1SSL_CTX_set_psk_client_callback(3)  OpenSSL SSL_CTX_set_psk_client_callback(3)
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NAME

6       SSL_CTX_set_psk_client_callback, SSL_set_psk_client_callback - set PSK
7       client callback
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SYNOPSIS

10        #include <openssl/ssl.h>
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12        void SSL_CTX_set_psk_client_callback(SSL_CTX *ctx,
13               unsigned int (*callback)(SSL *ssl, const char *hint,
14               char *identity, unsigned int max_identity_len,
15               unsigned char *psk, unsigned int max_psk_len));
16        void SSL_set_psk_client_callback(SSL *ssl,
17               unsigned int (*callback)(SSL *ssl, const char *hint,
18               char *identity, unsigned int max_identity_len,
19               unsigned char *psk, unsigned int max_psk_len));
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DESCRIPTION

22       A client application must provide a callback function which is called
23       when the client is sending the ClientKeyExchange message to the server.
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25       The purpose of the callback function is to select the PSK identity and
26       the pre-shared key to use during the connection setup phase.
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28       The callback is set using functions SSL_CTX_set_psk_client_callback()
29       or SSL_set_psk_client_callback(). The callback function is given the
30       connection in parameter ssl, a NULL-terminated PSK identity hint sent
31       by the server in parameter hint, a buffer identity of length
32       max_identity_len bytes where the the resulting NULL-terminated identity
33       is to be stored, and a buffer psk of length max_psk_len bytes where the
34       resulting pre-shared key is to be stored.
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NOTES

37       Note that parameter hint given to the callback may be NULL.
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RETURN VALUES

40       Return values from the client callback are interpreted as follows:
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42       On success (callback found a PSK identity and a pre-shared key to use)
43       the length (> 0) of psk in bytes is returned.
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45       Otherwise or on errors callback should return 0. In this case the
46       connection setup fails.
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501.0.2k                            2017-01-26SSL_CTX_set_psk_client_callback(3)
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