OpalRTPSession::SendReceiveStatus OpalDTLSSRTPSession::ExecuteHandshake(Channel channel)
{
{
PWaitAndSignal mutex(m_dataMutex);
if (m_remotePort[channel] == 0)
return e_IgnorePacket; // Too early
if (m_sslChannel[channel] == NULL)
return e_ProcessPacket; // Too late (done)
}
SSLChannel & sslChannel = *m_sslChannel[channel];
if (!sslChannel.ExecuteHandshake())
return e_AbortTransport;
const OpalMediaCryptoSuite* cryptoSuite = NULL;
srtp_profile_t profile = srtp_profile_reserved;
for (PINDEX i = 0; i < PARRAYSIZE(ProfileNames); ++i) {
if (sslChannel.GetSelectedProfile() == ProfileNames[i].m_dtlsName) {
profile = ProfileNames[i].m_profile;
cryptoSuite = OpalMediaCryptoSuiteFactory::CreateInstance(ProfileNames[i].m_opalName);
break;
}
}
if (profile == srtp_profile_reserved || cryptoSuite == NULL) {
PTRACE(2, "Error in SRTP profile.");
return e_AbortTransport;
}
PINDEX masterKeyLength = srtp_profile_get_master_key_length(profile);
PINDEX masterSaltLength = srtp_profile_get_master_salt_length(profile);
PBYTEArray keyMaterial = sslChannel.GetKeyMaterial(((masterSaltLength + masterKeyLength) << 1), "EXTRACTOR-dtls_srtp");
if (keyMaterial.IsEmpty())
return e_AbortTransport;
OpalSRTPKeyInfo * keyInfo = dynamic_cast<OpalSRTPKeyInfo*>(cryptoSuite->CreateKeyInfo());
PAssertNULL(keyInfo);
keyInfo->SetCipherKey(PBYTEArray(keyMaterial, masterKeyLength));
keyInfo->SetAuthSalt(PBYTEArray(keyMaterial + masterKeyLength*2, masterSaltLength));
ApplyKeyToSRTP(*keyInfo, sslChannel.IsServer() ? e_Receiver : e_Sender);
keyInfo->SetCipherKey(PBYTEArray(keyMaterial + masterKeyLength, masterKeyLength));
keyInfo->SetAuthSalt(PBYTEArray(keyMaterial + masterKeyLength*2 + masterSaltLength, masterSaltLength));
ApplyKeyToSRTP(*keyInfo, sslChannel.IsServer() ? e_Sender : e_Receiver);
delete keyInfo;
m_queueChannel[channel].Close();
sslChannel.Detach(PChannel::ShutdownWrite); // Do not close the socket!
delete m_sslChannel[channel];
m_sslChannel[channel] = NULL;
return e_ProcessPacket;
}
srtp_err_status_t
test_dtls_srtp(void) {
srtp_hdr_t *test_packet;
int test_packet_len = 80;
srtp_t s;
srtp_policy_t policy;
uint8_t key[SRTP_MAX_KEY_LEN];
uint8_t salt[SRTP_MAX_KEY_LEN];
unsigned int key_len, salt_len;
srtp_profile_t profile;
srtp_err_status_t err;
/* create a 'null' SRTP session */
err = srtp_create(&s, NULL);
if (err)
return err;
/*
* verify that packet-processing functions behave properly - we
* expect that these functions will return srtp_err_status_no_ctx
*/
test_packet = srtp_create_test_packet(80, 0xa5a5a5a5);
if (test_packet == NULL)
return srtp_err_status_alloc_fail;
err = srtp_protect(s, test_packet, &test_packet_len);
if (err != srtp_err_status_no_ctx) {
printf("wrong return value from srtp_protect() (got code %d)\n",
err);
return srtp_err_status_fail;
}
err = srtp_unprotect(s, test_packet, &test_packet_len);
if (err != srtp_err_status_no_ctx) {
printf("wrong return value from srtp_unprotect() (got code %d)\n",
err);
return srtp_err_status_fail;
}
err = srtp_protect_rtcp(s, test_packet, &test_packet_len);
if (err != srtp_err_status_no_ctx) {
printf("wrong return value from srtp_protect_rtcp() (got code %d)\n",
err);
return srtp_err_status_fail;
}
err = srtp_unprotect_rtcp(s, test_packet, &test_packet_len);
if (err != srtp_err_status_no_ctx) {
printf("wrong return value from srtp_unprotect_rtcp() (got code %d)\n",
err);
return srtp_err_status_fail;
}
/*
* set keys to known values for testing
*/
profile = srtp_profile_aes128_cm_sha1_80;
key_len = srtp_profile_get_master_key_length(profile);
salt_len = srtp_profile_get_master_salt_length(profile);
memset(key, 0xff, key_len);
memset(salt, 0xee, salt_len);
srtp_append_salt_to_key(key, key_len, salt, salt_len);
policy.key = key;
/* initialize SRTP policy from profile */
err = srtp_crypto_policy_set_from_profile_for_rtp(&policy.rtp, profile);
if (err) return err;
err = srtp_crypto_policy_set_from_profile_for_rtcp(&policy.rtcp, profile);
if (err) return err;
policy.ssrc.type = ssrc_any_inbound;
policy.ekt = NULL;
policy.window_size = 128;
policy.allow_repeat_tx = 0;
policy.next = NULL;
err = srtp_add_stream(s, &policy);
if (err)
return err;
err = srtp_dealloc(s);
if (err)
return err;
free(test_packet);
return srtp_err_status_ok;
}
