static int srtp_recvfrom(RtpTransport *t, mblk_t *m, int flags, struct sockaddr *from, socklen_t *fromlen){
srtp_t srtp=(srtp_t)t->data;
int err;
int slen;
err=rtp_session_rtp_recv_abstract(t->session->rtp.socket,m,flags,from,fromlen);
if (err>0){
err_status_t srtp_err;
/* keep NON-RTP data unencrypted */
rtp_header_t *rtp;
if (err>=RTP_FIXED_HEADER_SIZE)
{
rtp = (rtp_header_t*)m->b_wptr;
if (rtp->version!=2)
{
return err;
}
}
slen=err;
srtp_err = srtp_unprotect(srtp,m->b_wptr,&slen);
if (srtp_err==err_status_ok)
return slen;
else {
ortp_error("srtp_unprotect() failed (%d)", srtp_err);
return -1;
}
}
return err;
}
static int srtcp_recvfrom(RtpTransport *t, mblk_t *m, int flags, struct sockaddr *from, socklen_t *fromlen){
srtp_t srtp=(srtp_t)t->data;
int err;
int slen;
err=rtp_session_rtp_recv_abstract(t->session->rtcp.socket,m,flags,from,fromlen);
if (err>0){
err_status_t srtp_err;
slen=err;
srtp_err=srtp_unprotect_rtcp(srtp,m->b_wptr,&slen);
if (srtp_err==err_status_ok)
return slen;
else {
ortp_error("srtp_unprotect_rtcp() failed (%d)", srtp_err);
return -1;
}
}
return err;
}
static int ozrtp_rtcp_recvfrom(RtpTransport *t, mblk_t *m, int flags, struct sockaddr *from, socklen_t *fromlen){
ZrtpContext *zrtpContext = (ZrtpContext*) t->data;
OrtpZrtpContext *userData = (OrtpZrtpContext*) zrtpContext->userData;
int rlen = rtp_session_rtp_recv_abstract(t->session->rtcp.socket,m,flags,from,fromlen);
if (rlen<=0) {
// nothing was received or error: pass the information to caller
return rlen;
}
if (userData->srtpRecv != NULL && zrtp_inState(zrtpContext, SecureState)) {
err_status_t err = srtp_unprotect_rtcp(userData->srtpRecv,m->b_wptr,&rlen);
if (err != err_status_ok) {
ortp_error("srtp_unprotect failed %d ; packet discarded (may be plain RTCP)", err);
return 0;
}
}
return rlen;
}
static int ozrtp_rtp_recvfrom(RtpTransport *t, mblk_t *m, int flags, struct sockaddr *from, socklen_t *fromlen){
int rlen;
ZrtpContext *zrtpContext = (ZrtpContext*) t->data;
OrtpZrtpContext *userData = (OrtpZrtpContext*) zrtpContext->userData;
// Do extra stuff first
check_timer(zrtpContext, userData);
// Check if something to receive
rlen=rtp_session_rtp_recv_abstract(t->session->rtp.socket,m,flags,from,fromlen);
if (rlen<=0) {
// nothing was received or error: pass the information to caller
return rlen;
}
uint8_t* rtp = m->b_rptr;
int rtpVersion = ((rtp_header_t*)rtp)->version;
// If plain or secured RTP
if (rtpVersion == 2) {
if (userData->srtpRecv != NULL && zrtp_inState(zrtpContext, SecureState)) {
// probably srtp packet, unprotect
err_status_t err = srtp_unprotect(userData->srtpRecv,m->b_wptr,&rlen);
if (err != err_status_ok) {
ortp_warning("srtp_unprotect failed; packet may be plain RTP");
}
}
// in both cases (RTP plain and deciphered srtp)
return rlen;
}
// if ZRTP packet, send to engine
uint32_t *magicField=(uint32_t *)(rtp + 4);
if (rlen >= ZRTP_MIN_MSG_LENGTH && rtpVersion==0 && ntohl(*magicField) == ZRTP_MAGIC) {
print_zrtp_packet("received", rtp);
uint8_t *ext_header = rtp+ZRTP_MESSAGE_OFFSET;
uint16_t ext_length = get_zrtp_message_length(ext_header);
char messageType[9];
parseZrtpMessageType(messageType, ext_header);
// Check max length
if (rlen < 12 + ext_length + 4) {
ortp_warning("Received malformed ZRTP-like packet: size %d (expected %d)", rlen, 12 + ext_length + 4);
return 0;
}
// Check sequence number
uint16_t seq_number = get_rtp_seqnumber(rtp);
if (userData->last_recv_zrtp_seq_number != 0 && seq_number <= userData->last_recv_zrtp_seq_number) {
// Discard out of order ZRTP packet
ortp_message("Discarding received out of order zrtp packet: %d (expected >%d)",
seq_number, userData->last_recv_zrtp_seq_number);
return 0;
}
// Check packet checksum
uint32_t rcv_crc = get_zrtp_packet_crc((uint32_t*)rtp, ext_length);
uint32_t zrtp_total_packet_length = ZRTP_MESSAGE_OFFSET + 4*ext_length + 4;
if (!zrtp_CheckCksum(rtp, zrtp_total_packet_length-CRC_SIZE, rcv_crc)) {
ortp_warning("Bad ZRTP packet checksum %u total %u", rcv_crc, zrtp_total_packet_length);
return 0;
}
uint32_t peerssrc = ntohl(*(uint32_t*)(rtp+8));
#if HAVE_zrtpcpp_with_len
zrtp_processZrtpMessage(zrtpContext, ext_header, peerssrc,rlen);
#else
zrtp_processZrtpMessage(zrtpContext, ext_header, peerssrc);
#endif
userData->last_recv_zrtp_seq_number=seq_number;
return 0;
}
else {
// Not a ZRTP packet, accept it
return rlen;
}
}
