Move handshake method hooks to SSL_PROTOCOL_METHOD.

None of these are version-specific. SSL_PROTOCOL_METHOD's interface will change
later, but this gets us closer to folding away SSL3_ENC_METHOD.

Change-Id: Ib427cdff32d0701a18fe42a52cdbf798f82ba956
Reviewed-on: https://boringssl-review.googlesource.com/3769
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index fd92fae..48cc81f 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -82,8 +82,6 @@
 
 static void get_current_time(SSL *ssl, OPENSSL_timeval *out_clock);
 static OPENSSL_timeval *dtls1_get_timeout(SSL *s, OPENSSL_timeval *timeleft);
-static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
-static int dtls1_handshake_write(SSL *s);
 
 const SSL3_ENC_METHOD DTLSv1_enc_data = {
   tls1_enc,
@@ -98,9 +96,6 @@
   tls1_alert_code,
   tls1_export_keying_material,
   SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV,
-  DTLS1_HM_HEADER_LENGTH,
-  dtls1_set_handshake_header,
-  dtls1_handshake_write,
 };
 
 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
@@ -117,9 +112,6 @@
   tls1_export_keying_material,
   SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS |
       SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
-  DTLS1_HM_HEADER_LENGTH,
-  dtls1_set_handshake_header,
-  dtls1_handshake_write,
 };
 
 int dtls1_new(SSL *s) {
@@ -413,7 +405,7 @@
 #endif
 }
 
-static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len) {
+int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len) {
   uint8_t *message = (uint8_t *)s->init_buf->data;
   const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
   uint8_t serialised_header[DTLS1_HM_HEADER_LENGTH];
@@ -440,6 +432,6 @@
          ssl3_finish_mac(s, message + DTLS1_HM_HEADER_LENGTH, len);
 }
 
-static int dtls1_handshake_write(SSL *s) {
+int dtls1_handshake_write(SSL *s) {
   return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
 }
diff --git a/ssl/d1_meth.c b/ssl/d1_meth.c
index a894222..34a2098 100644
--- a/ssl/d1_meth.c
+++ b/ssl/d1_meth.c
@@ -81,6 +81,9 @@
   ssl_undefined_void_function,
   ssl3_callback_ctrl,
   ssl3_ctx_callback_ctrl,
+  DTLS1_HM_HEADER_LENGTH,
+  dtls1_set_handshake_header,
+  dtls1_handshake_write,
 };
 
 const SSL_METHOD *DTLS_method(void) {
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 129a128..910a051 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -2019,7 +2019,7 @@
   }
 
   /* SSL3_ST_CW_KEY_EXCH_B */
-  return s->enc_method->do_write(s);
+  return s->method->do_write(s);
 
 err:
   BN_CTX_free(bn_ctx);
diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 1b342c0..3ad526c 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -570,9 +570,6 @@
     (int (*)(SSL *, uint8_t *, size_t, const char *, size_t, const uint8_t *,
              size_t, int use_context)) ssl_undefined_function,
     0,
-    SSL3_HM_HEADER_LENGTH,
-    ssl3_set_handshake_header,
-    ssl3_handshake_write,
 };
 
 int ssl3_num_ciphers(void) { return SSL3_NUM_CIPHERS; }
diff --git a/ssl/s3_meth.c b/ssl/s3_meth.c
index 5a25d7b..f8375a1 100644
--- a/ssl/s3_meth.c
+++ b/ssl/s3_meth.c
@@ -80,6 +80,9 @@
     ssl_undefined_void_function,
     ssl3_callback_ctrl,
     ssl3_ctx_callback_ctrl,
+    SSL3_HM_HEADER_LENGTH,
+    ssl3_set_handshake_header,
+    ssl3_handshake_write,
 };
 
 const SSL_METHOD *TLS_method(void) {
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 9986bd3..59180f6 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -559,6 +559,12 @@
   int (*ssl_version)(void);
   long (*ssl_callback_ctrl)(SSL *s, int cb_id, void (*fp)(void));
   long (*ssl_ctx_callback_ctrl)(SSL_CTX *s, int cb_id, void (*fp)(void));
+  /* Handshake header length */
+  unsigned int hhlen;
+  /* Set the handshake header */
+  int (*set_handshake_header)(SSL *s, int type, unsigned long len);
+  /* Write out handshake message */
+  int (*do_write)(SSL *s);
 };
 
 /* This is for the SSLv3/TLSv1.0 differences in crypto/hash stuff It is a bit
@@ -581,20 +587,14 @@
                                 const uint8_t *, size_t, int use_context);
   /* Various flags indicating protocol version requirements */
   unsigned int enc_flags;
-  /* Handshake header length */
-  unsigned int hhlen;
-  /* Set the handshake header */
-  int (*set_handshake_header)(SSL *s, int type, unsigned long len);
-  /* Write out handshake message */
-  int (*do_write)(SSL *s);
 };
 
-#define SSL_HM_HEADER_LENGTH(s) s->enc_method->hhlen
+#define SSL_HM_HEADER_LENGTH(s) s->method->hhlen
 #define ssl_handshake_start(s) \
-  (((uint8_t *)s->init_buf->data) + s->enc_method->hhlen)
+  (((uint8_t *)s->init_buf->data) + s->method->hhlen)
 #define ssl_set_handshake_header(s, htype, len) \
-  s->enc_method->set_handshake_header(s, htype, len)
-#define ssl_do_write(s) s->enc_method->do_write(s)
+  s->method->set_handshake_header(s, htype, len)
+#define ssl_do_write(s) s->method->do_write(s)
 
 /* Values for enc_flags */
 
@@ -817,6 +817,9 @@
 void dtls1_reset_seq_numbers(SSL *s, int rw);
 int dtls1_check_timeout_num(SSL *s);
 int dtls1_handle_timeout(SSL *s);
+int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
+int dtls1_handshake_write(SSL *s);
+
 const SSL_CIPHER *dtls1_get_cipher(unsigned int u);
 void dtls1_start_timer(SSL *s);
 void dtls1_stop_timer(SSL *s);
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 20b8c99..dae9a07 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -139,9 +139,6 @@
     tls1_alert_code,
     tls1_export_keying_material,
     0,
-    SSL3_HM_HEADER_LENGTH,
-    ssl3_set_handshake_header,
-    ssl3_handshake_write,
 };
 
 const SSL3_ENC_METHOD TLSv1_1_enc_data = {
@@ -157,9 +154,6 @@
     tls1_alert_code,
     tls1_export_keying_material,
     SSL_ENC_FLAG_EXPLICIT_IV,
-    SSL3_HM_HEADER_LENGTH,
-    ssl3_set_handshake_header,
-    ssl3_handshake_write,
 };
 
 const SSL3_ENC_METHOD TLSv1_2_enc_data = {
@@ -176,9 +170,6 @@
     tls1_export_keying_material,
     SSL_ENC_FLAG_EXPLICIT_IV|SSL_ENC_FLAG_SIGALGS|SSL_ENC_FLAG_SHA256_PRF
             |SSL_ENC_FLAG_TLS1_2_CIPHERS,
-    SSL3_HM_HEADER_LENGTH,
-    ssl3_set_handshake_header,
-    ssl3_handshake_write,
 };
 
 static int compare_uint16_t(const void *p1, const void *p2) {