ref: d8a4fc5b2a332d0e03294c2ad170663df0482e07
dir: /src/opusrtp.c/
/* dump opus rtp packets into an ogg file
*
* compile with: gcc -g -Wall -o opusrtc opusrtp.c -lpcap -logg
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pcap.h>
#include <ogg/ogg.h>
/* state struct for passing around our handles */
typedef struct {
ogg_stream_state *stream;
FILE *out;
int seq;
} 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;
}
/* manufacture a generic OpusHead packet */
ogg_packet *op_opushead(void)
{
int size = 19;
unsigned char *data = malloc(size);
ogg_packet *op = malloc(sizeof(*op));
if (!data) {
fprintf(stderr, "Couldn't allocate data buffer.\n");
return NULL;
}
if (!op) {
fprintf(stderr, "Couldn't allocate Ogg packet.\n");
return NULL;
}
memcpy(data, "OpusHead", 8); /* identifier */
data[8] = 1; /* version */
data[9] = 2; /* channels */
le16(data+10, 0); /* pre-skip */
le32(data + 12, 48000); /* 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");
return NULL;
}
if (!op) {
fprintf(stderr, "Couldn't allocate Ogg packet.\n");
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(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 = 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);
}
}
/* helper, write out available ogg pages */
int ogg_write(state *params)
{
ogg_page page;
if (!params || !params->stream || !params->out) {
return -1;
}
while (ogg_stream_pageout(params->stream, &page)) {
fwrite(page.header, 1, page.header_len, params->out);
fwrite(page.body, 1, page.body_len, params->out);
}
return 0;
}
/* helper, flush remaining ogg data */
int ogg_flush(state *params)
{
ogg_page page;
if (!params || !params->stream || !params->out) {
return -1;
}
while (ogg_stream_flush(params->stream, &page)) {
fwrite(page.header, 1, page.header_len, params->out);
fwrite(page.body, 1, page.body_len, params->out);
}
return 0;
}
typedef struct {
unsigned char src[6], dst[6]; /* ethernet MACs */
int type;
} eth_header;
typedef struct {
int version;
int header_size;
unsigned char src[4], dst[4]; /* ipv4 addrs */
int protocol;
} ip_header;
typedef struct {
int src, dst; /* ports */
int size, checksum;
} udp_header;
typedef struct {
int version;
int type;
int pad, ext, cc, mark;
int seq, time;
int ssrc;
int header_size;
int payload_size;
} rtp_header;
/* pcap 'got_packet' callback */
void write_packet(u_char *args, const struct pcap_pkthdr *header,
const u_char *packet)
{
state *params = (state *)args;
eth_header eth;
ip_header ip;
udp_header udp;
rtp_header rtp;
fprintf(stderr, "Got %d byte packet (%d bytes captured)\n",
header->len, header->caplen);
/* eth header is always 14 bytes */
if (header->caplen < 14) {
fprintf(stderr, "Packet too short for eth\n");
return;
}
memcpy(eth.src, packet, 6);
memcpy(eth.dst, packet + 6, 6);
eth.type = packet[12] << 8 | packet[13];
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]);
/* ipv4 header */
if (header->caplen < 14 + 20) {
fprintf(stderr, "Packet too short for ipv4\n");
return;
}
ip.version = (packet[14+0] >> 4) & 0x0f;
ip.header_size = 4 * (packet[14+0] & 0x0f);
ip.protocol = packet[14 + 9];
memcpy(ip.src, packet + 14 + 12, 4);
memcpy(ip.dst, packet + 14 + 16, 4);
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 (header->caplen < 14 + ip.header_size) {
fprintf(stderr, "Packet too short for ipv4 with options\n");
return;
}
if (header->caplen < 14 + ip.header_size + 8) {
fprintf(stderr, "Packet too short for udp\n");
return;
}
udp.src = packet[14+ip.header_size] << 8 |
packet[14+ip.header_size + 1];
udp.dst = packet[14+ip.header_size + 2] << 8 |
packet[14+ip.header_size + 3];
udp.size = packet[14+ip.header_size + 4] << 8 |
packet[14+ip.header_size + 5];
udp.checksum = packet[14+ip.header_size + 6] << 8 |
packet[14+ip.header_size + 7];
fprintf(stderr, " udp %d bytes %d -> %d crc 0x%04x\n",
udp.size, udp.src, udp.dst, udp.checksum);
if (header->caplen < 14 + ip.header_size + 8 + 12) {
fprintf(stderr, "Packet too short for rtp\n");
return;
}
rtp.version = (packet[14+ip.header_size+8 + 0] >> 6) & 3;
rtp.pad = (packet[14+ip.header_size+8] >> 5) & 1;
rtp.ext = (packet[14+ip.header_size+8] >> 4) & 1;
rtp.cc = packet[14+ip.header_size+8] & 7;
rtp.header_size = 12 + 4 * rtp.cc;
rtp.payload_size = udp.size - 8 - rtp.header_size;
rtp.mark = (packet[14+ip.header_size+8 + 1] >> 7) & 1;
rtp.type = (packet[14+ip.header_size+8 + 1]) & 127;
rtp.seq = packet[14+ip.header_size+8 + 2] << 8 |
packet[14+ip.header_size+8 + 3];
rtp.time = packet[14+ip.header_size+8 + 4] << 24 |
packet[14+ip.header_size+8 + 5] << 16 |
packet[14+ip.header_size+8 + 6] << 8 |
packet[14+ip.header_size+8 + 7];
rtp.ssrc = packet[14+ip.header_size+8 + 8] << 24 |
packet[14+ip.header_size+8 + 9] << 16 |
packet[14+ip.header_size+8 + 10] << 8 |
packet[14+ip.header_size+8 + 11];
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 (header->caplen < 14 + ip.header_size + 8 + rtp.header_size) {
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;
if (rtp.type != 109) {
fprintf(stderr, "skipping non-opus packet\n");
return;
}
/* write the payload to our opus file */
int size = header->caplen - 14 - ip.header_size - 8 - rtp.header_size;
unsigned char *data = packet + 14+ip.header_size+8 + rtp.header_size;
ogg_packet *op = op_from_pkt(data, size);
op->granulepos = 960*rtp.seq;
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);
}
}
int main(int argc, char *argv[])
{
state *params;
pcap_t *pcap;
char *dev = "lo";
int port = 55555;
char errbuf[PCAP_ERRBUF_SIZE];
ogg_packet *op;
/* set up */
pcap = pcap_open_live(dev, 9600, 0, 1000, errbuf);
if (pcap == NULL) {
fprintf(stderr, "Couldn't open device %s: %s\n", dev, errbuf);
return(2);
}
params = malloc(sizeof(state));
if (!params) {
fprintf(stderr, "Couldn't allocate param struct.\n");
return -1;
}
params->stream = malloc(sizeof(ogg_stream_state));
if (!params->stream) {
fprintf(stderr, "Couldn't allocate stream struct.\n");
return -1;
}
if (ogg_stream_init(params->stream, rand()) < 0) {
fprintf(stderr, "Couldn't initialize Ogg stream state.\n");
return -1;
}
params->out = fopen("rtpdump.opus", "wb");
if (!params->out) {
fprintf(stderr, "Couldn't open output file.\n");
return -2;
}
params->seq = 0;
/* write stream headers */
op = op_opushead();
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 */
fprintf(stderr, "Capturing packets\n");
pcap_loop(pcap, 300, write_packet, (u_char *)params);
/* write outstanding data */
ogg_flush(params);
/* clean up */
fclose(params->out);
ogg_stream_destroy(params->stream);
free(params);
pcap_close(pcap);
return 0;
}