Parameters:

  • out - Output buffer for encrypted record
  • out_capacity - Capacity of output buffer
  • plaintext - Plaintext data to encrypt
  • plaintext_len - Length of plaintext
  • content_type - Content type (appended to plaintext before encryption)
  • keys - Encryption keys (sequence number will be incremented)

Returns:

  • Total output length (header + ciphertext + tag), or -1 on error

Symbol type: function

#fio_tls13_record_decrypt

c
int fio_tls13_record_decrypt(uint8_t *out, size_t out_capacity, fio_tls13_content_type_e *content_type, const uint8_t *ciphertext, size_t ciphertext_len, fio_tls13_record_keys_s *keys)

Decrypt a TLS 1.3 record.

Per RFC 8446 Section 5.2:

  • Input includes 5-byte header
  • Decrypts and verifies AEAD tag
  • Scans backwards to find real content type (removes padding)
  • Sequence number is incremented after successful decryption

Note: decryption is performed in-place in the ciphertext buffer, so the ciphertext buffer will be modified. The output buffer only needs to hold the plaintext (not the internal content type byte).

Parameters:

  • out - Output buffer for decrypted plaintext
  • out_capacity - Capacity of output buffer (>= plaintext length)
  • content_type - Output: actual content type from inner plaintext
  • ciphertext - Input ciphertext (includes 5-byte header, modified)
  • ciphertext_len - Total length including header
  • keys - Decryption keys (sequence number will be incremented)

Returns:

  • Plaintext length (excluding padding and content type), or -1 on error

Symbol type: function

#fio_tls13_record_keys_init

c
void fio_tls13_record_keys_init(fio_tls13_record_keys_s *keys, const uint8_t *key, uint8_t key_len, const uint8_t iv[12], fio_tls13_cipher_type_e cipher_type)

Initialize record keys structure.

Parameters:

  • keys - Keys structure to initialize
  • key - Key material (16 or 32 bytes)
  • key_len - Key length (16 for AES-128, 32 for AES-256/ChaCha20)
  • iv - IV material (12 bytes)
  • cipher_type - Cipher type (fio_tls13_cipher_type_e)

Symbol type: function

#fio_tls13_record_keys_clear

c
inline void fio_tls13_record_keys_clear(fio_tls13_record_keys_s *keys)

Clear sensitive key material from memory.

Parameters:

  • keys - Keys structure to clear

Symbol type: function

#fio_tls13_parse_handshake_header

c
const uint8_t *fio_tls13_parse_handshake_header( const uint8_t *data, size_t data_len, fio_tls13_handshake_type_e *msg_type, size_t *body_len)

Parse handshake header, return message type and body pointer.

Returns pointer to message body, or NULL on error. Sets msg_type and body_len on success.

Symbol type: function

#fio_tls13_write_handshake_header

c
void fio_tls13_write_handshake_header(uint8_t *out, fio_tls13_handshake_type_e msg_type, size_t body_len)

Write handshake header (4 bytes).

Format: HandshakeType (1 byte) + uint24 length (3 bytes)

Symbol type: function

#fio_tls13_build_client_hello

c
int fio_tls13_build_client_hello(uint8_t *out, size_t out_capacity, const uint8_t random[32], const char *server_name, const uint8_t *x25519_pubkey, const uint16_t *cipher_suites, size_t cipher_suite_count)

Build a ClientHello message.

Returns: message length on success, -1 on error.

Parameters:

  • out: output buffer
  • out_capacity: size of output buffer
  • random: 32-byte client random
  • server_name: SNI hostname (NULL if not used)
  • x25519_pubkey: 32-byte X25519 public key
  • cipher_suites: array of cipher suites to offer
  • cipher_suite_count: number of cipher suites

Symbol type: function

#fio_tls13_parse_server_hello

c
int fio_tls13_parse_server_hello(fio_tls13_server_hello_s *out, const uint8_t *data, size_t data_len)

Parse ServerHello message.

Returns: 0 on success, -1 on error.

Note: data should point to the handshake body (after the 4-byte header).

Symbol type: function

#fio_tls13_parse_encrypted_extensions

c
int fio_tls13_parse_encrypted_extensions( fio_tls13_encrypted_extensions_s *out, const uint8_t *data, size_t data_len)

Parse EncryptedExtensions message.

Returns: 0 on success, -1 on error.

Symbol type: function

#fio_tls13_parse_certificate

c
int fio_tls13_parse_certificate(fio_tls13_certificate_s *out, const uint8_t *data, size_t data_len)

Parse Certificate message (extracts first certificate only).

Returns: 0 on success, -1 on error.

Symbol type: function

#fio_tls13_parse_certificate_verify

c
int fio_tls13_parse_certificate_verify( fio_tls13_certificate_verify_s *out, const uint8_t *data, size_t data_len)

Parse CertificateVerify message.

Returns: 0 on success, -1 on error.

Symbol type: function

#fio_tls13_build_finished

c
int fio_tls13_build_finished(uint8_t *out, size_t out_capacity, const uint8_t *verify_data, size_t verify_data_len)

Build Finished message.

verify_data = HMAC(finished_key, Transcript-Hash(Handshake Context))

Returns: message length on success, -1 on error.

Symbol type: function

#fio_tls13_parse_finished

c
int fio_tls13_parse_finished(const uint8_t *data, size_t data_len, const uint8_t *expected_verify_data, size_t verify_data_len)

Parse and verify Finished message.

Returns: 0 on success (MAC matches), -1 on error.

Symbol type: function

#fio_tls13_build_alert

c
inline int fio_tls13_build_alert(uint8_t *out, size_t out_capacity, uint8_t alert_level, uint8_t alert_desc)

Build an alert message (unencrypted, for use before handshake keys).

Alert format: [level:1][description:1]

Parameters:

  • out - Output buffer for alert message (2 bytes minimum)
  • out_capacity - Capacity of output buffer
  • alert_level - Alert level (1=warning, 2=fatal)
  • alert_desc - Alert description code

Returns:

  • Alert message length (2), or -1 on error

Symbol type: function

#fio_tls13_send_alert

c
int fio_tls13_send_alert(uint8_t *out, size_t out_capacity, uint8_t alert_level, uint8_t alert_desc, fio_tls13_record_keys_s *keys)

Build an encrypted alert record.

Per RFC 8446 Section 6, alerts are encrypted after handshake keys are established. In TLS 1.3, all alerts except close_notify are effectively fatal and the connection must be closed after sending.

Parameters:

  • out - Output buffer for encrypted alert record
  • out_capacity - Capacity of output buffer
  • alert_level - Alert level (1=warning, 2=fatal)
  • alert_desc - Alert description code
  • keys - Encryption keys (sequence number will be incremented)

Returns:

  • Encrypted record length, or -1 on error

Symbol type: function

#fio_tls13_send_alert_plaintext

c
int fio_tls13_send_alert_plaintext(uint8_t *out, size_t out_capacity, uint8_t alert_level, uint8_t alert_desc)

Build an unencrypted alert record (for use before encryption is enabled).

Parameters:

  • out - Output buffer for alert record
  • out_capacity - Capacity of output buffer
  • alert_level - Alert level (1=warning, 2=fatal)
  • alert_desc - Alert description code

Returns:

  • Record length (7 bytes: 5 header + 2 alert), or -1 on error

Symbol type: function

#fio_tls13_alert_name

c
inline const char *fio_tls13_alert_name(uint8_t alert_desc)

Get human-readable name for an alert description.

Parameters:

  • alert_desc - Alert description code

Returns:

  • Static string with alert name

Symbol type: function