diff options
Diffstat (limited to 'media/webrtc/signaling/src/mediapipeline/SrtpFlow.cpp')
| -rw-r--r-- | media/webrtc/signaling/src/mediapipeline/SrtpFlow.cpp | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/media/webrtc/signaling/src/mediapipeline/SrtpFlow.cpp b/media/webrtc/signaling/src/mediapipeline/SrtpFlow.cpp new file mode 100644 index 000000000..59c3dac0a --- /dev/null +++ b/media/webrtc/signaling/src/mediapipeline/SrtpFlow.cpp @@ -0,0 +1,251 @@ +/* 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 "ssl.h" +#include "sslproto.h" + +#include "mozilla/RefPtr.h" + +// Logging context +using namespace mozilla; +MOZ_MTLOG_MODULE("mediapipeline") + +namespace mozilla { + +bool SrtpFlow::initialized; // Static + +SrtpFlow::~SrtpFlow() { + if (session_) { + srtp_dealloc(session_); + } +} + +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_TOTAL_KEY_LENGTH) { + MOZ_MTLOG(ML_ERROR, "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 SRTP_AES128_CM_HMAC_SHA1_80: + MOZ_MTLOG(ML_DEBUG, + "Setting SRTP cipher suite SRTP_AES128_CM_HMAC_SHA1_80"); + crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp); + crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp); + break; + case SRTP_AES128_CM_HMAC_SHA1_32: + MOZ_MTLOG(ML_DEBUG, + "Setting SRTP cipher suite SRTP_AES128_CM_HMAC_SHA1_32"); + crypto_policy_set_aes_cm_128_hmac_sha1_32(&policy.rtp); + 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.ekt = nullptr; + 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 + err_status_t r = srtp_create(&flow->session_, &policy); + if (r != 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; + err_status_t r = srtp_protect(session_, in, &len); + + if (r != 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; + err_status_t r = srtp_unprotect(session_, in, &len); + + if (r != 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; + err_status_t r = srtp_protect_rtcp(session_, in, &len); + + if (r != 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; + err_status_t r = srtp_unprotect_rtcp(session_, in, &len); + + if (r != 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) { + err_status_t r = srtp_init(); + if (r != 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 != 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; +} + +} // end of namespace + |