shithub: opus-tools

ref: 32d4b4758a14b15544ba1870aa251914b80774eb
dir: /src/opusrtp.c/

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/* Copyright 2012 Mozilla Foundation
   Copyright 2012 Xiph.Org Foundation
   Copyright 2012 Gregory Maxwell

   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.

   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 FOUNDATION 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.
 */

/* dump opus rtp packets into an ogg file
 *
 * compile with: cc -g -Wall -o opusrtc opusrtp.c -lpcap -logg
 *
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <getopt.h>

#ifndef _WIN32
# include <sys/types.h>
# include <sys/socket.h>
# include <netinet/in.h>
# include <arpa/inet.h>
# include <errno.h>

# if defined HAVE_MACH_ABSOLUTE_TIME
#  include <mach/mach_time.h>
# elif !(defined HAVE_CLOCK_GETTIME && defined CLOCK_REALTIME && \
         defined HAVE_NANOSLEEP)
#  include <sys/time.h>
# endif
#endif

#ifdef HAVE_PCAP
# include <pcap.h>
#endif
#include <opus.h>
#include <ogg/ogg.h>

#define SNIFF_DEVICE "lo0"
#define DYNAMIC_PAYLOAD_TYPE_MIN 96

/* state struct for passing around our handles */
typedef struct {
  ogg_stream_state *stream;
  FILE *out;
  int seq;
  ogg_int64_t granulepos;
  int linktype;
  int payload_type;
} state;

/* helper, write a little-endian 32 bit int to memory */
void le32(unsigned char *p, int v)
{
  p[0] = v & 0xff;
  p[1] = (v >> 8) & 0xff;
  p[2] = (v >> 16) & 0xff;
  p[3] = (v >> 24) & 0xff;
}

/* helper, write a little-endian 16 bit int to memory */
void le16(unsigned char *p, int v)
{
  p[0] = v & 0xff;
  p[1] = (v >> 8) & 0xff;
}

/* helper, write a big-endian 32 bit int to memory */
void be32(unsigned char *p, int v)
{
  p[0] = (v >> 24) & 0xff;
  p[1] = (v >> 16) & 0xff;
  p[2] = (v >> 8) & 0xff;
  p[3] = v & 0xff;
}

/* helper, write a big-endian 16 bit int to memory */
void be16(unsigned char *p, int v)
{
  p[0] = (v >> 8) & 0xff;
  p[1] = v & 0xff;
}

/* manufacture a generic OpusHead packet */
ogg_packet *op_opushead(int samplerate, int channels)
{
  int size = 19;
  unsigned char *data = malloc(size);
  ogg_packet *op = malloc(sizeof(*op));

  if (!data) {
    fprintf(stderr, "Couldn't allocate data buffer.\n");
    free(op);
    return NULL;
  }
  if (!op) {
    fprintf(stderr, "Couldn't allocate Ogg packet.\n");
    free(data);
    return NULL;
  }

  memcpy(data, "OpusHead", 8);  /* identifier */
  data[8] = 1;                  /* version */
  data[9] = channels;           /* channels */
  le16(data+10, 0);             /* pre-skip */
  le32(data + 12, samplerate);  /* original sample rate */
  le16(data + 16, 0);           /* gain */
  data[18] = 0;                 /* channel mapping family */

  op->packet = data;
  op->bytes = size;
  op->b_o_s = 1;
  op->e_o_s = 0;
  op->granulepos = 0;
  op->packetno = 0;

  return op;
}


/* manufacture a generic OpusTags packet */
ogg_packet *op_opustags(void)
{
  char *identifier = "OpusTags";
  char *vendor = "opus rtp packet dump";
  int size = strlen(identifier) + 4 + strlen(vendor) + 4;
  unsigned char *data = malloc(size);
  ogg_packet *op = malloc(sizeof(*op));

  if (!data) {
    fprintf(stderr, "Couldn't allocate data buffer.\n");
    free(op);
    return NULL;
  }
  if (!op) {
    fprintf(stderr, "Couldn't allocate Ogg packet.\n");
    free(data);
    return NULL;
  }

  memcpy(data, identifier, 8);
  le32(data + 8, strlen(vendor));
  memcpy(data + 12, vendor, strlen(vendor));
  le32(data + 12 + strlen(vendor), 0);

  op->packet = data;
  op->bytes = size;
  op->b_o_s = 0;
  op->e_o_s = 0;
  op->granulepos = 0;
  op->packetno = 1;

