int janus_dtls_srtp_create_sctp(janus_dtls_srtp *dtls) {
#ifdef HAVE_SCTP
if(dtls == NULL)
return -1;
janus_ice_component *component = (janus_ice_component *)dtls->component;
if(component == NULL)
return -2;
janus_ice_stream *stream = component->stream;
if(!stream)
return -3;
janus_ice_handle *handle = stream->handle;
if(!handle || !handle->agent)
return -4;
if(janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_ALERT))
return -5;
dtls->sctp = janus_sctp_association_create(dtls, handle->handle_id, 5000);
if(dtls->sctp == NULL) {
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Error creating SCTP association...\n", handle->handle_id);
return -6;
}
/* We need to start it in a thread, since it has blocking accept/connect stuff */
janus_refcount_increase(&dtls->ref);
janus_refcount_increase(&dtls->sctp->ref);
GError *error = NULL;
char tname[16];
g_snprintf(tname, sizeof(tname), "sctpinit %"SCNu64, handle->handle_id);
g_thread_try_new(tname, janus_dtls_sctp_setup_thread, dtls, &error);
if(error != NULL) {
/* Something went wrong... */
janus_refcount_decrease(&dtls->ref);
janus_refcount_decrease(&dtls->sctp->ref);
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Got error %d (%s) trying to launch the DTLS-SCTP thread...\n", handle->handle_id, error->code, error->message ? error->message : "??");
return -7;
}
return 0;
#else
/* Support for datachannels hasn't been built in */
return -1;
#endif
}
void janus_dtls_srtp_incoming_msg(janus_dtls_srtp *dtls, char *buf, uint16_t len) {
if(dtls == NULL) {
JANUS_LOG(LOG_ERR, "No DTLS-SRTP stack, no incoming message...\n");
return;
}
janus_ice_component *component = (janus_ice_component *)dtls->component;
if(component == NULL) {
JANUS_LOG(LOG_ERR, "No component, no DTLS...\n");
return;
}
janus_ice_stream *stream = component->stream;
if(!stream) {
JANUS_LOG(LOG_ERR, "No stream, no DTLS...\n");
return;
}
janus_ice_handle *handle = stream->handle;
if(!handle || !handle->agent) {
JANUS_LOG(LOG_ERR, "No handle/agent, no DTLS...\n");
return;
}
if(janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_ALERT)) {
JANUS_LOG(LOG_WARN, "[%"SCNu64"] Alert already triggered, clearing up...\n", handle->handle_id);
return;
}
if(!dtls->ssl || !dtls->read_bio) {
JANUS_LOG(LOG_ERR, "[%"SCNu64"] No DTLS stuff for component %d in stream %d??\n", handle->handle_id, component->component_id, stream->stream_id);
return;
}
janus_dtls_fd_bridge(dtls);
int written = BIO_write(dtls->read_bio, buf, len);
JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Written %d of those bytes on the read BIO...\n", handle->handle_id, written);
janus_dtls_fd_bridge(dtls);
/* Try to read data */
char data[1500]; /* FIXME */
memset(&data, 0, 1500);
int read = SSL_read(dtls->ssl, &data, 1500);
JANUS_LOG(LOG_HUGE, "[%"SCNu64"] ... and read %d of them from SSL...\n", handle->handle_id, read);
if(read < 0) {
unsigned long err = SSL_get_error(dtls->ssl, read);
if(err == SSL_ERROR_SSL) {
/* Ops, something went wrong with the DTLS handshake */
char error[200];
ERR_error_string_n(ERR_get_error(), error, 200);
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Handshake error: %s\n", handle->handle_id, error);
return;
}
}
janus_dtls_fd_bridge(dtls);
if(janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_STOP) || janus_is_stopping()) {
/* DTLS alert triggered, we should end it here */
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Forced to stop it here...\n", handle->handle_id);
return;
}
if(!SSL_is_init_finished(dtls->ssl)) {
/* Nothing else to do for now */
JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Initialization not finished yet...\n", handle->handle_id);
