/*
* rtp.c
*
* library functions for the real-time transport protocol
*
* David A. McGrew
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2001-2017, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "rtp.h"
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.h>
#endif
#define PRINT_DEBUG 0 /* set to 1 to print out debugging data */
#define VERBOSE_DEBUG 0 /* set to 1 to print out more data */
int
rtp_sendto(rtp_sender_t sender, const void* msg, int len) {
int octets_sent;
srtp_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;
}
int
rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len) {
int octets_recvd;
srtp_err_status_t stat;
octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message,
*len, 0, (struct sockaddr *) NULL, 0);
if (octets_recvd == -1) {
*len = 0;
return -1;
}
/* 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 == srtp_err_status_replay_fail ? " (replay check failed)" :
stat == srtp_err_status_auth_fail ? " (auth check failed)" : "");
return -1;
}
strncpy(msg, receiver->message.body, octets_recvd);
return octets_recvd;
}
int
rtp_sender_init(rtp_sender_t sender,
int sock,
struct sockaddr_in addr,
unsigned int ssrc) {
/* set header values */
sender->message.header.ssrc = htonl(ssrc);
sender->message.header.ts = 0;
sender->message.header.seq = (uint16_t) rand();
sender->message.header.m = 0;
sender->message.header.pt = 0x1;
sender->message.header.version = 2;
sender->message.header.p = 0;
sender->message.header.x = 0;
sender->message.header.cc = 0;
/* set other stuff */
sender->socket = sock;
sender->addr = addr;
return 0;
}
int
rtp_receiver_init(rtp_receiver_t rcvr,
int sock,
struct sockaddr_in addr,
unsigned int ssrc) {
/* set header values */
rcvr->message.header.ssrc = htonl(ssrc);
rcvr->message.header.ts = 0;
rcvr->message.header.seq = 0;
rcvr->message.header.m = 0;
rcvr->message.header.pt = 0x1;
rcvr->message.header.version = 2;
rcvr->message.header.p = 0;
rcvr->message.header.x = 0;
rcvr->message.header.cc = 0;
/* set other stuff */
rcvr->socket = sock;
rcvr->addr = addr;
return 0;
}
int
rtp_sender_init_srtp(rtp_sender_t sender, const srtp_policy_t *policy) {
return srtp_create(&sender->srtp_ctx, policy);
}
int
rtp_sender_deinit_srtp(rtp_sender_t sender) {
return srtp_dealloc(sender->srtp_ctx);
}
int
rtp_receiver_init_srtp(rtp_receiver_t sender, const srtp_policy_t *policy) {
return srtp_create(&sender->srtp_ctx, policy);
}
int
rtp_receiver_deinit_srtp(rtp_receiver_t sender) {
return srtp_dealloc(sender->srtp_ctx);
}
rtp_sender_t
rtp_sender_alloc(void) {
return (rtp_sender_t)malloc(sizeof(rtp_sender_ctx_t));
}
void
rtp_sender_dealloc(rtp_sender_t rtp_ctx) {
free(rtp_ctx);
}
rtp_receiver_t
rtp_receiver_alloc(void) {
return (rtp_receiver_t)malloc(sizeof(rtp_receiver_ctx_t));
}
void
rtp_receiver_dealloc(rtp_receiver_t rtp_ctx) {
free(rtp_ctx);
}