  return op;
}

ogg_packet *op_from_pkt(const unsigned char *pkt, int len)
{
  ogg_packet *op = malloc(sizeof(*op));
  if (!op) {
    fprintf(stderr, "Couldn't allocate Ogg packet.\n");
    return NULL;
  }

  op->packet = (unsigned char *)pkt;
  op->bytes = len;
  op->b_o_s = 0;
  op->e_o_s = 0;

  return op;
}

/* free a packet and its contents */
void op_free(ogg_packet *op)
{
  if (op) {
    if (op->packet) {
      free(op->packet);
    }
    free(op);
  }
}

/* check if an ogg page begins an opus stream */
int is_opus(ogg_page *og)
{
  ogg_stream_state os;
  ogg_packet op;

  ogg_stream_init(&os, ogg_page_serialno(og));
  ogg_stream_pagein(&os, og);
  if (ogg_stream_packetout(&os, &op) == 1) {
    if (op.bytes >= 19 && !memcmp(op.packet, "OpusHead", 8)) {
      ogg_stream_clear(&os);
      return 1;
    }
  }
  ogg_stream_clear(&os);
  return 0;
}

/* helper, write out available ogg pages */
int ogg_write(state *params)
{
  ogg_page page;
  size_t written;

  if (!params || !params->stream || !params->out) {
    return -1;
  }

  while (ogg_stream_pageout(params->stream, &page)) {
    written = fwrite(page.header, 1, page.header_len, params->out);
    if (written != (size_t)page.header_len) {
      fprintf(stderr, "Error writing Ogg page header\n");
      return -2;
    }
    written = fwrite(page.body, 1, page.body_len, params->out);
    if (written != (size_t)page.body_len) {
      fprintf(stderr, "Error writing Ogg page body\n");
      return -3;
    }
  }

  return 0;
}

/* helper, flush remaining ogg data */
int ogg_flush(state *params)
{
  ogg_page page;
  size_t written;

  if (!params || !params->stream || !params->out) {
    return -1;
  }

  while (ogg_stream_flush(params->stream, &page)) {
    written = fwrite(page.header, 1, page.header_len, params->out);
    if (written != (size_t)page.header_len) {
      fprintf(stderr, "Error writing Ogg page header\n");
      return -2;
    }
    written = fwrite(page.body, 1, page.body_len, params->out);
    if (written != (size_t)page.body_len) {
      fprintf(stderr, "Error writing Ogg page body\n");
      return -3;
    }
  }

  return 0;
}

#define ETH_HEADER_LEN 14
typedef struct {
  unsigned char src[6], dst[6]; /* ethernet MACs */
  int type;
} eth_header;

#define LOOP_HEADER_LEN 4
typedef struct {
  int family;
} loop_header;

#define IP_HEADER_MIN 20
typedef struct {
  int version;
  int header_size;
  unsigned char src[4], dst[4]; /* ipv4 addrs */
  int protocol;
} ip_header;

#define UDP_HEADER_LEN 8
typedef struct {
  int src, dst; /* ports */
  int size, checksum;
} udp_header;

#define RTP_HEADER_MIN 12
typedef struct {
  int version;
  int type;
  int pad, ext, cc, mark;
  int seq, time;
  int ssrc;
  int *csrc;
  int header_size;
  int payload_size;
} rtp_header;

/* helper, read a big-endian 16 bit int from memory */
static int rbe16(const unsigned char *p)
{
  int v = p[0] << 8 | p[1];
  return v;
}

/* helper, read a big-endian 32 bit int from memory */
static int rbe32(const unsigned char *p)
{
  int v = p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
  return v;
}

/* helper, read a native-endian 32 bit int from memory */
static int rne32(const unsigned char *p)
{
  /* On x86 we could just cast, but that might not meet
   * arm alignment requirements. */
  int d = 0;
  memcpy(&d, p, 4);
  return d;
}

int parse_eth_header(const unsigned char *packet, int size, eth_header *eth)
{
  if (!packet || !eth) {
    return -2;
  }
  if (size < ETH_HEADER_LEN) {
    fprintf(stderr, "Packet too short for eth\n");
    return -1;
  }
  memcpy(eth->src, packet + 0, 6);
  memcpy(eth->dst, packet + 6, 6);
  eth->type = rbe16(packet + 12);

