Add initial state machine rewrite code

This is the first drop of the new state machine code.

The rewrite has the following objectives:
- Remove duplication of state code between client and server
- Remove duplication of state code between TLS and DTLS
- Simplify transitions and bring the logic together in a single location
  so that it is easier to validate
- Remove duplication of code between each of the message handling functions
- Receive a message first and then work out whether that is a valid
  transition - not the other way around (the other way causes lots of issues
  where we are expecting one type of message next but actually get something
  else)
- Separate message flow state from handshake state (in order to better
  understand each)
  - message flow state = when to flush buffers; handling restarts in the
    event of NBIO events; handling the common flow of steps for reading a
    message and the common flow of steps for writing a message etc
  - handshake state = what handshake message are we working on now
- Control complexity: only the state machine can change state: keep all
  the state changes local to a file

This builds on previous state machine related work:
- Surface CCS processing in the state machine
- Version negotiation rewrite

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index fb626279af..7788f098e6 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -1928,6 +1928,7 @@ void ERR_load_SSL_strings(void);
 # define SSL_F_DTLS1_SEND_SERVER_HELLO                    266
 # define SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE             267
 # define SSL_F_DTLS1_WRITE_APP_DATA_BYTES                 268
+# define SSL_F_READ_STATE_MACHINE                         352
 # define SSL_F_SSL3_ACCEPT                                128
 # define SSL_F_SSL3_ADD_CERT_TO_BUF                       296
 # define SSL_F_SSL3_CALLBACK_CTRL                         233
@@ -2085,6 +2086,7 @@ void ERR_load_SSL_strings(void);
 # define SSL_F_SSL_USE_RSAPRIVATEKEY_FILE                 206
 # define SSL_F_SSL_VERIFY_CERT_CHAIN                      207
 # define SSL_F_SSL_WRITE                                  208
+# define SSL_F_STATE_MACHINE                              353
 # define SSL_F_TLS12_CHECK_PEER_SIGALG                    333
 # define SSL_F_TLS1_CERT_VERIFY_MAC                       286
 # define SSL_F_TLS1_CHANGE_CIPHER_STATE                   209