Move libssl's internals into the bssl namespace.

This is horrible, but everything else I tried was worse. The goal with
this CL is to take the extern "C" out of ssl/internal.h and move most
symbols to namespace bssl, so we can start using C++ helpers and
destructors without worry.

Complications:

- Public API functions must be extern "C" and match their declaration in
  ssl.h, which is unnamespaced. C++ really does not want you to
  interleave namespaced and unnamespaced things. One can actually write
  a namespaced extern "C" function, but this means, from C++'s
  perspective, the function is namespaced. Trying to namespace the
  public header would worked but ended up too deep a rabbithole.

- Our STACK_OF macros do not work right in namespaces.

- The typedefs for our exposed but opaque types are visible in the
  header files and copied into consuming projects as forward
  declarations. We ultimately want to give SSL a destructor, but
  clobbering an unnamespaced ssl_st::~ssl_st seems bad manners.

- MSVC complains about ambiguous names if one typedefs SSL to bssl::SSL.

This CL opts for:

- ssl/*.cc must begin with #define BORINGSSL_INTERNAL_CXX_TYPES. This
  informs the public headers to create forward declarations which are
  compatible with our namespaces.

- For now, C++-defined type FOO ends up at bssl::FOO with a typedef
  outside. Later I imagine we'll rename many of them.

- Internal functions get namespace bssl, so we stop worrying about
  stomping the tls1_prf symbol. Exported C functions are stuck as they
  are. Rather than try anything weird, bite the bullet and reorder files
  which have a mix of public and private functions. I expect that over
  time, the public functions will become fairly small as we move logic
  to more idiomatic C++.

  Files without any public C functions can just be written normally.

- To avoid MSVC troubles, some bssl types are renamed to CPlusPlusStyle
  in advance of them being made idiomatic C++.

Bug: 132
Change-Id: Ic931895e117c38b14ff8d6e5a273e868796c7581
Reviewed-on: https://boringssl-review.googlesource.com/18124
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/ssl/ssl_cert.cc b/ssl/ssl_cert.cc
index a9f334e..61d35b9 100644
--- a/ssl/ssl_cert.cc
+++ b/ssl/ssl_cert.cc
@@ -112,6 +112,8 @@
  * ECC cipher suite support in OpenSSL originally developed by
  * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project. */
 
+#define BORINGSSL_INTERNAL_CXX_TYPES
+
 #include <openssl/ssl.h>
 
 #include <assert.h>
@@ -131,6 +133,8 @@
 #include "internal.h"
 
 
+namespace bssl {
+
 CERT *ssl_cert_new(const SSL_X509_METHOD *x509_method) {
   CERT *ret = (CERT *)OPENSSL_malloc(sizeof(CERT));
   if (ret == NULL) {
@@ -340,20 +344,6 @@
   return 1;
 }
 
-int SSL_set_chain_and_key(SSL *ssl, CRYPTO_BUFFER *const *certs,
-                          size_t num_certs, EVP_PKEY *privkey,
-                          const SSL_PRIVATE_KEY_METHOD *privkey_method) {
-  return cert_set_chain_and_key(ssl->cert, certs, num_certs, privkey,
-                                privkey_method);
-}
-
-int SSL_CTX_set_chain_and_key(SSL_CTX *ctx, CRYPTO_BUFFER *const *certs,
-                              size_t num_certs, EVP_PKEY *privkey,
-                              const SSL_PRIVATE_KEY_METHOD *privkey_method) {
-  return cert_set_chain_and_key(ctx->cert, certs, num_certs, privkey,
-                                privkey_method);
-}
-
 int ssl_set_cert(CERT *cert, CRYPTO_BUFFER *buffer) {
   switch (check_leaf_cert_and_privkey(buffer, cert->privatekey)) {
     case leaf_cert_and_privkey_error:
@@ -393,29 +383,6 @@
   return 1;
 }
 
-int SSL_CTX_use_certificate_ASN1(SSL_CTX *ctx, size_t der_len,
-                                 const uint8_t *der) {
-  CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new(der, der_len, NULL);
-  if (buffer == NULL) {
-    return 0;
-  }
-
-  const int ok = ssl_set_cert(ctx->cert, buffer);
-  CRYPTO_BUFFER_free(buffer);
-  return ok;
-}
-
-int SSL_use_certificate_ASN1(SSL *ssl, const uint8_t *der, size_t der_len) {
-  CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new(der, der_len, NULL);
-  if (buffer == NULL) {
-    return 0;
-  }
-
-  const int ok = ssl_set_cert(ssl->cert, buffer);
-  CRYPTO_BUFFER_free(buffer);
-  return ok;
-}
-
 int ssl_has_certificate(const SSL *ssl) {
   return ssl->cert->chain != NULL &&
          sk_CRYPTO_BUFFER_value(ssl->cert->chain, 0) != NULL &&
@@ -781,31 +748,6 @@
   return CBB_flush(cbb);
 }
 
