OpenSSL-APIs¶

Note

The OpenSSL-API will be discontinued in ESP-IDF from v5.0. Please use ESP-TLS <esp_tls> instead.

The code of this API (located in openssl directory), does not contain OpenSSL itself but is intended as a wrapper for applications using the OpenSSL API. It uses mbedTLS to do the actual work, so anyone compiling openssl code needs the mbedtls library and header file.

OpenSSL APIs not mentioned in this article are not open to public for the time, also do not have the corresponding function. If user calls it directly, it will always return an error or may show cannot link at compiling time.

Chapter Introduction¶

Chapter 1. SSL Context Method Create
Chapter 2. SSL Context Function
Chapter 3. SSL Function
Chapter 4. SSL X509 Certification and Private Key Function

Chapter 1. SSL Context Method Create¶

1.1 const SSL_METHOD* SSLv3_client_method (void)

Arguments:

none

Return:

SSLV3.0 version SSL context client method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = SSLv3_client_method();

    ...
}

1.2 const SSL_METHOD* TLSv1_client_method (void)

Arguments:

none

Return:

TLSV1.0 version SSL context client method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_client_method();

    ...
}

1.3 const SSL_METHOD* TLSv1_1_client_method (void)

Arguments:

none

Return:

TLSV1.1 version SSL context client method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_1_client_method();

    ...
}

1.4 const SSL_METHOD* TLSv1_2_client_method (void)

Arguments:

none

Return:

TLSV1.2 version SSL context client method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_2_client_method();

    ...
}

1.5 const SSL_METHOD* TLS_client_method (void)

Arguments:

none

Return:

TLSV1.2 version SSL context client method point

Description:

create the default SSL context method, it's always to be TLSV1.2

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_2_client_method();

    ...
}

1.6 const SSL_METHOD* SSLv3_server_method (void)

Arguments:

none

Return:

SSLV3.0 version SSL context server method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = SSLv3_server_method();

    ...
}

1.7 const SSL_METHOD* TLSv1_server_method (void)

Arguments:

none

Return:

TLSV1.0 version SSL context server method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_server_method();

    ...
}

1.8 const SSL_METHOD* TLSv1_1_server_method (void)

Arguments:

none

Return:

TLSV1.1 version SSL context server method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_1_server_method();

    ...
}

1.9 const SSL_METHOD* TLSv1_2_server_method (void)

Arguments:

none

Return:

TLSV1.2 version SSL context server method point

Description:

create the target SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_2_server_method();

    ...
}

1.10 const SSL_METHOD* TLS_server_method (void)

Arguments:

none

Return:

TLSV1.2 version SSL context server method point

Description:

create the default SSL context method, it's always to be TLSV1.2

Example:

void example(void)
{
    const SSL_METHOD *method = TLSv1_2_server_method();

    ...
}

Chapter 2. SSL Context Function¶

2.1 SSL_CTX* SSL_CTX_new (const SSL_METHOD * method)

Arguments:

method - the SSL context method point

Return:

context point

Description:

create a SSL context

Example:

void example(void)
{
    SSL_CTX *ctx = SSL_CTX_new(SSLv3_server_method());

    ...
}

2.2 void SSL_CTX_free (SSL_CTX * ctx)

Arguments:

ctx - the SSL context point

Return:

none

Description:

free a SSL context

Example:

void example(void)
{
    SSL_CTX *ctx;

    ... ...

    SSL_CTX_free(ctx);
}

2.3 int SSL_CTX_set_ssl_version (SSL_CTX * ctx, const SSL_METHOD * meth)

Arguments:

ctx  - SSL context point
meth - SSL method point

Return:

1 : OK
0 : failed

Description:

set the SSL context version

Example:

void example(void)
{
    SSL_CTX *ctx;
    const SSL_METHOD *meth;

    ... ...

