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Message #01958
[Question #269935]: IP/UDP/RTP header compression issue
New question #269935 on rohc:
https://answers.launchpad.net/rohc/+question/269935
Hi,
I am trying to compress IP/UDP/RTP packet .But i am only getting 2 bytes of header compression out of 40 bytes. The following is my program.Please check it and suggest me where i am going wrong.
I am using O RTP library for rtp packet generation .
#include "rohc_rtp.h"
int runcond=1;
void stophandler(int signum)
{
runcond=0;
}
static int gen_random_num(const struct rohc_comp *const comp,void *const user_context)
{
return rand();
}
static bool rtp_detect(const unsigned char *const ip,
const unsigned char *const udp,
const unsigned char *const payload,
const unsigned int payload_size,
void *const rtp_private)
{
uint16_t udp_dport;
bool is_rtp;
/* check UDP destination port */
memcpy(&udp_dport, udp + 2, sizeof(uint16_t));
if(ntohs(udp_dport) == 10042)
{
/* we think that the UDP packet is a RTP packet */
fprintf(stderr, "RTP packet detected (expected UDP port)\n");
is_rtp = true;
}
else
{
/* we think that the UDP packet is not a RTP packet */
fprintf(stderr, "RTP packet not detected (wrong UDP port)\n");
is_rtp = false;
}
return is_rtp;
}
static void print_rohc_traces(void *const priv_ctxt,
const rohc_trace_level_t level,
const rohc_trace_entity_t entity,
const int profile,
const char *const format,
...)
{
va_list args;
va_start(args, format);
vfprintf(stdout, format, args);
va_end(args);
}
int main()
{
char buffer[160]="",data[256]="";
int i;
FILE *infile;
char *ssrc;
uint32_t user_ts=0;
int clockslide=0;
int jitter=0;
mblk_t *m=NULL;
uint8_t rtp_buffer[BUFFER_SIZE]="";
struct rohc_buf rtp_r_packet = rohc_buf_init_empty(rtp_buffer, BUFFER_SIZE);
uint8_t rohc_buffer[BUFFER_SIZE]="";
struct rohc_buf rohc_packet = rohc_buf_init_empty(rohc_buffer, BUFFER_SIZE);
struct rohc_comp *compressor=NULL;
unsigned int *rtpheader = (unsigned int*)data;
RtpSession *rtp_session=NULL;
rohc_status_t rohc_status;
rtp_header_t *rtp_h;
printf("Testing RTP header compression\n");
/*create ROHC compressor */
compressor = rohc_comp_new2(ROHC_SMALL_CID, ROHC_SMALL_CID_MAX,gen_random_num, NULL);
if(compressor == NULL)
{
printf("Failed create the ROHC compressor\n");
return 1;
}
if(!rohc_comp_set_traces_cb2(compressor, print_rohc_traces, NULL))
{
printf("failed to set the callback for traces on compressor\n");
return 1;
}
/* Compressor profile creation */
if(!rohc_comp_enable_profile(compressor, ROHC_PROFILE_RTP))
{
printf("failed to enable the RTP profile\n");
/* cleanup compressor, then leave with an error code */
rohc_comp_free(compressor);
return 1;
}
/*Prepare Fake RTP packet */
/* Create the actual packet that we will be sending */
ortp_init();
ortp_scheduler_init();
rtp_session=rtp_session_new(RTP_SESSION_SENDONLY);
rtp_session_set_scheduling_mode(rtp_session,1);
rtp_session_set_blocking_mode(rtp_session,1);
rtp_session_set_remote_addr(rtp_session,"192.168.1.36",5087);
rtp_session_set_payload_type(rtp_session,0);
ssrc=getenv("SSRC");
if (ssrc!=NULL) {
printf("using SSRC=%i.\n",atoi(ssrc));
rtp_session_set_ssrc(rtp_session,atoi(ssrc));
}
infile=fopen("/home/vravi/lat-tests/prepaid-press1-listen-lastcall.wav","r");
if (infile==NULL) {
perror("Cannot open file");
return -1;
}
signal(SIGINT,stophandler);
printf("Reading DATA FROM FILE AND CREATING RTP STREAM\n");
while( ((i=fread(buffer,1,160,infile))>0) && (runcond) )
{
rohc_buf_reset(&rtp_r_packet);
rohc_buf_reset(&rohc_packet);
