+#ifndef OPENSSL_NO_PSK
+/* Default PSK identity and key */
+static char *psk_identity="Client_identity";
+static char *psk_key=NULL; /* by default PSK is not used */
+
+static unsigned int psk_client_cb(SSL *ssl, const char *hint, char *identity,
+ unsigned int max_identity_len, unsigned char *psk,
+ unsigned int max_psk_len)
+ {
+ unsigned int psk_len = 0;
+ int ret;
+ BIGNUM *bn=NULL;
+
+ if (c_debug)
+ BIO_printf(bio_c_out, "psk_client_cb\n");
+ if (!hint)
+ {
+ /* no ServerKeyExchange message*/
+ if (c_debug)
+ BIO_printf(bio_c_out,"NULL received PSK identity hint, continuing anyway\n");
+ }
+ else if (c_debug)
+ BIO_printf(bio_c_out, "Received PSK identity hint '%s'\n", hint);
+
+ /* lookup PSK identity and PSK key based on the given identity hint here */
+ ret = BIO_snprintf(identity, max_identity_len, psk_identity);
+ if (ret < 0 || (unsigned int)ret > max_identity_len)
+ goto out_err;
+ if (c_debug)
+ BIO_printf(bio_c_out, "created identity '%s' len=%d\n", identity, ret);
+ ret=BN_hex2bn(&bn, psk_key);
+ if (!ret)
+ {
+ BIO_printf(bio_err,"Could not convert PSK key '%s' to BIGNUM\n", psk_key);
+ if (bn)
+ BN_free(bn);
+ return 0;
+ }
+
+ if ((unsigned int)BN_num_bytes(bn) > max_psk_len)
+ {
+ BIO_printf(bio_err,"psk buffer of callback is too small (%d) for key (%d)\n",
+ max_psk_len, BN_num_bytes(bn));
+ BN_free(bn);
+ return 0;
+ }
+
+ psk_len=BN_bn2bin(bn, psk);
+ BN_free(bn);
+ if (psk_len == 0)
+ goto out_err;
+
+ if (c_debug)
+ BIO_printf(bio_c_out, "created PSK len=%d\n", psk_len);
+
+ return psk_len;
+ out_err:
+ if (c_debug)
+ BIO_printf(bio_err, "Error in PSK client callback\n");
+ return 0;
+ }
+#endif
+