  return 0;
}

/* used by the darwin loopback interface, at least */
int parse_loop_header(const unsigned char *packet, int size, loop_header *loop)
{
  if (!packet || !loop) {
    return -2;
  }
  if (size < LOOP_HEADER_LEN) {
    fprintf(stderr, "Packet too short for loopback\n");
    return -1;
  }
  /* protocol is in host byte order on osx. may be big endian on openbsd? */
  loop->family = rne32(packet);

  return 0;
}

int parse_ip_header(const unsigned char *packet, int size, ip_header *ip)
{
  if (!packet || !ip) {
    return -2;
  }
  if (size < IP_HEADER_MIN) {
    fprintf(stderr, "Packet too short for ip\n");
    return -1;
  }

  ip->version = (packet[0] >> 4) & 0x0f;
  if (ip->version != 4) {
    fprintf(stderr, "unhandled ip version %d\n", ip->version);
    return 1;
  }

  /* ipv4 header */
  ip->header_size = 4 * (packet[0] & 0x0f);
  ip->protocol = packet[9];
  memcpy(ip->src, packet + 12, 4);
  memcpy(ip->dst, packet + 16, 4);

  if (size < ip->header_size) {
    fprintf(stderr, "Packet too short for ipv4 with options\n");
    return -1;
  }

  return 0;
}

int parse_udp_header(const unsigned char *packet, int size, udp_header *udp)
{
  if (!packet || !udp) {
    return -2;
  }
  if (size < UDP_HEADER_LEN) {
    fprintf(stderr, "Packet too short for udp\n");
    return -1;
  }

  udp->src = rbe16(packet);
  udp->dst = rbe16(packet + 2);
  udp->size = rbe16(packet + 4);
  udp->checksum = rbe16(packet + 6);

  return 0;
}


int parse_rtp_header(const unsigned char *packet, int size, rtp_header *rtp)
{
  if (!packet || !rtp) {
    return -2;
  }
  if (size < RTP_HEADER_MIN) {
    fprintf(stderr, "Packet too short for rtp\n");
    return -1;
  }
  rtp->version = (packet[0] >> 6) & 3;
  rtp->pad = (packet[0] >> 5) & 1;
  rtp->ext = (packet[0] >> 4) & 1;
  rtp->cc = packet[0] & 7;
  rtp->header_size = 12 + 4 * rtp->cc;
  if (rtp->ext == 1) {
    uint16_t ext_length;
    rtp->header_size += 4;
    ext_length = rbe16(packet + rtp->header_size - 2);
    rtp->header_size += ext_length * 4;
  }
  rtp->payload_size = size - rtp->header_size;

  rtp->mark = (packet[1] >> 7) & 1;
  rtp->type = (packet[1]) & 127;
  rtp->seq  = rbe16(packet + 2);
  rtp->time = rbe32(packet + 4);
  rtp->ssrc = rbe32(packet + 8);
  rtp->csrc = NULL;
  if (size < rtp->header_size) {
    fprintf(stderr, "Packet too short for RTP header\n");
    return -1;
  }

  return 0;
}

int serialize_rtp_header(unsigned char *packet, int size, rtp_header *rtp)
{
  int i;

  if (!packet || !rtp) {
    return -2;
  }
  if (size < RTP_HEADER_MIN) {
    fprintf(stderr, "Packet buffer too short for RTP\n");
    return -1;
  }
  if (size < rtp->header_size) {
    fprintf(stderr, "Packet buffer too short for declared RTP header size\n");
    return -3;
  }
  packet[0] = ((rtp->version & 3) << 6) |
              ((rtp->pad & 1) << 5) |
              ((rtp->ext & 1) << 4) |
              ((rtp->cc & 7));
  packet[1] = ((rtp->mark & 1) << 7) |
              ((rtp->type & 127));
  be16(packet+2, rtp->seq);
  be32(packet+4, rtp->time);
  be32(packet+8, rtp->ssrc);
  if (rtp->cc && rtp->csrc) {
    for (i = 0; i < rtp->cc; i++) {
      be32(packet + 12 + i*4, rtp->csrc[i]);
    }
  }

  return 0;
}

int update_rtp_header(rtp_header *rtp)
{
  rtp->header_size = 12 + 4 * rtp->cc;
  return 0;
}

