unsigned int rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len) {
int octets_recvd;
err_status_t stat;
octets_recvd = recvfrom(receiver->socket, (void *) &receiver->message,
*len, 0, (struct sockaddr *) NULL, 0);
/* verify rtp header */
if (receiver->message.header.version != 2) {
*len = 0;
return -1;
}
#if PRINT_DEBUG
fprintf(stderr, "%d octets received from SSRC %u\n",
octets_recvd, receiver->message.header.ssrc);
#endif
#if VERBOSE_DEBUG
srtp_print_packet(&receiver->message.header, octets_recvd);
#endif
/* apply srtp */
stat = srtp_unprotect(receiver->srtp_ctx, &receiver->message.header,
&octets_recvd);
if (stat) {
fprintf(stderr, "error: srtp unprotection failed with code %d%s\n",
stat, stat == err_status_replay_fail ? " (replay check failed)"
: stat == err_status_auth_fail ? " (auth check failed)"
: "");
return -1;
}
strncpy(msg, receiver->message.body, octets_recvd);
return octets_recvd;
}
int
rtp_sendto(rtp_sender_t sender, const void* msg, int len) {
int octets_sent;
err_status_t stat;
int pkt_len = len + RTP_HEADER_LEN;
/* marshal data */
strncpy(sender->message.body, msg, len);
/* update header */
sender->message.header.seq = ntohs(sender->message.header.seq) + 1;
sender->message.header.seq = htons(sender->message.header.seq);
sender->message.header.ts = ntohl(sender->message.header.ts) + 1;
sender->message.header.ts = htonl(sender->message.header.ts);
/* apply srtp */
stat = srtp_protect(sender->srtp_ctx, &sender->message.header, &pkt_len);
if (stat) {
#if PRINT_DEBUG
fprintf(stderr, "error: srtp protection failed with code %d\n", stat);
#endif
return -1;
}
#if VERBOSE_DEBUG
srtp_print_packet(&sender->message.header, pkt_len);
#endif
octets_sent = sendto(sender->socket, (void*)&sender->message,
pkt_len, 0, (struct sockaddr *)&sender->addr,
sizeof (struct sockaddr_in));
if (octets_sent != pkt_len) {
#if PRINT_DEBUG
fprintf(stderr, "error: couldn't send message %s", (char *)msg);
perror("");
#endif
}
return octets_sent;
}
