diff options
Diffstat (limited to 'dom/media/webrtc/transport/SrtpFlow.cpp')
| -rw-r--r-- | dom/media/webrtc/transport/SrtpFlow.cpp | 259 |
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 |