#ifndef _WIN32
/*
 * Wait for the next time slot, which begins delta nanoseconds after the
 * start of the previous time slot, or in the case of the first call at
 * the time of the call.  delta must be in the range 0..999999999.
 */
void wait_for_time_slot(int delta)
{
# if defined HAVE_MACH_ABSOLUTE_TIME
  /* Apple */
  static mach_timebase_info_data_t tbinfo;
  static uint64_t target;

  if (tbinfo.numer == 0) {
    mach_timebase_info(&tbinfo);
    target = mach_absolute_time();
  } else {
    target += tbinfo.numer == tbinfo.denom
      ? (uint64_t)delta : (uint64_t)delta * tbinfo.denom / tbinfo.numer;
    mach_wait_until(target);
  }
# elif defined HAVE_CLOCK_GETTIME && defined CLOCK_REALTIME && \
       defined HAVE_NANOSLEEP
  /* try to use POSIX monotonic clock */
  static int initialized = 0;
  static clockid_t clock_id;
  static struct timespec target;

  if (!initialized) {
#  if defined CLOCK_MONOTONIC && \
      defined _POSIX_MONOTONIC_CLOCK && _POSIX_MONOTONIC_CLOCK >= 0
    if (
#   if _POSIX_MONOTONIC_CLOCK == 0
        sysconf(_SC_MONOTONIC_CLOCK) > 0 &&
#   endif
        clock_gettime(CLOCK_MONOTONIC, &target) == 0) {
      clock_id = CLOCK_MONOTONIC;
      initialized = 1;
    } else
#  endif
    if (clock_gettime(CLOCK_REALTIME, &target) == 0) {
      clock_id = CLOCK_REALTIME;
      initialized = 1;
    }
  } else {
    target.tv_nsec += delta;
    if (target.tv_nsec >= 1000000000) {
      ++target.tv_sec;
      target.tv_nsec -= 1000000000;
    }
#  if defined HAVE_CLOCK_NANOSLEEP && \
      defined _POSIX_CLOCK_SELECTION && _POSIX_CLOCK_SELECTION > 0
    clock_nanosleep(clock_id, TIMER_ABSTIME, &target, NULL);
#  else
    {
      /* convert to relative time */
      struct timespec rel;
      if (clock_gettime(clock_id, &rel) == 0) {
        rel.tv_sec = target.tv_sec - rel.tv_sec;
        rel.tv_nsec = target.tv_nsec - rel.tv_nsec;
        if (rel.tv_nsec < 0) {
          rel.tv_nsec += 1000000000;
          --rel.tv_sec;
        }
        if (rel.tv_sec >= 0 && (rel.tv_sec > 0 || rel.tv_nsec > 0)) {
          nanosleep(&rel, NULL);
        }
      }
    }
#  endif
  }
# else
  /* fall back to the old non-monotonic gettimeofday() */
  static int initialized = 0;
  static struct timeval target;
  struct timeval now;
  int nap;

  if (!initialized) {
    gettimeofday(&target, NULL);
    initialized = 1;
  } else {
    delta /= 1000;
    target.tv_usec += delta;
    if (target.tv_usec >= 1000000) {
      ++target.tv_sec;
      target.tv_usec -= 1000000;
    }

    gettimeofday(&now, NULL);
    nap = target.tv_usec - now.tv_usec;
    if (now.tv_sec != target.tv_sec) {
      if (now.tv_sec > target.tv_sec) nap = 0;
      else if (target.tv_sec - now.tv_sec == 1) nap += 1000000;
      else nap = 1000000;
    }
    if (nap > delta) nap = delta;
    if (nap > 0) {
#  if defined HAVE_USLEEP
      usleep(nap);
#  else
      struct timeval timeout;
      timeout.tv_sec = 0;
      timeout.tv_usec = nap;
      select(0, NULL, NULL, NULL, &timeout);
#  endif
    }
  }
# endif
}

int send_rtp_packet(int fd, struct sockaddr *sin,
    rtp_header *rtp, const unsigned char *opus)
{
  unsigned char *packet;
  int ret;

  update_rtp_header(rtp);
  packet = malloc(rtp->header_size + rtp->payload_size);
  if (!packet) {
    fprintf(stderr, "Couldn't allocate packet buffer\n");
    return -1;
  }
  serialize_rtp_header(packet, rtp->header_size, rtp);
  memcpy(packet + rtp->header_size, opus, rtp->payload_size);
  ret = sendto(fd, packet, rtp->header_size + rtp->payload_size, 0,
      sin, sizeof(*sin));
  if (ret < 0) {
    fprintf(stderr, "error sending: %s\n", strerror(errno));
  }
  free(packet);

