Add support for GCM cipher suites from RFC 7714.

webrtc/base/sslstreamadapter.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 11 matching lines @@
 #endif  // SSL_USE_OPENSSL
 
 ///////////////////////////////////////////////////////////////////////////////
 
 namespace rtc {
 
 // TODO(guoweis): Move this to SDP layer and use int form internally.
 // webrtc:5043.
 const char CS_AES_CM_128_HMAC_SHA1_80[] = "AES_CM_128_HMAC_SHA1_80";
 const char CS_AES_CM_128_HMAC_SHA1_32[] = "AES_CM_128_HMAC_SHA1_32";
+const char CS_AEAD_AES_128_GCM[] = "AEAD_AES_128_GCM";
+const char CS_AEAD_AES_256_GCM[] = "AEAD_AES_256_GCM";
 
 std::string SrtpCryptoSuiteToName(int crypto_suite) {
-  if (crypto_suite == SRTP_AES128_CM_SHA1_32)
+  switch (crypto_suite) {
+  case SRTP_AES128_CM_SHA1_32:
     return CS_AES_CM_128_HMAC_SHA1_32;
-  if (crypto_suite == SRTP_AES128_CM_SHA1_80)
+  case SRTP_AES128_CM_SHA1_80:
     return CS_AES_CM_128_HMAC_SHA1_80;
-  return std::string();
+  case SRTP_AEAD_AES_128_GCM:
+    return CS_AEAD_AES_128_GCM;
+  case SRTP_AEAD_AES_256_GCM:
+    return CS_AEAD_AES_256_GCM;
+  default:
+    return std::string();
+  }
 }
 
 int SrtpCryptoSuiteFromName(const std::string& crypto_suite) {
   if (crypto_suite == CS_AES_CM_128_HMAC_SHA1_32)
     return SRTP_AES128_CM_SHA1_32;
   if (crypto_suite == CS_AES_CM_128_HMAC_SHA1_80)
     return SRTP_AES128_CM_SHA1_80;
+  if (crypto_suite == CS_AEAD_AES_128_GCM)
+    return SRTP_AEAD_AES_128_GCM;
+  if (crypto_suite == CS_AEAD_AES_256_GCM)
+    return SRTP_AEAD_AES_256_GCM;
   return SRTP_INVALID_CRYPTO_SUITE;
 }
 
+bool GetSrtpKeyAndSaltLengths(int crypto_suite, int *key_length,
+    int *salt_length) {
+  switch (crypto_suite) {
+  case SRTP_AES128_CM_SHA1_32:
+  case SRTP_AES128_CM_SHA1_80:
+    *key_length = 16;
+    *salt_length = 14;
+    break;
+  case SRTP_AEAD_AES_128_GCM:
+    *key_length = 16;
+    *salt_length = 12;
+    break;
+  case SRTP_AEAD_AES_256_GCM:
+    *key_length = 32;
+    *salt_length = 12;

[pthatcher1, 2016/01/30 00:54:33]

Can you leave a comment saying where these values come from?

[joachim, 2016/01/31 23:39:52]

Done.

+    break;
+  default:
+    return false;
+  }
+  return true;
+}
+
+bool IsGcmCryptoSuite(int crypto_suite) {
+  return (crypto_suite == SRTP_AEAD_AES_256_GCM ||
+          crypto_suite == SRTP_AEAD_AES_128_GCM);
+}
+
+bool IsGcmCryptoSuiteName(const std::string& crypto_suite) {
+  return (crypto_suite == CS_AEAD_AES_256_GCM ||
+          crypto_suite == CS_AEAD_AES_128_GCM);
+}
+
+
 SSLStreamAdapter* SSLStreamAdapter::Create(StreamInterface* stream) {
 #if SSL_USE_OPENSSL
   return new OpenSSLStreamAdapter(stream);
 #else  // !SSL_USE_OPENSSL
   return NULL;
 #endif  // SSL_USE_OPENSSL
 }
 
 bool SSLStreamAdapter::GetSslCipherSuite(int* cipher_suite) {
   return false;
@@ skipping 33 matching lines @@
 }
 
 std::string SSLStreamAdapter::SslCipherSuiteToName(int cipher_suite) {
   return OpenSSLStreamAdapter::SslCipherSuiteToName(cipher_suite);
 }
 #endif  // SSL_USE_OPENSSL
 
 ///////////////////////////////////////////////////////////////////////////////
 
 }  // namespace rtc