Implement a human readable state function for the record layer

This allows querying of the record layer to get a human readable state
string out. This resolves two outstanding TODO comments and enables us
to remove the rstate variable from s->rlayer.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #18132)

ssl/record/methods/dtls_meth.c

@@ -728,5 +728,6 @@ const OSSL_RECORD_METHOD ossl_dtls_record_method = {
     NULL,
     tls_set_first_handshake,
     tls_set_max_pipelines,
-    dtls_set_in_init
+    dtls_set_in_init,
+    tls_get_state
 };

ssl/record/methods/ktls_meth.c

@@ -542,5 +542,6 @@ const OSSL_RECORD_METHOD ossl_ktls_record_method = {
     tls_set_plain_alerts,
     tls_set_first_handshake,
     tls_set_max_pipelines,
-    NULL
+    NULL,
+    tls_get_state
 };

ssl/record/methods/recmethod_local.h

@@ -284,4 +284,6 @@ int tls_set_protocol_version(OSSL_RECORD_LAYER *rl, int version);
 void tls_set_plain_alerts(OSSL_RECORD_LAYER *rl, int allow);
 void tls_set_first_handshake(OSSL_RECORD_LAYER *rl, int first);
 void tls_set_max_pipelines(OSSL_RECORD_LAYER *rl, size_t max_pipelines);
+void tls_get_state(OSSL_RECORD_LAYER *rl, const char **shortstr,
+                   const char **longstr);
 int rlayer_setup_read_buffer(OSSL_RECORD_LAYER *rl);

ssl/record/methods/tls_common.c

@@ -1341,6 +1341,29 @@ void tls_set_max_pipelines(OSSL_RECORD_LAYER *rl, size_t max_pipelines)
         rl->read_ahead = 1;
 }
 
+void tls_get_state(OSSL_RECORD_LAYER *rl, const char **shortstr,
+                   const char **longstr)
+{
+    const char *shrt, *lng;
+    switch (rl->rstate) {
+    case SSL_ST_READ_HEADER:
+        shrt = "RH";
+        lng = "read header";
+        break;
+    case SSL_ST_READ_BODY:
+        shrt = "RB";
+        lng = "read body";
+        break;
+    default:
+        shrt = lng = "unknown";
+        break;
+    }
+    if (shortstr != NULL)
+        *shortstr = shrt;
+    if (longstr != NULL)
+        *longstr = lng;
+}
+
 const OSSL_RECORD_METHOD ossl_tls_record_method = {
     tls_new_record_layer,
     tls_free,
@@ -1361,5 +1384,6 @@ const OSSL_RECORD_METHOD ossl_tls_record_method = {
     tls_set_plain_alerts,
     tls_set_first_handshake,
     tls_set_max_pipelines,
-    NULL
+    NULL,
+    tls_get_state
 };

ssl/record/rec_layer_s3.c

@@ -34,8 +34,6 @@ void RECORD_LAYER_init(RECORD_LAYER *rl, SSL_CONNECTION *s)
 
 void RECORD_LAYER_clear(RECORD_LAYER *rl)
 {
-    rl->rstate = SSL_ST_READ_HEADER;
-
     rl->wnum = 0;
     memset(rl->handshake_fragment, 0, sizeof(rl->handshake_fragment));
     rl->handshake_fragment_len = 0;
@@ -141,43 +139,34 @@ void SSL_set_default_read_buffer_len(SSL *s, size_t len)
 const char *SSL_rstate_string_long(const SSL *s)
 {
     const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
+    const char *lng;
 
     if (sc == NULL)
         return NULL;
 
-    /* TODO(RECLAYER): Fix me */
-    switch (sc->rlayer.rstate) {
-    case SSL_ST_READ_HEADER:
-        return "read header";
-    case SSL_ST_READ_BODY:
-        return "read body";
-    case SSL_ST_READ_DONE:
-        return "read done";
-    default:
+    if (sc->rlayer.rrlmethod == NULL || sc->rlayer.rrl == NULL)
         return "unknown";
-    }
+
+    sc->rlayer.rrlmethod->get_state(sc->rlayer.rrl, NULL, &lng);
+
+    return lng;
 }
 
 const char *SSL_rstate_string(const SSL *s)
 {
     const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
+    const char *shrt;
 
     if (sc == NULL)
         return NULL;
 
-    /* TODO(RECLAYER): Fix me */
-    switch (sc->rlayer.rstate) {
-    case SSL_ST_READ_HEADER:
-        return "RH";
-    case SSL_ST_READ_BODY:
-        return "RB";
-    case SSL_ST_READ_DONE:
-        return "RD";
-    default:
+    if (sc->rlayer.rrlmethod == NULL || sc->rlayer.rrl == NULL)
         return "unknown";
-    }
-}
 
+    sc->rlayer.rrlmethod->get_state(sc->rlayer.rrl, &shrt, NULL);
+
+    return shrt;
+}
 
 /*
  * Call this to write data in records of type 'type' It will return <= 0 if

ssl/record/record.h

@@ -163,8 +163,6 @@ typedef struct record_layer_st {
      * non-blocking reads)
      */
     int read_ahead;
-    /* where we are when reading */
-    int rstate;
     /* How many pipelines can be used to write data */
     size_t numwpipes;
     /* write IO goes into here */

ssl/record/recordmethod.h

@@ -314,6 +314,12 @@ struct ossl_record_method_st {
      * not. Default at creation of the record layer is "yes".
      */
     void (*set_in_init)(OSSL_RECORD_LAYER *rl, int in_init);
+
+    /*
+     * Get a short or long human readable description of the record layer state
+     */
+    void (*get_state)(OSSL_RECORD_LAYER *rl, const char **shortstr,
+                      const char **longstr);
 };