m = rtp_session_create_packet_with_data(rtp_session,(char*)buffer,i,NULL);
((rtp_header_t*) m->b_rptr)->seq_number = 156;
((rtp_header_t*) m->b_rptr)->timestamp = time(0);
printf("SIZE OF ACTUAL RTP : < %d > , RTP HEADER LENGTH : < %d > , RTP PAYLOAD LENGTH : < %d > \n", msgdsize(m),rtpheader_size(m),rtppayload_size(m));
rtp_r_packet.len = 5 * 4 + 8 + 12 + rtppayload_size(m);
// rtp_r_packet.len = 5 * 4 + 8 + 12 ;
/* IPv4 header */
rohc_buf_byte_at(rtp_r_packet, 0) = 4 << 4; /* IP version 4 */
rohc_buf_byte_at(rtp_r_packet, 0) |= 5; /* IHL: minimal IPv4 header length (in 32-bit words) */
rohc_buf_byte_at(rtp_r_packet, 1) = 0; /* TOS */
rohc_buf_byte_at(rtp_r_packet, 2) = (rtp_r_packet.len >> 8) & 0xff; /* Total Length */
rohc_buf_byte_at(rtp_r_packet, 3) = rtp_r_packet.len & 0xff;
rohc_buf_byte_at(rtp_r_packet, 4) = 0; /* IP-ID */
rohc_buf_byte_at(rtp_r_packet, 5) = 0;
rohc_buf_byte_at(rtp_r_packet, 6) = 0; /* Fragment Offset and IP flags */
rohc_buf_byte_at(rtp_r_packet, 7) = 0;
rohc_buf_byte_at(rtp_r_packet, 8) = 1; /* TTL */
rohc_buf_byte_at(rtp_r_packet, 9) = 17; /* Protocol: UDP */
rohc_buf_byte_at(rtp_r_packet, 10) = 0xa9; /* fake Checksum */
rohc_buf_byte_at(rtp_r_packet, 11) = 0xa0;
rohc_buf_byte_at(rtp_r_packet, 12) = 0x01; /* Source address */
rohc_buf_byte_at(rtp_r_packet, 13) = 0x02;
rohc_buf_byte_at(rtp_r_packet, 14) = 0x03;
rohc_buf_byte_at(rtp_r_packet, 15) = 0x04;
rohc_buf_byte_at(rtp_r_packet, 16) = 0x05; /* Destination address */
rohc_buf_byte_at(rtp_r_packet, 17) = 0x06;
rohc_buf_byte_at(rtp_r_packet, 18) = 0x07;
rohc_buf_byte_at(rtp_r_packet, 19) = 0x08;
/* UDP header */
rohc_buf_byte_at(rtp_r_packet, 20) = 0x42; /* source port */
rohc_buf_byte_at(rtp_r_packet, 21) = 0x42;
rohc_buf_byte_at(rtp_r_packet, 22) = 0x27; /* destination port = 10042 */
rohc_buf_byte_at(rtp_r_packet, 23) = 0x3a;
rohc_buf_byte_at(rtp_r_packet, 24) = 0x00; /* UDP length */
//rohc_buf_byte_at(rtp_r_packet, 25) = 8 + 12;
rohc_buf_byte_at(rtp_r_packet, 25) = 8 + 12 + rtppayload_size(m);
rohc_buf_byte_at(rtp_r_packet, 26) = 0x00; /* UDP checksum = 0 */
rohc_buf_byte_at(rtp_r_packet, 27) = 0x00;
/* RTP header */
// rohc_buf_append(&rtp_r_packet, (uint8_t *)m->b_rptr , rtpheader_size(m));
// rohc_buf_append(&rtp_r_packet, (uint8_t *)m->b_cont->b_rptr , rtppayload_size(m));
memcpy(rohc_buf_data_at(rtp_r_packet, 28), (uint8_t *)m->b_rptr,rtpheader_size(m));
/* copy the payload just after the IP/UDP/RTP headers */
memcpy(rohc_buf_data_at(rtp_r_packet, 40), (uint8_t *)m->b_cont->b_rptr,rtppayload_size(m));
printf(" RTP detection Check uncompress \n");
if(!rohc_comp_set_rtp_detection_cb(compressor, rtp_detect, NULL))
{
printf("failed to set RTP detection callback\n");
return 1;
}
printf("IP/UDP/RTP PACKET SIZE BEFORE COMPRESSION : HEADER : < %d > , PAYLOAD : < %d > , TOTAL PACKET SIZE : < %d >\n" ,28 + rtpheader_size(m),rtppayload_size(m),28 + rtpheader_size(m) + rtppayload_size(m));
/*compress the packet */
rohc_status = rohc_compress4(compressor,rtp_r_packet, &rohc_packet);
if(rohc_status != ROHC_STATUS_OK)
{
printf("compression of fake RTP packet failed: %s (%d)\n",rohc_strerror(rohc_status), rohc_status);
rohc_comp_free(compressor);
fclose(infile);
rtp_session_destroy(rtp_session);
ortp_exit();
return 1;
}
/*Print the size of compressed one */
memset(buffer,0,sizeof(buffer));
}
fclose(infile);
rtp_session_destroy(rtp_session);
ortp_exit();
// ortp_global_stats_display();
/* Free compressor */
if(compressor){
rohc_comp_free(compressor);
}
return 0;
}
Regards,
V Ravi Kumar
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