    SSL_CTX_set_ssl_version(ctx, meth);
}

2.4 const SSL_METHOD* SSL_CTX_get_ssl_method (SSL_CTX * ctx)

Arguments:

ctx - SSL context point

Return:

SSL context method

Description:

get the SSL context method

Example:

void example(void)
{
    const SSL_METHOD *method;
    SSL_CTX *ctx;

    ... ...

    method = SSL_CTX_get_ssl_method(ctx);
}

Chapter 3. SSL Function¶

3.1 SSL* SSL_new (SSL_CTX * ctx)

Arguments:

ctx - SSL context point

Return:

SSL method

Description:

create a SSL

Example:

void example(void)
{
    SSL *ssl;
    SSL_CTX *ctx;

    ... ...

    ssl = SSL_new(ctx);
}

3.2 void SSL_free (SSL * ssl)

Arguments:

ssl - SSL point

Return:

none

Description:

free SSL

Example:

void example(void)
{
    SSL *ssl;

    ... ...

    SSL_free(ssl);
}

3.3 int SSL_do_handshake (SSL * ssl)

Arguments:

ssl - SSL point

Return:

 1 : OK
 0 : failed, connect is close by remote
-1 : a error catch

Description:

perform the SSL handshake

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_do_handshake(ssl);
}

3.4 int SSL_connect (SSL * ssl)

Arguments:

ssl - SSL point

Return:

 1 : OK
 0 : failed, connect is close by remote
-1 : a error catch

Description:

connect to the remote SSL server

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_connect(ssl);
}

3.5 int SSL_accept (SSL * ssl)

Arguments:

ssl - SSL point

Return:

 1 : OK
 0 : failed, connect is close by remote
-1 : a error catch

Description:

accept the remote connection

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_accept(ssl);
}

3.6 int SSL_shutdown (SSL * ssl)

Arguments:

ssl - SSL point

Return:

 1 : OK
 0 : failed, connect is close by remote
-1 : a error catch

Description:

shutdown the connection

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_shutdown(ssl);
}

3.7 int SSL_clear (SSL * ssl)

Arguments:

ssl - SSL point

Return:

1 : OK
0 : failed

Description:

shutdown the connection

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_clear(ssl);
}

3.8 int SSL_read (SSL * ssl, void * buffer, int len)

Arguments:

ssl    - point
buffer - data buffer point
len    - data length

Return:

> 0 : OK, and return received data bytes
= 0 : no data received or connection is closed
< 0 : an error catch

Description:

read data from remote

Example:

void example(void)
{
    SSL *ssl;
    char *buf;
    int len;
    int ret;

    ... ...

    ret = SSL_read(ssl, buf, len);
}

3.9 int SSL_write (SSL * ssl, const void * buffer, int len)

Arguments:

ssl    - SSL point
buffer - data buffer point
len    - data length

Return:

> 0 : OK, and return received data bytes
= 0 : no data sent or connection is closed
< 0 : an error catch

Description:

send the data to remote

Example:

void example(void)
{
    SSL *ssl;
    char *buf;
    int len;
    int ret;

    ... ...

    ret = SSL_write(ssl, buf, len);
}

3.10 SSL_CTX *SSL_get_SSL_CTX (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL context

Description:

get SSL context of the SSL

Example:

void example(void)
{
    SSL *ssl;
    SSL_CTX *ctx;

    ... ...

    ctx = SSL_get_SSL_CTX(ssl);
}

3.11 int SSL_get_shutdown (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

shutdown mode

Description:

get SSL shutdown mode

Example:

void example(void)
{
    SSL *ssl;
    int mode;

    ... ...

    mode = SSL_get_SSL_CTX(ssl);
}

3.12 void SSL_set_shutdown (SSL * ssl, int mode)

Arguments:

ssl - SSL point

Return:

shutdown mode

Description:

set SSL shutdown mode

Example:

void example(void)
{
    SSL *ssl;
    int mode = 0;

    ... ...

