Remove ssl/record/README.md

This file contains design details for the old record layer and is no
longer relevant for the new design.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18132)

diff --git a/ssl/record/README.md b/ssl/record/README.md
deleted file mode 100644 (file)
index 263f257..0000000
--- a/ssl/record/README.md
+++ /dev/null
@@ -1,73 +0,0 @@
-Record Layer Design
-===================
-
-This file provides some guidance on the thinking behind the design of the
-record layer code to aid future maintenance.
-
-The record layer is divided into a number of components. At the time of writing
-there are four: SSL3_RECORD, SSL3_BUFFER, DLTS1_BITMAP and RECORD_LAYER. Each
-of these components is defined by:
-1) A struct definition of the same name as the component
-2) A set of source files that define the functions for that component
-3) A set of accessor macros
-
-All struct definitions are in record.h. The functions and macros are either
-defined in record.h or record_local.h dependent on whether they are intended to
-be private to the record layer, or whether they form part of the API to the rest
-of libssl.
-
-The source files map to components as follows:
-
-    dtls1_bitmap.c                 -> DTLS1_BITMAP component
-    ssl3_buffer.c                  -> SSL3_BUFFER component
-    ssl3_record.c                  -> SSL3_RECORD component
-    rec_layer_s3.c, rec_layer_d1.c -> RECORD_LAYER component
-
-The RECORD_LAYER component is a facade pattern, i.e. it provides a simplified
-interface to the record layer for the rest of libssl. The other 3 components are
-entirely private to the record layer and therefore should never be accessed
-directly by libssl.
-
-Any component can directly access its own members - they are private to that
-component, e.g. ssl3_buffer.c can access members of the SSL3_BUFFER struct
-without using a macro. No component can directly access the members of another
-component, e.g. ssl3_buffer cannot reach inside the RECORD_LAYER component to
-directly access its members. Instead components use accessor macros, so if code
-in ssl3_buffer.c wants to access the members of the RECORD_LAYER it uses the
-RECORD_LAYER_* macros.
-
-Conceptually it looks like this:
-
-                          libssl
-                             |
-    -------------------------|-----record.h------------------------------------
-                             |
-                      _______V______________
-                     |                      |
-                     |    RECORD_LAYER      |
-                     |                      |
-                     |    rec_layer_s3.c    |
-                     |          ^           |
-                     | _________|__________ |
-                     ||                    ||
-                     || DTLS1_RECORD_LAYER ||
-                     ||                    ||
-                     || rec_layer_d1.c     ||
-                     ||____________________||
-                     |______________________|
-          record_local.h     ^   ^   ^
-           _________________|   |   |_________________
-          |                     |                     |
-     _____V_________      ______V________      _______V________
-    |               |    |               |    |                |
-    | SSL3_BUFFER   |    | SSL3_RECORD   |    | DTLS1_BITMAP   |
-    |               |--->|               |    |                |
-    | ssl3_buffer.c |    | ssl3_record.c |    | dtls1_bitmap.c |
-    |_______________|    |_______________|    |________________|
-
-The two RECORD_LAYER source files build on each other, i.e.
-the main one is rec_layer_s3.c which provides the core SSL/TLS layer. The second
-one is rec_layer_d1.c which builds off of the SSL/TLS code to provide DTLS
-specific capabilities. It uses some DTLS specific RECORD_LAYER component members
-which should only be accessed from rec_layer_d1.c. These are held in the
-DTLS1_RECORD_LAYER struct.