err_status_t
srtp_stream_init_from_ekt(srtp_stream_t stream,
const void *srtcp_hdr,
unsigned pkt_octet_len) {
err_status_t err;
const uint8_t *master_key;
srtp_policy_t srtp_policy;
unsigned master_key_len;
uint32_t roc;
/*
* NOTE: at present, we only support a single ekt_policy at a time.
*/
if (stream->ekt->data->spi !=
srtcp_packet_get_ekt_spi(srtcp_hdr, pkt_octet_len))
return err_status_no_ctx;
if (stream->ekt->data->ekt_cipher_type != EKT_CIPHER_AES_128_ECB)
return err_status_bad_param;
master_key_len = 16;
/* decrypt the Encrypted Master Key field */
master_key = srtcp_packet_get_emk_location(srtcp_hdr, pkt_octet_len);
/* FIX!? This decrypts the master key in-place, and never uses it */
/* FIX!? It's also passing to ekt_dec_key (which is an AES_KEY)
* to a function which expects a raw (unexpanded) key */
aes_decrypt_with_raw_key((void*)master_key, &stream->ekt->data->ekt_dec_key, 16);
/* set the SRTP ROC */
roc = srtcp_packet_get_ekt_roc(srtcp_hdr, pkt_octet_len);
err = rdbx_set_roc(&stream->rtp_rdbx, roc);
if (err) return err;
err = srtp_stream_init(stream, &srtp_policy);
if (err) return err;
return err_status_ok;
}
/* Create a stream in the session
*/
static err_status_t
init_session_stream (GstSrtpDec * filter, guint32 ssrc,
GstSrtpDecSsrcStream * stream)
{
err_status_t ret;
srtp_policy_t policy;
GstMapInfo map;
guchar tmp[1];
memset (&policy, 0, sizeof (srtp_policy_t));
if (!stream)
return err_status_bad_param;
GST_INFO_OBJECT (filter, "Setting RTP policy...");
set_crypto_policy_cipher_auth (stream->rtp_cipher, stream->rtp_auth,
&policy.rtp);
GST_INFO_OBJECT (filter, "Setting RTCP policy...");
set_crypto_policy_cipher_auth (stream->rtcp_cipher, stream->rtcp_auth,
&policy.rtcp);
if (stream->key) {
gst_buffer_map (stream->key, &map, GST_MAP_READ);
policy.key = (guchar *) map.data;
} else {
policy.key = tmp;
}
policy.ssrc.value = ssrc;
policy.ssrc.type = ssrc_specific;
policy.window_size = filter->replay_window_size;
policy.next = NULL;
/* If it is the first stream, create the session
* If not, add the stream policy to the session
*/
if (filter->first_session)
ret = srtp_create (&filter->session, &policy);
else
ret = srtp_add_stream (filter->session, &policy);
if (stream->key)
gst_buffer_unmap (stream->key, &map);
if (ret == err_status_ok) {
srtp_stream_t srtp_stream;
srtp_stream = srtp_get_stream (filter->session, htonl (ssrc));
if (srtp_stream) {
/* Here, we just set the ROC, but we also need to set the initial
* RTP sequence number later, otherwise libsrtp will not be able
* to get the right packet index. */
rdbx_set_roc (&srtp_stream->rtp_rdbx, stream->roc);
filter->roc_changed = TRUE;
}
filter->first_session = FALSE;
g_hash_table_insert (filter->streams, GUINT_TO_POINTER (stream->ssrc),
stream);
}
return ret;
}
