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230 lines
6.4 KiB
230 lines
6.4 KiB
/*
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* rtp.c
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*
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* library functions for the real-time transport protocol
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*
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* David A. McGrew
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* Cisco Systems, Inc.
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*/
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/*
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*
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* Copyright (c) 2001-2017, Cisco Systems, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "rtp.h"
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#ifdef HAVE_SYS_SOCKET_H
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#include <sys/socket.h>
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#endif
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#include "cipher_priv.h"
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#define PRINT_DEBUG 0 /* set to 1 to print out debugging data */
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#define VERBOSE_DEBUG 0 /* set to 1 to print out more data */
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int rtp_sendto(rtp_sender_t sender, const void *msg, int len)
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{
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int octets_sent;
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srtp_err_status_t stat;
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int pkt_len = len + RTP_HEADER_LEN;
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/* marshal data */
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strncpy(sender->message.body, msg, len);
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/* update header */
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sender->message.header.seq = ntohs(sender->message.header.seq) + 1;
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sender->message.header.seq = htons(sender->message.header.seq);
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sender->message.header.ts = ntohl(sender->message.header.ts) + 1;
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sender->message.header.ts = htonl(sender->message.header.ts);
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/* apply srtp */
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stat = srtp_protect(sender->srtp_ctx, &sender->message.header, &pkt_len);
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if (stat) {
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#if PRINT_DEBUG
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fprintf(stderr, "error: srtp protection failed with code %d\n", stat);
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#endif
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return -1;
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}
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#if VERBOSE_DEBUG
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srtp_print_packet(&sender->message.header, pkt_len);
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#endif
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octets_sent =
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sendto(sender->socket, (void *)&sender->message, pkt_len, 0,
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(struct sockaddr *)&sender->addr, sizeof(struct sockaddr_in));
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if (octets_sent != pkt_len) {
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#if PRINT_DEBUG
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fprintf(stderr, "error: couldn't send message %s", (char *)msg);
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perror("");
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#endif
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}
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return octets_sent;
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}
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int rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len)
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{
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int octets_recvd;
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srtp_err_status_t stat;
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octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message, *len,
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0, (struct sockaddr *)NULL, 0);
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if (octets_recvd == -1) {
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*len = 0;
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return -1;
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}
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/* verify rtp header */
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if (receiver->message.header.version != 2) {
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*len = 0;
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return -1;
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}
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#if PRINT_DEBUG
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fprintf(stderr, "%d octets received from SSRC %u\n", octets_recvd,
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receiver->message.header.ssrc);
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#endif
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#if VERBOSE_DEBUG
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srtp_print_packet(&receiver->message.header, octets_recvd);
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#endif
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/* apply srtp */
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stat = srtp_unprotect(receiver->srtp_ctx, &receiver->message.header,
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&octets_recvd);
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if (stat) {
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fprintf(stderr, "error: srtp unprotection failed with code %d%s\n",
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stat,
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stat == srtp_err_status_replay_fail
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? " (replay check failed)"
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: stat == srtp_err_status_auth_fail ? " (auth check failed)"
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: "");
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return -1;
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}
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strncpy(msg, receiver->message.body, octets_recvd);
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return octets_recvd;
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}
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int rtp_sender_init(rtp_sender_t sender,
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int sock,
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struct sockaddr_in addr,
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unsigned int ssrc)
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{
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/* set header values */
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sender->message.header.ssrc = htonl(ssrc);
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sender->message.header.ts = 0;
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sender->message.header.seq = (uint16_t)srtp_cipher_rand_u32_for_tests();
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sender->message.header.m = 0;
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sender->message.header.pt = 0x1;
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sender->message.header.version = 2;
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sender->message.header.p = 0;
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sender->message.header.x = 0;
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sender->message.header.cc = 0;
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/* set other stuff */
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sender->socket = sock;
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sender->addr = addr;
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return 0;
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}
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int rtp_receiver_init(rtp_receiver_t rcvr,
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int sock,
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struct sockaddr_in addr,
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unsigned int ssrc)
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{
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/* set header values */
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rcvr->message.header.ssrc = htonl(ssrc);
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rcvr->message.header.ts = 0;
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rcvr->message.header.seq = 0;
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rcvr->message.header.m = 0;
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rcvr->message.header.pt = 0x1;
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rcvr->message.header.version = 2;
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rcvr->message.header.p = 0;
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rcvr->message.header.x = 0;
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rcvr->message.header.cc = 0;
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/* set other stuff */
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rcvr->socket = sock;
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rcvr->addr = addr;
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return 0;
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}
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int rtp_sender_init_srtp(rtp_sender_t sender, const srtp_policy_t *policy)
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{
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return srtp_create(&sender->srtp_ctx, policy);
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}
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int rtp_sender_deinit_srtp(rtp_sender_t sender)
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{
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return srtp_dealloc(sender->srtp_ctx);
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}
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int rtp_receiver_init_srtp(rtp_receiver_t sender, const srtp_policy_t *policy)
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{
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return srtp_create(&sender->srtp_ctx, policy);
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}
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int rtp_receiver_deinit_srtp(rtp_receiver_t sender)
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{
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return srtp_dealloc(sender->srtp_ctx);
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}
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rtp_sender_t rtp_sender_alloc(void)
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{
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return (rtp_sender_t)malloc(sizeof(rtp_sender_ctx_t));
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}
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void rtp_sender_dealloc(rtp_sender_t rtp_ctx)
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{
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free(rtp_ctx);
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}
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rtp_receiver_t rtp_receiver_alloc(void)
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{
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return (rtp_receiver_t)malloc(sizeof(rtp_receiver_ctx_t));
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}
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void rtp_receiver_dealloc(rtp_receiver_t rtp_ctx)
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{
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free(rtp_ctx);
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}
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