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-rw-r--r--dom/media/webrtc/transport/SrtpFlow.cpp259
1 files changed, 259 insertions, 0 deletions
diff --git a/dom/media/webrtc/transport/SrtpFlow.cpp b/dom/media/webrtc/transport/SrtpFlow.cpp
new file mode 100644
index 0000000000..827d1a0f6d
--- /dev/null
+++ b/dom/media/webrtc/transport/SrtpFlow.cpp
@@ -0,0 +1,259 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Original author: ekr@rtfm.com
+
+#include "logging.h"
+#include "SrtpFlow.h"
+
+#include "srtp.h"
+
+#include "transportlayerdtls.h"
+
+#include "mozilla/RefPtr.h"
+
+using namespace mozilla;
+
+namespace mozilla {
+
+MOZ_MTLOG_MODULE("mtransport")
+bool SrtpFlow::initialized; // Static
+
+SrtpFlow::~SrtpFlow() {
+ if (session_) {
+ srtp_dealloc(session_);
+ }
+}
+
+unsigned int SrtpFlow::KeySize(int cipher_suite) {
+ srtp_profile_t profile = static_cast<srtp_profile_t>(cipher_suite);
+ return srtp_profile_get_master_key_length(profile);
+}
+
+unsigned int SrtpFlow::SaltSize(int cipher_suite) {
+ srtp_profile_t profile = static_cast<srtp_profile_t>(cipher_suite);
+ return srtp_profile_get_master_salt_length(profile);
+}
+
+RefPtr<SrtpFlow> SrtpFlow::Create(int cipher_suite, bool inbound,
+ const void* key, size_t key_len) {
+ nsresult res = Init();
+ if (!NS_SUCCEEDED(res)) return nullptr;
+
+ RefPtr<SrtpFlow> flow = new SrtpFlow();
+
+ if (!key) {
+ MOZ_MTLOG(ML_ERROR, "Null SRTP key specified");
+ return nullptr;
+ }
+
+ if ((key_len > SRTP_MAX_KEY_LENGTH) || (key_len < SRTP_MIN_KEY_LENGTH)) {
+ MOZ_ASSERT(false, "Invalid SRTP key length");
+ return nullptr;
+ }
+
+ srtp_policy_t policy;
+ memset(&policy, 0, sizeof(srtp_policy_t));
+
+ // Note that we set the same cipher suite for RTP and RTCP
+ // since any flow can only have one cipher suite with DTLS-SRTP
+ switch (cipher_suite) {
+ case kDtlsSrtpAeadAes256Gcm:
+ MOZ_MTLOG(ML_DEBUG, "Setting SRTP cipher suite SRTP_AEAD_AES_256_GCM");
+ srtp_crypto_policy_set_aes_gcm_256_16_auth(&policy.rtp);
+ srtp_crypto_policy_set_aes_gcm_256_16_auth(&policy.rtcp);
+ break;
+ case kDtlsSrtpAeadAes128Gcm:
+ MOZ_MTLOG(ML_DEBUG, "Setting SRTP cipher suite SRTP_AEAD_AES_128_GCM");
+ srtp_crypto_policy_set_aes_gcm_128_16_auth(&policy.rtp);
+ srtp_crypto_policy_set_aes_gcm_128_16_auth(&policy.rtcp);
+ break;
+ case kDtlsSrtpAes128CmHmacSha1_80:
+ MOZ_MTLOG(ML_DEBUG,
+ "Setting SRTP cipher suite SRTP_AES128_CM_HMAC_SHA1_80");
+ srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp);
+ srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp);
+ break;
+ case kDtlsSrtpAes128CmHmacSha1_32:
+ MOZ_MTLOG(ML_DEBUG,
+ "Setting SRTP cipher suite SRTP_AES128_CM_HMAC_SHA1_32");
+ srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32(&policy.rtp);
+ srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(
+ &policy.rtcp); // 80-bit per RFC 5764
+ break; // S 4.1.2.
+ default:
+ MOZ_MTLOG(ML_ERROR, "Request to set unknown SRTP cipher suite");
+ return nullptr;
+ }
+ // This key is copied into the srtp_t object, so we don't
+ // need to keep it.