  return ret;
}

int rtp_send_file(const char *filename, const char *dest, int port,
        int payload_type)
{
  rtp_header rtp;
  int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  struct sockaddr_in sin;
  int optval = 0;
  int ret;
  FILE *in;
  ogg_sync_state oy;
  ogg_stream_state os;
  ogg_page og;
  ogg_packet op;
  int headers = 0;
  char *in_data;
  const long in_size = 8192;
  size_t in_read;

  if (fd < 0) {
    fprintf(stderr, "Couldn't create socket\n");
    return fd;
  }
  sin.sin_family = AF_INET;
  sin.sin_port = htons(port);
  if ((sin.sin_addr.s_addr = inet_addr(dest)) == INADDR_NONE) {
    fprintf(stderr, "Invalid address %s\n", dest);
    return -1;
  }

  ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(int));
  if (ret < 0) {
    fprintf(stderr, "Couldn't set socket options\n");
    return ret;
  }

  rtp.version = 2;
  rtp.type = payload_type;
  rtp.pad = 0;
  rtp.ext = 0;
  rtp.cc = 0;
  rtp.mark = 0;
  rtp.seq = rand();
  rtp.time = rand();
  rtp.ssrc = rand();
  rtp.csrc = NULL;
  rtp.header_size = 0;
  rtp.payload_size = 0;

  fprintf(stderr, "Sending %s...\n", filename);
  in = fopen(filename, "rb");

  if (!in) {
    fprintf(stderr, "Couldn't open input file '%s'\n", filename);
    return -1;
  }
  ret = ogg_sync_init(&oy);
  if (ret < 0) {
    fprintf(stderr, "Couldn't initialize Ogg sync state\n");
    fclose(in);
    return ret;
  }
  while (!feof(in)) {
    in_data = ogg_sync_buffer(&oy, in_size);
    if (!in_data) {
      fprintf(stderr, "ogg_sync_buffer failed\n");
      fclose(in);
      return -1;
    }
    in_read = fread(in_data, 1, in_size, in);
    ret = ogg_sync_wrote(&oy, in_read);
    if (ret < 0) {
      fprintf(stderr, "ogg_sync_wrote failed\n");
      fclose(in);
      return ret;
    }
    while (ogg_sync_pageout(&oy, &og) == 1) {
      if (headers == 0) {
        if (is_opus(&og)) {
          /* this is the start of an Opus stream */
          ret = ogg_stream_init(&os, ogg_page_serialno(&og));
          if (ret < 0) {
            fprintf(stderr, "ogg_stream_init failed\n");
            fclose(in);
            return ret;
          }
          headers++;
        } else if (!ogg_page_bos(&og)) {
          /* We're past the header and haven't found an Opus stream.
           * Time to give up. */
          fclose(in);
          return 1;
        } else {
          /* try again */
          continue;
        }
      }
      /* submit the page for packetization */
      ret = ogg_stream_pagein(&os, &og);
      if (ret < 0) {
        fprintf(stderr, "ogg_stream_pagein failed\n");
        fclose(in);
        return ret;
      }
      /* read and process available packets */
      while (ogg_stream_packetout(&os,&op) == 1) {
        int samples;
        /* skip header packets */
        if (headers == 1 && op.bytes >= 19 && !memcmp(op.packet, "OpusHead", 8)) {
          headers++;
          continue;
        }
        if (headers == 2 && op.bytes >= 16 && !memcmp(op.packet, "OpusTags", 8)) {
          headers++;
          continue;
        }
        /* get packet duration */
        samples = opus_packet_get_nb_samples(op.packet, op.bytes, 48000);
        if (samples <= 0) {
          fprintf(stderr, "skipping invalid packet\n");
          continue;
        }
        /* update the rtp header and send */
        rtp.seq++;
        rtp.time += samples;
        rtp.payload_size = op.bytes;
        fprintf(stderr, "rtp %d %d %d %3d ms %5d bytes\n",
            rtp.type, rtp.seq, rtp.time, samples/48, rtp.payload_size);
        send_rtp_packet(fd, (struct sockaddr *)&sin, &rtp, op.packet);
        /* convert number of 48 kHz samples to nanoseconds without overflow */
        wait_for_time_slot(samples*62500/3);
      }
    }
  }

  if (headers > 0)
    ogg_stream_clear(&os);
  ogg_sync_clear(&oy);
  fclose(in);
  return 0;
}
#else /* _WIN32 */
int rtp_send_file(const char *filename, const char *dest, int port,
        int payload_type)
{
  fprintf(stderr, "Cannot send '%s to %s:%d'. Socket support not available.\n",
          filename, dest, port);
  (void)payload_type;
  return -2;
}
#endif


