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[Wei Wang <question229419@xxxxxxxxxxxxxxxxxxxxx>]

Question #229419 on rohc changed:
https://answers.launchpad.net/rohc/+question/229419

    Status: Answered => Open

Wei Wang is still having a problem:
Hi Friedrich,

I just copy/paste the main function of the simple_rohc_program.c file
here since there is no way to upload it.

~~~~~~~~~~~~~~~~~~~
int main(int argc, char **argv)
{
	struct rohc_comp *compressor;           /* the ROHC compressor */
    struct rohc_decomp *decompressor;
	unsigned char ip_packet[BUFFER_SIZE];   /* the buffer that will contain
	                                           the IPv4 packet to compress */
	unsigned int ip_packet_len;             /* the length (in bytes) of the
	                                           IPv4 packet */
	unsigned char rohc_packet[BUFFER_SIZE]; /* the buffer that will contain
	                                           the resulting ROHC packet */
	int rohc_packet_len;                    /* the length (in bytes) of the
	                                           resulting ROHC packet */
	unsigned int seed;
	unsigned int i;

    unsigned char udp_packet[BUFFER_SIZE];
    unsigned int udp_packet_len;
    unsigned char rtp_header[BUFFER_SIZE];
    unsigned char decomp_packet[BUFFER_SIZE];

	/* initialize the random generator */
	seed = time(NULL);
	srand(seed);

	/* Create a ROHC compressor with small CIDs, no jamming and no adaptation
	 * to encapsulation frames.
	 *
	 * See http://rohc-lib.org/doc/latest/group__rohc__comp.html#ga721fd34fc0cd9e1d789b693eb6bb6485
	 * for details about rohc_alloc_compressor in the API documentation.
	 */
	printf("\ncreate the ROHC compressor\n");
	compressor = rohc_alloc_compressor(ROHC_SMALL_CID_MAX, 0, 0, 0);
	if(compressor == NULL)
	{
		fprintf(stderr, "failed create the ROHC compressor\n");
		goto error;
	}
    decompressor = rohc_alloc_decompressor(compressor);

	/* set the callback for random numbers */
	if(!rohc_comp_set_random_cb(compressor, gen_random_num, NULL))
	{
		fprintf(stderr, "failed to set the callback for random numbers\n");
		goto release_compressor;
	}

	/* Enable the compression profiles you need (comment or uncomment some lines).
	 *
	 * See http://rohc-lib.org/doc/latest/group__rohc__comp.html#ga1a444eb91681521f726712a60a4df867
	 * for details about rohc_activate_profile in the API documentation.
	 */
	printf("\nenable several ROHC compression profiles\n");
	rohc_activate_profile(compressor, ROHC_PROFILE_UNCOMPRESSED);
	rohc_activate_profile(compressor, ROHC_PROFILE_UDP);
	rohc_activate_profile(compressor, ROHC_PROFILE_IP);
	//rohc_activate_profile(compressor, ROHC_PROFILE_UDPLITE);
	rohc_activate_profile(compressor, ROHC_PROFILE_RTP);
	//rohc_activate_profile(comp, ROHC_PROFILE_ESP);


	/* create a fake IP packet for the purpose of this simple program */
	printf("\nbuild a fake IP packet\n");
	ip_packet[0] = 4 << 4; /* IP version 4 */
	ip_packet[0] |= 5; /* IHL: minimal IPv4 header length (in 32-bit words) */
	ip_packet[1] = 0; /* TOS */
	ip_packet_len = 56; //5 * 4 + strlen(FAKE_PAYLOAD);
	ip_packet[2] = (htons(ip_packet_len) >> 8) & 0xff; /* Total Length */
	ip_packet[3] = htons(ip_packet_len) & 0xff;
	//ip_packet[2] = (ip_packet_len >> 8) & 0xff; /* Total Length */
	//ip_packet[3] = ip_packet_len & 0xff;
	ip_packet[4] = 0; /* IP-ID */
	ip_packet[5] = 0;
	ip_packet[6] = 0; /* Fragment Offset and IP flags */
	ip_packet[7] = 0;
	ip_packet[8] = 1; /* TTL */
	ip_packet[9] = 17; /* Protocol: unassigned number */
