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VIDEOS 》 Linux ioctl() API interface

Refer:
net-tools (ioctl APIs - user-space side):
net-tools sourceforge.net - http://net-tools.sourceforge.net
net-tools sourceforge.net Project - https://sourceforge.net/projects/net-tools
net-tools Linux Foundation Wiki - https://wiki.linuxfoundation.org/networking/net-tools
net-tools Git source - https://sourceforge.net/p/net-tools/code/ci/master/tree
ifconfig.c - https://sourceforge.net/p/net-tools/code/ci/master/tree/ifconfig.c

Refer:
Wiki:
Carrier grade - https://en.wikipedia.org/wiki/Carrier_grade
Carrier Grade Linux - https://en.wikipedia.org/wiki/Carrier_Grade_Linux
High Availability (HA) - https://en.wikipedia.org/wiki/High_availability
Redundancy(engineering) - https://en.wikipedia.org/wiki/Redundancy_(engineering)

Kernel Source (ioctl APIs - kernel-space side):
/net/core/dev_ioctl.c - http://elixir.free-electrons.com/linux/latest/source/net/core/dev_ioctl.c
/net/core/dev.c - http://elixir.free-electrons.com/linux/latest/source/net/core/dev.c
The Linux Channel video series:
Linux Kernel net_device data-structure - http://the-linux-channel.the-toffee-project.org/index.php?page=41-videos-linux-kernel-net-device-data-structure
Linux Kernel Networking Sub-system - http://the-linux-channel.the-toffee-project.org/index.php?page=45-videos-linux-kernel-networking-sub-system
Linux Kernel /proc Interface - http://the-linux-channel.the-toffee-project.org/index.php?page=106-videos-linux-kernel-proc-interface
Linux Kernel sk_buff data-structure - Episode-1 to Episode-10 - http://the-linux-channel.the-toffee-project.org/index.php?page=47-videos-linux-kernel-sk-buff-data-structure
Linux Kernel sk_buff data-structure - Episode-11 to Episode-18 - http://the-linux-channel.the-toffee-project.org/index.php?page=111-videos-linux-kernel-sk-buff-data-structure

Download this episode my entire kernel module sample code, make file, clean script HERE.

Refer:
Device Drivers, Part 9: I/O Control in Linux - by Anil Kumar Pugalia <email_at_sarika-pugs_dot_com> - http://opensourceforu.com/2011/08/io-control-in-linux/
The Linux Kernel Module Programming Guide - Chapter 7. Talking To Device Files - http://tldp.org/LDP/lkmpg/2.6/html/x892.html
(NOTE: Sample example source-code mentioned here will not work as it is in newer kernels. It needs porting.)

Refer:
/include/linux/uaccess.h - copy_from_user(), copy_to_user() - http://elixir.free-electrons.com/linux/latest/source/include/linux/uaccess.h
/arch/x86/include/asm/uaccess_32.h - raw_copy_from_user(), raw_copy_to_user() [x86 32-bit] http://elixir.free-electrons.com/linux/latest/source/arch/x86/include/asm/uaccess_32.h
/arch/x86/include/asm/uaccess_64.h - raw_copy_from_user(), raw_copy_to_user() [x86 64-bit] http://elixir.free-electrons.com/linux/latest/source/arch/x86/include/asm/uaccess_64.h
/arch/arm/include/asm/uaccess.h - raw_copy_from_user(), raw_copy_to_user() [arm] http://elixir.free-electrons.com/linux/latest/source/arch/arm/include/asm/uaccess.h
/arch/arm64/include/asm/uaccess.h- raw_copy_from_user(), raw_copy_to_user() [arm 64-bit] http://elixir.free-electrons.com/linux/latest/source/arch/arm64/include/asm/uaccess.h

As discussed in the video (Episode 4), we cannot use memcpy() to communicate between user-space applications (processes). Since each process has its own virtual memory space. Instead we need to use standard Linux predefined IPC (for example: sockets, message queues, pipes, signals and so on), which in turn built via APIs such as: copy_from_user() and copy_to_user().
copy_from_user() and copy_to_user()
Notice: copy_from_user() and copy_to_user() looks similar to memcpy() in terms of their function arguments.
copy_from_user() and copy_to_user() vs memcpy()
Here is the Kernel source API flow of the copy_from_user() and copy_to_user() APIs. As discussed in the video, eventually it transitions from architecture (or platform) independent code to the platform (or hardware/CPU) dependent code:
copy_from_user() and copy_to_user() Kernel Source API path