#ifdef HAVE_PCAP
/* pcap 'got_packet' callback */
void write_packet(u_char *args, const struct pcap_pkthdr *header,
                  const u_char *data)
{
  state *params = (state *)(void *)args;
  const unsigned char *packet;
  int size;
  eth_header eth;
  loop_header loop;
  ip_header ip;
  udp_header udp;
  rtp_header rtp;
  ogg_packet *op;
  int samples;

  fprintf(stderr, "Got %d byte packet (%d bytes captured)\n",
          header->len, header->caplen);
  packet = data;
  size = header->caplen;

  /* parse the link-layer header */
  switch (params->linktype) {
    case DLT_EN10MB:
      if (parse_eth_header(packet, size, &eth)) {
        fprintf(stderr, "error parsing eth header\n");
        return;
      }
      fprintf(stderr, "  eth 0x%04x", eth.type);
      fprintf(stderr, " %02x:%02x:%02x:%02x:%02x:%02x ->",
              eth.src[0], eth.src[1], eth.src[2],
              eth.src[3], eth.src[4], eth.src[5]);
      fprintf(stderr, " %02x:%02x:%02x:%02x:%02x:%02x\n",
              eth.dst[0], eth.dst[1], eth.dst[2],
              eth.dst[3], eth.dst[4], eth.dst[5]);
      if (eth.type != 0x0800) {
        fprintf(stderr, "skipping packet: no IPv4\n");
        return;
      }
      packet += ETH_HEADER_LEN;
      size -= ETH_HEADER_LEN;
      break;
    case DLT_NULL:
      if (parse_loop_header(packet, size, &loop)) {
        fprintf(stderr, "error parsing loopback header\n");
        return;
      }
      fprintf(stderr, " loopback family %d\n", loop.family);
      if (loop.family != PF_INET) {
        fprintf(stderr, "skipping packet: not IP\n");
        return;
      }
      packet += LOOP_HEADER_LEN;
      size -= LOOP_HEADER_LEN;
      break;
    default:
      fprintf(stderr, "skipping packet: unrecognized linktype %d\n",
          params->linktype);
      return;
  }

  if (parse_ip_header(packet, size, &ip)) {
    fprintf(stderr, "error parsing ip header\n");
    return;
  }
  fprintf(stderr, " ipv%d protocol %d", ip.version, ip.protocol);
  fprintf(stderr, " %d.%d.%d.%d ->",
          ip.src[0], ip.src[1], ip.src[2], ip.src[3]);
  fprintf(stderr, " %d.%d.%d.%d",
          ip.dst[0], ip.dst[1], ip.dst[2], ip.dst[3]);
  fprintf(stderr, " header %d bytes\n", ip.header_size);
  if (ip.protocol != 17) {
    fprintf(stderr, "skipping packet: not UDP\n");
    return;
  }
  packet += ip.header_size;
  size -= ip.header_size;

  if (parse_udp_header(packet, size, &udp)) {
    fprintf(stderr, "error parsing udp header\n");
    return;
  }
  fprintf(stderr, "  udp %d bytes %d -> %d crc 0x%04x\n",
          udp.size, udp.src, udp.dst, udp.checksum);
  packet += UDP_HEADER_LEN;
  size -= UDP_HEADER_LEN;

  if (parse_rtp_header(packet, size, &rtp)) {
    fprintf(stderr, "error parsing rtp header\n");
    return;
  }
  fprintf(stderr, "  rtp 0x%08x %d %d %d",
          rtp.ssrc, rtp.type, rtp.seq, rtp.time);
  fprintf(stderr, "  v%d %s%s%s CC %d", rtp.version,
          rtp.pad ? "P":".", rtp.ext ? "X":".",
          rtp.mark ? "M":".", rtp.cc);
  fprintf(stderr, " %5d bytes\n", rtp.payload_size);

  if (!params->out) {
    return;
  }

  packet += rtp.header_size;
  size -= rtp.header_size;

  if (size < 0) {
    fprintf(stderr, "skipping short packet\n");
    return;
  }

  if (rtp.seq < params->seq) {
    fprintf(stderr, "skipping out-of-sequence packet\n");
    return;
  }
  params->seq = rtp.seq;