return;
}
if(dtls->ready) {
/* There's data to be read? */
JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Any data available?\n", handle->handle_id);
#ifdef HAVE_SCTP
if(dtls->sctp != NULL && read > 0) {
JANUS_LOG(LOG_HUGE, "[%"SCNu64"] Sending data (%d bytes) to the SCTP stack...\n", handle->handle_id, read);
janus_sctp_data_from_dtls(dtls->sctp, data, read);
}
#else
if(read > 0) {
JANUS_LOG(LOG_WARN, "[%"SCNu64"] Data available but Data Channels support disabled...\n", handle->handle_id);
}
#endif
} else {
JANUS_LOG(LOG_VERB, "[%"SCNu64"] DTLS established, yay!\n", handle->handle_id);
/* Check the remote fingerprint */
X509 *rcert = SSL_get_peer_certificate(dtls->ssl);
if(!rcert) {
JANUS_LOG(LOG_ERR, "[%"SCNu64"] No remote certificate??\n", handle->handle_id);
} else {
unsigned int rsize;
unsigned char rfingerprint[EVP_MAX_MD_SIZE];
char remote_fingerprint[160];
char *rfp = (char *)&remote_fingerprint;
if(handle->remote_hashing && !strcasecmp(handle->remote_hashing, "sha-1")) {
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Computing sha-1 fingerprint of remote certificate...\n", handle->handle_id);
X509_digest(rcert, EVP_sha1(), (unsigned char *)rfingerprint, &rsize);
} else {
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Computing sha-256 fingerprint of remote certificate...\n", handle->handle_id);
X509_digest(rcert, EVP_sha256(), (unsigned char *)rfingerprint, &rsize);
}
X509_free(rcert);
rcert = NULL;
unsigned int i = 0;
for(i = 0; i < rsize; i++) {
g_snprintf(rfp, 4, "%.2X:", rfingerprint[i]);
rfp += 3;
}
*(rfp-1) = 0;
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Remote fingerprint (%s) of the client is %s\n",
handle->handle_id, handle->remote_hashing ? handle->remote_hashing : "sha-256", remote_fingerprint);
if(!strcasecmp(remote_fingerprint, handle->remote_fingerprint ? handle->remote_fingerprint : "(none)")) {
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Fingerprint is a match!\n", handle->handle_id);
dtls->dtls_state = JANUS_DTLS_STATE_CONNECTED;
dtls->dtls_connected = janus_get_monotonic_time();
} else {
/* FIXME NOT a match! MITM? */
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Fingerprint is NOT a match! got %s, expected %s\n", handle->handle_id, remote_fingerprint, handle->remote_fingerprint);
dtls->dtls_state = JANUS_DTLS_STATE_FAILED;
goto done;
}
if(dtls->dtls_state == JANUS_DTLS_STATE_CONNECTED) {
if(component->stream_id == handle->audio_id || component->stream_id == handle->video_id) {
/* Complete with SRTP setup */
unsigned char material[SRTP_MASTER_LENGTH*2];
unsigned char *local_key, *local_salt, *remote_key, *remote_salt;
/* Export keying material for SRTP */
if (!SSL_export_keying_material(dtls->ssl, material, SRTP_MASTER_LENGTH*2, "EXTRACTOR-dtls_srtp", 19, NULL, 0, 0)) {
/* Oops... */
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Oops, couldn't extract SRTP keying material for component %d in stream %d??\n", handle->handle_id, component->component_id, stream->stream_id);
goto done;
}
/* Key derivation (http://tools.ietf.org/html/rfc5764#section-4.2) */
if(dtls->dtls_role == JANUS_DTLS_ROLE_CLIENT) {
local_key = material;
remote_key = local_key + SRTP_MASTER_KEY_LENGTH;
local_salt = remote_key + SRTP_MASTER_KEY_LENGTH;
remote_salt = local_salt + SRTP_MASTER_SALT_LENGTH;
} else {
remote_key = material;
local_key = remote_key + SRTP_MASTER_KEY_LENGTH;
remote_salt = local_key + SRTP_MASTER_KEY_LENGTH;
local_salt = remote_salt + SRTP_MASTER_SALT_LENGTH;
}
/* Build master keys and set SRTP policies */
/* Remote (inbound) */
crypto_policy_set_rtp_default(&(dtls->remote_policy.rtp));
