Move to callback for session tickets
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 688248f..06a6c0b 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -413,8 +413,11 @@
     int ret;
     mbedtls_ssl_session session;
 
-    if( ssl->conf->session_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED )
+    if( ssl->conf->f_ticket_parse == NULL ||
+        ssl->conf->f_ticket_write == NULL )
+    {
         return( 0 );
+    }
 
     /* Remember the client asked us to send a new ticket */
     ssl->handshake->new_session_ticket = 1;
@@ -435,11 +438,18 @@
     /*
      * Failures are ok: just ignore the ticket and proceed.
      */
-    if( ( ret = mbedtls_ssl_ticket_parse( ssl->conf->ticket_keys, &session,
-                                          buf, len ) ) != 0 )
+    if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
+                                           buf, len ) ) != 0 )
     {
         mbedtls_ssl_session_free( &session );
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
+
+        if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
+        else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
+        else
+            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
+
         return( 0 );
     }
 
@@ -3525,7 +3535,7 @@
      * 10 .  9+n ticket content
      */
 
-    if( ( ret = mbedtls_ssl_ticket_write( ssl->conf->ticket_keys,
+    if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
                                 ssl->session_negotiate,
                                 ssl->out_msg + 10,
                                 ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN,
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 181f045..c1881b7 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -39,6 +39,56 @@
 
 #include <string.h>
 
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
+}
+
+/*
+ * Initialze context
+ */
+void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx )
+{
+    memset( ctx, 0, sizeof( mbedtls_ssl_ticket_context ) );
+}
+
+/*
+ * Setup context for actual use
+ */
+int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx,
+    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+    uint32_t lifetime )
+{
+    int ret;
+    unsigned char buf[16];
+
+    ctx->f_rng = f_rng;
+    ctx->p_rng = p_rng;
+
+    ctx->ticket_lifetime = lifetime;
+
+    mbedtls_aes_init( &ctx->enc );
+    mbedtls_aes_init( &ctx->dec );
+
+    if( ( ret = f_rng( p_rng, ctx->key_name, 16 ) != 0 ) ||
+        ( ret = f_rng( p_rng, ctx->mac_key,  16 ) != 0 ) ||
+        ( ret = f_rng( p_rng, buf,           16 ) != 0 ) )
+    {
+        return( ret );
+    }
+
+    if( ( ret = mbedtls_aes_setkey_enc( &ctx->enc, buf, 128 ) ) != 0 ||
+        ( ret = mbedtls_aes_setkey_dec( &ctx->dec, buf, 128 ) ) != 0 )
+    {
+        mbedtls_ssl_ticket_free( ctx );
+        return( ret );
+    }
+
+    mbedtls_zeroize( buf, sizeof( buf ) );
+
+    return( 0 );
+}
+
 /*
  * Serialize a session in the following format:
  *  0   .   n-1     session structure, n = sizeof(mbedtls_ssl_session)
@@ -170,7 +220,7 @@
                               uint32_t *ticket_lifetime )
 {
     int ret;
-    mbedtls_ssl_ticket_keys *ctx = p_ticket;
+    mbedtls_ssl_ticket_context *ctx = p_ticket;
     unsigned char *p = start;
     unsigned char *state;
     unsigned char iv[16];
@@ -194,7 +244,8 @@
     p += 16;
 
     /* Generate and write IV (with a copy for aes_crypt) */
-    memset( p, 0x2a, 16 ); /* Temporary WIP */
+    if( ( ret = ctx->f_rng( ctx->p_rng, p, 16 ) ) != 0 )
+        return( ret );
     memcpy( iv, p, 16 );
     p += 16;
 
@@ -244,7 +295,7 @@
                               size_t len )
 {
     int ret;
-    mbedtls_ssl_ticket_keys *ctx = p_ticket;
+    mbedtls_ssl_ticket_context *ctx = p_ticket;
     unsigned char *key_name = buf;
     unsigned char *iv = buf + 16;
     unsigned char *enc_len_p = iv + 16;
@@ -317,4 +368,15 @@
     return( 0 );
 }
 