  /* look for first plausible payload_type if no payload type specified */
  if (params->payload_type < 0 && rtp.type >= DYNAMIC_PAYLOAD_TYPE_MIN) {
    const unsigned char *frames[48];
    opus_int16 fsizes[48];
    if (opus_packet_parse(packet, size, NULL, frames, fsizes, NULL) > 0) {
      /* this could be a valid Opus packet */
      fprintf(stderr, "recording stream with payload type %d\n", rtp.type);
      params->payload_type = rtp.type;
    }
  }

  if (rtp.type != params->payload_type) {
    fprintf(stderr, "skipping packet with payload type %d\n", rtp.type);
    return;
  }

  /* write the payload to our opus file */
  op = op_from_pkt(packet, size);
  op->packetno = rtp.seq;
  samples = opus_packet_get_nb_samples(packet, size, 48000);
  if (samples > 0) params->granulepos += samples;
  op->granulepos = params->granulepos;
  ogg_stream_packetin(params->stream, op);
  free(op);
  ogg_write(params);

  if (size < rtp.payload_size) {
    fprintf(stderr, "!! truncated %d uncaptured bytes\n",
            rtp.payload_size - size);
  } else if (samples <= 0) {
    fprintf(stderr, "!! invalid opus packet\n");
  }
}

/* use libpcap to capture packets and write them to a file */
int sniff(const char *input_file, const char *output_file, int payload_type,
        int samplerate, int channels)
{
  state *params;
  pcap_t *pcap;
  char errbuf[PCAP_ERRBUF_SIZE];
  ogg_packet *op;

  /* set up */
  if (input_file) {
    pcap = pcap_open_offline(input_file, errbuf);
    if (pcap == NULL) {
      fprintf(stderr,"Cannot open pcap file: %s\n%s\n", input_file, errbuf);
      return 1;
    }
  } else {
    pcap = pcap_open_live(SNIFF_DEVICE, 9600, 0, 1000, errbuf);
    if (pcap == NULL) {
      fprintf(stderr, "Cannot open device %s\n%s\n", SNIFF_DEVICE, errbuf);
      return 1;
    }
  }

  params = malloc(sizeof(state));
  if (!params) {
    fprintf(stderr, "Couldn't allocate param struct.\n");
    pcap_close(pcap);
    return 1;
  }
  params->linktype = pcap_datalink(pcap);
  params->stream = malloc(sizeof(ogg_stream_state));
  if (!params->stream) {
    fprintf(stderr, "Couldn't allocate stream struct.\n");
    free(params);
    pcap_close(pcap);
    return 1;
  }
  if (ogg_stream_init(params->stream, rand()) < 0) {
    fprintf(stderr, "Couldn't initialize Ogg stream state.\n");
    free(params->stream);
    free(params);
    pcap_close(pcap);
    return 1;
  }
  params->out = NULL;
  params->seq = 0;
  params->granulepos = 0;
  params->payload_type = payload_type;

  if (output_file) {
    if (strcmp(output_file, "-") == 0) {
      params->out = stdout;
    } else {
      params->out = fopen(output_file, "wb");
    }
    if (!params->out) {
      fprintf(stderr, "Couldn't open output file.\n");
      free(params->stream);
      free(params);
      pcap_close(pcap);
      return 1;
    }
    /* write stream headers */
    op = op_opushead(samplerate, channels);
    ogg_stream_packetin(params->stream, op);
    op_free(op);
    op = op_opustags();
    ogg_stream_packetin(params->stream, op);
    op_free(op);
    ogg_flush(params);
  }

  /* start capture loop */
  /* if reading from an input file, continue until EOF */
  fprintf(stderr, "Capturing packets\n");
  pcap_loop(pcap, input_file ? 0 : 300, write_packet, (u_char *)params);

  /* write outstanding data */
  if (params->out) {
    ogg_flush(params);
    if (params->out == stdout) {
      fflush(stdout);
    } else {
      fclose(params->out);
    }
    params->out = NULL;
  }

