Content

• What is KSMBD?
• Under PFIF
• Git
• Maintainers
• Bug reports or contribution
• Features
• Supported Linux Kernel Versions
• KSMBD architecture

What is KSMBD?

KSMBD is an opensource In-kernel CIFS/SMB3 server created by Namjae Jeon for Linux Kernel. It's an implementation of SMB/CIFS protocol in kernel space for sharing files and IPC services over network. Initially the target is to provide improved file I/O performances, but the bigger goal is to have some new features which are much easier to develop and maintain inside the kernel and expose the layers fully. Directions can be attributed to sections where SAMBA is moving to few modules inside the kernel to have features like RDMA(Remote direct memory access) to work with actual performance gain.

Under PFIF

This code was developed in participation with the Protocol Freedom Information Foundation.

Please see

• http://samba.org/samba/PFIF/ for more details.

Git

The development git tree is available at

• https://github.com/cifsd-team/ksmbd
• https://github.com/cifsd-team/ksmbd-tools

Maintainers

• Namjae Jeon linkinjeon@kernel.org

Bug reports or contribution

For reporting bugs and sending patches, please send the patches to the following mail address:

• linkinjeon@kernel.org

or open issues/send PRs to KSMBD.

Installing as a stand-alone module

Install prerequisite package for Fedora, RHEL:

    yum install kernel-devel-$(uname -r)

Build step:

    make
    sudo make install

To load the driver manually, run this as root:

    modprobe ksmbd

Installing as a part of the kernel

1. Let's take [linux] as the path to your kernel source dir.

   cd [linux]
   cp -ar ksmbd [linux]/fs/

2. edit [linux]/fs/Kconfig

   source "fs/cifs/Kconfig"
   +source "fs/ksmbd/Kconfig"
   source "fs/coda/Kconfig"

3. edit [linux]/fs/Makefile

   obj-$(CONFIG_CIFS)              += cifs/
   +obj-$(CONFIG_SMB_SERVER)       += ksmbd/
   obj-$(CONFIG_HPFS_FS)           += hpfs/

4. make menuconfig and set ksmbd

   [*] Network File Systems  --->
       <M>   SMB server support

build your kernel

Features

Implemented

1. SMB1(CIFS), SMB2/3 protocols for basic file sharing
2. Dynamic crediting
3. Compound requests
4. oplock/lease
5. Large MTU
6. NTLM/NTLMv2
7. Auto negotiation
8. HMAC-SHA256 Signing
9. Secure negotiate
10. Signing Update
11. Pre-authentication integrity(SMB 3.1.1)
12. SMB3 encryption(CCM, GCM)
13. SMB direct(RDMA)
14. Win-ACL
15. Kerberos
16. Multi-channel

Planned

1. Durable handle v1/v2
2. Persistent handles
3. Directory lease

Supported Linux Kernel Versions

• Linux Kernel 5.4 or later

KSMBD architecture

               |--- ...
       --------|--- ksmbd/3 - Client 3
       |-------|--- ksmbd/2 - Client 2
       |       |         _____________________________________________________
       |       |        |- Client 1                                           |
<--- Socket ---|--- ksmbd/1   <<= Authentication : NTLM/NTLM2, Kerberos(TODO)|
       |       |      | |      <<= SMB : SMB1, SMB2, SMB2.1, SMB3, SMB3.0.2,  |
       |       |      | |                SMB3.1.1                             |
       |       |      | |_____________________________________________________|
       |       |      |
       |       |      |--- VFS --- Local Filesystem
       |       |
KERNEL |--- ksmbd/0(forker kthread)
---------------||---------------------------------------------------------------
USER           ||
               || communication using NETLINK
               ||  ______________________________________________
               || |                                              |
        ksmbd.mountd <<= DCE/RPC, WINREG                         |
               ^  |  <<= configure shares setting, user accounts |
               |  |______________________________________________|
               |
               |------ smb.conf(config file)
               |
               |------ ksmbdpwd.db(user account/password file)
                            ^
  ksmbd.adduser ---------------|

Performance

1. ksmbd vs samba performance comparison using iozone (Linux Client)
   
   

2. ksmbd vs samba performance comparison using fileop (Linux Client)
   
   

3. ksmbd vs samba performance comparison using CrystalDiskMark (Windows Client)