	ip_packet[10] = 0xbe; /* fake Checksum */
	ip_packet[11] = 0xef;
	ip_packet[12] = 0x01; /* Source address */
	ip_packet[13] = 0x02;
	ip_packet[14] = 0x03;
	ip_packet[15] = 0x04;
	ip_packet[16] = 0x05; /* Destination address */
	ip_packet[17] = 0x06;
	ip_packet[18] = 0x07;
	ip_packet[19] = 0x08;

    /* fake UDP headers, 8 bytes */
	udp_packet[0] = 0x01; /* Source address */
	udp_packet[1] = 0x02;
	udp_packet[2] = 0x05; /* Destination address */
	udp_packet[3] = 0x06;
    udp_packet_len = 8;
	udp_packet[4] = (udp_packet_len >> 8) & 0xff; /* Total Length */
	udp_packet[5] = udp_packet_len & 0xff;
	udp_packet[6] = 0xbe; /* fake Checksum */
	udp_packet[7] = 0xef;

    /* fake RTP headers, 12 bytes, and payload 16 bytes */
    rtp_header[ 0 ] = 0x80;
    rtp_header[ 1 ] = 0x1;
    rtp_header[ 2 ] = 0xb9;
    rtp_header[ 3 ] = 0x40;
    rtp_header[ 4 ] = 0x4b;
    rtp_header[ 5 ] = 0x82;
    rtp_header[ 6 ] = 0xe5;
    rtp_header[ 7 ] = 0x6c;
    rtp_header[ 8 ] = 0x50;
    rtp_header[ 9 ] = 0x68;
    rtp_header[ 10 ] = 0xe5;
    rtp_header[ 11 ] = 0x2b;
    rtp_header[ 12 ] = 0xc;
    rtp_header[ 13 ] = 0x3e;
    rtp_header[ 14 ] = 0x8e;
    rtp_header[ 15 ] = 0x4a;
    rtp_header[ 16 ] = 0x69;
    rtp_header[ 17 ] = 0x52;
    rtp_header[ 18 ] = 0x1b;
    rtp_header[ 19 ] = 0xfa;
    rtp_header[ 20 ] = 0x2;
    rtp_header[ 21 ] = 0xe0;
    rtp_header[ 22 ] = 0xb0;
    rtp_header[ 23 ] = 0x37;
    rtp_header[ 24 ] = 0x9f;
    rtp_header[ 25 ] = 0xd8;
    rtp_header[ 26 ] = 0x74;
    rtp_header[ 27 ] = 0x10;

	/* copy the payload just after the IP header */
	//memcpy(ip_packet + 5 * 4, FAKE_PAYLOAD, strlen(FAKE_PAYLOAD));
	memcpy(ip_packet + 20, udp_packet, 8);
	memcpy(ip_packet + 28, rtp_header, 28);

	/* dump the newly-created IP packet on terminal */
	for(i = 0; i < ip_packet_len; i++)
	{
		printf("0x%02x ", ip_packet[i]);
		if(i != 0 && ((i + 1) % 8) == 0)
		{
			printf("\n");
		}
	}
	if(i != 0 && ((i + 1) % 8) != 0) /* be sure to go to the line */
	{
		printf("\n");
	}


	/* Now, compress this fake IP packet.
	 *
	 * See http://rohc-lib.org/doc/latest/group__rohc__comp.html#ga99be8242b7bc4f442f4519461a99726b
	 * for details about rohc_compress in the API documentation.
	 */
    for (int j = 0; j < 30; j++ ){
	printf("\ncompress the fake IP packet, j = %d\n", j);
	rohc_packet_len = rohc_compress(compressor,
	                                ip_packet, ip_packet_len,
	                                rohc_packet, BUFFER_SIZE);
	if(rohc_packet_len <= 0)
	{
		fprintf(stderr, "compression of fake IP packet failed\n");
		goto release_compressor;
	}


	/* dump the ROHC packet on terminal */
	printf("\nROHC packet resulting from the ROHC compression:\n");
	for(i = 0; i < ((unsigned int) rohc_packet_len); i++)
	{
		printf("0x%02x ", rohc_packet[i]);
		if(i != 0 && ((i + 1) % 8) == 0)
		{
			printf("\n");
		}
	}
	if(i != 0 && ((i + 1) % 8) != 0) /* be sure to go to the line */
	{
		printf("\n");
	}

	int decomp_size = rohc_decompress(decompressor,
	                     rohc_packet, rohc_packet_len,
	                     decomp_packet, BUFFER_SIZE);

	if(0 == decomp_size)
	{
		printf("\ndecompression of fake IP packet failed.\n");
	}
    else {
    	printf("\nROHC packet resulting from the ROHC decompression:\n");
        for (int i = 0; i< decomp_size; i++) {
    		printf("0x%02x ", decomp_packet[i]);
    		if(i != 0 && ((i + 1) % 8) == 0)
    		{
    			printf("\n");
    		}
        }
    }

} // end of 10 times loop
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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