  /* clean up */
  ogg_stream_destroy(params->stream);
  free(params);
  pcap_close(pcap);
  return 0;
}
#endif /* HAVE_PCAP */

void opustools_version(void)
{
  printf("opusrtp %s %s\n", PACKAGE_NAME, PACKAGE_VERSION);
  printf("Copyright (C) 2012-2018 Xiph.Org Foundation\n");
}

void usage(char *exe)
{
  printf("Usage: %s [--extract file.pcap] [--sniff] <file.opus> [<file2.opus>]\n", exe);
  printf("\n");
  printf("Sends and receives Opus audio RTP streams.\n");
  printf("\nGeneral Options:\n");
  printf(" -h, --help             Show this help\n");
  printf(" -V, --version          Show version information\n");
  printf(" -q, --quiet            Suppress status output\n");
  printf(" -d, --destination addr Set destination IP address (default 127.0.0.1)\n");
  printf(" -p, --port n           Set destination port (default 1234)\n");
  printf(" -o, --output out.opus  Write Ogg Opus output file\n");
  printf(" -r, --rate n           Set output file sample rate (default 48000)\n");
  printf(" -c, --channels n       Set output file channel count (default 2)\n");
  printf(" -t, --type n           Set RTP payload type (default 120)\n");
  printf(" --sniff                Sniff loopback interface for Opus RTP streams\n");
  printf(" -e, --extract in.pcap  Extract from input pcap file\n");
  printf("\n");
  printf("By default, the given file(s) will be sent over RTP.\n");
}

int main(int argc, char *argv[])
{
  int option, i;
  const char *dest = "127.0.0.1";
  const char *input_pcap = NULL;
  const char *output_file = NULL;
  int pcap_mode = 0;
  int port = 1234;
  int payload_type = -1;
  int samplerate = 48000;
  int channels = 2;
  struct option long_options[] = {
    {"help", no_argument, NULL, 'h'},
    {"version", no_argument, NULL, 'V'},
    {"quiet", no_argument, NULL, 'q'},
    {"output", required_argument, NULL, 'o'},
    {"destination", required_argument, NULL, 'd'},
    {"port", required_argument, NULL, 'p'},
    {"rate", required_argument, NULL, 'r'},
    {"channels", required_argument, NULL, 'c'},
    {"type", required_argument, NULL, 't'},
    {"sniff", no_argument, NULL, 0},
    {"extract", required_argument, NULL, 'e'},
    {0, 0, 0, 0}
  };

  /* process command line arguments */
  while ((option = getopt_long(argc, argv, "hVqo:d:p:r:c:t:e:",
            long_options, &i)) != -1) {
    switch (option) {
      case 0:
        if (!strcmp(long_options[i].name, "sniff")) {
          pcap_mode = 1;
        } else {
          fprintf(stderr, "Unknown option - try %s --help.\n", argv[0]);
          return -1;
        }
        break;
      case 'V':
        opustools_version();
        return 0;
      case 'q':
        break;
      case 'o':
        if (optarg)
            output_file = optarg;
        break;
      case 'd':
        if (optarg)
            dest = optarg;
        break;
      case 'e':
        if (optarg) {
            input_pcap = optarg;
            pcap_mode = 1;
        }
        break;
      case 'p':
        if (optarg)
            port = atoi(optarg);
        break;
      case 'r':
        if (optarg)
            samplerate = atoi(optarg);
        break;
      case 'c':
        if (optarg)
            channels = atoi(optarg);
        break;
      case 't':
        if (optarg)
            payload_type = atoi(optarg);
        break;
      case 'h':
        usage(argv[0]);
        return 0;
      case '?':
      default:
        usage(argv[0]);
        return 1;
    }
  }

  if (optind < argc) {
    /* files to transmit were specified */
    if (pcap_mode) {
      fprintf(stderr, "Ogg Opus input files cannot be used with %s.\n",
        input_pcap ? "--extract" : "--sniff");
      return 1;
    }
    if (payload_type < 0) payload_type = 120;
    for (i = optind; i < argc; i++) {
      rtp_send_file(argv[i], dest, port, payload_type);
    }
    return 0;
  }

  if (pcap_mode) {
#ifdef HAVE_PCAP
    return sniff(input_pcap, output_file, payload_type, samplerate, channels);
#else
    (void)input_pcap;
    (void)output_file;
    (void)samplerate;
    (void)channels;
    fprintf(stderr, "Sorry, pcap support is disabled.\n");
    return 1;
#endif
  }

  usage(argv[0]);
  return 1;
}