    SSL_set_shutdown(ssl, mode);
}

3.13 const SSL_METHOD* SSL_get_ssl_method (SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL method

Description:

set SSL shutdown mode

Example:

void example(void)
{
    SSL *ssl;
    const SSL_METHOD *method;

    ... ...

    method = SSL_get_ssl_method(ssl);
}

3.14 int SSL_set_ssl_method (SSL * ssl, const SSL_METHOD * method)

Arguments:

ssl  - SSL point
meth - SSL method point

Return:

1 : OK
0 : failed

Description:

set the SSL method

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    const SSL_METHOD *method;

    ... ...

    ret = SSL_set_ssl_method(ssl, method);
}

3.15 int SSL_pending (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

data bytes

Description:

get received data bytes

Example:

void example(void)
{
    int ret;
    SSL *ssl;

    ... ...

    ret = SSL_pending(ssl);
}

3.16 int SSL_has_pending (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

1 : Yes
0 : No

Description:

check if data is received

Example:

void example(void)
{
    int ret;
    SSL *ssl;

    ... ...

    ret = SSL_has_pending(ssl);
}

3.17 int SSL_get_fd (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

>= 0 : socket id
 < 0 : a error catch

Description:

get the socket of the SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;

    ... ...

    ret = SSL_get_fd(ssl);
}

3.18 int SSL_get_rfd (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

>= 0 : socket id
 < 0 : a error catch

Description:

get the read only socket of the SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;

    ... ...

    ret = SSL_get_rfd(ssl);
}

3.19 int SSL_get_wfd (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

>= 0 : socket id
 < 0 : a error catch

Description:

get the write only socket of the SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;

    ... ...

    ret = SSL_get_wfd(ssl);
}

3.20 int SSL_set_fd (SSL * ssl, int fd)

Arguments:

ssl - SSL point
fd  - socket id

Return:

1 : OK
0 : failed

Description:

set socket to SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    int socket;

    ... ...

    ret = SSL_set_fd(ssl, socket);
}

3.21 int SSL_set_rfd (SSL * ssl, int fd)

Arguments:

ssl - SSL point
fd  - socket id

Return:

1 : OK
0 : failed

Description:

set read only socket to SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    int socket;

    ... ...

    ret = SSL_set_rfd(ssl, socket);
}

3.22 int SSL_set_wfd (SSL * ssl, int fd)

Arguments:

ssl - SSL point
fd  - socket id

Return:

1 : OK
0 : failed

Description:

set write only socket to SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    int socket;

    ... ...

    ret = SSL_set_wfd(ssl, socket);
}

3.23 int SSL_version (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL version

Description:

get SSL version

Example:

void example(void)
{
    int version;
    SSL *ssl;

    ... ...

    version = SSL_version(ssl);
}

3.24 const char* SSL_get_version (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL version string

Description:

get the SSL current version string

Example:

void example(void)
{
    char *version;
    SSL *ssl;

    ... ...

    version = SSL_get_version(ssl);
}

3.25 OSSL_HANDSHAKE_STATE SSL_get_state (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL state

Description:

get the SSL state

Example:

void example(void)
{
    OSSL_HANDSHAKE_STATE state;
    SSL *ssl;

    ... ...

    state = SSL_get_state(ssl);
}

3.26 const char* SSL_alert_desc_string (int value)

Arguments:

value - SSL description

Return:

alert value string

Description:

get alert description string

Example:

void example(void)
{
    int val;
    char *str;

    ... ...

    str = SSL_alert_desc_string(val);
}

3.27 const char* SSL_alert_desc_string_long (int value)

Arguments:

value - SSL description

Return:

alert value long string

Description:

get alert description long string

Example:

void example(void)
{
    int val;
    char *str;

    ... ...

    str = SSL_alert_desc_string_long(val);
}

3.28 const char* SSL_alert_type_string (int value)

