I was doing a general code walk of Tun/Tap drivers in /drivers/net/tun.c and /drivers/net/tap.c, which is when I stumbled across its ioctl handlers/implementation and then started comparing with generic /net/core/dev_ioctl.c. Network port ioctl support is pretty vital so that whenever we control/configure any network ports (physical or virtual ports, such as tun/tap, veth, lo, dummy, so on), the configuration is passed on from user-space to kernel-space port drivers via ioctl (also known as IO control) APIs.
There are various ioctl commands/instructions which these kernel network drivers support which you can find in /include/uapi/linux/sockios.h as shown below:
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions of the socket-level I/O control calls.
*
* Version: @(#)sockios.h 1.0.2 03/09/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _LINUX_SOCKIOS_H
#define _LINUX_SOCKIOS_H
#include <asm/bitsperlong.h>
#include <asm/sockios.h>
/* Linux-specific socket ioctls */
#define SIOCINQ FIONREAD
#define SIOCOUTQ TIOCOUTQ /* output queue size (not sent + not acked) */
#define SOCK_IOC_TYPE 0x89
/*
* the timeval/timespec data structure layout is defined by libc,
* so we need to cover both possible versions on 32-bit.
*/
/* Get stamp (timeval) */
#define SIOCGSTAMP_NEW _IOR(SOCK_IOC_TYPE, 0x06, long long[2])
/* Get stamp (timespec) */
#define SIOCGSTAMPNS_NEW _IOR(SOCK_IOC_TYPE, 0x07, long long[2])
#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
/* on 64-bit and x32, avoid the ?: operator */
#define SIOCGSTAMP SIOCGSTAMP_OLD
#define SIOCGSTAMPNS SIOCGSTAMPNS_OLD
#else
#define SIOCGSTAMP ((sizeof(struct timeval)) == 8 ? \
SIOCGSTAMP_OLD : SIOCGSTAMP_NEW)
#define SIOCGSTAMPNS ((sizeof(struct timespec)) == 8 ? \
SIOCGSTAMPNS_OLD : SIOCGSTAMPNS_NEW)
#endif
/* Routing table calls. */
#define SIOCADDRT 0x890B /* add routing table entry */
#define SIOCDELRT 0x890C /* delete routing table entry */
#define SIOCRTMSG 0x890D /* unused */
/* Socket configuration controls. */
#define SIOCGIFNAME 0x8910 /* get iface name */
#define SIOCSIFLINK 0x8911 /* set iface channel */
#define SIOCGIFCONF 0x8912 /* get iface list */
#define SIOCGIFFLAGS 0x8913 /* get flags */
#define SIOCSIFFLAGS 0x8914 /* set flags */
#define SIOCGIFADDR 0x8915 /* get PA address */
#define SIOCSIFADDR 0x8916 /* set PA address */
#define SIOCGIFDSTADDR 0x8917 /* get remote PA address */
#define SIOCSIFDSTADDR 0x8918 /* set remote PA address */
#define SIOCGIFBRDADDR 0x8919 /* get broadcast PA address */
#define SIOCSIFBRDADDR 0x891a /* set broadcast PA address */
#define SIOCGIFNETMASK 0x891b /* get network PA mask */
#define SIOCSIFNETMASK 0x891c /* set network PA mask */
#define SIOCGIFMETRIC 0x891d /* get metric */
#define SIOCSIFMETRIC 0x891e /* set metric */
#define SIOCGIFMEM 0x891f /* get memory address (BSD) */
#define SIOCSIFMEM 0x8920 /* set memory address (BSD) */
#define SIOCGIFMTU 0x8921 /* get MTU size */
#define SIOCSIFMTU 0x8922 /* set MTU size */
#define SIOCSIFNAME 0x8923 /* set interface name */
#define SIOCSIFHWADDR 0x8924 /* set hardware address */
#define SIOCGIFENCAP 0x8925 /* get/set encapsulations */
#define SIOCSIFENCAP 0x8926
#define SIOCGIFHWADDR 0x8927 /* Get hardware address */
#define SIOCGIFSLAVE 0x8929 /* Driver slaving support */
#define SIOCSIFSLAVE 0x8930
#define SIOCADDMULTI 0x8931 /* Multicast address lists */
#define SIOCDELMULTI 0x8932
#define SIOCGIFINDEX 0x8933 /* name -> if_index mapping */
#define SIOGIFINDEX SIOCGIFINDEX /* misprint compatibility :-) */
#define SIOCSIFPFLAGS 0x8934 /* set/get extended flags set */
#define SIOCGIFPFLAGS 0x8935
#define SIOCDIFADDR 0x8936 /* delete PA address */
#define SIOCSIFHWBROADCAST 0x8937 /* set hardware broadcast addr */
