SSL_CTX_set_stateless_cookie_generate_cb, SSL_CTX_set_stateless_cookie_verify_cb - Callback functions for stateless TLS1.3 cookies
#include <openssl/ssl.h> void SSL_CTX_set_stateless_cookie_generate_cb( SSL_CTX *ctx, int (*gen_stateless_cookie_cb) (SSL *ssl, unsigned char *cookie, size_t *cookie_len)); void SSL_CTX_set_stateless_cookie_verify_cb( SSL_CTX *ctx, int (*verify_stateless_cookie_cb) (SSL *ssl, const unsigned char *cookie, size_t cookie_len));
SSL_CTX_set_cookie_generate_cb() sets the callback used by SSL_stateless(3) to generate the application-controlled portion of the cookie provided to clients in the HelloRetryRequest transmitted as a response to a ClientHello with a missing or invalid cookie. gen_stateless_cookie_cb() must write at most SSL_COOKIE_LENGTH bytes into cookie, and must write the number of bytes written to cookie_len. If a cookie cannot be generated, a zero return value can be used to abort the handshake.
SSL_CTX_set_cookie_verify_cb() sets the callback used by SSL_stateless(3) to determine whether the application-controlled portion of a ClientHello cookie is valid. A nonzero return value from app_verify_cookie_cb() communicates that the cookie is valid. The integrity of the entire cookie, including the application-controlled portion, is automatically verified by HMAC before verify_stateless_cookie_cb() is called.
Neither function returns a value.
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