empty pre_shared_key functions

To easy review

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 40e3cfd..645479b 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -665,56 +665,6 @@
     return ( 0 );
 }
 
-/* Check if we have any PSK to offer, returns 0 if a PSK is available. */
-MBEDTLS_CHECK_RETURN_CRITICAL
-static int ssl_tls13_get_psk_to_offer(
-        const mbedtls_ssl_context *ssl,
-        int *psk_type,
-        const unsigned char **psk, size_t *psk_len,
-        const unsigned char **psk_identity, size_t *psk_identity_len )
-{
-    *psk = NULL;
-    *psk_len = 0;
-    *psk_identity = NULL;
-    *psk_identity_len = 0;
-    *psk_type = MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL;
-
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    /* Check if a ticket has been configured. */
-    if( ssl->session_negotiate != NULL &&
-        ssl->session_negotiate->ticket != NULL )
-    {
-#if defined(MBEDTLS_HAVE_TIME)
-        mbedtls_time_t now = mbedtls_time( NULL );
-        if( ssl->session_negotiate->ticket_received <= now &&
-            (uint64_t)( now - ssl->session_negotiate->ticket_received )
-                    <= ssl->session_negotiate->ticket_lifetime )
-        {
-            *psk_type = MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION;
-            *psk = ssl->session_negotiate->resumption_key;
-            *psk_len = ssl->session_negotiate->resumption_key_len;
-            *psk_identity = ssl->session_negotiate->ticket;
-            *psk_identity_len = ssl->session_negotiate->ticket_len;
-            return( 0 );
-        }
-#endif /* MBEDTLS_HAVE_TIME */
-        MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket expired" ) );
-    }
-#endif
-
-    /* Check if an external PSK has been configured. */
-    if( ssl->conf->psk != NULL )
-    {
-        *psk = ssl->conf->psk;
-        *psk_len = ssl->conf->psk_len;
-        *psk_identity = ssl->conf->psk_identity;
-        *psk_identity_len = ssl->conf->psk_identity_len;
-        return( 0 );
-    }
-
-    return( MBEDTLS_ERR_ERROR_GENERIC_ERROR );
-}
-
 /*
  * mbedtls_ssl_tls13_write_identities_of_pre_shared_key_ext() structure:
  *
@@ -743,204 +693,53 @@
     unsigned char *buf, unsigned char *end,
     size_t *out_len, size_t *binders_len )
 {
-    unsigned char *p = buf;
-    const unsigned char *psk;
-    size_t psk_len;
-    const unsigned char *psk_identity;
-    size_t psk_identity_len;
-    int psk_type;
-    const mbedtls_ssl_ciphersuite_t *ciphersuite_info = NULL;
-    const int *ciphersuites;
-    psa_algorithm_t psa_hash_alg;
-    int hash_len = 0;
-    size_t identities_len, l_binders_len;
-    uint32_t obfuscated_ticket_age = 0;
-
-    *out_len = 0;
-    *binders_len = 0;
-
-    /* Check if we have any PSKs to offer. If so, return the first.
-     *
-     * NOTE: Ultimately, we want to be able to offer multiple PSKs,
-     *       in which case we want to iterate over them here.
-     *
-     * As it stands, however, we only ever offer one, chosen
-     * by the following heuristic:
-     * - If a ticket has been configured, offer the corresponding PSK.
-     * - If no ticket has been configured by an external PSK has been
-     *   configured, offer that.
-     * - Otherwise, skip the PSK extension.
-     */
-    if( ssl_tls13_get_psk_to_offer( ssl, &psk_type, &psk, &psk_len,
-                                    &psk_identity, &psk_identity_len ) != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip pre_shared_key extensions" ) );
-        return( 0 );
-    }
-
-    if( psk_type == MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL )
-    {
-        /*
-         * Ciphersuite list
-         */
-        ciphersuites = ssl->conf->ciphersuite_list;
-        for( int i = 0; ciphersuites[i] != 0; i++ )
-        {
-            ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(
-                                    ciphersuites[i] );
-
-            if( mbedtls_ssl_validate_ciphersuite(
-                                ssl, ciphersuite_info,
-                                MBEDTLS_SSL_VERSION_TLS1_3,
-                                MBEDTLS_SSL_VERSION_TLS1_3 ) != 0 )
-                continue;
-
-            /* In this implementation we only add one pre-shared-key
-             * extension.
-             */
-            ssl->session_negotiate->ciphersuite = ciphersuites[i];
-            break;
-        }
-    }
-    else
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    if( psk_type == MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION )
-    {
-#if defined(MBEDTLS_HAVE_TIME)
-        mbedtls_time_t now = mbedtls_time( NULL );
-
-        obfuscated_ticket_age =
-            ( (uint32_t)( now - ssl->session_negotiate->ticket_received ) * 1000 )
-              + ssl->session_negotiate->ticket_age_add;
-#endif
-    }
-    else
-#endif /* MBEDTLS_SSL_SESSION_TICKETS */
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "write_identities_of_pre_shared_key_ext: "
-                                    "should never happen" ) );
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-    }
-
-
-    ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(
-            ssl->session_negotiate->ciphersuite );
-    /* No suitable ciphersuite for the PSK */
-    if( ciphersuite_info  == NULL )
-        return( 0 );
-
-    psa_hash_alg = mbedtls_psa_translate_md( ciphersuite_info->mac );
-    hash_len = PSA_HASH_LENGTH( psa_hash_alg );
-    if( hash_len == -1 )
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-
-    /* Check if we have space to write the extension, binder included.
-     * - extension_type         (2 bytes)
-     * - extension_data_len     (2 bytes)
-     * - identities_len         (2 bytes)
-     * - identity_len           (2 bytes)
-     * - identity               (psk_identity_len bytes)
-     * - obfuscated_ticket_age  (4 bytes)
-     * - binders_len            (2 bytes)
-     * - binder_len             (1 byte)
-     * - binder                 (hash_len bytes)
-     */
-
-    identities_len = 6 + psk_identity_len;
-    l_binders_len = 1 + hash_len;
-
-    MBEDTLS_SSL_DEBUG_MSG( 3,
-                 ( "client hello, adding pre_shared_key extension, "
-                   "omitting PSK binder list" ) );
-
-    /* Extension header */
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 8 );
-    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_PRE_SHARED_KEY, p, 0 );
-    MBEDTLS_PUT_UINT16_BE( 2 + identities_len + 2 + l_binders_len , p, 2 );
-
-    MBEDTLS_PUT_UINT16_BE( identities_len, p, 4 );
-    MBEDTLS_PUT_UINT16_BE( psk_identity_len, p, 6 );
-    p += 8;
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, psk_identity_len );
-    memcpy( p, psk_identity, psk_identity_len );
-    p += psk_identity_len;
-
-    /* add obfuscated ticket age */
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
-    MBEDTLS_PUT_UINT32_BE( obfuscated_ticket_age, p, 0 );
-    p += 4;
-
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 + l_binders_len );
-    *out_len = ( p - buf ) + l_binders_len + 2;
-    *binders_len = l_binders_len + 2;
-
-    ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_PRE_SHARED_KEY;
-
+    ((void) ssl);
+    ((void) buf);
+    ((void) end);
+    ((void) out_len);
+    ((void) binders_len);
     return( 0 );
 }
 
