satip_rtp.c

/*
 * satip: RTP processing
 *
 * Copyright (C) 2014  mc.fishdish@gmail.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <poll.h>
#include <sched.h>

#include "satip_rtp.h"
#include "log.h"


#define PORT_BASE 45000
#define PORT_RANGE 2000


typedef struct satip_rtp
{
    int fd;
    int rtp_port;
    int rtp_socket;
    int rtcp_port;
    int rtcp_socket;
    pthread_t thread;
} t_satip_rtp;



static void rtp_data(unsigned char* buffer,int rx)
{
    int done=0;
    uint32_t* buf=(uint32_t*) buffer;
    uint32_t val;
    int plen;
    int pt;
    char* infobuf;

    while(done<rx)
    {
        val= ntohl(*buf);
        pt= ( val  & 0x00ff0000 ) >>16 ;
        plen= val & 0x0000ffff;

        switch(pt)
        {
        case 204:
            if (plen>1)
            {
                val=buf[2];
                DEBUG(MSG_MAIN,"RTCP: app defined (204) name: %c%c%c%c\n",
                      val & 0x000000ff,
                      val>>8 & 0x000000ff,
                      val>>16 & 0x000000ff,
                      val>>24 & 0x000000ff);

                val=htonl(buf[3]) & 0x0000ffff;
                if (val > 0)
                {
                    infobuf = (char*) malloc(val+1);
                    if (infobuf)
                    {
                        memcpy(infobuf, (char*) &buf[4], val);
                        infobuf[val]=0;
                        DEBUG(MSG_MAIN,"RTCP: app info: %s\n",infobuf);
                        free(infobuf);
                    }
                }
            }

            break;

        default:
            DEBUG(MSG_MAIN,"RTCP: packet type %d len %d\n",pt,plen);
        }

        buf+=plen+1;
        done+=(plen+1)*4;
    }
}


static void* rtp_receiver(void* param)
{
    unsigned char rxbuf[32768];
    struct pollfd pollfds[2];
    struct sched_param schedp;
    t_satip_rtp* srtp=(t_satip_rtp*)param;

    schedp.sched_priority = sched_get_priority_min(SCHED_FIFO)+1;

    if ( sched_setscheduler(0, SCHED_FIFO, &schedp) )
        DEBUG(MSG_MAIN,"RTP: No realtime scheduling\n");
    else
        DEBUG(MSG_MAIN,"RTP: Realtime scheduling enabled at prio %d\n",schedp.sched_priority);


    pollfds[0].fd = srtp->rtp_socket;
    pollfds[0].events = POLLIN;
    pollfds[0].revents = 0;

    pollfds[1].fd = srtp->rtcp_socket;
    pollfds[1].events = POLLIN;
    pollfds[1].revents = 0;


    while(1)
    {
        poll(pollfds,2,-1);

        if ( pollfds[0].revents & POLLIN )
        {
            int rx,wr;
            pollfds[0].revents = 0;

            rx = recv(pollfds[0].fd, rxbuf, 32768,0);

            if ( rx>12 && rxbuf[12] == 0x47 )
            {
                wr= write(srtp->fd,&rxbuf[12],rx-12);
                DEBUG(MSG_DATA,"RTP: rd %d  wr %d\n",rx,wr);
            }
        }

        if ( pollfds[1].revents & POLLIN )
        {
            int rx;
            pollfds[1].revents = 0;

            rx=recv(pollfds[1].fd, rxbuf, 32768,0);
            rtp_data(rxbuf,rx);
            DEBUG(MSG_DATA,"RTCP: rd %d\n",rx);
        }

    }
    return NULL;
}



t_satip_rtp*  satip_rtp_new(int fd)
{
    t_satip_rtp* srtp;
    int rtp_sock, rtcp_sock;
    int rtp_port, rtcp_port;
    struct timespec ts;
    int attempts=PORT_RANGE/2;


    clock_gettime(CLOCK_REALTIME,&ts);

    srandom(ts.tv_nsec);

    while ( --attempts > 0 )
    {
        struct sockaddr_in inaddr;

        rtp_port= PORT_BASE + ( random()% (PORT_RANGE-1) );
        rtcp_port = rtp_port+1;

        rtp_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
        rtcp_sock= socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);

        memset(&inaddr, 0, sizeof(inaddr));
        inaddr.sin_family = AF_INET;
        inaddr.sin_addr.s_addr = htonl(INADDR_ANY);
        inaddr.sin_port = htons(rtp_port);

        if (bind(rtp_sock, (struct sockaddr *) &inaddr, sizeof(inaddr)) < 0)
        {
            close(rtp_sock);
            close(rtcp_sock);
            continue;
        }

#if 0
        {
            struct ip_mreq group;
            group.imr_multiaddr.s_addr = inet_addr("224.16.16.1");
            group.imr_interface.s_addr = inet_addr("192.168.178.57");
            if (setsockopt(rtp_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                           (char *)&group, sizeof(group)) < 0)
            {
                close(rtp_sock);
                close(rtcp_sock);
                ERROR(MSG_NET,"error adding multicast group\n");
                exit(1);
            }
        }
#endif


        memset(&inaddr, 0, sizeof(inaddr));
        inaddr.sin_family = AF_INET;
        inaddr.sin_addr.s_addr = htonl(INADDR_ANY);
        inaddr.sin_port = htons(rtcp_port);

        if (bind(rtcp_sock, (struct sockaddr *) &inaddr, sizeof(inaddr)) < 0)
        {
            close(rtp_sock);
            close(rtcp_sock);
            continue;
        }

        INFO(MSG_NET,"rtp/rtcp port %d/%d\n",rtp_port,rtcp_port);
        break;
    }

    if (attempts <= 0)
        return NULL;

    srtp=(t_satip_rtp*)malloc(sizeof(t_satip_rtp));

    srtp->fd = fd;
    srtp->rtp_port    = rtp_port;
    srtp->rtp_socket  = rtp_sock;
    srtp->rtcp_port   = rtcp_port;
    srtp->rtcp_socket = rtcp_sock;

    pthread_create( &srtp->thread, NULL, rtp_receiver, srtp);

    return srtp;
}


int satip_rtp_port(t_satip_rtp* srtp)
{
    return srtp->rtp_port;
}