Arguments:

value - SSL type description

Return:

alert type string

Description:

get alert type string

Example:

void example(void)
{
    int val;
    char *str;

    ... ...

    str = SSL_alert_type_string(val);
}

3.29 const char* SSL_alert_type_string_long (int value)

Arguments:

value - SSL type description

Return:

alert type long string

Description:

get alert type long string

Example:

void example(void)
{
    int val;
    char *str;

    ... ...

    str = SSL_alert_type_string_long(val);
}

3.30 const char* SSL_rstate_string (SSL * ssl)

Arguments:

ssl - SSL point

Return:

state string

Description:

get the state string where SSL is reading

Example:

void example(void)
{
    SSL *ssl;
    char *str;

    ... ...

    str = SSL_rstate_string(ssl);
}

3.31 const char* SSL_rstate_string_long (SSL * ssl)

Arguments:

ssl - SSL point

Return:

state long string

Description:

get the state long string where SSL is reading

Example:

void example(void)
{
    SSL *ssl;
    char *str;

    ... ...

    str = SSL_rstate_string_long(ssl);
}

3.32 const char* SSL_state_string (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

state string

Description:

get the state string

Example:

void example(void)
{
    SSL *ssl;
    const char *str;

    ... ...

    str = SSL_state_string(ssl);
}

3.33 char* SSL_state_string_long (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

state long string

Description:

get the state long string

Example:

void example(void)
{
    SSL *ssl;
    char *str;

    ... ...

    str = SSL_state_string(ssl);
}

3.34 int SSL_get_error (const SSL * ssl, int ret_code)

Arguments:

ssl      - SSL point
ret_code - SSL return code

Return:

SSL error number

Description:

get SSL error code

Example:

void example(void)
{
    SSL *ssl;
    int ret;
    int err;

    ... ...

    err = SSL_get_error(ssl, ret);
}

3.35 int SSL_want (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

specifical statement

Description:

get the SSL specifical statement

Example:

void example(void)
{
    SSL *ssl;
    int state;

    ... ...

    state = SSL_want(ssl);
}

3.36 int SSL_want_nothing (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

0 : false
1 : true

Description:

check if SSL want nothing

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_want(ssl);
}

3.37 int SSL_want_read (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

0 : false
1 : true

Description:

check if SSL want to read

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_want_read(ssl);
}

3.38 int SSL_want_write (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

0 : false
1 : true

Description:

check if SSL want to write

Example:

void example(void)
{
    SSL *ssl;
    int ret;

    ... ...

    ret = SSL_want_write(ssl);
}

Chapter 4. SSL X509 Certification and Private Key Function¶

4.1 X509 * d2i_X509 (X509 ** cert, const unsigned char * buffer, long len)

Arguments:

cert   - a point pointed to X509 certification
buffer - a point pointed to the certification context memory point
length - certification bytes

Return:

X509 certification object point

Description:

load a character certification context into system context. If '*cert' is pointed to the
certification, then load certification into it. Or create a new X509 certification object

Example:

void example(void)
{
    X509 *new;
    X509 *cert;
    unsigned char *buffer;
    long len;
    ... ...

    new = d2i_X509(&cert, buffer, len);
}

4.2 int SSL_add_client_CA (SSL * ssl, X509 * x)

Arguments:

ssl - SSL point
x   - CA certification point

Return:

1 : OK
0 : failed

Description:

add CA client certification into the SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    X509 *new;

    ... ...

    ret = SSL_add_client_CA(ssl, new);
}

4.3 int SSL_CTX_add_client_CA (SSL_CTX * ctx, X509 * x)

Arguments:

ctx - SSL context point
 x   - CA certification point

Return:

1 : OK
0 : failed

Description:

add CA client certification into the SSL context

Example:

void example(void)
{
    int ret;
    SSL_CTX *ctx;
    X509 *new;

    ... ...