 int mbedtls_ssl_tls13_write_binders_of_pre_shared_key_ext(
-    mbedtls_ssl_context *ssl,
-    unsigned char *buf, unsigned char *end )
+        mbedtls_ssl_context *ssl, unsigned char *buf, unsigned char *end )
 {
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    unsigned char *p = buf;
-    const unsigned char *psk_identity;
-    size_t psk_identity_len;
-    const mbedtls_ssl_ciphersuite_t *ciphersuite_info = NULL;
-    psa_algorithm_t psa_hash_alg;
-    int hash_len = 0;
-    const unsigned char *psk = NULL;
-    size_t psk_len = 0;
-    int psk_type;
-    unsigned char transcript[MBEDTLS_MD_MAX_SIZE];
-    size_t transcript_len;
-
-    if( ssl_tls13_get_psk_to_offer( ssl, &psk_type, &psk, &psk_len,
-                                    &psk_identity, &psk_identity_len ) != 0 )
-    {
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-    }
-
-    ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(
-            ssl->session_negotiate->ciphersuite );
-    if( ciphersuite_info  == NULL )
-        return( 0 );
-
-    psa_hash_alg = mbedtls_psa_translate_md( ciphersuite_info->mac );
-    hash_len = PSA_HASH_LENGTH( psa_hash_alg );
-    if( ( hash_len == -1 ) || ( ( end - buf ) != 3 + hash_len ) )
-        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-
-    MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding PSK binder list" ) );
-
-    MBEDTLS_SSL_CHK_BUF_PTR( p, end, 3 + hash_len );
-    /* 2 bytes length field for array of psk binders */
-    MBEDTLS_PUT_UINT16_BE( hash_len + 1, p, 0 );
-    p += 2;
-
-    /* 1 bytes length field for next psk binder */
-    *p++ = MBEDTLS_BYTE_0( hash_len );
-
-    /* Get current state of handshake transcript. */
-    ret = mbedtls_ssl_get_handshake_transcript( ssl, ciphersuite_info->mac,
-                                                transcript, sizeof( transcript ),
-                                                &transcript_len );
-    if( ret != 0 )
-        return( ret );
-
-    ret = mbedtls_ssl_tls13_create_psk_binder( ssl,
-              mbedtls_psa_translate_md( ciphersuite_info->mac ),
-              psk, psk_len, psk_type,
-              transcript, p );
-    if( ret != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_create_psk_binder", ret );
-        return( ret );
-    }
+    ((void) ssl);
+    ((void) buf);
+    ((void) end);
 
