Hi,Darek, >I've found >functions for global files, maybe they are the same). I'd like to >check when these files where introduced (from what kernel version they >are available) Support for kernel network namesapces was added with kernel 2.6.29. It is basically based on adding an object called "net_ns" to the process descriptor, and instance of struct net, which represents a network namesapce. You can think of such object as representing the network state of a process, including all stats, sockets, devices, tables, and so on. This net_ns is a member of an object called nsproxy, which includes pointers to 4 other namesapces (uts, mnt, pid and ipc). >and there is no information about network >namespaces at all (google, stackoverflow, man pages, kernel docs) This is not really so. Look for example in the following: Namespaces and Cgroups – the basis of Linux Containers by Rami Rosen http://files.meetup.com/18720713/Namespaces_Cgroups_Conatiners.pdf "Resource management: Linux kernel Namespaces and cgroups by Rami Rosen http://www.haifux.org/lectures/299/netLec7.pdf Namespaces in operation, part 7: Network namespaces by Jake Edge https://lwn.net/Articles/580893/ Introduction to Network Namepaces - David Mahler https://www.youtube.com/watch?v=_WgUwUf1d34 (Shamless plug, I am the owner of the first two links...) Hope this helps, Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 22 January 2016 at 10:34, dariusz ostolski <dariusz.ostolski@xxxxxxxxx> wrote: > Hello, > > My name is Darek Ostolski, I'm computer enthusiast and hobbyst (also a > developer). > If this is incorrect mailing list excuse me and please point to > the appropriate place to ask this kind of question. I couldn't find > any other more > appropriate place. > > I have a process that is in the separate net namespace (basically a > container) and I want to check opened connections for that process. I > have a kernel 4.3.3. > My experiments showed that this information is available in > /proc/[pid]/net/tcp|tcp6 files. For example for a global > /proc/net/tcp6 shows following opened ports: > > root@host:~# cat /proc/net/tcp6 > sl local_address remote_address > st tx_queue rx_queue tr tm->when retrnsmt uid timeout > inode > 0: 00000000000000000000000000000000:01BD > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 22882 1 ffff88040de7b240 100 0 0 10 0 > 1: 00000000000000000000000000000000:008B > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 22883 1 ffff88040de7a9c0 100 0 0 10 0 > 2: 00000000000000000000000000000000:0050 > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 1214363 1 ffff880077ed9340 100 0 0 10 0 > 3: 00000000000000000000000000000000:0016 > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 21933 1 ffff880400a33140 100 0 0 10 0 > 4: 00000000000000000000000000000000:445C > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 1000 0 29904 1 ffff880400a32040 100 0 0 10 0 > > And for a process running in container I have: > root@host:~# cat /proc/30518/net/tcp6 > sl local_address remote_address > st tx_queue rx_queue tr tm->when retrnsmt uid timeout > inode > 0: 0000000000000000FFFF00000100007F:1F45 > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 1211206 1 ffff880364fcb380 100 0 0 10 0 > 1: 00000000000000000000000000000000:1F49 > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 1215425 1 ffff8802befd0200 100 0 0 10 0 > 2: 00000000000000000000000000000000:1F90 > 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 > 00000000 0 0 1215421 1 ffff880077ed8240 100 0 0 10 0 > > > So I see that there are opened ports that are not visible on host > level but are visible at a container level for example 1F90 -> which > is basically 8080. > > > I'd like to ask following questions: > 1. Where can I find documentation for /proc/[pid]/net/tcp|tcp6 files? > All I could find was documentation about global file(i.e. > /proc/net/tcp|tcp6) and there is no information about network > namespaces at all (google, stackoverflow, man pages, kernel docs) > 2. Could You confirm that in these files I'll see all connections that > are specific for a given process even if this process is in separate > network namespace? (so I dont have to enter target net/pid namespace > to read their global /proc/net/tcp|tcp6 files) > 3. I've grep kernel source code and tried to find where > /proc/[pid]/net/tcp|tcp6 files are created but I couldn't (I've found > functions for global files, maybe they are the same). I'd like to > check when these files where introduced (from what kernel version they > are available) and if I can confirm my findings directly from kernel > sources (that I'll see connections from separate net namespace without > actually entering that namespace). This is source code that I've found: > http://lxr.free-electrons.com/source/net/ipv4/tcp_ipv4.c?v=4.3#L2261 > > But as I wrote I don't know how it is related to to files from > /proc/[pid]/net/tcp|tcp6 > > > Thank You in advance for your help. > > -- > Regards, > Darek > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