crypto_policy_set_rtcp_default(&(dtls->remote_policy.rtcp));
dtls->remote_policy.ssrc.type = ssrc_any_inbound;
unsigned char remote_policy_key[SRTP_MASTER_LENGTH];
dtls->remote_policy.key = (unsigned char *)&remote_policy_key;
memcpy(dtls->remote_policy.key, remote_key, SRTP_MASTER_KEY_LENGTH);
memcpy(dtls->remote_policy.key + SRTP_MASTER_KEY_LENGTH, remote_salt, SRTP_MASTER_SALT_LENGTH);
#if HAS_DTLS_WINDOW_SIZE
dtls->remote_policy.window_size = 128;
dtls->remote_policy.allow_repeat_tx = 0;
#endif
dtls->remote_policy.next = NULL;
/* Local (outbound) */
crypto_policy_set_rtp_default(&(dtls->local_policy.rtp));
crypto_policy_set_rtcp_default(&(dtls->local_policy.rtcp));
dtls->local_policy.ssrc.type = ssrc_any_outbound;
unsigned char local_policy_key[SRTP_MASTER_LENGTH];
dtls->local_policy.key = (unsigned char *)&local_policy_key;
memcpy(dtls->local_policy.key, local_key, SRTP_MASTER_KEY_LENGTH);
memcpy(dtls->local_policy.key + SRTP_MASTER_KEY_LENGTH, local_salt, SRTP_MASTER_SALT_LENGTH);
#if HAS_DTLS_WINDOW_SIZE
dtls->local_policy.window_size = 128;
dtls->local_policy.allow_repeat_tx = 0;
#endif
dtls->local_policy.next = NULL;
/* Create SRTP sessions */
err_status_t res = srtp_create(&(dtls->srtp_in), &(dtls->remote_policy));
if(res != err_status_ok) {
/* Something went wrong... */
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Oops, error creating inbound SRTP session for component %d in stream %d??\n", handle->handle_id, component->component_id, stream->stream_id);
JANUS_LOG(LOG_ERR, "[%"SCNu64"] -- %d (%s)\n", handle->handle_id, res, janus_get_srtp_error(res));
goto done;
}
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Created inbound SRTP session for component %d in stream %d\n", handle->handle_id, component->component_id, stream->stream_id);
res = srtp_create(&(dtls->srtp_out), &(dtls->local_policy));
if(res != err_status_ok) {
/* Something went wrong... */
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Oops, error creating outbound SRTP session for component %d in stream %d??\n", handle->handle_id, component->component_id, stream->stream_id);
JANUS_LOG(LOG_ERR, "[%"SCNu64"] -- %d (%s)\n", handle->handle_id, res, janus_get_srtp_error(res));
goto done;
}
dtls->srtp_valid = 1;
JANUS_LOG(LOG_VERB, "[%"SCNu64"] Created outbound SRTP session for component %d in stream %d\n", handle->handle_id, component->component_id, stream->stream_id);
}
#ifdef HAVE_SCTP
if(component->stream_id == handle->data_id ||
(janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_BUNDLE) &&
janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_DATA_CHANNELS))) {
/* FIXME Create SCTP association as well (5000 should be dynamic, from the SDP...) */
dtls->sctp = janus_sctp_association_create(dtls, handle->handle_id, 5000);
if(dtls->sctp != NULL) {
/* FIXME We need to start it in a thread, though, since it has blocking accept/connect stuff */
GError *error = NULL;
g_thread_try_new("DTLS-SCTP", janus_dtls_sctp_setup_thread, dtls, &error);
if(error != NULL) {
/* Something went wrong... */
JANUS_LOG(LOG_ERR, "[%"SCNu64"] Got error %d (%s) trying to launch the DTLS-SCTP thread...\n", handle->handle_id, error->code, error->message ? error->message : "??");
}
dtls->srtp_valid = 1;
}
}
#endif
dtls->ready = 1;
}
done:
if(!janus_flags_is_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_ALERT) && dtls->srtp_valid) {
/* Handshake successfully completed */
janus_ice_dtls_handshake_done(handle, component);
} else {
/* Something went wrong in either DTLS or SRTP... tell the plugin about it */
janus_dtls_callback(dtls->ssl, SSL_CB_ALERT, 0);
janus_flags_set(&handle->webrtc_flags, JANUS_ICE_HANDLE_WEBRTC_CLEANING);
}
}
}
}