Suggested Topics:


Video Episodes :: Linux Kernel programming

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Monday' 18-Jul-2022
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Saturday' 13-Mar-2021

Linux Kernel /proc Interface ↗
Wednesday' 18-May-2022
/proc is one of the most popular kernel to user-space interface which you can leverage to add an interface to your Kernel code such as Kernel modules, Kernel Device Drivers, etc. Personally I prefer /proc interface than other alternatives such as /sysfs, ioctl() and so on for my personal Kernel modules/stack. So here is my detailed multi-episode Youtube video series on /sysfs Interface. I also conduct sessions/classes on Systems and Network software programming and architecture.

Linux Kernel /sysfs Interface ↗
Saturday' 14-May-2022
/sysfs is one of the most popular kernel to user-space interface which you can leverage to add an interface to your Kernel code such as Kernel modules, Kernel Device Drivers, etc. Although personally I prefer /proc interface than other alternatives such as /sysfs, ioctl() and so on for my personal Kernel modules/stack. So here is my detailed multi-episode Youtube video series on /sysfs Interface.

Linux Operating System - User-space Processes ↗
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Linux Kernel - Containers and Namespaces ↗
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Linux Kernel Compilation ↗
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Linux Kernel Programming ↗
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Linux ioctl() API interface ↗
Saturday' 13-Mar-2021
Watch detailed videos and read topics on Linux Kernel Programming and Linux ioctl() API interface

Linux Kernel Architecture ↗
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Linux Kernel Programming - Device Drivers ↗
Saturday' 13-Mar-2021
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Monday' 18-Jul-2022
Often aspiring students may have this question, that what is the purpose of Linux Kernel Development. Since Linux Kernel is very mature and it has almost everything one would need. Usually, we need custom kernel development in the case of any new driver development for new upcoming hardware. And this happens on and on. But at times we may also come across few features/modules/components which are already provided by the Linux Kernel which are not adequate or atleast not the way we exactly intended to use. So, this is the real-world example, sometimes no matter what Linux Kernel provides as a part of stock Kernel/OS features, sometimes we have to write our own custom kernel stack or module(s) which can specifically cater our exact needs.

Roadmap - How to become Systems Software Developer ↗
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The Linux Channel :: Sponsors ↗
Monday' 30-May-2022
Here is a list of all The Linux Channel sponsors/donors (individual/companies).

Linux Kernel /sysfs Interface ↗
Saturday' 14-May-2022
/sysfs is one of the most popular kernel to user-space interface which you can leverage to add an interface to your Kernel code such as Kernel modules, Kernel Device Drivers, etc. Although personally I prefer /proc interface than other alternatives such as /sysfs, ioctl() and so on for my personal Kernel modules/stack. So here is my detailed multi-episode Youtube video series on /sysfs Interface.

Support, Donate and Contribute - The Linux Channel ↗
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Help shape the future and make an impact by donating/sponsor The Linux Channel. Your donation will transform lives !

Research Socket overhead in Linux vs Message Queues and benchmarking ↗
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Linux Kernel Data-Structures ↗
Saturday' 13-Mar-2021
Here is a quick reference of important Linux Kernel Data Structures of various assorted Kernel Subsystems such as: Process, Memory Management, Networking, File System, Device Drives, IPC and so on. So when you write custom Kernel code, it is often you may need to populate a new instance of one of these data-structures or just access the existing ones. Hence it is very important to know some of these and get familiarized with. You can bookmark this page, so that you can use this as a quick reference when you write your own custom Linux Kernel Modules.

IPUtils - Source Code Walk ↗
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Network Packet Processing Hardware Offload ↗
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Bluefish IDE - a simple versatile light-weight best editor to edit kernel source files, html files, c source code, text files, SQL schema and so on ↗
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