+ policy.key =
+ const_cast<unsigned char*>(static_cast<const unsigned char*>(key));
+ policy.ssrc.type = inbound ? ssrc_any_inbound : ssrc_any_outbound;
+ policy.ssrc.value = 0;
+ policy.window_size =
+ 1024; // Use the Chrome value. Needs to be revisited. Default is 128
+ policy.allow_repeat_tx = 1; // Use Chrome value; needed for NACK mode to work
+ policy.next = nullptr;
+
+ // Now make the session
+ srtp_err_status_t r = srtp_create(&flow->session_, &policy);
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Error creating srtp session");
+ return nullptr;
+ }
+
+ return flow;
+}
+
+nsresult SrtpFlow::CheckInputs(bool protect, void* in, int in_len, int max_len,
+ int* out_len) {
+ MOZ_ASSERT(in);
+ if (!in) {
+ MOZ_MTLOG(ML_ERROR, "NULL input value");
+ return NS_ERROR_NULL_POINTER;
+ }
+
+ if (in_len < 0) {
+ MOZ_MTLOG(ML_ERROR, "Input length is negative");
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ if (max_len < 0) {
+ MOZ_MTLOG(ML_ERROR, "Max output length is negative");
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ if (protect) {
+ if ((max_len < SRTP_MAX_EXPANSION) ||
+ ((max_len - SRTP_MAX_EXPANSION) < in_len)) {
+ MOZ_MTLOG(ML_ERROR, "Output too short");
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ } else {
+ if (in_len > max_len) {
+ MOZ_MTLOG(ML_ERROR, "Output too short");
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ }
+
+ return NS_OK;
+}
+
+nsresult SrtpFlow::ProtectRtp(void* in, int in_len, int max_len, int* out_len) {
+ nsresult res = CheckInputs(true, in, in_len, max_len, out_len);
+ if (NS_FAILED(res)) return res;
+
+ int len = in_len;
+ srtp_err_status_t r = srtp_protect(session_, in, &len);
+
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Error protecting SRTP packet");
+ return NS_ERROR_FAILURE;
+ }
+
+ MOZ_ASSERT(len <= max_len);
+ *out_len = len;
+
+ MOZ_MTLOG(ML_DEBUG,
+ "Successfully protected an SRTP packet of len " << *out_len);
+
+ return NS_OK;
+}
+
+nsresult SrtpFlow::UnprotectRtp(void* in, int in_len, int max_len,
+ int* out_len) {
+ nsresult res = CheckInputs(false, in, in_len, max_len, out_len);
+ if (NS_FAILED(res)) return res;
+
+ int len = in_len;
+ srtp_err_status_t r = srtp_unprotect(session_, in, &len);
+
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Error unprotecting SRTP packet error=" << (int)r);
+ return NS_ERROR_FAILURE;
+ }
+
+ MOZ_ASSERT(len <= max_len);
+ *out_len = len;
+
+ MOZ_MTLOG(ML_DEBUG,
+ "Successfully unprotected an SRTP packet of len " << *out_len);
+
+ return NS_OK;
+}
+
+nsresult SrtpFlow::ProtectRtcp(void* in, int in_len, int max_len,
+ int* out_len) {
+ nsresult res = CheckInputs(true, in, in_len, max_len, out_len);
+ if (NS_FAILED(res)) return res;
+
+ int len = in_len;
+ srtp_err_status_t r = srtp_protect_rtcp(session_, in, &len);
+
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Error protecting SRTCP packet");
+ return NS_ERROR_FAILURE;
+ }
+
+ MOZ_ASSERT(len <= max_len);
+ *out_len = len;
+
+ MOZ_MTLOG(ML_DEBUG,
+ "Successfully protected an SRTCP packet of len " << *out_len);
+
+ return NS_OK;
+}
+
+nsresult SrtpFlow::UnprotectRtcp(void* in, int in_len, int max_len,
+ int* out_len) {
+ nsresult res = CheckInputs(false, in, in_len, max_len, out_len);
+ if (NS_FAILED(res)) return res;
+
+ int len = in_len;
+ srtp_err_status_t r = srtp_unprotect_rtcp(session_, in, &len);
+
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Error unprotecting SRTCP packet error=" << (int)r);
+ return NS_ERROR_FAILURE;
+ }
+
+ MOZ_ASSERT(len <= max_len);
+ *out_len = len;
+
+ MOZ_MTLOG(ML_DEBUG,
+ "Successfully unprotected an SRTCP packet of len " << *out_len);
+
+ return NS_OK;
+}
+
+// Statics
+void SrtpFlow::srtp_event_handler(srtp_event_data_t* data) {
+ // TODO(ekr@rtfm.com): Implement this
+ MOZ_CRASH();
+}
+
+nsresult SrtpFlow::Init() {
+ if (!initialized) {
+ srtp_err_status_t r = srtp_init();
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Could not initialize SRTP");
+ MOZ_ASSERT(PR_FALSE);
+ return NS_ERROR_FAILURE;
+ }
+
+ r = srtp_install_event_handler(&SrtpFlow::srtp_event_handler);
+ if (r != srtp_err_status_ok) {
+ MOZ_MTLOG(ML_ERROR, "Could not install SRTP event handler");
+ MOZ_ASSERT(PR_FALSE);
+ return NS_ERROR_FAILURE;
+ }
+
+ initialized = true;
+ }
+
+ return NS_OK;
+}
+
+} // namespace mozilla