151 lines
3.6 KiB
C
151 lines
3.6 KiB
C
/*
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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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#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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#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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ssize_t
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rtp_sendto(rtp_sender_t *sender, const void* msg, int len) {
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int octets_sent;
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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 = sendto(sender->socket, (void*)&sender->message,
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pkt_len, 0, (struct sockaddr *)&sender->addr,
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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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ssize_t
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rtp_recvfrom(rtp_receiver_t *receiver, void *msg, int *len) {
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int octets_recvd;
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err_status_t stat;
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octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message,
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*len, 0, (struct sockaddr *) NULL, 0);
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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",
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octets_recvd, 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,
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&receiver->message.header, &octets_recvd);
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if (stat) {
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fprintf(stderr,
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"error: srtp unprotection failed with code %d%s\n", stat,
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stat == err_status_replay_fail ? " (replay check failed)" :
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stat == err_status_auth_fail ? " (auth check failed)" : "");
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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
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rtp_sender_init(rtp_sender_t *sender,
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int socket,
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struct sockaddr_in addr,
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uint32_t ssrc) {
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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) rand();
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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 = socket;
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sender->addr = addr;
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return 0;
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}
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int
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rtp_receiver_init(rtp_receiver_t *rcvr,
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int socket,
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struct sockaddr_in addr,
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uint32_t ssrc) {
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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 = socket;
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rcvr->addr = addr;
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return 0;
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}
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