-void SSL_CTX_set_cert_cb(SSL_CTX *ctx, int (*cb)(SSL *ssl, void *arg),
-                         void *arg) {
-  ssl_cert_set_cert_cb(ctx->cert, cb, arg);
-}
-
-void SSL_set_cert_cb(SSL *ssl, int (*cb)(SSL *ssl, void *arg), void *arg) {
-  ssl_cert_set_cert_cb(ssl->cert, cb, arg);
-}
-
-STACK_OF(CRYPTO_BUFFER) *SSL_get0_peer_certificates(const SSL *ssl) {
-  SSL_SESSION *session = SSL_get_session(ssl);
-  if (session == NULL) {
-    return NULL;
-  }
-
-  return session->certs;
-}
-
-STACK_OF(CRYPTO_BUFFER) *SSL_get0_server_requested_CAs(const SSL *ssl) {
-  if (ssl->s3->hs == NULL) {
-    return NULL;
-  }
-  return ssl->s3->hs->ca_names;
-}
-
 int ssl_check_leaf_certificate(SSL_HANDSHAKE *hs, EVP_PKEY *pkey,
                                const CRYPTO_BUFFER *leaf) {
   SSL *const ssl = hs->ssl;
@@ -866,6 +808,72 @@
   return hs->local_pubkey != NULL;
 }
 
+}  // namespace bssl
+
+using namespace bssl;
+
+int SSL_set_chain_and_key(SSL *ssl, CRYPTO_BUFFER *const *certs,
+                          size_t num_certs, EVP_PKEY *privkey,
+                          const SSL_PRIVATE_KEY_METHOD *privkey_method) {
+  return cert_set_chain_and_key(ssl->cert, certs, num_certs, privkey,
+                                privkey_method);
+}
+
+int SSL_CTX_set_chain_and_key(SSL_CTX *ctx, CRYPTO_BUFFER *const *certs,
+                              size_t num_certs, EVP_PKEY *privkey,
+                              const SSL_PRIVATE_KEY_METHOD *privkey_method) {
+  return cert_set_chain_and_key(ctx->cert, certs, num_certs, privkey,
+                                privkey_method);
+}
+
+int SSL_CTX_use_certificate_ASN1(SSL_CTX *ctx, size_t der_len,
+                                 const uint8_t *der) {
+  CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new(der, der_len, NULL);
+  if (buffer == NULL) {
+    return 0;
+  }
+
+  const int ok = ssl_set_cert(ctx->cert, buffer);
+  CRYPTO_BUFFER_free(buffer);
+  return ok;
+}
+
+int SSL_use_certificate_ASN1(SSL *ssl, const uint8_t *der, size_t der_len) {
+  CRYPTO_BUFFER *buffer = CRYPTO_BUFFER_new(der, der_len, NULL);
+  if (buffer == NULL) {
+    return 0;
+  }
+
+  const int ok = ssl_set_cert(ssl->cert, buffer);
+  CRYPTO_BUFFER_free(buffer);
+  return ok;
+}
+
+void SSL_CTX_set_cert_cb(SSL_CTX *ctx, int (*cb)(SSL *ssl, void *arg),
+                         void *arg) {
+  ssl_cert_set_cert_cb(ctx->cert, cb, arg);
+}
+
+void SSL_set_cert_cb(SSL *ssl, int (*cb)(SSL *ssl, void *arg), void *arg) {
+  ssl_cert_set_cert_cb(ssl->cert, cb, arg);
+}
+
+STACK_OF(CRYPTO_BUFFER) *SSL_get0_peer_certificates(const SSL *ssl) {
+  SSL_SESSION *session = SSL_get_session(ssl);
+  if (session == NULL) {
+    return NULL;
+  }
+
+  return session->certs;
+}
+
+STACK_OF(CRYPTO_BUFFER) *SSL_get0_server_requested_CAs(const SSL *ssl) {
+  if (ssl->s3->hs == NULL) {
+    return NULL;
+  }
+  return ssl->s3->hs->ca_names;
+}
+
 static int set_signed_cert_timestamp_list(CERT *cert, const uint8_t *list,
                                            size_t list_len) {
   CBS sct_list;