     return( 0 );
 }
+
+/*
+ * struct {
+ *   opaque identity<1..2^16-1>;
+ *   uint32 obfuscated_ticket_age;
+ * } PskIdentity;
+ *
+ * opaque PskBinderEntry<32..255>;
+ *
+ * struct {
+ *
+ *   select (Handshake.msg_type) {
+ *         ...
+ *         case server_hello: uint16 selected_identity;
+ *   };
+ *
+ * } PreSharedKeyExtension;
+ *
+ */
+MBEDTLS_CHECK_RETURN_CRITICAL
+static int ssl_tls13_parse_server_pre_shared_key_ext( mbedtls_ssl_context *ssl,
+                                                      const unsigned char *buf,
+                                                      const unsigned char *end )
+{
+    ((void) ssl);
+    ((void) buf);
+    ((void) end);
+    return( 0 );
+}
+
 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
 
 int mbedtls_ssl_tls13_write_client_hello_exts( mbedtls_ssl_context *ssl,
@@ -1299,92 +1098,6 @@
     return( 0 );
 }
 
-#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
-/*
- * struct {
- *   opaque identity<1..2^16-1>;
- *   uint32 obfuscated_ticket_age;
- * } PskIdentity;
- *
- * opaque PskBinderEntry<32..255>;
- *
- * struct {
- *
- *   select (Handshake.msg_type) {
- *         ...
- *         case server_hello: uint16 selected_identity;
- *   };
- *
- * } PreSharedKeyExtension;
- *
- */
-
-MBEDTLS_CHECK_RETURN_CRITICAL
-static int ssl_tls13_parse_server_pre_shared_key_ext( mbedtls_ssl_context *ssl,
-                                                      const unsigned char *buf,
-                                                      const unsigned char *end )
-{
-    int ret = 0;
-    size_t selected_identity;
-
-    int psk_type;
-    const unsigned char *psk;
-    size_t psk_len;
-    const unsigned char *psk_identity;
-    size_t psk_identity_len;
-
-    /* Check which PSK we've offered.
-     *
-     * NOTE: Ultimately, we want to offer multiple PSKs, and in this
-     *       case, we need to iterate over them here.
-     */
-    if( ssl_tls13_get_psk_to_offer( ssl, &psk_type, &psk, &psk_len,
-                                    &psk_identity, &psk_identity_len ) != 0 )
-    {
-        /* If we haven't offered a PSK, the server must not send
-         * a PSK identity extension. */
-        return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
-    }
-
-    MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 2 );
-    selected_identity = MBEDTLS_GET_UINT16_BE( buf, 0 );
-
-    /* We have offered only one PSK, so the only valid choice
-     * for the server is PSK index 0.
-     *
-     * This will change once we support multiple PSKs. */
-    if( selected_identity > 0 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "Server's chosen PSK identity out of range" ) );
-
-        if( ( ret = mbedtls_ssl_send_alert_message( ssl,
-                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                        MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ) ) != 0 )
-        {
-            return( ret );
-        }
-
-        return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
-    }
-
-    /* Set the chosen PSK
-     *
-     * TODO: We don't have to do this in case we offered 0-RTT and the
-     *       server accepted it, because in this case we've already
-     *       set the handshake PSK. */
-    ret = mbedtls_ssl_set_hs_psk( ssl, psk, psk_len );
-    if( ret != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_set_hs_psk", ret );
-        return( ret );
-    }
-
-    ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_PRE_SHARED_KEY;
-    return( 0 );
-}
-
-#endif
-
 /* Parse ServerHello message and configure context
  *
  * struct {