+/*
+ * Free context
+ */
+void mbedtls_ssl_ticket_free( mbedtls_ssl_ticket_context *ctx )
+{
+    mbedtls_aes_free( &ctx->enc );
+    mbedtls_aes_free( &ctx->dec );
+
+    mbedtls_zeroize( ctx, sizeof( mbedtls_ssl_ticket_context ) );
+}
+
 #endif /* MBEDTLS_SSL_TICKET_C */
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 25a4deb..8241100 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5146,56 +5146,6 @@
     return( 0 );
 }
 
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-static void ssl_ticket_keys_free( mbedtls_ssl_ticket_keys *tkeys )
-{
-    mbedtls_aes_free( &tkeys->enc );
-    mbedtls_aes_free( &tkeys->dec );
-
-    mbedtls_zeroize( tkeys, sizeof(mbedtls_ssl_ticket_keys) );
-}
-
-/*
- * Allocate and initialize ticket keys
- */
-static int ssl_ticket_keys_init( mbedtls_ssl_config *conf )
-{
-    int ret;
-    mbedtls_ssl_ticket_keys *tkeys;
-    unsigned char buf[16];
-
-    if( conf->ticket_keys != NULL )
-        return( 0 );
-
-    tkeys = mbedtls_malloc( sizeof(mbedtls_ssl_ticket_keys) );
-    if( tkeys == NULL )
-        return( MBEDTLS_ERR_SSL_MALLOC_FAILED );
-
-    mbedtls_aes_init( &tkeys->enc );
-    mbedtls_aes_init( &tkeys->dec );
-
-    /* Temporary WIP! Using hardcoded keys. This is to remove the dependency
-     * on the RNG and allow puttint the keys in conf. Key generation will soon
-     * be move outside the main SSL module anyway. */
-
-    memset( tkeys->key_name, 'x', 16 );
-    memset( tkeys->mac_key, 0x2a, 16 );
-    memset( buf, 0x2a, 16 );
-
-    if( ( ret = mbedtls_aes_setkey_enc( &tkeys->enc, buf, 128 ) ) != 0 ||
-        ( ret = mbedtls_aes_setkey_dec( &tkeys->dec, buf, 128 ) ) != 0 )
-    {
-        ssl_ticket_keys_free( tkeys );
-        mbedtls_free( tkeys );
-        return( ret );
-    }
-
-    conf->ticket_keys = tkeys;
-
-    return( 0 );
-}
-#endif /* MBEDTLS_SSL_SESSION_TICKETS */
-
 /*
  * SSL set accessors
  */
@@ -5691,20 +5641,17 @@
 {
     conf->session_tickets = use_tickets;
 
-#if defined(MBEDTLS_SSL_CLI_C)
-    if( conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
-        return( 0 );
-#endif
-
-    if( use_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED )
-        return( 0 );
-
-    return( ssl_ticket_keys_init( conf ) );
+    return( 0 );
 }
 
-void mbedtls_ssl_conf_session_ticket_lifetime( mbedtls_ssl_config *conf, int lifetime )
+void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
+        mbedtls_ssl_ticket_write_t *f_ticket_write,
+        mbedtls_ssl_ticket_parse_t *f_ticket_parse,
+        void *p_ticket )
 {
-    conf->ticket_keys->ticket_lifetime = lifetime;
+    conf->f_ticket_write = f_ticket_write;
+    conf->f_ticket_parse = f_ticket_parse;
+    conf->p_ticket       = p_ticket;
 }
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
@@ -6699,11 +6646,6 @@
     conf->cbc_record_splitting = MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED;
 #endif
 
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    ssl_ticket_keys_init( &conf );
-    conf->ticket_keys->ticket_lifetime = MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME;
-#endif
-
 #if defined(MBEDTLS_SSL_SET_CURVES)
     conf->curve_list = mbedtls_ecp_grp_id_list( );
 #endif
@@ -6765,14 +6707,6 @@
     }
 #endif
 
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    if( conf->ticket_keys )
-    {
-        ssl_ticket_keys_free( conf->ticket_keys );
-        mbedtls_free( conf->ticket_keys );
-    }
-#endif
-
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
     ssl_key_cert_free( conf->key_cert );
 #endif