Thanks Didier. I tried capturing tcpdump on eth0 but it dint show complete info about the compressed packet and its size.
I have tried the same way as it is been given in tunnel.c with the following command : ./rohctunnel rohc0 remote 192.168.1.3 local 192.168.1.4 port 5000 and keeping this running on the background in both the systems(with appropriate addr) i executed the following commands: ip link set rohc0 up and ip -4 addr add 10.0.0.1/28 dev rohc0 Next I tried to ping from one system to another. I got the output statistics of the compressed packets on the system that i pinged as follows: c_generic.c:6377 check_ip_identification()] RND detected [c_generic.c:844 c_generic_encode()] SN = 139 [c_generic.c:6120 changed_dynamic_both_hdr()] check for changed fields in the outer IP header [c_generic.c:862 c_generic_encode()] send_static = 0, send_dynamic = 0 [c_generic.c:870 c_generic_encode()] ip_id = 0x0000, context_sn = 139 [c_generic.c:2230 update_variables()] ip_id delta = 0xffffff75 / 4294967157 [c_generic.c:2231 update_variables()] ip_id bits = 16 [c_generic.c:2241 update_variables()] sn bits=2 [c_generic.c:2599 decide_packet()] SO state [c_generic.c:2439 decide_SO_packet()] nr_ip_bits=16 nr_sn_bits=2 nr_of_ip_hdr=1 rnd=1 [c_generic.c:3566 code_UO0_packet()] code UO-0 packet (CID = 0) [cid.c:57 code_cid_values()] CID = 0 => no add-CID [c_generic.c:3587 code_UO0_packet()] F byte = 0x59 (CRC = 0x1 on 20 bytes) [c_generic.c:3490 code_UO_packet_tail()] outer IP-ID = 0x0000 [rohc_comp.c:362 rohc_compress()] ROHC size = 67 (feedback = 0, header = 3, payload = 64), output buffer size = 5120 sendto failed: Invalid argument (22) write_to_udp failed [rohc_comp.c:175 rohc_compress()] size of IP packet = 84 bytes [rohc_comp.c:198 rohc_compress()] IP protocol = 1 [rohc_comp.c:203 rohc_compress()] no profile found, using default IP profile [rohc_comp.c:1113 c_find_context()] using context CID = 0 [rohc_comp.c:269 rohc_compress()] selected compression profile = IP / Compressor (0x0004) [rohc_comp.c:1302 c_piggyback_get()] add 0 byte(s) of feedback data [rohc_comp.c:287 rohc_compress()] compress the packet #140 [c_generic.c:6352 check_ip_identification()] 1) old_id = 0x0000 new_id = 0x0000 [c_generic.c:6366 check_ip_identification()] 2) old_id = 0x0000 new_id = 0x0000 [c_generic.c:6377 check_ip_identification()] RND detected [c_generic.c:844 c_generic_encode()] SN = 140 [c_generic.c:6120 changed_dynamic_both_hdr()] check for changed fields in the outer IP header [c_generic.c:862 c_generic_encode()] send_static = 0, send_dynamic = 0 [c_generic.c:870 c_generic_encode()] ip_id = 0x0000, context_sn = 140 [c_generic.c:2230 update_variables()] ip_id delta = 0xffffff74 / 4294967156 [c_generic.c:2231 update_variables()] ip_id bits = 16 [c_generic.c:2241 update_variables()] sn bits=2 [c_generic.c:2599 decide_packet()] SO state [c_generic.c:2439 decide_SO_packet()] nr_ip_bits=16 nr_sn_bits=2 nr_of_ip_hdr=1 rnd=1 [c_generic.c:3566 code_UO0_packet()] code UO-0 packet (CID = 0) [cid.c:57 code_cid_values()] CID = 0 => no add-CID [c_generic.c:3587 code_UO0_packet()] F byte = 0x61 (CRC = 0x1 on 20 bytes) [c_generic.c:3490 code_UO_packet_tail()] outer IP-ID = 0x0000 [rohc_comp.c:362 rohc_compress()] ROHC size = 67 (feedback = 0, header = 3, payload = 64), output buffer size = 5120 sendto failed: Invalid argument (22) write_to_udp failed [rohc_comp.c:175 rohc_compress()] size of IP packet = 84 bytes [rohc_comp.c:198 rohc_compress()] IP protocol = 1 [rohc_comp.c:203 rohc_compress()] no profile found, using default IP profile [rohc_comp.c:1113 c_find_context()] using context CID = 0 [rohc_comp.c:269 rohc_compress()] selected compression profile = IP / Compressor (0x0004) [rohc_comp.c:1302 c_piggyback_get()] add 0 byte(s) of feedback data [rohc_comp.c:287 rohc_compress()] compress the packet #141 [c_generic.c:6352 check_ip_identification()] 1) old_id = 0x0000 new_id = 0x0000 [c_generic.c:6366 check_ip_identification()] 2) old_id = 0x0000 new_id = 0x0000 [c_generic.c:6377 check_ip_identification()] RND detected [c_generic.c:844 c_generic_encode()] SN = 141 [c_generic.c:6120 changed_dynamic_both_hdr()] check for changed fields in the outer IP header [c_generic.c:862 c_generic_encode()] send_static = 0, send_dynamic = 0 [c_generic.c:870 c_generic_encode()] ip_id = 0x0000, context_sn = 141 [c_generic.c:2230 update_variables()] ip_id delta = 0xffffff73 / 4294967155 [c_generic.c:2231 update_variables()] ip_id bits = 16 [c_generic.c:2241 update_variables()] sn bits=2 [c_generic.c:2599 decide_packet()] SO state [c_generic.c:2439 decide_SO_packet()] nr_ip_bits=16 nr_sn_bits=2 nr_of_ip_hdr=1 rnd=1 [c_generic.c:3566 code_UO0_packet()] code UO-0 packet (CID = 0) [cid.c:57 code_cid_values()] CID = 0 => no add-CID [c_generic.c:3587 code_UO0_packet()] F byte = 0x69 (CRC = 0x1 on 20 bytes) [c_generic.c:3490 code_UO_packet_tail()] outer IP-ID = 0x0000 [rohc_comp.c:362 rohc_compress()] ROHC size = 67 (feedback = 0, header = 3, payload = 64), output buffer size = 5120 sendto failed: Invalid argument (22) write_to_udp failed [rohc_comp.c:175 rohc_compress()] size of IP packet = 84 bytes [rohc_comp.c:198 rohc_compress()] IP protocol = 1 [rohc_comp.c:203 rohc_compress()] no profile found, using default IP profile [rohc_comp.c:1113 c_find_context()] using context CID = 0 According to the program the compressed statistics has to be shown on one system and the decompressed statistics has to be shown on the other system.. But I am getting only compressed statistics on the system which I ping..But not receiving the decompressed statisics on the other system.. And also when i terminate the ping application i says 100% packet loss.. What might be the problem.?? Could ypu please help out.. Thanks and Regards, Ramya. On Wed, May 5, 2010 at 5:56 PM, Didier Barvaux < [email protected]> wrote: > Hi Ramya, > > My answer is below. Please, keep sending your questions on the mailing > list so that everyone might read the discussion and eventually learn > something from it. > > > > I tried to send it through eth0 but still when i execute the command : > > > > ./rohctunnel eth0:rohc0 remote 192.168.1.4 local 192.168.1.2 port 5000 > > the output goes as follows: > > > > [...] > > > > This keeps coming and there is no other output that i can see. I am > > new to this So I dont have much idea how to proceed. Can you pls help > > And can you also tell me where and how to check if the packets are > > compressed and decompressed and after executing which command the > > packets will b compressed. > > The interface "eth0" is your normal Ethernet interface. The rochtunnel > tool creates a new virtual interface ("eth0:rohc0" in your case) that > you should use to send the network packets that you want to compress. > The virtual interface supersedes the normal interface for traffic you > want to compress. > > Once started, the rohctunnel tool waits for packets on the "eth0:rohc0" > interface. Whenever it reads one packet, it compresses the packet to > create a ROHC packet and then sends this ROHC packet to the "eth0" > interface. The header of the rohctunnel source code contains a figure > that describes this, see > > http://bazaar.launchpad.net/%7Edidier-barvaux/rohc/main/annotate/head%3A/app/tunnel/tunnel.c > > So, on the "eth0:rohc0" interface, tcpdump may capture uncompressed > packets that will be soon compressed by the rohctunnel tool. On the > "eth0" interface tcpdump may capture compressed ROHC packets that the > rohctunnel tool just compressed. > > Here is a figure to explain that (use a fixed font to read it): > > uncompressed +------------+ +------------+ > packet to --> | eth0:rohc0 | --> | rohctunnel | > compress +------------+ +------------+ > | > | compressed ROHC packet > | encapsulated in UDP > | > | +------------+ > +--> | eth0 | > +------------+ > > Does it help you ? > > Regards, > > Didier Barvaux > Viveris Technologies > http://www.tech.viveris.com/opensource/ >
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