    ret = SSL_add_clSSL_CTX_add_client_CAient_CA(ctx, new);
}

4.4 X509* SSL_get_certificate (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

SSL certification point

Description:

get the SSL certification point

Example:

void example(void)
{
    SSL *ssl;
    X509 *cert;

    ... ...

    cert = SSL_get_certificate(ssl);
}

4.5 long SSL_get_verify_result (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

the result of verifying

Description:

get the verifying result of the SSL certification

Example:

void example(void)
{
    SSL *ssl;
    long ret;

    ... ...

    ret = SSL_get_verify_result(ssl);
}

4.6 int SSL_CTX_use_certificate (SSL_CTX * ctx, X509 * x)

Arguments:

ctx  - the SSL context point
pkey - certification object point

Return:

1 : OK
0 : failed

Description:

load the certification into the SSL_CTX or SSL object

Example:

void example(void)
{
    int ret;
    SSL_CTX *ctx
    X509 *new;

    ... ...

    ret = SSL_CTX_use_certificate(ctx, new);
}

4.7 int SSL_CTX_use_certificate_ASN1 (SSL_CTX * ctx, int len, const unsigned char * d)

Arguments:

ctx - SSL context point
len - certification length
d   - data point

Return:

1 : OK
0 : failed

Description:

load the ASN1 certification into SSL context

Example:

void example(void)
{
    int ret;
    SSL_CTX *ctx;
    const unsigned char *buf;
    int len;

    ... ...

    ret = SSL_CTX_use_certificate_ASN1(ctx, len, buf);
}

4.8 int SSL_CTX_use_PrivateKey (SSL_CTX * ctx, EVP_PKEY * pkey)

Arguments:

ctx - SSL context point
pkey - private key object point

Return:

1 : OK
0 : failed

Description:

load the private key into the context object

Example:

void example(void)
{
    int ret;
    SSL_CTX *ctx;
    EVP_PKEY *pkey;

    ... ...

    ret = SSL_CTX_use_PrivateKey(ctx, pkey);
}

4.9 int SSL_CTX_use_PrivateKey_ASN1 (int pk, SSL_CTX * ctx, const unsigned char * d, long len)

Arguments:

ctx - SSL context point
d   - data point
len - private key length

Return:

1 : OK
0 : failed

Description:

load the ASN1 private key into SSL context

Example:

void example(void)
{
    int ret;
    int pk;
    SSL_CTX *ctx;
    const unsigned char *buf;
    long len;

    ... ...

    ret = SSL_CTX_use_PrivateKey_ASN1(pk, ctx, buf, len);
}

4.10 int SSL_CTX_use_RSAPrivateKey_ASN1 (SSL_CTX * ctx, const unsigned char * d, long len)

Arguments:

ctx - SSL context point
d   - data point
len - private key length

Return:

1 : OK
0 : failed

Description:

load the RSA ASN1 private key into SSL context

Example:

void example(void)
{
    int ret;
    SSL_CTX *ctx;
    const unsigned char *buf;
    long len;

    ... ...

    ret = SSL_CTX_use_RSAPrivateKey_ASN1(ctx, buf, len);
}

4.11 int SSL_use_certificate_ASN1 (SSL * ssl, int len, const unsigned char * d)

Arguments:

ssl - SSL point
len - data bytes
d   - data point

Return:

1 : OK
0 : failed

Description:

load certification into the SSL

Example:

void example(void)
{
    int ret;
    SSL *ssl;
    const unsigned char *buf;
    long len;

    ... ...

    ret = SSL_use_certificate_ASN1(ssl, len, buf);
}

4.12 X509* SSL_get_peer_certificate (const SSL * ssl)

Arguments:

ssl - SSL point

Return:

peer certification

Description:

get peer certification

Example:

void example(void)
{
    SSL *ssl;
    X509 *peer;

    ... ...

    peer = SSL_get_peer_certificate(ssl);
}

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