Re: tcp packet split
On Sun, Jan 19, 2014 at 2:31 AM, net.study@gmail.com wrote: How does the application level recognize each segment bridge in tcp stream ? i.e packe a 30bytes packet b 50bytes packet a 20bytes And why it is possible for one packet to contain uncontinuous part of different user protocol packets? It's not a kernel question in my opinion, but... Take a look here: Segmentation is the process of carving up information into smaller pieces. The documentation for Transmission Control Protocol (TCP) refrers to what it calls 'data streams'. A data stream is really nothing more than a series of zeroes and ones that represent information. TCP receives data from an application and segments the data into pieces. This segmentation is necessary so that the information can be placed inside the TCP data field. TCP reassembles segments into a data stream and feeds that data stream to the application. The best known example of this activity is HTTP transfer of a web page. The web server loads a web page from disk, encapsulates the web page text in HTTP headers, the passes the HTTP encoded stream of text to TCP. TCP segments the text stream for transport across the network. The networking software (the stack) receives the TCP data segments and reassembles the HTTP stream of text, which your web browser reads, and renders as a web page. http://www.inetdaemon.com/tutorials/internet/tcp/segmentation.shtml 在 2014-1-18，22:04，Augusto Mecking Caringi augustocari...@gmail.com 写道： On Sat, Jan 18, 2014 at 12:08 AM, net.study@gmail.com wrote: Hi : If one tcp data packet contains serveral user protocol packet. . How is it splitter over to separate packet ? Hi, It's an application protocol level problem and it's application job to do this. This is also called TCP desegmentation or TCP reassembly. Take a look here: http://wiki.wireshark.org/TCP_Reassembly Regards. -- Augusto Mecking Caringi -- Augusto Mecking Caringi ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: How to access a DRM CRTC's scan out buffer?
On Fri, Jan 17, 2014 at 11:08 AM, Peter Teoh htmldevelo...@gmail.comwrote: As indicated here: http://www.botchco.com/agd5f/?p=51 the input to CRTC is the framebuffer, and output of CRTC is already monitor-level information...which is meaningless to you. So but best bet is to get it at the framebuffer level? Yes. I will look into the code again at the framebuffer level. Thanks and Regards, Sannu K ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: tcp packet split
On Sun, Jan 19, 2014 at 2:31 AM, net.study@gmail.com wrote: How does the application level recognize each segment bridge in tcp stream ? i.e packe a 30bytes packet b 50bytes packet a 20bytes And why it is possible for one packet to contain uncontinuous part of different user protocol packets? Take a look here also: http://www.wireshark.org/docs/wsdg_html_chunked/ChDissectReassemble.html -- Augusto Mecking Caringi ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: tcp packet split
On Sun, Jan 19, 2014 at 2:31 AM, net.study@gmail.com wrote: And why it is possible for one packet to contain uncontinuous part of different user protocol packets? Whatever gave you the idea that's possible? There's absolutely zero provision in the Internet standards for one packet to carry data for multiple packets. Not only are there no provisions folr multiple L3/4 headers in a packet, one of the more interesting challenges for firewall designers is that a fragmented packet may have *zero* L3/4 headers in it. The only way you'd encounter this would be if you have packet encapsulation on a VPN or similar tunnel, and it decided to pack multiple short packets into a tunneling packet - but in that case, (a) the lower-level packet is only carrying a stream of data and (b) the tunnelled stream is, in general, unaware that it's being tunnelled (and thus is carrying around full L1-L4 headers). And, in general, VPNs don't actually pack packets like that - it tends to totally screw up RTT and jitter calculations. pgpnu1XUN8olI.pgp Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