#define SIOCGIFCOUNT 0x8938 /* get number of devices */
#define SIOCGIFBR 0x8940 /* Bridging support */
#define SIOCSIFBR 0x8941 /* Set bridging options */
#define SIOCGIFTXQLEN 0x8942 /* Get the tx queue length */
#define SIOCSIFTXQLEN 0x8943 /* Set the tx queue length */
/* SIOCGIFDIVERT was: 0x8944 Frame diversion support */
/* SIOCSIFDIVERT was: 0x8945 Set frame diversion options */
#define SIOCETHTOOL 0x8946 /* Ethtool interface */
#define SIOCGMIIPHY 0x8947 /* Get address of MII PHY in use. */
#define SIOCGMIIREG 0x8948 /* Read MII PHY register. */
#define SIOCSMIIREG 0x8949 /* Write MII PHY register. */
#define SIOCWANDEV 0x894A /* get/set netdev parameters */
#define SIOCOUTQNSD 0x894B /* output queue size (not sent only) */
#define SIOCGSKNS 0x894C /* get socket network namespace */
/* ARP cache control calls. */
/* 0x8950 - 0x8952 * obsolete calls, don't re-use */
#define SIOCDARP 0x8953 /* delete ARP table entry */
#define SIOCGARP 0x8954 /* get ARP table entry */
#define SIOCSARP 0x8955 /* set ARP table entry */
/* RARP cache control calls. */
#define SIOCDRARP 0x8960 /* delete RARP table entry */
#define SIOCGRARP 0x8961 /* get RARP table entry */
#define SIOCSRARP 0x8962 /* set RARP table entry */
/* Driver configuration calls */
#define SIOCGIFMAP 0x8970 /* Get device parameters */
#define SIOCSIFMAP 0x8971 /* Set device parameters */
/* DLCI configuration calls */
#define SIOCADDDLCI 0x8980 /* Create new DLCI device */
#define SIOCDELDLCI 0x8981 /* Delete DLCI device */
#define SIOCGIFVLAN 0x8982 /* 802.1Q VLAN support */
#define SIOCSIFVLAN 0x8983 /* Set 802.1Q VLAN options */
/* bonding calls */
#define SIOCBONDENSLAVE 0x8990 /* enslave a device to the bond */
#define SIOCBONDRELEASE 0x8991 /* release a slave from the bond*/
#define SIOCBONDSETHWADDR 0x8992 /* set the hw addr of the bond */
#define SIOCBONDSLAVEINFOQUERY 0x8993 /* rtn info about slave state */
#define SIOCBONDINFOQUERY 0x8994 /* rtn info about bond state */
#define SIOCBONDCHANGEACTIVE 0x8995 /* update to a new active slave */
/* bridge calls */
#define SIOCBRADDBR 0x89a0 /* create new bridge device */
#define SIOCBRDELBR 0x89a1 /* remove bridge device */
#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
#define SIOCBRDELIF 0x89a3 /* remove interface from bridge */
/* hardware time stamping: parameters in linux/net_tstamp.h */
#define SIOCSHWTSTAMP 0x89b0 /* set and get config */
#define SIOCGHWTSTAMP 0x89b1 /* get config */
/* Device private ioctl calls */
/*
* These 16 ioctls are available to devices via the do_ioctl() device
* vector. Each device should include this file and redefine these names
* as their own. Because these are device dependent it is a good idea
* _NOT_ to issue them to random objects and hope.
*
* THESE IOCTLS ARE _DEPRECATED_ AND WILL DISAPPEAR IN 2.5.X -DaveM
*/
#define SIOCDEVPRIVATE 0x89F0 /* to 89FF */
/*
* These 16 ioctl calls are protocol private
*/
#define SIOCPROTOPRIVATE 0x89E0 /* to 89EF */
#endif /* _LINUX_SOCKIOS_H */So you can find some of the ioctl commands are supported in the Tun/Tap driver source, vs the general implementation you can find in the /net/core/dev_ioctl.c. Here is a video episode in which I cover about the same in depth:
Refer:
Linux (user-space) RAW Socket Programming – Generate Layer-3 IP multicast OSPF Packets ↗
Linux (user-space) RAW Socket Programming – Generate Layer-2 multicast STP Packets ↗
Net-Tools Package – Source Code Walk – ifconfig Command – Part 1 ↗
The Linux Channel Videos ↗
ifconfig source-code ↗
net-tools github ↗
ifconfig commands ↗
Refer Linux Kernel source:
/drivers/net/tap.c ↗
/drivers/net/tun.c ↗
/net/core/dev_ioctl.c ↗
/include/uapi/linux/sockios.h ↗